JPH06324792A - Coordinate input device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a coordinate input device in which the sensor is firmly fixed and which is highly accurate and is not easily affected by the environment. [Structure] Sensors 6 are attached to four corners of a vibration transmission plate 8 and are pressed against the vibration transmission plate 8 by an FPC (flexible printed circuit). One electrode of the sensor is connected to the FPC and then to the electrode printed on the vibration transmission plate 8. At this connecting portion, the FPC is fixed to the plate 8 by adhesion or the like. At this time, if the bonded portion is set in a direction that the sensor 6 does not want to pick up, vibration from that direction can be suppressed. Further, by covering the sensor, the sensor can be protected from dust and the like, and if it is connected as a conductor to the ground potential, it can be used as an electric shield.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 the vibration transmitting plate, and elasticity input from the vibrating pen to the vibration transmitting plate is detected. The present invention relates to a device that detects the coordinates of a vibration input point by a vibrating pen based on the transmission time of wave vibration.

[0002]

2. Description of the Related Art An ultrasonic coordinate input device is a method of calculating a position coordinate by detecting a delay time of a wave propagating on a vibration transmitting plate which is an input surface. Since no work such as electric wires is applied,
It is possible to provide an inexpensive device. Moreover, if a transparent plate glass is used for the vibration transmitting plate, a coordinate input device having higher transparency than other methods can be constructed.

In such a coordinate input device, a piezoelectric element such as PZT is used as a sensor for detecting vibration. As a method of extracting a signal from this sensor, Japanese Patent Application No. 4-2368, which is a prior application by the applicant of the present application,
No. 07 discloses a means for extracting a signal from an electrode of a sensor by using an FPC (Flexible Print Circuit). Further, in Japanese Patent Application No. 4-263407, a signal is used by using a leaf spring as an electrode of the sensor. A method of removing is disclosed.

[0004]

In such a conventional method, in the method of pressing and fixing the FPC to the sensor with a leaf spring or solder or the like to take out a signal, the cost of the leaf spring itself and the soldering process are taken into consideration. The manufacturing cost was high.

Further, the vibration propagating through the vibration transmitting plate is reflected by the end face of the vibration transmitting plate, and the sensor detects the reflected vibration and the non-reflected vibration. However, there was a problem that

Further, in the conventional structure, since the sensor is exposed, it is apt to be adversely affected by electromagnetic waves and moisture in the environment.

The present invention has been made in view of the above-mentioned conventional example, and an object thereof is to provide a coordinate input device which is not easily affected by the environment and which is highly accurate.

[0008]

[Means for Solving the Problems] and

To achieve the above object, the coordinate input device of the present invention has the following structure.

Vibration generating means for generating vibration, vibration transmitting means for transmitting the vibration generated by the vibration generating means, detecting means for detecting the vibration of the vibration transmitting plate means, and one end of the detecting means. A plate member fixed to the vibration transmitting plate by a fixing portion at an end, and a unit for calculating coordinates of a position where the vibration is generated by the vibration generating unit based on the vibration detected by the detecting unit.

[0010]

First Embodiment FIG. 1 shows the structure of a coordinate input device according to this embodiment. In the figure, reference numeral 1 denotes an arithmetic control circuit for controlling the entire apparatus and calculating a coordinate position. Reference numeral 2 denotes a vibrator drive circuit for vibrating the pen tip inside the vibrating pen 3. Reference numeral 8 is a vibration transmission plate made of a transparent member such as acrylic or glass plate. Coordinate input by the vibration pen 3 is performed by touching the vibration transmission plate 8. In practice, the vibrating pen 3 is used to designate the area within the area A (hereinafter referred to as the effective area) indicated by the solid line in the figure. A vibration isolator 7 is provided on the outer periphery of the vibration transmission plate 8 to prevent (reduce) the reflected vibration from returning to the central portion, and the vibration sensors 6a to 6b that convert mechanical vibrations into electric signals. 6d is fixed, and the detection signal is taken out by the FPC 12.

Reference numeral 9 denotes a signal waveform detection circuit for outputting to the arithmetic and control circuit 1 a signal indicating that vibration has been detected by each of the vibration sensors 6a to 6d. Reference numeral 11 is a display capable of displaying a dot unit of the liquid crystal display, and is arranged behind the vibration transmission plate. Then, by driving the display drive circuit 10, it is possible to display a dot at a position traced by the vibrating pen 3 and see it through the vibration transmission plate 8 (made of a transparent member).

The vibrator 4 built in the vibrating pen 3 is driven by the vibrator driving circuit 2. The drive signal of the vibrator 4 is supplied as a low-level pulse signal from the arithmetic control circuit 1, amplified by the vibrator drive circuit 2 with a predetermined gain, and then applied to the vibrator 4.

The electric drive signal is converted into mechanical ultrasonic vibration by the vibrator 4, and is transmitted to the vibration transmission plate 8 via the pen tip 5.

Here, the vibration frequency of the vibrator 4 is selected to a value capable of generating a plate wave on the vibration transmission plate 8 such as glass. Further, when driving the vibrator, the vibration transmission plate 8 is moved to the position shown in FIG.
The mode that vibrates in the vertical direction is selected. Further, by setting the vibration frequency of the vibrator 4 to the resonance frequency including the pen tip 5, it is possible to perform efficient vibration conversion.

The elastic wave transmitted to the vibration transmission plate 8 as described above is a plate wave, and has an advantage that it is less susceptible to damages and obstacles on the surface of the vibration transmission plate as compared to surface waves. . <Explanation of Arithmetic Control Circuit> In the above-described configuration, the arithmetic control circuit 1 outputs a signal for driving the vibrator 4 in the vibrator driving circuit 2 and the vibrating pen 3 at every predetermined cycle (for example, every 5 ms), and the inside thereof. Starts timing by a timer (consisting of a counter). Then, the vibration generated by the vibrating pen 3 is delayed according to the distance to the vibration sensors 6a to 6d.

The vibration waveform detection circuit 9 includes vibration sensors 6a-
The signal from 6d is detected, and a signal indicating the vibration arrival timing to each vibration sensor is generated by the waveform detection processing described later. The arithmetic control circuit 1 inputs this signal for each sensor, and each vibration sensor The vibration arrival times of 6a to 6d are detected, and the coordinate position of the vibrating pen is calculated.

The arithmetic control circuit 1 drives the display drive circuit 10 based on the calculated position information of the vibrating pen 3 to control the display on the display 11.
Alternatively, the coordinates are output to an external device by serial or parallel communication (not shown).

FIG. 3 is a block diagram showing a schematic structure of the arithmetic and control circuit 1 of the embodiment. The respective constituent elements and the operation outline thereof will be described below.

In the figure, 31 is a microcomputer for controlling the arithmetic control circuit 1 and the coordinate input device as a whole, and an internal counter, a ROM storing operation procedures, a RAM used for calculations and the like, and a nonvolatile memory storing constants and the like. It is composed of a sex memory.

Reference numeral 33 is a timer (not shown) for counting a reference clock, which is for starting the vibrator driving circuit 2 to start driving the vibrator 4 in the vibrator pen 3. When a signal is input, the timing starts. As a result, the start of timing and the vibration detection by the sensor are synchronized, and the delay time until the vibration is detected by the sensors (6a to 6d) can be measured.

The circuits that are the other constituent elements will be described in order.

The vibration arrival timing vibrations from the vibration sensors 6a to 6d output from the vibration wave detection circuit 9 are transmitted through the detection signal input port 35 to the latch circuits 34a to 34d.
Entered in.

Each of the latch circuits 34a to 34d has
It corresponds to each of the vibration sensors 6a to 6d, and when a timing signal from the corresponding sensor is received, the measured value of the timer 33 at that time is latched. When the determination circuit 36 determines that all the detection signals have been received in this way, it outputs a signal to that effect to the microcomputer 31.

When the μ computer 31 receives the signal from the judgment circuit 36, the vibration arrival time from the latch circuits 34a to 34d to the respective vibration sensors is read from the latch circuit, a predetermined calculation is performed, and the vibration transmission plate 8 is carried out. The coordinate position of the upper vibrating pen 3 is calculated. And I / O port 3
By outputting the calculated coordinate position information to the display drive circuit 10 via 7, the display 11
A dot or the like can be displayed at the position corresponding to.
Alternatively, the coordinate value can be output to an external device by outputting the coordinate position information to the interface circuit via the I / O port 37. <Description of Vibration Propagation Time Detection (FIGS. 4 and 5)> The principle of measuring the vibration arrival time to the vibration sensor 3 will be described below.

FIG. 4 is a diagram for explaining the detection waveform input to the vibration waveform detection circuit 9 and the measurement process of the vibration transmission time based on the detection waveform. Note that the vibration sensor 6a will be described below, but the other vibration sensors 6b, 6c, 6
The same is true for d.

It has already been described that the measurement of the vibration transmission time to the vibration sensor 6a is started at the same time when the start vibration is output to the vibrator drive circuit 2. At this time, the drive signal 41 is applied from the vibrator drive circuit 2 to the vibrator 4. The ultrasonic vibration transmitted from the vibration pen 3 to the vibration transmission plate 8 by the signal 41 progresses for a time tg corresponding to the distance to the vibration sensor 6a, and then is detected by the vibration sensor 6a. The signal indicated by 42 in the figure shows the signal waveform detected by the vibration sensor 6a.

Since the vibration used in this embodiment has a waveform, the relationship between the envelope 421 and the phase 422 of the detected waveform with respect to the propagation distance within the vibration transmission plate 8 is that the transmission distance changes during vibration transmission. It changes accordingly. Here, the traveling speed of the envelope 421, that is, the group speed is Vg, and the phase speed of the phase 422 is Vp. The distance between the vibration pen 3 and the vibration sensor 6a can be detected from the group velocity Vg and the phase velocity Vp.

First, focusing only on the envelope 421, its velocity is Vg, and when a point on a certain specific waveform, for example, a peak such as an inflection point or a signal shown in FIG. 43 is detected, the vibration pen 3 and the vibration sensor are detected. The distance between 6a is given by d = Vg · tg (1), where the vibration transmission time is tg. This formula relates to one of the vibration sensors 6a, but the other three vibration sensors 6b are represented by the same formula.
The distance between 6d and the vibrating pen 3 can be similarly expressed.

Further, in order to determine the coordinates with higher accuracy, processing is performed based on the detection of the phase signal.

The time from the specific detection point of the phase waveform signal 422, for example, the vibration application to the zero cross point after a certain predetermined signal level 46, is tp45 (a window signal 44 of a predetermined width is generated for the signal 47, (Obtained by comparing with the signal 422), the distance between the vibration sensor and the vibration pen is d = n · λp + Vp · tp (2). Here, λp is the wavelength of the elastic wave, and n is an integer.

From the above equations (1) and (2), the above integer n
Is expressed as n = [(Vg · tg−Vp · tp) / λp + 1 / N] (3).

Here, N is a real number other than "0", and an appropriate value is used. For example, if N = 2, then n can be set to be a negative value if there is a variation such as tg within ± 1/2 wavelength. By substituting n obtained as described above into the equation (2), the distance between the vibration pen 3 and the vibration sensor 6a can be accurately measured. The generation of the signals 43 and 45 for measuring the above-described two vibration transmission times tg and tp is performed by the vibration waveform detection circuit 9, which is configured as shown in FIG. FIG. 5 is a block diagram showing the configuration of the vibration waveform detection circuit 9 of the embodiment.

In FIG. 5, the output signal of the vibration sensor 6a is amplified to a predetermined level by the preamplifier circuit 51. An extra frequency component of the detection signal is removed from the amplified signal by the band-pass filter 511, and the amplified signal is input to the envelope detection circuit 52 including, for example, an absolute value circuit and a low-pass filter. Only the envelope of the detection signal is detected. Is taken out. The timing of the envelope peak is detected by the envelope peak detection circuit 53. In the peak detection circuit, a signal tg (signal 43 in FIG. 4) which is an envelope delay time detection signal having a predetermined waveform is formed by the tg signal detection circuit 54 composed of a mono-multivibrator or the like, and is input to the arithmetic control circuit 1.

On the other hand, 55 is a signal detection circuit, which detects the envelope signal 42 detected by the envelope detection circuit 52.
The pulse signal 47 of the portion exceeding the threshold signal 46 of the predetermined level in 1 is formed. 56 is a monostable multivibrator, which opens the gate signal 44 of a predetermined time width triggered by the first rising edge of the pulse signal 47. Reference numeral 57 denotes a tp comparator, which detects the first rising zero-cross point of the phase signal 422 while the gate signal 44 is open, and supplies the phase delay time signal tp45 to the arithmetic control circuit 1. The circuit described above is the vibration sensor 6
The same circuit is provided for other vibration sensors. <Description of Circuit Delay Time Correction> The vibration transmission time latched by the latch circuit includes the circuit delay time et and the phase offset time toff. The error caused by these is always included in the same amount when the vibration is transmitted from the signal pen 3 to the vibration transmission plate 8 and the vibration sensors 6a to 6d.

Therefore, for example, from the position of the origin O in FIG.
For example, the distance to the vibration sensor 6a is R1 (= X / 2), and the actually measured vibration transmission time from the origin O to the sensor 6a measured by inputting with the vibration pen 3 at the origin O is tg.
z ', tpz', and tgz, tpz as true transmission times to the origin O color sensor, these are related to the circuit delay time et and the phase offset toff: tgz '= tgz + et (4) tpz' = tpz + et + toff ... There is a relationship of (5).

On the other hand, the measured value tg 'at an arbitrary input point P
Similarly, tp ′ is tg ′ = tg + et (6) tp ′ = tp + et + toff (7) When the difference between these (4), (6), (5) and (7) is calculated, tg'-tgz '= (tg + et)-(tgz + et) = tg-tgz (8) tp'-tpz Since '= (tp' + et + toff)-(tpz + et; toff) = tp-tpz (9), the circuit delay time et and the phase offset toff included in each transmission time are removed, and from the position of the origin O. It is possible to obtain the difference in the true transmission delay time according to the distance from the position of the sensor 6a between the input points P as the starting point.
The distance difference can be obtained by using the equation (3).

Since the distance from the vibration sensor 6a to the origin O is stored in a nonvolatile memory or the like in advance and is known, the distance between the vibration pen 3 and the vibration sensor 6a can be determined. The other sensors 6b to 6d can be similarly obtained.

The measured values tgz 'and tpz' at the origin O are stored in the nonvolatile memory at the time of shipment,
The equations (8) and (9) are executed before the calculation of the equations (2) and (3), and highly accurate measurement can be performed. <Explanation of coordinate position calculation (FIG. 6)> Next, the vibrating pen 3 is actually used.
The principle of detecting the coordinate position on the vibration transmitting plate 8 by means of will be described.

Now, in the vicinity of the midpoint of four sides on the vibration transmission plate 8, 4
When the two vibration sensors 6a to 6d are provided at the positions S1 to S4, the linear distances de to dd from the position P of the vibrating pen 3 to the positions of the respective vibration sensors 6a to 6d are calculated based on the principle described above. You can ask. Further, the arithmetic control circuit 1 can obtain the coordinates (x, y) of the position P of the vibrating pen 3 from the Pythagorean theorem based on the linear distances da to dd as in the following equation.

X = (da + db) · (da−db) / 2X (10) y = (dc + dd) · (dc−dd) / 2Y (11) where X and Y are between the vibration pen sensors 6a and 6b, respectively. And the distance between the vibration sensors 6c and 6d.

As described above, the position coordinates of the vibrating pen 3 can be detected in real time. <Explanation of Signal Extraction Unit> FIGS. 7A and 7B show the FPC.
The relationship between the (Flexible Print Circuit) 12, the sensor 6, and the vibration transmission plate 8 is shown. The FPC 12 is provided with an electrode portion 12-A that is electrically connected to the sensor 6 and an adhesive portion 12-B that is attached to the vibration transmission plate 8. Electrode part 12-A
When the adhesive portion 12-B is attached to the vibration transmission plate 8, the adhesive portion 12-B is pressed against the electrode portion of the sensor 6, and the detection signal from the sensor 6 is taken out and transmitted to the preamplification circuit 51.
With such a configuration, members such as leaf springs can be omitted, and reliability, assembling property, etc. can be improved.

FIG. 7C shows an embodiment in which a sensor is provided at the corner of the vibration transmission plate 8. In this case, FPC1
As shown in the figure, the second adhesive portion 12-B is provided in the direction in which the end face reflection is incident on the sensor, and the adhesive portion 12- is provided on the input area side so that the direct wave is not affected.
B is not provided. A vibration-proof material is provided on the end surface of the transmission body 8 to prevent reflection, but an invalid area is required outside the input area in order to attenuate the vibration to a level that does not affect signal detection. By blocking the incidence of such reflection on the sensor by using the FPC adhesive portion 12-B, it is possible to obtain effects such as reduction of the invalid area and reduction of the vibration isolator.

Further, since the FPC has an adhesive portion in a specific direction with respect to the vibration transmission plate and is pressed against the vibration transmission plate 8, it is possible to eliminate the leaf spring, improve reliability and reduce cost. Further, by providing the adhesive portion in the path of the reflected wave on the vibration transmitting plate, the influence of the end face reflection can be reduced and the accuracy can be improved.

[0044]

[Second Embodiment] In the first embodiment, the adhesive portion is used for the reflected wave, but it is also possible to use the directivity control for the direct wave. In FIG. 8, unlike the above example, the sensor 6 is disposed near the center of the side, and in such a case, the sensor and the input area may be considerably close to each other. Since the level of vibration detection is determined by the distance between the sensor and the input point, the level difference between the vicinity of the sensor and the farthest point of the input area becomes considerably large, and it is necessary to considerably widen the dynamic range of the signal waveform detection circuit 9. is there.

On the other hand, as shown in FIG. 8, the FPC adhesive layer 12-B is applied to the central portion of the sensor and the input area. The vibration from the central part (A area) of the input area is attenuated according to the attenuation characteristics of the FPC and the adhesive when passing through the adhesive part. Since the input area peripheral portion (B area) is directly input to the sensor, no attenuation occurs. By adding non-uniformity of the input level (direction directivity) to the input area direction in this way, directivity can be added to the sensor, and the dynamic range required for the signal waveform detection circuit 9 is reduced. be able to. Therefore, the demands on the circuit are reduced, and the circuit configuration can be simplified.

In the above description, the adhesive portion is provided only on the input area side, but it is of course possible to provide the adhesive portion on the opposite side as well for preventing the reflected wave. Although the fixing will not be described in detail, the sensor and the FPC electrode may be configured to be in pressure contact with each other.

[0047]

[Third Embodiment] FIG. 9 shows a third embodiment of the present invention. The electrode of the sensor 6 on the vibration transmission plate 8 side is in contact with the conductive layer 13 provided on the vibration transmission plate 8 by printing or the like. Normally, this portion is set on the ground side, and also serves as a noise shield from the transmission plate 8 side.

Now, as shown in FIG. 9, a shield electrode 12-C larger than the FPC base material is provided on the upper side of the FPC 12 (the back side of the sensor electrode 12-A), and on the conductive layer 12-C and the transmission plate 8. It is possible to reduce malfunctions and the like due to the intrusion of electromagnetic noise and the like by configuring the electrode so as to be electrically connected to the print electrode and using the same potential as the print electrode 13 as a shield. Regarding contact, a conductive adhesive material or pressure contact may be used as long as it can be electrically conducted. In addition, the shield electrode is FPC
It may be partly larger than the base material, or may be configured to wrap around to the adhesive side. In addition, in the explanation of FIG.
Although a PC is used, it may be configured by a single-layer FPC and folded.

[0049]

[Fourth Embodiment] FIG. 10 shows a sensor 6 according to a fourth embodiment.
It is configured to surround the circumference of. In this way, the adhesive section 12-B of the FPC is provided around the sensor 6,
By covering the sensor 6 with, for example, when the sensor is arranged on the input surface, it is possible to escape from the sensor destruction due to mixing of foreign matter such as water. Further, by configuring the FPC base material with hardness, it becomes possible to protect the sensor from an external impact.

Naturally, it is possible and effective to combine the several embodiments described above.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device.

[0052]

As described above, the coordinate input device according to the present invention has the effects that it is not easily affected by the environment and that it is highly accurate.

As described above, an instruction is given by the vibration input pen on the basis of the delay time at which the elastic wave vibrations from the vibration transmission plate and the vibration input pen input on the vibration transmission reach the vibration detection means. The coordinate input device for calculating and outputting the coordinate position on the vibration transmitting plate, which has means for extracting the vibration from the vibration detecting means, wherein the extracting means has a specific direction with respect to the vibration transmitting plate. By having an adhesive portion and being pressed against the transfer means, it is possible to eliminate the leaf spring, improve reliability, and achieve a cost source.
Furthermore, the fixed portion of the signal extracting means is provided in the vibration reflection path of the vibration transmitting means, so that the influences of end face reflection, directivity, etc. are reduced and high precision is achieved.

Further, by fixing the fixing portion of the vibration extracting means so as to be electrically connected to the electrode portion provided in the vibration transmitting means, a shield effect can be obtained, and further, the signal extracting means. Since the fixed part is configured so as to cover the vibration detecting means, the sensor can be protected and a highly accurate coordinate input device can be provided.

[Brief description of drawings]

FIG. 1 is a block configuration of a coordinate input device.

FIG. 2 is a diagram showing a configuration of a vibrating pen.

FIG. 3 is a block diagram of an internal configuration of an arithmetic control circuit in the example.

FIG. 4 is a time chart of signal processing.

FIG. 5 is a block diagram of a signal detection circuit.

FIG. 6 is a diagram illustrating coordinate calculation of a coordinate input device.

FIG. 7 is an explanatory diagram of the first embodiment.

FIG. 8 is a diagram of a signal extracting unit having an adhesive portion in a reflection path.

FIG. 9 is an explanatory diagram of a shield.

FIG. 10 is an explanatory diagram of sensor protection.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 arithmetic control circuit, 2 oscillator drive circuit, 3 vibration input pen, 4 oscillator, 5 pen tip, 6a-6d vibration sensor, 7 vibration isolator, 8 vibration transmission plate, 9 signal waveform detection circuit, 12 FPC, 13 It is a printed electrode.

Front page continuation (72) Inventor Hajime Hajime 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yuichiro Yoshimura 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Katsuyuki Kobayashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (4)

[Claims] 1. A vibration generating means for generating vibration, a vibration transmitting means for transmitting the vibration generated by the vibration generating means, a detecting means for detecting the vibration of the vibration transmitting plate means, and one end of the detecting means. And a means for calculating the coordinates of the position where the vibration is generated by the vibration generating means based on the vibration detected by the detecting means, A coordinate input device comprising: 2. The fixing portion of the plate body is located between the detecting means and the vibration source of the vibration generating means and attenuates the vibration propagating to the detecting means.
The coordinate input device described. 3. The coordinate input device according to claim 1, wherein the plate body is a conductor and transmits an output signal from the vibration detecting means. 4. The coordinate input device according to claim 1, wherein the plate body is a conductor, covers the detection means, and is maintained at a ground potential.