Backlight module and head-up display device

Abstract

The invention provides a backlight module and a head-up display device, and the backlight module comprises a lens group which is provided with a groove for accommodating a light source; the reflection assembly is arranged on the light emitting side of the lens group, the reflection assembly is provided with a first inner surface and a second outer surface which are back to back, the first inner surface is located at the bottom of the reflection assembly, is obliquely arranged relative to the reference plane of the reflection assembly and is used for guiding light rays from the lens group, and the second outer surface is used for guiding light rays from the lens group. The second outer surface is configured to emit the light guided by the first inner surface. The embodiment of the invention provides a backlight module and a head-up display device so as to save the arrangement space of the backlight module and improve the backlight brightness uniformity.

Description

Technical Field

[0001] This invention relates to the field of display technology, and more particularly to a backlight module and a head-up display device. Background Technology

[0002] As cars become more and more common, they are also becoming increasingly intelligent. In order to improve driving safety and allow drivers to focus more on the road, more and more vehicles are using head-up displays (HUDs) instead of dashboards to display driving information.

[0003] A lenticular lens grating is incorporated into a head-up display (HUD) to enable glasses-free 3D display. Glasses-free 3D display technology refers to a 3D display technology that allows users to view 3D images directly with the naked eye without wearing special 3D glasses, presenting a 3D effect. The lenticular lens grating performs a beam splitting function, allowing the left and right eyes to see different images, which are then merged in the brain to create a 3D effect.

[0004] The image source is the core component of the head-up display device, accounting for about 50% of the total cost of the head-up display device. The role of the image source is to generate the output image of the head-up display device. Since the overall efficiency of the head-up display device is not high, the brightness and efficiency of the backlight are required to be high. A good backlight design can significantly reduce the overall power consumption of the head-up display device, thereby reducing heat generation.

[0005] Because of the brightness and power consumption requirements of head-up display devices (HUDs), HUDs often adopt a directional backlight design, which results in a large overall size of the backlight module, making it difficult to arrange the HUD. Summary of the Invention

[0006] This invention provides a backlight module and a head-up display device to save space for the backlight module and improve the uniformity of backlight brightness.

[0007] In a first aspect, embodiments of the present invention provide a backlight module, comprising:

[0008] A lens assembly having a recess for accommodating a light source;

[0009] A reflective component is disposed on the light-emitting side of the lens group. The reflective component has a first inner surface and a second outer surface facing each other. The first inner surface is located at the bottom of the reflective component and is arranged at an angle relative to the reference plane of the reflective component to guide light from the lens group. The second outer surface is configured to emit light guided by the first inner surface.

[0010] Optionally, the first inner surface includes a reflective surface.

[0011] Optionally, the reflecting surface includes a prism array, which comprises reflecting prisms arranged in an array.

[0012] Optionally, the reflecting prism includes a prism reflecting surface and a prism connecting surface, wherein the prism connecting surface connects the prism reflecting surfaces of two adjacent reflecting prisms;

[0013] The angle between the prism's reflecting surface and the horizontal line is greater than or equal to 30° and less than or equal to 60°.

[0014] The lens group includes a light-incident surface adjacent to the groove, and the light-incident surface is rotationally symmetrical about the horizontal line.

[0015] Optionally, the angle between the reflective surface and the horizontal line is 45°.

[0016] Optionally, the reflecting surface includes a Fresnel lens surface.

[0017] Optionally, a reflective film is attached to the first inner surface.

[0018] Optionally, the reflective film includes a Fresnel lens reflective film.

[0019] Optionally, the reflective film includes a holographic reflective film.

[0020] Optionally, the first inner surface includes a first partition surface and a second partition surface, the first partition surface including a reflective surface, and the second partition surface having a reflective film attached.

[0021] Optionally, the second outer surface includes a curved surface that protrudes toward the first inner surface, or the second outer surface includes a Fresnel lens surface.

[0022] Optionally, the surface may include a freeform surface or an aspherical surface.

[0023] Optionally, the reflective assembly further has a third surface and a fourth surface facing away from each other, the fourth surface being located on the side of the reflective assembly away from the lens group;

[0024] The height of the third surface is greater than the height of the fourth surface.

[0025] Optionally, the lens group is a total internal reflection lens, used to reflect incident light rays through total internal reflection inside the total internal reflection lens before they are emitted.

[0026] In a second aspect, embodiments of the present invention provide a head-up display device, including an image source, the image source including the backlight module, liquid crystal display panel and lenticular lens grating described in the first aspect, the liquid crystal display panel being located between the backlight module and the lenticular lens grating.

[0027] In this embodiment of the invention, the first inner surface of the reflective component serves as a guiding surface (e.g., a reflective surface), and the second outer surface of the reflective component serves as a light-emitting surface. The collimated light projected from the side by the lens assembly is reflected by the reflective component and then emitted from the front of the backlight module via the second outer surface. The side-incident lighting method of the backlight module reduces its thickness, saving space for its arrangement and consequently saving space for the head-up display device. Furthermore, the reflective component can homogenize the light, improving the uniformity of backlight brightness. Attached Figure Description

[0028] Figure 1 A perspective view of a backlight module provided in an embodiment of the present invention;

[0029] Figure 2 A cross-sectional view of a backlight module provided in an embodiment of the present invention;

[0030] Figure 3 A cross-sectional view of a reflecting prism provided in an embodiment of the present invention;

[0031] Figure 4 A cross-sectional view of another backlight module provided in an embodiment of the present invention;

[0032] Figure 5 A cross-sectional view of another backlight module provided in an embodiment of the present invention;

[0033] Figure 6 A cross-sectional view of another backlight module provided in an embodiment of the present invention;

[0034] Figure 7 A cross-sectional view of another backlight module provided in an embodiment of the present invention;

[0035] Figure 8 A cross-sectional view of another backlight module provided in an embodiment of the present invention;

[0036] Figure 9 A perspective view of an image source provided in an embodiment of the present invention;

[0037] Figure 10 This is a schematic diagram of a head-up display device provided in an embodiment of the present invention. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0039] Figure 1A perspective view of a backlight module provided in an embodiment of the present invention; Figure 2 This is a cross-sectional view of a backlight module provided in an embodiment of the present invention; see reference. Figure 1 and Figure 2 The backlight module includes a lens assembly 100 and a reflective component 200. The lens assembly 100 has a recess 110 for accommodating a light source; the reflective component 200 is located on the side of the lens assembly 100 away from the recess 110, and is disposed on the light-emitting side of the lens assembly 100. The reflective component 200 has a first inner surface 210 and a second outer surface 220 facing each other. The reflective component 200 includes the opposing first inner surface 210 and the second outer surface 220, and the light source in the recess 110 (… Figure 1 and Figure 2 Light emitted from the lens group 100 (not shown) is reflected and projected onto the reflective assembly 200. A first inner surface 210 is located at the bottom of the reflective assembly 200 and is arranged at an angle relative to the reference plane of the reflective assembly 200. The first inner surface 210 is used to guide the light from the lens group 100. The first inner surface 210 is configured to guide the light from the lens group 100. A second outer surface 220 is configured to emit the light guided by the first inner surface 210. For example, the guiding effect of the first inner surface 210 on the light is such that the light is reflected at the location of the first inner surface 210.

[0040] In this embodiment of the invention, the first inner surface 210 of the reflective component 200 serves as a guiding surface (e.g., a reflective surface), and the second outer surface 220 of the reflective component 200 serves as a light-emitting surface. The collimated light projected from the side by the lens group 100 is reflected by the reflective component 200 and then emitted from the front of the backlight module via the second outer surface 220. The side-incident backlight module reduces its thickness, saving space for its arrangement and consequently saving space for the head-up display device. Furthermore, the reflective component 200 can homogenize the light, improving the uniformity of backlight brightness.

[0041] refer to Figure 1 and Figure 2 The first inner surface 210 includes a reflective surface 300. The reflective surface 300 is used to reflect light, so that light incident horizontally or nearly horizontally onto the reflective surface 300 is reflected and then projected vertically or nearly vertically onto the second outer surface 220.

[0042] refer to Figure 1 and Figure 2 The reflecting surface 300 includes a prism array, which includes reflective prisms 310 arranged in an array. The reflective prisms 310 are tiny structural units formed by the unevenness of the reflecting surface 300.

[0043] For example, the reflecting prism 310 is a triangular prism that extends along the X direction. Multiple reflecting prisms 310 are arranged in the YZ plane along a direction that gradually moves away from the lens group 100 and gradually moves closer to the second outer surface 220. The YZ plane is the plane determined by the Y and Z directions.

[0044] For example, multiple lens groups 100 are arranged in a row along the X direction to reduce the thickness of the backlight module. In other embodiments, the multiple lens groups 100 may be arranged in an array along both the X and Z directions.

[0045] Figure 3 A cross-sectional view of a reflecting prism provided in an embodiment of the present invention; see reference. Figures 1-3 The reflecting prism 310 includes a prism reflecting surface 311 and a prism connecting surface 312. The prism connecting surface 312 connects the prism reflecting surfaces 311 of two adjacent reflecting prisms 310; the prism reflecting surfaces 311 connect the prism connecting surfaces 312 of two adjacent reflecting prisms 310. The angle between the prism reflecting surface 311 and the reference plane M1 of the reflecting assembly 200 is α, where α is greater than or equal to 30° and less than or equal to 60°.

[0046] For example, the lens assembly 100 includes a light-incident surface 111 adjacent to a groove 110, and the light-incident surface 111 is rotationally symmetrical about the central axis L1 of the groove. The reference plane M1 of the reflective assembly 200 is parallel to the central axis L1 of the groove.

[0047] The reflecting surface 300 is a wrinkled surface, comprising a prism reflecting surface 311 and a prism connecting surface 312. The prism reflecting surface 311 has a light-reflecting function, thus enabling the reflecting surface 300 to reflect light. Total internal reflection occurs at the prism reflecting surface 311 of the reflecting prism 310 to improve the light reflection efficiency.

[0048] Optionally, α is 45°, so that light rays incident horizontally or nearly horizontally on the prism reflecting surface 311 are reflected and then projected vertically or nearly vertically onto the second outer surface 220.

[0049] Optionally, the reflective surface 300 includes a Fresnel lens surface (not shown). That is, at least a portion of the reflective surface 300 is a corrugated surface, and by fabricating at least a portion of the reflective surface 300 as a Fresnel lens surface, the reflection of light is achieved using the Fresnel lens surface. Setting at least a portion of the reflective surface 300 as a Fresnel lens surface can further reduce the thickness of the reflective component 200 and the thickness of the backlight module. In addition, the Fresnel lens surface can better control the exit angle of the reflected light, better modulate the light, and reflect the light at the required angle before it exits from the second outer surface 220.

[0050] Figure 4 A cross-sectional view of another backlight module provided in an embodiment of the present invention; see reference. Figure 4 A reflective film 400 is attached to the first inner surface 210. The reflective film 400 is used to reflect light, so that light incident horizontally or nearly horizontally onto the reflective film 400 is reflected and then projected vertically or nearly vertically onto the second outer surface 220.

[0051] For example, the first inner surface 210 includes a plane to facilitate the attachment of the reflective film 400 to the first inner surface 210. When the first inner surface 210 includes a plane or a wrinkled surface, the first inner surface 210 is inclined relative to the reference plane M1 of the reflective assembly 200, and the distance between the first inner surface 210 and the second outer surface 220 gradually decreases along a direction that gradually moves away from the lens group 100 and gradually moves closer to the second outer surface 220.

[0052] refer to Figure 4 The reflective film 400 includes a Fresnel lens reflective film 410. The Fresnel lens reflective film 410 includes a Fresnel lens surface. The Fresnel lens surface is used to reflect light. On one hand, the thickness of the reflective component 200 can be further reduced, thus reducing the thickness of the backlight module. On the other hand, the Fresnel lens reflective film 410 can better control the exit angle of the reflected light, better modulate the light, and reflect the light at the required angle before it exits from the second outer surface 220. The Fresnel lens surface is a reflective surface with curvature.

[0053] For example, the backlight module also includes a light source 511, which is located in the groove 110. The light emitted from the light source 511 is collimated by the lens group 100 and then projected onto the reflective component 200.

[0054] Figure 5 A cross-sectional view of another backlight module provided in an embodiment of the present invention; see reference. Figure 5 The reflective film 400 includes a holographic reflective film 420. The holographic reflective film 420 is used to reflect light. On one hand, this further reduces the thickness of the reflective component 200 and the backlight module. On the other hand, the holographic reflective film 420 can better control the exit angle of the reflected light, better modulate the light, and reflect the light at the required angle before it exits from the second outer surface 220. The Fresnel lens surface is a reflective surface with curvature.

[0055] Among them, the holographic reflective film 420 is a diffractive optical element made based on the principle of holography. It uses a photosensitive thin film as a substrate and controls the phase and amplitude of light waves by recording interference fringes. The main types include holographic lenses, holographic gratings, holographic filters, and holographic scanners. Compared with traditional optical elements, it has the advantages of being lightweight and capable of overlapping recording.

[0056] Figure 6A cross-sectional view of another backlight module provided in an embodiment of the present invention; see reference. Figure 6 The first inner surface 210 includes a first partition surface 201 and a second partition surface 202. The first partition surface 201 includes a reflective surface 300, and the second partition surface 202 is attached with a reflective film 400.

[0057] For example, refer to Figure 6 The first partition surface 201 includes a reflective surface 300, which includes a prism array, comprising reflective prisms 310 arranged in an array. In other embodiments, the reflective surface 300 within the first partition surface 201 includes a Fresnel lens surface. A reflective film 400 is attached to the second partition surface 202, and the reflective film 400 includes a holographic reflective film 420. In other embodiments, the holographic reflective film 420 within the second partition surface 202 includes a Fresnel lens reflective film 410.

[0058] In some embodiments, reflective surfaces 300 may be provided on both the first partition surface 201 and the second partition surface 202, and the reflective surfaces 300 on the two partition surfaces may respectively include a prism array and a Fresnel lens surface. Alternatively, reflective films 400 may be attached to both the first partition surface 201 and the second partition surface 202, and the reflective films 400 attached to the two partition surfaces may respectively include a Fresnel lens reflective film 410 and a holographic reflective film 420.

[0059] Optionally, refer to Figure 6 The second outer surface 220 includes a curved surface that protrudes toward the first inner surface 210, or the second outer surface 220 includes a Fresnel lens surface, and the second outer surface 220 sets the emitted light to be non-parallel. The optical path is designed to couple the head-up display device's imaging, matching the head-up display device's divergence angle and light emission direction.

[0060] For example, the second outer surface 220 includes a concave curved surface that is recessed toward the interior of the reflective component 200. When collimated or parallel light is projected onto the second outer surface 220, the emitted light, after being modulated by the second outer surface 220, exhibits a divergent state.

[0061] Furthermore, the curved surface of the second outer surface 220 includes a freeform surface or an aspherical surface. It should be noted that, as... Figure 4 and Figure 5 In the backlight module shown, because the thickness of the backlight module is small, the degree of concavity or convexity on the second outer surface 220 is small, in fact, as Figure 4 and Figure 5 The second outer surface 220 shown also includes a curved surface.

[0062] For example, refer to Figure 2 , Figure 4 and Figure 5The lens group 100 and the reflective component 200 are integrally formed. The lens group 100 and the reflective component 200 are different parts of the same element. In terms of manufacturing process, the lens group 100 and the reflective component 200 can be formed separately on the same element blank by etching.

[0063] Figure 7 A cross-sectional view of another backlight module provided in an embodiment of the present invention; see reference. Figure 7 The lens group 100 and the reflective component 200 are set independently, and are spaced apart, or fixed by adhesive or by contact fixation. Figure 7 The diagram illustrates the arrangement of the lens group 100 and the reflective component 200 with an air gap between them. A certain distance of air separates the lens group 100 and the reflective component 200.

[0064] Figure 8 A cross-sectional view of another backlight module provided in an embodiment of the present invention; see reference. Figure 8 The backlight module also includes a flat glass 500, which is located between the lens group 100 and the reflective component 200. The lens group 100 and the reflective component 200 are connected and fixed together through the flat glass 500.

[0065] Optionally, the reflective assembly 200 further has a third surface 230 and a fourth surface 240 facing away from each other. The third surface 230 is located on the side of the reflective assembly 200 adjacent to the lens group 100, and the fourth surface 240 is located on the side of the reflective assembly 200 away from the lens group 100. The third surface 230 is connected to the second outer surface 220, and the fourth surface 240 is connected to the first inner surface 210 and the second outer surface 220. The height of the third surface 230 is greater than the height of the fourth surface 240.

[0066] For example, the third surface 230, adjacent to the lens group 100, receives light from the lens group 100 and has a larger area and height. The first inner surface 210 is arranged at an angle relative to the reference plane of the reflective assembly 200, and the thickness of the reflective assembly 200 gradually decreases along the direction toward the fourth surface 240. The fourth surface 240 has a smaller area and height.

[0067] Optionally, the lens group 100 is a total internal reflection lens, used to reflect incident light rays after total internal reflection within the lens. The incident light rays in the lens group 100 can be light rays emitted by a light source.

[0068] Figure 9 A perspective view of an image source provided in an embodiment of the present invention; Figure 10 This is a schematic diagram of a head-up display device provided in an embodiment of the present invention. (Reference) Figure 9 and Figure 10 The head-up display device includes an image source 610, which includes the backlight module 510 described in the above embodiment. The image source 610 also includes a liquid crystal display panel 520 and a lenticular lens grating 530. The liquid crystal display panel 520 is located between the backlight module 510 and the lenticular lens grating 530. Outgoing light rays emitted through the second outer surface 220 provide backlight for the liquid crystal display panel 520. After passing through the liquid crystal display panel 520, left-eye image beams and right-eye image beams are generated. The lenticular lens grating 530 is located in the propagation path of the left-eye and right-eye image beams, and is used to split and project the left-eye and right-eye image beams.

[0069] For example, the head-up display device includes an image source 610, a first reflector 621, and a second reflector 622. The first reflector 621 can be a plane mirror or a curved mirror, and the second reflector 622 can be a curved mirror. The light beam emitted from the head-up display device is projected onto the windshield 630, reflected by the windshield 630, and enters the user's (e.g., driver's) eye box 640, forming a virtual image of the target in front of the user's eye box 640.

[0070] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. A backlight module, characterized in that, The application relates to a backlight module, comprising: a lens group having a recess accommodating a light source; a reflection assembly arranged on a light exit side of the lens group, the reflection assembly having a first inner surface and a second outer surface opposite to each other, wherein the first inner surface is located at the bottom of the reflection assembly and is arranged in an inclined manner relative to a reference plane of the reflection assembly for guiding light from the lens group, and the second outer surface is configured to exit light guided by the first inner surface.

2. The backlight module of claim 1, wherein, The first inner surface comprises a reflection surface.

3. The backlight module of claim 2, wherein, The reflection surface comprises a prism array, and the prism array comprises arrayed reflection prisms.

4. The backlight module of claim 3, wherein, The reflection prisms comprise prism reflection surfaces and prism connecting surfaces connecting the prism reflection surfaces of two adjacent reflection prisms. The prism reflection surface has an angle greater than or equal to 30 degrees and less than or equal to 60 degrees with the reference plane of the reflection assembly.

5. The backlight module of claim 1, wherein, The lens group comprises a light entrance surface adjacent to the recess, and the light entrance surface is symmetrical about a central axis of the recess.

6. The backlight module of claim 2, wherein, The reflection surface comprises a Fresnel lens surface.

7. The backlight module of claim 1, wherein, The first inner surface is attached with a reflection film.

8. The backlight module of claim 7, wherein, The reflection film comprises a Fresnel lens reflection film.

9. The backlight module according to claim 7, characterized in that, The reflection film comprises a holographic reflection film.

10. The backlight module of claim 1, 2 or 7, wherein, The first inner surface comprises a first sub-surface and a second sub-surface, the first sub-surface comprises a reflection surface, and the second sub-surface is attached with a reflection film.

11. The backlight module of claim 1, wherein, The second outer surface comprises a curved surface protruding towards the first inner surface, or the second outer surface comprises a Fresnel lens surface.

12. The backlight module of claim 11, wherein, The curved surface comprises a free-form surface or an aspheric surface.

13. The backlight module of claim 1, wherein, The reflection assembly further has a third surface and a fourth surface opposite to each other, and the fourth surface is located on the surface of the reflection assembly away from the lens group. The height of the third surface is greater than that of the fourth surface.

14. The backlight module of claim 1, wherein, The lens group is a total reflection lens for exiting light after total reflection inside the total reflection lens.

15. A head-up display device, characterized by comprising: The application further relates to an image source comprising the backlight module, a liquid crystal display panel and a cylindrical lens grating, and the liquid crystal display panel is located between the backlight module and the cylindrical lens grating.

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