CN115097672A

CN115097672A - Backlight module, image generation unit, head-up display and vehicle

Info

Publication number: CN115097672A
Application number: CN202210879051.0A
Authority: CN
Inventors: 陈伯纶; 陈芸霈; 庄觐懋
Original assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; Yecheng Optoelectronics Wuxi Co Ltd; General Interface Solution Ltd
Current assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; Yecheng Optoelectronics Wuxi Co Ltd; General Interface Solution Ltd
Priority date: 2022-07-25
Filing date: 2022-07-25
Publication date: 2022-09-23
Also published as: TW202405512A; TWI838802B

Abstract

The embodiment of the application relates to the technical field of display, and provides a backlight module, an image generation unit, a head-up display and a vehicle. The backlight module comprises a circuit board, a plurality of light-emitting elements, a plurality of reflectors and a plurality of condensing lenses. Each reflecting cover covers at least two light-emitting elements, all the light-emitting elements of each reflecting cover are defined as a light source group, a plurality of light source groups are arranged in an array of a plurality of rows and a plurality of columns, and the opening, closing and light-emitting brightness of all the light-emitting elements in each light source group can be independently controlled as a whole. Each condensing lens is aligned with one light source group. The backlight module has high brightness and high uniformity.

Description

Backlight module, image generation unit, head-up display and vehicle

Technical Field

The application relates to the technical field of display, in particular to a backlight module, an image generation unit, a head-up display and a vehicle.

Background

In the head-up display, an image generating unit is used for providing image light. The conventional image generation unit includes a backlight module and a liquid crystal display panel. In order to prevent the entire surface of the liquid crystal display panel from generating a dark corner, the image generating unit usually adopts a direct-type backlight module to emit light. However, although the conventional direct type backlight module can emit light on the whole surface, it also causes a problem of over brightness. In addition, the conventional backlight module is in a normal full-lighting state, so that the brightness value of a black picture is increased, and the contrast of the picture is reduced.

Disclosure of Invention

The present application provides a backlight module in a first aspect. The backlight module comprises:

a circuit board;

the light-emitting elements are arranged on the circuit board at intervals, and each light-emitting element is electrically connected with the circuit board;

the light source groups are arranged in an array of a plurality of rows and a plurality of columns, and the opening, the closing and the brightness of all the light emitting elements in each light source group can be controlled independently as a whole; and

and the plurality of condensing lenses are positioned on one side of the plurality of reflection covers, which is far away from the plurality of light-emitting elements, and each condensing lens is aligned with one light source group.

In the backlight module, the reflector is used for correcting the light-emitting angle of the light-emitting element and generating a light-gathering effect. The condensing lens is used for condensing the light emitted by the corresponding light-emitting element so as to amplify the light-emitting brightness of the light-emitting element, and further improve the light-emitting brightness of the backlight module. In addition, in the backlight module, the opening, closing and light emitting brightness of all the light emitting elements in each light source group can be independently controlled as a whole, so that the brightness of different areas of the backlight module can be correspondingly adjusted. Therefore, the effect of regional dynamic display is achieved, and the contrast ratio is better. In addition, compared with the conventional backlight module emitting light on the whole surface, the problem of over-brightness can be avoided.

A second aspect of the present application provides an image generation unit. The image generation unit includes:

a liquid crystal display panel for forming image light; and

the backlight module according to the first aspect is located on one side of the liquid crystal display panel and provides the liquid crystal display panel with backlight required for forming the image light.

The image generating unit includes the backlight module described in the first aspect, and therefore, the image generating unit has at least the same advantages as the backlight module described in the first aspect, and is not described in detail.

A third aspect of the present application provides a heads up display. This new line display includes:

an image generation unit according to the second aspect; and

a reflection assembly to reflect the image light to a projection medium for imaging.

The head-up display comprises the image generation unit according to the second aspect, and therefore, at least has the same advantages as the image generation unit according to the second aspect, and the details are not repeated.

A fourth aspect of the present application provides a vehicle. The vehicle includes:

a windshield; and

the heads-up display of a third aspect wherein the windshield is the projection medium.

The vehicle comprises a heads-up display according to the third aspect, and therefore has at least the same advantages as the heads-up display according to the third aspect, and will not be described in detail.

Drawings

Fig. 1 is a schematic structural diagram of a vehicle according to an embodiment of the present application.

Fig. 2A is a schematic structural diagram of the lamp panel, the reflector and the condenser lens of the image generating unit in fig. 1 assembled together.

Fig. 2B is a schematic cross-sectional view taken along line a-a of fig. 2A.

Fig. 3 is a perspective view of the image generation unit of fig. 1.

Fig. 4 is an exploded perspective view of the image generating unit of fig. 3.

Fig. 5 is a schematic plan view of the lamp panel in the image generating unit shown in fig. 4.

Fig. 6 is a plan view of the lamp panel and the condenser lens in the image generating unit shown in fig. 4.

Fig. 7 is a luminance chart obtained by simulation in a state where the light emitting elements of the image generating unit shown in fig. 4 are fully bright.

Fig. 8 is a luminance chart obtained by simulation in a state where 6 rows and 8 columns of light emitting elements in the middle area of the image generation unit shown in fig. 4 are lit.

Fig. 9 is a luminance chart obtained by simulation in a state where light emitting elements of 2 rows and 4 columns in the middle area of the image generation unit shown in fig. 4 are lit.

Fig. 10 is a luminance chart obtained by simulation in a state where the image generation unit shown in fig. 4 lights up the light emitting elements at intervals in the horizontal direction.

Fig. 11 is a luminance chart obtained by simulation in a state where the image generation unit shown in fig. 4 lights up the light emitting elements at intervals in the vertical direction.

Fig. 12 is a luminance graph obtained by simulation in a state where light emitting elements at both side edges and a central region of the image generation unit shown in fig. 4 are lit up.

Fig. 13 is a luminance chart obtained by simulation in a state where light emitting elements of diagonal regions of the image generation unit shown in fig. 4 are lit.

Fig. 14 is a luminance chart obtained by simulation of the image generation unit shown in fig. 4 in a state where the light emitting elements of the upper and lower edge regions are lit.

Fig. 15 is a luminance chart obtained by simulation in a state where the half-side area light emitting elements of the image generation unit shown in fig. 4 are turned on.

Description of the main element symbols:

vehicle 100

Windshield 110

Head-up display 120

Base 10

Image generation unit 20

Case 21

Cover 211

Frame body 212

First fastener 221

Second fastener 222

Liquid crystal display panel 23

Diffuser element 24

Spacer 25

Backlight module 26

Lamp panel 261

Circuit board 2611

Driving chip 2612

Connector 2613

Light emitting element 2614

Reflection cover 262

Condensing lens 263

Reflection assembly 30

First reflector 31

The second reflector 32

Eye E

Light outlet H1

Opening H2

Accommodating cavity R

First mounting hole MH1

Second mounting hole MH2

Light source group G

Line spacing dy

Column pitch dx

First direction X

Second direction Y

Image light L

Reflecting surface S

Light incident surface Sa

Light emergent surface Sb

Inclination angle beta

Distance Δ X

Detailed Description

Head Up Display (HUD) technology, also called head up display technology, has been increasingly used in the automotive, aerospace and marine fields in recent years. For example, the method can be applied to vehicles, and can also be applied to other vehicles such as airplanes, space flight and aviation aircrafts, ships and the like. For convenience of description, in the present application, a vehicle-mounted HUD is described as an example. It should be understood that this is not a limitation of the present application.

Specifically, the head-up display utilizes the principle of optical reflection, projects important driving related information (such as running speed, storage battery voltage, water tank temperature, engine speed, vehicle oil consumption, navigation route and the like) on a windshield, reflects the driving related information into eyes of a driver, assists the driver in driving the vehicle, avoids distraction caused by the driver leaning down to see an instrument panel in the driving process, improves driving safety factor, and can bring better driving experience.

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments.

Fig. 1 is a schematic structural diagram of a vehicle according to an embodiment of the present application. As shown in fig. 1, the vehicle 100 includes a vehicle body and a head-up display 120 located in the vehicle body. Only the windshield 110 of the vehicle body is exemplarily shown in fig. 1 and other parts of the vehicle body are omitted. Other components of the vehicle body include, for example, sensor systems, control systems, engine systems, etc. The sensor system includes, for example, a global positioning system, a radar system, and the like. The control system includes, for example, a steering unit for adjusting the traveling direction of the vehicle, a throttle controller for controlling the traveling speed of the vehicle, an engine controller, and the like.

The head-up display 120 includes a base 10, an image Generation Unit (PGU) 20 located in the base 10, and a reflection assembly 30 located in the base 10. The base 10 is located, for example, on a center console of the vehicle 100. The image generation unit 20 is configured to emit image light L. The reflection assembly 30 is used for reflecting the image light L emitted from the image generation unit 20 to the projection medium for imaging. The head-up display 120 is a Windshield 110 type head-up display (Windshield HUD, WHUD). Windshield 110 is the projection medium. WHUD is a HUD that displays necessary information in the line of sight of the driver using the windshield of the vehicle. Generally, a WHUD may be included in a vehicle.

The image generating unit 20 includes a backlight 26 and a liquid crystal display panel 23 located on a light emitting side of the backlight 26. The backlight module 26 is used for providing backlight to the liquid crystal display panel 23. The liquid crystal display panel 23 is used for receiving the backlight to form image light L, outputting various pictures, providing more information for the driver, and improving the driving experience. In some embodiments, the liquid crystal display panel 23 is, for example, 4.1inch, and the refractive index thereof is 1.52, but not limited thereto.

The reflective assembly 30 is positioned between the windshield 110 and the image generating unit 20. The reflective assembly 30 includes at least one mirror. In fig. 1, the reflection assembly 30 includes two mirrors, a first mirror 31 and a second mirror 32. The first mirror 31 is used to fold the optical path and the second mirror 32 is used to magnify the image. The first mirror 31 is located on the light exit side of the image generation unit 20, and reflects the image light L of the image generation unit 20 to the second mirror 32. The second reflecting mirror 32 is configured to reflect the image light L emitted from the first reflecting mirror 31 to the windshield 110, and after the image light L is reflected to the windshield 110, a target virtual image is generated in front of the windshield 110 and observed by the eyes E of the driver.

It should be noted that, since the windshield 110 is tilted, which may cause image distortion, at least one of the first reflecting mirror 31 and the second reflecting mirror 32 is a spherical mirror with adjustable position. In the embodiment shown in fig. 1, the first mirror 31 is a non-adjustable planar mirror, and the second mirror 32 is a adjustable curved mirror (e.g., a spherical mirror). By adjusting the position of the second mirror 32, the position of the image of the heads-up display 120 on the projection medium is adjusted, so that the image can be clearly and completely displayed, and the driver can clearly see the virtual image displayed by the HUD projection. The spherical Mirror is, for example, a free-form Concave Mirror (Freeform Concave Mirror) to enlarge an image and provide a further imaging distance.

In other embodiments, the first reflecting mirror 31 may be a spherical mirror with an adjustable position, the second reflecting mirror 32 may be a spherical mirror with an unadjustable position, and the position of the image on the projection medium of the HUD may be adjusted by adjusting the position of the first reflecting mirror 31, so as to display the image clearly and completely.

In other embodiments, the reflection assembly 30 is not limited to include two mirrors, for example, it may also include a third mirror, a fourth mirror, etc., and the mirrors in the reflection assembly 30 may be convex mirrors, or concave mirrors, or flat mirrors.

The image generation unit 20 further comprises a diffuser element 24 (shown in fig. 4) located between the liquid crystal display panel 23 and the backlight module 26. The diffusion element 24 is used for diffusing the light emitted from the backlight module 26 and then projecting the light to the liquid crystal display panel 23, so as to improve the uniformity of the light projected to the liquid crystal display panel 23. The diffusion member 24 is, for example, a diffusion film (diffuser film). The diffusion film is also called as light homogenizing plate, diffusion sheet, diffusion plate, etc.

In some embodiments, the diffuser element 24 is a bulk diffuser film based on PET and has a refractive index of approximately 1.49. Light sees through the diffusion barrier who uses PET as the substrate, can pass in the different medium of refracting index for many refraction, reflection and scattering's phenomenon take place for light, and correctable light becomes even area light source in order to reach the effect of optical diffusion, increases the light radiation area, promotes the degree of consistency of light. In other embodiments, the material of the diffuser element 24 is not limited thereto.

Referring to fig. 2A and fig. 2B, the backlight module 26 includes a lamp panel 261, a plurality of reflective covers 262, and a plurality of condensing lenses 263. The lamp panel 261 includes a circuit board 2611, a plurality of driving chips 2612 spaced on the circuit board 2611, and a plurality of light emitting elements 2614 spaced on the circuit board 2611. Circuit board 2611 is, for example, a printed circuit board. The plurality of driving chips 2612 and the plurality of light emitting elements 2614 are electrically connected to the circuit board 2611. The light emitting elements 2614 are, for example, light emitting diodes, for providing a light source path to the light source itself.

Specifically, the light emitting element 2614 may be a Lambertian light emitting diode which emits light at a current of 50mA, and the light emitting luminance is, for example, 17.4 lumens (lm), but is not limited thereto.

The plurality of driving chips 2612 are arranged in a line at intervals in the first direction X in a region of the circuit board 2611 near the edge. The plurality of light emitting elements 2614 are arranged in a plurality of columns at intervals in the first direction X and in a plurality of rows at intervals in the second direction Y next to the plurality of driving chips 2612. The second direction Y intersects the first direction X. The first direction X is perpendicular to the second direction Y in fig. 2A. In fig. 2A, six rows of light-emitting elements 2614 and their corresponding reflectors 262 and condenser lenses 263 are schematically depicted.

A plurality of reflective cups 262 are positioned on circuit board 2611. Each reflector 262 surrounds and covers at least two light emitting elements 2614. The reflective cover 262 is also called a reflective cup, a reflective cup or a reflective cup. The inner surface of each reflective cover 262 includes a reflective surface S to reflect light emitted from the light emitting element 2614. The reflective cover 262 is used to modify the light emitting angle of the light emitting element 2614 and generate a light condensing effect.

In some embodiments, the reflective surface S of the reflective cover 262 can be spherical, ellipsoidal, or concave with at least one free-form surface; alternatively, the reflecting surface S of the reflection cover 262 is formed by connecting a plurality of planes. In the embodiment shown in fig. 2B, the reflector 262 is a trapezoidal frustum-shaped reflector 262. The angle of inclination between the reflective surface S of the reflective cover 262 and the plane of the circuit board 2611 is β. The inclination angle is not less than 20 degrees (e.g., 20 degrees, 24 degrees, 30 degrees), so that light emitted from the light emitting element 2614 is reflected multiple times and then converged on the light incident surface Sa of the condenser lens 263. The reflective surface S may be a surface plated with a reflective layer, and the reflective layer is made of, for example, aluminum, and has a reflectivity of not less than 80% (e.g., 80%, 85%, 90%).

For convenience of description, all the light emitting elements 2614 covered by each reflective cover 262 are defined as one light source group G. That is, all the light emitting elements 2614 included in the same light source group G are located in the same reflective cover 262. In the embodiment shown in fig. 2B, each light source group G includes two light emitting elements 2614, and in other embodiments, the number of light emitting elements 2614 in one light source group G may be greater than two.

Specifically, the plurality of light source groups G are arranged in an array of rows and columns. All the light emitting elements 2614 in the same light source group G are connected in series, and all the light emitting elements 2614 in the same light source group G are electrically connected to the same driving chip 2612. The different light source groups G are connected in parallel. Alternatively, the light emitting elements 2614 corresponding to different light source groups G are mutually independent in electrical connection. Therefore, the on/off and the light-emitting brightness of all the light-emitting elements 2614 in each light source group G can be independently controlled as a whole by the driving chip 2612 electrically connected therewith, so that the light-emitting brightness of the region corresponding to each light source group G can be independently controlled. In addition, when the number of the light source groups G is greater than the number of the driving chips 2612, a plurality of light source groups G may be electrically connected to the same driving chip 2612. That is, different light source groups G can be controlled by the same driving chip 2612, but the on/off and the light emitting brightness of each of the different light source groups G are independently controlled.

In the embodiment of the present invention, the backlight module 26 includes a plurality of backlight regions (not shown), each of the backlight regions corresponds to one light source group G, the reflector 262 corresponding to the light source group G, and the condensing lens 263. The backlight module 26 may use a local dimming (local dimming) technique to provide a good backlight for the lcd panel 23. Specifically, the backlight module 26 can control the on/off and brightness of the light emitting elements 2614 in each light source group G through the driving chip 2612, so as to adjust the brightness and uniformity of each backlight region, and thus the brightness and uniformity of different image display regions of the liquid crystal display panel 23 can be adjusted.

The condensing lens 263 is located on the side of the reflector 262 away from the circuit board 2611. Each condensing lens 263 corresponds to one reflector 262, or each condensing lens 263 corresponds to one light source group G. The condensing lens 263 is used for condensing the light emitted from the light emitting element 2614 in the corresponding light source group G to amplify the light emitting brightness of the light emitting element 2614, thereby improving the light emitting brightness of the backlight module 26.

In a particular application, each of the condenser lenses 263 is one of a plano-convex lens, a biconvex lens, and a meniscus lens. Each of the condensing lenses 263 includes a light incident surface Sa facing the light emitting element 2614 and a light emitting surface Sb opposite to the light incident surface Sa, the light emitting surface Sb is a convex surface, and the curvatures of the convex surfaces of the condensing lenses 263 are different. Specifically, the curvature of the convex surface of the condensing lens 263 can be adjusted through simulation of optical software, so as to obtain the best effect of brightness and uniformity of different light emitting areas of the backlight module 26, and then the optical parameters of the condensing lens 263 are specifically set in an actual product.

Specifically, a lens whose optical surface is a part of a spherical surface is a spherical lens, or a spherical lens refers to a lens having a constant curvature from the center of the lens to the edge of the lens. The aspherical lens has a curvature that continuously changes from the center of the lens to the edge of the lens. In the embodiments of the present application, "curvature" refers to a degree of bending, and the curvature of a spherical surface can be represented by a curvature or a radius of curvature. The term "different curvatures" refers to the same curvatures, and in the embodiment of the present application, when the convex surfaces of the two condenser lenses are identical curved surfaces, the convex surfaces of the two condenser lenses are said to have the same curvatures. In addition, as long as the convex surfaces of the two condensing lenses are not completely the same curved surfaces, the convex surfaces of the two condensing lenses are said to have different curvatures, i.e. the curvatures are different.

In the embodiment shown in fig. 2, each condensing lens 263 is a plano-convex lens, and the light emitting surface Sb of each condensing lens 263 is a spherical surface, and the curvature radius of the spherical surface tends to increase in a direction from the center of the lens array to the edge of the lens array, or in a direction from the center of the array of the plurality of light source groups G to the edge of the array of the plurality of light source groups G, or in a direction from the center of the array of the plurality of light emitting elements 2614 to the edge of the array of the plurality of light emitting elements 2614.

In some embodiments, the number of light emitting elements 2614 is greater along the first direction X than the number of light emitting elements 2614 arranged along the second direction Y. That is, the first direction X is a long side of the array of the light emitting elements 2614, and the second direction Y is a short side of the array of the light emitting elements 2614. In the first direction X, the radius of curvature of the condensing lens 263 corresponding to the light emitting element 2614 near the edge is larger than the radius of curvature of the condensing lens 263 corresponding to the light emitting element 2614 near the center. For example, the radius of curvature of each of the condenser lenses 263 in the same column is equal. The radii of curvature of the condenser lenses 263 of the first and last columns are equal and are each larger than the radius of curvature of the condenser lenses 263 positioned between the first and last columns. In this way, the problem of uneven brightness in the display screen of the liquid crystal display panel 23 due to the first and last columns being far from the center of the display screen of the liquid crystal display panel 23 can be avoided.

In a specific embodiment, the material of each condensing lens 263 is Polycarbonate (PC), the refractive index of each condensing lens 263 is 1.56, the radius of curvature of the spherical surface of the condensing lens 263 in the first and last columns is 8.33mm, and the radius of curvature of the spherical surface of the condensing lens 263 in the middle column is 6.25 mm. In this way, by setting the curvature radii of the plurality of condensing lenses 263 to be different, an excellent effect of increasing the brightness and an excellent effect of high uniformity can be achieved.

In other embodiments, the radius of curvature of the condensing lenses 263 in the first and last columns is not limited to be adjusted, for example, the radius of curvature of the condensing lenses 263 in the first and last columns may be adjusted, so that the radius of curvature of the spherical surface tends to increase in a direction from the center of the lens array to the edge of the lens array. In addition, the curvature radius of the condensing lenses 263 in different rows may be adjusted so that the curvature radius of the spherical surface tends to become larger in a direction from the center of the lens array to the edge of the lens array. Similarly, the radius of curvature of the condenser lens 263 of one or more rows may be adjusted. Understandably, when the distribution of the plurality of focusing lenses is symmetrical, it is beneficial to make the backlight module 26 have symmetrical light-emitting distribution.

In other embodiments, when the condenser lens 263 is a lenticular lens or a meniscus lens, the optical parameters of the lenticular lenses in different rows (or different columns) can be adjusted to achieve the best brightness and uniformity for different light-emitting regions of the backlight module 26. For example, the curvatures of the light incident surface Sa of each lenticular lens are the same, and the curvatures of the light emitting surfaces Sb in different rows (or different columns) are different; alternatively, the curvatures of the light incident surface Sa of each meniscus lens are the same, and the curvatures of the light emitting surfaces Sb in different rows (or different columns) are different.

The plurality of light emitting elements 2614 are arranged at unequal intervals on the circuit board 2611. Correspondingly, the reflectors 262 are also arranged on the circuit board 2611 at unequal intervals, and the condenser lenses 263 are also arranged at unequal intervals. In addition, along the region of the circuit board 2611, the arrangement of the plurality of light emitting elements 2614, the arrangement of the plurality of reflectors 262 and the arrangement of the plurality of condenser lenses 263 all tend to change from dense to sparse. Specifically, the adjacent two condensing lenses 263 are spaced apart by a distance Δ X in the first direction X, and the distance Δ X gradually increases from the center of the circuit board 2611 to both sides in the first direction X.

It should be noted that, in the related art, the light emitting elements of the backlight module are uniformly and densely arranged, so that when the backlight module is applied to the HUD and different image information is displayed in different image areas of the liquid crystal display panel, the backlight emitted from the light emitting elements corresponding to the image areas at the edge of the liquid crystal display panel may be wasted. In the embodiment of the present invention, the light emitting elements 2614 are arranged at unequal intervals, especially, the light emitting elements 2614 are sparser in the edge region of the circuit board 2611 relative to the middle region, and the light emitted from the light emitting elements 2614 is converged by the reflector 262 and the condenser lens 263, and the area lighting technology is adopted, so that the effects of high brightness and high uniformity can be achieved by a small number of light emitting elements 2614.

Fig. 3 is a perspective view of the image generation unit of fig. 1. As shown in fig. 3, the image generating unit 20 further includes a housing 21 for accommodating the liquid crystal display panel 23, the diffusing element 24, and the condensing lens 263 and the reflection cover 262 in the backlight module 26.

Specifically, the housing 21 includes a cover 211 and a frame 212. A through hole (i.e., a light exit H1) is formed in the middle of the cover 211, and the light exit H1 is used for emitting the image light L. After the liquid crystal display panel 23 is partially housed in the case 21, its display surface is exposed from the light outlet H1.

Frame 212 is a generally hollow cylinder. Frame 212 in fig. 3 is a hollow tetrahedron. Flanges extend from opposite ends of frame 212, wherein the flange of frame 212 adjacent to cover 211 is provided with a first mounting hole MH1, and correspondingly, cover 211 is also provided with a first mounting hole MH1, so that cover 211 and frame 212 can be connected by first fastening member 221. The first fastening member 221 is, for example, a screw. In addition, frame 212 has a second mounting hole MH2 near the flange of lamp panel 261, and correspondingly, circuit board 2611 has a second mounting hole MH2, so that cover 211 and frame 212 can be connected by second fastener 222. The second fastener 222 is, for example, a screw.

Additionally, lamp panel 261 also includes a connector 2613. The connector 2613 is disposed adjacent to the plurality of driving chips 2612 at an edge region of the circuit board 2611. After the circuit board 2611 is connected to the frame 212, the driving chips 2612 and the connectors 2613 are not accommodated in the frame 212 but exposed from the frame 212. The connector 2613 is electrically connected to the plurality of driving chips 2612 and the liquid crystal display panel 23. In an embodiment, the connector 2613 is, for example, a power connector 2613, which is used to provide power to the liquid crystal display panel 23 and the plurality of light emitting elements 2614, but is not limited thereto.

Fig. 4 is an exploded perspective view of the image generating unit of fig. 3. As shown in fig. 4, a first mounting hole MH1 is respectively disposed at four corners of the cover 211, and a first mounting hole MH1 is respectively disposed at four corners of the frame 212 near the flange of the cover 211, so that the cover 211 and the frame 212 are mechanically connected at corresponding positions. The frame body 212 and the cover body 211 together define a housing chamber R. Frame 212 includes an opening H2 near lamp panel 261 and opposite to light outlet H1. The accommodating chamber R communicates with the light outlet H1 and the opening H2. The plurality of condensing lenses 263, the plurality of reflectors 262 and the plurality of light emitting elements 2614 are sequentially accommodated in the accommodating cavity R, and the circuit board 2611 closes the opening H2 and is mechanically connected with the frame 212.

The image generation unit 20 further comprises a spacer 25. The spacer 25 is square-shaped and serves to elevate the diffusion element 24 and the liquid crystal display panel 23. The cushion block 25 is accommodated in the accommodating chamber R. The diffusion element 24 and the liquid crystal display panel 23 are sequentially placed on the pad 25 and accommodated in the accommodating cavity R. The lcd panel 23 is partially accommodated in the accommodating cavity R, and one side of the display screen thereof is exposed from the light outlet H1.

The plurality of condensing lenses 263 is a single integral layer. The plurality of condensing lenses 263 are integrally molded by injection, for example, or are molded by numerical control machining.

In addition, the plurality of reflective covers 262 is also one integral layer. The entire layer of the plurality of reflection covers 262 includes a plurality of recesses, each of which is formed to correspond to one of the reflection covers 262. Specifically, each of the recesses has a substantially trapezoidal frustum shape and opposite sides of each of the recesses are perforated. Wherein, the opening of each recess near lamp panel 261 is closed by circuit board 2611, so that each bowl 262 surrounds at least two light emitting elements 2614. The opening of each recess close to the condenser lens 263 is closed by the condenser lens 263, so that the light emitted from the light emitting element 2614 is reflected by the reflective cover 262 to the light incident surface Sa of the condenser lens 263.

Fig. 5 is a schematic plan view of the lamp panel in the image generating unit shown in fig. 4. Fig. 6 is a plan view of the lamp panel and the condenser lens in the image generating unit shown in fig. 4. In the embodiment of the present invention, the light emitting elements 2614 are disposed at unequal intervals, and the condensing lenses 263 are disposed at unequal curvatures, and cooperate with the area lighting technology to make the backlight module 26 have high brightness and high uniformity. The arrangement of the plurality of light emitting elements 2614 and the plurality of condensing lenses 263 will be specifically described below with reference to fig. 5 and 6.

As shown in fig. 5, there are six driving chips 2612 on lamp panel 261, and each light source group G includes two light emitting elements 2614. The plurality of light source groups G are arranged in M columns along the X axis and in N rows along the Y axis (M is an integer greater than or equal to 2, and N is an integer greater than or equal to 2). In fig. 5, the light source group G is arranged in 6 rows and 12 columns (M is 12, N is 6), and a total of 144 light emitting elements 2614. The light emitting elements 2614 in each two columns of light source groups G are correspondingly connected with one driving chip 2612. The line spacing between any two adjacent light source groups G in the same line is defined as dy. In the same column, the column pitch between any two adjacent light source groups G is dx. At least one of dy and dx tends to become larger in a direction from the center of the array toward the edge of the array. That is, it may be that dx becomes progressively larger in a direction from the center of the array toward the edge of the array; or dy is gradually increased from the center of the array to the edge of the array; alternatively, in a direction from the center of the array to the edge of the array, dx gradually becomes larger while dy gradually becomes larger.

In fig. 5, the array of the plurality of light emitting elements 2614 is symmetrically distributed in both the X-axis direction and the Y-axis direction, and gradually increases in size from the origin of coordinates to both dx and dy. In the embodiment of the present application, "gradually increasing" and "increasing trend" refer to an overall trend of the distance from small to large, which allows the distance to be maintained at a constant value during the process of changing from small to large.

As shown in fig. 6, the plurality of condenser lenses 263 are arranged in N rows and M columns, wherein the first condenser lens 263 to the last (i.e., the M-th) condenser lens 263 in the first row are named as G11, G12, … G1M in sequence; by analogy, the first condensing lens 263 of the nth row to the last (i.e., mth) condensing lens 263 of the nth row are named GN1, GN2 …, GNM, respectively. In fig. 6, the plurality of condensing lenses 263 are arranged in 6 rows and 12 columns (M is 12, and N is 6). A rectangular coordinate system is established with the center of the array of the plurality of condensing lenses 263 as the origin of coordinates, the row direction as the X axis, and the column direction as the Y axis. The plurality of condensing lenses 263 are axisymmetric with respect to the X-axis and are axisymmetrically distributed with respect to the Y-axis. The distances between the plurality of condensing lenses 263 are gradually increased from the origin of coordinates to the X-axis positive direction. The distances between the plurality of condensing lenses 263 are gradually increased from the coordinate origin to the Y-axis positive direction.

In a specific embodiment, the position of the condensing lens 263 can be expressed by the following formula. For the first quadrant and the fourth quadrant, the abscissa value (unit mm) of each condensing lens 263 is 9.042A-7.6, where a is the number of columns, and a in fig. 6 has a value range of 7, 8, 9, 10, 11, 12. Understandably, in the second and third quadrants, the abscissa value of each condenser lens 263 can be mirrored according to the symmetrical relationship. With respect to the ordinate value of each condenser lens 263, the ordinate value (unit mm) of each condenser lens 263 in the 7 th column is-9.2B + 32.2; the ordinate value (unit mm) of each of the condenser lenses 263 of the 8 th column and the 9 th column is-9.485B + 33.2; the ordinate value (unit mm) of each condenser lens 263 in column 10 is-9.714B + 34; the ordinate value (unit mm) of each of the condenser lenses 263 of the 11 th column and the 12 th column is-9.994B + 34.98. Wherein B is the number of rows, and the numeric ranges of B in fig. 6 are 1, 2, 3, 4, 5, and 6. Understandably, the number and pitch arrangement of the condenser lenses 263 are not limited thereto.

The brightness and uniformity of the image generating unit 20 according to the embodiment of the present application will be described with reference to fig. 7 to 15. Fig. 7 to 15 are obtained by simulation with optical software (such as Light Tools). Specifically, the luminance uniformity (display area-100%) of the resulting image generating unit 20 was 66.8%, and the center luminance was 835000 nit. The horizontal field angle is +/-20.5 degrees, and the vertical field angle is +/-4 degrees. The transmittance of the liquid crystal display panel 23 is 0.072, and the reflectance of the reflection assembly 30 is 0.9 ³ The transmittance of the cover 211 is 0.8, the reflectance of the windshield 110 is 0.3, and the estimated brightness calculated is 835000 × 0.072 × 0.9 ³ 0.8 × 0.3 ═ 10518 nit. It can be seen that the image generation unit 20 of the embodiment of the present application has high brightness (the brightness of the emitted light of the conventional image generation unit is much less than ten thousand)nit)。

As shown in fig. 7, when all the light source groups G are turned on, the central luminance of the plurality of regions is higher than 80 million, and the luminance distribution in the whole frame is relatively uniform. In addition, as shown in fig. 8 to fig. 15, the backlight module 26 may be collocated with the driving chip 2612 according to the position of the light source group G, so that the liquid crystal display panel 23 presents different image display areas, which is not limited to full-screen display.

For example, a plurality of light source groups G in the middle area in lamp panel 261 may be controlled to emit light. Fig. 8 is a luminance graph obtained by lighting the light-emitting elements 2614 in 6 rows and 8 columns in the intermediate region of the image generation unit 20, and fig. 9 is a luminance graph obtained by simulation in a state where the light-emitting elements 2614 in 2 rows and 4 columns in the intermediate region of the image generation unit 20 are lit.

Alternatively, a plurality of light source groups G in different regions of lamp panel 261 may be controlled at intervals to emit light. Here, fig. 10 to 15 are luminance graphs obtained by simulation of the image generation unit 20 in a state where the light emitting elements 2614 are lit at horizontal direction intervals, in a state where the light emitting elements 2614 are lit at vertical direction intervals, in a state where the light emitting elements 2614 at both side edges and the center region are lit, in a state where the light emitting elements 2614 at diagonal regions are lit, in a state where the light emitting elements 2614 at upper and lower edge regions are lit, and in a state where the light emitting elements 2614 at half-side regions are lit, respectively. As can be seen from fig. 7 to 15, the image generating unit 20 has high brightness and high uniformity. Understandably, the area lighting pattern that the image generation unit 20 can realize is not limited to that shown in fig. 7 to 15.

To sum up, among the backlight unit of this application embodiment, through setting up the bowl with light emitting component's light convergence to condensing lens to increase light brightness through condensing lens, further condensing lens's light demonstrates the effect of draft degree of consistency and high luminance behind the diffusion element to the liquid crystal display panel. In addition, in this application embodiment, backlight unit can be according to arranging of light source group, through the local technique of lighting up, reaches regional dynamic display's effect for HUD can be effectively energy-conserving, and has the contrast of preferred. In addition, compared with the conventional backlight module emitting light on the whole surface, the problem of over-brightness can be avoided.

Although the present application has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the present application.

Claims

1. A backlight module, comprising:

a circuit board;

2. The backlight module according to claim 1, wherein the light emitting elements are arranged on the circuit board at unequal intervals.

3. The backlight module according to claim 2, wherein the row spacing between any two adjacent light source groups in the same row is defined as dy; defining the column spacing of any two adjacent light source groups in the same column as dx; wherein at least one of dy and dx is increasing in a direction from the center of the array to the edge of the array.

4. The backlight module according to any one of claims 1-3, wherein each of the condensing lenses is one of a plano-convex lens, a biconvex lens and a meniscus lens; each condensing lens comprises a light incident surface facing the light emitting element and a light emergent surface opposite to the light incident surface, the light emergent surface is a convex surface, and the curvatures of the convex surfaces of the condensing lenses are different.

5. The backlight module as claimed in claim 4, wherein each of the condensing lenses is a plano-convex lens, the light emitting surface of each of the condensing lenses is a spherical surface, and a curvature radius of the spherical surface is increased in a direction from a center of the array to an edge of the array.

6. An image generation unit, characterized by comprising:

a liquid crystal display panel for forming image light; and

the backlight module according to any one of claims 1 to 5, located at one side of the liquid crystal display panel and providing the liquid crystal display panel with a backlight required for forming the image light.

7. The image generation unit of claim 6, further comprising a housing; the shell comprises a light outlet for emitting the image light, an open hole opposite to the light outlet and an accommodating cavity for communicating the light outlet and the open hole; the plurality of light-emitting elements, the plurality of reflection covers and the plurality of condensing lenses are accommodated in the accommodating cavity, and the circuit board closes the opening; the liquid crystal display panel part is accommodated in the accommodating cavity.

8. The image generation unit according to claim 6 or 7, characterized in that the image generation unit further comprises a diffusion element located between the liquid crystal display panel and the plurality of condenser lenses.

9. A heads-up display, comprising:

an image generation unit according to any one of claims 6 to 8; and

10. A vehicle, characterized by comprising:

a windshield; and

the heads up display of claim 9 wherein the windshield is the projection medium.