Switchable privacy display device and method of controlling the same

Abstract

A switchable privacy display device includes a backlight module, a louver film, a light control film, a switching panel, a first polarizer, a display panel, and a second polarizer stacked in sequence along a stacking direction. The louver film includes light-shielding portions extending along an extending direction perpendicular to the stacking direction. The switching panel includes a first substrate, a second substrate, a liquid crystal layer between the first substrate and the second substrate, a first electrode and a second electrode between the first substrate and the liquid crystal layer, a first alignment layer between the first electrode and the liquid crystal layer, and a second alignment layer between the liquid crystal layer and the second substrate. An optical absorption axis of the light control film is parallel to the stacking direction, and an alignment direction of the second alignment layer is the same as an optical absorption axis of the second polarizer and perpendicular to the stacking direction.

Description

Technical Field

[0001] This invention relates to a switchable privacy display device and its control method, and more particularly to a display device including a switching panel and its control method. Background Technology

[0002] Generally, display devices typically offer wide viewing angles. However, in certain situations or contexts, such as when users browse private websites, access confidential information, or enter passwords in public, wide viewing angles can make the screen vulnerable to peeping and leaks of confidential information. Therefore, modern display devices offer different viewing modes, such as a wide-viewing-angle sharing mode and a narrow-viewing-angle privacy mode. However, current display devices cannot simultaneously achieve privacy protection or sharing modes for both horizontal and vertical viewing angles. Summary of the Invention

[0003] This invention provides a switchable privacy display device and its control method, which can achieve simultaneous privacy protection or simultaneous sharing from both the left and right and top and bottom perspectives.

[0004] The switchable privacy display device proposed in at least one embodiment of the present invention includes a backlight module, a switching panel, a venetian blind film, a light control film, a first polarizer, a display panel, and a second polarizer. The switching panel is disposed on the backlight module along a stacking direction and includes a first substrate, a second substrate, a liquid crystal layer, a first electrode, a second electrode, a first alignment layer, and a second alignment layer. The liquid crystal layer is disposed between the first substrate and the second substrate; the first electrode is disposed between the first substrate and the liquid crystal layer; the second electrode is disposed between the first substrate and the liquid crystal layer and is electrically insulated from the first electrode; the first alignment layer is disposed between the first electrode and the liquid crystal layer and has a first alignment direction; and the second alignment layer is disposed between the liquid crystal layer and the second substrate and has a second alignment direction. The venetian blind film includes a plurality of light-shielding portions extending along an extension direction perpendicular to the stacking direction. In the stacking direction, the venetian blind film and the light control film are disposed between the backlight module and the switching panel, and the light absorption axis of the light control film is parallel to the stacking direction. The first substrate, the second substrate, the first polarizer, the display panel, and the second polarizer are stacked sequentially along the stacking direction, and the second alignment direction is the same as the light absorption axis of the second polarizer and perpendicular to the stacking direction.

[0005] In at least one embodiment of the present invention, the first alignment direction is the same as the second alignment direction.

[0006] In at least one embodiment of the present invention, the first alignment direction is parallel to the stacking direction.

[0007] In at least one embodiment of the present invention, the light absorption axis of the first polarizer is perpendicular to the stacking direction and the light absorption axis of the second polarizer.

[0008] In at least one embodiment of the present invention, the venetian blind film further includes a plurality of light-transmitting portions extending along the extending direction, the light-transmitting portions and the plurality of light-blocking portions being arranged alternately along the arrangement direction, and the arrangement direction being parallel to the light absorption axis of the first polarizer.

[0009] In at least one embodiment of the present invention, the switching panel further includes an insulating layer disposed on the first substrate and located between the first electrode and the second electrode.

[0010] In at least one embodiment of the present invention, the first electrode comprises a plurality of first sub-electrodes arranged at intervals.

[0011] In at least one embodiment of the present invention, the second electrode includes a plurality of second sub-electrodes arranged at intervals, and these second sub-electrodes are alternately arranged with the plurality of first sub-electrodes.

[0012] In at least one embodiment of the present invention, the liquid crystal layer comprises positive liquid crystal.

[0013] The control method for switching a switchable privacy display device to privacy mode and sharing mode according to at least another embodiment of the present invention includes the following steps: Providing the switchable privacy display device; Setting the voltage difference between the first electrode and the second electrode to 0 to switch the switchable privacy display device to privacy mode; Setting the voltage difference between the first electrode and the second electrode to non-zero to switch the switchable privacy display device to sharing mode. Attached Figure Description

[0014] Figure 1A This is a cross-sectional schematic diagram of a switchable privacy display device according to at least one embodiment of the present invention.

[0015] Figure 1B This is a cross-sectional schematic diagram of a switchable privacy display device according to at least another embodiment of the present invention.

[0016] Figure 2 This is a partial cross-sectional schematic diagram of a venetian blind film according to at least one embodiment of the present invention.

[0017] Figure 3 This is a partial top view of the switching panel according to at least one embodiment of the present invention.

[0018] Figure 4 This is a partial top view of the switching panel according to at least another embodiment of the present invention.

[0019] Figure 5A and Figure 5B These are cross-sectional schematic diagrams of a switchable privacy display device according to at least another embodiment of the present invention.

[0020] Figure 6A and Figure 6B These are schematic diagrams showing the light output brightness of the switching panel of at least one embodiment of the present invention applied to privacy mode and sharing mode from various angles.

[0021] The annotations in the attached figures are explained as follows: 10, 10', 11, 11': Switchable privacy display device 100: Backlight Module 200: Venetian blind film 202:Light shielding part 204: Translucent Part 300: Light control film 400, 400A: Switching panel 402: First substrate 404: Second substrate 406: Liquid Crystal Layer 408: First electrode 410, 410A: Second electrode 412: First alignment layer 414: Second alignment layer 416: Insulation layer 500: First polarizer 600: Display panel 700: Second polarizer A1, A2, A3: Light absorption axes D1: First Direction D2: Second Direction D3: Third direction M1, M2: Light output brightness distribution P1: First sub-electrode P2: Second sub-electrode R1, R1': First alignment direction R2: Second alignment direction. Detailed Implementation

[0022] In the following text, to clearly present the technical features of the present invention, the dimensions (e.g., length, width, thickness, and depth) of the elements (e.g., layers, films, substrates, and regions) in the accompanying drawings will be enlarged proportionally, and the number of some elements may be reduced. Therefore, the description and explanation of the embodiments below are not limited to the number of elements in the drawings or the size and shape of the elements, but should cover the dimensions, shapes, and deviations from both caused by actual manufacturing processes and / or tolerances. For example, a flat surface shown in the drawings may have rough and / or non-linear characteristics, and an acute angle shown in the drawings may be rounded. Therefore, the elements presented in the accompanying drawings of the present invention are mainly for illustration and are not intended to accurately depict the actual shape of the elements, nor are they intended to limit the scope of the claims of the present invention.

[0023] Secondly, the terms "approximately," "about," or "substantially" used in this invention not only cover explicitly stated numerical values ​​and ranges, but also the permissible deviation range understandable to those skilled in the art to which this invention pertains. This deviation range can be determined by errors generated during measurement, which may arise from limitations of either the measurement system or the process conditions. For example, two objects (e.g., planes or traces of a substrate) are "substantially parallel" or "substantially perpendicular," where "substantially parallel" and "substantially perpendicular" respectively represent that the parallelism and perpendicularity between the two objects can include non-parallelism and non-perpendicularity caused by permissible deviation ranges.

[0024] The spatial relative terms used in this invention, such as "below," "under," "above," and "above," are for the convenience of describing the relative relationship between one element or feature and another, as illustrated in the figures. The true meaning of these spatial relative terms includes other orientations. For example, when the illustration is rotated 180 degrees vertically, the relationship between one element and another may change from "below" or "under" to "above" or "above." Furthermore, the spatial relative descriptions used in this invention should be interpreted in the same way.

[0025] It should be understood that although the present invention may use terms such as "first," "second," and "third" to describe various elements or signals, these elements or signals should not be limited by these terms. These terms are primarily used to distinguish one element from another, or one signal from another. Furthermore, the term "or" as used in this invention may, depending on the specific circumstances, include any combination of one or more of the associated listed items.

[0026] Furthermore, the present invention can be implemented or applied through other different specific embodiments, and the details of the present invention can also be combined, modified and changed in various embodiments based on different viewpoints and applications without departing from the concept of the present invention.

[0027] Figure 1A This is a cross-sectional schematic diagram of a switchable privacy display device 10 according to at least one embodiment of the present invention. Figure 1B This is a cross-sectional schematic diagram of a switchable privacy display device 11 according to at least another embodiment of the present invention. Please refer to... Figure 1A and Figure 1B The switchable privacy display device 10 includes a backlight module 100, a venetian blind diaphragm 200, a light control diaphragm 300, a switching panel 400, a first polarizer 500, a display panel 600, and a second polarizer 700. The switching panel 400 is disposed on the backlight module 100 along the stacking direction (first direction D1). In the stacking direction (first direction D1), the venetian blind diaphragm 200 and the light control diaphragm 300 are disposed between the backlight module 100 and the switching panel 400, and the light absorption axis A1 of the light control diaphragm 300 is substantially parallel to the stacking direction (first direction D1).

[0028] In some embodiments, such as Figure 1A As shown, in the stacking direction (first direction D1), a venetian blind diaphragm 200 is disposed on the backlight module 100, a light control diaphragm 300 is disposed on the venetian blind diaphragm 200, and a switching panel 400 is disposed on the light control diaphragm 300. In other embodiments, such as Figure 1B As shown, the light control film 300 is disposed on the backlight module 100, the venetian blind film 200 is disposed on the light control film 300, and the switching panel 400 is disposed on the venetian blind film 200.

[0029] Figure 2 This is a partial cross-sectional schematic diagram of the venetian blind membrane 200 according to at least one embodiment of the present invention. Please refer to... Figure 1A , Figure 1B and Figure 2 The venetian blind 200 includes a plurality of light-blocking portions 202 and a plurality of light-transmitting portions 204 extending along an extension direction (second direction D2). The light-transmitting portions 204 and the light-blocking portions 202 are substantially staggered along an arrangement direction (third direction D3), and the arrangement direction (third direction D3) is substantially parallel to the light absorption axis A2 of the first polarizer 500.

[0030] Figure 3 This is a partial top view of a switching panel 400 according to at least one embodiment of the present invention. Please refer to... Figure 1A , Figure 1B and Figure 3The switching panel 400 includes a first substrate 402, a second substrate 404, a liquid crystal layer 406, a first electrode 408, a second electrode 410, a first alignment layer 412, and a second alignment layer 414. The liquid crystal layer 406 is disposed between the first substrate 402 and the second substrate 404, the first electrode 408 is disposed between the first substrate 402 and the liquid crystal layer 406, and the second electrode 410 is disposed between the first substrate 402 and the liquid crystal layer 406 and is electrically insulated from the first electrode 408.

[0031] The first alignment layer 412 is disposed between the first electrode 408 and the liquid crystal layer 406 and has a first alignment direction R1. The second alignment layer 414 is disposed between the liquid crystal layer 406 and the second substrate 404 and has a second alignment direction R2. The first substrate 402, the second substrate 404, the first polarizer 500, the display panel 600, and the second polarizer 700 are substantially stacked sequentially along the stacking direction (first direction D1), and the second alignment direction R2 is substantially the same as and perpendicular to the light absorption axis A3 of the second polarizer 700 and perpendicular to the stacking direction (first direction D1). That is, the second alignment direction R2 and the light absorption axis A3 of the second polarizer 700 are substantially parallel to the extension direction of the light-shielding portion 202 of the venetian blind film 200 (second direction D2), and the first alignment direction R1 and the second alignment direction R2 are formed, for example, by using a friction alignment method.

[0032] By using a switching panel 400 with the second alignment direction R2 of the second alignment layer 414 substantially the same as the light absorption axis A3 of the second polarizer 700 and perpendicular to the stacking direction (first direction D1), and in conjunction with a venetian blind film 200, the switchable privacy display device 10 can achieve a mode that simultaneously protects against peeping from the left and right views as well as from the up and down views, or allows for simultaneous sharing.

[0033] Please continue reading. Figure 1A and Figure 1B The first alignment direction R1 of the first alignment layer 412 is substantially the same as the second alignment direction R2 of the second alignment layer 414, that is, both the first alignment direction R1 and the second alignment direction R2 are horizontal alignments that are substantially parallel to the second direction D2. The light absorption axis A2 of the first polarizer 500 is substantially perpendicular to the stacking direction (first direction D1) and the light absorption axis A3 of the second polarizer 700.

[0034] Please continue reading. Figure 3 The switching panel 400 further includes an insulating layer 416 disposed on the first substrate 402 and located between the first electrode 408 and the second electrode 410. The first electrode 408 includes a plurality of first sub-electrodes P1 arranged at intervals. Each first sub-electrode P1 extends along a second direction D2, for example. The plurality of first sub-electrodes P1 are arranged at intervals along a third direction D3, for example.

[0035] Figure 4 This is a partial top view of a switching panel 400A according to at least another embodiment of the present invention. Please refer to... Figure 4 , Figure 4 Implementation examples and Figure 3 Most of the components in the embodiments have the same structure and relative positional relationship, and Figure 4 Switching panel 400A and Figure 3 The 400 switching panel can be applied to Figure 1A and Figure 1B The same technical features are not described again here in the switchable privacy display devices 10 and 11. Figure 4 Implementation examples and Figure 3 The main differences in the embodiments are Figure 4 The second electrode 410A and the first electrode 408 of the switching panel 400A are both disposed on the insulating layer 416. In other embodiments, the insulating layer 416 may be omitted.

[0036] In detail, such as Figure 4 As shown, the first electrode 408 includes a plurality of first sub-electrodes P1 arranged at intervals, and the second electrode 410A includes a plurality of second sub-electrodes P2 arranged at intervals, with the second sub-electrodes P2 and the first sub-electrodes P1 arranged alternately. Each first sub-electrode P1 extends, for example, along a second direction D2. Each second sub-electrode P2 extends, for example, along a second direction D2. The plurality of first sub-electrodes P1 and the plurality of second sub-electrodes P2 are, for example, arranged alternately along a third direction D3.

[0037] Figure 5A and Figure 5B These are schematic cross-sectional views of switchable privacy display devices 10' and 11', respectively, according to at least another embodiment of the present invention. Please refer to... Figure 5A and Figure 5B , Figure 5A and Figure 5B Implementation examples and Figure 1A and Figure 1B Most of the components in the embodiments have the same structure and relative positional relationship, and Figure 4 Switching panel 400A and Figure 3 The 400 switching panel can also be applied to Figure 5A and Figure 5B The same technical features are not described again here in the switchable privacy display devices 10' and 11'. Figure 5A and Figure 5B Implementation examples and Figure 1A and Figure 1B The main differences in the embodiments are Figure 5A and Figure 5BThe first alignment direction R1' of the first alignment layer 412 of the switchable privacy display devices 10' and 11' is parallel to the stacking direction (first direction D1), that is, the first alignment direction R1 is vertical alignment, while the second alignment direction R2 is horizontal alignment. By means of the aforementioned alignment design, the light emission uniformity of the switchable privacy display devices 10' and 11' in the sharing mode can be improved.

[0038] In some embodiments, the display panel 600 is, for example, a liquid crystal display panel, which may include a pixel array substrate (not shown), a counter substrate (not shown) disposed opposite to the pixel array substrate, and a display liquid crystal layer (not shown) located between the pixel array substrate and the counter substrate. The display panel 600 is used to display images. The backlight module 100 is not, for example, a collimated backlight module, but a general backlight module with uniform light pattern.

[0039] In some embodiments, the switching panel 400 may be of the fringe field switching (FFS) type or the in-plane switching (IPS) type. In some embodiments, the first substrate 402 and the second substrate 404 are light-transmitting substrates, and the material of the light-transmitting substrate may be glass, quartz, organic polymer, or other suitable materials. The first electrode 408 and the second electrodes 410, 410A are light-transmitting electrodes, and the material of the light-transmitting electrodes may be metal oxides, such as indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, indium germanium zinc oxide, other suitable oxides, or a stacked layer of at least two of the above. The material of the first alignment layer 412 and the second alignment layer 414 may be polyimide, polyamic acid (PAA), or other suitable materials. The liquid crystal layer 406 contains positive liquid crystal. The switching panel 400 is used to change the direction of light, not to display images.

[0040] Figure 6A This is a schematic diagram showing the light output brightness of the switching panel 400 in privacy mode according to at least one embodiment of the present invention. Please refer to... Figure 6A When the driving circuit (not shown) of the switching panel 400 makes the voltage difference between the first electrode 408 and the second electrode 410 zero, the light beam passes sequentially through the light control diaphragm 300 and the switching panel 400, and the output brightness at each viewing angle is as follows: Figure 6A As shown in the light output brightness distribution M1, the center and left and right sides have higher light output brightness, while the top and bottom sides have lower light output brightness.

[0041] Therefore, by using the venetian blind film 200 located between the backlight module 100 and the switching panel 400, the left and right side light beams from the backlight module 100 can be absorbed, and by using the light control film 300 located between the venetian blind film 200 and the switching panel 400, the upper and lower side light beams from the backlight module 100 can be absorbed, so as to achieve a mode that simultaneously prevents peeping from the left and right and upper and lower viewing angles.

[0042] In detail, with Figure 1A and Figure 5A For example, the light beam from the backlight module 100 is absorbed on the left and right sides after passing through the venetian blind diaphragm 200. The light beams from the top and bottom sides of the venetian blind diaphragm 200, when passing through the light control diaphragm 300 with its light absorption axis A1 parallel to the first direction D1, will have their linearly polarized beams in the second direction D2 (where azimuth angles are 90 degrees and 270 degrees) absorbed at increasingly larger angles. This results in only the beam in the positive viewing angle direction and the linearly polarized beam in the third direction D3. This absorption occurs when the beam passes through the disabled switching panel 400 (i.e., the first electrode 408 and...). After the voltage difference between the second electrodes 410 and 410A is 0, the polarization state of the light beam remains unchanged and still only has a linear polarization state in the positive viewing direction and in the third direction D3. When the light beam from the disabled switching panel 400, which only has a positive viewing direction and a linear polarization state in the third direction D3, passes through the first polarizer 500 with a light absorption axis A2 parallel to the third direction D3, the linear polarization state of the light beam in the third direction D3 will be absorbed by the first polarizer 500. Therefore, the privacy protection effect can be achieved simultaneously in the third direction D3 (i.e., the left and right viewing angle) and the second direction D2 (i.e., the up and down viewing angle).

[0043] Figure 6B This is a schematic diagram showing the light output brightness of the switching panel 400 in sharing mode according to at least one embodiment of the present invention. Please refer to... Figure 6B When the driving circuit of the switching panel 400 causes the voltage difference between the first electrode 408 and the second electrodes 410, 410A to be non-zero, the light beam passes sequentially through the light control diaphragm 300 and the switching panel 400, and the output brightness at each viewing angle is as follows: Figure 6B As shown in M2, the emitted light intensity is uniformly distributed in the center, top and bottom, and left and right sides.

[0044] Therefore, even if the venetian blind diaphragm 200 located between the backlight module 100 and the switching panel 400 absorbs light from the left and right sides of the backlight module 100, the switching panel 400 can still evenly disperse the light, thus achieving a mode in which the left and right viewing angles and the up and down viewing angles are shared simultaneously.

[0045] In detail, with Figure 1A and Figure 5AFor example, the light beam from the backlight module 100 is absorbed on the left and right sides after passing through the venetian blind diaphragm 200. The light beams from the top and bottom sides of the venetian blind diaphragm 200, when passing through the light control diaphragm 300 with its light absorption axis A1 parallel to the first direction D1, will have linearly polarized beams in the second direction D2 (where azimuth angles are 90 degrees and 270 degrees) absorbed at increasingly larger angles. This results in only the beam in the positive viewing angle direction and the linearly polarized beam in the third direction D3. After passing through the enabled switching panels 400 and 400A (i.e., the voltage difference between the first electrode 408 and the second electrodes 410 and 410A is not zero), the third... The polarization state of the linearly polarized beam on D3 is changed to have a linearly polarized state on the second direction D2, and the remaining beams can be dispersed into beams with a wide viewing angle by the liquid crystal molecules near the first electrode 408 and the second electrodes 410, 410A in the enabled switching panel 400. The beams with a linear polarization state on the second direction D2 and the beams with a wide viewing angle from the enabled switching panel 400, 400A and the first polarizer 500 with the light absorption axis A2 parallel to the third direction D3 can pass through the first polarizer 500 in the same or similar proportions at all azimuth angles. Therefore, the effect can be shared simultaneously on the third direction D3 (i.e., the left and right viewing angle) and the second direction D2 (i.e., the up and down viewing angle).

[0046] In summary, the switchable privacy display device and its control method according to at least one embodiment of the present invention, by using a switching panel with the second alignment direction of the second alignment layer substantially the same as the light absorption axis of the second polarizer and perpendicular to the stacking direction, can enable the switchable privacy display device to achieve a mode of simultaneous privacy protection or simultaneous sharing of the left and right viewing angles and the top and bottom viewing angles.

[0047] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Those skilled in the art to which this invention pertains may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A switchable privacy display device, comprising: One backlight module; A switching panel is disposed on the backlight module along a stacking direction, and includes: First substrate; A second substrate; A liquid crystal layer is disposed between the first substrate and the second substrate; A first electrode is disposed between the first substrate and the liquid crystal layer; A second electrode is disposed between the first substrate and the liquid crystal layer, and is electrically insulated from the first electrode; A first alignment layer is disposed between the first electrode and the liquid crystal layer, and has a first alignment direction; and A second alignment layer is disposed between the liquid crystal layer and the second substrate, and has a second alignment direction; A 100-blind diaphragm, comprising a plurality of light-blocking portions extending in an extension direction perpendicular to the stacking direction; A light control film, wherein, in the stacking direction, the venetian blind film and the light control film are disposed between the backlight module and the switching panel, and the light absorption axis of the light control film is parallel to the stacking direction; First polarizer; A display panel; and A second polarizer, wherein the first substrate, the second substrate, the first polarizer, the display panel and the second polarizer are stacked sequentially along the stacking direction, and the second alignment direction is the same as the light absorption axis of the second polarizer and perpendicular to the stacking direction.

2. The switchable privacy display device as claimed in claim 1, wherein the first alignment direction is the same as the second alignment direction.

3. The switchable privacy display device as claimed in claim 1, wherein the first alignment direction is parallel to the stacking direction.

4. The switchable privacy display device as claimed in claim 1, wherein the light absorption axis of the first polarizer is perpendicular to the stacking direction and the light absorption axis of the second polarizer.

5. The switchable privacy display device as claimed in claim 4, wherein the venetian blind film further includes a plurality of light-transmitting portions extending along the extending direction, wherein the plurality of light-transmitting portions and the plurality of light-blocking portions are arranged alternately along an arrangement direction, and the arrangement direction is parallel to the light absorption axis of the first polarizer.

6. The switchable privacy display device as claimed in claim 1, wherein the switching panel further comprises: An insulating layer is disposed on the first substrate and located between the first electrode and the second electrode.

7. The switchable privacy display device as claimed in claim 1, wherein the first electrode comprises a plurality of first sub-electrodes arranged at intervals.

8. The switchable privacy display device as claimed in claim 7, wherein the second electrode includes a plurality of second sub-electrodes arranged at intervals, and the plurality of second sub-electrodes are arranged alternately with the plurality of first sub-electrodes.

9. The switchable privacy display device as claimed in claim 1, wherein the liquid crystal layer comprises positive liquid crystal.

10. A control method for switching a switchable privacy display device between a privacy mode and a sharing mode: Provide a switchable privacy display device as described in claim 1; To switch the switchable privacy display device to the privacy mode by making the voltage difference between the first electrode and the second electrode zero; and The voltage difference between the first electrode and the second electrode is not zero, so that the switchable privacy display device is switched to the sharing mode.

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