Apple Inc.

Chuang Qian

Abbas Jamshidi Roudbari

Ting-Kuo Chang

Shyuan Yang

Tsung-Ting Tsai

Chin-Wei Lin

Cheng-Chih Hsieh

Yurii Morozov

Rui Liu

Weijun Yao

Shih-Chang Chang

Abbas Jamshidi-Roudbari

Aleksandr N Polyakov

Tiffany T Moy

Sabino Joseph Pietrangelo, Ii

Michael H Lim

Warren S A Rieutort-Louis

Xia Li

Shih Chang Chang

Hopil Bae

Warren S Rieutort-Louis

Mahdi Farrokh Baroughi

Tore Nauta

Injae Hwang

David Andrew Doyle

Christophe Blondin

Yifan Zhang

Jiayi Jin

Yuchi Che

Yue Jack Chu

Tae-Wook Koh

Majid Gharghi

Patrick B Bennett

Ashray Vinayak Gogte

Maofeng Yang

Saif Choudhary

Yongjun Li

Kiran S Pillai

Ricardo A Peterson

Mathew K Mathai

Ruo-Gu Huang

James P Landry

Jiye Lee

Sebastian Knitter

Kyung Hoae Koo

Matthew Dominic Hollands

Ze Yuan

Matthew J Schwendeman

Kenny Kim

Yue Qu

Tiffany Tang Moy

Sabino Joseph Pietrangelo Ii

A pulse width modulation and amplitude modulation driving system for a display panel, including related circuits and methods of operation, are described. In an embodiment, a display panel includes a thin film transistor layer comprising a plurality of subpixel circuits. Each subpixel circuit may include a drive transistor, a comparator, and a switch. A plurality of light emitting diodes (LEDs), such as micro-LEDs, may be connected to the plurality of subpixel circuits. Each subpixel circuit can control an LED based on a current amplitude controlled by the drive transistor and a current pulse width controlled by the comparator and the switch. Other aspects are also described and claimed.

Pulse width modulation and amplitude modulation driving system for display panels

A display may have an array of organic light-emitting diode display pixels operating at a low refresh rate. Each display pixel may have six thin-film transistors and one capacitor. One of the six transistors may serve as the drive transistor and may be compensated using the remaining five transistors and the capacitor. One or more on-bias stress operations may be applied before threshold voltage sampling to mitigate first frame dimming. Multiple anode reset and on-bias stress operations may be inserted during vertical blanking periods to reduce flicker and maintain balance and may also be inserted between successive data refreshes to improve first frame performance. Two different emission signals controlling each pixel may be toggled together using a pulse width modulation scheme to help provide darker black levels.

Electronic devices with low refresh rate display pixels

Visibility of the metal mesh touch electrodes can be mitigated using one or more mitigation techniques. In some examples, the boundary between touch electrodes and/or the boundary between a touch electrode and a routing trace of another touch electrode and/or the boundary between two routing traces can be non-linear. In some examples, dummy cuts can be made within an area of a touch electrode region (e.g., while maintaining the same electrical potential for the touch electrode region). In some examples, notches can be made in the metal mesh. In some examples, the location of cuts and/or notches can be optimized to mitigate visibility of the metal mesh. In some examples, some or all of the visibility mitigations may be used in combination in a touch screen.

Metal mesh touch electrodes with visibility mitigations

A display may have both a full pixel density region and a pixel removal region with a plurality of high-transmittance areas that overlap an optical sensor. Each high-transmittance area may be devoid of thin-film transistors and other display components. To improve transmission while maintaining satisfactory touch sensing performance, one or more segments of the touch sensor metal in the pixel removal region may have a reduced width relative to the touch sensor metal in the full pixel density region and/or one or more segments of the touch sensor metal in the pixel removal region may be omitted relative to the touch sensor metal in the full pixel density region. To mitigate a different appearance between the pixel removal region and the full pixel density region at off-axis viewing angles, the position of the touch sensor metal in the pixel removal region may be tuned.

Devices with displays having transparent openings and touch sensor metal

An electronic device may include an electronic display including display pixels to display an image based on compensated image data. The electronic display may also include a stressed reference pixel to exhibit burn-in related aging in response to one or more stress sessions and a non-stressed reference pixel configured to not undergo the one or more stress sessions. Additionally, the electronic device may include image processing circuitry to determine a panel-specific aging profile based on a comparison between one or more properties of the stressed reference pixel and the one or more properties of the non-stressed reference pixel. The image processing circuitry may also generate one or more gain maps based on the panel-specific aging profile and generate the compensated image data by applying the one or more gain maps to input image data.

Reference pixel stressing for burn-in compensation systems and methods

A display driver is disclosed that reduces first frame dimming and flicker in light-emitting diode pixels of a display device. The display driver may receive a display brightness value and determine a value of a dynamic supply voltage parameter based on the display brightness value. Over a first time interval, the display driver may apply a supply voltage that is based on the dynamic supply voltage parameter to one of a gate of a drive transistor of a light-emitting-diode circuit and a channel of the drive transistor. Over a second time interval, the display driver may apply a parking voltage to an anode of a light-emitting diode of the light-emitting-diode circuit and to the channel of the drive transistor. The value of the parking voltage may be below a threshold voltage of the light-emitting diode and correspond to the value of the dynamic supply voltage parameter.

Adaptive parking voltage tuning to optimize display front-of-screen with dynamic supply voltage

Electronic devices may include displays having organic light-emitting diode pixels, display driver circuitry, and gate driver circuitry. To reduce the amount of space occupied in the inactive area of a display by the gate driver circuitry, one or more of the shift registers in the gate driver circuitry may include register circuits that are shared by multiple rows of pixels. Different drivers may use different clock frequencies to ensure synchronous operation of the display even when some register circuits share pixel rows. For increased flexibility in the arrangement of the register circuits in the shift registers, one or more of the shift registers may be split across the active area of the display. In some cases, one of the emission drivers may be omitted from the gate driver circuitry and a single emission driver may provide multiple emission control signals for the pixels.

Displays with gate driver circuitry having shared register circuits

A display may have an array of organic light-emitting diode display pixels operating at a low refresh rate. Each display pixel may include a drive transistor coupled in series with one or more emission transistors and a respective organic light-emitting diode (OLED). A semiconducting-oxide transistor may be coupled between a drain terminal and a gate terminal of the drive transistor to help reduce leakage during low-refresh-rate display operations. A silicon transistor may be further interposed between the semiconducting-oxide transistor and the gate terminal of the drive transistor. One or more capacitor structures may be coupled to the source terminal and/or the drain terminal of the semiconducting-oxide transistor to reduce rebalancing current that might flow through the semiconducting-oxide transistor as it is turned off. Configured in this way, any emission current flowing through the OLED will be insensitive to any potential drift in the threshold voltage of the semiconducting-oxide transistor.

Electronic devices having low refresh rate display pixels with reduced sensitivity to oxide transistor threshold voltage

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Santa Clara, CA, United States of America

Chuang Qian