JPS61151728A - Coordinate detector - Google Patents

Abstract

PURPOSE:To discriminate accurately an input corresponding to the output even when the output has a variance by providing a coordinate input panel having a substrate having a low resistance film comprised of a low resistance region and a high resistance region inserted via low resistance regions. CONSTITUTION:Since the low resistance region 23A and the high resistance region 23B exist alternately on a coordinate input panel IP, a prescribed change in the input position, e.g., movement of the input position on the X axis has an output change where slow and steep parts are included alternately. Thus, even when any part of an object display items receives an input, outputs O0A-O1A and O0B-O1B of display items A, B whose output variances are adjacent are not overlapped and one display items A or B is discriminated accurately.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention selectively adds impedance to a resistive film formed on a substrate, and determines coordinate values indicated corresponding to the points to which the impedance is added. This invention relates to an improvement of a coordinate detection device for detecting.

[Conventional technology]

In recent years, it has become popular to input graphics or characters into electronic computers for processing.

Keyboards are often used as input means in such cases, but in addition to these, keyboards can also be operated as panel switches while observing the display using a finger or a pen. The range of use of transparent switches and the like is gradually expanding because the surface design can be selected relatively freely.

By the way, the panel switch requires a coordinate detection device to detect the input point. For example, a transparent conductive film is formed on the surface of a transparent film, and upper and lower transparent electrode patterns are arranged at regular intervals. It is known that devices are arranged facing each other in a grid pattern and allow data to be input simply by lightly touching them with a fingertip, without using a keyboard.

Based on the above-mentioned technological trends, the present inventors conceived of a coordinate detection device based on an operating principle different from existing technology, with the aim of increasing the degree of freedom in the design of the coordinate input panel in the coordinate detection device. did.

In other words, when the equivalent impedance seen from one terminal side of the resistive film is clamped by a buffer circuit added to both ends of the resistive film, the coordinate relationship with the indicated point becomes a specific functional relationship. We have provided a device that detects coordinates from values.

FIG. 3 is a block diagram of essential parts of the previously provided coordinate detection device.

In the figure, 1 is a resistive film of uniform material, 2 and 3 are the side edges of the resistive film 1, 4 is a pointing point indicating the appropriate position of the resistive film 1, 5 is a connection point, σ is an operational amplifier, and 7 8 is a ground, 8 is an impedance portion, 9 is a variable capacitance digital oscillator, 1O is a pulse width measuring device, and 11 is an output terminal. Incidentally, the impedance portion 8 is a capacitance component etc. generated between the human body and the ground 7 when a proper point on the resistive film 1 is pointed with a fingertip, and the impedance is assumed to be 20.

Here, it is assumed that the coordinates of the side edge 2 of the resistive film 1 are "0" and the coordinates of the side edge 3 are "1", and the coordinate X of the indicated point 4 takes a value of O:5x≦1, and The ground potential of indicating point 4 is vl
, the potential of the side edges 2 and 3 of the resistive film 1 with respect to the ground 7 is V,
Resistance between side edge 2 of resistive film 1 and indication point 4 is RX% Resistive film 1
The resistance between the side end 3 of Let us consider a case where the equivalent impedance is Z, and the equivalent impedance Z is calculated.

The current vm/Z0 flowing through the mass and impedance Z0 is,
Current (V-V, )/ flowing through the resistance R, via the indicating point 4
Current flowing through RX and resistor RI-X (v-Vm)/R
+-x, (va/zo) = (V-V,)'((1/Rx)+ (1/R1-x
))...(11) Since the side edge 3 of the resistive film 1 is clamped with a buffer circuit (voltage follower β=1.0), the resistance Rl-X
The current flowing through is independently supplied from a buffer circuit.

Therefore, the current flowing through the connection point 5 is the current flowing through the resistor RX itself.

From this, the current v flowing through the equivalent impedance 2
/ Z is equal to the current (v-v,)/RX flowing through the resistor RX, (v/Z) = (v-vll)/RX -... (
2).

When calculating the equivalent impedance from equations (1) and (2), Z=Rx +Zo ((R11+R1-X)
/Rt-x)・・・・・(3) However, the resistance RX + R1-X and the impedance Z are set so that the resistance (RX + R1-X) is sufficiently small compared to the absolute value IZ01 of the impedance Z. , then equation (3) approximately becomes Z#Zo ((R
)I +RI-11) /R1-X)・・・・・
(4) It can be done.

Furthermore, as can be understood from Fig. 3, the resistance value in the resistive film l is proportional to the length, so the coordinates
-RX / (RX + RI-X) From the formula, the resistance R
, -8, we get R+-x-((1-x)/x)Rx...(
5).

Substituting equation (5) into equation (4) to find X, x-1(Z
o /Z) ...16).

As can be seen from equation (6), the coordinates X of indicated point 4 are connected to connection point 5.
The coordinate X is inversely proportional to the equivalent impedance Z between the ground and the ground 7, and the coordinate X can be determined by measuring the values of the equivalent impedance Z and the impedance z0 and calculating the value of X.

[Problem that the invention seeks to solve]

By the way, the coordinate detection device described above has a detection error that depends on the number of processing bits and variations in the resistive film.

FIG. 4 is a diagram showing the relationship between input coordinates and output, with input coordinates plotted on the horizontal axis and output plotted on the vertical axis.

As can be seen from the figure, ±
This results in an output error of δ.

In other words, it is not possible to specify the input for a certain output.

FIG. 5 is a diagram similar to FIG. 4, and as seen in the diagram, when a certain output O appears, it becomes ■. It is only known that there was an input in the range of ~I, and it is not possible to specify which input the output corresponds to.

In general, touch coordinates are often used to input items such as alphanumeric items, and in this case, inputting items with a finite size will cause variations in the input position, so the output will also vary within the range. This will result in

Figure 6 is a diagram similar to Figures 4 and 5, with item A
With the input of , the output is 00 due to the variation in the input position.
It is shown that variations occur in the range of s-01A, and in the input of item B, the output varies in the range of 0° to 01B.

In the case of Fig. 6, if the actual output is within Of1m~OIA, it is unclear whether it is the input of item A or item B. To avoid this, each input Items must be set at least as far apart as the item size.

According to the present invention, even if there are variations in the outputs of an analog touch coordinate input panel having a resistive film, the outputs do not overlap each other and can be associated with the input items on a 1:1 basis.

[Means for solving problems]

To explain with reference to FIGS. 1 and 2, which are diagrams for explaining one embodiment of the present invention, the coordinate detection device of the present invention includes a low resistance area 23A corresponding to the display item 21 and the low resistance area It has a structure including a coordinate input panel IP having a glass substrate 22 on which a resistive film 23 consisting of a high resistance region 23B interposed between 23A and 23A is formed.

[Effect]

With the above structure, the low resistance area 23A is divided by the high resistance area 23B, so inputting by touching the low resistance area 23A is equivalent to inputting with a keyboard. Even if there are variations in the outputs corresponding to the respective input items on the coordinate input panel, there will be no overlap in the outputs, and accurate input determination can be made.

〔Example〕

FIGS. 1A and 1B show a cut-away slope view and a cut-away side view of the main parts for explaining one embodiment of the present invention.

In the figure, 21 is, for example, a CRT (cath).

22 is a glass substrate, 23 is a resistive film consisting of a low resistance region 23A and a high resistance region 23B, IP
indicate touch coordinate input panels, respectively.

In this embodiment, the sheet resistance of the low resistance region 23A shown as a white rectangular part is of course lower than that of the high resistance region 23B shown as a hatched part. Moreover, they correspond to the display items 21, respectively.

FIG. 2 is a diagram showing the relationship between input coordinates and output of the embodiment shown in FIGS. 1(a) and (b), and FIGS.
Similar to the figures, the horizontal axis shows input coordinates, and the vertical axis shows output, and the same parts as those explained in relation to those figures are indicated by the same symbols.

In the coordinate input panel IP shown in FIG. 1, the low resistance area 23A and the high resistance area 23B exist alternately.
As seen in the figure, a constant change in input position, e.g.
With respect to the movement of the input position on the axis, the output change alternately includes slow parts and steep parts.

As you can see, no matter where the input is in the target display item, the output variation will be accurate because the outputs 0°1~OIA and 0°■~0□ of adjacent display items A and B do not overlap. One display item A or B can be determined.

Here, the case of manufacturing the coordinate input panel explained with reference to FIG. 1 will be explained.

First, a vapor deposition or sputtering mask having the same pattern as the high resistance region 23B is prepared.

The resistive film 23 made of ITO (indium oxide + tin oxide) is formed by placing the mask on the glass substrate 22 at an appropriate distance and applying a vapor deposition method or a sputtering method.

As described above, when the mask is separated from the glass substrate 22 by an appropriate distance, the material is deposited thickly on the unmasked portions to form the low resistance region 23A, and the material wraps around the masked portions. A high resistance region 23B is formed by thinly depositing the film. Note that the thickly deposited low resistance region 23A and the thinly deposited high resistance region 23A
Of course, it is electrically and mechanically continuous with B.

〔Effect of the invention〕

The coordinate detection device of the present invention includes a coordinate type cover panel having a substrate on which a resistive film is formed, consisting of low resistance areas corresponding to display items and high resistance areas interposed between the low resistance areas. .

According to such a configuration, low resistance areas and high resistance areas in the resistance film exist alternately, and the low resistance area is divided by the high resistance area, so that the display device Manually touching the low resistance area corresponding to the display item above is equivalent to inputting data using a keyboard, and there are variations in the output corresponding to each input item in the coordinate system Cabanel. Even if the output is different, there is no overlap in the output, and the human power corresponding to the output can be accurately determined.

[Brief explanation of drawings]

Figure 1 (al and (bl) are a cut-away slope view and a cut-away side view of essential parts of one embodiment of the present invention, and Figure 2 is a diagram showing the relationship between coordinate input and output for the embodiment shown in Figure 1. , Figure 3 is a block diagram of the main parts of a conventional coordinate detection device, and Figures 4 to 6 are diagrams showing the relationship between coordinate human power and output to explain the shortcomings of the conventional technology. In the figure, 21 is a display item, 22 is a glass substrate, and 23 is a display item.
is a resistive film, 23A is a low resistance region, 23B is a high resistance region,
IP indicates a coordinate type Cabanel. Patent Applicant Fujitsu Ltd. Representative Patent Attorney Akira Aitani Representative Patent Attorney Hiroshi Watanabe - Figure 1 Figure 2 Item B Item A Figure 3 1 Manual coordinate input Figure 5 In Is Input coordinate 6 figure

Claims (1)

[Claims] A coordinate detection device comprising: a coordinate input panel having a substrate having a resistive film formed of low resistance regions corresponding to display items and high resistance regions interposed between the low resistance regions.