JPH045718A - Input device - Google Patents

Abstract

PURPOSE:To obtain position information independent of a propagating state by receiving an ultrasonic wave generated form an ultrasonic wave generator located at the peripheral part of a display device by a pen with a built-in ultrasonic wave detector, and counting it by a counter, and executing arithmetic operation by a computing element. CONSTITUTION:The ultrasonic wave generated at time t1 from the ultrasonic wave generator 2 located at the peripheral part of the display device 1 propagates on the surface of the device 1, and is detected at the time t3 by the ultrasonic wave detector 3 installed at the opposite side of the device 1, and a time interval k1=t3-t1 is counted by the counter 9. When an inputting operator touches the surface of the device 1 by the tip of the pen 4 with the built-in ultrasonic wave detector 5 at the time t2 between the time t1 and the time t3, the time interval k2= t2-t1 is counted by the counter 9. By calculating a relative position to the full scale of a display screen by dividing the interval k2 by the interval k1 by the computing element 7, the position information on the surface of the device 1 is obtained. Thus, the change of the propagating speed of the ultrasonic wave due to a reason such as temperature, pressure, and the deformation of the surface of the device 1, etc., is canceled, and always the correct position information can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an input device used in a personal computer or the like.

[Prior Art] Conventionally, as a method for detecting the position pointed by an input user using an input device used in a personal computer, etc., ultrasonic waves from an ultrasonic generator installed in an input pen are applied to the surface of a display device. A known method is to detect an ultrasonic wave using an installed ultrasonic detector, measure the time from the generation of the ultrasonic wave to the detector, and convert this into position information.

[Problems to be Solved by the Invention] However, in the conventional technology, the propagation state of ultrasonic waves on the surface of the display device changes due to changes in temperature, shape, etc., so the reliability of the converted position information becomes low and the accuracy of position specification becomes difficult. The problem is that it cannot be improved.

SUMMARY OF THE INVENTION The present invention is intended to solve these problems, and its purpose is to provide an input device that detects positional information with high reliability and high resolution.

[Means for Solving the Problems] In order to solve the above problems, an input device of the present invention is characterized in that it includes an ultrasonic generator, an ultrasonic detector, a counter, and an arithmetic circuit. Examples] Examples of the present invention will be described below based on the drawings.

In FIG. 1, ultrasonic waves generated at time t1 from an ultrasonic generator 2 located at the periphery of a display device 1 are transmitted across the surface of the display device to an ultrasonic detector 3 provided at the opposite end of the display device. Detected at time t3, counter 9 detects time interval k
l=t3-tl is counted.

When the user touches the surface of the display device 10 with the tip of the pen 4 containing the ultrasonic detector 5 at time t2 between times t1 and t3, the counter 9 counts 2=t2-tl in the time interval.

Conventionally, the distance from the point of contact of the pen to the display device to the ultrasonic generator was calculated by dividing the time interval by 2 by the known propagation velocity v1 of the ultrasonic wave using a calculator. The accuracy was low because the propagation velocity v1 changed due to factors such as temperature, pressure, and deformation of the surface of the display device.

In the present invention, position information on the surface of the display device is obtained by calculating the relative position of the display surface with respect to the full scale by dividing the time interval by 2 by 1 in the arithmetic unit 7. In this way, changes in the propagation speed of ultrasonic waves due to temperature, pressure, deformation of the surface of the display device, etc. are canceled, so that accurate position information can always be obtained.

If one set of an ultrasonic generator and an ultrasonic detector are provided in two directions, horizontal and vertical, of the display device, the horizontal and vertical positions on the display device can be determined separately.

A similar effect can be achieved by incorporating the ultrasonic generator 8 in the input pen 4 and installing the ultrasonic detectors 6a and 6b oppositely on both ends of the display section of the display device, as shown in FIG.

In this case, the time at which the ultrasonic wave generated from the ultrasonic generator 8 at time t1 is transmitted through the surface of the display device and detected by the ultrasonic detectors 6a and 6b provided in the display device is t.
2. Assuming t3, in the arithmetic unit 7, (t 2-
By calculating t1)/(t2+t3-2*t1), it is possible to obtain correct positional information that cancels changes in the propagation velocity of the ultrasonic waves due to deformation of the surface of the display device or the like.

If one set of ultrasonic detectors is provided in each of the two directions, horizontal and vertical, of the display device, the horizontal and vertical positions on the display device 1 can be determined separately.

[Effects of the Invention] As explained above, the present invention has the effect that highly accurate positional information can be input regardless of changes in the propagation state of ultrasonic waves on the surface of the display device.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a first embodiment of an input device according to the present invention. FIG. 2 is a block diagram of a second embodiment of the input device according to the present invention. 1, display device 2, ultrasonic generator 3, ultrasonic detector 4, pen 5, ultrasonic detector 6a, ultrasonic detector 6b, ultrasonic detector 7, calculator 8, ultrasonic generator 9, counter Applicant Seiko Epson Co., Ltd. Attorney Kizobu Tsuchi Suzuki (and 1 other person)

Claims (1)

[Claims] An input device used in a computer or the like, comprising an ultrasonic generator, an ultrasonic detector, a counter, and an arithmetic circuit.