JP2865754B2 - Optical two-dimensional coordinate input device and coordinate input pen - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-dimensional coordinate input device, a digitizer, and a coordinate input device for inputting a figure or the like by specifying two-dimensional coordinates.

2. Description of the Related Art Conventionally, various types of coordinate input devices for designating two-dimensional coordinates, such as a magnetostrictive system, an electromagnetic induction system, a pressure-sensitive system, and an electrostatic induction system, are known. Each of the conventional coordinate input devices basically has a coordinate designating unit composed of a tablet that defines a two-dimensional coordinate plane or a combination of an input board and an input device movable on the tablet. The tablet and the input device are connected by electrical, magnetic or mechanical signals, and the transmission of these signals detects the position of the input device on the two-dimensional coordinate plane, and specifies the input coordinates.

[Problems to be Solved by the Invention] However, in the above-described conventional coordinate input device, the input panel requires a special structure according to the type of physical quantity to be used in order to be able to exchange signals with the input device. It is a so-called dedicated tablet, which has a predetermined dimensional shape structure. Therefore, the plane area of the coordinates input by the conventional device was necessarily limited by the area of the tablet. For this reason, it has not been possible to freely input figures and the like existing in an arbitrary wide and narrow plane area.

SUMMARY OF THE INVENTION In view of the problems of the conventional two-dimensional coordinate input device, it is a first object of the present invention to provide an optical coordinate input device applicable to a two-dimensional coordinate plane having an arbitrary area.

In the above-described conventional two-dimensional coordinate input device, the input device is always used in combination with a dedicated tablet capable of transmitting and receiving signals, and cannot be applied to an arbitrary two-dimensional coordinate plane apart from the tablet. Also, the plane size of the dedicated tablet is physically limited, and the input device cannot freely input a wide range of two-dimensional information.

In view of the above-mentioned problems of the conventional input device, the present invention provides an input device which can be applied to any two-dimensional coordinate plane freely in principle without restriction from the tablet, and has substantially no restriction on the coordinate input designation range. The second purpose is to provide.

[Means for Solving the Problems] In order to achieve the first and second objects, according to the present invention, a two-dimensional coordinate input device is directed toward a retroreflective input device arranged on an arbitrary coordinate plane. Then, a laser beam is incident from a pair of light sources installed separately from each other, and coordinate input is performed based on the principle of triangulation using the retroreflection. First
FIG. 1 is a diagram showing a configuration of an optical two-dimensional coordinate input device according to the present invention. This device has a retroreflective input device 1.
In order to specify coordinates to be input, the input device 1 is operated so as to be movable in a finite area along an XY coordinate plane 2 having given dimensions. Input device 1 is the central axis P ₀ is aligned at a predetermined point in order to specify the predetermined coordinates. An incident light beam that is angularly scanned so as to cross the central axis of the input device 1 is reflected by the cylindrical retroreflective surface of the input device 1, and the reflected light beam recursively reverses.

The light source unit 3 is mounted on the upper edge of the coordinate plane 2.
The light source unit 3 has a pair of light source units 4 and 5. The right light source unit 4 emits incident light while scanning angularly along the coordinate plane 2 from the specific point P _1, and receives a reflected light that is retroreflected by the input device 1 and travels backward to generate a detection pulse. I do. This detection pulse has a pulse width corresponding to the time when the incident light beam crosses the cylindrical retroreflective surface of the input device 1, and coincides with the time when the center position of the pulse width passes through the central axis P ₀ of the input device 1. I have. The light source unit 5 of the left, the other specific points apart from the specific point P ₁ by a distance L in the reference line
An incident light ray is generated while scanning angularly along the coordinate plane ₂ from P2. The incident light beam is similarly retroreflected by the input device 1, and the reflected light beam traveling backward is received by the left light source unit 5 and a similar detection pulse is output.

Further, the present coordinate input device includes a pair of light source units 4 and 5
And a calculation unit 6 connected to the The calculation unit 6 is constituted by a computer or the like, and electrically processes a detection pulse generated in the right light source unit 4 to form a declination between an optical path connecting the specific point P ₁ and the central axis P ₀ of the input device 1 to a reference line. determine a theta _1, determines the deflection angle theta ₂ formed between the optical path and the reference line detection pulse generated at the left light source unit 5 electrically processing connecting the center axis P ₀ of the input unit 1 and the specific point P ₂ Circuit means. Further, using these determined angle values θ ₁ and θ ₂ and the set point-to-point distance L, calculating means for calculating coordinates specified by the input device 1 (that is, coordinates of the central axis P ₀ ) according to the principle of triangulation. Having. The calculation result is displayed on a display 7 such as a CRT included in the calculation unit 6.

A pen-type input device is used as the input device 1. This pen-type input device is composed of a writing implement-shaped gripping member having a central axis and a cylindrical surface along the central axis, and a retroreflective layer arranged on the cylindrical surface to reflect incident light rays recursively. By holding the gripping member and moving the coordinate axis on the coordinate plane while keeping the central axis substantially perpendicular to the given coordinate plane, the center axis is aligned with a specific point on the coordinate plane and coordinate input is performed.

[Operation] of the central axis P ₀ of the input device 1 in the case shown in Figure 1 the coordinates (x, y) is calculated according to the following equation.

According to the present invention, since the center axis coordinate of the input device is determined by the principle of triangulation using a laser beam, a tablet or input panel having any special structure is not required. By using a pen as the input device, coordinate input can be performed with extremely high workability.

[Embodiment] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 2 is a diagram showing a coordinate input pen used in the coordinate input device according to the present invention. As shown in the drawing, the optical coordinate input pen 1 includes a gripping member 10 having a central axis and a writing tool shape having a cylindrical surface along the central axis. A retroreflective layer 11 for recursively reflecting an incident light beam is disposed on a cylindrical surface near the tip of the grasping member 10. Further, a shaft member 12 that can move in the direction of the central axis is inserted into a distal end portion of the holding member 10. Coordinate designation is performed by manually operating the grasping member 10 and adjusting the shaft member 12 to a desired coordinate point, and instructing execution of coordinate input by pressing the shaft member 12 against a coordinate plane. That is, the shaft member 12 has a coordinate input switch function in addition to a coordinate designation function. A light emitting unit 13 that optically emits a switch input signal in accordance with the movement of the shaft member 12 is provided at the top of the holding member 10. This input pen is more excellent in workability and operability than a cursor-type input device, and is particularly useful when performing coordinate input using a ruler or performing point input.

The retroreflective layer 11 has a function of recursively reflecting an incident light beam and traveling backward to direct the incident light beam to a light source. A pair of point light sources separated from each other by a distance L as shown in FIG.
Laser beam two from P ₁ and P ₂ are assumed to be emitted. The laser beam emitted from the point light source P ₁ is the input pen 1
Are scanned at a constant angular velocity counterclockwise along the XY coordinate plane where During scanning, the laser beam crosses the cylindrical surface of the input pen in the circumferential direction, and the retroreflective layer on the cylindrical surface
The light is recursively reflected backward by 11 and follows the same optical path as the incident optical path, returns to the point light source, and is received and detected. Similarly, is recursively reflected by the retroreflective layer 11 is angularly scanned in a clockwise direction along the laser beam even X-Y coordinate plane which is emitted from the light source P ₂ otherwise.

Now, in order to obtain the two-dimensional coordinates of the specified coordinate point P ₀ based on the triangulation method, the declination θ ₁ where the optical path connecting the specified point P ₀ and the light source ₁ forms the reference line L, and the specified point P ₀ It is necessary to determine the declination θ ₂ between the optical path connecting the other light sources P ₂ and the reference line L.
3 is a graph showing the distribution of the retroreflected laser beam intensities received and detected at the position of the point light source P _1. The declination or scanning angle of the incident laser beam is taken on the horizontal axis,
The intensity of the reflected laser beam starts to increase after the laser beam starts to cross the retroreflective layer 11, and decreases when the laser beam finishes to cross the retroreflective layer 11 on the cylindrical surface of the input pen 1. Meanwhile, the reflected laser beam intensity is at a substantially constant level. Therefore, it cannot be determined directly from this flat intensity distribution when the incident laser beam has passed the central axis of the input pen. Therefore,
As will be described later, the deflection angle is determined by electrically processing a detection pulse corresponding to the reflected laser beam light intensity distribution.

Since the retroreflective layer 11 has a function of reflecting at least a part of the incident light rays directionally and following the same optical path and moving backward, regardless of the fluctuation of the incident angle, even if the gripping member 10 has Alternatively, even if the central axis is tilted due to unevenness of the coordinate plane 2 and the incident angle of the laser beam on the retroreflective layer 11 is changed, the retroreflective laser beam always points to the light source. Note that the retroreflection efficiency of the retroreflection layer 11 generally depends on the incident angle, and it is sufficient if at least a part of the light quantity is recursively reflected.

FIG. 4 is a partially enlarged sectional view of the retroreflective layer 11 shown in FIG. The retroreflective layer 11 is composed of an aggregate of retroreflective elements each having an optical retroreflective effect. In this embodiment, the aggregate of the recursive elements is composed of a myriad of photorefractive microspheres 111 arranged at high density. The microspheres 111 are made of, for example, glass beads having a particle size of several tens of microns and a refractive index of 2.20 to 2.22. In this embodiment, the retroreflective layer 11 has a multilayer structure and a microsphere 111.
A transparent resin surface layer 112 for dispersing and supporting
And an adhesive layer 113 formed on the back surface of the substrate.
For the sake of illustration, the light rays 114 incident on the individual microspheres 111 undergo strong refraction and are converged on the rear spherical surface of the sphere. After being reflected and refracted again, it is emitted as a parallel ray 115. The outgoing ray 115 therefore has a strong directivity and travels back to the source of the incoming ray 114.

FIG. 5 shows a cross-sectional structure of the input pen 1. A gripping member 10 made of synthetic resin is axially slidably received from a position-designating shaft member 12 at a tip thereof, and a switch is provided at a rear portion thereof.
14 are provided. A drive circuit 15 and a secondary battery 16 are accommodated in the vicinity of substantially the center of the gripping member 10, and an infrared ray passing window 17 is provided along the circumferential direction at the rear end, and further an infrared light emitting diode 18 is accommodated. ing. When the input pen is placed at a position to be input on the coordinate plane and the tip of the shaft member 12 is pressed against the coordinate plane, the switch 14 is turned on, the drive circuit 15 is activated, and the switch signal is turned on by the diode. 18
Sent to The diode 18 converts the switch signal into an infrared ray and emits the infrared ray.The infrared ray is radiated to the outside through the reflector 19 and the infrared ray passing window 17 on which the peripheral surface of the substantially hemispherical member is chrome-plated. .

FIG. 6 is a circuit diagram showing the electrical structure of the input pen. In the figure, a drive circuit 15 receives power supply from a secondary battery 16 and when a switch 14 is turned on, a light emitting diode
A switch signal having a specific waveform is sent to 18. The diode 18 converts this into an infrared signal and emits it. The infrared light is reflected by the convex mirror 19 and emitted to the outside through the infrared ray passing window 17.

FIG. 7 is a diagram showing an optical configuration of the light source unit 4 shown in FIG. The optical configuration of the other light source unit 5 is the same, and the only difference is that the geometrical arrangement of each optical component is symmetrical to that of the light source unit 4, so that the detailed description is omitted.

A laser light source 40 for the light source unit 4 is generated along the reference line incident light, at a constant angular velocity around a specific point P ₁ to scan along the coordinate plane given incident light to angularly It has a rotating reflecting mirror 41 that rotates, and a light receiving element 42 for receiving the reflected light reflected back by the input pen and generating a detection pulse. As is clear from the figure, the laser light source 40
Incident on the rotary mirror 41 passes through the half mirror 43 toward the center of rotation of the rotary reflecting mirror 41. Here, the incident light beam is scanned at a constant angular velocity, retroreflected by the input pen, travels backward, returns to the rotary reflecting mirror 41, and is reflected there to be reflected by the half mirror 43.
Proceed to. The reflected light beam is separated from the incident light beam by the half mirror 43 and received by the light receiving element 42 composed of a photodiode or the like via a filter. The light receiving element 42 outputs a detection pulse according to the received light intensity. The rotary reflecting mirror 41 is a driving unit 44
Is rotated at a constant angular velocity. The detection pulse output from the light receiving element 42 is input to the waveform processing unit 45, and after being subjected to liquid form processing, is output from the output terminal.

FIG. 8 is a diagram showing an electric circuit configuration of the optical coordinate input device according to the present invention. As described above, the present coordinate input device has a pair of light source units 4 and 5 and a calculation unit 6, and these portions are electrically connected to each other by a cable.

As shown, the light receiving element 42 of one light source unit 4 outputs a detection pulse D1. The detection pulse D1 includes two types: a reference detection pulse DIREF corresponding to the reflected light directly reflected by the rotary reflecting mirror 41, and a signal detection pulse DISIG corresponding to the reflected light returned by being retroreflected by the coordinate input pen 1. is there. The waveform processing unit 45 is connected to the light receiving element. The waveform processing unit 45 includes an amplification circuit 451 that amplifies the detection pulse D1, a trigger circuit 452 for outputting a trigger signal E1 synchronized with the rising edge of the detection pulse D1, and a trigger signal F1 synchronized with the falling edge. A monostable multivibrator 453 which operates by a trigger signal E1 and outputs a rectangular pulse train G1 synchronized therewith, and a monostable multivibrator which operates by a trigger signal F1 and outputs a rectangular pulse train H1 synchronized therewith 454.
The other light source unit 5 has the same configuration, and the light receiving element 52 is connected to the waveform processing unit 55.

Next, a measurement circuit 60 incorporated in the calculation unit 6 is connected to the waveform processing unit 45. The measuring circuit 60 has a rectangular pulse train G1 and
Measure the rectangular pulse time interval of H1. A calculation circuit 61 is connected to the measurement circuit 60, and based on the measurement result, the declination θ ₁
Is calculated. Meanwhile the waveform processing section 55 is measuring circuit 63 and the calculation circuit 64 is built on the basis of the rectangular pulse train G2 and H2 are connected in series to the calculation unit 6 obtains the argument theta _2. The waveform processing units 45 and 55, the measurement circuits 60 and 63, and the calculation circuits 61 and 64, described above, perform the declination θ ₁ based on the detection pulses D1 and D2.
And circuit means for determining θ ₂ .

The arithmetic circuit 62 is connected to the calculation circuit 61 and 64, resulting deflection angle data theta ₁ and theta ₂ and advance the coordinates designated by the input pen on the basis of the set input between have been two-point distance data L Is calculated. An electronic OHP using a CRT 7 or a transmissive liquid crystal display element is connected to the arithmetic circuit 62, and visually displays the result of the coordinate calculation. Also infrared detection circuit 65
Is also connected to the arithmetic circuit 62, detects the infrared switch input signal from the input pen, actually operates the arithmetic circuit 62, and executes the input designated coordinate value calculation.

Finally, the operation of the optical coordinate input device according to the present invention will be described. First, as shown in FIG. 1, the light source unit 3 is placed on the upper end of the input coordinate plane given, and the distance L between the pair of light source units 4 and 5 (more precisely, the pair of specific points P ₁ and P _The distance between the _two is set and input to the arithmetic circuit 62 of the calculation unit 6.

Then placed on the coordinate plane 2 provided a light retro-reflective input pen 1, the central axis P ₀ desired coordinate point P (x, y)
Adjust to Such coordinate designation using the input pen 1 can be actually performed continuously because the angular scanning speed of the incident light beam is high.

Subsequently, the pair of light source units 4 and 5 are operated, the incident light beam is angularly scanned, triangulation is performed, and the value of the coordinate P (x, y) is calculated. This operation will be described with reference to the timing chart of FIG. First, the argument θ ₁ is determined by the circuit means described above. At this time, the light receiving element 42 outputs the detection pulse D1. The detection pulse D1 is a reference detection pulse DI corresponding to the reflected light directly reflected by the circuit reflecting mirror.
There are two types, REF and a signal detection pulse DISIG corresponding to the reflected light that has been retroreflected by the coordinate input pen and returned. The signal time interval between the reference detection pulse DIREF and the subsequent signal detection pulse DISIG is t1, and the adjacent reference detection pulse DIREF
If the reference time interval between is represented by T1, the argument θ ₁ is calculated by the following relational expression (3).

However, the detection pulse D1 has a substantially trapezoidal shape as shown and does not have a clear peak. Therefore, the waveform processing of the detection pulse is performed to obtain the time interval between the detection pulses. That is, after the detection pulse D1 is amplified, it is processed by the trigger circuit 452 to output the trigger signals E1 and F1. The trigger signal E1 has a trigger pulse in response to the rising edge of the detection pulse, and the trigger signal F1 has a trigger pulse in response to the falling edge of the detection pulse.

Next, the monostable multivibrator 453 outputs the trigger signal E1.
And outputs a rectangular pulse train G1 having a constant pulse width in response to the trigger pulse. Similarly, the monostable multivibrator 454 outputs a rectangular pulse train H1 having a constant pulse width in response to the trigger pulse of the trigger signal F1.

Further, the measurement circuit 60 measures the pulse interval of the rectangular pulse train G1, and obtains a rising reference signal time interval t1 + and a rising reference reference time interval T1 +. The measuring circuit 60 also measures the pulse interval of the other rectangular pulse train H1, and obtains a signal time interval t1− based on falling and a reference time interval T1− based on falling.

Then, the calculation circuit 61 calculates the following relational expressions (4) and (5).
, The required signal time interval t1 and the reference time interval T1 are calculated.

In this manner, by averaging the time interval data actually measured on the rising and falling standards, it is possible to obtain the time interval data on the basis of the center of the pulse width of each detection pulse.
Further, the calculation circuit 61 calculates the obtained time interval data t1 and T1.
Is used to determine the argument θ ₁ according to the relational expression (3).

In the same manner, the other declination θ ₂ is calculated. That is. The detection pulse D2 output from the light receiving element 52 is processed by the waveform processing unit 55, and the rectangular pulse trains G2 and H2 are formed based on the obtained trigger signals E2 and F2, and the measurement circuit 63 measures the rectangular pulse interval. The rising and falling reference time interval data t2 + and T2 + and the falling and falling reference time interval data t2− and T2− are obtained. Further, the declination θ ₂ is calculated by the calculation circuit 64 according to the following relational expressions (6), (7) and (8).

Finally, the arithmetic circuit 62 calculates the coordinates P (x) designated by the algorithm according to the above-mentioned relational expressions (1) and (2) based on the obtained argument data θ ₁ and θ ₂ and the distance data L set in advance. , y).

[Effects of the Invention] As described above, according to the present invention, a two-dimensional coordinate input device includes a light retroreflection-type input device and a laser light source unit, and a principle of triangulation by angular scanning of a laser beam. Therefore, the input device can be applied to any given coordinate plane, and has an effect of being extremely excellent in versatility. Also, by using a pen type input device,
There is an effect that the coordinate input operation becomes easy and convenient.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a coordinate input device, FIG. 2 is an external view of an input pen, FIG. 3 is a reflected laser beam light intensity distribution diagram, and FIG.
FIG. 5 is an enlarged view of the retroreflective layer, FIG. 5 is a sectional view of the input pen, FIG. 6 is a circuit diagram of the input pen, FIG. 7 is an optical configuration diagram of a right side light source unit of the coordinate input device light source section, FIG. 8 is a circuit configuration diagram of the coordinate input device, and FIG. 9 is a timing chart of the coordinate input device circuit. 1. Input device (input pen), 2. Coordinate plane, 3. Light source unit,
4,5 light source unit, 6 calculation unit, 40 laser light source, 41
... Rotating reflector, 42 ... Light receiving element, 43 ... Half mirror, 45 ...
Waveform processing unit, 60, 63… Measurement circuit, 61,64… Calculation circuit, 62
… Arithmetic circuit,

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G06F 3/03 G06F 3/033

Claims (8)

(57) [Claims] A central axis for designating coordinates to be input and a cylindrical retroreflection surface surrounding the central axis, the central axis being movably operated along a two-dimensional coordinate plane having a given dimension; A retroreflective coordinate input device for retroreflecting an incident light beam that traverses and reversing a reflected light beam; and angularly scanning along the coordinates from two points placed on the coordinate plane and separated on a reference line And a pair of light source units for receiving the reflected light beam which is retroreflected by the coordinate input device and travels backward by the coordinate input device to generate a detection pulse, and the two points and the coordinate input device based on the detection pulse. Circuit means for determining the declination between each of the optical paths connecting the central axes of the two and the reference line, and a coordinate input device according to the principle of triangulation using the determined declination value and the value of the distance between the two points. For calculating the coordinates specified by Optical two-dimensional coordinate input device comprising a calculation means. 2. A light source unit comprising: a laser light source for generating an incident light beam; a rotary reflecting mirror for angularly scanning the incident light beam; a reflected light directly reflected by the rotating reflecting mirror; and a coordinate input device. 2. The optical system according to claim 1, further comprising: a light receiving element for receiving the reflected light that has been retroreflected by the controller and generating corresponding reference detection pulses and signal detection pulses.
Dimensional coordinate input device. 3. The circuit means for measuring a signal time interval between a reference detection pulse and a subsequent signal detection pulse, and a reference time interval between a reference detection pulse and the next reference detection pulse. 3. The optical two-dimensional coordinate input device according to claim 2, further comprising a calculating means for calculating a declination based on a ratio between the signal time interval and the reference time interval. 4. A measuring means for measuring a rise time interval in accordance with a rise of a pair of detection pulses to be measured, a measure means for measuring a fall time interval in accordance with a fall, and a rise time interval. 4. The optical two-dimensional coordinate input device according to claim 3, further comprising: means for calculating a time interval between the pair of detection pulses based on a fall time interval. 5. A writing instrument-shaped gripping member having a central axis and a cylindrical surface along the central axis, and a retroreflective layer for reflecting an incident light ray recursively described on the cylindrical surface. An optical retroreflective coordinate system for inputting coordinates by adjusting the center axis to a specific point on the coordinate plane by moving the coordinate plane while holding the center axis almost perpendicular to the given coordinate plane. Input pen. 6. An optical retroreflective coordinate input pen according to claim 5, wherein said retroreflective layer is composed of a set of retroreflective elements each having an optical retroreflective effect. 7. An assembly of said recursive elements comprises a myriad of photorefractive microspheres dispersed along a cylindrical surface.
4. An optical retroreflective coordinate input pen according to claim 1. 8. A shaft member which is arranged at a tip end and which performs switch input by moving in a central axis direction,
6. The optical retroreflective coordinate input pen according to claim 5, further comprising: a light-emitting portion disposed on a top portion and optically emitting a switch input signal in response to a switch input.