DESC:FIELD OF THE INVENTION

The present invention relates to an improved compact shieldless projection optical system and method thereof. Further, the improved compact shieldless optical system provides minimization of over-loss of flux and such system is employed in an automobile. The improved shieldless projection optical system is used for projection of multifunctional light beam that illuminates road surface.

BACKGROUND OF THE INVENTION

An optical system usually comprises one or more components which are used for reflection or refraction of the light rays to produce a desired effect. These optical systems are primarily employed in an automobile/vehicle that illuminates road surface. Generally, optical systems uses elliptical shaped reflector along with a shield to produce low beam from the optical system. In such type of arrangement, there is a phenomenon of loss of light rays and loss of flux from the optical system, as the light reflected by the reflector was majorly absorbed by the shield.
Another problem associated with conventional optical system is its high cost due to presence of numerous optical elements. Further, optical elements are placed at a far distance in the conventional optical system. As a result, there is an increase in the overall dimension of the conventional optical system. Further, the conventional optical system projects light beam whose focal point is present in between reflector and condenser lens. Thus, considerable distance needs to be maintained between them to achieve high photometric efficiency for projected light beam from an automobile. Due to this, large space is required for placing optical elements in the conventional system, wherein automobile such as two-wheeler or three-wheeler suffers from space limitation. This also causes bulkiness/ additional weight in an automobile which is undesirable.

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Also, the arrangement available in conventional optical system has presence of the shield which absorbs fraction of light rays because of which projected low beam has low photometric efficiency. Further, requirement of shield is important for projecting low beam. Thus, the low photometric efficient projected light beam hampers visibility of the user/driver of an automobile to see nearby objects. Hence, this is one of the major factors which leads to road accident and other such road disasters.
Various optical systems have been used in different field of the technology such as automobile, LED lighting, etc. Some of these are as follows:
US10876694 discloses a light beam projection device which comprises of a plurality of light sources, a lens whose input surface is provided with plurality of convergent optics that are domed outward and output surface has plurality of sub lenses of parabolic shape and a projection lens. The plurality of the light sources emits light rays which falls onto the lens inner surface. The input surface causes formation of virtual images because the lens input surface has plurality of convergent optics that are doomed outward. The virtual images are formed behind the light sources. The light rays from plurality of the light sources act as a secondary light source for projection lens which received light from the output surface of the lens. Since the output surface of the lens is parabolic in shape it is ensured that light rays form the virtual images are well received by the projection lens.
US ‘694 is primarily for an optical system in which plurality of virtual images are formed and since this plurality of virtual images may have an interference with each other hence necessary arrangement of optical member is required. Another disadvantage is that since virtual images are formed at a far-off distance from the lens, as a result of which the optical system is bigger in size and need more space to be fitted in the automobile.
US’ 694 is unable to project multifunctional light beam from the optical system due to which different type of light beam will require different optical system to install in an automobile thereby causing space limitation especially in two-wheeler and three-wheeler.
JP5677410B2 discloses a lighting module for an automobile which comprises of an optical member, pair of concave shaped reflectors arranged in such a way that reflected rays from them are complementary to each other, light source and a shield. The light source emits light rays which falls onto the pair of concave shaped reflector. The reflectors produce plurality of reflected rays in such a manner that reflected rays from the first reflector is focused towards the second focal point of the second reflector and the reflected rays of the second reflector is focused onto the second focal point of first reflector to avoid interference of reflected rays. The shield placed in front of the pair of the concave reflector forms a cut-off line which is further projected to the optical member in order to project low beam.
JP’410 discloses presence of a shield which absorbs fraction of reflected rays thus causing over loss of flux during low beam projection. JP’410 optical module is arranged in such a way that it is able to project low beam only from the optical member and thus fails to produce high beam and other light requirement such as fog light and the structure is bulky.
DE 102006044640 discloses a lighting unit which comprises of two light emitting diodes, a light guiding body, a socket to switch ON/OFF. LED chip as a light source emits light towards primary optic which is input surface of the light guiding body. The light guiding body has curved surface in order to provide pathways for total internal reflection of light. The output surface of the light guiding body act as a secondary optic which will project light beam. The LED light source are connected with a pair of sockets in such a way that when one light source is switch ON it provides light rays to the upper interface of the light guiding unit. In order to switch for high beam two light sources are switch ON through switching mechanism so that light rays strike at upper and lower interface of the light guiding body.
DE’640 discloses a lighting unit which has several optical elements due to which it will consume more space for installation which will be difficult in case of small size automobiles such as two-wheeler and three-wheeler.
DE’640 is unable to provide multifunctional light beam from a single optical system. Due to which projection of different types of light beams will require additional optical elements and additional optical systems hence there will be a space limitation to install it in the automobile.
Also, the conventional optical systems causes over-loss of flux which is mainly due to presence of the shield in the optical arrangement. It is also evident that large distance between optical elements causes conventional optical system to be bulky. Thereby, conventional optical system requires more space to place optical elements. Accordingly, a need felt for an optical system which is far more effective, specific, efficient, compact, simple, economical and can produce multifunctional light beam. As a result, an automobile user can see the distant as well as nearby object/s clearly.
It is therefore an object of the present invention to provide an improved optical system which results minimization in over-loss of flux. Such an improved optical system is compact, simple, and economical in nature. Additionally, improved optical system can be used for projection of multi-functional light beam.
Accordingly, it is the principal object of the present invention to solve the aforesaid problems existing in the state of art for economic and efficient manufacturing of the optical systems with minimal manufacturing defects.
SUMMARY OF THE INVENTION
The present invention relates to an improved compact shieldless projection optical system which projects multifunctional light beam through forming a virtual image in order to eliminate over-loss of flux, caused especially during low beam projection from an automobile.

Further, the present invention relates to an improved compact shieldless projection optical system that includes
- a plurality of light sources configured to produce light rays, wherein the light source is placed at overall focal point of optical system;
- a plurality of reflectors configured to receive light rays from the light source, wherein the reflector is placed at an angle with the light source to form a plurality of virtual images at its rear region; and
- a plurality of condenser lens having an input surface and an output surface, wherein the input surface of condenser lens is configured to receive light rays directed from the virtual image;
wherein the optical elements are placed in such a manner that second focal point of the reflector/s, focal point of the condenser lens and focal point of virtual image are formed at one common point that lies on the optical axis of the improved projection optical system.
In present invention, the improved projection optical system comprises optical elements such as light source, reflector, and condenser lens. Further, the light source provides light rays that falls onto inner reflective surface of reflector. The reflector forms reflected light rays and forms a virtual image at rear region of the reflector. Such virtual image acts as a virtual light source for condenser lens, wherein light rays are directed to produce virtual image. The directed light rays fall thereafter onto the condenser lens input surface and then output surface and finally forms the projected light beam which illuminates the road surface. Orientation of each optical elements is based on type of projected light beam that is required from the optical system. Further, the projection of multi-functional light beam is done through a switching mechanism.
The present invention further relates to a method of projecting low beam and/or high beam from the improved compact shieldless projection optical system which includes:
• arranging optical elements within the optical system in a pre-determined manner and orientation;
• next, producing light rays from the light source towards reflector’s inner reflective surface based on the requirement of low beam or high beam or both from the improved compact shieldless projection optical system;
• then, forming virtual image at rear region of the reflector by utilizing reflected pre-defined manner light rays as produced by reflector;
• next, light rays from virtual image is directed towards the input surface of the condenser lens based on low beam and/or high beam as required from the improved shieldless projection optical system;
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• Thereby, projecting low beam or high beam or both from the output surface of condenser lens of the improved compact shieldless projection optical system.
Advantageously, the improved compact shieldless projection optical system ensures that it requires less space for installation and simple in arrangement which is achieved due to formation of virtual images because of which there is considerable reduction in distance at which arrangement of the optical elements are placed. Due to this, resultant optical system is compact and much easy to install within an automobile.
Further, the arrangement of the optical elements in the improved compact shieldless projection optical system does not require shield for forming low beam. Due to elimination of the shield, fraction of reflected light rays will not be absorbed which will ensure elimination of over-loss of flux during forming of low beam. Additionally, the improved compact shieldless projection optical system will provide a clear image in the high beam. Furthermore, fog light and other types of light can be placed along with low beam and high beam optical arrangement according to requirement of the user.
The summary is provided to introduce the system as a representative concept in a simplified form that are further described below in the detailed description. This summary is not intended to limit the key essential features of the present invention nor its scope and application.
Other advantages and details about the system and the method will become more apparent to a person skilled in the art from the below detailed description of the invention when read in conjugation with the drawings.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Embodiments are described with reference to the following Figures. The same numbers may be used throughout to reference like features and components that are shown in the Figures:
Figure 1 illustrates a conventional optical system which is projecting low beam.
Figure 2 illustrates an isophotal graph of the projected low beam from the conventional optical system.
Figure 3 (a) illustrates the improved compact shieldless projection optical system to project low beam in accordance with an embodiment of the present invention.
Figure 3 (b) illustrates the improved compact shieldless projection optical system to project high beam in accordance with an embodiment of the present invention.
Figure 4 illustrates an isophotal graph of the projected low beam from the improved compact shieldless projection optical system in accordance with an embodiment of the present invention.
Figure 5 illustrates the improved compact shieldless projection optical system to project high beam or low beam or both in accordance with an embodiment of the present invention.
Figure 6(a) illustrates an isophotal graph of the projected high beam from the improved compact shieldless projection optical system in accordance with an embodiment of the present invention.
Figure 6(b) illustrates an isophotal graph of the projected low beam from the improved compact shieldless projection optical system in accordance with an embodiment of the present invention
Figure 6(c) illustrates an isophotal graph of the projected high beam and low beam from the improved compact shieldless projection optical system.
Figure 7 illustrates front view of the lens to depict arrangement of reflector to project low beam or high beam or fog lamp from the improved compact shieldless projection optical system.
Figure 8 illustrates front view of the lens to depict arrangement of reflector to project low beam or/and high beam from the improved compact shieldless projection optical system.
Figure 9 illustrates front view of the lens to depict arrangement of reflector to project low beam or/and high beam or/and fog lamp arranged from the improved compact shieldless projection optical system.
Fig 10 illustrates method steps to project low beam from the improved compact shieldless projection optical system in accordance with an embodiment of the present invention.
Fig 11 illustrates method steps to project high beam from the improved compact shieldless projection optical system in accordance with an embodiment of the present invention.
Figure 12 illustrates method steps to project high beam or low beam or both from the improved compact shieldless projection optical system in accordance with an embodiment of the present invention.
The present invention can be understood with reference to the detailed figures and description set forth herein. Various embodiments are discussed below with reference to the figures. However, those skilled in the art will readily appreciate that the detailed descriptions given herein with respect to the figures are simply for explanation of the invention as the methods and systems may extend beyond the described embodiments. For example, the teachings presented and the needs of a particular application yield multiple alternative and suitable approaches to implement the functionality of any detail described herein. Therefore, any approach extends beyond the particular implementation choices in the following embodiments described and shown.
References to “one embodiment,” “at least one embodiment,” “an embodiment,” “one example,” “an example,” “for example,” and so on indicate that the embodiment(s) or example(s) may include a particular feature, structure, circuit, architecture, characteristic, property, element, or limitation but that not every embodiment or example necessarily includes that particular feature, circuit, architecture, structure, characteristic, property, element, or limitation. Further, repeated use of the phrase “in an embodiment” does not necessarily refer to the same embodiment.
TERMS
Low beam is defined as a type of the light beam having lower intensity and is projecting light onto the surface to make nearby object visible to the user/driver.
High beam is defined as a type of the light beam having higher intensity and is projecting light in front of the vehicle to make distant objects visible to the user/driver.
Fog lamp is defined as a type of the light beam and is placed on the front of a vehicle to help user/drive to see objects with better visibility in fog.
Virtual image is defined as the image which cannot be obtained on a screen and is formed due to divergence of light after being reflected or refracted from a mirror, lens, or object.
Optical axis is defined as characteristic direction of the overall beam propagation through the improved compact shieldless projection optical system. Further, this line characterizes the designated direction parallel with the car driving direction.
Focal plane is defined as a plane where light source is placed or where image is created. The image created on this plane can be either a virtual image or a real image.
An isophotal graph is defined as a diagram showing light distribution in the angular space expressing the intensity either by some colour pallet or lines interconnecting places with the same intensity.
DESCRIPTION
The optical system is illustrated with various embodiments to depict orientation and arrangement of optical elements to project beam from such system. In Fig. 1, an illustration of a conventional optical system (100) is represented. The conventional optical system (100) comprises of a light source (101), a reflector (102), a shield (103) and a condenser lens (104).
The light source (101) is emitting light rays from it and is placed at an angle with respect to an optical axis (105) of the conventional optical system (100). The incident light rays from the light source (101) strikes onto the surface of the reflector (102). The reflector (102) in the conventional optical system (100) is elliptical in shape and is oriented perpendicularly with respect to the optical axis (105). The reflected light rays from the reflector (102) are guided towards the shield (103) to form a cut-off line in order to produce low beam. The shield (103) is located perpendicularly with the optical axis (105) of the conventional optical system (100). The optical axis (105) is defined horizontally passing through the mid-point of the light source (101), the reflector (102), the shield (103) and the condenser lens (104).
The shield (103) absorbs fraction of reflected light rays to form low beam from the conventional optical system (100). The reflected light rays from the reflector (102) forms an image (108) which is trim of the original image formed by the reflector (102). The image (108) is formed in the focal plane of the elliptical reflector (102) which coincide with a focal plane of the condenser lens (104). The directed light rays from the shield (103) falls onto the condenser lens (104). The condenser lens (104) project these light rays in the form of low beam and is used for illumination of near-by distance of road surface.
In Fig. 2 an isophotal graph (107) is illustrated for the low beam which is projected from the conventional optical system (100). The isophotal graph (107) has a cut off line with an elbow (107a) formed at a centre of the isophotal graph (107) and the formation of cut-off line is one of the characteristics of the low beam.
In the conventional optical system (100), due to the presence of the shield (103) a fraction of reflected light rays which are travelling from the reflector (102) are lost because the shield (103) is composed of a sheet metal or other non-transparent material which has a property of absorbing or reflecting light rays. In addition, absorption of fraction of reflected light rays causes over-loss of flux during low beam projection from the convention optical system (100).
Orientation and placing of shield (103) is required for forming cut-off line in low beam. Thus, such conventional system requires the shield without which low beam cannot be projected. Hence, this result into an increase in dimension of the optical elements used in the conventional optical system (100) because of which it requires a large space for its installation. Further, large dimension of the optical elements is caused by presence of considerable distance included in between optical elements. Due to this, conventional optical system (100) suffers is bulky. However, automobile such as two-wheeler, three-wheeler suffers from limitation of space. This causes difficulty in installing such system in two-wheeler.
Another major disadvantage of the conventional optical system (100) is that photometric efficiency of low beam considerably reduces because of over loss of flux. Hence, there is a need of an invention which tackles and addresses technical limitation of conventional optical system.
In order of effective solution, present invention is devised that overcomes and efficiently eliminates technical issue of conventional optical system.
Further, the present invention relates to an improved compact shieldless projection optical system that includes
- a plurality of light sources configured to produce light rays, wherein the light source is placed at overall focal point of optical system;
- a plurality of reflectors configured to receive light rays from the light source, wherein the reflector is placed at an angle with the light source to form a plurality of virtual images at its rear region; and
- a plurality of condenser lens having an input surface and an output surface, wherein the input surface of condenser lens is configured to receive light rays directed from the virtual image;
wherein the optical elements are placed in such a manner that second focal point of the reflector/s, focal point of the condenser lens and focal point of virtual image are formed at one common point that lies on the optical axis of the improved projection optical system.
In present invention, the improved projection optical system comprises optical elements such as light source, reflector, and condenser lens. Further, the light source provides light rays that falls onto inner reflective surface of reflector. The reflector forms reflected light rays and forms a virtual image at rear region of the reflector. Such virtual image acts as a virtual light source for condenser lens, wherein light rays are directed to produce virtual image. The directed light rays fall thereafter onto the condenser lens input surface and then output surface and finally forms the projected light beam which illuminates the road surface. Orientation of each optical elements is based on type of projected light beam that is required from the optical system. Further, the projection of multi-functional light beam is done through a switching mechanism.
In Fig. 3(a), an arrangement of the improved compact shieldless projection optical system (300) is illustrated which is used for projecting low beam. In an exemplary embodiment as shown by Fig. 3(a), the improved compact shieldless projection optical system (300)) comprises of a light source (301), a reflector (302) and a condenser lens (304) which is used in an automobile. In other embodiment, the present invention can be used for example in theatre screen, as a logo projection device in an automobile.
The light source (301) is oriented with respect to an overall focal point of the improved compact shieldless projection optical system (300). Further, light source (301) is configured to produce light rays towards the inner reflective surface of the reflector (302). In an embodiment, the number of light sources used may vary in accordance with the type of projected light beam from the required from improved compact shieldless projection optical system (300). Additionally, the orientation of the light source (301) is defined with respect to an optical axis (305) of the improved shieldless projection optical system (300). The optical axis (305) is an imaginary horizontal line which passes through the reflector (302) and the mid-point of the condenser lens (304). Preferably, the light source (301) is oriented perpendicularly (90 degree) with respect to the optical axis (305) of the improved compact shieldless projection optical system (300). In other embodiments, the orientation angle of the light source (301) with respect to the optical axis (305) may vary according to the type of the projected light beam from the improved optical system (300).
In illustrated Fig. 3(a), light source (301) is placed below the optical axis (305) in the improved shieldless projection optical system (300). The light source (301) used in the improved compact shieldless projection optical system (300) is not to be limited to any one kind and thus it may be of any shape and/or type.
The reflector (302) is placed at an angle to the light source (301) in a manner that first focal point of the reflector (302) coincides with the overall focal point of the improved shieldless projection optical system (300). Further, reflector (302) is configured to receive light rays from light source (301) and thus provides reflected light rays. The arrangement of the reflector (302) is with respect to projection of low beam from the improved compact shieldless projection optical system (300). In other embodiment, the arrangement of the reflector may vary in accordance with the type of the projected light beam from the improved compact shieldless projection optical system (300). Preferably, the number of reflectors used is one for projection of low beam from the improved compact shieldless projection optical system (300). In other embodiment,number of reflectors used may vary in accordance with the type of projected light beam from the improved compact shieldless projection optical system (300).
In one embodiment, the reflector (302) used in the improved compact shieldless projection optical system (300) is made up of metal. In other embodiment the material of the reflector (302) may vary in the improved compact shieldless projection optical system (300). The inner surface of the reflector (302) is coated/ metallized by high reflective material such as aluminium, silver chrome, stainless steel.
The reflector (302) in the improved compact shieldless projection optical system (300) forms a virtual image (303) through its reflected rays. The virtual image (303) is formed at a rear portion of the reflector (302) in such way that a second focal point of the reflector (302) coincides with a focal point (308) of the virtual image (303). The point of formation of virtual image (303) lies on the optical axis (305) of the improved shieldless projection optical system (300). The virtual image (303) is formed at pre-determined distance from light source (301), reflector (302), and condenser lens (304). This pre-determined distance is based on type of projected light beam as required from the improved shieldless projection optical system (300). Additionally, virtual image (303) acts as a virtual light source for the condenser lens (304). Further, the number of virtual image (303) formed is one for low beam projection from the improved shieldless projection optical system (300). Also, the number of virtual images formed may vary in accordance with the type of projected light beam from the improved compact shieldless projection optical system (300).
The condenser lens (304) has an input and an output surface, wherein the input surface of the condenser lens (304) faces the reflector (302) and the light source (301). The input surface (304a) of condenser lens is configured for receiving light rays directed from virtual image (303) and output surface (304b) provides a medium for light beam projection. Further, orientation of the condenser lens (304) is determined with respect to optical axis (305) of the improved shieldless projection optical system (300). At one of the instances, condenser lens (304) is orientated perpendicularly with respect to optical axis. The condenser lens (304) is placed at a pre-determined distance (307) from the light source (301) and reflector (302). The pre-determined condenser lens distance (307) is formed in such manner that second focal point of the reflector (302), focal point (308) of virtual image (303) and focal point of the condenser lens (304) lies at one common point on the optical axis (305) of the improved shieldless projection optical system (300). This pre-determined distance is also based on type of projected beam as required form the improved shieldless projection system (300).
The condenser lens (304) in the improved compact shieldless projection optical system (300) is composed of a material which have a low absorption for light rays in order to project a clear and a well-defined low beam having high photometric efficiency. In one embodiment, the condenser lens (304) is formed of a transparent glass. In other embodiment, the condenser lens (304) material may vary in accordance with the projected light beam from the improved compact shield-less projection optical system (300). The number of condenser lens used is one in the improved shieldless projection optical system (300). Accordingly, the number of condenser lens in the improved shieldless projection optical system (300) may vary in accordance with the projected low beam.
In Fig. 4, an isophotal graph (306) is illustrated with respect to a low beam which is projected from the improved compact shieldless projection optical system (300). Due to low beam formation, the isophotal graph (306) has an elbow (306a) at the centre. The formation of elbow in low beam represents presence of cut-off line. The cut-off line formation is one of the characteristics of the low beam. Further, elbow/cut-off line (306a) in low beam ensures that light beam is towards the road surface. Thus, making nearby objects lying on road clearly visible to an automobile user.
Figure 3 (b) illustrates an arrangement and orientation of the optical elements/ components of the improved compact shieldless optical system. In this embodiment, arrangement of optical elements is in a pre-determined order. In this order, orientation of reflector (302) is at pre-determined angle that forms a virtual image (303) at its rear portion. The virtual image (303) does not have cut-off line formed in it. Due to this arrangement, light rays as provided from virtual image (303) received by condenser lens (304). Thus, formation of high projection is possible from optical system (300).
A person skilled in the art will be able to implement all the embodiments of Fig. 3(a) (Illustrates the improved compact shield-less projection optical system used to produce low beam) for high beam as well. Therefore, Fig. 3(a) (low beam) is illustrated with only a few examples, it shall be equally applicable to incorporate the embodiments mentioned with respect to Fig. 3(b). Fig. 3(b) illustrates another exemplary embodiment of the subject matter of the present invention, which is used for projecting high beam from the improved compact shield-less projection optical system (300).
Fig. 10 illustrates steps of method (1000) for projecting low beam from the improved compact shieldless projection optical system (300) which includes -
? at step (1001), arranging optical elements in a pre-determined order and manner within an improved shieldless projection optical system. In this arrangement, light source (301) is placed at overall focal point of optical system (300). The reflector (302) is placed at an angle with the light source and is configured to receive light rays from light source. Also, orientation of reflector (302) with respect to light source (301) is done based on type of projected light beam as required from the system (300). Further, light source (301) and reflector (302) are also oriented with respect to optical axis (305) of the optical system (300). The orientation of reflector (302) is in such way that virtual image is formed at its rear region. Further, condenser lens (304) is placed at pre-determined distance (307) from light source (301) and reflector (302). This pre-determined distance (307) is based in such way that second focal point of reflector (302), focal point (308) of virtual image (303) and focal point of condenser lens (304) meets at one common point on optical axis (305) of the improved shieldless projection optical system (300);
? Then at step (1002), providing light rays from light source (301) towards the inner reflective surface of the reflector (302).During requirement of low beam, light rays are provided to reflector (302) in such manner that they are distributed asymmetrically. The reflector (302) forms reflected light rays that have asymmetrical distribution;
? Next, at step (1003), forming virtual image (303) at rear region of the reflector (302) by utilizing asymmetrically distributed reflected light rays of reflector (302). In furtherance of this, virtual image (303) acts as a virtual light source for condenser lens (304). The virtual light source produces directed light rays;
? Further, at step (1004), providing light rays directed from virtual light source in asymmetrical manner towards input surface of condenser lens (304a). The asymmetrical distributed directed light rays have presence of cut-off line in it. This asymmetrical distributed light rays proceeds and falls onto lower half of input surface of condenser lens (304a). Thereby, at step (1005), projecting low beam from the outer surface of condenser lens (304b). Further, projected low beam illuminates near-by distance of the road surface. Thus, resulting into visibility of near-by objects lying on road surface to a vehicle driver.
In the improved compact shieldless projection optical system (300) the light source (301) incident light rays onto the inner reflective surface of the reflector (302) to produce reflected rays. In an exemplary embodiment, the number of light sources used is one for low beam projected from the improved compact shieldless projection optical system (300). Accordingly, the number of light sources used may vary in accordance with the type of projected light beam from the improved compact shieldless projection optical system (300). The arrangement of the reflector (302) is with respect to low beam projected from the improved compact shieldless projection optical system (300). Accordingly, the arrangement of the reflector may vary in accordance with the type of the projected light beam from the improved compact shieldless projection optical system (300). Preferably, the number of reflectors used is one for low beam projection from the improved compact shieldless projection optical system (300). Further, the number of reflectors used may vary in accordance with the type of projected light beam from the improved compact shieldless projection optical system (300). The reflected rays from the reflector (302) forms a virtual image (303) at the rear point of the reflector (302). Preferably, the number of virtual image (303) formed is one for low beam projected from the improved compact shieldless projection optical system (300). However, the number of virtual image formed may vary in accordance with the type of projected light beam from the improved compact shieldless projection optical system (300). The formation of virtual image (303) is in such a manner that the focal point (308) of the virtual image (303) coincides with the second focal point of the reflector (302) on the optical axis (305) of the improved compact shieldless projection optical system (300).
The condenser lens (304) is placed in the improved compact shieldless projection optical system (300) at a pre-determined distance (307) from the reflector (302) in the manner that virtual image of the light source is formed at the focal point of the condenser lens (304). Thereby, focal point of the condenser lens (304), second focal point of the reflector (302) and focal point (308) of the virtual image (303) coincides at one common point on the optical axis (305) in the improved compact shieldless projection optical system (300). The number of condenser lens used is one in the improved compact shieldless projection optical system (300). Accordingly, the number of condenser lens in the improved compact shieldless projection optical system (300) may vary in accordance with the projected low beam.
The virtual image (303) act as a virtual light source for the condenser lens (304) from which light rays are directed onto the input surface of the condenser lens (304a) in a manner that it leads to formation of the final image at an infinity.
Further, projecting low beam from the output surface of the condenser lens (304b) from the improved compact shieldless projection optical system (300) through a switching mechanism.
A person skilled in the art will be able to implement all the steps as mentioned in Fig. 10 (Illustrates the improved compact shieldless projection optical system used to produce low beam) for high beam as well. Therefore, Fig. 10 (low beam) are illustrated with only a few examples, it shall be equally applicable to incorporate all the steps as mentioned in Fig. 11. In Fig. 11, steps (1100) of method are illustrated which can be followed to project high beam from the improved compact shieldless projection optical system (300).
Fig. 11 illustrates steps of method (1100) for projecting high beam from the improved compact shieldless projection optical system (300) which includes -
? at step (1101), arranging optical elements in a pre-determined order and manner within an improved shieldless projection optical system. In this arrangement, light source (301) is placed at overall focal point of optical system (300). The reflector (302) is placed at an angle with the light source and is configured to receive light rays from light source. Also, orientation of reflector (302) with respect to light source (301) is done based on type of projected light beam as required from the system (300). Further, light source (301) and reflector (302) are also oriented with respect to optical axis (305) of the optical system (300). The orientation of reflector (302) is in such way that virtual image (303) is formed at its rear region. Further, condenser lens (304) is placed at pre-determined distance (307) from light source (301) and reflector (302). This pre-determined distance (307) is based in such way that second focal point of reflector (302), focal point of virtual image (303) and focal point of condenser lens (304) meets at one common point on optical axis (305) of the improved shieldless projection optical system (300);
? then, at step (1102), providing light rays from light source (301) towards the inner reflective surface of the reflector (302). During requirement of high beam, light rays are provided to reflector (302) in such manner that they are distributed symmetrically. The reflector (302) forms reflected light rays that has symmetrical distribution.
? at step (1103), forming virtual image (303) at rear region of the reflector (302) by utilizing symmetrically distributed reflected light rays of reflector (302). In furtherance of this, virtual image (303) acts as a light source for condenser lens (304). The virtual light source produces directed light rays;
? Further, at step (1104), providing directed light rays from virtual light source in symmetrical manner towards input surface of condenser lens (304a). During high beam formation, intense and centre weighted distribution of directed light rays are required to fall onto input surface of condenser lens (304a). Alternatively, during forming high beam through optical system (300), light source from virtual image is provided at input surface of condenser lens (304), wherein whole input surface receives directed light rays.
Thereby, at step (1105), projecting high beam from the condenser lens output surface (304b). Further, projected high beam illuminates farther-off distance of road surface. Fig. 7 illustrates front view of the lens (701) to depict arrangement of a reflector (700) which is used for projecting low beam from the improved compact shieldless projection optical system (300). The lens (701) has a light source (703) and a reflector (702) inside it. The light source (703) emits light rays which falls onto the surface of reflector (702). The reflector (702) is placed and arranged inside the lens perimeter (701) with respect to the required type of projected light beam pattern from the improved compact shieldless projection optical system (300). As illustrated in Fig. 7, arrangement of the reflector (702) and light source (703) can be used for low beam projection from the improved compact shieldless projection optical system (300). Alternatively, in another embodiment, arrangement of reflector and light source can be altered in the lens for projection of different type of light beam such as high beam, fog lamp/beam, and so on.
A person skilled in the art will be able to implement all the embodiments of Fig. 3(a) and 3(b) for projecting different type of light beams as well. Therefore, altghough Fig. 3(a) and 3(b) (low beam and high beam respectively) are illustrated with only a few examples, it shall be equally applicable to incorporate the embodiments as mentioned and disclosed in Fig. 5.
In Fig. 5, an exemplary embodiment of arrangement of optical elements is illustrated for the improved compact shieldless projection optical system (500) for projecting high beam and/or low beam. Further, improved compact shieldless projection optical system (500) can be used for projecting combination of fog light and low beam. Alternatively, there can be other combination as well for which improved optical system is used.
The improved compact shieldless projection optical system (500) comprises of plurality of the light sources (501a, 501b), plurality of the reflectors (502a, 502b), and plurality of the condenser lens (504).
The light sources (501a, 501b) are oriented with respect to the overall focal point of the improved compact shieldless projection optical system (500). Preferably, the number of light sources used are two for projecting low beam and/or high beam from the improved compact shieldless projection optical system (500). The orientation of the light sources (501a, 501b) are defined with respect to an optical axis (505) of the improved compact shieldless projection optical system (500). The optical axis (505) is an imaginary horizontal line which passes through the reflectors (502a, 502b) and of the condenser lens (504). Preferably, the light sources (501a, 501b) are oriented perpendicularly (90 degree) with respect to the optical axis (505) of the improved compact shieldless projection optical system (500). In other embodiments, the orientation angle of light sources (501a, 501b) with respect to the optical axis (505) may vary according to the type of the projected light beam from the improved compact shieldless projection optical system (500).
The first light source (501a) is placed above the optical axis (505) while the second light source (501b) is placed below the optical axis (505) in the improved compact shieldless projection optical system (500). The light sources (501a, 501b) used in the improved compact shieldless projection optical system (500) is not to be limited to any one kind, thus, it can be of any shape and type.
The reflectors (502a, 502b) are placed at an angle to the light sources (501a, 501b) in such a manner so that the first focal point of the plurality of the reflectors (502a, 502b) coincides with the overall focal point of the improved compact shieldless projection optical system (500). Further, reflectors (502a, 502b) is arranged based on low beam or high beam or both as required from the improved compact shieldless projection optical system (500). In addition, arrangement of reflectors may vary in accordance with the type of projected light beam from the improved compact shieldless projection optical system (500). In an exemplary embodiment the number of reflectors used are two for low beam or high beam or both projected from the improved compact shieldless projection optical system (500). The first reflector (502a) is placed above the optical axis (505) and is oriented at an angle with the first light source (501a). The second reflector (502b) is placed below the optical axis (505) and is oriented at angle with the second light source (501b). Further, the first reflector (502a) is placed such that one of its ends is in contact with one of the ends of the second reflector (502b) to avoid interference of light beam. This is done in a manner that reflectors (502a and 502b) point of contact is formed on the optical axis (505) in the improved shieldless projection optical system (500).
The reflectors (502a, 502b) in the improved compact shieldless projection optical system (500) forms virtual images (503a, 503b) through its reflected rays. Preferably, the number of virtual images formed are two for high beam or low beam or both projected from the improved compact shieldless projection optical system (300). The first reflector (502a) forms a first virtual image (503a) while the second reflector (502b) forms a second virtual image (503b). These virtual images (503a, 503b) is formed at a rear portion of the e reflectors (502a, 502b). The point of formation of virtual images (503a, 503b) coincides with the second focal point of the reflectors (502a, 502b). The virtual image (503a, 503b) is formed at pre-determined distance from light source (501a, 501b), reflector (502a, 502b), and condenser lens (504). This pre-determined distance is based on type of projected light beam as required from the improved shieldless projection optical system (500). The virtual images (503a, 503b) act as a virtual light source for the condenser lens (504) in the improved compact shieldless projection optical system (500).
The condenser lens (504) has an input surface (504a) and an output surface (504b), wherein the input surface (504a) faces light sources (501a, 501b) and reflectors (502a, 502b). The condenser lens (504) is placed at a pre-determined distance (507) from the light source (501a, 501b) and plurality of the reflectors (502a, 502b). This ensures that the second focal point of plurality of the reflectors (502a, 502b), focal point (508) of virtual images (503a, 503b) and focal point of the condenser lens (504) lies on the optical axis (505) of the improved compact shieldless optical system (500).
In Fig. 6(a), an isophotal graph (506) is illustrated for the projected high beam from the improved compact shield-less projection optical system (500). In the isophotal graph (506), the curve (506a) formed is uniformly and systematically distributed around the centre and along the horizontal as well as vertical axis. The uniform and symmetrical distribution of the curve (506a) in the isophotal graph (506) is a property of the high beam.
In Fig. 6(b), an isophotal graph (506) is illustrated for the projected low beam (506b) from the improved compact shieldless projection optical system (500). In the isophoptal graph, an elbow (506c) is formed at the centre of the graph, that represents presence of cut-off line. Further, isophotal graph in fig 6(b) represents asymmetrical distribution of light beam that is one of the characteristics of low beam.
In Fig. 6(c), an isophotal graph (506) is illustrated for the projected low beam (506b) and high beam (506a) from the improved compact shieldless projection optical system (500). In the isophotal graph (506), the upper half of the graph shows the projection of high beam (506a) and the lower half of the graph shows the projection of the low beam (506b). The low beam has elbow/cut-off line (506c) in it which is an important characteristic of such beam.
Fig. 12 illustrates steps of method (1200) for projecting low beam or high beam or both from the improved compact shield-less projection optical system (500) which includes:
? at step (1201), arranging and placing optical elements within improved shieldless projection optical system. In this arrangement, light sources (501a, 501b) are arranged at overall focal point of the system (500). Further, reflectors (502a, 502b) are placed at an angle with light sources (501a, 501b) and are configured to receive light rays from light sources (501a, 501b). Orientation of light sources (501a, 501b) and reflectors (502a, 502b) is based on optical axis (505) of the improved shieldless projection system (500). The orientation of reflectors (502a, 502b) is with respect to light sources (501a, 501b) and is based on type of projected light beam required from the system (500). The orientation of reflectors (502a, 502b) is in such way that virtual images (503a, 503b) are formed at its rear region. Further, condenser lens (504) is placed at pre-determined distance (507) from light sources (501a, 501b) and reflectors (502a, 502b). This pre-determined distance (507) is based in such way that second focal point of reflectors (502a, 502b), focal point of virtual images (503a, 503b) and focal point of condenser lens (504) meets at one common point on optical axis (505) of the improved shieldless projection optical system (500);
? at step (1202), providing incident light rays from light sources (501a, 501b) towards the inner reflective surface of reflectors (502a, 502b) based on type of light beam required from the improved shieldless projection optical system (500). During requirement of low beam, asymmetrical distribution of light rays is required while light rays are falling onto inner reflective surface of first reflector (502a). On the other hand, during high beam requirement, symmetrical distribution of light rays is required while light rays are falling onto inner reflective surface of second reflector (502b);
? at step (1203), forming virtual images (503a, 503b) at rear region of reflectors (502a, 502b) by utilizing asymmetrical and symmetrical distributed reflected light rays from reflectors (502a, 502b). In furtherance of this, virtual images (503a, 503b) acts as virtual light sources for condenser lens (504).
? at step (1204), providing light rays directed from virtual light sources in asymmetrical and symmetrical manner towards input surface of condenser lens (504a). The asymmetrical distributed directed light rays have presence of cut-off line in it. The symmetrical distributed light rays is intense and focused in nature;
? at step (1205), thereby, projecting low beam or high beam or both from the output surface of condenser lens (504b) of improved compact shieldless projection optical system (500). This projection of low beam and/or high beam is done by a vehicle driver through a switching mechanism. Further, projected low beam and/or high beam illuminates road surface in accordance with their characteristics.
Thus, in accordance with one embodiment of the present invention the first light source (501a) and the second light source (502a) incident light rays onto the first reflector (502a) and the second reflector (502b) respectively in order to produce reflected rays. Preferably, the number of light sources is two for low beam or high beam or both projected from the improved compact shieldless projection optical system (500). In other embodiment the number of the light source may vary in accordance with the projected light beam from the improved compact projection optical system (500).
The reflectors (502a, 502b) are arranged in accordance with low beam or high beam or both projected from the improved compact shieldless projection optical system (500). Preferably, the arrangement of the reflectors may vary in accordance with the type of projected light beam from the improved compact shieldless projection optical system (500). In one embodiment, reflectors (502a, 502b) in the improved compact shieldless projection optical system (500) are made up of metal. In other embodiment the material of reflectors (502a, 502b) may vary.
The reflected rays from the first reflector (502a) forms a first virtual image (503a) and the reflected rays from the second reflector (502a) forms a second virtual image (503b) at the rear portion of the respective reflectors (502a, 502b). In an exemplary embodiment, the number of virtual images (503a, 503b) formed are two for low beam or high beam or both projected from the improved compact shieldless projection optical system (500). Accordingly, the number of virtual images may vary according to the type of projected light beam from the improved compact shieldless projection optical system (500). The formation of virtual images (503a, 503b) is formed in such a way that focal point (508) of virtual images (503a, 503b) coincides with second focal point of reflectors (502a, 502b) on the optical axis (505) of the improved optical system (500).
Further, the condenser lens is placed at a pre-determined distance (507) from plurality of the reflectors (502a, 502b) in a manner that focal point (508) of plurality of the virtual images (503a, 503b) coincides with the focal point of the condenser lens (504). This ensures that the focal point of the condenser lens (504), second focal point of the reflectors (502a, 502b) and focal point (508) of the virtual images (503a, 503b) coincides on the optical axis (505) of the improved compact shieldless projection optical system (500). The number of condenser lens used is one in the improved compact shieldless projection optical system (500). Accordingly, the number of condenser lens in the improved compact shieldless projection optical system (500) may vary in accordance with the projected low beam or high beam or for both.
The virtual images (503a, 503b) act as a virtual light source for the condenser lens (504). The directed rays from the focal point (508) of the virtual images (503a, 503b) fall onto the input surface of the condenser lens (504a) which further leads to formation of the final image at an infinity.
Projecting low beam or high beam or both from the output surface of the condenser lens (504b) to an infinity in an outward direction from the improved compact shieldless projection optical system (500) through a switching mechanism.
Fig. 8 and Fig. 9 illustrates different arrangement of reflectors (800, 900) which can be used in the improved compact shieldless projection optical system (500). These reflectors can project light beam which is combination of different type of beam.
In Fig. 8 illustrates front view of the lens (801) to depict arrangement of a reflectors to produce low beam and/or high beam from the improved compact shieldless projection optical system (500). There are two light sources (802a, 802b) for low beam and high beam respectively in the lens (801). The light rays from the light sources (802a, 802b) falls onto the surface of reflectors (803a, 803b). Further, reflectors (803a, 803b) are placed adjacent to each other inside the lens (801). The first reflector (803a) is used for low beam while the second reflector is used for high beam (803b) respectively. The reflectors are placed and arranged inside the lens (801) perimeter in accordance with the type of projected light beam pattern from the improved compact shieldless projection optical system (500).
In Fig. 9, another embodiment of the lens (901) is illustrated for the arrangement of reflectors (900) to produce low beam or high beam or fog lamp from the improved compact shieldless projection optical system (500). There are three light sources (902a, 902b, 902c) for high beam booster, fog lamp and low beam respectively inside the lens (901). The light rays from the light sources (902a, 902b, 902c) falls onto the reflectors (903a, 903b, 903c) which are placed adjacent to each other inside the lens (901). The first reflector (903a) is used for high beam booster, the second reflector (903b) is used for fog lamp and third reflector (903c) is used for low beam respectively. The reflectors are placed and arranged inside the lens (901) perimeter in accordance with the type of projected light beam pattern from the improved compact shieldless projection optical system (500).
Examples
The embodiments of this invention are further explained by way of following examples. However, the examples do not limit the scope of the invention claimed in any manner. The invention can be implemented through other embodiments having different dimensions of the elements based on the requirements of the improved compact shieldless projection optical system (300, 500).
Example 1: In an exemplary embodiment with respect to improved compact shieldless projection optical system (300, 500) used for projecting multifunctional light beam following dimensions can be considered:
The radius of the condenser lens (304, 504) in the improved compact shieldless projection optical system (300, 500) preferably lies in the range of 30-70mm.
The angle of orientation of the light source (301, 501a, 501b) with respect to the reflector (302, 502a, 502b) in the improved compact shieldless projection optical system (300, 500) preferably lies in the range of 60-120 degree.
The thickness of the condenser lens (304, 504) in the improved compact shieldless projection optical system (300, 500) preferably lies in the range of 5-40mm.
The overall size of the improved compact shieldless projection optical system (300, 500) preferably lies in the range of 0-70mm.
The distance at which light source (301, 501a, 501b) is placed from the condenser lens (304, 504) in the improved compact shieldless projection optical system (300, 500) preferably lies in the range of 0-70mm.
Advantageously, there is a significant and substantial improvement of the present invention for reducing dimension of the optical elements in order to reduce space for their installation especially in two-wheeler and three-wheeler. The improved compact shieldless projection optical system (300, 500) can form plurality of the virtual images (303, 503a, 503b) from which light beam is formed. Due to formation of virtual images (303, 503a, 503b), it is ensured that directed light rays from the focal point (308, 508) of virtual images (303, 503a, 503b) to the condenser lens (304, 504) is coming from a far-off distance. This enables assurance towards maintaining photometric efficiency of projected light beam. Thus, enabling a clear and a well-defined image.
Due to formation of plurality of the virtual images (303, 503a, 503b) the pre-determined distance (507, 307) at which condenser lens is placed (304, 504) from plurality of the reflectors (302, 502a, 502b) is reduced. In addition, the dimension of plurality of the reflectors (302, 502a, 502b) and the condenser lens (304, 504) is also reduced thus reducing the overall size of the improved compact shieldless projection optical system (300, 500).
Due to reduction in dimension of plurality of the reflectors (302, 502a, 502b) and the condenser lens (304, 504) the space requirement for installing the improved compact shieldless projection optical system (300, 500) in an automobile reduces. This is particularly beneficial for two-wheeler, three-wheeler, four-wheeler etc. Since the overall size of the improved compact shieldless projection optical system (300, 500) is reduced hence there will be a reduction in weight of an automobile.
The improved compact shieldless projection optical system (300, 500) has arranged optical elements in such a manner that low beam is formed without usage of the shield. This will eliminate over-loss of flux and will further improve photometric efficiency with respect to the low beam.
A description of an embodiment with several components in communication with each other does not imply that all such components are required. On the contrary, a variety of optional components are described to illustrate the wide variety of possible embodiments of the invention. In furtherance of this, mentioned or disclosed optical elements are in no way to be considered as limitation and may include several additional optical elements to achieve objective as stated in present invention.
A person with ordinary skills in the art will appreciate that the systems, circuit elements, modules, and sub-modules have been illustrated and explained to serve as examples and should not be considered limiting in any manner. It will be further appreciated that the variants of the above disclosed circuit elements, modules, and other features and functions, or alternatives thereof, may be combined to create other different systems or applications.

While the present disclosure has been described with reference to certain embodiments and exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the present disclosure without departing from its scope.
,CLAIMS:We Claim:
1. An improved compact shieldless projection optical system (300, 500) having optical elements for projecting multifunctional light beam comprising:

• a plurality of light source (301, 501a, 501b) configured to produce light rays, wherein the light source (301, 501a, 501b) is placed at an overall focal point of the optical system (300, 500);
• a plurality of reflectors (302, 502a, 502b) with an inner reflective surface configured to receive light rays from the light source (301, 501a, 501b), wherein the reflector (302, 502a, 502b) is placed at an angle with the light source (301, 501a, 501b) to form a plurality of virtual images (303, 503a, 503b) at its rear region; and
• a plurality of condenser lens (304, 504) having an input surface (304a, 504a) and output surface (304b, 504b), wherein the input surface of condenser lens (304a, 504a) is configured to receive reflected light rays from the reflector (302, 502a, 502b);

wherein the optical elements are placed in such a manner that second focal point of the reflector (302, 502a, 502b), focal point (308, 508) of virtual images (303, 503a, 503b) and focal point of the condenser lens (304, 504) are formed at one common point that lies on an optical axis (305, 505) of the improved projection optical system (300, 500).

2. The improved optical system as claimed in claim 1, wherein orientation of light source (301, 501a, 501b), reflector (302, 502a, 502b) and condenser lens (304, 504) is based on the optical axis (305, 505) of the optical system (300, 500).

3. The improved optical system as claimed in claim 1, wherein first focal point of reflector (302, 502a, 502b) coincides with the overall focal point of the optical system (300, 500).

4. The improved optical system as claimed in claim 1, wherein the virtual image (303, 503a, 503b) acts as virtual light source for the condenser lens (304, 504).

5. The improved optical system as claimed in claim 1, wherein the input surface of the condenser lens (304a, 504a) face towards the light source (301, 501a, 501b), and reflector (302, 502a, 502b) and the output surface of the condenser lens (304b, 504b) projects light beam.

6. The improved optical system as claimed in claim 1, wherein the condenser lens (304, 504) is arranged at a pre-determined distance from the reflector (302, 502a, 502b) and the light source (302, 502a, 502b).

7. The improved optical system as claimed in claim 6, wherein the pre-determined distance (307, 507) for placing condenser lens (304, 504) is based on type of projected beam required from the optical system (300, 500).

8. A method for projecting light beam from the improved compact shieldless projection optical system (300,500), the method includes steps:

• arranging optical elements in a pre-determined order and manner within an improved shieldless projection optical system (300, 500);
• providing light rays from light source (301, 501a, 501b) towards inner reflective surface of reflector (302, 502a, 502b);
• forming virtual image (303, 503a, 503b) at rear region of the reflector (302, 502a, 502b) by utilizing predefined manner distributed light rays of the reflector (302, 502a, 502b);
• providing directed light rays in predefined manner from virtual light source (303, 503a, 503b) towards input surface of condenser lens (304a, 504a); and
• projecting light beam from outer surface of condenser lens (304b, 504b).
9. The method of projecting light beam from the improved compact shieldless projection optical system as claimed in claim 8, wherein the light beam can be multifunctional light beam.

10. The method of projecting beam from the improved compact shieldless projection optical system as claimed in claim 9, wherein the multifunctional beam can be low beam or high beam or both.

11. The method of projecting beam from the improved compact shieldless projection optical system as claimed in claim 8, wherein the predefined manner of reflected light rays is asymmetrical or symmetrical.

12. The method of projecting beam from the improved compact shieldless projection optical system as claimed in claim 11, wherein the asymmetrical reflected light rays is a characteristic of low beam that has presence of cut-off line and has broad beam to illuminate wider angle of road surface.

13. The method of projecting beam from the improved compact shieldless projection optical system as claimed in claim 11, wherein the symmetrical reflected light rays is a characteristic of high beam that is intense and has narrow beam to illuminate longer distance of road surface.

Dated this September 17, 2022.

Archana Singh, Vivek Ranjan, Shreya Chaudhary
(IN/PA-1936, IN/PA-3170, IN/PA-5145)
Of Singh and Singh Law Firm LLP
Patent Agents for the Applicant