JPH07302168A - Touch panel input device - Google Patents

Abstract

(57) [Abstract] [Object] The present invention increases power consumption in a touch panel input device which is provided on a display screen of an electronic information device and is used to obtain coordinates on the screen according to a pressed position. The purpose is to detect the input position with high accuracy without performing the above operation. [Structure] In a touch panel 12 arranged on a display screen of a liquid crystal display unit 17, an applied voltage E is applied from a CPU 11 to a touch panel 12 by a power source selector 20, and a high voltage power source 18 (5 V) is used in a handwriting input mode. In the touch key input mode of selecting and applying and touching the keyboard displayed on the display screen to input, select and apply the low voltage power source 19 (3V) to detect the touch position from the touch panel 12. On the display screen, the change width of the voltage Vout is adjusted as necessary, and the position detection voltage Vout is digitally converted into 16 bits in the case of handwriting input and 10 bits in the case of touch key input. X
Convert to Y coordinate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a touch panel input device provided on a display screen of an electronic information device such as an electronic notebook and used to obtain coordinates on the screen corresponding to the pressed position.

[0002]

2. Description of the Related Art In recent years, in electronic information devices such as an electronic notebook and a pocket computer, a touch panel type input device provided so as to overlap the display screen has been used, and a menu or keyboard displayed on the screen can be directly touched. You can perform input operations and display characters and figures by handwriting.

FIG. 4 is a diagram showing the structure of a resistive film type panel which is one of such touch panel systems. The touch panel is provided with an upper-layer resistance film RS1 and a lower-layer resistance film RS2 corresponding to the display area of the display screen in a laminated manner. For example, the upper-layer resistance film RS1 is provided with a voltage E in the X direction and the lower-layer resistance film RS2 is provided with Y. The voltage E is alternately applied in the direction, and when a certain point of the upper resistance film RS1 is pressed,
When the voltage E is applied to the upper resistance screen RS1,
A voltage signal Vx which is resistance-divided in the X direction of the upper film RS1.
out is derived from the lower resistance film RS2, and the lower resistance film R
At the timing when the voltage E is applied to S2, the voltage signal Vyout which is resistance-divided in the Y direction of the lower resistance film RS2 is derived from the upper resistance curtain RS1.

That is, the voltage signals Vx out and Vy out derived from the resistance films RS1 and RS2 serve as pressing position information on the touch panel in the X and Y directions, respectively, and the voltage signals Vx out and Vy are used. ou
The input coordinates on the display screen are detected by A / D converting t and converting it into XY coordinates.

[0005]

In such a touch panel, the variation width of the detection voltage Vout accompanying the movement of the pressing position with respect to the touch panel is large when the voltage level of the applied voltage E is high and is small when the voltage level of the applied voltage E is low. Therefore, especially when the applied voltage E is set to be low, there is a drawback that the change of the detection voltage Vout is easily hidden by the inclusion of noise or the like.

Therefore, considering the occurrence of noise, when the detected voltage Vout is A / D converted and converted into XY coordinates on the display screen, the reliability of the lower digit of the digital value becomes poor,
It cannot be used as a highly accurate coordinate value.

Therefore, in order to obtain the pressure detection position of the touch panel with high accuracy, the applied voltage E is increased and the detection voltage V is increased.
Although it is necessary to increase the change width of out, there is a problem that power consumption increases.

The present invention has been made in view of the above problems,
An object of the present invention is to provide a touch panel input device capable of performing highly accurate input position detection without increasing power consumption.

[0009]

That is, a first touch panel input device according to the present invention is provided corresponding to a display unit and a display screen of the display unit, and an applied voltage is applied to a pressing position of the display screen. A touch panel for resistance-dividing and outputting in accordance with the voltage, a voltage applying unit for applying a voltage to the touch panel, and a voltage applied to the touch panel by the voltage applying unit for the case of handwriting input and the keys displayed on the display screen. It is configured to include a voltage changing unit that changes the touch voltage input by touching and inputting, and an A / D converting unit that A / D converts the output voltage from the touch panel.

In a second touch panel input device according to the present invention, the voltage applying means has at least two power supplies, and the voltage changing means selects one power supply from the voltage applying means. And the A / D
The converting means is configured to execute the A / D conversion with different resolution according to the power source selected by the voltage changing means.

In the third touch panel input device according to the present invention, the voltage changing means sets a high voltage for handwriting input and a low voltage for touch key input.

[0012]

That is, in the touch panel input device, the voltage applied to the touch panel by the voltage applying means is selected and applied by the high voltage power source in the case of handwriting input, and the key displayed on the display screen is touched. In the case of touch key input, the low voltage power source is selected and applied, and further, in the case of handwriting input, the A / D conversion resolution is high, and in the case of touch key input, it is set low. If necessary, the input position detection accuracy can be switched.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of an electronic circuit of an electronic notebook equipped with the touch panel input device of the present invention.

This electronic notebook is a central processing unit (CPU).
11 is provided. The CPU 11 loads a system program stored in advance according to a touch position detection signal supplied from the touch panel 12 via the panel control unit 13 and the 10-bit A / D conversion unit 14 or the 16-bit A / D conversion unit 15. The CPU 11 is activated and controls the operation of each part of the circuit.
4, 15, a liquid crystal display unit (LCD) 17 is connected via a display drive circuit 16, and the touch panel 12
High voltage power supply (5V) 18 and low voltage power supply (3V) 19
A power source selector 20 that selects one of the two is connected.

The touch panel 12 has a touch input area corresponding to the display screen area of the liquid crystal display unit 17, and is arranged so as to overlap the display screen.
One power supply voltage E selected by the power supply selector 20 is applied to the upper resistance film RS1 and the lower resistance film RS2 (see FIG. 4) through the panel control unit 13 and is also output from the touch panel 12. Touch position detection voltage Vo
ut is converted into a digital value by the 10-bit A / D conversion unit 14 and the 16-bit A / D conversion unit 15 via the panel control unit 13, and is supplied to the CPU 11.

In this case, the CPU 11 uses the XY coordinates of the liquid crystal display unit 17 to obtain the digital value corresponding to the touch position of the touch panel 12 supplied from the 10-bit A / D conversion unit 14 or the 16-bit A / D conversion unit 15. The CPU 11 determines the touch position on the display screen.

Here, the power source selector 20 is a CPU.
The control signal from 11 selects the high voltage power supply 18 in the handwriting input mode for the display screen, and selects the low voltage power supply 19 in the touch key input mode for touching and inputting the key displayed on the display screen. The input mode is switched by touching the menu screen displayed on the liquid crystal display unit 17.

Then, in the handwriting input mode in which the applied voltage E from the high voltage power source 18 is applied to the touch panel 12, the 16-bit A / D conversion unit 15 A / D-converts the digital value of the liquid crystal display unit 17 according to the digital value. In the touch key input mode in which the XY coordinates are converted and the applied voltage E from the low voltage power source 19 is applied to the touch panel 12,
The XY coordinates of the liquid crystal display unit 17 are converted according to the digital value A / D converted by the 10-bit A / D conversion unit 14.

Next, the operation of the touch panel input device having the above structure will be described. FIG. 2 is a flowchart showing a panel control process in an electronic notebook equipped with the touch panel input device.

FIG. 3 is a diagram showing a touch input state accompanying a panel control process of an electronic notebook equipped with the touch panel input device. FIG. 3A is a diagram showing an input state in a handwriting input mode. (B) is a diagram showing an input state in the touch key input mode.

That is, as shown in FIG. 3A, when the handwriting input mode is set by touching the menu screen displayed on the liquid crystal display unit 17, the high voltage power supply 18 is turned on by the power supply selector 20. The selected voltage E of 5V is supplied to the touch panel 12 via the panel controller 13 (steps S1 → S2).

When a handwriting input such as a map is made on the touch panel 12, the touch position detection voltage Vout from the touch panel 12 is digitally converted by the panel control section 13 via the 16-bit A / D conversion section 15. 16
CP as a digital value indicating the panel touch position with a bit
This is taken in by U11, whereby the CPU 11 converts the XY coordinates of the liquid crystal display unit 17 according to the digital value indicating the touch position which is A / D converted by the 16 bits, and the liquid crystal display along the handwriting input position is displayed. The process is executed (step S3).

In this case, as the touch position detection voltage Vout output from the touch panel 12, the applied voltage of 5V applied from the high voltage power source 18 selected through the power source selector 20 is output by resistance division. Compared to the case where the low-voltage power supply 19 is selected, the change width of the touch position detection voltage Vout accompanying the movement of the touch position becomes large, and accurate position detection can be performed.

Moreover, the touch position detection voltage Vout
Are 16-bit A / D converted and XY of the liquid crystal display unit 17
Since it is converted into coordinates, high-precision handwriting input can be performed.

On the other hand, for example, in the setting state of the handwriting input mode, as shown in FIG.
By touching the menu screen displayed in 7,
When the touch key input mode is set, the CPU 11 displays a keyboard on the liquid crystal display unit 17, the power source selector 20 selects the low-voltage power source 19, and 3V is selected.
Is applied to the touch panel 12 via the panel control unit 13 (steps S4 → S5).

When an input operation is performed on the touch panel 12 with respect to the keyboard displayed on the liquid crystal display unit 17, the touch position detection voltage Vout from the touch panel 12 is input.
Is from the panel controller 13 to the 10-bit A / D converter 14
It is digitally converted via 10 and is taken in by the CPU 11 as a digital value indicating the panel touch position in 10 bits.
The XY coordinates of the liquid crystal display unit 17 are converted according to the digital value indicating the touch position that has been D / D converted, and the input key recognition processing for the keyboard is executed (step S).
6).

In this case, since the touch position detection voltage Vout output from the touch panel 12 is the resistance applied to the voltage of 3V applied from the low voltage power source 19 selected via the power source selector 20, the touch position detection voltage Vout is output. Compared with the case where the high-voltage power supply 18 is selected, the change width of the touch position detection voltage Vout accompanying the movement of the touch position is small, but each key of the keyboard displayed on the liquid crystal display unit 17 is small. Since each has a certain amount of area, the variation range of the touch position detection voltage Vout for each key can be sufficiently obtained, and accurate key input processing can be performed even if the A / D conversion value is 10 bits. Like

Thereafter, depending on whether the setting mode is the handwriting input mode or another mode such as the touch key input mode, the applied voltage E to the touch panel 12 is set to the high voltage power source 18 by the power source selector 20. , Or the low-voltage power supply 19, the liquid crystal display unit 1
The high-voltage power supply 18 is used only when high-precision position input is required for 7 to prevent an increase in power consumption (steps S7 → S1).

Therefore, according to the electronic notebook equipped with the touch panel input device having the above-mentioned configuration, in the touch panel 12 arranged so as to overlap the display screen of the liquid crystal display unit 17,
Touch panel 1 from CPU 11 by power source selector 20
In the handwriting input mode, the high voltage power supply 18 (5V) is selected and applied to the applied voltage E for 2 in the handwriting input mode, and in the touch key input mode in which the keyboard displayed on the display screen is touched for input. Is the low voltage power source 19 (3
V) is selected and applied to adjust the variation width of the touch position detection voltage Vout from the touch panel 12 as necessary, and in the case of handwriting input, the position detection voltage Vou is applied.
t is digitally converted into 16 bits, and in the case of touch key input, it is digitally converted into 10 bits and XY on the display screen
Since the coordinates are converted, it is possible to handle a highly accurate input operation without increasing the power consumption.

[0030]

As described above, according to the present invention, the voltage applied to the touch panel by the voltage applying means is, for example, in the case of handwriting input, the high voltage power source is selected and applied, and is displayed on the display screen. In case of touch key input, a low voltage power supply is selected and applied, and further, A / D conversion resolution is high in the case of handwriting input and low in the case of touch key input. Since the setting is made, the input position detection accuracy can be switched if necessary. Therefore, it is possible to detect the input position with high accuracy without increasing the power consumption.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an electronic circuit of an electronic notebook equipped with a touch panel input device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing panel control processing in an electronic notebook equipped with the touch panel input device.

FIG. 3 is a diagram showing a touch input state associated with a panel control process of an electronic notebook equipped with the touch panel input device, and FIG. 3A is a diagram showing an input state in a handwriting input mode; ) Is a diagram showing an input state in the touch key input mode.

FIG. 4 is a diagram showing a configuration of a touch panel.

[Explanation of symbols]

11 ... Central processing unit (CPU), 12 ... Touch panel,
13 ... Panel control unit, 14 ... 10-bit A / D conversion unit,
15 ... 16-bit A / D converter, 16 ... Display control circuit,
17 ... Liquid crystal display (LCD), 18 ... High-voltage power supply, 19
... low-voltage power supply, 20 ... power supply selector, RS1, ... upper resistance film, RS2 ... lower resistance film.

Claims (3)

[Claims] 1. A display unit, a touch panel which is provided corresponding to a display screen of the display unit, and which outputs an applied voltage by resistance division according to a pressing position of the display screen, and a voltage is applied to the touch panel. Voltage applying means and voltage changing means for changing the voltage applied to the touch panel by the voltage applying means between handwriting input and touch key input by touching a key displayed on the display screen. , A / D for A / D converting the output voltage from the touch panel
A touch panel input device comprising: a D conversion means. 2. The voltage applying means has at least two power sources, the voltage changing means selects one power source from the voltage applying means, and the A / D converting means has the voltage changing means. The touch panel input device according to claim 1, wherein the A / D conversion is executed with different resolution according to the power source selected by. 3. The touch panel input device according to claim 1, wherein the voltage changing unit sets a high voltage for handwriting input and a low voltage for touch key input. .