JPS6314221A - Coordinate input device - Google Patents

Abstract

PURPOSE:To eliminate the waveform disorder of an electric signal obtained by a piezoelectric element for reception and to stabilize the electric signal by specifying a position with a coordinate input pen consisting of a vibration transmission part which resonates with the vibration frequency of a vibrating element. CONSTITUTION:A horn 3a has a straight part molded integrally, and a flange 12 is provided to the node position of vibrations and fixed to the holder 13 of the input pen 1 to transmit efficiently vibrations generated by the vibrating element 2. When a point on a coordinate input board 5 is specified with the input pen 1, the vibrating element 2 receives a signal from a pulse generator 10 to vibrate and the vibrations are transmitted to the horn 3a. Piezoelectric elements 7a-7c of a receiving element measure delay times respectively to calculate the coordnate position specified with the input pen 1. The horn 3a of the input pen 1 is made coincident with the driving frequency and the resonance frequency to the vibrating element 2 and an elastic wave of set frequency can be propagated to the vibration propagation body 5. Therefore, the electric signal has no waveform disorder and high-accuracy and high-resolution coordinate input can be performed.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a coordinate input pen, and particularly to a coordinate input pen used in a coordinate input device that propagates elastic waves and detects the position where the elastic waves are generated. .

[Prior Art] A coordinate input device using elastic waves uses a plurality of receiving elements (piezoelectric elements) fixed in advance to the coordinate input plate to adjust the intensity of elastic waves generated from an input pen and propagated. The position specified by the input pen was calculated by converting it into a corresponding electrical signal and measuring the delay time until the signal was detected.

[Problems to be Solved by the Invention] The input pen used here includes a vibrating element that vibrates in response to an electric signal, and a vibration transmitting part (which magnifies the vibration and transmits the vibration to the vibration propagation body). (hereinafter referred to as the horn), but the horn of conventional input pens is
Nothing was intended to resonate with the vibration wave number of the vibration element, and the vibration magnification rate was not taken into consideration.
This causes the waveform of the electrical signal converted by the three receiving elements to become undefined and distorted, resulting in negative effects such as poor accuracy and resolution when calculating coordinate positions.

Furthermore, since the input pen is small, it is extremely difficult to provide the support member on the inclined surface of the horn.

The present invention has been made in view of the above-mentioned prior art, and its object is to stabilize the electrical signal converted by the receiving element by providing a coordinate input pen equipped with a horn that resonates with the vibration of the vibrating element.

[Means for solving the problem] In order to solve this problem, the present invention has the following configuration.

That is, a vibrating element that receives a pulse signal of a predetermined period and vibrates in synchronization with the period, and a vibration that is connected to the vibrating element and resonates with the vibration, amplifies the vibration, and transmits the vibration to the pen tip. The vibration transmitting device includes a transmitting section and a support member that supports the vibration transmitting section on the housing of the input pen.

[Operation] In the configuration of the present invention, a position is specified using a coordinate input pen comprising a vibration transmitting section that vibrates in resonance with the frequency of the vibration element.

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, an overview of the coordinate input device in this embodiment will be explained.

FIG. 3 is a configuration diagram of the coordinate input device of this embodiment.

In the figure, reference numeral 1 denotes a vibrating pen (coordinate input pen), which includes a vibrating element 2 (see Fig. 2) that vibrates with a signal of a predetermined period from a pulse generator 10, and a vibration transmitting part (hereinafter referred to as (referred to as a horn) 3. 4 is a tablet-type signal input board, and 5 is a vibration propagation body.

6 is a contact point between the horn 3 and the vibration propagation body 5. Also,
78 to 7c are piezoelectric elements for vibration detection, which generate electric signals corresponding to the intensity of elastic waves. 8 is a lead wire; 9 (a vibration absorbing material for preventing the reflection of elastic waves; 11 is a material for instructing the pulse signal generator 10 to generate a pulse signal and inputting an electric signal from the lead wire 8; This is an amplification calculation circuit that detects position coordinates.When a coordinate position is detected, the position data is stored in a data storage area provided in the amplification calculation circuit 11, and is stored in a predetermined device (not shown) (host computer). or display device, etc.).

To explain the operation of the above-mentioned configuration, first, a start signal is output from the amplification calculation circuit 11 to the pulse generator 10, and in response, the pulse generator 10 generates a pulse electric signal. The resolution increases as this frequency increases, but
300 to 500 KHz is appropriate in that the attenuation rate also increases. In response to this electric signal, the vibrating element 2 of the vibrating ben 1
expands and contracts (vibrates) with the frequency of vibration. This vibration is magnified by the horn 3, and at the contact point 6 the vibration propagator S
The vibration is transmitted as a plate wave elastic wave.

Note that the material of the vibration propagation body 5 may be a transparent plate such as glass or acrylic.

Now, the propagated plate wave elastic wave is detected as piezoelectric chamber pressure by three piezoelectric elements 7a to 7c provided for vibration detection, and is outputted to the amplification calculation circuit 11 via the lead wire 8. Also, at this time, the delay time required for vibration propagation is detected in synchronization with the start signal generated from the amplification calculation circuit 11. The above operation is repeated, for example, 50 to 150 times per second, and the piezoelectric elements 7a for vibration detection at three locations are obtained.
The position coordinates of the contact point 6 of the vibrating vent 1 are calculated using the delay time at 7c.

Note that this calculation method is shown below.

As shown in FIG. 4, the coordinate position of the contact point 6 of the vibrating ben 1 with the vibration propagating body 5 is (x, y), and the coordinates Pa to Pc of the three piezoelectric elements 7a to 7c for image capturing and detection are respectively Pa (Xi, xl) = (0, O) Pb (x2.x2) = (x2.0) Pc (X3.
When X3)=(0, y3), the position coordinates (x, y) of the vibrating vent 1 can be obtained as shown in the following equation.

However, the coordinate position of the contact point 6 is detected by performing calculations of t1 to t3: propagation time of the elastic wave, V: propagation speed of the elastic wave, or more in the amplification calculation circuit 11.

Note that when the vibration in the vibration propagation body 5 reaches the vibration absorber 9, the amplitude of the elastic wave is attenuated here. In this embodiment, the vibration absorbing material 9 is made of silicone rubber mixed with metal powder in order to have a large attenuation rate and match the natural acoustic impedance with glass, but the material is not limited to this. It's not a thing. Furthermore, regarding the plate thickness of the vibration propagation body 5, it is appropriate that the thickness be 0.3 to 2.0 mm. This is because as the plate thickness decreases, the amplitude of the propagated and detected elastic waves increases, but the strength of the material decreases.

The horn 3 of the vibrating ben 1 in the coordinate input device as described above
This will be explained using FIG. 5 as an example.

In the figure, the horn 3b has a conical shape and is made of aluminum, for example.

In addition, in the figure, A is the large end face of the horn 3b, and its diameter is
, B is the small end face with a diameter D2, and the length of the end face is the length of the horn 3b. Here, the resonance frequency f is 400 [K)1
21, D, = 5.0 [mml, D 2110.5 [
mml, l·8.15 [mml, which is derived from the resonance conditional expression (1) shown below.

However, α=wavelength constant (=W/C).

If the diameter D1 of the large end surface A becomes close to half a wavelength or larger, radial resonance may occur, so it should not be made too large.

Furthermore, a vibration element 2 that resonates at 300 to 500 [ozl]
In relation to the diameter, Dl is preferably around 5 [mm1].

Further, the magnification ratio of the horn 3b is determined by DI/D2, which in this case is approximately 4.3.

In any case, if this horn 3b is used to form the seat drifting chamber 1, it will resonate with the vibration period of the vibration element 2.

In addition, in the above explanation, the case where the horn 3 is applied to a conical-shaped horn 3b has been explained, but for example, as shown in FIG. 1(a).
, The cross-sectional shape in the longitudinal direction may be an exponential function, as shown in the horn 3a shown in FIG.

In the figure, A is the large end surface of the horn 3a, B is the small end surface of the horn 3a, C is the tangential straight line, Dl is the diameter of the large end surface of the horn 3a, D2 is the diameter of the small end surface of the horn 3a, and lx is the horn The length of the straight part C of the horn 3a, the vertical part 2 is the length of the exponential part of the horn 3a, X is the predetermined distance from the big end surface A, and D
X is the diameter of the horn 3a at the distance mx, and 12
is a flange that supports the horn 3a on the input ben 1 (a support part that supports the input ben 1).

In addition, since the horn of this embodiment is small, if there is no straight part C as shown in horn 3b in Fig. 5, a flange must be attached to the inclined surface, which is extremely difficult to process. This increases the cost and is not the intention of this embodiment.

Therefore, the horn 3a in this embodiment has a flange 12
The position of is located at the node of vibration amplitude of the straight part C (
Figure 1(b)).

The reason for this is that supporting the nodes of the vibration width requires the least loss of imaging energy and is the most efficient. Further, the horn 3a and the straight portion C are integrally molded, and the flange 12 is provided at the node position of the vibration amplitude. This is because processing is easy and costs can be reduced in this way.

Now, in the horn 3a of FIG. 1(a), if the resonant frequency f is 400 [H4F,
, 02-0.5[mml, l 1-4.0[mml
.

fl 2-5.15 [mml, Dx-D, e-θX
[β (index) of mml is 0.374. This numerical value can be derived from the resonance conditional expression (2), the expression (3) for determining the position XN of the vibration nodal surface, and the expression (4) for determining the amplitude expansion rate. The main symbols used here are summarized as follows.

$1: Area of the large end of the horn S2: Area of the small end of the horn Dl: Diameter of the large end of the horn D2: Diameter of the small end of the horn 1; Length of the straight part of the horn Statement 2: Exponential part of the horn Length α: Wavelength constant = w/c C: Sound velocity in the horn material (longitudinal wave in the alumina rod +
5.04x 103 [m/5eclf: Resonant frequency of the horn W: Resonant angular wave number of the horn = 2πf ) in the equation α=W/c.

jan(axs)=1/jan(ai+)−(3
) (depending on the straight part when α dan, 〉π/2) Also, Fig. 2 shows the case where the horn 3a supporting the flange 12 shown in Fig. 1 is fixed to the holder (housing) 13 of the input pen 1. FIG.

Hold this input bench 1 in your hand and use the coordinate input board (vibration propagator 5
) above. The vibration element 2 vibrates in response to a signal from the pulse generator 10, and the vibration is transmitted to the horn 3a, and the piezoelectric elements 7a to 7b, which are receiving elements, measure the respective delay times, thereby allowing the input pen 1 to The specified coordinate position will then be calculated.

As explained above, according to this embodiment, it is possible to match the driving frequency of the horn of the input pen with the resonance frequency of the vibration element (vibration element 2), and to vibrate the elastic wave of the set frequency. It becomes possible to propagate it to a propagating body. Therefore, there is no disturbance in the waveform of the electric signal converted by the receiving piezoelectric element, and a highly accurate and high resolution coordinate input device can be formed.

In addition, by integrally molding a straight part on the horn, providing flanges at the vibration node positions, and fixing the input pen to the holder, it becomes possible to efficiently transmit the vibrations emitted from the vibrating element. In addition, since pen pressure is not directly applied to the vibrating element, there is no influence on the vibration amplitude, and disturbances in the electrical signal converted by the receiving element can be eliminated, creating a high-resolution, high-precision coordinate input device. It becomes a coordinate input pen.

In addition, by attaching the flange to the straight part that is integrally molded with the horn, instead of attaching the flange to the inclined part of the horn, it is possible to increase workability and reduce costs, and the flange can be made thinner. By doing so, it becomes possible to improve the vibration transmission efficiency.

In this embodiment, it has been described that the horn is made of aluminum, but it may also be made of aluminum whose surface has been strengthened or other metals, but it is also possible to make it by using a piezoelectric element or a vibration propagator. When is made of glass, the material is not limited to this as long as the characteristic impedance is close to that of glass.

Further, in this embodiment, the flange 12 and the horn 3a are separate bodies, but by molding them, the horn can be fixed to the holder accurately and stably, and at a low cost. It has the advantage of being processable.

In addition, in this example, in order to match the driving frequency and the vibration frequency (resonance), two horn shapes, conical and exponential, were explained. A conical horn type, a step conical type, a step nix bone type, a simple step type, etc. may be used.

In addition, in this example, the explanation was made so that the horn resonates at 1/2 wavelength, but when the horn is combined with the vibrating element, the total resonance is 1/2.
It goes without saying that the shape may be changed depending on the wavelength, and the shape also changes depending on the value of the driving frequency.

The following is a blank space [Effects of the Invention] As explained above, according to the present invention, the vibration transmission section of the coordinate input pen resonates with the vibration element, thereby making it possible to propagate an elastic wave of a set frequency to the vibration propagation body. becomes. Therefore, there is no disturbance in the waveform of the electrical signal converted by the receiving piezoelectric element, resulting in a coordinate input pen forming a highly accurate and high resolution coordinate input device.

[Brief explanation of the drawing]

Fig. 1(a) is a diagram showing the shape of the horn of this embodiment, Fig. 1(b) is a diagram showing the horn of this embodiment with a flange attached, and Fig. 2 is an input pen of this embodiment. 3 is an overall block diagram of the coordinate input device of this embodiment, FIG. 4 is a diagram showing the relationship between the vibrating pen and the delay time until detecting the elastic force, and FIG. 5 is a cross-sectional view of the vicinity of the pen tip. FIG. 3 is a diagram showing another horn shape of this embodiment. In the figure, 1... input ben, 2... vibration element, 3.3a
, 3b...Horn, 4...Signal input board, 5...Vibration propagation body, 6...Contact point, 7a-7C...Piezoelectric element for detecting elastic waves, 8...Lead wire , 9... Imaging absorbing material, 10... Pulse signal generator, 11... Width calculation circuit.

Claims (4)

[Claims] (1) A vibrating element that receives a pulse signal of a predetermined period and vibrates in synchronization with the period, and is connected to the vibrating element, resonates with the vibration, amplifies the vibration, and transmits the vibration to the pen tip. A coordinate input pen comprising: a vibration transmission section; and a support member that supports the vibration transmission section on a housing of the input pen. (2) A patent claim characterized in that the vibration transmission part has a shape that becomes thinner toward the left side of the pen, and the diameter and length of the small end face and the large end face of the vibration transmission part are determined by a resonance conditional expression. The coordinate input pen described in item 1. (3) The coordinate input pen according to claim 1 or 2, wherein the cross-sectional shape of the vibration transmitting portion in the direction of the pen tip is exponential, conical, or catenoid. (4) The coordinate input pen according to claim 1, wherein the support member is integrally molded with the vibration transmission section.