JP2502648B2 - Coordinate input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a coordinate input device, and in particular, elastic wave vibration input from a vibrating pen is detected by a plurality of sensors provided on a vibration transmitting plate, and the vibration is transmitted from the vibrating pen. The present invention relates to a coordinate input device that detects the coordinates of a vibration input point by a vibrating pen based on the transmission time of elastic wave vibration input to a plate.

2. Description of the Related Art Conventionally, coordinate input devices using various input pens, tablets, and the like have been known as devices for inputting handwritten characters, graphics, and the like to a processing device such as a computer.
In this type of system, input image information including characters, figures, and the like is output to a display device such as a CRT display or a recording device such as a printer.

The following various methods are known for detecting the coordinates of a tablet of this type of device.

1) A method of detecting a change in resistance value of a sheet material disposed opposite to a resistance film.

2) A method of detecting electromagnetic or electrostatic induction of a conductive sheet or the like arranged opposite to each other.

3) A method of detecting ultrasonic vibration transmitted from the input pen to the tablet.

[Problems to be Solved by the Invention] However, these conventional devices have the following drawbacks.

That is, in the above-mentioned type using the resistance film, the uniformity of the resistor directly influences the accuracy of the figure input, so that a resistor having particularly excellent uniformity is required, which is very expensive. Further, since two resistance films for the x-coordinate and the y-coordinate are required, there is a drawback that the transparency is lowered.

Next, the electromagnetic induction type is not transparent because the electric wires are arranged in a matrix, and is not suitable for being used by being piled up on a document, a display or the like.

Furthermore, in the conventional ultrasonic coordinate input device, the delay time until the vibration generated by the input pen propagates through the propagation medium and reaches the conversion element is detected. It is necessary to know the reference time (for example, the time when the vibration occurs in the input pen) for detecting, and it is necessary to constantly input the information into the circuit that detects the arrival delay time.

Therefore, the input pen is connected to the main body by a cable or the like, and when inputting characters, figures and the like using this coordinate input device, the operability is very poor. Further, when the signal is transmitted by radio waves or the like, it is necessary to incorporate a transmitter or the like in the pen, and it is difficult to achieve the same shape, weight, and operability as those of ordinary writing instruments.

However, if the ultrasonic method overcomes the above problems, it does not have the drawbacks of the other methods described above, and since the mechanical structure is relatively simple, a low cost device can be provided. Therefore, it is an object of the present invention to realize a wireless input pen, which does not need to exchange any signal with a tablet side, in a coordinate input device using ultrasonic vibration.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, the elastic wave vibration input from the vibrating pen is detected by a plurality of sensors provided on the vibration transmitting plate, and the vibrating pen is used to detect the elastic wave vibration. In a coordinate input device that obtains the vibration transmission distance based on the transmission time of the elastic wave vibration input to the vibration transmission plate and detects the coordinates of the vibration input point by the vibrating pen, a plurality of vibrations with different sound speeds propagating on the vibration transmission plate. A configuration is adopted that includes a detection unit that detects a wave, a detection unit that detects a difference in arrival time of a plurality of vibration waves having different sound speeds, and a derivation unit that derives a vibration input point from the detected time difference.

[Operation] According to the above configuration, by detecting the difference in arrival delay time of the transverse wave component and the longitudinal wave component having different propagation velocities, the vibration transmission time from the input point to the vibration sensor, that is, the transmission distance is determined, and Coordinates can be calculated without the need for input timing information.

[Examples] Hereinafter, the present invention will be described in detail based on examples shown in the drawings.

FIG. 1 shows the structure of an information input / output device adopted by the present invention. The information input / output device of FIG. 1 causes the input tablet composed of the vibration transmission plate 8 to input coordinates by the vibrating pen 3, and the display device 11 is composed of a CRT which is arranged on the input tablet according to the input coordinate information. The input image is displayed on.

The reference numeral 8 in the drawing denotes a vibration transmission plate made of acrylic, glass plate or the like, which transmits vibration transmitted from the vibration pen 3 to three vibration sensors 6 provided at the corners. In this embodiment, the coordinate of the vibration pen 3 on the vibration transmission plate 8 is detected by measuring the transmission time of the ultrasonic vibration transmitted from the vibration pen 3 to the vibration sensor 6 via the vibration transmission plate 8.

The vibration transmitting plate 8 has its peripheral portion supported by an antireflection material 7 made of silicon rubber or the like in order to prevent the vibration transmitted from the vibrating pen 3 from being reflected at the peripheral portion and returning toward the central portion. ing.

The vibration transmission plate 8 is arranged on a display device 11 such as a CRT (or a liquid crystal display device) capable of dot display, and is adapted to perform dot display at a position traced by the vibration pen 3. That is, dots are displayed at the position on the display 11 corresponding to the detected coordinates of the vibrating pen 3, and the image composed of elements such as points and lines input by the vibrating pen 3 is written as if it were written on paper. It appears after the trajectory of the vibrating pen as you did.

Further, according to such a configuration, a menu is displayed on the display unit 11, and an input method such as selecting the menu item with the vibrating pen or displaying a prompt and touching the vibrating pen 3 at a predetermined position is used. It can also be used.

Vibration pen 3 for transmitting ultrasonic vibrations to the vibration transmission plate 8
Has a vibrator 4 formed of a piezoelectric element or the like inside, and transmits the ultrasonic vibration generated by the vibrator 4 to the vibration transmission plate 8 via the horn portion 5 having a sharp tip.

The vibrating pen 3 includes a drive circuit 2 for driving the vibrator 4.
Further, a power source B including a battery and the like is built in, and an electric synchronization signal is not exchanged with the input tablet or the apparatus main body side as in the conventional case.

The electric drive signal generated by the drive circuit 2 is converted into mechanical ultrasonic vibration by the vibrator 4 and transmitted to the diaphragm 8 via the horn unit 5.

Further, by setting the vibration frequency of the vibrator 4 as the resonance frequency of the vibrator 4, it is possible to perform efficient vibration conversion.

The vibration sensor 6 provided at the corner of the vibration transmission plate 8 is also composed of a mechanical-electrical conversion element such as a piezoelectric element. The output signal of each of the three vibration sensors 6 is input to the waveform detection circuit 9 and converted into a detection signal that can be processed by the arithmetic control circuit 1 in the subsequent stage, and the arithmetic control circuit 1 performs the measurement process of the vibration transmission time, The coordinate position of the pen 3 on the vibration transmission plate 8 is detected.

The detected coordinate information of the vibrating pen 3 is processed in the arithmetic and control circuit 1 according to the output system of the display 11. That is, the arithmetic control circuit controls the output operation of the display 11 via the video signal processing device 10 based on the input coordinate information.

FIG. 2A shows a vibrator driving waveform for driving the vibrator 4 in the vibrating pen 3. As shown in the figure, the vibrator driving circuit 2 inputs a rectangular wave pulse train of a predetermined length to the vibrator 4 at predetermined time intervals, and the vibration generated by the vibrator 4 is input to the vibration transmission plate 8.

This vibration is transmitted as elastic wave vibration on the vibration transmission plate 8 and detected by the vibration sensor 6. The output waveform of the vibration sensor 6 is shown in FIG.

Here, the elastic wave propagating in the elastic medium is composed of a longitudinal wave component and a transverse wave component. These components have different propagation speeds in the medium even if they have the same frequency. For example, comparing the longitudinal wave and the plate wave whose main component is the transverse wave, the propagation speed of the latter is almost half that of the former.

Therefore, as shown in the figure, the detection signal waveform is composed of the waveform WL of the longitudinal wave that first reaches the sensor and the waveform WS whose main component is the transverse wave having a slow propagation velocity. Here, the propagation velocity of the longitudinal wave is VL, and the propagation velocity of the transverse wave whose main component is the transverse wave is VS.

If the time required for both waves to reach one of the vibration sensors 6 from the vibration pen 3 is tL and tS, and the distance between the vibration pen 3 and the vibration sensor is d, then Δt = tS-tL (Δt: Difference in arrival time) (1) d = VL ・ tL = VS ・ tS = VS ・ (tL + Δt) (2) From the above equation, VL ・ tL = VS ・ (tL + Δt) (VL-VS) ・tL = VS ・ Δt This equation (3) shows that it is not necessary to know the vibration input timing of the vibration pen 3 as well as in the conventional case, if the arrival time difference between the longitudinal wave component and the transverse wave component and their transmission speeds are known in advance.

Therefore, the longitudinal wave propagation velocity on the vibration transmission plate 8 is set in advance.
If the VL and the shear wave propagation velocity VS are measured and stored in a memory such as a ROM, the distance between the vibration sensor 6 and the vibration pen 3 can be obtained by the equation (2).

From the above, the signal waveform detection circuit 9 may be composed of a waveform processing circuit and a timer circuit that detect the arrival timing of the first longitudinal wave component and the next transverse wave component from the output of the vibration sensor 6 and obtain the time difference between them. Recognize.

FIG. 3 shows a time chart of signal processing performed in the signal waveform detection circuit 9.

In the figure, reference numeral 31 is a drive waveform for driving the vibrator in the vibrating pen, and reference numeral 32 is a detection signal waveform when the drive transmitted through the vibration transmission plate is detected by the vibration sensor 6. Reference numeral 34 indicates an envelope of the detection signal waveform.

The leading wave of the longitudinal wave can be detected by detecting the rising edge of the detected waveform, but the leading portion of the plate wave whose main component is the transverse wave is superposed on the longitudinal wave, so that the leading wave cannot be specified. Therefore, the envelope peak of the entire waveform of the transverse wave component having a large amplitude is treated as the arrival timing of the transverse wave.
(Therefore, the arrival time is t's) Therefore, the signal waveform detection circuit 9 specifically has a circuit for detecting the rising edge of the waveform such as a comparator and an envelope peak detection circuit. Symbols in FIG. 3
Reference numerals 33 and 34 respectively indicate the timings of the detection pulses output by the rising edge detection circuit and the envelope peak detection circuit.

Further, the signal waveform detection circuit 9 has a timer circuit for obtaining the time difference Δt ′ between these detection pulses.

In this way, the time difference Δt ′ is obtained, but since Δt ′ is not obtained from the leading wave of the transverse waves, it is not a true arrival time difference. The true arrival time difference Δt is obtained by Δt = Δt′−α (4). α is a constant, and can be calculated by theoretically obtaining Δt based on the material of the vibration transmission plate 8 at a certain distance and comparing with Δt ′ output at that distance.

The signal waveform detection circuit 9 outputs the above Δt or Δt ′ to the arithmetic control circuit 1 as a latch value of a timer counter or the like. The arithmetic control circuit 1 can calculate the linear distance from the input point to the vibration sensor 6 by using the speeds of the longitudinal and transverse wave components, which are constants, based on this time value based on the equation (2), and further calculate the orthogonal coordinate value based on this. Obtainable.

When the three vibration sensors 6 at the corners of the vibration transmission plate 8 are arranged at the positions S1 to S3 as shown in FIG. 4, the linear distances d1, d2, d3 from the input point to the vibration sensor 6 are (2) If calculated based on the formula, the vibration pen 3
The position P coordinate (x, y) of can be obtained from the Pythagorean theorem as follows.

x = X / 2 + (d1 + d2) (d1-d2) / 2X (5) y = Y / 2 + (d1 + d3) (d1-d3) / 2Y (6) where X and Y are the positions of S2 and S3. This is the distance along the X and Y axes between the vibration sensor 6 and the sensor at the origin (position S1).

As described above, the position coordinates of the vibrating pen 3 can be detected. By repeating the above process, the input coordinates can be sequentially detected in real time.

As described above, according to the present embodiment, since the coordinate calculation can be performed without the detection device side having to know the input timing of the vibrating pen, timing information is transmitted and received between the vibrating pen and the device main body side having the vibration transmission plate. The vibrating pen can be made wireless and the operability at the time of input can be significantly improved.

Although the vibration sensor 6 is mounted on the vibration transmission plate 8 in the present embodiment described above, it may be mounted on the side surface (the plate thickness direction) of the vibration transmission plate 8 (see 6B in FIG. 5). The detected signal waveform obtained at this time has a larger amplitude in the longitudinal wave portion having a higher speed, and in this case, the head wave of the longitudinal wave can be detected more easily due to problems such as the S / N ratio.

In the above, it was considered to detect two waveform components from the output of one sensor. For example, as shown in FIG. 5, a sensor 6A for detecting a transverse wave and a sensor 6B for detecting a longitudinal wave are provided on the vibration transmission plate 8. Attach to the front or back and side,
You may make it detect each component from these sensors.

These vibration sensors 6A and 6B consist of piezoelectric elements,
The polarization direction is parallel to the cylinder axis, and the mode is such that voltage is mainly output with respect to axial displacement. Therefore, the sensor 6A outputs a transverse wave larger than the longitudinal wave, and the sensor 6B outputs a longitudinal wave component larger than the transverse wave. According to this method, the arrival time difference can be calculated directly by detecting the peak value of each component.

In the above, the transparent vibration transmission plate was used to describe the device that is used by overlapping it with the display or the original.However, if it is not necessary to use it with the display or the original, use an opaque metal or other material. You can use it.

[Effects of the Invention] As is apparent from the above description, according to the present invention, the elastic wave vibration input from the vibrating pen is detected by the plurality of sensors provided on the vibration transmitting plate, and the vibration pen transmits the vibration transmitting plate. In a coordinate input device that finds the vibration transmission distance based on the transmission time of the elastic wave vibration input to the device and detects the coordinates of the vibration input point by the vibrating pen, a plurality of vibration waves with different sound speeds propagating on the vibration transmission plate are detected. Of the sound velocity, the detection means for detecting the arrival time difference of the plurality of vibration waves having different sound speeds, and the derivation means for deriving the vibration input point from the detected time difference. By detecting the arrival time difference of a plurality of different vibration waves, the vibration transmission time from the input point to the vibration sensor, and thus the transmission distance, can be determined. Therefore, since it is not necessary to know the vibration input timing information of the vibrating pen, it is possible to omit the signal transfer between the vibrating pen and the device main body or the input tablet, and it is possible to make the vibrating pen wireless and to significantly improve the operability of the device. There is an excellent effect that it can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory view showing the configuration of an information input / output device adopting the present invention, FIG. 2 (A) is an explanatory view showing the vibrating pen of FIG. 1 and an input vibration waveform by the vibrating pen, FIG. 2 ( B) is a waveform diagram showing the waveform detected by the vibration sensor, FIG. 3 is a waveform diagram for explaining the operation and configuration of the signal waveform detection circuit, and FIG. 4 is an explanatory diagram showing the arrangement of the vibration sensor. The drawing is an explanatory view showing the arrangement of vibration sensors in different embodiments. 1 ... Arithmetic control circuit, 2 ... Oscillator drive circuit 3 ... Vibration pen, 4 ... Oscillator 5 ... Hall part 6, 6A, 6B ... Vibration sensor 8 ... Vibration transmission plate, B ... Power supply 10 …… Video signal processor 11 …… Display

(72) Inventor Shinnosuke Taniishi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Noriyuki Suzuki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Jun Tanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yuichiro Yoshimura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (1)

(57) [Claims] An elastic wave vibration input from a vibrating pen is detected by a plurality of sensors provided on a vibration transmission plate, and a vibration transmission distance is calculated based on a transmission time of the elastic wave vibration input from the vibrating pen to the vibration transmission plate. In the coordinate input device for detecting the coordinates of the coordinate input point by the vibrating pen, the detection means for detecting a plurality of vibration waves having different sound speeds propagating on the vibration transmission plate, and the arrival of the plurality of vibration waves having different sound speeds. A coordinate input device comprising: a detection unit that detects a time difference, and a derivation unit that derives a vibration input point from the detected time difference.