Abstract:
A thin-film transistor having a protection layer for a planarization layer. The protection layer prevents reduction of the planarization layer during an ashing process, thereby preventing the formation of a steeply tapered via hole through the planarization layer. In this manner, the via hole may be coated with a conductive element that may serve as a conductive path between a common electrode and the drain of the transistor.
Abstract:
An electronic display for providing a visual or video output for an electronic device. The electronic device includes a transistor layer configured to activate a first pixel row and a second pixel row. For each pixel in the first pixel row and the second pixel row, the transistor layer includes a switch transistor, a pixel electrode, and a common electrode. The electronic device further includes a pixel controller for selectively activating each pixel. The pixel controller includes a first gate line, a first drive line, and a second drive line. During operation, the first gate line provides a charge to the pixel electrode for a first pixel in the first pixel row and for a second pixel in the second pixel row, and the first drive line activates the switch transistor for the first pixel, and the second drive line activates the switch transistor for the second pixel.
Abstract:
An electronic device may have a display with touch sensors. One or more shielding layers may be interposed between the display and the touch sensors. The shielding layers may include shielding structures such as a conductive mesh structure and/or a transparent conductive film. The shielding structures may be actively driven or passively biased. In the active driving scheme, one or more inverting circuits may receive a noise signal from a cathode layer in the display and/or from the shielding structures, invert the received noise signal, and drive the inverted noise signal back onto the shielding structures to prevent any noise from the display from negatively impacting the performance of the touch sensors. In the passive biasing scheme, the shielding structures may be biased to a power supply voltage.
Abstract:
A pixel array may be illuminated with backlight illumination from a backlight. The backlight may include a two-dimensional array of light-emitting diodes, with each light-emitting diode being placed in a respective cell. Different light-emitting diodes may have unique brightness magnitudes based on the content of the given display frame. Driver integrated circuits may control one or more associated light-emitting diodes to have a desired brightness level. The driver integrated circuits may be formed in an active area of the backlight. The driver integrated circuits may be arranged in groups that are daisy chained together. A digital signal (that includes information such as addressing information) may be propagated through the group of driver integrated circuits. To manage thermal performance of the backlight, the backlight may include a thermally conductive layer and/or a heat sink structure. To increase the efficiency of the backlight, the backlight may include one or more reflective layers.
Abstract:
An electronic device may have a housing and a display in the housing. The display may have one or more curved edges such as curved edges associated with rounded corners in the display and housing. The display may have an array of pixels. The display may include full-strength pixels and may have a band of antialiasing pixels having selectively reduced strengths to visually smooth content displayed along the curved edges. The pixels may be organic light-emitting diode pixels, liquid crystal display pixels, or other display pixels. Organic light-emitting diode pixels may have drive transistors and associated organic light-emitting diodes. Selectively elevated series or opaque light blocking structures of selectively reduced areas may be used to selectively reduce the strength of the antialiasing pixels. Liquid crystal display pixels may include electrodes of different shapes and/or opaque layer openings of different sizes to form antialiasing pixels in desired patterns.
Abstract:
A display is provided that includes an array of display pixels and gate driver circuitry for providing data and gate line signals to the display pixels. Gate driver circuitry may include gate driver circuits that generate the gate line signals. A gate driver circuit may include at least a buffer transistor, a bootstrapping capacitor coupled to the buffer transistor, a pulldown transistor coupled in series with the buffer transistor, and an isolation transistor coupled to the gate of the pulldown transistor. The buffer transistor may directly receive a first clock signal, whereas the isolation transistor may directly receive a second clock signal that is complementary to the first clock signal. The pulldown transistor is substantially larger than the buffer transistor. The buffer transistor is substantially larger than the isolation transistor. Configured as such, clock loading is minimized while the pulldown transistor is sized to provide the desired fall time performance.
Abstract:
A display may have a first stage such as a color liquid crystal display stage and a second stage such as a monochromatic liquid crystal display stage that are coupled in tandem so that light from a backlight passes through both stages. The first (upper) stage may be a high resolution display panel that is operated at a first refresh rate while the second (lower) stage is a low resolution display panel that is operated at a second refresh rate that is greater than the first refresh rate. In particular, the second stage may be configured to provide localized dimming that is synchronized to one or more moving objects in the video frames to be displayed to help reduce the perceived motion blur. The localized dimming may be provided via insertion of a black image portion that only overlaps with the moving objects, a blanking row that tracks the moving objects, a black frame, etc.
Abstract:
A display may have an array of pixels arranged in rows and columns. Each pixel may have a transistor for controlling the amount of output light associated with that pixel. The transistors may be thin-film transistors having active areas, first and second source-drain terminals, and gates. Gate lines may be used to distribute gate control signals to the gates of the transistors in each row. Data lines that run perpendicular to the gate lines may be used to distribute image data along columns of pixels. The gate lines may be connected to gate line extensions that run parallel to the data lines. The data lines may each overlap a respective one of the gate line extensions. Vias may be used to connect the gate line extensions to the gate lines. The gate line extensions may all have the same length.
Abstract:
A display is provided that includes an array of display pixels and gate driver circuitry for providing data and gate line signals to the display pixels. Gate driver circuitry may include gate driver circuits that generate the gate line signals. A gate driver circuit may include at least a buffer transistor, a bootstrapping capacitor coupled to the buffer transistor, a pulldown transistor coupled in series with the buffer transistor, and an isolation transistor coupled to the gate of the pulldown transistor. The buffer transistor may directly receive a first clock signal, whereas the isolation transistor may directly receive a second clock signal that is complementary to the first clock signal. The pulldown transistor is substantially larger than the buffer transistor. The buffer transistor is substantially larger than the isolation transistor. Configured as such, clock loading is minimized while the pulldown transistor is sized to provide the desired fall time performance.
Abstract:
A display may have upper and lower display layers. A layer of liquid crystal material may be interposed between the upper and lower display layers. The display layers may have substrates. The display layers may include a color filter layer having an array of color filter elements on a glass substrate and a thin-film transistor layer having a layer of thin-film transistor circuitry on a glass substrate. Dielectric layers within the display layers such as dielectric layers within the thin-film transistor layer may have differing indices of refraction. Reflections and color shifts due to index of refraction discontinuities may be minimized by interposing graded index dielectric layers between adjacent layers with different indices. The graded index layers may be formed from structures with a continuously varying index of refraction or structures with a step-wise varying index of refraction.