JP2645566B2 - Coordinate detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Overview] Regarding a coordinate detecting device for detecting a contact position of a coordinate detecting panel, a conversion from a measured coordinate to a contact coordinate is performed at high speed, and a coordinate of an actual contact position on the coordinate detecting panel is calculated. A coordinate detection panel, and a signal supplied from the coordinate detection panel are measured to calculate measurement coordinates, and the calculated measurement coordinates are converted to convert the calculated measurement coordinates. A contact coordinate detecting device for detecting contact coordinates in the coordinate detecting device, wherein the contact coordinate detecting device includes a coordinate conversion table indicating a correspondence relationship between the measured coordinates and the contact coordinates,
The measurement coordinates are converted into corresponding contact coordinates according to the coordinate conversion table, and the coordinates of the actual contact position on the coordinate detection panel are detected.

[Industrial applications]

The present invention relates to a coordinate detection device, and more particularly, to a coordinate detection device that detects a contact position of a coordinate detection panel.

[Conventional technology]

In recent years, with the development of office automation, etc.,
For example, input of characters and predetermined instructions to a computer or the like is actively performed. A keyboard is generally used for inputting such characters. For example, a character or the like is arranged by placing it on a display and touching a position corresponding to an image displayed on the display with a finger or a pointing stick. Attention has been paid to an image detection device capable of performing the input of the image.

Conventionally, a coordinate detection device includes a coordinate detection panel and a contact coordinate detection circuit that detects a contact coordinate of the coordinate detection panel based on a signal supplied from the coordinate detection panel.
Recently, simplified electrode structure (for example, to four electrodes)
As a result, research and development have been made on a coordinate detecting device for the purpose of reducing the manufacturing cost and improving the reliability.

[Problems to be solved by the invention]

As described above, a coordinate detection device that has been recently researched and developed includes, for example, four coordinate detection devices provided at four corners of a coordinate detection panel.
The coordinates of the contact position on the coordinate detection panel are detected by the two electrodes. In such a coordinate detection device, since a current cannot flow in parallel to the coordinate detection panel (resistive film), first, a signal supplied from the coordinate detection panel is measured to calculate measurement coordinates. After that, the calculated measurement coordinates are converted according to a predetermined function, and the coordinates of the actual contact position (contact coordinates) on the coordinate detection panel are detected.

By the way, conventionally, the conversion from the calculated measurement coordinates to the contact coordinates is performed by a calculation process using a predetermined conversion function. The arithmetic processing for converting the measured coordinates into the contact coordinates requires a certain amount of time, and thus it is difficult to detect the coordinates of the actual contact position on the coordinate detection panel in a very short time. Therefore, it has been difficult to configure a high-speed input device using the coordinate detection device as described above.

The present invention has been made in consideration of the above-described problems of the conventional coordinate detection device, and performs high-speed conversion from measurement coordinates to contact coordinates to detect coordinates of an actual contact position on a coordinate detection panel in an extremely short time. With the goal.

[Means for solving the problem]

FIG. 1 is a block diagram showing the principle of a coordinate detecting device according to the present invention.

According to the present invention, a coordinate detection panel 1a, a measurement coordinate is calculated by measuring a signal supplied from the coordinate detection panel 1a, and the calculated measurement coordinate is converted to obtain a contact coordinate on the coordinate detection panel. A contact coordinate detecting device for detecting the contact coordinate, wherein the contact coordinate detecting device includes a coordinate conversion table 30 indicating a correspondence between the measured coordinates and the contact coordinates; 30 is
The coordinate detection panel is divided into four equivalent areas, and a division coordinate conversion table indicating a correspondence relationship between measurement coordinates and contact coordinates common to the respective equivalent areas is provided. It is determined which equivalent region belongs to, and the measured coordinates are converted into the corresponding divided contact coordinates in the corresponding equivalent region according to the divided coordinate conversion table, and the divided contact is converted by the equivalent region to which the contact position belongs. A coordinate detecting device is provided, wherein the coordinates are corrected to detect the coordinates of the actual contact position on the coordinate detecting panel 1a.

(Operation)

According to the coordinate detecting device of the present invention having the above-described configuration, the contact coordinate detecting means 3 includes the coordinate conversion table 30 indicating the correspondence between the measured coordinates and the contact coordinates. The measured coordinates calculated by measuring the supplied signal are rapidly converted to the coordinates of the actual contact position on the coordinate detection panel 1a. That is, the coordinate conversion table 30 is configured as a divided coordinate conversion table that divides the coordinate detection panel into four equivalent areas and indicates the correspondence between the measurement coordinates and the contact coordinates common to each equivalent area. It is determined to which of the divided equivalent areas the touch position of the panel belongs, and further, the measured coordinates are converted into the divided contact coordinates in the corresponding equivalent area according to the divided coordinate conversion table, and the equivalent area to which the contact position belongs is determined. The coordinates of the actual contact position on the coordinate detection panel 1a are detected by correcting the converted divided contact coordinates. Thus, the coordinates of the actual contact position on the coordinate detection panel can be detected in a very short time. Further, by dividing the coordinate detection panel into four equivalent areas, it is possible to reduce the capacity of the storage device used as the coordinate conversion table and to reduce the cost.
The processing speed can be improved because the search capacity for coordinate conversion is also reduced.

〔Example〕

Hereinafter, an embodiment of a coordinate detecting device according to the present invention will be described with reference to the drawings.

FIG. 2 is a view showing one embodiment of the coordinate detecting device of the present invention. As shown in the figure, the coordinate detecting device of the present embodiment includes a coordinate detecting panel 1a and a contact coordinate detecting circuit 3. The coordinate detection panel 1a includes a substrate 1 made of a transparent material such as glass or acrylic, and an ITO (In ₂₎ formed on the substrate 1.
It comprises a transparent resistive film 2 such as O ₃ : Sn) and four electrodes 21, 22, 23, 24 provided at four corners of the resistive film 2, respectively.

The four electrodes 21 to 24 are connected to the switches SW _{1 to} SW ₄ of the switching circuit 31, respectively.
By 31, two sets of electrode groups arranged in parallel from the four electrodes are selected. The selected two electrode groups are connected to the input terminal I ₀ and the output terminal O ₀ of the buffer circuit 32.
It is connected to the connected one electrode group to the input terminal I ₀ of the buffer circuit 32 is connected to the impedance measuring circuit 33, so that the impedance of the contact position from the one electrode group said is measured. Here, the selected two electrode groups are combinations of the left side electrode groups 21 and 22 and the right side electrode groups 24 and 23 and the upper side electrode groups 21 and 24 and the lower side electrode groups 22 and 23. The selected two electrode groups are switched by the switching circuit 31 to the input terminal I ₀ and the output terminal of the buffer circuit 32.
The connection is inverted to O ₀ , and the impedance of the contact position from the other electrode group is also measured by the impedance measurement circuit 33.

The output signal of the impedance measurement circuit 33 is supplied to the control processing circuit 34, and the measurement coordinates (X, Y) are calculated from the measured impedance. The control processing circuit 34 is also configured to supply a selection signal of two sets of electrodes to be measured to the switching circuit 31. Then, the calculated measurement coordinates (X, Y) are calculated according to the coordinate conversion table 30.
This is converted into the contact coordinates (x, y) of the contact position P of the resistive film 2. This coordinate conversion table 30, for example,
The data is stored in a ROM, and a predetermined conversion is performed from the data stored in the ROM chip.

In the above, the contact coordinates (x, y) from the measurement coordinates (X, Y)
This conversion process is required because the four electrodes 21 to 24 in this embodiment are provided at the four corners of the resistance film 2.
That is, the left side electrode groups 21 and 22, the right side electrode groups 24 and 23 selected from the four electrodes 21 to 24, and the upper side electrode group 2
The current flowing between the lower electrode group 22 and the lower electrode group 22 does not flow through the resistive film 2 in parallel, so that the measurement coordinates (X,
Y) and the actual contact coordinates (x, y) are different, and the measurement coordinates (X,
A conversion process is required to derive the actual contact coordinates (x, y) from Y).

Here, the procedure of detecting the contact coordinates in the coordinate detecting device of FIG. 2 will be described. First, switch _{1 of} switching circuit 31 is connected to I
₁ side, SW ₂ to I ₂ side, SW ₃ to O ₃ side and SW ₄ to O ₄ side,
That is, the left side electrode group 2 to the input terminal I ₀ of the buffer circuit 32
Connect the 1 and 22, by connecting the right side electrodes 24 and 23 to the output terminal O ₀ of the buffer circuit 32, the measurement volume from the left side electrodes 21 and 22 (impedance) C _L in the impedance measuring circuit 33 I do. Next, SW _{1 of the} switching circuit 31 is set to the O ₁ side, and SW _{2 is set} to the O ₂ side.
Side, connecting SW ₃ to the I ₃ side and SW ₄ to the I ₄ side,
Connect the right side electrodes 24 and 23 to the input terminal I ₀ of the buffer circuit 32, by connecting the left-side electrodes 21 and 22 to the output terminal O ₀ of the buffer circuit 32, from the right side electrodes 24 and 23 measuring the capacitance C _R in the impedance measuring circuit 33.

Similarly, SW ₁ of the switching circuit 31 is on the I ₁ side, SW ₂ is on the O ₂ side,
SW ₃ is connected to the O ₃ side and SW ₄ is connected to the I ₄ side, that is, the upper side electrode groups 21 and 24 are connected to the input terminal I ₀ of the buffer circuit 32,
Connect the lower side electrodes 22 and 23 to the output terminal O ₀ of the buffer circuit 32 measures the capacitance C _U from the upper side electrodes 21 and 24 in the impedance measuring circuit 33. Next, the switching circuit 31
SW _{1 is connected} to the O ₁ side, SW _{2 is connected} to the I ₂ side, SW ₃ is connected to the I ₃ side, and SW ₄ is connected to the O ₄ side, that is, the lower side electrode group 22 is connected to the input terminal I ₀ of the buffer circuit 32. connect 23, by connecting the upper side electrode group 21 and 24 to the output terminal O ₀ of the buffer circuit 32 measures the capacitance C _D from the lower side electrodes 22 and 23 in the impedance measuring circuit 33.

As described above, the measurement coordinates (X, Y) are calculated as shown in the following equation.

The measurement coordinates (X, Y) thus obtained are converted in the coordinate conversion table 30. In the coordinate conversion table 30, data in which the measurement coordinates (X, Y) and the contact coordinates (x, y) are associated with each other by the following function formula is written.

_{x = f x (X, Y} , l x, l y) y = f y (X, Y, l x, l y) Next, the above measurement coordinates (X, Y) from the contact coordinate (x, y) A function expression for obtaining the following will be described.

FIG. 3 is a diagram for explaining detection of contact coordinates in the coordinate detecting device of FIG. As described above, the coordinate detection device according to the present embodiment includes the left side electrode groups 21, 22 and the right side electrode groups 24, 23 and the upper side electrode groups 21, 24, which are selected from the four electrodes 21 to 24, and the lower side electrode group. Since the current flowing between the electrode groups 22 and 23 does not flow in parallel through the resistive film 2, a conversion process from the measured coordinates (X, Y) to the actual contact coordinates (x, y) is required. It is said.

As shown in FIG. 3, when the electrodes 21, 22, 23, and 24 are formed at the four corners of the rectangular resistive film 2, the distance between the electrodes in the horizontal direction (between the electrodes 21 and 24 and between the electrodes 22 and 24) is reduced. Between electrodes 23)
The distance and l _x, also, between the longitudinal direction of the electrode (the electrode 21 and the electrode
The distance 22 between and between electrode 24 and electrode 23) as l _y, further the contact position P (x resistive film 2, y) from each electrode 21,22,2
Each l ₁ the distance to the 3,24, l _2, l _3, When l _4, the resistance value R _L from the left side to the contact position P, the resistance from the right side to the contact position P R _R, the contact position from the upper side resistance R _D of the resistance value R _U and the lower side to the P to the contact position P, respectively represented by the following formula.

Here, the resistance value per unit length of the resistance film 2 is represented by r.

The distances l ₁ , l ₂ , l ₃ , l ₄ from the contact position P (x, y) to the respective electrodes 21 to 24 are represented by the following equations, respectively.

^{_{l 1 = (x 2 + y}} 2) 1/2 l 2 = _{^{[x 2 + (l y -y)}} 2 ] ^1/2 l ₃ = ^{_{[(l x -x) 2 + y}} 2 ] ^1/2 l ₄ = ^{_{[(l x -x) 2 + (}} l y -y) 2 ] is ^1/2.

 Therefore, the measurement coordinates (X, Y) are represented by the following equation.

By summarizing the above equations, the contact coordinates (x, y)
Can be expressed as follows:

_{x = f x (X, Y} , l x, l y) y = f y (X, Y, l x, l y) Figure 4 is a diagram showing the coordinate conversion table in the coordinate detection apparatus of FIG. 2 . As described above, the contact coordinates (x,
y) is associated with the measurement coordinates (X, Y) by a predetermined function, so that the measurement coordinates (X, Y) correspond to the contact coordinates (x, y).
Is the coordinate conversion table
30 will be written. For example, the control processing circuit 34
When the measurement coordinates (X ₁ , Y ₃ ) are calculated in, the contact coordinates (x ₁ , y ₃ ) of the actual contact position on the resistive film 2 are output according to the coordinate conversion table 30. For example, since the coordinate conversion table 30 is supplied as a ROM, the conversion from the measurement coordinates (X ₁ , Y ₃ ) to the contact coordinates (x ₁ , y ₃ ) is performed in a very short time. .

FIG. 5 is a diagram for explaining a case where measured coordinates are converted into contact coordinates using a coordinate conversion table in the coordinate detection device of the present invention. As shown in FIG.
For example, when the position of the coordinate P (30, 20) on the coordinate detection panel 1a is touched, the signal from the coordinate detection panel 1a is
It is supplied to a control processing circuit 34 via a switching circuit 31, a buffer circuit 32 and an impedance measuring circuit 33.
Then, in the control processing circuit 34, the measurement coordinates Q (40, 30) are calculated as shown in FIG. As described above, the measurement coordinates Q (40, 30) are calculated as different from the coordinates P (30, 20) of the coordinate detection panel 1a actually touched due to, for example, the configuration of the electrodes. I have. The measured coordinates Q (40, 30) are converted by the coordinate conversion table 30 shown in FIG. 3C, and the coordinates p (3) coincide with the actual contact coordinates as shown in FIG.
0,20) is taken out as the output of the coordinate detecting device.

FIG. 6 is a view for explaining a modified example in which the coordinate detection panel is divided into four and coordinate conversion is performed in the coordinate detection device of the present invention. As shown in the figure, in this modification, the coordinate detection panel 1a is divided in the x and y directions from the center to form four equivalent areas S ₀ , S ₁ , S ₂ , and S _3. . here,
In the first region S ₁ , the second region S _2, and the third region S ₃ , the positions symmetrical with respect to the contact position P _A0 of the reference region S ₀ are:
The positions P _A1 , P _A2 and P _A3 are respectively, and the positions symmetrical with respect to the contact position P _B0 of the reference area S ₀ are P _B1 , P _B2 and P _B3 , respectively. Thus, any contact position in the reference area S _0, the first respectively second and third regions S _1, S
_2, S can correspond to the symmetrical positions in the _3, thereby dividing relates reference area S ₀ the coordinate conversion table (30
a) can be applied to the first, second and third regions S ₁ , S ₂ , S ₃ respectively. At this time, in the first, second and third areas S ₁ , S ₂ , S ₃ , the measured coordinates in each area are converted into contact coordinates according to the coordinate conversion table of the reference area S ₀ , as described later. That is, a predetermined correction process is performed. As a result, the capacity of a storage device (for example, a ROM) used as a coordinate conversion table can be reduced and the cost can be reduced, and the processing speed can be improved because the search capacity for coordinate conversion is also reduced. it can.

FIG. 7 is a diagram for explaining a case where measured coordinates are converted into contact coordinates using a divided coordinate conversion table in the coordinate detecting device of the present invention. As shown in FIG. 11A, for example, when the user touches the position of the coordinate P ₁ (30, 20) in the second quadrant (reference area) S _{0 on} the coordinate detection panel 1a,
As described with reference to FIG. 5, the coordinate detection panel
The signal from 1a is a switching circuit 31, a buffer circuit 32
And control processing circuit via impedance measuring circuit 33
The measurement coordinate Q ₁ (40, 30) is calculated in the control processing circuit 34 as shown in FIG. The measurement coordinates Q ₁ (40, 30) are converted by the divided coordinate conversion table 30a as shown in FIG. 3C, and coincide with the actual contact coordinates as shown in FIG. The coordinates p (30,20) are calculated. Here, the capacity of the divided coordinate conversion table 30a is 0 <X ≦ 50 and 0 <Y ≦ 50 for the measured coordinates (X, Y), and is 1/4 of the coordinate conversion table 30 in FIG. Is the capacity.

Next, for example, when detecting the position of the coordinate P ₂ (70, 80) in the fourth quadrant (second area) S ₂ in the coordinate detection panel 1a, as described above, the signal from the coordinate detection panel 1a is used. Is supplied to a control processing circuit 34 via a switching circuit 31, a buffer circuit 32, and an impedance measurement circuit 33,
In the control processing circuit 34, the measurement coordinates Q ₂ (60, 70) are calculated as shown in FIG. Furthermore, the calculated measurement coordinate Q ₂ (60, 70), in the control processing circuit 34, the coordinate transformation for applying division coordinate conversion table 30a of the reference area S ₀ for the coordinates of the second region S ₂ That is, the coordinate transformation of (100−60 = 40,100−70 = 30) is performed, and the measured coordinates (40, 30) are shown in FIG.
Is applied to the divided coordinate conversion table 30a shown in FIG. As a result, the measurement coordinates (40, 30) are converted to the contact coordinates (30, 20), and the converted coordinates (30, ₂₎ for the reference area S0 are converted.
0) is returned to the coordinates of the second region S ₂ of the original, i.e.,
Coordinates (30, 20) is (100-30 = 70,100-20 = 80) back to the coordinates of the second region S ₂ of the original by, thereby, coordinates indicating the actual contact position of the coordinate detection panel 1a p ₂ (70,80)
Is obtained, and the coordinates p ₂ (70, 80) are taken out as the output of the coordinate detecting device.

The above description, the case where the contact position P is present in the second region S _2, i.e., the values of X and Y in the measurement coordinate Q is 50 <X ≦ 100, and, in the case where a 50 <Y ≦ 100 is there. Here, the values of X and Y at the measurement coordinates Q are 0 <X ≦ 5.
When 0 and 50 <Y ≦ 100, and when 50 <X ≦ 100 and 0 <Y ≦ 50, the contact position P of the coordinate detection panel 1a is in the first quadrant (first region). Within S ₁ and in the third quadrant (third
It will be present in the area) in S _3. Therefore, the value of X and Y in the measurement coordinate Q, it is possible to determine the contact position P is present in four regions S ₀ to S ₃ throat region. Then, when the contact position P is present in the first region S ₁ or the third area S _3, 50 <X, only for one of the coordinates of the Y ≦ 100 become X or Y, the second region as described above as with the contact position P is present in the S _2, (100-X =
X ′) or (100−Y = Y ′) to obtain 0 <X ′,
The coordinate conversion of the divided coordinate conversion table 30a is performed according to Y '≦ 50. Furthermore, 0 <X, the X or the other of Y coordinates of the Y ≦ 50, as in the case where the contact position P is present in the reference area S in _0, performs coordinate transformation by dividing the coordinate conversion table 30a.
Thus, where in be present (four regions S ₀ to S ₃ may be present in the throat in the region) is applied to coordinate transformation division coordinate conversion table 30a of the contact position P is the coordinate detection panel 1a It can be carried out.

〔The invention's effect〕

As described in detail above, the coordinate detection device according to the present invention performs the conversion from the measurement coordinates to the contact coordinates in accordance with the coordinate conversion table, so that the conversion from the measurement coordinates to the contact coordinates is performed at a high speed. The coordinates of the actual contact position on the coordinate detection panel can be detected in a very short time.

Further, according to the coordinate detection device of the present invention, by dividing the coordinate detection panel into four equivalent areas, it is possible to reduce the capacity of the storage device used as the coordinate conversion table and to reduce the cost. Also, since the search capacity for coordinate conversion is reduced, the processing speed can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the principle of a coordinate detecting device according to the present invention, FIG. 2 is a diagram showing an embodiment of the coordinate detecting device of the present invention, and FIG. 3 is contact coordinates in the coordinate detecting device of FIG. FIG. 4 is a diagram showing a coordinate conversion table in the coordinate detection device of FIG. 2, and FIG. 5 is a diagram showing the contact of measured coordinates using the coordinate conversion table in the coordinate detection device of the present invention. FIG. 6 is a view for explaining a case of converting to coordinates, FIG. 6 is a view for explaining a modification in which a coordinate detection panel is divided into four in the coordinate detection device of the present invention and coordinate conversion is performed, and FIG. It is a figure for explaining a case where measurement coordinates are converted into contact coordinates using a division coordinate conversion table in a coordinate detecting device of the present invention. (Explanation of reference numerals) 1... Substrate, 1a... Coordinate detecting panel, 2... Resistive film, 3... Contact coordinate detecting means, 21, 22, 23, 24. ... Switching circuit, 32 ... Buffer circuit, 33 ... Impedance measurement circuit, 34 ... Control processing circuit, P ... Contact position, S ₀ ... Reference area (second quadrant), S ₁ ... First Area (first quadrant), S ₂ ... Second area (fourth quadrant), S ₃ ... Third area (third quadrant), (X, Y)... Measurement coordinates, (x, y) ...... Contact coordinates.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Minoru Ohashi 1015 Uedanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Kenji 1015 Uedanaka, Nakahara-ku, Nakazaki-ku Kawasaki City, Kanagawa Prefecture Fujitsu Limited ( 56) References JP-A-62-120230 (JP, A)

Claims (2)

(57) [Claims] 1. A coordinate detection panel (1a), measuring signals supplied from the coordinate detection panel to calculate measurement coordinates, converting the calculated measurement coordinates to calculate contact coordinates on the coordinate detection panel. A contact coordinate detecting device (3) for detecting, wherein the contact coordinate detecting device includes a coordinate conversion table (30) indicating a correspondence between the measured coordinates and the contact coordinates;
The coordinate conversion table includes a divided coordinate conversion table that divides the coordinate detection panel into four equivalent areas and indicates a correspondence between measurement coordinates and contact coordinates common to the equivalent areas. Determine which equivalent area the contact position belongs to, and convert the measured coordinates into the corresponding divided contact coordinates in the corresponding equivalent area according to the divided coordinate conversion table, and determine the equivalent area to which the contact position belongs. A coordinate detection device, wherein the converted divided contact coordinates are corrected to detect the coordinates of an actual contact position on the coordinate detection panel. 2. A resistive film formed on a substrate, four electrodes provided at four corners of the resistive film, and a contact connected to the four electrodes for detecting coordinates of a contact position of the resistive film. A coordinate detection device comprising: a coordinate detection unit, wherein the contact coordinate detection unit is connected to one of the two electrode groups, and a switching circuit selects two sets of electrodes in parallel from the four electrodes. And an impedance measuring circuit for measuring impedance corresponding to the contact position of the resistive film, calculating a measurement coordinate from the measured impedance, and performing a predetermined control process; and A coordinate conversion table indicating a correspondence relationship between coordinates of the contact position of the resistive film and a coordinate of the resistive film. The coordinate conversion table divides the resistive film into four equivalent regions and is common to each equivalent region. A coordinate conversion table indicating a correspondence relationship between the measured coordinates and the coordinates of the contact position, determining which of the divided equivalent areas the contact position of the resistive film belongs to, and converting the measured coordinates to the divided coordinates. According to the conversion table, the divided contact coordinates in the corresponding equivalent area are converted, and the converted divided contact coordinates are corrected by the equivalent area to which the contact position belongs, and the coordinates of the actual contact position of the resistive film are detected. A coordinate detecting device, characterized in that: