A monolithicized reflective cavity with built-in diffuse reflection microstructure

Abstract

The utility model belongs to the field of car light illumination, concretely relates to a kind of single-body reflector cavity with built-in diffuse reflection microstructure, including bottom mounting, pcb board, inner reflection component, outer cover and light exit surface, inner reflection component is integrated, inner reflection component rear end is fixed on pcb board, inner reflection component and pcb board are set in bottom mounting interior, bottom mounting front opening and outer cover are fixed in bottom mounting front, outer cover encloses inner reflection component and pcb board in bottom mounting, light exit surface is set in the front of outer cover, inner reflection component middle is provided with several cavities, cavity is set as curved surface bowl shape and several cavities are connected, cavity front and rear are all open, LED light source on pcb board is located at cavity rear opening, cavity inner wall is provided with several pits or protrusions, outer cover is transparent and light directly emits from outer cover.

Description

Technical Field

[0001] This utility model belongs to the field of vehicle lighting, specifically relating to a monolithic reflective cavity with a built-in diffuse reflection microstructure. Background Technology

[0002] The prior art includes patent CN120488165A, which discloses an optical structure for automotive lights, mainly comprising: a thick-walled structure composed of multiple thick-walled units, each unit having multiple reflective surfaces and one light-emitting surface; a light-concentrating structure embedded inside each thick-walled unit, used to initially converge the light emitted by the light source; and a diffuse reflection pattern structure set on the reflective surface, used to scatter the light after it has been concentrated.

[0003] The light from the light source is focused by the light-concentrating structure, then scatters on the reflective surface with a diffuse reflection pattern before exiting from the light-emitting surface; the diffuse reflection pattern expands the light emission angle, achieving a wider illumination range.

[0004] There is also a patent: CN115707903A, which discloses a vehicle lighting assembly with a reflector system and a light emitter, mainly including: a reflector system: a corrugated collimator (which can be made of flexible or rigid material) composed of multiple grooves, used to collimate the light emitted by the light source; a light emitter: an LED light source integrated in the reflector system, providing initial illumination light; and a textured lens: covering the surface of the cavity formed by the reflector system, the surface of which is provided with a specific texture.

[0005] After the light from the light source is collimated by the corrugated collimator of the reflector system, it is directed onto the textured surface of the lens and then emitted from the lens after being scattered by the texture. Through the combined design of "collimation + texture scattering", a wider and more uniform vehicle illumination range is achieved.

[0006] However, the above-mentioned existing technologies have the following drawbacks: 1. Large number of parts: The reflector and the diffuser need to be injection molded and assembled separately, which increases the BOM cost and assembly tolerance risk; 2. Loss of optical efficiency: Regardless of the scheme, the light needs to pass through the diffuser again after passing through the reflector, resulting in Fresnel reflection and volume absorption, which reduces the light efficiency by about 15-20%. Utility Model Content

[0007] To address the aforementioned problems in the existing technology, this utility model provides a modular reflective cavity with a built-in diffuse reflection microstructure, which simplifies the system structure and improves optical performance.

[0008] To achieve the above objectives, this utility model provides the following technical solution: a monolithic reflective cavity with a built-in diffuse reflection microstructure, comprising a bottom mounting component, a PCB board, an inner reflector, an outer cover, and a light-emitting surface. The inner reflector is integral, with its rear end fixed to the PCB board. The inner reflector and the PCB board are disposed inside the bottom mounting component. The bottom mounting component has an opening at the front, and the outer cover is fixed to the front of the bottom mounting component. The outer cover encloses the inner reflector and the PCB board within the bottom mounting component. The light-emitting surface is disposed in front of the outer cover. The inner reflector has several cavities in its middle, each cavity being a curved bowl shape and connected to the others. Both the front and rear of the cavities are open. The LED light source on the PCB board is located at the rear opening of the cavity. The inner wall of the cavity has several pits or protrusions. The outer cover is transparent, and light is emitted directly from the outer cover.

[0009] Furthermore, the shape of the pits or protrusions on the cavity is set as a freeform surface similar to an ellipsoid with continuously varying curvature.

[0010] Furthermore, the inner surface of the cavity is a parabola, and the LED light source is located at the focal point of the inner surface of the cavity.

[0011] Furthermore, the light emitted by the LED light source is reflected more than twice in the pits or protrusions to achieve Markov chain randomization of the light direction, and the angle of the emitted light is in the range of 0° to 90°. The single-point reflected light rays incident on the pits or protrusions of the LED light source are discrete.

[0012] Furthermore, the arrangement of several pits or protrusions on the inner surface of the cavity gradually transitions from sparse to dense, and their size gradually transitions from small to large, from near to far from the LED light source.

[0013] Furthermore, the density of pits or protrusions is ≥20 per mm2, the pit depth is 50μm~80μm and the width is 100μm~150μm, or the protrusion height is 50μm~80μm and the width is 100μm~150μm, and the ratio of the major axis to the minor axis of the pits or protrusions is 0.7~0.9.

[0014] Furthermore, the cavity material uses PMMA, PC and TiO2 or BaSO4, or a high-reflectivity diffuse reflection coating is deposited on the inner surface of the cavity.

[0015] Furthermore, the cavity shape can be any one of spherical, cylindrical, and curved bowl shape. The axial direction of the cavity is consistent with the main optical axis of the LED light source. The inner wall of the cavity is provided with any one of micro pyramids, pyramids, pits, and protrusions. The height of the micro pyramids or pyramids is 50μm to 100μm, and the angle between the axis of the micro pyramids or pyramids and the axis of the cavity is 45° to 90°.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] 1. Adopting an integrated cavity structure: The internal reflector adopts a rear mounting surface, and the cavity (rotationally symmetric or free-form surface) is designed with continuous sidewalls. Only the light outlet is covered by an outer cover without diffusion function, which can eliminate splicing seams and improve light efficiency.

[0018] 2. Microstructure geometry: Each pit or protrusion on the cavity is a free-form surface of ellipsoidal shape with continuous curvature (non-spherical, non-cylindrical, non-random rough surface), thus ensuring that each reflection is still a specular reflection, which is highly controllable and reduces energy loss.

[0019] 3. Combination of spatial arrangement: The microstructure of each pit or protrusion has a local normal that is statistically randomly distributed in space (non-periodic and irregular), which makes the direction of the incident light highly discrete after one or more reflections, and is macroscopically equivalent to a Lambertian volume.

[0020] 4. Simplified system structure: Completely eliminates independent diffusion components (such as diffusion plates and diffusion films), simplifying the optical system structure and reducing assembly complexity and cost;

[0021] 5. Improved optical performance: Light is directly homogenized inside the cavity, reducing Fresnel reflection loss caused by traditional multi-layer structure interfaces, which helps to improve light energy utilization efficiency. By optimizing the cavity shape and the microstructure parameters of pits or protrusions, effective control of the light output angle distribution can be achieved.

[0022] 6. Application potential: It can be widely used in fields with high requirements for illumination uniformity, such as high-end uniform surface light sources: such as for photographic fill light, microscope illumination and other applications requiring shadowless uniform illumination. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of this utility model;

[0024] Figure 2 This is an exploded view of the present invention;

[0025] Figure 3 for Figure 1 Sectional view at point AA;

[0026] Figure 4 This is an assembly drawing of the internal reflector and PCB board of this utility model;

[0027] Figure 5 for Figure 4 Sectional view at point BB;

[0028] Figure 6 This is a schematic diagram of the internal reflector of this utility model being assembled with the PCB board into the bottom mounting component.

[0029] Figure 7This is a light ray trend diagram of the present invention;

[0030] Figure 8 This is a schematic diagram of the microstructure of the cavity of this utility model;

[0031] Figure 9 This is a graph showing the gradient density distribution of the pits on the cavity of this utility model.

[0032] Figure 10 This is a test diagram of the light output pattern of this utility model and a comparison diagram of the standard Lambertian light source. Detailed Implementation

[0033] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0034] Please see Figure 1-7The technical solution provided by this utility model is as follows: a modular reflective cavity with a built-in diffuse reflection microstructure, including a bottom mounting component 1, a PCB board 2, an inner reflector 3, an outer cover 4, and a light-emitting surface 5. The bottom mounting component 1 has an opening on one side and is internally cavity-shaped. The opening side of the bottom mounting component 1 is set horizontally or inclined, which is set according to the design requirements of the car headlight. The inner reflector 3 is integrally manufactured as a modular structure by injection molding or hot pressing. The rear end of the inner reflector 3 is fixed to the four corners of the PCB board 2 by screws 7. The inner reflector 3 and the PCB board 2 are set in the cavity inside the bottom mounting component 1, and the upper part of the inner reflector 3 is fixed to the bottom mounting component 1 by screws 7. The bottom mounting component 1 has an opening at the front, and the outer cover 4 is fixed to the opening at the front of the bottom mounting component 1 by welding. The outer cover 4 encloses the inner reflector 3 and the PCB board 2 inside the bottom mounting component 1. The light-emitting surface 5 is set... In front of the outer cover 4, the light-emitting surface 5 is used to receive the light emitted from the outer cover 4. The lower part of the light-emitting surface 5 is set as an arc surface, which is the part that is directly visible from the front of the headlight. The inner reflector 3 has several cavities 31 in the middle. The cavities 31 are set as curved bowls and several cavities 31 are connected to each other. The front and rear of the cavities 31 are open. The connection between the cavities 31 is from any position on the body of the cavity 31. The LED light source 6 on the PCB board 2 is located at the rear opening of the cavity 31. Each cavity 31 has an LED light source 6 at the rear opening. The inner wall of the cavity 31 is provided with several pits or protrusions. The side wall of the cavity 31 and the surface of several pits or protrusions together form a continuous inner reflective surface. The whole is rotationally symmetrical or free-form surface. The light outlet is located at the front and the top and bottom sides of the cavity 31. The outer cover 4 is transparent and the light is emitted directly from the outer cover 4. The outer cover 4 does not have an optical diffusion function. The light emitted by the LED light source 6 is directed into the cavity 31. After multiple reflections on the inner reflective surface of the cavity 31, the light is emitted from the outer cover 4. The light-emitting surface 5 then receives the light emitted from the outer cover 4. The light is directly homogenized inside the cavity 31, completely eliminating the need for a separate diffusion component. This reduces Fresnel reflection losses caused by traditional multi-layer interfaces and helps improve light energy utilization efficiency.

[0035] Specifically, the shape of the pits or protrusions on cavity 31 is set as a freeform surface of quasi-ellipsoidal shape with continuously varying curvature, and its local normals are statistically randomly distributed in space. For example... Figure 7 As shown, when light emitted from LED light source 6 is incident on any pit or protrusion on the inner wall, it undergoes one or more specular reflections based on the local normal at that point; for example... Figure 10As shown, due to the spatial randomness and diverse curvature directions of the random array of pits or protrusions, the direction of the outgoing light rays is effectively randomized, and macroscopically it exhibits the diffuse reflection characteristics of an approximate Lambertian body, that is, the outgoing radiation intensity satisfies I(θ)=I0*cosθ, where θ is the angle between the outgoing light ray and the axis (normal) of cavity 31.

[0036] Specifically, such as Figure 8 As shown, the inner surface of the cavity 31 is a parabolic surface, and the LED light source 6 is located at the focal point of the inner surface of the cavity 31. This arrangement is used to efficiently collect the light emitted by the LED light source 6 and guide it to be incident on a random array of pits or protrusions.

[0037] Specifically, due to the diversity of local normals on the surface of the random pit or protrusion array microstructure, the light emitted by the LED light source 6 is reflected more than twice in the pits or protrusions, achieving Markov chain randomization of the light direction. The initial incident direction information is basically lost, and the angle of the outgoing light is in the range of 0° to 90°, achieving phase space homogenization. The single-point reflected light rays incident on the pits or protrusions of the LED light source 6 are discrete. This is because a single ellipsoidal pit or protrusion, as a free-form surface reflection unit, decomposes the incident light into different directions according to the law of reflection. Due to the continuous curvature change of the ellipsoidal surface, the local normals of different points in the same pit are different, resulting in slight discreteness in the direction of the single-point reflected light.

[0038] Specifically, the arrangement of several pits or protrusions on the inner surface of the cavity 31 gradually transitions from sparse to dense, and their size gradually increases from small to large, from near to far from the LED light source 6. The spatial density of the array unit pits or protrusions is gradient-distributed along the light propagation direction from the LED light source 6 to the array surface—that is, the unit density is lower (sparse) on the incident side near the LED light source 6 and higher (dense) on the side far from the LED light source 6. This reduces ineffective multiple reflections of light in the array (weak light does not need repeated scattering), retains more effective light, and improves luminous efficiency; the size also changes gradually. The sparseness on the incident side reduces unnecessary multiple reflections, while the density on the exiting side captures more weak light after the first reflection (which might otherwise escape from the cavity 31), improving the utilization rate of weak light.

[0039] like Figure 9 As shown, the gradient density distribution with sparser areas near the center and denser areas far away is as follows: Let N(z) be the density per unit area of ​​the array cells along the z-axis (direction of light propagation), where N(z) (i.e., the number of pits or bumps per square millimeter). The gradient design with sparser areas near the center and denser areas far away can be expressed as an exponentially decaying gradient (or a linear gradient, depending on the manufacturing difficulty): N(z) = N0·e -αZ

[0040] Where: N0: unit density (sparse end) on the light source side (z=0);

[0041] α: Gradient decay coefficient (α>0, controls the rate of density change);

[0042] Specifically, the parameters of the random array of pits or bumps satisfy:

[0043] Density ≥ 20 particles / mm²;

[0044] The pit has a depth of 50μm to 80μm and a width of 100μm to 150μm, or the protrusion has a height of 50μm to 80μm and a width of 100μm to 150μm, and the ratio of the major axis to the minor axis of the pit or protrusion is 0.7 to 0.9.

[0045] Specifically, the material of cavity 31 is selected from high-reflectivity polymers, which can be achieved in two ways: one is to use white engineering plastics made of PMMA, PC, and TiO2 or BaSO4 diffuse reflective particles, with an overall reflectivity ≥80%; the other is to coat the inner surface of cavity 31 with a high-reflectivity diffuse reflective coating, including... Or its equivalent material, the coating itself has Lambertian reflective properties.

[0046] Specifically, the random pit or protrusion array is a continuous ellipsoidal structure, which is prepared by microimprinting. This involves pressing a heated and softened polymer substrate with a silicon mold bearing an ellipsoidal microstructure pattern, cooling and shaping it, and then demolding it to form an inner wall microstructure that complements the mold pattern.

[0047] The integrated diffuse reflection optical cavity 31 of this invention is structurally equivalent to an "expanded integrating sphere." By replacing the diffuse reflection coating of a traditional integrating sphere with a random array of pits or protrusions on its inner wall, it significantly shortens the optical path, reduces absorption loss, and improves the system's luminous efficiency while maintaining near-Lambertian light emission characteristics. The light outlet, i.e., the opening at the front of the cavity 31, contains no optical diffusion elements. The uniformity of the emitted light is entirely achieved by the random array of pits or protrusions on the inner wall of the cavity 31 through multiple mirror reflections and local normal randomization, thereby avoiding the ≥30% light energy loss caused by traditional diffusers.

[0048] Other embodiments of this utility model are as follows:

[0049] Macroscopic cavity: In addition to the curved bowl shape, the shape of cavity 31 can also be either spherical or cylindrical. Its axis is consistent with the main optical axis of LED light source 6, which is used to guide the light to reflect multiple times along a predetermined path inside cavity 31 and finally escape from the light outlet.

[0050] Microstructure: In addition to pits or protrusions, the inner wall of cavity 31 can also be formed with any one of micro pyramids or pyramids. The height of the micro pyramids or pyramids is 50μm to 100μm, the base shape is square or hexagonal, and the angle between the axis of the micro pyramid or pyramid and the axis of cavity 31 is 45° to 90°. The parameter settings of any one of the pits, protrusions, micro pyramids, and pyramids in this invention are random, and the parameters of each pit, protrusion, micro pyramid, and pyramid can be set differently.

[0051] The optical principle of this invention is as follows: the light emitted by the LED light source 6 is directed into the cavity 31. After multiple reflections on the inner reflective surface of the cavity 31, the light is emitted from the outer cover 4. Then, the light-emitting surface 5 receives the light emitted from the outer cover 4. The light is directly homogenized inside the cavity 31, completely eliminating the need for independent diffusion components, reducing Fresnel reflection losses caused by traditional multi-layer interfaces, and helping to improve light energy utilization efficiency.

[0052] Finally, it should be noted that the above are merely preferred embodiments of this utility model and are not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A modular reflective cavity with a built-in diffuse reflection microstructure, characterized in that, The device includes a bottom mounting component (1), a PCB board (2), an inner reflector (3), an outer cover (4), and a light-emitting surface (5). The inner reflector (3) is integral, and its rear end is fixed to the PCB board (2). The inner reflector (3) and the PCB board (2) are disposed inside the bottom mounting component (1). The bottom mounting component (1) has an opening at the front, and the outer cover (4) is fixed to the front of the bottom mounting component (1). The outer cover (4) encloses the inner reflector (3) and the PCB board (2) within the bottom mounting component. Inside component (1), the light-emitting surface (5) is located in front of the outer cover (4). The inner reflector (3) has several cavities (31) in the middle. The cavity (31) is set as a curved bowl shape and several cavities (31) are connected. The cavity (31) is open at both the front and back. The LED light source (6) on the PCB board (2) is located at the back opening of the cavity (31). The inner wall of the cavity (31) is provided with several pits or protrusions. The outer cover (4) is transparent and the light is emitted directly from the outer cover (4).

2. The modular reflective cavity with a built-in diffuse reflection microstructure according to claim 1, characterized in that, The shape of the pits or protrusions on the cavity (31) is set as a free-form ellipsoidal surface with continuously varying curvature.

3. A modular reflective cavity with a built-in diffuse reflection microstructure according to claim 2, characterized in that, The inner surface of the cavity (31) is a parabola, and the LED light source (6) is located at the focal point of the inner surface of the cavity (31).

4. A modular reflective cavity with a built-in diffuse reflection microstructure according to claim 3, characterized in that, The light emitted by the LED light source (6) is reflected more than twice in the pit or protrusion to achieve Markov chain randomization of the light direction. The angle range of the emitted light is 0° to 90°. The single-point reflected light incident on the pit or protrusion by the LED light source (6) is discrete.

5. A modular reflective cavity with a built-in diffuse reflection microstructure according to claim 4, characterized in that, The arrangement of the pits or protrusions on the inner surface of the cavity (31) gradually transitions from sparse to dense and from close to far away from the LED light source (6), and their size gradually transitions from small to large.

6. A modular reflective cavity with a built-in diffuse reflection microstructure according to claim 5, characterized in that, The density of the pits or protrusions is ≥20 per mm2, the pit depth is 50μm~80μm and the width is 100μm~150μm, or the protrusion height is 50μm~80μm and the width is 100μm~150μm, and the ratio of the major axis to the minor axis of the pits or protrusions is 0.7~0.

9.

7. A modular reflective cavity with a built-in diffuse reflection microstructure according to claim 6, characterized in that, The cavity (31) is made of PMMA, PC and TiO2 or BaSO4, or a high reflectivity diffuse reflection coating is deposited on the inner surface of the cavity (31).

8. A modular reflective cavity with a built-in diffuse reflection microstructure according to any one of claims 1-7, characterized in that, The cavity (31) can be any one of spherical, cylindrical and curved bowl shape. The axial direction of the cavity (31) is consistent with the main optical axis of the LED light source (6). The inner wall of the cavity (31) is provided with any one of micro pyramid, pyramid, pit and protrusion. The height of the micro pyramid or pyramid is 50μm to 100μm and the angle between the axis of the micro pyramid or pyramid and the axis of the cavity (31) is 45° to 90°.

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