Stacked display device and image providing method thereof

Abstract

A stacked display device and an image providing method thereof are disclosed. The stacked display device according to the disclosure is characterized by including a first display panel having a first opening shape, and a second display panel stacked on the first display panel and having a second opening shape different from the first opening shape, wherein a ratio of a first maximum spatial frequency according to the first opening shape to a second maximum spatial frequency according to the second opening shape is outside a preset range.

Description

TECHNICAL FIELD

[0001] The disclosure relates to a stacked display apparatus and a method for providing an image thereof. More particularly, the disclosure relates to a stacked display apparatus including a plurality of display panels having different aperture shapes and a method for providing an image thereof.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application is based on and claims priority under 35 U.S.C. 119 to Korean Patent Application No. 10-2020-0105638, filed on August 21, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. BACKGROUND

[0004] Due to physical characteristics of each of the plurality of display panels in the stacked display apparatus, a moire phenomenon can occur. The moire phenomenon is a phenomenon in which water ripples are observed in the display apparatus, and due to light interference according to the wave property of light, interference fringes are generated by overlapping of two or more periodic water ripples.

[0005] When the plurality of display panels of the stacked display apparatus are the same, light passing through each of the display panels can have the same or similar wavelengths, and thus, interference of light can occur. In other words, when light having the same or similar wavelengths overlaps, constructive interference can occur when the phases of the two wavelengths are the same, and destructive interference can occur when the phases of the two wavelengths are opposite, resulting in the moire phenomenon.

[0006] Conventionally, in order to reduce the moire phenomenon, a method of disposing a diffusion film between the plurality of display panels of the stacked display apparatus has been used. However, when the diffusion film is disposed, due to the transmittance of the diffusion film, the intensity of light can be reduced, resulting in a blur phenomenon, which can cause degradation of image quality. SUMMARY

[0007] TECHNICAL PROBLEM

[0008] A stacked display apparatus is provided, which includes a plurality of display panels having different aperture shapes, the different aperture shapes representing arrangements or sizes of pixels of the display panels.

[0009] TECHNICAL SOLUTION

[0010] According to an embodiment, a stacked display apparatus is provided, the stacked display apparatus including: a first display panel in a form of a first aperture shape; and a second display panel in a form of a second aperture shape different from the first aperture shape, the second display panel being stacked on the first display panel, wherein a ratio of a first maximum spatial frequency of the first aperture shape to a second maximum spatial frequency of the second aperture shape is outside a predetermined range.

[0011] The stacked display device also includes a backlight unit, on which the first display panel is stacked.

[0012] The device further includes: a third display panel, which is in the form of a third opening and stacked on the second display panel, wherein the ratio of the third maximum spatial frequency to the first maximum spatial frequency is outside the predetermined range, and the ratio of the third maximum spatial frequency to the second maximum spatial frequency is outside the predetermined range.

[0013] The first maximum spatial frequency is obtained by analyzing the frequency components of first data about the shape of a first opening obtained by measuring the first optical profile of the first display panel, and the second maximum spatial frequency is obtained by analyzing the frequency components of second data about the shape of a second opening obtained by measuring the second optical profile of the second display panel.

[0014] Each of the first data regarding the shape of the first opening and the second data regarding the shape of the second opening includes multiple step functions.

[0015] The first image is configured to be provided via a first display panel, and the second image is configured to be provided via a second display panel. The first image and the second image are obtained by converting a light field (LF) image.

[0016] The diffusion film is not placed between the first display panel and the second display panel.

[0017] The first display panel is a structurally insulated panel (SIPS), and the second display panel is a planar to convertible panel (PLS).

[0018] The predetermined range is from 0.97 to 1.03.

[0019] The types of the first display panel and the second display panel are different from each other.

[0020] The resolutions of the first display panel and the second display panel are different from each other.

[0021] The methods by which the first display panel displays colors and the methods by which the second display panel displays colors are different from each other.

[0022] The aperture ratios of the first display panel and the second display panel are different from each other.

[0023] According to one embodiment, a method for providing an image of a stacked display device is provided, the method comprising: providing a first image through a first display panel in the form of a first opening shape; and providing a second image through a second display panel in the form of a second opening shape different from the first opening shape, the second display panels being stacked on the first display panel, wherein the ratio of a first maximum spatial frequency of the first opening shape to the second maximum spatial frequency of the second opening shape is outside a predetermined range.

[0024] The first and second images were obtained by converting the light field (LF) image.

[0025] According to various embodiments of this disclosure, moiré effects can be reduced by providing images via a stacked display device comprising multiple display panels having different opening shapes. Attached Figure Description

[0026] Figure 1 This is a view illustrating a stacked display device comprising two display panels according to one embodiment;

[0027] Figure 2a This is a front view of a stacked display device having three display panels according to one embodiment;

[0028] Figure 2b This is a cross-sectional view of a stacked display device having three display panels according to one embodiment;

[0029] Figure 3a This is a view showing the opening shape of a twisted nematic (TN) panel according to one embodiment;

[0030] Figure 3b This is a view showing the opening shape of an In-Plane-Switching (S-IPS) panel according to one embodiment;

[0031] Figure 3c This is a view showing the opening shape of a Plane to Line Switching (PLS) panel according to one embodiment;

[0032] Figure 3d This is a view showing the opening shape of a patterned vertical alignment (PVA) panel according to one embodiment;

[0033] Figure 3e This is a view showing the opening shape of a multi-domain vertical alignment (MVA) panel according to one embodiment;

[0034] Figure 3f This is a view showing the opening shape of an advanced multi-quadrant vertical alignment (AMVA) panel according to one embodiment;

[0035] Figure 3g This is a view showing the opening shape of a horizontal in-plane conversion (H-IPS) panel according to one embodiment;

[0036] Figure 4a This is a view showing the shape of the opening of a pixel in a TN panel according to one embodiment;

[0037] Figure 4b This illustrates the basis according to one embodiment. Figure 4a A view of the spatial frequency function of the opening shape;

[0038] Figure 4c This is a view showing the opening shape of pixels in a PLS panel according to one embodiment;

[0039] Figure 4d This illustrates the basis according to one embodiment. Figure 4c A view of the spatial frequency function of the opening shape;

[0040] Figure 5a This is a view showing the two-dimensional Fast Fourier Transform (FFT) spectrum of a TN panel according to one embodiment;

[0041] Figure 5b It is shown Figure 5a A graph showing the spatial frequency and spatial frequency intensity of a region of the spectrum.

[0042] Figure 5c This is a view showing the two-dimensional FFT spectrum of a PLS panel according to one embodiment;

[0043] Figure 5d It is shown Figure 5c A graph showing the frequency and frequency intensity of a region of the spectrum;

[0044] Figure 6 This is a view showing the aperture shape of a pixel in each of five display panels according to one embodiment, and a function of the spatial frequency of the aperture shape;

[0045] Figure 7 It is a graph of the moiré wavelength based on p according to one embodiment; and

[0046] Figure 8 This is a flowchart illustrating a method for providing an image via a stacked display device according to one embodiment. Detailed Implementation

[0047] A stacked display device according to one or more embodiments of the present disclosure can be implemented by stacking two or more display panels and presenting an image reflecting 3D depth by displaying an image on each of the two or more display panels. Specifically, the stacked display device can display different images on each of the multiple display panels to provide an image reflecting the visual depth caused by differences in physical displacement between the display panels. As an example, the stacked display device can render and display multiple light field (LF) images captured by a light field (LF) camera. Here, the stacked display device may be referred to as an LF display device.

[0048] Figure 1 This is a diagram illustrating a stacked display device 100 comprising two display panels according to one embodiment.

[0049] The stacked display device 100 may include multiple display panels. Figure 1 A stacked display device 100 comprising two display panels is shown according to one embodiment. (See also...) Figure 1 The stacked display device 100 may include a first display panel 110 and a second display panel 120. Furthermore, the second display panel 120 may be stacked on the first display panel 110.

[0050] As an example, the first display panel 110 and the second display panel 120 can be implemented as liquid crystal display (LCD) panels. When the first display panel 110 and the second display panel 120 are implemented as liquid crystal display (LCD) panels, the stacked display device 100 may further include a backlight unit. A backlight unit is a component for illuminating light onto the display panel. In other words, the backlight unit of the stacked display device 100 is a component for illuminating light onto the first display panel 110 and the second display panel 120. As an example, when the stacked display device 100 includes a backlight unit, the first display panel 110 may be stacked on top of the backlight unit.

[0051] The backlight unit may include a light guide plate, an optical sheet, and a light source, which may be implemented as a light-emitting diode (LED) or a cold cathode fluorescent lamp (CCFL). Furthermore, the backlight unit may be implemented as an edge-lit type (where the light source is positioned on the side of the light guide plate to indirectly illuminate the display panel) or as a direct-lit type (where the light source is positioned behind the display panel).

[0052] As another example, the first display panel 110 and the second display panel 120 can also be implemented as organic light-emitting diode (OLED) panels. When the first display panel 110 and the second display panel 120 are implemented as organic light-emitting diode (OLED) panels, the stacked display device 100 may not include a backlight unit. In other words, light can be emitted from each organic light-emitting diode (OLED) panel itself without a backlight unit.

[0053] Reference Figure 1 The first display panel 110 may have a first opening shape 110-1. The second display panel 120 may have a second opening shape 120-1 that is different from the first opening shape 110-1.

[0054] An aperture according to one or more embodiments of this disclosure can represent an area in which light is emitted from a pixel to the outside. Furthermore, the aperture shape according to one or more embodiments can represent the shape of the area (aperture) in which light is emitted to the outside of the display panel. The aperture shape can vary depending on the pixel arrangement and the size of a pixel. In other words, referring to… Figure 1 The first display panel 110 may include a first opening shape 110-1 according to the arrangement and size of the pixels of the first display panel 110, and the second display panel 120 may include a second opening shape 120-1 according to the arrangement and size of the pixels of the second display panel 120.

[0055] A pixel can refer to a unit used to display an image, and the display panel in the stacked display device 100 can display an image through multiple pixels. As an example, the display panel may include pixels representing a first color, pixels representing a second color, and pixels representing a third color, and colors can be represented by mixing the first, second, and third colors. Furthermore, the arrangement and size of pixels in the display can vary depending on the type, resolution, color representation method, and aperture ratio of the display panel. In other words, the aperture shape can be determined based on the type, resolution, color representation method, and aperture ratio of the display panel. Therefore, display panels with different types, resolutions, color representation methods, and / or aperture ratios can have different aperture shapes. Moreover, as the degree of difference between the aperture shapes of the display panels increases, the moiré effect in the stacked display device 100 can be reduced.

[0056] According to one embodiment, the degree of difference in the opening shape of each of the two display panels (e.g., the first display panel 110 and the second display panel 120) can be identified based on the maximum spatial frequency of the opening shape. Spatial frequency refers to the number of times the same structure is repeated per unit length when a structure of a certain shape and pattern is repeated according to position and arranged in space. Furthermore, the maximum value among the spatial frequencies of each opening shape can be defined as the maximum spatial frequency. Additionally, according to one or more embodiments, the spatial frequency can represent the arrangement of light emitted from the display panel to the outside through its openings (or areas).

[0057] Furthermore, when the two aperture shapes are different, the maximum spatial frequency of each aperture shape can be different. Specifically, as the degree of difference between the two aperture shapes increases, the difference between the maximum spatial frequencies of the two aperture shapes can also increase. Therefore, the degree of difference in the aperture shapes of each display panel can be identified based on the maximum spatial frequency of the aperture shapes.

[0058] For example, when the ratio (ρ) of the first maximum spatial frequency of the first opening shape to the second maximum spatial frequency of the second opening shape deviates more from a predetermined range (e.g., 0.97 to 1.03), it means that each opening shape of the first display panel 110 and the second display panel 120 is different to a greater extent.

[0059] As an example, the first maximum spatial frequency can be obtained by frequency domain analysis of data relating to the first opening shape of the first display panel, and the second maximum spatial frequency can be obtained by frequency domain analysis of data relating to the second opening shape of the second display panel.

[0060] Specifically, data about the shape of the opening in the display panel can be obtained by measuring the optical profile of the display panel. Optical profile measurement, according to one or more embodiments, can be a method of measuring the shape of the contrast appearing along a line in an image of a pixel emitting light in the display panel.

[0061] Data regarding the aperture shape represents spatial frequencies based on the arrangement shape of the display panel. As an example, data on the aperture shape obtained by measuring the optical profile can include function values ​​of a region along a cut line within the image-capturing pixels of the display panel. For example, the function value of a region along a cut line can be 0 or 1. For instance, the aperture shape data can include function values ​​where the function value in the region along the cut line that allows light to pass through is represented by 1, and the function value in the region that prevents light from passing through is represented by 0. In other words, when drawing data on the aperture shape along the cut line, a shape resulting from the superposition of multiple step functions can appear. That is, the data on the aperture shape can be data that includes the shape of step functions. The following will refer to... Figures 4a to 4dDescribes details about the aperture shape and light profile.

[0062] When data about the aperture shape of a display panel is obtained through optical profile measurements, frequency domain analysis of this data can yield the maximum spatial frequency based on the aperture shape. As an example, frequency component analysis can be performed using the Fast Fourier Transform (FFT) method. The Fast Fourier Transform is a mathematical technique that decomposes data into frequency components.

[0063] As an example, a Fast Fourier Transform (FFT) is performed on the data of the first opening shape to obtain a two-dimensional FFT spectrum. The spatial frequency domain of the first opening shape can be identified using the corresponding FFT spectrum. The maximum spatial frequency in the identified spatial frequency domain can be identified as the first maximum spatial frequency. The following will refer to... Figures 5a to 5d This describes a specific method for identifying the maximum spatial frequency using a two-dimensional FFT spectrum.

[0064] The second maximum spatial frequency can be obtained in the same way as the first maximum spatial frequency. That is, a fast Fourier transform of the data with the second aperture shape can be performed to obtain a two-dimensional FFT spectrum, and the maximum spatial frequency in the spatial frequency domain of the corresponding FFT spectrum can be identified as the second maximum spatial frequency.

[0065] Furthermore, when the ratio ρ of the first maximum spatial frequency of the first display panel 110 having a first opening shape to the second maximum spatial frequency of the second display panel 120 having a second opening shape is outside a predetermined range, the moiré effect of the stacked display device 100 can be reduced. As an example, the predetermined range can be from 0.97 to 1.03, and outside the predetermined range can mean less than 0.97 and / or greater than 1.03.

[0066] According to one embodiment, the ratio of the first maximum spatial frequency and the second maximum spatial frequency can be defined as ρ, which can be represented by Equation 1.

[0067] [Equation 1]

[0068]

[0069] In Equation 1, f1 can represent the first maximum spatial frequency value, and f2 can represent the second maximum spatial frequency value.

[0070] The reciprocal of f1 is λ1 and represents the wavelength relative to the maximum frequency corresponding to f1, and the reciprocal of f2 is λ2 and represents the wavelength relative to the maximum frequency corresponding to f2.

[0071] In one embodiment of this disclosure, moiré effects can be reduced when the ratio ρ of the first maximum spatial frequency and the second maximum spatial frequency is outside a predetermined range (i.e., 0.97 to 1.03). According to one embodiment, the first display panel 110 may be one of a planar-to-switching (PLS) panel and an advanced multi-quadrant vertical alignment (AMVA) panel, and the second display panel 120 may be a panel different from the first display panel 110, either a PLS panel or an AMVA panel, and the ratio ρ of the first maximum spatial frequency and the second maximum spatial frequency can be measured to be 1.03.

[0072] Furthermore, when the first display panel 110 is either a SIPS panel or a PLS panel and the second display panel 120 is a panel that is different from the first display panel 110 among the SIPS panel and PLS panels, the ratio ρ of the first maximum spatial frequency and the second maximum spatial frequency can be measured as 1.27.

[0073] As an example, the greater the deviation of the ρ value from the predetermined range (0.97 to 1.03), the greater the effect of reducing moiré patterns. In other words, the moiré reduction effect can be greater when the display panels are implemented with SIPS panels and PLS panels compared to when each stacked display panel is implemented with PLS panels and multi-quadrant vertical alignment (MVA) panels. The following will refer to... Figure 7 Describe the Mohr reduction effect based on the ρ value.

[0074] In one embodiment of this disclosure, a diffusion film may not be provided between the first display panel 110 and the second display panel 120 in the stacked display device 100. Conventionally, a diffusion film is provided between the display panels to reduce moiré effects occurring in stacked displays. However, when a diffusion film is provided, the light intensity decreases due to the transmittance of the diffusion film, resulting in blurring and image quality degradation. Therefore, since the stacked display 100 according to this disclosure includes a first display panel 110 and a second display panel 120 with different opening shapes, moiré effects can be reduced without providing a diffusion film.

[0075] exist Figure 1In the present disclosure, the stacked display device 100 is shown as including two display panels 110 and 120, but is not limited thereto. In other words, the stacked display device 100 according to the present disclosure may include three or more display panels. As an example, when the stacked display device 100 includes three display panels, the stacked display device 100 may also include a third display panel stacked on the second display panel 120. Furthermore, the third display panel may have a third opening shape and may have a third maximum spatial frequency according to the third opening shape. In addition, the ratio of the third maximum spatial frequency to the first maximum spatial frequency and the ratio of the third maximum spatial frequency to the second maximum spatial frequency may be outside a predetermined range (e.g., 0.97 to 1.03).

[0076] Figure 2a This is a front view of a stacked display device having three display panels according to an embodiment of the present disclosure. Figure 2b This is a cross-sectional view of a stacked display device having three display panels according to an embodiment of the present disclosure.

[0077] Figure 2a and Figure 2b The stacked display device 200 may include three LCD display panels 210, 220, and 230 and a backlight 240. Furthermore, the first display panel 210 and the third display panel 230 may have a first opening shape, and the second display panel 220 may have a second opening shape.

[0078] As an example, the first display panel 210 and the third display panel 230 can be the same type of panel, while the second display panel 220 can be of a different type than the first display panel 210 and the third display panel 230.

[0079] The type of panel disclosed herein can be identified by at least one of the following: the arrangement of pixel electrodes, common electrodes, and liquid crystal layers in the display panel; the dielectric anisotropy of the liquid crystal; and the initial alignment direction of the liquid crystal. As an example, an LCD display panel may include a twisted nematic (TN) panel, a vertical alignment (VA) panel, a multi-quadrant vertical alignment (MVA) panel, an in-plane conversion (IPS) panel, a surface-to-line conversion (PLS) panel, an edge field conversion (FFS) panel, etc. For example, Figure 2a and Figure 2b The first display panel 210 and the third display panel 230 of the stacked display device 200 may be twisted nematic (TN) panels, and the second display panel 220 may be a super IPS (S-IPS) panel.

[0080] Figure 2bThe illustration shows a case where the type of the second display panel 220 of the stacked display device 200 differs from that of the first display panel 210 and the third display panel 230. However, stacked display devices according to one or more embodiments may include not only cases where the types of display panels are different, but also various embodiments where the opening shapes of the display panels are different.

[0081] In other words, in another embodiment, the first display panel 210 and the third display panel 230 may have the same resolution, while the resolution of the second display panel 220 may be different from that of the first display panel 210 and the third display panel 230. For example, the first display panel 210, the second display panel 220, and the third display panel 230 may all be TN panels, and the first display panel 210 and the third display panel 230 may have FHD resolution, while the second display panel 220 may be a TN panel with UHD resolution.

[0082] In another embodiment, the first display panel 210 and the third display panel 230 may be panels composed of pixels having three colors: red, green, and blue (RGB), while the second display panel 220 may be a panel composed of pixels having only one single color among RGB. That is, the second display panel 220 may have a different method of displaying colors than the first display panel 210 and the third display panel 230.

[0083] In other words, the first display panel 210 and the third display panel 230 can be display panels with a first opening shape, and the second display panel 220 can be a display panel with a second opening shape. The opening shape of the display panel can be identified by the type, resolution, color representation method and aperture ratio of each display panel.

[0084] Furthermore, as described above, the opening shapes of the first display panel 210 and the third display panel 230 can be a first opening shape, and the opening shape of the second display panel 220 can be a second opening shape, but are not limited thereto. The opening shapes of the first display panel 210, the second display panel 220, and the third display panel 230 can be different from each other. Additionally, the first display panel 210 and the second display panel 220 can have a first opening shape, and the third display panel 230 can have a second opening shape. Optionally, the second display panel 220 and the third display panel 230 can have a first opening shape, and the first display panel 210 can have a second opening shape.

[0085] Figure 3a This is a view showing the opening shape of a twisted nematic (TN) panel according to one embodiment. Figure 3bThis is a view showing the opening shape of an S-IPS (Super-IPS) panel according to one embodiment. Figure 3c This is a view showing the opening shape of a PLS panel according to one embodiment. Figure 3d This is a view showing the opening shape of a PVA panel according to one embodiment. Figure 3e This is a view showing the opening shape of an MVA panel according to one embodiment. Figure 3f This is a view showing the opening shape of an AMVA panel according to one embodiment. Figure 3g This is a view showing the shape of the opening of an H-IPS panel according to one embodiment.

[0086] like Figures 3a to 3g As shown, the opening shape of each display panel can be different depending on the type of display panel. As an example, the opening shape of each display panel can be identified by the image-capturing pixels that emit light in each display panel.

[0087] Furthermore, when using two display panels with different degrees of opening shape, the moiré reduction effect of the stacked display device 100 can be significant.

[0088] For example, Figure 3a A pixel in a TN panel has a trapezoidal shape, allowing light to be emitted from all areas within that pixel to the outside. Furthermore, Figure 3b A pixel in an S-IPS panel has a hooded shape and can include an area where light is not emitted to the outside.

[0089] Assuming in Figures 3a to 3g In the panel, Figure 3b The aperture shape of the S-IPS panel and Figure 3c The difference between the opening shapes of the PLS panels is the greatest, so the moiré reduction effect can be maximized when the first display panel is a PLS panel and the second display panel is an S-IPS panel.

[0090] Furthermore, assuming in Figures 3a to 3g In the panel, Figure 3a The opening shape of the TN panel and Figure 3c If the difference between the opening shapes of the PLS panels is minimal, then when the first display panel is a TN panel and the second display panel is a PLS panel, the moiré reduction effect can be relatively small.

[0091] In the following text, reference will be made to Figures 4a to 6 Describe the methods for measuring the shape of openings of different degrees.

[0092] Figure 4a This is a view showing the shape of the opening of a pixel in a TN panel according to one embodiment.Figure 4b It shows the basis Figure 4a A view of the spatial frequency function of the opening shape.

[0093] Figure 4c This is a view showing the opening shape of pixels in a PLS panel according to one embodiment. Figure 4d It shows the basis Figure 4c A view of the spatial frequency function of the opening shape.

[0094] Figure 4a An image of a pixel emitting light in a TN panel is shown by measuring the optical profile of a pixel in the TN panel.

[0095] Furthermore, first data regarding the shape of the first opening of a pixel in the TN panel can be obtained by measuring the optical profile of the TN panel. In other words, the first data represents the shape of the first opening of a pixel in the TN panel. Figure 4a The data shows the light and dark shapes of a pixel in the TN panel that emits light along a line 40-1.

[0096] like Figure 4b As shown, the first data includes function values ​​of an image of one pixel emitting light captured in the TN panel, relative to a region along a line 40-1. These function values ​​can be 0 or 1. In other words, the first data can include the following function values ​​during the capture... Figure 4a In the region of a line 40-1 in an image of a pixel in the TN panel, the function value of the region that allows light to pass through is 1, and the function value of the region that prevents light from passing through is 0. When drawn along a line 40-1, it can take the form of a step function consisting of three parts.

[0097] Figure 4c It is an image of a pixel emitting light in a PLS panel by measuring the optical profile of that pixel.

[0098] Second data regarding the shape of the second opening of a pixel in the PLS panel can be obtained by measuring the optical profile of the PLS panel. In other words, the second data represents the shape of the second opening of the pixel in the PLS panel. Figure 4c The data of the light and dark shapes appearing along a line 40-2 in the image of a pixel emitting light in the PLS panel.

[0099] like Figure 4d As shown, the second data includes a function value of an image of one pixel emitting light in the PLS panel relative to a region along a line 40-2, where the function value can be 0 or 1. In other words, the second data can include the following function values ​​during the capture... Figure 4cIn the region of a line 40-2 in the image of a pixel in the PLS panel, the function value of the region that allows light to pass through is 1, and the function value of the region that prevents light from passing through is 0. When drawn along a line 40-2, it can take the form of a step function consisting of three parts.

[0100] Specifically, Figure 4b The first data and Figure 4d The second data in the diagram is a function drawn along lines 40-1 and 40-2 on the X-axis, and can be a step function consisting of three parts. Furthermore, since... Figure 4a One of the lines 40-1 and Figure 4c The opening shapes of a line 40-2 in the equation are similar, so the first and second data can have similar function shapes.

[0101] Figure 5a This is a view showing the two-dimensional Fast Fourier Transform (FFT) spectrum of a TN panel according to one embodiment. Figure 5b It is shown Figure 5a A graph showing the spatial frequency and spatial frequency intensity of a region of the spectrum.

[0102] Specifically, Figure 5a The two-dimensional spectrum is obtained by means of, such as Figure 3a The Fast Fourier Transform (FFT) of the brightness and darkness along a line in an image taken from the opening shape of the TN panel shown is represented in the spatial frequency domain. Figure 5a The x-axis and y-axis components of the spectrum are frequency components and can be measured in Hertz (Hz). Furthermore, when a region in the spectrum appears darker, it likely means that its intensity is greater relative to the corresponding spatial frequency. In other words, from... Figure 5a The 2D spectrum shows that, as Figure 3a The aperture shape of the TN panel shown has a maximum intensity at a spatial frequency of 256 Hz.

[0103] Figure 5b Is Figure 5a A graph showing the intensity of each spatial frequency in the intensity concentration portion of the 2D FFT spectrum. Figure 5b The x-axis of the graph represents the frequency components, and the y-axis components are obtained by normalizing the ratio of the intensity relative to each spatial frequency to a range of 0 to 1. (See reference...) Figure 5b ,like Figure 3a The shape of the opening in the TN panel shown can be measured to have a maximum spatial frequency of 512 Hz.

[0104] Figure 5c This is a view showing the two-dimensional FFT spectrum of a PLS panel according to an embodiment of the present disclosure.Figure 5d It is shown Figure 5c A graph showing the frequency and frequency intensity of a region of the spectrum.

[0105] Specifically, Figure 5c The two-dimensional spectrum is obtained by means of, such as Figure 3c The Fast Fourier Transform (FFT) of the contrast pattern along a line in an image taken from the aperture shape of the PLS panel shown is represented in the spatial frequency domain as a spectrum. Figure 5c As can be seen from the two-dimensional spectrum, such as Figure 3c The opening shape of the PLS panel shown has a maximum intensity at a spatial frequency of 256 Hz.

[0106] also, Figure 5d Is Figure 5c A graph showing the intensity of each spatial frequency in the intensity concentration region of the two-dimensional FFT spectrum. Figure 5d The x-axis of the graph represents the frequency components, and the y-axis components are obtained by normalizing the ratio of intensity to each spatial frequency to a range of 0 to 1. (See reference...) Figure 5d ,like Figure 3c The shape of the opening in the PLS panel shown can be measured to have a maximum spatial frequency of 492 Hz.

[0107] Therefore, by measuring the optical profiles of each of the TN and PLS panels, the ratio ρ of the maximum spatial frequency (512 Hz) based on the aperture shape of the TN panel to the maximum spatial frequency (492 Hz) based on the aperture shape of the PLS panel can be measured as 1.04.

[0108] Through Figures 4a to 5d The aforementioned optical profile measurement can measure the maximum spatial frequency for each display panel based on the aperture shape. Furthermore, the ratio ρ between the maximum spatial frequencies of two display panels can be calculated using the corresponding measurements.

[0109] Figure 6 This is a view showing the aperture shape of a pixel in each of five display panels according to one embodiment, and the shape as a function of the spatial frequency of the aperture shape.

[0110] By measuring the optical profile of a pixel in a Super IPS (S-IPS) panel, Figure 6Image 630 shows an image of a pixel emitting light in an S-IPS panel. Furthermore, curve 630-1 is shown as a function of spatial frequency, representing the contrast along a line 60 of image 630. In other words, curve 630-1 is a curve within the region of a line 60 in image 630 where the area allowing light to pass through is high (e.g., 1) and the area preventing light from passing through is low (e.g., 0).

[0111] Image 640 represents an image of a pixel emitting light in a PVA panel, obtained by measuring the optical profile of a pixel in the image vertical alignment (PVA) panel. Furthermore, curve 640-1 is shown as a function of spatial frequency, representing the contrast along a line 60 of image 640. In other words, curve 640-1 is a curve within the region of a line 60 in image 640 where the area allowing light to pass through is high (e.g., 1) and the area preventing light from passing through is low (e.g., 0).

[0112] Image 650 represents an image of a pixel emitting light in an MVA panel by measuring the optical profile of a pixel in the panel. Furthermore, curve 650-1 is a curve showing the contrast along a line 60 of image 650 as a function of spatial frequency. In other words, curve 650-1 is a curve within the region of a line 60 in image 650 where areas allowing light to pass through are high (e.g., 1) and areas preventing light from passing through are low (e.g., 0).

[0113] Image 660 represents an image of a pixel emitting light in an Advanced Multi-Quadrant Vertical Alignment (AMVA) panel by measuring the optical profile of a pixel in the panel. Furthermore, curve 660-1 is a curve showing the contrast along a line 60 of image 660 as a function of spatial frequency. In other words, curve 660-1 is a curve within the region of a line 60 in image 660 where areas allowing light to pass through are high (e.g., 1) and areas preventing light from passing through are low (e.g., 0).

[0114] Image 670 represents an image of a pixel emitting light in an AMVA panel by measuring the optical profile of a pixel in a horizontally in-plane conversion (H-IPS) panel. Furthermore, curve 670-1 is shown as a function of spatial frequency, representing the contrast along a line 60 of image 670. In other words, curve 670-1 is a curve within the region of a line 60 in image 670 where the area allowing light to pass through is high (e.g., 1) and the area preventing light from passing through is low (e.g., 0).

[0115] In addition, as mentioned above Figures 5a to 5dThe above can be described as being relative to Figure 6 The Fast Fourier Transform (FFT) of curves 630-1 to 670-1 measures the maximum spatial frequency of each corresponding display panel. As an example, the ratio ρ of the maximum spatial frequency between two display panels can be measured according to two different display panel types, as shown in Table 1 below.

[0116] Table 1

[0117]

[0118]

[0119] Referring to Table 1, the ratio of the maximum spatial frequency based on the aperture shape of the SIPS panel to the maximum spatial frequency based on the aperture shape of the PLS panel is 1.27 or 0.787, which is the maximum difference from a predetermined range (e.g., 0.97 to 1.03). For example, when the first display panel is a SIPS panel and the second display panel is a PLS panel, the ratio of the maximum spatial frequencies can be measured as 1.27. Furthermore, when the first display panel is a PLS panel and the second display panel is a SIPS panel, the ratio of the maximum spatial frequencies can be measured as 0.787. In other words, when the stacked display device 100 is implemented using multiple display panels including SIPS and PLS panels, the moiré reduction effect can be relatively large.

[0120] In other words, the stacked display device 100 can provide images with reduced moiré effects because the stacked display device 100 is implemented using multiple display panels, each of which has a maximum frequency ratio of 1.03 or greater or 0.97 or less for each display panel.

[0121] Figure 7 It is a graph of moiré wavelength based on ratio ρ according to one embodiment.

[0122] Figure 7 The moiré wavelength λ is shown as the ratio ρ of the first maximum spatial frequency of the first aperture shape to the second maximum spatial frequency of the second aperture shape. m The graph shows the curves. As provided in the example above, the stacked display device 100 may include a first display panel having a first opening shape and a second display panel having a second opening shape.

[0123] Moiré wavelength λ m The wavelength of the moiré pattern produced by the moiré phenomenon is λ, which could mean the moiré wavelength λ. m The larger the wavelength λ, the more pronounced the Moiré effect becomes. In other words, the Moiré wavelength λ... m The larger the image size, the more likely the image output by the stacked display device 100 is to be affected by the Moiré effect.

[0124] As an example, when the first opening shape and the second opening shape are the same, the ratio ρ of the first maximum spatial frequency and the second maximum spatial frequency according to the second opening shape can be 1.

[0125] Reference Figure 7 As can be seen, the moiré wavelength decreases when the ρ between the two display panels is greater than or less than 1. Furthermore, when ρ is outside a predetermined range (a), that is, when ρ is greater than or equal to 1.03 or less than or equal to 0.97, there is an effect of reducing the moiré effect.

[0126] Figure 8 This is a flowchart illustrating a method for providing an image via a stacked display device according to one embodiment.

[0127] The stacked display device 100 may include a first display panel having a first opening shape and a second display panel having a second opening shape. Furthermore, the second display panel may be stacked on top of the first display panel.

[0128] Furthermore, the stacked display device 100 can provide a first image via a first display panel in the form of a first opening shape (S810). Additionally, the stacked display device 100 can provide a second image via a second display panel in the form of a second opening shape different from the first opening shape, wherein the second display panel is configured to be stacked on top of the first display panel (S820). As an example, the first image and the second image can be images obtained by converting a light field (LF) image. Furthermore, the first image and the second image can be moving images. An LF image is a collection of multiple images captured by a light field (LF) camera and can include multiple images of an object captured from different perspectives. Furthermore, the LF image can be converted into a first image and a second image, and provided to the first display panel and the second display panel of the stacked display device 100, respectively. For example, the first image and the second image can be obtained by performing factorization on the LF image. Factorization is a technique used to convert an LF image into an image provided to each of the multiple display panels of the stacked display device. Although... Figure 8 It is shown that a first image is provided through a first display panel and then a second image is provided through a second display panel, but one or more embodiments are not limited thereto, and operations S810 and S820 can be performed simultaneously.

[0129] To fully understand the configuration and effects of this disclosure, embodiments of this disclosure have been described with reference to the accompanying drawings. However, this disclosure is not limited to the embodiments disclosed herein and can be implemented in various forms with various modifications. The description of embodiments is provided to illustrate the inventive concept of this disclosure and to inform those skilled in the art of the scope of this disclosure. In the drawings, for ease of description, the dimensions of the components are enlarged and shown, and the scale of each component may be enlarged or reduced.

[0130] In this disclosure, the terms "comprising" and "including" indicate the presence of a feature, number, step, operation, component, element or combination thereof described in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, elements or combinations thereof.

[0131] In the specification, the terms “A or B”, “at least one of A and / or B”, or “one or more of A and / or B” can include all possible combinations of the items listed together. For example, the terms “A or B” or “at least one of A and / or B” can mean (1) at least one A, (2) at least one B, or (3) both at least one A and at least one B.

[0132] In this specification, the terms "first," "second," etc., are used to describe various elements regardless of their order and / or importance and to distinguish one element from others, but are not limited to the corresponding elements. For example, "first user equipment" and "second user equipment" can refer to different user equipment regardless of their order or importance. For example, without departing from the scope as described herein, a first element can be referred to as a second element, or similarly, a second element can be referred to as a first element.

[0133] When one element (e.g., a first element) is "operably or communicatively coupled" or "connected" to another element (e.g., a second element), the element may be directly coupled to the other element, or may be coupled through the other element (e.g., a third element). On the other hand, when one element (e.g., a first element) is "directly coupled / connected" or "directly connected" to another element (e.g., a second element), the element (e.g., a third element) may not exist between the other elements.

[0134] In the specification, the term "configured as" may be changed in certain circumstances to, for example, "suitable for," "capable of," "designed for," "suitable for," "made as," or "capable of." The term "configured as (set as)" does not necessarily mean "specifically designed for" at the hardware level. In some cases, the term "device configured as" may mean "the device is able" to do something together with another device or component. For example, the phrase "processor configured (set as) to perform A, B, and C" may refer to a general-purpose processor (e.g., CPU or application processor) capable of performing the corresponding operations by executing a dedicated processor (e.g., an embedded processor) for performing the corresponding operations or by executing one or more software programs stored in a storage device.

[0135] When a component is described as being "on" another component or "in contact with" another component, it is understood that it may be in direct contact with or directly connected to the other component, but there may be other components in between. Conversely, when a component is described as being "directly on" another component or "directly in contact with" another component, it is understood that there may be no other components in between. Other expressions describing relationships between components (i.e., "between," "directly between," etc.) should be interpreted similarly.

[0136] Terms such as "first" and "second" may be used to describe various components, but these components should not be limited by these terms. These terms are used only to distinguish one component from others. For example, a "first" component may be named a "second" component without departing from the scope of this disclosure, and vice versa.

[0137] The singular form may include the plural form unless the context clearly indicates otherwise. Expressions such as “comprising” or “having” as used herein are intended to indicate the presence of features, numbers, steps, operations, elements, parts or combinations thereof as specified in the specification, and should not be construed as excluding the possible presence or addition of one or more other features, numbers, steps, operations, elements, parts or combinations thereof.

[0138] Unless otherwise indicated, the terminology used in the embodiments of this disclosure may be interpreted in the meanings known to those skilled in the art.

[0139] Each of the aforementioned components of the electronic device according to various embodiments of the present disclosure may be configured by one or more components, and the names of the corresponding components may vary depending on the type of electronic device. The electronic device according to various embodiments of the present disclosure may be configured to include at least one of the aforementioned components, and some components may be omitted or additional components may be included. Furthermore, the description of exemplary embodiments of the present disclosure is intended to be illustrative and not to limit the scope of the claims, and many substitutions, modifications, and variations will be apparent to those skilled in the art.

[0140] Although this disclosure has been shown and described with reference to various embodiments thereof, those skilled in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of this disclosure as defined by the appended claims and their equivalents.

Claims

1. A stacked display device, comprising: The first display panel is in the form of a first opening. as well as The second display panel has a different opening shape than the first opening, and the second display panel is stacked on top of the first display panel. Wherein the ratio of the first maximum spatial frequency of the first opening shape to the second maximum spatial frequency of the second opening shape is outside a predetermined range, The first maximum spatial frequency is obtained by analyzing the frequency components of first data relating to the first opening shape obtained by measuring the first optical profile of the first display panel using a fast Fourier transform method. The second maximum spatial frequency is obtained by analyzing the frequency components of second data relating to the second aperture shape obtained by measuring the second optical profile of the second display panel using a fast Fourier transform method. The predetermined range is from 0.97 to 1.

03.

2. The apparatus according to claim 1, further comprising: Backlight unit, The first display panel is stacked on the backlight unit.

3. The apparatus according to claim 1, further comprising: The third display panel, in the form of a third opening, is stacked on top of the second display panel. The ratio of the third maximum spatial frequency to the first maximum spatial frequency of the third opening shape is outside the predetermined range, and The ratio of the third maximum spatial frequency to the second maximum spatial frequency is outside the predetermined range.

4. The apparatus according to claim 3, Each of the first data relating to the first opening shape and the second data relating to the second opening shape includes multiple step functions.

5. The apparatus according to claim 1, The first image is configured to be provided via the first display panel, the second image is configured to be provided via the second display panel, and The first and second images were obtained by converting light field (LF) images.

6. The apparatus according to claim 1, The diffusion film is not disposed between the first display panel and the second display panel.

7. The apparatus according to claim 1, The first display panel is a structurally insulated panel (SIPS), and the second display panel is a planar-to-converter (PLS) panel.

8. The apparatus according to claim 1, The types of the first display panel and the second display panel are different from each other.

9. The apparatus according to claim 1, The resolutions of the first display panel and the second display panel are different from each other.

10. The apparatus according to claim 1, The methods for displaying colors using the first display panel and the methods for displaying colors using the second display panel are different from each other.

11. The apparatus according to claim 1, The aperture ratios of the first display panel and the second display panel are different from each other.

12. A method of providing an image for a stacked display device, comprising: A first image is provided through a first display panel in the form of a first opening shape; as well as A second image is provided by a second display panel having a second opening shape different from the first opening shape, the second display panel being stacked on top of the first display panel. Wherein the ratio of the first maximum spatial frequency of the first opening shape to the second maximum spatial frequency of the second opening shape is outside a predetermined range, The first maximum spatial frequency is obtained by analyzing the frequency components of first data relating to the first opening shape obtained by measuring the first optical profile of the first display panel using a fast Fourier transform method. The second maximum spatial frequency is obtained by analyzing the frequency components of second data relating to the second aperture shape obtained by measuring the second optical profile of the second display panel using a fast Fourier transform method. The predetermined range is from 0.97 to 1.

03.

13. The method according to claim 12, The first and second images were obtained by converting light field (LF) images.

Images