JPH0512820Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application This invention relates to a drawing input device used in sketch communication devices and the like.

(b) Prior art In general, in sketch communication devices, etc., a drawing input device is superimposed on the surface of a CRT display, plasma display, or liquid crystal display, and a pen is run over the drawing input device to draw. Some devices are equipped with a drawing input device that takes in the position coordinates of , that is, drawing data, and transmit the captured drawing data through a transmission circuit.

An electromagnetic digitizer is known as this type of drawing input device. This electromagnetic digitizer is
As shown in FIG. 4, a substrate is used in which X-axis sense lines 41 and Y-axis sense lines 42 (each forming a loop coil) are arranged in a matrix on a transparent glass plate. When the surface of this board is traced and drawn with the excitation pen 43 excited by the AC signal source 44, an electromagnetic induction voltage is generated in the sense line through which the excitation pen 43 passes, and the coordinates of the trajectory of the excitation pen 43, that is, the drawing data are input. be done.

(c) Problems to be solved by the invention Since the above-mentioned conventional electromagnetic digitizer uses electromagnetic induction, it has the disadvantage that electrical coupling occurs with the display device, making it susceptible to noise.
Full-face shielding from display devices was required.

This invention was made in view of the above-mentioned disadvantages, and aims to provide a drawing input device that is not affected by noise from a display device.

(d) Means for solving the problems A configuration for solving the above problems will be explained using FIG. 1 corresponding to the embodiment.

The drawing input device of this invention has the configuration described in the following sections.

:Transparent substrate 1, :Two adjacent sides 1a of the side part of this transparent substrate 1,
Ultrasonic generator 2 provided in each of 1b
a, 2b, : the other two adjacent sides 1a of the side part of the transparent substrate 1,
Ultrasonic receiving elements 3a and 3b, which are respectively provided in the ultrasonic generators 1b and receive ultrasonic waves from the opposing ultrasonic generators 2a and 2b; A drawing pen 7, which is provided with a receiving element 8 and draws by bringing its tip into contact with the surface of the transparent substrate 1: an ultrasonic receiving element 3 provided on the transparent substrate 1;
a, 3b and the output signal of the ultrasonic receiving element 8 provided on the drawing pen 7, and the ultrasonic transmission time tx, ty from the ultrasonic generators 2a, 2b to the ultrasonic receiving element 8 and the ultrasonic generator 2.
Ultrasonic receiving element 3 facing from a and 2b
The ultrasonic transmission times tx ₀ , ty 0 to the ultrasonic wave generators 2 a, _{3 b} are counted, and the ultrasonic wave transmission times tx ₀ , ty ₀ and the ultrasonic wave receiving elements 3 a, 3 b facing the ultrasonic generators 2 a, 2 b are calculated. Reference distance between
Position of drawing pen 7 based on Dx ₀ and Dy ₀
Calculating means 9 for calculating Dx and Dy.

(E) Function In the drawing input device of this invention, when drawing with the drawing pen 7, ultrasonic waves are periodically emitted from the ultrasonic generators 2a and 2b. Transmission time of this ultrasound
From tx, ty, tx ₀ , ty ₀ and reference distance Dx ₀ , Dy ₀ ,
The coordinates Dx and Dy of the drawing pen 7 are calculated from the following formula.

Dx＝Dx ₀ tx／tx ₀ , Dy＝Dy ₀ ty／ty _0The change in ultrasonic transmission speed due to temperature is the transmission time
It is canceled by taking the ratio of tx, ty and tx ₀ , ty ₀ , and Dx, Dy have values that have been position-corrected for temperature changes.

In this manner, the drawing input device of this invention uses ultrasonic waves to input drawings, and therefore noise from the display device can be avoided.

(F) Embodiment An embodiment of this invention will be described below based on FIGS. 1 to 3.

FIG. 2 is an external perspective view of a drawing input device according to an embodiment of this invention.

1 is a rectangular transparent substrate made of glass or the like. On the sides 1a and 1b of this transparent substrate 1,
Band-shaped ultrasonic transducers (ultrasonic generators) 2a, 2b
is provided. The ultrasonic transducer 2a is in close contact with the entire surface of the side 1a via the matching layer 4 (see FIG. 3). This matching layer 4 is for transmitting the ultrasonic energy generated by the ultrasonic transducer 2b to the transparent substrate 1 with as little loss as possible. Further, a backing layer 5 is provided on the back surface of the ultrasonic transducer 2a. This backing layer 5 is for reflecting forward the backward radiation component of the ultrasonic waves generated by the ultrasonic transducer 2a. The ultrasonic transducer 2b is also provided on the side 1b with a completely similar mounting structure.

Ultrasonic transducers (ultrasonic receiving elements) 3a and 3b are also provided on the other sides 1a and 1b of the transparent substrate 1, respectively. These ultrasonic transducers 3a, 3b
are opposite to the ultrasonic transducers 2a and 2b, respectively, have the same structure as the ultrasonic transducers 2a and 2b, and are in close contact with the sides 1a and 1b. That is, to explain the ultrasonic transducer 3a, the ultrasonic transducer 3a
is in close contact with the side 1a via a matching layer 4, and a backing layer 5 is provided behind it (see FIG. 3).

A matching layer 6 is also provided on the surface 1d of the transparent substrate 1. Through this matching layer 6,
The tip of the drawing pen 7 contacts the surface 1d of the transparent substrate 1.
An ultrasonic sensor (ultrasonic receiving element) 8 is provided at the tip of the drawing pen 7 and detects ultrasonic waves propagating within the transparent substrate 1. The matching layer 6 includes:
This is for transmitting ultrasonic energy from the transparent substrate 1 to the ultrasonic sensor 8 without loss.

FIG. 1 shows a circuit block diagram of the drawing input device.

The ultrasonic transducers 2a, 2b, 3a, 3b and the ultrasonic sensor 8 are all connected to an arithmetic circuit 9. Voltages are alternately and periodically applied to the ultrasonic transducers 2a and 2b by pulse signals Pua and Pub from the arithmetic circuit 9, respectively. Received signals Pra of the ultrasonic transducers 3a, 3b and the ultrasonic sensor 8,
Prb and Pr ₈ are each input to the arithmetic circuit 9.
This arithmetic circuit 9 uses an ultrasonic transducer 2a (or 2b)
The time from when a pulse signal is emitted to when a signal is received by the ultrasonic sensor 8 and the ultrasonic transducer 3a (or 3b), that is, the transmission time, is counted, and the tip of the drawing pen 7 is calculated based on this transmission time. Detect location.

When inputting drawing data using the drawing input device of this embodiment, hold the drawing pen 7 in your hand and move the ultrasonic sensor 8 at the tip in contact with the transparent substrate surface 1d to draw a desired trajectory. let While the drawing pen 7 is moving, the arithmetic circuit 9 applies pulse signals Pua and Pub to the ultrasonic transducers 2a and 2b alternately at predetermined intervals, respectively.

In the following explanation, assuming that the pulse signal Pua is given to the ultrasonic transducer 2a, the ultrasonic transducer 2
A is applied with voltage by this pulse signal Pua, and generates ultrasonic waves. This ultrasonic wave propagates in the x-axis positive direction in the transparent substrate 1 as a plane wave (first
(see figure).

This ultrasonic wave is detected by the ultrasonic sensor 8 when it passes through the contact point C at the tip of the drawing pen 7.
At this time, the received signal Pr ₈ from the ultrasonic sensor 8 is input to the arithmetic circuit 9. The arithmetic circuit 9 counts the time from when the pulse signal Pua is generated until the received signal Pr ₈ is input, that is, the propagation time tx.

Further, the ultrasound waves reach the ultrasound transducer 3a. At this time, the received signal from the ultrasonic transducer 3a
Pra is input to the arithmetic circuit 9. The arithmetic circuit 9 is
The time from the time when the pulse signal Pua is generated until the received signal Pra is input, that is, the transmission time tx ₀ is counted.

Furthermore, the arithmetic circuit 9 calculates the ratio between time tx and tx ₀ and calculates the ratio (tx/tx ₀ ) and the reference distance in the X-axis direction of the transparent substrate 1 (the distance between the ultrasonic transducers 2a and 3a).
Take the product with Dx ₀ , and take the product of the X coordinate of contact point C Dx (=
Calculate Dx ₀・tx/tx ₀ ).

In this way, based on the distance Dx ₀ , the X coordinate
By calculating Dx, it is possible to correct deviations due to changes in the ultrasonic transmission speed within the transparent substrate 1 due to temperature. If the transmission time is constant and the X coordinate Dx is calculated only from time tx ₀ , a position error will occur due to temperature change. So time tx
By taking the ratio of and tx ₀ , changes in the transmission speed due to temperature are canceled, and by multiplying this by the reference distance Dx ₀ , the X coordinate is corrected for the temperature change.
Dx will be obtained.

Next, the arithmetic circuit 9 emits a pulse signal Pub to the ultrasonic transducer 2b, and receives the received signal from the ultrasonic sensor 8.
Transmission time ty until Pr ₈ and ultrasonic transducer 3
Count the transmission time ty ₀ until the received signal of b is received. These transmission times ty, ty ₀ and the reference distance in the Y-axis direction of the transparent substrate 1 (distance between the ultrasonic transducers 2b and 3b)
From Dy ₀ , as before, Y coordinate Dy of contact point C (=
Dy ₀・ty/ty ₀ ) is calculated.

As mentioned above, the X coordinate Dx and the Y coordinate Dy
is calculated, and the trajectory of the tip of the drawing pen 7 is input. The arithmetic circuit 9 outputs drawing data consisting of these coordinates Dx and Dy to a transmission circuit (not shown) or the like.

(g) Effects of the invention As explained above, the drawing input device of this invention uses ultrasonic waves to input the coordinates of the trajectory of the drawing pen, so there is no electrical coupling with the display device. , it has the advantage of not being affected by noise from the display device. In addition, in order to detect pen contact, an ultrasonic receiving element is installed inside the tip of the drawing pen.
When the drawing pen comes into contact with the transparent substrate, the ultrasonic wave propagating inside the transparent substrate is detected by the ultrasonic receiving element of the drawing pen, so it will not work unless the drawing pen comes into contact with the substrate, and other causes may occur. For example, errors such as position detection caused by a person touching their hand or placing an object will not occur.

Further, there is an advantage that the influence of changes in the ultrasonic transmission speed of the transparent substrate due to temperature is eliminated, and drawing data can be accurately input.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of a circuit of a drawing input device according to an embodiment of the invention, FIG. 2 is an external perspective view of a transparent substrate and a drawing pen of the same drawing input device, and FIG. , FIG. 4 is a vertical cross-sectional view showing the same transparent substrate with a part omitted, and is a diagram illustrating a conventional electromagnetic digitizer. 1...Transparent substrate, 2a, 2b, 3a, 3b...
Ultrasonic transducer, 7... Drawing pen, 8... Ultrasonic sensor, 9... Arithmetic circuit, tx, ty, tx ₀ , ty ₀ ... Transmission time, Dx ₀ , Dy ₀ ... Reference distance.

Claims (1)

[Claims for Utility Model Registration] A transparent substrate, ultrasonic generators provided on two adjacent sides of the transparent substrate, and ultrasonic generators provided on two adjacent sides of the transparent substrate, respectively. an ultrasonic receiving element that receives ultrasonic waves from the ultrasonic generators that are provided and facing each other; and an ultrasonic receiving element that receives ultrasonic waves from the ultrasonic generators at a tip thereof, the tip of which is provided on the surface of the transparent substrate. a drawing pen that draws by contacting the drawing pen; The ultrasonic transmission time to the ultrasonic receiving element and the ultrasonic transmission time from the ultrasonic generator to the opposite ultrasonic receiving element are counted, and the transmission time and the ultrasonic wave transmission time between the ultrasonic generator and the opposite ultrasonic wave are counted. A drawing input device comprising calculation means for determining the position of the drawing pen based on a reference distance between the drawing pen and a sound wave receiving element.