WO2023279224A1

WO2023279224A1 - Backlight module and display apparatus

Info

Publication number: WO2023279224A1
Application number: PCT/CN2021/104428
Authority: WO
Inventors: 张嘉尹; 黄柏菖; 林坤政; 黄建智
Original assignee: 瑞仪光电(苏州)有限公司
Priority date: 2021-07-05
Filing date: 2021-07-05
Publication date: 2023-01-12
Also published as: JP3243169U

Abstract

A backlight module (100) and a display apparatus (1000). The backlight module (100) comprises: a light guide plate (200); a lower light source (400) disposed adjacent to a side edge of the light guide plate (200); a light collecting element (300) disposed adjacent to and above the light guide plate (200), wherein a bottom surface of the light collecting element (300) is provided with a plurality of light collecting structures (350), and the plurality of light collecting structures (350) face the light guide plate (200); and an upper light source (500) disposed adjacent to a light incident side of the light collecting element (300). The display apparatus (1000) comprises a display panel (700) and a backlight module (100). The backlight module (100) and the display apparatus (1000) achieve a narrow-view peep-proof mode by turning on only the lower light source (400), or achieve a wide-view sharing mode by turning on the lower light source (400) and the upper light source (500) simultaneously.

Description

Backlight module and display device

technical field

The invention relates to the field of display technology, in particular to a backlight module and a display device with a switchable viewing angle.

Background technique

With the advancement of science and technology, electronic devices equipped with liquid crystal displays have become an indispensable item in the life of modern people. However, people have different requirements on the viewing angle of the display device in different occasions. For example, when you want to share information with everyone and require multiple people to see the content of the display screen from different angles, the display device is required to have a wide viewing angle, that is, the sharing mode; when processing personal data, only the user needs to see the content of the display screen to When protecting privacy, display products are required to have a narrow viewing angle function, that is, anti-peeping mode.

In order to solve the aforementioned problems, the industry has provided a display device with a dual-light source backlight module. As shown in FIG. The prism sheet 14 , the second light guide plate 15 and the reflective sheet 16 , and the first light source 17 and the second light source 18 respectively adjacent to the light incident sides of the first light guide plate 12 and the second light guide plate 15 .

In the anti-peeping mode, the display device 10 only turns on the second light source 18 below, and the light emitted from the second light source 18 passes through the light guide plate 15 of the second layer, and then passes through the collection and absorption of the reverse prism sheet 14 and the light shielding sheet 13. The light path is limited, and the light emitting angle of the light emitted from the display panel 11 is relatively narrow, so the display screen is only visible to the user himself, and the display device 10 has a narrow viewing angle function. In the sharing mode, the display device 10 turns on the first light source 17 and the second light source 18 at the same time. The light emitted by the light board 12 will reach the display panel 11 at this time with more light, and the light emitting angle is wider, so the content of the display screen can be seen from different angles, and the display device 10 has a wide viewing angle function.

However, the aforementioned viewing angle switching technology uses two light guide plates. In fact, two sets of backlight modules and light-shielding technology are used to achieve the purpose of viewing angle switching. This structure uses more layers of optical plates or optical films, resulting in backlight The overall thickness and cost of the module remain high.

Contents of the invention

The purpose of the present invention is to provide a backlight module technology that integrates the light guide plate and the turning plate. It only needs one set of backlight modules to achieve the function of switching viewing angles, so that the overall thickness of the backlight module can be reduced, and the cost can also be reduced. reduce.

In order to achieve the above object, the present invention provides a backlight module, comprising: a light guide plate; a lower light source, which is adjacent to the side of the light guide plate; a light collecting element, which includes a light incident side and a bottom surface, and the light collecting element is adjacent to Located above the light guide plate, the bottom surface of the light collection element is provided with a plurality of light collection structures, and the plurality of light collection structures face the light guide plate; and an upper light source, which is adjacent to the entrance of the light collection element light side.

As a preferred manner, the light collecting element includes a first side and a second side connected to each other, the first side is parallel to the first direction, the second side is parallel to the second direction, and the first direction is perpendicular In the second direction, the lower light source includes a plurality of light emitting diodes, and the plurality of light emitting diodes of the lower light source are arranged on the side of the light guide plate along the first direction.

As a preferred manner, the light-incident side of the light-collecting element is located on the first side, the upper light source includes a plurality of light-emitting diodes, and the plurality of light-emitting diodes of the upper light source are arranged on the light-collecting element along the first direction. the first side of the element. Alternatively, the light-incident side of the light-collecting element is located on the second side, the upper light source includes a plurality of light-emitting diodes, and the plurality of light-emitting diodes of the upper light source are arranged on the side of the light-collecting element along the second direction. the second side.

As a preferred manner, the light collecting structure is a strip microstructure whose extending direction is substantially parallel to the first direction and perpendicular to the second direction.

As a preferred manner, the light collecting element is a reverse prism sheet, and each light collecting structure has a prism angle, and the tip of the prism angle faces the light guide plate.

As a preferred manner, the bottom surface of the light guide plate is used as a reflective surface, and a plurality of light guide structures are formed on the reflective surface. Each light guide structure has a light-receiving surface and a non-light-receiving surface connected to each other. A second included angle is formed between the light surface and the reflective surface, and the first included angle is an acute angle smaller than the second included angle.

As a preferred manner, uniformly distributed diffusion particles are arranged in the light collecting element. Alternatively, the upper surface of the light collecting element opposite to the bottom surface has a diffusion particle layer.

As a preferred manner, the backlight module further includes a reflection sheet, and the reflection sheet is arranged under the light guide plate.

Another object of the present invention is to provide a display device, which utilizes a backlight module technology integrating a light guide plate and a turning plate, which can achieve the function of switching viewing angles with only one set of backlight modules, making the overall thickness of the display device Thinning can also reduce the cost.

To achieve the above object, the present invention provides a display device, which includes: the above-mentioned backlight module and a display panel adjacent to the top of the backlight module.

Compared with the prior art, the present invention has the following characteristics: the backlight module of the present invention sets light sources respectively on the light guide plate and the light collecting elements above it, so that the light guide plate can be turned on when the lower light source is turned on and the upper light source is turned off. The emitted light is turned and concentrated by the light-collecting element to emit light in the forward direction, realizing the narrow viewing angle anti-peeping mode of the backlight module; The element is turned to emit light in the forward direction, and the light that does not pass through the light guide plate but only passes through the light collecting element is turned to disperse the light, realizing the wide viewing angle sharing mode of the backlight module. The number of optical plates or optical films required by the backlight module of the present invention is small, so that the overall thickness of the backlight module can be reduced, and the cost can also be reduced.

Description of drawings

FIG. 1 is a schematic side view of a display device of a conventional viewing angle switching backlight module.

FIG. 2 is a schematic diagram of a backlight module according to an embodiment of the present application.

FIG. 3 is a schematic diagram of a backlight module according to another embodiment of the present application.

FIG. 4 is a schematic side view of a display device applying the embodiment shown in FIG. 3 .

FIG. 5 is a schematic diagram of a first implementation of a light collecting element in an embodiment of the present application.

FIG. 6 is a schematic diagram of a second implementation of the light collecting element in the embodiment of the present application.

FIG. 7 is a first schematic diagram of light paths in an embodiment of the present application.

FIG. 8 is a second schematic diagram of the light path in the embodiment of the present application.

FIG. 9 is a graph of viewing angle-luminance of the display device applying the embodiment shown in FIG. 3 .

FIG. 10 is a schematic side view of a display device applying the embodiment shown in FIG. 2 .

FIG. 11 is a graph of viewing angle-luminance of the display device applying the embodiment shown in FIG. 2 .

detailed description

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The accompanying drawings are mainly simplified schematic diagrams, which only schematically illustrate the basic structure of the present invention. Therefore, only components related to the present invention are marked in the accompanying drawings, and the displayed components are not in the number, shape, and size ratio of the implementation. After being drawn, the size of the actual implementation is a selective design, and the layout of the components may be more complicated.

The following description of various embodiments refers to the accompanying drawings to illustrate specific embodiments in which the invention may be practiced. The directional terms mentioned in the present invention, such as "upper", "lower", "front", "rear", etc., only refer to the directions in the drawings. Therefore, the directional terms used are used to illustrate and understand the application, but not to limit the application. Also, in the specification, unless it is clearly described to the contrary, the word "comprising" will be understood as meaning including certain elements but not excluding any other elements.

Please refer to FIG. 2 and FIG. 3 , which are schematic diagrams of a backlight module according to an embodiment of the present invention. The backlight module 100 includes: the light guide plate 200; the lower light source 400, which is adjacent to the side 210 of the light guide plate 200; the light collecting element 300, which includes the light incident side 311 (as shown in FIG. 2 ) or 321 (as shown in FIG. 3 As shown) and the bottom surface 340, the light collecting element 300 is adjacent to the top of the light guide plate 200, the bottom surface 340 of the light collecting element 300 is provided with a plurality of light collecting structures 350, and these light collecting structures 350 face the light guide plate 200; and the light source above 500, which is adjacent to the light-incident side 311 (as shown in FIG. 2 ) or 321 (as shown in FIG. 3 ) of the light-collecting element 500 .

The backlight module 100 of the present application is provided with

light sources

400 and 500 respectively on the light guide plate 200 and the light collecting element 300 above it, so that when the lower light source 400 is turned on and the upper light source 500 is turned off, the light emitted through the light guide plate 200 can be collected. The light element 300 turns and concentrates to emit light in the forward direction, realizing the narrow viewing angle anti-peeping mode of the backlight module 100; when both the lower light source 400 and the upper light source 500 are turned on, the light emitted by the lower light source 400 passes through the light guide plate 200 and passes through the light collecting element 300 bends to emit light in the forward direction, while the light from the upper light source 500 is dispersed through the bend of the light collecting element 300 to realize the wide viewing angle sharing mode of the backlight module 100 . Compared with the conventional technology, the number of optical plates or optical films required by the backlight module 100 of the present application is less, and the thickness of the overall structure can be reduced, and the cost can also be reduced.

In practical applications, the backlight module 100 further includes a reflective sheet 600 disposed under the light guide plate 200 .

Please refer to FIG. 4 again, which is a schematic side view of a display device applying the embodiment shown in FIG. 3 . When the aforementioned backlight module 100 is applied to the display device 1000 , the display device 1000 at least includes a display panel 700 and the aforementioned backlight module 100 , and the display panel 700 is disposed adjacent to the top of the backlight module 100 .

In practical applications, the light collecting element 300 includes a first side 310 and a second side 320 connected to each other, the first side 310 is parallel to the first direction D1, the second side 320 is parallel to the second direction D2, and The first direction D1 is perpendicular to the second direction D2. During implementation, the lower light source 400 includes a plurality of light emitting diodes 410 arranged on the side 210 of the light guide plate 200 along the first direction D1 , and the side 210 is essentially the light incident side of the light guide plate 200 .

In practical applications, the light incident side 311 of the light collecting element 300 may be located on the first side 310, the upper light source 500 includes a plurality of light emitting diodes 510, and the plurality of light emitting diodes 510 are arranged on the light collecting element 300 along the first direction D1. on the first side 310 (shown in FIG. 2 ). Or, in practical applications, the light-incident side 321 of the light-collecting element 300 is located on the second side 320, and the upper light source 500 includes a plurality of light-emitting diodes 510, and the plurality of light-emitting diodes 510 are arranged on the light-collecting element along the second direction D2. 300 on the second side 320 (shown in FIG. 3 ).

In practical applications, the bottom surface 340 of the light collecting element 300 is provided with a plurality of light collecting structures 350, the light collecting structures 350 are strip microstructures, the extension direction of the strip microstructures is substantially parallel to the first direction D1, and is parallel to the first direction D1. The two directions D2 are perpendicular. As a preferred embodiment, the light collecting element 300 is an inverse prism sheet, and the light collecting structure 350 has a prism angle 351 , so the light collecting structure 350 is a strip microstructure with a prism angle 351 , and the tip of the prism angle 351 faces the light guide plate 200 .

In practical applications, as shown in FIG. 7 , since the light collecting element 300 requires a specific range of light incident angles, the oblique light generated by the light guide plate 200 can be converted into light in the front view direction through the light collecting element 300 and emitted. Therefore, in order to improve the directivity of the light guide plate 200 , the bottom surface of the light guide plate 200 is used as the reflective surface 230 , and a plurality of light guide structures 240 are formed on the reflective surface 230 . Each light guide structure 240 has a light-receiving surface 241 and a non-light-receiving surface 242 connected to each other. The light-receiving surface 241 faces the light traveling direction of the light source 400 below, and a first included angle α is formed between the light-receiving surface 241 and the reflecting surface 230. , a second included angle β is formed between the non-light-receiving surface 242 and the reflective surface 230, and the first included angle α and the second included angle β are both acute angles, and the first included angle α is smaller than the second included angle β (as shown in FIG. 4 shown). The design of the first included angle α and the second included angle β can change the degree of inclination between the light-receiving surface 241 and the non-light-receiving surface 242, so as to control the direction and concentration of the light emitted from the light-emitting surface of the light guide plate 200 for light collection. The element 300 is further used to effectively guide the light to exit the light at a positive viewing angle.

In the application of this application, if only the lower light source 400 is turned on, the display device 1000 will only provide light through the lower light guide plate 200, and the light guide structure 240 of the light collecting element 300 is used to convert the light into the forward direction to realize the backlight module 100. Narrow viewing angle privacy mode. If both the lower light source 400 and the upper light source 500 are turned on, in addition to the light from the lower light source 400 passing through the light guide plate 200 and then being turned forward by the light collecting element 300, the light from the upper light source 500 will also pass through the light collecting element 300 turns to disperse the light, realizing the wide viewing angle sharing mode of the backlight module 100 .

Furthermore, the light collecting element 300 can use diffusing particles to improve the side viewing angle energy of the sharing mode and provide a wide viewing angle distribution. During implementation, when preparing the light-collecting element 300, uniformly distributed diffusion particles 301 (as shown in FIG. 5 ) are provided in the light-collecting element 300, so that the light passing through the light-collecting element 300 has a better turning and dispersion, so as to Provides a wide viewing angle distribution. Alternatively, a diffusion particle layer 370 (as shown in FIG. 6 ) is provided on the upper surface 360 of the light-collecting element 300 opposite to its bottom surface 340, by means of the diffusion particle layer 370, the light passing through the upper surface 360 of the light-collecting element 300 can be better The turns are dispersed to provide a wide viewing angle distribution.

Hereinafter, the principles of the narrow viewing angle privacy mode and the wide viewing angle sharing mode will be described in more detail. Please refer to FIG. 7 and FIG. 8 to illustrate the light path using the backlight module shown in FIG. 3 . In the backlight module 100, a lower light source 400 and an upper light source 500 are respectively arranged on the light guide plate 200 and the light collecting element 300 above it, and the lower light sources 400 arranged on the light guide plate 200 are arranged along the first direction D1 and arranged on the light collecting element. The upper light sources 500 of 300 are arranged along the second direction D2, and the lower light sources 400 and the upper light sources 500 are arranged perpendicular to each other.

When only the lower light source 400 is turned on, the light L1 emitted by the lower light source 400 will be reflected by the light guide plate 200 with high directivity, and will be turned and concentrated by the light collection structure 350 of the light collection element 300 to be forward light (as shown in FIG. 7 The dotted line pointing up arrow), by only providing light to the display panel 700 by the light guide plate 200, the narrow viewing angle distribution of the light output direction of the backlight module 100 is realized, that is, the upward pointing arrow of the dotted line shown in FIG. 1000 presents a narrow viewing angle anti-peep mode.

When both the lower light source 400 and the upper light source 500 are turned on, in addition to the light L1 of the lower light source 400 passing through the light guide plate 200 and the light-collecting element 300 to turn the forward light, the light L2 of the upper light source 500 is also emitted by the light-collecting element 300 Turning scattered light (as shown in FIG. 8 , the dotted line is directed toward the upper left and the oblique arrows toward the upper right), and the light is provided to the display panel 700 by the light guide plate 200 and the light collecting element 300 at the same time, so that the light output direction of the backlight module 100 can be realized. The distribution of wide viewing angles, that is, in addition to the upward arrows of the dotted lines that emit light in the forward direction in FIG. Moreover, as mentioned above, the light collecting element 300 can make the light L2 have better turning and dispersion by means of diffusing particles, so as to improve the energy of the side viewing angle of the sharing mode, thereby providing a wide viewing angle distribution.

In addition, since the extension directions of the upper light source 500 and the light collecting structure 350 are respectively parallel to the mutually perpendicular second direction D2 and the first direction D1, that is, the upper light source 500 is located on a certain side of the light collecting element 300, therefore, the collecting When viewed along the first direction D1, the optical structure 350 presents a triangle as shown in FIG. 7 , and when viewed along the second direction D2, it presents a plane as shown in FIG. 8 , which is easy to totally reflect the light emitted by the light source 500 above. , so that the ratio of oblique light output away from the direction of the upper light source 500 can be further increased, so the phenomenon of oblique light output can also produce left-right asymmetry, that is, the light intensity represented by the oblique arrow facing the upper right of the dotted line in Figure 8 is greater than that of the dotted line The intensity of light represented by the upward-left slanting arrow makes the wide-angle sharing mode presented by the display device 1000 more suitable for the vehicle-mounted display installed in the center of the vehicle for viewing by the driver's seat or the passenger seat on one side.

As can be seen from FIG. 9 , under the structure of the backlight module 100 shown in FIG. 3 , when only the lower light source 400 is turned on, the luminance of the emitted light is concentrated between -40 degrees and 40 degrees, but when the lower light source 400 and the upper When the light sources 500 are turned on at the same time, the luminance of the emitted light at a viewing angle greater than 40 degrees will be improved. After measurement, the viewing angles of 40 degrees and 45 degrees both have the effect of increasing the viewing angle energy.

Please refer to FIG. 10 again, which is a schematic side view of a display device applying the embodiment shown in FIG. 2 . In the backlight module 100, a lower light source 400 and an upper light source 500 are respectively arranged on the light guide plate 200 and the light collecting element 300 above it, and the lower light sources 400 arranged on the light guide plate 200 are arranged along the first direction D1 and arranged on the light collecting element. The upper light sources 500 of 300 are arranged along the first direction D1, and the lower light sources 400 and the upper light sources 500 are arranged in the same direction.

It can be seen from FIG. 11 that under the structure of the backlight module 100 in FIG. 2 , when only the lower light source 400 is turned on, the luminance of the emitted light is concentrated between -40 degrees and 40 degrees, but when the lower light source 400 and the upper light source 500 When turned on at the same time, the luminance of the light at the viewing angle greater than 40 degrees will also be improved.

Based on the above-mentioned embodiments, it can be seen that by setting light sources separately on the light guide plate and the light-collecting elements above it, the light emitted from the light guide plate can be turned and concentrated into the forward direction when the lower light source is turned on and the upper light source is turned off. Light is emitted to realize the narrow viewing angle anti-peeping mode of the backlight module; when both the lower light source and the upper light source are turned on, not only the light emitted from the light guide plate is turned by the light collecting element to emit light in the forward direction, but also the light that does not pass through the light guide plate but only The light in the light-collecting element is dispersed to realize the wide viewing angle sharing mode of the backlight module. This application does not need to use a light-shielding sheet to achieve the function of switching viewing angles. The number of optical plates or optical films required by the present invention is small, so that the overall thickness of the backlight module can be reduced, and the cost can also be reduced. .

The embodiments disclosed above are only used to illustrate the principles, characteristics and effects of the present invention, and are not intended to limit the scope of the present invention. Next, the above-mentioned embodiment is modified and changed. Any equivalent change and modification accomplished by using the content disclosed in the present invention shall still fall within the scope of the appended claims.

[List of Reference Signs]

(knowledge)

10: Display device

11: Display panel

12: The first layer of light guide plate

13: shading film

14: Inverse prism sheet

15: The second layer of light guide plate

16: reflector

17: First light source

18: Second light source

(this application)

100: Backlight module

200: light guide plate

210: side

230: reflective surface

240: light guide structure

241: Light facing side

242: Non-light facing surface

300: light collecting element

301: Diffuse Particles

310: first side

320: second side

311, 321: light incident side

340: Bottom

350: light collection structure

351: Prism angle

360: upper surface

370: Diffuse Particle Layer

400: Below light source

410, 510: LED

500: top light source

600: reflector

700: display panel

1000: display device

D1: first direction

D2: Second direction

α: first included angle

β: Second included angle.

Claims

A backlight module, comprising:

light guide plate;

a lower light source, which is adjacent to the side of the light guide plate;

A light-collecting element, which includes a light-incident side and a bottom surface, the light-collecting element is adjacent to the top of the light guide plate, and the bottom surface of the light-collecting element is provided with a plurality of light-collecting structures, and the plurality of light-collecting elements the light structure faces the light guide plate; and

The upper light source is adjacent to the light-incident side of the light-collecting element.
The backlight module according to claim 1, wherein the light collecting element comprises a first side and a second side connected to each other, the first side is parallel to the first direction, and the second side Parallel to the second direction, and the first direction is perpendicular to the second direction, the lower light source includes a plurality of light emitting diodes, and the plurality of light emitting diodes of the lower light source are arranged along the first direction on the side of the light guide plate.
The backlight module according to claim 2, wherein the light-incident side of the light-collecting element is located on the first side, the upper light source includes a plurality of light-emitting diodes, and the plurality of light-emitting diodes of the upper light source A plurality of light emitting diodes are arranged along the first direction on the first side of the light collecting element.
The backlight module according to claim 2, wherein the light incident side of the light collecting element is located on the second side, the upper light source includes a plurality of light emitting diodes, and the plurality of light emitting diodes of the upper light source A plurality of light emitting diodes are arranged along the second direction on the second side of the light collecting element.
The backlight module according to claim 2, wherein each of the light collecting structures is a strip microstructure, and its extending direction is parallel to the first direction and perpendicular to the second direction.
The backlight module according to claim 1, wherein the light collecting element is a reverse prism sheet, each of the light collecting structures has a prism angle, and the tip of the prism angle faces the light guide plate.
The backlight module according to claim 1, wherein the bottom surface of the light guide plate is used as a reflective surface, and a plurality of light guide structures are formed on the reflective surface.
The backlight module according to claim 7, wherein each of the light guide structures has a light-receiving surface and a non-light-receiving surface connected to each other, the light-receiving surface faces the light traveling direction of the light source below, and the A first included angle is formed between the light-receiving surface and the reflecting surface, a second included angle is formed between the non-light-facing surface and the reflecting surface, and the first included angle is an acute angle smaller than the second included angle. horn.
The backlight module according to claim 1, wherein uniformly distributed diffusion particles are arranged in the light collecting element.
The backlight module according to claim 1, wherein an upper surface of the light collecting element opposite to the bottom surface has a diffusion particle layer.
The backlight module according to claim 1, further comprising a reflective sheet disposed under the light guide plate.
A display device comprising:

display panel; and

The backlight module according to any one of claims 1 to 11, wherein the display panel is adjacently arranged above the backlight module.