Display device with sensing units and driving method thereof

• US 8,068,088 B2
• Filed: 01/18/2008
• Issued: 11/29/2011
• Est. Priority Date: 02/12/2007
• Status: Expired due to Fees

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Moon, Jun-Hee, Choi, Young-Jun, Rho, Soo-Guy
• Primary Examiner(s): Shankar; Vijay
• Application Number:
  US12/016,809
• Publication Number:
  US 20080192001A1
• Time in Patent Office: 1,411 Days
• Field of Search: 345 87-104, 345204-215
• US Class Current: 345/104
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence

Abstract

A display device includes a display panel having a first panel and a second panel that face each other with a liquid crystal layer therebetween, a plurality of first sense data lines extending in a row direction on the second panel, a plurality of second sense data lines extending in a column direction on the second substrate, and a sense signal processor. A plurality of sensing units are positioned at regions defined by the first and second sense data lines. A first sense data lines is connected to a second sense data line by a contact to output a first sense data signal through the first sense data line and a second sense data signal through the second sense data line. The sense signal processor reads and processes the first and second sense data signals.

Claims

1. A display device comprising:

a display panel having a first panel and a second panel that face each other with a liquid crystal layer disposed between the first panel and the second panel;

a plurality of first sense data lines extending in a row direction on the second panel;

a plurality of second sense data lines extending in a column direction on the second panel;

a plurality of sensing units positioned in regions defined by the first and second sense data lines, wherein a first sense data line is connected to a second sense data line by a contact to output a first sense data signal through the first sense data line and a second sense data signal through the second sense data line; and

a sense signal processor reading and processing the first and second sense data signals,

wherein at least one of the sensing units comprises;

a first transistor having a control terminal, a first non-control terminal connected to each of the first sense data lines, and a second non-control terminal connected to each of the second sense data lines; and

a second transistor having a control terminal receiving an initializing signal to turn off the first transistor, a first non-control terminal connected to each of the first sense data lines, and a second non-control terminal connected to the control terminal of the first transistor, and

wherein the contact is application of physical pressure to the corresponding sensing unit.

2. The display device of claim 1, wherein the display panel further comprises a common electrode supplied with a common voltage and formed on the first panel.

3. The display device of claim 2, wherein the display panel further comprises a protrusion facing the control terminal of the first transistor, wherein the protrusion is disposed between the first panel and the common electrode.

4. The display device of claim 3, wherein the sense signal processor comprises:

a plurality of first processing circuits connected to the first sense data lines, wherein the first processing circuits generate a first processed signal based on the first sense data signal;

a plurality of second processing circuits connected to the second sense data lines, wherein the second processing circuits generate a second processed signal based on the second sense data signal; and

a storing unit storing the first and second processed signals.

5. The display device of claim 4, wherein each of the first processing circuits comprises:

a first resistor connected between a first voltage and the first sense data line;

a first switching element connected between a second voltage and the first sense data line;

a first comparator comparing the first sense data signal from the first sense data line and a reference voltage to generate the first processed signal;

a first flip-flop storing the first processed signal; and

a second switching element connected between the first comparator and the first flip-flop, and

wherein each of the second processing circuits comprises;

a second resistor connected between the first voltage and the second sense data line;

a third switching element connected between the second voltage and the second sense data line;

a second comparator comparing the second sense data signal from the second sense data line and the reference voltage to generate the second processed signal;

a second flip-flop storing the second processed signal; and

a fourth switching element connected between the second comparator and the second flip-flop.

6. The display device of claim 5, wherein the first and fourth switching elements are simultaneously turned on, and the second and third switching elements are simultaneously turned on.

7. The display device of claim 5, wherein the first flip-flop is in synchronization with a first clock signal and simultaneously outputs the first processed signal to the storing unit, and the second flip-flop is in synchronization with a second clock signal and simultaneously outputs the second processed signal to the storing unit.

8. The display device of claim 4, wherein the sense signal processor further comprises a controller that outputs a control signal to control the first and second processing circuits and the initializing signal.

9. The display device of claim 4, further comprising a contact determiner that receives the first and second processed signals and determines a contact position.

10. The display device of claim 9, wherein the contact determiner comprises:

a first determiner that receives the first processed signal to determine an X-axis coordinate of a contact;

a second determiner that receives the second processed signal to determine a Y-axis coordinate of the contact; and

a register that stores the X-axis and Y-axis coordinate of the contact in a flag.

11. The display device of claim 10, wherein the contact determiner further comprises an interface that outputs values stored in the flag.

12. A method of driving a display device having a plurality of first sense data lines extending in a row direction, a plurality of second sense data lines extending in a column direction, a plurality of sensing units connected to the first and second sense data lines and sensing a contact, the method comprising:

connecting at least one of the first sense data lines and at least one of the second sense data lines through at least one of the sensing units when a contact occurs;

applying a first voltage to the second sense data lines;

reading voltage variations of the first sense data lines as first sense data signals and generating first processed signals based on the first sense data lines;

applying the first voltage to the first sense data lines;

reading voltage variations of the second sense data lines as second sense data signals and generating second processed signals based on the second sense data lines; and

determining contact information based on the first and second processed signals.

13. The method of claim 12, wherein the generation of the first and second processed signals comprises comparing voltages of the first and second sense data lines and a reference voltage to generate the first and second processed signals.

14. The method of claim 13, further comprising:

substantially simultaneously writing the first processed signals in a register after generating the first processed signals; and

substantially simultaneously writing the second processed signals in the register after generating the second processed signals.

15. The method of claim 14, wherein the determination of the contact information comprises:

outputting the first and second processed signals written in the register;

determining an X-axis coordinate of the contact based on the first processed signals;

determining a Y-axis coordinate of the contact based on the second processed signals; and

storing an indication that the contact has occurred and the X-axis and Y-axis coordinates of the contact.

16. The driving method of claim 15, wherein each of the sensing units comprises a transistor having a control terminal, a first terminal connected to each of the first sense data lines, and a second terminal connected to each of the second sense data lines, and the control terminal is connected to a common electrode by a contact.

17. The driving method of claim 16, wherein the display device comprises a liquid crystal layer, a lower substrate having the sensing units, and an upper substrate having the common electrode.

18. The driving method of claim 17, wherein the upper substrate comprises a protrusion facing the control terminal of the transistor, wherein the protrusion is formed under the common electrode.

19. The driving method of claim 18, further comprising turning off the transistor before applying the first voltage to the second sense data lines.

20. A display device comprising:

a display panel having a first substrate and a second substrate that face each other with a liquid crystal layer disposed between the first substrate and the second substrate;

a plurality of first sense data lines extending in a row direction on the second substrate;

a plurality of second sense data lines extending in a column direction on the second substrate;

a plurality of sensing units positioned in regions defined by the first and second sense data lines, wherein a first sense data line is connected to a second sense data lines by a contact to output a first sense data signal through the first sense data line and a second sense data signal through the second sense data line; and

a sense signal processor reading and processing the first and second sense data signals,

wherein a common electrode receiving a common voltage is located on top of the first substrate and has a protrusion,

wherein at least one of the sensing units comprises a transistor,

wherein the transistor has a control terminal, a first non-control terminal connected to each of the first sense data lines, a second non-control terminal connected to each of the second sense data lines, and

wherein the control terminal is located on top of the second substrate, a contact member is located on top of the control terminal, a part of the contact member overlaps with the protrusion, and the part of the contact member contacts the protrusion when a physical touch applied to the first substrate over the protrusion applies sufficient pressure to bring the contact member into contact with the protrusion.

21. The display device of claim 20, wherein the corresponding sensing unit comprises a switching element connected between the first non-control terminal and the control terminal of the transistor, wherein the switching element turns off the transistor based on an initializing signal.