Apparatus and method for preventing noise of touch screen

• US 20040100450A1
• Filed: 02/19/2003
• Published: 05/27/2004
• Est. Priority Date: 11/21/2002
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Choi, Hyun-Seok
• Granted Patent: US 6,961,050 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally

Abstract

An apparatus and method for preventing noise in a touch screen using a predetermined number of gates that substantially eliminates noise in advance and reduces cost includes an analog-to-digital converter (ADC) which converts received analog source data into digital source data, and sends the converted data. An input detection signal generator generates and sends an input detection signal containing information on a period from when the ADC receives analog source data to when the ADC finishes the conversion. A noise-preventing clock generator receives the input detection signal, generates a predetermined clock signal, and by referring to the information on the period contained in the received input detection signal, during the period from when analog source data is received to when the conversion is finished, disabling the generated clock signal and sending the clock signal. During the remaining period, the disabling is released and the clock signal is sent.

Claims

1. A noise-preventing apparatus comprising:

an analog-to-digital converting unit converts received analog source data into digital source data, and outputs the converted data;

an input detection signal generation unit which generates an input detection signal containing information on a period from when the analog-to-digital converting unit receives analog source data to when the analog-to-digital converting unit finishes conversion of the received analog source data into digital source data, and transmits the input detection signal; and

a noise-preventing clock generation unit which receives the transmitted input detection signal, generates a predetermined clock signal, and based on information on the period included in the received input detection signal, disables the generated clock signal and sends the clock signal during the period from when analog source data is received to when conversion of the analog source data to digital source data is finished, and releases the disabling and sends the clock signal during a remaining period.

2. The apparatus of claim 1, wherein the digital source data is obtained by sampling predetermined digital data corresponding to the analog source data.

3. The apparatus of claim 2, wherein conversion of the analog source data to digital source data is finished when the sampling is completed.

4. A touch screen noise-preventing video clock generation apparatus comprising:

an analog-to-digital converting unit which converts received analog coordinate data into digital coordinate data, and outputs the converted data;

an input detection signal generation unit which generates an input detection signal at a “

high”

logic level during a period from when the analog-to-digital converting unit receives analog coordinate data to when the analog-to-digital converting unit finishes conversion of the received analog coordinate data into digital coordinate data and is at a “

low”

logic level during a remaining period, and outputs the signal; and

a noise-preventing video clock generation unit which receives the input detection signal, generates a video pixel clock signal commanding display of video pixels in each predetermined cycle, generates a video line clock signal commanding display of a video line in each cycle that is a multiple of the predetermined cycle, using the generated video pixel clock signal, and during a period from when the received input detection signal and the generated video line clock signal are in a “

high”

logic level to when the received input detection is transited to a “

low”

logic level, holds the state of the generated video pixel clock signal in a “

low”

logic level and sends the video line clock signal that is held in a “

high”

logic level as a result of holding the video pixel clock signal in a “

low”

logic level, and during the remaining period releases the holding and sends the video line clock signal.

5. The apparatus of claim 4, wherein the digital coordinate data is obtained by sampling predetermined digital data corresponding to the analog coordinate data.

6. The apparatus of claim 5, wherein conversion of the analog coordinate data to digital coordinate data is finished when the sampling is completed.

7. The apparatus of claim 6, wherein the analog-to-digital converting unit begins conversion into digital coordinate data when the received input detection signal is in a “

high”

logic level and the generated video line clock signal is in a “

high”

logic level.

8. A touch screen noise-preventing apparatus comprising:

a touch screen input unit that generates and transmits analog coordinate data when an input to a predetermined location of a touch screen panel is received;

a touch screen input control unit which receives the analog coordinate data transmitted from the touch screen input unit, converts the received analog coordinate data into digital coordinate data and outputs the converted data, and generates and transmits an input detection signal in a “

high”

logic level during a period from when analog coordinate data is received to when conversion of the analog coordinate data to digital coordinate data is finished, and is in a “

low”

logic level during a remaining period;

a noise-preventing video clock generation unit which receives the transmitted input detection signal, generates a video pixel clock signal commanding display of video pixels in a predetermined cycle, generates a video line clock signal commanding display of a video line in each cycle that is a multiple of the predetermined cycle, by using the generated video pixel clock signal, and during a period from when the received input detection signal and the generated video line clock signal are in a “

high”

logic level to when the received input detection is transited to a “

low”

logic level, holds a state of the generated video pixel clock signal in a “

low”

logic level and sends the video line clock signal held in a “

high”

logic level as a result of holding the video pixel clock signal in a “

low”

logic level, and during a remaining period, releases the holding and sends the video line clock signal;

a central control unit which generates video data corresponding to the digital coordinate data received from the touch screen input control unit, and outputs the video data;

a video output control unit which receives and stores the video data output from the central control unit, receives the video line clock signal and video pixel clock signal from the noise-preventing video clock generation unit, sends predetermined pixel data among stored video data in each cycle of the received pixel clock signal, and sends the received video line clock signal and video pixel clock signal; and

a video output unit which receives the pixel data, video pixel clock signal, and video line clock signal sent by the video output control unit, inputs the received pixel data to a predetermined video display panel in each cycle of the received video pixel clock signal, and inputs a predetermined driving voltage to the video display panel in each cycle of the received video line clock signal so that a video is output.

9. The apparatus of claim 8, wherein the digital coordinate data is obtained by sampling predetermined digital data corresponding to the analog coordinate data.

10. The apparatus of claim 9, wherein the analog coordinate data is converted into digital coordinate data when the sampling is finished.

11. The apparatus of claim 10, wherein the touch screen input control unit begins conversion into the digital coordinate data when the received input detection signal is in a “

high”

logic level and the generated video line clock signal is in a “

high”

logic level.

12. The apparatus of claim 8, wherein the video display panel is a thin film transistor (TFT) LCD panel.

13. The apparatus of claim 12, wherein the video pixel clock signal is a pulse that provides a cycle for switching a TFT of said TFT LCD panel.

14. The apparatus of claim 13, wherein the video output unit inputs the received pixel data in each cycle of the received video pixel clock signal cycle, to a source terminal of the TFT of a liquid crystal device of the TFT LCD panel on which the pixel data is to be displayed, and inputs a predetermined driving voltage in each cycle of the received video line clock signal to a gate terminal of the TFT.

15. A noise-preventing clock generation method comprising:

(a) converting received analog source data into digital source data, and outputting the converted, received digital source data;

(b) generating an input detection signal containing information on the period from when analog source data is received to when conversion of the analog source data to digital source data is finished, and sending the input detection signal; and

(c) receiving the sent input detection signal, generating a predetermined clock, and based on information contained in the received input detection signal, during the period from when analog source data is received to when conversion of the analog source data to digital source data is finished, disabling and sending the generated predetermined clock signal, and during a remaining period, releasing the disabling and sending the predetermined clock signal.

16. The method of claim 15, wherein the digital source data is obtained by sampling predetermined digital data corresponding to the received analog source data.

17. The method of claim 16, wherein conversion of the analog source data to digital source data is finished when the sampling is completed.

18. A touch screen noise-preventing video clock generation method comprising:

(a) converting analog coordinate data received from a touch screen panel into digital coordinate data, and sending the converted, received digital coordinate data;

(b) generating and sending an input detection signal which is in a “

high”

logic level during a period from when analog coordinate data is received to when conversion of the analog coordinate data to digital coordinate data is finished and in a “

low”

logic level during a remaining period; and

(c) receiving the sent input detection signal, generating a video pixel clock signal commanding display of video pixels in each predetermined cycle and a video line clock signal commanding display of a video line in each cycle that is a multiple of the predetermined cycle by using the generated video pixel clock signal, and during a period from when the received input detection signal and the generated video line clock signal are in a “

high”

logic level to when the received input detection is transited to a “

low”

logic level, holding the state of the generated video pixel clock signal in a “

low”

logic level and sending the video line clock signal that is held in a “

high”

logic level as a result of holding the video pixel clock signal in a “

low”

logic level, and during a remaining period, releasing the holding and sending the video line clock signal.

19. The method of claim 18, wherein the digital coordinate data is obtained by sampling predetermined digital data corresponding to the received analog coordinate data.

20. The method of claim 19, wherein the analog coordinate data is converted into digital coordinate data when the sampling is finished.

21. The method of claim 20, wherein in step (a) the converting begins when the received input detection signal is in a “

high”

logic level and the generated video line clock signal is in a “

high”

logic level.

22. A touch screen noise-preventing method comprising:

(a) if a touch input is received on a touch screen panel, generating analog coordinate data indicating the coordinates of a location of said touch input and sending the data;

(b) receiving the sent analog coordinate data, converting the received analog coordinate data into digital coordinate data, outputting the converted data, generating and transmitting an input detection signal at a “

high”

logic level during a period from when analog coordinate data is received to when conversion of the analog coordinate data to digital coordinate data is finished and is in a “

low”

logic level during a remaining period;

(c) receiving the transmitted input detection signal, generating a video pixel clock signal commanding display of video pixels in each predetermined cycle and a video line clock signal commanding to display a video line in each cycle that is a multiple of the predetermined cycle, by using the generated video pixel clock signal, and during a period from when the received input detection signal and the generated video line clock signal are in a “

high”

logic level to when the received input detection is transited to a “

low”

logic level, holding a state of the generated video pixel clock signal in a “

low”

logic level and sending the video line clock signal that is held in a “

high”

logic level as a result of holding the video pixel clock signal in a “

low”

logic level, and during the remaining period, releasing the holding and sending the video line clock signal;

(d) receiving the sent digital coordinate data, generating video data corresponding to the received digital coordinate data, and sending the video data;

(e) receiving and storing the sent video data, receiving the sent video line clock signal and video pixel clock signal, sending predetermined pixel data among the stored video data in each cycle of the received video pixel, and sending the received video line clock signal and video pixel clock signal; and

(f) receiving the sent pixel data, video pixel clock signal, and video line clock signal, inputting the received pixel data to a predetermined video display panel in each cycle of the received video pixel clock signal, and inputting a predetermined driving voltage to the video display panel in each cycle of the received video line clock signal so that a video is output.

23. The method of claim 22, wherein the digital coordinate data is obtained by sampling predetermined digital data corresponding to the analog coordinate data.

24. The method of claim 23, wherein the analog coordinate data is converted into digital coordinate data when the sampling is finished.

25. The method of claim 24, wherein in step (b) converting into digital coordinate data begins when the received input detection signal is in a “

high”

logic level and the generated video line clock signal is in a “

high”

logic level.

26. The method of claim 22, wherein the video display panel is a thin film transistor (TFT) liquid crystal display (LCD) panel.

27. The method of claim 26, wherein the video pixel clock signal is a pulse that provides a cycle for switching a TFT of the TFT LCD panel.

28. The method of claim 27, wherein in step (f), in each cycle of the received video pixel clock signal the received pixel data is transmitted to a source terminal of the TFT of a liquid crystal device of the TFT LCD panel, the device on which the pixel data is to be displayed, and in each cycle of the received video line clock signal a predetermined driving voltage is input to a gate terminal of the TFT.

29. A computer readable medium having embodied thereon a computer program, said program performing the steps of:

(a) converting received analog source data into digital source data, and outputting the converted, received digital source data;

(b) generating an input detection signal containing information on the period from when analog source data is received to when conversion of the analog source data to digital source data is finished, and sending the input detection signal; and

(c) receiving the sent input detection signal, generating a predetermined clock, and based on information contained in the received input detection signal, during the period from when analog source data is received to when conversion of the analog source data to digital source data is finished, disabling and sending the generated predetermined clock signal, and during a remaining period, releasing the disabling and sending the predetermined clock signal.

30. The computer readable medium of claim 29, wherein the digital source data is obtained by sampling predetermined digital data corresponding to the received analog source data.

31. The computer readable medium of claim 30, wherein the conversion is finished when the sampling is completed.

32. A computer readable medium having embodied thereon a computer program, said program performing the steps of:

(a) converting analog coordinate data received from a touch screen panel into digital coordinate data, and sending the converted, received digital coordinate data;

(b) generating and sending an input detection signal which is in a “

high”

logic level during a period from when analog coordinate data is received to when conversion of the analog coordinate data to digital coordinate data is finished and in a “

low”

logic level during a remaining period; and

(c) receiving the sent input detection signal, generating a video pixel clock signal commanding display of video pixels in each predetermined cycle and a video line clock signal commanding display of a video line in each cycle that is a multiple of the predetermined cycle by using the generated video pixel clock signal, and during a period from when the received input detection signal and the generated video line clock signal are in a “

high”

logic level to when the received input detection is transited to a “

low”

logic level, holding the state of the generated video pixel clock signal in a “

low”

logic level and sending the video line clock signal that is held in a “

high”

logic level as a result of holding the video pixel clock signal in a “

low”

logic level, and during a remaining period, releasing the holding and sending the video line clock signal.

33. The computer readable medium of claim 32, wherein the digital coordinate data is obtained by sampling predetermined digital data corresponding to the received analog coordinate data.

34. The computer readable medium of claim 33, wherein the analog coordinate data is converted into digital coordinate data when the sampling is finished.

35. The computer readable medium of claim 34, wherein in step (a) the converting begins when the received input detection signal is in a “

high”

logic level and the generated video line clock signal is in a “

high”

logic level.

36. A computer readable medium having embodied thereon a computer program, said program performing the steps of:

(a) if a touch input is received on a touch screen panel, generating analog coordinate data indicating the coordinates of a location of said touch input and sending the data;

(b) receiving the sent analog coordinate data, converting the received analog coordinate data into digital coordinate data, outputting the converted data, generating and transmitting an input detection signal at a “

high”

logic level during a period from when analog coordinate data is received to when conversion of the analog coordinate data to digital coordinate data is finished and is in a “

low”

logic level during a remaining period;

(c) receiving the transmitted input detection signal, generating a video pixel clock signal commanding display of video pixels in each predetermined cycle and a video line clock signal commanding to display a video line in each cycle that is a multiple of the predetermined cycle, by using the generated video pixel clock signal, and during a period from when the received input detection signal and the generated video line clock signal are in a “

high”

logic level to when the received input detection is transited to a “

low”

logic level, holding a state of the generated video pixel clock signal in a “

low”

logic level and sending the video line clock signal that is held in a “

high”

logic level as a result of holding the video pixel clock signal in a “

low”

logic level, and during the remaining period, releasing the holding and sending the video line clock signal;

(d) receiving the sent digital coordinate data, generating video data corresponding to the received digital coordinate data, and sending the video data;

(e) receiving and storing the sent video data, receiving the sent video line clock signal and video pixel clock signal, sending predetermined pixel data among the stored video data in each cycle of the received video pixel, and sending the received video line clock signal and video pixel clock signal; and

(f) receiving the sent pixel data, video pixel clock signal, and video line clock signal, inputting the received pixel data to a predetermined video display panel in each cycle of the received video pixel clock signal, and inputting a predetermined driving voltage to the video display panel in each cycle of the received video line clock signal so that a video is output.

37. The computer readable medium of claim 36, wherein the digital coordinate data is obtained by sampling predetermined digital data corresponding to the analog coordinate data.

38. The computer readable medium of claim 37, wherein the analog coordinate data is converted into digital coordinate data when the sampling is finished.

39. The computer readable medium of claim 38, wherein in step (b) converting into digital coordinate data begins when the received input detection signal is in a “

high”

logic level and the generated video line clock signal is in a “

high”

logic level.

40. The computer readable medium of claim 36, wherein the video display panel is a thin film transistor (TFT) liquid crystal display (LCD) panel.

41. The computer readable medium of claim 40, wherein the video pixel clock signal is a pulse that provides a cycle for switching a TFT of the TFT LCD panel.

42. The method of claim 41, wherein in step (f), in each cycle of the received video pixel clock signal the received pixel data is transmitted to a source terminal of the TFT of a liquid crystal device of the TFT LCD panel, the device on which the pixel data is to be displayed, and in each cycle of the received video line clock signal a predetermined driving voltage is input to a gate terminal of the TFT.