HUD backlight module

Abstract

The utility model discloses an HUD backlight module. The HUD backlight module comprises an LED chip, a free-form surface lens, a Fresnel lens, a diffusion film and a TFT display chip which are sequentially arranged from front to back. After light emitted by the LED chip is received by the free-form surface lens, a light beam is subjected to secondary collimation by the Fresnel lens and then passes through the diffusion film to reach the TFT display chip. Compared with the prior art, the free-form surface lens scheme is adopted, the size advantage is obvious, due to the fact that the number of surface type variables is large, more free surface type changes are achieved, the surface type can be adjusted according to requirements to meet the optical performance requirement, and therefore the purposes of improving uniformity and reducing the size are achieved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of vehicle-mounted HUD, especially relates to a HUD backlight module. BACKGROUND

[0002] HUD is parallel display system, its effect is to project the important driving information such as speed and navigation to the windshield glass in front of driver, lets driver reach not to lower head, not to turn head just can see the important driving information such as speed and navigation, because the information of HUD needs to provide windshield glass reflection into the eye, but to ensure driving safety, the transmittance of windshield glass is very high, so as to ensure the brightness of virtual image, the light source of HUD needs to provide great brightness, usually needs to use high-power light source to improve the brightness of HUD, in the prior art, the light is concentrated by setting the conical reflector and the fresnel lens on the lamp bead, the characteristics of this scheme are low cost and simple structure, but also have the shortcomings of large size and poor uniformity, as the volume reserved for HUD in the car is limited, this requires that the backlight module must meet the characteristics of small size, so it is urgent to solve the problem of reducing the size of HUD while ensuring the optical performance.

[0003] Specifically, as shown in Figure 1 The prior art is composed of LED chip 1, reflector lens group 2, fresnel lens 3, diffusion film 4 and TFT display chip 5, in the scheme, the light beam emitted by LED chip 1 reaches fresnel lens 3 after being reflected by reflector lens group 2 multiple times, and fresnel lens 3 further collimates the light beam to obtain a light beam with a smaller angle, and the collimated light beam reaches TFT display chip 5 after passing through diffusion film 4. The scheme has simple structure, but the length of reflector lens group 2 directly affects the spot uniformity on the surface of TFT display chip 5.

[0004] In order to ensure the spot uniformity and the angle of collimated light beam, the length of reflector lens group 2 must not be too small in the prior art, but this leads to a large size of the backlight module, which cannot meet the requirement of small size, for example, if the size is reduced, that is, the length of the reflector group is shortened, the spot uniformity will be reduced. Figure 1 And Figure 2 As shown in the drawings, the distance between LED chip 1 and fresnel lens 3 is 32mm. CONTENT OF THE UTILITY MODEL

[0005] The main purpose of the utility model is to provide a HUD backlight module, which aims to reduce the size of the HUD while ensuring the optical performance of the HUD backlight module.

[0006] To achieve the above purpose, the utility model provides a HUD backlight module, which comprises LED chip, free-form surface lens, fresnel lens, diffusion film and TFT display chip arranged in sequence from front to back.

[0007] The light emitted by the LED chip passes through the free-form surface lens for light collection and processing, and then passes through the Fresnel lens for secondary collimation and then passes through the diffusion film to the TFT display chip.

[0008] The further technical solution of the utility model is that the thickness of the free-form surface lens is 10mm, the length is 27mm, and the width is 19mm.

[0009] The further technical solution of the utility model is that the material of the free-form surface lens is PC.

[0010] The further technical solution of the utility model is that the radius R of the first curved surface of the free-form surface lens is -50mm.

[0011] The further technical solution of the utility model is that the face type XY polynomial of the second curved surface of the free-form surface lens is:

[0012] r=21.127 k=-0.55274

[0013] X2=0.036658 Y2=-0.030543

[0014] X4=3.4259E-004 Y4=2.1121E-004;

[0015] The face type expression is: .

[0016] The further technical solution of the utility model is that the distance between the LED chip and the Fresnel lens is 27mm.

[0017] The utility model HUD back light module has the beneficial effect that:

[0018] Compared with the prior art, the utility model adopts the free-form surface lens scheme, and has obvious volume advantage, because the face type has many variables, has more free face type change, can adjust the face type according to the requirement and match the optical performance requirement, thereby achieving the purpose of improving uniformity and reducing volume. DRAWINGS

[0019] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced as follows, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other drawings can also be obtained according to the structure shown in these drawings without creative labor.

[0020] Figure 1 It is the structure schematic view of the HUD back light module in the prior art.

[0021] Figure 2 is the spot uniformity diagram of the HUD module in the prior art;

[0022] Figure 3 is the light path structure diagram of the preferred embodiment of the HUD backlight module of the utility model;

[0023] Figure 4 is the light plate uniformity diagram of the HUD backlight module of the utility model.

[0024] The implementation, functional features and advantages of the utility model will be further described with reference to the drawings in combination with embodiments. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the utility model will be clearly and completely described in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the utility model.

[0026] Please refer to Figure 3 and Figure 4 The utility model provides a kind of HUD backlight module, the preferred embodiment of the utility model of HUD backlight module includes LED chip, free curved surface lens, Fresnel lens, diffusion film and TFT display chip arranged in order from front to back.

[0027] The light emitted by the LED chip is received and processed by the free curved surface lens, and then the light beam passes through the Fresnel lens for secondary collimation and reaches the TFT display chip through the diffusion film.

[0028] The embodiment can ensure the uniformity of the spot on the surface of the TFT display chip and also ensure that the collimation angle of the light beam is small, which is more conducive to improving the backlight brightness.

[0029] In the embodiment, the thickness of the free curved surface lens is 10mm, the length is 27mm, and the width is 19mm.

[0030] In the embodiment, the material of the free curved surface lens is PC.

[0031] In the embodiment, the radius R of the curved surface 1 of the free curved surface lens is -50mm, where R refers to the radius of the spherical surface.

[0032] In the embodiment, the face type XY polynomial of the curved surface 2 of the free curved surface lens is:

[0033] r = 21.127 k = -0.55274

[0034] X2 = 0.036658 Y2 = -0.030543

[0035] X4 = 3.4259E-004 Y4 = 2.1121E-004.

[0036] Data into the formula, namely the surface type surface.

[0037] The surface expression is: .

[0038] In the embodiment, the distance between the LED chip and the Fresnel lens is 27mm. By using the embodiment, the light plate uniformity can reach 80%.

[0039] The HUD backlight module has the following beneficial effects:

[0040] Compared with the prior art, the free-form surface lens scheme has obvious volume advantage, has more free surface changes due to the multiple surface variables, can adjust the surface to match the optical performance requirements according to the requirements, thereby improving the uniformity and reducing the volume.

[0041] The above is only the preferred embodiment of the utility model, and does not limit the patent range of the utility model, and any equivalent structural transformation, direct / indirect application in other related technical fields by using the utility model specification and the attached drawings under the concept of the utility model are included in the patent protection range of the utility model.

Claims

1. A HUD backlight module, characterized in that, Comprise: LED chip, free-form surface lens, Fresnel lens, diffusion film and TFT display chip are arranged in sequence from front to back; The light emitted by the LED chip is collected by the free-form surface lens, and then the light beam is collimated by the Fresnel lens again, and then passes through the diffusion film to reach the TFT display chip.

2. The HUD backlight module of claim 1, wherein, The thickness of the free-form surface lens is 10 mm, the length is 27 mm, and the width is 19 mm.

3. The HUD backlight module of claim 2, wherein, The material of the free-form surface lens is PC.

4. The HUD backlight module of claim 3, wherein, The radius R of the first curved surface of the free-form surface lens is -50 mm, wherein R refers to the radius of the spherical surface.

5. The HUD backlight module of claim 4, wherein, The face type XY polynomial of the second curved surface of the free-form surface lens is: r＝21.127k＝-0.55274 X2=0.036658 Y2=-0.030543 X4=3.4259E-004 Y4=2.1121E-004; wherein the surface expression is:

6. The HUD backlight module of claim 5, wherein, The distance between the LED chip and the Fresnel lens is 27 mm.

Images