Abstract:
An electronic device (10) comprises a display (12) and a controller (58). The controller (58) is configured to determine a change in a refresh rate of the display (1)2 from a first frequency to a second frequency. The controller (58) is also configured to selectively generate a control signal configured to control emission of a light emitting diode (54) of a display pixel (40) of the display (12) based on the first frequency.
Abstract:
A display may have an array of organic light-emitting diode display pixels. Each display pixel may have a light-emitting diode that emits light under control of a drive transistor. Each display pixel may also have control transistors for compensating and programming operations. The array of display pixels may have rows and columns. Row lines may be used to apply row control signals to rows of the display pixels. Column lines (data lines) may be used to apply display data and other signals to respective columns of display pixels. A bottom conductive shielding structure may be formed below each drive transistor. The bottom conductive shielding structure may serve to shield the drive transistor from any electric field generated from the adjacent row and column lines. The bottom conductive shielding structure may be electrically floating or coupled to a power supply line.
Abstract:
A display may have an array of organic light-emitting diode display pixels. Each display pixel may have a light-emitting diode that emits light under control of a drive transistor. Each display pixel may also have control transistors for compensation and programming operations. 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. The capacitor may have a first terminal coupled to the gate of the drive transistor and a second terminal coupled to the light-emitting diode. In one embodiment, two scan control signals and two emission control signals may be used for each row of display pixels. In another embodiment, a single scan control signal and a single emission control signal may be formed for each row of display pixels.
Abstract:
An organic light-emitting diode display may have an array of pixels. Each pixel may have an organic light-emitting diode with an anode (44) and cathode (42). The anodes may be formed from a patterned layer of metal. Thin-film transistor circuitry in the pixels may include transistors such as drive transistors (TD) and switching transistors (200). Data lines may supply data signals to the pixels and horizontal control lines may supply control signals to the gates of the transistors. A switching transistor may be coupled between a voltage initialization line (202) and each anode. The voltage initialization lines and capacitor structures in the thin-film transistor circuitry may be formed using a layer of metal that is different than the layer of metal that forms the anodes.
Abstract:
An electronic device may include a display and an optical sensor formed underneath the display. The electronic device may include a plurality of transparent windows that overlap the optical sensor. The resolution of the display panel may be reduced in some areas due to the presence of the transparent windows. To mitigate diffraction artifacts, a first sensor (13-1) may sense light through a first pixel removal region having transparent windows arranged according to a first pattern. A second sensor (13-2) may sense light through a second pixel removal region having transparent windows arranged according to a second pattern that is different than the first pattern. The first and second patterns of the transparent windows may result in the first and second sensors having different diffraction artifacts. Therefore, an image from the first sensor may be corrected for diffraction artifacts based on an image from the second sensor.
Abstract:
An electronic device may include a display such as a light-emitting diode display. The electronic device may be a head-mounted device that provides a virtual reality or augmented reality environment to a user. To reduce artifacts in the display, a display may be operable in both a normal scanning mode and a partial scanning mode. In the normal scanning mode, every row of the display may be enabled to emit light in each frame. In the partial scanning mode, only a subset of the rows of the display may be enabled to emit light in each frame. The display may have a higher refresh rate in the partial scanning mode than in the normal scanning mode. To ensure uniform transistor stress across the display, the scanning driver for the display may scan the disabled rows in the partial scanning mode even though the rows will not be used to emit light.
Abstract:
A display may have an array of pixels arranged in rows and columns. Display driver circuitry may load data into the pixels via data lines that extend along the columns. The display driver circuitry may include gate driver circuitry that supplies horizontal control signals to rows of the pixels. The horizontal control signals may include emission enable signals for controlling emission enable transistors and scan signals for controlling switching transistors. During an emission phase of operation for the display, the emission enable signal may be pulse-width modulated by the emission control gate driver circuits in the gate driver circuitry to control the output of the light-emitting diodes. The emission control gate driver circuits may be controlled using an emission start signal and a pair of two-phase clocks.
Abstract:
An organic light-emitting diode display may have an array of pixel circuits. Each pixel circuit may contain an organic light-emitting diode that emits light, a drive transistor that controls current flow through the diode, and additional transistors such as switching transistors for loading data into the pixel circuit and emission transistors for enabling and disabling current flow through the drive transistor and diode. Gate driver circuitry may produce emission control signals that control the emission transistors. Display driver circuitry may generate a start signal with a digitally controlled pulse width. The start signal may be applied to shift register circuitry in the gate driver circuitry. The pulse width of the start signal may be adjusted to adjust the luminance of the display.
Abstract:
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.
Abstract:
An electronic device may have a display such as an organic light-emitting diode display. The organic light-emitting diode (OLED) display may have an array of organic light-emitting diode pixels that each have OLED layers interposed between a cathode and an anode. A first passivation layer, a first planarization layer, and a second passivation layer may be formed over the cathode. The first and second passivation layers may be formed from inorganic material. A second planarization layer may be formed over the second passivation layer between the second passivation layer and a polarizer. The second planarization layer may planarize the polarizer at the edges of the active area of the display where the polarizer would otherwise have a steep taper. Planarizing the polarizer in this way mitigates undesirable secondary reflections off of the polarizer. The first and second planarization layers may be formed from organic material.