Lens for LED light source vehicle lamp

Abstract

The present invention relates to a beam-splitting lens for generating a multi-beam light emitter, said beam-splitting lens comprising at least two single lenses, each single lens being capable of projecting a collimated light beam from light captured at a focal point defined by the configuration of the lens, each single lens being configured so as to have its own individual focal point which is different from the individual focal point of the other lens.

Description

Technical Field

[0001] This invention generally relates to the field of vehicle lighting systems, and more specifically to techniques for generating headlight beams. Background Technology

[0002] In road lighting systems, lenses are typically used to perform a spreading function. For traffic lights, the spreading and defocusing functions of lenses are used to improve the uniformity of the luminaire.

[0003] In existing solutions, none of them utilize the surface characteristics of the light source when applicable, unlike point light sources.

[0004] In fact, light-emitting diodes (LEDs) do have a light-emitting surface, but this surface is usually considered to be transient.

[0005] The inventors intended to utilize the fact that LEDs are not point-like. Instead, LEDs have a light-emitting surface, typically a square or rectangular one. Furthermore, emerging matrix technology provides light sources composed of LED matrices, which obviously also provide surface light sources.

[0006] Therefore, the inventors believe that it is worthwhile to consider surface light sources to feed beam splitters in order to obtain multiple high-quality beams from a single light source.

[0007] US8007154B2 discloses a vehicle lamp comprising four LED light sources and four parabolic reflectors. The lamp includes a lens with multiple cutouts configured to diffuse a light beam from the light sources via the parabolic reflectors. The incident surface of the lens is convex. In one embodiment, the lens includes four cutouts for diffusing the light beam from the four light sources via the parabolic reflectors. The light emitted by the LEDs is paralleled by the parabolic reflectors before reaching the lens. At the lens exit point, the light diverges to achieve the desired enhanced light diffusion effect. This known solution cannot be used to produce a headlight beam because such a beam must be collimated. Furthermore, the arrangement of the LEDs and parabolic mirrors is quite bulky.

[0008] Furthermore, in US8007154B2, the LEDs are not arranged to form a surface light source, nor do they form an LED matrix. Therefore, this prior art document does not contribute to the advancement of promising matrix technology.

[0009] To achieve a collimated beam distribution, especially for headlights with kink beams and high beam constraints, multiple central lenses and multiple light sources are required, resulting in a rather bulky headlight housing that cannot be integrated into a so-called "ultra-thin linear" module.

[0010] In fact, there is a need for a matrix projection device whose height does not exceed a certain dimension, such as 10 mm. Summary of the Invention

[0011] One object of the present invention is a beam-splitting lens for generating a multi-beam emitter, the beam-splitting lens comprising at least two simple lenses, each capable of projecting a collimated beam of light captured at a corresponding focal point, hereinafter referred to as an "individual focal point" and defined by the construction of the lens.

[0012] According to the present invention, each single lens, which is a component of a beam-splitting lens, is configured to have its own individual focal point, and its individual focal point is different from the individual focal point of another lens.

[0013] An important feature of this invention is that the individual lenses of the beam-splitting lens do not share the same individual focal point.

[0014] According to the present invention, each single lens is configured such that its individual focal point is different from that of another single lens of the beam-splitting lens, such that the distance between adjacent individual focal points is minimized.

[0015] The beam-splitter lens of this invention is an optical element that replaces the central lens commonly used in LED collimators. It allows for precise control of the collimated beam, making it a suitable component of LED collimators used in matrix projection device designs. This collimator can also serve as a primary optics element in ultra-thin headlight modules.

[0016] The technical advantages of this invention include: because the individual focal points are different from each other, each single lens projects its own beam forward without being disturbed by neighboring lenses. The minimum distance between two individual focal points is a key factor in ensuring optimal performance and minimizing interference noise between beams from neighboring lenses.

[0017] The minimum distance between individual focal points can vary depending on factors such as wavelength, beam angle, and desired system performance characteristics; for example, in visible light applications of approximately 550–650 nm, this distance may be 1.5 mm.

[0018] In a preferred embodiment, the minimum distance between individual focal points is greater than or equal to one dimension of the emitting surface size. For example, when using surface-emitting LEDs (SELEDs) with emitting surface dimensions in the range of 0.5 to 3.0 mm, the minimum distance between individual focal points can be configured to be approximately 25% of that value, typically in the range of 25% to 500%.

[0019] In a preferred embodiment, the individual focus of each single lens can be adjusted according to the requirements of a specific application to achieve a greater distance. This greater distance allows for greater flexibility in the design of the beam-splitter lens configuration, but may increase the overall size and complexity. Generally, for visible light applications with wavelengths of approximately 550-650 nm, the applicable distance range is from a few tenths of a millimeter to tens of millimeters.

[0020] In a preferred embodiment, for example, when designing a beam-splitting lens using a SELED with dimensions of approximately 1.5 mm for the length and width (i.e., rectangular shape) of the luminescent surface, the minimum distance between focal points can be set to approximately 2.0 mm. This allows adjacent beams to be separated sufficiently while maintaining a compact design suitable for road lighting applications.

[0021] In one particular embodiment, the distance can be determined using a formula. The formula may be:

[0022] [Formula 1]

[0023] d y = SeparationCoeficient y × L y

[0024] d z = SeparationCoeficient z × L z

[0025] in:

[0026] d y and d z These are the distances between the individual focal point and the light source focal point in the Y and Z directions, respectively, in mm;

[0027] Separation Coeficient y and SeparationCoeficient z These are the scaling factors in the Y and Z directions, respectively, represented by % and greater than or equal to 25% and less than 250%;

[0028] L y and L z These are the dimensions of the luminescent surface in the Y and Z directions, respectively, in mm.

[0029] In one particular embodiment, each single lens is designed to have its individual focal point outside the emitting surface to allow for optimal reduction of interference.

[0030] According to a particular embodiment, the beam-splitting lens comprises two or four single lenses with asymmetric properties, which are adapted to produce collimated beams.

[0031] In one particular embodiment, at least one surface of the single lens has an aspherical shape having at least one vertex located on the surface of the single lens. For example, the aspherical shape may be selected from the following list: hyperboloid, paraboloid, and elliptical surface.

[0032] Preferably, when the number of vertices is greater than or equal to four, all vertices lie on the same plane.

[0033] The present invention assumes that the number of vertices in the beam-splitter lens located on a surface configured to receive light emitted from an LED is equal to the number of single lenses that are components of the beam-splitter lens.

[0034] Compared with traditional single-focus lenses, the advantages of this invention include:

[0035] a) Increase lighting efficiency by 190% to 370% in projection systems;

[0036] b) The dimensions of the real light source are taken into account, including the size of the LED light source and the size of the LED chip (not considered as a point), thereby reducing the sensitivity to the position of the LED;

[0037] c) Two or more divergent collimated beams can be obtained;

[0038] d) By appropriately designing a suitable single lens, the diverging beam can be controlled independently;

[0039] e) By separating individual focal points, the optical noise of the system is reduced, i.e., interference from adjacent beams is reduced.

[0040] In one particular embodiment, adjacent beams diverge with an angular spread ranging from 2 to 25 degrees, thereby allowing for non-overlapping and efficient light distribution.

[0041] In one particular embodiment, the beam-splitting lens includes at least two single lenses (3a, 3b, 3c, 3d; 25a, 25b), each lens having an independently designed optical surface configured to generate beams with different propagation directions and predetermined beam divergences.

[0042] The fact that the generated beams have different propagation directions means that they are not guided along the same axis, but rather diverge from each other.

[0043] Beam divergence is a measure of how much a beam of light spreads outward as it propagates from the aperture of an optical system. It is expressed as an angle, typically in the range of 1 to 10 degrees, representing the angle between the outermost rays of the beam.

[0044] In a further embodiment, a specialized coating can be applied to specific wavelengths to enhance performance. For example, a UV-protective coating can enhance LED chip efficiency, while an anti-reflective coating can reduce losses caused by internal reflections within the composite lens system. The material of the light-emitting surface is preferably selected from LEDs with high luminous efficiency and low spectral variation, such as SELEDs. The choice of material used to construct each individual lens can vary depending on factors such as cost-effectiveness and compatibility with other components. Generally, glass materials such as BK7 are a suitable choice due to their refractive index and optical properties. Other suitable materials include polycarbonate, polymethyl methacrylate, polyethylene terephthalate, polymethacrylamide, and liquid silicone rubber.

[0045] Some advantages of the beam-splitting lens according to the present invention are:

[0046] a) Obtain four or two collimated beams from a single LED;

[0047] b) Make the quadrature beam splitter addressable;

[0048] c) Enables asymmetric extension;

[0049] d) Provide uniform illumination, especially a rectangular light distribution.

[0050] In manufacturing, tolerances are considered through design margins during assembly production, such as curvature tolerance (nominal value ±1-5%) and center deviation relative to the ideal position (100-500 μm). Individual focus can be adjusted to optimize beam quality according to specific application requirements, such as in automotive applications demanding high precision and accuracy.

[0051] Thanks to this invention, manufacturing tolerances for each component can be accounted for by designing sufficient margins during production assembly. For example, the curvature tolerance of a lens is ±1-5% of the nominal value, and the center deviation relative to the ideal position is 100-500 μm.

[0052] Regarding the type of LED that can be preferably used in conjunction with the beam-splitting lens of the present invention, the composite lens can be designed using different LED technologies with high luminous efficiency and low spectral variation, such as SELED or microlens arrays on the luminescent surface.

[0053] In one embodiment, a surface-emitting LED (SELED) is used as the light source, the SELED comprising a light-emitting surface facing a single lens designed to have an angular extension range between 2 and 25 degrees to achieve optimal overlap reduction and minimal noise generation.

[0054] Another embodiment employs a microlens array or diffractive optics on the SELED chip to optimize aberrations and collimation efficiency while maintaining a compact design suitable for industrial applications such as vehicle headlights that generate rectangular composite beams. Attached Figure Description

[0055] To facilitate understanding of the present invention, several embodiments will now be described in conjunction with the following accompanying drawings. These embodiments should not be construed as limiting the scope of protection. Where a feature of one embodiment can obviously be combined with a feature of another embodiment, such combination is also implied as part of this specification.

[0056] In the attached image:

[0057] - Figure 1 This is a perspective view of the coupling surface of the beam-splitting lens according to the first embodiment of the present invention;

[0058] - Figure 2 yes Figure 1 Front view of a beam-splitting lens;

[0059] - Figure 3 It is the light source and Figure 1 A perspective view of the coupling surface;

[0060] - Figure 4 yes Figure 3 A close-up view;

[0061] - Figure 5 Show Figure 1 The reverse tracing diagram of the beam-splitting lens;

[0062] - Figure 6 This is a diagram showing the brightness intensity distribution of the beam-splitting lens;

[0063] - Figure 7 This is a diagram showing the brightness intensity distribution achievable through four zones with independent addressing of the light source;

[0064] - Figure 8 This is a graph showing the achievable brightness intensity distribution when all beams are focused;

[0065] - Figure 9 This is a diagram showing the brightness intensity distribution achievable through an asymmetric extended beam;

[0066] - Figure 10 A beam-splitting lens according to a second embodiment of the present invention is shown;

[0067] - Figure 11 Show Figure 10 Front view of a beam-splitting lens;

[0068] - Figure 12 Show Figure 10 The reverse tracking diagram of the beam-splitting lens. Detailed Implementation

[0069] The general principle of constructing the beam-splitting lens of the present invention is to determine the vertex position of the individual focal point of each single lens.

[0070] In the accompanying drawing, the beam-splitting lens 1 is made of polyethylene terephthalate and has a coupling surface 3 designed to receive light from a localized light source. The coupling surface 3 is divided into four quarters 3a, 3b, 3c, and 3d. The central axis 5 of the beam-splitting lens 1 is located at the intersection of the dividing lines 7 of these quarters. Near the central axis 5, each quarter 3a, 3b, 3c, and 3d has vertices 9a, 9b, 9c, and 9d.

[0071] The shape of the single lens in each of the four zones is defined by optical characteristics that depend on the location of the light source. For example... Figure 3 and Figure 4 As shown, the light source is an LED 11 assembled on a chip, having an anode pad 13, a cathode pad 15, and a thermal pad 17.

[0072] Each individual focus 4a, 4b, 4c, 4d corresponding to the four sections 3a, 3b, 3c, 3d of coupling surface 3 is located on the same plane close to the light-emitting surface of LED 11. Each individual focus is different from the other focuses, such that the distance d between adjacent focuses is minimized. y 19 and d z 21. The minimum distance between focal points can be calculated using the formula above.

[0073] LED 11 has a rectangular light-emitting surface that is positioned opposite to the coupling surface 3 of the beam-splitting lens 1, and is used in a headlight device (not shown).

[0074] like Figure 2 As shown, in the X, Y, Z coordinate system with the center of LED 11 as the origin, the coordinates of the individual focus depend on the size of LED 11, the characteristics of LED 11, and the possible displacement of LED 11.

[0075] Basically, the center of LED 11 is aligned with the central axis 5 of beam-splitting lens 1. The shapes of the four sections 3a, 3b, 3c, and 3d of beam-splitting lens 1 ensure that their individual focal points 4a, 4b, 4c, and 4d lie within the plane of the light-emitting surface of LED 11, but not at the center of LED 11. These individual focal points are offset from the center in the Y and Z planes and are located at different positions. Therefore, a distance d exists between any two individual focal points. y 19. d z 21. Consider one dimension L of the luminescent surface, and a distance d. y 19 and d z 21 have the same order of magnitude.

[0076] Each surface in the four partitions 3a, 3b, 3c, and 3d is a coupled surface of a single lens and is created in its local coordinate system. The resulting surfaces are independent of each other.

[0077] exist Figure 5 In the image, the primary conical beam 23 can be seen passing through the beam-splitting lens 1. This beam is split into four non-overlapping beams 23a, 23b, 23c, and 23d.

[0078] exist Figure 6 In this system, each beam has a uniform brightness and is protected from interference from other beams.

[0079] exist Figure 7 In this design, the beams are asymmetrical. This stems from the independent design of each of the four zones.

[0080] exist Figure 8 In the image, four beams are intentionally overlapped, with each beam having the same extent of spread.

[0081] exist Figure 9 In the process, due to the asymmetrical expansion of different beams, the overall beam intensity decreases from the center to the edge.

[0082] Figure 10 and Figure 11 Another embodiment is shown, wherein the beam-splitting lens 25 is divided into two half-regions 25a and 25b, which are separated by a dividing line 27 and have two vertices 29a and 29b. Each single lens has vertices 29a and 29b and individual focal points 4a and 4b on the coupling surface.

[0083] like Figure 12 As shown, the beams 31a and 31b emitted by the beam-splitting lens 25 do not overlap. The same combination of beam-splitting lenses used in the first embodiment is also applicable to the second embodiment.

[0084] List of reference numerals

[0085] 1: Beam-splitter lens

[0086] 3: Coupling surface

[0087] 3a, 3b, 3c, 3d: Four-partition

[0088] 4a, 4b, 4c, 4d: Individual Focus

[0089] 5: Central axis

[0090] 7: Quarterly Boundary Line

[0091] 9a, 9b, 9c, 9d: Vertices

[0092] 11: LED

[0093] 13: Anode pads

[0094] 15: Cathode pad

[0095] 17: Hot solder pad

[0096] 19:d y

[0097] 21:d z

[0098] 23: Primary Conical Beam

[0099] 23a, 23b, 23c, 23d: Beam splitting of the primary conical beam 23

[0100] 25: Beam-splitter lens

[0101] 25a, 25b: Half zone

[0102] 27: Half-district boundary line

[0103] 29a, 29b: Vertex

[0104] 31a, 31b: Beam

Claims

1. A beam-splitting lens (1; 25) for generating a multi-beam emitter, the beam-splitting lens comprising at least two single lenses (3a, 3b, 3c, 3d; 25a, 25b), each single lens being capable of projecting a collimated beam (23a, 23b, 23c, 23d; 31a, 31b) from light captured at a focal point defined by the construction of the single lens. Its features are, Each single lens is constructed to have its own individual focal point (4a, 4b, 4c, 4d), which is different from the individual focal point of another lens, such that the distance between adjacent focal points is minimized (d).

2. The beam-splitting lens according to claim 1, wherein the minimum distance (d) between individual focal points i The value is greater than or equal to 25% of one dimension (L) of the size of the light-emitting surface.

3. The beam-splitting lens according to any of the preceding claims, wherein the distance is determined using the following formula: d y = SeparationCoeficient y × L y d z = SeparationCoeficient z × L z in: d y and d z These are the distances between the individual focal point and the light source focal point in the Y and Z directions, respectively, in mm; Separation Coeficient y and SeparationCoeficient z These are the scaling factors in the Y and Z directions, respectively, represented by % and greater than or equal to 25% and less than 250%; L y and L z These are the dimensions of the light-emitting surface in the Y and Z directions, respectively, in mm.

4. The beam-splitting lens according to any of the preceding claims, wherein the beam-splitting lens comprises two or four single lenses (3a, 3b, 3c, 3d; 25a, 25b) having asymmetric properties adapted to produce collimated beams (23a, 23b, 23c, 23d; 31a, 31b).

5. The beam-splitting lens according to the preceding claim, wherein at least one of the single lenses has an aspherical surface having at least one vertex (9a, 9b, 9c, 9d; 29a, 29b), the vertex of the aspherical surface being located on the surface of the single lens.

6. The beam-splitting lens according to any of the preceding claims, wherein adjacent beams diverge with an angular spread ranging from 2 to 25 degrees.

7. The beam-splitting lens according to any of the preceding claims, wherein the beam-splitting lens comprises at least two single lenses (3a, 3b, 3c, 3d; 25a, 25b), each single lens having an independently designed optical surface configured to generate beams having different propagation directions from each other and having a predetermined beam divergence.

8. A multi-beam emitter, comprising a light source having a light-emitting surface and a beam-splitting lens according to the preceding claims.

9. A vehicle headlight comprising a multi-beam emitter according to the preceding claim.

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