JPH1165744A - Inputting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely and stably specify only an input position at which an incident light is completely shielded. SOLUTION: Each photodiode cell provided at an area sensor 2 outputs a current corresponding to a bias voltage and an incident light illuminance, and the current is converted into a voltage, and applied to a programmable gain amplifier 13 as illuminance. A compensation value calculating part 10 selects, from a compensation data ROM 9, a gain and offset voltage corresponding to an outside environment condition detected by an environment sensor 7. The selected gain and offset voltage are set at the programmable gain amplifier 13, which amplifies the illuminance from the sensor 2, and compensates it with the set gain and offset value. The corrected illuminance is binarized by a binarizing part 6, a featuring position is calculated by a featuring position calculating part, thus an input position is determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an input device for specifying an input position according to the illuminance of light incident on a light receiving element cell.

[0002]

2. Description of the Related Art A conventional electronic device capable of inputting data from a touch panel is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-152010. For example, in an optical touch panel, an input position is detected by irradiating a light beam in a lattice shape and blocking the light beam with an operator's finger or a predetermined input pen. In place of such a method of irradiating a light beam, a conventional device for detecting an input position using a photocell is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-50342. In that publication, photovoltaic cells are sequentially selected by a scanning circuit. In the selected photovoltaic cell, the generated photovoltaic power is amplified and output. A predetermined bias voltage is applied to the unselected photocells, thereby preventing the function as the photocell. In this way, only the photovoltaic power from the desired photovoltaic cell is detected.

[0003]

The problem to be solved by the present invention is disclosed in Japanese Patent Laid-Open No. 9-503.
No. 42, when a device using a photovoltaic cell is used as a touch panel, light incident on the photovoltaic cell is blocked by an operator's finger or an input pen, and when an attempt is made to detect a blocked specific coordinate point, the light is completely blocked. Not only the specified coordinate point but also a coordinate point on which scattered light enters from outside as a shadow of a finger or an input pen may be determined as a specific coordinate point, that is, an input position. Further, the electromotive force output from each photovoltaic cell is variable according to the temperature and the illuminance, and therefore, depending on the external environment state such as the external temperature and the illuminance of the external light, an undesired coordinate point may be determined as the input position. There is. As described above, in the apparatus of the related art, there is a disadvantage that, in actual use, only the input position where the incident light is completely blocked cannot be reliably and stably specified.

An object of the present invention is to provide an input device that can reliably and stably specify only an input position where incident light is completely blocked.

[0005]

The present invention comprises a plurality of light receiving element cells arranged in a matrix, and a current value corresponding to a bias voltage applied to each element and an illuminance of incident light is applied to each element. And an input position determining unit for determining an input position based on the obtained illuminance. An input device characterized by the following.

According to the present invention, each light receiving element cell to which a bias voltage is applied outputs a current value corresponding to the illuminance of the incident light. , Different light values are output from the specific cell and the other cells.
Illuminance according to the output current value is obtained for each cell,
The input position is determined based on the obtained illuminance. Therefore, the input position can be reliably specified from the position of the specific light receiving element cell where the incident light is shielded.

Further, according to the present invention, the input position determining means includes:
A binarizing unit for binarizing each illuminance obtained by the illuminance obtaining unit is provided, and an input position is determined from a light receiving element cell position of the binarized illuminance of 0 or 1.

According to the present invention, the obtained illuminance is binarized. For example, the illuminance of a specific light receiving element cell that is completely shielded from light is set to 0, and the illuminance of other light receiving element cells is set to 1. Some current values are output from the light-receiving element cells that become the shadow of the operator's finger or input pen and are scattered, but incident light is completely blocked by selecting the threshold value for binarization processing as appropriate. The specified specific light receiving element cell can be distinguished from the other light receiving element cells, and the input position can be reliably specified from the position of only the specific light receiving element cell.

The present invention also provides an external environment state obtaining means for obtaining the external environment state of the input device, and a correction means for correcting the illuminance obtained by the illuminance obtaining means based on the obtained external environment state. Wherein the input position determining means determines an input position based on the corrected illuminance.

According to the present invention, the external environment state of the input device is obtained, the illuminance is corrected based on the obtained external environment state, and the input position is determined based on the corrected illuminance. Although the characteristics of the light receiving element cell fluctuate depending on the external environment state such as the external temperature and the illuminance of the external light, the input position can be stably specified regardless of the external environment state by the above-described correction.

Further, according to the present invention, the input device includes storage means for storing a correction condition predetermined for each external environment state, and the correction means stores the external environment state acquired by the external environment state acquisition means. It is characterized in that a corresponding correction condition is selected from the storage means, and the illuminance is corrected based on the selected correction condition.

According to the present invention, the correction of the illuminance based on the external environment state is specifically performed under the correction condition selected according to the acquired external environment state. The input position can be stably specified based on the illuminance corrected in this manner regardless of the external environment state.

[0013]

FIG. 1 is a block diagram showing an electrical configuration of an input device 1 according to one embodiment of the present invention. The area sensor 2 includes a plurality of photodiode cells configured as described below. The area sensor 2 is driven and controlled by an area sensor driver 3, and a bias voltage according to a clock signal is applied to each cell. Each cell outputs a current value according to the illuminance of incident light. The output current value is converted into a voltage value, and is supplied to the programmable gain amplifier 13 as illuminance. In the programmable gain amplifier 13, the illuminance is amplified and corrected according to the external environment state as described later. The A / D (analog / digital) converter 4 converts an analog output voltage from the programmable gain amplifier 13 into a digital value and supplies the digital value to the binarization unit 6.

The binarizing section 6 binarizes the corrected illuminance. The instruction of the area sensor 2 by the operator's finger, a predetermined input pen, or the like is performed in such a manner as to completely block the light incident on the area sensor 2, so that the illuminance distribution of the area sensor 2 is determined by the external light irradiation area, The region is divided into three regions: a region where the light is scattered from the periphery as a shadow of the finger and the input pen and a region where the light is completely blocked by the finger and the input pen. By setting the threshold value for binarization between the illuminance of the scattered light irradiation area serving as a shadow and the illuminance of the complete light shielding area, the external light irradiation area and the scattered light irradiation area serving as a shadow are set to one.
And the complete light shielding area can be set to 0. By performing such binarization processing by setting such a threshold value,
Only the complete light shielding area can be divided from the two areas. The characteristic position calculation unit 5 extracts the characteristic position of the complete light-shielded area divided by the binarization processing, determines an input position, and outputs the input position.

The environment sensor 7 measures and detects the external environment state of the input device 1, for example, the external temperature and the illuminance of external light. Since the characteristics of each photodiode cell included in the area sensor 2 change depending on the temperature, the external temperature is measured to correct the variation due to the external temperature. Further, since the dynamic range of the output voltage of the area sensor 2 changes depending on the illuminance of the incident light, the external light illuminance is measured in order to correct the variation due to the external light illuminance. The temperature and the illuminance of the analog value detected by the environment sensor 7 are converted into a digital value by the A / D converter 8 and
0 is given. In order to correct the illuminance from the area sensor 2 according to the external environment state detected by the environment sensor 7, the input device 1 includes a compensation data ROM (read only memory) for storing a correction condition for each photodiode cell. 9 is provided. Specifically, the compensation data ROM 9 stores a gain and an offset voltage as characteristics of each cell for each external environment state. The compensation value calculation unit 10 selects a gain and an offset voltage according to the external environment state detected by the environment sensor 7 from the compensation data ROM 9.

The gain of the digital value selected by the compensation value calculator 10 is determined by the D / A (digital / analog) converter 1
The value is converted to an analog value by 1 and given to the programmable gain amplifier 13 to be set as a gain for correction.
The digital value offset voltage selected by the compensation value calculation unit 10 is converted into an analog value by the D / A converter 12, supplied to the programmable gain amplifier 13, and set as a correction offset voltage. The programmable gain amplifier 13 amplifies the illuminance from the area sensor 2 and corrects the illuminance with the set gain and offset voltage.

FIG. 2 is a circuit diagram showing the area sensor 2. The area sensor 2 includes a plurality (16 in this embodiment) of photodiode cells 15 and a plurality (4 in this embodiment).
It includes a plurality of row line wirings 16, a plurality of (four in the present embodiment) column line wirings 17, a switching unit 18, and an amplifier 19. The row line wirings 16 are arranged in parallel with a space between each other, and the column line wirings 17 are similarly arranged in parallel with a space between each other. The row line arrangement 16 and the column line wiring 17 are arranged to be orthogonal to each other,
A rectangular area formed by the wirings 16 and 17 includes:
For example, photodiode cell 1 realized by a-Si
5 are respectively arranged. Thus, the photodiode cells 15 are arranged in a 4 × 4 matrix.
The switching unit 18 is realized by a plurality (four in this embodiment) of analog switches for individually selecting each row line wiring 16. The selected row line wiring 16 is connected to the amplifier 19, and the unselected row line wiring 16 is grounded.

FIG. 3 shows bias voltages VB1 to VB supplied from the area sensor driver 3 to each column line wiring 17.
FIG. As shown in FIG. 3A, the bias voltage VB1 supplied to the first column line wiring 17 depends on the amount of current passing through the photodiode cells 15 on the line 17 (the amount of leakage current) depending on the illuminance. Almost 0 (zero)
Is a rectangular wave that has a predetermined lower limit value V2 in a period from a predetermined time t1 to a time t2 according to the clock signal, with the voltage value that becomes the upper limit value V1. Bias voltages VB2 to VB supplied to the second to fourth column line wirings 17
B4 is the same as the bias voltage VB1 shown in FIGS.
As shown in (D), the voltage values at which the amount of current passing through the photodiode cell 15 on each line 17 becomes almost zero regardless of the illuminance are defined as upper limit values V3, V5, and V7, and predetermined values corresponding to the clock signal are set. In the period from time t2, t3, t4 to time t3, t4, t5, the predetermined lower limit value V4,
The rectangular waves are V6 and V8.

The bias voltages VB1 to VB4 are sequentially applied to the column line wirings 17 so that the column line wiring 1
7, and the analog switches of the switching unit 18 are sequentially switched to scan the row line wiring 16, thereby obtaining output currents from the cells 15 according to the illuminance of incident light. The output current is amplified by the amplifier 19 and output from the area sensor 2 as a voltage value.

In this embodiment, the example of the 4 × 4 photodiode cell 15 has been described. However, the number of the cells 15 is not limited to this, and is, for example, 640 × 4.
It may be 480.

FIG. 4 is a diagram for explaining the operation of the characteristic position calculating section 5, and is a diagram showing a complete light shielding area A2 in the daylighting area A1 of the area sensor 2. The complete light shielding area A2
Indicates a state after binarization by the binarization unit 6. An orthogonal coordinate system is set in advance in the lighting area A1 of the area sensor 2, and the feature position calculation unit 5 determines that the horizontal start position HL, the horizontal end position HH, the vertical start position VL, and the vertical start position HL of the complete light shielding area A2. The vertical end position VH is detected. Next, the horizontal length HS is obtained from the difference between HH and HL, and the vertical length VS is obtained from the difference between VH and VL, and light is shielded by the finger of the operator or the input pen. It is determined whether the area is an area or an area that has been determined to be shielded by dust or noise.
If the area is shaded by the operator's finger or the input pen, the horizontal coordinate position HC is obtained by HC = (HH + HL) / 2. Further, the vertical coordinate position VC is obtained by VC = (VH + VL) / 2. Then, the coordinate point designated by (HC, VC) is determined as an input position and output. If the area is not shaded by the operator's finger or the input pen, an invalid coordinate point is output as (HC, VC).

FIG. 5 is a flowchart for explaining the input position determining operation of the input device 1. In step a1, the environment sensor 7 measures and detects the external temperature and the external light illuminance as the external environmental state. The detected temperature and illuminance are converted into digital values by the A / D converter 8 and provided to the compensation value calculation unit 10. In step a2, the compensation value calculation unit 10 checks the compensation data ROM 9, and selects a gain and offset voltage for correction according to the detected external temperature and external light illuminance. In step a3,
The gain of the selected digital value is adjusted by the D / A converter 11
Is converted to an analog value, is given to a programmable gain amplifier 13 and is set as a gain for correction, and the offset voltage of the selected digital value is converted to an analog value by the D / A converter 12 and is converted to an analog value. 13 and is set as an offset voltage for correction.

In step a4, a current value corresponding to the illuminance of the light incident on the area sensor 2 is output from each cell 15,
It is converted into a voltage value and given to the programmable gain amplifier 13 as illuminance. In step a5, the programmable gain amplifier 13 corrects the illuminance from the area sensor 2 with the set gain and offset voltage. The output from the programmable gain amplifier 13 is converted into a digital value by the A / D converter 4 and supplied to the binarization unit 6. In step a6, the binarization unit 6 binarizes the corrected illuminance. In step a7, based on the binarized illuminance, the feature position calculation unit 5 extracts a feature position and determines an input position.

As described above, according to the present embodiment, when light incident on the area sensor 2 is blocked by the operator's finger or a predetermined input pen, incident light of the photodiode cells 15 provided in the area sensor 2 is reduced. Different current values are output from a specific cell completely shielded from light and other cells. The current value is converted into a voltage value, the illuminance corresponding to the current value is obtained for each cell 15, and the input position can be determined based on the illuminance. By determining the input position by binarizing the illuminance, the input position can be reliably specified from the position of only a specific cell.

Further, since the illuminance is corrected based on the external environment state and the input position is determined based on the corrected illuminance, the photodiode cell 15 whose characteristics fluctuate depending on the environmental state such as external temperature and external light illuminance is used. Even if the area sensor 2 is configured, the input position can be stably specified regardless of the external environment state.

Since the area sensor 2 using the photodiode cell 15 realized by a-Si is formed in a planar shape, the original is brought into contact with the entire surface of the sensor to read the image drawn on the original. It is possible to input image information, and it is also possible to add such an image reading and inputting function in addition to the above-mentioned inputting function with the operator's finger or input pen.

[0027]

As described above, according to the present invention, when the light incident on each light receiving element cell is shielded by the operator's finger or a predetermined input pen, the specific cell whose incident light is shielded and its Illuminance according to different current values output from other cells can be obtained for each cell, and the input position can be determined based on the illuminance.

According to the present invention, since the input position is determined by binarizing the illuminance, it is possible to reliably specify the input position from the position of only a specific cell where incident light is completely blocked. Can be.

Further, according to the present invention, the illuminance is corrected based on the external environment state, and the input position is determined based on the corrected illuminance. Therefore, the characteristics vary depending on the environmental state such as the external temperature and the external light illuminance. Even if the input means is configured by using the light receiving element cells, the input position can be stably specified regardless of the external environment state.

Further, according to the present invention, the correction of the illuminance based on the external environment state can be specifically performed by selecting a correction condition according to the acquired external environment state.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electrical configuration of an input device 1 according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing an area sensor 2.

FIG. 3 shows an area sensor driver 3 connected to each column line wiring 17;
FIG. 5 is a diagram showing bias voltages VB1 to VB4 supplied from the power supply.

FIG. 4 is a diagram showing a complete light shielding area A2 in a daylighting area A1 of the area sensor 2 for explaining an operation of the characteristic position calculating unit 5;

FIG. 5 is a flowchart for explaining an input position determination operation of the input device 1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Input device 2 Area sensor 3 Area sensor driver 4, 8 A / D converter 5 Feature position calculation part 6 Binarization part 7 Environment sensor 9 Compensation data ROM 10 Compensation value calculation part 11, 12 D / A converter 13 Programmable gain Amplifier 15 Photodiode cell

Claims (4)

[Claims] 1. An input means comprising: a plurality of light receiving element cells arranged in a matrix form; and input means for outputting a current value corresponding to a bias voltage applied to each element and illuminance of incident light for each element; An input device comprising: illuminance acquisition means for obtaining illuminance according to a current value from a light receiving element cell for each cell; and input position determination means for determining an input position based on the obtained illuminance. 2. The input position determining means includes a binarizing means for binarizing each illuminance obtained by the illuminance obtaining means, and calculates a binary value of 0 or 1 from a light receiving element cell position of the binarized illuminance. The input device according to claim 1, wherein the input position is determined. 3. An external environment state acquisition unit that acquires an external environment state of the input device, and a correction unit that corrects the illuminance obtained by the illuminance acquisition unit based on the acquired external environment state, The input device according to claim 1, wherein the input position determining means determines the input position based on the corrected illuminance. 4. The input device includes a storage unit that stores a correction condition predetermined for each external environment state, wherein the correction unit performs correction according to the external environment state acquired by the external environment state acquisition unit. 4. The input device according to claim 3, wherein a condition is selected from the storage unit, and the illuminance is corrected based on the selected correction condition.