Display-integrated type tablet device

• US 5,825,345 A
• Filed: 08/01/1996
• Issued: 10/20/1998
• Est. Priority Date: 08/02/1995
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Takahama, Kengo, Nozaki, Kiyohiro, Tagawa, Takao
• Primary Examiner(s): Tung, Kee M.
• Assistant Examiner(s): Luu, Matthew
• Application Number:
  US08/690,788
• Time in Patent Office: 810 Days
• Field of Search: 345/104, 345/173, 345/174, 178/18, 178/19
• US Class Current: 345/104
• 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
• 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 2310/0205 Simultaneous scanning of several lines in flat panels

Abstract

During a display period (Y-coordinate detection period), an image is written to an electro-optical material so as to form a display by driving row electrodes and column electrodes by using a row-electrode driving circuit and a column-electrode driving circuit so as to selectively operate TFTs. In this case, a shift data signal having a width corresponding to two clocks of a horizontal sync signal is supplied to the row-electrode driving circuit by using a start-pulse-width expanding circuit; therefore, two row-electrode scanning signals are simultaneously inputted to two of the corresponding row electrodes. Moreover, the row-electrode scanning signals have periods in which they instantaneously turn "off" respectively, and the turning-off timing is coincident in the respective signals. Since a Y-coordinate detection signal is detected in this manner, it becomes possible to increase an induced voltage to be exerted in a detection electrode of an electronic pen, to improve the S/N ratio of the Y-coordinate detection signal, and also to enhance the detection accuracy of the Y-coordinate.

Claims

1. A display-integrated type tablet device comprising:

a pair of transparent substrates that are placed face to face with each other with an electro-optical material being interpolated in between;

a plurality of first electrodes that are disposed on one surface of the transparent substrate in parallel with one another;

a plurality of second electrodes that are disposed in parallel with one another in a manner orthogonal to the first electrodes;

a plurality of switching elements, each being disposed at an intersecting position between the corresponding first and second electrodes and connected to the corresponding first and second electrodes;

a plurality of pixel electrodes that are disposed in a matrix form, each being connected to the corresponding switching elements;

first and second electrode driving means for driving the first and second electrodes;

input means that is electrostatically coupled with the first and second electrodes;

first positional-information detection means which, during a display period in which an image is written to the electro-optical material and a resulting display is made by selectively operating the switching elements by allowing the first and second electrode driving means to drive the first and second electrodes, detects first positional-information that indicates an input position by the input means when the first electrodes are driven; and

second positional-information detection means which, during a period except for the display period, detects second positional-information that indicates an input position by the input means when the second electrodes are driven,

wherein the first electrode driving means, upon driving the first electrodes, outputs scanning signals so that a potential change is exerted in each of the first electrodes so as to detect the first positional-information, and also inputs the scanning signals to the corresponding first electrodes so that a potential change is simultaneously generated in at least two of the first electrodes, the scanning signal being provided with a transfer speed for scanning only the electrode-to-electrode distance corresponding to one of the first electrodes per unit time of a basic clock for driving the first electrode driving means.

2. The display-integrated type tablet device as defined in claim 1, wherein:

the first electrode driving means is provided with;

a sequential output section that generates driving signals for displaying images, and that sequentially outputs the driving signals to the first electrodes so that the driving signals to be applied to at least two of the first electrodes have an overlapped time with each other; and

a gate section that is connected to the sequential output section, and that generates the scanning signal for detecting the first positional information by blocking one portion of the driving signal with a predetermined timing for a period of time that allows the first electrode to have a change in electric potential.

3. The display-integrated type tablet device as defined in claim 2, further comprising:

pulse-width expanding means that expands and converts a signal having the first pulse width into a display-controlling signal having the second pulse width wider than the first pulse width while synchronizing with the reference signal that indicates the start of the display period, and that inputs the display-controlling signal to the first electrode driving means; and

delay means that delays image data by the overlapped time of the driving signals so as to input the resulting image data into the second electrode driving means,

wherein the first electrode driving means generates driving signals for displaying images in accordance with the display-controlling signal.

4. The display-integrated type tablet device as defined in claim 2, further comprising:

control means that controls the first positional-information detection means in such a manner that the first positional-information detection means allows the signal for obtaining the first positional information to pass for a period of time longer than the time during which the gate section blocks the one portion of the driving signal.

5. The display-integrated type tablet device as defined in claim 2, further comprising:

an opposing electrode that is placed face to face with the first and second electrodes; and

opposing electrode driving means that, during the driving period of the first electrodes, inverts the polarity of electric potential of the opposing electrode in synchronism with a horizontal sync signal having a cycle corresponding to one horizontal screen display period,

wherein an induced voltage is exerted in the input means in response to the polarity inversion.

6. The display-integrated type tablet device as defined in claim 5, wherein the operation by which the gate section blocks one portion of the driving signal is carried out during a period other than the transitional response time of the induced voltage responsive to the polarity inversion.

7. The display-integrated type tablet device as defined in claim 5, further comprising:

means for detecting whether the input means is located in the proximity of the transparent substrate in accordance with the inducted voltage responsive to the polarity inversion.

8. The display-integrated type tablet device as defined in claim 1, wherein:

the first positional-information detection means is provided with a first frequency-transmitting means which extracts a signal from the input means with a predetermined frequency band and a first comparison means which detects the first positional information by comparing the signal that has passed through the first frequency-transmitting means with a threshold value, and

the second positional-information detection means is provided with a second frequency-transmitting means which extracts a signal from the input means with a predetermined frequency band and a second comparison means which detects the second positional information by comparing the signal that has passed through the second frequency-transmitting means with a threshold value.

9. The display-integrated type tablet device as defined in claim 8, wherein the first or second frequency-transmitting means is set so that in the waveform of each signal that has passed through the frequency-transmitting means, the rate of change in the rising time in the vicinity of the threshold value and the rate of change in the falling time in the vicinity of the threshold value have absolute values that are equal to each other with polarities reversed to each other.

10. The display-integrated type tablet device as defined in claim 8, further comprising:

an opposing electrode that is placed face to face with the first and second electrodes; and

opposing electrode driving means that, during the driving period of the first electrodes, inverts the polarity of electric potential of the opposing electrode in synchronism with a horizontal sync signal having a cycle corresponding to one horizontal screen display period,

wherein the threshold value of the first comparison means is generated in accordance with the induced voltage in response to the polarity inversion that has been exerted in the input means.

11. The display-integrated type tablet device as defined in claim 1, further comprising:

interfering-noise detection means for detecting interfering noise externally merged during a period other than the driving periods of the first and second electrodes.

12. The display-integrated type tablet device as defined in claim 11, wherein the interfering-noise detection means is provided with third frequency-transmitting means for extracting a noise signal with a predetermined frequency band.

13. The display-integrated type tablet device as defined in claim 12, wherein:

the first positional-information detection means is provided with a first frequency-transmitting means which extracts a signal from the input means with a predetermined frequency band and a first comparison means which detects the first positional information by comparing the signal that has passed through the first frequency-transmitting means with a threshold value, and

the second positional-information detection means is provided with a second frequency-transmitting means which extracts a signal from the input means with a predetermined frequency band and a second comparison means which detects the second positional information by comparing the signal that has passed through the second frequency-transmitting means with a threshold value,

wherein the first or second frequency-transmitting means is used as the third frequency-transmitting means.

14. The display-integrated type tablet device as defined in claim 12, wherein:

the first positional-information detection means is provided with a first frequency-transmitting means which extracts a signal from the input means with a predetermined frequency band and a first comparison means which detects the first positional information by comparing the signal that has passed through the first frequency-transmitting means with a threshold value, and

the second positional-information detection means is provided with a second frequency-transmitting means which extracts a signal from the input means with a predetermined frequency band and a second comparison means which detects the second positional information by comparing the signal that has passed through the second frequency-transmitting means with a threshold value,

wherein the frequency characteristics of the first or second frequency-transmitting means is the same as the frequency characteristics of the third frequency-transmitting means.

15. The display-integrated type tablet device as defined in claim 12, wherein the third frequency-transmitting means has a frequency band that is set in accordance with the second positional information.

16. The display-integrated type tablet device as defined in claim 15, wherein the interfering-noise detection means is provided with fourth frequency-transmitting means for extracting a noise signal with a frequency band that is set in accordance with the first positional information.

17. The display-integrated type tablet device as defined in claim 1, wherein the second electrode driving means, upon driving the second electrodes, outputs scanning signals so that a potential change is exerted in each of the second electrodes so as to detect the second positional-information, and also inputs the scanning signals to the corresponding second electrodes so that a potential change is simultaneously generated in at least two of the second electrodes.

18. A display-integrated type tablet device comprising:

a pair of transparent substrates that are placed face to face with each other with an electro-optical material being interpolated in between;

a plurality of first electrodes that are disposed on one surface of the transparent substrate in parallel with one another;

a plurality of second electrodes that are disposed in parallel with one another in a manner orthogonal to the first electrodes;

first and second electrode driving means for driving the first and second electrodes;

input means that is electrostatically coupled with the first and second electrodes;

first positional-information detection means which detects first positional-information that indicates an input position by the input means when the first electrodes are driven;

second positional-information detection means which detects second positional-information that indicates an input position by the input means when the second electrodes are driven; and

interfering-noise detection means for detecting interfering noise externally merged during a period other than the driving periods of the first and second electrodes.

19. A display-integrated type tablet device comprising:

a pair of transparent substrates that are placed face to face with each other with an electro-optical material being interpolated in between;

a plurality of first electrodes that are disposed on one surface of the transparent substrate in parallel with one another;

a plurality of second electrodes that are disposed in parallel with one another in a manner orthogonal to the first electrodes;

first and second electrode driving means for driving the first and second electrodes;

input means that is electrostatically coupled with the first and second electrodes;

first positional-information detection means which detects first positional-information that indicates an input position by the input means when the first electrodes are driven; and

second positional-information detection means which detects second positional-information that indicates an input position by the input means when the second electrodes are driven,

wherein;

the first positional-information detection means is provided with a first frequency-transmitting means which extracts a signal from the input means with a predetermined frequency band and a first comparison means which detects the first positional information by comparing the signal that has passed through the first frequency-transmitting means with a threshold value, and

the second positional-information detection means is provided with a second frequency-transmitting means which extracts a signal from the input means with a predetermined frequency band and a second comparison means which detects the second positional information by comparing the signal that has passed through the second frequency-transmitting means with a threshold value, the first or second frequency-transmitting means being set so that in the waveform of each signal that has passed through the frequency-transmitting means, the rate of change in the rising time in the vicinity of the threshold value and the rate of change in the falling time in the vicinity of the threshold value have absolute values that are equal to each other with polarities reversed to each other.

20. A display-integrated type tablet device comprising:

a pair of transparent substrates that are placed face to face with each other with an electro-optical material being interpolated in between;

a plurality of first electrodes that are disposed on one surface of the transparent substrate in parallel with one another;

a plurality of second electrodes that are disposed in parallel with one another in a manner orthogonal to the first electrodes;

a plurality of switching elements, each being disposed at an intersecting position between the corresponding first and second electrodes and connected to the corresponding first and second electrodes;

a plurality of pixel electrodes that are disposed in a matrix form, each being connected to the corresponding switching elements;

first and second electrode driving means for driving the first and second electrodes;

input means that is electrostatically coupled with the first and second electrodes;

first positional-information detection means which, during a display period in which an image is written to the electro-optical material and a resulting display is made by selectively operating the switching elements by allowing the first and second electrode driving means to drive the first and second electrodes, detects first positional-information that indicates an input position by the input means when the first electrodes are driven;

second positional-information detection means which, during a period except for the display period, detects second positional-information that indicates an input position by the input means when the second electrodes are driven, and

control means for controlling the first positional-information detection means,

wherein;

the first electrode driving means is provided with a sequential output section that generates driving signals for displaying images, and that sequentially outputs the driving signals and a gate section that is connected to the sequential output section, and that generates a scanning signal for detecting the first positional information by blocking one portion of the driving signal with a predetermined timing for a period of time that allows the first electrode to have a change in electric potential, and

the control means controls the first positional-information detection means in such a manner that the first positional-information detection means allows the signal for obtaining the first positional information to pass for a period of time longer than the time during which the gate section blocks the one portion of the driving signal.

21. A display-integrated type tablet device comprising:

a pair of transparent substrates that are placed face to face with each other with an electro-optical material being interpolated in between;

a plurality of first electrodes that are disposed on one surface of the transparent substrate in parallel with one another;

a plurality of second electrodes that are disposed in parallel with one another in a manner orthogonal to the first electrodes;

a plurality of switching elements, each being disposed at an intersecting position between the corresponding first and second electrodes and connected to the corresponding first and second electrodes;

a plurality of pixel electrodes that are disposed in a matrix form, each being connected to the corresponding switching elements;

first and second electrode driving means for driving the first and second electrodes;

input means that is electrostatically coupled with the first and second electrodes;

first positional-information detection means which, during a display period in which an image is written to the electro-optical material and a resulting display is made by selectively operating the switching elements by allowing the first and second electrode driving means to drive the first and second electrodes, detects first positional-information that indicates an input position by the input means when the first electrodes are driven;

second positional-information detection means which, during a period except for the display period, detects second positional-information that indicates an input position by the input means when the second electrodes are driven; and

display control means which generates driving signals for displaying an image, and which also generates a first reference signal that has a cycle equal to the horizontal sync period for image display and that indicates the timing of the polarity inversion of a signal generated in the input means and a second reference signal that has the same cycle as the first reference signal with the different phase therefrom and that indicates the timing for detecting the first positional information so that the phase-difference time of the first and second reference signals is set to be longer than the transitional response time of the signal of the first positional information,

wherein the first electrode driving means is provided with a sequential output section that sequentially outputs the driving signals and a gate section that is connected to the sequential output section and that generates a scanning signal for detecting the first positional information by blocking one portion of the driving signal for a period of time that is equal to the pulse width of the second reference signal so that the first electrode has a change in electric potential.