Light guide structure and backlight module for head-up display system
By using a combination of solid light guides and diffusers in the head-up display system, the problems of large light loss, poor uniformity, and large field of view beam angle in the backlight module are solved, achieving high light utilization, good uniformity, and module miniaturization.
Patent Information
- Application Number
- CN202422609283.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-29
- Publication Date
- 2025-09-09
- Estimated Expiration
- 2034-10-29
AI Technical Summary
The backlight module of the existing head-up display system has large light beam loss, poor uniformity and a large field of view beam angle, resulting in a large module size.
Multiple solid light guides are used, including an incident surface, an exit surface and a total reflection surface. After being refracted by the incident surface, the light is totally reflected inside the solid light guide and emitted from the exit surface. The total reflection principle of the solid light guide is used to reduce the exiting beam angle, and the diffusion part is combined to improve the uniformity of the light. The light source part independently controls the brightness of the light.
The system achieves small light beam loss, good uniformity, stable chromaticity, narrow field of view beam angle, reduced module volume, reduced cost and improved light utilization.
Smart Images
Figure CN223320617U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of head-up display systems, in particular to a light guide structure and a backlight module for a head-up display system. Background Art
[0002] The head-up display (HUD) system is used to project driving status, navigation, assisted driving and other information directly onto the vehicle's windshield as a virtual image to convey information to the driver. The driver does not need to switch his line of sight and can understand the vehicle status and other information by keeping his eyes forward, which reduces blind driving time and improves driving safety.
[0003] The light-guiding structure of the backlight module of existing head-up display systems is generally a hollow cavity. Its reflective surface requires coating or painting (metal or dielectric reflective layer) to achieve full reflection. This results in poor light uniformity and is not conducive to reducing the field of view beam angle. To improve light uniformity and reduce the field of view beam angle, current light-guiding components increase the height or length of the reflective cavity to increase the optical path, but this results in a larger backlight module. Utility Model Content
[0004] The purpose of the present invention is to provide a light guide structure and a backlight module for a head-up display system to solve the problems existing in the above-mentioned prior art. The light beam of the backlight module has small light loss, good uniformity, more stable chromaticity, and can also reduce the field of view beam angle.
[0005] To achieve the above purpose, the present invention provides the following solutions:
[0006] The utility model provides a light-guiding structure, comprising a plurality of solid light-guiding members, wherein the solid light-guiding members comprise an incident surface, an exit surface and a total reflection surface, wherein the incident surface and the exit surface are arranged opposite to each other, the total reflection surface connects the incident surface and the exit surface, the area of the incident surface is smaller than the area of the exit surface, and after the light is refracted by the incident surface, it propagates through total reflection in the solid light-guiding member and is emitted from the exit surface.
[0007] Preferably, the solid light guide member is a conical solid light guide member.
[0008] Preferably, the tapered solid light guide member is conical or pyramidal.
[0009] Preferably, the exit surface is a free-form surface.
[0010] Preferably, the height of the solid light guide is 20 mm-45 mm.
[0011] Preferably, the ratio of the area of the incident surface to the area of the exit surface is 1:4-1:13.
[0012] The present utility model also provides a backlight module for a head-up display system, including the light guide structure, the bracket, the diffusion part and the light source part, the light guide structure, the diffusion part and the light source part are all fixedly mounted on the bracket, the solid light guide is located between the light source part and the diffusion part, and the light source part is close to the incident surface, and the diffusion part is close to the exit surface. After the light emitted by the light source part is refracted by the incident surface, it is totally reflected in the solid light guide and emitted from the exit surface. The diffusion part is used to receive the light emitted from the exit surface and diffuse the light to the light valve.
[0013] Preferably, the light source portion includes a plurality of light source components, and the plurality of light source components are arranged in a one-to-one correspondence with the plurality of solid light guide components.
[0014] Preferably, each of the light sources is an LED.
[0015] Preferably, all the light source components are arranged in a matrix manner, and each of the light source components can be independently controlled.
[0016] Compared with the prior art, the utility model has achieved the following technical effects:
[0017] The utility model provides a light guide element and a backlight module for a head-up display system. The light beam emitted by the light source part is refracted by the incident surface of the solid light guide part and then reflected multiple times by the total reflection surface of the solid light guide part before being emitted from the exit surface. The solid light guide part does not require coating, and the total reflection principle of the solid light guide part can reduce the exit beam angle and improve the light utilization rate of the backlight module. The incident surface area of the light guide part is smaller than the exit surface area, which can reduce the field of view beam angle; the light source part provides light for the backlight module and controls the brightness, and the diffusion part is used to homogenize the light emitted from the exit surface, thereby improving the distribution uniformity of the exit beam of the backlight module. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0019] Figure 1 A cross-sectional view of a backlight module for a head-up display system;
[0020] Figure 2 A side view of multiple solid light guides.
[0021] In the figure: 1-diffuser; 2-solid light guide; 3-light source; 4-bracket; 5-incident surface; 6-exit surface; 7-total reflection surface. DETAILED DESCRIPTION
[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0023] The purpose of the present invention is to provide a light guide structure and a backlight module for a head-up display system to solve the problems existing in the above-mentioned prior art. The light beam of the backlight module has small light loss, good uniformity, more stable chromaticity, and can also reduce the field of view beam angle.
[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific implementation methods.
[0025] Example 1
[0026] This embodiment provides a light guide structure, comprising a plurality of solid light guide members 2. The solid light guide members 2 include an incident surface 5, an exit surface 6, and a total reflection surface 7. The incident surface 5 and the exit surface 6 are arranged opposite each other. The total reflection surface 7 connects the incident surface 5 and the exit surface 6. The area of the incident surface 5 is smaller than that of the exit surface 6. After being refracted by the incident surface 5, the light is totally reflected and propagates within the solid light guide member 2 and is emitted from the exit surface 6. After being refracted by the incident surface 5 of the solid light guide member 2 and then reflected multiple times by the total reflection surface 7 of the solid light guide member 2, the light is emitted from the exit surface 6. The solid light guide member 2 does not require coating, and the total reflection principle of the solid light guide member 2 can reduce the exit beam angle, thereby improving the light utilization rate of the backlight module. The area of the incident surface 5 of the solid light guide member 2 is smaller than that of the exit surface 6, which can reduce the field of view beam angle.
[0027] In the embodiment of this embodiment, it is further preferred that the solid light guide 2 is a tapered solid light guide 2, the small end surface of the tapered solid light guide 2 is the incident surface 5, the tapered solid light guide 2 is conical or pyramidal, the large end surface of the tapered solid light guide 2 is the exit surface 6, and the side surface of the tapered solid light guide 2 is a total reflection surface 7. The geometric shape of the incident surface 5 is not limited and can be rectangular, square, circular, etc.
[0028] It is further preferred in the implementation manner of this embodiment that Figure 2As shown, the exit surface 6 is a free-form surface that rises toward the diffuser 1. This further reduces the field of view angle while reducing the height of the solid light guide 2. After the light beam is shaped by the free-form surface of the exit surface 6 and then diffused by the diffuser 1, it has better beam uniformity and more stable color. The height of the solid light guide 2 is 20mm-45mm, preferably 26mm-39mm, which can reduce the optical path, reduce the size of the backlight module, reduce costs, and adapt to more application scenarios.
[0029] In this embodiment, it is further preferred that the ratio of the area of the incident surface 5 to the area of the exit surface 6 is 1:4-1:13, preferably 1:9-1:11. The HUD is an optical system with a small field of view and requires matching a small exit beam angle. The ratio of the area of the incident surface 5 to the area of the exit surface 6 depends on the field of view of the HUD.
[0030] Example 2
[0031] This embodiment provides a backlight module for a head-up display system, such as Figure 1 As shown, it includes the light guiding structure, bracket 4, diffusion part 1 and light source part of embodiment 1, the light guiding structure, diffusion part 1 and light source part are all fixedly mounted on the bracket 4, the solid light guiding member 2 is located between the light source part and the diffusion part 1, and the diffusion part 1, the solid light guiding member 2 and the light source part are spaced a certain distance apart from each other, the light source part is close to the incident surface 5, the diffusion part 1 is close to the exit surface 6, the area of the incident surface 5 is smaller than the area of the exit surface 6, the light emitted by the light source part is refracted by the incident surface 5, is totally reflected in the solid light guiding member 2 and is emitted from the exit surface 6, the diffusion part 1 is used to receive the light emitted from the exit surface 6 and diffuse the light to the light valve (not shown in the figure). The light source part provides illumination for the backlight module and controls the brightness. The light beam emitted by the light source part is refracted by the incident surface 5 of the solid light guide 2 and then reflected multiple times by the total reflection surface 7 of the solid light guide 2 before being emitted from the exit surface 6. The solid light guide 2 does not require coating, and the total reflection principle of the solid light guide 2 can be used to reduce the exit beam angle and improve the light utilization rate of the backlight module. The area of the incident surface 5 of the solid light guide 2 is smaller than the area of the exit surface 6, which can reduce the field of view beam angle. The diffusion part 1 is used to homogenize the light emitted from the exit surface 6 and improve the distribution uniformity of the exit light beam of the backlight module.
[0032] It is further preferred in the implementation manner of this embodiment that the light source portion includes a plurality of light source elements 3 , and the plurality of light source elements 3 are arranged in a one-to-one correspondence with the plurality of solid light guide elements 2 .
[0033] It is further preferred in the implementation of this embodiment that the light source adopts LED. Under the same optical performance requirements, the power of a single LED used is lower and the number of LEDs is smaller. Compared with the existing technology, it can not only ensure the optical performance of the module, but also save energy efficiency and reduce costs.
[0034] In the implementation of this embodiment, it is further preferred that all light source elements 3 are arranged in a matrix manner, and each light source element 3 can be independently controlled. This backlight module is a direct-lit backlight, and the outgoing light beam enters the light valve vertically. The light source unit and the physical light guide 2 are both arranged in a matrix, such as 2*2, 2*5, 2*7, 3*3, 3*5, 3*7, etc. The specific arrangement is determined by the size of the light valve. Local light control can be achieved by controlling the power on and off of each light source unit, that is, independent brightness and darkness control is performed for different areas on the screen to meet local brightness and darkness requirements.
[0035] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only intended to help understand the method and core concept of the present invention. At the same time, those skilled in the art will find that the specific implementation methods and application scopes may vary based on the concept of the present invention. In summary, the contents of this specification should not be construed as limiting the present invention.
Claims
1. A light guide structure, characterized in that: The invention comprises a plurality of solid light guide members, wherein the solid light guide members include an incident surface, an exit surface and a total reflection surface. The incident surface and the exit surface are arranged opposite to each other, and the total reflection surface connects the incident surface and the exit surface. The area of the incident surface is smaller than the area of the exit surface. After the light is refracted by the incident surface, it propagates by total reflection in the solid light guide member and is emitted from the exit surface.
2. The light guide structure according to claim 1, wherein: The solid light guide member is a tapered solid light guide member.
3. The light guide structure according to claim 2, wherein: The tapered solid light guide member is in the shape of a cone or a pyramid.
4. The light guide structure according to claim 1, wherein: The exit surface is a free-form surface.
5. The light guide structure according to claim 1, wherein: The height of the solid light guide member is 20 mm to 45 mm.
6. The light guide structure according to claim 1, wherein: The ratio of the area of the incident surface to the area of the exit surface is 1:4-1:
13.
7. A backlight module for a head-up display system, characterized in that: The light guide structure comprises a light guide structure, a bracket, a diffusion part and a light source part according to any one of claims 1 to 6, wherein the light guide structure, the diffusion part and the light source part are all fixedly mounted on the bracket, the solid light guide part is located between the light source part and the diffusion part, and the light source part is close to the incident surface, and the diffusion part is close to the exit surface. After the light source part is refracted by the incident surface, the light is totally reflected in the solid light guide part and is emitted from the exit surface. The diffusion part is used to receive the light emitted from the exit surface and diffuse the light to the light valve.
8. The backlight module for a head-up display system according to claim 7, wherein: The light source portion includes a plurality of light source components, and the plurality of light source components are arranged in a one-to-one correspondence with the plurality of solid light guide components.
9. The backlight module for a head-up display system according to claim 8, characterized in that: Each of the light sources is an LED.
10. The backlight module for a head-up display system according to claim 9, characterized in that: All the light source components are arranged in a matrix manner, and each of the light source components can be independently controlled.