Patent Description:
When two patterns that repeat at desired intervals overlap, a pattern having a new repetition interval may be generated due to interference between the patterns. Such the pattern is referred to as moiré. In general, a 3D display may be manufactured by displacing a lens on a display panel. The moiré may occur due to pixels uniformly provided on the display panel and lens uniformly provided thereon. The moiré may cause a degradation in quality of a 3D image. In particular, a striped pattern by moiré occurring when the display panel is applied to a 3D HUD may interrupt driving.

<CIT> refers to a color display device. The color display device comprises an array of subpixels of at least four different colors including at least two relatively higher luminous color subpixels and at least two relatively lower luminous color subpixels. The subpixels are arranged into groups forming at least two distinct types of pixels. Each pixel type includes the two relatively higher luminous color subpixels and at least one of the two relatively lower luminous color subpixels. The pixel types are arranged in a pattern such that the relative locations of the two relatively higher luminous color subpixels in each pixel is repeated in adjacent pixels, and the relative location of at least one of the two relatively lower luminance color subpixels is not repeated in at least one adjacent pixel.

<CIT> refers to a stereoscopic image display apparatus capable of reducing a luminance deviation between viewing areas and allowing a high-quality 3D image to be viewed without glasses. The stereoscopic image display apparatus includes one view matrix composed of M subpixels arranged in the first direction and N subpixels arranged in the second direction. Some of the subpixels constituting the one view matrix are opened by the aperture, and the remaining subpixels are covered by the black matrix. And the number of subpixels opened by the opening in the viewing area formed by the lenticular lens is N pieces.

<CIT> refers to a stereoscopic display device and a method for manufacturing the same. The stereoscopic display device comprises a display panel and a grating, wherein the display panel comprises a plurality of first display units and a plurality of second display units. The plurality of first display units and the plurality of second display units are arranged alternately in a Y direction of the display panel. The grating comprises a plurality of optical structures arranged parallel to each other. A preset angle β is arranged between the optical structure and an X direction of the display panel, thereby reducing Moire fringe phenomenon during displaying.

The publication of<NPL>, refers to a flat panel display having a slanted subpixel arrangement suitable for a multi-view display. A set of <NUM> × N subpixels (M × N subpixels for each R, G, and B color) is combined with one of the cylindrical lenses constituting a lenticular sheet to construct a three-dimensional pixel. Subpixels with the same color in each three-dimensional pixel have different horizontal positions, and these R, G, and B subpixels are repeated in the horizontal direction. In addition, ray-emitting areas of the subpixels in a three-dimensional pixel are continuous in the horizontal direction for each color. One vertical edge of one subpixel has the same horizontal position as the opposite vertical edge of one of the other subpixels of the same color subpixels.

<CIT> discloses a conductive film, display device having the same, and method of evaluating conductive film. In the conductive film, a display unit is formed by using sub-pixels that have different forms for two colors, cycles of sub-pixel array patterns of respective colors are different, or a barycenter of a single sub-pixel within a single pixel is at a position different from that of a straight line connecting barycenters of the other sub-pixels.

<CIT> discloses a spacer arrangement for flat panel display. An arrangement of spacer posts in a flat panel display is used to maintain a fixed separation between a back plate and a face plate. The spacer can be attached to the face plate at each combined phosphor-free area without disrupting the uniformity of the distribution of phosphors on the face plate.

It is the object of the present invention to provide an improved display panel. This object is solved by the subject matter of independent claim <NUM>.

The shape of each of the plurality of pixels may be determined based on a pattern by a combination of a plurality of subpixels included in each of the plurality of pixels, and each of the plurality of pixels may have a same pattern in the display panel.

The repetition interval of the pattern may include at least one of a first interval at which the pattern is repeated in a horizontal direction, a second interval at which the pattern is repeated in a vertical direction, and a third interval at which the pattern is repeated in a direction corresponding to a combination of the horizontal direction and the vertical direction.

The plurality of pixels may include liquid crystals.

According to another aspect of an example embodiment, there is provided a third-dimensional (3D) display device including a display panel including a plurality of pixels and a plurality of placement spaces provided between the plurality of pixels, and an optical layer configured to control a direction of light incident from the display panel, wherein the plurality of pixels are uniformly provided in the display panel based on a pattern corresponding to the plurality of placement spaces, and wherein a frequency corresponding to a repetition interval of the pattern is outside of a cognitive frequency band that is visible to a user.

The shape of each of the plurality of pixels may be determined based on a pattern by a combination of a plurality of subpixels included in each of the plurality of pixels, and each of the plurality of pixels has a same pattern in the display panel.

A structure of subpixels included in each of the plurality of pixels may be determined based on each of the plurality of placement spaces that may include a spacer.

According to another aspect of an example embodiment, there is provided a three-dimensional (3D) head-up display (HUD) device including a display panel including a plurality of pixels and a plurality of a placement spaces provided between the plurality of pixels, and an optical layer included in a windshield of a vehicle and configured to control a direction of light incident from the display panel, and at least one processor configured to generate a panel image that is displayed on the display panel based on positions of both eyes of a user to provide a 3D image to the user through the optical layer, wherein the plurality of pixels are uniformly provided in the display panel based on a pattern corresponding to the plurality of placement spaces, and a frequency corresponding to a repetition interval of the pattern is outside of a cognitive frequency band that is visible to the user.

The pattern may include at least one pixel, and wherein a structure of subpixels included in the at least one pixel may be determined based on each of a plurality of placement spaces in the display panel.

A structure of subpixels included in each of the plurality of pixels may be determined based on each of the plurality of placement spaces that include a spacer.

According to an aspect of an example embodiment, there is provided a display panel including a plurality of pixels, a plurality of subpixels included in each of the plurality of pixels, a plurality placement spaces provided between the plurality of pixels, wherein the plurality of pixels are uniformly provided in the display panel based on a pattern of the plurality of subpixels corresponding to the plurality of placement spaces, and wherein a frequency corresponding to a repetition interval of the pattern is outside of a cognitive frequency band that is visible to a user.

The above and/or other aspects will be more apparent by describing example embodiments with reference to the accompanying drawings, in which:.

Reference will now be made in detail to example embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. Example embodiments are described below in order to explain the disclosure by referring to the figures.

The following structural or functional descriptions are example to describe the example embodiments, and the scope of the example embodiments is not limited to the descriptions provided in the present specification. Various changes and modifications can be made thereto by those of ordinary skill in the art.

Although terms of "first" or "second" are used to explain various components, the components arc not limited to the terms. These terms may be used only to distinguish one component from another component. For example, a "first" component may be referred to as a "second" component, or similarly, and the "second" component may be referred to as the "first" component within the scope of the right according to the concept of the disclosure.

As used herein, the singular forms are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components or a combination thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

Unless otherwise defined herein, all terms used herein including technical or scientific terms have the same meanings as those generally understood by one of ordinary skill in the art. Terms defined in dictionaries generally used may be construed to have meanings matching with contextual meanings in the related art and are not to be construed as an ideal or excessively formal meaning unless otherwise defined herein.

The following example embodiments may be applied to recognize a user, to display a line in an augmented reality (AR) system, such as a smart vehicle, or to generate visual information for assisting steering of an autonomous driving vehicle. Also, the example embodiments may be applied to track visual information and assist safe and pleasant driving in a device that includes a smart system, such as a head-up display (HUD) installed for driving assistance or complete autonomous driving of a vehicle. The example embodiments may be applied to, for example, a smartphone, a mobile device, a navigation device, an autonomous driving vehicle, and a smart vehicle.

<FIG> illustrate examples of moiré occurring on a display panel in a pixel structure of a general dual domain display. In detail, <FIG> illustrates an example of a pixel structure of a dual domain display, <FIG> illustrates an example of a frequency image in the pixel structure of <FIG> illustrates an example of moiré occurring in response to manufacturing a 3D display in the pixel structure of <FIG>.

Referring to <FIG>, the 3D display device may be manufactured by overlapping lenses on a display panel that includes pixels. Here, interference may occur due to the pixels and the lenses that are uniformly placed on the display panel. That is, interference may occur due to the lenses that are uniformly placed on a single display panel on which the pixels are uniformly placed. When a frequency of moiré occurring due to the interference is in a low frequency domain, a user may recognize the moiré as a stripe. In general, eyes of a human may not recognize a pattern with a frequency of greater than or equal to <NUM> cycle/degree and may recognize a pattern with a frequency of less than <NUM> cycle/degree. The frequency of less than <NUM> cycle/degree may correspond to a cognitive frequency band or a visibility circle. Referring to <FIG>, a portion indicated with a circle with a solid line represents a boundary of a frequency of <NUM> cycle/degree and may be referred to as a cognitive frequency boundary. Here, a frequency included in the cognitive frequency boundary, that is, the frequency of less than <NUM> cycle/degree may be a cognitive frequency of a moiré frequency. For a periodic interference pattern occurring due to moiré in a moiré frequency may be recognized at eyes of the user as moiré as shown in <FIG>. Moiré is a factor that degrades quality of a 3D image and needs to be reduced or removed.

In general, a cause for moiré may be more easily analyzed in a frequency domain rather than in a space domain. Therefore, presence or absence of moiré may be verified from an image transformed to the frequency domain. Also, although moiré generally defines a periodic pattern that is newly generated regardless of whether it is visible to eyes of the user, a periodic pattern that is viewed by eyes of the user may be moiré for clarity of description. The term periodic pattern may be a pattern that is repeated at a desired interval.

In the dual domain display of <FIG>, odd rows of pixels are tilted to the left and even rows of pixels are tilted to the right. A pixel structure in which a pattern of pixels of odd rows and a pattern of pixels of even rows are different may be a dual domain structure. In the dual domain structure, a pixel pattern repetition interval increases due to a difference between shapes of upper pixels and lower pixels compared to a single domain structure, and as a frequency is inversely proportional to the pattern repetition interval, a frequency may decrease and be generated in a low frequency domain accordingly. The overlap between a low frequency and a lenticular lens may increase a moiré occurrence probability.

In one example, it is possible to remove moiré from the cognitive frequency band by changing a period of moiré through a modification in the pixel structure to decrease the pixel pattern repetition interval. For example, the dual domain structure may be used to enhance a viewing angle of a display. However, a device having a relatively small viewing angle compared to a general display, such as a head-up display (HUD) device, the dual domain structure for enhancing the viewing angle may not be required. Accordingly, moiré may be removed from the cognitive frequency band by changing a pixel structure of a dual domain with a pixel structure of a single domain and thereby changing a period of moiré.

<FIG> illustrates examples of a pixel structure of a single domain display panel and a frequency image corresponding to the pixel structure according to an example embodiment. <FIG> illustrates an example of a 3D display device <NUM> configured to output light of pixels <NUM> in a specific direction by placing an optical layer <NUM> on a display panel <NUM>. <FIG> illustrates an example of a frequency domain image when the optical layer <NUM> is attached on the display panel <NUM>.

For example, the display panel <NUM> may be a single domain display panel on which even rows of pixels and odd rows of pixels are in the same pattern. Each of the pixels <NUM> may include a plurality of subpixels, for example, a red (R) subpixel <NUM>-<NUM>, a green (G) subpixel <NUM>-<NUM>, and a blue (B) subpixel <NUM>-<NUM>. In the single domain display panel, all of the pixels <NUM> may have the same shape, the same size, and the same gradient. Referring to <FIG>, when the 3D display device <NUM> is manufactured using the single domain pixel structure, moiré does not occur in the cognitive frequency band.

The optical layer <NUM> may be a lenticular lens or a barrier having a periodical characteristic. For example, the optical layer <NUM> may be a lenticular lens in a vertically elongated shape as a semi-cylindrical lens. The optical layer <NUM> may control a direction of light incident from the display panel <NUM>.

In general, to maintain a panel thickness, a spacer (see <FIG>) may be provided between the pixels <NUM>. The spacer may be provided between the pixels <NUM> to support a load by difference between an internal pressure and an external pressure of the display panel <NUM>. Shapes of some pixels <NUM> or some subpixels in the corresponding pixel <NUM> may vary due to the spacer. Due to different pixel shapes, a pixel pattern repetition interval may increase, which may cause moiré in the cognitive frequency band. Hereinafter, moiré occurring due to the spacer is described with reference to <FIG> and a method of removing moiré occurring due to the pixel structure of <FIG> is described with reference to <FIG>. As illustrated in <FIG>, the spacer may be present within the display panel <NUM>.

<FIG> illustrates examples of describing a display panel including pixels in different patterns according to an example embodiment. In detail, <FIG> illustrates an example of a display panel <NUM> including spacers <NUM> and pixels <NUM>. Shapes of the pixels <NUM> included in the display <NUM> may vary due to the spacers <NUM>. For example, due the spacer <NUM>, shapes of R, G, B subpixels included in the respective pixels <NUM> may differ from each other in an odd row and an even row. For example, a size of an R subpixel included in the pixel <NUM> of an odd row may be less than those of G and B subpixels. Also, a size of an R subpixel included in the pixel <NUM> of an even row may be less than those of B and G subpixels. As described above with reference to <FIG>, in response to modifying a shape and/or a size of a pixel or a subpixel, a low frequency may be generated in a frequency domain and the generated low frequency may cause moiré in a cognitive frequency band.

Referring to <FIG>, a 3D display device <NUM> includes the display panel <NUM> and an optical layer <NUM>. The display panel <NUM> may include a plurality of pixels <NUM> and a plurality of spacers <NUM> configured to maintain a space for the plurality of pixels <NUM>.

<FIG> illustrates an example of moiré occurring in the cognitive frequency band when the 3D display device <NUM> is manufactured using the display panel <NUM> in the pixel structure of <FIG>. Such moiré occurring since a pixel shape varies due to the spacer <NUM> may be solved through a pixel structure of <FIG>.

<FIG> illustrate a display panel including pixels in the same pattern according to an example embodiment. For example, <FIG> illustrates an example of a display panel <NUM> including spacers <NUM> and pixels <NUM>. Shapes of the pixels <NUM> included in the display panel <NUM> may vary due to the spacers <NUM>.

According to an example embodiment, the pixels <NUM> are uniformly provided in the display panel <NUM> based on a pattern that is determined based on the spacers <NUM>. Here, the pattern may be represented using shapes, sizes, and gradients of R, G, and B subpixels included in an individual pixel. For example, each of the pixels <NUM> may have the same shape, size, and gradient in an even row and an odd row of the display panel <NUM> based on the determined pattern. Here, the pattern may refer to a pattern in which R, G, and B subpixels included in an individual pixel are arranged in line, have the same gradient, and sizes of the R subpixel and the B subpixel being less than that of the G subpixel.

The pixels <NUM> may have the same shape. For example, shapes of the pixels <NUM> corresponding to a single pattern formed by R, G, and B subpixels may be identical to each other. Also, the shapes of the pixels <NUM> may be determined based on a pattern by a combination of a plurality of subpixels included in an individual pixel and each of the pixels <NUM> in the display panel <NUM> may have the same pattern. For example, the shapes, sizes, and gradients of the R, G, and B subpixels respectively included in each of the pixels <NUM> may be identical.

As illustrated in <FIG>, when the repetition interval of a pattern is decreased, a frequency corresponding to a repetition interval of a pattern increases and may not be included in a cognitive frequency band of a user, for example, a cognitive frequency boundary of <NUM> cycle/degree. The repetition interval of the pattern may include at least one of a first interval at which the pattern is repeated in a horizontal direction, a second interval at which the pattern is repeated in a vertical direction, and a third interval at which the pattern is repeated in a direction corresponding to a combination of the horizontal direction and the vertical direction.

The pattern may include at least one pixel <NUM> and a structure of subpixels included in the pixel <NUM> may be determined based on a spacer placement space in the display panel <NUM>. In particular, a structure of the subpixels included in the pattern may be determined based on the spacer placement space that is maintained regardless of whether the spacer <NUM> is actually provided. For example, the structure of the subpixels <NUM> included in the pattern may be in a structure where a spacer placement space is empty at an upper end and/or lower end of an R subpixel and at an upper end and/or lower end of a B subpixel in which the spacer <NUM> may be placed, regardless of whether the spacer <NUM> is actually placed.

That is, at least one of the subpixels included in a pixel may have a size different from that of remaining pixels included in the pixel to secure the placement space. For example, a pixel may include an R subpixel with a first size, a G subpixel with a second size greater than the first size, and a B subpixel with the first size. According to an example embodiment, the pixel may include the R subpixel with the first size, the G subpixel with the second size less than the first size, and the B subpixel with a third size less than the first size and greater than the second size.

For example, the placement space of the spacer <NUM> may be prepared to be adjacent to the R subpixel and the B subpixel. In addition, the structure of subpixels included in the pattern may be determined based on various combinations of shapes, sizes, and gradients of subpixels.

According to an example embodiment, a pixel repetition interval may be reduced by adjusting a size of a subpixel in an area in which the spacer <NUM> is not actually placed. As described above, as the pixel repetition interval decreases the frequency increases, and thus moiré may be removed from the cognitive frequency band.

<FIG> illustrates an example in which the pixels <NUM> of the display panel <NUM> are in the same shape. <FIG> illustrates an example in which the pixels <NUM> of the display panel <NUM> are in different shapes. Here, an additional frequency component may be generated or present in addition to a pixel repetition interval based on an interval at which a new pattern is repeated due to the pixels in the different shape. Here, the new pattern may be, for example, a pattern configured based on a unit of n x m pixels where n and m denote positive integers and at least one of n and m is <NUM> or more. For example, when a lenticular lens is overlapped on a pixel structure having a new pattern, a new interference frequency may be generated in a frequency component due to the lenticular lens. Overlapping of the lenticular lens may represent a convolution effect in a frequency image. Accordingly, the simpler a frequency by a pixel repetition pattern becomes, the less an interference frequency is generated, which may decrease a probability that the interference frequency is included in the cognitive frequency band.

<FIG> illustrates an example of a frequency domain of the 3D display device <NUM> in the pixel structure of <FIG>. Referring to <FIG>, a moiré frequency is absent in the cognitive frequency band.

<FIG> is a flowchart illustrating an example of a simulation method of a 3D display device according to an example embodiment. A process of performing a simulation to prevent or reduce occurrence of moiré without directly attaching a lens using a simulation apparatus according to an example embodiment is described with reference to <FIG>. Referring to <FIG>, in operation <NUM>, the simulation apparatus may generate a panel image to provide a 3D image to which an optical characteristic is applied. Here, the 3D image may include a left image and a right image as images that are provided to both eyes of a user, for example, a viewer. The 3D image may be an input image, for example, augmented reality (AR) content. The panel image may be an image represented on a display panel of the 3D display device and may be generated based on positions of eyes of the user and direction information of light to provide a 3D image to the user. For the simulation operation of <FIG>, the simulation apparatus may generate a white image in which all of the pixels are ON as the panel image.

In operation <NUM>, the simulation apparatus may change an optical characteristic, for example, a pitch and/or angle, of a lens of the 3D display device. In operation <NUM>, the simulation apparatus may generate an overlapping image by applying the optical characteristic changed in operation <NUM>. The overlapping image may be an image that is formed at both eyes of the user. For example, when the 3D image is provided from the 3D display device, the simulation apparatus may capture the overlapping image.

In operation <NUM>, the simulation apparatus may transform the overlapping image to an image of a frequency domain. In operation <NUM>, the simulation apparatus may determine whether a moiré frequency included in the image of the frequency domain is present within a cognitive frequency band. For example, when the moiré frequency included in the frequency domain image is less than a cognitive frequency boundary in operation <NUM>, the simulation apparatus may again change the optical characteristic of the lens of the display panel in operation <NUM>.

On the contrary, when moiré within the cognitive frequency band is determined to be absent in the image of the frequency domain in operation <NUM>, the simulation apparatus may determine the corresponding optical characteristic as the optical characteristic of the lens in operation <NUM>.

<FIG> illustrates an example of describing a structure and an operation of a 3D HUD device according to an example embodiment. Referring to <FIG>, a 3D HUD device <NUM> may include a display panel <NUM>, a picture generation unit (PGU) <NUM> including a backlight unit (BLU) <NUM>, and an optical layer <NUM>.

The display panel <NUM> includes a plurality of pixels and a plurality of spacers configured to maintain a space for the plurality of spacers. The pixels are uniformly provided in the display panel <NUM> based on a pattern that is determined based on the plurality of spacers, and a frequency corresponding to a repetition interval of the pattern is not included in a cognitive frequency band of a user. The description made above with respect to the display panel <NUM> of <FIG> may be applicable to the display panel <NUM>.

The BLU <NUM> may uniformly emit light at the rear of the display panel <NUM>.

To provide a 3D image <NUM> to the user through the optical layer <NUM>, the PGU <NUM> generates a panel image <NUM> displayed on the display panel <NUM> based on positions of both eyes of the user. The PGU <NUM> may include at least one processor.

<FIG> illustrate related examples of describing an occurrence reason of moiré to be solved according to an example embodiment. <FIG> illustrates an example of representing an image displayed on a display panel in a space domain and <FIG> illustrates an example of transforming the space domain of the image of <FIG> to a frequency domain. The overlapping of two images may be convolution of two frequency transformed images in the frequency domain.

An image of <FIG> may have a ±f1 vector in the frequency domain, and an image of <FIG> may have a ±f2 vector in the frequency domain. Here, the ±f1 vector and the ±f2 vector may represent periodic patterns of the respective images. The periodic pattern may be represented as moiré in the mage.

An image of <FIG> may further have an f1 + f2 vector, a -f1 - f2 vector, an f1 - f2 vector, and an f2 - f1 vector, in addition to the ±f1 vector and the ±f2 vector as convolution of the two vectors ±f1 and ±f2 in the frequency domain. The f1 + f2 vector and the -f1 - f2 vector may have a high frequency compared to an original image, and the f1 - f2 vector and the f2 - f1 vector may have a low frequency compared to the original image. Here, when the f1 - f2 vector and the f2 - f1 vector are present in a cognitive frequency band, a stripped pattern may appear in a direction corresponding to the f1 - f2 vector and the f2 - f1 vector. A frequency vector may have a direction and a magnitude. A vector direction represents a direction of the striped pattern and is well visible at eyes of a person as a frequency of moiré becomes lower. Also, the frequency vector may have an impulse indicating a brightness level of the image.

The example embodiments described herein may be implemented using hardware components, software components, and/or a combination thereof. For example, the apparatuses, methods, processing device, and components described herein may be implemented using one or more general-purpose or special purpose computers, such as, for example, a processor, a controller and an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a programmable logic unit (PLU), a microprocessor, or any other device capable of responding to and executing instructions in a defined manner. The processing device may run an operating system (OS) and one or more software applications that run on the OS. The processing device also may access, store, manipulate, process, and create data in response to execution of the software. For purpose of simplicity, the description of a processing device is used as singular, however, one skilled in the art will be appreciated that a processing device may include multiple processing elements and/or multiple types of processing elements. For example, a processing device may include multiple processors or a processor and a controller. In addition, different processing configurations are possible, such as parallel processors.

Claim 1:
A display panel comprising:
a pattern having a plurality of pixels (<NUM>, <NUM>) uniformly provided in a horizontal and vertical direction, each of the pixels (<NUM>, <NUM>) having a same shape, wherein each individual pixel (<NUM>, <NUM>) includes a row of subpixels in an order of one red, R, subpixel,
followed by one green, G, subpixel, followed by one blue, B, subpixel, the G subpixel being located between the R subpixel and the B subpixel in the row of subpixels within each individual pixel, and sizes of the R subpixel and the B subpixel being less than the size of the G subpixel; and
a plurality of placement spaces (<NUM>, <NUM>) provided between the plurality of pixels (<NUM>, <NUM>),
wherein the plurality of pixels (<NUM>, <NUM>) are uniformly provided in the display panel (<NUM>, <NUM>, <NUM>, <NUM>) based on a pattern corresponding to the plurality of placement spaces (<NUM>, <NUM>), and
wherein the pattern comprises a plurality of units of four pixels in a <NUM> × <NUM> pixel structure forming a gap within a center of the <NUM> × <NUM> pixel structure by using the reduced size of the R subpixels and the B subpixels of said four pixels for locating the plurality of placement spaces, thereby achieving that a frequency corresponding to a repetition interval of the pattern is outside of a cognitive frequency band that is visible to a user.