JPH0350291B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the position indicated by a writing instrument such as a pen, or the character/character written with a writing instrument on a flat input surface.
The present invention relates to a tablet input device for recognizing or displaying figures, etc.

[Summary of the invention]

The present invention provides a tablet input device that is compatible with pointing devices such as a mouse by including a coordinate conversion processor and calculating coordinates.

[Conventional technology]

A conventional example is shown in FIG. Here, an absolute coordinate output type tablet input device was proposed, and JP-A-59-
It is disclosed in Publication No. 165182. This means that the coordinates of doublet 1 are converted to orthogonal coordinate values x by coordinate detector 2.
This is a tablet input device that detects and y, temporarily stores them in an output buffer 4, and outputs them.

[Problem and purpose to be solved by the invention]

However, since the above-mentioned conventional technology outputs absolute coordinates, it is not compatible with other pointing devices that output relative coordinates, such as mice and trackballs, and requires dedicated input processing. There was a problem that it could not be used as a substitute for etc.

Therefore, an object of the present invention is to provide compatibility with a mouse and the like.

[Means to solve the problem]

The tablet input device of the present invention detects an input to an input surface and digitally outputs an X coordinate value and a Y coordinate value corresponding to the input, and includes a first X register that stores the latest X coordinate value. , a second X register that stores the most recent X coordinate value, a first Y register that stores the latest Y coordinate value, a second Y register that stores the most recent Y coordinate value, and the first The latest X stored in the X register of
a first switch that switches and outputs the coordinate value and the latest Y coordinate value stored in the first Y register at the constant time interval; and the immediately previous X coordinate value stored in the second X register. and a second switch that switches and outputs the immediately previous Y coordinate value stored in the second Y register at the constant time interval;
A relative coordinate output mode in which the immediately previous coordinate value output from the second switch is subtracted from the latest coordinate value output from the first switch, and the latest coordinate value output from the first switch is output. a subtracter having an absolute coordinate output mode for passing and outputting coordinate values; a control register for inputting a control signal for selecting either the relative coordinate output mode or the absolute coordinate output mode to the subtracter; and the subtractor. The apparatus is characterized by comprising an output register that temporarily stores the output from the device and alternately outputs the X coordinate value and the Y coordinate value at each predetermined time interval.

[Effect]

According to the above configuration of the present invention, not only absolute coordinates but also relative coordinates can be outputted as output data, and compatibility with a mouse or the like can be achieved.

〔Example〕

FIG. 1 shows an overall configuration diagram of the present invention. 1 is a tablet on which characters and figures are actually written using a writing instrument such as a pen. 2 is a coordinate detector and is 10m
Coordinate values are sampled at fixed time intervals such as seconds. The coordinate values calculated by the coordinate detector 2 are converted from absolute coordinates to relative coordinates by a coordinate conversion processor 3.
That is, if the coordinate values obtained from the coordinate detector 2 are (xi, yi) in the orthogonal coordinate system, then Xi=xi−xi _-1 ...(1) Yi=yi−yi _-1 ...(2) By doing this, the relative coordinates (Xi, Yi) in the orthogonal coordinate system can be obtained. FIG. 3 is a detailed circuit diagram that can perform the processing described above. Reference numeral 1 denotes a tablet, which in this case has a uniform resistive film on its surface, and is placed with the resistive films facing each other at a constant distance. A constant current is supplied to the tablet 1 from a constant current source 5. However, this only applies when the upper and lower plates of the tablet come into contact with each other due to writing, and if they are not in contact, no current will flow. As a result, a voltage is generated across the resistor 8 only when writing is performed with the writing instrument, and by detecting this voltage with the voltage comparator 11, a signal indicating whether writing is being performed with the writing instrument is obtained. It will be done. Hereinafter, a signal indicating a state in which writing is being performed on the tablet with a writing instrument will be referred to as a pen-on signal, and a signal indicating a state in which writing is not being performed because the writing instrument is away from the tablet will be referred to as a pen-off signal.

A voltage proportional to the x-coordinate of the orthogonal coordinate system appears across the resistor 6, and the differential amplifier 9
The voltage is amplified so that it swings within a certain range, such as 5V. Similarly, a voltage proportional to the y-coordinate of the orthogonal coordinate system appears across the resistor 7, and the differential amplifier 10
The voltage is amplified so that it swings within a certain range. The outputs of differential amplifiers 9 and 10 are alternately sent to A/D converter 13 by switch 12 . The A/D converter 13 converts the voltage into a digital value at fixed time intervals such as 5 msec. The digital values are distributed to the X register 14 for the x coordinate and to the Y register 15 for the y coordinate in synchronization with the switch 12, and are temporarily stored.

XB register 16 (second X register) contains one sample time (10
m seconds) previous value is stored. Similarly, the YB register (second Y register) stores the value one sample time ago, which is the data immediately before the latest Y coordinate. The switch 18 (first switching unit) is the latest
X register 14 (first X
register) and the Y register 15 (first Y register) in which the latest Y coordinate value is stored are switched at fixed time intervals of 5 msec, which is half of one sample time. Similarly, the switch 19 (second switch) switches the XB register 16, which stores the X coordinate value one sample time ago, which is the previous data, and the YB register 17, which stores the Y coordinate value one sample time ago, for 5 ms. Switch at regular intervals. The subtracter 20 is the switch 18
The output value of the switch 19 is subtracted from the output value of. That is, in the output of the subtracter 20, Xi in equation (1) and Yi in equation (2) appear alternately at fixed time intervals (such as 5 msec).
The output register 21 stores the output from the subtracter 20 for one hour, and outputs the X coordinate value and the Y coordinate value alternately at fixed time intervals of 5 msec.

The operation of the subtracter 20 is controlled by a 1-bit signal (control signal) in an input register (control register) 22. That is, a 1-bit control signal can be used to select and switch between outputting the output of the switch 18 as it is (absolute coordinate output mode) and performing the above-described subtraction process (relative coordinate output mode).

On the other hand, the XB register 16 and YB register 17 are reset when the pen-off signal changes to the pen-on signal. The reset method at this time is 2.
This selection is also made by the value of the other 1 bit in the input register 22. The first reset procedure sets the value of the XB register 16 to the same value as the X register 14 after the pen-on signal is output, and sets the value of the YB register 17 to the same value of the Y register 1 after the pen-on signal is output.
This method resets it to the same value as 5. According to this method, relative coordinates are output only when the writing instrument is continuously writing (the pen-on signal continues). Therefore, even if the writing instrument leaves the tablet 1 midway, no change in its coordinate value will be output. In other words, it can be used in exactly the same way as a mouse. Second
The reset method is to set the value of the XB register 16 to the same value as the X register 14 before the pen-off signal was issued,
This method resets the value of the YB register 17 to the same value as the Y register 15 before the pen-off signal was issued. According to this method, the output data is similar to that of a mouse, but it also outputs the direction in which the writing instrument moves away from the tablet, so it is possible to preserve the positional relationship of characters and figures written on the tablet and transmit the data. It becomes possible.

〔Effect of the invention〕

As described above, according to the present invention, by providing a control register that controls whether the subtracter performs a subtracting operation or a passing operation, relative coordinates are output by subtracting the previous coordinate value from the latest coordinate value. It is possible to switch between the absolute coordinate output mode, which passes through and outputs the latest coordinate values in the output mode, so it is a tablet input that combines the mouse-like input function in the relative coordinate output mode and the handwritten input function in the absolute coordinate output mode. You can get the equipment.

In addition, there is a first switch that switches and outputs the latest X coordinate value and the latest Y coordinate value at fixed time intervals, and a first switch that switches and outputs the previous X coordinate value and the previous Y coordinate value at fixed time intervals. The second switch switches the X coordinate value and the Y coordinate value at regular intervals, subtracts or passes through the subtracter, and outputs via the output register, so both the subtracter and the output register There is no need to provide it for each Y coordinate. Therefore, the circuit configuration can be greatly simplified. Furthermore, since the X and Y coordinates are alternately output to the outside using one output register, there is no need to provide dedicated communication lines for each of the X and Y coordinates.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the tablet input device of the present invention. FIG. 2 is a block diagram of a conventional example. FIG. 3 is a circuit diagram of an embodiment of the present invention. 1...Tablet, 2...Coordinate detector, 3...
Coordinate conversion processor, 4...Output buffer, 5...Constant current source, 6, 7, 8...Resistor, 9, 10...Differential amplifier, 11...Voltage comparator, 12...Switcher, 13...A/D converter, 14...X register, 15...Y register, 16...XB register, 17...YB register, 18, 19...switcher, 20...subtractor, 21... Output register, 22...Input register.

Claims (1)

[Scope of Claims] 1. In a tablet input device that detects an input to an input surface and digitally outputs an X coordinate value and a Y coordinate value corresponding to the input, the tablet input device includes: a first X register that stores the latest X coordinate value; A second X register that stores the most recent X coordinate value; A first Y register that stores the most recent Y coordinate value; A second Y register that stores the most recent Y coordinate value; a first switch that switches and outputs the latest X coordinate value stored in the X register and the latest Y coordinate value stored in the first Y register at the constant time interval; a second switch that switches and outputs the immediately preceding X-coordinate value stored in the register and the immediately preceding Y-coordinate value stored in the second Y register at the constant time interval; and from the first switching device. A relative coordinate output mode in which the immediately previous coordinate value output from the second switch is subtracted from the latest coordinate value to be output, and the latest coordinate value from the first switch is passed through and output. a subtracter having an absolute coordinate output mode, a control register that inputs a control signal for selecting either the relative coordinate output mode or the absolute coordinate output mode to the subtracter, and an output from the subtracter; A tablet input device characterized by comprising an output register that temporarily stores the X coordinate value and the Y coordinate value and outputs the X coordinate value and the Y coordinate value alternately at each predetermined time interval.