TWM628809U - Backlight module and display apparatus - Google Patents

Abstract

A backlight module including a first light guide plate, a first light source, a diffusor, a second light guide plate, a second light source, a viewing angle control film and a first prism sheet is provided. The first light guide plate has a first light incident surface, and a first bottom surface and a first light emitting surface connected to the first light incident surface and opposite to each other. The diffusor is disposed on one side of the first light emitting surface of the first light guide plate. The second light guide plate is disposed on one side of the first bottom surface of the first light guide plate. The second light guide plate has a second light incident surface, and a second bottom surface and a second light emitting surface connected to the second light incident surface and opposite to each other. The second light emitting surface faces the first bottom surface. The second light source is disposed on one side of the second light incident surface of the second light guide plate. The viewing angle control film is disposed between the first light guide plate and the second light guide plate. The first prism sheet is disposed between the viewing angle control film and the first light guide plate.

Description

Backlight module and display device

The novel creation relates to a backlight module and a display device, and particularly to a backlight module and a display device with two light guide plates.

Generally speaking, in order to allow multiple viewers to watch together, a display device usually has a display effect with a wide viewing angle. However, in some situations or occasions, such as browsing private web pages, confidential information or entering passwords in public, the wide viewing angle display effect is likely to cause the screen to be peeped by others, resulting in leakage of confidential information. In order to achieve privacy protection, the general practice is to place a Light Control Film (LCF) in front of the display panel to filter out light from a large angle. In addition, for the convenience of switching of the anti-peep function, an electronically controlled diffusion film can be arranged above the light control film. When there is no need for privacy protection, the electronically controlled diffuser film is controlled in a scattering state, so that the small-angle light from the light control film can be scattered to a larger viewing angle range through the electronically controlled diffuser film. However, such an approach will cause the light energy of the light source to not be effectively utilized. Therefore, how to develop a display device with extremely convenient viewing angle switching and better light energy utilization rate of the backlight module has become an important issue for related manufacturers.

The novel creation provides a backlight module with better utilization of light energy.

The novel creation provides a display device with better utilization of light energy in both the sharing mode and the anti-privacy mode.

Other purposes and advantages of the novel creation can be further understood from the technical features disclosed in the novel creation.

To achieve one or part or all of the above purposes or other purposes, an embodiment of the present invention provides a backlight module. The backlight module includes a first light guide plate, a first light source, a diffusion sheet, a second light guide plate, a second light source, a viewing angle control sheet and a first iris sheet. The first light guide plate has a first light incident surface, a first bottom surface and a first light emitting surface which are connected to the first light incident surface and are opposite to each other. The first light source is arranged on one side of the first light incident surface of the first light guide plate. The diffusing sheet is arranged on one side of the first light emitting surface of the first light guide plate. The second light guide plate is arranged on one side of the first bottom surface of the first light guide plate. The second light guide plate has a second light incident surface, a second bottom surface and a second light emitting surface which are connected to the second light incident surface and are opposite to each other. The second light emitting surface faces the first bottom surface. The second light source is arranged on one side of the second light incident surface of the second light guide plate. The viewing angle control sheet is arranged between the first light guide plate and the second light guide plate. The first diaphanous sheet is arranged between the viewing angle control sheet and the first light guide plate.

In an embodiment of the present invention, the range of the haze value of the diffuser sheet of the backlight module is greater than or equal to 10% and less than or equal to 95%.

In an embodiment of the present invention, the range of the haze value of the diffuser sheet of the backlight module is greater than or equal to 25% and less than or equal to 75%.

In an embodiment of the present invention, the first light incident surface of the above-mentioned backlight module is perpendicular to the second light incident surface.

In an embodiment of the present invention, the above-mentioned first wafer of the backlight module has a first substrate and a plurality of first wafer structures disposed on the first substrate. The included angle between the extension direction of the orthographic projection of each first ridge structure on the first bottom surface and the first light incident surface is greater than or equal to 60 degrees and less than or equal to 120 degrees.

In an embodiment of the present invention, the above-mentioned backlight module further includes a second iris sheet disposed between the viewing angle control sheet and the second light guide plate. The second wafer has a second substrate and a plurality of second wafer structures disposed on the second substrate. The included angle between the extension direction of the orthographic projection of each of the second hexagonal structures on the first substrate and the extension direction of the orthographic projection of each of the first hexagonal structures on the first substrate is less than or equal to 30 degrees.

In an embodiment of the present invention, the above-mentioned backlight module further includes a third plate, which is disposed on one side of the first light emitting surface of the first light guide plate. The third wafer has a third substrate and a plurality of third wafer structures disposed on the third substrate. The included angle between the extension direction of the orthographic projection of each third light-emitting surface on the first light-emitting surface and the first light-incident surface is less than or equal to 30 degrees.

In an embodiment of the present invention, the first light guide plate of the above-mentioned backlight module further has a plurality of first optical microstructures disposed on the first bottom surface. Each of the first optical microstructures has a first light-facing surface facing the first light source. The first included angle between the first light-upward surface and the first bottom surface is greater than or equal to 3 degrees and less than or equal to 60 degrees. The second light guide plate also has a plurality of second optical microstructures disposed on the second bottom surface. Each of the second optical microstructures has a second light-facing surface facing the second light source. The second included angle between the second light-upward surface and the second bottom surface is greater than or equal to 3 degrees and less than or equal to 18 degrees.

In an embodiment of the present invention, the above-mentioned backlight module further includes a third light source disposed on one side of the third light incident surface of the first light guide plate. The third light incident surface is connected to the first light exit surface and the first bottom surface, and is disposed opposite to the first light incident surface. Each of the first optical microstructures also has a third light-facing surface facing the third light source. The third included angle between the third light-facing surface and the first bottom surface is greater than or equal to 3 degrees and less than or equal to 60 degrees.

In an embodiment of the present invention, the first light guide plate of the above-mentioned backlight module further has a plurality of first columnar structures disposed on the first light emitting surface. The extending direction of each of the first columnar structures is perpendicular to the first light incident surface.

In an embodiment of the present invention, each first columnar structure of the above-mentioned backlight module has a height along the normal direction of the first light emitting surface, and is perpendicular to the extending direction of each first columnar structure And a direction parallel to the first light emitting surface has a width. The ratio of the height to the width of each of the first columnar structures is greater than or equal to 0.1.

In an embodiment of the present invention, the second light guide plate of the above-mentioned backlight module further has a plurality of second columnar structures disposed on the second light emitting surface. The extending direction of each of the second columnar structures is perpendicular to the second light incident surface.

In an embodiment of the present invention, each second columnar structure of the above-mentioned backlight module has a height along the normal direction of the second light emitting surface, and is perpendicular to the extending direction of each second columnar structure and a direction parallel to the second light emitting surface has a width. The ratio of the height to the width of each of the second columnar structures is greater than or equal to 0.1.

In an embodiment of the present invention, the above-mentioned backlight module further includes an electronically controlled diffusion film, which is disposed on one side of the first light emitting surface of the first light guide plate and is suitable for switching between the scattering state and the transparent state. operate.

In an embodiment of the present invention, the above-mentioned diffusion sheet of the backlight module is located between the first light guide plate and the electronically controlled diffusion film.

In an embodiment of the present invention, the above-mentioned backlight module further includes an electronically controlled viewing angle switcher, which is disposed on one side of the first light emitting surface of the first light guide plate, and includes a liquid crystal layer and is disposed on opposite sides of the liquid crystal layer. at least two electrode layers or at least one electrode layer disposed on one side of the liquid crystal layer.

In order to achieve one or part or all of the above purposes or other purposes, an embodiment of the present invention provides a display device. The display device includes a backlight module and a display panel. The backlight module includes a first light guide plate, a first light source, a diffusion sheet, a second light guide plate, a second light source, a viewing angle control sheet and a first iris sheet. The first light guide plate has a first light incident surface, a first bottom surface and a first light emitting surface which are connected to the first light incident surface and are opposite to each other. The first light source is arranged on one side of the first light incident surface of the first light guide plate. The diffusing sheet is arranged on one side of the first light emitting surface of the first light guide plate. The second light guide plate is arranged on one side of the first bottom surface of the first light guide plate. The second light guide plate has a second light incident surface, a second bottom surface and a second light emitting surface which are connected to the second light incident surface and are opposite to each other. The second light emitting surface faces the first bottom surface. The second light source is arranged on one side of the second light incident surface of the second light guide plate. The viewing angle control sheet is arranged between the first light guide plate and the second light guide plate. The first diaphanous sheet is arranged between the viewing angle control sheet and the first light guide plate. The display panel is arranged on one side of the first light emitting surface of the first light guide plate, and overlaps the first light emitting surface and the second light emitting surface.

In an embodiment of the present invention, the above-mentioned backlight module of the display device further includes an electronically controlled diffusion film, which is disposed between the first light guide plate and the display panel and is suitable for switching between the scattering state and the transparent state. operate.

In an embodiment of the present invention, the above-mentioned backlight module of the display device further includes an electronically controlled viewing angle switcher, disposed between the first light guide plate and the display panel, including a liquid crystal layer and disposed on opposite sides of the liquid crystal layer at least two electrode layers or at least one electrode layer disposed on one side of the liquid crystal layer.

Based on the above, in the backlight module and the display device according to an embodiment of the present invention, a first iris sheet is provided between the first light guide plate and the second light guide plate which are arranged to overlap with each other. When the display device operates in the sharing mode, the first iris can reflect part of the light emitted from the first bottom surface of the first light guide plate back to the first light guide plate, so as to increase the utilization rate of light energy of the first light source. When the display device operates in the privacy-prevention mode, the first iris can also increase the light concentration of the light from the second light guide plate, so as to improve the forward brightness of the display device. In addition, arranging the viewing angle control sheet between the two light guide plates can effectively reduce the risk that the light emitted by the first light source of the display device is absorbed by the viewing angle control sheet when the display device operates in the sharing mode, which helps to improve the backlight module's performance. Light energy utilization.

In order to make the above-mentioned features and advantages of the novel creation more obvious and easy to understand, the following embodiments are given and described in detail with the accompanying drawings as follows.

The aforementioned and other technical contents, features and effects of the novel creation will be clearly presented in the following detailed description of a preferred embodiment with reference to the drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or rear, etc., are only for referring to the directions of the attached drawings. Therefore, the directional terms used are intended to illustrate and not to limit the present invention.

1A and 1B are schematic side views of the display device according to the first embodiment of the present invention in different directions, respectively. 2 , 3 and 5 are schematic top views of some components of the display device of FIG. 1A , respectively. FIG. 4 is a schematic top view of another modified embodiment of some components of the display device of FIG. 1A . FIG. 6A is a schematic diagram illustrating the distribution of the brightness of the light emitted by different light sources to the viewing angle when the display device according to the first embodiment of the present invention operates in a sharing mode. FIG. 6B is a schematic diagram showing the distribution of total luminance versus viewing angle of the display device operating in the sharing mode according to the first embodiment of the present invention. FIG. 7 is a distribution curve diagram of normalized luminance versus viewing angle of the display device operating in the sharing mode and the privacy protection mode according to the first embodiment of the present invention.

Please refer to FIG. 1A and FIG. 1B , the display device 10 includes a backlight module 100 and a display panel 200 which are arranged in an overlapping manner. The backlight module 100 includes a first light guide plate 110 and a second light guide plate 120 arranged in an overlapping manner, wherein the first light guide plate 110 is located between the display panel 200 and the second light guide plate 120 . The first light guide plate 110 has a first light incident surface 110is1, a first light exit surface 110es and a first bottom surface 110bs which are connected to the first light incident surface 110is1 and are opposite to each other. The display panel 200 is disposed on one side of the first light emitting surface 110es of the first light guide plate 110 and overlaps the first light emitting surface 110es. The second light guide plate 120 is disposed on one side of the first bottom surface 110bs of the first light guide plate 110 . The display panel 200 is, for example, a liquid crystal display panel, or other non-self-luminous display panels.

On the other hand, the second light guide plate 120 has a second light incident surface 120is, a second light exit surface 120es and a second bottom surface 120bs which are connected to the second light incident surface 120is and are opposite to each other. The second light emitting surface 120es of the second light guide plate 120 faces the first bottom surface 110bs of the first light guide plate 110 . The display panel 200 overlaps the second light emitting surface 120es. It should be noted that, in this embodiment, the first light guide plate 110 may further have a third light incident surface 110is2 connected to the first light exit surface 110es and the first bottom surface 110bs and disposed opposite to the first light incident surface 110is1, but not This is the limit.

A first light source LS1 is provided on one side of the first light incident surface 110is1 of the first light guide plate 110 . A second light source LS3 is provided on one side of the second light incident surface 120is of the second light guide plate 120 . A third light source LS2 is provided on one side of the third light incident surface 110is2 of the first light guide plate 110 . For example, the first light incident surface 110is1 and the third light incident surface 110is2 of the first light guide plate 110 may be respectively perpendicular to the second light incident surface 120is of the second light guide plate 120 (as shown in FIG. 2 ), but not This is limited. The first light source LS1 , the third light source LS2 and the second light source LS3 are, for example, light bars or cold cathode tubes composed of a plurality of light emitting elements (eg, light emitting diodes) and circuit boards, but not limited thereto. In order to increase the utilization rate of light energy, a side of the second bottom surface 120bs of the second light guide plate 120 may further be provided with a reflection sheet 160, such as a silver reflection sheet, a white reflection sheet, or other suitable reflection sheets.

Further, the backlight module 100 further includes a viewing angle control sheet 130 , a first iris sheet 140 and a diffusion sheet 170 . The viewing angle control sheet 130 is disposed between the first light guide plate 110 and the second light guide plate 120 . The first iris sheet 140 is disposed between the first light guide plate 110 and the viewing angle control sheet 130 . The diffusion sheet 170 is disposed on one side of the first light emitting surface 110es of the first light guide plate 110 and is located between the first light guide plate 110 and the display panel 200 . The viewing angle control sheet 130 is, for example, 3M's Louver film, Toray's PICASUS VT, or a polarized viewing angle control element. In this embodiment, the viewing angle control sheet 130 can define the viewing angle control direction VD of the display device 10 , and the viewing angle control direction VD is, for example, parallel to the direction X in FIG. 1A . For example, the viewing angle control sheet 130 may be provided with a plurality of light-shielding walls 135, and the light-shielding walls 135 are arranged at intervals along the direction X and extend in the direction Y, wherein the light-shielding walls 135 are used to at least partially reflect or absorb light, while the opposite Light can pass between the two adjacent light-shielding walls 135 .

The first wafer 140 has a first substrate 141 and a plurality of first wafer structures 142 . The first ridge structures 142 are arranged along the direction Y on the side surface of the first substrate 141 facing the first light guide plate 110 , and extend in the direction X. As shown in FIG. In this embodiment, the extension direction of the orthographic projection of the first ridge structure 142 on the first bottom surface 110bs of the first light guide plate 110 is the same as that of the first light incident surface 110is1 (or the third light incident surface of the first light guide plate 110 ). 110is2), the included angle A1 can be 90 degrees (as shown in Figure 3). However, the present invention is not limited to this. In other not-shown embodiments, the included angle A1 may also be any angle other than 90 degrees within a range of greater than or equal to 60 degrees and less than or equal to 120 degrees.

In this embodiment, the first light source LS1 and the third light source LS2 are adapted to emit light respectively toward the first light guide plate 110 , wherein part of the light LB1 and the light LB2 are transmitted from the first light emitting surface 110es through the lateral direction of the first light guide plate 110 . The first light guide plate 110 is emitted and transmitted to the display panel 200 . Since another part of the light (for example, the light LB1 ″) will be emitted through the first bottom surface 110bs of the first light guide plate 110 during the lateral transmission process in the first light guide plate 110 and transmitted to the viewing angle control sheet 130 , the viewing angle control sheet 130 The shading wall 135 reflects or absorbs the light, causing the loss of light energy or the formation of stray light. Through the arrangement of the first iris sheet 140, such unintended light rays (eg, light LB1") can be reflected back to the first light guide plate 110 , thereby increasing the light energy utilization rate of the light source.

In addition, after the light LB3 emitted by the second light source LS3 is transmitted and exited in the lateral direction of the second light guide plate 120 , the light path thereof will be deflected toward the front view direction (eg, the direction Z) after passing through the first iris sheet 140 . In other words, the disposition of the first iris sheet 140 can also be used to increase the light collecting property of the light LB3 after exiting from the second light guide plate 120 , so as to improve the forward luminance of the display device 10 .

The backlight module 100 may also optionally include a second iris sheet 150 disposed between the viewing angle control sheet 130 and the second light guide plate 120 . Similar to the first wafer 140 , the second wafer 150 has a second substrate 151 and a plurality of second wafer structures 152 . The second ridge structures 152 are arranged along the direction Y on the side surface of the second substrate 151 facing the first light guide plate 110 , and extend in the direction X. As shown in FIG. That is, the extending direction of the orthographic projection of the second ridge structure 152 on the first substrate 141 is substantially parallel to the extending direction of the orthographic projection of the first ridge structure 142 on the first substrate 141 . In simple terms, the extending direction of the second insulating structure 152 of the second insulating sheet 150 is substantially parallel to the extending direction of the first insulating portion 142 of the first insulating sheet 140 . However, the novel creation is not limited to this. In another embodiment, the included angle A2 between the extending direction of the second apron structure 152A of the second apron sheet 150A and the extending direction of the first apron structure 142 of the first wafer 140 may also be greater than 0 degrees and less than is equal to 30 degrees (as shown in Figure 4).

The light LB3 of the twice refracted part of the first hexagonal structure 142 and the second hexagonal structure 152 can be transmitted to the first light guide plate 110 in a light path closer to the front view direction. In addition to reducing the proportion of the light LB3 absorbed by the viewing angle control sheet 130 after exiting the second light guide plate 120 (that is, increasing the light energy utilization rate of the second light source LS3 ), it can further increase the concentration of light emitted by the second light guide plate 120 .

In this embodiment, the display device 10 is suitable for operating in a sharing mode with a larger viewing angle range or a privacy mode with a smaller viewing angle range. It should be noted that, when the display device 10 operates in the privacy-proof mode, only the second light source LS3 provides the illumination light required for the privacy-proof display. When the display device 10 operates in the sharing mode, the first light source LS1 , the third light source LS2 and the second light source LS3 provide the illumination light required for wide viewing angle display.

In order to deflect the light path emitted by the first light source LS1 or the third light source LS2 toward the front view direction, a plurality of first optical microstructures MS1 may be further provided on the first bottom surface 110bs of the first light guide plate 110 . In this embodiment, the first optical microstructure MS1 has a first light-facing surface RS1 facing the first light source LS1 and a third light-facing surface RS2 facing the third light source LS2, wherein the first light-facing surface RS1 is suitable for The light LB1 transmitted by the first light source LS1 and transmitted in the first light guide plate 110 is reflected so that it can exit the first light guide plate 110 in a more positive light path, and the third light-facing surface RS2 is suitable for the light from the third light source LS2. And the light LB2 transmitted in the first light guide plate 110 is reflected, so that it can exit the first light guide plate 110 in a more positive light path (as shown in FIG. 1A ).

Similarly, in order to deflect the light path emitted by the second light source LS3 toward the front view direction, a plurality of second optical microstructures MS2 may be further provided on the second bottom surface 120bs of the second light guide plate 120 . In this embodiment, the second optical microstructure MS2 has a second light-facing surface RS3 facing the second light source LS3 , and the second light-facing surface RS3 is suitable for connecting the light from the second light source LS3 to the second light guide plate 120 The transmitted light LB3 is reflected so that it can exit the second light guide plate 120 in a more positive light path (as shown in FIG. 1B ).

The first included angle θ1 between the first light-facing surface RS1 and the first bottom surface 110bs of the first optical microstructure MS1 and the third included angle θ2 between the third light-facing surface RS2 and the third bottom surface 110bs can be selectively the same, The first included angle θ1 and the third included angle θ2 are both greater than or equal to 3 degrees and less than or equal to 60 degrees. On the other hand, the second angle θ3 between the second light-facing surface RS3 of the second optical microstructure MS2 and the second bottom surface 120bs is greater than or equal to 3 degrees and less than or equal to 18 degrees.

For example, in this embodiment, the first included angle θ1 and the third included angle θ2 may be greater than or equal to 3 degrees and less than or equal to 30 degrees. Accordingly, the light LB1 from the first light source LS1 is reflected by the first light-facing surface RS1 of the first optical microstructure MS1 to form a light energy distribution in the right-side viewing angle range (as shown by the curve C1a in FIG. 6A ), The light LB2 from the third light source LS2 forms a light energy distribution in the left-side viewing angle range after being reflected by the third light-facing surface RS2 of the first optical microstructure MS1 (as shown by the curve C2a in FIG. The light LB3 of the two light sources LS3 is reflected by the second light-facing surface RS3 of the second optical microstructure MS2 to form a light energy distribution in the front viewing angle range (as shown by the curve C3a in FIG. 6A ).

On the other hand, in order to increase the light collecting property of the first light guide plate 110 along the direction Y, a plurality of first columnar structures 115 may be further disposed on the light exit surface 110es of the first light guide plate 110 . The first columnar structures 115 are arranged along the direction Y and extend in the direction X. As shown in FIG. More specifically, the extending direction of the first columnar structure 115 may be perpendicular to the first light incident surface 110is1 and the third light incident surface 110is2 of the first light guide plate 110 (as shown in FIG. 2 ). The first columnar structure 115 has a height h1 along the normal direction of the first light emitting surface 110es (eg, the direction Z), and is perpendicular to the extending direction of the first columnar structure 115 and parallel to the first light emitting surface 110es (eg direction Y) has width w1. Preferably, the ratio of the height h1 to the width w1 of the first columnar structure 115 is greater than or equal to 0.1.

Similarly, in order to increase the light collecting property of the second light guide plate 120 along the direction X, a plurality of second columnar structures 125 may also be disposed on the second light emitting surface 120es of the second light guide plate 120 . The second columnar structures 125 are arranged along the direction X and extend in the direction Y. As shown in FIG. More specifically, the extending direction of the second columnar structures 125 may be perpendicular to the second light incident surface 120is of the second light guide plate 120 (as shown in FIG. 2 ). The second columnar structure 125 has a height h2 along the normal direction of the second light exit surface 120es (eg, the direction Z), and is along a direction perpendicular to the extending direction of the second columnar structure 125 and parallel to the second light exit surface 120es (eg direction X) has width w2. Preferably, the ratio of the height h2 to the width w2 of the second columnar structure 125 is greater than or equal to 0.1.

Further, the backlight module 100 can be optionally provided with a third fin 180 and an electronically controlled diffusion film 190 on one side of the first light emitting surface 110es of the first light guide plate 110 , wherein the third fin 180 The diffusion sheet 170 is located between the electronically controlled diffusion film 190 and the first light guide plate 110 , and the diffusion sheet 170 is located between the first light guide plate 110 and the electronically controlled diffusion film 190 . The third wafer 180 has a third substrate 181 and a plurality of third wafer structures 182 . The third ridge structures 182 are arranged along the direction X on a side surface of the third substrate 181 away from the first light guide plate 110 and extend in the direction Y. Preferably, the extension direction of the orthographic projection of the third ridge structure 182 on the first light exit surface 110es of the first light guide plate 110 is the same as that of the first light incident surface 110is1 (or the third light incident surface 110is2 of the first light guide plate 110 ). ) is greater than 0 degrees and less than or equal to 30 degrees. For example, in this embodiment, the extension direction of the orthographic projection of the third ridge structure 182 on the first light exit surface 110es of the first light guide plate 110 can be selectively parallel to the first entrance of the first light guide plate 110 . The light surface 110is1 and the third light incident surface 110is2 (as shown in FIG. 5 ).

In the present embodiment, the electronically controlled diffusion film 190 is adapted to switch operation between the scattering state and the transparent state. For example, when the display device 10 operates in the sharing mode, the scattering state of the electronically controlled diffusion film 190 can be used to expand the viewing angle distribution range of the light LB1 , the light LB2 and the light LB3 , so that the light from different light sources can be emitted in the first The overall light pattern distribution after a light guide plate 110 is more uniform (as shown in FIG. 6B ). On the contrary, when the display device 10 operates in the privacy protection mode, the transparent state of the electronically controlled diffusion film 190 is used, so that the light LB3 from the second light source LS3 maintains the existing light distribution after passing through the electronically controlled diffusion film 190 .

The electronically controlled diffusion film 190 is, for example, a polymer dispersed liquid crystal (PDLC) film, a polymer network liquid crystal (PNLC) film, or a liquid crystal lens (LC Lens).

As shown in FIG. 7 , when the display device 10 of the present embodiment operates in the sharing mode, three light sources are used to emit light at the same time and the configuration relationship of the above-mentioned film layer structures is used to disperse the light energy distribution of these light sources in different viewing angle ranges. inside, and through the scattering state of the electronically controlled diffusion film 190, the overall light-emitting brightness distribution is more uniform and the viewing angle range is wider. When the display device 10 is operated in the privacy protection mode, only the second light source LS3 emits light, and the configuration relationship of the above-mentioned film layer structures is used to make the light patterns of the emitted light concentrated within the range of the front viewing angle.

FIG. 8A is a schematic diagram illustrating the distribution of light-emitting luminances of different light sources versus viewing angles when the display device according to another modification of FIG. 1A operates in a sharing mode. FIG. 8B is a schematic diagram illustrating the distribution of total luminance versus viewing angle of the display device operating in the sharing mode according to another variant embodiment of FIG. 1A . Different from the light energy distribution in FIG. 6A , when the first included angle θ1 between the first light-facing surface RS1 and the first bottom surface 110bs of the first optical microstructure MS1 on the first light guide plate 110 and the third light-facing surface RS2 and the first When the third angle θ2 of the bottom surface 110bs is greater than 30 degrees and less than or equal to 60 degrees, after the light LB1 from the first light source LS1 exits the first light guide plate 110, the light energy distribution of the light energy distribution is still closer to the right viewing angle but closer to the front viewing angle ( as shown by curve C1b in Figure 8A). Similarly, after the light LB2 from the third light source LS2 exits the first light guide plate 110 , its light energy distribution is still closer to the frontal viewing angle (as shown by the curve C2 b in FIG. 8A ), although it is still biased towards the left viewing angle. That is to say, in this modified embodiment, the light emitting distribution of the first light source LS1 and the third light source LS2 on the first light emitting surface 110es of the first light guide plate 110 is closer to that of the second light source LS3 in the first light guide plate 110 than in FIG. 6A . The light emitting distribution of the first light emitting surface 110es of the light guide plate 110 (curve C3b in FIG. 8A ).

FIG. 8B shows the superimposed light patterns formed by the light of the above-mentioned light sources after being scattered by the electronically controlled diffusion film 190 . Compared with FIG. 6B , in the modified embodiment, the display device may have a higher luminance output in the front viewing angle range.

Since the degree of dispersion of the light distributions of the three light sources of the display device 10 (as shown in FIG. 6A and FIG. 8A ) can be changed by adjusting the optical microstructure of the light guide plate, the selection of the diffuser 170 can be more flexible. For example, the haze value of the diffusing sheet 170 ranges from 10% to 95%. Preferably, the haze value of the diffusing sheet 170 ranges from 25% to 75%.

Hereinafter, other embodiments will be listed to describe the present disclosure in detail, wherein the same components will be marked with the same symbols, and the description of the same technical content will be omitted.

9A and 9B are schematic side views of the backlight module of the second embodiment of the present invention in different directions, respectively. Referring to FIGS. 9A and 9B , the difference between the backlight module 100A of this embodiment and the backlight module 100 of FIGS. 1A and 1B is that the backlight module 100A is not provided with the third plate 180 and the third light source of FIG. 1A . LS2.

Different from the first optical microstructure MS1 of the first light guide plate 110 in FIG. 1 having the first light-facing surface RS1 and the third light-facing surface RS2 arranged symmetrically, the first optical microstructure of the first light guide plate 110A of this embodiment MS1-A has a first light-facing surface RS1 facing the first light source LS1 and a backlight surface BS farther away from the light source LS1, and the first light-facing surface RS1 and the backlight surface BS are asymmetrically arranged. Specifically, the first angle θ1 ′ between the first light-facing surface RS1 and the first bottom surface 110bs of the first optical microstructure MS1-A is different from the fourth angle θ4 between the backlight surface BS and the first bottom surface 110bs of the first optical microstructure MS1-A . Accordingly, the backlight module 100A can meet the lighting requirements of the asymmetric light type.

10A and 10B are schematic side views of the backlight module of the third embodiment of the present invention in different directions, respectively. Referring to FIGS. 10A and 10B , the difference between the backlight module 100B of this embodiment and the backlight module 100 of FIGS. 1A and 1B is that the backlight module 100B may not be provided with the second fin 150 and the third rib of FIG. 1A Lens 180.

Since the functions of the components of the backlight module 100B are similar to those of the backlight module 100 of FIG. 1A , please refer to the relevant paragraphs of the foregoing embodiments for detailed description.

FIG. 11A and FIG. 11B are schematic side views of the display device of the fourth embodiment of the present invention in different directions, respectively. FIG. 12 is a schematic cross-sectional view of the electronically controlled viewing angle switch of FIG. 11A . FIG. 13 is a schematic diagram illustrating the distribution of brightness versus viewing angle of the display device of FIG. 11A under different privacy protection modes. Referring to FIGS. 11A to 12 , the difference between the display device 20 of this embodiment and the display device 10 of FIG. 1A is that the backlight module 100C of this embodiment replaces the backlight module of FIG. 1A with an electronically controlled viewing angle switch 195 Electronically controlled diffusion membrane 190 of 100 .

In this embodiment, the electronically controlled viewing angle switch 195 may include a liquid crystal layer LCL, an electrode layer EL1, an electrode layer EL2, a substrate SUB1, a substrate SUB2, an alignment film AL1, an alignment film AL2, a polarizer POL1, and a polarizer POL2. The liquid crystal layer LCL is disposed between the substrate SUB1 and the substrate SUB2. The electrode layer EL1 is disposed between the liquid crystal layer LCL and the substrate SUB1. The electrode layer EL2 is disposed between the liquid crystal layer LCL and the substrate SUB2. The alignment layer AL1 is disposed between the liquid crystal layer LCL and the electrode layer EL1. The alignment layer AL2 is disposed between the liquid crystal layer LCL and the electrode layer EL2. The polarizer POL1 and the polarizer POL2 are respectively disposed on opposite sides of the substrate SUB1 and the substrate SUB2 away from the liquid crystal layer LCL.

Specifically, the viewing angle control direction VD of the display device 20 can be defined by the absorption axis axis of the polarizer POL2 that is closer to the display panel 200 . That is, in this embodiment, the axial direction of the absorption axis of the polarizer POL2 is parallel to the direction X. As shown in FIG.

On the other hand, the alignment film is used for aligning a plurality of liquid crystal molecules (not shown) of the liquid crystal layer LCL so that the optical axes thereof are oriented in a predetermined direction. In this embodiment, the alignment directions of the two alignment films AL1 and AL2 may intersect with each other, for example, the angle between the two alignment directions may be in the range of 90 degrees to 270 degrees, and the liquid crystal layer LCL may include twisted nematic liquid crystal ( Twisted Nematic Liquid Crystal, TN-LC). That is, the electronically controlled viewing angle switch 195 of this embodiment may include a twisted nematic liquid crystal cell (TN-LC cell) or a super twisted nematic liquid crystal cell (STN-LC cell). However, the present invention is not limited to this. According to other embodiments, the operation mode of the liquid crystal cell of the electronically controlled viewing angle switcher can also be an electrically controlled birefringence (ECB) mode, an optically compensated bend (OCB) mode ) mode, in-plane switching (IPS) mode, or vertical alignment / multi domain vertical alignment (VA / MVA) mode.

Further, when the electrode layer EL1 and the electrode layer EL2 are enabled to have a potential difference between the two electrode layers, the potential difference can form an electric field between the two electrode layers to drive the liquid crystal molecules of the liquid crystal layer LCL to rotate to change The overall phase retardation is used to change the polarization state of the light passing through the liquid crystal layer LCL. In this embodiment, the electrode layer EL1 and the electrode layer EL2 are, for example, light-transmitting electrodes, and the materials of the light-transmitting electrodes include indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, or other suitable oxides, very thin metals, metal mesh or wire grids, carbon nanotubes, Ag nano-wires, graphene, or a stack of at least two of the above Floor. It should be noted that, in the novel creation, the electrode layers of the electronically controlled viewing angle switcher can be at least two electrode layers disposed on opposite sides of the liquid crystal layer according to the operation modes of different liquid crystal cells, or disposed on the liquid crystal layer. At least one electrode layer on one side of the layer.

In this embodiment, the display device 20 can be further provided with different degrees of privacy protection through the setting of the electronically controlled viewing angle switch 195 . Please also refer to FIG. 13 , for example, when the display device 20 performs anti-peep display (ie, the second light source LS3 is enabled to emit light), if the electronically controlled viewing angle switch 195 is inactive, the display device 20 operates in the first anti-peep display. The peep-proof mode has a first viewing angle range; if the electronically controlled viewing angle switch 195 is active, the display device 20 operates in the second privacy mode and has a second viewing angle range, wherein the second viewing angle range is smaller than the first viewing angle range. Viewing angle range.

To sum up, in the backlight module and the display device according to an embodiment of the present invention, the first light guide plate is provided between the first light guide plate and the second light guide plate which are arranged to overlap each other. When the display device operates in the sharing mode, the first iris can reflect part of the light emitted from the first bottom surface of the first light guide plate back to the first light guide plate, so as to increase the utilization rate of light energy of the first light source. When the display device operates in the privacy-prevention mode, the first iris can also increase the light concentration of the light from the second light guide plate, so as to improve the forward brightness of the display device. In addition, arranging the viewing angle control sheet between the two light guide plates can effectively reduce the risk that the light emitted by the first light source of the display device is absorbed by the viewing angle control sheet when the display device operates in the sharing mode, which helps to improve the backlight module's performance. Light energy utilization.

However, the above is only the preferred embodiment of the new creation, and should not limit the scope of the implementation of the new creation, that is, the simple equivalence made according to the patent scope of the new creation and the content of the new creation. Changes and modifications are still within the scope of the present invention patent. In addition, any embodiment of the novel creation or the scope of the patent application does not need to achieve all the purposes, advantages or features disclosed in the novel creation. In addition, the abstract part and the title are only used to assist the search of patent documents, and are not used to limit the scope of rights of the new creation. In addition, terms such as "first" and "second" mentioned in this specification or the scope of the patent application are only used to name the elements or to distinguish different embodiments or scopes, and are not used to limit the number of elements. upper or lower limit.

10, 20: Display device 100, 100A, 100B, 100C: Backlight module 110, 110A: the first light guide plate 120: Second light guide plate 110bs: first bottom surface 120bs: Second Bottom Side 110es: The first light-emitting surface 120es: The second light-emitting surface 110is1: The first light incident surface 110is2: The third light incident surface 120is: the second light incident surface 115: The first columnar structure 125: Second column structure 130: Perspective Control Film 135: Shading Wall 140: The First Pills 150, 150A: The second film 180: The Third Pills 141: The first substrate 151: Second substrate 181: Third substrate 142: The first zodiac structure 152, 152A: The second structure 182: The third structure 160: Reflector 170: Diffuser 190: Electronically Controlled Diffusion Film 195: Electronically controlled viewing angle switcher 200: Display panel A1, A2: included angle AL1, AL2: Alignment layer BS: Backlight side EL1, EL2: Electrode layer h1, h2: height LB1, LB1", LB2, LB3: Light LCL: liquid crystal layer LS1: The first light source LS2: The third light source LS3: Second light source MS1, MS1-A: First Optical Microstructure MS2: Second Optical Microstructure POL1, POL2: polarizer RS1: The first face of the light RS2: The third face RS3: 2nd bright side SUB1, SUB2: Substrate VD: View Control Direction w1, w2: width X, Y, Z: direction θ1, θ1’: the first angle θ2: the third angle θ3: The second included angle θ4: Fourth included angle

1A and 1B are schematic side views of the display device according to the first embodiment of the present invention in different directions, respectively. FIG. 2 is a schematic top view of some components of the display device of FIG. 1A . FIG. 3 is a schematic top view of some components of the display device of FIG. 1A . FIG. 4 is a schematic top view of another modified embodiment of some components of the display device of FIG. 1A . FIG. 5 is a schematic top view of some components of the display device of FIG. 1A . FIG. 6A is a schematic diagram illustrating the distribution of the brightness of the light emitted by different light sources to the viewing angle when the display device according to the first embodiment of the present invention operates in a sharing mode. FIG. 6B is a schematic diagram showing the distribution of total luminance versus viewing angle of the display device operating in the sharing mode according to the first embodiment of the present invention. FIG. 7 is a distribution curve diagram of normalized luminance versus viewing angle of the display device operating in the sharing mode and the privacy protection mode according to the first embodiment of the present invention. FIG. 8A is a schematic diagram illustrating the distribution of light-emitting luminances of different light sources versus viewing angles when the display device according to another modification of FIG. 1A operates in a sharing mode. FIG. 8B is a schematic diagram illustrating the distribution of total luminance versus viewing angle of the display device operating in the sharing mode according to another variant embodiment of FIG. 1A . 9A and 9B are schematic side views of the backlight module of the second embodiment of the present invention in different directions, respectively. 10A and 10B are schematic side views of the backlight module of the third embodiment of the present invention in different directions, respectively. FIG. 11A and FIG. 11B are schematic side views of the display device of the fourth embodiment of the present invention in different directions, respectively. FIG. 12 is a schematic cross-sectional view of the electronically controlled viewing angle switch of FIG. 11A . FIG. 13 is a schematic diagram illustrating the distribution of brightness versus viewing angle of the display device of FIG. 11A under different privacy protection modes.

10: Display device

100: Backlight module

110: The first light guide plate

120: Second light guide plate

110bs: first bottom surface

120bs: Second Bottom Side

110es: The first light-emitting surface

120es: The second light-emitting surface

110is1: The first light incident surface

110is2: The third light incident surface

115: The first columnar structure

125: Second column structure

130: Perspective Control Film

135: Shading Wall

140: The First Pills

150: The second celestial slice

180: The Third Pills

141: The first substrate

151: Second substrate

181: Third substrate

142: The first zodiac structure

152: The second structure

182: The third structure

160: Reflector

170: Diffuser

190: Electronically Controlled Diffusion Film

200: Display panel

h2: height

LB1, LB1", LB2: Light

LS1: The first light source

LS2: The third light source

LS3: Second light source

MS1: Optical Microstructure

RS1: The first face of the light

RS2: The third face

VD: View Control Direction

w2: width

X, Y, Z: direction

θ1: The first included angle

θ2: the third angle

Claims (19)

A backlight module, comprising: a first light guide plate having a first light incident surface, a first bottom surface and a first light emitting surface which are connected to the first light incident surface and are opposite to each other; a first light source, disposed on one side of the first light incident surface of the first light guide plate; a diffuser, disposed on one side of the first light-emitting surface of the first light guide plate; a second light guide plate disposed on one side of the first bottom surface of the first light guide plate, the second light guide plate has a second light incident surface and a second bottom surface connected to the second light incident surface and facing each other and a second light-emitting surface, the second light-emitting surface facing the first bottom surface; a second light source, disposed on one side of the second light incident surface of the second light guide plate; a viewing angle control sheet, disposed between the first light guide plate and the second light guide plate; and A first iris sheet is arranged between the viewing angle control sheet and the first light guide plate. The backlight module according to claim 1, further comprising: An electronically controlled diffusion film is disposed on one side of the first light emitting surface of the first light guide plate, and is suitable for switching operation between a scattering state and a transparent state. The backlight module of claim 2, wherein the diffusion sheet is located between the first light guide plate and the electronically controlled diffusion film. The backlight module according to claim 1, wherein the haze value of the diffusion sheet ranges from 10% to 95%. The backlight module according to claim 4, wherein the haze value of the diffusion sheet ranges from 25% to 75%. The backlight module of claim 1, wherein the first light incident surface is perpendicular to the second light incident surface. The backlight module as claimed in claim 1, wherein the first wafer has a first substrate and a plurality of first wafer structures disposed on the first substrate, and each of the first wafer structures is disposed on the first wafer. The included angle between the extension direction of the orthographic projection on the bottom surface and the first light incident surface is greater than or equal to 60 degrees and less than or equal to 120 degrees. The backlight module according to claim 7, further comprising: A second iris sheet is disposed between the viewing angle control sheet and the second light guide plate, the second iris sheet has a second substrate and a plurality of second iris structures disposed on the second substrate, and each The included angle between the extending direction of the orthographic projection of the second hexagonal structures on the first substrate and the extending direction of the orthographic projection of the first hexagonal structures on the first substrate is less than or equal to 30 degrees. The backlight module according to claim 8, further comprising: a third wafer, disposed on one side of the first light-emitting surface of the first light guide plate, the third wafer has a third substrate and a plurality of third wafer structures disposed on the third substrate, The angle between the extension direction of the orthographic projection of each of the third ridge structures on the first light-emitting surface and the first light-incident surface is less than or equal to 30 degrees. The backlight module of claim 1, wherein the first light guide plate further has a plurality of first optical microstructures disposed on the first bottom surface, and each of the first optical microstructures has a light source facing the first light source. The first light-facing surface, a first angle between the first light-facing surface and the first bottom surface is greater than or equal to 3 degrees and less than or equal to 60 degrees, and the second light guide plate also has a plurality of Second optical microstructures, each of the second optical microstructures has a second light-facing surface facing the second light source, and a second included angle between the second light-facing surface and the second bottom surface is greater than or equal to 3 degrees and less than or equal to 18 degrees. The backlight module according to claim 10, further comprising: A third light source is disposed on one side of a third light incident surface of the first light guide plate, the third light incident surface is connected to the first light exit surface and the first bottom surface, and is opposite to the first light incident surface Arrangement, wherein each of the first optical microstructures also has a third light-facing surface facing the third light source, and a third included angle between the third light-facing surface and the first bottom surface is greater than or equal to 3 degrees and less than is equal to 60 degrees. The backlight module of claim 1, wherein the first light guide plate further has a plurality of first columnar structures disposed on the first light emitting surface, and the extending directions of the first columnar structures are perpendicular to the first columnar structure. A light surface. The backlight module of claim 12, wherein each of the first columnar structures has a height along a normal direction of the first light emitting surface, and is along an extension direction of each of the first columnar structures A direction perpendicular to and parallel to the first light emitting surface has a width, and the ratio of the height to the width of each of the first columnar structures is greater than or equal to 0.1. The backlight module of claim 1, wherein the second light guide plate further has a plurality of second columnar structures disposed on the second light emitting surface, and the extending directions of the second columnar structures are perpendicular to the first Two into the light surface. The backlight module of claim 14, wherein each of the second columnar structures has a height along a normal direction of the second light emitting surface, and is along an extension direction of each of the second columnar structures A direction perpendicular to and parallel to the second light emitting surface has a width, and the ratio of the height to the width of each of the second columnar structures is greater than or equal to 0.1. The backlight module according to claim 1, further comprising: an electronically controlled viewing angle switcher, disposed on one side of the first light-emitting surface of the first light guide plate, and comprising a liquid crystal layer and at least two electrode layers disposed on opposite sides of the liquid crystal layer or disposed on the liquid crystal layer At least one electrode layer on one side. A display device, comprising: A backlight module, including: a first light guide plate having a first light incident surface, a first bottom surface and a first light emitting surface which are connected to the first light incident surface and are opposite to each other; a first light source, disposed on one side of the first light incident surface of the first light guide plate; a diffuser, disposed on one side of the first light-emitting surface of the first light guide plate; a second light guide plate disposed on one side of the first bottom surface of the first light guide plate, the second light guide plate has a second light incident surface and a second bottom surface connected to the second light incident surface and facing each other and a second light-emitting surface, the second light-emitting surface facing the first bottom surface; a second light source, disposed on one side of the second light incident surface of the second light guide plate; a viewing angle control sheet, disposed between the first light guide plate and the second light guide plate; and a first iris sheet, disposed between the viewing angle control sheet and the first light guide plate; and A display panel is arranged on one side of the first light emitting surface of the first light guide plate, and overlaps the first light emitting surface and the second light emitting surface. The display device as claimed in claim 17, wherein the backlight module further comprises: An electronically controlled diffusion film is arranged between the first light guide plate and the display panel, and is suitable for switching between a scattering state and a transparent state. The display device as claimed in claim 17, wherein the backlight module further comprises: An electronically controlled viewing angle switcher is disposed between the first light guide plate and the display panel, and includes a liquid crystal layer and at least two electrode layers disposed on opposite sides of the liquid crystal layer or disposed on one side of the liquid crystal layer. at least one electrode layer.

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