Backlight module and display device

Abstract

A backlight module comprises a first light source module, a second light source module and a light guide module. The light guide module comprises a light guide substrate and a visual angle control unit. The light guide substrate is provided with a plurality of first microstructures, a plurality of second microstructures, a first light incident surface, a second light incident surface, a light emergent surface and a bottom surface. The included angle between the first light incident face and the second light incident face is larger than or equal to 60 degrees and smaller than or equal to 120 degrees. The visual angle control unit is at least arranged on the light emitting surface and the bottom surface of the light guide substrate and is adjacent to the first light source module or is arranged between the first light incident surface and the first light source module. A first included angle is formed between the first reflecting surface of each first microstructure and the bottom surface. A second included angle is formed between the second reflecting surface of each second microstructure and the bottom surface. A display device is also provided. According to the backlight module and the display device provided by the invention, the visual angle switchable effect can be generated under the design that the thickness and the weight of the system are relatively small.

Description

TECHNICAL FIELD

[0001] The present application relates to an optical module and an optical device, and particularly relates to a backlight module and a display device. BACKGROUND

[0002] Generally, the display device with the privacy function mainly sets a switchable viewing angle control device on the light path of the illumination beam of the backlight module, so that the display device can be switched between the privacy mode and the sharing mode. However, the switchable viewing angle control device must be matched with the light collecting type backlight module or matched with the general backlight module plus the louver film to achieve good privacy effect.

[0003] However, the above display device still has the following disadvantages. First, the switchable viewing angle control device increases the thickness and weight of the display device and increases the cost. Second, the light emitting viewing angle in the sharing mode is still smaller than that of the general display device, resulting in poor user experience.

[0004] The background section of this document is included in advance to assist with understanding the detailed description. Accordingly, the background section may include ideas that are not prior art to the claimed application. Nothing disclosed in the background section should be assumed to be prior art merely because it is mentioned in the background section. SUMMARY

[0005] The present application provides a backlight module and a display device, which can produce a switchable viewing angle effect under the design of smaller system thickness and weight, and provide a larger light emitting angle in the sharing mode.

[0006] Other objects and advantages of the present application can be further understood from the technical features disclosed by the present application.

[0007] To achieve one or some or all of the above-mentioned objects or other objects, a backlight module includes a first light source module, a second light source module, and a light guide module. The light guide module includes a light guide substrate and a viewing angle control unit. The light guide substrate has a plurality of first microstructures, a plurality of second microstructures, a first light-in surface, a second light-in surface, a light-out surface, and a bottom surface. The light-out surface is opposite to the bottom surface. The first light source module is disposed corresponding to the first light-in surface, and the second light source module is disposed corresponding to the second light-in surface. An included angle between the first light-in surface and the second light-in surface is greater than or equal to 60 degrees and less than or equal to 120 degrees. The viewing angle control unit is disposed at least on the light-out surface and the bottom surface of the light guide substrate and adjacent to the first light source module or between the first light-in surface and the first light source module. A first reflection surface of each of the first microstructures faces the first light-in surface. A second reflection surface of each of the second microstructures faces the second light-in surface. The first reflection surface has a first included angle with the bottom surface. The second reflection surface has a second included angle with the bottom surface.

[0008] To achieve one or some or all of the above-mentioned objects or other objects, an embodiment of the present application provides a display device including the above-mentioned backlight module and a display panel. The display panel is disposed on the backlight module.

[0009] Based on the above, in the backlight module and the display device using the backlight module of an embodiment of the present application, the viewing angle control unit is disposed on the light guide substrate and adjacent to the first light source module or between the first light-in surface of the light guide substrate and the first light source module. Therefore, when the system is in the sharing mode, the second light source module is turned on, and the divergence angle of the light beam emitted by the second light source module is substantially maintained during transmission. Conversely, when the system is in the privacy mode, the first light source module is turned on, and the divergence angle of the light beam emitted by the first light source module is effectively reduced by the viewing angle control unit. Moreover, the light guide substrate has a plurality of first microstructures and a plurality of second microstructures, and the first reflection surface of the first microstructure has a first included angle with the bottom surface of the light guide substrate. Therefore, in the privacy mode, the light energy of the system can be maintained in the center of the viewing angle. In this way, the backlight module / display device can produce the effect of switchable viewing angle under the design of small system thickness and weight. Moreover, the light beam (most of the light beams) emitted by the second light source module will not be transmitted to the viewing angle control unit during transmission, so that the light-out angle of the system in the sharing mode is larger, thereby providing a better experience for the viewer. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 is a schematic diagram of a display device according to an embodiment of the present application.

[0011] Figure 2 is Figure 1 a top view schematic diagram of the backlight module in

[0012] Figure 3 isFigure 1 Schematic diagram of the first microstructure and the second microstructure of the backlight module.

[0013] Figure 4 is a schematic diagram of a backlight module according to a first embodiment of the present invention.

[0014] Figure 5 FIG2 is a schematic diagram of a backlight module according to an embodiment of the present invention, showing the light shape of a light beam emitted from a first light source module after emitting light from a light emitting surface of the backlight module.

[0015] Figure 6 FIG. 1 is a schematic diagram of a backlight module according to an embodiment of the present invention, showing the light shape of a light beam emitted from a second light source module after emitting light from a light emitting surface of the backlight module.

[0016] Figure 7 is a schematic diagram of a backlight module according to a second embodiment of the present invention.

[0017] Figure 8 is a schematic diagram of a backlight module according to a third embodiment of the present invention.

[0018] Figure 9 is a schematic diagram of a backlight module according to a fourth embodiment of the present invention.

[0019] Figure 10 is a schematic diagram of a backlight module according to a fifth embodiment of the present invention.

[0020] Figure 11 is a schematic diagram of a backlight module according to a sixth embodiment of the present invention.

[0021] Figure 12 is a schematic diagram of a backlight module according to a seventh embodiment of the present invention.

[0022] Figure 13 is a schematic diagram of a backlight module according to an eighth embodiment of the present invention.

[0023] Figure 14 is a schematic diagram of a backlight module according to a ninth embodiment of the present invention.

[0024] Description of reference numerals:

[0025] 10: Display device

[0026] 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H: Backlight module

[0027] 110: First light source module

[0028] 120: Second light source module

[0029] 130: light guide module

[0030] 132, 132H: light guide substrate

[0031] 134, 134A, 134B, 134C, 134D, 134E, 134F, 134G: view angle control unit

[0032] 140: reflector

[0033] 200: display panel

[0034] 2100: first microstructure

[0035] 2200: second microstructure

[0036] 2300H: first light guide substrate

[0037] 2400H: second light guide substrate

[0038] 4100: light absorbing layer

[0039] 4200A: light transmitting layer

[0040] 4300B: microstructure

[0041] 4400D, 4400E: collimator

[0042] 4420: first prism structure

[0043] 4400: second prism structure

[0044] 4500F: view angle controller

[0045] B: bottom surface

[0046] E1: first light incident surface

[0047] E2: second light incident surface

[0048] ER: empty region

[0049] H: thickness

[0050] L, L': width

[0051] L1: first light beam

[0052] L1': part

[0053] L2: second light beam

[0054] O: light exit surface

[0055] R1: first reflection surface

[0056] R1': first side reflection surface

[0057] R2’: second side reflective surface

[0058] R2: second reflective surface

[0059] β1: first included angle

[0060] β2: second included angle

[0061] β3: third included angle

[0062] β4: fourth included angle

[0063] θ1, θ2, θ3, θ4, θ5, θ6: divergence angle DETAILED DESCRIPTION

[0064] The aforementioned and other features and advantages of the present application will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0065] Figure 1 is a schematic view of a display device according to an embodiment of the present application. Figure 2 is a top view of a backlight module in Figure 1 Figure 3 is a schematic view of a first microstructure and a second microstructure of a backlight module in Figure 1 Figure 4 is a schematic view of a backlight module according to a first embodiment of the present application. Please refer to Figures 1 to 4 An embodiment of the present application provides a display device 10, which includes a backlight module 100 and a display panel 200. The display panel 200 is disposed on the backlight module 100. The display panel 200 is, for example, a liquid crystal display panel or other non-self-luminous display panel, but the present application is not limited thereto.

[0066] In the present embodiment, the backlight module 100 includes a first light source module 110, a second light source module 120, and a light guide module 130. The light guide module 130 includes a light guide substrate 132 and a viewing angle control unit 134. The light guide substrate 132 has a plurality of first microstructures 2100, a plurality of second microstructures 2200, a first light entrance surface E1, a second light entrance surface E2, a light exit surface O, and a bottom surface B. The light exit surface O is opposite to the bottom surface B. The bottom surface B (the light exit surface O) is, for example, connected to the first light entrance surface E1 and the second light entrance surface E2.

[0067] ​​In the embodiment, the first light source module 110 is arranged corresponding to the first light entrance surface E1, and the second light source module 120 is arranged corresponding to the second light entrance surface E2. The first light source module 110 and the second light source module 120 can be composed of a plurality of light sources, which can be light emitting diodes, sub-millimeter light emitting diodes or micro light emitting diodes, but the present application is not limited thereto. The first light source module 110 is used to emit the first light beam L1, and the second light source module 120 is used to emit the second light beam L2. The first light beam L1 and the second light beam L2 enter the light guide substrate 132 and then propagate in the light guide substrate 132. The backlight module 100 can selectively include a reflector 140, and the light guide substrate 132 is arranged between the reflector 140 and the display panel 200. The reflector 140 is used to reflect / recycle the light emitted from the bottom surface B of the light guide substrate 132, so as to propagate back to the light guide substrate 132. In another embodiment, the backlight module 100 can selectively arrange (e.g. coat or coat) a reflective layer on the bottom surface B of the light guide substrate 132, which is used to reflect the light beam propagating to the bottom surface B.

[0068] In the embodiment, the included angle a between the first light entrance surface E1 and the second light entrance surface E2 is greater than or equal to 60 degrees and less than or equal to 120 degrees, for example, 90 degrees.

[0069] In the embodiment, as Figure 1 and Figure 3As shown, the first microstructures 2100 and the second microstructures 2200 are disposed on the bottom surface B, and the first reflective surface R1 of each first microstructure 2100 faces the first light entrance surface E1 (e.g., the intersection line between the first reflective surface R1 and the bottom surface B has an angle less than 15 degrees with the first light entrance surface E1). The second reflective surface R2 of each second microstructure 2200 faces the second light entrance surface E2 (e.g., the intersection line between the second reflective surface R2 and the bottom surface B has an angle less than 15 degrees with the second light entrance surface E2). The first reflective surface R1 is, for example, a plane, and the first reflective surface R1 has a first angle β1 with the bottom surface B. The second reflective surface R2 is, for example, a plane, and the second reflective surface R2 has a second angle β2 with the bottom surface B. The first angle β1 is not equal to the second angle β2. In an embodiment, the first angle β1 is, for example, greater than or equal to 35 degrees and less than or equal to 55 degrees, and the second angle β2 is, for example, greater than or equal to 20 degrees and less than or equal to 30 degrees, or greater than or equal to 65 degrees and less than or equal to 75 degrees. In a preferred embodiment, the first angle β1 is equal to 45 degrees. The first angle β1 and the second angle β2 are, for example, used to adjust the direction of the main beam (maximum brightness) of the light distribution of the first light beam L1 and the second light beam L2, respectively, through the light exit surface O. For example, in an embodiment, when two pieces of orthogonal positive prism sheets (the prism extension direction of the positive prism sheet farther away from the light guide substrate 132 is, for example, parallel to the second light entrance surface E2, but is not limited thereto) or inverse prism sheets (the prism extension direction of the inverse prism sheet is, for example, parallel to the second light entrance surface E2, but is not limited thereto) are arranged on one side of the light exit surface O of the light guide substrate 132 (or multiple prism sheets are arranged), either the first light beam L1 or the second light beam L2 can be directed to approach normal light exit. In other embodiments, for example, when the first light beam L1 or the second light beam L2 needs to be directed to the same or different specific directions, the first angle β1 can be equal to the second angle β2.

[0070] In the present embodiment, each first microstructure further comprises a first side reflective surface R1’ facing the second light entrance surface E2. Each second microstructure 2200 further comprises a second side reflective surface R2’ facing the first light entrance surface E1. The first side reflective surface R1’ has a third angle β3 with the bottom surface B. The second side reflective surface R2’ has a fourth angle β4 with the bottom surface B. The difference between the fourth angle β4 and the first angle β1 is less than ±5 degrees, and the difference between the third angle β3 and the second angle β2 is less than ±5 degrees. In a preferred embodiment, the third angle β3 is equal to the second angle β2, and the fourth angle β4 is equal to the first angle β1.

[0071] In the present embodiment, the viewing angle control unit 134 is disposed on the light guide substrate 132 and adjacent to the first light source module 110, as shown in FIG. 1A. Figure 2 and Figure 4As shown in the schematic view, the projection area of the light-out surface O of the light guide substrate 132 is a first projection area, and the projection area of the display area (not shown in the figure, for example, the area of the display panel 200 displaying the image) of the display panel 200 on the light-out surface O is a second projection area. The first projection area and the second projection area are not overlapped (i.e., there is a spacing between the two projection areas), and the first projection area is located between the second projection area and the first light source module 110. In an embodiment, the first projection area is not overlapped with the projection area of the first microstructure 2100 and the second microstructure 2200 on the light-out surface O.

[0072] In the embodiment, the view angle control unit 134 is disposed on the light-out surface O and the bottom surface B of the light guide substrate 132, and the view angle control unit 134 includes the light-absorbing layer 4100. The material of the light-absorbing layer 4100 is, for example, a light-absorbing material with a light absorption rate greater than 90%, and most of the light transmitted to the light-absorbing layer 4100 will be absorbed by the light-absorbing layer 4100. The ratio (H / L) of the thickness H of the light guide substrate 132 (the thickness of the light guide substrate 132 in the direction perpendicular to the bottom surface B) to the width L of the light-absorbing layer 4100 (the width of the light-absorbing layer 4100 in the direction perpendicular to the first light-in surface E1) is less than or equal to 0.5 or 0.4. The light guide substrate 132 has a blank area ER between the light-absorbing layer 4100 and the first light source module 110. That is, the blank area ER and the light-absorbing layer 4100 are non-optically effective areas of the display device 10 or the backlight module 100. In an embodiment, the width of the blank area ER in the direction of the first light-in surface E1 is less than twice the width L of the light-absorbing layer 4100. In other embodiments, the edge of the light-absorbing layer 4100 can be flush with the first light-in surface E1, that is, there is no blank area ER. In an embodiment, the width of the light guide substrate 132 and the light-absorbing layer 4100 (view angle control unit 134) in the direction perpendicular to the second light-in surface E2 is, for example, the same, as shown in the figure. Figure 2

[0073] ​In the privacy mode of the present embodiment, the second light source module 120 does not emit light beams, and the first light beam L1 is emitted from the first light source module 110, enters the light guide substrate 132 via the first light entrance surface E1, and propagates in the light guide substrate 132. Part of the first light beam L1 continues to propagate in the light guide substrate 132 by passing through the section of the light absorption layer 4100, while another part of the first light beam L1 is absorbed by the light absorption layer 4100. Further, the divergence angle of the first light beam L1 after being emitted from the first light source module 110 is θ1 (for example, the half-width of the light distribution), and the divergence angle of the part of the first light beam L1 after passing through the section of the light absorption layer 4100 is θ2. The part of the first light beam L1 propagates to the first reflective surface R1 of the first microstructure 2100 or the second side reflective surface R2’ of the second microstructure 2200, is reflected by the first reflective surface R1 or the second side reflective surface R2’ to the light exit surface O, and is emitted from the light exit surface O. Here, the divergence angle θ2 < the divergence angle θ1. Therefore, the viewing angle control unit 134 / light absorption layer 4100 effectively reduces the divergence angle θ1 of the first light beam L1, so that the backlight module 100 has the effect of reducing the light exit range (for example, the half-width of the light exit), and the display device 10 has the privacy function.

[0074] In the sharing mode of the present embodiment, the second light beam L2 is emitted from the second light source module 120, enters the light guide substrate 132, and propagates in the light guide substrate 132. The second light beam L2 propagates to the second reflective surface R2 of the second microstructure 2200 or the first side reflective surface R1’ of the first microstructure 2100, is reflected by the second reflective surface R2 or the first side reflective surface R1’ to the light exit surface O, and is emitted from the light exit surface O. Therefore, the divergence angle of the second light beam L2 is substantially unchanged during the propagation process, forming the sharing mode of the display device 10. In the sharing mode of the present embodiment, the first light source module 110 can selectively emit or not emit light beams.

[0075] Figure 5 is a schematic diagram of the light exit shape of the light beam emitted from the first light source module and emitted from the light exit surface of the backlight module according to an embodiment of the present application. Figure 6 is a schematic diagram of the light exit shape of the light beam emitted from the second light source module and emitted from the light exit surface of the backlight module according to an embodiment of the present application. Please refer to Figure 5 and Figure 6Based on the above, in a backlight module 100 and a display device 10 using the backlight module 100 according to an embodiment of the present invention, the backlight module 100 includes a first light source module 110, a second light source module 120 and a light guide module 130. The light guide module 130 includes a light guide substrate 132 and a viewing angle control unit 134. The viewing angle control unit 134 is disposed on the light guide substrate 132 and adjacent to the first light source module 110. Therefore, when the system is in sharing mode, the second light source module 120 is turned on (in another embodiment, the first light source module 110 and the second light source module 120 are turned on at the same time), and the divergence angle of the light beam emitted by the second light source module 120 remains substantially unchanged during the transmission process, so the light output shape of the light beam after exiting the light output surface of the backlight module 100 is as follows: Figure 6 As shown, the light emitting range is relatively wide in the first axial direction (e.g., horizontal viewing angle), and the first axial direction is, for example, perpendicular to the first light incident surface E1. On the contrary, when the system is in the anti-peeping mode, only the first light source module 110 is turned on, and the divergence angle of the light beam emitted by the first light source module 110 is effectively reduced by the viewing angle control unit 134. Therefore, the light beam has a light shape after exiting the light exit surface of the backlight module 100. Figure 5 In one embodiment, the light emitting pattern of the backlight module 100 in the sharing mode has a first half-height width (for example, in the first axis), and the light emitting pattern of the backlight module 100 in the anti-peeping mode has a second half-height width (for example, in the first axis), and the ratio of the second half-height width to the first half-height width is, for example, less than or equal to 3 / 4 (for example, 1 / 6, as shown in FIG. Figure 5 and Figure 6 As shown). Moreover, the light guide substrate 132 has a plurality of first microstructures 2100 and a plurality of second microstructures 2200. The first reflective surface R1 of the first microstructure 2100 and the bottom surface B of the light guide substrate 132 form a first angle β1. The backlight module 100 is designed such that the first angle β1 is greater than or equal to 35 degrees and less than or equal to 55 degrees. Therefore, as Figure 5 As shown, in privacy mode, the system's light energy is maintained in the central area of ​​the viewing angle. This allows the backlight module 100 / display device 10 to achieve a switchable viewing angle while maintaining a low-thickness and low-weight design. Furthermore, the primary light beam emitted by the second light source module 120 is not transmitted to the viewing angle control unit 134 during transmission, resulting in a wider light output angle in sharing mode, further enhancing the viewer's experience.

[0076] Figure 7 is a schematic diagram of a backlight module according to a second embodiment of the present invention. Figure 7 , the backlight module 100A and Figure 4The backlight module 100B is similar to the backlight module 100 of the first embodiment, and the main difference is that the viewing angle control unit 134B includes a plurality of microstructures 4300B in the present embodiment. Each microstructure 4300B is in the shape of a prism column, and the cross section of each microstructure 4300B is, for example, triangular. Each microstructure 4300B extends along the direction parallel to the first light-incident surface E1. The ratio of the thickness H of the light guide substrate 132 to the arrangement width L' of the plurality of microstructures 4300B on the light guide substrate 132 is less than or equal to 0.5 or 0.4. In a preferred embodiment, the viewing angle control unit 134B further includes an absorbing layer as shown in FIG. 43B, and the absorbing layer is arranged on the microstructures 4300B, which can effectively reduce the system stray light.

[0077] Figure 8 FIG. 44 is a schematic view of a backlight module according to a third embodiment of the present application. Please refer to FIG. 44, Figure 8 The backlight module 100B is similar to the backlight module 100 of the first embodiment, and the main difference is that the viewing angle control unit 134B includes a plurality of microstructures 4300B in the present embodiment. Each microstructure 4300B is in the shape of a prism column, and the cross section of each microstructure 4300B is, for example, triangular. Each microstructure 4300B extends along the direction parallel to the first light-incident surface E1. The ratio of the thickness H of the light guide substrate 132 to the arrangement width L' of the plurality of microstructures 4300B on the light guide substrate 132 is less than or equal to 0.5 or 0.4. In a preferred embodiment, the viewing angle control unit 134B further includes an absorbing layer as shown in FIG. 43B, and the absorbing layer is arranged on the microstructures 4300B, which can effectively reduce the system stray light. Figure 4 Figure 4

[0078] Figure 9 FIG. 45 is a schematic view of a backlight module according to a fourth embodiment of the present application. Please refer to FIG. 45, Figure 9 The backlight module 100C is similar to the backlight module 100B of the third embodiment, and the main difference is that the microstructures 4300C of the viewing angle control unit 134C are in the shape of a semi-cylinder in the present embodiment. In a preferred embodiment, the viewing angle control unit 134C further includes an absorbing layer as shown in FIG. 43C, and the absorbing layer is arranged on the microstructures 4300C, which can effectively reduce the system stray light. Figure 8 Figure 4

[0079] Figure 10 FIG. 46 is a schematic view of a backlight module according to a fifth embodiment of the present application. Please refer to FIG. 46, Figure 10 The backlight module 100D is similar to the backlight module 100C of the fourth embodiment, and the main difference is that the microstructures 4300D of the viewing angle control unit 134D are in the shape of a semi-cylinder in the present embodiment. In a preferred embodiment, the viewing angle control unit 134D further includes an absorbing layer as shown in FIG. 43D, and the absorbing layer is arranged on the microstructures 4300D, which can effectively reduce the system stray light. Figure 4 ​​​​The backlight module 100 is similar to the backlight module 100, with the main difference being that in this embodiment, the viewing angle control unit 134D further includes a collimator 4400D. The collimator 4400D is disposed between the first light source module 110 and the light guide substrate 132, that is, the viewing angle control unit 134D is disposed on the light guide substrate 132 and adjacent to the first light source module 110 and between the first light source module 110 and the light guide substrate 132. The width of the collimator 4400D and the light guide substrate 132 (or the first light source module 110) in the direction perpendicular to the second light incident surface E2 is, for example, the same. The collimator 4400D includes a plurality of first prism structures 4420. The vertex angle of the first prism structure 4420 faces toward or faces away from the first light incident surface E1 (the first prism structure 4420 is disposed on a side surface of the collimator 4400D facing toward or facing away from the first light incident surface E1). The first prism structure 4420 extends in a direction parallel to the first light incident surface E1. The extension direction of the first prism structure 4420 may be, for example, parallel to or perpendicular to the arrangement direction of the multiple light sources of the first light source module 110. In one embodiment, the first prism structure 4420 extends in a direction parallel to the first light incident surface E1 and the light exit surface O. Furthermore, the divergence angle θ3 of the first light beam L1 after passing through the collimator 4400D is less than the divergence angle θ1. This creates a light-collecting effect before the first light beam L1 is transmitted to the light guide substrate 132, narrowing the range of incident angles of the first light beam L1 entering the first light incident surface E1 and reducing light energy loss.

[0080] Figure 11 is a schematic diagram of a backlight module according to a sixth embodiment of the present invention. Figure 11 , the backlight module 100E and Figure 10 The collimator 4400E in the viewing angle control unit 134E is similar to the backlight module 100D, with the main difference being that in this embodiment, the collimator 4400E in the viewing angle control unit 134E includes a plurality of first prism structures 4420 and a plurality of second prism structures 4400. The vertex angles of the first prism structures 4420 are opposite to the vertex angles of the second prism structures 4440. The first prism structures 4420 and the second prism structures 4440 extend in a direction parallel to the first light incident surface E1. The respective extension directions of the first prism structures 4420 and the second prism structures 4440 are, for example, parallel to or perpendicular to the arrangement direction of the multiple light sources of the first light source module 110. In one embodiment, the first prism structures 4420 and the second prism structures 4440 extend in a direction parallel to the first light incident surface E1 and the light exit surface O. In addition, the divergence angle θ4 of the first light beam L1 after passing through the collimator 4400D is less than the divergence angle θ1. In this way, a light-collecting effect can be generated before the first light beam L1 is transmitted to the light-guiding substrate 132 , thereby narrowing the incident angle range of the first light beam L1 entering the first light incident surface E1 and reducing light energy loss.

[0081] Figure 12 is a schematic diagram of a backlight module according to a seventh embodiment of the present invention.Figure 12 The backlight module 100F is similar to the backlight module 100 of Figure 4 The main difference between the backlight module 100F and the backlight module 100 of The main difference between the backlight module 100F and the backlight module 100 of

[0082] The main difference between the backlight module 100F and the backlight module 100 of Figure 13 The main difference between the backlight module 100F and the backlight module 100 of Figure 13 The backlight module 100G is similar to the backlight module 100E of Figure 11 The main difference between the backlight module 100G and the backlight module 100E of Figure 12 The main difference between the backlight module 100G and the backlight module 100F of The main difference between the backlight module 100G and the backlight module 100F of

[0083] The main difference between the backlight module 100G and the backlight module 100F of Figure 14 The main difference between the backlight module 100G and the backlight module 100F of Figure 2 The backlight module 100H is similar to the backlight module 100 of Figure 14 The main difference between the backlight module 100H and the backlight module 100 of Figure 2 The main difference between the backlight module 100H and the backlight module 100 of The main difference between the backlight module 100H and the backlight module 100 of

[0084] In summary, in the backlight module and the display device using the same according to an embodiment of the present application, the backlight module comprises a first light source module, a second light source module and a light guide module. The light guide module comprises a light guide substrate and a viewing angle control unit. The viewing angle control unit is disposed on the light guide substrate and adjacent to the first light source module or between the first light-incident surface of the light guide substrate and the first light source module. Therefore, when the system is in the sharing mode, the second light source module is turned on, and the divergence angle of the light beam emitted by the second light source module is substantially maintained during transmission. Conversely, when the system is in the privacy mode, the first light source module is turned on, and the divergence angle of the light beam emitted by the first light source module is effectively reduced by the viewing angle control unit. Moreover, the light guide substrate has a plurality of first microstructures and a plurality of second microstructures, and the first reflective surface of the first microstructure has a first included angle with the bottom surface of the light guide substrate. Therefore, in the privacy mode, the light energy of the system can be maintained in the center of the viewing angle. In this way, the backlight module / display device can produce the effect of switchable viewing angle under the design of smaller system thickness and weight. Moreover, the main light beam emitted by the second light source module will not be transmitted to the viewing angle control unit during transmission, so that the light emission angle of the system in the sharing mode is larger, thereby providing a better experience for the viewer.

[0085] The above description is only the preferred embodiments of the present application, and cannot limit the scope of the present application. Any simple equivalent changes and modifications made according to the claims and the content of the present application are still within the scope of the present application. In addition, any embodiment or claim of the present application does not necessarily achieve all the purposes or advantages or features disclosed in the present application. In addition, the abstract and title (invention name) are only used to assist patent document retrieval, and do not limit the scope of the present application. In addition, the terms "first", "second" and the like mentioned in the specification or claims are only used to name elements or distinguish different embodiments or ranges, and do not limit the upper or lower limit of the number of elements.

Claims

1. A backlight module, characterized in that: The backlight module includes a first light source module, a second light source module and a light guide module, wherein: The light guide module includes a light guide substrate and a viewing angle control unit, wherein the light guide substrate has a plurality of first microstructures, a plurality of second microstructures, a first light incident surface, a second light incident surface, a light exit surface, and a bottom surface, the light exit surface is opposite to the bottom surface, the first light source module is arranged corresponding to the first light incident surface, and the second light source module is arranged corresponding to the second light incident surface, and the angle between the first light incident surface and the second light incident surface is greater than or equal to 60 degrees and less than or equal to 120 degrees, The viewing angle control unit is at least arranged on the light-emitting surface and the bottom surface of the light-guiding substrate and is adjacent to the first light source module or is arranged between the first light incident surface and the first light source module, the first reflection surface of each of the multiple first microstructures faces the first light incident surface, the second reflection surface of each of the multiple second microstructures faces the second light incident surface, the first reflection surface has a first angle with the bottom surface, and the second reflection surface has a second angle with the bottom surface.

2. The backlight module according to claim 1, wherein: The multiple first microstructures and the multiple second microstructures are arranged on the bottom surface, each of the multiple first microstructures also includes a first side reflection surface, and each of the multiple second microstructures also includes a second side reflection surface, the first side reflection surface and the bottom surface have a third angle, the second side reflection surface and the bottom surface have a fourth angle, the fourth angle is equal to the first angle, and the third angle is equal to the second angle.

3. The backlight module according to claim 1, wherein: The viewing angle control unit is arranged on the light emitting surface and the bottom surface of the light guide substrate, and the viewing angle control unit includes a light absorbing layer. The ratio of the thickness of the light guide substrate to the width of the light absorption layer is less than or equal to 0.

5.

4. The backlight module according to claim 1, wherein: The viewing angle control unit is arranged on the light emitting surface and the bottom surface of the light guide substrate, and the viewing angle control unit includes a light absorbing layer and a light transmitting layer, and the light transmitting layer is arranged between the light absorbing layer and the light guide substrate. The condition 0≤the refractive index of the light-guiding substrate minus the refractive index of the light-transmitting layer≤0.4 is satisfied.

5. The backlight module according to claim 1, wherein: The viewing angle control unit includes a plurality of microstructures, wherein: The plurality of microstructures are in a prism shape or a semi-cylinder shape, and the plurality of microstructures extend in a direction parallel to the first light incident surface.

6. The backlight module according to claim 1, wherein: The viewing angle control unit includes a collimator, wherein: The collimator is disposed between the first light source module and the light guide substrate, wherein the collimator includes a plurality of first prism structures, and the vertex angles of the plurality of first prism structures face toward or away from the first light incident surface.

7. The backlight module according to claim 6, wherein: The collimator includes the plurality of first prism structures and a plurality of second prism structures, wherein the plurality of vertex corners of the plurality of first prism structures face away from the vertex corners of the plurality of second prism structures.

8. The backlight module according to claim 1, wherein: The viewing angle control unit includes a viewing angle controller, wherein: The viewing angle controller is disposed between the first light source module and the light guide substrate.

9. The backlight module according to claim 1, wherein: The viewing angle control unit includes a collimator and a viewing angle controller, wherein: The collimator is disposed between the first light source module and the light guide substrate; and The viewing angle controller is arranged between the collimator and the light guide substrate.

10. The backlight module according to claim 1, wherein: The light guide substrate includes a first light guide substrate and a second light guide substrate, the first light incident surface and the light exit surface are located on the first light guide substrate, the second light incident surface and the bottom surface are located on the second light guide substrate, the viewing angle control unit is arranged on the first light guide substrate and is adjacent to the first light source module or is arranged between the first light incident surface and the first light source module, the multiple first microstructures are arranged on the surface of the first light guide substrate, and the multiple second microstructures are arranged on the bottom surface of the second light guide substrate.

11. A display device, characterized in that: The display device includes a backlight module and a display panel, wherein: The backlight module is the backlight module according to any one of claims 1 to 10; and The display panel is disposed on the backlight module.

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