IP Library Granted Patent US 7,230,597
Granted Patent B2
US 7,230,597 · App. 10/191,293 · Granted Jun 12, 2007

Active matrix array devices

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Quick Facts
Patent No.
US 7,230,597
App. No.
10/191,293
Granted
Jun 12, 2007
Kind
B2
Abstract

An active matrix device includes a plurality of display elements 10 including a data storage node 18, 72 for storing data in the form of charge on a capacitor 72 and/or capacitative element 18 . Refresh circuitry 51 is provided to refresh the data storage node, for example including temporary storage circuit 55 and drive circuit 56.

Claims (41)

1. An active matrix device, comprising

an array of matrix elements wherein the matrix elements each have at least one storage node having a capacitance for storing data dynamically in the form of charge stored on the capacitance, and

the matrix elements further include refresh circuitry for refreshing the data stored on the storage node, wherein the refresh circuitry includes an inverter that is configured to selectively invert the data corresponding to the charges stored on the storage node.

2. The active matrix device of claim 1 , wherein the refresh circuitry includes

a temporary storage circuit for storing the data on the at least one storage node and

a storage node drive circuit for driving the storage node based on the data stored on the temporary storage circuit.

3. The active matrix device of claim 2 , wherein each matrix element includes:

an address switch controlled by an address line and connected between a column line and the at least one data storage node,

a storage switch connecting the storage node to the temporary storage circuit, and

a refresh switch connecting the storage node to the storage node drive circuit,

the storage switch and the refresh switch having control terminals connected to a common refresh line for switching between:

a first setting in which the storage switch is open and the refresh switch is closed, and

a second setting in which the storage switch is closed and the refresh switch is open.

4. The active matrix device of claim 3 , wherein the matrix elements each include a plurality of data storage capacitances for storing a plurality of bits of data per matrix element.

5. The active matrix device of claim 4 , including a plurality of row address lines controlling a plurality of address thin film transistors connected to respective data storage capacitances to select one or more of the data storage capacitances.

6. The active matrix device of claim 5 , wherein:

the plurality of address thin film transistors are connected to a common drive line connected through a select transistor to the column line, and

the select transistor is controlled by a select line.

7. The active matrix of claim 2 , wherein the temporary storage circuit and the storage node drive circuit are configured to be controlled by a single refresh signal.

8. The active matrix device of claim 1 , including a refresh line for activating the refresh circuitry to refresh the storage node.

9. The active matrix device of claim 1 , wherein the storage node includes a capacitor.

10. The active matrix device of claim 1 , wherein the matrix elements each include a plurality of data storage capacitances for storing a plurality of bits of data per matrix element.

11. The active matrix device of claim 10 , including a plurality of row address lines controlling a plurality of address thin film transistors connected to respective data storage capacitances to select one or more of the data storage capacitances.

12. The active matrix device of claim 11 , wherein the plurality of address thin film transistors are connected to a common drive line connected through a select transistor to the column line, wherein the select transistor is controlled by a select line.

13. The active matrix device of claim 12 , including a refresh line controlling the refresh circuit to connect the refresh circuitry to the common drive line to refresh the selected data storage capacitor.

14. The active matrix device of claim 10 , wherein:

each matrix element includes a plurality of register units connected in series,

each register unit including a data storage node, and register units connected to subsequent register units including a driver that is configured to drive the next register unit; and

at least one clock line is provided for controlling the transmission of data along the series of register units.

15. The active matrix device of claim 14 , wherein in each register unit, an output of the driver is connected back to the storage node for refreshing data stored on the storage node so that the driver constitutes the refresh circuit.

16. The active matrix device of claim 1 , wherein the refresh circuitry includes a pair of cross-coupled inverters.

17. The active matrix device of claim 1 , wherein the matrix elements are display pixels for displaying an image pixel in accordance with data stored on the data storage node.

18. The active matrix device of claim 1 , wherein the matrix elements are pixel electrodes for controlling liquid crystal.

19. A method of operating an active matrix device having matrix elements including capacitative storage nodes, comprising:

storing image data as charge on the storage nodes, and

operating the active matrix device in a refresh mode including

displaying the stored image data, and

periodically applying refresh signals to refresh circuitry within the matrix elements to cause the refresh circuitry to invert the image data corresponding to the charges stored on the storage nodes.

20. The method of claim 19 , further including operating the active matrix device in a normal mode including:

regularly addressing the matrix elements with fresh video information, and

displaying the video information.

Assignments (3)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 27, 2007
From: KONINKLIJKE PHILIPS ELECTRONICS N.V.
To: TPO HONG KONG HOLDING LIMITED
Reel/Frame 019265/0363 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 23, 2007
From: KONINKLIJKE PHILIPS ELECTRONICS N.V.
To: TPO HONG KONG HOLDING LIMITED
Reel/Frame 019193/0404 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jul 9, 2002
From: EDWARDS, MARTIN J.; AYRES, JOHN R. A.
To: KONINKLIJKE PHILIPS ELECTRONICS N.V.
Reel/Frame 013103/0358 →