Display-integrated coordinate input device

• US 5,940,064 A
• Filed: 07/03/1997
• Issued: 08/17/1999
• Est. Priority Date: 02/21/1994
• Status: Expired due to Fees

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Okuno, Takeshi, Kai, Tsutomu, Tomitani, Hisashi, Koseki, Hideo, Fujiwara, Shouzou, Yamamoto, Masahiro, Ito, Naoyuki, Matsunami, Masahito
• Primary Examiner(s): Zimmerman, Mark K.
• Assistant Examiner(s): Laneau, Ronald
• Application Number:
  US08/888,084
• Time in Patent Office: 775 Days
• Field of Search: 345/173, 345/174, 345/87
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0441 using active external devices, e.g. active pens, for receiving changes in electrical potential transmitted by the digitiser, e.g. tablet driving signals
• 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 3/3611 Control of matrices with row and column drivers

Abstract

A liquid crystal module comprises a liquid crystal panel including mutually orthogonal row electrodes and column electrodes and a liquid crystal layer sealed between the electrodes as a display element, a row electrode driving circuit driving the row electrodes of the liquid crystal panel, and a column electrode driving circuit driving the column electrodes. A detecting electrode detects scanning signals applied to the row and column electrodes of the liquid crystal panel by electrically coupling to the electrodes with electrostatic coupling capacity. A coordinate detecting circuit converts the signals obtained from the detecting electrode into row and column coordinates. A correction arithmetic circuit corrects positional differences by using correction parameters of the device which have been obtained from output values of the coordinate detecting circuit beforehand. The display-integrated coordinate input device improves detection precision at the edges of a matrix panel.

Claims

1. A display-integrated coordinate input device comprising:

a matrix panel having more than one row electrode (y direction), more than one column electrode (x direction) and a display element sealed between said row electrodes and said column electrodes;

a row electrode device circuit for driving said row electrodes;

a column electro de d rive circuit for driving said column electrodes;

a detection electrode for detecting scanning signals applied to said row electrodes and said column electrodes by electrically coupling said row electrodes and said column electrodes with electrostatic coupling capacity;

a coordinate detection circuit for obtaining positional information from output signal s of said detection electrode;

a correction circuit for correcting coordinates output from said coordinate detection circuit;

a multiplication circuit for multiplying the corrected coordinates output from said correction circuit and for outputting detection coordinates for each x, y position of the matrix panel; and

a control circuit for controlling said matrix panel, said row electrode drive circuit, said column electrode drive circuit, said detection electrode, said coordinate detection circuit and said correction circuit;

wherein said row electrodes are disposed at right angles to said column electrodes; and

wherein the coordinate detection circuit comprises a first coordinate detection circuit and a second coordinate detection circuit;

wherein said first coordinate detection circuit is a magnitude comparator which changes its output as soon as a signal detected by the detection electrode exceeds a predetermined relative potential;

wherein said second coordinate detection circuit is a magnitude comparator which changes its output as soon as a signal detected by said detection electrode falls below the predetermined relative potential; and

wherein the correction circuit comprises an arithmetic circuit for operating the positions of the detection electrode from two coordinate values transmitted from said coordinate detection circuit.

2. The display-integrated coordinate input device as in claim 1, further comprising a means of switching a relative potential of the magnitude comparator in a row coordinate detection period and a column coordinate detection period.

3. The display-integrated coordinate input device as in claim 1, further comprising a means of switching relative potential of the magnitude comparator by detecting a driving voltage of a matrix panel.

4. The display-integrated coordinate input device as in claim 1, further comprising a means of switching a relative potential of the magnitude comparator in response to a signal intensity generated in the detection electrode.

5. The display-integrated coordinate input device as in claim 1, wherein the correction circuit further comprises an average value circuit which outputs average values of the first coordinate detection circuit and the second coordinate detection circuit;

and wherein the arithmetic circuit comprises a selector which selects the output of the second coordinate detection circuit when a coordinate is below a second predetermined value, selects the output of the first coordinate detection circuit when a coordinate is above a first predetermined value, and selects the output of said average value circuit when a coordinate falls between the first predetermined level and the second predetermined level.

6. The display-integrated coordinate input device as in claim 1, wherein the matrix panel comprises column electrodes arranged in a first predetermined direction on a first glass substrate at a first predetermined pitch, and row electrodes arranged in a second predetermined direction, which is at a right angle to said first predetermined direction, on a second glass substrate at a second predetermined pitch:

wherein said second glass substrate is disposed so as to face said first glass substrate through the display element, formed as a layer of a display material;

wherein said column electrodes and said row electrodes are led to a sealing section in a non-display area with no bending points, while maintaining said first predetermined pitch and said second predetermined pitch respectively; and

wherein said non-display area is an area other than a display area where at least said column electrodes and said row electrodes are laminated to each other.

7. The display-integrated coordinate input device as in claim 1, wherein the matrix panel comprises column electrodes arranged in a first predetermined direction on a first glass substrate at a first predetermined pitch, row electrodes arranged in a second predetermined direction, which is at a right angle to said first predetermined direction, on a second glass substrate at a second predetermined pitch, leading electrodes disposed in a non-display area and a conductive film which is applied on said leading electrodes so as to electrically shield said leading electrodes;

wherein said second glass substrate is disposed so as to face said first glass substrate through the display element, formed as a layer of a display material; and

wherein said non-display area is an area other than a display area where at least said column electrodes and said row electrodes are laminated to each other.

8. The display-integrated coordinate input device as in claim 1, wherein the matrix panel is a liquid crystal panel.

9. A display-integrated coordinate input device comprising:

a matrix panel having more than one row electrode (y direction), more than one column electrode (x direction) and a display element sealed between said row electrodes and said column electrodes;

a row electrode device circuit for driving said row electrodes;

a column electrode drive circuit for driving said column electrodes;

a detection electrode for detecting scanning signals applied to said row electrodes and said column electrodes by electrically coupling said row electrodes and said column electrodes with electrostatic coupling capacity;

a coordinate detection circuit for obtaining positional information from output signals of said detection electrode;

a correction circuit for correcting coordinates output from said coordinate detection circuit; and

a control circuit for controlling said matrix panel, said row electrode drive circuit, said column electrode drive circuit, said detection electrode, said coordinate detection circuit and said correction circuit;

wherein said row electrodes are disposed at right angles to said column electrodes; and

wherein the coordinate detection circuit comprises a first coordinate detection circuit, a second coordinate detection circuit and a third coordinate detection circuit;

wherein said first coordinate detection circuit is a magnitude comparator which changes its output as soon as a signal detected by the detection electrode exceeds a predetermined relative potential;

wherein said second coordinate detection circuit is a magnitude comparator which changes its output as soon as a signal detected by said detection electrode falls below the predetermined relative potential;

wherein said third coordinate detection circuit is a magnitude comparator which changes its output as soon as a signal detected by the detection electrode reaches a maximum value; and

wherein the correction circuit comprises an arithmetic circuit which calculates the position of the detection electrode from three coordinate values transmitted from said first coordinate detection circuit, said second coordinate detection circuit and said third coordinate detection circuit.

10. The display-integrated coordinate input device as in claim 9, further comprising a means of switching a relative potential of the magnitude comparator in a row coordinate detection period and a column coordinate detection period.

11. The display-integrated coordinate input device as in claim 9, further comprising a means of switching a relative potential of the magnitude comparator by detecting driving voltage of a matrix panel.

12. The display-integrated coordinate input device as in claim 9, further comprising a means of switching a relative potential of the magnitude comparator in response to the signal strength generated at the detection electrode.

13. The display-integrated coordinate input device as in claim 9, wherein the arithmetic circuit comprises a selector for selecting the output of the second coordinate detection circuit when a coordinate is below a second predetermined value, for selecting the output of the first coordinate detection circuit when the coordinate is above a first predetermined value, and for selecting the output of the third coordinate detection circuit when the coordinate is between the first predetermined value and the second predetermined value.

14. The display-integrated coordinate input device as in claim 9, further comprising a means for utilizing the output of the second coordinate detection circuit when a coordinate is below a second predetermined value, the output of the first coordinate detection circuit when the coordinate is above a first predetermined value and the output of the third coordinate detection ciruit when a coordinate falls between the first predetermined value and the second predetermined value;

and wherein said means gradually changes mixing ratios of outputs in response to the distance from a switching point.

15. A display-integrated coordinate input device comprising:

a matrix panel having more than one row electrode (y direction), more than one column electrode (x direction), dummy electrodes which are electrically insulated from said column electrodes and said row electrodes and are formed between tabs at a leading section of said matrix panel, and a display element sealed between said row electrodes and said column electrodes;

a row electrode drive circuit for driving said row electrodes;

a column electrode drive circuit for driving said column electrodes;

a dummy electrode drive circuit connected to said dummy electrodes which outputs a fixed voltage in a coordinate detection period;

a detection electrode for detecting scanning signals applied to said row electrodes and said column electrodes by electrically coupling said row electrodes and said column electrodes with electrostatic coupling capacity;

a coordinate detection circuit for obtaining positional information from output signals of said detection electrode; and

a control circuit for controlling said matrix panel, said row electrode drive circuit, said column electrode drive circuit, said dummy electrode drive circuit, said detection electrode, and said coordinate detection circuit;

wherein said row electrodes are disposed at right angles to said column electrodes.

16. The display-integrated coordinate input device as in claim 15, wherein the dummy electrodes on the matrix panel are provided with voltage at a level so that the display element does not respond.

17. The display-integrated coordinate input device as in claim 15, wherein the dummy electrodes are provided with signals for alternating current as applied voltage which are used in a display mode period of the matrix panel.

18. The display-integrated coordinate input device as in claim 15, wherein the matrix panel comprises column electrodes arranged in a first predetermined direction on a first glass substrate at a first predetermined pitch, and row electrodes arranged in a second predetermined direction, which is at right angle to said first predetermined direction, on a second glass substrate at a second predetermined pitch;

wherein said second glass substrate is disposed so as to face said first glass substrate through the display element, formed as a layer of a display material;

wherein said column electrodes and said row electrodes are led to a sealing section in a non-display area with no bending points, while maintaining said first predetermined pitch and said second predetermined pitch respectively; and

wherein said non-display area is an area not including a display area where at least said column electrodes and said row electrodes are laminated to each other.

19. The display-integrated coordinate input device as in claim 15, wherein the matrix panel comprises column electrodes arranged in a first predetermined direction on a first glass substrate at a first predetermined pitch, row electrodes arranged in a second predetermined direction, which is at a right angle to said first predetermined direction on a second glass substrate at a second predetermined pitch, leading electrodes disposed in a nondisplay area and a conductive film which is applied on said leading electrodes so as to electrically shield said leading electrodes;

wherein said second glass substrate is disposed so as to face said first glass substrate through the display element, formed as a layer of a display material; and

wherein said non-display area is an area not including a display area where at least said column electrodes and said row electrodes are laminated to each other.

20. The display-integrated coordinate input device as in claim 15, wherein the matrix panel is a liquid crystal panel.

21. A display-integrated coordinate input device comprising:

a matrix panel having more than one row electrode (y direction) and more than one column electrode (x direction);

a row electrode drive circuit which applies a row scanning pulse for display in response to driving conditions of said matrix panel in a display period, and supplies, by switching, a row detecting pulse for coordinate detection having a constant amplitude in a detection period, regardless of driving conditions of said display period;

a column electrode drive circuit which applies a column scanning pulse for display in response to driving conditions of said matrix panel in a display period, and supplies, by switching, a column detecting pulse for coordinate detection having a constant amplitude in a detection period, regardless of driving conditions of said display period;

a drive power circuit which supplies voltage at a level required for driving said column electrodes and row electrodes to said column electrode drive circuit and said row electrode drive circuit;

a detection electrode for detecting scanning signals for detection applied to said row electrodes and said column electrodes by electrically coupling said row electrodes and said column electrodes with electrostatic coupling capacity;

a multiplication circuit for multiplying coordinates obtained as the positional information by said coordinate detection circuit and for outputting detection coordinates for each x, y position of the matrix panel; and

a control circuit for controlling said matrix panel, said row electrode drive circuit, said column electrode drive circuit, said drive power circuit, said multiplication circuit and said detection electrode;

wherein said row electrodes are disposed at right angles to said column electrodes.

22. The display-integrated coordinate input device as in claim 21, wherein the scanning pulse for detection has an amplitude higher than maximum amplitude of a driving pulse in a display period.

23. The display-integrated coordinate input device as in claim 21, wherein the column electrode drive circuit comprises selection circuit, which outputs by selecting driving voltage for detection in a display period, and a driving power source;

and wherein the row electrode drive circuit comprises a selection circuit, which outputs by selecting a driving voltage for detection in a display period, and a driving power source.

24. The display-integrated coordinate input device as in claim 21, wherein the matrix panel comprises column electrodes arranged in a first predetermined direction on a first glass substrate at a first predetermined pitch, and row electrodes arranged in a second predetermined direction, which is at a right angle to said first predetermined direction, on a second glass substrate at a second predetermined pitch;

wherein said second glass substrate is disposed so as to face said first glass substrate through the display element, formed as a layer of a display material;

wherein said column electrodes and said row electrodes are led to a sealing section in a non-display area with no bending points, while maintaining said first predetermined pitch and said second predetermined pitch respectively; and

wherein said non-display area is an area not including a display area where at least said column electrodes and said row electrodes are laminated to each other.

25. The display-integrated coordinate input device as in claim 21, wherein the matrix panel comprises column electrodes arranged in a first predetermined direction on a first glass substrate at a first predetermined pitch, row electrodes arranged in a second predetermined direction, which is at a right angle to said first predetermined direction, on a second glass substrate at a second predetermined pitch, leading electrodes disposed in a nondisplay area and a conductive film which is applied on said leading electrodes so as to electrically shield said leading electrodes;

wherein said second glass substrate is disposed so as to face said first glass substrate through the display element, formed as a layer of a display material; and

wherein said non-display area is an area not including a display area where at least said column electrodes and said row electrodes are laminated to each other.

26. The display-integrated coordinate input device as in claim 21, wherein the matrix panel is a liquid crystal panel.