PATENT DOCUMENT

Publication Number: US-10657912-B2
Application Number: US-201916368394-A
Country: US
Kind Code: B2

Title: Display with pixel dimming for curved edges

Abstract:
A display may have curved edges such as rounded corners. Pixels in the display may be controlled so that the active area of the display has the desired curved edge shape. In order to maximize the apparent smoothness of the curved edge, the display may include circuitry that dims some of the pixels based on their location relative to a spline for the curved edge. The display circuitry may include a multiplication circuit that receives image data as a first input and dimming factors from a gain table as a second input. The image data may include a brightness level for each pixel in the array of pixels. The multiplication circuit may multiply the brightness level for each pixel by its respective dimming factor. This modified image data may then be supplied to the imaging pixels using display driver circuitry.

Claims:
What is claimed is: 
     
       1. An electronic device comprising:
 a display that includes a plurality of pixels that form an active area of the display, wherein the active area of the display has at least one rounded corner that follows an outline of the active area; and 
 control circuitry configured to provide image data to the display, wherein the image data comprises a brightness value for each pixel, wherein the control circuitry comprises circuitry is configured to modify the image data based on at least one dimming factor, wherein each pixel has a respective dimming factor, wherein the dimming factor associated with each pixel is associated with at least a location of that pixel relative to the outline, and wherein the dimming factor associated with pixels positioned outside of the outline at least is associated with a contour of the outline at a position on the outline that is associated with the location of that pixel. 
 
     
     
       2. The electronic device defined in  claim 1 , wherein the circuitry configured to modify the image data comprises a multiplication circuit configured to multiply the brightness value for each pixel by the dimming factor associated with that pixel. 
     
     
       3. The electronic device defined in  claim 2 , wherein the control circuitry includes display driver circuitry that provides the modified image data to the plurality of pixels, and wherein the plurality of pixels displays an image based on the modified image data. 
     
     
       4. The electronic device defined in  claim 1 , wherein the dimming factor associated with pixels having a center outside of the outline is at least associated with a distance of that pixel to the outline. 
     
     
       5. The electronic device defined in  claim 4 , wherein the dimming factor for the pixels having centers outside of the outline decreases as the distance of the pixel to the outline increases. 
     
     
       6. The electronic device defined in  claim 5 , wherein the distance of each pixel to the outline is measured as a distance from the center of that pixel to the outline, wherein the dimming factor for each pixel that is greater than one pixel width outside of the outline is 0, and wherein the display has four sides with four rounded corners. 
     
     
       7. The electronic device defined in  claim 1 , wherein the dimming factor associated with pixels having a center outside of the outline at least is associated with a normalized distance of that pixel to the outline. 
     
     
       8. Display circuitry for a display having an active area with a curved edge that follows an outline of the active area, the display circuitry comprising:
 a plurality of pixels configured to display images; 
 a multiplication circuit that is configured to receive image data, wherein the image data includes a brightness value for each pixel of the plurality of pixels, wherein the multiplication circuit is configured at least to multiply the brightness value for each pixel by a dimming factor associated with that pixel to obtain modified image data, and wherein the dimming factor for each pixel having a center outside of the outline at least is associated with a position of that pixel relative to the outline; and 
 display driver circuitry configured to provide the modified image data to the plurality of pixels. 
 
     
     
       9. The display circuitry defined in  claim 8 , further comprising a gain table that includes the dimming factor for each pixel, wherein the dimming factor for each of the pixels having centers outside of the outline decreases as a distance between that pixel and the outline increases. 
     
     
       10. The display circuitry defined in  claim 8 , wherein the dimming factor for each of the pixels having centers that are greater than one pixel width outside of the outline is 0. 
     
     
       11. The display circuitry defined in  claim 8 , wherein the dimming factor for each of the pixels having centers outside of the outline at least is associated with a normalized distance between that pixel and the outline. 
     
     
       12. The display circuitry defined in  claim 11 , wherein the dimming factor for each of the pixels having centers outside of the outline is also at least associated with a contour of the outline associated with a location of that pixel. 
     
     
       13. An electronic device having a display, the electronic device comprising:
 a plurality of pixels that form an active area of the display, wherein the active area has at least one rounded corner along at least a portion of an edge of the active area; and 
 control circuitry that is configured to multiply a brightness value for each pixel by a respective dimming factor to mitigate jaggedness of the at least one rounded corner, wherein the control circuitry includes display driver circuitry that provides the modified brightness values to the plurality of pixels, wherein a spline defines the optimal outline for the active area, and wherein the dimming factor associated with each pixel having a center outside of the spline at least is associated with a location of that pixel. 
 
     
     
       14. The electronic device defined in  claim 13 , wherein the dimming factor associated with each pixel having a center inside of the spline is 1 and wherein the dimming factor associated with each pixel having a center outside of the spline at least is associated with a contour of the spline at a position on the spline that is associated with a location of that pixel. 
     
     
       15. The electronic device defined in  claim 13 , wherein the dimming factor associated with each pixel having a center inside of the spline is 1 and wherein the dimming factor associated with each pixel having a center outside of the spline at least is a function of a curvature factor that is associated with a contour of the spline at a position on the spline that is associated with a location of that pixel. 
     
     
       16. The electronic device defined in  claim 13 , wherein the dimming factor associated with each pixel having a center inside of the spline is 1 and wherein the dimming factor associated with each pixel having a center outside of the spline at least is a function of a distance of the center of that pixel to the spline. 
     
     
       17. The electronic device defined in  claim 13 , wherein pixels in a center of the active area and pixels in the at least one rounded corner have the same sub-pixel layout. 
     
     
       18. The electronic device defined in  claim 13 , wherein every pixel of the plurality of pixels is rectangular.

Description:
This application is a continuation of U.S. non-provisional patent application Ser. No. 15/767,637, filed on Apr. 11, 2018, which is a 371 of International Patent Application PCT/US2017/042437, filed on Jul. 17, 2017, which claims priority to U.S. provisional patent application No. 62/371,165, filed on Aug. 4, 2016, which are hereby incorporated by reference herein in their entireties. 
    
    
     BACKGROUND 
     This relates generally to electronic devices, and, more particularly, to electronic devices with displays. 
     Electronic devices such as cellular telephones, computers, and wristwatch devices often include displays. For example, an electronic device may have an organic light-emitting diode display based on organic-light-emitting diode pixels or a liquid crystal display based on liquid crystal pixels. Conventional displays may have a rectangular shape with an outline that has right angles in each of its four corners. However, this type of shape may not match the desired aesthetic for the electronic device. 
     It would therefore be desirable to be able to provide improved displays for electronic devices. 
     SUMMARY 
     A display may have an array of pixels. The display may be a liquid crystal display, may be an organic light-emitting diode display, or may be a display of other types. 
     In a display, the array of pixels may form an active area of the display. It may sometimes be desirable for the active area of the display to have curved edges. For example, the active area may have four sides that are connected by four rounded corners. Each rounded corner may be defined by a spline. 
     Pixels in the pixel array may be controlled so that the active area of the display has the desired curved edge shape. In one scheme, pixels that are within the spline will be turned on while pixels that are not within the spline will be turned off. However, this type of arrangement may result in the curved edge appearing jagged to the user. In order to maximize the apparent smoothness of the curved edge, the display may include circuitry that dims some of the pixels without turning them entirely off. 
     The display circuitry may include a multiplication circuit that receives image data as a first input and dimming factors from a gain table as a second input. The image data may include a brightness level for each pixel in the array of pixels. The gain table may include a dimming factor for each pixel in the array of pixels. The multiplication circuit may multiply the brightness level for each pixel by its respective dimming factor. This modified image data may then be supplied to the imaging pixels using display driver circuitry. 
     The dimming factor for each pixel may be a function of the distance of the pixel from the spline. The dimming factor for each pixel may also be a function of the linear velocity associated with the location of the pixel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of an illustrative electronic device having a display in accordance with an embodiment. 
         FIG. 2  is a top view of an illustrative array of pixels for a display with rounded corners in accordance with an embodiment. 
         FIG. 3  is a top view of an illustrative spline for a display with rounded corners in accordance with an embodiment. 
         FIG. 4  is a zoomed-in image of the illustrative spline of  FIG. 3  showing how the display may have jagged edges in accordance with an embodiment. 
         FIG. 5  is a schematic diagram of an illustrative display that modifies image data based on dimming factors in accordance with an embodiment. 
         FIG. 6  is a flowchart of illustrative steps involved in operation of the display shown in  FIG. 5  in accordance with an embodiment. 
         FIG. 7  is a top view of an illustrative display with a spline showing how the distance of sub-pixels from the spline may be determined in accordance with an embodiment. 
         FIG. 8  is a zoomed-in image of  FIG. 7  further demonstration how the distance of sub-pixels from the spline may be determined in accordance with an embodiment. 
         FIG. 9  is a top view of an illustrative display with a spline showing how the linear velocity associated with a given sub-pixel may be determined in accordance with an embodiment. 
         FIG. 10  is a flowchart of illustrative steps involved in determining dimming factors for sub-pixels based on the distance of the sub-pixel from the spline in accordance with an embodiment. 
         FIG. 11  is a flowchart of illustrative steps involved in determining dimming factors for sub-pixels based on the distance of the sub-pixel from the spline and the linear velocity associated with the sub-pixel in accordance with an embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     An illustrative electronic device of the type that may be provided with a display is shown in  FIG. 1 . Electronic device  10  may be a computing device such as a laptop computer, a computer monitor containing an embedded computer, a tablet computer, a cellular telephone, a media player, or other handheld or portable electronic device, a smaller device such as a wrist-watch device, a pendant device, a headphone or earpiece device, a device embedded in eyeglasses or other equipment worn on a user&#39;s head, or other wearable or miniature device, a display, a computer display that contains an embedded computer, a computer display that does not contain an embedded computer, a gaming device, a navigation device, an embedded system such as a system in which electronic equipment with a display is mounted in a kiosk or automobile, or other electronic equipment. 
     As shown in  FIG. 1 , electronic device  10  may have control circuitry  16 . Control circuitry  16  may include storage and processing circuitry for supporting the operation of device  10 . The storage and processing circuitry may include storage such as hard disk drive storage, nonvolatile memory (e.g., flash memory or other electrically-programmable-read-only memory configured to form a solid state drive), volatile memory (e.g., static or dynamic random-access memory), etc. Processing circuitry in control circuitry  16  may be used to control the operation of device  10 . The processing circuitry may be based on one or more microprocessors, microcontrollers, digital signal processors, baseband processors, power management units, audio chips, application specific integrated circuits, etc. 
     Input-output circuitry in device  10  such as input-output devices  12  may be used to allow data to be supplied to device  10  and to allow data to be provided from device  10  to external devices. Input-output devices  12  may include buttons, joysticks, scrolling wheels, touch pads, key pads, keyboards, microphones, speakers, tone generators, vibrators, cameras, sensors, light-emitting diodes and other status indicators, data ports, etc. A user can control the operation of device  10  by supplying commands through input-output devices  12  and may receive status information and other output from device  10  using the output resources of input-output devices  12 . 
     Input-output devices  12  may include one or more displays such as display  14 . Display  14  may be a touch screen display that includes a touch sensor for gathering touch input from a user or display  14  may be insensitive to touch. A touch sensor for display  14  may be based on an array of capacitive touch sensor electrodes, acoustic touch sensor structures, resistive touch components, force-based touch sensor structures, a light-based touch sensor, or other suitable touch sensor arrangements. A touch sensor for display  14  may be formed from electrodes formed on a common display substrate with the pixels of display  14  or may be formed from a separate touch sensor panel that overlaps the pixels of display  14 . If desired, display  14  may be insensitive to touch (i.e., the touch sensor may be omitted). 
     Control circuitry  16  may be used to run software on device  10  such as operating system code and applications. During operation of device  10 , the software running on control circuitry  16  may display images on display  14 . 
       FIG. 2  shows an illustrative display with an active area AA that has four sides and four curved (rounded) corners. The active area of display  14  may have a center  36 . Other display shapes with one or more curved edges may be used in forming display  14 , if desired. Display  14  may have an array of pixels  32  for displaying images for a user such as pixel array  34 . Pixels  32  in array  34  may be arranged in rows and columns. The edges of array  34  may be curved (i.e., some rows of pixels  32  and/or some columns of pixels  32  in array  34  may have a different length). There may be any suitable number of rows and columns in array  34  (e.g., ten or more, one hundred or more, or one thousand or more, etc.). Display  14  may include pixels  32  of different colors. As an example, display  14  may include red pixels, green pixels, and blue pixels. In some cases, a single pixel may be said to include a red sub-pixel, a blue sub-pixel, and a green sub-pixel. However, these sub-pixels may sometimes be referred to as pixels themselves (i.e., a red pixel, a blue pixel, a green pixel, etc.) If desired, a backlight unit may provide backlight illumination for display  14 . 
     Display driver circuitry may be used to control the operation of pixels  32 . The display driver circuitry may be formed from integrated circuits, thin-film transistor circuits, or other suitable circuitry formed in the inactive area of the display. The display driver circuitry may be able to communicate with system control circuitry (i.e., control circuitry  16 ). During operation, the control circuitry may supply circuitry such as a display driver integrated circuit with image data for images to be displayed on display  14 . To display the images on pixels  32 , the display driver circuitry may supply corresponding image data to data lines D and assert gate line signals on gate lines G in sequence, starting with the gate line signal G in the first row of pixels  32  in array  34 . As each gate line is asserted, data from data lines D may be loaded into a corresponding row of pixels. In this way, the control circuitry may provide pixels  32  with signals that direct pixels  32  to display a desired image on display  14 . Horizontal control lines G (sometimes referred to as gate lines, scan lines, emission control lines, etc.) may run horizontally through display  14  and be associated with respective rows of pixels  32 , while data lines D may run vertically through display  14  and be associated with respective columns of pixels  32 . 
     As shown in  FIG. 2 , the active area of a display may sometimes be provided with curved edges. This type of shape may maximize the size of the active area of the display. However, ensuring that the curved edges of the display appear smooth and aesthetically pleasing may be challenging. An enlarged portion of the display ( 14 - 1 ) from  FIG. 2  is shown in  FIG. 3  to illustrate some of these challenges. 
       FIG. 3  shows a plurality of pixels  32  that are a part of pixel array  34 . In order for display  14  to have rounded corners as shown in  FIG. 2 , the pixels may follow a spline  42  (sometimes referred to herein as a spline curve or a spline edge). The spline may be the optimal outline for the active area of the display. Ideally, uniform light would be emitted at all points inside the spline and no light would be emitted at points outside of the spline. This would ensure that the active area displays a curve that appears smooth to a user of the electronic device. However, because individual pixels in the display may be discernable to a user, selectively enabling pixels to try to follow the spline may result in a curved edge that appears jagged to the user along the spline. The jagged edges that may result are depicted in  FIG. 4 , which shows a zoomed-in version of portion  14 - 2  of the spline and active area. 
     First, it should be noted that each pixel  32  may contain three sub-pixels  32 - 1 ,  32 - 2 , and  32 - 3 . Sub-pixel  32 - 1  may be a red sub-pixel, sub-pixel  32 - 2  may be a green sub-pixel, and sub-pixel  32 - 3  may be a blue sub-pixel. Each pixel  32  may have red, green, and blue sub-pixels  32 - 1 ,  32 - 2 , and  32 - 3  arranged as shown in  FIG. 4 . Sometimes the sub-pixels may be referred to as pixels. In each pixel, the red sub-pixel may be positioned on top of the green sub-pixel, and the blue sub-pixel may be positioned to the right of the red and green sub-pixels. This example of a pixel layout is merely illustrative, and any desired pixels or sub-pixels may be used in display  14 . 
       FIG. 4  shows a pixel scheme for forming the spline edge where each pixel is controlled individually to be either on or off. As shown, pixels that are within the spline edge are turned on (i.e., these pixels are capable of emitting light), while pixels that are not within the spline edge are turned off (i.e., these pixels are not capable of emitting light and will be dark). Illustrative pixel groups  44  show which pixels  32  may be considered within the spline edge and turned on. The remaining pixels will remain off. As is visible in  FIG. 4  based on the shape of pixel groups  44 , this type of pixel arrangement may result in the display having jagged edges. 
     In order to prevent jaggedness in the edges of the display, the display pixel data may be modified by dimming factors.  FIG. 5  shows a schematic diagram of illustrative circuitry that may be used in implementing display  14  of device  10 . During operation of electronic device  10 , control circuitry in the device may supply image data  26  for images to be displayed on display  14 . Ultimately, the image data may be delivered to display driver circuitry  50 , which may supply the image data to data lines D of the display. Display driver circuitry  50  may also include gate driver circuitry which is used to assert gate line signals on gate lines G of display  14 . The display driver circuitry may be used to provide the image data to the pixels in pixel array  34 . 
     Before being provided to display driver circuitry  50 , the image data may be multiplied by dimming factors from gain table  28  in multiplication circuit  30  (sometimes referred to herein as a gain circuit). Each frame of image data  26  may include a representative brightness value for each pixel  32  in pixel array  34 . Gain table  28  may include a dimming factor for each pixel (or sub-pixel)  32  in pixel array  34 . The dimming factor may be associated with the location of the pixel relative to the spline edge of the display. Each pixel that is within the spline edge of the display may have a dimming factor of 1 (meaning that the brightness level for that pixel will not be modified). Pixels that are outside the spline edge of the display may have a dimming factor between 0 and 1. When the brightness level for a pixel is multiplied by a dimming factor less than 1 in gain circuit  30 , the brightness of that particular pixel will be reduced (i.e. dimmed). Dimming the pixels outside the spline edge of the display may enable the edge of the display to appear smoother to the user. 
     After image data  26  is multiplied by the dimming factors from gain table  28 , the modified image data may be provided to display driver circuitry  50 . Display driver circuitry  50  will then provide the modified image data to the pixels in pixel array  34 . Pixel array may then display the desired image with curved edges that do not appear jagged to the user. 
     Multiplication circuit  30 , gain table  28 , display driver circuitry  50 , and pixel array  34  as shown in  FIG. 5  may sometimes be collectively referred to as display circuitry. Alternatively, pixel array  34  may sometimes be referred to as a display while multiplication circuit  30 , gain table  28 , and display driver circuitry  50  may sometimes collectively be referred to as control circuitry. 
     A flowchart showing illustrative method steps for modifying image data to achieve a smoother display edge is shown in  FIG. 6 . As shown, at step  102  image data (i.e., image data  26 ) may be provided. Once the image data is provided, the image data may be multiplied by dimming factors found in a gain table (i.e., gain table  28 ) at step  104 . Each pixel may be multiplied by a dimming factor between 0 and 1 that is associated with the location of that particular pixel. After the image data has been modified, the modified image data may be provided to display driver circuitry (i.e., display driver circuitry  50 ) at step  106 . Finally, at step  108  an image may be displayed using the pixels in the pixel array based on the modified image data. Display driver circuitry  50  may supply the modified image data to pixels  32  to display the image. 
     The method steps shown in  FIG. 6  may be applied to any type of display. Fundamentally, the method involves adjusting the brightness levels of pixels to achieve a smooth curve. This type of method may be applied to light-emitting diode (LED) displays, organic light-emitting diode (OLED) displays, liquid crystal (LC) displays, liquid crystal on silicon (LCOS) displays, etc. The displays may be reflective displays, transmissive displays, transreflective displays, or any other desired type of display. In general, any type of display may be used. 
     The dimming factors used in gain table  28  may be determined in a variety of ways. In a first illustrative embodiment, a dimming factor may be associated with each sub-pixel in the pixel array (i.e., each pixel may have corresponding sub-pixels  32 - 1 ,  32 - 2 , and  32 - 3  that all have respective dimming factors). The dimming factor may be based on the distance of the sub-pixel from the spline edge.  FIG. 7  illustrates how distance of the sub-pixel from the spline edge may be used to determine a dimming factor for the sub-pixel. For simplicity,  FIG. 7  shows just a single pixel, but it is understood that this type of dimming factor may be applied to any sub-pixel in the array. Additionally, it should be noted that  FIG. 7  is not necessarily to scale and is merely illustrating the described concepts. 
       FIG. 7  shows spline edge  42  separated from center  36  of the display active area. Illustrative sub-pixels  32 - 1 ,  32 - 2 , and  32 - 3  are shown in  FIG. 7 . Each sub-pixel may have a respective center. Center  46 - 1  may be the center of red sub-pixel  32 - 1 , center  46 - 2  may be the center of green sub-pixel  32 - 2 , and center  46 - 3  may be the center of blue sub-pixel  32 - 3 . The dimming factor for any sub-pixel with a center within spline edge  42  may be 1. This means that any sub-pixel with a center within spline edge  42  will not be dimmed. Sub-pixel  32 - 2  is an example of pixel with a center within the spline edge. As shown, sub-pixel  32 - 2 &#39;s center  46 - 2  is positioned within the spline edge. Accordingly, the dimming factor for sub-pixel  32 - 2  in  FIG. 7  is 1. 
     Sub-pixels that have a center outside of the spline edge may have a dimming factor less than 1. If a sub-pixel has a center outside of the spline edge, the dimming factor may be determined by the distance between the center of the sub-pixel and the spline edge. For example, sub-pixel  32 - 1  has a center  46 - 1  that is positioned outside of the spline edge. In order to determine the distance between center  46 - 1  and spline  42 , a point on spline  42  must be selected as the relevant point for the measurement. This point is determined by drawing a line between the center of the sub-pixel and the center of the active area. This line is represented by line  48  in  FIG. 7 . As shown, line  48  is coupled between the center of the active area and the center of sub-pixel  32 - 1 . A similar line may be used for sub-pixel  46 - 3 . As shown, line  52  connects center  36  of the active area to center  46 - 3  of pixel  32 - 3 . A zoomed-in version of the pixel shown in  FIG. 7  is shown in  FIG. 8 . 
     As shown in  FIG. 8 , point  54  may be the point on spline  42  directly between the center of the active area and the center of sub-pixel  32 - 1 . The distance between point  54  and center  46 - 1  may be considered the distance  58  between sub-pixel  32 - 1  and spline  42 . Similarly, point  56  may be the point on spline  42  directly between center  36  of the active area and center  46 - 3  of sub-pixel  32 - 3 . The distance between point  56  and center  46 - 3  may be considered the distance  60  between sub-pixel  32 - 3  and spline  42 . 
     In order to use the distance between the sub-pixel and the spline to calculate a dimming factor, the distance may be normalized by dividing the distance by the size of a pixel. For example, each pixel in the array may have a width  62 , as shown in  FIG. 8 . The width or any other desired dimension of the pixel may be taken to represent the size of the pixel. Using pixel width as a representative of pixel size (as in this example) is merely illustrative and any other desired pixel dimension (i.e., length) may be used to represent pixel size. Normalized distance (d) may be determined by dividing the distance between the sub-pixel and the spline by the size of the pixel (i.e., d=distance/pixel size). The dimming factor (DF) for each sub-pixel outside of the spline may then be determined by the following equation: DF=1−d. In this equation, ‘d’ is the normalized distance of the sub-pixel from the spline as previously described. Using this equation, the dimming factor will progress from 1 to 0 as the sub-pixels get further away from the spline. For example, a sub-pixel that is very close the spline may have a dimming factor of 0.95 (meaning only a 5% reduction in brightness). In contrast, a sub-pixel that is further away from the spline may have a dimming factor of 0.05 (meaning a 95% reduction in brightness). The minimum dimming factor may be 0. This means that sub-pixels that have a distance from the spline greater than 1 pixel width may always be turned off. 
     Modifying the image data based on the distance between sub-pixels and the spline may improve the apparent smoothness of the edges of the display. However, further improvements may be made by adjusting the dimming factor not only based on distance between the sub-pixel and the spline, but also the linear velocity of the spline. Information on obtaining the linear velocity of the spline is shown in  FIG. 9 . Linear velocity may depend on the contour of the spline at a location on the spline associated with the location of the pixel of interest. For simplicity,  FIG. 9  shows just a single pixel, but it is understood that this type of dimming factor may be applied to any sub-pixel in the array. Additionally, it should be noted that  FIG. 9  is not necessarily to scale and is merely illustrating the described concepts. 
       FIG. 9  shows spline edge  42  separated from center  36  of the display active area. Illustrative sub-pixels  32 - 1 ,  32 - 2 , and  32 - 3  are shown in  FIG. 9 . Each sub-pixel may have a respective center as described in connection with  FIG. 7 . Center  46 - 1  may be the center of red sub-pixel  32 - 1 . Each sub-pixel may have a corresponding linear velocity function (LVF) determined by the linear velocity (LV) associated with the center of the particular sub-pixel. Sub-pixel  32 - 1  will now be examined as an example of obtaining linear velocity. As described in connection with  FIGS. 7 and 8 , a line  48  may be drawn from the center  36  of the active area to the center of sub-pixel  32 - 1 . This line may intersect spline  42  at point  54  as shown. Point  54  may be the point on the spline directly between the center of the active area and the center of sub-pixel  32 - 1 . The distance between center  36  and point  54  along line  48  may be characterized by distance  64 . This distance may sometimes be referred to as r1. Next, another line  68  may be drawn that is separated from line  48  by an angle  66  (θ). The angle may be approximately 1° or any other desired angle (i.e., 0.5°, 0.1°, less than 0.1°, greater than 0.1°, etc.). Line  68  may have a point of intersection with spline  42  (point  72 ). Point  72  may be the point on the spline directly between the center of the active area and the center of sub-pixel  32 - 3 . The distance between center  36  and point  72  along line  68  may be characterized by distance  70 . This distance may sometimes be referred to as r2. The linear velocity (LV) may subsequently be determined using the following equation: LV=(r2−r1)/θ. 
     The linear velocity may be used to determine a linear velocity function (LVF). The linear velocity function may simply be the linear velocity adjusted by some constants to optimize smoothness in the display. The following equation may be used to determine the linear velocity function: LVF=(LV/a)+b. The constants ‘a’ and ‘b’ may be selected to achieve maximum smoothness of the display edges. Finally, the dimming factor for each pixel may be determined using a similar formula as previously described above. However, instead of determining the dimming factor solely as a function distance (as previously described), the dimming factor (DF) may be determined as a function of distance and linear velocity using the following formula: DF=1−(d/LVF). In this formula, ‘d’ is the normalized distance of the sub-pixel from the spline as previously described and LVF is the linear velocity function as previously described. 
     In  FIGS. 7-9 , the center of the active area ( 36 ) is used as a reference point for determining dimming factors for display pixels. However, this example is merely illustrative. Any desired location on the display panel may be used as a reference point in determining the linear velocities and dimming factors of pixels. 
       FIGS. 10 and 11  show illustrative methods for determining dimming factors for sub-pixels in the display.  FIG. 10  shows a method of determining the dimming factor as a function of the distance between the sub-pixel and the spline. At step  202 , the distance between the sub-pixel and the spline may be determined, as described in connection with  FIGS. 7 and 8 . The distance may then be normalized at step  204 . The distance may be normalized by dividing the distance between the sub-pixel and the spline by pixel size. The pixel size may be any representative dimension of a pixel. For example, the width of the pixel, the height of the pixel, or the diagonal dimension of the pixel may be used. Once normalized, the dimming factor may be determined based on the normalized distance at step  206 . 
       FIG. 11  shows a method of determining the dimming factor as a function of the distance between the sub-pixel and the spline and as a function of the linear velocity associated with the sub-pixel. As shown, at step  302  the distance between the sub-pixel and the spline may be determined, as described in connection with  FIGS. 7 and 8 . The distance may then be normalized at step  304 . The distance may be normalized by dividing the distance between the sub-pixel and the spline by pixel size. The pixel size may be any representative dimension of a pixel. For example, the width of the pixel, the height of the pixel, or the diagonal dimension of the pixel may be used. At step  306 , the linear velocity associated with the sub-pixel may be determined, as described in connection with  FIG. 9 . 
     It should be noted that instead of precisely calculating the linear velocity for each and every sub-pixel, the linear velocity may instead be determined using a look-up table and interpolation. The point between each sub-pixel center and the active area center on the spline has an angle relative to the active area center (i.e., 0°, 10°, 40°, 90°, etc.). The linear velocity for certain angles (i.e., every whole degree) may be stored in a look-up table. Take an example where a given sub-pixel has a representative angle of 22.3°. The linear velocities associated with 22° and 23° may be obtained from the look-up table, and interpolation may be performed to approximate a linear velocity for 22.3°. Any desired type of interpolation may be performed (i.e., linear, polynomial, etc.). 
     At step  308 , the linear velocity may be used to determine the linear velocity function (i.e., the linear velocity may be modified using known constants). Finally, at step  310 , the dimming factor may be determined based on the normalized distance and the linear velocity function. 
     In various embodiments, an electronic device may include a display and control circuitry configured to provide image data to the display. The display may include an array of pixels that form an active area of the display, the active area of the display may have an edge that has at least one rounded corner, and the at least one rounded corner may be defined by a spline. The image data may include a brightness value for each pixel in the array of pixels, the control circuitry may include a multiplication circuit configured to modify the image data by multiplying the image data by dimming factors, each pixel in the array of pixels may have a respective dimming factor, and the dimming factor associated with each pixel may be a function of a linear velocity associated with a location of the respective pixel. 
     The multiplication circuit may be configured to modify the image data by multiplying the brightness value for each pixel in the array of pixels by the dimming factor associated with the pixel. The control circuitry may include display driver circuitry that provides the modified image data to the array of pixels, and the array of pixels may display an image based on the modified image data. The dimming factor associated with each pixel may also be a function of a distance of the respective pixel to the spline. The dimming factor for each pixel may decrease as the distance of the pixel to the spline increases. The distance of the pixel to the spline may be measured as the distance from a center of the pixel to the spline. The dimming factor for pixels that are within the spline may be 1. The dimming factor associated with each pixel may be a function of a normalized distance of the respective pixel to the spline. The dimming factor for pixels that are greater than one pixel width outside of the spline may be 0. The linear velocity associated with the location of each pixel may be determined by a contour of the spline at the location. The edge of the active area of the display may have four sides with four rounded corners. 
     In various embodiments, display circuitry may include an array of pixels configured to display images, a gain table that includes a dimming factor for each pixel in the array of pixels, and a multiplication circuit that is configured to receive image data. The image data may include a brightness value for each pixel in the array of pixels, the multiplication circuit may be configured to multiply the brightness value for each pixel by the dimming factor associated with the pixel to obtain modified image data, and the dimming factor for each pixel may be a function of a distance between the respective pixel and a spline. The display circuitry may also include display driver circuitry configured to provide the modified image data to the array of pixels. 
     In various embodiments, a method of operating a display that has a plurality of pixels and at least one curved edge defined by a spline may include providing image data to the display that includes brightness levels for each pixel in the plurality of pixels and modifying the image data based on dimming factors. Each pixel may have a respective dimming factor and the dimming factor for each pixel may be a function of a linear velocity that is associated with a location of the respective pixel. The method may also include displaying an image using the plurality of pixels based on the modified image data. The dimming factor for each pixel may also be a function of a normalized distance between the respective pixel and the spline. 
     In accordance with an embodiment, an electronic device is provided that includes a display that includes an array of pixels that form an active area of the display, the active area of the display has an edge that has at least one rounded corner, and the at least one rounded corner is defined by a spline, and control circuitry configured to provide image data to the display, the image data includes a brightness value for each pixel in the array of pixels, the control circuitry includes a multiplication circuit configured to modify the image data by multiplying the image data by dimming factors, each pixel in the array of pixels has a respective dimming factor, and the dimming factor associated with each pixel is a function of a linear velocity associated with a location of the respective pixel. 
     In accordance with another embodiment, the multiplication circuit is configured to modify the image data by multiplying the brightness value for each pixel in the array of pixels by the dimming factor associated with the pixel. 
     In accordance with another embodiment, the control circuitry includes display driver circuitry that provides the modified image data to the array of pixels, and the array of pixels displays an image based on the modified image data. 
     In accordance with another embodiment, the dimming factor associated with each pixel is also a function of a distance of the respective pixel to the spline. 
     In accordance with another embodiment, the dimming factor for each pixel decreases as the distance of the pixel to the spline increases. 
     In accordance with another embodiment, the distance of the pixel to the spline is measured as the distance from a center of the pixel to the spline. 
     In accordance with another embodiment, the dimming factor for pixels that are within the spline is 1. 
     In accordance with another embodiment, the dimming factor associated with each pixel is a function of a normalized distance of the respective pixel to the spline. 
     In accordance with another embodiment, the dimming factor for pixels that are greater than one pixel width outside of the spline is 0. 
     In accordance with another embodiment, the linear velocity associated with the location of each pixel is determined by a contour of the spline at the location. 
     In accordance with another embodiment, the edge of the active area of the display has four sides with four rounded corners. 
     In accordance with an embodiment, display circuitry is provided that includes an array of pixels configured to display images, a gain table that includes a dimming factor for each pixel in the array of pixels, a multiplication circuit that is configured to receive image data, the image data includes a brightness value for each pixel in the array of pixels, the multiplication circuit is configured to multiply the brightness value for each pixel by the dimming factor associated with the pixel to obtain modified image data, and the dimming factor for each pixel is a function of a distance between the respective pixel and a spline, and display driver circuitry configured to provide the modified image data to the array of pixels. 
     In accordance with another embodiment, the dimming factor for each pixel decreases as the distance between the pixel and the spline increases. 
     In accordance with another embodiment, the distance between each pixel and the spline is measured as the distance from a center of the respective pixel to the spline. 
     In accordance with another embodiment, the dimming factor for pixels that are within the spline is 1. 
     In accordance with another embodiment, the dimming factor associated with each pixel is a function of a normalized distance between the respective pixel and the spline. 
     In accordance with another embodiment, the dimming factor for pixels that are greater than one pixel width outside of the spline is 0. 
     In accordance with another embodiment, the dimming factor associated with each pixel is also a function of a linear velocity associated with a location of the respective pixel. 
     In accordance with an embodiment, a method of operating a display that has a plurality of pixels and at least one curved edge defined by a spline is provided that includes providing image data to the display, the image data includes brightness levels for each pixel in the plurality of pixels, modifying the image data based on dimming factors, each pixel has a respective dimming factor, and the dimming factor for each pixel is a function of a linear velocity that is associated with a location of the respective pixel and displaying an image using the plurality of pixels based on the modified image data. 
     In accordance with another embodiment, the dimming factor for each pixel is also a function of a normalized distance between the respective pixel and the spline. 
     In accordance with an embodiment, an electronic device is provided that includes a display that includes a plurality of pixels that form an active area of the display, wherein the active area of the display has at least one rounded corner along at least a portion of an edge of the active area of the display, and control circuitry configured to provide image data to the display, wherein the image data comprises a brightness value for each pixel, wherein the control circuitry comprises circuitry configured to modify the image data based on at least one dimming factor, wherein each pixel has a respective dimming factor, and wherein the dimming factor associated with each pixel is associated with at least a location of the respective pixel. 
     In accordance with another embodiment, the circuitry configured to modify the image data comprises a multiplication circuit configured to multiply the brightness value for each pixel by the dimming factor associated with the pixel. 
     In accordance with another embodiment, the control circuitry includes display driver circuitry that provides the modified image data to the plurality of pixels and the plurality of pixels displays an image based on the modified image data. 
     In accordance with another embodiment, the dimming factor associated with each pixel at least is associated with a linear velocity associated with the location of each pixel and the linear velocity is determined at least by a contour of a spline of the at least one rounded corner at the location. 
     In accordance with another embodiment, the dimming factor associated with each pixel is at least associated with a linear velocity associated with the location of the respective pixel and a distance of the respective pixel to a spline of the at least one rounded corner. 
     In accordance with another embodiment, the dimming factor for each pixel decreases as the distance of the pixel to the spline increases. 
     In accordance with another embodiment, the distance of the pixel to the spline is measured as a distance from a center of the pixel to the spline. 
     In accordance with another embodiment, the dimming factor for pixels that are within a predetermined distance to the spline is 1. 
     In accordance with another embodiment, the dimming factor for pixels that are greater than one pixel width outside of the spline is 0. 
     In accordance with another embodiment, the dimming factor associated with each pixel at least is associated with a normalized distance of the respective pixel to a spline of the at least one rounded corner. 
     In accordance with another embodiment, the display has four sides with four rounded corners. 
     In accordance with an embodiment display circuitry for a display is provided including a plurality of pixels configured to display images, a multiplication circuit that is configured to receive image data, wherein the image data includes a brightness value for each pixel of the plurality of pixels, wherein the multiplication circuit is configured at least to multiply the brightness value for each pixel by a dimming factor associated with the pixel to obtain modified image data, and wherein the dimming factor for each pixel at least is a function of a distance between the respective pixel and a spline of the display, and display driver circuitry configured to provide the modified image data to the plurality of pixels. 
     In accordance with another embodiment, the display circuitry also includes a gain table that includes the dimming factor for each pixel, wherein the dimming factor for each pixel decreases as the distance between the pixel and the spline increases. 
     In accordance with another embodiment, the distance between each pixel and the spline is measured as a distance from a center of the respective pixel to the spline. 
     In accordance with another embodiment, the dimming factor for pixels that are within a predetermined distance to the spline is 1. 
     In accordance with another embodiment, the dimming factor for pixels that are greater than one pixel width outside of the spline is 0. 
     In accordance with another embodiment, the dimming factor associated with each pixel at least is associated with a normalized distance between the respective pixel and the spline. 
     In accordance with another embodiment, the dimming factor associated with each pixel is also at least associated with a linear velocity associated with a location of the respective pixel. 
     In accordance with an embodiment, a method of operating a display that has a plurality of pixels and at least one curved edge is provided that includes providing image data to the display, wherein the image data comprises brightness levels for each pixel in the plurality of pixels, modifying the image data based on dimming factors, wherein each pixel has a respective dimming factor, and wherein the dimming factor for each pixel at least is associated with a location of the respective pixel, and displaying an image using the plurality of pixels based on the modified image data. 
     In accordance with another embodiment, the dimming factor for each pixel at least is associated with a linear velocity that is associated with the location of the respective pixel and the dimming factor for each pixel at least is associated with a normalized distance between the respective pixel and a spline of the at least one curved edge. 
     The foregoing is merely illustrative and various modifications can be made by those skilled in the art without departing from the scope and spirit of the described embodiments. The foregoing embodiments may be implemented individually or in any combination.

Metadata:
Filing Date: 20190328
Publication Date: 20200519
Grant Date: 20200519
Priority Date: 20160804
Inventors: JIN, JIAYI
CHO, Myung-Je
SACCHETTO, PAOLO
YAO, WEIJUN
Assignee: APPLE INC
CPC Classifications: [{"code": "G09G3/20", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2310/0232", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/0285", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G3/3607", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2320/0285", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/0285", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/0626", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2310/0232", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2310/0232", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/0626", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/3607", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G3/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "G09G2310/0232", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G2320/0285", "inventive": false, "first": false, "tree": "[]"}, {"code": "G09G3/20", "inventive": true, "first": true, "tree": "[]"}, {"code": "G09G2320/0686", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 59501550