JPS60176130A - Ultrasonic wave projecting type input device - Google Patents

Abstract

PURPOSE:To measure a position coordinate of an exclusive use pen with an optimum sensitivity and less environmental noise by providing a range finding ultrasonic wave projector and a generator generating a reference signal to the inside of the exclusive use pen to allow them to transmit a modulation signal thereby measuring the distance. CONSTITUTION:The ultrasonic wave projector 21 of the exclusive use pen 1 converts a modulated electric signal transmitted from an ultrasonic wave projection controller 20 into an ultrasonic wave signal. Moreover, a lighting controller 22 generates a modulation signal being a start light signal source of ultrasonic wave projection transmitted from the lighting device 23 in synchronizing with the controller 20. A switch 24 controls a start signal of an ultrasonic wave with the method interrupting a signal transmitted from the controller 22 to the lighting device 23 through the depression at a point B of the effective coordinate face 2 and the pen 1. The coordinate of the pressing point on the effective face 2 of the pen 1 constituted in this way is obtained by measuring the time when the range finding referencing signal from the photodetector 17 and the reception signal from ultrasonic receivers 3, 4 reach a controller 9. The measurement where the sensitivity control is attained and environmental noise is not affected is attained by adopting the transmission system possible for modulation in this way.

Description

[Detailed Description of the Invention] Industrial Application Fields There are various means for inputting data to be processed and control details to be instructed to computer processing equipment used in offices, factories, etc. As a device suitable for inputting figures and handwritten characters, there is a tablet-type input device that has prescribed coordinates and can input the momentary position of a drawn figure or character on the coordinate plane to a computer processing device. A tablet-type input device usually consists of a coordinate plane, a special pen, and a control unit for detecting and transmitting coordinates. In addition, there are two types of coordinate plane plates: one is specialized by embedding conductive wires, conductive sheets, resistive sheets, etc. inside the coordinate plane, and the other is semi-specialized to define the effective coordinate plane, but in principle, there are two types of coordinate plane plates: There is a method that does not require a face plate.

In the latter case, place a transmitter and receiver for infrared light, laser light, ultrasound, etc. around the coordinate plane or inside a special pen.
This method attempts to detect the position of a dedicated pen within effective coordinates using a distance measurement method. The present invention belongs to the latter type and relates to a tablet-type input device using ultrasonic waves as a medium.

Configuration of conventional example and its problems Conventionally, as a tablet-type input device that uses ultrasound as a medium, a discharge part is provided at the internal tip of a special pen, and the ultrasonic wave emitted when the discharge part discharges is transmitted to the effective coordinate plane. An ultrasonic emission type input device has been put into practical use that detects the current coordinates of a dedicated pen by measuring the time it takes for the ultrasonic waves to reach an ultrasonic receiver placed on the outer periphery. The conventional ultrasonic emission type input device as described above will be described below with reference to the drawings.

Figure 1 is a configuration diagram of the ultrasonic emission type input device.
In the figure, 1 is a dedicated pen, and 2 is an effective coordinate plane. This device determines the position of the dedicated pen 1 within the effective coordinate plane 2,
Only when the dedicated pen 1 presses the effective coordinate plane 2 with a pressure higher than a specified value, it has the function of sending data through the terminal A to, for example, a computer processing device. The structure of the dedicated pen 1 will be explained in detail later. 3 and 4 are ultrasonic receivers, which function to capture ultrasonic waves emitted when the dedicated pen 1 discharges and convert them into electrical signals. The captured ultrasound signal is sent to amplifier 6
After being amplified by and 6, the signal is shaped into a waveform by waveform shapers 7 and 8, and then enters a controller 9. On the other hand, when electric discharge occurs inside the dedicated pen 1, electromagnetic waves are generated at the same time as ultrasonic waves are emitted. The propagation of this electromagnetic wave instantaneously enters the antenna 1o, is amplified by an amplifier 11, is waveform-shaped by a waveform shaper 12, and then enters the controller 9. This electromagnetic wave signal is a signal indicating the starting point of ultrasonic emission, and the time taken from when this signal reaches the controller 9 until the ultrasonic signal captured by the ultrasonic receiver 3 reaches the controller 9. By measuring, the distance a from the dedicated pen 1 to the ultrasonic receiver 3 can be known. In addition, the distance from the dedicated pen 1 to the ultrasonic receiver 4 can be found in the same manner.

Since the distance between the ultrasonic receivers 3 and 4 can be set to a given l, the coordinates of the effective coordinate plane 2 can be set to x- as shown in Fig. 1 using the three distances a, b, and l. Take it on the Y axis and use special pen 1
When the position coordinates of are (x, y), "+7" is calculated from the following equations.

x = (1+a - b )/(21) -- (1) y
= (a 2-x 2) 3A- (2) The conventional ultrasonic emission type input device has the above configuration and principle, but the discharge inside the dedicated pen 1 is caused by the propagation of ultrasonic waves. Taking into consideration the time and processing time of the controller 9, this is performed intermittently at a constant cycle. In addition, only when the dedicated pen 1 is pressed against the effective coordinate plane 2 with a pressure exceeding the specified value, the dedicated pen 1
The device is also designed to cause electrical discharge inside the device.

FIG. 2 is an internal configuration diagram of the dedicated pen 1, and the above functions will be explained using FIG.

In FIG. 2, 13 is a power source, and a battery or the like is used. 14 is a discharge controller, and o16 is a discharger for controlling the discharge cycle. Reference numeral 16 denotes a switch, which functions to supply power from the power source 13 to the discharger 16 and generate discharge only when the dedicated pen 1 is pressed against the effective coordinate plane 2 at point B.

In the ultrasonic emission type input device configured as described above, an electromagnetic wave signal indicating that an ultrasonic wave has been emitted in conjunction with the occurrence of an electric discharge is also used as a synchronization signal and serves as a basis for distance measurement as a distance measurement signal. Since the ultrasonic signal is also used without modulation, it is not only difficult to control the sensitivity, but also has the disadvantage of being susceptible to environmental noise.

Purpose of the Invention In view of the above-mentioned drawbacks, the purpose of the present invention is to eliminate the use of secondary generated electromagnetic waves and ultrasonic waves and adopt a modulated transmission method, thereby making sensitivity control easier and less affected by environmental noise. The present invention provides an ultrasonic projection type input device that is difficult to use.

Structure of the Invention The principle of the present invention is the same as the conventional example, but in the present invention, a light emitting device such as a laser beam or infrared light is installed as a synchronization signal generation source to notify the start of ultrasonic projection inside the dedicated pen. By placing a dedicated piezoelectric ultrasonic generator, which is a distance measurement signal generation source, in other words, an ultrasonic projector, in parallel with the light emitter, a transmission system capable of modulated transmission is created, and a dedicated pen This allows the position on the effective coordinate plane to be grasped with high reliability.

DESCRIPTION OF EMBODIMENTS FIG. 3 is a block diagram of an ultrasonic projection type input device in an embodiment of the present invention. In the detailed description of the present invention below,
Only the points different from the conventional example will be explained, and the explanation of the overlapping parts will be omitted. In FIG. 3, 17 is a light receiver. It functions to capture the ultrasonic projection start notification optical signal sent from the dedicated pen 1 and convert it into an electrical signal. This synchronized optical signal is a reference signal for distance measurement. The optical signal is amplified by an amplifier 18,
After the waveform is shaped by the waveform shaper 19, it enters the controller 9.

FIG. 4 is an internal configuration diagram of the dedicated pen 1 in the embodiment of the present invention. In FIG. 4, reference numeral 20 denotes an ultrasonic projection controller, which has a function of intermittently generating a modulation signal at a constant cycle. 21 is an ultrasonic projector, and a piezoelectric ultrasonic generator or the like is suitable. The ultrasonic projector 21 is for converting a modulated electrical signal sent from the ultrasonic projection controller 2o into an ultrasonic signal. 22 is a light emission controller, and 23 is a light emitter. The light emission controller 22 has a function of generating a modulation signal that is a starting light signal source for ultrasonic projection transmitted from the light emitter 23 in synchronization with the ultrasonic projection controller 20. 024 is a switch, and in this example, it is a dedicated pen. The ultrasonic projection start signal is controlled by a method in which the signal sent from the light emission controller 22 to the light emitter 23 is interrupted by suppression at point 1 and point B on the effective coordinate plane 2. Although the on/off control mechanism of the ultrasonic projection start signal by the switch 24 is not an essential condition of the present invention, it is added to make the operation in the embodiment of the present invention more clear.

FIG. 5 shows an example of a signal waveform of a representative part of the ultrasonic projection type input device of the present invention. The signal names and signal contents in FIG. 6 are as follows, and the locations where the signals are observed are written in FIG. 3 with the same symbols as the signal names.

In the example below, the ultrasonic receivers 3 and 4 were installed at two adjacent corners of the effective coordinate plane 2, but if the coordinates of the dedicated pen 1 within the effective coordinate plane 2 are uniquely determined. In particular, it does not matter whether it is inside or outside formed by the effective coordinate plane 2.

Effects of the Invention As described above, the present invention provides a dedicated ultrasonic projector for distance measurement and a light emitter for generating a reference signal for distance measurement inside a dedicated pen, and sends a modulated signal from them. By measuring distance, it is possible to realize a device that can measure the position coordinates of a dedicated pen four times with optimal sensitivity and with little environmental noise, and its practical effects are significant.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a conventional ultrasonic emission type input device, Fig. 2 is an internal block diagram of a dedicated pen of the conventional ultrasonic emission type input device, and Fig. 3 is an ultrasonic projection type in an embodiment of the present invention. FIG. 4 is an internal configuration diagram of the dedicated pen of the ultrasonic projection type input device in the embodiment of the present invention, and FIG. 6 is a diagram of the representative part of the ultrasonic projection type input device in the embodiment of the present invention. FIG. 1...Special pen, 2...Valid coordinate plane,
3, 4... Ultrasonic receiver, 17... Light receiver,
21... Ultrasonic projector, 23... Light emitter. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure fjIS3 Figure section 0 Lu l'-σ MiU) 綜

Claims (1)

[Claims] (1) Ultrasonic signals are transmitted from a dedicated ultrasonic projector such as a piezoelectric ultrasonic generator within the effective coordinate plane to two ultrasonic receivers installed at positions where a rectangular effective coordinate plane can be defined. , calculate the distance between the two from the propagation time of the ultrasonic wave from the ultrasonic projector to each ultrasonic receiver, and use the two distance values to calculate the input coordinate point within the effective coordinate plane of the ultrasonic projector. Ultrasonic projection type input device that indicates the position. ? ) A light emitting device is installed very close to the ultrasonic projector, and from the light emitting device to a light receiver placed near the ultrasonic receiver, a measurement signal that is the start signal of ultrasonic projection is transmitted in synchronization with the ultrasonic projection. The ultrasonic projection type input device according to claim 1, wherein a distance reference signal is sent.