Viewing Angle Conversion Display Device

Abstract

This improves the sense of alienation caused by the difference in field of view between the field of view control area and the shared area. [Solution] In one embodiment of the present disclosure, the display area includes a viewing angle switching display device, the display area of ​​which is configured to include a viewing angle control area on which the display device operates to switch between a viewing angle control mode and a shared mode, a shared area on which the display device operates in a shared mode, and a boundary area located between the viewing angle control area and the shared area on which the display device operates to switch between a viewing angle control mode and a shared mode, wherein in the area of ​​the viewing angle control panel corresponding to the boundary area, the amount of polarized light from the light source of the display device blocked by the viewing angle control panel decreases gradually from the viewing angle control area toward the shared area.

Description

Technical Field

[0001] The present invention relates to a viewing angle conversion display device.

Background Art

[0002] Generally, display devices are not only used in portable electronic devices such as mobile communication terminals, electronic notebooks, e-books, portable multimedia players (PMPs), navigation devices, ultra-mobile personal computers (UMPCs), mobile phones, smartphones, tablet personal computers (PCs), etc., but also widely used as display screens for various products such as televisions, notebook personal computers, monitors, and automated teller machines (ATMs) in banks.

[0003] For such display devices, viewing angle characteristics are very important. It is desirable for the display device to reproduce a clear and distortion-free image quality even in a wide viewing angle range. Therefore, wide viewing angle technologies have been developed. However, when it is desired that the information displayed through the display device is not visible to others located around, in addition to the wide viewing angle mode (normal mode), it is necessary to enable only the person sitting in front of the screen to view the video on the screen, for example, when working on confidential documents or performing tasks that require maintaining security. In such cases, a narrow viewing angle mode (privacy mode) is also required.

[0004] On the other hand, recently, the demand for display devices that mix the wide viewing angle mode and the narrow viewing angle mode has been increasing. There are some display devices that divide the information or area displayed on the display device and display specific areas or specific information in the narrow viewing angle mode and display other areas or information in the wide viewing angle mode. In such cases, a problem may arise that the heterogeneity at the boundary area displayed in the two modes degrades the display quality.

Summary of the Invention

[0005] The problem that this disclosure aims to solve is to provide a viewing angle switching display device that allows switching between privacy mode and general mode (or shared mode), and in particular improves brightness in shared mode without increasing power consumption.

[0006] Another problem that this disclosure seeks to solve is to provide a viewing angle switching display device that can improve image quality by minimizing the sense of alienation caused by the difference between modes displayed in the area between privacy mode and sharing mode.

[0007] Another problem that this disclosure aims to solve is to provide a viewing angle conversion display device that improves efficiency and processability.

[0008] The issues addressed in this disclosure are not limited to those mentioned above, and other issues not mentioned can be clearly understood by those skilled in the art from the following description. [Means for solving the problem]

[0009] A viewing angle switching display device according to one embodiment of the present disclosure includes a display panel including a display area and a non-display area surrounding the display area, and a viewing angle control panel disposed below the display panel and selectively controlling the operating mode of the display device by controlling polarized light transmitted to the display area, wherein the display area includes a viewing angle control area on which the display device operates to switch between a viewing angle control mode and a shared mode, a shared area on which the display device operates in a shared mode, and a boundary area disposed between the viewing angle control area and the shared area on which the display device operates to switch between a viewing angle control mode and a shared mode, and the viewing angle control panel may be configured such that in the area corresponding to the boundary area, the amount of polarized light from the light source of the display device blocked by the viewing angle control panel gradually decreases from the viewing angle control area toward the shared area.

[0010] A viewing angle conversion display device according to another embodiment of the present disclosure includes a display panel including a display area and a non-display area surrounding the display area, and a viewing angle control panel disposed below the display panel for selectively controlling the operating mode of the display device, wherein the display area includes a viewing angle control area that is converted between a viewing angle control mode and a shared mode, a shared area that operates in shared mode, and a boundary area between the viewing angle control area and the shared area, wherein the viewing angle control panel includes a first polarizing plate, a viewing angle control layer disposed on the first polarizing plate, and a second polarizing plate disposed on the viewing angle control layer and having a transmission axis perpendicular to the transmission axis of the first polarizing plate, wherein the viewing angle control layer includes a plurality of upper electrodes, at least one lower electrode, and a liquid crystal layer disposed between the upper electrode and the lower electrode, wherein in the area of ​​the viewing angle control panel corresponding to the boundary area, the width of each of the plurality of upper electrodes may be configured to gradually decrease from the viewing angle control area toward the shared area.

[0011] A viewing angle switching display device according to yet another embodiment of the present disclosure includes a display panel including a display area and a non-display area surrounding the display area, and a viewing angle control panel disposed below the display panel for selectively controlling the operating mode of the display device, wherein the display area includes a viewing angle control area that is switched between a viewing angle control mode and a shared mode, a shared area that operates in shared mode, and a boundary area between the viewing angle control area and the shared area, wherein the viewing angle control panel includes a first polarizing plate, a viewing angle control layer disposed on the first polarizing plate, and a second polarizing plate disposed on the viewing angle control layer and having a transmission axis perpendicular to the transmission axis of the first polarizing plate, wherein the viewing angle control layer includes a plurality of upper electrodes, at least one lower electrode, and a liquid crystal layer disposed between the upper electrode and the lower electrode, wherein in the region of the viewing angle control panel corresponding to the boundary area, a voltage can be applied such that the voltage applied to the plurality of upper electrodes in the viewing angle control mode gradually decreases from the viewing angle control area toward the shared area.

[0012] Specific details of other embodiments are included in the detailed description and drawings. [Effects of the Invention]

[0013] This disclosure enables switching between privacy mode and shared mode by controlling the polarization state and optical path of the light source, and provides a viewing angle switching display device that improves brightness in shared mode without increasing power consumption.

[0014] This disclosure provides a viewing angle switching display device that improves the speed of switching between privacy mode and shared mode by using a twisted nematic (TN) liquid crystal with a fast response speed for controlling the optical path.

[0015] This disclosure provides a field of view conversion display device that improves efficiency and processability by using a pixel lens to focus light and using glass as a base substrate.

[0016] The effects relating to this disclosure are not limited to those exemplified above, and a wider variety of effects are included within the present invention. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic diagram showing a field of view conversion display device according to an embodiment of the present invention. [Figure 2] This figure illustrates an exemplary viewing angle conversion display device according to an embodiment of the present invention. [Figure 3a] This is a cross-sectional view illustrating a part of a viewing angle conversion display device according to a first embodiment of the present invention. [Figure 3b] This is a cross-sectional view illustrating a part of a viewing angle conversion display device according to a first embodiment of the present invention. [Figure 4a] This is a plan view illustrating a part of a viewing angle conversion display device according to the first embodiment of the present invention. [Figure 4b] This is a plan view illustrating a part of a viewing angle conversion display device according to the first embodiment of the present invention. [Figure 5] This is an illustrative cross-sectional view showing a part of a viewing angle conversion display device according to a second embodiment of the present invention. [Figure 6a] FIG. 5 is a diagram showing a state in which the viewing angle conversion display device according to the second embodiment of the present invention is in a shared mode. [Figure 6b] FIG. 5 is a diagram showing a state in which the viewing angle conversion display device according to the second embodiment of the present invention is in a privacy mode. [Figure 7] It is a plan view of the viewing angle control region, the shared region, and the boundary region between the two regions of the display device. [Figure 8a] FIG. 7 is a schematic cross-sectional view of the viewing angle control panel along line A to A'. [Figure 8b] FIG. 7 is a schematic cross-sectional view of the viewing angle control panel along line A to A'. [Figure 9a] FIG. 7 is a schematic cross-sectional view for explaining another configuration of the viewing angle control panel along line A to A'. [Figure 9b] FIG. 7 is a schematic cross-sectional view for explaining another configuration of the viewing angle control panel along line A to A'.

MODE FOR CARRYING OUT THE INVENTION

[0018] The advantages, features, and the methods for achieving them of the present invention will become clear by referring to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and is configured in various different shapes. Simply, these embodiments are provided to make the disclosure of the present invention complete and to fully inform those with ordinary knowledge in the technical field to which the present invention pertains of the scope of the invention.

[0019] The shapes, areas, ratios, angles, numbers, etc. disclosed in the drawings illustrating embodiments of the present invention are illustrative; therefore, the present invention is not limited to those illustrated. Throughout the specification, the same reference numerals refer to the same components. Furthermore, when describing the present invention, if it is determined that a specific description of related prior art would unnecessarily obscure the gist of the invention, such detailed description will be omitted. Where "includes," "has," "is made," etc., as mentioned in the present invention, other parts may be added unless "only" is used. When a component is expressed singly, it includes cases where it includes multiple components unless otherwise explicitly stated.

[0020] When interpreting the constituent elements, they shall be interpreted as including a margin of error, even if not explicitly stated otherwise.

[0021] When describing a spatial relationship, for example, when describing the positional relationship between two parts using phrases like "on top," "above," "below," or "next to," it is acceptable for one or more other parts to be located between the two parts, as long as "immediately" or "directly" is not used.

[0022] When an element or layer is referred to as "on" another element or layer, this includes cases where another layer or other element is interposed immediately above or between the other element.

[0023] Furthermore, while terms such as "first," "second," etc., are used to describe a variety of components, these components are not limited by these terms. These terms are simply used to distinguish one component from another. Therefore, the first component referred to below may be the second component within the technical concept of the present invention.

[0024] Throughout the specification, the same reference numerals refer to the same components. The area and thickness of each component shown in the drawings are provided for illustrative purposes only, and the invention is not necessarily limited to the area and thickness of the components shown.

[0025] The features of each of the various embodiments of the present invention can be combined or linked together, either partially or entirely, enabling a wide range of technical interdependencies and drives. Each embodiment may be implemented independently of the others or together in relation to them.

[0026] The present invention will be described below with reference to the drawings.

[0027] Figure 1 is a schematic diagram showing a viewing angle conversion display device according to an embodiment of the present invention.

[0028] Figure 2 is a diagram illustrating an example of a viewing angle conversion display device according to an embodiment of the present invention.

[0029] In Figure 1, for the sake of explanation, only the display panel 110, gate drive unit GD, data drive unit DD, and timing controller TC are shown among the various components of the viewing angle conversion display device 100.

[0030] Referring to Figure 1, the viewing angle conversion display device 100 of the embodiment of the present invention may include a display panel 110 including a plurality of subpixels SP, a gate drive unit GD and a data drive unit DD and a timing controller TC that supply various signals to the display panel 110.

[0031] The gate drive unit GD can supply multiple scan signals to multiple scan wirings SL using multiple gate control signals provided by the timing controller TC. In Figure 1, one gate drive unit GD is shown to be spaced apart on one side of the display panel 110, but the number and arrangement of gate drive units GD are not limited to this.

[0032] The data drive unit DD can convert video data input from the timing controller TC into data voltage using a reference gamma voltage, based on multiple data control signals provided by the timing controller TC. The data drive unit DD can then supply the converted data voltage to multiple data wirings DL.

[0033] The timing controller TC can align externally input video data and supply it to the data drive unit DD. The timing controller TC can generate gate control signals and data control signals using externally input synchronization signals, such as dot clock signals, data enable signals, and horizontal / vertical synchronization signals. The timing controller TC can then control the gate drive unit GD and the data drive unit DD by supplying the generated gate control signals and data control signals to the gate drive unit GD and the data drive unit DD, respectively.

[0034] The display panel 110 is configured to display images to the user and may include multiple sub-pixels SP. Multiple scan lines SL and multiple data lines DL intersect each other in the display panel 110, and each of the multiple sub-pixels SP may be connected to the scan lines SL and data lines DL. In addition, each of the multiple sub-pixels SP may be connected to high-potential power lines, low-potential power lines, reference lines, etc., but is not limited to these.

[0035] The display panel 110 may have a display area AA and a non-display area NA surrounding the display area AA defined.

[0036] Display area AA is the area on the display panel 110 where the video is displayed.

[0037] The display area AA may contain multiple subpixels SP that constitute multiple pixels and circuits for driving the multiple subpixels SP. The multiple subpixels SP are the smallest units that constitute the display area AA, and n subpixels SP can form a single pixel. The display panel 110 used in the embodiment of the present invention may be any form of display panel, such as a liquid crystal display panel, an organic electroluminescent display panel, a quantum dot display panel, and an electroluminescent display panel.

[0038] Multiple wirings for transmitting various signals to multiple sub-pixels SP may be arranged in the display area AA. For example, the multiple wirings may include multiple data wirings DL that supply data voltage to each of the multiple sub-pixels SP, and multiple scan wirings SL that supply scan signals to each of the multiple sub-pixels SP. Multiple scan wirings SL may extend from the display area AA in one direction and be connected to the multiple sub-pixels SP, and multiple data wirings DL may extend from the display area AA in directions other than one direction and be connected to the multiple sub-pixels SP. In addition, low-potential power supply wiring, high-potential power supply wiring, etc., may be further arranged in the display area AA, but are not limited to these.

[0039] The non-display area NA is an area where the image is not displayed. The non-display area NA can be defined as an area extending from the display area AA. Link wiring and pad electrodes for transmitting signals to the subpixels SP of the display area AA, as well as drive ICs such as gate driver ICs and data driver ICs, may be placed in the non-display area NA.

[0040] However, the non-display area NA may be located on the back of the display panel 110, i.e., on the side without subpixels SP, or may be omitted altogether, and is not limited to what is shown in the drawing.

[0041] On the other hand, drive units such as the gate drive unit GD, data drive unit DD, and timing controller TC can be connected to the display panel 110 in various ways. For example, the gate drive unit GD can be mounted in the non-display area NA using the GIP (Gate In Panel) method. The data drive unit DD and timing controller TC can be formed on separate flexible film and printed circuit boards, and the flexible film and printed circuit board can be bonded to pad electrodes formed in the non-display area NA of the display panel 110 to electrically connect the data drive unit DD and timing controller TC to the display panel 110.

[0042] On the other hand, referring to Figure 2, the viewing angle conversion display device 100 of the present invention may include a display panel 110 for displaying images at a large size, a viewing angle control panel 120 positioned above or below the display panel 110 for selectively controlling the viewing angle range in which the image reproduced through the display panel 110 is displayed, and a backlight unit 130 located below the viewing angle control panel 120.

[0043] Figure 2 shows an example where the viewing angle control panel 120 is located below the display panel 110, but the system is not limited to this, and the viewing angle control panel 120 may be located above the display panel 110.

[0044] On the other hand, for example, if the display panel 110 is composed of a liquid crystal display panel, the display panel 110 may include a first substrate and a second substrate, and a liquid crystal layer interposed between the first substrate and the second substrate.

[0045] Although not shown in the figures, the first substrate, which is a TFT array substrate, may include gate lines and data lines that intersect each other to define pixel regions, and thin-film transistors formed at the intersections of the gate lines and data lines.

[0046] Furthermore, for example, an image can be displayed by arranging multiple common electrodes and multiple pixel electrodes alternately in the pixel region of the first substrate.

[0047] Furthermore, the second substrate, which is a color filter substrate, may have a black matrix with an aperture corresponding to each pixel region, and a color filter layer containing red, green, and blue color filters arranged in a sequential, repeating pattern corresponding to these apertures.

[0048] An overcoat layer may be placed above the black matrix and color filter layers.

[0049] Furthermore, lower polarizers and upper polarizers that selectively transmit specific light may be attached to the outer surfaces of the first and second substrates, respectively. For convenience of explanation, the lower polarizer and upper polarizer may be referred to as the third polarizer and the fourth polarizer, respectively.

[0050] In this case, the polarization axes of the third polarizer and the fourth polarizer can be orthogonal to each other.

[0051] On the other hand, a viewing angle control panel 120 may be placed above or below the display panel 110. For example, the viewing angle control panel 120 of the present invention may broadly include a viewing angle control layer and polarizing plates placed above and below the viewing angle control layer. The viewing angle control panel 120 can selectively provide light suitable for privacy mode or sharing mode by controlling the polarization state of light in different regions depending on whether or not a voltage is applied to the electrodes provided in the viewing angle control layer.

[0052] Furthermore, a backlight unit 130 may be positioned below the viewing angle control panel 120. For example, the backlight unit 130 of the present invention can provide polarized (e.g., P-wave or S-wave) light.

[0053] The backlight unit 130 includes a light source such as an incandescent lamp, a fluorescent lamp, or a light-emitting diode (LED), and an image can be reproduced by the light emitted from the light source being supplied to the display panel 110 via the viewing angle control panel 120.

[0054] The viewing angle control panel 120 and the backlight unit 130 will be described in detail below with reference to Figures 3a, 3b, 4a, and 4b.

[0055] Figures 3a and 3b are illustrative cross-sectional views showing a part of a viewing angle conversion display device according to the first embodiment of the present invention.

[0056] Figures 4a and 4b are illustrative plan views showing a part of a viewing angle conversion display device according to the first embodiment of the present invention.

[0057] Figures 3a and 3b illustrate the structure of a viewing angle control panel 120 and a backlight unit 130 according to a first embodiment of the present invention.

[0058] For the sake of explanation, Figures 3a and 3b show a part of the viewing angle conversion display device with the display panel omitted, and the display panel may be positioned above or below the viewing angle control panel 120, or attached in an add-on form.

[0059] Figure 3a shows the viewing angle conversion display device with no voltage applied to the pair of electrodes 125a and 125b, while Figure 3b shows the viewing angle conversion display device with voltage applied to the pair of electrodes 125a and 125b.

[0060] Figures 3a and 3b show the change in the polarization state of light with and without voltage application.

[0061] Figures 4a and 4b also show the arrangement of the pair of electrodes 125a and 125b.

[0062] Referring to Figures 3a and 3b and Figures 4a and 4b, a backlight unit 130 may be positioned below the viewing angle control panel 120.

[0063] The backlight unit 130 according to the first embodiment of the present invention can provide light polarized to, for example, P-wave or S-wave by applying a polarizing light source.

[0064] According to conventional technology, unpolarized light emitted from a light source is first polarized using a lower polarizer, the direction of the polarized light is controlled using a liquid crystal layer, and then the image is displayed by second polarization using an upper polarizer. Thus, conventional technology utilizes first polarized light using a lower polarizer, so most of the light emitted from the light source (about 50%) is blocked and lost by the lower polarizer. As the light passes through various films and many layers, including the polarizers, the light that displays the final image accounts for less than 10% of the total light.

[0065] On the other hand, a reflective polarizing DBEF film (Vikuiti) is used to reduce light loss and decrease overall power consumption. TM Dual Brightness Enhancement Film (DBEF) has been developed and is in use. A reflective polarized DBEF film allows light with polarization in one direction (e.g., P-waves) to pass through, while reflecting light with polarization in the other direction (e.g., S-waves). Furthermore, the light reflected by the reflective polarized DBEF film is back-reflected by the reflective film, and the DBEF film allows light with polarization in one direction to pass through, while reflecting light with polarization in the other direction again. In other words, a reflective polarized DBEF film can increase the efficiency of light utilization by utilizing both reflection and polarization. However, since light loss occurs when light is reflected, there is a limit to how much light loss a DBEF film can reduce. Another disadvantage of reflective polarized DBEF films is their high manufacturing cost.

[0066] Therefore, the first embodiment of the present invention utilizes a backlight unit 130 to which a polarizing light source is applied, thereby reducing light loss and lowering the overall power consumption of the viewing angle conversion display device. It also enables the display of an image without using a lower polarizing film and / or a reflective polarizing DBEF film, thus providing a cost-saving effect.

[0067] For example, the backlight unit 130 may include non-polar LEDs as the light source. The backlight unit 130 may also further include a diffuser and a brightness enhancement film (BEF) for mixing the light emitted from the light source, but is not limited thereto.

[0068] For example, LEDs can be aligned on top of a substrate such as a printed circuit board to form an array, and may include red, green, and blue LEDs or white LEDs. These LEDs can be regularly arranged on top of the printed circuit board to constitute an LED module, and multiple LED modules may be used to supply light to the viewing angle control panel 120. For example, a reflective film can be positioned below the light-emitting surface of the LED to reflect the light emitted from the LED upwards. The LEDs may also be supplied in the form of a package with a non-polar light-emitting diode chip.

[0069] After being emitted from the LED, the light polarized to P-waves or S-waves that has passed through the diffuser plate and BEF comes into contact with the viewing angle control panel 120. Figures 3a and 3b show an example where light polarized to P-waves is incident on the viewing angle control panel 120, but the system is not limited to this, and light polarized to S-waves may also be incident on the viewing angle control panel 120.

[0070] Generally, polarizing plates used in liquid crystal display panels require a polarization degree of 98-100%, which limits the transmittance to approximately 40-50%. However, in this invention, for example, a polarizing plate with a polarization degree of 70-90% and a transmittance of 60-80% can be used as the lower polarizing plate of the viewing angle control panel 120.

[0071] Next, the viewing angle control panel 120 according to the first embodiment of the present invention may broadly include a viewing angle control layer 129 and a first polarizing plate 122a and a second polarizing plate 122b, which are arranged below and above the viewing angle control layer 129, respectively.

[0072] For example, the first polarizer 122a may have a transmission axis that coincides with the polarization direction of the backlight light. For example, if the backlight light has horizontal polarization of the P wave, the first polarizer 122a may have a transmission axis of 0° and an absorption axis of 90°.

[0073] For example, the second polarizer 122b may have a transmission axis perpendicular to the polarization direction of the backlight light. For example, if the backlight light has horizontal polarization of the P wave, the second polarizer 122b may have a transmission axis of 90° and an absorption axis of 0°. That is, the transmission axis of the second polarizer 122b may be perpendicular to the transmission axis of the first polarizer 122a.

[0074] For reference, a polarizing plate includes a polarizing film having polarizing properties, and the polarizing film can be formed by adsorbing iodine or a dichroic dye onto a polyvinyl alcohol (PVA) layer stretched in a specific direction. In this case, a transmission axis can be formed in a direction perpendicular to the stretching direction.

[0075] For example, a first TAC (Tri Acetate Cellulose) layer 121a and a second TAC layer 121b may be placed outside the first polarizing plate 122a and the second polarizing plate 122b, respectively. Furthermore, an adhesive layer may be placed outside the second TAC layer 121b. The adhesive layer is made of an adhesive that allows the viewing angle control panel 120 to adhere to the display panel. For example, the adhesive layer may include a pressure-sensitive adhesive (PSA).

[0076] For example, a first phase delay compensation film 123a with 0RT may be placed between the first polarizing plate 122a and the viewing angle control layer 129, but is not limited to this and may be omitted in some cases.

[0077] Furthermore, for example, a first protective layer 124a may be placed between the first phase delay compensation film 123a and the viewing angle control layer 129, but is not limited to this and may be omitted in some cases. For example, the first protective layer 124a may be placed to protect the lower electrode 125a from moisture. -3 -10 -2 g / m 2 It may, but is not limited to, a silicon nitride having a water vapor transmission rate (WVTR) of 1 day.

[0078] For example, a second phase delay compensation film 123b with a value of 0RT may be placed between the second polarizing plate 122b and the viewing angle control layer 129, but is not limited to this and may be omitted in some cases.

[0079] Furthermore, for example, a second protective layer 124b may be placed between the second phase delay compensation film 123b and the viewing angle control layer 129, but is not limited to this and may be omitted in some cases. For example, the second protective layer 124b may be placed to protect the upper electrode 125b from moisture. -3 -10 -2 g / m 2 It may, but is not limited to, a silicon nitride having a WVTR of day.

[0080] Furthermore, the viewing angle control layer 129 may include a liquid crystal layer 126 disposed between the lower electrode 125a and the upper electrode 125b, and between the lower electrode 125a and the upper electrode 125b.

[0081] In this case, for example, the lower electrode 125a may be configured as a continuous electrode across the display area AA, but is not limited thereto. For example, the lower electrode 125a may extend into the non-display area NA and overlap with a portion of the non-display area NA.

[0082] In contrast, the upper electrode 125b can be configured, for example, as a plurality of bar shapes (rod-shaped) aligned in one direction across the display area AA, but is not limited thereto. Figure 4a shows an example where the upper electrode 125b is arranged in the direction aligned with the data lines, and Figure 4b shows an example where the upper electrode 125b is arranged in the direction aligned with the gate lines, but is not limited thereto. Here, the direction aligned does not only mean the same direction, but also substantially the same direction, that is, the same direction considering process errors. Furthermore, as in Figure 4a, when the upper electrode 125b is arranged in the direction aligned with the data lines, a privacy mode can be realized in the left-right direction, and as in Figure 4b, when the upper electrode 125b is arranged in the direction aligned with the gate lines, a privacy mode can be realized in the up-down direction.

[0083] Furthermore, for example, the upper electrode 125b may be configured as a plurality of bars arranged at regular intervals.

[0084] The upper electrode 125b and the lower electrode 125a may be composed of at least one of the following transparent conductive materials with excellent transmittance: indium tin oxide (ITO), indium zinc oxide (IZO), carbon nanotubes, metal nanowires, and polyethylene dioxide (Poly(3,4-ethylenedioxythiophene); PEDOT).

[0085] On the other hand, the liquid crystal layer 126 may be composed of twisted nematic (TN) liquid crystal with a fast response speed.

[0086] In twisted nematic liquid crystals, molecules are arranged in a helical configuration, and the orientation of the molecules rotates from layer to layer, which can result in the formation of an overall rotated helical structure.

[0087] Furthermore, in torsion nematic liquid crystals, the rotation of the liquid crystal molecules changes when a voltage is applied, and such molecular rotation can be used to control the transmittance of light. For example, when no voltage is applied, the helical structure causes light to rotate, and the direction of propagation of transmitted light can change.

[0088] As a result, when no electric field is applied between the upper electrode 125b and the lower electrode 125a, as shown in Figure 3a, the state of the liquid crystal layer 126 becomes the same in all regions of the viewing angle control layer 129.

[0089] In contrast, when an electric field is applied between the upper electrode 125b and the lower electrode 125a, as shown in Figure 3b, the state of the liquid crystal layer 126 becomes different between the region where the upper electrode 125b is located and the region where the upper electrode 125b is not located.

[0090] First, when no electric field is applied between the upper electrode 125b and the lower electrode 125a, as shown in Figure 3a, for example, backlight light having horizontal polarization of the P wave will be incident on the viewing angle control panel 120.

[0091] In this case, the first polarizing plate 122a has a transmission axis that coincides with the polarization direction of the backlight light, so that the P-wave backlight light is transmitted through the first polarizing plate 122a without loss.

[0092] Furthermore, in this case, the state of the liquid crystal layer 126 can be arranged identically in all regions of the viewing angle control layer 129. That is, as the liquid crystal molecules of the liquid crystal layer 126 rotate into a helical structure, the direction of propagation of light transmitted through the first polarizing plate 122a rotates, causing the polarization direction of P-wave light to change to S-wave.

[0093] In this case, the light whose polarization direction has changed to S-wave will pass through the second polarizer 122b, which has a transmission axis perpendicular to the polarization direction of the backlight light, without loss.

[0094] Therefore, in both the region where the upper electrode 125b is located and the region where the upper electrode 125b is not located, light with its polarization direction changed to S-wave passes through the viewing angle control panel 120 and is supplied to the display panel, thereby realizing a shared mode.

[0095] Next, when an electric field is applied between the upper electrode 125b and the lower electrode 125a, as shown in Figure 3b, backlight light having horizontal polarization of the P wave, as described above, will be incident on the viewing angle control panel 120.

[0096] In this case, the first polarizing plate 122a has a transmission axis that coincides with the polarization direction of the backlight light, so that the P-wave backlight light is transmitted through the first polarizing plate 122a without loss.

[0097] In contrast, in this case, the liquid crystal layer 126 can be arranged such that the state of the liquid crystal layer 126 differs between the region where the upper electrode 125b is placed and the region where the upper electrode 125b is not placed. That is, in the region where the upper electrode 125b is not placed, the liquid crystal molecules of the liquid crystal layer 126 maintain a state of rotation in a helical structure, so that the direction of propagation of light transmitted through the first polarizing plate 122a rotates and the polarization direction of P-wave light changes to S-wave. In contrast, in the region where the upper electrode 125b is placed, the liquid crystal molecules of the liquid crystal layer 126 are rearranged by the electric field, the helical pattern is released and they are aligned in a single line. As a result, P-wave light passes through the TN liquid crystal layer 126 without a change in polarization state.

[0098] Furthermore, in this case, P-wave light will not be able to pass through the second polarizer 122b, which has a transmission axis perpendicular to the polarization direction of the backlight light.

[0099] Therefore, in areas where the upper electrode 125b is not present, the polarization direction is changed to S-wave, and the light passes through the viewing angle control panel 120 and is supplied to the display panel. In contrast, in areas where the upper electrode 125b is present, P-wave light is blocked by the second polarizer 122b, thereby realizing a privacy mode.

[0100] For example, when P-wave backlight light passes through the first polarizing plate 122a, some is absorbed and about 90% is transmitted, and when it passes through the viewing angle control layer 129, some is absorbed and about 80% is transmitted. When the polarization direction of the light is changed to S-wave, some is absorbed when it passes through the second polarizing plate 122b, and ultimately about 70% can be transmitted. In contrast, P-wave light is almost completely blocked by the second polarizing plate 122b, and about 1% can be transmitted.

[0101] In contrast, with existing TFS (Thin Film Shutter) systems using an unpolarized backlight source and EC (Electrochromic), a considerable amount of light is absorbed through the color-changing elements (Electrochromic films), and only about 35% is transmitted. As a result, in the first embodiment of the present invention, an improvement in viewing brightness of approximately 3.6 times compared to existing systems can be expected.

[0102] Thus, in the first embodiment of the present invention, it is possible to switch between privacy mode and shared mode by controlling the polarization state and light path of the backlight source, and in particular, it becomes possible to provide a viewing angle switching display device that improves brightness without increasing power consumption in shared mode.

[0103] Furthermore, by using a TN liquid crystal with a fast response speed for controlling the optical path, it becomes possible to provide a viewing angle switching display device with improved switching speed between shared mode and private mode.

[0104] On the other hand, the present invention can improve efficiency by concentrating light by adding a pixel lens to the upper layer of the viewing angle control panel, and this will be explained in detail through a second embodiment of the present invention.

[0105] Figure 5 is an illustrative cross-sectional view showing a part of a viewing angle conversion display device according to a second embodiment of the present invention.

[0106] Figure 6a shows the state in which the viewing angle conversion display device according to the second embodiment of the present invention shown in Figure 5 is in shared mode.

[0107] Figure 6b shows the viewing angle conversion display device according to the second embodiment of the present invention shown in Figure 5 in privacy mode.

[0108] Figure 5 illustrates the structure of the viewing angle control panel 220 and backlight unit 130 according to a second embodiment of the present invention. Figures 6a and 6b also illustrate the structure of the viewing angle conversion display device according to a second embodiment of the present invention, namely the viewing angle control panel 220, backlight unit 130, and display panel 210.

[0109] Figure 6a shows the viewing angle conversion display device with no voltage applied to the pair of electrodes 125a and 125b, while Figure 6b shows the viewing angle conversion display device with voltage applied to the pair of electrodes 125a and 125b.

[0110] Figures 6a and 6b show the state of light propagation at a specific point with and without applied voltage. Specifically, they show the state of light propagation in front of the display panel 210 as an example.

[0111] Figures 5, 6a, and 6b have substantially the same configuration as the first embodiment of the present invention shown in Figures 3a and 3b and 4a and 4b, except that a pixel lens 228 is added to the upper layer of the viewing angle control panel 220 and a display panel 210 is placed on top of the viewing angle control panel 220. Accordingly, the same reference numerals are used for the same components, and their descriptions are omitted.

[0112] In the following explanation, the case in which the display panel 210 is configured as a liquid crystal display panel is used as an example, but the explanation is not limited to this.

[0113] Referring to Figures 5, 6a, and 6b, a display panel 210 may be positioned at the top of the viewing angle control panel 120, and a backlight unit 130 may be positioned at the bottom.

[0114] The backlight unit 130 according to the second embodiment of the present invention can provide light polarized to, for example, P-wave or S-wave by applying a polarizing light source.

[0115] The backlight unit 130 according to the second embodiment of the present invention is identical to the backlight unit 130 according to the first embodiment of the present invention described above, and therefore its description is omitted.

[0116] In the display panel 210 of the second embodiment of the present invention, an array substrate 212a and a color filter substrate 212b are separated from each other and facing each other, and a liquid crystal layer 213 may be interposed between the array substrate 212a and the color filter substrate 212b. Here, for the sake of explanation, the array substrate 212a and the color filter substrate 212b may be referred to as the first substrate and the second substrate, respectively.

[0117] The first substrate 212a may include gate lines and data lines that intersect with each other to define a pixel region, and thin-film transistors of switching elements formed at the intersections of the gate lines and data lines.

[0118] Furthermore, for example, an image can be displayed by arranging multiple common electrodes and multiple pixel electrodes alternately in the pixel region of the first substrate 212a.

[0119] Furthermore, the second substrate 212b may have a black matrix (not shown) having an aperture corresponding to each pixel region, and a color filter layer 214 including red, green, and blue color filters arranged in a sequential, repeating pattern corresponding to these apertures may be arranged thereon.

[0120] An overcoat layer (not shown) may be placed above the black matrix and the color filter layer 214.

[0121] Furthermore, a lower polarizing plate 211a and an upper polarizing plate 211b may be attached to the outer surfaces of the first substrate 212a and the second substrate 212b, respectively. For the sake of explanation, the lower polarizing plate 211a and the upper polarizing plate 211b may be referred to as the third polarizing plate and the fourth polarizing plate, respectively.

[0122] In this case, the polarization axes of the third polarizer 211a and the fourth polarizer 211b can be orthogonal to each other.

[0123] As mentioned above, the P-wave or S-wave backlight light emitted through the backlight unit 130 is incident on the viewing angle control panel 220. Figures 6a and 6b show an example where P-wave polarized backlight light is incident on the viewing angle control panel 220, but the system is not limited to this, and S-wave polarized backlight light may also be incident on the viewing angle control panel 220.

[0124] Next, the viewing angle control panel 220 according to the second embodiment of the present invention may broadly include a viewing angle control layer 129 and a first polarizing plate 122a and a second polarizing plate 122b, which are arranged below and above the viewing angle control layer 129, respectively. Furthermore, the viewing angle control panel 220 according to the second embodiment of the present invention may further include a pixel lens 228 arranged above the second polarizing plate 122b.

[0125] For example, the first polarizer 122a may have a transmission axis that coincides with the polarization direction of the backlight light. For example, if the backlight light has horizontal polarization of the P wave, the first polarizer 122a may have a transmission axis of 0° and an absorption axis of 90°.

[0126] For example, the second polarizer 122b may have a transmission axis perpendicular to the polarization direction of the backlight light. For example, if the backlight light has horizontal polarization of the P wave, the second polarizer 122b may have a transmission axis of 90° and an absorption axis of 0°. That is, the transmission axis of the second polarizer 122b may be perpendicular to the transmission axis of the first polarizer 122a.

[0127] For example, a first TAC layer 121a and a second TAC layer 121b may be placed on the outside of the first polarizing plate 122a and the second polarizing plate 122b, respectively. Furthermore, an adhesive layer may be placed on the outside of the second TAC layer 121b. For example, the adhesive layer may include a pressure-sensitive adhesive.

[0128] For example, a first phase delay compensation film 123a with 0RT may be placed between the first polarizing plate 122a and the viewing angle control layer 129, but is not limited to this and may be omitted in some cases.

[0129] Furthermore, for example, a first protective layer 124a may be placed between the first phase delay compensation film 123a and the viewing angle control layer 129, but is not limited to this and may be omitted in some cases.

[0130] For example, a second phase delay compensation film 123b with a value of 0RT may be placed between the second polarizing plate 122b and the viewing angle control layer 129, but is not limited to this and may be omitted in some cases.

[0131] Furthermore, for example, a second protective layer 124b may be placed between the second phase delay compensation film 123b and the viewing angle control layer 129, but is not limited to this and may be omitted in some cases.

[0132] Furthermore, the viewing angle control layer 129 may include a liquid crystal layer 126 disposed between the lower electrode 125a and the upper electrode 125b, and between the lower electrode 125a and the upper electrode 125b.

[0133] In this case, for example, the lower electrode 125a may be configured as a continuous electrode across the display area AA, but is not limited thereto. For example, the lower electrode 125a may extend into the non-display area NA and overlap with a portion of the non-display area NA.

[0134] In contrast, the upper electrode 125b may, for example, be configured as a plurality of bars arranged in one direction across the display area AA, but is not limited to this.

[0135] Furthermore, for example, the upper electrode 125b may be configured as a plurality of bars arranged at regular intervals.

[0136] The upper electrode 125b and the lower electrode 125a may be composed of at least one of the following transparent conductive materials with excellent transmittance: indium tin oxide (ITO), indium zinc oxide (IZO), carbon nanotubes, metal nanowires, and polyethylene dioxide (Poly(3,4-ethylenedioxythiophene); PEDOT).

[0137] On the other hand, the liquid crystal layer 126 may be composed of twisted nematic (TN) liquid crystal with a fast response speed.

[0138] Furthermore, as shown in Figure 6a, when no electric field is applied between the upper electrode 125b and the lower electrode 125a, the state of the liquid crystal layer 126 becomes the same in all regions of the viewing angle control layer 129.

[0139] In contrast, when an electric field is applied between the upper electrode 125b and the lower electrode 125a, as shown in Figure 6b, the state of the liquid crystal layer 126 becomes different between the region where the upper electrode 125b is located and the region where the upper electrode 125b is not located.

[0140] First, when no electric field is applied between the upper electrode 125b and the lower electrode 125a, as shown in Figure 6a, for example, backlight light having horizontal polarization of P waves will be incident on the viewing angle control panel 220. In the following, for convenience, we will examine the behavior of P-wave backlight light incident on the viewing angle control panel 220 at one point on the backlight unit 130 as an example.

[0141] In this case, the first polarizing plate 122a has a transmission axis that coincides with the polarization direction of the backlight light, so that the P-wave backlight light is transmitted through the first polarizing plate 122a without loss. For example, the P-wave backlight light incident on the viewing angle control panel 220 at one point of the backlight unit 130 can be transmitted through the first polarizing plate 122a in both the central and left-right directions.

[0142] Furthermore, in this case, the state of the liquid crystal layer 126 can be arranged identically in all areas of the viewing angle control layer 129. That is, as the liquid crystal molecules of the liquid crystal layer 126 rotate into a helical structure, the direction of propagation of light transmitted through the first polarizing plate 122a rotates, causing the polarization direction of P-wave light to change to S-wave light in both the central and left / right directions. In this case, light with its polarization direction changed to S-wave can pass through the viewing angle control panel 120 in both the area where the upper electrode 125b is located and the area where the upper electrode 125b is not located.

[0143] Furthermore, in this case, the light whose polarization direction has changed to an S-wave will pass through the second polarizer 122b, which has a transmission axis perpendicular to the polarization direction of the backlight light, without loss. For example, the backlight light traveling from the viewing angle control panel 220 to the second polarizer 122b can pass through the second polarizer 122b in both the central and left-right directions.

[0144] Furthermore, in this case, all backlight light transmitted through the second polarizing plate 122b in the central and left-right directions is provided to the display panel 210, enabling a shared mode. That is, by providing the display panel 210 with not only backlight light traveling in the central direction but also backlight light traveling in the left-right diagonal directions, it becomes possible to achieve clear, distortion-free image quality over a wide viewing angle range.

[0145] Next, when an electric field is applied between the upper electrode 125b and the lower electrode 125a, as shown in Figure 6b, backlight light having horizontal polarization of the P wave will be incident on the viewing angle control panel 120, as described above.

[0146] In this case, the first polarizing plate 122a has a transmission axis that coincides with the polarization direction of the backlight light, so that the P-wave backlight light is transmitted through the first polarizing plate 122a without loss. For example, the P-wave backlight light incident on the viewing angle control panel 220 at one point of the backlight unit 130 can be transmitted through the first polarizing plate 122a in both the central and left-right directions.

[0147] In contrast, in this case, the liquid crystal layer 126 can be arranged such that the state of the liquid crystal layer 126 differs between the region where the upper electrode 125b is located and the region where the upper electrode 125b is not located. That is, in the region where the upper electrode 125b is not located, the liquid crystal molecules of the liquid crystal layer 126 maintain a state of rotation in a helical structure, so that the direction of propagation of light transmitted through the first polarizing plate 122a rotates, and the polarization direction of P-wave light changes to S-wave. In this case, the light whose polarization direction has changed to S-wave will be transmitted without loss through the second polarizing plate 122b, which has a transmission axis perpendicular to the polarization direction of the backlight light. For example, backlight light traveling from the viewing angle control panel 220 toward the second polarizing plate 122b can be transmitted through the second polarizing plate 122b without loss.

[0148] In contrast, in the region where the upper electrode 125b is located, the electric field rearranges the liquid crystal molecules of the liquid crystal layer 126, releasing the helical pattern and aligning them in a single line. This allows P-wave light to pass through the TN liquid crystal layer 126 without a change in polarization state. In this case, P-wave light cannot pass through the second polarizing plate 122b, which has a transmission axis perpendicular to the polarization direction of the backlight light. For example, backlight light traveling from the viewing angle control panel 220 towards the second polarizing plate 122b in a left-right direction, i.e., diagonal direction, can be blocked by the second polarizing plate 122b, thereby achieving a privacy mode. That is, only a person sitting directly in front of the screen can see the image on the screen, allowing for the smooth execution of tasks such as working with confidential documents or maintaining security.

[0149] Thus, in the second embodiment of the present invention, it is possible to switch between privacy mode and shared mode by controlling the polarization state and light path of the backlight source, and in particular, it becomes possible to provide a viewing angle switching display device that improves brightness without increasing power consumption in shared mode.

[0150] Furthermore, by using a TN liquid crystal with a fast response speed for controlling the optical path, it becomes possible to provide a viewing angle switching display device with improved switching speed between shared mode and private mode.

[0151] On the other hand, the viewing angle conversion display device according to the second embodiment of the present invention may further include a pixel lens 228 arranged on top of the viewing angle control panel 220.

[0152] For example, a lens assembly may be positioned on top of the second polarizing plate 122b. For example, the lens assembly may include a plurality of pixel lenses 228 positioned on the substrate 227. The lens assembly may be located in the path of light emitted from the backlight unit 130.

[0153] The lower surface of each pixel lens 228 facing the second polarizing plate 122b may be a flat plane. The surface of each pixel lens 228 facing the display panel 210 may be semicircular, but is not limited to this. Multiple pixel lenses 228 may be positioned side by side. For example, the lens assembly may include a lenticular lens.

[0154] For example, each pixel area of ​​the display panel 210 can be superimposed on one of the pixel lenses 228. As a result, in the viewing angle conversion display device according to the second embodiment of the present invention, backlight light can pass through one of the pixel lenses 228 and be emitted to each pixel area and provided to the user. Therefore, in the viewing angle conversion display device according to the second embodiment of the present invention, the central brightness of each pixel area can be improved.

[0155] Although not shown, the lens assembly may further include a cover layer that covers the pixel lenses 228. The cover layer can prevent damage to the pixel lenses 228 from external impacts. For example, the semicircular surface of each pixel lens 228 may be completely covered by the cover layer. The cover layer can eliminate any steps caused by the pixel lenses 228. For example, the cover layer may contain an insulating material.

[0156] For example, multiple pixel lenses 228 may be arranged in a direction aligned with the data line at regular intervals, and each pixel lens 228 may be configured in the form of multiple aligned bars, but is not limited to this.

[0157] For example, each pixel lens 228 may be positioned in a region between the upper electrodes 125b, i.e., a non-pattern region.

[0158] Furthermore, for example, each pixel lens 228 may be positioned corresponding to the red, green, and blue color filters of the color filter layer 214, respectively.

[0159] Figure 7 is a plan view of the viewing angle control area, shared area, and boundary area of ​​the display device.

[0160] In the diverse environments in which users utilize display devices, it may be necessary to control the viewing angle of certain areas of the display device while leaving the viewing angle uncontrolled in other areas.

[0161] For example, in the case of a display device installed on the front of a car, the screen in the driver's seat can be viewed by both the driver and the passenger in the front seat. However, if the passenger in the front seat is watching an entertainment screen such as a video, it may interfere with the driver's driving, so the viewing angle must be controlled to prevent the driver from seeing it.

[0162] This is because images and other visual cues that draw the driver's attention while driving can hinder safe driving.

[0163] In other use cases, when a user is using a monitor, laptop, or tablet, they may not want certain content to be seen by others due to personal privacy concerns.

[0164] In addition to the situations mentioned above, there may be a variety of other usage environments, and the viewing angle control area (PA) of a display device that limits the viewing angle in these diverse usage environments may be fluid, and there may be cases where viewing angle limitation is required in a selective area.

[0165] When the viewing angle control area PA and the shared area SA are separated and driven within the display area in this way, the sense of alienation at the boundary between them may increase, which can be a factor in reducing user immersion and the display quality of the display device.

[0166] Figure 7 shows the viewing angle control area PA, the shared area SA, and the boundary area MA of the two areas within the display area AA of the display device. The viewing angle control area PA may take various forms such as a circle or a square within the display area AA, and the position of the viewing angle control area PA can also be any position inside the display area AA.

[0167] Figure 7 shows a simplified representation of the three regions described above, demonstrating that a variety of deformable embodiments are possible.

[0168] As described above, when the field of view control area PA and the shared area SA are driven to display images at different field of view angles, the boundary between the areas, which have different field of view angles depending on the viewer's position, becomes even more noticeable due to the difference in field of view angles. Below, various configurations to minimize this will be described.

[0169] Figures 8a and 8b are schematic cross-sectional views of the viewing angle control panel along A to A' in Figure 7.

[0170] Referring to Figures 8a and 8b, a method for minimizing the visual difference between the field of view control area PA and the shared area SA in the boundary area MA will be explained, and the explanation of components that are substantially the same as those described earlier will be omitted.

[0171] Figures 8a and 8b show a part of a viewing angle conversion display device with the display panel omitted, where the display panel may be positioned above or below the viewing angle control panel 120, or attached in an add-on configuration. The display panel may be a liquid crystal display panel or an organic light-emitting display panel, and if the display panel is a liquid crystal display panel, a light source such as a backlight unit may be further included below the viewing angle control panel 120. Hereinafter, the embodiments will be described based on embodiments in which a liquid crystal display panel is used as the display panel.

[0172] Referring to Figures 8a and 8b, the viewing angle control panel 120 includes a second polarizing plate 122b having a transmission axis parallel and perpendicular to the first polarizing plate 122a, and includes a viewing angle control layer 129 between the first polarizing plate 122a and the second polarizing plate 122b, the viewing angle control layer 129 includes a liquid crystal layer 126 between at least one lower electrode 125a and a plurality of upper electrodes 125b.

[0173] An orientation film may further be included on the lower electrode 125a, but a detailed description related thereto is omitted in this specification.

[0174] A first TAC (Tri Acetate Cellulose) layer 121a and a second TAC layer 121b may be placed on the outside of the first polarizing plate 122a and the second polarizing plate 122b, respectively. Furthermore, an adhesive layer may be placed on the outside of the second TAC layer 121b.

[0175] Although not shown in Figures 8a and 8b, a lens assembly may be positioned on top of the second polarizing plate 122b. For example, the lens assembly may include a plurality of pixel lenses 228 positioned on the substrate 227, as shown in Figures 6a and 6b.

[0176] The regions shown in Figures 8a and 8b are cross-sections corresponding to the boundary region MA, where boundary A is adjacent to the field of view control region PA, and boundary A' is adjacent to the shared region SA.

[0177] In the boundary region MA, the upper electrode 125b is positioned such that its width is wider the closer it is to the field of view control region PA, and relatively narrower the closer it is to the shared region SA.

[0178] On the other hand, although not shown in Figures 8a and 8b, the shared region SA does not necessarily have to include the upper electrode 125b, but is not limited to this. If necessary, an electrode made of the same material as the upper electrode 125b may be placed to minimize the visual difference between the field of view control region PA, the boundary region MA, and the shared region SA, and may be placed as a dummy electrode to which no power is applied.

[0179] If the shared region SA includes the upper electrode 125b, as described above, the upper electrode 125b may be a dummy electrode, which can minimize the luminous difference due to light reflection from external light and minimize the luminous difference due to the transmittance of light emitted from the backlight unit 130.

[0180] In various modifiable embodiments, the dummy electrode can maintain a constant voltage regardless of whether it is in viewing angle control mode or shared mode. Furthermore, the dummy electrode may extend to the outer casing of the viewing angle control panel and be connected to a ground electrode or configured to maintain a constant voltage to reduce the risk of the viewing angle control panel malfunctioning due to static electricity or the like.

[0181] The multiple upper electrodes 125b of the shared region SA are configured in a bar shape aligned in one direction, and the lower electrodes 125a may be configured in a continuous electrode shape across the display region AA, but the multiple upper electrodes 125b may be arranged in a direction aligned with the gate line, and if necessary, in a direction aligned with the data line.

[0182] The upper electrode 125b, positioned in the boundary region MA, is an electrode for realizing a privacy mode, which is oriented in a direction aligned with the gate line. The upper electrode 125b and the lower electrode 125a may be composed of at least one of the following transparent conductive materials with excellent transmittance: indium tin oxide (ITO), indium zinc oxide (IZO), carbon nanotubes, metal nanowires, and polyethylene dioxide (Poly(3,4-ethylenedioxythiophene); PEDOT).

[0183] On the other hand, the liquid crystal layer 126 may be composed of twisted nematic (TN) liquid crystal with a fast response speed.

[0184] In twisted nematic liquid crystals, molecules are arranged in a helical configuration, and the orientation of the molecules rotates from layer to layer, which can result in the formation of an overall rotated helical structure.

[0185] Furthermore, in torsion nematic liquid crystals, the rotation of the liquid crystal molecules changes when a voltage is applied, and such molecular rotation can be used to control the transmittance of light. For example, when no voltage is applied, the helical structure causes light to rotate, and the direction of propagation of transmitted light can change.

[0186] As a result, when no electric field is applied between the upper electrode 125b and the lower electrode 125a, as shown in Figure 8a, the state of the liquid crystal layer 126 becomes the same in all regions of the viewing angle control layer 129.

[0187] In contrast, when an electric field is applied between the upper electrode 125b and the lower electrode 125a, as shown in Figure 8b, the state of the liquid crystal layer 126 becomes different between the region where the upper electrode 125b is located and the region where the upper electrode 125b is not located.

[0188] The configuration will be explained by the path of light. First, as shown in Figure 8a, when no electric field is applied between the upper electrode 125b and the lower electrode 125a, backlight light having horizontal polarization of the P wave enters the viewing angle control panel 120 from the backlight unit 130.

[0189] In this case, the first polarizing plate 122a has a transmission axis that coincides with the polarization direction of the backlight light, so that the P-wave backlight light is transmitted through the first polarizing plate 122a without loss.

[0190] Furthermore, in this case, the state of the liquid crystal layer 126 can be arranged identically in all areas of the viewing angle control layer 129. In a twisted nematic liquid crystal, the molecules are arranged in a helical shape, and the liquid crystal molecules of the liquid crystal layer 126 rotate into a helical structure, causing the direction of propagation of light transmitted through the first polarizing plate 122a to rotate, and the polarization direction of P-wave light to S-wave light to change.

[0191] In this case, the light whose polarization direction has changed to S-wave will pass through the second polarizer 122b, which has a transmission axis perpendicular to the polarization direction of the backlight light, without loss.

[0192] Therefore, in both the region where the upper electrode 125b is located and the region where the upper electrode 125b is not located, light with its polarization direction changed to S-wave passes through the viewing angle control panel 120 and is supplied to the display panel, thereby realizing a shared mode.

[0193] Next, when an electric field is applied between the upper electrode 125b and the lower electrode 125a, as shown in Figure 8b, backlight light having horizontal polarization of the P wave, as described above, will be incident on the viewing angle control panel 120.

[0194] In this case, the first polarizing plate 122a has a transmission axis that coincides with the polarization direction of the backlight light, so that the P-wave backlight light is transmitted through the first polarizing plate 122a without loss.

[0195] In contrast, in this case, the liquid crystal layer 126 can be arranged such that the state of the liquid crystal layer 126 differs between the region where the upper electrode 125b is placed and the region where the upper electrode 125b is not placed. That is, in the region where the upper electrode 125b is not placed, the liquid crystal molecules of the liquid crystal layer 126 maintain a state of rotation in a helical structure, so that the direction of propagation of light transmitted through the first polarizing plate 122a rotates and the polarization direction of P-wave light changes to S-wave. In contrast, in the region where the upper electrode 125b is placed, the liquid crystal molecules of the liquid crystal layer 126 are rearranged by the electric field, the helical pattern is released and they are aligned in a single line. As a result, P-wave light passes through the TN liquid crystal layer 126 without a change in polarization state.

[0196] Furthermore, in this case, P-wave light will not be able to pass through the second polarizer 122b, which has a transmission axis perpendicular to the polarization direction of the backlight light.

[0197] Therefore, in the region where the upper electrode 125b is not present, light with its polarization direction changed to S-wave passes through the viewing angle control panel 120 and is supplied to the display panel, whereas in the region where the upper electrode 125b is present, P-wave light is blocked by the second polarizer 122b, thereby realizing a privacy mode.

[0198] As shown in Figure 8b, the upper electrodes 125b may be arranged within the boundary region MA with electrodes of different widths (or widths), such that the electrode width increases as it approaches the field of view control region PA and decreases as it approaches the shared region SA.

[0199] Thus, the upper electrodes 125b can be arranged to have different widths in the boundary region MA. For example, the first width W1 may be larger than the second width W2, the second width W2 may be larger than the third width W3, and the third width W3 may be larger than the fourth width W4.

[0200] In the configuration described above, the width of the upper electrode 125b of the boundary region MA is wider when it is closer to the viewing angle control region PA and narrower when it is closer to the shared region SA. Therefore, when driven in viewing angle control mode, the viewing angle of the light that passes through the viewing angle control panel 120 and is supplied to the display panel becomes narrower when it is closer to the viewing angle control region PA and wider when it is closer to the shared region SA.

[0201] As described above, when the upper electrodes 125b are arranged with different widths and driven in field of view limiting mode, the field of view control effect increases as they are adjacent to the field of view control region PA, and decreases as they are adjacent to the shared region SA.

[0202] In this way, the width of the upper electrode 125b corresponding to the boundary region MA gradually narrows in the direction of the shared region SA, thereby reducing the heterogeneous visual perception caused by the difference in field of view limitation between the field of view control region PA and the shared region SA.

[0203] As an effect of the above-described configuration, when the viewing angle conversion display device 100 is driven in viewing angle control mode, the sense of alienation at the boundary due to the difference in viewing angle between the viewing angle control area PA and the shared area SA can be minimized in the boundary area MA.

[0204] The following describes other configurations that can reduce the visual difference, which differ from the embodiments described above.

[0205] Figures 9a and 9b are schematic cross-sectional views illustrating other configurations of the viewing angle control panel along A to A' in Figure 7.

[0206] Referring to Figures 9a and 9b, other methods for minimizing the visual difference between the field of view control area PA and the shared area SA in the boundary area MA will be described, and configurations that are substantially the same as those described earlier will not be explained.

[0207] Figures 9a and 9b show a portion of a viewing angle conversion display device with the display panel omitted, where the display panel may be positioned above or below the viewing angle control panel 120, or attached as an add-on. If the display panel is a liquid crystal display panel, a light source such as a backlight unit may be further included below the viewing angle control panel 120. In the following embodiments, an example in which a liquid crystal display panel is used as the display panel will be described.

[0208] Referring to Figures 9a and 9b, the viewing angle control panel 120 includes a second polarizing plate 122b having a transmission axis parallel and perpendicular to the first polarizing plate 122a, and includes a viewing angle control layer 129 between the first polarizing plate 122a and the second polarizing plate 122b, the viewing angle control layer 129 includes a liquid crystal layer 126 between at least one lower electrode 125a and a plurality of upper electrodes 125b.

[0209] An orientation film may further be included on the lower electrode 125a, but a detailed description related thereto is omitted in this specification.

[0210] A first TAC (Tri Acetate Cellulose) layer 121a and a second TAC layer 121b may be placed on the outside of the first polarizing plate 122a and the second polarizing plate 122b, respectively. Furthermore, an adhesive layer may be placed on the outside of the second TAC layer 121b.

[0211] Although not shown in Figures 9a and 9b, a lens assembly may be positioned on top of the second polarizing plate 122b. For example, the lens assembly may include a plurality of pixel lenses 228 positioned on the substrate 227.

[0212] The regions shown in Figures 9a and 9b correspond to the boundary region MA, where boundary line A is adjacent to the field of view control region PA, and A' is adjacent to the shared region SA.

[0213] In the embodiment described in Figures 9a and 9b, the viewing angle control area PA and the shared area SA can be fluidly changed within the display area AA. As shown in Figure 7, they can be arranged on the left and right sides of the boundary area MA, but are not limited to this, and the viewing angle control area PA may be in the form of a rectangle, circle, or polygon within the display area AA, in which case the boundary area MA may be located at the boundary between the viewing angle control area PA and the shared area SA.

[0214] Since the field of view control region PA and the shared region SA are fluid, in this embodiment, the multiple upper electrodes 125b may have a structure in which data electrodes and gate electrodes are connected, and may be active matrix type pixel electrodes to which voltage is actively applied by the data signal and the gate electrode signal.

[0215] Referring to Figures 9a and 9b, in the case of Figure 9a, where no electric field is applied between the upper electrode 125b and the lower electrode 125a, backlight light having horizontal polarization of the P wave is incident on the viewing angle control panel 120.

[0216] In this case, the first polarizing plate 122a has a transmission axis that coincides with the polarization direction of the backlight light, so that the P-wave backlight light is transmitted through the first polarizing plate 122a without loss.

[0217] Furthermore, in this case, the state of the liquid crystal layer 126 can be arranged identically in all regions of the viewing angle control layer 129. That is, as the liquid crystal molecules of the liquid crystal layer 126 rotate into a helical structure, the direction of propagation of light transmitted through the first polarizing plate 122a rotates, causing the polarization direction of P-wave light to change to S-wave.

[0218] In this case, the light whose polarization direction has changed to S-wave will pass through the second polarizer 122b, which has a transmission axis perpendicular to the polarization direction of the backlight light, without loss.

[0219] Therefore, in both the region where the upper electrode 125b is located and the region where the upper electrode 125b is not located, light with its polarization direction changed to S-wave passes through the viewing angle control panel 120 and is supplied to the display panel, thereby realizing a shared mode.

[0220] Next, to explain the field of view control mode, we will describe the case where an electric field is applied between the upper electrode 125b and the lower electrode 125a, as shown in Figure 9b.

[0221] Backlight light having horizontal polarization of the P wave is incident on the viewing angle control panel 120. The first polarizing plate 122a has a transmission axis that matches the polarization direction of the backlight light, so that the P wave backlight light is transmitted through the first polarizing plate 122a without loss.

[0222] In the case of Figure 9b, where an electric field is applied to the upper electrode 125b, the liquid crystal layer 126 can be arranged in a way that the state of the liquid crystal layer 126 differs between the region where the upper electrode 125b is located and the region where the upper electrode 125b is not located. That is, in the region where the upper electrode 125b is not located, the liquid crystal molecules of the liquid crystal layer 126 maintain a state of rotation in a helical structure, causing the direction of propagation of light transmitted through the first polarizing plate 122a to rotate, and the polarization direction of P-wave light to change to S-wave. In contrast, in the region where the upper electrode 125b is located, the liquid crystal molecules of the liquid crystal layer 126 are rearranged by the electric field, the helical pattern is released, and they are aligned in a single line again. As a result, P-wave light passes through the TN liquid crystal layer 126 without a change in polarization state.

[0223] Furthermore, in this case, P-wave light will not be able to pass through the second polarizer 122b, which has a transmission axis perpendicular to the polarization direction of the backlight light.

[0224] Therefore, in the region where the upper electrode 125b is not present, light with its polarization direction changed to S-wave passes through the viewing angle control panel 120 and is supplied to the display panel, whereas in the region where the upper electrode 125b is present, P-wave light is blocked by the second polarizer 122b, thereby realizing a privacy mode.

[0225] In this case, the voltage of the current applied to the upper electrode 125b corresponding to the boundary region MA can be between 0V and 5V, and depending on the type of liquid crystal used in the liquid crystal layer 126 and the structure of the upper electrode 125b and the lower electrode 125a, a voltage of 5V or more may be applied.

[0226] In one embodiment of this specification, the voltage applied to the upper electrode 125b may be applied at different voltages within the boundary region MA, but the voltage can be applied such that it increases as it approaches the field of view control region PA and decreases as it approaches the shared region SA.

[0227] When the voltage applied to the upper electrode 125b is such that it gradually decreases from the field of view control region PA towards the shared region SA, the field of view control effect increases as it approaches the field of view control region PA, and decreases as it approaches the shared region SA.

[0228] The liquid crystal layer 126 can contain twisted nematic liquid crystals (TN), and when a voltage is applied to the liquid crystal layer 126, the rotation of the liquid crystal molecules changes, but the rotation of the liquid crystal molecules differs depending on the voltage difference. The transmittance of light can be controlled by this rotation of molecules.

[0229] For example, when a low voltage is applied, the change in the helical structure is small, so a relatively large amount of light incident on the P wave is converted to the S wave. This increases the transmittance where the upper electrode 125b is located, reducing the field of view control effect.

[0230] Conversely, when a progressively higher voltage is applied, the change in the helical structure becomes larger, and the amount of light incident on the P wave that is converted to the S wave becomes relatively smaller. This reduces the transmittance where the upper electrode 125b is located, thereby increasing the effect of controlling the field of view.

[0231] Figure 9b demonstrates how these features are utilized. In order to reduce the visual difference in the boundary region MA between the field of view control region PA and the shared region SA, a relatively high voltage is applied to the upper electrode 125b adjacent to the field of view control region PA, and a relatively low voltage is applied to the upper electrode 125b adjacent to the shared region SA. By gradually increasing or decreasing the voltage applied to the upper electrodes 125b in this way, the field of view limiting effect can be gradually changed, thereby minimizing the visual difference.

[0232] Thus, when applying different voltages to each other, the voltage applied to the upper electrode 125b of the boundary region MA increases as it approaches the field of view control region PA in field of view control mode, decreases as it approaches the shared region SA, and must not be greater than the voltage applied to the upper electrode 125b corresponding to the field of view control region PA, nor less than the voltage applied to the upper electrode 125b corresponding to the shared region SA.

[0233] As described above, by applying different voltages to the boundary region MA and the corresponding upper electrode 125b, the difference in perceived visual field due to the difference in field of view control effect can be minimized.

[0234] Although embodiments of the present invention have been described in more detail above with reference to the attached drawings, the present invention is not necessarily limited to these embodiments and can be modified and implemented in various ways within the scope of the technical concept of the present invention. Accordingly, the embodiments disclosed herein are for illustrative purposes only, not to limit the technical concept of the present invention, and the scope of the technical concept of the present invention is not limited by such embodiments. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. All technical concepts that fall within the scope equivalent to the claims of the present invention should be interpreted as being included in the scope of the rights of the present invention.

Claims

1. A display panel including a display area and a non-display area surrounding the display area, The display panel includes a viewing angle control panel positioned below the display panel, which selectively controls the operating mode of the display device by controlling polarized light transmitted to the display area. The display area includes a viewing angle control area in which the display device operates to switch between a viewing angle control mode and a shared mode, a shared area in which the display device operates in the shared mode, and a boundary area located between the viewing angle control area and the shared area, in which the display device operates to switch between the viewing angle control mode and the shared mode. A viewing angle conversion display device configured such that, in a region corresponding to the boundary region of the viewing angle control panel, the amount by which polarized light from the light source of the display device is blocked by the viewing angle control panel gradually decreases from the viewing angle control region toward the shared region.

2. A display panel including a display area and a non-display area surrounding the display area, The display panel includes a viewing angle control panel positioned below it for selectively controlling the operating mode of the display device, The display area includes a viewing angle control area that is switched between a viewing angle control mode and a shared mode, a shared area that operates in the shared mode, and a boundary area between the viewing angle control area and the shared area. The aforementioned viewing angle control panel is The first polarizing plate and A viewing angle control layer disposed on the first polarizing plate, It includes a second polarizing plate disposed on the viewing angle control layer and having a transmission axis perpendicular to the transmission axis of the first polarizing plate, The viewing angle control layer includes a plurality of upper electrodes, at least one lower electrode, and a liquid crystal layer disposed between the upper electrode and the lower electrode. A viewing angle conversion display device, wherein in the region corresponding to the boundary region of the viewing angle control panel, the width of each of the plurality of upper electrodes is configured to gradually decrease in the direction from the viewing angle control region to the shared region.

3. The viewing angle conversion display device according to claim 2, wherein in the region of the viewing angle control layer corresponding to the shared region, the viewing angle control layer is composed only of the lower electrode and the liquid crystal layer.

4. The viewing angle conversion display device according to claim 2, wherein in the region of the viewing angle control layer corresponding to the shared region, the upper electrode is a dummy electrode to which no power is applied.

5. The viewing angle conversion display device according to claim 4, wherein the dummy electrode is a ground electrode.

6. The aforementioned multiple upper electrodes are configured as multiple rods parallel to each other in one direction, The viewing angle conversion display device according to claim 2, wherein the lower electrode is configured in a pass-through electrode form that extends over the entire display area.

7. The viewing angle conversion display device according to claim 6, wherein the upper electrode is arranged in a direction parallel to the data line or gate line of the display device.

8. When no electric field is applied between the upper electrode and the lower electrode, the state of the liquid crystal layer remains constant throughout the entire viewing angle control layer. The viewing angle conversion display device according to claim 2, wherein when an electric field is applied between the upper electrode and the lower electrode, the state of the liquid crystal layer in the region where the upper electrode is located and the region where the upper electrode is not located are different from each other.

9. The viewing angle conversion display device according to claim 2, wherein the lower electrode extends into the non-display area and overlaps with a portion of the non-display area.

10. The viewing angle conversion display device according to any one of claims 2 to 9, further comprising a plurality of pixel lenses disposed on the upper part of the second polarizing plate.

11. The field of view angle conversion display device according to claim 10, wherein the lower surface of each pixel lens is flat and the upper surface is semicircular.

12. A display panel including a display area and a non-display area surrounding the display area, The display panel includes a viewing angle control panel positioned below it for selectively controlling the operating mode of the display device, The display area includes a viewing angle control area that is switched between a viewing angle control mode and a shared mode, a shared area that operates in the shared mode, and a boundary area between the viewing angle control area and the shared area. The aforementioned viewing angle control panel is The first polarizing plate and A viewing angle control layer disposed on the first polarizing plate, It includes a second polarizing plate disposed on the viewing angle control layer and having a transmission axis perpendicular to the transmission axis of the first polarizing plate, The viewing angle control layer includes a plurality of upper electrodes, at least one lower electrode, and a liquid crystal layer disposed between the upper electrode and the lower electrode. A viewing angle conversion display device, wherein in the region corresponding to the boundary region of the viewing angle control panel, the voltage applied to the plurality of upper electrodes in the viewing angle control mode is applied such that it gradually decreases from the viewing angle control region toward the shared region.

13. The viewing angle conversion display device according to claim 12, wherein in the region of the viewing angle control layer corresponding to the shared region, the upper electrode maintains a constant voltage regardless of the operating mode.

14. The viewing angle conversion display device according to claim 12, wherein in the region of the viewing angle control layer corresponding to the shared region, the upper electrode is a dummy electrode.

15. The viewing angle conversion display device according to claim 14, wherein the dummy electrode is a ground electrode.

16. The aforementioned multiple upper electrodes are configured as multiple rods parallel to each other in one direction, The viewing angle conversion display device according to claim 12, wherein the lower electrode is configured in a pass-through electrode form that extends over the entire display area.

17. The viewing angle conversion display device according to claim 16, wherein the upper electrode is arranged in a direction parallel to the data line or gate line of the display device.

18. When no electric field is applied between the upper electrode and the lower electrode, the state of the liquid crystal layer remains constant throughout the entire viewing angle control layer. The viewing angle conversion display device according to claim 12, wherein when an electric field is applied between the upper electrode and the lower electrode, the state of the liquid crystal layer in the region where the upper electrode is located and the region where the upper electrode is not located are different from each other.

19. The second polarizing plate further includes a plurality of pixel lenses positioned on top of it, The field of view angle conversion display device according to any one of claims 12 to 18, wherein the lower surface of each pixel lens is flat and the upper surface is semicircular.

20. A vehicle comprising a display device according to any one of claims 1 or 12.

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