Device for improving HUD backlight illumination uniformity

Abstract

The utility model relates to a device for improving HUD backlight illumination uniformity, which comprises a first lens assembly, a second lens assembly, a diffusion sheet, an illumination plate and a dimming assembly, the diffusion sheet is arranged between the illumination plate and the second lens assembly, the first lens assembly is arranged on one side of the second lens assembly, and the second lens assembly is arranged on the other side of the second lens assembly. The dimming assembly is arranged between the first lens assembly and the second lens assembly, and the dimming assembly translates or rotates relative to the second lens assembly. A light adjusting assembly is arranged between a converging lens and an array integrated collimating lens, adjustable diaphragms are arranged between every two groups of LEDs in the transverse direction and the longitudinal direction, and light intensity distribution at the splicing position of two adjacent groups of light beams on an illumination surface is adjusted by changing the states of the diaphragms and controlling outgoing of large-angle light rays of the LEDs. Grid stripes with the brightness higher than that of the peripheral area at the splicing position are eliminated, and illumination uniformity is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of head-up displays, and in particular to a device for improving the uniformity of HUD backlight illumination. Background Art

[0002] A head-up display (HUD) on a car's windshield displays information directly on the car's windshield, eliminating the need for the driver to lower their head to see instrument information and ensuring safer driving. Head-up displays were first used on military aircraft. With technological advancements, their application in the automotive field is becoming increasingly widespread. HUD image production units can utilize a variety of technologies, such as TFT modules, DLP projection, LCOS projection, and LBS projection. TFT modules are simple in composition and compact in size, and are currently the most widely used. The backlighting of TFT modules often consists of multiple LEDs arranged in a dispersed manner, or multiple LEDs arranged in a dense arrangement. Distributed LED arrangements aid in heat dissipation, preventing excessive heat generation from the LEDs, which can affect light efficiency and reduce LED life and reliability.

[0003] Common lighting solutions include: LED light board + collimating lens assembly, LED light board + special lens + Fresnel mirror, LED light board + light bucket, and LED light board + reflector cup + microlens array + focusing lens. The LED light board + light bucket solution is simple to design, has low proofing costs, and is easy to implement as a platform. However, the uniformity of the lighting is significantly affected by the size of the light bucket. To achieve good uniformity, the light bucket length must be increased, which increases the size of the backlight unit and, consequently, the entire HUD system. This poses certain limitations in the increasingly compact vehicle space. The LED light board + collimating lens solution offers advantages such as small size, low cost, and simple assembly, but the biggest problem encountered is that the joints in the array assembly affect the uniformity of the lighting.

[0004] Existing HUD backlight devices often use a reflective design, such as that in CN205424587U. This design concentrates the LED chips, which can easily lead to excessive power density per unit area, hindering heat dissipation and affecting the LED's light efficiency. Furthermore, to achieve uniform illumination, a light pipe or light hopper is required to perform multiple internal reflections of light. The greater the number of reflections, the more uniform the output light. However, due to the large aperture, multiple reflections significantly increase the length of the light pipe, resulting in an excessively large volume that does not meet the overall HUD size design requirements.

[0005] To shorten the length of the lighting module while achieving highly uniform lighting output, existing technologies employ a collimated arrangement of multiple dispersed LED light sources. For example, CN111025642A employs a 2×3 array of LED chips and a lens array for primary focusing, followed by collimation through a Fresnel lens. This approach requires a larger focal length for the Fresnel lens to illuminate a large surface, such as a 4.1-inch or 5.1-inch TFT, increasing the system's footprint. Furthermore, the illumination at the four corners is insufficient, resulting in poor uniformity. Summary of the Invention

[0006] The utility model provides a device for improving the uniformity of HUD backlight illumination, aiming to solve the problem of poor uniformity of existing HUD backlight illumination.

[0007] The utility model provides a device for improving the uniformity of HUD backlight illumination, comprising a first lens assembly, a second lens assembly, a diffuser, a lighting plate and a dimming assembly, wherein the diffuser is arranged between the lighting plate and the second lens assembly, the first lens assembly is arranged on one side of the second lens assembly, the dimming assembly is arranged between the first lens assembly and the second lens assembly, and the dimming assembly translates or rotates relative to the second lens assembly.

[0008] As a further improvement of the present invention, the first lens assembly includes a plurality of first collimating lenses arranged in a transverse array, adjacent first collimating lenses are arranged at intervals, and the plurality of first collimating lenses form a first collecting plane.

[0009] As a further improvement of the present invention, the second lens assembly includes a plurality of second collimating lenses arranged in a longitudinal array, adjacent second collimating lenses are connected to each other, and the plurality of second collimating lenses form a second collecting plane.

[0010] As a further improvement of the present invention, after being emitted, the light source passes through the first collecting plane, the dimming component, the second collecting plane and the diffusion sheet in sequence and is presented on the lighting panel.

[0011] As a further improvement of the present invention, the dimming component includes several transverse diaphragms and several longitudinal diaphragms, the transverse diaphragms and the longitudinal diaphragms are arranged crosswise, one transverse diaphragm is arranged between two of the first collimating lenses, and one longitudinal diaphragm is arranged between the two first collimating lenses.

[0012] As a further improvement of the present invention, the transverse aperture moves along a plane parallel to or perpendicular to the diffuser, and the transverse aperture rotates around an axis horizontal to the second collecting plane.

[0013] As a further improvement of the present invention, the longitudinal diaphragm moves along a plane parallel to or perpendicular to the diffuser, and the longitudinal diaphragm rotates around an axis perpendicular to the second collecting plane.

[0014] As a further improvement of the present invention, the number of the transverse apertures is one less than the number of the first collimating lenses, and the number of the longitudinal apertures is one less than the number of the second collimating lenses.

[0015] As a further improvement of the present invention, the rotation angle range of the transverse aperture is 0-30 degrees, and the rotation angle range of the longitudinal aperture is 0-30 degrees.

[0016] As a further improvement of the present invention, the transmittance range of the dimming component is 1%-95%.

[0017] The beneficial effects of the present invention are as follows: a dimming component is provided between the converging lens and the array-integrated collimating lens, and an adjustable aperture is provided between each two groups of LEDs in the horizontal and vertical directions. By changing the state of the aperture, the emission of large-angle light from the LED is controlled, thereby adjusting the light intensity distribution at the splicing position of two adjacent groups of light beams on the lighting surface, eliminating the grid stripes at the splicing position where the brightness is higher than that of the surrounding area, and improving the uniformity of lighting. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is an overall diagram of the utility model;

[0019] Figure 2 The transverse aperture in the side view of the present invention is placed horizontally;

[0020] Figure 3 The horizontal aperture in the side view of the present invention is rotated and placed;

[0021] Figure 4 The longitudinal aperture is placed horizontally in the top view of the present invention;

[0022] Figure 5 The vertical aperture in the top view of the present invention is rotated and placed;

[0023] Figure 6 It is a schematic diagram of the lighting area of ​​the lighting board of the present invention.

[0024] Reference numerals: 1 - illumination plate, 2 - diffusion plate, 3 - first collimating lens, 4 - second collimating lens, 5 - transverse aperture, 6 - longitudinal aperture. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the terms "front," "rear," "left," "right," "upper," and "lower" used in the following description refer to directions in the accompanying drawings, and the terms "bottom," "top," "inner," and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0026] The utility model provides a device for improving the uniformity of HUD backlight illumination, comprising a first lens assembly, a second lens assembly, a diffuser 2, a lighting board 1 and a dimming assembly, wherein the diffuser 2 is arranged between the lighting board 1 and the second lens assembly, the first lens assembly is arranged on one side of the second lens assembly, the dimming assembly is arranged between the first lens assembly and the second lens assembly, and the dimming assembly translates or rotates relative to the second lens assembly.

[0027] As an embodiment of the present invention, the first lens assembly includes a plurality of first collimating lenses 3 arranged in a transverse array, adjacent first collimating lenses 3 are arranged at intervals, and the plurality of first collimating lenses 3 form a first collecting plane.

[0028] As another embodiment of the present invention, the second lens assembly includes a plurality of second collimating lenses 4 arranged in a longitudinal array, adjacent second collimating lenses 4 are connected to each other, and the plurality of second collimating lenses 4 form a second collecting plane.

[0029] As another embodiment of the present invention, after being emitted, the light source passes through the first collecting plane, the dimming component, the second collecting plane and the diffusion sheet 2 in sequence, and then appears on the lighting board 1.

[0030] As another embodiment of the present utility model, the dimming component includes a plurality of transverse diaphragms 5 and a plurality of longitudinal diaphragms 6, the transverse diaphragms 5 and the longitudinal diaphragms 6 are arranged crosswise, one transverse diaphragm 5 is arranged between two of the first collimating lenses 3, and one longitudinal diaphragm 6 is arranged between the two first collimating lenses 3.

[0031] As another embodiment of the present invention, the transverse aperture 5 moves along a plane parallel to or perpendicular to the diffuser 2 , and the transverse aperture 5 rotates around an axis horizontal to the second collecting plane.

[0032] As another embodiment of the present invention, the longitudinal diaphragm 6 moves along a plane parallel to or perpendicular to the diffuser 2 , and the longitudinal diaphragm 6 rotates around an axis perpendicular to the second collecting plane.

[0033] As another embodiment of the present invention, the number of the transverse apertures 5 is one less than the number of the first collimating lenses 3 , and the number of the longitudinal apertures 6 is one less than the number of the second collimating lenses 4 .

[0034] As another embodiment of the present invention, the rotation angle range of the transverse aperture 5 is 0-30 degrees, and the rotation angle range of the longitudinal aperture 6 is 0-30 degrees.

[0035] As another embodiment of the present invention, the transmittance of the dimming component ranges from 1% to 95%.

[0036] This utility model provides a device for improving the uniformity of HUD backlight illumination. The light source is typically a COB-packaged LED chip with a maximum illumination angle greater than 70°. The wide-angle diffused light emitted by the LED is focused and collected by a first collimating lens 3. Each LED corresponds to a first collimating lens 3, which typically has a circular aperture. The light focused by the first collimating lens 3 is further collimated by a second collimating lens 4. Each first collimating lens 3 is followed by a second collimating lens 4, and the array of second collimating lenses 4 is seamlessly connected. The second collimating lenses 4 typically have a rectangular aperture. The light emitted by the array of second collimating lenses 4 is collimated and incident on the diffuser 2. The surface of the diffuser 2 has microstructures that diffuse the incident collimated light at specific angles. The diffuser 2 typically has different diffusion angles in the horizontal and vertical directions, for example, 30° x 10°. The diffused light ultimately evenly illuminates the target area of ​​the illumination panel 1, such as the inner surface of a TFT. The illumination panel 1 typically forms a specific angle with the diffuser 2 to achieve the desired chief ray angle.

[0037] In the embodiment of the present invention, the first lens assembly and the second lens assembly are a 3×6 light source and collimating lens array, which can also be used in other numbers, such as 2×4, 3×5 or other arrangements. The number of the first collimating lenses 3 is m, and the number of the second collimating lenses 4 is n. Then the number of the transverse apertures 5 is m-1, and the number of the longitudinal apertures 6 is n-1. The transverse aperture 5 can be placed parallel to the second lens assembly, such as Figure 3 As shown, it can also be placed at a certain angle with the second lens assembly, such as Figure 4 The longitudinal aperture 6 can be placed parallel to the second lens assembly, as shown Figure 5 As shown, it can also be placed at a certain angle with the second lens assembly, such as Figure 6 The rotation angle of the transverse aperture 5 and the longitudinal aperture 6 is ±30 degrees.

[0038] The dimming principle of this device is as follows: since the second collimating lens 4 arrays are connected to each other, the large-angle light emitted by adjacent LEDs passes through the array of the second lens assembly, such as Figure 6 As shown, overlapping will occur in areas A and B of the lighting panel 1, resulting in uneven light intensity on the illuminated surface. By adding the transverse aperture 5 between the first and second lens assemblies, the transmittance ratio of light at large angles before the second lens assembly array is adjusted, thereby adjusting the light intensity in areas A and B of the lighting panel 1 and making the light distribution more uniform. Similar to the transverse aperture 5, the longitudinal aperture 6 is introduced to adjust the transmittance ratio of light at large angles before the second lens assembly array, thereby adjusting the light intensity of the grid on the illuminated surface.

[0039] The transverse aperture 5 and the longitudinal aperture 6 can both be translated in the z-axis direction of the device, the transverse aperture 5 can rotate around the x-axis of the device, and the longitudinal aperture 6 can rotate around the y-axis of the device. The transverse aperture 5 and the longitudinal aperture 6 can be made of metal or plastic baffles, die-cut Mylar baffles, large-angle microstructure diffusion films, prismatic microstructure films or other film materials. The transmittance of the dimming component can be from 1% to 95%. The function of the dimming component is to reduce Figure 6 The energy of the medium-brightness area B is too high, which reduces the difference in light intensity distribution between area A and area B, making the light intensity distribution of the entire lighting surface more uniform, thereby improving the uniformity of lighting.

[0040] The LED light board uses multiple LED chips arranged in a dispersed manner, independently collecting and converging light for each LED, then collimating the array as a whole, and finally combining the light beams to output a uniform lighting surface. Fully utilize the characteristics of LED chips such as good dispersed heat dissipation and compact structure. The dimming component is provided between the first lens assembly and the second lens assembly, and an adjustable aperture is provided between each two groups of LEDs in the horizontal and vertical directions. The aperture can be translated or rotated, and by changing the state of the aperture, the emission of large-angle light from the LED is controlled, thereby adjusting the light intensity distribution at the splicing position of the two adjacent groups of light beams on the lighting surface, eliminating the grid stripes at the splicing position where the brightness is higher than the surrounding area, and improving the uniformity of lighting. The transmittance of the aperture is selectable, and by changing the transmittance of the aperture, the emission light distribution of large-angle light from the LED is controlled, thereby adjusting the light intensity distribution at the splicing position of the two adjacent groups of light beams on the lighting surface, eliminating the grid stripes at the splicing position where the brightness is higher than the surrounding area, and improving the uniformity of lighting.

[0041] The above content is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention cannot be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. A device for improving the uniformity of HUD backlight illumination, characterized in that: The optical microscope comprises a first lens assembly, a second lens assembly, a diffuser, a lighting plate and a dimming assembly, wherein the diffuser is arranged between the lighting plate and the second lens assembly, the first lens assembly is arranged on one side of the second lens assembly, the dimming assembly is arranged between the first lens assembly and the second lens assembly, and the dimming assembly translates or rotates relative to the second lens assembly.

2. The device for improving HUD backlight uniformity according to claim 1, wherein: The first lens assembly includes a plurality of first collimating lenses arranged in a transverse array, adjacent first collimating lenses are arranged at intervals, and the plurality of first collimating lenses form a first collecting plane.

3. The device for improving HUD backlight uniformity according to claim 2, wherein: The second lens assembly includes a plurality of second collimating lenses arranged in a longitudinal array. Adjacent second collimating lenses are connected to each other, and the plurality of second collimating lenses form a second collecting plane.

4. The device for improving HUD backlight uniformity according to claim 3, wherein: After being emitted, the light source passes through the first collecting plane, the dimming component, the second collecting plane and the diffusion sheet in sequence, and then appears on the lighting panel.

5. The device for improving HUD backlight uniformity according to claim 3, wherein: The dimming component includes a plurality of transverse diaphragms and a plurality of longitudinal diaphragms, the transverse diaphragms and the longitudinal diaphragms are arranged crosswise, one transverse diaphragm is arranged between two of the first collimating lenses, and one longitudinal diaphragm is arranged between two of the first collimating lenses.

6. The device for improving HUD backlight uniformity according to claim 5, characterized in that: The transverse aperture moves along a plane parallel to or perpendicular to the diffuser, and the transverse aperture rotates around an axis horizontal to the second collecting plane.

7. The device for improving HUD backlight uniformity according to claim 5, wherein: The longitudinal aperture moves along a plane parallel to or perpendicular to the diffuser, and the longitudinal aperture rotates around an axis perpendicular to the second collecting plane.

8. The device for improving HUD backlight uniformity according to claim 5, wherein: The number of the transverse apertures is one less than the number of the first collimating lenses, and the number of the longitudinal apertures is one less than the number of the second collimating lenses.

9. The device for improving HUD backlight uniformity according to claim 5, wherein: The rotation angle range of the transverse aperture is 0-30 degrees, and the rotation angle range of the longitudinal aperture is 0-30 degrees.

10. The device for improving HUD backlight uniformity according to claim 5, wherein: The transmittance of the dimming component ranges from 1% to 95%.

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