Backlight module for head-up display

Abstract

A backlight module for a head-up display includes an LED light source, a rectangular total reflection collimating lens is arranged on the LED light source, and a double fly-eye lens, a relay lens, a rotatable field lens and a diffusion plate are sequentially arranged at intervals on the rear side of the total reflection collimating lens, and the rotation angle of the diffusion plate is consistent with the rotation angle of the field lens. Through a specific combination of the total reflection collimating lens, the double fly-eye lens, the relay lens, the rotatable field lens and the diffusion plate, the output light angle γ has a certain tilt effect and the output cone angles α and β are asymmetric, which can match the human eye observation area to the greatest extent, so that all the light falls within the human eye observation area, and the utilization rate of the lighting beam is maximized.

Description

Technical Field

[0001] The invention relates to a vehicle-mounted head-up display, and in particular to a backlight module used for the vehicle-mounted head-up display. Background Art

[0002] The main function of the car's head-up display is to allow car owners to no longer have to lower their heads to look at their mobile phones or dashboards. It can project these data onto the front windshield, allowing car owners to intuitively see some driving information they need to know. It can be seen that the working principle of the car's head-up display is similar to that of a projector, which is to project the desired image onto the front windshield, and what our eyes see is like the image floating in front of the vehicle.

[0003] When the head-up display is working, it needs the assistance of the backlight module. In the usage scenario of the head-up display, it is generally stipulated that the human eye observes the image transmitted by the head-up display in a certain rectangular area, and the backlight illumination beam is required to be emitted at an angle. Therefore, the backlight illumination structure with an asymmetric emission cone angle and the feature of the illumination beam having a certain inclined emission angle can match the human eye observation area to the greatest extent, thereby maximizing the utilization rate of the illumination beam. Summary of the invention

[0004] The present invention aims to provide a backlight module for a head-up display with compact structure, low power consumption, high and uniform brightness, high light beam utilization rate, and an illumination light beam having an asymmetric emission cone angle and a certain inclined emission light angle.

[0005] A backlight module for a head-up display described in the present invention includes an LED light source, on which a rectangular total reflection collimating lens is arranged, and on the rear side of the total reflection collimating lens, a double compound eye lens, a relay lens, a rotatable field lens and a diffuser plate are sequentially arranged at intervals, wherein the rotation angle of the diffuser plate is consistent with the rotation angle of the field lens.

[0006] In a backlight module of a head-up display described in the present invention, light emitted by an LED light source is introduced into a total reflection collimating lens. Since the total reflection collimating lens is in a trumpet shape and its two end faces are both rectangular end faces, the introduced LED light beam will have different emission widths in the X direction and the Y direction, so that the light beam derived from the total reflection collimating lens will have different widths D1 and D2 in the Y direction and the X direction, and the light beams D1 and D2 of different widths are emitted in parallel. The parallel light beams directly enter the front surface of the double compound eye lens and are converged by each small lens unit on the double compound eye lens to form an image on the rear surface of the double compound eye lens, thereby dividing a light source into multiple light sources, which are then overlapped and illuminated on a diffusion plate by a subsequent assembly composed of a relay lens and a field lens to form a rectangular illumination light spot with uniform illumination. Since the angle of the field lens is adjustable, it can be The angle of the emergent light emitted by the field mirror is adjusted so that the emergent light angle γ has a certain tilt effect. At the same time, the aspect ratio of the emergent surface of the total reflection collimating lens can be changed to adjust the emergent cone angles β and α in the XZ plane and the YZ plane, so as to achieve the asymmetry of the emergent cone angle. It can be seen that through the specific combination of the total reflection collimating lens, the double compound eye lens, the relay lens, the rotatable field mirror and the diffuser plate, the emergent light angle γ can have a certain tilt effect and the emergent cone angles α and β can be asymmetric, which can match the human eye observation area to the greatest extent, so that all the light falls within the human eye observation area, thereby maximizing the utilization rate of the illumination light beam; in addition, the relay lens is equivalent to an integrating device, which can superimpose the light beams emitted by each small lens unit and project them into the area to be illuminated, thereby achieving high uniformity and high backlight utilization rate. The backlight module has a compact structure, occupies a small space, and has low power consumption. Through the combined effect of a total reflection collimating lens, a double compound eye lens, a relay lens, and a rotatable field lens, the emitted light has high brightness and is uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram of the structure of the present invention.

[0008] Figure 2 It is a schematic diagram of the XZ plane optical path of the present invention.

[0009] Figure 3 It is a schematic diagram of the YZ plane optical path of the present invention. DETAILED DESCRIPTION

[0010] A backlight module for a head-up display, such as Figures 1 to 3 As shown, it includes an LED light source, on which a rectangular total reflection collimating lens 1 is arranged, and on the tail side of the total reflection collimating lens 1, a double compound eye lens 2, a relay lens 3, a rotatable field lens 4 and a diffuser plate 5 are sequentially arranged at intervals, and the rotation angle of the diffuser plate 5 is consistent with the rotation angle of the field lens 4.

[0011] The rotation angle of the field lens 4 is -15°~+15°, such as -15°, -10°, -5°, 0°, 5°, 10° or 15°.

[0012] The double compound eye lens 2 is located at the front focal plane of the relay lens 3, and the field lens 4 is located at the rear focal plane of the relay lens 3, which can ensure that the backlight module has a telecentric structural feature and ensure that the brightness of the image in each field of view within the human eye observation area is consistent.

[0013] The distance between the double fly-eye lens 2 and the total reflection collimating lens 1 is 3 mm to 5 mm, such as 3 mm, 3.5 mm, 4 mm, 4.5 mm or 5 mm.

[0014] The distance between the diffusion plate 5 and the field lens 4 is 2 mm to 3 mm, such as 2 mm, 2.5 mm or 3 mm.

[0015] The LED light source comprises a PCB board 6 , and the LED lamp 7 is mounted on the PCB board 6 . The LED lamp 7 is butted against a small-sized end of the total reflection collimating lens 1 , so that the light source is incident from the small-sized end of the total reflection collimating lens 1 .

[0016] Through the above technical scheme, the output light angle γ can have a certain tilt effect and the output cone angles α and β can be made asymmetric, which can match the human eye observation area to the greatest extent, so that all the light falls within the human eye observation area, thereby maximizing the utilization rate of the illumination beam.

Claims

1. A backlight module for a head-up display, characterized in that: The invention comprises an LED light source, on which a rectangular total reflection collimating lens (1) is arranged, and on the rear side of the total reflection collimating lens (1) a double compound eye lens (2), a relay lens (3), a rotatable field lens (4) and a diffusion plate (5) are sequentially arranged at intervals, wherein the rotation angle of the diffusion plate (5) is consistent with the rotation angle of the field lens (4).

2. The backlight module of a head-up display according to claim 1, characterized in that: The rotation angle of the field lens (4) is -15° to +15°.

3. A backlight module for a head-up display according to claim 1 or 2, characterized in that: The double compound eye lens (2) is located at the front focal plane of the relay lens (3), and the field lens (4) is located at the back focal plane of the relay lens (3).

4. A backlight module for a head-up display according to claim 1 or 2, characterized in that: The distance between the double compound eye lens (2) and the total reflection collimating lens (1) is 3 mm to 5 mm.

5. The backlight module of a head-up display according to claim 3, characterized in that: The distance between the double compound eye lens (2) and the total reflection collimating lens (1) is 3 mm to 5 mm.

6. A backlight module for a head-up display according to claim 1, 2 or 5, characterized in that: The distance between the diffusion plate (5) and the field lens (4) is 2 mm to 3 mm.

7. A backlight module for a head-up display according to claim 1, 2 or 5, characterized in that: The LED light source comprises a PCB board (6), an LED lamp (7) is mounted on the PCB board (6), and the LED lamp (7) is butt-jointed with a small-sized end of a total reflection collimating lens (1).

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