Abstract:
Systems and electronic displays with improved contrast even under bright-light conditions are provided. Such an electronic display may include a self-emissive pixel (e.g., OLED or μ-LED) with a corresponding liquid crystal switchable retarder pixel. A liquid crystal layer of the switchable retarder pixel may be tuned to an “on” state or an “off” state. In the “on” state, the switchable retarder pixel may allow outside light that enters the pixel to reflect back out of the pixel. This may add to the amount of light that appears to be emitted from that pixel. In the “off” state, the switchable retarder pixel may block the outside light that enters the pixel from reflecting back out of the pixel. This may reduce the amount of light that appears to be emitted from that pixel. Selectively controlling the switchable retarder pixels may allow for increased contrast even under bright-light conditions.
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 and cathode. 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 and switching transistors. 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 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:
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:
This application sets forth a circuit configuration for a light emitting diode (LED) or organic light emitting diode (OLED) display. The circuit configuration allows for the pulse-width modulation (PWM) of each emission signal sent to each line of the display. The PWM of each emission signal is accomplished using a gate-in-panel (GIP) controller of the display. The GIP controller uses an arrangement of shift register outputs and a programmable clock input to control an output of an inverter that provides the emission signal. The programmable clock input can be programmed according to a desired timing or duty cycle for the emission signal. In this way, by limiting the duty cycle of the emission signal, dimming and other display features can be exhibited by the LED or OLED display.
Abstract:
An electronic device may include a display. The display may be formed by an array of light-emitting diodes mounted to the surface of a substrate. The light-emitting diodes may be inorganic light-emitting diodes formed from separate crystalline semiconductor structures. An array of pixel control circuits may be used to control light emission from the light-emitting diodes. Each pixel control circuit may be used to supply drive signals to a respective set of the light-emitting diodes. The pixel control circuits may each have a silicon integrated circuit that includes transistors such as emission enable transistors and drive transistors for supplying the drive signals and may each have thin-film semiconducting oxide transistors that are coupled to the integrated circuit and that serve as switching transistors.
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. Display driver circuitry may simultaneously compensate multiple rows of the display pixels for drive transistor threshold voltage variations by supplying a common reference voltage over the data lines during a common compensation period. The display data may then be loaded into the rows sequentially before simultaneously commencing emission in each of the compensated and programmed rows.
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 electronic device comprises a display and a controller. The controller is configured to provide a first frequency refresh rate to the display. The controller is also configured to generate a control signal configured to control emission of a light emitting diode of a display pixel of the display at a second frequency based on whether the first frequency refresh rate of the display is less than a predetermined threshold value.
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 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.