JP4942678B2 - Touch panel input device and image forming apparatus - Google Patents

Description

  The present invention relates to a touch panel input device and an image forming apparatus.

As is well known, a resistive film analog detection type (4-wire or 7-wire) touch panel faces a display surface (operation surface) of a liquid crystal display panel on which operation buttons are displayed as images with a fine gap. In addition, a pair of resistance films to which a predetermined reference voltage is applied are bonded as a pressure sensor, and the position on the operation surface (operation position) pressed by the user is the resistance of the reference voltage output from the resistance film. It is detected as a pressure (detection voltage). Such a touch panel displays an image of an operation button or the like on the liquid crystal front panel and is paired with a control device that determines the operation position from the detected voltage, thereby collating the operation position with the position of the operation button. A touch panel input device that determines which operation button the user only operates is configured.
For example, Patent Document 1 below discloses a touch panel input device using such a touch panel.

Further, the control device displays an image such as an operation button on the liquid crystal front panel based on prestored image data, and quantizes the detection voltage at a predetermined sampling interval by using an A / D converter, By converting the quantized voltage into detection data (digital signal) according to a predetermined conversion characteristic, the X coordinate and the Y coordinate on the operation surface are determined as the operation position.
JP 2004-094394 A

By the way, in the A / D converter used in the conventional touch panel input device, the conversion characteristic between the detection voltage and the detection data is linear (linear), that is, a constant value regardless of the magnitude of the detection voltage. FIG. 1 is a schematic diagram illustrating conversion of detection voltage into detection data (particularly conversion in the Y-axis direction) by an 8-bit A / D converter. The conversion resolution Δd in the conversion in the Y-axis direction is a constant value regardless of the magnitude of the detection voltage.
That is, although the operation buttons as shown in the figure are displayed on the operation surface of the touch panel, the conventional touch panel input device determines the operation position over the entire operation surface of the liquid crystal panel regardless of the position of the operation button. The resolution is constant.

  However, for example, the voltage range a of the detection voltage including the lower end of the operation button as indicated by the arrow is converted into detection data b that does not correspond to the lower edge of the operation button. There is a problem that even if the lower edge of the button is pressed, it is not determined that the button has been operated, that is, erroneously determined.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to correct erroneous determination caused by the conversion characteristics of an A / D converter.

In order to achieve the above object, the present invention provides a display unit that displays one or a plurality of operation buttons on an operation surface based on a predetermined image signal, as a first solution means for a touch panel input device, A pressure sensor unit that detects the pressed position as a detection signal that is an analog signal, an A / D converter that converts the detection signal input from the pressure sensor unit into detection data that is a digital signal, and the display unit that displays the image signal And a control unit that determines whether or not the operation button is operated based on the detection data input from the A / D converter, and the control unit determines the conversion resolution of the A / D converter on the operation surface. A conversion control signal that is set to a different value according to the position is output, and the A / D converter converts the detection signal into detection data based on the conversion control signal.
Further, as a second solving means relating to the touch panel input device, a means is adopted in which the control unit outputs a conversion control signal for making the conversion resolution close to the edge of the operation button dense to the A / D converter.
Further, in the present invention, as a third solving means related to the image forming apparatus, a means is provided in which the first or second touch panel input device is provided as an operation device.

According to the present invention, the control unit outputs a conversion control signal for variably setting the conversion characteristic of the A / D converter according to the position on the operation surface, and the A / D converter detects based on the conversion control signal. Since the signal is converted into detection data, it is possible to correct the erroneous determination of the control unit that occurs according to the position of the operation button on the operation surface.
In particular, in the case of a conversion control signal that makes the conversion resolution near the edge of the operation button dense, erroneous determination when the vicinity of the edge of the operation button is pressed can be eliminated.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 2 is a block diagram illustrating a functional configuration of the touch panel input device according to the present embodiment. As shown in this figure, the touch panel input device includes a touch panel A and a control unit B. The touch panel A is a resistive film analog detection type (4-wire type or 7-wire type), displays a predetermined operation screen under the control of the control unit B, and displays the user's pressing position on the operation screen as the operation position. To the control unit B.

  The touch panel A includes a liquid crystal display unit a1, a pressure sensor unit a2, and a pair of A / D converters a3 and a4. The liquid crystal display unit a1 has a display surface with a predetermined size, and displays an operation image based on an image signal input from the control unit B. This operation image includes, for example, one or a plurality of operation buttons M1 to M6 as shown in the schematic diagram of FIG. 3, and has a rectangular shape having a predetermined length in the X-axis direction and the Y-axis direction. The operation buttons M1 to M6 are arranged on such a display surface at a predetermined interval.

  The press sensor unit a2 detects an operation position based on the above-described resistance film analog detection method, and outputs an X-axis detection voltage and a Y-axis detection voltage indicating the operation position to the A / D converter a3. That is, the press sensor part a2 is bonded to the display surface (operation surface) and provided with a pair of resistance films opposed to each other with a fine gap, and a direct current power source for applying a predetermined reference voltage to the resistance film, In addition, the circuit includes a circuit that outputs a resistance divided voltage of the reference voltage obtained when the user presses the surface of the resistance film to come into contact with each other.

  The X-axis detection voltage is obtained by dividing a predetermined reference voltage in accordance with the operation position, and is a voltage signal indicating the X coordinate of the pressed position pressed by the user on the operation surface. The Y-axis detection voltage is a voltage signal indicating the Y coordinate of the pressed position pressed by the user on the operation surface, which is obtained by resistance-dividing the reference voltage according to the operation position. These X-axis detection voltage and Y-axis detection voltage are, for example, smaller values closer to the origin (0, 0) (that is, larger values farther from the origin (0, 0)). That is, the X-axis detection voltage and the Y-axis detection voltage are detection signals (analog signals) that indicate the X-axis coordinate and the Y-axis coordinate of the operation position based on the voltage value.

  The A / D converter a3 is an electronic circuit that converts the X-axis detection voltage, which is an analog signal, into X-axis detection data, which is a digital signal. Conversion characteristics from voltage to X-axis detection data are variably set. The A / D converter a4 is an electronic circuit that converts the Y-axis detection voltage, which is an analog signal, into Y-axis detection data, which is a digital signal. The A / D converter a4 is based on the conversion control signal input from the control unit B. The conversion characteristics from the axis detection voltage to the Y axis detection data are set to different values.

  The control unit B outputs an image signal indicating the operation image to the liquid crystal display unit a1, and any one of the operation buttons M1 to M6 displayed on the operation surface based on the X-axis detection data and the Y-axis detection data. It is determined whether an operation has been instructed, and is output to the outside as operation information. The control unit B also sends a conversion control signal for setting the conversion characteristics of the A / D converters a3 and a4 to different values according to the position (XY coordinate) on the operation surface. Output to a3 and a4.

  Next, the operation of the touch panel input device configured as described above will be described in detail with reference to FIGS.

  In the touch panel input device, a predetermined operation image is displayed on the display surface (operation surface) based on the image signal output from the control unit B to the liquid crystal display unit a1. In this operation image, a plurality of operation buttons are arranged separately as shown in FIG. 3, and when the user presses the operation button M2, for example, on the operation surface, that is, on the operation surface (display surface). When one of the display areas of the operation button M2 is pressed, the X-axis detection voltage indicating the X coordinate of the pressed position (operating position) is transferred from the press sensor unit a2 to the A / D converter a3, and the pressed position ( The Y-axis detection voltage indicating the Y coordinate of the (operation position) is output from the press sensor unit a2 to the A / D converter a4.

  The X-axis detection voltage is converted to X-axis detection data by the A / D converter a3 and input to the control unit B, and the Y-axis detection voltage is converted to Y-axis detection data by the A / D converter a4. And input to the control unit B. Then, the control unit B determines that the operation button M2 is operated by the user based on the X-axis detection data and the Y-axis detection data input from the A / D converters a3 and a4 in this way. The determination result is output to the outside as operation information.

  The above is the basic operation of the touch panel input device. The control unit B outputs conversion control signals to the A / D converters a3 and a4 in advance, thereby converting the X-axis detection voltage into the X-axis detection data. The conversion resolution in the conversion from the Y-axis detection voltage to the Y-axis detection data is set to a different value depending on the position on the operation surface.

  That is, as shown in FIG. 4, the value of the detection voltage (X-axis detection voltage and Y-axis detection voltage) indicates a position (XY coordinate) on the operation surface (XY plane). B sets the conversion characteristics so that the conversion resolution Δd2 of the detection voltage corresponding to the region near the edge of the operation button is denser (narrower) than the conversion resolution Δd1 of other regions. Although only the Y-axis direction is shown in FIG. 4, the control unit B similarly has a higher conversion resolution than the other regions for the detection voltage corresponding to the region near the edge of the operation button in the X-axis direction ( Set the conversion characteristics to be narrower.

  According to such a touch panel input device as described above, the conventional problems are solved and erroneous determination is eliminated. That is, since the conversion resolution Δd2 of the detection voltage corresponding to the region near the edge of the operation button is denser (narrower) than the conversion resolution Δd1 of the other region, the operation is performed when the user presses the edge of the operation button. It can be resolved that the button is not pressed. Therefore, this touch panel input device has better operability as a man-machine interface than a conventional touch panel input device.

  Such a touch panel input device can be applied as an operation device to an image forming apparatus such as a copier, a printer, a facsimile, or a multifunction peripheral having all the functions of these devices. In such an image forming apparatus, a touch panel input device is conventionally used as an operation device, but comfortable operability can be realized by employing the touch panel input device.

  In addition, this invention is not limited to the said embodiment, For example, the following modifications can be considered.

(1) Although the press sensor part a2 of the above embodiment detects the operation position based on the resistance film analog detection system, the present invention is not limited to the anti-film analog detection system pressure sensor. The present invention is characterized in that the conversion resolution of the A / D converter differs depending on the detection voltage region, and therefore the analog detection voltage is converted into digital detection data regardless of the method of the press sensor. The present invention can be applied to any device that converts the data into the device.

(2) In the above embodiment, the conversion resolution Δd2 of the detection voltage corresponding to the region near the edge of the operation button is closer (narrower) than the conversion resolution Δd1 of other regions, that is, two different conversion resolutions Δd1 and Δd2. However, the present invention is not limited to this. The number of different conversion resolutions may be three or more as required.

(3) Further, the touch panel input device can be applied to input devices of various electronic devices in addition to the operation device of the image forming apparatus described above. In particular, the present invention is suitable when many operation buttons are arranged densely on the operation surface.

It is a schematic diagram for demonstrating the technical subject of this invention. It is a block diagram which shows the function structure of the touchscreen input device concerning one Embodiment of this invention. It is a schematic diagram which shows the operation surface (display surface) of the touchscreen input device concerning one Embodiment of this invention. It is a schematic diagram which shows the effect | action of the touchscreen input device concerning one Embodiment of this invention.

Explanation of symbols

  A ... Touch panel, a1 ... Liquid crystal display part, a2 ... Press sensor part, a3, a4 ... A / D converter, B ... Control part

Claims (2)

A display unit that displays one or more operation buttons on the operation surface based on a predetermined image signal;
A pressing sensor unit that detects a pressing position on the operation surface as a detection signal that is an analog signal;
An A / D converter that converts the detection signal input from the pressure sensor unit into detection data that is a digital signal;
A control unit that supplies the image signal to the display unit and determines whether or not the operation button is operated based on detection data input from the A / D converter;
The control unit outputs a conversion control signal for finely setting a conversion resolution in the vicinity of the edge of the operation button to the A / D converter ;
The A / D converter converts a detection signal into detection data based on the conversion control signal. An image forming apparatus comprising the touch panel input device according to claim 1 as an operation device.

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