Backlight module and display device

Abstract

The invention discloses a backlight module which comprises a switching control unit, a first light source unit, a second light source unit and a first prismatic lens. The first light source unit is located below the switching control unit and comprises a first light source and a first light guide plate. The second light source unit is located between the switching control unit and the first light source unit and comprises a second light source and a second light guide plate. The first prismatic lens is arranged on the light emitting side of the first light guide plate, and in the peep-proof mode, the second light source is turned off, the first light source is turned on, and the switching control unit is turned on to regulate and control light of the first light source unit passing through the first prismatic lens, so that the backlight module has a first light emitting range; in the non-peep-proof mode, the second light source is turned on, and the switching control unit is turned off, so that the backlight module has a second light emitting range, and the second light emitting range is larger than the first light emitting range.

Description

Technical Field

[0001] The present invention relates to a backlight module; specifically, the present invention relates to a backlight module capable of switching light emission modes and a display device having the backlight module. Background Art

[0002] Existing display devices usually achieve the effect of privacy protection by installing privacy films to filter large-angle light. However, the installation of privacy films generally affects the display quality and brightness, and the output power of the light source must be increased to achieve the expected brightness requirements. Furthermore, privacy films usually cannot achieve the effect of partial privacy protection. Summary of the invention

[0003] An object of the present invention is to provide a backlight module which can be switched between an anti-peeping mode and a non-anti-peeping mode.

[0004] In one embodiment, the backlight module of the present invention includes: a switching control unit, a first light source unit, a second light source unit and a first prism sheet, wherein the first light source unit is located below the switching control unit and includes a first light source and a first light guide plate; the second light source unit is located between the switching control unit and the first light source unit and includes a second light source and a second light guide plate, wherein in the anti-peeping mode, the second light source is turned off, the first light source is turned on, and the switching control unit is activated to regulate the light of the first light source unit through the first prism sheet so that the backlight module has a first light emitting range; in the non-anti-peeping mode, the second light source is turned on and the switching control unit is turned off, so that the backlight module has a second light emitting range, and the second light emitting range is larger than the first light emitting range.

[0005] In one embodiment, in the non-peeping mode, the first light source is turned on, and the second light emission range is formed by the light emitted by the first light source unit and the second light source unit.

[0006] In one embodiment, the first prism sheet has a plurality of first prism strips extending along a first direction.

[0007] In one embodiment, the backlight module of the present invention further includes a second prism sheet, wherein the second prism sheet has a plurality of second prism strips extending along a second direction, and the second direction is substantially perpendicular to the first direction.

[0008] In one embodiment, the second prism sheet is disposed on the light-emitting side of the first light guide plate and is located between the first light guide plate and the second light guide plate.

[0009] In one embodiment, the second prism sheet is disposed on the light emitting side of the second light guide plate.

[0010] In one embodiment, the backlight module of the present invention further includes a reflective layer disposed on the side opposite to the light emitting side of the first light guide plate.

[0011] In one embodiment, the backlight module of the present invention further includes an optical film disposed on the light emitting side of the first light guide plate.

[0012] In one embodiment, the second light source includes a first sub-light source and a second sub-light source, and the switching control unit includes a first control area and a second control area, which correspond to the first sub-light source and the second sub-light source respectively, wherein in the local anti-peep mode, the first light source is turned on, the first sub-light source is selectively turned on or off, and the second sub-light source is turned off, the switching control unit turns off the first control area and starts the second control area, so that the backlight module has a third light emitting range and a fourth light emitting range, wherein the third light emitting range substantially corresponds to the first control area, the fourth light emitting range substantially corresponds to the second control area, and the fourth light emitting range is smaller than the third light emitting range.

[0013] In one embodiment, in the partial privacy protection mode, the first sub-light source is turned on to increase the third light output range.

[0014] In one embodiment, the brightness ratio of the first light source to the second light source is 2:1.

[0015] Another object of the present invention is to provide a backlight module which can effectively provide a partial privacy protection effect.

[0016] In one embodiment, the backlight module of the present invention includes: a switching control unit, a first light source unit, a second light source unit and a first prism sheet, wherein the switching control unit has a first control area and a second control area; the first light source unit is located below the switching control unit and includes a first light source and a first light guide plate; the second light source unit is located between the switching control unit and the first light source unit and includes a second light source and a second light guide plate, the second light source includes a first sub-light source and a second sub-light source corresponding to the first control area and the second control area respectively, wherein in a local anti-peeping mode, the first light source is turned on, the first sub-light source is selectively turned on or off, and the second sub-light source is turned off, the switching control unit turns off the first control area and starts the second control area, so that the backlight module has a non-anti-peeping light-emitting range that substantially corresponds to the first control area and an anti-peeping light-emitting range that substantially corresponds to the second control area, and the anti-peeping light-emitting range is smaller than the non-anti-peeping light-emitting range.

[0017] In another embodiment, the present invention provides a display device, which includes a display panel and the above-mentioned backlight module, wherein the display panel has a display surface, and the backlight module is disposed on the opposite side of the display surface of the display panel.

[0018] Compared with the prior art, the backlight module of the present invention can provide a more uniform brightness-viewing angle distribution in the non-peeping mode, effectively improving energy consumption. Furthermore, the backlight module of the present invention can provide a more concentrated brightness-viewing angle distribution in the anti-peeping mode, effectively improving the anti-peeping effect. In addition, the backlight module of the present invention can effectively provide a local anti-peeping effect by switching the control unit and the local control of the light source. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a three-dimensional schematic diagram of a display device and a backlight module thereof according to a first embodiment of the present invention.

[0020] Figure 1A and Figure 1B They are Figure 1 Schematic diagram of the light emission range of a display device and its backlight module in an anti-peeping mode and a non-anti-peeping mode.

[0021] Figure 2 FIG. 4 is a perspective schematic diagram of a display device and a backlight module thereof according to a second embodiment of the present invention.

[0022] Figure 3 FIG. 4 is a perspective schematic diagram of a display device and a backlight module thereof according to a third embodiment of the present invention.

[0023] Figure 4 FIG. 4 is a perspective schematic diagram of a display device and a backlight module thereof according to a fourth embodiment of the present invention.

[0024] Figure 5 FIG. 5 is a perspective schematic diagram of a display device and a backlight module thereof according to a fifth embodiment of the present invention.

[0025] Figure 6 FIG. 1 is a schematic diagram of brightness-angle distribution curves of a backlight module according to an embodiment of the present invention and a conventional backlight module in a non-peeping mode.

[0026] Fig. 7A FIG. 1 is a schematic diagram of brightness-angle distribution curves of a backlight module according to an embodiment of the present invention and a conventional backlight module in an anti-peeping mode.

[0027] Figure 7B for Fig. 7A A partial enlarged view of .

[0028] Figure 8 FIG. 4 is a perspective schematic diagram of a display device and a backlight module thereof according to a sixth embodiment of the present invention.

[0029] Figure 8A-1 and Figure 8A-2 for Figure 8 Schematic diagram of the light emission range of a display device and its backlight module in different local anti-peeping modes.

[0030] Figure 8B and Figure 8C They are Figure 8 Schematic diagram of the light emission range of a display device and its backlight module in an anti-peeping mode and a non-anti-peeping mode.

[0031] Fig.9A FIG. 4 is a schematic diagram of a switching control unit according to an embodiment of the present invention.

[0032] Fig. 9B for Fig.9A Schematic diagram of the orientation of some components of the switching control unit.

[0033] Wherein, the reference numerals are:

[0034] 1, 2, 3, 4, 5, 6 display devices

[0035] 10, 10A, 10B, 10C, 10D, 10E backlight module

[0036] 20 Display Panel

[0037] 201 display surface

[0038] 202 back side

[0039] 110 first light source unit

[0040] 112 First Light Source

[0041] 112a Light emitting parts

[0042] 114 first light guide plate

[0043] 114a light output side

[0044] 120 second light source unit

[0045] 122 Second Light Source

[0046] 122a Luminous parts

[0047] 1221 The first sub-light source

[0048] 1222 Second sub-light source

[0049] 124 second light guide plate

[0050] 124a light output side

[0051] 130 Switching control unit

[0052] 130a light output side

[0053] 132 The first regulatory region

[0054] 132a first polarizer

[0055] 132b Second polarizer

[0056] 132c Third polarizer

[0057] 134 Second regulatory region

[0058] 134a first substrate

[0059] 134b Second substrate

[0060] 134c Third substrate

[0061] 134d Fourth substrate

[0062] 135a first liquid crystal layer

[0063] 135b second liquid crystal layer

[0064] 136a first electrode

[0065] 136b Second electrode

[0066] 136c Third electrode

[0067] 136d Fourth electrode

[0068] 138a first alignment layer

[0069] 138b Second alignment layer

[0070] 138c The third alignment layer

[0071] 138d Fourth alignment layer

[0072] 140 First Prism

[0073] 142 First Prism Strip

[0074] 150 Second prism

[0075] 152 Second Prism Strip

[0076] 162, 164 optical film

[0077] 170 Reflection layer

[0078] C1, C1' curve

[0079] C2, C2' curve

[0080] D1 first direction

[0081] D2 Second direction

[0082] D3 third direction

[0083] L1 light

[0084] L2 light

[0085] VA1 first light output range

[0086] VA2 second light output range

[0087] VA3, VA3' third light output range

[0088] VA4, VA4' fourth light output range DETAILED DESCRIPTION

[0089] In the accompanying drawings, for the sake of clarity, the thickness of layers, films, panels, regions, etc. is magnified. Throughout the specification, the same reference numerals represent the same elements. It should be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" or "connected to" another element, it may be directly on or connected to another element, or an intermediate element may also exist. On the contrary, when an element is referred to as being "directly on" or "directly connected to" another element, there is no intermediate element. As used herein, "connection" may refer to physical and / or electrical connection. Furthermore, "electrical connection" or "coupling" may be the presence of other elements between two elements.

[0090] It should be understood that although the terms "first", "second", "third", etc. may be used herein to describe various elements, components, regions, layers and / or parts, these elements, components, regions, and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, the "first element", "component", "region", "layer" or "part" discussed below may be referred to as a second element, component, region, layer or part without departing from the teachings of this article.

[0091] The terms used herein are for the purpose of describing specific embodiments only and are not restrictive. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include plural forms, including "at least one". ", "or" means "and / or". As used herein, the terms "and / or" include any and all combinations of one or more of the relevant listed items. It should also be understood that when used in this specification, the terms "include" and / or "include" specify the presence and / or parts of the features, regions, entireties, steps, operations, elements, but do not exclude the presence or addition of one or more other features, regions, entireties, steps, operations, elements, parts, and / or combinations thereof.

[0092] In addition, relative terms such as "lower" or "bottom" and "upper" or "top" may be used herein to describe the relationship of one element to another element, as shown in the figures. It should be understood that relative terms are intended to include different orientations of the device in addition to the orientation shown in the figures. For example, if the device in one figure is turned over, the element described as being on the "lower" side of the other elements will be oriented on the "upper" side of the other elements. Therefore, the exemplary term "lower" can include both "lower" and "upper" orientations, depending on the specific orientation of the figure. Similarly, if the device in one figure is turned over, the element described as being "below" or "below" other elements will be oriented as being "above" other elements. Therefore, the exemplary terms "below" or "below" can include both above and below orientations.

[0093] As used herein, "about", "approximately", or "substantially" include the stated value and the average value within an acceptable deviation range of the particular value determined by one of ordinary skill in the art, taking into account the measurement in question and the particular amount of error associated with the measurement (i.e., the limitations of the measurement system). For example, "about" can mean within one or more standard deviations of the stated value, or within ±30%, ±20%, ±10%, ±5%. Furthermore, as used herein, "about", "approximately", or "substantially" can select a more acceptable deviation range or standard deviation depending on the optical property, etching property or other property, and can apply to all properties without a single standard deviation.

[0094] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology and the present invention, and will not be interpreted as an idealized or overly formal meaning unless explicitly defined as such herein.

[0095] Exemplary embodiments are described herein with reference to cross-sectional views that are schematic diagrams of idealized embodiments. Therefore, variations in the shapes of the illustrations as a result of, for example, manufacturing techniques and / or tolerances, can be expected. Therefore, the embodiments described herein should not be construed as limited to the specific shapes of the regions as shown herein, but rather include shape deviations that result, for example, from manufacturing. For example, a region shown or described as flat may typically have rough and / or nonlinear features. In addition, the sharp angles shown may be rounded. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to illustrate the precise shape of the regions and are not intended to limit the scope of the claims.

[0096] The present invention provides a backlight module. The backlight module of the present invention can be applied to a display device, so that the display device has a switchable display mode (such as an anti-peeping mode or a non-anti-peeping mode) by means of different light emission modes of the backlight module, but is not limited thereto. The details of the display device and the backlight module of the present invention will be described in detail with reference to the drawings below.

[0097] refer to Figure 1 , Figure 1 FIG. 1 is a perspective schematic diagram of a display device 1 and a backlight module 10 thereof according to a first embodiment of the present invention. Figure 1 As shown, the display device 1 includes a backlight module 10 and a display panel 20. The display panel 20 can be any display panel that requires the backlight module 10 as a backlight source, such as a liquid crystal display panel, but is not limited thereto. The backlight module 10 is disposed on the opposite side of the display surface 201 of the display panel 20. For example, with the display surface 201 of the display panel 20 as the front side, the backlight module 10 is disposed on the back side 202 of the display panel 20.

[0098] like Figure 1 As shown, the backlight module 10 includes a switching control unit 130, a first light source unit 110, a second light source unit 120 and a first prism sheet 140. The first light source unit 110 is located below the switching control unit 130 and includes a first light source 112 and a first light guide plate 114. The second light source unit 120 is located between the switching control unit 130 and the first light source unit 110 and includes a second light source 122 and a second light guide plate 124. The first prism sheet 140 is disposed on the light exit side 114a of the first light guide plate 114. In the anti-peeping mode (such as Figure 1A ), the second light source 122 is turned off, the first light source 112 is turned on, and the switching control unit 130 is activated to regulate the light of the first light source unit 110 through the first prism sheet 140, so that the backlight module 10 has a first light emitting range (for example, VA1); in the non-peeping mode (for example, Figure 1B As shown), the second light source 122 is turned on and the switching control unit 130 is turned off, so that the backlight module 10 has a second light emitting range (eg, VA2), and the second light emitting range is larger than the first light emitting range.

[0099] Specifically, the first light source 112 is preferably a light bar composed of a plurality of light emitting elements 112a and a circuit board (not shown). For example, the light emitting elements 112a may be light emitting diodes (LEDs) or micro LEDs, and are arranged at intervals and electrically connected to a flexible circuit board to form a strip-shaped first light source 112, but is not limited thereto. The first light source 112 is preferably arranged on the side of the first light guide plate 114 to form a side light entry structure. Specifically, the first light guide plate 114 may be a rectangular plate extending along the first direction D1 and the second direction D2 (i.e., the first direction D1 is perpendicular to the second direction D2), and preferably has a size corresponding to the display panel 20. The first light source 112 may be arranged along the second direction D2 to emit light toward the first direction D1 to enter the first light guide plate 114. For example, in the display device 1, the first direction D1 may be a vertical viewing direction, the second direction D2 may be a horizontal viewing direction, and the third direction D3 may be a display direction (or a light emitting direction of the backlight module (e.g., 10)). In this embodiment, the plurality of light emitting elements 112a of the first light source 112 are disposed at the bottom of the first light guide plate 114 (i.e., at the bottom in the vertical viewing direction) along the horizontal viewing direction, so that the light emitted by the plurality of light emitting elements 112a enters the first light guide plate 114 from the bottom of the first light guide plate 114, but the present invention is not limited thereto. According to practical applications, the first light source 112 may be disposed at one or more sides of the first light guide plate 114, such as the left side and / or right side in the horizontal viewing direction and / or the top and / or bottom in the vertical viewing direction.

[0100] The second light source unit 120 has a structure similar to that of the first light source unit 110. Specifically, the second light source 122 is preferably a light bar composed of a plurality of light-emitting elements 122a and a circuit board (not shown). For example, the light-emitting elements 122a may be light-emitting diodes (LEDs) or micro-LEDs, and are arranged at intervals and electrically connected to a flexible circuit board to form a strip-shaped second light source 122, but is not limited thereto. The second light source 122 is preferably arranged on the side of the second light guide plate 124 to form a side-light-entering structure. Specifically, the second light guide plate 124 may be a rectangular plate extending along the first direction D1 and the second direction D2, and preferably has a size corresponding to the first light guide plate 114. The second light source 122 may be arranged along the second direction D2 to emit light toward the first direction D1 into the second light guide plate 124. For example, the plurality of light emitting elements 122a of the second light source 122 are disposed at the bottom of the second light guide plate 124 (i.e., below the vertical viewing direction) along the horizontal viewing direction (e.g., the second direction D2), so that the light emitted by the plurality of light emitting elements 122a enters the second light guide plate 124 from the bottom of the second light guide plate 124, but the present invention is not limited thereto. According to practical applications, the second light source 122 may be disposed at one or more sides of the second light guide plate 124, such as the left side and / or the right side in the horizontal viewing direction and / or the top and / or the bottom in the vertical viewing direction. In this embodiment, the first light source 112 and the second light source 122 are preferably located at the same side of the first light guide plate 114 and the second light guide plate 124, such as below the vertical viewing direction, but the present invention is not limited thereto. According to practical applications, the first light source 112 and the second light source 122 may be located at the same side, different sides, or multiple sides of the first light guide plate 114 and the second light guide plate 124.

[0101] The first prism sheet 140 is used to increase the central light intensity of the backlight module 10. Figure 1 As shown, the first prism sheet 140 has a plurality of first prism strips 142 extending along the first direction D1. Specifically, the plurality of first prism strips 142 are arranged along the second direction D2 and extend along the first direction D1, so that the light on both sides of the second direction D2 is concentrated toward the center, so as to provide a better optical effect. For example, taking the extension direction of the prism strip parallel to the horizontal viewing direction (such as the second direction D2) as 0 degrees, the plurality of first prism strips 142 of the first prism sheet 140 extend along the first direction D1 (such as the vertical viewing direction) and are arranged at 90 degrees, so that the light on both sides of the horizontal viewing direction is concentrated toward the center, and a better left-right light collection effect is provided.

[0102] like Figure 1As shown, the switching control unit 130, the second light source unit 120 and the first light source unit 110 are sequentially arranged along the third direction D3, so that the switching control unit 130 is relatively close to the display panel 20, and the first light source unit 110 is relatively far away from the display panel 20. Specifically, the second light source unit 120 is arranged on the light emitting side 114a of the first light guide plate 114 of the first light source unit 110, and the switching control unit 130 is arranged on the light emitting side 124a of the second light guide plate 124 of the second light source unit 120, and the display panel 20 is located on the light emitting side 130a of the switching control unit 130. In this embodiment, the first prism sheet 140 is preferably arranged on the light emitting side 114a of the first light guide plate 114 and between the first light guide plate 114 and the second light guide plate 124, but is not limited thereto. In other embodiments, such as Figure 3 As shown, the first prism sheet 140 may be disposed on the light emitting side 124 a of the second light guide plate 124 and located between the second light guide plate 124 and the switching control unit 130 .

[0103] For later reference Figure 1A and Figure 1B , the light emission range of the backlight module 10 in the anti-peeping mode and the non-anti-peeping mode is described in detail. Figure 1A As shown, in the anti-peeping mode, the second light source 122 is in the off state, and the first light source 112 is in the on state, that is, the light emitting element 122a of the second light source 122 does not emit light, and only the light emitting element 112a of the first light source 112 emits the light L1. The light L1 of the first light source 112 is guided by the first light guide plate 114 and emitted toward the light emitting direction (for example, the third direction D3) and enters the first prism sheet 140. Due to the light collecting effect of the first prism sheet 140, the light L1 enters the switching control unit 130 in a more concentrated manner. In the anti-peeping mode, the switching control unit 130 is activated, and the light L1 of the first light source unit 110 passing through the first prism sheet 140 can be adjusted, so that the backlight module 10 has a more concentrated (narrow viewing angle) first light emitting range VA1.

[0104] like Figure 1BAs shown, in the non-peeping mode, the second light source 122 is in the on state, and the first light source 112 can be in the on state or the off state. In this embodiment, the first light source 112 is preferably in the on state to enhance the light output brightness of the backlight module 10. That is, the light emitting element 112a of the first light source 112 emits the light L1, and the light emitting element 122a of the second light source 122 emits the light L2. The light L1 of the first light source 112 is guided by the first light guide plate 114 and emitted in the light output direction (e.g., the third direction D3) and enters the first prism sheet 140. Due to the light collecting effect of the first prism sheet 140, the light L1 enters the switching control unit 130 in a more concentrated manner. The light L2 of the second light source 122 is guided by the second light guide plate 124 and emitted in the light output direction (e.g., the third direction D3) and enters the switching control unit 130. In the non-peeping mode, the switching control unit 130 is in an inactive state, and does not regulate the light L2 of the second light source unit 120 and the light L1 of the first light source unit 110 through the first prism sheet 140, so that the backlight module 10 has a more diffuse (wide viewing angle) second light emission range VA2. In other words, the second light emission range VA2 of the backlight module 10 is larger than the first light emission range VA1, which can be expressed as the viewing angle range in the non-peeping mode is larger than the viewing angle range in the peeping mode. In addition, in this embodiment, the second light emission range VA2 is composed of the light emitted by the first light source unit 110 and the second light source unit 120. When the first light source 112 is turned off, the second light emission range VA2 is only composed of the light emitted by the second light source unit 120.

[0105] According to practical applications, the backlight module of the present invention may further include other optical elements to enable the backlight module to have a desired optical effect. Figure 2 , Figure 2 FIG. 2 is a perspective view of a display device 2 and a backlight module 10A thereof according to a second embodiment of the present invention. In this embodiment, the display device 2 includes a display panel 20 and a backlight module 10A. Figure 1 The difference between the backlight module 10A and the backlight module 10A is that the backlight module 10A further includes a second prism sheet 150 to further enhance the central light intensity of the backlight module 10A. In one embodiment, the second prism sheet 150 is preferably disposed on the light emitting side 114a of the first light guide plate 114. Figure 2 As shown, the second prism sheet 150 is located at the light emitting side 124a of the second light guide plate 124 and between the second light guide plate 124 and the switching control unit 130, but is not limited thereto. Figure 4 and Figure 5 As shown, the second prism sheet 150 may be located between the first light guide plate 114 and the second light guide plate 124 .

[0106] The second prism sheet 150 has a plurality of second prism strips 152 extending along the second direction D2. Specifically, the plurality of second prism strips 152 are arranged along the first direction D1 and extend along the second direction D2 to provide a better optical effect. For example, the plurality of second prism strips 152 of the second prism sheet 150 extend along the second direction D2 (e.g., the horizontal viewing direction) and are arranged at 0 degrees to increase the central light intensity of the backlight module 10A.

[0107] like Figure 2 As shown, the backlight module 10A may further include a reflective layer 170 disposed on the opposite side of the light emitting side 114a of the first light guide plate 114. The reflective layer 170 may be used to reflect light toward the light emitting side 114a of the first light guide plate 114 to improve the utilization of light and thus increase the light emitting brightness of the backlight module 10A.

[0108] The backlight module 10A may further include one or more optical films (e.g., 162, 164) disposed on the light-emitting side 114a of the first light guide plate 114. One or more optical films (e.g., 162, 164) may be used to enhance the optical effect of the backlight module 10A, and are preferably disposed on the light-emitting side 124a of the second light guide plate 124, for example, between the second light guide plate 124 and the switching control unit 130. In one embodiment, the optical film may include an optical film 162, and the optical film 162 may be a diffuser for improving the uniformity of light. In this embodiment, the optical film 162 as a diffuser is disposed between the second light guide plate 124 and the switching control unit 130, and is preferably located between the second prism sheet 150 and the second light guide plate 124. In addition, the optical film may include an optical film 164 for improving brightness and visual effects. For example, the optical film 164 may be a reflective brightness enhancement film (DualBrightness Enhancement Film, DBEF), an advanced light control film (Advanced Light Control Film, ALCF), a diffuser, etc. In this embodiment, the optical film 164 is disposed between the second light guide plate 124 and the switching control unit 130, and is preferably located between the second prism sheet 150 and the switching control unit 130.

[0109] refer to Figure 3 , Figure 3 FIG. 2 is a perspective view of a display device 3 and a backlight module 10B thereof according to a third embodiment of the present invention. In this embodiment, the display device 3 includes a display panel 20 and a backlight module 10B. Figure 2The difference between the backlight module 10A and the backlight module 10B lies in the locations of the first prism sheet 140 and the second prism sheet 150. In this embodiment, the first prism sheet 140 is disposed on the light-emitting side 124a of the second light guide plate 124 and between the optical film 162 and the optical film 164. The second prism sheet 150 is disposed between the first light guide plate 114 and the second light guide plate 124. Thus, in the anti-peeping mode, the second light source 122 is turned off, the first light source 112 is turned on, and the switching control unit 130 is activated to still regulate the light of the first light source unit 110 through the first prism sheet 140, so that the backlight module 10B has a more concentrated light-emitting range with a narrow viewing angle.

[0110] refer to Figure 4 , Figure 4 FIG. 4 is a perspective view of a display device 4 and a backlight module 10C thereof according to a fourth embodiment of the present invention. In this embodiment, the display device 4 includes a display panel 20 and a backlight module 10C. Figure 1 The difference between the backlight module 10 and the backlight module 10C is that the backlight module 10C further includes a reflective layer 170, a second prism sheet 150 and an optical film 164. Figure 2 The reflective layer 170 is disposed on the opposite side of the light-emitting side 114a of the first light guide plate 114 and is used to reflect the light toward the light-emitting side 114a of the first light guide plate 114 to improve the utilization rate of the light. Figure 2 The same or similar. In this embodiment, the second prism sheet 150 is disposed on the light-emitting side 114a of the first light guide plate 114, and is located between the first light guide plate 114 and the second light guide plate 124. More specifically, the second prism sheet 150 is located between the first light guide plate 114 and the first prism sheet 140. That is, the first prism sheet 140 is closer to the second light guide plate 124 than the second prism sheet 150, and the second prism sheet 150 is closer to the first light guide plate 114 than the first prism sheet 140. The optical film 164 is disposed between the second light guide plate 124 and the switching control unit 130. Thereby, in the anti-peeping mode, the second light source 122 is turned off, the first light source 112 is turned on, and the switching control unit 130 is activated to still regulate the light of the first light source unit 110 through the second prism sheet 150 and the first prism sheet 140, so that the backlight module 10C has a more concentrated light-emitting range with a narrow viewing angle.

[0111] refer to Figure 5 , Figure 5 FIG. 5 is a perspective view of a display device 5 and a backlight module 10D thereof according to a fifth embodiment of the present invention. In this embodiment, the display device 5 includes a display panel 20 and a backlight module 10D. The backlight module 10D and Figure 4The difference of the backlight module 10C is the location of the first prism sheet 140 and the second prism sheet 150. In this embodiment, the second prism sheet 150 is disposed between the first light guide plate 114 and the second light guide plate 124 and is located between the first prism sheet 140 and the second light guide plate 124. That is, the first prism sheet 140 is closer to the first light guide plate 114 than the second prism sheet 150, and the second prism sheet 150 is closer to the second light guide plate 124 than the first prism sheet 140. Thus, in the anti-peeping mode, the second light source 122 is turned off, the first light source 112 is turned on, and the switching control unit 130 is activated to still regulate the light of the first light source unit 110 through the first prism sheet 140 and the second prism sheet 150, so that the backlight module 10D has a more concentrated light output range with a narrow viewing angle.

[0112] Figure 6 Schematic diagram of the brightness-angle distribution curve of a backlight module according to an embodiment of the present invention and a conventional backlight module in a non-privacy mode, wherein curve C1 is the brightness-angle distribution curve of a conventional backlight module using a privacy film, and curve C2 is the brightness-angle distribution curve of a backlight module (e.g., 10A) according to the present invention. Figure 6 As shown, in the non-peeping mode, the brightness-angle distribution curve (e.g., C1) of the existing backlight module is a multi-peak curve, which has significant peaks near the 0-degree viewing angle and the 60-degree viewing angle, respectively, so that the existing backlight module has a significant decrease in brightness between the viewing angles of 15 degrees to 30 degrees and between the viewing angles of -15 degrees to -60 degrees. In order to increase the brightness between the viewing angles of 15 degrees to 30 degrees and between the viewing angles of -15 degrees to -60 degrees, the existing backlight module usually needs to increase the power of the light source, which is not conducive to energy saving. Figure 6 As shown, in the non-peeping mode, the brightness-angle distribution curve (e.g., C2) of the backlight module of the present invention is a substantially smooth single-peak curve, which has a maximum brightness at approximately a viewing angle of 0 degrees, and gradually decreases in brightness toward a viewing angle of 60 degrees and a viewing angle of -60 degrees, thereby providing a more uniform brightness-viewing angle distribution and effectively improving energy consumption.

[0113] Fig. 7A Schematic diagram of the brightness-angle distribution curve of a backlight module of an embodiment of the present invention and a conventional backlight module in anti-peeping mode, wherein curve C1' is the brightness-angle distribution curve of the conventional backlight module using an anti-peeping film, and curve C2' is the brightness-angle distribution curve of the backlight module of the present invention (e.g., 10A). Fig. 7A As shown, in the anti-peeping mode, the brightness-angle distribution curve (e.g., C1') of the conventional backlight module is a curve with a wide peak, so that the conventional backlight module still has a significant brightness between the viewing angles of 15 degrees and 45 degrees, but has a poor anti-peeping effect. Fig. 7AAs shown, in the non-peeping mode, the brightness-angle distribution curve (e.g., C2') of the backlight module of the present invention is a curve with a narrower (or more concentrated) peak, and its brightness at a viewing angle of, for example, 15 degrees to 45 degrees is significantly lower than that of the existing backlight module, and has a better anti-peeping effect. Figure 7B , which is Fig. 7A The brightness-angle distribution curve (e.g. C1' and C2') of the embodiment is a partial enlarged view at a viewing angle of -30 degrees to -60 degrees. Figure 7B As shown, the backlight module of the present invention has lower brightness than the existing backlight module in the range of -30 degree to -60 degree viewing angle, so that the anti-peeping effect of the backlight module of the present invention is better than that of the existing backlight module.

[0114] In one embodiment, the brightness ratio of the first light source 112 to the second light source 122 is preferably 2:1. Thus, in the non-peeping mode, the backlight module (e.g., 10A) of the present invention can achieve a brightness of about 50% at a 45-degree viewing angle, but the present invention is not limited thereto. Depending on the actual application, the first light source 112 and the second light source 122 can have any appropriate brightness ratio.

[0115] Furthermore, by locally controlling the second light source 122 and the switching control unit 130, the backlight module of the present invention can effectively provide a local anti-peeping effect. Figure 8 , Figure 8 1 is a three-dimensional schematic diagram of a display device 6 and a backlight module 10E thereof according to a sixth embodiment of the present invention. In this embodiment, the display device 6 includes a display panel 20 and a backlight module 10E. The backlight module 10E has a similar structure to the backlight module 10A, and the difference lies in the design of the second light source 122 and the switching control unit 130. Specifically, the switching control unit 130 has a first control area 132 and a second control area 134, and the second light source 122 includes a first sub-light source 1221 and a second sub-light source 1222. The first sub-light source 1221 and the second sub-light source 1222 correspond to the first control area 132 and the second control area 134, respectively. For example, a plurality of light-emitting elements (e.g., 122a) of the second light source 122 can be grouped into a first sub-light source 1221 and a second sub-light source 1222 to independently control the on / off state of the first sub-light source 1221 and the second sub-light source 1222. Similarly, the switching control unit 130 can also independently control the activation or deactivation of the first control area 132 and the second control area 134 .

[0116] refer to Figure 8A-1 and Figure 8A-2 , Figure 8A-1 and Figure 8A-2 Schematic diagram of the light emission range of the display device 6 and its backlight module 10E in different local anti-peeping modes. Figure 8A-1As shown, in the local anti-peeping mode, the first light source 112 is turned on, and the first sub-light source 1221 is selectively turned on or off (at Figure 8A-1 is turned on), and the second sub-light source 1222 is turned off, the switching control unit 130 turns off the first control area 132 and turns on the second control area 134, so that the backlight module 10E has a non-peeping light emitting range (for example, the third light emitting range VA3) substantially corresponding to the first control area 132 and an anti-peeping light emitting range (for example, the fourth light emitting range VA4) substantially corresponding to the second control area 134, wherein the anti-peeping light emitting range is smaller than the non-peeping light emitting range, for example, the viewing angle range of the fourth light emitting range VA4 is smaller than the viewing angle range of the third light emitting range VA3. Specifically, at Figure 8A-1 In the embodiment of the present invention, in the partial anti-peeping mode, the first light source 112 is turned on to emit the light L1, the first sub-light source 1221 of the second light source 122 can be turned on or off, and the second sub-light source 1222 is turned off. In this embodiment, the first sub-light source 1221 is preferably turned on to increase the viewing angle range of the non-peeping area (e.g., the portion corresponding to the first control area 132) (e.g., to increase the third light emitting range VA3). The light L1 of the first light source 112 is guided by the first light guide plate 114 and emitted toward the light emitting direction (e.g., the third direction D3) and enters the first prism sheet 140. Due to the light collecting effect of the first prism sheet 140, the light L1 is more concentratedly entered into the switching control unit 130 through the optical film 162 and the second prism sheet 150. In the partial anti-peeping mode, the light L2 of the first sub-light source 1221 enters the switching control unit 130 through the optical film 162 and the second prism sheet 150. The switching control unit 130 turns off the first control area 132 and activates the second control area 134, so that the light L1 and L2 traveling toward the first control area 132 pass through the first control area 132 substantially without control, so as to form a non-peep-proof light-emitting range (e.g., the third light-emitting range VA3) substantially corresponding to the first control area 132, and its viewing angle range is relatively large (or wide). At the same time, the light L1 and L2 traveling toward the second control area 134 are controlled by the second control area 134 to form an anti-peep-proof light-emitting range (e.g., the fourth light-emitting range VA4) substantially corresponding to the second control area 134, and its viewing angle range is relatively small (or narrow) due to the control. Thereby, the non-peeping light emitting range (for example, the third light emitting range VA3) of the backlight module 10E substantially corresponds to the first control area 132, and the anti-peeping light emitting range (for example, the fourth light emitting range VA4) of the backlight module 10E substantially corresponds to the second control area 134, that is, the backlight module 10E has a local shared (local non-peeping light emitting effect) with a relatively wide viewing angle biased to one side (for example, the first control area 132 side) and a local anti-peeping light emitting effect with a relatively narrow viewing angle biased to the other side (for example, the second control area 134 side), but is not limited to this.

[0117] In the above embodiment, the first sub-light source 1221 is preferably turned on to increase the viewing angle range of the non-peep-proof area, but the present invention is not limited thereto. When the light luminance of the first light source 112 is sufficient to meet the light luminance requirement, the first sub-light source 1221 can be turned off. Figure 8A-2 As shown, in the partial privacy protection mode, the first light source 112 can be in an on state to emit light L1, and the first sub-light source 1221 and the second sub-light source 1222 of the second light source 122 are in an off state. The light L1 of the first light source 112 is guided by the first light guide plate 114 and emitted toward the light emitting direction (e.g., the third direction D3) and enters the first prism sheet 140. Through the light collecting effect of the first prism sheet 140, the light L1 is more concentratedly entered into the switching control unit 130 through the optical film 162 and the second prism sheet 150. In the partial privacy protection mode, the switching control unit 130 turns off the first control area 132 and turns on the second control area 134, so that the light L1 traveling toward the first control area 132 passes through the first control area 132 substantially without being regulated, so as to form a non-privacy protection light emitting range (e.g., the third light emitting range VA3') substantially corresponding to the first control area 132, and its viewing angle range is relatively large (or wider). At the same time, the light L1 toward the second control area 134 is regulated by the second control area 134 to form an anti-peeping light emitting range (e.g., the fourth light emitting range VA4') substantially corresponding to the second control area 134, and its viewing angle range is relatively small (or narrow) due to the regulation. Thereby, the non-anti-peeping light emitting range (e.g., the third light emitting range VA3') of the backlight module 10E substantially corresponds to the first control area 132, and the anti-peeping light emitting range (e.g., the fourth light emitting range VA4') of the backlight module 10E substantially corresponds to the second control area 134, that is, the backlight module 10E has a display effect of partial sharing (partial non-peeping) with a relatively wide viewing angle biased to one side (e.g., the first control area 132 side) and partial anti-peeping with a relatively narrow viewing angle biased to the other side (e.g., the second control area 134 side), but is not limited thereto.

[0118] At Figure 8A-1 and Figure 8A-2 In the embodiment, in order to illustrate the relative size of the viewing angle range, although the third light emitting range VA3 (or VA3') and the fourth light emitting range VA4 (or VA4') are not overlapped, in actual operation, the third light emitting range VA3 (or VA3') and the fourth light emitting range VA4 (or VA4') can partially overlap, and the third light emitting range VA3 (or VA3') and the fourth light emitting range VA4 (or VA4') constitute the overall light emitting range of the backlight module 10E in the local anti-peep mode, wherein the portion corresponding to the first control area 132 has a wider viewing angle, and the portion corresponding to the second control area 134 has a narrower viewing angle. Furthermore, in Figure 8A-1 In the embodiment of the present invention, since the first sub-light source 1221 is turned on, Figure 8A-1The third light emitting range VA3 is relatively larger than Figure 8A-2 The first sub-light source 1221 is in the third light emitting range VA3' in the off state, that is, Figure 8A-1 The viewing angle range of the non-privacy protection area (eg, the portion corresponding to the first control area 132) is greater than Figure 8A-2 The viewing angle range of the non-peep-proof area (eg, the portion corresponding to the first control area 132).

[0119] In another local anti-peeping mode (not shown), by controlling the first light source 112 to be turned on, the first sub-light source 1221 to be turned off, and the second sub-light source 1222 to be selectively turned on or off, the switching control unit 130 activates the first control area 132 and turns off the second control area 134, so that the non-anti-peeping light emitting range of the backlight module 10E (for example, the third light emitting range VA3) substantially corresponds to the second control area 134, and the anti-peeping light emitting range of the backlight module 10E (for example, the fourth light emitting range VA4) substantially corresponds to the first control area 132.

[0120] also, Figure 8 The display device 6 and its backlight module 10E can also have light emission ranges in anti-peeping mode and non-anti-peeping mode according to the control method of the above-mentioned embodiment. Figure 8B As shown, in the anti-peeping mode, the first sub-light source 1221 and the second sub-light source 1222 of the second light source 122 are both in the off state, and the first light source 112 is in the on state. The light L1 of the first light source 112 is guided by the first light guide plate 114 and emitted toward the light emitting direction (for example, the third direction D3) and enters the first prism sheet 140. Due to the light collecting effect of the first prism sheet 140, the light L1 enters the switching control unit 130 in a more concentrated manner. In the anti-peeping mode, the switching control unit 130 controls the first control area 132 and the second control area 134 to be activated, and the light L1 of the first light source unit 110 passing through the first prism sheet 140 can be adjusted, so that the backlight module 10E has a more concentrated (narrow viewing angle) first light emitting range VA1.

[0121] like Figure 8CAs shown, in the non-peeping mode, the first sub-light source 1221 and the second sub-light source 1222 of the second light source 122 are both in the on state, and the first light source 112 can be in the on state or the off state. In this embodiment, the first light source 112 is preferably in the on state to increase the light output brightness of the backlight module 10E. The light L1 of the first light source 112 is guided by the first light guide plate 114 and emitted toward the light output direction (for example, the third direction D3) and enters the first prism sheet 140. Due to the light collecting effect of the first prism sheet 140, the light L1 enters the switching control unit 130 more concentratedly. The light L2 of the second light source 122 is guided by the second light guide plate 124 and emitted toward the light output direction (for example, the third direction D3) and enters the switching control unit 130. In the non-peeping mode, the switching control unit 130 is in an inactive state and does not regulate the light L2 of the second light source unit 120 and the light L1 of the first light source unit 110 passing through the first prism film 140, so that the backlight module 10E has a more diffuse (wide viewing angle) second light output range VA2.

[0122] refer to Fig.9A and Fig. 9B , Fig.9A is a schematic diagram of a switching control unit 130 according to an embodiment of the present invention, and Fig. 9B for Fig.9A Schematic diagram of the alignment of some components (such as polarizers and alignment layers) of the switching control unit 130. Fig.9A and Fig. 9B As shown, the switching control unit 130 may be a viewing angle control (VAC) unit. In one embodiment, the switching control unit 130 is preferably a liquid crystal viewing angle control unit, such as a dual liquid crystal viewing angle control unit, which includes a first polarizer 132a, a first substrate 134a, a first electrode 136a, a first alignment layer 138a, a first liquid crystal layer 135a, a second alignment layer 138b, a second electrode 136b, a second substrate 134b, a second polarizer 132b, a third substrate 134c, a third electrode 136c, a third alignment layer 138c, a second liquid crystal layer 135b, a fourth alignment layer 138d, a fourth electrode 136d, a fourth substrate 134d and a third polarizer 132c in sequence along the light emitting direction (e.g., the first direction D3). In one embodiment, the first substrate 134a, the second substrate 134b, the third substrate 134c and the fourth substrate 134d are preferably transparent substrates, such as glass substrates, but are not limited thereto. In other embodiments, the first substrate 134 a , the second substrate 134 b , the third substrate 134 c , and the fourth substrate 134 d may be polymer substrates.

[0123] like Fig. 9BAs shown, in this embodiment, the polarization angle of the first polarizer 132a is preferably 115 degrees, the polarization angle of the second polarizer 132b is preferably 205 degrees, and the polarization angle of the third polarizer 132c is preferably 90 degrees. The first electrode 136a, the second electrode 136b, the third electrode 136c and the fourth electrode 136d are preferably electrodes made of light-transmitting materials, such as indium tin oxide (ITO) electrodes. The alignment angle of the first alignment layer 138a is preferably 115 degrees, the alignment angle of the second alignment layer 138b is preferably 205 degrees, the alignment angle of the third alignment layer 138c is preferably 115 degrees, and the alignment angle of the fourth alignment layer 138d is preferably 180 degrees. Thus, in the anti-peeping mode, a voltage is applied so that the switching control unit 130 is turned on and has the function of regulating the light viewing angle; in the non-anti-peeping mode, no voltage is applied so that the switching control unit 130 is turned off and does not have the function of regulating the light viewing angle. In the local anti-peeping mode, a voltage is applied to a part of the control area of ​​the switching control unit 130 (for example, one of the first control area 132 and the second control area 134) to turn it on and have the function of regulating the light viewing angle, and no voltage is applied to another part of the control area of ​​the switching control unit 130 (for example, the other of the first control area 132 and the second control area 134) to turn it off and not have the function of regulating the light viewing angle, so as to make the light emitting range of the control area corresponding to the applied voltage relatively narrow (or the viewing angle range is relatively small), thereby effectively achieving the effect of local anti-peeping.

[0124] It should be noted here that in the local privacy protection mode, the number of control areas of the switching control unit 130 preferably corresponds to the number of sub-light sources of the second light source 122, and can be designed to be more than two according to actual applications, so as to achieve a local privacy protection effect in multiple areas.

[0125] The present invention has been described by the above-mentioned relevant embodiments, however, the above-mentioned embodiments are only examples for implementing the present invention. It must be pointed out that the disclosed embodiments do not limit the scope of the present invention. On the contrary, modifications and equivalent settings included in the spirit and scope of the claims are all included in the scope of the present invention.

Claims

1. A backlight module, characterized in that: Include: Switching control unit; A first light source unit, located below the switching control unit and comprising a first light source and a first light guide plate; A second light source unit is located between the switching control unit and the first light source unit and includes a second light source and a second light guide plate; as well as A first prism sheet is disposed on the light-emitting side of the first light guide plate, In an anti-peeping mode, the second light source is turned off, the first light source is turned on, and the switching control unit is activated to regulate the light of the first light source unit passing through the first prism sheet so that the backlight module has a first light emitting range; In a non-peeping mode, the second light source is turned on and the switching control unit is turned off, so that the backlight module has a second light emitting range, and the second light emitting range is larger than the first light emitting range.

2. The backlight module according to claim 1, wherein: In the non-peeping mode, the first light source is turned on, and the second light output range is formed by the light output of the first light source unit and the second light source unit.

3. The backlight module according to claim 1, wherein: The first prism sheet has a plurality of first prism strips extending along a first direction.

4. The backlight module according to claim 3, wherein: The invention further comprises a second prism sheet, wherein the second prism sheet has a plurality of second prism strips extending along a second direction, and the second direction is substantially perpendicular to the first direction.

5. The backlight module according to claim 4, wherein: The second prism sheet is arranged on the light-emitting side of the first light guide plate and is located between the first light guide plate and the second light guide plate.

6. The backlight module according to claim 4, wherein: The second prism sheet is arranged on the light emitting side of the second light guide plate.

7. The backlight module according to claim 1, wherein: It further comprises a reflective layer disposed on the opposite side of the light emitting side of the first light guide plate.

8. The backlight module according to claim 1, wherein: It further comprises an optical film, which is arranged on the light emitting side of the first light guide plate.

9. The backlight module according to claim 1, wherein: The second light source includes a first sub-light source and a second sub-light source, and the switching control unit includes a first control area and a second control area, which correspond to the first sub-light source and the second sub-light source respectively. In a local anti-peep mode, the first light source is turned on, the first sub-light source is selectively turned on or off, and the second sub-light source is turned off. The switching control unit turns off the first control area and starts the second control area so that the backlight module has a third light emitting range and a fourth light emitting range, wherein the third light emitting range substantially corresponds to the first control area, the fourth light emitting range substantially corresponds to the second control area, and the fourth light emitting range is smaller than the third light emitting range.

10. The backlight module according to claim 9, wherein: In the local anti-peeping mode, the first sub-light source is turned on to increase the third light emitting range.

11. The backlight module according to claim 1, wherein: The brightness ratio of the first light source to the second light source is 2:

1.

12. A backlight module, characterized in that: Include: A switching control unit having a first control area and a second control area; A first light source unit, located below the switching control unit and comprising a first light source and a first light guide plate; A second light source unit is located between the switching control unit and the first light source unit and includes a second light source and a second light guide plate, wherein the second light source includes a first sub-light source and a second sub-light source corresponding to the first control area and the second control area respectively; and A first prism sheet is disposed on the light-emitting side of the first light guide plate, In a local anti-peeping mode, the first light source is turned on, the first sub-light source is selectively turned on or off, and the second sub-light source is turned off, the switching control unit turns off the first control area and starts the second control area, so that the backlight module has a non-anti-peeping light-emitting range that substantially corresponds to the first control area and an anti-peeping light-emitting range that substantially corresponds to the second control area, and the anti-peeping light-emitting range is smaller than the non-anti-peeping light-emitting range.

13. The backlight module according to claim 12, wherein: The first prism sheet has a plurality of first prism strips extending along a first direction.

14. The backlight module according to claim 13, wherein: The invention further comprises a second prism sheet, wherein the second prism sheet has a plurality of second prism strips extending along a second direction, and the second direction is substantially perpendicular to the first direction.

15. The backlight module according to claim 14, wherein: The second prism sheet is arranged on the light-emitting side of the first light guide plate and is located between the first light guide plate and the second light guide plate.

16. The backlight module according to claim 14, wherein: The second prism sheet is arranged on the light emitting side of the second light guide plate.

17. The backlight module according to claim 12, wherein: It further comprises a reflective layer disposed on the opposite side of the light emitting side of the first light guide plate.

18. The backlight module according to claim 12, wherein: It further comprises an optical film, which is arranged on the light emitting side of the first light guide plate.

19. The backlight module according to claim 12, wherein: In the local anti-peeping mode, the first sub-light source is turned on to increase the non-anti-peeping light emitting range.

20. A display device, characterized in that: Include: A display panel having a display surface; and The backlight module as claimed in any one of claims 1 to 19, is arranged on the opposite side of the display surface of the display panel.

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