Low complexity gate line driver circuitry

• US 9,317,151 B2
• Filed: 01/23/2013
• Issued: 04/19/2016
• Est. Priority Date: 05/14/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Jamshidi-Roudbari, Abbas, Yu, Cheng-Ho, Chang, Shih Chang, Chang, Ting-Kuo
• Primary Examiner(s): LAMB, CHRISTOPHER RAY
• Application Number:
  US13/747,872
• Publication Number:
  US 20130300681A1
• Time in Patent Office: 1,182 Days
• Field of Search: None
• US Class Current: 1/1
• 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 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

Abstract

Gate driver circuitry that controls an array of display elements is described. The gate driver circuitry has gate drivers that apply a control pulse to each of a number of gate lines in sequence, from a previous gate line to a current gate line, during a frame interval in which the array of display elements is filled with pixel values. Each gate driver has a latch stage followed by an output stage. The output stage is coupled to drive a current gate line, and the latch stage is coupled to drive a) a first hold circuit that holds the current gate line at a predetermined voltage, and b) a second hold circuit that holds a previous gate line at a predetermined voltage. Other embodiments are also described and claimed.

Claims

1. An electronic device comprising:

a plurality of gate lines; and

a plurality of gate drivers each having a latch stage followed by an output stage, the output stage being coupled to drive a current gate line, and wherein the gate driver is coupled to drive a) a first hold circuit that holds the current gate line at a predetermined voltage, and b) a second hold circuit that holds a previous gate line at a predetermined voltage, and wherein each gate driver further comprises another output stage that is controlled by the latch stage and is coupled to drive another gate line.

2. The electronic device of claim 1 further comprising a plurality of display elements arranged as an array, and the gate drivers are arranged a) from top to bottom of the array in sequential scan order and b) alternating between left and right of the array.

3. The electronic device of claim 2 further comprising:

a touch transducer that overlays the display element array; and

a touch controller to generate a stimulation or sensing signal in the touch transducer.

4. The electronic device of claim 2 further comprising a light passing substrate on which the array of display elements, the gate lines and the gate line driver circuitry are formed.

5. The electronic device of any claim 1 wherein constituent transistors of the latch stage, the output stage and the first and second hold circuits are thin film transistors.

6. The electronic device of claim 1 wherein the output stage comprises a pull-up circuit that can hold the current gate line at a voltage that enables display elements coupled to the current gate line to be updated with new pixel values,

and wherein the first hold circuit can hold the current gate line at a voltage that enables the display elements that are coupled to the current gate line to essentially maintain existing pixel values.

7. The electronic device of claim 5 wherein each of the first and second hold circuits comprises a pull-down transistor that is larger than every one of the constituent transistors of the output stage and the latch stage.

8. An electronic device comprising:

a plurality of gate lines, with a respective near hold circuit and a respective far hold circuit coupled to each of the gate lines;

a first plurality of gate drivers each of the first plurality of gate drivers being coupled to drive an associated odd numbered one of the gate lines, when the gate lines are numbered sequentially; and

a second plurality of gate drivers each of the second plurality of gate drivers being coupled to drive an associated even numbered one of the gate lines,

wherein for each gate line, the respective near hold circuit is located closer to an associated gate driver, that is coupled to drive the gate line, than the respective far hold circuit,

and wherein each of the gate drivers is further coupled to control a) the respective near hold circuit of an associated gate line and b) the respective far hold circuit of a neighbor gate line, and wherein each of the second plurality of gate drivers has two output stages that are controlled by the same latch stage and that are coupled to drive a respective pair of the associated even numbered gate lines.

9. The device of claim 8 wherein each of the first plurality of gate drivers has a latch stage with inverting and non-inverting outputs, and an output stage that is coupled to drive the associated gate line,

wherein the inverting output of the latch stage is directly connected to drive the respective near hold circuit of the associated gate line and the respective far hold circuit of the neighbor gate line.

10. The device of claim 9 wherein the output stage in each of the first plurality of gate drivers comprises a hold circuit that can hold the associated gate line at a voltage that enables display elements that are coupled to the associated gate line to be updated with new pixel values,

and wherein the respective near hold circuit can hold the associated gate line at a voltage that enables the display elements that are coupled to the associated gate line to essentially maintain existing pixel values.

11. The device of claim 8 wherein the first plurality of gate drivers are arranged in a column on one side of the gate lines, and the second plurality of gate driers are arranged on another side of the gate lines.

12. The device of claim 8 wherein each of the first plurality of gate drivers has two output stages that are controlled by the same latch stage and that are coupled to drive a respective pair of the associated odd numbered gate lines.

13. An electronic device comprising:

a touchscreen system having

a plurality of display elements,

a touch transducer,

a plurality of gate lines coupled to the display elements,

a plurality of gate drivers each having a latch stage driving an output stage, the output stage being coupled to drive a current gate line, wherein each gate driver further comprises another output stage that is controlled by the latch stage and is coupled to drive another gate line, and the latch stage being coupled to drive a) a first hold circuit that holds the current gate line at a predetermined voltage, and b) a second hold circuit that holds a previous gate line at a predetermined voltage, and

controller circuitry that is coupled to the touch transducer and the gate drivers, the controller circuitry to generate a) a start pulse that is fed to one of the gate drivers and b) a plurality of clock signals that are fed to each of the gate drivers, when updating the display elements during a frame interval, the controller circuitry to read the touch transducer during a blanking interval in which the latch stage directly maintains gate electrodes of the first and second hold circuits at a fixed voltage without using a separate blanking control signal to directly control the gate electrodes, so as to hold the gate lines at the predetermined voltage.

14. The device of claim 13 wherein the latch stage has inverting and non-inverting outputs, the output stage being fed from the non-inverting output, and the inverting output is to drive the first hold circuit and the second hold circuit.