Backlight module and display device

Abstract

A backlight module (2) and a display device comprising the backlight module (2). The backlight module (2) comprises a back frame (21), a light source (22), a diffusion plate (23), and a sleeve (24). The diffusion plate (23) is arranged on the back frame (21) and is located on a light emitting side of the light source (22). The sleeve (24) is arranged on the back frame (21) and passes, in its axial direction, through a lamp board (221) and the diffusion plate (23). The diffusion plate (23) has a plurality of printed dots (231), and the diffusion plate (23) is defined to have a blank area (232) for the sleeve (24) to pass through, and a first area (233) surrounding the blank area (232). The first area (233) comprises a high-density area (233a) and a low-density area (233b), there is no printed dots (231) in the blank area (232), and the printed dots (231) in the high-density area (233a) have a distribution density greater than the average distribution density in the low-density area (233b). By means of the design of different distribution densities of the printed dots (231), halo generated due to the provision of the sleeve (24) is overcome, thereby improving the light emission uniformity of the entire light emitting surface and the optical quality.

Description

Backlight module and display device Technical Field

[0001] This invention relates to an optical device, and more particularly to a backlight module and display device. Background Technology

[0002] Driver distraction and fatigue are major causes of vehicle accidents. A Driver Monitoring System (DMS) can add an extra layer of protection for driving safety. By mounting cameras on the dashboard, the DMS collects facial movement data of the driver, such as blinking, gaze direction, and head movements, to monitor and detect the driver's behavior and physiological state. When abnormal data is detected, it issues warning signals and activates driver assistance systems, improving driving safety and reducing the accident rate.

[0003] When a lens is mounted on the dashboard, balancing the lens's field of view with the dashboard's optical quality is a goal that relevant businesses urgently need to strive for. Summary of the Invention

[0004] Therefore, the objective of this invention is to provide a backlight module that improves light emission uniformity and optical quality.

[0005] The backlight module of the present invention includes a back frame, a light source, a diffuser plate, and a sleeve. The light source includes a lamp plate disposed on the back frame and a plurality of light-emitting elements disposed on the lamp plate. The diffuser plate is disposed on the back frame and located on the light-emitting side of the light source. The sleeve is disposed on the back frame and extends through the lamp plate and the diffuser plate along its axial direction. The diffuser plate has a plurality of printed dots on its surface, and the diffuser plate is defined to have a blank area for the sleeve to pass through, and a first area surrounding the blank area. The first area includes at least one high-density area and a low-density area. There are no printed dots in the blank area. The distribution density of the printed dots in the low-density area decreases from the vicinity of the blank area to the direction away from the blank area. The distribution density of the printed dots in the high-density area is greater than the average distribution density of the low-density area.

[0006] Another technical aspect of the present invention is that the light source has a first lamp area and a second lamp area with light-emitting elements arranged at different intervals. The light-emitting elements in the first lamp area are arranged at equal intervals with a first interval, and the light-emitting elements in the second lamp area are arranged at equal intervals with a second interval. The first interval is greater than the second interval, and the second lamp area corresponds to the high-density area of ​​the diffuser plate.

[0007] Another technical aspect of the present invention is that the diffuser plate is further defined to have a second region surrounding the first region, wherein there are no printed dots in the second region.

[0008] Another technical aspect of the present invention is that the back frame includes a bottom plate portion and a surrounding portion disposed around the periphery of the bottom plate portion, and the sleeve is disposed on the bottom plate portion and extends unidirectionally away from the bottom plate portion.

[0009] Another technical aspect of the present invention is that the back frame includes a bottom plate portion and a surrounding portion disposed around the periphery of the bottom plate portion, and the sleeve is disposed on the bottom plate portion and extends bidirectionally away from the bottom plate portion.

[0010] Another technical aspect of the present invention is that the outer surface of the sleeve has a reflectivity of 92% or higher.

[0011] Another technical aspect of the present invention is that the printed dots are disposed on a light-incident surface of the diffuser plate, and the light-incident surface faces the lamp plate.

[0012] Another technical aspect of the present invention is that the sleeve has an internal thread.

[0013] Another technical aspect of the present invention is that the backlight module further includes a light-shielding member disposed on the sleeve.

[0014] Another technical aspect of the present invention is that the backlight module further includes a light-shielding member that is fitted around the sleeve. The light-shielding member has an annular portion fitted on the sleeve, a top edge portion that extends radially inward from the annular portion and abuts against the top edge of the sleeve, and a pressing portion that extends radially outward from the annular portion. The annular portion abuts against the outer peripheral surface of the sleeve.

[0015] Another technical aspect of the present invention is that the backlight module further includes a light-shielding member that is fitted around the sleeve. The light-shielding member has an annular portion fitted on the sleeve, a top edge portion extending radially outward from the annular portion, and a pressing portion extending from the top edge portion. The annular portion abuts against the inner circumferential surface of the sleeve, and the end edge of the sleeve is covered by the annular portion, the top edge portion, and the pressing portion.

[0016] Another technical aspect of the present invention is that the backlight module further includes at least one optical film, which is disposed between the diffuser plate and the light shielding member, and has a perforation corresponding to the sleeve.

[0017] Another object of the present invention is to provide a display device comprising a backlight module as described above, and a display panel disposed on the backlight module.

[0018] Another object of the present invention is to provide a display device comprising a backlight module as described above, and a display panel disposed on the backlight module, the display panel resting on the light shield.

[0019] The advantage of this invention is that, by using the design of different distribution densities of the printed dots on the diffuser plate, the amount of light emitted after passing through the high-density area can be reduced, overcoming the halo problem caused by the sleeve, thereby improving the uniformity of light emission and optical quality of the overall light-emitting surface. Attached Figure Description

[0020] Figure 1 is an exploded perspective view of a preferred embodiment of the backlight module of the present invention.

[0021] Figure 2 is a schematic diagram illustrating the dot distribution of a diffuser plate;

[0022] Figure 3 is a schematic diagram, which is an enlarged view of the area shown in the box in Figure 1, illustrating that the light-emitting elements in different areas have different spacing.

[0023] Figure 4 is a schematic diagram illustrating the relationship between the dot distribution of the diffuser plate and the corresponding positions of light-emitting elements with different densities;

[0024] Figure 5 is a partial enlarged view illustrating the structure of a sleeve;

[0025] Figure 6 is a partial enlarged view illustrating another form of the sleeve;

[0026] Figure 7 is a partial enlarged view of a preferred embodiment of the display device of the present invention;

[0027] Figure 8 is a partial enlarged view illustrating a second form of a light-shielding component; and

[0028] Figure 9 is a partial enlarged view illustrating the third form of the light-shielding component. Detailed Implementation

[0029] The features and technical content of the related patent applications of this invention will be clearly presented in the following detailed description of the preferred embodiments with reference to the accompanying drawings. Before proceeding with the detailed description, it should be noted that similar elements are represented by the same numbers. The directional terms mentioned in the following embodiments, such as up, down, left, right, front, back, bottom, and top, are only for reference to the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the invention.

[0030] In the following description, the terms "about," "substantially," "roughly," or "same" generally indicate a range within 10%, 5%, 3%, 2%, 1%, or 0.5% of a given value. The quantities given here are approximate, meaning that the terms "about," "substantially," "roughly," or "same" may be implied even without specific mention of them.

[0031] Referring to Figure 1, a preferred embodiment of the backlight module 2 of the present invention is shown, comprising a back frame 21, a light source 22, a diffuser plate 23, and a sleeve 24. The light source 22 includes a lamp plate 221 disposed on the back frame 21 and a plurality of light-emitting elements 222 disposed on the lamp plate 221. The diffuser plate 23 is disposed on the back frame 21 and located on the light-emitting side of the light source 22. The sleeve 24 is disposed on the back frame 21, and the sleeve 24 passes through the lamp plate 221 and the diffuser plate 23 along its axial direction. Referring to Figure 2, a partial area of ​​the diffuser plate 23 adjacent to the sleeve 24 (see Figure 1) is shown. The surface of the diffuser plate 23 has a plurality of printed dots 231, defining a blank area 232 for the sleeve 24 to pass through, and a first area 233 surrounding the blank area 232. The first region 233 includes at least one high-density region 233a and one low-density region 233b. The blank region 232 contains no printed dots 231. The distribution density of the printed dots 231 in the low-density region 233b decreases from the vicinity of the blank region 232 towards the distance from it. The distribution density of the printed dots 231 in the high-density region 233a is greater than the average distribution density in the low-density region 233b. By using the design of different distribution densities of the printed dots 231 on the diffuser plate 23, the amount of light emitted after passing through the high-density region 233a can be reduced, overcoming the halo problem caused by the sleeve 24. Furthermore, the dot distribution trend in the low-density region 233b creates a fogging effect on the light-emitting surface near the sleeve 24, thereby improving the overall light emission uniformity and optical quality of the emitting surface.

[0032] It should be noted that in this embodiment, the backlight module 2 is used in a vehicle's Driver Monitoring System (DMS), and therefore is typically installed on the dashboard. The sleeve 24 is used to mount a camera lens. To avoid the camera lens being obstructed or interfered with by the steering wheel, the sleeve 24 is positioned upwards rather than in the exact center of the overall structure. Of course, the position of the sleeve 24 may vary depending on the actual usage environment and is not limited to that disclosed in this embodiment. The following will describe the detailed structure of this embodiment.

[0033] Referring to Figure 3, which is an enlarged view of the area framed in Figure 1, the light source 22 has a first lamp area 22a and a second lamp area 22b with light-emitting elements 222 arranged at different intervals. The light-emitting elements 222 in the first lamp area 22a are arranged at equal intervals with a first interval D1, and the light-emitting elements 222 in the second lamp area 22b are arranged at equal intervals with a second interval D2. The first interval D1 is greater than the second interval D2, meaning the light-emitting elements 222 in the second lamp area 22b are arranged at a higher density. More specifically, the second lamp area 22b is the area located near the sleeve 24. Comparing the number of light-emitting elements 222 per unit area of ​​the lamp panel 221, since the number of light-emitting elements 222 per unit area near the sleeve 24 is less than the number of light-emitting elements 222 per unit area near the overall central area, the luminance near the sleeve 24 is slightly lower than that of the overall central area. Therefore, a higher density of light-emitting elements 222 can be used for supplemental lighting. Because the light emitted by the high-density light-emitting elements 222 will create a bright halo effect in specific areas, the high-density area 233a of the diffuser plate 23 corresponds to the second lamp area 22b, as shown in Figure 4. This atomizes the light in the second lamp area 22b, and the combination of the two improves the overall light emission uniformity of the backlight module. More specifically, in Figure 4, the width of the arrow represents the amount of light. Because the second lamp area 22b has a higher density of light-emitting elements 222, it produces more light, hence the wider arrow. The first lamp area 22a has a lower density of light-emitting elements 222, producing less light, hence the thinner arrow. Through the density distribution of the printed dots 231 in the high-density area 233a and the low-density area 233b of the diffuser plate 23, the amount of light is adjusted to be uniform after passing through the diffuser plate 23, thereby improving the light emission uniformity.

[0034] Meanwhile, to improve the brightness near the sleeve 24, the outer surface of the sleeve 24 can also be selected with a color with a reflectivity of 92% or higher (in this embodiment, the outer surface of the sleeve 24 is white), and the light is reused through the reflection effect of the outer surface of the sleeve 24. When the light-emitting surface near the sleeve 24 is too bright due to the reflection of light by the sleeve 24, especially when the outer surface of the sleeve 24 is white, the excessive brightness is more obvious. At this time, the dot distribution trend of the low-density area 233b can be used to create a fogging effect on the light-emitting surface near the sleeve 24, and the amount of light emitted can be reduced after the light passes through the high-density area 233a (as shown by the narrowing of the arrow in Figure 4), thus overcoming the halo problem caused by the setting of the sleeve 24, thereby improving the uniformity of the light-emitting surface of the overall backlight module.

[0035] Referring to Figure 2, the diffuser plate 23 is defined to also have a second region 234 surrounding the first region 233. Since the second region 234 does not require adjustment of light brightness, it does not contain the printed dots 231. It should be noted that the first region 233 of the diffuser plate 23 of the present invention is the portion surrounding the blank region 232 with printed dots 231. In one embodiment, the distribution of the printed dots 231 can be selected to extend from the blank region 232 to the edge of the entire diffuser plate 23. However, in this embodiment, the second region 234 surrounds the periphery of the low-density region 233b, and there are no printed dots in the second region 234. That is, the printed dots 231 of the low-density region 233b are only distributed to the boundary between the first region 233 and the second region 234, and do not extend to the edge of the entire diffuser plate 23.

[0036] Referring to Figures 2 and 5, the printed dots 231 are disposed on a light-incident surface 230 of the diffuser plate 23, which faces the lamp plate 221. The location of the printed dots 231 on the light-incident surface 230 prevents them from rubbing against other films after assembly. As shown in Figure 5, the back frame 21 includes a base plate portion 211 and a surrounding portion 212 disposed around the periphery of the base plate portion 211. The sleeve 24 is disposed on the base plate portion 211. In some embodiments, the sleeve 24 extends unidirectionally away from the base plate portion 211, and this unidirectionally extending sleeve 24 can serve as a component for fixing the diffuser plate 23 and other optical films. The sleeve 24 can be formed by directly punching the base plate portion 211, or it can be formed first and then riveted to the base plate portion 211. In other embodiments, as shown in FIG. 6, the sleeve 24 extends bidirectionally away from the base plate portion 211. In actual implementation, the shape of the sleeve 24 can be selected according to the type of the camera lens 90 or the installation environment of the backlight module 2. The camera lens 90 can be placed inside the sleeve 24 as shown in FIG. 5, and then fixed inside the sleeve 24 by other sealing elements 91. Alternatively, as shown in FIG. 6, the sleeve 24 can have internal threads to connect the camera lens 90 (not shown in the figure) by screwing, thereby simplifying the assembly process.

[0037] As shown in Figure 5, the backlight module 2 further includes a light-shielding member 25 disposed on the sleeve 24, and a plurality of optical films 26. The optical films 26 are disposed between the diffuser plate 23 and the light-shielding member 25, and each optical film 26 has a through hole 261 to be fitted onto the sleeve 24. The light-shielding member 25 has an annular portion 251 fitted onto the sleeve 24, a top edge portion 252 extending radially outward from the annular portion 251, and a pressing portion 253 extending from the top edge portion 252. The annular portion 251 abuts against the inner circumferential surface of the sleeve 24, and the end edge of the sleeve 24 is covered by the annular portion 251, the top edge portion 252, and the pressing portion 253. The light-shielding member 25 is not only used to limit the optical film 26 and the diffuser plate 23, but also to seal the gap between the sleeve 24, the diffuser plate 23, and the optical film 26, so as to prevent the light from the light-emitting member 222 from leaking out through the gap and causing light leakage.

[0038] Referring to Figures 2 and 3, when the light from the light-emitting element 222 passes through the diffuser plate 23, the printed dots 231 on the light-incident surface of the diffuser plate 23 can reduce the amount of light passing through. Therefore, the diffuser plate 23 is provided with higher density printed dots 231 (i.e., high-density area 233a) corresponding to the locations where there are more light-emitting elements 222, that is, the second lamp area 22b (or the location where more light passes through), and with lower density printed dots 231 (i.e., low-density area 233b) corresponding to the locations where there are fewer light-emitting elements 222, that is, the first lamp area 22a (or the location where less light passes through). In this way, the overall uniformity of the light passing through the diffuser plate 23 can be improved. In addition, as shown in Figure 4, the provision of the light-shielding member 25 can prevent the light from the light-emitting element 222 from leaking through the gap between the optical film 26 and the sleeve 24, or between the diffuser plate 23 and the sleeve 24, thus preventing light leakage. Meanwhile, the pressing portion 253 of the light-shielding member 25 can position and press the optical film 26 and the diffuser plate 23, preventing displacement of the optical film 26 or the diffuser plate 23 and improving the stability of the overall structure after assembly. In this embodiment, the light-shielding member 25 is made of an elastic material (e.g., rubber), which can be directly sleeved and tightened onto the sleeve 24, making assembly convenient.

[0039] Referring to Figure 7, a display panel 3 is provided on the backlight module 2, which is the display device of the present invention. In addition to being supported by a plastic frame 27, the display panel 3 can also be placed on the light shield 25 to prevent the display panel 3 from directly impacting the sleeve 24, thereby protecting the display panel 3.

[0040] In some embodiments, the shape of the light-shielding member 25 is slightly different. As shown in FIG8, the light-shielding member 25 has an annular portion 251 disposed on the sleeve 24, a top edge portion 252 extending radially inward from the annular portion 251 and abutting against the top edge of the sleeve 24, and a pressing portion 253 extending radially outward from the annular portion 251. The annular portion 251 abuts against the outer peripheral surface of the sleeve 24. Alternatively, as shown in FIG9, the light-shielding member 25 is a single-ring structure, fixed to the top edge of the sleeve 24 with adhesive tape. Since the backlight module sleeve 24 is provided with a camera lens 90 or other sensing modules, the annular portion 251 abutting against the inner peripheral surface of the sleeve 24 can prevent the camera lens 90 from directly impacting the sleeve 24, thus achieving a protective effect.

[0041] This invention utilizes the design of different distribution densities of the printed dots 231 on the diffuser plate 23. For example, by using the high-density area 233a to achieve a higher density of printed dots 231 than other areas, it can further suppress areas with excessive brightness near the sleeve 24. Furthermore, by using the dot distribution trend of the low-density area 233b to create a fogging effect on the light-emitting surface near the sleeve 24, it can suppress the halo effect near the sleeve 24 and improve the light emission uniformity of the adjacent sleeve 24, thereby enhancing the optical quality of the backlight module's light-emitting surface. In addition, the light-shielding member 25 provided on the sleeve 24 can prevent light leakage, improve the uniformity of light emission on the overall light-emitting surface of the backlight module 2, and thus improve the quality of the light-emitting surface, effectively reducing the design value of the black Matrix (BM) area of ​​the display panel 3. Moreover, the light-shielding member 25 is made of elastic material, which can be directly pressed for easy assembly, reducing assembly costs, assembly time, mold opening costs, and manufacturing costs.

[0042] In addition, this invention can be applied to direct-drive DMS technology models to accommodate the introduction of technologies such as safe driving, Level 2-5 and autonomous driving. The application of instrument clusters and center information displays (CIDs) is expected to become increasingly widespread.

[0043] However, the above description is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the present invention. All simple equivalent changes and modifications made in accordance with the claims and description of the present invention shall still fall within the scope of the present invention.

[0044]

Symbol Explanation

Claims

1. A backlight module, comprising: Back frame; The light source includes a lamp panel disposed on the back frame and a plurality of light-emitting elements disposed on the lamp panel; A diffuser plate is disposed on the back frame and located on the light-emitting side of the light source; and A sleeve is disposed on the back frame, and the sleeve passes through the lamp plate and the diffuser plate along its axial direction; in, The surface of the diffuser plate has multiple printed dots. The diffuser plate is defined to have a blank area for the sleeve to pass through, and a first area surrounding the blank area. The first area includes at least one high-density area and one low-density area. There are no printed dots in the blank area. The distribution density of the printed dots in the low-density area decreases from the vicinity of the blank area to the direction away from the blank area. The distribution density of the printed dots in the high-density area is greater than the average distribution density of the low-density area.

2. The backlight module as described in claim 1, wherein, The light source has a first lamp area and a second lamp area with light-emitting elements arranged at different intervals. The light-emitting elements in the first lamp area are arranged at equal intervals with a first interval, and the light-emitting elements in the second lamp area are arranged at equal intervals with a second interval. The first interval is greater than the second interval, and the second lamp area corresponds to the high-density area of ​​the diffuser plate.

3. The backlight module as described in claim 1, wherein, The diffuser plate is also defined to have a second zone surrounding the first zone, in which there are no printed dots.

4. The backlight module as described in claim 1, wherein, The back frame includes a base plate and a surrounding portion disposed around the periphery of the base plate. The sleeve is disposed on the base plate and extends unidirectionally away from the base plate.

5. The backlight module as described in claim 1, wherein, The back frame includes a base plate and a surrounding portion disposed around the periphery of the base plate. The sleeve is disposed on the base plate and extends bidirectionally away from the base plate.

6. The backlight module as described in claim 1, wherein, The outer surface of the sleeve has a reflectivity of over 92%.

7. The backlight module as described in claim 1, wherein, The printed dots are disposed on the light-incident surface of the diffuser plate, which faces the lamp plate.

8. The backlight module as described in claim 1, wherein, The sleeve has internal threads.

9. The backlight module as claimed in claim 1 further includes a light-shielding member disposed on the sleeve.

10. The backlight module as claimed in claim 1, further comprising a light-shielding member ring-fitted within the sleeve, wherein, The light-shielding member has an annular portion fitted onto the sleeve, a top edge portion extending radially inward from the annular portion and abutting against the top edge of the sleeve, and a pressing portion extending radially outward from the annular portion, the annular portion abutting against the outer peripheral surface of the sleeve.

11. The backlight module as claimed in claim 1, further comprising a light-shielding member ring-fitted within the sleeve, wherein, The light-shielding member has an annular portion fitted onto the sleeve, a top edge portion extending radially outward from the annular portion, and a pressing portion extending from the top edge portion. The annular portion abuts against the inner circumferential surface of the sleeve, and the end edge of the sleeve is covered by the annular portion, the top edge portion, and the pressing portion.

12. The backlight module as described in claim 9, wherein, The backlight module also includes at least one optical film disposed between the diffuser plate and the light shield, and has perforations corresponding to the sleeve.

13. A display device comprising a backlight module as claimed in any one of claims 1 to 8, and a display panel disposed on the backlight module.

14. A display device comprising a backlight module as claimed in any one of claims 9 to 12, and a display panel disposed on the backlight module, the display panel resting on the light shield.

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