Abstract: A display may include an array of pixels that receive control signals from a chain of gate drivers. Each gate driver may include a logic sub-circuit and an output buffer sub-circuit. The output buffer sub-circuit may include depletion mode semiconducting oxide transistors with high mobility. The logic sub-circuit may include semiconducting oxide transistors, some of which can be depletion mode transistors and some of which can be enhancement mode transistors with lower mobility. The logic sub-circuit may include at least a carry circuit, a voltage setting circuit, an inverting circuit, a discharge circuit.

Abstract: A display may include an array of pixels. Each pixel in the array includes an organic light-emitting diode coupled to a drive transistor, a data loading transistor, a first capacitor for storing data charge, and a second capacitor. During a data programming phase, the data loading transistor may be activated to load in a data value onto the first capacitor. After the data programming phase, the second capacitor may be configured to receive a lower voltage, which extends a threshold voltage sampling time for the pixel. Configured and operated in this way, the temperature luminance sensitivity of the display can be reduced.

Abstract: A display may have an array of pixels. Each pixel may have a light-emitting diode such as an organic light-emitting diode. The organic light-emitting diodes may each have an anode that is coupled to a thin-film transistor pixel circuit for controlling the anode. Transparent windows may be formed in the display. The windows may be formed by replacing data storage capacitors and other pixel circuit structures in a subset of the pixels with transparent window structures, by selectively removing portions of light-emitting diode anodes, and by shifting anodes. An array of electrical components such as an array of light sensors may be aligned with the transparent windows and may be used to measure light passing through the transparent windows.

Abstract: A display may have an array of pixels each of which has a light-emitting diode such as an organic light-emitting diode. A drive transistor and an emission transistor may be coupled in series with the light-emitting diode of each pixel between a positive power supply and a ground power supply. The pixels may include first and second switching transistors. A data storage capacitor may be coupled between a gate and source of the drive transistor in each pixel. Signal lines may be provided in columns of pixels to route signals such as data signals, sensed drive currents from the drive transistors, and predetermined voltages between display driver circuitry and the pixels. The switching transistors, emission transistors, and drive transistors may include semiconducting-oxide transistors and silicon transistors and may be n-channel transistors or p-channel transistors.

Abstract: A display may include an array of pixels. Each pixel in the array may include a drive transistor, emission transistors, a data loading transistor, a gate voltage setting transistor, an initialization transistor, an anode reset transistor, a storage capacitor, and an optional current boosting capacitor. A data refresh may include a initialization phase, a threshold voltage sampling phase, and a data programming phase. The threshold voltage sampling phase can be substantially longer than the data programming phase to decrease a current sampling level during the threshold voltage sampling phase, which helps reduce the display luminance sensitivity to temperature variations.

Abstract: A display is provided that includes an array of display pixels that receive data signals from display driver circuitry and that receive control signals from gate driver circuitry. The gate driver circuitry may include a chain of row driver circuits. Each row driver circuit may include a scan driver circuit and a scan inverter circuit. An enable transistor may be interposed between the scan driver circuit and the scan inverter circuit and may be selectively disabled to decouple the scan inverter circuit from the scan driver circuit to allow the scan inverter circuit to operate independent from the scan driver circuit. The scan inverter circuit may include a transistor that receives a scan pulse signal from the scan driver circuit and may further include additional transistors connected in a negative feedback configuration to reduce a drain-to-source voltage across the transistor to reduce leakage across the transistor during blanking times.

Abstract: A display may have an array of pixels each of which has a light-emitting diode such as an organic light-emitting diode. A drive transistor and an emission transistor may be coupled in series with the light-emitting diode of each pixel between a positive power supply and a ground power supply. The pixels may include first and second switching transistors. A data storage capacitor may be coupled between a gate and source of the drive transistor in each pixel. Signal lines may be provided in columns of pixels to route signals such as data signals, sensed drive currents from the drive transistors, and predetermined voltages between display driver circuitry and the pixels. The switching transistors, emission transistors, and drive transistors may include semiconducting-oxide transistors and silicon transistors and may be n-channel transistors or p-channel transistors.

Abstract: An electronic device may include a display with pixels formed using light-emitting diodes, thin-film silicon transistors, thin-film semiconducting-oxide transistors, and capacitors. The silicon transistors, semiconducting-transistors, and capacitors may have control terminals that are coupled to gate or routing lines that extend across the face of the display and that are formed in a low resistance source-drain metal routing layer. Forming routing/gate lines using the low resistance source-drain metal routing layer dramatically reduces the resistance of the gate lines, which enables better timing margins for large display panels operating at higher refresh rates.

Abstract: A display may include an array of pixels. Each pixel in the array may include a drive transistor, emission transistors, a data loading transistor, a gate voltage setting transistor, an initialization transistor, an anode reset transistor, a storage capacitor, and an optional current boosting capacitor. A data refresh may include a initialization phase, a threshold voltage sampling phase, and a data programming phase. The threshold voltage sampling phase can be substantially longer than the data programming phase to decrease a current sampling level during the threshold voltage sampling phase, which helps reduce the display luminance sensitivity to temperature variations.

Abstract: A display may have an array of pixels. Each pixel may have a light-emitting diode such as an organic light-emitting diode. The organic light-emitting diodes may each have an anode that is coupled to a thin-film transistor pixel circuit for controlling the anode. Transparent windows may be formed in the display. The windows may be formed by replacing data storage capacitors and other pixel circuit structures in a subset of the pixels with transparent window structures, by selectively removing portions of light-emitting diode anodes, and by shifting anodes. An array of electrical components such as an array of light sensors may be aligned with the transparent windows and may be used to measure light passing through the transparent windows.

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: Electronic devices and methods for compensating for aging or other effects in a display during a non-transmitting state (off state) of the display. Sensing may include emissive element sensing of the display and/or thin film transistor sensing of the display. Compensating for the effects may preserve or increase a uniformity of transmission of the display.

Abstract: An electronic device comprises a controller. The controller is configured to provide a first signal to a display of the electronic device to turn off the display. The controller is also configured to provide a second signal to the display to alter a gate source voltage of a drive transistor coupled to a light emitting diode (LED) of a pixel of the display while the display is turned off.

Abstract: A display may include an array of pixels. Each pixel in the array includes an organic light-emitting diode coupled to a drive transistor, a data loading transistor, a first capacitor for storing data charge, and a second capacitor. During a data programming phase, the data loading transistor may be activated to load in a data value onto the first capacitor. After the data programming phase, the second capacitor may be configured to receive a lower voltage, which extends a threshold voltage sampling time for the pixel. Configured and operated in this way, the temperature luminance sensitivity of the display can be reduced.

Abstract: A display may include an array of pixels. Each pixel in the array includes an organic light-emitting diode coupled to associated semiconducting oxide transistors. The semiconducting oxide transistors may exhibit different device characteristics. Some of the semiconducting oxide transistors may be formed using a first oxide layer formed from a first semiconducting oxide material using first processing steps, whereas other semiconducting oxide transistors are formed using a second oxide layer formed from a second semiconducting oxide material using second processing steps different than the first processing steps. The display may include three or more different semiconducting oxide layers formed during different processing steps.

Abstract: A display pixel is provided that is operable to support hybrid compensation scheme having both in-pixel threshold voltage canceling and external threshold voltage compensation. The display may include multiple p-type silicon transistors with at least one n-type semiconducting-oxide transistor and one storage capacitor. An on-bias stress phase may be performed prior to a threshold voltage sampling and data programming phase to mitigate hysteresis and improve first frame response. In low refresh rate displays, a first additional on-bias stress operation can be performed separate from the threshold voltage sampling and data programming phase during a refresh frame and a second additional on-bias stress operation can be performed during a vertical blanking frame. The display pixel may be configured to receive an initialization voltage and an anode reset voltage, either of which can be dynamically tuned to match the stress of the first and second additional on-bias stress operations to minimize flicker.

Abstract: A display may include an array of pixels, where each pixel in the array includes an organic light-emitting diode coupled to associated thin-film transistors. The thin-film transistors may be controlled using at least first and second horizontal scan line signals. Loading different data values into any given row in the array may cause the scan line signals to exhibit varying rise/fall times, which results in horizontal crosstalk and luminance non-uniformity across the display. The rise and fall times of the second scan line signal are crucial, so the second scan line signal is driven by two separate scan line drivers formed on both sides of the display. Only the fall time of the first scan line signal is crucial, so the first scan line signal is driven by only one peripheral scan line driver and is coupled to an auxiliary pull-down circuit that is only activated during the pull-down transition.

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: 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.

Abstract: An electronic device may include a display having an array of display pixels on a substrate. The display pixels may be organic light-emitting diode display pixels, that include hybrid thin-film transistor structures formed using semiconducting-oxide thin-film transistors, silicon thin-film transistors, and capacitor structures. A drive transistor in the display pixel may be a top-gate semiconducting-oxide thin-film transistor and a switching transistor in the display pixel may be a top-gate silicon thin-film transistor. A storage capacitor in the display may include a conductive semiconducting-oxide electrode.