Subpixel rendering for display panels including multiple display regions with different pixel layouts

Abstract

To provide a display driver to perform subpixel rendering for display panels having low-pixel density regions or regions with low pixels-per-inch (PPI).SOLUTION: A display driver 110 includes an image processing circuit 140 and a driver circuit 150. The image processing circuit 140 is configured to: receive input image data corresponding to an input image; generate first subpixel rendered data from a first part of the input image data corresponding to a first display region 122 by using a first setting; and generate second subpixel rendered data from a second part corresponding to a second display region 124 using a second setting different from the first setting. The driver circuit 150 is configured to update the first display region 122 of a display panel based at least in part on the first subpixel rendered data, and update the second display region 124 of the display panel based at least in part on the second subpixel rendered data.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This application claims the benefit under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 63 / 248,893, filed September 27, 2021. U.S. Provisional Patent Application No. 63 / 248,893 is incorporated herein by reference in its entirety.

[0002] The present disclosure relates generally to the field of display panels, and more particularly to sub-pixel rendering for display panels. [Background technology]

[0003] Some display panels may have multiple display areas with different pixel layouts. One example is a display panel that supports the inclusion of under-display (or under-screen) optics such as cameras, proximity sensors, and other optical sensors. Mobile device manufacturers attempt to optimize the available display area by eliminating any non-display elements on the surface of the device. Elements, including but not limited to cameras and proximity sensors, require dedicated space outside the display area, which limits the available display area. One option is to place optical elements, such as cameras or other optical sensors, below the display panel. In one example, a front-facing camera or other optical element may be placed below the display surface to enable taking photos in "selfie mode." In some embodiments, pixels above the under-display optics may be spaced more widely than in other areas of the display panel to allow sufficient light to pass through the pixels and reach the under-display optics. These widely spaced pixel regions are sometimes referred to as low pixel density regions or low pixels per inch (PPI) regions. Summary of the Invention

[0004] This Summary is provided to introduce a selection of concepts in a concise form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0005] In one or more embodiments, a display driver is provided. The display driver includes an image processing circuit and a driver circuit. The image processing circuit is configured to receive input image data corresponding to an input image. The image processing circuit is further configured to generate first sub-pixel rendered data from a first portion of the input image data corresponding to a first display region of the display panel using a first setting and to generate second sub-pixel rendered data from a second portion of the input image data corresponding to a second display region of the display panel using a second setting different from the first setting. The first setting is for a first pixel layout of the first display region and the second setting is for a second pixel layout of the second display region. The first pixel layout is different from the second pixel layout. The driver circuit is configured to update the first display region of the display panel based at least in part on the first sub-pixel rendered data and to update the second display region of the display panel based at least in part on the second sub-pixel rendered data.

[0006] In one or more embodiments, a display device is provided. The display device includes a display panel and a display driver. The display panel includes a first display region having a first pixel layout and a second display region having a second pixel layout different from the first pixel layout. The display driver is configured to receive input image data corresponding to an input image to be displayed on the display panel. The display driver is further configured to generate first sub-pixel rendered data from a first portion of the input image data corresponding to the first display region using a first setting for the first pixel layout of the first display region, and to generate second sub-pixel rendered data from a second portion of the input image data corresponding to the second display region using a second setting for the second pixel layout of the second display region, the second setting being different from the first setting. The display driver is further configured to update the first display region of the display panel based at least in part on the first sub-pixel rendered data and to update the second display region of the display panel based at least in part on the second sub-pixel rendered data.

[0007] In one or more embodiments, a method for driving a display panel is provided. The method includes receiving input image data corresponding to an input image. The method further includes generating first sub-pixel rendered data from a first portion of the input image data corresponding to a first display region of the display panel using a first setting, and generating second sub-pixel rendered data from a second portion of the input image data corresponding to a second display region of the display panel using a second setting different from the first setting. The first setting is for a first pixel layout of the first display region, and the second setting is for a second pixel layout of the second display region. The first pixel layout is different from the second pixel layout. The method further includes updating the first display region of the display panel based at least in part on the first sub-pixel rendered data, and updating the second display region of the display panel based at least in part on the second sub-pixel rendered data.

[0008] Other aspects of the embodiments will be apparent from the following description and appended claims. [Brief explanation of the drawings]

[0009] So that the above-mentioned features of the present disclosure can be understood in detail, a more particular description of the present disclosure, briefly summarized above, may be had with reference to embodiments, some of which are illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only exemplary embodiments and should not be considered as limiting the scope of the invention, since the present disclosure admits of other equally effective embodiments.

[0010] [Figure 1] FIG. 1 illustrates an exemplary configuration of a display system according to one or more embodiments.

[0011] [Figure 2] FIG. 2 illustrates an exemplary configuration of a display system according to one or more embodiments.

[0012] [Figure 3] FIG. 3 illustrates an exemplary embodiment of a display panel that includes a low pixel density region and a standard pixel density region.

[0013] [Figure 4] FIG. 4 is a block diagram illustrating a display system according to another embodiment.

[0014] [Figure 5] FIG. 5 illustrates an exemplary input image corresponding to input image data, according to one or more embodiments.

[0015] [Figure 6] FIG. 6 illustrates an example pixel layout for a first display area and a second display area of ​​a display panel, according to one or more embodiments.

[0016] [Figure 7A] FIG. 7A illustrates an exemplary configuration of a pixel according to one or more embodiments.

[0017] [Figure 7B] FIG. 7B illustrates another exemplary configuration of a pixel according to one or more embodiments.

[0018] [Figure 8] FIG. 8 is a diagram illustrating an exemplary mapping of input pixels of an input image to red (R), green (B), and blue (B) subpixels of a display panel, according to one or more embodiments.

[0019] [Figure 9] FIG. 9 illustrates an exemplary R reference region defined for the R sub-pixels of a display panel, according to one or more embodiments.

[0020] [Figure 10] FIG. 10 illustrates exemplary calculations performed in subpixel rendering to determine the gray level of the R subpixel, in accordance with one or more embodiments.

[0021] [Figure 11] FIG. 11 illustrates exemplary calculations performed in subpixel rendering to determine the gray level of the R subpixel, in accordance with one or more embodiments.

[0022] [Figure 12] FIG. 12 illustrates an example R reference region defined for a border R sub-pixel, according to one or more embodiments.

[0023] [Figure 13] FIG. 13 illustrates an example R reference region defined for border R sub-pixels, according to one or more embodiments.

[0024] [Figure 14A]FIG. 14A illustrates an exemplary R reference region defined for an R sub-pixel, according to one or more embodiments.

[0025] [Figure 14B] FIG. 14B illustrates exemplary calculations performed in sub-pixel rendering to determine the gray level of the R sub-pixel, according to one or more embodiments.

[0026] [Figure 15A] FIG. 15A illustrates an exemplary R reference region defined for an R subpixel, according to another embodiment.

[0027] [Figure 15B] FIG. 15B illustrates exemplary calculations performed in sub-pixel rendering to determine the gray level of the R sub-pixel, according to one or more embodiments.

[0028] [Figure 16] FIG. 16 illustrates an exemplary B reference region defined for a B subpixel of a display panel, according to one or more embodiments.

[0029] [Figure 17] FIG. 17 illustrates an exemplary G reference region defined for a G subpixel of a display panel, according to one or more embodiments.

[0030] [Figure 18] FIG. 18 illustrates exemplary calculations performed in sub-pixel rendering to determine the gray level of a G sub-pixel, according to one or more embodiments.

[0031] [Figure 19] FIG. 19 illustrates an exemplary G reference region defined for boundary G sub-pixels, according to one or more embodiments.

[0032] [Figure 20]FIG. 20 illustrates exemplary steps for driving a display panel according to one or more embodiments.

[0033] For ease of understanding, the same reference numerals have been used, where possible, to designate identical elements common to the figures. It is anticipated that elements disclosed in one embodiment may be beneficially used in other embodiments without specific mention. Reference numerals may be supplemented with subscripts to distinguish identical elements from one another. The drawings referred to herein should not be understood as being drawn to scale unless specifically noted. Also, for clarity of presentation and explanation, the drawings are often simplified, omitting details or components. The drawings and discussion serve to explain the principles discussed below, with like numerals indicating like elements. DETAILED DESCRIPTION OF THE INVENTION

[0034] The following detailed description is merely exemplary in nature and is not intended to be limiting as to the disclosure and its application and uses.Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding background, summary or the following detailed description.

[0035] A display panel may have two or more display areas with different pixel layouts (or geometries). Differences in pixel layouts may include differences in pixel density (sometimes measured as pixels per inch (PPI)) and / or differences in spacing between pixels. Differences in pixel layouts may additionally or alternatively include differences in one or more of the size, configuration, arrangement, and number of subpixels within each pixel.

[0036] In one exemplary implementation, the display panel may include a low pixel density region beneath which under-display optics (e.g., a camera, proximity sensor, or other optical sensor) are disposed. The low pixel density region may have a lower pixel density than pixel density regions in other portions of the active area of ​​the display panel, which may be referred to as standard pixel density regions. The low pixel density region may be configured to allow sufficient ambient light to reach the under-display optics. In one implementation, an under-display camera is disposed beneath the low pixel density region and configured to capture images through the low pixel density region.

[0037] In some embodiments, driving or updating the display panel based on the input image data may include performing sub-pixel rendering on the input image data. Sub-pixel rendering is a technique for increasing the apparent resolution of a display device by rendering sub-pixels (e.g., red (R), green (G), and blue (B) sub-pixels) based on the physical pixel layout. Sub-pixel rendering may determine or calculate the gray level of each sub-pixel based on the input image data and the physical pixel layout.

[0038] One problem is that in embodiments where a display panel has two or more display regions with different pixel layouts, sub-pixel rendering can cause image artifacts, distortions, and / or color shifts. This disclosure provides various techniques for mitigating image artifacts, distortions, and / or color shifts that may occur due to sub-pixel rendering in display images displayed on display panels with display regions with different pixel layouts.

[0039] In one or more embodiments, a display driver includes a pixel processing circuit and a driver circuit. The image processing circuit is configured to receive input image data corresponding to an input image. The image processing circuit is further configured to generate first sub-pixel rendered data from a first portion of the input image data corresponding to a first display region of the display panel using a first setting and to generate second sub-pixel rendered data from a second portion of the input image data corresponding to a second display region of the display panel using a second setting. The first setting is for a first pixel layout of the first display region and the second setting is for a second pixel layout of the second display region. The first pixel layout is different from the second pixel layout and the first setting is different from the second setting. The driver circuit is configured to update the first display region of the display panel based at least in part on the first sub-pixel rendered data and to update the second display region of the display panel based at least in part on the second sub-pixel rendered data. Using the first and second settings for the first and second pixel layouts, respectively, may effectively mitigate distortion and / or color shift that may be caused by sub-pixel rendering. Detailed embodiments of the present disclosure are described below.

[0040] 1 illustrates an exemplary configuration of a display system 100 according to one or more embodiments. In the illustrated embodiment, display system 100 includes a display driver 110 and a display panel 120. Examples of display panel 120 include organic light emitting diode (OLED) display panels, micro light emitting diode (LED) panels, liquid crystal display (LCD) panels, and display panels implementing various other suitable display technologies.

[0041] Display driver 110 is configured to drive or update display panel 120 based on image data 112 received from source 130. Image data 112 corresponds to an input image to be displayed on display panel 120. Image data 112 may include pixel data for each pixel of the displayed image. The pixel data for each pixel may include a shade of each color (e.g., red (R), green (G), and blue (B)) of the pixel. In an embodiment where image data 112 is in RGB format, the pixel data for each pixel includes a shade of red, green, and blue (which may hereinafter be referred to as an R shade, a G shade, and a B shade, respectively). Source 130 may be a processor (e.g., an application processor and a central processing unit (CPU)), an external controller, a host, or other device configured to provide image data 112.

[0042] The display panel 120 includes multiple display regions having different pixel layouts. In the illustrated embodiment, the display panel 120 includes a first display region 122 having a first pixel layout and a second display region 124 having a second pixel layout that is different from the first pixel layout. The first and second pixel layouts may have different pixel densities (e.g., measured in pixels per inch (PPI)). In some embodiments, the pixel density of the second display region 124 is lower than the pixel density of the first display region 122, and one or more under-display optics (e.g., a camera, proximity sensor, or other optical sensor) are disposed below the second display region 124. The lower pixel density of the second display region 124 may allow sufficient light to pass through the second display region 124 to reach the under-display optics. The first and second pixel layouts may also, or instead, differ in the size, configuration, arrangement, and / or number of subpixels in each pixel. In other embodiments, the display panel 120 may further include one or more display areas having a pixel layout different from the first pixel layout and the second pixel layout.

[0043] In one or more embodiments, the display driver 110 includes an image processing circuit 140, a driver circuit 150, and a register circuit 160. The image processing circuit 140 is configured to perform image processing on image data 112 received from the source 130 to generate voltage data specifying the voltage levels of data voltages to be used to update each subpixel of the display panel 120. As discussed in detail below, the image processing includes subpixel rendering. The image processing may also include color adjustment, scaling, overshoot / undershoot driving, gamma conversion, and other image processing. The driver circuit 150 is configured to generate data voltages based on the voltage data received from the image processing circuit 140 and update each subpixel of the display panel 120 with the generated data voltages. The register circuit 160 is configured to store settings for the image processing performed by the image processing circuit 140.

[0044] The image processing circuit 140 includes a subpixel rendering (SPR) circuit 142. The image processing circuit 140 is configured to provide input image data to the SPR circuit 142. Here, the input image data is based on the image data 112 received from the source 130. The input image data may be the image data 112 itself, or may be image data generated by performing desired image processing (e.g., color adjustment, scaling, and other image processing) on ​​the image data 112. The SPR circuit 142 is configured to perform subpixel rendering on the input image data.

[0045] In one or more embodiments, SPR circuitry 142 is configured to perform subpixel rendering using different settings for first display region 122 and second display region 124. Register circuitry 160 is configured to store a first setting 162 for a first pixel layout for first display region 122 and a second setting 164 for a second pixel layout for second display region 124. First setting 162 may specify a particular set of one or more operations (e.g., including one or more algorithms and / or calculations) for subpixel rendering to be performed for first display region 122, and second setting 164 may specify a particular set of one or more operations (e.g., including one or more algorithms and / or calculations) for subpixel rendering to be performed for second display region 124. First setting 162 and second setting 164 are described in more detail below. The second pixel layout of second display area 124 is different from the first pixel layout of first display area 122 , so that first setting 162 is different from second setting 164 .

[0046] The SPR circuit 142 is configured to generate first sub-pixel rendered data by performing sub-pixel rendering on a first portion of the input image data corresponding to the first display region 122 using a first setting 162, and to generate second sub-pixel rendered data from a second portion of the input image data corresponding to the second display region 124 of the display panel using a second setting 164. The image processing circuit 140 is further configured to generate first voltage data for the first display region 122 based on the first sub-pixel rendered data and to generate second voltage data for the second display region 124 based on the second sub-pixel rendered data. The driver circuit 150 is configured to update the sub-pixels of the first display region 122 based at least in part on the first voltage data for the first display region 122 and to update the sub-pixels of the second display region 124 based at least in part on the second voltage data for the second display region 124. Because the first voltage data for the first display region 122 is based on the first sub-pixel rendered data, the driver circuit 150 is configured to update the first display region 122 of the display panel 120 based at least in part on the first sub-pixel rendered data. Similarly, because the second voltage data for the second display region 124 is based on the second sub-pixel rendered data, the driver circuit 150 is configured to update the second display region 124 of the display panel 120 based at least in part on the first sub-pixel rendered data. By using the first setting 162 and the second setting 164 for the first display region 122 and the second display region 124, respectively, the SPR circuit 142 can achieve improved sub-pixel rendering for the first display region 122 and the second display region 124, effectively mitigating distortion and / or color shift that may occur due to the sub-pixel rendering.

[0047] FIG. 2 illustrates an exemplary configuration of a display system 200 according to one or more embodiments. Display system 200 may be an embodiment of display system 100 of FIG. 1. Display system 200 includes a display panel 270, which may be an embodiment of display panel 120 of FIG. 1. In the illustrated embodiment, display panel 270 includes a low pixel density region 271, which has a pixel density lower than the pixel density of a region of display panel 270 outside low pixel density region 271. The region outside low pixel density region 271 has a standard pixel density and may be referred to as a standard pixel density region. The standard pixel density region may be an embodiment of first display region 122 of FIG. 1, and low pixel density region 271 may be an embodiment of second display region 124 of FIG. 1. In the standard pixel density region, the pixel density may be the same as or lower than the pixel density of an input image provided to display system 200 in the form of input image data 210.

[0048] Input image data 210 is input to SPR circuit 220 from host device 205. Host device 205 may be one embodiment of source 130 in FIG. 1. In SPR circuit 220, input image data 210 is coupled to low pixel density region SPR circuit 222 and standard pixel density region SPR circuit 224. Input image data 210 is coupled to register circuit 230. Register circuit 230 may provide setting 231 (which may be one embodiment of second setting 164 in FIG. 1) to configure low pixel density region SPR circuit 222. Register circuit 230 may provide setting 232 (which may be one embodiment of first setting 162 in FIG. 1) to configure standard pixel density region SPR circuit 224. Register circuit 230 may decode input image data 210 and, based on the decoded pixel position data, provide position setting 233 to combining circuit 280 to indicate the shape and position of low pixel density region 271. One possible value for the position setting 233 may indicate that the input image data 210 corresponds to a location in the low pixel density region 271. A second possible value for the position setting 233 may indicate that the input image data 210 corresponds to a location in a standard pixel density region outside the low pixel density region 271 of the display panel 270. A third possible value for the position setting 233 may indicate that the input image data 210 corresponds to a boundary between the low pixel density region 271 and the standard pixel density region.

[0049] The low pixel density region SPR circuit 222 may receive the input image data 210 and perform image processing based on the settings 231 to generate a low pixel density region output 223. The image processing performed in the low pixel density region SPR circuit 222 may include subpixel rendering for the low pixel density region 271. The settings 231 may specify a specific algorithm or image operation to be performed in the low pixel density region SPR circuit 222. The low pixel density region output 223 may include information for driving subpixels in the low pixel density region 271 using the received input image data 210. The low pixel density region SPR circuit 222 may apply a thinning or averaging algorithm to map a larger number of received pixels of the input image data 210 to a smaller number of pixels in the low pixel density region 271 of the display panel 270. The low pixel density region output 223 may include subpixel rendered data for the low pixel density region 271.

[0050] The standard pixel density region SPR circuit 224 may receive input image data 210 and perform image processing based on settings 232 to generate a standard pixel density region output 225. The image processing performed in the standard pixel density region SPR circuit 224 may include subpixel rendering for the standard pixel density region. The settings 232 may specify a specific algorithm or image operation to be performed in the standard pixel density region SPR circuit 224. The standard pixel density region output 225 may include information for driving subpixels using the received input image data 210. The standard pixel density region SPR circuit 224 may apply any desired image processing algorithm to the input image data 210 to generate a desired image response in a region outside the low pixel density region 271 of the display panel 270 having a standard pixel density. The standard pixel density region output 225 may include subpixel rendered data for the standard pixel density region.

[0051] The combiner circuit 280 receives as inputs the low pixel density region output 223, the standard pixel density region output 225, and the position setting 233. For pixel locations where the position setting 233 is set to a value indicative of a pixel location within the low pixel density region 271, the combiner circuit 280 may output the low pixel density region output 223 to the driver 290. For pixel locations where the position setting 233 is set to a value indicative of a pixel location within the standard pixel density region, the combiner circuit 280 may output the standard pixel density region output 225 to the driver 290. For pixel locations where the position setting 233 is set to a value indicative of a pixel location on the boundary between the low pixel density region 271 and the standard pixel density region, the combiner circuit 280 may perform special image processing to reduce visible artifacts at the boundary between the low pixel density region 271 and the standard pixel density region.

[0052] 3 illustrates an exemplary embodiment of a display panel 300 including a low pixel density region 320 and a standard pixel density region 310. Display panel 300 may be one embodiment of display panel 120 of FIG. 1. The density of pixels in standard pixel density region 310 may be the same as or lower than that of the input image. In standard pixel density region 310, individual pixels are shown as squares with rounded corners, including, but not limited to, pixels 311, 312, 313a, 313b, 313c, 313d, 313e, and 313f. Pixels in standard pixel density region 310 may also be other shapes, such as, but not limited to, circles, hexagons, rectangles, or other regular geometric shapes.

[0053] In low pixel density region 320, individual pixels are spaced further apart than in standard pixel density region 310. Pixels 321 and 322 are separated horizontally by a distance three times the distance between pixels 311 and 312. This specific example should not be considered limiting to embodiments having other distances between pixels. Pixels in low pixel density region 320 may be separated by distances greater or less than the separation distance illustrated in FIG. 3 .

[0054] Pixel 324 of low pixel density region 320 is shown alongside an embodiment in which multiple standard pixel density pixels are to be processed to generate a single pixel of low pixel density region 320. These six pixels (323a, 323b, 323c, 323d, 323e, and 323f) represent input image information processed in low pixel density region SPR circuit 222 to generate information for driving subpixels with desired image data corresponding to pixel 324. These six pixels may be present in the input image information but may not be physically present in display panel 270, but are shown here to demonstrate the concept of the display system. In some embodiments, low pixel density region SPR circuit 222 may thin out the standard pixel density pixels to convert the information of the six standard pixel density pixels into subpixel information for applying input image data 210 to the single low pixel density pixel 324. In other embodiments, the low pixel density region SPR circuit 222 may perform an averaging operation on the standard pixel density data to convert the information from six pixels into sub-pixel information for applying the input image data 210 to a single low pixel density pixel 324. In other embodiments, the low pixel density region SPR circuit 222 may use other signal processing algorithms to convert the information from six standard pixel density pixels into sub-pixel information corresponding to the pixel 324.

[0055] Pixel 326 represents another embodiment of the relationship between the density of standard-density pixels and the pixels of low-density region 320. Pixel 326 overlaps with eight standard-density pixels, shown as input pixels 325a, 325b, 325c, 325d, 325e, 325f, 325g, and 325h. In this and other embodiments, low-density region SPR circuit 222 may convert the eight standard-density pixels into a single pixel 326. This conversion may include a thinning calculation, an averaging operation, or other algorithm to represent the eight standard-density pixels 325a, 325b, 325c, 325d, 325e, 325f, 325g, and 325h as a single low-density pixel 326.

[0056] Other embodiments of the display system may include pixels of different shapes than those illustrated herein, including, but not limited to, rectangular, square, hexagonal, or other regular polygonal shapes. The conversion of a plurality of standard-density pixels to a lower density in the low-pixel-density region 320 may involve calculations of a wide range of input image pixels. The calculations may involve more or fewer pixels than those illustrated herein. A plurality of standard-density pixels may overlap a single pixel in the low-pixel-density region 320 in a different pattern than illustrated in these examples to continue implementing the disclosed display system.

[0057] Pixels 313a, 313b, 313c, 313d, 313e, 313f, 321, and 322 are located at the boundary between low pixel density region 320 and standard pixel density region 310. Additional image processing may be applied to these boundary pixels. In some embodiments, pixel information for the boundary pixels may be averaged over neighboring pixels to smooth discontinuities. In other embodiments, pixel information for the boundary pixels may be filtered using a window function. The combining circuit 280 may adjust the luminance values ​​of the boundary pixels based on the position setting 233.

[0058] 4 is a block diagram illustrating a display system 400 according to another embodiment. The display system 400 may be an embodiment of the display system 100 of FIG. 1. In the illustrated embodiment, the display system 400 includes a display driver 410 and a display panel 420. The display driver 410 is configured to drive or update the display panel 420 based on image data 412 received from a source 430. The source 430 may be a processor (e.g., an application processor and a central processing unit (CPU)), an external controller, a host, or another device configured to provide the image data 412. The image data 412 may include pixel data for each pixel of an input image to be displayed on the display panel 420. The pixel data for a pixel may include a shade of each color (e.g., red, green, and blue) of the pixel.

[0059] The display panel 420 includes a first display area 422 having a first pixel layout and a second display area 424 having a second pixel layout that is different from the first pixel layout. In the illustrated embodiment, the pixel density of the second display area 424 is lower than the pixel density of the first display area 422. In some embodiments, one or more under-display optics (not shown) may be provided below the second display area 424, while the second display area 424 is configured to allow sufficient light to pass through the second display area 424 to reach the under-display optics. Examples of under-display optics include cameras, proximity sensors, and other optical sensors.

[0060] In one or more embodiments, the display driver 410 includes an interface (I / F) circuit 435, an image processing circuit 440, a driver circuit 450, a register circuit 460, and an area definition decoder 470. The image processing circuit 440, the driver circuit 450, and the register circuit 460 may be embodiments of the image processing circuit 140, the driver circuit 150, and the register circuit 160 in FIG. 1, respectively.

[0061] The interface circuit 435 is configured to receive image data 412 from the source 430 and forward the image data 412 to the image processing circuit 440. The interface circuit 435 may further be configured to receive setting updates 414 from the source 430 and update the settings stored in the register circuit 460 as directed by the setting updates 414.

[0062] Image processing circuitry 440 is configured to perform desired image processing on image data 412 received from source 430 to generate voltage data 416. Voltage data 416 specifies the voltage levels of the data voltages to be used to update each subpixel of display panel 420. In one or more embodiments, the image processing performed by image processing circuitry 440 includes subpixel rendering. The image processing may also include color adjustment, scaling, overshoot / undershoot driving, gamma conversion, and other image processing.

[0063] The driver circuit 450 is configured to update each sub-pixel of the display panel 420 based on the voltage data 416 received from the image processing circuit 440. In one implementation, the driver circuit 450 may be configured to generate and supply a data voltage to each sub-pixel of the display panel 420 such that the data voltage has a voltage level as specified by the voltage data 416.

[0064] The register circuit 460 is configured to store settings used in image processing to be performed by the image processing circuit 440. In the illustrated embodiment, the settings stored in the register circuit 460 include a first setting 462, a second setting 464, and a display area definition 466. The first setting 462 may specify a specific algorithm and / or calculation for sub-pixel rendering to be performed for the first display area 422, and the second setting 464 may specify a specific algorithm and / or calculation for sub-pixel rendering to be performed for the second display area 424. The display area definition 466 includes information defining the first display area 422 and the second display area 424. The display area definition 466 may include the shape, position, dimensions (e.g., width and height), and / or other spatial information of the second display area 424.

[0065] Register circuit 460 may also be configured to store border compensation coefficients 468 used in sub-pixel rendering for sub-pixels at the boundary between first display area 422 and second display area 424. In one or more embodiments, selected ones of border compensation coefficients 468 may be applied in sub-pixel rendering for each sub-pixel located at the boundary between first display area 422 and second display area 424 to mitigate image artifacts at the boundary. Details of the use of border compensation coefficients 468 in sub-pixel rendering are described in more detail below.

[0066] The region definition decoder 470 is configured to decode the display region definition 466 to generate a region indication signal 472. The region indication signal 427 indicates whether a subpixel of interest in image processing performed by the image processing circuit 440 is located in the first display region 422 or the second display region 424. The region indication signal 427 may be one embodiment of the position setting 233 described in connection with FIG.

[0067] In one or more embodiments, the image processing circuit 440 includes an SPR circuit 442 and a gamma circuit 444. The image processing circuit 440 is configured to provide input image data to the SPR circuit 442, where the input image data is based on image data 412 received from the source 430. The input image data may be the image data 412 itself or image data generated by performing desired image processing (e.g., color adjustment, scaling, and other image processing) on ​​the image data 412. The SPR circuit 442 is configured to perform subpixel rendering on the input image data.

[0068] In the illustrated embodiment, the SPR circuit 442 includes a first display area SPR circuit 445 , a second display area SPR circuit 446 , and a combining circuit 447 .

[0069] The first display area SPR circuit 445 is configured to receive a first portion of the input image data corresponding to the first display area 422, and to perform subpixel rendering on the first portion of the input image data based on the first setting 462 to generate first subpixel rendered data 448. The first subpixel rendered data 448 may include grayscales of subpixels in the first display area 422.

[0070] The second display area SPR circuit 446 is configured to receive a second portion of the input image data corresponding to the second display area 424 and perform subpixel rendering on the second portion of the input image data based on the second setting 464 to generate second subpixel rendered data 449. The second subpixel rendered data 449 may include grayscales of subpixels in the second display area 424.

[0071] The combining circuit 447 is configured to combine the first sub-pixel rendered data 448 and the second sub-pixel rendered data to generate the resulting sub-pixel rendered data 415. The combining circuit 447 may be configured, based on the region indication signal 472, to output the first sub-pixel rendered data 448 as the resulting sub-pixel rendered data 415 for sub-pixels in the first display region 422 and to output the second sub-pixel rendered data 449 as the resulting sub-pixel rendered data 415 for sub-pixels in the second display region 424. The combining circuit 447 may further be configured to apply, for each sub-pixel at a boundary between the first display region 422 and the second display region 424, a selected one of the boundary compensation coefficients 468 to the grayscale indicated by the first sub-pixel rendered data 448 or the second sub-pixel rendered data 449 in generating the resulting sub-pixel rendered data 415. The selection of the boundary compensation coefficient 468 for each boundary sub-pixel may be based on the position of the sub-pixel. As will be explained in more detail below, a border compensation factor 468 may be applied to mitigate image artifacts that may occur at the border between first display area 422 and second display area 424 .

[0072] Gamma circuitry 444 is configured to perform gamma conversion on resulting sub-pixel rendered data 415 to generate voltage data 416. In embodiments in which first display area 422 and second display area 424 have different pixel densities, gamma conversion may be performed using different “gamma curves” for first display area 422 and second display area 424. As used herein, a “gamma curve” refers to the correspondence between the gray levels indicated by resulting sub-pixel rendered data 415 and the voltage levels indicated by voltage data 416. In one embodiment, the gamma curves for first display area 422 and second display area 424 are determined depending on the ratio of the pixel density of second display area 424 to the pixel density of first display area 422. For example, in an embodiment in which the pixel density of second display area 424 is X times (X is a number between 0 and 1, not including 0) that of first display area 422, the gamma curves of first display area 422 and second display area 424 are determined such that, for a fixed grayscale and a fixed color, the luminance of a subpixel in second display area 424 is 1 / X times the luminance of a subpixel in first display area 422. A gamma curve determined in this manner reduces or eliminates the difference in luminance between the images displayed in first display area 422 and second display area 424.

[0073] The following provides a detailed description of exemplary sub-pixel rendering performed by the SPR circuitry 442 in accordance with one or more embodiments.

[0074] FIG. 5 illustrates an exemplary input image corresponding to input image data provided to SPR circuit 442, according to one or more embodiments. The input image is indicated by the reference numeral 500. Note that the input image data may be raw image data 412 or may be image data generated by performing desired image processing on image data 412. In the illustrated embodiment, input image 500 includes a matrix of input pixels 502. In the illustrated embodiment, each input pixel 502 is defined as a square. In other embodiments, input pixels 502 may be defined as different shapes, such as rectangles, diamonds, parallelograms, and other shapes determined so that input pixels 502 fill the entire input image. The input image data may include red, green, and blue gradations (which may be referred to as R gradations, G gradations, and B gradations, respectively) for each input pixel 502.

[0075] FIG. 6 illustrates an exemplary pixel layout of the first display region 422 and the second display region 424 of the display panel 420 in accordance with one or more embodiments. In the illustrated embodiment, the first display region 422 includes pixels 600A and 600B, each including one red (R) subpixel 602R, two green (G) subpixels 602G, and one blue (B) subpixel 602B. FIGS. 7A and 7B illustrate exemplary configurations of the pixels 600A and 600B, respectively, in accordance with one or more embodiments. As illustrated in FIG. 7A, the left column of the pixel 600A includes a B subpixel 602B and an R subpixel 602R, and the right column includes two G subpixels 602G. The two G subpixels 602G are vertically shifted from the B subpixel 602B and the R subpixel 602R. As shown in Figure 7B, pixel 600B has a configuration similar to pixel 600A, except that the positions of R sub-pixel 602R and B sub-pixel 602B are swapped. As shown in Figure 6, pixels 600A and 600B are alternately arranged vertically and horizontally in first display area 422.

[0076] The second display area 424 includes pixels 600C. In the illustrated embodiment, the pixels 600C are configured similarly to the pixels 600A, each including one R subpixel 602R, two G subpixels 602G, and one B subpixel 602B. In the illustrated embodiment, the pixels 600A and 600B are adjacent to each other in the first display area 422, whereas the pixels 600C are spaced apart in the second display area 424. Thus, the pixel density of the second display area 424 is lower than that of the first display area 422. In the illustrated embodiment, the pixel density of the second display area 424 is one-quarter of the pixel density of the first display area 422.

[0077] 8 is a diagram illustrating an exemplary mapping of input pixels of an input image (shown in FIG. 5) to R, G, and B subpixels of display panel 420 (shown in FIG. 6), according to one or more embodiments. In the illustrated embodiment, the input pixels are defined such that the R and B subpixels are located at the corners of the corresponding input pixel, while the G subpixel is located at the center of the corresponding input pixel.

[0078] In subpixel rendering, the grayscale of each R subpixel of the display panel 420 is determined based on the R grayscale of one or more neighboring input pixels. Similarly, the grayscale of each G subpixel of the display panel 420 is determined based on the G grayscale of one or more neighboring input pixels, and the grayscale of each B subpixel of the display panel 420 is determined based on the B grayscale of one or more neighboring input pixels. Below, an exemplary determination (or calculation) of the grayscale of the R subpixel of the display panel 420 in subpixel rendering will first be described in detail.

[0079] FIG. 9 illustrates an exemplary R reference area defined for each red (R) subpixel of the display panel 420 in accordance with one or more embodiments. A reference area is an area that overlaps one or more neighboring pixels and is used to calculate the grayscale of a particular subpixel. The R reference area is the reference area for the particular R subpixel, the B reference area is the reference area for the particular B subpixel, and the G reference area is the reference area for the particular G subpixel. Determining the grayscale of each R subpixel of the display panel 420 includes defining an R reference area for each R subpixel of the display panel 420 and determining the grayscale of each R subpixel based at least in part on the R grayscale of an input pixel of the input image that at least partially overlaps the R reference area. The R reference areas are defined such that the location of each R reference area maps to the location of a corresponding R subpixel of the display panel 420. In one implementation, the R reference area may be defined such that the geometric center of each R reference area is located at the corresponding R subpixel of the display panel 420. The gray level of each R subpixel of the display panel 420 may be determined based at least in part on the R gray level of an input pixel that at least partially overlaps the R reference region defined for each R subpixel of the display panel 420.

[0080] In one or more embodiments, the R reference region corresponding to the R subpixels of the first display region 422 may be defined to be different from the R reference region corresponding to the R subpixels of the second display region 424. In one implementation, the definition of the R reference region corresponding to the R subpixels of the first display region 422 is indicated by a first setting 462 (shown in FIG. 4 ) stored in register circuit 460, and the definition of the R reference region corresponding to the R subpixels of the second display region 424 is indicated by a second setting 464 (also shown in FIG. 4 ) stored in register circuit 460. In this case, the first setting 462 and the second setting 464 may be defined such that the definition of the R reference region differs between the first display region 422 and the second display region 424. The definition of the R reference region for each of the first display region 422 and the second display region 424 may include the shape, area, one or more dimensions (e.g., width and height), or other spatial characteristics of the R reference region. Defining different R reference areas for the first display area 422 and the second display area 424 may mitigate image artifacts, distortions and / or color shifts in the display image obtained by subpixel rendering in view of the different pixel layouts of the first display area 422 and the second display area 424, and may effectively improve the quality of the display image.

[0081] In one implementation, the shape of the R reference region for the first display region 422 is different from the shape of the R reference region for the second display region 424. In the embodiment illustrated in Figure 9, the R reference region for the first display region 422 is defined as a rhombus (or diamond), while the R reference region for the second display region 424 is defined as a rectangle. Furthermore, the area of ​​the R reference region of the second display region 424, which has a lower pixel density than the first display region 422, is larger than the area of ​​the R reference region of the first display region 422.

[0082] 10 illustrates exemplary calculations performed in subpixel rendering to determine the grayscale of a subpixel 1002 of the first display region 422 based on an R reference region 1004 defined for the R subpixel 1002 of the first display region 422, according to one or more embodiments. In some embodiments, the grayscale of the R subpixel 1002 of the first display region 422 may be calculated by the first display region SPR circuit 445 (shown in FIG. 4) and incorporated into the first subpixel rendered data 448.

[0083] In one embodiment, the gray level of the R subpixel 1002 is calculated based at least in part on the R gray level of an input pixel P that at least partially overlaps the R reference region 1004. In the illustrated embodiment, the gray level of the R subpixel 1002 is calculated based at least in part on the R gray level of an input pixel P that at least partially overlaps the R reference region 1004. 00 , P 01 , P 10 and P 11 The calculation of the gray level of the R sub-pixel 1002 is further based on the R gray level of the input pixel P 00 , P 01 , P 10 and P 11 The overlapping ratio may be based on the percentage of overlap between the two.

[0084] In some embodiments, the gray level of the R subpixel 1002 is 00 , P 01 , P 10 and P 11 In one implementation, the gray level of the R subpixel 1002 may be calculated according to the following equation (1):

number

[0085] Input pixel P 00 , P 01 , P 10 and P 11 In an embodiment where the overlapping areas of the R reference region 1004 and the R sub-pixel 1002 are the same, the gray level of the R sub-pixel 1002 is 00 , P 01 , P 10 and P 11 In the embodiment shown in FIG. 00 , P 01 , P 10 and P 11 The ratios of the area of ​​the overlapping portion of each of the R subpixels 1002 to the area of ​​the R reference region 1004 are all 0.25. Therefore, the gradation of the R subpixel 1002 may be calculated as follows:

number

[0086] 11 illustrates exemplary calculations performed in subpixel rendering to determine the grayscale of the R subpixel 1102 in the second display region 424 of the display panel 420 based on an R reference region 1104 defined for the R subpixel 1102 in the second display region 424, in accordance with one or more embodiments. The grayscale of the R subpixel 1102 in the second display region 424 may be calculated in a manner similar to the grayscale of the R subpixel 1002 in the first display region 422 (shown in FIG. 10 ), except that the definition of the R reference region 1104 differs from the definition of the R reference region 1004. In some embodiments, the grayscale of the R subpixel 1102 in the second display region 424 may be calculated by the second display region SPR circuit 446 (shown in FIG. 4 ) and incorporated into the second subpixel rendered data 449.

[0087] In one embodiment, the gray level of the R subpixel 1102 is calculated based at least in part on the R gray levels of input pixels that at least partially overlap the R reference region 1104. In the illustrated embodiment, the gray level of the R subpixel 1102 is calculated based at least in part on the R gray levels of input pixels that at least partially overlap the R reference region 1104. 00 , P 01 , P 02 , P 03 , P 10 , P 11、 P 12 , P 13 The calculation of the gray level of the R sub-pixel 1102 is further based on the R gray level of the input pixel P 00 , P 01 , P 02 , P 03 , P 10 , P 11、 P 12 , P 13 The overlapping ratio may be based on the percentage of overlap between the two.

[0088] In some embodiments, the gray level of the R subpixel 1102 is 00 , P 01 , P 02 , P 03 , P 10 , P 11、 P 12 , P 13 In one implementation, the gray level of the R subpixel 1102 may be calculated according to the following equation (3):

number

[0089] Input pixel P 00 , P 01 , P 02 , P 03 , P 10 , P 11、 P 12 and P 13 In an embodiment where the overlapping areas of the R reference region 1104 of the input pixel P are the same, the gray level of the R subpixel 1102 is 00 , P 01 , P 02 , P 03 , P 10 , P 11、 P 12 and P 13 In the embodiment shown in FIG. 00 , P 01 , P 02 , P 03 , P 10 , P 11、 P 12 and P 13 The ratios of the area of ​​the overlapping portion of each of the R subpixels 1102 to the area of ​​the R reference region 1104 are all 0.125. Therefore, the gradation of the R subpixel 1102 may be calculated as follows.

number

[0090] In embodiments in which the shape of the R reference region differs between the first display region 422 and the second display region 424 (e.g., as illustrated in FIG. 9 ), at the boundary between the first display region 422 and the second display region 424, the R reference region defined for the first display region 422 may not align with the R reference region defined for the second display region 424. More specifically, the R reference region defined for an R subpixel in the second display region 424 may overlap one or more R reference regions defined for one or more R subpixels in the first display region 422. When the R reference region defined for an R subpixel in one of the first display region 422 and the second display region 424 overlaps one or more R reference regions defined for one or more R subpixels in the other of the first display region 422 and the second display region 424, such R subpixel may hereinafter be referred to as a border R subpixel.

[0091] 12 illustrates an exemplary R reference region 902 (also illustrated in FIG. 9 ) defined for a border R sub-pixel 1202 in the second display region 424 at the boundary between the first and second display regions 422 and 424, in accordance with one or more embodiments. In the illustrated embodiment, the R reference region 902 partially overlaps with R reference regions 1214, 1216, and 1218 defined for border R sub-pixels 1204, 1206, and 1208, respectively, in the first display region 422. When the R reference region 902 overlaps the R reference regions 1214, 1216, and 1218, the grayscale of the border R sub-pixel 1202 in the second display region 424 and the grayscale of the border R sub-pixels 1204, 1206, and 1208 in the first display region 422 are synchronized with the grayscale of the input pixel P where the R reference region 902 overlaps the R reference regions 1214, 1216, and 1218. 02 , P 03 , P 12 and P 13 This may result in redundant incorporation of information about the R gradation in the portion, which may cause image artifacts at the boundary between the first display area 422 and the second display area 424.

[0092] 13 illustrates another exemplary R reference region 904 (also illustrated in FIG. 9 ) defined for another border R sub-pixel 1302 in the second display region 424 at the boundary between the first and second display regions 422 and 424, in accordance with one or more embodiments. In the illustrated embodiment, the R reference region 904 partially overlaps with R reference regions 1314 and 1316 defined for border R sub-pixels 1304 and 1306, respectively, in the first display region 422. Similar to FIG. 12 , when the R reference region 904 overlaps the R reference regions 1314 and 1316, the grayscale of the border R sub-pixel 1302 in the second display region 424 and the grayscale of the border R sub-pixels 1304 and 1306 in the first display region 422 are adjusted to the grayscale of the input pixel P where the R reference region 904 overlaps the R reference regions 1314 and 1316. 00 , P 01 , P 02 and P 03 This may result in redundant incorporation of information about the R gradation in the portion, which may cause image artifacts at the boundary between the first display area 422 and the second display area 424.

[0093] One way to mitigate image artifacts may be to modify the shape of the R reference regions defined for boundary R sub-pixels located on the boundary between the first display area 422 and the second display area 424 so that the R reference regions defined for the boundary R sub-pixels do not overlap with any other R reference regions. However, this method may complicate the shape of the R reference regions defined for the boundary R sub-pixels and undesirably increase the amount of computation required for sub-pixel rendering.

[0094] In one or more embodiments, image artifacts at the boundary between the first display area 422 and the second display area 424 are mitigated by applying a boundary compensation factor to the grayscale of at least some of the boundary R subpixels. In some embodiments, the boundary compensation factor may be applied to the grayscale of the boundary R subpixels in the second display area 424. In other embodiments, the boundary compensation factor may be applied to the grayscale of the boundary R subpixels in both the first display area 422 and the second display area 424. In yet other embodiments, the boundary compensation factor may be applied to the grayscale of the boundary R subpixels in the first display area 422. The boundary compensation factor may be empirically predetermined and stored in the register circuit 460 as the boundary compensation factor 468 shown in FIG. 4 .

[0095] In one implementation, the gray levels of the boundary R subpixels in the second display region 424 may be determined by first determining the base gray levels of the boundary R subpixels as described above (e.g., according to equation (3) or (4) above) as the γ-th root of a weighted sum of the R gray levels of the corresponding input pixels raised to the γ-th power, and then applying a boundary compensation factor to the base gray level to determine the final gray levels of the boundary R subpixels. In some embodiments, the second display region SPR circuit 446 (shown in FIG. 4 ) may generate the second subpixel rendered data 449 such that the second subpixel rendered data 449 encompasses the base gray levels of the boundary R subpixels in the second display region 424. In such embodiments, the combining circuit 447 may be configured to apply the boundary compensation factor to the base gray levels of the boundary R subpixels in the second display region 424 to determine the final gray levels of the boundary R subpixels. The combining circuit 447 may also be configured to incorporate the final gray levels of the boundary R subpixels into the resulting subpixel rendered data 415.

[0096] For example, for the boundary R subpixel 1202 in the second display area 424 shown in FIG. 12, the basic grayscale of the boundary R subpixel 1202 is the same as that of the input pixel P 00 , P 01 , P 02, P 03 , P 10 , P 11 , P 12 and P 13 In one implementation, the base gray level of the boundary R subpixel 1202 is determined as follows:

number

number

[0097] The shape of the overlap of an R reference region defined for a border R subpixel in the second display region 424 with an R reference region defined for a border R subpixel in the first display region 422 may differ depending on the position of the border R subpixel. For example, with reference to Figures 12 and 13, the shape of the overlap of an R reference region 902 defined for a border R subpixel 1202 in the second display region 424 with R reference regions 1214, 1216, and 1218 defined for border R subpixels 1204, 1206, and 1208 in the first display region 422 differs from the shape of the overlap of an R reference region 904 defined for a border R subpixel 1302 in the second display region 424 with R reference regions 1314 and 1316 defined for border R subpixels 1304 and 1306 in the first display region 422.

[0098] In one or more embodiments, a border compensation coefficient is determined in association with the shape of the overlap between the first display region 422 and the second display region 424 to mitigate image artifacts between the first display region 422 and the second display region 424. More specifically, in some embodiments, the border compensation coefficient to be applied to the base gray level of a border R subpixel is determined based on the position of the border R subpixel. The border compensation coefficient to be applied to the base gray level of a border R subpixel may be selected from border compensation coefficients 468 stored in register circuit 460 (shown in FIG. 4 ) based on the position of the border R subpixel. Determining or selecting the border R subpixel based on the position of the border R subpixel may effectively mitigate image artifacts at the boundary between the first display region 422 and the second display region 424.

[0099] 9 illustrates a diamond-shaped R reference region for the R subpixels in the first display region 422 and a rectangular R reference region for the R subpixels in the second display region 424, the shapes of the R reference regions defined for the R subpixels in the first display region 422 and the second display region 424 may be variously modified depending on the implementation. The R reference region defined for the R subpixels in the first display region 422 may be, but is not limited to, a square, rectangle, parallelogram, hexagon, or any other regular polygon. The R reference region defined for the R subpixels in the second display region 424 may be, but is not limited to, a square, diamond, parallelogram, hexagon, or any other regular polygon.

[0100] FIG. 14A illustrates an exemplary R reference region defined for each R subpixel in the second display region 424, according to one or more embodiments. In the illustrated embodiment, the R reference region for the R subpixels in the second display region 424 is defined as a diamond. The R reference region is defined such that the position of each R reference region maps to the position of the corresponding R subpixel in the second display region 424. In one implementation, the R reference region may be defined such that the geometric center of each R reference region is located at the corresponding R subpixel in the second display region 424. The definition of the R reference region for the R subpixels in the second display region 424 may be indicated by a second setting 464 stored in the register circuit 460 (also illustrated in FIG. 4 ). The gray level of each R subpixel in the second display region 424 may be determined based at least in part on the R gray level of an input pixel that at least partially overlaps the R reference region defined for each R subpixel in the second display region 424.

[0101] FIG. 14B illustrates exemplary calculations performed in subpixel rendering to determine the grayscale of an R subpixel 1402 in the second display region 424 based on the R reference region 1404 defined as illustrated in FIG. 14A for the R subpixel 1402, according to one or more embodiments. In some embodiments, the grayscale of the R subpixel 1402 in the second display region 424 may be calculated by the second display region SPR circuit 446 (shown in FIG. 4) and incorporated into the second subpixel rendered data 449. In one embodiment, the grayscale of the R subpixel 1402 is calculated based at least in part on the R grayscale of input pixels that at least partially overlap with the R reference region 1404. In the illustrated embodiment, the grayscale of the R subpixel 1402 is calculated based at least in part on the R grayscale of twelve input pixels P that at least partially overlap with the R reference region 1404. 01 , P 02 , P 10 , P 11 , P 12 , P 13 , P 20 , P 21 , P 22 , P 23 , P 31 and P 32 The calculation of the gray level of the R sub-pixel 1402 is based at least in part on the R gray level of the input pixel P 01 , P 02 , P 10 , P 11 , P 12 , P 13 , P 20 , P 21 , P 22 , P 23 , P 31 and P 32 The overlapping ratio may further be based on the percentage of overlap between the two.

[0102] In some embodiments, the gray level of the R subpixel 1402 is 01 , P 02 , P 10 , P 11 , P 12 , P 13 , P 20 , P 21, P 22 , P 23 , P 31 and P 32 In one implementation, the gray level of the R subpixel 1402 may be calculated according to the following equation (7):

number

[0103] In the embodiment illustrated in FIG. 14B, the input pixel P 01 , P 02 , P 10 , P 13 , P 20 , P 23 , P 31 and P 32 The ratio of the area of ​​the overlapping portion of the R reference region 1404 to the total area of ​​the input pixel P 11 , P 12 , P 21 and P 22 The ratio of the area of ​​the overlapping portion to the total area of ​​the R reference region 1404 is 0.125. Therefore, the gradation of the R subpixel 1402 may be calculated as follows.

number

[0104] 15A illustrates an exemplary R reference region defined for each R subpixel in the second display region 424, according to another embodiment. In the illustrated embodiment, the R reference regions for the R subpixels in the second display region 424 are defined as hexagons. The R reference regions are defined such that the position of each R reference region maps to the position of the corresponding R subpixel in the second display region 424. In one implementation, the R reference regions may be defined such that the geometric center of each R reference region is located at the corresponding R subpixel in the second display region 424.

[0105] FIG. 15B illustrates exemplary calculations performed in subpixel rendering to determine the grayscale of an R subpixel 1502 in the second display region 424 based on the R reference region 1504 defined as illustrated in FIG. 15A for the R subpixel 1502, according to one or more embodiments. In some embodiments, the grayscale of the R subpixel 1502 in the second display region 424 may be calculated by the second display region SPR circuit 446 (shown in FIG. 4) and incorporated into the second subpixel rendered data 449. In one embodiment, the grayscale of the R subpixel 1502 is calculated based at least in part on the R grayscale of input pixels that at least partially overlap with the R reference region 1504. In the illustrated embodiment, the grayscale of the R subpixel 1502 is calculated based at least in part on the R grayscale of twelve input pixels P that at least partially overlap with the R reference region 1504. 01 , P 02 , P 10 , P 11 , P 12 , P 13 , P 20 , P 21 , P 22 , P 23 , P 31 and P 32 The calculation of the gray level of the R sub-pixel 1502 is based at least in part on the R gray level of the input pixel P 01 , P 02 , P 10 , P 11 , P 12 , P 13 , P 20, P 21 , P 22 , P 23 , P 31 and P 32 The overlapping ratio may further be based on the percentage of overlap between the two.

[0106] In some embodiments, the gray level of the R subpixel 1502 is 01 , P 02 , P 10 , P 11 , P 12 , P 13 , P 20 , P 21 , P 22 , P 23 , P 31 and P 32 In one implementation, the gray level of the R subpixel 1502 may be calculated according to the following equation (9):

number

[0107] In the embodiment illustrated in FIG. 15B, the input pixel P 01 , P 02 , P 31 and P 32 The ratio of the area of ​​the overlapping portion of the input pixel P 10 , P 13 , P 20 and P 23 The ratio of the area of ​​the overlapping portion of the input pixel P11 , P 12 , P 21 and P 22 The ratio of the area of ​​the overlapping portion to the total area of ​​the R reference region 1504 is 0.125. Therefore, the gradation of the R subpixel 1502 may be calculated as follows.

number

[0108] 16 illustrates exemplary blue (B) reference regions defined for each B subpixel of display panel 420, according to one or more embodiments. The grayscales of the B subpixels of display panel 420 may be determined (or calculated) in a similar manner to the grayscales of the R subpixels, except that the location of the B reference region defined for first display region 422 is different from the location of the R reference region defined for first display region 422, and the location of the B reference region defined for second display region 424 is different from the location of the R reference region defined for second display region 424. The definitions of the B reference regions corresponding to the B subpixels in first display region 422 may be indicated by first settings 462 (shown in FIG. 4 ) stored in register circuit 460, and the definitions of the B reference regions corresponding to the B subpixels in second display region 424 may be indicated by second settings 464 (also shown in FIG. 4 ) stored in register circuit 460.

[0109] Determining the grayscale of the B subpixel of the display panel 420 includes defining a B reference area for each B subpixel of the display panel 420 and determining the grayscale of each B subpixel based at least in part on the B grayscale of an input pixel of the input image that at least partially overlaps the B reference area. The B reference area is defined such that the location of each B reference area maps to the location of a corresponding B subpixel of the display panel 420. In one implementation, the B reference area may be defined such that the geometric center of each B reference area is located at the corresponding B subpixel of the display panel 420. The shape of the B reference area for the first display area 422 is different from the shape of the B reference area for the second display area 424. In the embodiment illustrated in FIG. 16 , the B reference area for the first display area 422 is defined as a rhombus (or diamond) shape, while the B reference area for the second display area 424 is defined as a rectangle.

[0110] The gray level of each B subpixel of the display panel 420 may be determined based at least in part on the B gray level of an input pixel that at least partially overlaps a B reference region defined for each B subpixel of the display panel 420. The gray levels of the B subpixels in the first display region 422 may be calculated in a similar manner as the R subpixels in the first display region 422 (e.g., according to equation (1) or (2)), while the gray levels of the B subpixels in the second display region 424 may be calculated in a similar manner as the R subpixels in the second display region 424 (e.g., according to equation (3) or (4)). In some embodiments, the grayscale of the B subpixel in the first display area 422 may be calculated by the first display area SPR circuit 445 (shown in FIG. 4) and incorporated into the first subpixel rendered data 448, while the grayscale of the B subpixel in the second display area 424 may be calculated by the second display area SPR circuit 446 (shown in FIG. 4) and incorporated into the second subpixel rendered data 449.

[0111] Additionally, the gradation of a border B subpixel may be calculated in a similar manner to that of a border R subpixel (e.g., according to equation (5) or (6)), where a border B subpixel is a B subpixel such that a B reference region defined for that B subpixel in one of the first display region 422 and the second display region 424 overlaps with one or more B reference regions defined for one or more B subpixels in the other of the first display region 422 and the second display region 424.

[0112] 17 illustrates an exemplary green (G) reference region defined for each G subpixel of the display panel 420, according to one or more embodiments. In the illustrated embodiment, each G subpixel of the display panel 420 corresponds to an input pixel of the input image and is located at the center of the corresponding input pixel of the input image. The definition of the G reference region corresponding to the G subpixel in the first display region 422 may be indicated by a first setting 462 (shown in FIG. 4 ) stored in the register circuit 460, and the definition of the G reference region corresponding to the G subpixel in the second display region 424 may be indicated by a second setting 464 (shown in FIG. 4 ) stored in the register circuit 460.

[0113] Determining the grayscale of the G subpixels of the display panel 420 includes defining a G reference area for each G subpixel of the display panel 420 and determining the grayscale of each G subpixel based at least in part on the G grayscale of one or more input pixels of the input image that at least partially overlap the G reference area. The G reference area is defined such that the position of each G reference area is mapped to the position of a corresponding G subpixel of the display panel 420. In one implementation, the G reference area may be defined such that the geometric center of each G reference area is located at the corresponding G subpixel of the display panel 420. The shape of the G reference area for the first display area 422 is different from the shape of the G reference area for the second display area 424.

[0114] 17 embodiment, the G reference region for each G subpixel in first display region 422 may be defined as the input pixel corresponding to each G subpixel. In such an embodiment, the gray level of each G subpixel in first display region 422 is determined as the G gray level of the corresponding input pixel. In some embodiments, the gray level of the G pixel in first display region 422 may be determined by first display region SPR circuit 445 (shown in FIG. 4) and incorporated into first subpixel rendered data 448.

[0115] Furthermore, the G reference region of each G subpixel in the second display region 424 is defined as a rectangle so as to overlap five input pixels. The grayscale of each G subpixel in the second display region 424 may be determined at least in part based on the G grayscales of the five input pixels that at least partially overlap the G reference region defined for each G subpixel in the second display region 424. The grayscale of the G subpixel in the second display region 424 may be calculated in the same manner as the R subpixel in the second display region 424 (for example, according to equation (3) or (4)).

[0116] FIG. 18 illustrates exemplary calculations performed in subpixel rendering to determine the grayscale of a G subpixel 1802 in the second display region 424 based on a G reference region 1804 defined for the G subpixel 1802 as illustrated in FIG. 17 , according to one or more embodiments. In some embodiments, the grayscale of the G subpixel 1802 in the second display region 424 may be calculated by the second display region SPR circuit 446 (illustrated in FIG. 4 ) and incorporated into the second subpixel rendered data 449. In one embodiment, the grayscale of the G subpixel 1802 is calculated based at least in part on the G grayscale of an input pixel that at least partially overlaps the G reference region 1804. In the illustrated embodiment, the grayscale of the G subpixel 1802 is calculated based at least in part on the G grayscale of five input pixels P that at least partially overlap the G reference region 1804. 00 , P 01 , P 02 , P 03 and P 04The calculation of the gray level of the G sub-pixel 1802 is further based on at least part of the G gray level of the input pixel P 00 , P 01 , P 02 , P 03 and P 04 The overlapping ratio may further be based on the percentage of overlap between the two.

[0117] In some embodiments, the gray level of the G subpixel 1802 is 00 , P 01 , P 02 , P 03 and P 04 In one implementation, the gray level of the G subpixel 1802 may be calculated according to the following equation (11):

number

[0118] In the embodiment illustrated in FIG. 18, the input pixel P 00 and P 04 The ratio of the area of ​​the overlapping portion of the input pixel P 01 , P 02 and P 03 The ratio of the area of ​​the overlapping portion of the G reference region 1804 to the area of ​​the G reference region 1804 is 0.25. Therefore, the gray level of the G subpixel 1802 may be calculated as follows:

number

[0119] A G reference region defined for a G subpixel in the second display region 424 may overlap one or more G reference regions defined for one or more G subpixels in the first display region 422. When a G reference region defined for a G subpixel in the second display region 424 overlaps one or more G reference regions defined for one or more G subpixels in the first display region 422, such G subpixels may be referred to hereinafter as border G subpixels.

[0120] 19 illustrates an exemplary G reference region 1702 (also illustrated in FIG. 17 ) defined for a border G sub-pixel 1902 in second display region 424 at the boundary between first display region 422 and second display region 424, in accordance with one or more embodiments. In the illustrated embodiment, G reference region 1702 is a G reference region defined for G sub-pixels 1904 and 1906 in first display region 422 (i.e., input pixel P 03 and P04 ) at least partially overlapping the G reference region 1702 defined for the G subpixels 1904 and 1906. If the G reference region 1702 overlaps the G reference region defined for the G subpixels 1904 and 1906, image artifacts may occur at the boundary between the first display region 422 and the second display region 424.

[0121] To mitigate image artifacts at the boundary between the first display area 422 and the second display area 424, in one or more embodiments, a border compensation factor is applied to the gray level of at least some of the border G sub-pixels in the second display area 424. The border compensation factor may be empirically determined in advance and stored in the register circuit 460 as part of the border compensation factor 468 as shown in FIG.

[0122] In one implementation, the gray levels of the boundary G subpixels in the second display region 424 may be determined by first determining the base gray levels of the boundary G subpixels as the γ-th root of a weighted sum of the γ-th powers of the G gray levels of the corresponding input pixels, as described above (e.g., according to equation (11) or (12) above), and then determining the final gray levels of the boundary G subpixels by applying a boundary compensation factor to the base gray level. In one implementation, the second display region SPR circuit 446 (shown in FIG. 4 ) may be configured to generate the second subpixel rendered data 449 such that the second subpixel rendered data 449 encompasses the base gray levels of the boundary G subpixels in the second display region 424, and the combining circuit 447 may be configured to apply the boundary compensation factor to the base gray levels of the boundary G subpixels in the second display region 424 to determine the final gray levels of the boundary G subpixels. The combining circuit 447 may be further configured to incorporate the final gray levels of the boundary G subpixels into the resulting subpixel rendered data 415.

[0123] For example, for the boundary G subpixel 1902 in the second display area 424 shown in FIG. 19, the basic grayscale of the boundary G subpixel 1902 is the same as that of the input pixel P 00 , P 01 , P02 , P 03 and P 04 In one implementation, the base gray level of the boundary G subpixel 1902 is determined as follows:

number

number

[0124] Method 2000 of Figure 20 illustrates example steps for driving a display panel (e.g., display panels 120, 270, 300, and 420 of Figures 1-4) according to one or more embodiments. Note that one or more of the steps illustrated in Figure 20 may be omitted, repeated, and / or performed in a different order than illustrated in Figure 20. Additionally, note that two or more steps may be performed simultaneously.

[0125] Method 2000 includes, at step 2002, receiving input image data corresponding to an input image (e.g., image data 112 in FIG. 1 , input image data 210 in FIG. 2 , and image data 412 in FIG. 4 ). Method 2000 further includes, at step 2004, generating first sub-pixel rendered data (e.g., low pixel density region output 223 in FIG. 2 and first sub-pixel rendered data 448 in FIG. 4 ) from a first portion of the input image data corresponding to a first display region of a display panel (e.g., first display region 122, 422 in FIGS. 1 and 4 and standard pixel density region 310 in FIG. 3 ) using a first setting (e.g., first setting 162 in FIG. 1 , setting 231 in FIG. 2 , and first setting 462 in FIG. 4 ). Generating the first sub-pixel rendered data may include applying sub-pixel rendering to the first portion of the input image data corresponding to the first display region.

[0126] Method 2000 further includes, in step 2006, generating second sub-pixel rendered data (e.g., standard pixel density region output 225 of FIG. 2 and second sub-pixel rendered data 449 of FIG. 4) from a second portion of the input image data corresponding to a second region of the display panel (e.g., second display region 124 and 424 of FIGS. 1 and 4, and low pixel density region 271 and 320 of FIGS. 2 and 3) using a second setting (e.g., second setting 164 of FIG. 1, setting 232 of FIG. 2, and second setting 464 of FIG. 4). Generating the second sub-pixel rendered data may include applying sub-pixel rendering to the second portion of the input image data corresponding to the second display region. The second setting is different from the first setting. The first setting is for a first pixel layout of the first display region, and the second setting is for a second pixel layout of the second display region, where the first pixel layout is different from the second pixel layout.

[0127] The method 2000 further includes updating a first display region of the display panel based at least in part on the first sub-pixel rendered data at step 2008. The method 2000 further includes updating a second display region of the display panel based at least in part on the second sub-pixel rendered data at step 2010.

[0128] While a number of embodiments have been described, those skilled in the art, having the benefit of this disclosure, will appreciate that they may devise other embodiments which do not depart from the scope thereof. Accordingly, the scope of the present invention should be limited solely by the appended claims.

Claims

1. receiving input image data corresponding to an input image; generating first sub-pixel rendered data from a first portion of the input image data corresponding to a first display area of ​​a display panel using a first setting; generating second sub-pixel rendered data from a second portion of the input image data corresponding to a second display area of ​​the display panel using a second setting different from the first setting; an image processing circuit configured as above; updating the first display area of ​​the display panel based at least in part on the first sub-pixel rendered data; a driver circuit configured to update the second display area of ​​the display panel based at least in part on the second sub-pixel rendered data; and Equipped with the first setting is for a first pixel layout in the first display area; the second setting is for a second pixel layout in the second display area; The first pixel layout is different from the second pixel layout. Display driver.

2. generating the first sub-pixel rendered data; defining a first reference area in the input image based at least in part on the first setting and a location of a first subpixel in the first display area of ​​the display panel; determining a first gray level of the first sub-pixel based at least in part on a gray level of a first pixel of the input image that at least partially overlaps the first reference region; Including, generating the second sub-pixel rendered data; defining a second reference area in the input image based at least in part on the second setting and on a location of a second subpixel in the second display area of ​​the display panel; determining a second gray level of the second sub-pixel based at least in part on a gray level of a second pixel of the input image that at least partially overlaps the second reference region; Contains 2. The display driver according to claim 1.

3. determining a second gray level of the second sub-pixel in the second display area of ​​the display panel includes determining an overlap ratio of the second reference area to the second pixel; Determining a second gray level for the second subpixel is further based on the ratio.

3. The display driver according to claim 2.

4. generating the first sub-pixel rendered data includes defining a first reference area in the input image based at least in part on the first setting and a location of a first sub-pixel in the first display area of ​​the display panel; generating the second sub-pixel rendered data; defining a third reference area in the input image based on the second setting and positions of border sub-pixels in the second display area of ​​the display panel such that the third reference area partially overlaps the first reference area; determining a base gray level of the boundary sub-pixel based at least in part on a gray level of a third pixel of the input image that at least partially overlaps the third reference region; determining a third gray level for the boundary sub-pixel by applying a boundary compensation factor to the base gray level; Contains 2. The display driver according to claim 1.

5. a display panel including a first display area having a first pixel layout and a second display area having a second pixel layout different from the first pixel layout; receiving input image data corresponding to an input image to be displayed on the display panel; generating first sub-pixel rendered data from a first portion of the input image data corresponding to the first display area using a first setting for the first pixel layout of the first display area; generating second sub-pixel rendered data from a second portion of the input image data corresponding to the second display area using a second setting for the second pixel layout of the second display area, the second setting being different from the first setting; updating the first display area of ​​the display panel based at least in part on the first sub-pixel rendered data; a display driver configured to update the second display area of ​​the display panel based at least in part on the second sub-pixel rendered data; and Equipped with Display device.

6. generating the first sub-pixel rendered data; defining a first reference area in the input image based at least in part on the first setting and a location of a first subpixel in the first display area of ​​the display panel; determining a first gray level of the first sub-pixel based at least in part on a gray level of a first pixel of the input image that at least partially overlaps the first reference region; Including, generating the second sub-pixel rendered data; defining a second reference area in the input image based at least in part on the second setting and on a location of a second subpixel in the second display area of ​​the display panel; determining a second gray level of the second sub-pixel based at least in part on a gray level of a second pixel of the input image that at least partially overlaps the second reference region; Contains The display device according to claim 5 .

7. generating the first sub-pixel rendered data includes defining a first reference area in the input image based at least in part on the first setting and a location of a first sub-pixel in the first display area of ​​the display panel; generating the second sub-pixel rendered data; defining a third reference region in the input image based at least in part on the second setting and on locations of border subpixels in the second display region of the display panel, such that the third reference region partially overlaps the first reference region; determining a base gray level of the boundary sub-pixel based at least in part on a gray level of a third pixel of the input image that at least partially overlaps the third reference region; determining a third gray level for the boundary sub-pixel by applying a boundary compensation factor to the base gray level; Contains The display device according to claim 5 .

8. receiving input image data corresponding to an input image; generating first sub-pixel rendered data from a first portion of the input image data corresponding to a first display area of ​​a display panel using a first setting; generating second sub-pixel rendered data from a second portion of the input image data corresponding to a second display area of ​​the display panel using a second setting different from the first setting; updating the first display area of ​​the display panel based at least in part on the first sub-pixel rendered data; updating the second display area of ​​the display panel based at least in part on the second sub-pixel rendered data; Including, the first setting is for a first pixel layout in the first display area; the second setting is for a second pixel layout in the second display area; The first pixel layout is different from the second pixel layout. method.

9. generating the first sub-pixel rendered data; defining a first reference area in the input image based at least in part on the first setting and a location of a first subpixel in the first display area of ​​the display panel; determining a first gray level of the first sub-pixel based at least in part on a gray level of a first pixel of the input image that at least partially overlaps the first reference region; Including, generating the second sub-pixel rendered data; defining a second reference area in the input image based at least in part on the second setting and on a location of a second subpixel in the second display area of ​​the display panel; determining a second gray level of the second sub-pixel based at least in part on a gray level of a second pixel of the input image that at least partially overlaps the second reference region; Contains The method of claim 8.

10. generating the first sub-pixel rendered data includes defining a first reference area in the input image based at least in part on the first setting and a location of a first sub-pixel in the first display area of ​​the display panel; generating the second sub-pixel rendered data; defining a third reference region in the input image based at least in part on the second setting and on locations of border subpixels in the second display region of the display panel, such that the third reference region partially overlaps the first reference region; determining a base gray level of the boundary sub-pixel based at least in part on a gray level of a third pixel of the input image that at least partially overlaps the third reference region; determining a third gray level for the boundary sub-pixel by applying a boundary compensation factor to the base gray level; Contains The method of claim 8.

Images