Abstract: An organic light-emitting diode display may have thin-film transistor circuitry formed on a substrate. The display and substrate may have rounded corners. A pixel definition layer may be formed on the thin-film transistor circuitry. Openings in the pixel definition layer may be provided with emissive material overlapping respective anodes for organic light-emitting diodes. A cathode layer may cover the array of pixels. A ground power supply path may be used to distribute a ground voltage to the cathode layer. The ground power supply path may be formed from a metal layer that is shorted to the cathode layer using portions of a metal layer that forms anodes for the diodes, may be formed from a mesh shaped metal pattern, may have L-shaped path segments, may include laser-deposited metal on the cathode layer, and may have other structures that facilitate distribution of the ground power supply.

Abstract: An organic light-emitting diode display may contain an array of display pixels. Each display pixel may have a respective organic light-emitting diode that is controlled by a drive transistor. At low temperatures, it may be necessary to increase the amount of current through an organic light-emitting diode to achieve a desired luminance level. In order to increase the current through the light-emitting diode, the ground voltage level may be lowered. However, this may lead to thin-film transistors within the pixel leaking, which may result in undesirable display artifacts such as bright dots being displayed in a dark image. In order to prevent leakage in the transistors, the transistors may be coupled to separate reference voltage supplies or separate control lines. Additionally, the transistors may be positioned to minimize leakage even at low ground voltage levels.

Abstract: A display may have an array of pixels. Display driver circuitry may supply data and control signals to the pixels. Each pixel may have seven transistors, a capacitor, and a light-emitting diode such as an organic light-emitting diode. The seven transistors may receive control signals using horizontal control lines. Each pixel may have first and second emission enable transistors that are coupled in series with a drive transistor and the light-emitting diode of that pixel. The first and second emission enable transistors may be coupled to a common control line or may be separately controlled so that on-bias stress can be effectively applied to the drive transistor. The display driver circuitry may have gate driver circuits that provide different gate line signals to different rows of pixels within the display. Different rows may also have different gate driver strengths and different supplemental gate line loading structures.

Abstract: A display may have rows and columns of pixels. Gate lines may be used to supply gate signals to rows of the pixels. Data lines may be used to supply data signals to columns of the pixels. The data lines may include alternating even and odd data lines. Data lines may be organized in pairs each of which includes one of the odd data lines and an adjacent one of the even data lines. Demultiplexer circuitry may be configured dynamically during data loading and pixel sensing operations. During data loading, data from display driver circuitry may be supplied, alternately to odd pairs of the data lines and even pairs of the data lines. During sensing, the demultiplexer circuitry may couple a pair of the even data lines to sensing circuitry in the display driver circuitry and then may couple a pair of the odd data lines to the sensing circuitry.

Abstract: A display may have an active area that includes display pixels. The display may include an inactive notch region that extends into the active area. Data lines may provide image data from display driver circuitry to the display pixels. The image data may include data signals that correspond to portions of the display that do not include pixels, such as the inactive notch region. The null data signals may cause nonuniformities in the displayed image. The null data signals may be adjusted to minimize the nonuniformities. Null data signals corresponding to the inactive notch region may be adjusted to have gray levels that gradually decrease with distance from the border between the inactive notch and the active area. All of the data signals corresponding to the inactive notch may be set to a uniform gray level.

Abstract: An organic light-emitting diode display may have an array of pixels. The pixels may each have an organic light-emitting diode with a respective anode and may be formed from thin-film transistor circuitry formed on a substrate. A mesh-shaped path may be used to distribute a power supply voltage to the thin-film circuitry. The mesh-shaped path may have intersecting horizontally extending lines and vertically extending lines. The horizontally extending lines may be zigzag metal lines that do not overlap the anodes. The vertically extending lines may be straight vertical metal lines that overlap the anodes. The pixels may include pixels of different colors. Angularly dependent shifts in display color may be minimized by ensuring that the anodes of the differently colored pixels overlap the vertically extending lines by similar amounts.

Abstract: A display may have rows and columns of pixels that form an active area for displaying images. A display driver integrated circuit may provide multiplexed data signals to demultiplexer circuitry in the display. The demultiplexer circuitry may demultiplex the data signals and provide the demultiplexed data signals to the pixels on data lines. Gate lines may control the loading of the data signals into the pixels. The display may have a length dimension and a width dimension that is shorter than the length dimension. The data lines may extend parallel to the width dimension and the gate lines may extend parallel to the length dimension such that there are more data lines than gate lines in the display. A notch that is free of pixels may extend into the active area. Data lines extending parallel to the width dimension of the display may be routed around the notch.

Abstract: A display may have an array of pixels. Display driver circuitry may supply data and control signals to the pixels. Each pixel may have seven transistors, a capacitor, and a light-emitting diode such as an organic light-emitting diode. The seven transistors may receive control signals using horizontal control lines. Each pixel may have first and second emission enable transistors that are coupled in series with a drive transistor and the light-emitting diode of that pixel. The first and second emission enable transistors may be coupled to a common control line or may be separately controlled so that on-bias stress can be effectively applied to the drive transistor. The display driver circuitry may have gate driver circuits that provide different gate line signals to different rows of pixels within the display. Different rows may also have different gate driver strengths and different supplemental gate line loading structures.

Abstract: Electronic devices, storage medium containing instructions, and methods pertain to cancelling noise that results from application of clocks/clock drivers of a display. The electronic display may inject counter noise into the cathode. For example, the counter noise may be injected via a sensing layer, via unused clocks, and/or via a power rail of the display.

Abstract: Aspects of the subject technology relate to display circuitry. The display circuitry includes gate-in-panel (GIP) control circuitry on opposing sides of a display pixel array. The GIP control circuitry can include scan drivers for each pixel row on both sides of that pixel row, the scan drivers on either side configured for enablement or disablement for single-sided reduced-power operations. The GIP control circuitry can include a single scan driver and a single emission controller for each pixel row, in which the scan driver and emission controller for each row are disposed on opposing sides of the row. The scan drivers for a first subset of the pixel rows can be interleaved with the emission controllers for a different subset of the pixel rows.

Abstract: Electronic devices, storage medium containing instructions, and methods pertain to cancelling noise that results from application of voltages on gates of transistors in a display. One or more compensation or dummy drivers are used to apply a compensation voltage that is an inversion of voltages applied on the gates of the transistors.

Abstract: A display may have an array of pixels. Display driver circuitry may supply data and control signals to the pixels. Each pixel may have seven transistors, a capacitor, and a light-emitting diode such as an organic light-emitting diode. The seven transistors may receive control signals using horizontal control lines. Each pixel may have first and second emission enable transistors that are coupled in series with a drive transistor and the light-emitting diode of that pixel. The first and second emission enable transistors may be coupled to a common control line or may be separately controlled so that on-bias stress can be effectively applied to the drive transistor. The display driver circuitry may have gate driver circuits that provide different gate line signals to different rows of pixels within the display. Different rows may also have different gate driver strengths and different supplemental gate line loading structures.

Abstract: An organic light-emitting diode display may have thin-film transistor circuitry formed on a substrate. The display and substrate may have rounded corners. A pixel definition layer may be formed on the thin-film transistor circuitry. Openings in the pixel definition layer may be provided with emissive material overlapping respective anodes for organic light-emitting diodes. A cathode layer may cover the array of pixels. A ground power supply path may be used to distribute a ground voltage to the cathode layer. The ground power supply path may be formed from a metal layer that is shorted to the cathode layer using portions of a metal layer that forms anodes for the diodes, may be formed from a mesh shaped metal pattern, may have L-shaped path segments, may include laser-deposited metal on the cathode layer, and may have other structures that facilitate distribution of the ground power supply.

Abstract: An organic light-emitting diode display may have an array of pixels. The pixels may each have an organic light-emitting diode with a respective anode and may be formed from thin-film transistor circuitry formed on a substrate. A mesh-shaped path may be used to distribute a power supply voltage to the thin-film circuitry. The mesh-shaped path may have intersecting horizontally extending lines and vertically extending lines. The horizontally extending lines may be zigzag metal lines that do not overlap the anodes. The vertically extending lines may be straight vertical metal lines that overlap the anodes. The pixels may include pixels of different colors. Angularly dependent shifts in display color may be minimized by ensuring that the anodes of the differently colored pixels overlap the vertically extending lines by similar amounts.

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: An organic light-emitting diode display may contain an array of display pixels. Each display pixel may have a respective organic light-emitting diode that is controlled by a drive transistor. At low temperatures, it may be necessary to increase the amount of current through an organic light-emitting diode to achieve a desired luminance level. In order to increase the current through the light-emitting diode, the ground voltage level may be lowered. However, this may lead to thin-film transistors within the pixel leaking, which may result in undesirable display artifacts such as bright dots being displayed in a dark image. In order to prevent leakage in the transistors, the transistors may be coupled to separate reference voltage supplies or separate control lines. Additionally, the transistors may be positioned to minimize leakage even at low ground voltage levels.

Abstract: A display having thin-film transistor (TFT) structures may be used to display images within an active area of the display, which is surrounded by an inactive border area. In order to reduce the inactive area, a TFT passivation layer may be used to help protect conductive routing lines at the outer edge of the border so that encapsulation layers need not be formed all the way to the edge. At least some of the conductive routing lines in the inactive area may be stacked or coupled in parallel to help reduce border width. The TFT passivation layer may also cover the lateral edges of the routing lines to help prevent corrosion during an anode etch. The encapsulation layers may also be formed in a bent portion of the display substrate to help adjust the neutral stress plane such that metal traces formed in the bent portion do not crack.

Abstract: A display having thin-film transistor (TFT) structures may be used to display images within an active area of the display, which is surrounded by an inactive border area. In order to reduce the inactive area, a TFT passivation layer may be used to help protect conductive routing lines at the outer edge of the border so that encapsulation layers need not be formed all the way to the edge. At least some of the conductive routing lines in the inactive area may be stacked or coupled in parallel to help reduce border width. The TFT passivation layer may also cover the lateral edges of the routing lines to help prevent corrosion during an anode etch. The encapsulation layers may also be formed in a bent portion of the display substrate to help adjust the neutral stress plane such that metal traces formed in the bent portion do not crack.

Abstract: A method for forming contacts on a photovoltaic device includes forming a heterojunction cell including a substrate, a passivation layer and a doped layer and forming a transparent conductor on the cell. A patterned barrier layer is formed on the transparent conductor and has openings therein wherein the transparent conductor is exposed through the openings in the barrier layer. A conductive contact is grown through the openings in the patterned barrier layer by a selective plating process.

Abstract: A method for forming contacts on a photovoltaic device includes forming a heterojunction cell including a substrate, a passivation layer and a doped layer and forming a transparent conductor on the cell. A patterned barrier layer is formed on the transparent conductor and has openings therein wherein the transparent conductor is exposed through the openings in the barrier layer. A conductive contact is grown through the openings in the patterned barrier layer by a selective plating process.