Apple Inc.

Google Inc.

Appl Inc.

Sang Young Youn

Yafei Bi

Sun-il Chang

Wei Hsin Yao

Minhyuk Choi

Jean-Pierre Simon Guillou

Koorosh Aflatooni

Mohammad Ali Jangda

Tsung-Ting Tsai

Sangmoo Choi

Chin-Wei Lin

Hopil Bae

Hung Sheng Lin

Wonjae Choi

Hyunwoo Nho

Chien-Hui Wen

Hyunchul Kim

Kingsuk Brahma

Vasudha Gupta

Rui Zhang

Shafiq M Jamal

David A Stronks

Taif Ahmed Syed

Mohammad Hajirostam

Wei Y Yao

Yun Yu Wang

Shih Chang Chang

Cheng Kai Chen

Rui Liu

Ahmad Al-Dahle

Young Bae Park

Wey-Jiun Lin

Shengkui Gao

Jae Won Choi

Sang Ha Kim

Paolo Sacchetto

Jie Won Ryu

Mohammad Bagher Vahid Far

Weijun Yao

Marc Joseph DeVincentis

Prashant Mandlik

Hyunsoo Kim

Zhen Zhang

Kevin J White

Myung-Je Cho

Mir Bahram Ghaderi

Saman Saeedi

Anshi Liang

Chang Ju Kang

Xiaoping Bai

Guangmao Xing

Katherine W Song

Taif Ahmed Said

Ji Hoon Lee

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for brightness control for under-display fingerprint sensor are disclosed. A method includes receiving, at a computing device, an indication to activate an under-display sensor that is located underneath a display of the computing device; activating a collection of LEDs of the display to provide illumination for the under-display sensor, including activating an LED in the collection of LEDs by: establishing, by drive circuitry of the LED, a first overdriven voltage across an LED-driving transistor that is arranged to energize the LED; establishing a second overdriven voltage across the LED-driving transistor; and establishing a steady state voltage across the LED-driving transistor; and activating the under-display sensor by reading a signal from the under-display sensor once the collection of LEDs has activated, including once the steady state voltage has been programmed across the LED-driving transistor.

Brightness control for under-display sensor

PWM-frame rate misalignment is mitigated through implementation of a discrete variable refresh rate (VRR) scheme. A target frame rate is limited to a frame rate selected from only those frame rates that facilitate alignment of each frame period to a specified edge of a PWM cycle of a brightness control signal of a display panel. This alignment results in each frame period at the selected frame rate starting at a same point in a corresponding PWM cycle and ending at a same point in a corresponding PWM cycle to help ensure a constant effective duty cycle across each successive frame period, which in turn mitigates perception of flicker that otherwise would arise. Further, the discrete VRR scheme can employ a compensation mode for compensating for the delay in rendering or otherwise obtaining a frame for display so as to maintain a consistent duty cycle in the brightness control signal.

Variable refresh rate control using PWM-aligned frame periods

Rendering images on an active area of an OLED includes rendering images on the active area of the display panel with a plurality of different frame rates. For a plurality of the different frame rates having a frame rate that matches or is above a threshold frame rate, an image refresh operation is performed once per frame period and a self-refresh operation is not performed during the frame period. When rendering images on the active area, for at least one of the different frame rates having a frame rate that is lower than the threshold frame rate, an image refresh operation is performed once per frame period and a self-refresh operation is performed at least once during the frame period.

Power saving in OLED displays with multiple refresh rates

An electronic device may have a display with an array of pixels. The device may have an array of components such as an array of light sensors for capturing fingerprints of a user through an array of corresponding transparent windows in the display. A capacitive touch sensor, proximity sensor, force sensor, or other sensor may be used by control circuitry in the device to monitor for the presence of a user's finger over the array of light sensors. In response, the control circuitry can direct the display to illuminate a subset of the pixels, thereby illuminating the user's finger and causing reflected light from the finger to illuminate the array of light sensors for a fingerprint capture operation. The display may have display driver circuitry that facilitates the momentary illumination of the subset of pixels with uniform flash data while image data is displayed in other portions of the display.

Display with localized brightness adjustment capabilities

A first image is rendered on an active area of an OLED display panel with a first refresh rate that is below a threshold refresh rate and, subsequent to rendering the first image with the first refresh rate, a second image that is different from the first image is rendered on the active area, where the rendering of the second image includes rendering a number of initial frames of the second image at a second refresh rate that is at or above the threshold refresh rate. After rendering the number of initial frames of the second image at the second refresh rate, additional frames of the second image on the active area are rendered with the first refresh rate, where the number of initial frames is greater than 1.

Image change sequence to prevent optical artifacts in low refresh rate AMOLED displays

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for remapping for mixed dynamic range content. In one aspect, a method for remapping for mixed dynamic range content, the method includes obtaining an image to be displayed that includes both first dynamic range content and second dynamic range content, determining that the image includes first dynamic range content at a first pixel, determining a first remapped value for the first pixel based on a lookup table for first dynamic range content and an initial value for the first pixel, providing the first remapped value for the first pixel for display, determining that the image includes second dynamic range content at a second pixel, determining a second remapped value for the second pixel based on a second initial value for the second pixel, and providing the second remapped value for the second pixel for display.

Remapping for mixed dynamic range content

An example method includes estimating, based on content to be displayed at a display of a mobile computing device at a future time, an amount of power to be used by the display at the future time; selecting, based on the estimated power level, a power converter of a plurality of power converters of the mobile computing device, each of the plurality of power converters optimized for a different output power range; and causing electrical power from the selected power converter to be supplied to the display at the future time.

Dynamic power converter switching for displays based on predicted power usage

A frame generation subsystem renders a sequence of frames and a display control subsystem provides a brightness control signal configured to control a brightness of frames displayed at a display panel via pulse width modulation (PWM) of the brightness control signal and determines a deviation in a duty cycle of a first PWM period of the brightness control signal from a default duty cycle resulting from a delayed rendering of a frame. The display control subsystem adjusts a duty cycle of at least a second PWM period to compensate for the deviation in the duty cycle of the first PWM period. The resulting average duty cycle of the brightness control signal over the two frame periods is approximately equal to a default duty cycle and thereby mitigates viewable flicker resulting from the duty cycle change caused by the delayed rendering.

Display PWM duty cycle compensation for delayed rendering

A method, includes: (i) receiving information about an ambient light level; (ii) receiving image frame data for an active matrix display panel with an array of pixels each having a light emitting diode (LED) and a pixel circuit to control current supplied to the LED; (iii) selecting a selected current-resistance compensation (IRC) setting based on the information about the ambient light value; (iv) selecting a selected source voltage level based on the selected IRC setting that was selected by the computing system; (v) generating compensated image frame data for the image frame based on the received image frame data and the selected IRC setting; and (vi) displaying the image frame by supplying data signals based on the compensated image frame data to corresponding pixels from the array of pixels, while applying a source voltage corresponding to the selected source voltage level to all of the pixels.

Dynamic IRC and ELVSS for display device

This document describes techniques and apparatuses for a high-brightness mode on an organic light emitting diode (OLED) display. The techniques and apparatuses set a high-brightness value in a register of a display driver integrated circuit (DDIC) associated with the OLED display of on electronic device. A processor of the electronic device provides a fewer-pulses command to the DDIC, which adjusts a pulse number to control the OLED display at fewer pulses per period. A gamma correction is determined based on the high-brightness value and used to alter content to be presented on the OLED display. As a result, fewer pulses are used in combination with the gamma correction to provide content on the OLED display at a high brightness.

High-brightness mode on an OLED display

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for gamma lookup table compression. In one aspect, a method includes obtaining a gamma value for a pixel of an image to be shown on a display, determining a base gamma value based on a base lookup table that corresponds to a base display condition, determining a delta gamma value based on a delta lookup table that corresponds to a current display condition for the pixel, determining a remapped gamma value for the pixel based on a combination of the base gamma value and the delta gamma value, and providing the remapped gamma value to be shown on the display.

Gamma lookup table compression

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for three sub-color correction based on two-dimensional graphs. In an aspect, a method includes obtaining an image to be shown on a display, determining three sub-color values of a particular pixel in the image, including a first sub-color value for a first sub-color, a second sub-color value for a second sub-color, and a third sub-color value for a third sub-color of the particular pixel, obtaining a representation of a two-dimensional graph of color-correction curves, selecting a selected color-correction curve to use to correct the first sub-color value based on both the second sub-color value and the third sub-color value, determining a corrected first sub-color value based on the first sub-color value, and outputting the image using the corrected first sub-color value instead of the first sub-color value.

Three sub-color correction based on two-dimensional graphs

Growing community of inventors

Cupertino, CA, United States of America

Sang Young Youn