Automotive light guide tail end reflection structure

Abstract

The utility model relates to the technical field of automobile parts production, and specifically discloses an automobile light guide tail end reflection structure, comprising a light guide, a connecting body and a spherical mirror, the utility model is novel in conception, scientific in design, safe and reliable in use, realizes the dual function of light energy recycling and thermal management, compared with the traditional plane mirror technical scheme, can reflect the light guide end stray light back into the light guide efficiently, while significantly improving the light utilization efficiency, the tail end gathered heat will also reduce, reduces the local heat flux density, thereby reduces the thermal management cost, adopts the optimized curvature radius spherical mirror structure and can effectively improve the light efficiency, reduces the light guide end peak temperature delta T degree C, simultaneously reduces the system to high -power light source dependence, reduces the system manufacturing cost and operation cost as a whole.

Description

Technical Field

[0001] This utility model relates to the field of automotive parts manufacturing technology, specifically to an automotive light guide tail end reflection structure. Background Technology

[0002] Light guide technology, as a core means of modern lighting and energy transmission, is widely used in automotive lighting, display devices, medical instruments, and solar energy collection systems. Traditional light guide systems have long faced a persistent technical challenge: light energy loss and localized high-temperature thermal effects caused by light scattering at the light guide's tail end. This not only reduces the system's luminous efficiency but also forces the adoption of additional thermal management measures (such as radiators, heat pipes, or cooling systems), increasing system complexity and cost. Current technical solutions mainly involve adding a plane mirror or using special optical microstructures at the tail end, but these methods often focus on light recovery while neglecting thermal management, and may even exacerbate thermal problems due to concentrated light spots. For example, the patented "light guide with weakened bright-dark boundary" technology developed by Kebo Technology Co., Ltd. optimizes illumination uniformity through a wave-shaped design of the light-emitting surface, but it does not solve the problem of thermal effects at the tail end. Summary of the Invention

[0003] To address the shortcomings of the existing technology, the present invention aims to provide a tail-end reflection structure for automotive light guides.

[0004] The technical solution adopted in this utility model is as follows: A car light guide tail end reflection structure includes a light guide, a connector, and a spherical reflector. The spherical reflector includes a substrate, a metal coating layer, and a protective layer. The substrate is spherical in shape, with a metal coating layer fixed on its concave inner surface and a protective layer fixed on the outer layer of the metal coating layer. The spherical reflector is fixedly connected to the tail end of the light guide through the connector to form a functional port, which is located on the side of the connector between the light guide and the spherical reflector.

[0005] The light guide and connector are made of PMMA or PC material, and the spherical reflector is made of high-temperature resistant PC material.

[0006] The metal coating material is aluminum, and the protective layer material is silicon dioxide.

[0007] This utility model presents a novel automotive light guide tail-end reflection structure with a scientifically designed structure, ensuring safe and reliable operation. It achieves the dual functions of light energy recovery and thermal management. Compared to traditional planar reflector technology, the spherical reflector efficiently reflects stray light from the light guide end back into the light guide, significantly improving light utilization efficiency while reducing heat accumulation at the tail end, lowering local heat flux density, and thus reducing thermal management costs. The use of a spherical reflector structure with an optimized radius of curvature effectively improves luminous efficiency, reduces the peak temperature ΔT°C at the light guide end, and decreases the system's dependence on high-power light sources, thereby reducing overall system manufacturing and operating costs. Attached Figure Description

[0008] The accompanying drawings, which are included to provide a further understanding of the present invention and form part of this invention, illustrate exemplary embodiments and are used to explain the present invention, but do not constitute an undue limitation of the present invention. In the drawings: Figure 1 This is a schematic diagram of the automotive light guide tail end reflection structure of this utility model; Figure 2 for Figure 1 Schematic diagram of the AA section; In the diagram: 1-Light guide; 2-Connector; 3-Functional port; 4-Spherical mirror; 4a-Substrate; 4b-Metal coating layer; 4c-Protective layer; d-Working distance. Detailed Implementation

[0009] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described below are only used to explain this utility model. Key terms that need attention in these descriptions, including "functional port," "substrate," "reflector," and "working distance," are only for the purpose of facilitating a concise and clear description of this utility model and should not be construed as limiting the scope of this utility model.

[0010] like Figure 1-2As shown, the automotive light guide tail-end reflection structure of this utility model includes a light guide 1, a connector 2, and a spherical reflector 4. The light guide 1 is made of PMMA or PC material. The spherical reflector 4 includes a substrate 4a, a metal coating layer 4b, and a protective layer 4c. The substrate 4a is spherical in shape, and the metal coating layer 4b is fixedly coated on its concave inner surface. The protective layer 4c is fixedly coated on the outer layer of the metal coating layer 4b. The metal coating layer 4b is made of aluminum, and the protective layer 4c is made of silicon dioxide. The spherical reflector 4 is integrally connected to the tail end of the light guide 1 by injection molding through the connector 2, and a functional port 3 is provided on the side of the connector 2 between the light guide 1 and the spherical reflector 4.

[0011] The integration of the tail end of the light guide 1 with the spherical reflector 4 represents an interdisciplinary technological innovation, involving the integration and optimization of technologies from multiple fields such as optical design, thermodynamics, materials science, and manufacturing processes. In traditional light guides, light rays that cannot meet the conditions for total internal reflection (e.g., due to scattering, surface defects, or reaching the critical angle) continuously leak out from the light-emitting surface and the tail end. The tail end area of ​​the light guide 1 is very small, and the energy of all the light rays that eventually reach the tail end and are emitted is concentrated in this tiny area. Due to the small area, even if the total optical power is not high, the heat flux density here will be very high, forming a local high-temperature point, i.e., a "hot spot." This is similar to focusing sunlight with a magnifying glass, where the focal point temperature is extremely high. The main function of the spherical reflector 4 (operating near the focal point) is not only to reflect the light back, but more importantly, to "shape" the beam. It converts the divergent beam emitted from the small area at the tail end into a "collimated" or "small-angle divergent" beam with a larger cross-sectional area and reflects it back. This shaped light, after re-entering the light guide 1, will not immediately leak out entirely. Instead, it continues to propagate within the light guide 1 and gradually leaks out from the light-emitting surface over a longer region near the tail end. Previously, almost all the light energy was released at the tail end section; now, the light energy is released over a larger region extending forward from the tail end. The heat is no longer confined to a single point but is dispersed across a larger surface, increasing the contact area with air or heat dissipation structures by 3-4 times.

[0012] The core technology of this invention lies in its optical design and optimization. The design of the spherical reflector 4 requires multi-parameter collaborative optimization based on the optical guide size, material refractive index, and target application scenario. First, a complete ray tracing model was established. Based on a non-sequential optical simulation platform, the transmission of light within the optical guide 1, its reflection on the spherical mirror 4, and its return to the optical guide were simulated. Simulation results show that there exists an optimal radius of curvature range within which the best balance between light spot diffusion and reflection efficiency can be achieved. For a typical PMMA optical guide 1 with a diameter of 5mm, the optimal radius of curvature is approximately 2-3mm, at which point the luminous efficiency can be improved by up to 31%, while the light spot area is increased by 3-4 times, significantly reducing heat flux density. The working distance d between the spherical reflector 4 and the tail end of the optical guide 1 satisfies the following condition with respect to the radius of curvature R of the spherical reflector 4: 0.4R ≤ d ≤ 0.6R. By setting the working distance d to approximately equal to the focal length f of the spherical mirror, the spherical mirror 4 can reflect the light emitted from the tail end back to the light guide in a collimated or small-angle divergent manner. This improves light extraction efficiency while increasing the illumination area of ​​the returned beam on the light-emitting surface, reducing local heat flux density. A certain distance also exists between the two; some energy loss occurs as the light energy from the tail end passes through this space, reducing energy accumulation at the tail end of the light guide. Spherical reflection reduces heat flux density by increasing the heat source area. According to Fourier's law of heat conduction, a decrease in heat flux density q directly leads to a decrease in peak temperature, mathematically expressed as ΔT = q·R_th = P / A·R_th, where ΔT is the temperature rise, q is the heat flux density, R_th is the thermal resistance, P is the thermal power, and A is the heat source area. When the heat source area A increases, the heat flux density q decreases, resulting in a decrease in peak temperature ΔT.

[0013] Based on relevant technological research, the manufacturing method of the automotive light guide tail-end reflection structure of this utility model includes the following process steps: Step 1: Injection molding of optical guide 1 The light guide 1 is formed by injection molding using PMMA or PC material on an injection molding machine, and it usually adopts a 5mm diameter structure. Step 2: Injection molding of spherical mirror 4 High-temperature resistant PC material is used, and a precision injection molding machine is used for injection molding. In this embodiment, it is ensured that the spherical reflector 4 and the concave inner surface of its substrate 4a with a curvature radius of 3mm are accurately formed. Step 3: Coating the spherical mirror 4 A coating device was used to coat the inner concave surface of the front spherical mirror 4.

[0014] 1. 4b metal layer coating The spherical reflector 4 formed in the previous process is coated with a film on the inner concave surface of the substrate 4a of the spherical reflector 4 to form a mirror surface for reflection. Aluminum is chosen as the coating metal material because it is low in cost, has a mature process, good reflectivity in the ultraviolet to infrared region, good adhesion to the substrate, and is not prone to cracking or peeling. To ensure the formation of a continuous, pinhole-free, and dense film layer, a certain thickness is required. A thickness of 100nm-150nm can ensure yield and consistency, and also guarantee a reflectivity of more than 85% in the visible light range. In a high vacuum environment, high-purity aluminum wire or aluminum particles are heated to vaporization by resistance heating or electron beam bombardment. Aluminum atoms are ejected in a straight line and uniformly condense on the concave surface of the spherical reflector 4 at a lower temperature to form a thin film. Throughout the coating process, the temperature is strictly controlled below 100℃ using a water cooling system because the glass transition temperature of high-temperature resistant PC is 147℃. If the operating temperature approaches or exceeds this temperature, the material will begin to soften, deform, and even cause damage to the overall structure. Adjust the equipment to stabilize the evaporation rate at 0.5-2 nm / s, calculated based on the target thickness. For example, if the target thickness is 100 nm and the rate is 1 nm / s, the time would be 100 seconds. The coating time itself is not long, typically ranging from tens of seconds to a few minutes, and is mainly determined by the required film thickness and the power of the evaporation source.

[0015] 2. Protective layer 4C coating A protective layer 4c is deposited on the outside of the metal coating layer 4b of the spherical reflector 4. The protective layer 4c is made of silicon dioxide and has a thickness of 80nm-120nm. It protects the metal coating layer 4b during use.

[0016] Step 4: Injection molding of connector 2 Using PMMA or PC material, injection molding is performed on an injection molding machine to form connector 2, which has a height of 1.5mm; Step 5: Weld the light guide 1 and the spherical mirror 4 together. In this embodiment, ultrasonic welding equipment is used. A connector 2 with a height of 1.5mm is used to weld the light guide 1 and the spherical reflector 4 together via the connector 2. Both are made of high molecular polymers, which have good compatibility and can achieve high-strength, sealed welding. Furthermore, the working distance d is determined by the height of the connector 2, which is 1.5mm. The working distance d forms a functional opening 3, which facilitates heat dissipation of the light guide 1 during use.

[0017] The above description is merely one embodiment of this utility model. For those skilled in the art, various modifications and variations of this utility model are possible, which will not be elaborated upon here. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the scope of protection claimed by this utility model.

Claims

1. A tail-end reflection structure for an automotive light guide, comprising a light guide (1), a connector (2), and a spherical reflector (4), characterized in that, The spherical reflector (4) includes a substrate (4a), a metal coating layer (4b), and a protective layer (4c). The substrate (4a) is spherical and has a metal coating layer (4b) fixed on its concave inner surface. The outer layer of the metal coating layer (4b) is fixed with a protective layer (4c). The spherical reflector (4) is fixedly connected to the light guide (1) through a connector (2) to form a functional port (3), which is located on the side of the connector (2) between the light guide (1) and the spherical reflector (4).

2. The automotive light guide tail-end reflection structure according to claim 1, characterized in that, The light guide (1) and connector (2) are made of PMMA or PC material, and the spherical reflector (4) is made of high-temperature resistant PC material.

3. The automotive light guide tail-end reflection structure according to claim 1, characterized in that, The metal coating layer (4b) is made of aluminum, and the protective layer (4c) is made of silicon dioxide.

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