Description:TECHNICAL FIELD
[0001] The present disclosure, in general, relates to signaling lamps. More particularly, it relates to an LED-based signaling lamp for transforming light into a preferred shape or intensity distribution using a multilevel diffractive optical element (DOE).

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] Automobiles are transforming from internal combustion (IC) engine to Battery powered transmissions which are also revamping styling of the automobiles. Automotive lighting is used as a key element in styling and is a major differentiator in vehicle aesthetics and user experience. The current trends in the market show the demand for thin illuminating surfaces to meet photometry targets with less package/weight to enhance the Vehicle performance.
[0004] Signaling lamps in current vehicles use optics which are defined by using ray tracing principles based on Ray Optics (Geometrical Optics). Most signaling lamp optics are based on Refraction, Reflection, Total Internal Reflection, Surface and Volume Scattering.
[0005] Diffractive Optics is relatively new in automotive application and there is no tool readily available to design the DOE for a specific automotive function. In order to define the DOE for an automotive application the person should have in-depth knowledge of wave optics, automotive photometric requirements, and the methodology to design manufacturable optical concepts. There is no benchmark lamp available in market which is satisfying signaling function photometry with DOE. Diffractive optics in general most of the cases is associated with LASER sources than LED sources. There are way many properties which makes LED differ from a LASER source. But LED can still act as a potential source for Diffractive Optics for pattern generation especially for automotive domain.
[0006] There is, therefore, a need to overcome the above drawback, limitations, and shortcomings associated with LED and Diffractive Optics for a signaling lamp by providing a solution to transform the LED light beam into a preferred shape automatically using a diffractive optical element for signaling lamp application

OBJECTS OF THE PRESENT DISCLOSURE
[0007] Some of the objects of the present disclosure, which at least one embodiment herein satisfy are as listed herein below.
[0008] A general object of present disclosure is to overcome the above drawback, limitations, and shortcomings associated with the existing signaling lamp, by providing a signaling lamp that achieves required output pattern for signaling function using binary or multilevel diffractive optic elements.
[0009] Another object of the present disclosure is to provide a signaling lamp that increases visibility of the vehicle to other drivers, pedestrians, and bicyclists, making it easier for them to see the vehicle's intentions and react accordingly.
[0010] Another object of the present disclosure is to provide a signaling lamp that uses a diffractive optic element designed by Eikonal method to generate a continuous phase profile.
[0011] Another object of the present disclosure is to provide a signaling lamp that is designed as small as possible, which also decreases number of components and overall size of the signaling lamp.
[0012] Another object of the present disclosure is to design a signaling lamp that employs a diffractive optical element to shape the input beam pattern for a specific purpose.
[0013] Another object of the present disclosure is to provide a signaling lamp that is lighter in weight, as it is smaller in size compared to traditional signaling lamps.
[0014] Another object of the present disclosure is to design a signaling lamp that utilizes simpler or more cost-effective methods and improves the mechanical stability and longevity of the signaling lamp.
[0015] Another object of the present disclosure is to provide a signaling lamp that helps improve safety by making the vehicle more visible in extreme weather and helps to reduce risk of accidents and collisions.

SUMMARY
[0016] Various aspects of present disclosure relate to signaling lamp. More particularly, it relates to an LED-based signaling lamp for transforming light into a preferred shape by a multilevel diffractive optical element (DOE). The present disclosure provides the signaling lamp that achieves required output pattern for signaling function using the multilevel DOE that increases visibility of the vehicle to other drivers, pedestrians, and bicyclists, making it easier for them to see the vehicle's intentions and react accordingly. Additionally, the signaling lamp utilizes a diffractive optical element designed by Eikonal method to generate a continuous phase profile, and the signaling lamp may be designed as small as possible, which also decreases the number of components and overall size of the signaling lamp. Further, the signaling lamp is lighter in weight and utilizes simpler or more cost-effective methods, which improve its mechanical stability and longevity.
[0017] The signaling lamp includes a light source configured to generate a light beam, a primary optic element optically connected to the light source, and a diffractive optical element (DOE) optically connected to the primary optic element. The light source is a polychromatic LED light source and has a narrow linewidth of wavelength with a full-width half maximum (FWHM) of approximately (25-30 nm). The primary optic element may be configured to collect the light beam from the light source and collimate the collected light beam, and the DOE is configured to diffract the collimated light beam on a target plane. Upon diffraction, the collimated light beam generates one or more pre-defined patterns corresponding to pre-defined photometry requirements for the signaling lamp of the automotive vehicle, and the DOE generates the one or more symmetric patterns such as parallelogram, rectangle, etc. using Eikonal technique on the target plane.
[0018] In an aspect, the DOE may be configured to generate the patterns corresponding to type of the signaling lamp, and type of the signaling lamp may be tail lamp, rear fog lamp, brake light, hazard warning light, indicator light, and side marker lamp.
[0019] In an aspect, the DOE may be made of a light transmitting material and segmented into a plurality of pixels, and each pixel may be associated to a phase value, and the phase value generated by the Eikonal technique corresponding to the patterns required by the motor vehicle.
[0020] In an aspect, the Eikonal technique facilitates the design of DOEs with continuous phase profile. The generated continuous phase profile is verified by Fourier transform method.
[0021] 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
[0022] 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.
[0023] FIG. 1 illustrates a block diagram of a signaling lamp for a motor vehicle, in accordance with an embodiment of the present disclosure.
[0024] FIG. 2A illustrates an exemplary pattern at a target plane for rear fog function of a signaling lamp, in accordance with an embodiment of the present disclosure.
[0025] FIG. 2B illustrates an exemplary pattern at a target plane for tail function of a signaling lamp, in accordance with an embodiment of the present disclosure.
[0026] FIG. 3 illustrates an exemplary representation of photometry intensity pattern for rear fog function of a signaling lamp as per ECE regulation, in accordance with an embodiment of the present disclosure.
[0027] FIGs. 4A-4B illustrate exemplary representations of distance calculation for different angles extended at 1 meter for rear fog function of a signaling lamp, in accordance with an embodiment of the present disclosure.
[0028] FIG. 5 illustrates an exemplary representation of photometry intensity pattern for rear fog function of a signaling lamp at 1 meter, in accordance with an embodiment of the present disclosure.
[0029] FIGs. 6A-6B illustrate exemplary representations of photometry intensity patterns for rear fog function of a signaling lamp at 1 meter to enhance photometry points, in accordance with an embodiment of the present disclosure.
[0030] FIGs. 7A-7B illustrate exemplary representations of distance calculation for different angles extended at 1 meter for tail function of a signaling lamp, in accordance with an embodiment of the present disclosure.
[0031] FIG. 8 illustrates an exemplary representation of photometry intensity pattern for rear position, Stop, Turn, of a signaling lamp as per ECE regulation, in accordance with an embodiment of the present disclosure.
[0032] FIG. 9 illustrates an exemplary representation of distance evaluated for photometry intensity pattern for rear signaling at 1 meter of a signaling lamp, in accordance with an embodiment of the present disclosure.
[0033] FIG. 10 illustrates an exemplary representation of photometry intensity pattern for rear signaling at 1 meter to enhance photometry points of a signaling lamp, in accordance with an embodiment of the present disclosure.
[0034] FIG. 11 illustrates an exemplary graph of output of LED with primary optics fitted with a Gaussian curve, in accordance with an embodiment of the present disclosure.
[0035] FIG. 12 illustrates an exemplary input plane with a meshed Gaussian beam with N x N nodes, in accordance with an embodiment of the present disclosure.
[0036] FIG. 13A illustrates an exemplary output mesh for a square pattern, in accordance with an embodiment of the present disclosure.
[0037] FIG. 13B illustrates an exemplary output mesh for a rhombus pattern, in accordance with an embodiment of the present disclosure.
[0038] FIG. 14A illustrates an exemplary mapping of an output plane for a square pattern with an input plane mesh of Gaussian, in accordance with an embodiment of the present disclosure.
[0039] FIG. 14B illustrates an exemplary mapping of an output plane for a rhombus pattern with an input plane mesh of Gaussian, in accordance with an embodiment of the present disclosure.
[0040] FIG. 15A illustrates a phase graph with phase values at node points for square output, in accordance with an embodiment of the present disclosure.
[0041] FIG. 15B illustrates a phase graph with phase values at node points for rhombus output, in accordance with an embodiment of the present disclosure.
[0042] FIG. 16A illustrates a phase graph of DOE for square output, in accordance with an embodiment of the present disclosure.
[0043] FIG. 16B illustrates a phase graph of DOE for rhombus output, in accordance with an embodiment of the present disclosure.
[0044] FIG. 17A illustrates an output intensity graph of DOE for Gaussian to square from Fourier Transform method, in accordance with an embodiment of the present disclosure.
[0045] FIG. 17B illustrates an output intensity graph of DOE for Gaussian to rhombus from Fourier Transform method, in accordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION
[0046] 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 relate to the signaling lamp. More particularly, it relates to an LED-based signaling lamp for transforming light into a preferred shape by a phase diffractive optical element (DOE). The present disclosure provides the signaling lamp that achieves required output pattern for signaling function using multilevel DOE.
[0047] According to an embodiment of present disclosure a signaling lamp is disclosed that includes a light source configured to generate a light beam, a primary optic element optically connected to the light source, and a diffractive optical element (DOE) optically connected to the primary optic element. The light source is a polychromatic LED light source having a narrow linewidth of wavelength with a Full width half maximum (FWHM) of approximately (25-30 nm). The primary optic element may be configured to collect the light beam from the light source and collimate the collected light beam, and the DOE may be configured to diffract the collimated light beam on a target plane. Upon diffraction, the collimated light beam generates one or more pre-defined patterns corresponding to pre-defined photometry requirements for the signaling lamp of the motor vehicle, and the DOE generates the one or more patterns such as parallelogram, rectangle, etc. on the target plane.
[0048] In an embodiment, the DOE may be configured to generate the patterns corresponding to type of the signaling lamp, and type of the signaling lamp may be tail lamp, rear fog lamp, break light, hazard warning light, indicator light, and sidemarker lamp.
[0049] In an embodiment, the DOE may be made of a light transmitting material and segmented into a plurality of pixels, and each pixel may be associated to a phase value, and the phase value may be generated by the Eikonal technique corresponding to the patterns required by the motor vehicle.
[0050] In an embodiment, the Eikonal technique facilitates the design of a diffractive element, and the generated diffractive element may be a continuous phase profile. The generated continuous phase profile is verified by Fourier transform method.
[0051] FIG. 1 illustrates a block diagram of a signaling lamp for a Automotive vehicle, in accordance with an embodiment of the present disclosure.
[0052] As illustrated, a signaling lamp 100 for a motor vehicle is disclosed. The motor vehicle can be a car, bus, truck, van, two-wheeler, or the like. The signaling lamp 100 can be indicators, brake light, hazard warning light, headlights, reversing light, or the likes. signaling lamp 100 of the motor vehicle runs at a high speed is desired to brightly illuminate a forward/backward/side of the motor vehicle. In an exemplary embodiment, the signaling 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 rear or front part of the motor vehicle and is provided with one or more transparent or semi-transparent, optionally also coloured, areas or portions.
[0053] The signaling lamp 100 includes a light source 102, a primary optic element 104, and a diffractive optical element (DOE) 106. The light source 102 is a polychromatic LED of narrow linewidth of wavelength with a full width at half maximum (FWHM) of approximately 25-30nm or lesser and the primary optical element 104 is in the form of a collimator designed to make the output profile fitting more closer to Gaussian profile. Additionally, the light source 102 provides light of several wavelengths. In an exemplary embodiment, the signaling lamp 100 can be installed in a headlamp or rear lamp of the Automotive vehicle.
[0054] In an embodiment, the primary optic element 104 may be a conventional collimator to collect beam of light from the light source, collimate the collected light beam and moreover used to reduce the spatial cross-section of a beam to make it smaller. The primary optic element 104 change or collect all the input flux of light or other radiation coming from the light source 102 into a parallel beam.
[0055] In an embodiment, the DOE 106 may be optically connected to the primary optic element 104, and configured to diffract the collimated light beam on and directs the light beam to an area to be illuminated i.e., a target plane 108. The DOE 106 is an element that performs a diffraction action on the light emitted from the light source 102. The illustrated DOE 106 diffracts the light from the light source 102 and directs the light to the area to be illuminated. In an exemplary embodiment, according to this example, when the light source emits light beam of different wavelength ranges, the diffractive optical elements 106 can diffract corresponding light beam of different wavelength. Additionally, the signaling lamp 100 is capable of projecting, one or more patterns of a predetermined shape directly onto road surface or other flat surface external and adjacent to the motor vehicle. Moreover, the pattern preferably has shape of parallelogram, square, or another coded graphical sign that can be advantageously used as fog lamp or tail lamp or any other signaling lamp or patterns that enhances the photometry of the signaling lamps
[0056] The DOE 106 are micro-size optic elements which work on the principle of diffraction of Light, i.e., bending of the light beam around corners or through an aperture or slit that is physically of same size or smaller than the wavelength of the light beam. Upon diffraction, the collimated light beam generates one or more pre-defined patterns (collectively referred to as patterns and individually referred to as pattern, hereinafter) corresponding to pre-defined photometry requirements for the signaling lamp of the motor vehicle. The pre-defined photometry requirements for the signaling lamp are defined in ECE regulation. Further, the DOE designed by Eikonal technique generates the one or more patterns on the target plane.
[0057] In an exemplary implementation, the primary optic element 104 collects as much light as possible from the light source 102 and collimate light beam that further incident on the DOE 106. To get the pattern, minimum DOE area is required, and further beam width of light output of the primary optics must be tuned to match the DOE 106 area's size for higher efficiency. In another exemplary implementation, the primary optic element 104 can be eliminated if the light source is a Laser source or if LED is placed closer to the DOE and the DOE is designed with respect to Lambertian emission profile instead of Gaussian profile 106.
[0058] In an embodiment, the DOE may be configured to generate the patterns corresponding to type of the signaling lamp The type of the signaling lamp is selected from a group consisting of tail lamp, rear fog lamp, break light, warning lamp, and indicator light, side Marker Lamp. Further, the DOE is made of a light-transmitting material and segmented into a plurality of pixels, and each pixel is associated to a phase value. The phase value may be generated by the Eikonal technique corresponding to the patterns required by the motor vehicle regulation.
[0059] In an embodiment, pixels are designed for a specific wavelength that generates a sharp pattern in the target plane and remaining wavelengths falling on the plurality of pixels creates a blurred pattern on the target plane. Further, combination of the sharp pattern and the blurred pattern defines the required pattern corresponding to pre-defined photometry requirements such as Parallelogram, plus sign, or the like.
[0060] In an embodiment, the DOE 106 facilitates multilevel diffractive element designed by the Eikonal technique, and the generated diffractive element is of a continuous phase profile. The generated continuous phase profile is verified by the Fourier transform method. Additionally, the collimated beam is altered by the pixels of the DOE by changing the phase content of the received collimated beam incident on the DOE. The phase content is altered by changing optical path length to get the continuous phase profile for the required at least one of the pattern.
[0061] In an exemplary embodiment, the light beam from the light source 102 is modified by the DOE pixels by changing the phase content of the light falling on it. The phase is modified by changing optical path length to get a phase profile for desired pattern for automotive signaling application. The pixels in the DOE 106 which phase controlling surfaces defined by the Eikonal technique and verified by Fourier Transform method. Further, design methodology for DOE is disclosed, where input beam and output pattern is meshed to get same number of node points and following the same sequence for creating node points for both input and output mesh where mesh zones of input plane lies as much as closer to the zones and nodes of output plane for Eikonal technique.
[0062] In an exemplary embodiment, each signaling lamp 100 includes a transmission surface at exit surface of the lamp arranged at rear or front of the motor vehicle styling surface, substantially at point where the rear or front signaling lamp is usually arranged. Additionally, regulatory photometric characteristics of the signaling lamps such as the position lights, direction indicator, stop light or fog light are well defined. They relate notably to the minimum and maximum light intensity ranges to be observed, visibility angle of the light beam, color of the light beam, surface area of light surface of function, or even the minimum distance between different functions.
[0063] In an embodiment the DOE 106 may be configured to generate the pattern from the light beam which meets all required regulatory requirements. The single pattern can notably fulfill several functions simultaneously or alternately, such as, for example, fog light, tail light or etc. Several patterns can also be displayed simultaneously or alternately, each pattern filling the photometric characteristics of a different function of the signaling lamp.
[0064] Referring to FIG. 2A and FIG. 2B exemplary patterns at a target plane for rear fog function and tail function of a signaling lamp, respectively are disclosed. When a rear fog signaling lamp of a motor vehicle is turned ON, a rhombus may be generated on the target plane that reveal position of the motor vehicle when driving in fog, snow or other conditions that limit visibility and reduce chance of an accident of the motor vehicle in low visibility. Similarly, when a tail signaling lamp (i.e., headlights or tail lamp) of the motor vehicle is turned ON, a square or rectangle generated on the target plane. The tail signaling lamps are helpful to make the motor vehicle visible to other vehicles behind it, with the help of tail signaling lamps, drivers of other vehicles may recognize distance with other vehicles travelling on road.
[0065] Referring to FIG. 3, an exemplary representation (i.e., rhombus) of photometry intensity pattern for rear fog function of a signaling lamp defined by ECE R-38 is disclosed. Intensity of light along H and V axes, between 10° to left and 10° to right and between 5° up and 5° down, shall not be less than 150 cd. If visual examination of the light appears to reveal substantial local variations of the intensity, a check shall be made to ensure that, outside the axes, no intensity measured within the rhombus defined by the extreme directions of measurement is below 75 cd.
[0066] Referring to FIGs. 4A-4B, exemplary representations of distance calculation for different angles extended at 1 meter for rear fog function of a signaling lamp 100, are disclosed. The pattern in meters at a 1-meter distance is calculated from triangles shown in FIGs. 4A and 4B.
X=176mm (for FIG. 4A)
X=87mm (for FIG. 4B)
[0067] Referring to FIG. 7A-7B, exemplary representations of distance calculation for different angles extended at 1 meter for tail function of a signaling lamp is disclosed.
tan (10°) =
Y/2 = 0.176

tan (20°) =
X/2 = 0.364
[0068] In an exemplary embodiment, the proposed signaling lamp can be used to obtain complete pattern of Rear Fog function as shown in FIG. 3 and FIG. 5. Similarly, the proposed signaling lamp can be used to obtain a plus sign as shown in FIGs. 6A and 6B covers photometric grid points which in turn helps to enhance regulation points. Further, the proposed signaling lamp can be used to obtain the complete pattern of rear Signaling function as shown in FIG. 8 and FIG. 9.
[0069] FIG. 8 is an exemplary representation of photometry intensity pattern for rear position, Stop, and Turn, defined by ECE R-07 for the signaling lamp. The ECE regulation for Rear signal Photometry from ECE R-07 is a rectangle pattern. To meet this pattern 1 meter away, maximum distance to be extended in Horizontal direction in H-H axis is 364mm from center (HV point). Similarly, to meet the pattern, the maximum distance to be extended in Vertical direction is 176mm from the center (HV Point).
[0070] In an embodiment, DOE 106 can be designed to obtain the target pattern in the form of:
a. Some or all of the grid lines which enhance the photometry regulation for Rear Fog function as shown in FIG. 6.
b. Some or all Grid Line Pattern which enhances photometric regulation for other signaling function as shown in FIG. 10.
Further, combination of DOE 106 in a single lens or multiple lens can satisfy one or more photometry requirements with the polychromatic single colored light source.
[0071] In an embodiment, a DOE window having size of diffractive optical element 106 of 500µm x 500µm can satisfy ECE regulation photometry requirement of Rear Fog functions, an exemplary representation of photometry intensity pattern for rear fog function at target plane is depicted.
[0072] In an exemplary implementation, ECE regulation for Rear Fog Photometry from ECE R-38 is a Parallelogram pattern as shown in FIG. 3. To meet this pattern 1 meter away, the maximum distance to be extended in horizontal direction in H-H axis is 0.176m from the center (HV point). Similarly, to meet the pattern, the maximum distance to be extended in vertical direction is 0.087m from the center (HV Point). To calculate Image size at the Target plane, the DOE Window with 500 x 500 pixels being used.
pixel size of each DOE = PDOE = 1µm x 1µm
sampling period (N) = 500
λ = 620 nm
size of image pixel at image plane at a distance of Z=1 is given by
PI = λ Z/(N x PDOE) = 1.24 mm
The size of the image window for the above NxN DOE is 620mm x 620mm at 1m. The pattern occupies a window of 284 x 141 pixels at the image window.
Similarly with N =800 & = 620 nm, PDOE= 1µm x 1µm PI will be 0.775mm. An input DOE pixel window of 1000 x 1000 makes an image plane size of 775mm x 775mm at 1 meter distance which can satisfy the signal function photometry pattern within.
[0073] In an embodiment, FIG. 11 illustrates an exemplary graph of output intensity fitted with a Gaussian curve, where a cross section curve graph taken as output of LED with collimator, and the curve graph is matched with a Gaussian Curve fit using MATLAB. The output of the Laser Beam is an intensity profile matching to Gaussian distribution, and Intensity output of LED is generally Lambertian distribution. The Gaussian property of Laser is explored by tuning the LED with primary optics output into a Gaussian fit profile. Further, LED output is approximated to a Gaussian profile after passing through a primary optics which is a collimator as shown in FIG. 11. Moreover, the input beam after the collimator output is assumed to be Gaussian incident on DOE. For calculation of the DOE phase this input beam is meshed to get “N-1 x N-1” number of zones. The zones are created such that area under each zone makes equal power. Therefore, energy in each zone is always same in the input plane.
[0074] In an embodiment, FIG. 12 illustrates an exemplary input plane with a meshed output of a Gaussian beam with NxN nodes. The meshed Gaussian beam at the input plane with N x N nodes, where N used in the figure is 21, and four adjacent node points forms a zone. Further, dots shown in FIG. 12 are corners or nodes of equal power zones. The sequence at which the input mesh is created is highly important in Eikonal method. The same sequence needs to be followed while meshing desired pattern of output plane. The input plane mesh is created such a way that outer ring of the upper half is created first and outer ring of the lower half is meshed at last. Moreover, meshing is performed in MATLAB and the outer most ring of upper half is represented by first row and outer most ring of lower half is represented by last row. The nodes of each row is created from left to right starting from top row for the outer most ring of upper half.
[0075] In an embodiment, FIG. 13A illustrates an exemplary output mesh for a square pattern at an output plane which is also meshed in same ratio of input plane N x N. The right-side arrow indicates sequence of the mesh creation (i.e. from top row to bottom row).
[0076] In an embodiment, FIG. 13B illustrates an exemplary output mesh for a rhombus pattern at an output plane which is also meshed in same ratio of input plane N x N. In the pattern, right side arrow indicates sequence of mesh creation (i.e., from top row of an upper half to bottom most row of a lower half).
[0077] In an embodiment, FIG. 14A illustrates an exemplary mapping of an output plane for a square pattern with an input plane mesh of Gaussian, where outermost row of an upper half of input mesh (i.e., outer semi-circle of the upper half) is mapped to top most row of output square mesh. Similarly, outer most row of a lower half (i.e., outer semicircle of the lower half) is mapped to bottom most row of square.
[0078] In an exemplary embodiment, numbering and sequence followed in meshing is highly import for Eikonal technique to work. Once the input mesh is created, output mesh is then created following the same sequence used for input mesh creation. Further, output mesh for Square and Rhombus is shown in FIG. 13A and Fig 13B respectively. The nodes of each row is created from left to right starting from the top row, and location position of zones in both the input and output mesh should be as close as possible for Eikonal technique to work. The mapping sequence from input plane mesh to output plane is shown in FIG. 14A.
[0079] In an embodiment, FIG. 14B illustrates an exemplary mapping of an output plane for a rhombus pattern with an input plane mesh of Gaussian, where an outermost row of an upper half of input mesh (i.e., outer semi-circle of the upper half) is mapped to top most row of output square mesh. Similarly, outer most row of a lower half (i.e., outer semicircle of the lower half) is mapped to bottom most row of the rhombus.
[0080] In an embodiment, FIG. 15A illustrates a phase graph with phase values at node points for square output. The phase graph with the phase values at each node points generated by solving the gradient equation for as coordinates from output plane pattern for square.
[0081] In an embodiment, FIG. 15B illustrates a phase graph with phase values at node points for rhombus output, in accordance with an embodiment of the present disclosure. The phase graph with the phase values at each node points generated by solving the gradient equation for as coordinates from output plane pattern for rhombus.
[0082] In an exemplary embodiment, once the input mesh and output mesh is created, phase can be calculated using Eikonal method:
(1)
Where k is the wave vector given by





& d is distance between Image plane and DOE plane, the gradient of the wave is given by
(2)
[0083] A function in terms of gradient of ψ fitted with polynomial is defined in terms of ũ & x(ũ) coordinates and distance "d" as per equation (2). By solving for gradient of , phase values at each node points can be retrieved. FIGs. 15A and FIG. 15B shows the phase plot with respect to each nodes for square and rhombus output respectively.
[0084] In an exemplary embodiment, phase values retrieved are discrete values at the nodes and the nodes are not equidistant. The number of points of nodes will not be sufficient to generate the continuous phase to write the DOE. A lot more evenly spaced points are required to generate the DOE complete phase. Further, simulation and verification of the output can be done with the evenly spaced points by Fourier Transform method. Moreover, the phase value at intermediate equidistant points may be generated using surface fitting command in MATLAB, and surface fitting tool may be used to fit existing data with a polynomial degree of ‘5’. The coefficient obtained from the surface fit is used to generate the phase values at all the intermediate points to get a continuous phase, and the continuous phase profile may be generated using the surface fitting tool for square output and rhombus output is shown in FIGs. 16A and 16B respectively, where FIG. 16A illustrates a phase graph of DOE for square output, for evenly spaced points generated with coefficient obtained from surface fitting tool using the phase graph at node points for square patter, and FIG. 16B illustrates a phase graph of DOE for rhombus output, for evenly spaced points generated with coefficient obtained from surface fitting tool using the phase graph at node points for rhombus pattern.
[0085] In an embodiment, FIG. 17A illustrates an output intensity graph of DOE from Gaussian to Square output using Fourier Transform (FFT) method, where the FFT method is performed on interpolated phase values for square pattern, and output confirms shape of a square and verifies it.
[0086] In an embodiment, FIG. 17B illustrates an output intensity graph of DOE for Gaussian to rhombus output using Fourier Transform (FFT) method, where the FFT method is performed on interpolated phase values for rhombus pattern, and output confirms shape of a rhombus and verifies it.
[0087] In an exemplary embodiment, the continuous phase profile generated output may be verified by applying Fourier Transform method to see the output intensity plot, as shown in FIGs. 17A and 17B, the output intensity plot for both Square pattern and Rhombus pattern respectively.
[0088] Above described embodiments disclose a signaling lamp 100 that uses the multilevel diffractive optical element to produce the necessary output pattern for signaling, also improving the visibility of the vehicle for other drivers, pedestrians, and bicyclists, making it easier for them to understand the vehicle's intentions and respond accordingly. The signaling lamp 100 is designed to be as small as possible, which also reduces the number of components and overall size of the signaling lamp. Additionally, the proposed signaling lamp is lighter in weight and utilizes simpler and more cost-effective methods, which improve its mechanical stability and longevity.
[0089] Moreover, the above-described signaling lamp improves safety by making the vehicle more visible, and helps to reduce risk of accidents and collisions. It is easy to use and requires minimal effort from the driver, making them a convenient safety feature and can last for a long time with proper maintenance.
[0090] In further description of the preferred embodiments of the present invention, the signaling lamp will draw a solid-light pattern onto the targeted area. Individually selected patterns may be carved such as parallelogram, square, circle, rectangle, complex symmetrical polygon, or a combination thereof. This may be accomplished by designing the DOE 106 using the Eikonal technique.
[0091] 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.
[0092] 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.
[0093] 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
[0094] The present disclosure provides a signaling lamp that achieves required output pattern for signaling function using multilevel diffractive optic element
[0095] The present disclosure provides a signaling lamp that increases visibility of the vehicle to other drivers, pedestrians, and bicyclists, making it easier for them to see the vehicle's intentions and react accordingly.
[0096] The present disclosure provides a signaling lamp that uses a diffractive optic element designed by Eikonal method to generate a continuous phase profile.
[0097] The present disclosure provides a signaling lamp that is designed as small as possible, which also decreases number of components and overall size of the signaling lamp.
[0098] The present disclosure provides a signaling lamp that employs a small diffractive optical element to shape the input beam pattern for a specific purpose.
[0099] The Present disclosure helps to realize the signaling function photometry with reduced apparent surface area.
[00100] The present disclosure provides a signaling lamp that is lighter in weight, as it is smaller in size compared to traditional signaling lamps.
[00101] The present disclosure provides a signaling lamp that utilizes simpler or more cost-effective methods and improves the mechanical stability and longevity of the signaling lamp.
[00102] The present disclosure provides a signaling lamp that improved safety by making the vehicle more visible in extreme weather and helps to reduce risk of accidents and collisions.

, Claims:1. A signaling lamp (100) for a motor vehicle comprising:
a light source (102) configured to generate a light beam;
a primary optic element (104) optically connected to the light source, the primary optic element configured to collect the light beam from the light source and collimate the collected light beam; and
a diffractive optical element (DOE) (106) optically connected to the primary optic element, and configured to diffract the collimated light beam on a target plane 108, wherein upon diffraction, the collimated light beam generates one or more pre-defined patterns corresponding to pre-defined photometry requirements for the signaling lamp of the motor vehicle, and wherein the DOE generates the one or more patterns on the target plane.
2. The signaling lamp as claimed in claim 1, wherein, the light source is a polychromatic LED light source.
3. The signaling lamp as claimed in claim 1, wherein, the light source is a narrow linewidth of wavelength with a full width at half maximum (FWHM) of less than or equal to 25-30nm.
4. The signaling lamp as claimed in claim 1, wherein, the primary optic element 104 acts as an collimator and designed to make output profile fitting more closer to Gaussian profile. The signaling lamp as claimed in claim 1, wherein, the one or more pre-defined patterns are selected from a group consisting of parallelogram, square, rectangle, circle, plus sign, symmetrical polygon, symbols
5. The signaling lamp as claimed in claim 1, wherein, the DOE is configured to generate the one or more pre-defined patterns corresponding to type of the signaling lamp, wherein type of the signaling lamp is selected from a group consisting of tail lamp, rear fog lamp, break light, warning lamp ,indicator light, side marker lamp.
6. The signaling lamp as claimed in claim 1, wherein, the DOE is made of a light-transmitting material and segmented into a plurality of pixels, wherein each pixel is associated to a phase value, wherein the phase value is generated by the Eikonal technique corresponding to the one or more patterns required by the motor vehicle.
7. The signaling lamp as claimed in claim 6, wherein, each of the plurality of pixels is designed for a specific wavelength that generates a sharp pattern in the target plane and remaining wavelengths falling on the plurality of pixels creates a blurred pattern on the target plane, wherein combination of the sharp pattern and the blurred pattern defines the required pattern corresponding to pre-defined photometry requirements.
8. The signaling lamp as claimed in claim 7, wherein the DOE facilitates multilevel diffractive element through the Eikonal technique, wherein the generated diffractive element is of a continuous phase profile.
9. The signaling lamp as claimed in claim 1, wherein the input light beam and the generated one or more pre-defined patterns are meshed to obtain a same number of node points and follow a same sequence for creating node points for both input and output mesh, wherein mesh zones of an input plane lies closer to the mesh zones and nodes of the target plane for Eikonal technique.
10. The signaling lamp as claimed in claim 8, wherein, the generated continuous phase profile is verified by Fourier transform method.
11. The signaling lamp as claimed in claim 8, wherein the collimated beam is altered by the plurality of pixels of the DOE by changing phase content of the received collimated beam incident on the DOE, wherein the phase content is altered by changing optical path length to get the continuous phase profile for the required at least one of the one or more patterns.