Description:TECHNICAL FIELD
[0001] The present disclosure, in general, relates to an automotive exterior lamp. More particularly, it relates to an automotive exterior lamp with a Lambertian LED light source and a segmented freeform optic element to achieve desired photometry pattern.

BACKGROUND
[0002] Background description includes information that may be useful in understanding the present disclosure. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed disclosure, or that any publication specifically or implicitly referenced is prior art.
[0003] Lighting devices must adhere to a number of intricate regulations in the field of illumination technology for cars. Light-emitting diodes (LEDs) have increased in popularity in recent years and are now frequently used in several automotive lighting applications. LEDs are a good choice for automotive applications since they consume less power compared to other light sources used, last longer, and produce less heat than outdated incandescent bulbs.
[0004] Existing lighting devices for automobiles available in the market based on reflectors and conventional collimator concepts have low optical efficiency. The reflector and collimator-based systems have an optical efficiency in the range of 30-50% depending on their size. The efficiency of the reflector-based systems reduces exponentially with decrease in the reflector size. There is a need for high-efficiency designs to realize the automotive lighting functions, which can lead to decrease in the required LED power. The conventional collimators require additional optics to achieve specific light patterns. The size and cost of the optical system increase due to the additional optics or elements. Also, small lit opening systems are difficult to realize with reflectors.
[0005] Efforts have been made in the past to provide solutions to the above-mentioned problems. Patent document CN208779371 discloses optical structure that achieves rear fog distribution using a freeform optical lens characterized as a function of ratio of length and width of light entering surface as well as the ratio of length and width of the light emitting surface. As mentioned in the art, it needs to maintain a specific ratio of length and width of the light entering surface and light-emitting surface. However, it limits freedom to design systems to meet different styling lit opening requirements without a deterioration in optical efficiency.
[0006] Patent document CN217004298 discloses an automobile rear fog lamp with an LED light source and a lens (light concentrating structure) where the lens is having diffusion pattern on the light exiting surface (outer surface of light concentrating structure). The diffusion pattern has horizontal pattern structure and vertical pattern structure arranged alternatively in different combinations to achieve the rear fog distribution. This prior art is having additional optics to get the desired beam pattern where the collection optics and distribution optics are different. However, additional diffusion pattern on lens will add additional processes in tooling and increases the manufacturing cost.
[0007] Patent document CN114636135 discloses a rear fog module structure that consists of collection optics (light incident lampshade) and distribution optics (light emitting lampshade). Polygonal patterns are employed in light emitting lampshades to achieve the rear fog distribution. Rhombus pattern structures are used on the inner surface of the lampshade and hexagonal array structures are used on the outer surface of the lampshade to achieve the rear fog pattern. Additional optics or elements are employed to achieve the rear fog distribution, which leads to an increase in the size, number of components, and results in increased package size and cost. As there are multiple optical elements involved to achieve the light pattern, there might be more light loss.
[0008] Patent document US8011803B2 discloses an automotive front fog using 7 assemblies of normal collimating lens with Lambertian LED encompassing collimating surface including TIR surface and corrugated surface attached to collimating surface at an acute angle with respect to the optics axis of collimating surface. The normal collimator consists of collimating lens and collimating surface as collection optics. The corrugated surface acts as the distribution optics, which define the beam pattern. However, output light pattern is limited to front fog photometry distribution only. As the collection optics and distribution optics are different, system complexity and manufacturing cost will increase.
[0009] Patent document US8733992B2 describes a TIR based lens with a light baffle and a anamorphic lens is used to achieve desired light distribution for front fog photometry. The collection optics (TIR lens) collects the light from the light source and converges to the focus of the anamorphic lens (distribution optics). The converging beam from the TIR lens passes through the aperture of light baffle and then it is distributed by the anamorphic lens to get the front fog pattern. The use of additional optical elements with primary optics will increase the package size and number of components and will increase the system cost.
[0010] The referred patent documents teach different designs of lamps for automotive lighting functions and do not provide an efficient solution to the above-mentioned problems.
[0011] There is, therefore, a need to overcome the above drawbacks, limitations, and shortcomings associated with the existing automotive lamp techniques by providing a solution to achieve desired light distribution by reducing size of optical element and reducing the number of optical components used in the automotive exterior lamp.

OBJECTS OF THE PRESENT DISCLOSURE
[0012] Some of the objects of the present disclosure, which at least one embodiment herein satisfy are as listed herein below.
[0013] A general object of present disclosure is to overcome the above drawbacks, limitations, and shortcomings associated with the existing lamp for automotive lighting functions, by providing an automotive lamp to achieve desired light distribution.
[0014] Another object of the present disclosure is to provide an automotive lamp that has high optical efficiency. The high efficiency reduces input LED luminous flux requirements that tend to reduction in power requirements, and reduction in power enhances thermal stability and cost-effectiveness.
[0015] Another object of the present disclosure is to provide an automotive lamp where light collection optics and light distribution optics are same.
[0016] Another object of the present disclosure is to provide an automotive lamp that eliminates the need for additional optics thus reducing size of optical element used and saving additional manufacturing costs of additional optic elements.
[0017] Another object of the present disclosure is to provide an automotive lamp that is lighter in weight, as it is smaller in size and uses the same component as light collection and distribution optics compared to traditional automotive lamps.
[0018] Another object of the present disclosure is to provide an automotive lamp that generates symmetric or asymmetric beam patterns for automotive lighting functions.
[0019] Another object of the present disclosure is to provide an automotive lamp that generates symmetric beam patterns such that they can be used in both LH and RH sides of vehicle.
[0020] Another object of the present disclosure is to provide an automotive lamp that is used with Lambertian LED light source, where photometry requirement is to be met with small package size and less number of parts with high optical efficiency.

SUMMARY
[0021] Various aspects of present disclosure relate to an automotive exterior lamp. More particularly, it relates to an automotive exterior lamp with a Lambertian LED light source and a segmented freeform optic element to achieve desired photometry pattern. The automotive lamp with a Lambertian LED light source and a segmented freeform optic element (i.e., segmented freeform lens) is disclosed that uses latest in LED and lens technology to produce a specific photometry pattern. The use of LED lights as light source provides numerous benefits over traditional lighting sources, including increased energy efficiency, longer lifespan, and better durability. The Lambertian LED light source provides an angular equally bright output in the light emitting cone, which is ideal for automotive lighting applications where a consistent and specific photometry pattern is required.
[0022] In an aspect, the segmented freeform optic element may be optically connected to the light source, and the segmented freeform optic element includes a plurality of surfaces configured to collect the light beam from the light source on each of the plurality of surfaces and combinedly generate photometry pattern corresponding to the desired automotive lighting function.
[0023] In an aspect, the segmented freeform optic element includes a freeform center refracting surface, segmented side refracting surfaces, segmented freeform total internal reflecting (TIR) surfaces, and a light exiting surface.
[0024] In an aspect, the freeform center refracting surface may be positioned at a pre-defined height from the light source and configured to refract the received light beam from the light source. In another aspect, the one or more (segmented) side refracting surfaces standing substantially connected to one or more edges of the freeform center refracting surface, such that all side refracting surfaces are connected to the periphery of freeform center refracting surface, and the segmented side refracting surfaces may be configured to refract the light beam received from the light source. In yet another aspect, the one or more (segmented) freeform TIR surfaces may be connected to one end of each of the one or more side refracting surfaces and configured to facilitate total internal reflection (TIR) from the received refracted light beam from side refracting surfaces. Furthermore, the segmented TIR surfaces are used to collect and distribute the light to generate desired photometry pattern
[0025] In an aspect, the segmented freeform optic element generates the photometry pattern of any of rear fog lamp, warning lamp (Category X), and combination of front fog lamp and corner lamp, corresponding to their associated regulations including ECE R38, R65, R19, and R119 respectively.
[0026] In an aspect, the light exiting surface may be positioned at a front end of the segmented freeform optic element, and the light exiting surface may be configured to generate the photometry pattern from the refracted beam, received from the freeform center refracting surface, and the reflected light beam, received from the segmented freeform total internal reflecting surfaces.
[0027] The segmented freeform lens is designed to shape and direct the light output from the LED source to create the desired photometry pattern. This type of lens is made up of multiple segments, each with its own specific shape and curvature, that work together to produce the desired lighting effect. This advanced lens technology allows for a greater degree of control over the light output, enabling the automotive lamp to produce more customized, precise and accurate photometry patterns.
[0028] Various objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like features.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0029] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure. The diagrams are for illustration only, which thus is not a limitation of the present disclosure.
[0030] FIG. 1 illustrates a sectional view of an automotive lamp, including a segmented freeform optic element positioned over an LED light source, in accordance with an embodiment of the present disclosure.
[0031] FIG. 2 illustrates an exemplary perspective view of an automotive lamp when light beam emitted from a light source hit on a freeform center refracting surface, in accordance with an embodiment of the present disclosure.
[0032] FIG. 3 illustrates an exemplary perspective view of an automotive lamp when light beam emitted from a light source hit on a side refracting surface, in accordance with an embodiment of the present disclosure.
[0033] FIG. 4 illustrates an exemplary isometric view of a segmented freeform optic element of automotive lamp for rear fog function, in accordance with an embodiment of the present disclosure.
[0034] FIG. 5 illustrates an exemplary front view of a segmented freeform optic element of automotive lamp for rear fog function, in accordance with an embodiment of the present disclosure.
[0035] FIG. 6 illustrates exemplary four segments of freeform TIR surfaces of a segmented freeform optic element for rear fog lamp, in accordance with an embodiment of the present disclosure.
[0036] FIG. 7 illustrates an exemplary isometric view of a segmented freeform optic element for front fog and corner lamp, in accordance with an embodiment of the present disclosure.
[0037] FIG. 8 illustrates an exemplary front view of a segmented freeform optic element for front fog and corner lamp, in accordance with an embodiment of the present disclosure.
[0038] FIG. 9 depicts exemplary eight segments of freeform TIR surfaces of a segmented freeform optic element for front fog and corner lamp, in accordance with an embodiment of the present disclosure.
[0039] FIG. 10 illustrates rear fog lamp photometry pattern achieved with proposed automotive lamp, in accordance with an embodiment of the present disclosure.
[0040] FIG. 11 illustrates a warning lamp (Category X) photometry pattern achieved with the proposed automotive lamp, in accordance with an embodiment of the present disclosure.
[0041] FIG. 12 illustrates a front fog and corner lamp photometry pattern achieved with proposed automotive lamp, in accordance with an embodiment of the present disclosure.
[0042] FIG. 13 illustrates an asymmetrical photometry pattern of front fog and corner lamp for right-hand side lamp, in accordance with an embodiment of the present disclosure.
[0043] FIGs. 14A and 14B illustrate exemplary perspective views for multiple segmented freeform optic elements assembled together for output light distributions, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0044] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims. Embodiments of present disclosure relates to an automotive lamp. More particularly, it relates to an automotive lamp with a Lambertian LED light source and a segmented freeform optic element to achieve desired photometry pattern.
[0045] In an embodiment, the automotive lamp with a Lambertian LED light source and a segmented freeform optic element (i.e., segmented freeform lens) is disclosed that uses latest in LED and lens technology to produce a specific photometry pattern. In an aspect, the segmented freeform optic element is optically connected to the light source, and the segmented freeform optic element includes a plurality of surfaces configured to collect the light beam from the light source on each of the plurality of surfaces and combinedly generate photometry pattern corresponding to the automotive lighting function.
[0046] In an embodiment, the segmented freeform optic element includes a freeform center refracting surface, segmented side refracting surfaces, segmented freeform total internal reflecting (TIR) surfaces, and a light exiting surface.
[0047] In an embodiment, the freeform center refracting surface may be positioned at a pre-defined height from the light source and configured to refract the received light beam from the light source. In another embodiment, the one or more (segmented) side refracting surfaces standing substantially connected from all the four edges of the freeform center refracting surface, and the segmented side refracting surfaces may be configured to refract the light beam received from the light source. In yet another embodiment, the one or more (segmented) freeform TIR surfaces may be connected to one end of each of the one or more side refracting surfaces, and the TIR surfaces include a freeform profile and shape and are configured to facilitate total internal reflection (TIR) from the received refracted light beam.
[0048] In an embodiment, the light exiting surface may be positioned at a front end of the segmented freeform optic element, and the light exiting surface may be configured to generate the desired photometry pattern from the refracted beam, received from the freeform center refracting surface, and the reflected light beam, received from the segmented freeform total internal reflecting surfaces.
[0049] FIG. 1 illustrates a sectional view of an automotive lamp for a motor vehicle, in accordance with an embodiment of the present disclosure.
[0050] As illustrated, an automotive lamp 100 for a motor vehicle is disclosed. The motor vehicle can be a car, bus, truck, van, two-wheeler, or the like. The automotive lamp 100 can be such as but not limited to, rear fog lamp, warning lamp, front fog lamp, corner lamp, or the likes. In an exemplary embodiment, the automotive lamp 100 basically includes a casing which is preferably made of plastic material and is preferably structured so as to be at least partially recessed into front or rear part of the motor vehicle and is provided with one or more transparent or semi-transparent, optionally also colored, areas/portions.
[0051] Automotive lamp 100 includes a light source 102 i.e. a Lambertian LED light source and configured to generate a light beam, and a segmented freeform optic element 104 (interchangeably referred to as segmented freeform lens, hereinafter) optically connected to the light source 102, where the segmented freeform optic element 104 may be configured to generate symmetrical or asymmetrical photometry light distribution. Additionally, the segmented freeform optic element 104 generates the photometry pattern of any of rear fog lamp, warning lamp (Category X), and combination of front fog and corner lamps, corresponding to their associated regulations such as ECE R38, R65, R19, and R119 respectively. Further, the segmented freeform optic element 104 includes a plurality of surfaces configured to collect the light beam from the light source on each of the plurality of surfaces and combinedly generate desired photometry pattern corresponding to type of the automotive lighting function to be activated.
[0052] In an embodiment, the segmented freeform optic element 104 includes a freeform center refracting surface 106 (interchangeably referred to as first refracting surface 106, hereinafter), segmented side refracting surfaces 108 (interchangeably referred to as one or more second refracting surfaces 108, hereinafter), segmented freeform total internal reflecting (TIR) surfaces 110 (interchangeably referred to as one or more third reflecting surfaces, 110, hereinafter), light exiting surface 112 (interchangeably referred to as fourth surface 112, hereinafter). The freeform center refracting surface 106 is having convex or concave shape. Additionally, the freeform center refracting surface 106 may be positioned at a pre-defined height from the light source 102 and configured to refract the received light beam from the light source 102. The refracted light beam may exit from the light exiting surface 112, as shown in FIG. 2.
[0053] In an exemplary embodiment, as shown in FIG. 2, when the light beam such as AA, AB, or the like from the Lambertian LED light source incident on the freeform center refracting surface 106, they are refracted by the freeform center refracting surface, and the refracted rays, i.e., AA1, AB1 or the like exit from the lens 104 through the light exiting surface 112.
[0054] The refracted light rays or the points of refraction at the freeform center refracting surface are calculated using Snell’s law of refraction.

=Angle of incidence of the light ray
Angle of refraction of the light ray
=Refractive index of first medium air and is equal to 1
=Refractive index of the second medium, i.e., collimator material (PC/PMMA)
( =1.586 for PC= 1.492 for PMMA)
[0055] The light beam (i.e., a set of rays) generated from the Lambertian LED source is considered at equal intervals of angles between them. The first light ray AA from the Lambertian LED source hits an arbitrary point taken according to the required height of the freeform center refracting surface, and the refracted ray AA1 at the point of incidence is calculated using Snell’s law of refraction. The tangential plane at the point of incidence is created with reference to the incident and refracted rays. Further, the second refracted ray AB1 of the second ray AB from the light source is calculated using Snell’s law of refraction and with reference to the tangential plane of the ray AA. The points of refraction are calculated for some arbitrary number of rays from the Lambertian LED source using the above-mentioned procedure. The points of refraction are fitted to obtain a curve to form the freeform center refracting surface.
[0056] The freeform center refracting surface 106 is designed by modifying the refraction angles at specific refraction points to get desired beam pattern.
[0057] In an embodiment, segmented side refracting surfaces 108 is connected to all four edges of the first refracting surface 106. The segmented side refracting surfaces 108-a and 108-b is configured to refract the light beam received from the light source 102. In another embodiment, the freeform center refracting surface 106 have a first end 122-1 and a second end 122-2, and the first end 122-1 of the freeform center refracting surface 106 may be coupled to a first end 126-1 of one of the segmented side refracting surfaces 108-a, and the second end 122-2 of the freeform center refracting surface 106 may be coupled to a first end 124-1 of another side refracting surface 108-b, as shown in FIG. 2.
[0058] In an embodiment, the segmented freeform TIR surfaces 110 is designed using ray tracing and surface construction method, and the segmented freeform TIR surfaces 110 act as a light collection and a light distribution element by eliminating requirement of any additional optics to attain the photometry pattern. Additionally, the first end 128-1 and 130-1 of the segmented freeform TIR surfaces 110-a and 110-b may be connected to at least one of the second end 124-2 and 126-2 of each of the segmented side refracting surfaces 108-a and 108-b respectively. Further, the segmented freeform TIR surfaces 110 are configured to facilitate total internal reflection (TIR) from the received refracted light beam.
[0059] In an exemplary embodiment, when the light beam (i.e., a set of rays) such as BA, BB, or the like from the Lambertian LED light source incident on the side refracting surface 108-b, they are refracted by the side refracting surface 108-b, and the refracted rays i.e., BA1, BA2, or the like incident on the freeform TIR surface 110-b. The segmented side refracting surfaces 108-a and 108-b are created in CAD software with draft angle at a specific distance from the center of the Lambertian LED source. Upon incident, BA1, BA2, or the like gets reflected, and reflected rays BA2, BB2, or the like exit through the light exiting surface 112, as shown in FIG. 3.
[0060] Using Snell’s law of refraction, angle of refraction is calculated, the refracted ray BA1 is generated for the ray BA from the Lambertian LED source, and the point of incidence of ray BA1 may be taken arbitrarily at a certain distance from the side refracting surface. The reflected ray BA2 may be created at the arbitrary point (point of reflection) taken as the point of incidence according to the required output beam deviation. Further, the tangential plane is created at the point of reflection with reference to the incident and reflected rays. Firstly, the ray BB gets refracted through the segmented side refracting surface108-b and the refracted ray is BB1, then the reflected ray BB2 may be created according to required output beam angle and with reference to the tangential plane created at the point of reflection of ray BA2. Discrete points of reflection are generated for arbitrary number of rays using the above procedure.
[0061] This locus of points of reflection is fitted to get 2D contour or spline for the segmented freeform TIR surfaces creation, also Bezier curve function is used to get a smooth transition between control points of the spline. The required horizontal spread of output beam pattern is controlled using the angle of reflection. Further, the obtained 2D spline is further divided into different sections and arcs of different radius of curvatures are created at each section to control the vertical spread, and 3D surface is developed from the 2D contour using CAD design software using the spline, and the section arcs.
[0062] Furthermore, all the segmented freeform total internal reflecting surfaces 110 of the segmented freeform lens are individually designed according to the required output light distribution. The individually designed freeform TIR surfaces are combined to achieve the desired photometry beam pattern for specific lighting functions.
[0063] In an embodiment, the light exiting surface 112 may be any of planar and curved shapes. The light exiting surface 112 may be positioned at a front end of the segmented freeform optic element 104, and at a free end of the segmented freeform TIR surfaces 110. Additionally, the light exiting surface 112 is configured to generate the desired photometry pattern from the refracted beam (i.e., AA1, AB1, etc.), received from the freeform center refracting surface 106, and the reflected light beam (i.e., BA2, BB2, etc.), received from the segmented freeform TIR surfaces 110. Furthermore, the photometry pattern can be achieved for automotive lamps rear fog lamp, warning lamp, front fog lamp, and corner lamp.
[0064] In an embodiment, the desired photometry pattern corresponds to the photometry requirement of the automotive lighting function to be achieved. The photometry requirements for the automotive lamps are defined in ECE regulation.
[0065] Referring to FIG. 4 an exemplary isometric view of a segmented freeform optic element 104 of an automotive lamp 100 for rear fog function is depicted, and in FIG. 5, an exemplary front view of segmented freeform optic element 104 of automotive lamp 100 for rear fog function is depicted.
[0066] Referring to FIG. 6, exemplary four segments i.e., a first segment 602, a second segment 604, a third segment 606, a fourth segment 608 of freeform TIR surfaces of a segmented freeform optic element 104 for rear fog lamp are depicted. The rear fog and warning functions are achieved with segmented freeform optic element having four freeform TIR segments.
[0067] Referring to FIG. 7, an exemplary isometric view of a segmented freeform optic element 104 for front fog and corner lamp is depicted, and in FIG. 8, an exemplary front view of a segmented freeform optic element for front fog and corner lamp. The segmented freeform optic element 104 creates combined output photometry pattern for front fog and corner lamp.
[0068] Referring to FIG. 9 exemplary eight segments i.e., a first segment 902, a second segment 904, a third segment 906, a fourth segment 908, a fifth segment 910, a sixth segment 912, a seventh segment 914, and an eighth segment 916 of freeform TIR surfaces of a segmented freeform optic element 104 for front fog and corner lamp is depicted. The front fog and corner lamp are achieved with segmented freeform optic element having eight freeform TIR segments.
[0069] Referring to FIG. 10, an ECE R38 Rear Fog photometry pattern achieved with proposed automotive lamp 100 is depicted.
[0070] Referring to FIG. 11, the ECE R65 warning lamp (Category X) narrow angle photometry pattern achieved with proposed automotive lamp 100 is depicted. In addition, a symmetric photometry pattern is achieved for warning lamp designed with the proposed automotive lamp 100. Further, warning lamp designed with the segmented freeform optic element 104 can be used in both horizontal and vertical mounting.
[0071] In an embodiment, the segmented freeform lens may generate a customized symmetric photometry pattern for a common lamp for both LH and RH side of the vehicle, where the common lamp includes a position lamp.
[0072] Referring to FIG. 12 illustrates the front fog and corner lamp photometry pattern achieved with proposed automotive lamp 100, in accordance with an embodiment of the present disclosure. ECE R19 Class F3 front fog and R119 corner lamp photometry patterns are combinedly achieved with segmented freeform optic element 104. The segmented freeform optic element 104 generates the symmetric photometry pattern of front fog and corner function for both LH and RH side of the vehicle, and the segmented freeform optic element includes eight freeform TIR segments.
[0073] FIG. 13 illustrate an asymmetrical photometry pattern of front fog and corner functions for one side (i.e. RH side) lamp according to the ECE R19 and ECE R119 regulations of front fog and corner lamp respectively. Additionally, the segmented freeform optic element 104 generates the asymmetric photometry pattern for front fog and corner function, for LH and RH side of the vehicle separately, and the segmented freeform optic element includes eight freeform TIR segments.
[0074] Further, the proposed automotive lamp 100 with segmented freeform optic element 104 meets the European vehicle regulations R38, R65, R19, and R119 of the rear fog lamp, warning lamp, front fog lamp, and corner lamp respectively as shown in Table 1 to 4.
EXAMPLE
Table 1: Photometry table of Rear Fog Lamp (ECE Regulation R38)
TABLE 1
Photometry Table of Rear fog lamp (ECE Regulation R38)
Test Points Minimum Intensity requirement (cd) Maximum Intensity requirement (cd) Intensity value (cd) Regulation check (OK/NOK)
H,5U 150 300 243 OK
5L,2.5U 75 300 197 OK
H,2.5U 150 300 251 OK
5R,2.5U 75 300 191 OK
10L,V 150 300 242 OK
5L,V 150 300 195 OK
H,V 150 300 216 OK
5R,V 150 300 196 OK
10R,V 150 300 241 OK
5L,2.5D 75 300 193 OK
H,2.5D 150 300 245 OK
5R,2.5D 75 300 198 OK
H,5D 150 300 231 OK
Rhombus 75 300 189.9 OK
H-H 150 300 192.8 OK
V-V 150 300 212.5 OK
Emax 300 269.5 OK

Table 2: Photometry Table of Warning Lamp (Category X Blue by day narrow angle) (ECE Regulation R65)

TABLE 2
Photometry Table of Warning lamp (ECE Regulation R65)
Test Points Minimum Intensity requirement (cd) Maximum Intensity requirement (cd) Intensity value (cd) Regulation check (OK/NOK)
10L,8U 100 1000 188 OK
10R,8U 100 1000 214 OK
20L,6U 100 1500 163 OK
10L,6U - 1500 233 OK
H,6U 150 1500 261 OK
10R,6U - 1500 247 OK
20R,6U 100 1500 169 OK
30L,4U 40 1000 116 OK
10L,4U 200 3000 244 OK
10R,4U 200 3000 255 OK
30R,4U 40 1000 114 OK
30L,V 100 1000 128 OK
20L,V 150 1500 186 OK
H,V 200 3000 263 OK
20R,V 150 1500 187 OK
30R,V 100 1000 127 OK
30L,4D 40 1000 112 OK
10L,4D 200 3000 252 OK
10R,4D 200 3000 242 OK
30R,4D 40 1000 116 OK
20L,6D 100 1500 171 OK
10L,6D - 1500 248 OK
H,6D 150 1500 260 OK
10R,6D - 1500 230 OK
20R,6D 100 1500 160 OK
10L,8D 100 1000 216 OK
10R,8D 100 1000 188 OK

Table 3: Photometry Table of Front Fog Lamp (Class F3) (ECE Regulation R19)
TABLE 3
Photometry Table of Front Fog lamp (ECE Regulation R19)
Test Points Minimum Intensity requirement (cd) Maximum Intensity requirement (cd) Intensity
Value (cd) Regulation check (OK/NOK)
P1 — 85 0 OK
P2 — 85 0 OK
P3 — 85 1 OK
P4 — 85 2 OK
P5 — 85 5 OK
P6 — 85 3 OK
P7 — 85 1 OK
P8 — 85 2 OK
P9 — 85 4 OK
P10 — 85 4 OK
L1 — 130 37 OK
L2 — 150 9 OK
L3 — 245 9 OK
L4 — 360 58 OK
L5 — 485 20 OK
L6 2700 4153 OK
L6 Max — 4449 OK
L7<50% L6 — 2224 1613 OK
L8-L 1100 4000 OK
L8-R 1100 4000 OK
L9-L 450 1980 OK
L9-R 450 1970 OK
ZoneD — 12000 4750 OK

Table 4: Photometry Table of Corner Lamp (ECE Regulation R119)
TABLE 4
Photometry Table of Corner lamp (ECE Regulation R119)
Test Points Minimum Intensity requirement (cd) Maximum Intensity requirement (cd) Intensity Value (cd) Regulation check (OK/NOK)
2.5D 30L 240 — 2564 OK
2.5D 45L 400 — 1475 OK
2.5D 60L 240 — 525 OK
HH-1U L-R — 600 228 OK
>1U — 300 233 OK
<0.57D — 14000 3990 OK

[0075] Referring to FIG. 14A, an exemplary perspective view for two, segmented freeform optic elements 104-1 and 104-2, assembled for rear fog light output distribution is depicted. The segmented freeform optic elements 104-1 and 104-2 are assembled to get preferred photometry pattern. Further, an assembly of the two segmented freeform optic elements generates the rear fog photometry pattern, where each of the segmented freeform optic elements may include four freeform TIR segments.
[0076] Referring to FIG. 14B, an exemplary perspective view for six, segmented freeform optic elements 104-1, 104-2, 104-3, 104-4, 104-5, and 104-6, assembled for warning lamp light output distribution is depicted. The segmented freeform optic elements 104-1, 104-2, 104-3, 104-4, 104-5, and 104-6 are assembled to get preferred photometry pattern.
[0077] The segmented freeform optic element of the automotive lamp with four freeform TIR segments can achieve rear fog photometry pattern, and the segmented freeform optic element of the automotive lamp with eight freeform TIR segments provide photometry pattern of front fog and corner lamp.
[0078] In an embodiment, an assembly of the six segmented freeform optic elements generates the warning lamp (Category X) narrow angle photometry pattern, where each of the segmented freeform optic elements comprise four freeform TIR segments. In another embodiment, an assembly of the six segmented freeform optic elements generates a customized symmetric photometry pattern for warning lamp that is suitable for both horizontal and vertical mounting, where each of the segmented freeform optic elements comprise four freeform TIR segments.
[0079] The segmented freeform lens in the proposed concept can satisfy the photometry requirements of road illumination functions such as front fog lamp, corner lamp and lighting functions such as rear fog lamp and warning lamp. The segmented freeform lens achieves symmetrical or asymmetrical light distribution of automotive lighting functions. In addition, light distribution from the segmented freeform optic element fulfils the photometric requirements of both left hand (LH) and right hand (RH) side lamps of vehicle for front fog and corner functions. Customized symmetric light distribution for the functions such as warning lamp can be achieved and used in both horizontal and vertical mounting.
[0080] The segmented freeform lens can be used for front fog and corner lamp for LH and RH side of the vehicle separately.
[0081] Therefore, the proposed lamp 100 can be used as a standalone module and also as a part of automotive lamp to enhance the light distribution. Additionally, automotive lamp 100 disclosed that rear fog lamp, warning lamp, front fog and corner lamp photometry patterns are generated without need for any additional optics elements, and with higher efficiency being achieved. Furthermore, the proposed automotive lamp 100 is lighter in weight and utilizes simpler and more cost-effective methods, which improve its mechanical stability and longevity.
[0082] In an embodiment, the automotive lamp is configured to achieve specific or complex light distribution without any additional front optics, as light collection optics and light distribution optics are same. The elimination of additional optics reduces size of the optic element and save the additional manufacturing cost of the additional optics or elements. Thus, optical losses also decrease due to the less number of optic elements.
[0083] Thus, the present disclosure provides the automotive lamp with Lambertian LED light source and the segmented freeform lens that combines the latest in LED and lens technology to produce a specific photometry pattern. Its combination of light output from the LED source and precise control over the light from the segmented freeform lens make it an ideal solution for signaling and specific illumination functions.
[0084] The proposed segmented freeform optic element can also be used to design small lit opening optical systems, as it is possible to design optical systems with different styling lit opening requirements, which are difficult to realize with reflectors.
[0085] It should be apparent to those skilled in the art that many more modifications besides those already described are possible without departing from the inventive concepts herein. The inventive subject matter, therefore, is not to be restricted except in the spirit of the appended claims. Moreover, in interpreting both the specification and the claims, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprise” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.
[0086] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims.
[0087] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions, or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to those having ordinary skill in the art.

ADVANTAGES OF THE INVENTION
[0088] The present disclosure provides an automotive lamp to achieve desired light distribution.
[0089] The present disclosure provides an automotive lamp that has high optical efficiency. The high efficiency reduces input LED luminous flux requirements that tend to reduction in power requirements, and reduction in power enhances thermal stability and cost-effectiveness.
[0090] The present disclosure provides an automotive lamp where light collection optics and light distribution optics are same.
[0091] The present disclosure provides an automotive lamp that eliminates need of additional optics thus reducing size of optic element used and saving additional manufacturing cost of additional optic elements.
[0092] The present disclosure provides an automotive lamp that is lighter in weight, as it is smaller in size compared to traditional lamps.
[0093] The present disclosure provides an automotive lamp that is used with a Lambertian LED light source, where photometry requirement is to be met with small package size and less number of parts with high efficiency.
, Claims:1. An automotive lamp (100) for a motor vehicle comprising:
a light source (102) configured to generate a light beam;
a segmented freeform optic element (104) optically connected to the light source, and the segmented freeform optic element (104) comprises a plurality of surfaces configured to collect the light beam from the light source on each of the plurality of surfaces and combinedly generate desired photometry pattern corresponding to type of the automotive lighting function, and wherein the segmented freeform optic element (104) comprises:
a first refracting surface (106) positioned at a pre-defined height from the light source, and configured to refract the received light beam from the light source;
one or more second refracting surfaces (108) standing substantially connected to all four edges of the first refracting surface, and wherein the one or more second refracting surfaces are configured to refract the light beam received from the light source;
one or more third reflecting surfaces (110) connected to one end of each of the one or more second refracting surfaces, wherein the one or more third reflecting surfaces having freeform shape and configured to facilitate total internal reflection (TIR) from the received refracted light beam; and
a fourth surface (112) positioned at a front end of the segmented freeform optic element (104), wherein the fourth surface is configured to generate the photometry pattern by refracting the received beam from the first refracting surface, and the reflected light beam from the one or more third reflecting surfaces.

2. The automotive lamp as claimed in claim 1, wherein, the light source (102) is Lambertian LED light source.
3. The automotive lamp as claimed in claim 1, wherein, the first refracting surface (106) is a freeform center refracting surface, and the one or more second refracting surfaces (108) are segmented side refracting surfaces, and the one or more third reflecting surfaces (110) are segmented freeform total internal reflecting (TIR) surfaces.

4. The automotive lamp as claimed in claim 1, wherein the first refracting surface (106) is having a first end and a second end, wherein the first end of the first refracting surface is coupled to a first end of one of the one or more second refracting surfaces (108), and the second end of the first refracting surface is coupled to a first end of another one of the one or more second refracting surfaces (110).

5. The automotive lamp as claimed in claim 1, wherein a first end of each of the one or more third reflecting surfaces is coupled to a second end of at least one of the one or more second refracting surfaces.

6. The automotive lamp as claimed in claim 1, wherein, the one or more third reflecting surfaces are designed using ray tracing and surface construction method, and the one or more third reflecting surfaces act as a light collection and a light distribution element by eliminating requirement of any additional optics to attain the photometry pattern.

7. The automotive lamp as claimed in claim 1, wherein, the fourth surface (112) is a light exiting surface and the fourth surface is of any of planar and curved shape.

8. The automotive lamp as claimed in claim 1, wherein, the fourth surface (112) is positioned at a free end of the one or more third reflecting surfaces.

9. The automotive lamp as claimed in claim 1, wherein the segmented freeform optic element (104) generates symmetrical or asymmetrical photometry light distribution.

10. The automotive lamp as claimed in claim 1, wherein the segmented freeform optic element (104) generates the photometry pattern of any of rear fog lamp, warning lamp (Category X), and combination of front fog and corner lamp, corresponding to their associated regulations including ECE R38, R65, R19, and R119 respectively.

11. The automotive lamp as claimed in claim 1, wherein an assembly of the two segmented freeform optic elements generates the rear fog photometry pattern, wherein each of the segmented freeform optic elements comprise four freeform TIR segments.

12. The automotive lamp as claimed in claim 1, wherein an assembly of the six segmented freeform optic elements generates the warning lamp (Category X) narrow angle photometry pattern, wherein each of the segmented freeform optic elements comprise four freeform TIR segments.

13. The automotive lamp as claimed in claim 1, wherein an assembly of the six segmented freeform optic elements generates a customized symmetric photometry pattern for warning lamp (Category X) that is suitable for both horizontal and vertical mounting, wherein each of the segmented freeform optic elements comprise four freeform TIR segments.

14. The automotive lamp as claimed in claim 1, wherein the segmented freeform optic element (104) generates a customized symmetric photometry pattern for a common lamp for both LH and RH side of the vehicle, wherein the common lamp includes a position lamp.

15. The automotive lamp as claimed in claim 1, wherein the segmented freeform optic element (104) generates the symmetric photometry pattern of front fog and corner function for both LH and RH side of the vehicle, wherein the segmented freeform optic element comprises eight freeform TIR segments.

16. The automotive lamp as claimed in claim 1, wherein the segmented freeform optic element (104) generates the asymmetric photometry pattern for front fog and corner function, for LH and RH side of the vehicle separately, wherein the segmented freeform optic element comprises eight freeform TIR segments.