Privacy module and display device

Abstract

This invention provides a light source module and a display device. [Solution] The privacy filter module and display device include a first electrically controlled viewing angle switcher and a first polarizing sheet. The first electrically controlled viewing angle switcher includes a first alignment layer, a second alignment layer, a first liquid crystal layer, and a plurality of first spacers. The angle between the first alignment direction of the first alignment layer and the second alignment direction of the second alignment layer is in the range of 165 to 195 degrees. The first spacers have a first refractive index that is greater than the first ordinary refractive index of the first liquid crystal layer and smaller than the first non-ordinary refractive index of the first liquid crystal layer. When the absolute value of the difference between the first refractive index and the first non-ordinary refractive index is less than 0.05, the first absorption axis of the first polarizing sheet is perpendicular to the first alignment direction. When the absolute value of the difference between the first refractive index and the first ordinary refractive index is less than 0.05, the first absorption axis is parallel to the first alignment direction.

Description

TECHNICAL FIELD

[0001] The present invention relates to a display device provided with an optical module, and particularly to a display device provided with a peep prevention module.

BACKGROUND ART

[0002] In order to impart a peep prevention function to a display device, a technical solution has been proposed in which an electrically controllable viewing angle (view angle) control element is disposed above a display panel. Generally speaking, such a viewing angle control element is, for example, a liquid crystal device capable of electrically controlling and changing the phase retardation amount. In the manufacturing process of liquid crystal devices, a liquid crystal layer for light modulation may be formed by injecting a liquid crystal material into the cavity between two light-transmissive substrates. In order to control the film thickness of the liquid crystal layer and its uniformity, it is necessary to control and maintain the height of the cavity by disposing a plurality of spacers inside the cavity.

[0003] However, as the pixel size of the display device decreases (the pixel resolution increases), the influence of these spacers in the viewing angle control element on display quality becomes more serious. For example, when the display pixel size of the display panel is reduced to approach the size of the spacers of the viewing angle control element, when part of light passes through the interface between the spacer and the liquid crystal layer, due to the optical path deflection (shift) occurring at the interface, the user may observe bright spots at the distribution positions of the spacers, or observe a sparkle phenomenon when changing the viewing angle, which may affect the visual effect.

[0004] Note that this "Background Art" section is only intended to assist in understanding the content of the present invention, so the content disclosed in this "Background Art" section may include techniques not known to those skilled in the art. Therefore, the content disclosed in this "Background Art" section does not mean that the content or the problem to be solved by one or more embodiments of the present invention was already well known to those skilled in the art before the filing of the present application.

SUMMARY OF THE INVENTION

[0005] The object of the present invention is to provide a privacy protection module and display device with better display quality.

[0006] Other objectives and advantages of the present invention can be further understood from the technical features disclosed herein. [Means for solving the problem]

[0007] To achieve one, some, or all of the above-mentioned objectives or other objectives, an embodiment of the present invention provides a privacy module. The privacy module includes a first electrically controlled viewing angle switch, a first polarizing sheet, and a second polarizing sheet. The first electrically controlled viewing angle switch includes a first substrate, a second substrate, a first alignment layer, a second alignment layer, a first liquid crystal layer, and a plurality of first spacers. The first and second substrates are stacked on top of each other. The first alignment layer is installed on the first substrate and has a first alignment direction. The second alignment layer is installed on the second substrate and has a second alignment direction. The angle between the first and second alignment directions is in the range of 165 to 195 degrees. The first liquid crystal layer is installed between the first and second alignment layers and has a plurality of first liquid crystal molecules. Each of these first liquid crystal molecules has a first optical axis, a first extraordinary ray refractive index, and a first ordinary ray refractive index. The first non-ordinary refractive index is greater than the first ordinary refractive index. Multiple first spacers are placed between the first substrate and the second substrate, and each has a first refractive index. The first refractive index is greater than the first ordinary refractive index and less than the first non-ordinary refractive index. The first polarizing sheet is placed on the side of the first liquid crystal layer on which the first alignment layer is provided, and has a first absorption axis. The axial direction of the first absorption axis is parallel or perpendicular to the first alignment direction. The second polarizing sheet is placed on the side of the first liquid crystal layer on which the second alignment layer is provided, and has a second absorption axis. The axial direction of the second absorption axis is parallel or perpendicular to the second alignment direction. When the absolute value of the difference between the first refractive index and the first non-ordinary refractive index is less than 0.05, the axial direction of the first absorption axis is perpendicular to the first alignment direction. When the absolute value of the difference between the first refractive index and the first ordinary refractive index is less than 0.05, the axial direction of the first absorption axis is parallel to the first alignment direction.

[0008] To achieve one, some, or all of the above-mentioned objectives or other objectives, a display device is provided according to one embodiment of the present invention. The display device includes a self-illuminating display panel and a privacy module. The privacy module is installed on the display surface side of the self-illuminating display panel and includes a first electrically controlled viewing angle switcher, a first polarizing sheet, and a second polarizing sheet. The first electrically controlled viewing angle switcher includes a first substrate, a second substrate, a first alignment layer, a second alignment layer, a first liquid crystal layer, and a plurality of first spacers. The first and second substrates are installed stacked on top of each other. The first alignment layer is installed on the first substrate and has a first alignment direction. The second alignment layer is installed on the second substrate and has a second alignment direction. The angle between the first and second alignment directions is in the range of 165 to 195 degrees. The first liquid crystal layer is installed between the first and second alignment layers and has a plurality of first liquid crystal molecules. Each of these first liquid crystal molecules has a first optical axis, a first non-ordinary refractive index, and a first ordinary refractive index. The first non-ordinary refractive index is greater than the first ordinary refractive index. Multiple first spacers are placed between the first substrate and the second substrate, and each has a first refractive index. The first refractive index is greater than the first ordinary refractive index and less than the first non-ordinary refractive index. The first polarizing sheet is placed on the side of the first liquid crystal layer on which the first alignment layer is provided, and has a first absorption axis. The axial direction of the first absorption axis is parallel or perpendicular to the first alignment direction. The second polarizing sheet is placed on the side of the first liquid crystal layer on which the second alignment layer is provided, and has a second absorption axis. The axial direction of the second absorption axis is parallel or perpendicular to the second alignment direction. When the absolute value of the difference between the first refractive index and the first non-ordinary refractive index is less than 0.05, the axial direction of the first absorption axis is perpendicular to the first alignment direction. When the absolute value of the difference between the first refractive index and the first ordinary refractive index is less than 0.05, the axial direction of the first absorption axis is parallel to the first alignment direction. [Effects of the Invention]

[0009] As described above, in the privacy filter module and display device according to one embodiment of the present invention, a plurality of first spacers define a accommodating space for filling the first liquid crystal layer between the first substrate and the second substrate of the first electrically controlled viewing angle switcher. The first refractive index of the first spacer is within the range between the first ordinary refractive index and the first non-ordinary refractive index of the first liquid crystal layer. Since the arrangement relationship between the first absorption axis of the first polarizing sheet and the first orientation direction of its adjacent first orientation layer depends on the difference between the first refractive index of the first spacer and the first ordinary refractive index or the first non-ordinary refractive index, the optical path deflection angle when light passes through the interface between the first spacer and the first liquid crystal layer can be effectively reduced. This makes it possible to avoid the phenomenon of screen flickering when the user views the display device, thereby improving the visual effect of the display screen.

[0010] Although the present invention has been disclosed above through the examples, these are not intended to limit the invention, and those skilled in the art can make some changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims. [Brief explanation of the drawing]

[0011] [Figure 1] This is a cross-sectional view of a display device according to the first embodiment of the present invention. [Figure 2A] This figure shows the arrangement relationship between the orientation direction of the orientation layer, the axial direction of the absorption axis of the polarizing sheet, and the axial direction of the anti-peeping axis on both sides. [Figure 2B] This is a modified version of Figure 2A. [Figure 3] This is a cross-sectional view of a display device according to a second embodiment of the present invention. [Figure 4A] This is a diagram (part 1) showing the arrangement relationship between the orientation direction of the orientation layer, the axial direction of the absorption axis of the polarizing sheet, and the axial direction of the anti-peeping devices on both sides in Figure 3. [Figure 4B] This is a diagram (part 2) showing the arrangement relationship between the orientation direction of the orientation layer, the axial direction of the absorption axis of the polarizing sheet, and the axial direction of the anti-peeping devices on both sides in Figure 3. [Figure 4C]This is a modified version of Figure 4B. [Modes for carrying out the invention]

[0012] The above-mentioned and other technical details, features, functions, and effects of the present invention will be clarified by the following detailed description of preferred embodiments based on the attached drawings. Note that the directional terms used in the following embodiments, such as up, down, left, right, front, and back, are merely directions as shown in the attached drawings. Therefore, the directional terms used are solely for illustrative purposes and not intended to limit the present invention.

[0013] Figure 1 is a cross-sectional view of a display device according to the first embodiment of the present invention. Figure 2A is a diagram showing the arrangement relationship in the orientation direction of the orientation layer, the axial direction of the absorption axis of the polarizing sheet, and the axial direction of the anti-peeping devices on both sides in Figure 1. Figure 2B is a modified example of Figure 2A. Note that the angular arrangement relationship shown in Figures 2A and 2B is, for example, the angular arrangement relationship in the top view direction (for example, direction Z) of the display device 10.

[0014] As shown in Figure 1, the display device 10 includes a self-illuminating display panel 100 and a privacy module 200. The privacy module 200 is installed on the display surface 100ds of the self-illuminating display panel 100 (for example, the surface from which the display light leaves the self-illuminating display panel 100) and includes a first electrically controlled viewing angle switch 210, a second electrically controlled viewing angle switch 220, a first polarizing sheet POL1, a second polarizing sheet POL2, and a third polarizing sheet POL3. The first electrically controlled viewing angle switch 210 is installed between the second electrically controlled viewing angle switch 220 and the self-illuminating display panel 100. The first polarizing sheet POL1 is installed between the first electrically controlled viewing angle switch 210 and the self-illuminating display panel 100. The second polarizing sheet POL2 is installed between the first electrically controlled viewing angle switch 210 and the second electrically controlled viewing angle switch 220. The third polarizing sheet POL3 is installed on the opposite side of the second electrically controlled viewing angle switch 220 from the first electrically controlled viewing angle switch 210 (i.e., the second electrically controlled viewing angle switch 220 is installed between the third polarizing sheet POL3 and the first electrically controlled viewing angle switch 210). The self-illuminating display panel 100 and the first polarizing sheet POL1 are bonded, for example, by a non-full lamination method, such as air bonding, while the other optical elements are bonded, for example, by a full lamination method.

[0015] More specifically, the first polarizing sheet POL1, the first electrically controlled viewing angle switch 210, the second polarizing sheet POL2, the second electrically controlled viewing angle switch 220, and the third polarizing sheet POL3 are sequentially stacked on the display surface 100ds of the self-illuminating display panel 100 along direction Z. Direction Z is, for example, perpendicular to the display surface 100ds.

[0016] The self-illuminating display panel 100 is, for example, an organic light-emitting diode (OLED) display panel, a micro light-emitting diode (micro-LED) display panel, or a mini light-emitting diode (mini-LED) display panel, but is not limited to these.

[0017] The first electrically controlled viewing angle switcher 210 includes a first substrate SUB1, a second substrate SUB2, a first liquid crystal layer LCL1, a first alignment layer AL1, and a second alignment layer AL2. The first alignment layer AL1 is installed on the first substrate SUB1 and is located between the first liquid crystal layer LCL1 and the first polarizing sheet POL1 (or between the first liquid crystal layer LCL1 and the first substrate SUB1). The second alignment layer AL2 is installed on the second substrate SUB2 and is located between the first liquid crystal layer LCL1 and the second polarizing sheet POL2 (or between the first liquid crystal layer LCL1 and the second substrate SUB2). The first liquid crystal layer LCL1 is installed between the first alignment layer AL1 and the second alignment layer AL2.

[0018] The second electrically controlled viewing angle switcher 220 includes a third substrate SUB3, a fourth substrate SUB4, a second liquid crystal layer LCL2, a third alignment layer AL3, and a fourth alignment layer AL4. The third alignment layer AL3 is installed on the third substrate SUB3 and is located between the second liquid crystal layer LCL2 and the second polarizing sheet POL2 (or between the second liquid crystal layer LCL2 and the third substrate SUB3). The fourth alignment layer AL4 is installed on the fourth substrate SUB4 and is located between the second liquid crystal layer LCL2 and the third polarizing sheet POL3 (or between the second liquid crystal layer LCL2 and the fourth substrate SUB4). The second liquid crystal layer LCL2 is installed between the third alignment layer AL3 and the fourth alignment layer AL4.

[0019] The substrate material of the electrically controlled viewing angle switch may include glass, triacetate fiber (TAC), cyclo-olefin polymer (COP), polycarbonate (PC), polymethyl methacrylate (PMMA), polyimide (PI), other suitable polymers, or a sheet (plate material) having a phase retardation amount (e.g., a stretch-type compensation film).

[0020] It should be noted that the two alignment layers of each electrically controlled viewing angle switch are configured to be used to determine the alignment state of the liquid crystal layer in its natural state (e.g., a state not subjected to the action of an electric field). To drive the liquid crystal layer, each electrically controlled viewing angle switch may further include two electrode layers respectively disposed on two opposite sides of the liquid crystal layer. When the two electrode layers are enabled to have a potential difference, the plurality of liquid crystal molecules in the liquid crystal layer can be deflected under the action of the electric field formed between the two electrode layers. The electrode layer is, for example, a light-transmissive electrode, and the material of the light-transmissive electrode may include a metal oxide, such as indium tin oxide, indium zinc oxide, indium tin oxide, aluminum tin oxide, or other suitable oxides, or at least two stacked layers of the above, but is not limited thereto.

[0021] For example, in this embodiment, the first electrically controlled viewing angle switch 210 further includes a first electrode layer EL1 and a second electrode layer EL2, which are respectively disposed on the first substrate SUB1 and the second substrate SUB2, and are used to drive the plurality of first liquid crystal molecules LC1 in the first liquid crystal layer LCL1 to rotate (roll). Similarly, the second electrically controlled viewing angle switch 220 further includes a third electrode layer EL3 and a fourth electrode layer EL4, which are respectively disposed on the third substrate SUB3 and the fourth substrate SUB4, and are used to drive the plurality of second liquid crystal molecules LC2 in the second liquid crystal layer LCL2 to rotate.

[0022] By adjusting the applied voltage between the first electrode layer EL1 and the second electrode layer EL2 of the first electrically controlled viewing angle switch 210 and the applied voltage between the third electrode layer EL3 and the fourth electrode layer EL4 of the second electrically controlled viewing angle switch 220, the display device 10 can be caused to operate by switching between a share mode and a peeping prevention mode. For example, when a first voltage is applied between the first electrode layer EL1 and the second electrode layer EL2, and / or a third voltage is applied between the third electrode layer EL3 and the fourth electrode layer EL4, the display device 10 operates in the peeping prevention mode. When a second voltage is applied between the first electrode layer EL1 and the second electrode layer EL2, and a fourth voltage is applied between the third electrode layer EL3 and the fourth electrode layer EL4, the display device 10 operates in the share mode.

[0023] In the present invention, the liquid crystal layer of the electrically controlled viewing angle switch can be driven in a TN (twisted-nematic) mode or an ECB (electrically controlled birefringence) mode. For example, in the present embodiment, both the first electrically controlled viewing angle switch 210 and the second electrically controlled viewing angle switch 220 are driven in the ECB mode, and the first liquid crystal layer LCL1 and the second liquid crystal layer LCL2 are, for example, all positive type liquid crystals.

[0024] Referring to FIG. 1 and FIG. 2A at the same time, in the present embodiment, both the first electrically controlled viewing angle switch 210 and the second electrically controlled viewing angle switch 220 have the same two-side peeping prevention axis direction DPAX that is perpendicular to the direction Z. In other words, both of these two electrically controlled viewing angle switches can enable the display device 10 to have a peeping prevention effect within the two-side viewing angle range along the two-side peeping prevention axis direction DPAX. Specifically, the two-side peeping prevention axis direction DPAX includes a 90-degree direction and a -90-degree direction that are opposite to each other in the same dimension (for example, the horizontal dimension in FIG. 2A, whose viewing angle ranges from 90 degrees to -90 degrees, wherein the 0-degree viewing angle is the front viewing angle direction (for example, direction Z)). Among them, the 90-degree direction is, for example, the direction toward the right side of FIG. 2A, and the -90-degree direction is, for example, the direction toward the left side of FIG. 2A.

[0025] In this embodiment, the angle α1 between the first orientation direction AD1 of the first orientation layer AL1 and the -90-degree direction of the double-sided anti-peeping axial direction DPAX may be 90 degrees. The angle α2 between the second orientation direction AD2 of the second orientation layer AL2 and the -90-degree direction of the double-sided anti-peeping axial direction DPAX may be 95 degrees. That is, the angle γ1 between the first orientation direction AD1 and the second orientation direction AD2 is 175 degrees, but is not limited to this. In other embodiments, the angle between the first orientation direction AD1 and the second orientation direction AD2 may be in the range of 165 degrees to 195 degrees.

[0026] Similarly, the angle α3 between the third orientation direction AD3 of the third orientation layer AL3 and the -90-degree direction of the double-sided anti-peeping axis DPAX may be 95 degrees. The angle α4 between the fourth orientation direction AD4 of the fourth orientation layer AL4 and the -90-degree direction of the double-sided anti-peeping axis DPAX may be 90 degrees. That is, the angle γ2 between the third orientation direction AD3 and the fourth orientation direction AD4 is 175 degrees, but is not limited to this. In other embodiments, the angle between the third orientation direction AD3 and the fourth orientation direction AD4 may be in the range of 165 degrees to 195 degrees.

[0027] More specifically, in this embodiment, the first orientation direction AD1 and the fourth orientation direction AD4 are parallel to each other and perpendicular to the double-sided privacy screen axis DPAX, and the second orientation direction AD2 is parallel to the third orientation direction AD3.

[0028] In this embodiment, the axial direction of the first absorption axis AX1 of the first polarizing sheet POL1 may be perpendicular to the first orientation direction AD1, and the axial direction of the third absorption axis AX3 of the third polarizing sheet POL3 may be perpendicular to the fourth orientation direction AD4. That is, the axial directions of the first absorption axis AX1 and the third absorption axis AX3 are parallel to each other. The angle β2 between the -90 degree direction of the double-sided privacy axial direction DPAX and the second absorption axis AX2 of the second polarizing sheet POL2 is, for example, 5 degrees, but is not limited to this.

[0029] Furthermore, each of the multiple first liquid crystal molecules LC1 in the first liquid crystal layer LCL1 has a first optical axis OA1, a first non-ordinary refractive index in a direction parallel to the first optical axis OA1, and a first ordinary refractive index in a direction perpendicular to the first optical axis OA1. Each of the multiple second liquid crystal molecules LC2 in the second liquid crystal layer LCL2 has a second optical axis OA2, a second non-ordinary refractive index in a direction parallel to the second optical axis OA2, and a second ordinary refractive index in a direction perpendicular to the second optical axis OA2.

[0030] In Figure 2A, the first optical axis OA1 is the first optical axis OA1 of the first liquid crystal molecule LC1 that is close to the first orientation layer AL1 (or first polarizing sheet POL1) in the first liquid crystal layer LCL1 (for example, the molecular long axis of the first liquid crystal molecule LC1). In Figure 2A, the second optical axis OA2 is the second optical axis OA2 of the second liquid crystal molecule LC2 that is close to the third orientation layer AL3 (or second polarizing sheet POL2) in the second liquid crystal layer LCL2.

[0031] To control the film thickness and uniformity of the first liquid crystal layer LCL1 and the second liquid crystal layer LCL2, the first electrically controlled viewing angle switch 210 is further provided with a plurality of first spacers SP1 between the first substrate SUB1 and the second substrate SUB2, and the second electrically controlled viewing angle switch 220 is further provided with a plurality of second spacers SP2 between the third substrate SUB3 and the fourth substrate SUB4. The first spacers SP1 and the second spacers SP2 each have a first refractive index and a second refractive index, respectively, of which the first refractive index is greater than the first ordinary refractive index and less than the first non-ordinary refractive index, and the second refractive index is greater than the second ordinary refractive index and less than the second non-ordinary refractive index. Preferably, the width of the first spacers SP1 and the second spacers SP2 along any direction perpendicular to direction Z may be less than 15 μm.

[0032] For example, in this embodiment, the absolute value of the difference between the first refractive index and the first non-ordinary refractive index is less than 0.05, and the absolute value of the difference between the second refractive index and the second non-ordinary refractive index is less than 0.05. Therefore, by positioning the first absorption axis AX1 of the first polarizing sheet POL1 so that its axial direction is perpendicular to the first orientation direction AD1, the difference (absolute value) in refractive index between the first spacer SP1 and the first liquid crystal layer LCL1 in the polarization direction of light (not shown) passing through the first polarizing sheet POL1 can be made less than 0.05. Thus, when light passes through the interface between the first spacer SP1 and the first liquid crystal layer LCL1, no significant optical path deflection occurs. Similarly, by positioning the second absorption axis AX2 of the second polarizing sheet POL2 perpendicular to the third orientation direction AD3, the difference (absolute value) in refractive index between the second spacer SP2 and the second liquid crystal layer LCL2 in the polarization direction of light (not shown) passing through the second polarizing sheet POL2 can be made smaller than 0.05. This prevents obvious optical path deflection from occurring when light passes through the interface between the second spacer SP2 and the second liquid crystal layer LCL2. As a result, when a user views the display device 10, they will not notice bright spots due to optical path deflection of light at the interface between the spacer and the liquid crystal layer, nor will they observe a glittering phenomenon when changing the viewing angle, thus improving the visual effect of the display screen.

[0033] However, the present invention is not limited thereto. In other modifications, the absolute value of the difference between the first refractive index and the first ordinary refractive index of the first spacer SP1 may be less than 0.05, and the absolute value of the difference between the second refractive index and the second ordinary refractive index of the second spacer SP2 may be less than 0.05. Therefore, in order to avoid the problem of users detecting bright spots when viewing the displayed image, the axial directions of the first absorption axis AX1 of the first polarizing sheet POL1 and the third absorption axis AX3 of the third polarizing sheet POL3 may be set parallel to the first orientation direction AD1, and the second absorption axis AX2 of the second polarizing sheet POL2 may be set parallel to the third orientation direction AD3 (as shown in Figure 2B).

[0034] In the modified example described above, the first electrode layer EL1 and the second electrode layer EL2 of the first electrically controlled viewing angle switcher 210 may have a second voltage applied in share mode that is higher than the first voltage applied in privacy mode, and the third electrode layer EL3 and the fourth electrode layer EL4 of the second electrically controlled viewing angle switcher 220 may have a fourth voltage applied in share mode that is higher than the third voltage applied in privacy mode. The first liquid crystal layer LCL1 and the second liquid crystal layer LCL2 are, for example, all positive liquid crystals. When the display device 10 operates in share mode, the axial directions of the molecular long axes of the first liquid crystal molecules LC1 and the second liquid crystal molecules LC2 tend to be aligned along direction Z, for example. Therefore, the absolute value of the difference in refractive index between the spacer and the liquid crystal layer does not differ significantly in each direction perpendicular to direction Z, thus further improving the bright spots caused by optical path deflection of light at the interface between the spacer and the liquid crystal layer.

[0035] Furthermore, in order to further improve the aforementioned problem of bright spots caused by the spacer, preferably, the absolute value of the difference between the ordinary ray refractive index and the extraordinary ray refractive index of the first liquid crystal layer LCL1 and the second liquid crystal layer LCL2 may be less than 0.12, and the height of the spacer along the stacking direction (e.g., direction Z) of the two adjacent substrates (e.g., heights H1 and H2 in Figure 1) may be greater than 5 μm and less than 10 μm, but is not limited to this.

[0036] Furthermore, in this embodiment, the privacy module 200 may selectively include compensating films 251 and 252. Compensating film 251 is placed between the first polarizing sheet POL1 and the first liquid crystal layer LCL1, and compensating film 252 is placed between the third polarizing sheet POL3 and the second liquid crystal layer LCL2. The out-of-plane phase delay (Rth) of each of the compensating films 251 and 252 may be in the range of 100 nm to 500 nm. In this embodiment, the out-of-plane phase delay of each of the compensating films 251 and 252 is, for example, 280 nm. In addition, a quarter-wavelength sheet (waveplate) WP1 may be further placed between the first polarizing sheet POL1 of the privacy module 200 and the self-emissive display panel 100. The angle φ between the optical axis OX of the quarter-wavelength sheet WP1 and the first absorption axis AX1 of the first polarizing sheet POL1 is 45 degrees.

[0037] In this embodiment, a reflective polarizing layer (not shown) or a metal grid polarizing layer (not shown) may be further installed between the second polarizing sheet POL2 and the third substrate SUB3, but the embodiment is not limited to these. As a result, when the display device 10 operates in privacy mode, ambient light can be reflected by the reflective polarizing layer within the privacy viewing angle range, thereby reducing the display contrast within the privacy viewing angle range of the display screen, and further improving the privacy effect.

[0038] The present invention will be described in more detail below with reference to several other embodiments, in which the same components will be given the same reference numerals, and the same technical content will be omitted. Since the omitted parts can be found in the embodiments described above, a detailed explanation of those parts will be omitted below.

[0039] Figure 3 is a cross-sectional view of a display device according to a second embodiment of the present invention. Figures 4A and 4B show the arrangement relationships in Figure 3 in the orientation direction of the orientation layer, the axial direction of the absorption axis of the polarizing sheet, and the axial direction of the anti-peeping devices on both sides. Figure 4C is a modified example of Figure 4B. Note that the angular arrangement relationships shown in Figures 4A, 4B, and 4C are, for example, the angular arrangement relationships in the top view direction (for example, direction Z) of the display device 20.

[0040] As shown in Figures 3, 4A, and 4B, the main difference between the display device 20 in this embodiment and the display device 10 in Figure 1 is that the driving method of the second electrically controlled viewing angle switch is different for the two. In this embodiment, the second liquid crystal layer LCL2-A of the second electrically controlled viewing angle switch 220A of the privacy protection module 200A is driven in TN mode, for example. In other words, the third orientation direction AD3 of the third orientation layer AL3-A of the second electrically controlled viewing angle switch 220A is perpendicular to the fourth orientation direction AD4 of the fourth orientation layer AL4-A. That is, the angle γ2 between the third orientation direction AD3 and the fourth orientation direction AD4 is 90 degrees.

[0041] Furthermore, the second electrically controlled viewing angle switch 220A has a one-sided anti-peeping direction SPD perpendicular to direction Z, and the one-sided anti-peeping direction SPD is parallel to the -90-degree direction of the double-sided anti-peeping axis DPAX of the first electrically controlled viewing angle switch 210, but is not limited to this. More specifically, the first electrically controlled viewing angle switch 210 can be configured so that the display device 20 has an anti-peeping effect throughout the viewing angle range on both sides along the double-sided anti-peeping axis DPAX, while the second electrically controlled viewing angle switch 220A can be configured so that the display device 20 has an anti-peeping effect within the viewing angle range on one side along the one-sided anti-peeping direction SPD.

[0042] The angle between the third orientation direction AD3 of the third orientation layer AL3-A and the fourth orientation direction AD4 of the fourth orientation layer AL4-A, and the one-sided privacy protection direction SPD, is within the range of 40 to 50 degrees or 130 to 140 degrees. For example, in this embodiment, the angle α3 between the third orientation direction AD3 and the one-sided privacy protection direction SPD may be 45 degrees, and the angle α4 between the fourth orientation direction AD4 and the one-sided privacy protection direction SPD may be 135 degrees.

[0043] Furthermore, the axial direction of the second absorption axis AX2 of the second polarizing sheet POL2 may be parallel to the third orientation direction AD3 of the third orientation layer AL3-A, and the axial direction of the third absorption axis AX3 of the third polarizing sheet POL3 may be parallel to the fourth orientation direction AD4 of the fourth orientation layer AL4-A, but is not limited to this. In other embodiments, the axial direction of the second absorption axis AX2 may be perpendicular to the third orientation direction AD3, and the axial direction of the third absorption axis AX3 may be perpendicular to the fourth orientation direction AD4.

[0044] In this embodiment, the second absorption axis AX2 of the second polarizing sheet POL2 may be perpendicular to the third absorption axis AX3 of the third polarizing sheet POL3, and the angle between each of the second absorption axis AX2 and the third absorption axis AX3 and the one-sided anti-peeping direction SPD may be in the range of 40 to 50 degrees or 130 to 140 degrees. For example, in this embodiment, the angle β2 between the second absorption axis AX2 and the one-sided anti-peeping direction SPD may be 135 degrees, and the angle β3 between the third absorption axis AX3 and the one-sided anti-peeping direction SPD may be 45 degrees.

[0045] The arrangement of the first electrically controlled field of view switch 210 and the first polarizing sheet POL1 in this embodiment is similar to that of the first electrically controlled field of view switch 210 and the first polarizing sheet POL1 in Figure 1. Therefore, a detailed explanation can be found in the relevant paragraphs of the above-mentioned embodiment, and a detailed explanation is omitted here.

[0046] In this embodiment, the privacy module 200A may further selectively include a half-wavelength sheet WP2, which is installed between the first electrically controlled viewing angle switch 210 and the second electrically controlled viewing angle switch 220A, and the half-wavelength sheet WP2 has a slow axis (delay axis) SX. When the absolute value of the difference between the first refractive index of the first spacer SP1 and the first non-ordinary optical refractive index of the first liquid crystal molecule LC1 is less than 0.05, the angle θ between the delay axis SX of the half-wavelength sheet WP2 and the axial direction DPAX of the privacy filter on both sides is 110 degrees (as shown in Figure 4B). When the absolute value of the difference between the first refractive index of the first spacer SP1 and the first ordinary optical refractive index of the first liquid crystal molecule LC1 is less than 0.05, the angle θ between the delay axis SX of the half-wavelength sheet WP2 and the axial direction DPAX of the privacy filter on both sides is 65 degrees (as shown in Figure 4C).

[0047] In addition to positioning the first absorption axis AX1 of the first polarizing sheet POL1 so that its axial direction is perpendicular to the first orientation direction AD1, arranging the slow axis SX of the half-wavelength sheet WP2 in the manner described above further prevents users from detecting bright spots caused by optical path deflection at the interface between the first spacer SP1 and the first liquid crystal layer LCL1 when viewing the display device 20, thereby further improving the visual effect of the display screen.

[0048] In this embodiment, in order to further improve the aforementioned problem of bright spots caused by the spacer, preferably, the absolute value of the difference between the ordinary ray refractive index and the extraordinary ray refractive index of the second liquid crystal layer LCL2-A may be less than 0.12 (in this embodiment, the absolute value of the difference between the ordinary ray refractive index and the extraordinary ray refractive index of the first liquid crystal layer LCL1 is not limited and may be, for example, greater than 0.12), and the height of the spacer along the stacking direction (for example, direction Z) of its two adjacent substrates (for example, height H2 in Figure 3) may be greater than 5 μm and less than 10 μm, but is not limited thereto.

[0049] In this embodiment, the privacy filter module 200A may further include a compensating film 253, which is installed between the second polarizing sheet POL2 and the second liquid crystal layer LCL2. In this embodiment, since the second liquid crystal layer LCL2-A of the second electrically controlled viewing angle switcher 220A is driven in TN mode, the out-of-plane phase delay amounts (Rth) of the compensating films 252 and 253 are in the range of -50nm to -300nm. In this embodiment, the sum of the out-of-plane phase delay amounts of the compensating films 252 and 253 is, for example, -200nm.

[0050] Based on the above, in the privacy protection module and display device according to one embodiment of the present invention, a plurality of first spacers define a accommodating space for filling the first liquid crystal layer between the first substrate and the second substrate of the first electrically controlled viewing angle switcher. The first refractive index of the first spacer is within the range between the first ordinary optical refractive index and the first non-ordinary optical refractive index of the first liquid crystal layer. Since the arrangement relationship between the first absorption axis of the first polarizing sheet and the first orientation direction of its adjacent first orientation layer depends on the difference between the first refractive index of the first spacer and the first ordinary optical refractive index or the first non-ordinary optical refractive index, the optical path deflection angle when light passes through the interface between the first spacer and the first liquid crystal layer can be effectively reduced. As a result, the privacy protection module and display device according to one embodiment of the present invention have the advantage of improving the visual effect of the display screen, as they can at least prevent users from noticing the flickering phenomenon when observing the display device.

[0051] The present invention has been disclosed above based on the aforementioned preferred embodiments, but the aforementioned preferred embodiments are not intended to limit the invention, and those skilled in the art can make minor modifications and embellishments to the invention as long as they do not deviate from the spirit and scope of the invention; therefore, the scope of protection of the present invention shall be as defined in the attached claims. Furthermore, no embodiment or claim of the present invention is required to achieve all the purposes, advantages, or features disclosed herein. Also, parts of the abstract and the title of the invention are for the sole purpose of assisting in the search of literature and do not limit the scope of rights of the present invention. Furthermore, terms such as “first,” “second,” etc., used herein or in the claims, are for the sole purpose of naming components or distinguishing different embodiments or scopes, and do not limit the quantitative upper or lower limits of components. [Explanation of Symbols]

[0052] 10, 20: Display device 100: Self-illuminating display panel 100ds:Display surface 200, 200A: Privacy module 210: First Electric Controlled Field of View Switcher 220, 220A: Second Electrically Controlled Field of View Switcher 251, 252, 253: Compensation film DPAX: Dual-sided privacy screen (axial) AD1~AD4: First orientation direction~Fourth orientation direction AL1: First alignment layer AL2: Second alignment layer AL3, AL3-A: Third alignment layer AL4, AL4-A: Fourth alignment layer AX1~AX3: First absorption axis~Third absorption axis EL1~EL4: 1st electrode layer ~ 4th electrode layer H1, H2: Height LC1: First liquid crystal molecule LC2: Second liquid crystal molecule LCL1: First liquid crystal layer LCL2, LCL2-A: Second liquid crystal layer OA1: First optical axis OA2: Second optical axis OX: Optical axis POL1: First Polarizing Sheet POL2: Second polarizing sheet POL3: Third Polarizing Sheet SP1: First Spacer SP2: Second Spacer SPD: One-sided privacy protection SUB1~SUB4: 1st board ~ 4th board SX: slow axis WP1: 1 / 4 wavelength sheet WP2: 1 / 2 wavelength sheet Z: Direction α1, α2, α3, α4, γ1, γ2, β2, β3, φ, θ: Included angle

Claims

1. It is a privacy filter module, Includes a first electrically controlled field of view switch, a first polarizing sheet, and a second polarizing sheet. The first electrically controlled field of view switcher is, A first substrate and a second substrate are installed stacked on top of each other; A first orientation layer installed on the first substrate and having a first orientation direction; A second orientation layer, which is installed on the second substrate and has a second orientation direction, wherein the angle between the first orientation direction and the second orientation direction is in the range of 165 degrees to 195 degrees; A first liquid crystal layer disposed between the first orientation layer and the second orientation layer, and having a plurality of first liquid crystal molecules, wherein each of the plurality of first liquid crystal molecules has a first optical axis, a first non-ordinary refractive index and a first ordinary refractive index, and the first non-ordinary refractive index is greater than the first ordinary refractive index; and A plurality of first spacers, each having a first refractive index, are installed between the first substrate and the second substrate, and each of these first spacers has a first refractive index greater than the first ordinary refractive index and less than the first non-ordinary refractive index. The first polarizing sheet is installed on the side of the first liquid crystal layer on which the first orientation layer is provided, and has a first absorption axis, the axial direction of the first absorption axis is parallel or perpendicular to the first orientation direction, The second polarizing sheet is installed on the side of the first liquid crystal layer on which the second orientation layer is provided, and has a second absorption axis, the axial direction of the second absorption axis is parallel or perpendicular to the second orientation direction. A privacy module in which, when the absolute value of the difference between the first refractive index and the first non-ordinary refractive index is less than 0.05, the axial direction of the first absorption axis is perpendicular to the first orientation direction, and when the absolute value of the difference between the first refractive index and the first ordinary refractive index is less than 0.05, the axial direction of the first absorption axis is parallel to the first orientation direction.

2. The privacy protection module according to claim 1, Further comprising a second electrically controlled viewing angle switch and a third polarizing sheet, The second polarizing sheet is located between the first electrically controlled field of view switch and the second electrically controlled field of view switch. The second electrically controlled field of view switcher is, Third and fourth boards are installed stacked on top of each other; A third orientation layer, which is installed on the third substrate and has a third orientation direction; A fourth orientation layer, which is installed on the fourth substrate and has a fourth orientation direction, wherein the angle between the third orientation direction and the fourth orientation direction is in the range of 165 degrees to 195 degrees; A second liquid crystal layer disposed between the third orientation layer and the fourth orientation layer, and having a plurality of second liquid crystal molecules, wherein each of the plurality of second liquid crystal molecules has a second optical axis, a second non-ordinary refractive index and a second ordinary refractive index, and the second non-ordinary refractive index is greater than the second ordinary refractive index; and A plurality of second spacers are installed between the third substrate and the fourth substrate, each having a second refractive index, wherein the second refractive index is greater than the second ordinary refractive index and less than the second non-ordinary refractive index, and the plurality of second spacers include this plurality of second spacers. The second electrically controlled field of view switch is located between the first electrically controlled field of view switch and the third polarizing sheet. The third polarizing sheet has a third absorption axis, and the third absorption axis is parallel or perpendicular to the fourth orientation direction. A privacy module in which, when the absolute value of the difference between the second refractive index and the second non-ordinary refractive index is less than 0.05, the axial direction of the second absorption axis is perpendicular to the third orientation direction, and when the absolute value of the difference between the second refractive index and the second ordinary refractive index is less than 0.05, the axial direction of the second absorption axis is parallel to the third orientation direction.

3. The privacy protection module according to claim 2, An anti-peeping module in which the first electrically controlled viewing angle switch and the second electrically controlled viewing angle switch each have anti-peeping axis directions on both sides, the first orientation direction and the fourth orientation direction are perpendicular to the anti-peeping axis directions on both sides, and the second orientation direction is parallel to the third orientation direction.

4. The privacy protection module according to claim 2, A first compensation film placed between the first polarizing sheet and the first liquid crystal layer; and The present invention further includes a second compensation film placed between the third polarizing sheet and the second liquid crystal layer, A privacy filter module in which the out-of-plane phase delay amounts of the first compensation film and the second compensation film are in the range of 100 nm to 500 nm.

5. The privacy protection module according to claim 1, Further comprising a second electrically controlled viewing angle switch and a third polarizing sheet, The second polarizing sheet is located between the first electrically controlled field of view switch and the second electrically controlled field of view switch. The second electrically controlled field of view switcher is, Third and fourth boards are installed stacked on top of each other; A third orientation layer, which is installed on the third substrate and has a third orientation direction; A fourth orientation layer installed on the fourth substrate and having a fourth orientation direction, wherein the third orientation direction is perpendicular to the fourth orientation direction; and It includes a second liquid crystal layer placed between the third alignment layer and the fourth alignment layer, The second electrically controlled field of view switch is located between the first electrically controlled field of view switch and the third polarizing sheet. A privacy module wherein the third polarizing sheet has a third absorption axis, and the third absorption axis is parallel or perpendicular to the fourth orientation direction.

6. The privacy protection module according to claim 5, An anti-peeping module wherein the first electrically controlled viewing angle switch has a double-sided anti-peeping axis direction, the second electrically controlled viewing angle switch has a single-sided anti-peeping direction, the single-sided anti-peeping direction is parallel to the double-sided anti-peeping axis direction, the first orientation direction is perpendicular to the double-sided anti-peeping axis direction, and the angle between each of the third and fourth orientation directions and the single-sided anti-peeping direction is in the range of 40 to 50 degrees or 130 to 140 degrees.

7. The privacy protection module according to claim 6, A privacy module in which the second absorption axis of the second polarizing sheet is perpendicular to the third absorption axis of the third polarizing sheet, and the angle between each of the second and third absorption axes and the one-sided privacy protection direction is in the range of 40 to 50 degrees or 130 to 140 degrees.

8. The privacy protection module according to claim 6, The present invention further includes a half-wavelength sheet installed between the first electrically controlled field of view switch and the second electrically controlled field of view switch, An anti-peeping module in which, when the absolute value of the difference between the first refractive index and the first non-ordinary refractive index is less than 0.05, the angle between the retard axis of the half-wavelength sheet and the axis of the anti-peeping on both sides is 110 degrees, and when the absolute value of the difference between the first refractive index and the first ordinary refractive index is less than 0.05, the angle between the retard axis of the half-wavelength sheet and the axis of the anti-peeping on both sides is 65 degrees.

9. The privacy protection module according to claim 5, A first compensation film placed between the second polarizing sheet and the second liquid crystal layer; and The present invention further includes a second compensation film placed between the third polarizing sheet and the second liquid crystal layer, A privacy module wherein the out-of-plane phase delay amounts of the first compensation film and the second compensation film are in the range of -50 nm to -300 nm.

10. The privacy protection module according to claim 1, A privacy module wherein the absolute value of the difference between the first non-ordinary refractive index and the first ordinary refractive index is less than 0.12, and the height of each of the plurality of first spacers along the stacking direction of the first substrate and the second substrate is greater than 5 μm and less than 10 μm.

11. A display device, Includes a self-illuminating display panel and a privacy filter module, The privacy protection module is installed on the display side of the self-illuminating display panel. The aforementioned privacy filter module includes a first electrically controlled viewing angle switch, a first polarizing sheet, and a second polarizing sheet. The first electrically controlled field of view switcher is, A first substrate and a second substrate are installed stacked on top of each other; A first orientation layer installed on the first substrate and having a first orientation direction; A second orientation layer, which is installed on the second substrate and has a second orientation direction, wherein the angle between the first orientation direction and the second orientation direction is in the range of 165 degrees to 195 degrees; A first liquid crystal layer disposed between the first orientation layer and the second orientation layer, and having a plurality of first liquid crystal molecules, wherein each of the plurality of first liquid crystal molecules has a first optical axis, a first non-ordinary refractive index and a first ordinary refractive index, and the first non-ordinary refractive index is greater than the first ordinary refractive index; and A plurality of first spacers, each having a first refractive index, are installed between the first substrate and the second substrate, and each of these first spacers has a first refractive index greater than the first ordinary refractive index and less than the first non-ordinary refractive index. The first polarizing sheet is installed on the side of the first liquid crystal layer on which the first orientation layer is provided, and has a first absorption axis, the axial direction of the first absorption axis is parallel or perpendicular to the first orientation direction, The second polarizing sheet is installed on the side of the first liquid crystal layer on which the second orientation layer is provided, and has a second absorption axis, the axial direction of the second absorption axis is parallel or perpendicular to the second orientation direction. A display device in which, when the absolute value of the difference between the first refractive index and the first non-ordinary refractive index is less than 0.05, the axial direction of the first absorption axis is perpendicular to the first orientation direction, and when the absolute value of the difference between the first refractive index and the first ordinary refractive index is less than 0.05, the axial direction of the first absorption axis is parallel to the first orientation direction.

12. A display device according to claim 11, The first electrically controlled field of view switcher further includes a first electrode layer and a second electrode layer, The first electrode layer and the second electrode layer are respectively installed on the first substrate and the second substrate, and are used to drive the plurality of first liquid crystal molecules in the first liquid crystal layer to rotate so that the display device can switch between share mode and privacy mode. A display device that operates in the privacy mode when there is a first voltage between the first electrode layer and the second electrode layer, and operates in the share mode when there is a second voltage between the first electrode layer and the second electrode layer, wherein the second voltage is higher than the first voltage.

13. A display device according to claim 11, The present invention further includes a quarter-wavelength sheet installed between the self-illuminating display panel and the first polarizing sheet, A display device in which the angle between the optical axis of the quarter-wavelength sheet and the first absorption axis of the first polarizing sheet is 45 degrees.

Images