US-12626629-B2 - Sub-pixel uniformity correction clip compensation systems and methods

US12626629B2US 12626629 B2US12626629 B2US 12626629B2US-12626629-B2

Abstract

An electronic device may include an electronic display having display pixels and pixel drive circuitry that selects an analog voltage for the display pixels based on a first gray-to-voltage mapping and display image data that is based on compensated image data. The electronic display may also include image processing circuitry that receives input image data in a gray level domain, converts the input image data to a voltage domain based on a second gray-to-voltage mapping different from the first, and applies voltage compensations to voltage levels of the input image data in the voltage domain to generate compensated voltage data. The image processing circuitry may also convert the compensated voltage data from the voltage domain to the gray level domain to generate the compensated image data based on a voltage-to-gray mapping that is the inverse of the first gray-to-voltage mapping.

Inventors

Maofeng YANG
Pankul Dhingra
Rangarajan Krishnan
Sreenath Rao Vantaram
Weijun Yao
Xiaqing Dong
Aaron J Perley
Arthur L Spence
Chung Kai Chow
David A Doyle
Giovanni Azzellino
Jen-Wei Tsai
Kyung Hoae Koo
Michael H Lim

Assignees

APPLE INC.

Dates

Publication Date: 20260512
Application Date: 20240923

Claims (20)

1 . An electronic device comprising: an electronic display comprising: a plurality of display pixels; and pixel drive circuitry configured to receive display image data and select an analog voltage for a display pixel of the plurality of display pixels based on the display image data and a first gray-to-voltage mapping; and image processing circuitry coupled to the electronic display and configured to: receive input image data in a gray level domain; convert the input image data from the gray level domain to a voltage domain, generating voltage data based on a second gray-to-voltage mapping different from the first gray-to-voltage mapping; apply a voltage compensation value to a voltage level, of the voltage data, corresponding to the display pixel to generate compensated voltage data; determine whether to convert the compensated voltage data from the voltage domain to the gray level domain via a first voltage-to-gray mapping or a second voltage-to-gray mapping at least in part by comparing a difference between a first voltage level of the second gray-to-voltage mapping and a second voltage level of the second gray-to-voltage mapping to a threshold voltage value, wherein the first voltage-to-gray mapping correlates a first range of voltage levels of the voltage domain to a range of gray levels of the gray level domain, wherein the second voltage-to-gray mapping correlates a second range of voltage levels of the voltage domain to the range of gray levels of the gray level domain, wherein the first range of voltage levels of the voltage domain is larger than the second range of voltage levels of the voltage domain; and convert, based on the comparison, the compensated voltage data from the voltage domain to the gray level domain to generate compensated image data based on the first voltage-to-gray mapping, wherein the first voltage-to-gray mapping is an inverse of the first gray-to-voltage mapping, and wherein the display image data is based on the compensated image data.
2 . The electronic device of claim 1 , wherein the image processing circuitry is configured to generate the first gray-to-voltage mapping based on the second gray-to-voltage mapping.
3 . The electronic device of claim 2 , wherein the second gray-to-voltage mapping comprises a relationship between the range of gray levels of the gray level domain and the second range of voltage levels of the voltage domain corresponding to respective luminance outputs of an average display pixel of the plurality of display pixels, and wherein the respective luminance outputs correspond to an optical calibration profile.
4 . The electronic device of claim 2 , wherein the second gray-to-voltage mapping is preset as a property of the electronic display during manufacturing.
5 . The electronic device of claim 1 , wherein the second voltage-to-gray mapping is an inverse of the second gray-to-voltage mapping.
6 . The electronic device of claim 5 , wherein the range of gray levels of the gray level domain is increased only below a threshold tap point of the second voltage-to-gray mapping.
7 . The electronic device of claim 1 , wherein if the difference is less than the threshold voltage value, the image processing circuitry is configured to convert the compensated voltage data from the voltage domain to the gray level domain via the first voltage-to-gray mapping.
8 . The electronic device of claim 1 , wherein the plurality of display pixels comprises a plurality of organic light emitting diodes (OLEDs).
9 . The electronic device of claim 1 , wherein the voltage compensation value comprises a voltage offset configured to compensate for a sub-pixel non-uniformity of the display pixel relative to an average pixel of the plurality of display pixels.
10 . The electronic device of claim 1 , wherein the first voltage-to-gray mapping comprises a calibrated voltage-to-gray mapping.
11 . A method comprising: receiving, via image processing circuitry, input image data in a gray level domain; converting, via the image processing circuitry, the input image data from the gray level domain to a voltage domain based on a gray-to-voltage mapping to generate voltage data; applying, via the image processing circuitry, a voltage compensation value to a voltage level, of the voltage data, corresponding to a display pixel of an electronic display to generate compensated voltage data; determining, via the image processing circuity, whether to convert the compensated voltage data from the voltage domain to the gray level domain via a voltage-to-gray mapping or a calibrated voltage-to-gray mapping at least in part by comparing a difference between a first voltage level of the gray-to-voltage mapping and a second voltage level of the gray-to-voltage mapping to a threshold voltage value, wherein the calibrated voltage-to-gray mapping correlates a first range of voltage levels of the voltage domain to a range of gray levels of the gray level domain, wherein the voltage-to-gray mapping correlates a second range of voltage levels of the voltage domain to the range of gray levels of the gray level domain, and wherein the first range of voltage levels of the voltage domain is larger than the second range of voltage levels of the voltage domain; and converting, via the image processing circuitry and based on the comparison, the compensated voltage data from the voltage domain to the gray level domain to generate compensated image data based on the calibrated voltage-to-gray mapping.
12 . The method of claim 11 , comprising: receiving, via pixel drive circuitry of the electronic display, display image data, wherein the display image data is based on the compensated image data; selecting, via the pixel drive circuitry, an analog voltage for the display pixel based on the display image data and a calibrated gray-to-voltage mapping, wherein the calibrated gray-to-voltage mapping is an inverse of the calibrated voltage-to-gray mapping; and supplying, via the pixel drive circuitry, the analog voltage to the display pixel.
13 . The method of claim 11 , wherein the first range of voltage levels of the voltage domain is increased below a threshold tap point of the voltage-to-gray mapping and above the threshold tap point of the voltage-to-gray mapping, and wherein the voltage-to-gray mapping is an inverse of the gray-to-voltage mapping.
14 . The method of claim 11 , wherein the voltage compensation value comprises a voltage offset configured to compensate for a sub-pixel non-uniformity of the display pixel relative to an average pixel of the electronic display.
15 . The method of claim 11 , comprising determining to convert the compensated voltage data from the voltage domain to the gray level domain via the calibrated voltage-to-gray mapping based on determining the difference is less than the threshold voltage value.
16 . The method of claim 15 , wherein if the difference is greater than the threshold voltage value, the image processing circuitry is configured to convert the compensated voltage data from the voltage domain to the gray level domain via the voltage-to-gray mapping.
17 . A non-transitory, machine-readable medium comprising instructions, wherein, when executed by one or more processors, the instructions cause the one or more processors to perform operations or to control circuitry that performs the operations, wherein the operations comprise: receiving input image data in a gray level domain; converting the input image data from the gray level domain to a voltage domain based on a gray-to-voltage mapping to generate voltage data; applying a voltage compensation value to a voltage level, of the voltage data, corresponding to a display pixel of an electronic display to generate compensated voltage data; determining whether to convert the compensated voltage data from the voltage domain to the gray level domain via a voltage-to-gray mapping or a calibrated voltage-to-gray mapping at least in part by comparing a difference between a first voltage level of the gray-to-voltage mapping and a second voltage level of the gray-to-voltage mapping to a threshold voltage value, wherein the voltage-to-gray mapping is an inverse of the gray-to-voltage mapping, wherein the calibrated voltage-to-gray mapping correlates a first range of voltage levels of the voltage domain to a range of gray levels of the gray level domain, wherein the voltage-to-gray mapping correlates a second range of voltage levels of the voltage domain to the range of gray levels of the gray level domain, and wherein the first range of voltage levels of the voltage domain is larger than the second range of voltage levels of the voltage domain; and converting, based on the comparison, the compensated voltage data from the voltage domain to the gray level domain to generate compensated image data based on the calibrated voltage-to-gray mapping.
18 . The non-transitory, machine-readable medium of claim 17 , wherein the operations comprise selecting an analog voltage for the display pixel based on display image data and a calibrated gray-to-voltage mapping, wherein the display image data is based on the compensated image data, and wherein the calibrated gray-to-voltage mapping is an inverse of the calibrated voltage-to-gray mapping.
19 . The non-transitory, machine-readable medium of claim 18 , wherein the operations comprise supplying the analog voltage to the display pixel.
20 . The non-transitory, machine-readable medium of claim 17 , wherein the voltage compensation value comprises a voltage offset configured to compensate for a sub-pixel non-uniformity of the display pixel relative to an average pixel of the electronic display.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63/599,394, entitled “Sub-Pixel Uniformity Correction Clip Compensation Systems and Methods,” and filed Nov. 15, 2023, which is incorporated by reference herein in its entirety. SUMMARY A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit the scope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below. The present disclosure generally relates to electronic devices with display panels, and more particularly, to schemes for sub-pixel uniformity correction (SPUC) on a display panel. For example, image processing circuitry may include a SPUC block to adjust the applied analog voltage (e.g., by pixel drive circuitry) to the display pixels by adjusting the image data provided thereto. In general, the SPUC block may convert input image data from a gray level domain to a voltage domain, compensate the voltage data, and convert the compensated voltage data to the gray level domain. However, as presently recognized, in some scenarios, the voltage compensation may decrease or increase the value of the voltage data to a level that is clipped by the minimum or maximum gray level, respectively, when converted back to the voltage domain. As such, in some embodiments, the SPUC block may utilize a calibrated V2G mapping that expands the headroom and/or footroom of the gray level domain with respect to the voltage domain. In other words, a lower voltage data level may map to lowest gray level and/or a higher voltage data level may map to the highest gray level relative to the G2V mapping used prior to the voltage compensation. The calibrated V2G mapping may generate, from the compensated voltage data, compensated image data that is indicative of the same range of luminances, but a wider range of voltages than the input image data. Furthermore, the compensated image data may be provided to the pixel drive circuitry to drive the display pixels at the compensated voltages. Additionally, the pixel drive circuitry may utilize a calibrated G2V (gray-to-voltage) mapping (e.g., an inverse mapping of the calibrated V2G mapping) to obtain the desired voltage levels for driving the display pixels. In other words, the extended voltage range of the compensated voltage data may be realized at the pixel drive circuitry, and the analog voltages corresponding to the compensated voltage data may be supplied to the display pixels. As such, by utilizing the calibrated V2G mapping and the calibrated G2V mapping, the headroom and/or footroom in the gray level domain may be increased to accommodate the compensated voltage data levels that would otherwise be clipped by the gray level domain. Various refinements of the features noted above may exist in relation to various aspects of the present disclosure. Further features may also be incorporated in these various aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to one or more of the illustrated embodiments may be incorporated into any of the above-described aspects of the present disclosure alone or in any combination. The brief summary presented above is intended only to familiarize the reader with certain aspects and contexts of embodiments of the present disclosure without limitation to the claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS Various aspects of this disclosure may be better understood upon reading the following detailed description and upon reference to the drawings in which: FIG. 1 is a schematic diagram of an electronic device that includes an electronic display, in accordance with an embodiment; FIG. 2 is an example of the electronic device of FIG. 1 in the form of a handheld device, in accordance with an embodiment; FIG. 3 is another example of the electronic device of FIG. 1 in the form of a tablet device, in accordance with an embodiment; FIG. 4 is another example of the electronic device of FIG. 1 in the form of a computer, in accordance with an embodiment; FIG. 5 is another example of the electronic device of FIG. 1 in the form of a watch, in accordance with an embodiment; FIG. 6 is another example of the electronic device of FIG. 1 in the form of a computer, in accordance with an embodiment; FIG. 7 is a schematic diagram of the image processing circuitry of FIG. 1 including a sub-pixel uniformity correction (SPUC) block, in accordance with an embodiment; FIG. 8 is a schematic diagram of a gamma generator in electrical communication with a portion of an electronic display of FIG. 1, in accordance with an embodiment; FIG. 9 is a schematic diagram of SPUC block of FIG. 7, in accordance with an