JPH07200143A - Position detection device for moving body - Google Patents

Abstract

PURPOSE:To detect the movement position of the moving body such as an input pen by an optical means without connecting any cable to the moving body. CONSTITUTION:An irradiation body 5 outputs amplitude-modulated infrared light, which is reflected by the tip part 1a of the pen and detected by photodetection bodies 6a and 6b. A phase difference is found from the output intensity that the photodetection parts 6a and 6b photodetect and the modulation intensity of the output light from the irradiation body 5. The phase difference obtained from the photodetection outputs of the two photodetection bodies 6a and 6b includes component (L0+L1) and (L0+L2) of a distance. The absolute position of the tip part 1a of the pen 1 can be found from information based upon the phase difference and the installation distance L between the irradiation body and photodetection bodies. The pen 1 only needs to have a reflecting function and the need to connect a cable to the pen is eliminated, so input operation is facilitated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention outputs light to a moving body, receives reflected light from the moving body, and detects the position of the moving body based on, for example, a phase difference in light intensity between the output light and the reflected light. The present invention relates to a position detecting device for a moving body that calculates

[0002]

2. Description of the Related Art A mouse, a light pen, a tablet type pen input device in a computer, etc. are known as an example of a conventional position detecting device for a moving body. In these input devices, the amount of movement of a mouse or a light pen as a moving body is converted into the amount of movement of a display point (cursor or the like) on a display, and a figure or the like is input by the locus.

[0003]

However, as described above, in the mouse, light pen, or tablet type pen input device, in order to transmit the position information of the mouse or the like, the moving object such as the mouse is extended from the computer. You have to connect the specified cable. For this reason, there is a problem that this cable interferes with the operation of handwriting input.

It is an object of the present invention to provide a position detecting device for a moving body which can detect the position of the moving body by optical means without providing a cable or the like on the moving body.

[0005]

According to another aspect of the present invention, there is provided a position detecting device for a moving body, a moving body having a light reflecting portion, an illuminating body for outputting intensity-modulated light toward a moving area of the moving body, It is characterized by having a plurality of light receiving bodies for receiving the light reflected from the moving body, and means for calculating the position of the moving body based on the light reception output from each of the light receiving bodies.

In the above, it is possible to calculate the position of the moving body from the phase difference between the intensity modulation signal of the output light from the irradiation body and the light reception output signal of each light receiving body.

[0007]

In the above means, the moving body having the light reflecting function is used as a position inputting means for a computer, for example. When the output light from the illuminating body reaches the moving body, it is reflected by the moving body, and the reflected light is received by the plurality of light receiving bodies. The position of the moving body can be calculated from the received light output from the light receiving body.

As an example of the calculation of the position of the moving body, the phase difference between the intensity modulation signal of the light emitted from the illuminating body and the light receiving output signal of the light receiving body is obtained, and from this phase difference, the illuminating body passes through the moving body. It is possible to obtain the optical path length to each light receiving body and obtain the absolute position of the moving body from a plurality of optical path lengths.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an embodiment in which the position detecting device for a moving body of the present invention is applied to a pen type input device of a computer,
2 is a block diagram showing the configuration of the input device of FIG. 1, and FIG. 3 is an explanatory diagram for explaining the principle of detecting the position of a moving body.
(A) is a plan view showing the positional relationship of each member, (B) is a diagram showing the relationship between the phase difference between the output light and the reflected light. Figure 1
Reference numeral 1 indicates a pen as a moving body. A tip portion 1a of the pen 1 is formed into a mirror-polished spherical shape so that light can be reflected by the tip portion 1a.

Reference numeral 2 is an input section, which is a display 13
Is installed in front of the computer main body 7 having. The input unit 2 is composed of an optical unit 3 and a pointing board 4. An illuminator 5 is arranged at the center of the optical section 3, and the illuminator 5 outputs infrared light whose light intensity is modulated. This output light has no directivity and is emitted toward the pointing board 4 with a predetermined diffusion angle. At both ends of the optical section 3, there are light receivers 6a, 6
b is arranged, and the reflected light reflected by the tip portion 1a of the pen 1 is received by the light receivers 6a and 6b. In this input device, the input range (moving range) of the pen 1 needs to be within the output light irradiation area A. Therefore, it is preferable that the pointing board 4 and the optical section 3 are separated by a certain distance. In the example of FIG. 1, the indicator board 4 and the optical unit 3 are connected with a distance provided by the connection sheet 4a. However, the indicator board 4 may be a separate body from the optical unit 3, or when the optical unit 3 is installed on a flat table surface, the indicator board 4 need not be provided and the pen 1 may be attached to the table surface. It can also be moved along.

As shown in FIG. 2, in this input device, an illumination control section 8 for modulating and controlling the emission intensity of the illuminating body 5 and a light receiving detecting section 9 for detecting light receiving outputs from the light receiving bodies 6a and 6b.
And a phase difference detection unit 10 for detecting the phase difference between the modulation intensity of the output light and the intensity of the received light output. Further, there is provided a calculator 11 that calculates the position of the tip 1a of the pen 1 from the detection result of the phase difference detector 10. Of the circuit units shown in FIG. 2, for example, the illumination control unit 8, the light reception detection unit 9, and the phase difference detection unit 10 are built in the optical unit 3. The computing unit 11 is a CPU in the computer main body 7.
And the calculation is executed by software.

Next, the operation of the input device will be described. The illuminator 5 is an infrared light emitting diode or the like. The illumination control unit 8 forms a modulation signal with a predetermined frequency "f0", and the light intensity of the output light from the illumination body 5 changes based on the modulation signal. The infrared light that is modulated and output is emitted toward the pointing board 4, and the tip portion 1 a of the pen 1 is irradiated.
And the reflected light is received by each of the light receivers 6a and 6b. The light receivers 6a and 6b are photoelectric converters such as photodiodes, and a current proportional to the intensity of the received light is obtained. In the light reception detection unit 9, the current is converted into a voltage, and the voltage is given to the phase difference detection unit 10.
The modulation signal given to the illuminating body 5 is given from the illuminating control section 8 to the phase difference detecting section 10 as a voltage, and in the phase difference detecting section 10, the light received by each of the light receiving elements 6a, 6b is compared by comparing the two voltages. The phase difference between the intensity and the modulation intensity of the output light from the illuminator 5 is obtained. The signal based on this phase difference is digitally converted and given to the arithmetic unit 11 so that the pen 1
The absolute position of the tip portion 1a of is calculated.

In FIG. 3A, the distance from the center of the illuminating body 5 to the centers of both the light receiving bodies 6a and 6b is L, and the linear distance from the illuminating body 5 to the tip portion 1a of the pen 1 at a certain point. L
0, the straight line distance from the tip 1a of the pen 1 to each of the light receivers 6a and 6b is represented by L1 and L2. FIG. 3B shows a change in the light intensity in the optical path length (L0 + L1) until the infrared light output from the illuminator 5 is reflected by the tip 1a of the pen 1 and received by the light receiver 6a. There is. The light intensity of the infrared light output from the illuminator 5 has a predetermined frequency “f
However, in FIG. 3B, the intensity of the infrared light emitted from the illuminator 5 is at the midpoint of the intensity amplitude.

The phase difference between the light intensity of the infrared light received by the light receiver 6a and the intensity of the output light from the illuminator 5 is represented by "φ".
1 "and the speed of light is" c ",

[Expression 1] φ1 = 2π · (L0 + L1) · f0 / c

The phase difference φ2 between the light intensity of the infrared light received by the light receiver 6b and the intensity of the output light from the illuminator 5 is:

[Expression 2] φ2 = 2π · (L0 + L2) · f0 / c

The dimension of each phase difference φ1 and φ2 is "radian".
Is. As described above, the phase difference detection unit 10 obtains the difference between the light reception output voltage of each of the light receivers 6a and 6b obtained from the light reception detection unit 9 and the light intensity modulation voltage of the illumination control unit 8. However, the phase differences φ1 and φ2 are detected from this voltage difference and the amplitude of the light intensity modulation voltage. A signal based on the phase difference φ1 and φ2 is digitally converted and given to the arithmetic unit 11.

An example of arithmetic processing in the arithmetic unit 11 will be described. When the phase difference φ1 at a certain point is obtained, the illuminator 5
The optical path length from the pen to the light receiving body 6a via the tip 1a of the pen 1 is (L0 + L1). The tip portion 1a of the pen 1 when this optical path length is obtained is located on an elliptical locus P1 whose focal points are the center of the illuminating body 5 and the center of the light receiving body 6a. Therefore, based on the information of the phase difference φ1, the illuminator 5 and the photodetector 6a are
The equation of the elliptical locus P1 having the focus at the position of can be obtained. Similarly, when the information of the phase difference φ2 is obtained, the tip 1a of the pen 1 is located on the elliptical locus P2 whose focal points are the positions of the illuminator 5 and the photodetector 6b. Therefore, the equation of the elliptical locus P2 can be obtained from the information of the phase difference φ2. If the intersection of the elliptical loci P1 and P2 is obtained from both equations, it will be the coordinate position of the tip 1a of the pen 1 at a certain point.

As another calculation method, the phase difference φ1
Since the information (L0 + L1) is obtained from the information (1) and the distance L between the illuminator 5 and the light receiver 6a is determined, (L + L0 + L1) can be obtained. As a result, a triangle having the illuminator 5, the light receiver 6a, and the tip 1a of the pen 1 as its vertex is determined. Similarly, (L + L0 + L2) is obtained from the information of the phase difference φ2 and the distance L, and a triangle having the illuminator 5, the light receiver 6b, and the tip 1a of the pen 1 as its apex is obtained. A triangle with a predetermined value of (L + L0 + L1),
Among triangles having a predetermined value of (L + L0 + L2), the position of the tip portion 1a of the pen 1 can be calculated by determining a triangle having common vertices.

Next, FIG. 4 shows another embodiment of the present invention. In this embodiment, optical members 14a and 14b having light emitting and light receiving functions are arranged at two positions with a distance of 2L. The light emitted from one optical member 14a is reflected by the tip 1a of the pen 1 and the same optical member 1a.
The light is received by 4a, and the phase difference between the received light output and the emitted light output is detected. Thereby, the distance L1 can be obtained. Similarly, the light emitted from the optical member 14b is reflected by the tip 1a of the pen 1 and received by the optical member 14b, and the distance L2 is obtained from the phase difference at this time. The absolute position of the tip 1a of the pen 1 can be calculated from the distance L1, the distance L2, and the distance L. In this case, the output light from the optical member 14a and the optical member 14b
It is necessary that the output light from the optical components does not interfere with each other. For that purpose, it is necessary to shift the phase of the intensity modulation of the output light from both optical members 14a and 14b, or to change the wavelength. .

[0020]

According to the present invention, it is sufficient for the moving body to have a reflecting function, and it is not necessary to connect a cable to the moving body. Therefore, the moving operation of the moving body becomes easy. In addition, coordinates can be input by moving the moving body.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment in which a position detecting device for a moving body of the present invention is applied as a pen-type input device for a computer;

FIG. 2 is a block diagram showing the configuration of the pen-type manual input device shown in FIG.

3A and 3B are explanatory views of a position detection operation of a moving body (pen), (A) is a plan view showing the arrangement of each member, and (B) is a line showing the relationship between the optical path length of output light and the light intensity. Figure,

FIG. 4 is a plan view showing another embodiment of the pen-type input device,

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pen 1a Tip part 2 Input part 3 Optical part 4 Indicator board 5 Illuminator 6a, 6b Photoreceptor 7 Computer main body 8 Illumination control part 9 Light reception detection part 10 Phase difference detection part 11 Computing part 13 Display 14a, 14b Optical member

Claims (2)

[Claims] 1. A moving body having a light reflecting portion, an illuminating body that outputs intensity-modulated light toward a moving region of the moving body, and a plurality of light receiving bodies that receive the light reflected from the moving body. , A means for calculating the position of the moving body based on the light reception output from each of the light receiving bodies. 2. An intensity-modulated signal of output light from the illuminating body,
2. The position detecting device for a moving body according to claim 1, further comprising means for calculating the position of the moving body from the phase difference between the light receiving output signal of each light receiving body.