Electronic pen for detecting touch location and method and apparatus for detecting touch location

• US 8,334,855 B2
• Filed: 12/23/2009
• Issued: 12/18/2012
• Est. Priority Date: 06/15/2009
• Status: Expired due to Fees

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Choi, Im-Su, Do, Hyun-Chul
• Primary Examiner(s): Sniezek, Andrew L
• Application Number:
  US12/646,955
• Publication Number:
  US 20100315357A1
• Time in Patent Office: 1,091 Days
• Field of Search: None
• US Class Current: 345/179
• CPC Class Codes: G06F 3/037 using the raster scan of a cathode-ray tube [CRT] for detecting the position of the member, e.g. light pens cooperating with CRT monitors

Abstract

An electronic pen for detecting a touch location on a display panel by detecting infrared rays generated by the display panel, the electronic pen including an infrared sensor that detects the infrared rays and generates a detection signal; an amplifying unit that amplifies the detection signal; a low pass filter that filters high-frequency elements from the amplified detection signal; and a location detecting unit that detects the location on the display panel touched by the electronic pen based on the filtered detection signal.

Claims

1. An electronic pen for detecting a touch location on a display panel by detecting infrared rays generated by the display panel, the electronic pen comprising:

an infrared sensor configured to detect the infrared rays and to generate a detection signal;

an amplifying unit configured to amplify the detection signal;

a low pass filter configured to filter high-frequency elements from the amplified detection signal; and

a location detecting unit configured to detect a detected touch location on the display panel touched by the electronic pen based on the filtered detection signal.

2. The electronic pen of claim 1, wherein the location detecting unit further comprises a comparing unit configured to compare the filtered detection signal to a reference value, and

wherein the location detecting unit configured to determine that the electronic pen touches the display panel only when a value of the filtered detection signal is greater than the reference value.

3. The electronic pen of claim 2, wherein the location detecting unit further comprises:

a time measuring unit configured to measure a time difference between a scanning starting time point at which scanning in the display panel started and a time point at which the infrared rays are detected; and

a location calculating unit configured to calculate the detected touch location touched by the electronic pen based on the time difference measured by the time measuring unit.

4. The electronic pen of claim 3, wherein the time point at which the infrared rays are detected is a time point at which the filtered detection signal has a peak value.

5. The electronic pen of claim 1, further comprising a communication unit configured to transmit information regarding the detected touch location to the display panel.

6. The electronic pen of claim 1, wherein the display panel is a plasma display panel.

7. A method of detecting a location on a display panel touched by an electronic pen by detecting infrared rays generated by the display panel, the method comprising:

detecting the infrared rays and generating a detection signal;

amplifying the detection signal;

filtering high-frequency elements from the amplified detection signal; and

detecting a detected touch location touched by the electronic pen based on the filtered detection signal.

8. The method of claim 7, wherein the detecting of the location comprises comparing the filtered detection signal to a reference value, and

determining that the display panel is touched by the electronic pen only when a value of the filtered detection signal is greater than the reference signal.

9. The method of claim 8, wherein the detecting of the location comprises:

measuring a time difference between a scanning starting time point at which scanning in the display panel started and a time point at which the infrared rays are detected; and

calculating the detected touch location touched by the electronic pen based on the measured time difference.

10. The method of claim 9, wherein the time point at which the infrared rays are detected is a time point at which the filtered detection signal has a peak value.

11. The method of claim 7, further comprising transmitting information regarding the detected touch location to the display panel.

12. The method of claim 7, wherein the display panel is a plasma display panel.

13. An apparatus for detecting a touch location, the apparatus comprising:

a plasma display panel including;

scan electrodes and sustain electrodes extending parallel with each other along a first direction; and

address electrodes extending along a second direction substantially perpendicular to the first direction of the scan electrodes and the sustain electrodes;

an electronic pen configured to detect a location touched by the electronic pen by detecting infrared rays generated by the plasma display panel,

wherein the electronic pen comprises;

an infrared sensor configured to detect the infrared rays and to generate a detection signal;

an amplifying unit configured to amplify the detection signal;

a low pass filter configured to filter high-frequency elements from the amplified detection signal; and

a location detecting unit configured to detect a detected touch location on the plasma display panel touched by the electronic pen based on the filtered detection signal.

14. The apparatus of claim 13, wherein a unit frame of the plasma display panel is divided into a plurality of sub-fields to display gradation and to provide a location detection scanning period.

15. The apparatus of claim 14, wherein the location detection scanning period comprises an X coordinate scanning period and a Y coordinate scanning period,

wherein location scanning signals are sequentially applied to the scan electrodes during the X coordinate scanning period, and

wherein location scanning signals are sequentially applied to the address electrodes during the Y coordinate scanning period.

16. The apparatus of claim 15, wherein the infrared sensor detects the infrared rays generated by the plasma display panel due to the application of the location scanning signals.

17. The apparatus of claim 16, wherein the location detecting unit further comprises a comparing unit configured to compare the filtered detection signal to a reference value, and

wherein the location detecting unit configured to determine that the electronic pen touches the plasma display panel only when a value of the filtered detection signal is greater than the reference value.

18. The apparatus of claim 17, wherein the location detecting unit further comprises:

a time measuring unit configured to measure a time difference between a scanning starting time point at which scanning in the plasma display panel started and a time point at which the infrared rays are detected; and

a location calculating unit configured to calculate the location touched by the electronic pen based on a time difference measured by the time measuring unit.

19. The apparatus of claim 18, wherein the time point at which the infrared rays are detected is a time point at which the filtered detection signal has a peak value, and

the scanning starting time point is a time point at which scanning starts for either the X coordinate scanning period or the Y coordinate scanning period.

20. The apparatus of claim 13, further comprising a communication unit configured to transmit information regarding the detected touch location to the plasma display panel.