Driver Circuitry for Displays

• US 20130063404A1
• Filed: 09/13/2011
• Published: 03/14/2013
• Est. Priority Date: 09/13/2011
• Status: Abandoned Application

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Jamshidi Roudbari, Abbas, Chang, Shih-Chang
• Application Number:
  US13/231,841
• Publication Number:
  US 20130063404A1
• Time in Patent Office: Days
• US Class Current: 345/204
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2310/0267 Details of drivers for scan electrodes, other than drivers for liquid crystal, plasma or OLED displays
• CPC Class Codes: G09G 2310/0297 Special arrangements with multiplexing or demultiplexing of display data in the drivers for data electrodes, in a pre-processing circuitry delivering display data to said drivers or in the matrix panel, e.g. multiplexing plural data signals to one D/A converter or demultiplexing the D/A converter output to multiple columns
• CPC Class Codes: G09G 2320/0219 Reducing feedthrough effects in active matrix panels, i.e. voltage changes on the scan electrode influencing the pixel voltage due to capacitive coupling
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/0693 Calibration of display systems
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 3/3677 suitable for active matrices only

Abstract

An electronic device display may have an array of display pixels. Each pixel may receive display data on a data line and may have a thin-film transistor that is controlled by a gate line signal on a gate line. The transistors may be controlled to apply electric fields across liquid crystal material. A common electrode may be used to distribute common electrode signals to the display pixels. The display may have a segmented common electrode with isolated regions that serve as respective touch sensor electrodes. A display may include a display driver integrated circuit that is adjusted to produce clock signals with desired rise and fall times. Gate driver circuitry such as thin-film transistor circuitry may include pass transistors controlled by latches. The pass transistors may be used in providing the clock signals with the adjusted rise and fall times to the gate lines to serve as gate line signals.

Claims

1. Driver circuitry for producing gate line signals that are applied to gate lines in a display, the driver circuitry comprising:

at least one clock path configured to carry clock signals with adjustable transition times;

a plurality of latches; and

a plurality of output circuits that receive the clock signals with adjustable transition times from the at least one clock path and that receive signals from the latches, wherein the plurality of latches and output circuits are organized in a plurality of rows and wherein the output circuit in each row supplies a received clock signal to a gate line in that row to serve as a gate line signal for that row.

2. The driver circuitry defined in claim 1 further comprising an adjustable display driver circuit configured to supply the clock signals with the adjustable transition times to the at least one clock path.

3. The driver circuitry defined in claim 1 wherein the output circuit in each row includes a pass gate.

4. The driver circuitry defined in claim 3 wherein the pass gate in each row has input configured to receive the clock signal that serves as the gate line signal in that row from the at least one clock path.

5. The driver circuitry defined in claim 4 wherein the pass gate in each row has an output coupled to the gate line in that row.

6. The driver circuitry defined in claim 5 wherein the pass gate in each row includes at least one metal-oxide-semiconductor transistor.

7. The driver circuitry defined in claim 5 wherein the pass gate in each row includes an n-channel metal-oxide-semiconductor transistor and a p-channel metal-oxide-semiconductor transistor.

8. The driver circuitry defined in claim 7 further comprising an additional n-channel metal-oxide-semiconductor transistor in each row that is coupled to the gate line.

9. The driver circuitry defined in claim 5 wherein the latch in each row has true and complement outputs and wherein the true output is coupled to a first transistor gate in the pass gate and wherein the complement output is coupled to a second transistor gate in the pass gate.

10. The driver circuitry defined in claim 9 wherein the pass gate includes an n-channel metal-oxide-semiconductor transistor and wherein the first transistor gate is a gate of the n-channel metal-oxide-semiconductor transistor.

11. The driver circuitry defined in claim 10 wherein the pass gate includes a p-channel metal-oxide-semiconductor transistor and wherein the second transistor gate is a gate of the p-channel metal-oxide-semiconductor transistor.

12. The driver circuitry defined in claim 11 wherein the true output of the latch in each row is coupled to a data input of the latch in a successive row.

13. The driver circuitry defined in claim 12 wherein the output circuit of each row includes an additional n-channel transistor that is coupled to the gate line in that row and that has a transistor gate and wherein the complement output in that row is coupled to the transistor gate.

14. The driver circuitry defined in claim 13 further comprising an adjustable display driver integrated circuit configured to supply the clock signals with the adjustable transition times to the at least one clock path, wherein the adjustable transition times include an adjustable clock signal rise time and an adjustable clock signal fall time.

15. A method, comprising:

with a display driver circuit in a display, receiving settings that adjust a clock signal transition time;

with the display driver circuit, providing clock signals with the adjusted clock signal transition time from the display driver circuit to gate driver circuitry; and

with the gate driver circuitry, using the clock signals with the adjusted clock signal transition time to produce gate line signals for the display that have the adjusted clock signal transition time.

16. The method defined in claim 15 wherein the display driver circuit comprises a display driver integrated circuit and wherein the gate driver circuitry comprises polysilicon transistors on a thin-film transistor substrate layer and wherein providing the clock signals with the adjusted clock signal transition time comprises supplying the clock signals with the adjusted clock signal transition time from the display driver integrated circuit to the polysilicon transistors.

17. The method defined in claim 16 further comprising:

inspecting the display for visual artifacts from common electrode signal perturbations; and

based on results from inspecting the display, adjusting the settings.

18. A display, comprising:

an array of display pixels configured to receive display image data on data lines and having thin-film transistors controlled by gate line signals on gate lines; and

display driver circuitry that produces clock signals with adjustable rise and fall times; and

gate driver circuitry that receives the clock signals from the display driver circuitry and provides them to the gate lines to serve as the gate line signals.

19. The display defined in claim 18 wherein the gate driver circuitry comprises pass gates, wherein each pass gate provides a respective one of the clock signals to a respective one of the gate lines.

20. The display defined in claim 19 wherein the gate driver circuitry comprises latches that provide control signals to the pass gates.

21. The display defined in claim 20 further comprising a common electrode conductor for distributing common electrode signals to the display pixels, wherein the common electrode is segmented to form multiple isolated regions of common electrode conductor that serve as respective touch sensor electrodes.

22. The display defined in claim 20 wherein the latches each comprise a plurality of latch transistors including a first latch transistor having a first gate and a second latch transistor having a second gate, each latch further comprising a third transistor having a third gate that receives a given one of the clock signals and a fourth transistor having a fourth gate that receives that given one of the clock signals, wherein the third transistor has source-drain terminals coupled between a positive power supply terminal and the first gate, and wherein the fourth transistor has source-drain terminals coupled between a ground power supply terminal and the second gate.