Touch position detecting device, method of detecting touch position and touch screen display device having the same

• US 7,952,563 B2
• Filed: 12/30/2005
• Issued: 05/31/2011
• Est. Priority Date: 12/31/2004
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Cho, Man-Seung, Lee, Joo-Hyung, Park, Jong-Woung, Uh, Kee-Han, Kim, Hyung-Guel, Cha, Young-Ok
• Primary Examiner(s): Nguyen; Kevin M
• Assistant Examiner(s): Lee, Jr.; Kenneth B
• Application Number:
  US11/322,933
• Publication Number:
  US 20060146038A1
• Time in Patent Office: 1,978 Days
• Field of Search: 345173-179, 178 1801- 1811, 178 1901- 1907
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/1362 Active matrix addressed cells G02F1/134336, G02F1/134363 take precedence
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/042 by opto-electronic means
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336

Abstract

A touch position detecting method, a device using the method, and a touch screen display device having the device are disclosed. A touch sensing unit senses a touch event and outputs a sensing data. A reference update unit updates a reference data with an n-th frame sensing data provided from the touch sensing unit, based on a predetermined update signal. A position detecting unit detects the touch position by using the reference data and an (n+i)-th frame sensing data from the touch sensing unit. Therefore, the touch position is easily detected by determining a difference between the reference data and the sensing data at a certain time.

Claims

1. A touch position detecting device comprising:

a touch sensing unit which senses a touch event and outputs a sensing data;

a sensor control unit which receives n-th frame sensing data from the touch sensing unit;

a sensing signal adjusting unit which receives the n-th frame sensing data and adjusts a level of the n-th frame sensing data to be at a constant level by determining a difference between an external light sensing data and an internal light sensing data;

a touch position detecting unit which receives the n-th frame sensing data, stores the n-th frame sensing data in a first memory, updates a reference data stored in a second memory with the n-th frame sensing data provided from the touch sensing unit based on an update signal, and detects a touch position by determining a difference between the reference data and an (n+i)-th frame sensing data provided from the touch sensing unit, wherein

‘

n’ and

‘

i’

are natural numbers,

the reference data corresponds to the n-th frame sensing data, and

the n-th frame sensing data is previous to the (n+i)-th frame sensing data.

2. The touch position detecting device of claim 1, wherein the update signal corresponds to a turn-on signal which turns on the touch position detecting device.

3. The touch position detecting device of claim 1, wherein the update signal comprises a wake-up signal which wakes up the touch position detecting device.

4. The touch position detecting device of claim 1, wherein the update signal comprises at least one of a turn-on signal which turns on the touch position detecting device, a wake-up signal which wakes up the touch position detecting device, a post-event sensing signal, and an update control signal from a sensing signal adjusting unit.

5. The touch position detecting device of claim 1, further comprising a post-event sensing unit which senses whether a physical object is detached from the touch sensing unit, and outputs a post-event sensing signal, wherein the touch position detecting unit updates the reference data with the n-th frame sensing data provided from the touch sensing unit, when the post-event sensing signal is applied to the reference update unit.

6. The touch position detecting device of claim 5, wherein the sensing data comprises a background sensing data corresponding to a sensing data with no touch event occurring, and the touch position detecting unit further comprises a calculation unit which decides whether to update the reference data with the n-th frame sensing data, when a level of an object sensing data corresponding to a sensing data of touch event is lower than a level of the background sensing data.

7. The touch position detecting device of claim 6, wherein the calculation unit decides whether to update the reference data, based on a difference of levels between object sensing data of a previous sensing data and object sensing data of a current sensing data.

8. The touch position detecting device of claim 7, wherein the calculation unit decides to update the reference data, when the difference of levels between the object sensing data of a previous sensing data and the object sensing data of a current sensing data is larger than a predetermined critical value.

9. The touch position detecting device of claim 7, wherein the calculation unit updates the reference data with the n-th frame sensing data when the difference of levels between the object sensing data of a previous sensing data and the object sensing data of a current sensing data stops increasing and then begins decreasing.

10. The touch position detecting device of claim 7, wherein the calculation unit updates the reference data with the n-th frame sensing data before the difference of levels between the object sensing data of a previous sensing data and the object sensing data of a current sensing data begins to decrease, when the difference of levels stops increasing and then begins decreasing.

11. The touch position detecting device of claim 1, wherein the sensing signal adjusting unit provides the update signal to the reference update unit when the sensing data is maintained at a constant level.

12. The touch position detecting device of claim 11, wherein, if the sensing data is not within a predetermined range, one of a gate voltage adjusting operation, an amplification gain adjusting operation, and a backlight adjusting operation is performed until the sensing data is within the predetermined range.

13. The touch position detecting device of claim 11, wherein the sensing signal adjusting unit further comprises at least one of a gate voltage adjusting unit, an amplification gain adjusting unit, and a backlight adjusting unit for adjusting the sensing data to fall within a predetermined range.

14. The touch position detecting device of claim 1, further comprising a filter which eliminated a noise element by comparing a previously detected touch position with a currently detected touch position.

29. The touch position detecting device of claim 1, wherein the touch sensing unit further comprises an external light sensing unit which generates an external light sensing signal and an internal light sensing unit which generates an internal light sensing signal, and the sensing signal adjusting unit compares an external light sensing data processed from the external light sensing signal with an internal light sensing data processed from the internal light sensing signal.

15. A method of detecting touch position, comprising:

receiving an n-th frame sensing data and adjusting a level of the n-th frame sensing data to be at a constant level by determining a difference between an external light sensing data and an internal light sensing data;

updating a reference data with the n-th frame sensing data indicating that a touch event occurs, according to an update control signal externally provided; and

detecting a touch position data corresponding to a position at which the touch event occurs, by determining a difference between the reference data and a (n+i)-th frame sensing data, wherein

‘

n’ and

‘

i’

are natural numbers,

the reference data corresponds to the n-th frame sensing data, and

the n-th frame sensing data is previous to the (n+i)-th frame sensing data.

16. The method of claim 15, wherein touch position is detected on a touch screen liquid crystal display device.

17. The method of claim 15, further comprising:

generating a post-event sensing signal indicating that the touch event is over;

examining whether the method is performed under a shadow mode indicating that sensing data of external surroundings has higher level than sensing data of a touched object or a backlight mode, according to the post-event sensing signal; and

updating the reference data with the n-th frame sensing data, when the method is determined to be performed under the backlight mode indicating that the sensing data of the external surroundings has a lower level than the sensing data of the touched object.

18. The method of claim 17, further comprising deciding whether to update the reference data with the n-th frame sensing data, when the method is determined to be performed under the shadow mode.

19. A touch screen display device comprising:

a display panel which displays images by frame;

a sensing unit which senses a touch event by the frame to output a sensing data by the frame;

a sensing signal adjusting unit which receives an n-th frame sensing data from the sensing unit and adjusts a level of the n-th frame sensing data to be at a constant level by determining a difference between an external light sensing data and an internal light sensing data; and

a touch position detecting unit which updates a reference data with an n-th frame sensing data provided from the sensing unit, based on an update control signal, and which detects a touch position data corresponding to the touch event using the reference data and an (n+i)-th frame sensing data provided from the sensing unit, wherein

‘

n’ and

‘

i’

are natural numbers,

the reference data corresponds to the n-th frame sensing data, and

the n-th frame sensing data is previous to the (n+i)-th frame sensing data.

20. The device of claim 19, wherein the sensing unit is integrated on the display panel.

21. The device of claim 20, wherein the display panel includes an array substrate, a color filter substrate, and a liquid crystal layer interposed between the array substrate and the color filter substrate, the sensing unit integrated into the array substrate.

22. The device of claim 19, wherein the touch position detecting unit comprises:

a controller which updates the reference data with the n-th frame sensing data, based on the update control signal;

a memory which stores the reference data; and

a position detecting unit which detects the touch position data by determining a difference between the reference data and the (n+i)-th frame sensing data.

23. The device of claim 22, wherein the sensing unit further comprises a first sensor which recognizes when an object is detached from the display panel, and outputs a post-event sensing signal indicating when the object is detached from the display panel, to the controller.

24. The device of claim 23, wherein the controller decides whether an operation mode is a shadow mode indicating that sensing data of external surroundings has a higher level than sensing data of a touched object, or whether an operation mode is a backlight mode indicating that the sensing data of the external surroundings has a lower level than the sensing data of the touched object, and the reference updating unit updates the reference data with the sensing data provided from the sensing unit, according to the operation mode, when the post-event sensing signal is received.

25. The device of claim 24, wherein the controller updates the reference data with the n-th frame sensing data, when the operation mode is determined to be the backlight mode.

26. The device of claim 24, wherein the device further comprises a calculation unit which decides whether to update the reference data with the n-th frame sensing data, when the operation mode is determined to be the shadow mode.

27. The device of claim 19, wherein the sensing data comprises an object sensing data corresponding to sensing data of a touch event and a background sensing data corresponding to sensing data without a touch event occurring, and further comprises a sensing signal adjusting unit which stabilizes a difference between the object sensing data and the background sensing data.

28. The device of claim 27, wherein the sensing signal adjusting unit provides the touch position detecting unit with an update signal, when the difference between the object sensing data and the background sensing data is stabilized.