Apple Inc.

Suraj P Gorkhali

Victor H Yin

Mookyung Son

Daming Xu

Jun Qi

Rong Liu

Heesang Suh

Joshua A Spechler

Ling Han

Wei Lv

Yu P Sun

Wenyong Zhu

Chenhua You

Xinyu Zhu

Adria Fores Herranz

Ziruo Hong

Zhenyue Luo

Juan He

Janos C Keresztes

Pee Khiam So

Hung Sheng Lin

Zhibing Ge

Marc Albrecht

Xiaokai Li

Chengrui Le

Tobias Jung

Ross Thompson

Aaron L Holsteen

Yi-Pai Huang

Thomas O Henry

Yufeng Yan

Fang-Cheng Lin

Judith C Segura

Shin-Ying Lu

Mingkun Li

Jay Mayur Khandhar

Shaofeng Liu

Edward H Kang

Mahnaz Mohammadi

Yansong Liu

He Li

Alexander P Yu

An electronic device may include a display having an array of pixels and a backlight that provides backlight illumination for the array of pixels. The backlight may be a direct-lit backlight with a two-dimensional array of light-emitting diodes operable in a local dimming scheme. The electronic device may include control circuitry that provides pixel signals to the array of pixels and backlight signals to the backlight. The control circuitry may adjust the pixel signals and the backlight signals to compensate for brightness and color non-uniformity in the backlight. To compensate for image-dependent backlight non-uniformity, the control circuitry may simulate artificial backlight data based on the target image to be displayed and stored point spread information. To compensate for white-point-dependent backlight non-uniformity, the control circuitry may use measured actual backlight data that describes color variations across the backlight for a given target white point.

Displays with reduced color non-uniformity

A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a direct-lit backlight unit. The backlight unit may include an array of light-emitting diodes on a printed circuit board. The backlight unit may include first, second, and third light spreading layers formed over the array of light-emitting diodes. A color conversion layer may be formed over the first, second, and third light spreading layers. First and second brightness enhancement films may be formed over the color conversion layer.

Displays with direct-lit backlight units

A display may have a pixel array such as a liquid crystal pixel array. The pixel array may be illuminated with backlight illumination from a backlight unit. The backlight unit may include a printed circuit board, a plurality of light-emitting diodes mounted on the printed circuit board, at least one light spreading layer formed over the printed circuit board that spreads light received from the plurality of light-emitting diodes, a partially reflective layer formed over the at least one light spreading layer, a color conversion layer formed over the partially reflective layer, a collimating layer formed over the color conversion layer, a brightness enhancement film formed over the collimating layer, and a diffuser formed over the brightness enhancement film. The at least one light spreading layer may include two light spreading layers with elongated protrusions that are rotated relative to each other.

Displays with direct-lit backlight units and color conversion layers

An electronic device may include display layers such as liquid crystal display layers and a backlight unit that provides illumination for the display layers. The backlight unit may include light-emitting diodes that emit light into the edge of a light guide film. To minimize the inactive area of the display, the light-emitting diodes may be tightly spaced to approximate a line light source instead of point light sources. Color and/or luminance compensation layers may be incorporated at various locations within the backlight structures to ensure that the backlight provided to the display layers is homogenous. A thin-film transistor layer of the display may be coupled to a printed circuit board by a flexible printed circuit. The flexible printed circuit may have additional solder mask layers to improve robustness, may include encapsulation, and may have traces with a varying pitch.

Electronic device display with a backlight and control circuitry that corrects pixel data to reduce transition artifacts

Displays with direct-lit backlight units and light spreading structures

An electronic device has a display with a pixel array overlapping an array of temperature sensors. Control circuitry in the device may gather temperature measurements from the temperature sensor array. The control circuitry may apply a global offset to the temperature measurements and may apply a damping factor to the globally offset measurements to produce a two-dimensional temperature profile for the display. A look-up table or other data structure may be used to store information on pixel color correction gain values as a function of temperature. This temperature-gain information and temperature information from the two-dimensional temperature profile may be used by display circuitry in the device to display color-corrected images on the display.

Electronic devices with temperature-compensated displays

Growing community of inventors

San Jose, CA, United States of America

Suraj P Gorkhali