JPH11110116A - Optical position detector - Google Patents

Abstract

(57) [Summary] [Problem] To determine a specific pointing object such as a finger or a pen for giving an instruction on a coordinate plane by measuring a cutoff range of scanning light on a coordinate plane formed by the pointing object. And an optical position detecting device for accurately detecting the indicated position. SOLUTION: A retroreflective sheet 7 is provided outside at least three sides (for example, left and right and lower sides) of a quadrilateral display screen 10 serving as a coordinate plane, and light is emitted in a plane substantially parallel to the display screen. The two light transmitting / receiving units 1a and 1b each having a light scanning member for angularly scanning the light and a light receiving member for receiving the light reflected by the retroreflective sheet 7 are disposed outside both corners of the upper side of the display screen 10. Deploy. Based on the angle of the scanning light at the timing of the rise and fall of the light receiving level at the light receiving member, the cutoff range of the finger as the indicator is determined as dθ = θ2−θ1, dφ = φ2−φ1. The type of the pointer is determined according to the obtained blocking range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical position detecting device for optically detecting a designated position on a coordinate plane such as a display screen.

[0002]

2. Description of the Related Art When an input operation is performed on information displayed on a screen of a personal computer or the like by a touch method, it is necessary to detect a contact position (designated position) on the display screen with high accuracy. is there. As a method of detecting a designated position on a display screen serving as such a coordinate plane, a “Carroll method” (US Pat. No. 4,267,443) is known. In this method, a light matrix is formed on the front surface of the display screen by arranging a light emitting element and a light receiving element in a frame on the front surface of the display screen to detect a light blocking position due to contact of a finger or a pen. . In this method, high S /
N can be obtained and the application can be extended to a large display device. However, since the detection resolution is proportional to the arrangement interval of the light emitting element and the light receiving element, the arrangement interval is increased in order to increase the detection resolution. Must be narrow. Therefore, even when a large screen is touched by a thin object such as a pen tip, in order to accurately detect the contact position, the number of light emitting elements and light receiving elements to be arranged increases, and the configuration is large. There is a problem that the signal processing becomes complicated and signal processing becomes complicated.

Another optical position detecting method is disclosed in Japanese Patent Application Laid-Open No. 57-211637. In this method, a focused light such as a laser beam is angularly scanned from the outside of a display screen, and an angle at which a dedicated pen is present is obtained from two timings of reflected light from a dedicated pen having reflecting means. By applying the angle to the principle of triangulation, the position coordinates are detected by calculation. With this method, the number of parts can be significantly reduced, and high resolution can be achieved. However, there is a problem in operability such as the necessity of using a dedicated reflecting pen, and the position of a finger, an arbitrary pen, or the like cannot be detected.

[0004] Still another optical position detecting method is proposed in Japanese Patent Application Laid-Open No. 62-5428. This method
Light retroreflectors are arranged on both side frames of the display screen, and the light returned by the light retroreflectors of the angularly scanned light beams is detected. Is found, and the position coordinates are detected from the found angle by the principle of triangulation. in this way,
Since the number of parts is small, the detection accuracy can be maintained, and the position of a finger, an arbitrary pen or the like can be detected.

[0005]

However, in the system disclosed in Japanese Patent Application Laid-Open No. Sho 62-5428, the detected contact position is actually touched under the influence of the size or position of the obstacle. Position may be shifted.
Further, when detecting the contact position of the finger, if a hand or elbow other than the finger is struck, there is a problem that the position of the hand or elbow is erroneously detected as the contact position, and the position of the finger cannot be specified.

In a conventional device of this type, a light-emitting means for emitting scanning light is often arranged so that the optical axis of the light emitted from the light-emitting means is parallel to the scanning surface, and the light is reflected. In many cases, the light receiving means for receiving the scanning light is also arranged such that the directional direction of the received light is parallel to the scanning surface. For this reason, the optical transmission / reception means has become relatively large, which has often been an obstacle to miniaturization of the entire apparatus.

Further, the display screen is generally rectangular (rectangular), and the scanning area of this type of device is often designed in accordance with the display screen. In this case, the light emitting means is provided on the edge of the display screen. By adopting an arrangement in which the light receiving means, the light scanning means and the like are arranged in parallel, the size of the apparatus is often reduced. However, in such an arrangement,
A problem arises in that the scanning light from the light scanning unit is blocked by the light emitting unit, the light receiving unit, and the like, and a sufficient scanning angle cannot be obtained.

The present invention has been made in view of such circumstances, and determines the size of a light blocking object (indicating object) to accurately determine the position of the indicating object on the coordinate plane. It is an object of the present invention to provide an optical position detecting device capable of detecting a position at a time.

[0009] Another object of the present invention is to provide a method for instructing a position by using a finger or a pen by invalidating the detection position when the hand or elbow is struck. An object of the present invention is to provide an optical position detecting device capable of detecting a position.

Still another object of the present invention is to provide a light-emitting means for emitting scanning light, wherein the light-emitting means is arranged so that the optical axis of the light emitted by the light intersects the scanning surface, and the light-receiving means receives the reflected scanning light. The means is also arranged so that the direction of the light to be received intersects the scanning surface, so that the size of the light transmitting / receiving means can be reduced,
An object of the present invention is to provide an optical position detecting device that can be downsized as a whole.

Still another object of the present invention is to provide an arrangement in which the light receiving means and the light scanning means are arranged farther from the edge of a generally rectangular display screen than the light emitting means, so that the scanning light by the light scanning means can be obtained. It is an object of the present invention to provide an optical position detecting device that can prevent light from being blocked by a light emitting unit, a light receiving unit, and the like, and can obtain a sufficient scanning angle.

[0012]

According to a first aspect of the present invention, there is provided an optical position detecting device for optically detecting a position on a coordinate plane designated by an indicator, wherein the optical recursive member is provided outside the coordinate plane. Reflecting means, optical scanning means for angularly scanning light in a plane substantially parallel to the coordinate plane, and light receiving means for receiving light reflected by the light retroreflecting means for light scanned by the optical scanning means At least two sets of light transmitting and receiving means having: a measuring means for measuring a scanning light blocking range on a coordinate plane formed by the pointer based on a scanning angle of the light scanning means and a light receiving result of the light receiving means And characterized in that:

According to a second aspect of the present invention, in the first aspect, the coordinate plane is a quadrilateral display screen, and the light retroreflecting means is provided on a light scanning surface outside at least three sides of the display screen. On the other hand, it is assumed that the light reflecting surface is disposed substantially vertically, and that two sets of light transmitting / receiving means are disposed outside one side of the coordinate plane where the light retroreflecting means is not disposed. Features.

According to a third aspect of the present invention, there is provided an optical position detecting device according to the second aspect, wherein a line segment connecting the centers of the two sets of light transmitting / receiving means is connected to the second line.
The distance d between one side of the coordinate plane on which the set of light transmitting and receiving means is arranged is the following equation: d ≧ dθ × L / 4δ where dθ: measurement accuracy (spreading angle of scanning light) δ: detection accuracy L: It is set so as to satisfy the reference line length (the distance between the two optical transmission / reception units).

According to a fourth aspect of the present invention, in the optical position detecting device according to the second aspect, a part or all of the light retroreflecting means is 2 or more.
It is characterized by being arranged in a sawtooth shape so as to be more perpendicular to the projection light from the set of light transmitting and receiving means.

According to a fifth aspect of the present invention, there is provided the optical position detecting device according to the second aspect, wherein the coordinate plane is rectangular, and two sets of light transmitting / receiving means are arranged along one of the short sides of the coordinate plane. Features.

According to a sixth aspect of the present invention, there is provided an optical position detecting device according to any one of the first to fifth aspects, further comprising means for calculating a pointed position by the pointer using a specific point in the measured cutoff range. .

An optical position detecting device according to a seventh aspect is characterized in that in any one of the first to sixth aspects, information on a scanning angle is obtained from information on the scanning time of the optical scanning means.

An optical position detecting device according to an eighth aspect of the present invention is characterized in that, in the seventh aspect, there is provided means for calculating a sectional length of the pointing object based on the measured blocking range and the calculated pointing position.

According to a ninth aspect of the present invention, in the optical position detecting device according to the eighth aspect, means for storing size information of a plurality of types of objects, size information of the pointer obtained from the calculated section length,
The information processing apparatus further includes a comparing unit that compares the stored pieces of size information of the plurality of types of objects, and a determining unit that determines a type of the pointer according to a comparison result of the comparing unit.

According to a tenth aspect of the present invention, in the ninth aspect, when the determining means determines that the pointer is other than the specific pointer, the measured blocking range and the calculated pointing position are invalidated. It is characterized by comprising means.

According to an eleventh aspect of the present invention, there is provided the optical position detecting device according to any one of the first to tenth aspects, wherein the at least one optical position detecting device is provided near the coordinate plane and receives scanning light from the optical scanning means.
The present invention is characterized in that two light receiving elements are provided, and the timing at which the light receiving elements receive the scanning light is the timing of starting and / or ending the optical scanning on the coordinate plane.

According to a twelfth aspect of the present invention, there is provided an optical position detecting device according to any one of the first to eleventh aspects, wherein the reflecting means is provided near the coordinate plane and reflects the scanning light from the optical scanning means toward the light receiving means. And a timing at which the light reflected from the reflecting means is received by the light receiving means is set as a timing of starting and / or ending the optical scanning on the coordinate plane.

According to a thirteenth aspect of the present invention, there is provided an optical position detecting device according to any one of the second to eleventh aspects, wherein the end of the light retroreflecting means facing one side of the coordinate plane where the light retroreflecting means is not disposed. The change in the amount of reflected light is used as the start and / or end timing of one cycle of optical scanning on the coordinate plane.

According to a fourteenth aspect of the present invention, there is provided the optical position detecting device according to any one of the first to eleventh aspects, wherein an area in which the pointer cannot enter is provided between the coordinate plane around the coordinate plane and the light retroreflecting means. It is characterized by having such a configuration.

According to a fifteenth aspect of the present invention, in any one of the first to fourteenth aspects, the scanning light is pulsed light, and the optical scanning means has a control means for controlling pulsed light emission. And

The optical position detecting device according to a sixteenth aspect is characterized in that, in the fifteenth aspect, the scanning light is a pulse light having a period sufficiently short for a required resolution.

According to a seventeenth aspect of the present invention, in the optical position detecting device according to the fifteenth aspect, the control means controls at least one parameter among a light emission time per scan light, a light emission intensity per light, and a light emission cycle. It is characterized by having means for adjusting.

In an eighteenth aspect of the present invention, the optical position detecting device according to the fifteenth aspect is characterized in that the control means has means for adjusting the timing of starting the light scanning.

An optical position detecting device according to a nineteenth aspect is characterized in that, in the first or second aspect, the sectional shape of the light scanned by the optical scanning means is flat.

According to a twentieth aspect of the present invention, in the first or second aspect, the sectional shape of the light scanned by the optical scanning means is flat in a direction parallel to the coordinate plane.

According to a twenty-first aspect of the present invention, there is provided the optical position detecting device according to the first or second aspect, wherein the light scanned from one of the two light transmitting / receiving means is not incident on the other light receiving means. It is characterized by having.

An optical position detecting device according to a twenty-second aspect is characterized in that the optical position detecting device according to the first or second aspect further comprises a light receiving amount control means for controlling a light receiving amount of each of the two sets of light transmitting / receiving means to be constant. I do.

According to a twenty-third aspect of the present invention, in the optical position detecting device according to the twenty-second aspect, the light receiving amount control means controls the intensity of light scanned by the light scanning means so as to keep the light receiving amount by the light receiving means constant. It is characterized by being done.

According to a twenty-fourth aspect of the present invention, in the twenty-second aspect, the light-receiving amount control means controls an amplification factor of a level of a light-receiving signal of the light-receiving means in order to keep a light-receiving amount of the light-receiving means constant. It is characterized by being done.

According to a twenty-fifth aspect of the present invention, there is provided the optical position detecting device according to the first or second aspect, wherein storage means for storing information on an amount of light received in an initial state by the light receiving means of each of the two sets of light transmitting / receiving means; And a comparing means for comparing the stored information on the amount of received light with the amount of light received by the light receiving means.

According to a twenty-sixth aspect of the present invention, there is provided an optical position detecting device according to the first or second aspect, wherein storage means for storing, as a digital signal, information on the amount of light received by the light receiving means of each of the two sets of light transmitting / receiving means, The digital signal processing system is characterized by comprising conversion means for converting the digital signal stored in the storage means into an analog signal, and comparison means for comparing the amount of light received by the light receiving means with the analog signal resulting from the conversion by the conversion means.

An optical position detecting device according to a twenty-seventh aspect of the present invention is the optical position detecting device according to the first or the second aspect, further comprising switching means for switching the intensity of the light scanned by the optical scanning means in at least two stages, and the light scanned by the optical scanning means. The switching means is controlled in accordance with the scanning angle of (1).

According to a twenty-eighth aspect of the present invention, in the first or second aspect, the light scanned by the optical scanning means is directly incident on the light receiving means at the start of scanning without passing through the retroreflecting means. A first comparing means for comparing a light receiving amount signal from the light receiving means with a relatively large first reference value, and a second comparing means for comparing with a relatively small second reference value. The output of the comparison result by the first comparing means is set as the timing of starting scanning.

An optical position detecting device according to a twenty-ninth aspect is characterized in that, in the twenty-eighth aspect, at least two or more time-measuring means are provided, and the start of scanning, which is a comparison result output by the first comparing means, is started. The switching means is switched at a point in time when the timing means measures a predetermined time.

The optical position detecting device according to a thirty-fifth aspect is characterized in that, in the twenty-eighth aspect, the optical position detecting device further comprises at least four time-measuring means using a start of scanning, which is a comparison result output by the first comparing means, as a start trigger, and At the timing when the output of the comparing means changes from true to false, two of the four timing means are stopped, and at the timing when the output of the second comparing means changes from false to true, the other two timing means are stopped. Is stopped.

The optical position detecting device according to claim 31 is characterized in that, in claim 28, the optical position detecting device according to claim 28, further comprising four time measuring means using the timing when the output of the second comparing means changes from false to true as a start trigger, and At the timing when the output of the means changes from true to false, two of the four timing means are stopped, and at the timing when the output of the second comparing means changes from false to true, the other two timing means are stopped. It is characterized by being stopped.

An optical position detecting apparatus according to claim 32, wherein at least two time measuring means for measuring an interval of a scan start timing, which is a comparison result output by the first comparing means, are provided. In addition, the present invention is characterized in that the result of time measurement by the four time measuring means is corrected by the result of time measurement by at least two time measuring means.

An optical position detecting device according to a thirty-third aspect is a device for touching a display screen of a flat display with an indicator and optically detecting the touched position, and is disposed outside three sides of the display screen. Optical retroreflecting means, and optical scanning that is arranged outside one side of the display screen where the optical retroreflecting means is not disposed, and angularly scans light in a plane substantially parallel to the display screen. Means, and at least two sets of light transmitting / receiving means having light receiving means for receiving light reflected by the light retroreflecting means of light scanned by the light scanning means; scanning angle in the light scanning means and light receiving in the light receiving means And measuring means for measuring a blocking range of scanning light on a display screen formed by the pointer based on the result.

An optical position detecting device according to a thirty-fourth aspect is characterized in that, in the thirty-third aspect, the flat display is a plasma display.

The optical position detecting device according to claim 35 is a device for optically detecting a position on a coordinate plane designated by an indicator, wherein a light retroreflecting means provided outside the coordinate plane;
Light emitting means; light scanning means for angularly scanning light emitted by the light emitting means in a plane substantially parallel to a coordinate plane; and light retroreflecting light scanned by the light scanning means At least two sets of light transmitting / receiving means each having a light receiving means for receiving light reflected by the means, and a coordinate plane formed by the pointing object based on a scanning angle by the light scanning means and a light receiving result by the light receiving means. Measuring means for measuring the cutoff range of the scanning light, wherein the light emitting means is arranged such that the optical axis of the light emitted by the light intersecting the light scanning surface by the light scanning means, Are arranged so that the direction of the directivity of the light received by the light scanning means crosses the scanning surface of the light by the light scanning means.

The optical position detecting device according to claim 36 is a device for optically detecting a position on a coordinate plane designated by an indicator, wherein a light retroreflecting means provided outside the coordinate plane,
Light emitting means; light scanning means for angularly scanning light emitted by the light emitting means in a plane substantially parallel to a coordinate plane; and light retroreflecting light scanned by the light scanning means At least two sets of light transmitting / receiving means each having a light receiving means for receiving light reflected by the means, and a coordinate plane formed by the pointing object based on a scanning angle by the light scanning means and a light receiving result by the light receiving means. Measuring means for measuring the cutoff range of the scanning light, the light emitting means is arranged so that the path of the light emitted by the light to the light scanning means is away from the edge of the coordinate plane in a portion close to the light emitting means side. The light receiving means is arranged so that the direction of the directivity of the light received by the light receiving means is away from the edge of the coordinate plane in a portion close to the light receiving means side.

[0048]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to the drawings showing the embodiments.

(First Embodiment) FIG. 1 is a schematic diagram showing a basic configuration of an optical position detecting device (hereinafter, referred to as the present invention) according to a first embodiment of the present invention.

In FIG. 1, reference numeral 10 denotes a display screen of a CRT or a flat display panel (PDP, LCD, EL, etc.) in an electronic device such as a personal computer, or a projection type video display device. 92.0 cm in the direction x 51.8 cm in the vertical direction, diagonal 10
It is configured as a display screen of a PDP (plasma display) having a display size of 5.6 cm. As will be described later, a light emitting element, a light receiving element, a polygon mirror, and the like are provided outside both short sides (one side on the right side in this embodiment) of this rectangular display screen 10 serving as a first coordinate plane. Light transmission / reception units 1a and 1b each including an optical system including the light transmission / reception unit are provided. The retroreflective sheet 7 is provided on three sides of the display screen 10 except for the right side, that is, outside the upper and lower sides and the left side. These components are provided on an eave-shaped shield 51 described below, which is installed on the front side of the housing.
It is arranged in a state shielded by.

Reference numeral 70 is a light shielding member.
The light shielding member 70 prevents light from directly entering between the two light transmitting / receiving units 1a and 1b, specifically, prevents light projected from the light transmitting / receiving unit 1a from entering the light transmitting / receiving unit 1b, and vice versa. So that light projected from the light transmitting / receiving unit 1b does not enter the light transmitting / receiving unit 1a.
It is provided on a line connecting the two light transmitting / receiving units 1a and 1b. Also, the light shielding member 70 has a light reflectance of practical use.
The height of the retroreflective sheet 7 is approximately the same as that of the retroreflective sheet 7.

Reference symbol S indicates a cross section of a human finger as an obstruction (pointer).

FIG. 2 is a schematic diagram showing the internal configuration and optical paths of the light transmitting / receiving units 1a and 1b. Both light transmitting and receiving unit 1
Reference numerals a and 1b denote light emitting elements 11a and 11b each formed of a laser diode for emitting an infrared laser, and light emitting elements 11a and 11b.
Collimator lenses 12a and 12b for converting the laser beam from the laser beam 11b into parallel light, light receiving elements 13a and 13b for receiving the reflected light from the retroreflective sheet 7, and the light receiving element 1
Visible light cut filter 14 that blocks visible light components of external light from display screens, illumination lights, and the like incident on 3a and 13b.
a, 14b, half mirrors 15a, 15b for guiding the reflected light to the light receiving elements 13a, 13b, and the light emitting element 11
In the present embodiment for angularly scanning the laser beams from the laser beams a and 11b, there are quadrangular polygon mirrors 16a and 16b and the like.

After the laser beams emitted from the light emitting elements 11a and 11b are collimated by the collimator lenses 12a and 12b and transmitted through the half mirrors 15a and 15b, the display screen 1 is rotated by the rotation of the polygon mirrors 16a and 16b.
The light is angularly scanned in a plane substantially parallel to 0 and projected on the retroreflective sheet 7. Then, the reflected light from the retroreflective sheet 7 is reflected by the polygon mirrors 16a and 16b and the half mirrors 15a and 15b, passes through the visible light cut filters 14a and 14b, and passes through the light receiving element 13
a, 13b. However, when an obstruction (indicator) exists in the optical path of the projection light, the projection light is blocked, and the reflected light does not enter the light receiving elements 13a and 13b. The rotation of the polygon mirrors 16a and 16b realizes angular scanning of the laser light of 90 degrees or more.

Each of the light transmitting / receiving units 1a and 1b has a light emitting element driving circuit 2a, 2 for driving the light emitting element 11a, 11b.
b, light receiving signal detecting circuits 3a and 3b for converting the light receiving amounts of the light receiving elements 13a and 13b into electric signals, and a polygon control circuit 4 for controlling the operations of the polygon mirrors 16a and 16b. Reference numeral 5 denotes an MPU that measures and calculates the position and size of an obstruction (indicator) S such as a finger or a pen, and controls the operation of the entire apparatus.
This is a display device for displaying the measurement results and the like in U.

In such an apparatus of the present invention, as shown in FIG. 1, for example, regarding the light transmitting / receiving unit 1b, the projected light from the light transmitting / receiving unit 1b is
First, scanning is performed in the counterclockwise direction in FIG. 1 from the position shielded by the light shielding member 70, and reaches the position (Ps) where the light is reflected by the leading end of the retroreflective sheet 7 and becomes the scanning start position. The light is reflected by the retroreflective sheet 7 up to the position (P1) reaching one end of the obstacle S, but is blocked by the obstacle S up to the position (P2) reaching the other end of the obstacle S. The light is reflected by the retroreflective sheet 7 until reaching the subsequent scanning end position (Pe).

However, in the light transmitting / receiving unit 1a, scanning of light is performed clockwise in FIG. Here, the light transmission / reception unit 1a sets the lower side of the display screen 10 in the clockwise direction in FIG. 1 as the scanning start direction, and conversely, the light transmission / reception unit 1b sets the upper side of the display screen 10 in the counterclockwise direction in FIG. Will be described as the scanning start direction.

For example, in the case of the light transmitting / receiving unit 1b,
Either the upper side or the left side of the display screen 10 may be the scanning start direction. However, when viewed from the light transmitting / receiving unit 1b, the amount of reflected light is large because the upper side of the display screen 10 is closer in distance than the lower side. In addition, since the reflection surface of the retroreflective sheet 7 is substantially perpendicular to the upper side of the display screen 10 and the amount of reflected light is large, the upper side of the display screen 10 is set as the scanning start direction. In other words, in the case of the light transmitting / receiving unit 1b, if the lower side of the display screen 10 is the scanning start direction, the lower side of the display screen 10 is farther from the upper side in terms of distance, so that the amount of reflected light at the start of scanning becomes smaller. ,
In addition, since the reflection surface of the retroreflective sheet 7 is curved, the amount of reflected light is small. However, the curvature of the retroreflective sheet 7 is not an essential problem, and it is of course possible to adopt a configuration in which the sheet is not curved.

FIG. 2 is a schematic diagram for explaining the optical path and operation of the two light transmitting / receiving units 1a and 1b. In the present invention, the two light transmitting / receiving units 1a (1
b) is actually configured as shown in the schematic plan view of FIG. 41, the schematic side view of FIG. 42, and the schematic perspective view of FIG.

The light transmitting / receiving unit 1a (1b)
A light emitting element 11a (11b) such as a semiconductor laser generator and a light receiving element 13a (13b) for receiving light reflected from the retroreflective sheet 7 are housed inside the light emitting element a (10b). Prism mirrors 17a and 17b are arranged immediately above 11a (11b), and a half mirror 15a is arranged immediately above light receiving element 13a (13b).
(15b) is arranged. Further, the housing 10a (10
A polygon mirror 16a (16b) is attached to a character of a pulse motor (not shown) on the opposite side of the prism mirror 17a (17b) across the half mirror 15a (15b) on the upper surface of (b).

In FIG. 41, FIG. 42 and FIG.
The collimator lenses 12a and 12b and visible light cut filters 14a and 14b shown in FIG.

The light transmitting / receiving unit 1a (1b) as described above
The laser light emitted from the light emitting element 11a (11b) is refracted by the prism mirror 17a (17b), passes through the half mirror 15a (15b), is reflected by the polygon mirror 16a (16b), and is retroreflected. It is projected on the sheet 7. The light reflected by the retroreflective sheet 7 returns to the polygon mirror 16a (16b) to be reflected, enters the half mirror 15a (15b), and finally receives the light receiving element 1
The light is received by 3a (13b).

As shown in FIGS. 41 to 43, the light transmitting / receiving unit 1 of the device of the present invention is used.
In a (1b), the light emitting element 11a (11b) is arranged such that the optical path from the light emitting element 11a (11b) to the polygon mirror 16a (16b) is further away from the edge of the display screen 10 on the light emitting element 11a (11b) side, and the light receiving element 13a (13b) Are arranged on the housing 10a (10b) such that the optical path from the polygon mirror 16a (16b) is further away from the edge of the display screen 10 on the light receiving element 13a (13b) side.

The arrangement of the light emitting element 11a (11b) and the light receiving element 13a (13b)
The scanning light by 6a (16b) is applied to the half mirror 15a (1
5b) and the problem of being not sufficiently scanned in the direction of the display screen 10 due to being blocked by the prism mirror 17a (17b).

Further, the light transmitting / receiving unit 1a of the device of the present invention
In (1b), the light emitting element 11a (11b) is arranged in the housing 10a (10b) such that the direction of emission of the laser beam is orthogonal to the display screen 10, in other words, the scanning surface of the polygon mirror 16a (16b). The light receiving element 13a (13b) is also placed in the housing 10a (10b) so that the direction of the directivity of the light reception is orthogonal to the display screen 10, in other words, the scanning surface of the polygon mirror 16a (16b). Are located.

The arrangement of the light emitting element 11a (11b) and the light receiving element 13a (13b)
(11b) The light emission direction of the laser light is changed to the display screen 10
In other words, rather than disposing the light receiving element 13a (13b) on the housing 10a (10b) so as to be parallel to the scanning surface of the polygon mirror 16a (16b), the direction of the light receiving element 13a (13b) is displayed. It is more effective to reduce the size of the light transmitting / receiving unit 1a (1b) than disposing the light transmitting / receiving unit 1a (1b) on the housing 10a (10b) so as to be parallel to the screen 10, in other words, the scanning surface of the polygon mirror 16a (16b). Play.

In the device of the present invention, as described above, the light emitting element 11a (11b) has its laser light emitting direction orthogonal to the scanning surface of the polygon mirror 16a (16b), and the light receiving element 13a (13b) also has a light emitting direction. Although the direction of the directivity of the received light is arranged so as to be orthogonal to the scanning plane by the polygon mirror 16a (16b), the same applies if the direction is crossed at a certain angle, for example, 60 °. It goes without saying that the effect is exhibited.

As shown in FIG. 1, the retroreflective sheet 7 has an opening at the side where the two light transmitting / receiving units 1a and 1b are arranged, and surrounds the display screen 10 in a “U” shape. Are located in Further, reference numeral 7
a, 7b, both light transmitting and receiving units 1
a, 1b, where the light projection angle of the light from the retroreflective sheet 7 to the retroreflective sheet 7 is reduced, specifically, the two light transmitting / receiving units 1a, 1b.
On both sides (upper side and lower side in FIG. 1) orthogonal to the side on which the is disposed, the retroreflective sheet is installed in a sawtooth shape at a portion far from both light transmitting / receiving units 1a and 1b. .

With the sawtooth portions 7a and 7b of the retroreflective sheet, for example, the projection light from the light transmitting / receiving unit 1b scans from the position Ps to the position P3 of one end of the sawtooth portion 7b of the retroreflective sheet. The angle of incidence on the retroreflective sheet 7 gradually decreases with progress, so that the amount of reflected light also decreases accordingly. However, from the position P3 at one end of the sawtooth portion 7b of the retroreflective sheet to the position P4 at the other end.
Until this time, the light is incident on the sawtooth-shaped portion 7b of the retroreflective sheet at a substantially right angle, so that further reduction in the retroreflectivity is avoided.

FIG. 3 is a block diagram showing the relationship between MPU 5 and other circuits. The polygon control circuit 4 includes a pulse motor 21 for rotating the polygon mirrors 16a and 16b.
And a pulse motor drive circuit 22 for driving the pulse motor 21, and encoders 23a and 23b for detecting the encode signals of the rotation angles of the polygon mirrors 16a and 16b.

The MPU 5 includes light emitting element drive circuits 2a, 2b
, And the light emitting element driving circuits 2 a and 2 b are driven in accordance with the driving control signal, and the light emitting element 11
The light emission operations of a and 11b are controlled. The light receiving signal detection circuits 3a and 3b send the light receiving signal of the light reflected by the light receiving elements 13a and 13b to the MPU 5. Further, the MPU 5 sends a drive control signal for driving the pulse motor 21 to the pulse motor drive circuit 22. The encoders 23a and 23b detect the encode signals of the rotation angles of the polygon mirrors 16a and 16b and send them to the MPU 5. The MPU 5 receives the light receiving signals from the light receiving elements 13a, 13b and the encoders 23a,
The position and the size of the obstruction (pointer) are measured based on the encode signal from 23b, and the measurement result is displayed on the display device 6. The display device 6 can also serve as the display screen 10.

Further, the MPU 5 stores two timers (first timer 24a and second timer 24b) having a time keeping function and information on the size of an assumed obstacle (pointer). A read-only memory (ROM) 25 and a writable memory (RAM) 26 are built-in.

Next, the position detecting operation of the device of the present invention will be described with reference to the schematic diagram of FIG. However, in FIG. 4, components other than the light transmitting / receiving units 1a and 1b, the retroreflective sheet 7, and the display screen 10 are omitted. Also, a case is shown in which a finger is used as the pointer.

The MPU 5 controls the polygon control circuit 4 to rotate the polygon mirrors 16a and 16b in the light transmitting and receiving units 1a and 1b, thereby causing the light emitting elements 11a and 1b to rotate.
The laser beam from 1b is angularly scanned. As a result, the reflected light from the retroreflective sheet 7 is reflected by the light receiving elements 13a and 13b.
Incident on. In this way, the amount of light received by the light receiving elements 13a and 13b is obtained as a light receiving signal output from the light receiving signal detection circuits 3a and 3b. In FIG. 4, θ0 and φ0 denote the angles from the reference line connecting the light transmitting and receiving units 1a and 1b to the end of the retroreflective sheet 7, and
1 and φ1 are the angles from the reference line to the reference line end of the obstruction (indicator), and θ2 and φ2 are the angles from the reference line to the reference line and the opposite end of the obstruction (indicator), respectively. Is shown.

In the timing chart of FIG.
The waveform of the light receiving signal in 3a and 13b is shown. When there is no obstruction (indicator) in the optical path of the scanning light, the reflected light from the retroreflective sheet 7 is incident on the light receiving elements 13a and 13b. The reflected light does not enter the light receiving elements 13a and 13b. Therefore, in the state shown in FIG. 4, no reflected light is incident on the light receiving element 13a when the scanning angle is between 0 ° and θ0, and when the scanning angle is between θ0 and θ1, the light receiving element 13a is not. Reflected light is incident on the object and the scanning angle is θ1
The reflected light does not enter the light receiving element 13a from to.

Similarly, when the scanning angle is between 0 ° and φ0, no reflected light is incident on the light receiving element 13b. When the scanning angle is between φ0 and φ1, the reflected light is incident on the light receiving element 13b, and the scanning is performed. When the angle is between φ1 and φ2, no reflected light is incident on the light receiving element 13b. Such an angle is
It is obtained from the rising or falling timing of the light receiving signal (see FIG. 5). Therefore, the blocking range of the finger of the person as the indicator is dθ = θ2−θ1, dφ = φ2
−φ1.

It is needless to say that θ0 and φ0 are known from the positional relationship between the reference line connecting the light transmitting and receiving units 1a and 1b and the end of the retroreflective sheet 7.

Next, a description will be given of a process for obtaining the coordinates of the center position (pointed position) of the pointer (in this example, the finger) from the cutoff range obtained in this way. First, conversion from an angle to rectangular coordinates based on triangulation will be described. As shown in FIG. 6, the position of the light transmitting / receiving unit 1a is set to the origin O, the upper side and the left side of the display screen 10 are set to the X axis and the Y axis, and the length of the reference line (the distance between the light transmitting / receiving units 1a and 1b) Is L. Further, the position of the light transmitting / receiving unit 1b is assumed to be B. Display screen 1
When the center point P (Px, Py) pointed by the pointer on 0 is located at an angle of θ or φ with respect to the X axis from the light transmitting / receiving units 1a, 1b, respectively, the X coordinate Px, The value of the Y coordinate Py can be obtained according to the following equations (1) and (2) according to the principle of triangulation.

Px = (tan φ) ÷ (tan θ + tan φ) × L (1) Py = (66nθ · tan φ) ÷ (tan θ + tan φ) × L (2)

Since the obstacle (finger) has a size, when the detection angle at the rising / rising timing of the detected light receiving signal is employed, as shown in FIG. 7, the obstacle (finger) S 7 at the edge portion (P1 to P in FIG. 7)
4) will be detected. These four points are all different from the designated center point (Pc in FIG. 7). Therefore,
The coordinates of the center point Pc (Pcx, Pc
y). Px = Px (θ, φ), Py = Py
When (θ, φ) is set, Pcx and Pcy can be expressed as the following equations (3) and (4), respectively.

Pcx = Pcx (θ1 + dθ / 2, φ1 + dφ / 2) (3) Pcy = Pcy (θ1 + dθ / 2, φ1 + dφ / 2) (4)

Therefore, θ1 expressed by the equations (3) and (4)
By substituting + dθ / 2, φ1 + dφ / 2 as θ, φ in the above equations (1) and (2), the designated center point P
The coordinates of c can be obtained.

In the above-described example, first, the average value of the angle is obtained, and the average value of the angle is substituted into the conversion formulas (1) and (2) of the triangulation to obtain the center point Pc which is the designated position.
First, the orthogonal coordinates of the four points P1 to P4 are obtained from the scanning angles according to the conversion formulas (1) and (2) of the triangulation, and the average of the obtained coordinate values of the four points is calculated. Thus, the coordinates of the center point Pc can be determined. In addition, it is also possible to determine the coordinates of the center point Pc, which is the designated position, in consideration of the parallax and the visibility of the designated position.

If the scanning angular velocity of the rotation of the polygon mirrors 16a and 16b is constant, the scanning angle is proportional to the rotation time, so that information on the scanning angle can be obtained by measuring the time. FIG. 8 is a timing chart showing the relationship between the light receiving signal from the light receiving signal detection circuit 3a and the scanning angle θ and the scanning time T of the polygon mirror 16a. When the scanning angular velocity of the polygon mirror 16a is constant, and the scanning angular velocity is ω, the scanning angle θ and the scanning time T have a proportional relationship as shown in the following equation (5).

Θ = ω × T (5)

Therefore, the angles θ1 and θ2 at the time of the falling and rising of the light receiving signal are determined by the respective scanning times t1 and t2.
2 and the following equations (6) and (7) hold.

Θ1 = ω × t1 (6) θ2 = ω × t2 (7)

Therefore, when the scanning angular velocities of the polygon mirrors 16a and 16b are constant, the time information is used to calculate
It is possible to measure the cutoff range and coordinate position of the pointer (finger).

FIG. 9 is a flowchart showing an example of an algorithm in the MPU 5 when measuring the time interval during which the reflected light is at a low level using the first timer 24a and the second timer 24b built in the MPU 5. The MPU 5 detects a change in the light reception signal from the light reception signal detection circuits 3a and 3b, and when the level of the signal decreases, the timers 24a and 2
4b is started to start the timing operation, and when the level is recovered, the timers 24a and 24b are stopped and the timing operation is ended.

The MPU 5 first receives the light-receiving signal detection circuit 3a,
The change in the light receiving signal from the light receiving signal 3b is checked (step S1), and it is determined whether or not the light receiving signal from the light receiving signal detecting circuit 3a has changed (step S2). If no change has occurred (NO in step S2), the process proceeds to step S6. If there is a change (YE in step S2)
S), the MPU 5 determines whether or not the level of the received light signal is low (Step S3), and when it is low (Step S3).
Is YES), the first timer 24a is started (Step S)
4) If it is higher (NO in step S3), the first timer 24a is stopped (step S5), and the process proceeds to step S6. In step S6, the MPU 5 determines whether a change has occurred in the light reception signal from the light reception signal detection circuit 3b. If no change has occurred (step S6
NO), the process returns. If a change has occurred (YES in step S6), the MPU 5 determines whether the level of the received light signal is low (step S7), and if it is low (YES in step S7), the second timer 24b.
Is started (step S8), and when it is high (NO in step S7), the second timer 24b is stopped (step S9), and the process returns.

In the apparatus according to the present invention, it is also possible to obtain the cross-sectional length of the obstacle (pointer) from the measured interruption range. FIG. 10 is a schematic diagram showing the principle of the cross-section length measurement. In FIG. 10, D1 and D2 are cross-sectional lengths of the blocking object S viewed from the light transmitting and receiving units 1a and 1b, respectively. First, the positions O (0,0), B of the light transmitting / receiving units 1a, 1b
From (L, 0), the center point Pc of the obstacle S (Pcx, Pc
The distances OPc (r1) and BPc (r2) to y) are obtained as in the following equations (8) and (9). OPc = r1 = (Pcx ² + Pcy ² ) ^1/2 (8) BPc = r2 = {(L−Pcx) ² + Pcy ² } ^1/2 (9)

Since the section length can be approximated by the product of the distance and the sine value of the cutoff angle, the section lengths D1 and D2 are given by the following (1).
It can be measured according to equations (0) and (11).

D1 = r1 · sindθ = (Pcx ² + Pcy ² ) ^1/2 · sinθ (10) D2 = r2 · sinφ = ｛(L−Pcx) ² + Pcy ² ｝ ^1/2 · sinφ (11)

If θ, φ ≒ 0, sin
dθ ≒ dθ ≒ tan θ, sinφ ≒ dφ ≒ tand
Since it can be approximated to φ, s in equations (10) and (11)
Instead of indθ and sinφ, dθ or tan
θ, dφ or tanφ may be used.

When the position is designated by one finger or pen, a plurality of fingers, hands or elbows may accidentally strike the display screen 10. In such a case, it is necessary to process as erroneous detection. Therefore, in the present invention, the size information of the obstruction is obtained from the measured section length,
Based on the obtained size information, it is possible to determine what the obstacle is. FIG. 11 is a flowchart illustrating an example of an algorithm for determining the type of an obstacle. By comparing the actually calculated size information of the obstacle with the size information of a plurality of obstacles assumed in advance,
Determine the type of obstruction. When it is determined that the obstacle is other than one finger or pen, the warning flag is turned on. The size information of the plurality of assumed obstacles is stored in the ROM 2 built in the MPU 5 as described above.
5 and the RAM 26 in advance.

First, the MPU 5 acquires the current size information of the obstacle (Step S11), and determines whether or not the size is 10 cm or less (Step S12). 10c
m (NO in step S12), MP
It is determined that U5 is a hand (step S16), the warning flag is turned on (step S21), and the process returns. If it is 10 cm or less (YE in step S12)
S), the MPU 5 determines whether the size is 5 cm or less (Step S13). If it is larger than 5 cm (NO in step S13), the MPU 5 determines that the obstacle is a fist or an elbow (step S17),
The warning flag is turned on (step S21), and the process returns. If it is 5 cm or less (YE in step S13)
S), the MPU 5 determines whether or not the size is 2 cm or less (Step S14). If it is larger than 2 cm (NO in step S14), MPU 5 determines that a plurality of fingers are put together (step S18), turns on a warning flag (step S21), and the process returns.
If it is 2 cm or less (YES in step S14), MP
U5 determines whether the size is 0.5 cm or less (step S15). If it is larger than 0.5 cm (NO in step S15), the MPU 5 determines that the finger is one finger (step S19), and if it is 0.5 cm or less (YES in step S15), it uses a pen. It is determined that there is (Step S20), and the process returns.

In this manner, the type of the obstruction is determined, and when it is determined that the obstruction is other than one finger or pen for specifying the position, the warning flag is turned on and the flag information is displayed from the MPU 5. Transferred to the device 6. When the flag information is transferred, the MPU 5 sends the flag information to the display device 6.
The data of the detection position sent to the device is invalidated, and a warning mark is displayed on the screen of the display device 6. Further, a configuration in which the determined type of result is displayed on the display device 6 is also possible.

Note that a configuration may be such that a buzzer sounds when the warning flag is turned on. Further, as another method of invalidating the data of the detection position at this time, control is performed so that the data of the detection position is not output from the MPU 5 to the display device 6 when the obstacle other than one finger or pen is determined. It is also possible.

(Second Embodiment) FIG. 12 is a schematic diagram showing a basic structure of a second embodiment of the present invention, and FIG. 13 is a block diagram of the second embodiment. FIG.
2, in FIG. 13, the same reference numerals as in FIGS. 1 and 3 indicate the same members. In FIG. 12, the light emitting element driving circuits 2a and 2b and the light receiving signal detecting circuits 3a and 3
b, the polygon control circuit 4 and the display device 6 are not shown.

In the second embodiment of the apparatus of the present invention, the scanning area to be detected on the display screen 10 is
0, the optical transmission / reception unit 1a
Light-receiving elements 31a and 32a for timing detection;
The light transmitting / receiving unit 1b is provided with two light receiving elements 31b and 32b for timing detection. The light receiving surfaces of the light receiving elements 31a and 32a are located on the light transmitting / receiving unit 1a side, respectively.
Are directed toward the light transmitting / receiving unit 1b.

The light receiving elements 31a, 32
Light receiving signal detection circuits 33a, 34a, 33b, 34b for converting the light receiving amounts of the light receiving elements a, 31b, 32b into electric signals are provided. The polygon control circuit 4 according to the second embodiment includes an encoder 23 as in the first embodiment.
a and 23b, and includes a pulse motor 21 and a pulse motor drive circuit 22.

Immediately before entering the scanning area to be detected, the laser beams from the light transmitting / receiving units 1a and 1b are transmitted to the timing detecting light receiving elements 31a and 31b located on the upstream side in the scanning direction.
And immediately after exiting from the scanning area to be detected, the laser light from the light transmitting / receiving units 1a and 1b is transmitted to the timing detecting light receiving element 32 located on the downstream side in the scanning direction.
a, 32b.

As described above, in the second embodiment, the start and end timings of position detection are determined by a pair of light receiving elements, and the encoder 2 in the first embodiment is determined.
The scanning angle of the laser beam can be detected even without 3a and 23b.

FIG. 14 is a timing chart for explaining the operation of the second embodiment of the present invention. FIG. 14A shows the light emitting operation of the light emitting element 11a of the light transmitting / receiving unit 1a. FIG. 14B shows a light receiving signal of the light receiving signal detecting circuit 33a representing an amount of light received by the light receiving element 31a for timing detection located on the upstream side in the scanning direction, and FIG. FIG. 14 (d) shows the light receiving signal of the light receiving signal detection circuit 3a representing the amount of received light, and FIG.
14 (e) shows the light receiving signal of the light receiving signal detection circuit 34a representing the amount of received light, and FIG. 14 (e) shows the timing operation of a timer built in the MPU 5.

Time t0 is the timing when the power is turned on and the polygon mirror 16a starts rotating, time t1 is the timing when the light emitting operation of the light emitting element 11a is started, and time t1
Reference numeral 2 denotes a timing when the light receiving element 31a has finished receiving the laser light, and time t3 is a timing when the light receiving element 32a has started receiving the laser light. The time points t2 and t3 are the timings of the start and end of scanning, respectively. The light receiving level of the light receiving element 13a increases from the time point t2, and decreases at the time point t3. The timer starts counting at time t2 and ends counting at time t3. In addition,
The time point t4 is a timing when the light receiving level of the light receiving element 13a falls due to the blocking object (indicator), and the time point t5 is a timing when the light receiving level of the light receiving element 13a rises after the laser beam passes through the cutoff range.

The light emitting element 11a is driven while the rotation of the polygon mirror 16a is stable, and the timing at which the laser beam scanned by the light transmitting / receiving unit 1a reaches the area to be detected is determined by the light receiving timing of the light receiving element 31a (time t2). ), And the timing at which the scanning laser light exits from the region to be detected is detected as the light receiving timing (time t3) of the light receiving element 32a. The light receiving element 31a,
Since the installation position of 32a is known, the position of an obstruction (indicator) such as a finger or a pen that intercepts the scanning laser light during this time can also be measured. That is, in FIG.
Between the time point 2 and the time point t3, the interruption area and the interruption object (instruction) are determined based on the count values of the timer from the time when the light reception level of the light receiving element 13a falls (time point t4) to the time when the next light reception level rises (time point t5). The center position of the object can be measured.

The processing operation on the side of the optical transmission / reception unit 1b is the same as the processing operation on the side of the optical transmission / reception unit 1a described above, and a description thereof will be omitted.

(Third Embodiment) FIG. 15 is a diagram showing a basic configuration of a third embodiment of the device of the present invention. FIG.
In FIG. 5, the same reference numerals as in FIG. 1 denote the same members. The light emitting element driving circuits 2a and 2b, the light receiving signal detecting circuits 3a and 3b, the polygon control circuit 4, the MPU 5,
The display device 6 is not shown.

In the third embodiment, the two retroreflectors for detecting the timing of the light transmission / reception unit 1a are brought very close to the display area 10 with respect to the scanning area to be detected on the display screen 10. 41a and 42a, and two retroreflectors 41b and 42b for detecting timing with respect to the light transmitting / receiving unit 1b, respectively. These retroreflectors 41a, 42a, 41b, 42b
Is the same material as the retroreflective sheet 7.

Immediately before entering the scanning area to be detected, the laser beams from the light transmitting / receiving units 1a and 1b are applied to the timing detecting retroreflectors 41a and 41a located upstream in the scanning direction.
1b, and the reflected light is reflected by the light receiving elements 13a, 13b.
Immediately after exiting from the scanning area to be detected, the laser light from the light transmitting / receiving units 1a and 1b is reflected by the timing detecting retroreflectors 42a and 42b located on the downstream side in the scanning direction. The reflected light is received by the light receiving element 13
a, 13b.

As described above, in the third embodiment, the start and end timings of position detection are determined by a set of two retroreflectors, and the encoders 23a and 23a in the first embodiment are determined. The scanning angle of the laser beam can be detected even without 23b. In this case, since the retroreflectors 41a, 41b, 42a, and 42b are provided close to the light transmitting / receiving units 1a and 1b, the reflected light from these is reflected from the retroreflective sheet 7. The light attenuation is smaller and the light receiving level in the light receiving elements 13a and 13b is higher than in the case of FIG.

FIG. 16 is a block diagram of a third embodiment of the device of the present invention. Reference numeral 43 denotes a first signal for detecting interruption.
The comparator compares the level of the received signal from the light receiving signal detection circuit 3a indicating the amount of light received by the light receiving element 13a with the first threshold level, and outputs the comparison result to the MPU 5 as a binary signal. Reference numeral 44 denotes a second for detecting the start / end of scanning.
The comparator compares the level of the received signal from the light receiving signal detection circuit 3a with a second threshold level higher than the first threshold level, and outputs the comparison result to the MPU 5 as a binary signal.

FIG. 17 is a timing chart for explaining the operation of the third embodiment of the device according to the present invention. FIG. 17 (a) is a timing chart showing the operation of the light receiving signal detecting circuit 3a representing the amount of light received by the light receiving element 13a. 17B shows the output signal of the first comparator 43, and FIG. 17C shows the output signal of the second comparator 44. A broken line W1 indicates a first threshold level, and a broken line W2 indicates a second threshold level.

At time t0, the timing at which the reception of the reflected light from the retroreflector 41a is started, and at time t1, the reception of the reflected light from the retroreflector 41a ends, and the reflected light from the retroreflective sheet 7 ends. Timing of starting light reception, time t
Reference numeral 2 denotes a timing at which the reception of the reflected light from the retroreflective sheet 7 is completed and reception of the reflected light from the retroreflective body 42a is started, and at time t3, reception of the reflected light from the retroreflective body 42a is completed. It is timing. The time point t4 is a timing at which the light receiving level of the light receiving element 13a falls due to the blocking object (indicator), and the time point t5 is a timing at which the light receiving level of the light receiving element 13a rises after the scanning laser beam passes through the blocking range. The time point t1 and the time point t2 are the timing of the start and end of scanning, respectively. Each of these timings is detected based on a result of comparison between the level of the light receiving signal and the first threshold level W1 and the second threshold level W2.

Although the processing operation on the side of the light transmitting / receiving unit 1a has been described, the processing operation on the side of the light transmitting / receiving unit 1b is the same as the processing operation on the side of the light transmitting / receiving unit 1a. I do.

In the above-described example, the retroreflectors 41a, 41b, and 4 are set in accordance with the difference in light attenuation due to the difference in distance.
The reflected light from the retroreflective sheet 41 is distinguished from the reflected light from the retroreflective sheet 7.
By setting the reflectances of a, 42a, 41b, and 42b higher than the reflectance of the retroreflective sheet 7, it is possible to more clearly distinguish these reflected lights.

As described above, in the third embodiment of the device of the present invention, it is possible to generate a reference signal for the timing of the start and end of scanning by checking the change in the amount of light received by the light receiving elements 13a and 13b. Thus, the resolution can be kept constant without newly increasing the number of detection elements.

(Fourth Embodiment) FIG. 18A is a plan view showing a basic structure of a fourth embodiment of the device of the present invention.
FIG. 18B is a cross-sectional view taken along line AA ′ of FIG. In FIG. 18, the same reference numerals as in FIG. 1 denote the same members. In addition, the light emitting element drive circuit 2a,
2b, light receiving signal detection circuits 3a and 3b, polygon control circuit 4, MPU 5, and display device 6 are not shown.

In the fourth embodiment, an eave-shaped shield 5 is provided outside the display screen 10 so as to cover the retroreflective sheet 7.
1 is provided to a position where the field of view of the display screen 10 is not obstructed. As a result, a non-blocking area D in which a blocking object (designated object) such as a finger cannot be formed is formed between the eave-shaped shield 51 and the retroreflective sheet 7. With such a configuration, even if an obstruction (designated object) exists at any position including the peripheral portion of the display screen 10, the obstruction impossible area D
The light receiving timing of the reflected light from the scanning can be used as the reference timing of the scanning start / end.

By the way, what is indicated by reference numeral P in FIG. 18B is a cross section of the laser beam projected from the light transmitting / receiving unit 1a. As shown here,
In the present invention, the major axis of the laser beam projected from the light transmitting / receiving units 1a and 1b is flat in the direction parallel to the surface of the display screen 10 (scanning direction), for example, the direction parallel to the surface of the display screen 10. It has an elliptical cross section. The reason lies in the configuration of the retroreflective sheet 7.

FIG. 19A is a schematic diagram showing the configuration of the retroreflective sheet 7 on the reflection surface side. As shown here, the reflective surface of the retroreflective sheet 7 has a large number of spherical lenses 7.
00 are arranged in a direction parallel to the surface of the display screen 10, that is, in the scanning direction of the laser beam, and each of these spherical lenses 700 has an incident angle and a relative angle as shown in FIG. This is because, when the width of the laser beam projected from the light transmitting / receiving units 1a and 1b in the scanning direction is not larger than a certain value, an effective amount of reflected light cannot be obtained because of the relationship with the reflectance. .

However, each ball lens 7 of the retroreflective sheet 7
On the other hand, when 00 is sufficiently small, the resolution can be increased by reducing the width of the laser beam in the scanning direction. However, even in such a case, it is necessary to increase the cross-sectional area of the laser beam in order to obtain a sufficient amount of reflected light, so that the width in the direction orthogonal to the scanning method (the direction orthogonal to the surface of the display screen 10) is reduced. It is desirable to use a laser beam with an enlarged flat cross section.

FIG. 20 is a timing chart showing an example of a received signal from the light receiving signal detection circuit 3a representing the amount of light received by the light receiving element 13a in the fourth embodiment.

FIG. 20 (a) shows a received signal in the case where there is no obstacle (designated object), and FIG. 20 (b) shows a received signal when the obstacle (designated object) is not present.
Is the periphery of the display screen 10 (the area C1 in FIG. 18A).
FIG. 20 (c) is a reception signal in the case where an obstruction (designated object) exists in the center of the display screen 10 (the area C2 in FIG. 18 (a)), and FIG. 20 (d). ) Indicate received signals when an obstacle (designated object) is present at the periphery of the display screen 10 (the area C3 in FIG. 18A). Even when an obstacle (designated object) is present at the periphery of the display screen 10, it indicates that the received signal has a rising edge and a falling edge. The processing operation on the side of the light transmitting / receiving unit 1b having the light receiving element 13b is the same as that of the light transmitting / receiving unit 1 having the light receiving element 13a.
Since the processing operation is the same as that on the side a, the description thereof is omitted.

Further, by providing the eave-shaped shielding body 51 as shown in the fourth embodiment, the effect of reducing the component of the irregular reflection light from the retroreflective sheet 7 and the reflection of the disturbance light can be obtained. An effect of reducing the incidence of light on the light receiving elements 13a and 13b can also be expected.

(Fifth Embodiment) FIG. 21 is a block diagram of a fifth embodiment of the present invention. In FIG. 21, the same parts as those in FIGS. 3 and 13 are denoted by the same reference numerals, and description thereof will be omitted. AC couplings 61a and 61b are provided between the light receiving element 13a and the received signal detection circuit 3a, and between the light receiving element 13b and the received signal detection circuit 3b.
Further, XOR (exclusive OR) circuits 62a and 62b are provided between the light emitting element driving circuit 2a and the received signal detecting circuit 3a and between the light emitting element driving circuit 2b and the received signal detecting circuit 3b.

In the fifth embodiment, the light receiving element 13a,
Since the received light signal of the reflected light detected at 13b is AC-coupled, a steady light component is removed by this AC coupling, so that a configuration resistant to disturbance noise can be realized. Also,
Since the XOR (exclusive OR) of the emission pulse signal and the reception signal of the reflected light is taken, the reception pulse signal only in the cutoff range can be detected, and the pulse signal is counted to measure the cutoff time. can do.

FIG. 22 is a timing chart for explaining the operation of the fifth embodiment. FIG. 22A shows the amount of light received by the light-receiving element 31a for timing detection located on the upstream side in the scanning direction. FIG. 22 (b) is a reception signal of the light reception signal detection circuit 34a representing the amount of light received by the timing detection light receiving element 32a located on the downstream side in the scanning direction, and FIG. 22 (c) is light emission. Element 11a
FIG. 22 (d) is a light receiving signal of the light receiving signal detecting circuit 3a representing the light receiving amount of the light receiving element 13a, and FIG.
(E) represents the output signal of the XOR circuit 62a.

The timing of the start of scanning is detected in accordance with the high level of the reception signal of the light reception signal detection circuit 33a, pulse driving is started, and the number of pulses is counted. Further, the pulse drive is stopped by detecting the timing of the end of scanning according to the high level of the reception signal of the light reception signal detection circuit 34a. The cutoff range can be measured by counting the number of pulses of the output signal of the XOR circuit 62a.

For example, when the display screen 10 is equivalent to a diagonal of 40 inches, the resolution at a distance of 100 cm on the diagonal line is set to 0.1.
If it is about 5 cm, the required angular resolution is 5 mrad. Here, when a pentagonal polygon mirror is used, the scanning angle becomes 144 degrees at the maximum. Therefore, the number of divisions per scan is obtained as in the following equation (12). {(Π / 2) /0.005} × (144/90) = 502 (12) Then, the lowest frequency for performing detection at 200 points per second is obtained by the following equation (13). . 502 × 200 = 100400 (Hz) = 100.4 (kHz) (13) If this condition is satisfied, the number of pulses and the scanning angle are one-to-one.
And the angle detection process at a desired resolution can be simplified.

Next, control of pulse light emission in the light emitting elements 11a and 11b will be described. By controlling the blank time of the pulse of the drive control signal sent from the MPU 5 to the light emitting element drive circuits 2a and 2b, the average radiant energy from the light emitting elements 11a and 11b can be reduced. FIG. 23 is a timing chart showing a timing signal of pulse emission. In the example shown in FIG. 23A, the pulse blank time is longer than that in the example shown in FIG. FIG. 24 (a),
FIG. 23B shows the radiation state of the scanning laser beam in each of the pulse patterns shown in FIGS. If the blank time of the pulse emission is extended, the duty ratio decreases, and the average radiant energy can be reduced.

FIG. 25 shows a timing chart of another control example in which the average radiant energy of the pulse light emission from the light emitting elements 11a and 11b can be reduced. FIG. 25A shows a timing signal of pulse emission in a standard state. FIG.
(B) is an example in which one light emission time is reduced without changing the cycle. FIG. 25C shows an example in which the intensity of one light emission is reduced without changing the cycle.

Next, an example of control for shifting the start timing of pulse light emission in the light emitting elements 11a and 11b will be described with reference to FIG.
This will be described with reference to the timing chart of FIG. For example,
In the first laser beam scanning, scanning is performed at the timing shown in FIG. 26A, and in the next laser beam scanning, FIG.
As shown in (b), scanning is performed at the same timing but with the start timing delayed by Td from the previous timing. FIG. 27 shows a combined emission state of the scanning laser light in each of the pulse patterns of FIGS. 26 (a) and 26 (b). Since Td is temporally shifted, when the scanning angular velocity of the polygon mirror is ω, dθ = ω · Td
The scanning angle shifted only by this can be realized. By setting such a timing shift, even when the laser beam scanning is sparse, it is possible to maintain a high detection accuracy by eliminating a region in which an obstacle (indicator) cannot be detected.

Next, an example of control for dynamically changing the frequency of the scanning pulse in accordance with the presence or absence of an obstacle (indicator) will be described. Unless the presence of an obstacle (indicator) is detected within a certain time, the frequency of the scanning pulse is reduced to half while keeping the light emission time constant. On the other hand, when an obstacle (indicator) is detected, the frequency of the scanning pulse is doubled while keeping the light emission time constant. By repeating such control, the duty ratio of light emission is changed by 1/2 or 2 times at a time in accordance with the presence or absence of an obstacle (indicator). However, the minimum frequency of the scanning pulse is set to 6.25 kHz corresponding to the minimum resolution of 8 cm, and the maximum frequency is set to 200 kHz corresponding to the minimum resolution of 0.25 cm so as not to exceed these minimum and maximum frequencies.

FIG. 28 is a flowchart showing an algorithm for controlling the frequency of such a scanning pulse. First, it is determined whether or not an obstacle (indicator) has been detected within a predetermined time (step S31). If it is detected (YES in step S31), the frequency of the current scan pulse is doubled while keeping the emission time constant (step S3).
2) The process proceeds to step S34. On the other hand, when no signal is detected (NO in step S31), the frequency of the current scan pulse is reduced by half while keeping the light emission time constant (step S33), and the process proceeds to step S34. It is determined whether the frequency after the change is smaller than 6.25 kHz (step S34). If it is lower than 6.25 kHz (YES in step S34), the frequency is set to 6.25 kHz (step S36), and the routine returns. If the frequency is equal to or higher than 6.25 kHz (NO in step S34), it is determined whether the frequency after the change is higher than 200 kHz (step S35). 200 kh
If it is larger than z (YES in step S35), the frequency is set to 200 kHz (step S37), and the routine returns. If it is equal to or lower than 200 kHz (NO in step S35), the process returns.

By controlling the pulse light emission by the light emitting elements 11a and 11b as described above, the optical position detecting device of the present invention can achieve the necessary detection resolution and reduce the power consumption. it can.

By the way, although the above-mentioned embodiments have a common configuration, the two light transmitting / receiving units 1a and 1b are arranged along the short side of the display screen 10 and at a certain distance. The reasons will be described below.

In triangulation, it is generally known that the longer the reference line of the survey, the higher the accuracy. However, it is also a fact that the error is large when the survey target is extremely far, or conversely, very close. When the object to be surveyed is extremely far, the accuracy is improved by lengthening the reference line, but when the object to be measured is extremely close, the accuracy is improved by shortening the reference line. In view of the drawbacks of the triangulation, it is necessary in the apparatus of the present invention that the reference line connecting the two light transmitting and receiving units 1a and 1b be separated from the side of the display screen 10 to some extent, and that the distance of the display screen 10 or more be measured. Therefore, the two light transmitting / receiving units 1a and 1b are arranged along the short side of the display screen 10 for the purpose of improving the surveying accuracy of the near portion.

By the way, the distance d between the reference line connecting the light transmitting / receiving units 1a and 1b and one side of the display screen 10 (short side of the display screen 10 in the present invention) is to satisfy the following equation (14). Set to.

Dθ ≦ 4δd (1 / (L ² + 2δL)) (14) where dθ: measurement accuracy (beam divergence angle) δ: detection accuracy (5 mm in the apparatus of the present invention) L: reference line length ( Distance between both optical transmission and reception units)

By transforming equation (14) with respect to d, the following equation (15) is obtained.

D ≧ dθ × L ² / 4δ (15)

In the apparatus of the present invention, the detection accuracy δ is about 5 mm,
The reference line length L is about 500 mm, and the measurement accuracy dθ is determined by the AD conversion clock of the received light signal, but is about 2.5 milliradians. As a result, about 10 mm is an appropriate value for d. However, it goes without saying that this value depends on the size of the display screen 10, the divergence angle of the beam, in other words, how much measurement accuracy is required.

As described above, in the device according to the present invention, serration portions 7a and 7b are provided at portions far from the light transmitting and receiving units 1a and 1b and at which the angle of incidence of the projection light on the retroreflective sheet 7 becomes small. The reflection efficiency is improved. However, the distance from both the light transmitting / receiving units 1a and 1b to the retroreflective sheet 7 is not constant, and the above-mentioned retroreflective sheet 7 has the serrated portions 7a and 7b.
Furthermore, both light receiving elements 1
The light receiving amounts of 3a and 13b are not constant. However, it is desirable in the fifth signal processing that the amount of light received by both light receiving elements 13a and 13b is as constant as possible, and it is also preferable from the viewpoint of power consumption reduction.

From such a viewpoint, the light receiving elements 13a, 13a
A configuration for making the amount of received light input to 3b constant will be described.

FIG. 29 shows the light emitting element 11a (1b) for controlling the amount of light received by the light receiving element 13a (13b) to be constant.
It is a block diagram which shows the example of a structure which controls the light emission intensity by 1b). Specifically, the light emission intensity of the light emitting element 11a (11b) is reduced at a scanning angle where the amount of reflected light is large, and is increased at a scanning angle where the amount of reflected light is small.

In FIG. 29, the light receiving element 13a (13
The reflected light received in b) is converted into a digital signal by the received light signal detection circuit 3a (3b) and input to the MPU 5 in accordance with the light amount. The MPU 5 compares the value of the digital signal input from the light reception signal detection circuit 3a (3b) with a predetermined threshold value, and determines that the value of the digital signal input from the light reception signal detection circuit 3a (3b) exceeds the threshold value. When the value is large, the control signal CS for decreasing the light emission intensity from the light emitting element 11a (11b) is conversely applied when the value of the digital signal input from the light receiving signal detection circuit 3a (3b) is smaller than the threshold value. Outputs a control signal CS for increasing the light emission intensity from the light emitting element 11a (11b).

Control signal C output from MPU 5
Since S is of course a digital signal, it is converted into an analog drive signal DC by the current conversion circuit 51a (51b) and supplied to the stable current circuit 52a (52b) for stabilization, so that the light emitting element 11a (11b) emits light. Let it. The current conversion circuit 51a (51b) and the stable current circuit 52a
The drive circuit 50a (50b) of the light emitting element 11a (11b) is configured by (52b).

By the control by the MPU 5 as described above,
The intensity of light emission from the light emitting element 11a (11b) is constantly controlled such that the amount of light received by the light receiving element 13a (13b) becomes a predetermined value.

FIG. 30 is a block diagram showing another configuration example for controlling the light emission intensity of the light emitting elements 11a (11b). In this configuration example, the control signal CS is output from the MPU 5 to control the driving circuit 50a (50b), and the light emitting element 11a (1
Controlling the light emission intensity of 1b) is the same. However, in the above configuration example, the amount of light received by the light reception signal detection circuit 3a (3b) is monitored and feedback control is performed, whereas in this configuration example, the polygon mirror 16a (16
The light emitting element 11a (1) corresponds to the rotation angle synchronization signal AS generated by the rotation angle synchronization signal generation circuit 49a (49b) of FIG.
The emission intensity of 1b) is controlled.

More specifically, as shown in the timing chart of FIG. 31, the MPU 5 controls the rotation angle synchronizing signal AS generated by the rotation angle synchronizing signal generation circuit 49a (49b).
Is read, and the light emitting element 11a (11b)
Output a control signal CS to increase the light emission intensity at
During a period during which the scanning is performed on a portion close to the light transmitting / receiving units 1a and 1b, a control signal CS for reducing the light emission intensity of the light emitting element 11a (11b) is output. By such control by the MPU 5, the light receiving elements 13a (13b)
Light emitting element 11a so that the amount of light received by
The emission intensity from (11b) is controlled.

Instead of the configuration for controlling the emission intensity of the light emitting element 11a (11b) as described above, the light receiving element 13a (1
A configuration for amplifying the amount of received light in 3b) is also possible. FIG.
Is a block diagram showing a configuration example in such a case.

In this configuration example, the light receiving element 13a (13
The signal (analog signal) of the received light amount according to b) is converted to an amplifier 53.
a (53b) to amplify the received light signal and detect the received light signal 3a (3
b). The amplifier 53
The amplification factor of a (53b) can be controlled by supplying the control signal CS1 from the MPU 5. The MPU 5 is also supplied with a rotation angle synchronization signal AS output from the rotation angle synchronization signal generation circuit 49a (49b).

In such a configuration, MPU 5 controls rotation angle synchronizing signal AS generated by rotation angle synchronizing signal generation circuit 49a (49b), similarly to the configuration shown in FIG.
Is read, and a control signal CS1 for increasing the amplification factor in the amplifier 53a (53b) is output during a period in which an angle for scanning a portion far from the optical transmitting / receiving units 1a and 1b is closer to the optical transmitting / receiving units 1a and 1b. A control signal CS1 is output to reduce the amplification factor in the amplifier 53a (53b) during a period in which the scanning of the portion is performed. MP like this
Under the control of U5, the light receiving signal detection circuit 3a (3b)
Becomes substantially constant.

In the configuration examples shown in FIGS. 30 and 32 described above, the light emitting elements 11a (11b) are formed by using a relatively simple pattern as shown in FIG.
Although the light emission intensity or the amplification factor of the amplifier 53a (53b) is controlled, the amount of reflected light by the light receiving element 13a (13b) in the state where there is no obstacle S on the display screen 10 is monitored and the polygon mirror is controlled. The correspondence with the rotation angle of 16a (16b) is patterned and stored in advance, and thereafter, the stored pattern is compared with the actual amount of light received by the light receiving element 13a (13b) to obtain difference information. Thus, the detection of the obstacle S may be performed.

FIG. 33 is a block diagram showing an example of such a configuration. In FIG. 33, the light receiving elements 13a (13b)
Is converted into a digital signal by the light reception signal detection circuit 3a (3b). The MPU 5 stores the result of conversion by the light reception signal detection circuit 3a (3b) in the light reception amount pattern memory 54 in synchronization with the rotation angle synchronization signal AS generated by the rotation angle synchronization signal generation circuit 49a (49b). The received light amount pattern memory 54 is the RAM 2 shown in FIG.
6 may be used.

In such a configuration, digital data of the amount of light received during one scan by the light receiving element 13a (13b) is received based on the rotation angle synchronization signal AS generated by the rotation angle synchronization signal generation circuit 49a (49b). The light amount pattern is obtained and stored in the received light amount pattern memory 54. Therefore, for example, the light receiving amount pattern in a state where there is no obstacle S on the display screen 10 when the power of the apparatus of the present invention is turned on or the like is stored in the light receiving amount pattern memory 54, and the light receiving elements 13a (13b) thereafter. By detecting the difference by comparing the amount of light received at step S3 with data digitized by the light reception signal detection circuit 3a (3b), the presence of the obstacle S can be detected.

Further, it is also possible to adopt a configuration as shown in FIG. In this configuration example, as described above,
For example, the received light amount pattern in a state where there is no obstacle S on the display screen 10 when the power of the apparatus of the present invention is turned on or the like is stored in the received light amount pattern memory 54. And
The amount of light received by the subsequent light receiving element 13a (13b) is
5A (55b), the MPU 5 converts the data of the received light amount pattern stored in the received light amount pattern memory 54 into an analog signal by the A / D converter 56a (56b), and supplies the analog signal to the comparator 55a (55b). As a result, in the comparator 55a (55b), the light receiving element 13a
Light receiving signal from (13b) and light receiving amount pattern memory 54
Is compared with a signal obtained by converting the data of the received light amount pattern read out from the analog signal into an analog signal, and the difference is input to the MPU 5.

Therefore, the MPU 5 operates the comparator 55a (55
It becomes possible to detect the presence of the obstacle S according to the difference signal given from b).

Although the apparatus of the present invention has a scanning angle at which the amount of reflected light from the retroreflective sheet 7 is small as described above, the method of controlling the light emission intensity of the light emitting elements 11a and 11b as described above is employed. The solution is possible. However, the light emitting elements 11a, 11b
May not be able to increase the light emission intensity. Therefore, a case will be described below in which the light emission intensity of the light emitting elements 11a and 11b is switched between a normal state and a state in which the light emission intensity is reduced to about half thereof.

Also, as shown in FIG.
In the apparatus of the present invention, in the light transmitting / receiving unit 1a (or 1b), the laser beam projected from the light emitting element 11a (or 11b) is reflected by the polygon mirror 16a (or 16b) and directly input to the light receiving element 13a (or 13b). Timing. By utilizing this, no special means is required for detecting the start of scanning, so that the cost can be reduced.

Specifically, the direct light receiving element 13a (13
Since the scanning light incident on b) has a high light intensity, two or more comparing means having different comparison levels are prepared and the light receiving element 13a is provided.
The output of (13b) is compared, and the output of the comparison result of the comparative means at a relatively high level is used as a scanning start signal. In order to measure the time during which the scanning light is cut off, a time measuring means using a scanning start signal as a trigger for starting time measurement is provided. Alternatively, the output of the light receiving element 13a (13b) starts time measurement in accordance with the comparison result output of the comparison means of a relatively low level.

Since the fluctuation of the scanning speed causes an error,
The solution is an important issue. In order to eliminate the influence of the scanning speed fluctuation, means for measuring the interval of the scanning start signal is provided, and the error is eliminated by correcting the cutoff time of the scanning light based on the measured interval.

Hereinafter, a specific description will be given. FIG. 35 is a block diagram showing a configuration of a driving circuit 50a (50b) for the light emitting element 11a (11b). The drive circuit 50a (50b) includes a high-level driver 50H, a low-level driver 50L, and a switch 50S. MP
The ON / OFF signal is sent from U5 to both drivers 50H and 50L.
And the light emission intensity switching signal SS
S. With such a configuration, the light emitting element 11
On / off of the drive current a (11b) and two-stage switching of the light emission intensity are controlled. The configuration shown in FIG. 35 can be configured by a known circuit.

FIG. 36 is a waveform chart for explaining an example of an increase in margin (improvement of S / N) by switching light emission intensity. FIG. 36A shows the level of the received signal at the light receiving element 13a (13b) when scanning is always performed at the same light emitting intensity without switching the light emitting intensity of the light emitting elements 11a (11b). ) Indicates the light emitting element 11a (11b)
2 shows the levels of the received signals at the light receiving elements 13a (13b) when scanning is performed by switching the light emission intensity in two stages with the above configuration.

In the case shown in FIG. 36 (a) where the light emission intensity is not switched, the amount of light reflected from the retroreflector gradually decreases, and eventually increases. Here, a portion where the level is largely reduced substantially in the center is a waveform caused by the obstacle S. It should be noted here that the light receiving signal level at the light receiving element 13a (13b) is reduced by the blocking object S, but the margin M1 for the "0" level is extremely small (S / N is poor). .

On the other hand, FIG.
In the case shown in the above, although the amount of light reflected from the retroreflector gradually decreases and eventually increases,
The section indicated by L1 up to the portion where the amount of reflected light is the lowest is scanned by the low-level driver 50L, and the section indicated by H where the amount of reflected light is the lowest is by the high-level driver 50H. Scanning is performed,
In the subsequent section indicated by L2, scanning by the low-level driver 50L is performed. Therefore, if the amount of reflected light indicated by H is the lowest, but there is an obstacle S in the section where scanning by the high-level driver 50H is performed, a high light-receiving signal due to scanning by the high-level driver 50H. In the level, the level is reduced substantially as in FIG. However, it should be noted here that in FIG. 36 (b), the margin 2 with respect to the “0” level when the light receiving signal level is reduced due to the obstacle S is as shown in FIG.
6 (a) is considerably larger (S / N is good)
That is.

FIG. 37 is a block diagram showing a configuration example of the light reception signal detection circuit 3a (3b). Light receiving element 13a (13b)
Are amplified by an amplifier 57 of the light-receiving signal detection circuit 3a (3b), and then are amplified by two comparators 58H and 58H.
8L. These comparators 58H, 58
L has a different reference. The comparator 58H has a relatively high reference voltage VH, and its output is a scanning start signal SSS.
Is given to MPU5. On the other hand, the comparator 58
L has a relatively low reference voltage VL, and its output is supplied to the MPU 5 as the optical scanning cutoff detection signal SCS.

As described above and as shown in FIG. 2, in the apparatus according to the present invention, the arrangement of the light transmitting / receiving units 1a and 1b is such that the respective scanning lights are supplied to the retroreflective sheet 7 at the start of scanning.
There is a timing at which the light directly enters the own light receiving elements 13a and 13b without passing through. Accordingly, as shown in the timing chart of the light receiving signal level in FIG. 38 (a), when the polygon mirrors 16a and 16b are rotated to perform optical scanning, the scanning light is reflected by the polygon mirrors 16a and 16b and is directly transmitted to the light receiving elements 13a and 13a. The amount of reflected light when incident on 13b is approximately 80% of the amount of light projected from the light emitting elements 11a and 11b.

On the other hand, as also shown in FIG. 38 (a), when the light is once reflected by the retroreflective sheet 7 and then incident on the light receiving elements 13a and 13b, the projected light amounts are equal to the light emitting elements 11a and 11b. This is approximately 30% of the amount of light projected from. From such a point of view, the comparator 58H reference voltage VL is set to a value equal to the light amount
If the value is set between the% and 30%, the threshold value TH as shown in FIG. 38A will be set.
By detecting a portion at a level higher than the threshold value TH,
As shown in FIG. 38B, the light emitting elements 11a,
It becomes possible to obtain, as a scanning start signal, light directly reflected by the polygon mirrors 16a and 16b of the light projected from the light source 11b.

FIG. 39 is a block diagram showing a configuration example of a time setting / time measuring unit of one optical scanning cutoff time measuring system. In this example, three time measurement timers (first measurement timer 5)
9a, third measurement timer 59b, third measurement timer 59c)
And two time setting timers (a first setting timer 59d and a second setting timer 59d). The MPU 5 controls the reading of the measurement time, the time setting, and the like for each of the timers.

The scanning start signal SSS is the first measurement timer 59
a, and measures the interval time of the scanning start signal SSS. The optical scanning cutoff detection signal SCS is input to the second measurement timer 59b and the third measurement timer 59c, and measures the non-blocking time and the blocking time. The outputs of the first setting timer 59d and the second setting timer 59e are given to the drive circuit 50a (50b) as shown in FIG. 35, and become the light emission intensity switching signal SS.

FIG. 40 is a timing chart showing the time relationship with respect to the timing of one optical scan. In principle, various measurements are performed by the apparatus of the present invention using tx (x = 1, 2,...).
It is also possible to substitute x ''.

(1) Scanning start cycle (measurement: t1) In order to correct the rotation fluctuation of the polygon mirrors 16a and 16b, in other words, the motors that rotate them.
The cycle of one optical scan is measured. However, t1, t1 '
Alternatively, any one of t1 ″ may be measured. t1: L level time of the scanning start signal SSS t1 ′: Time of one cycle of the scanning start signal SSS t1 ″: Time from the start to the end of the reflection of the scanning light on the retroreflective sheet 7

(2) Position of obstruction S (measurement: t2) Time from the start of optical scanning to the position of obstruction S. However, t2
Alternatively, any one of t2 ′ may be measured. t2: Time from the start of the reflection of the scanning light on the retroreflective sheet 7 to the position of the obstacle S t2 ': Time from the scanning start signal SSS to the position of the obstacle S

(3) Width of barrier S (measurement: t3) Time of width of barrier S. t3: Time during which the scanning light is shielded by the blocking object S t3 ': Time from the start of the reflection of the scanning light by the retroreflective sheet 7 to the end of the blocking by the blocking object S t3'': From the scanning start signal SSS Time until the end of shading by the obstacle S

(4) Laser power up (output: t
4) Time from the start of scanning to the time when the power (emission intensity) of the scanning light is raised to a high level. T4: Measurement starts with the scanning start signal SSS as a trigger. Start measurement as

(5) Laser power down (output: t
5) The time from when the power (light emission intensity) of the scanning light is raised to the high level until it is lowered to the low level t5: Measurement is started with the end of t4 as a trigger t5 ': Reflection of the scanning light by the retroreflective sheet 7 Start the measurement with the start as a trigger. T5 ″: Start the measurement with the scanning start signal SSS as a trigger.

The rotation fluctuation of the polygon mirrors 16a and 16b is corrected by the following method.

(1) Time from start of scanning to detection of obstacle S t2 (t2 ') / t1 (t1' ort1 '') × k (constant)

(2) Time t3 ((t3'-t2) or (t3 "-t2 ')) / t1
(T1 'ort1'') × k (constant)

As described above, according to the apparatus of the present invention, various time information can be obtained without using any special detecting means for detecting the start of scanning. The size and the like can be obtained.

[0183]

As described above in detail, in the optical position detecting device of the present invention, the range of blocking the scanning light generated by the pointer is measured, so that the correct pointing position considering the size of the pointer is measured. The present invention has excellent effects, such as that it is possible to accurately detect, to determine the type of the pointer, and to prevent erroneous detection by an object that is not a predetermined pointer.

Further, according to the optical position detecting device of the present invention, the arrangement of the light emitting means and the light receiving means is considered so that the scanning light by the light scanning means is not blocked by the components attached to the light emitting means and the light receiving means. Therefore, the scanning light by the optical scanning means is sufficiently scanned in the scanning area direction.

Further, according to the optical position detecting device of the present invention, the arrangement of the light emitting means and the light receiving means is such that the light emitting means crosses the scanning surface of the light scanning means with the light emitting direction, and the light receiving means also has the same arrangement. Since the direction of the directivity of light reception is considered so as to intersect with the scanning surface of the optical scanning means, it is effective in reducing the size of the light transmitting and receiving means.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a basic configuration of an optical position detecting device (first embodiment) of the present invention.

FIG. 2 is a schematic diagram showing an internal configuration and an optical path of an optical transmission / reception unit.

FIG. 3 is a block diagram of an optical position detecting device (first embodiment) of the present invention.

FIG. 4 is a schematic view showing an embodiment of an optical position detecting device (first embodiment) of the present invention.

FIG. 5 is a timing chart showing a level change of a light receiving signal.

FIG. 6 is a schematic diagram showing the principle of triangulation for coordinate detection.

FIG. 7 is a schematic diagram showing a blocking object and a blocking range.

FIG. 8 is a timing chart showing a relationship between a light receiving signal, a scanning angle, and a scanning time.

FIG. 9 is a flowchart showing an algorithm for measuring a cutoff time.

FIG. 10 is a schematic diagram showing the principle of measuring the cross-sectional length.

FIG. 11 is a flowchart illustrating an algorithm for determining the type of an obstacle.

FIG. 12 is a schematic diagram showing a basic configuration of an optical position detection device (second embodiment) of the present invention.

FIG. 13 is a block diagram of an optical position detecting device (second embodiment) of the present invention.

FIG. 14 is a timing chart for explaining the operation of the optical position detecting device (second embodiment) of the present invention.

FIG. 15 is a schematic diagram showing a basic configuration of an optical position detecting device (third embodiment) of the present invention.

FIG. 16 is a block diagram of an optical position detecting device (third embodiment) of the present invention.

FIG. 17 is a timing chart for explaining the operation of the optical position detecting device (third embodiment) of the present invention.

FIG. 18 is a schematic plan view and a schematic cross-sectional view showing a basic configuration of an optical position detection device (fourth embodiment) of the present invention.

FIG. 19 is a schematic diagram showing the configuration of a retroreflective sheet and a graph showing the relationship between the incident angle and the relative reflectance.

FIG. 20 is a timing chart showing a level change of a light receiving signal.

FIG. 21 is a block diagram of an optical position detection device (fifth embodiment) of the present invention.

FIG. 22 is a timing chart for explaining the operation of the optical position detecting device (fifth embodiment) of the present invention.

FIG. 23 is a timing chart showing a timing signal of pulse emission.

FIG. 24 is a schematic diagram showing a radiation state of scanning light.

FIG. 25 is a timing chart showing a timing signal of pulse emission.

FIG. 26 is a timing chart showing a timing signal of pulse emission.

FIG. 27 is a schematic diagram showing a radiation state of scanning light.

FIG. 28 is a flowchart illustrating an algorithm of frequency control of a scanning pulse.

FIG. 29 is a block diagram showing a configuration example for controlling the amount of received light to be constant.

FIG. 30 is a block diagram illustrating a configuration example for controlling the amount of received light to be constant.

FIG. 31 is a timing chart when controlling the amount of received light to be constant.

FIG. 32 is a block diagram illustrating a configuration example for controlling the amount of received light to be constant.

FIG. 33 is a block diagram illustrating a configuration example for comparing the amount of received light with a monitoring result.

FIG. 34 is a block diagram illustrating a configuration example for comparing the amount of received light with a monitoring result.

FIG. 35 is a block diagram illustrating a configuration of a driving circuit of a light-emitting element.

FIG. 36 shows an increase in margin (S
FIG. 9 is a waveform chart for explaining an example of (/ N improvement).

FIG. 37 is a block diagram illustrating a configuration example of a light reception signal detection circuit.

FIG. 38 is a timing chart of a light receiving signal level.

FIG. 39 is a block diagram of a configuration example of a time setting / time measuring unit of the optical scanning cutoff time measuring system.

FIG. 40 is a timing chart showing a time relationship with respect to the timing of one optical scan.

FIG. 41 is a schematic plan view showing a configuration example of a light transmitting / receiving unit.

FIG. 42 is a schematic side view showing a configuration example of a light transmitting / receiving unit.

FIG. 43 is a schematic perspective view showing a configuration example of a light transmitting / receiving unit.

[Explanation of symbols]

 1a, 1b Light transmitting / receiving unit 2a, 2b Light emitting element driving circuit 3a, 3b Light receiving signal detecting circuit 4 Polygon control circuit 5 MPU 6 Display device 7 Retroreflective sheet 7a, 7b Serrated portion of retroreflective sheet 10 Display screen (coordinates) Surface) 11a, 11b Light emitting element 13a, 13b Light receiving element 16a, 16b Polygon mirror 21 Pulse motor 22 Pulse motor drive circuit 23a, 23b Encoder 24a First timer 24b Second timer 25 ROM 26 RAM 31a, 32a, 31b, 32b Light receiving element 33a, 34a, 33b, 34b Light reception signal detection circuit 41a, 42a, 41b, 42b Retroreflector 43 First comparator 44 Second comparator 51 Shield 62a, 62b XOR circuit 70 Light shielding member

Continuation of the front page (72) Inventor Iida Yasushi 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Nobuyasu Yamaguchi 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Fujitsu Limited (72) Inventor Fumitaka Abe 4-1-1 Kamikodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Fujitsu Limited

Claims (36)

[Claims] 1. An apparatus for optically detecting a position on a coordinate plane designated by a pointer, wherein: a light retroreflecting means provided outside the coordinate plane; and substantially parallel to the coordinate plane. Light scanning means for angularly scanning light in a plane, and at least two sets of light transmitting / receiving means having light receiving means for receiving light reflected by the light retroreflecting means of light scanned by the light scanning means, Measuring means for measuring a cutoff range of the scanning light on the coordinate plane formed by the pointer based on a scanning angle of the light scanning means and a light receiving result of the light receiving means. Optical position detector. 2. The display apparatus according to claim 1, wherein the coordinate plane is a quadrilateral display screen, and the light retroreflecting means substantially sets the light reflection plane to the light scanning plane outside at least three sides of the display screen. The two sets of light transmitting and receiving means are arranged outside one side of the coordinate plane where the light retroreflecting means is not arranged. The optical position detecting device as described in the above. 3. The distance d between a line segment connecting the centers of the two sets of light transmitting and receiving means and one side of the coordinate plane on which the two sets of light transmitting and receiving means are arranged is represented by the following equation: d ≧ dθ × L ² / 4δ where dθ: measurement accuracy (spreading angle of scanning light) δ: detection accuracy L: reference line length (distance between both light transmitting and receiving units) The optical position detecting device according to claim 2. 4. A part of or all of said light retroreflecting means are arranged in a sawtooth shape so as to be more perpendicular to light projected from said two sets of light transmitting / receiving means. The optical position detecting device according to claim 2. 5. The optical system according to claim 2, wherein said coordinate plane is rectangular, and said two sets of light transmitting / receiving means are arranged along one of the short sides of said coordinate plane. Position detection device. 6. The pointing device according to claim 1, further comprising a pointing position calculating unit that calculates a pointing position of the pointer using a specific point in the cutoff range measured by the measuring unit. Optical position detecting device. 7. The optical position detecting device according to claim 1, wherein information on the scanning angle is obtained from information on a scanning time of the optical scanning unit. 8. A cross-sectional length calculating means for calculating a cross-sectional length of the pointer based on the cutoff range measured by the measuring means and the designated position calculated by the designated position calculating means. Item 8. The optical position detecting device according to Item 7. 9. A size information storage unit for storing size information of a plurality of types of objects, size information of the pointer obtained from a cross-section length calculated by the cross-section length calculation unit, and the size information A comparison means for comparing size information of a plurality of types of objects stored in a storage means, and a determination means for determining a type of the indicator according to a comparison result of the comparison means. Item 10. An optical position detecting device according to item 8. 10. An invalidating means for invalidating an interruption range measured by said measuring means and an indicated position calculated by said indicated position calculating means when said judging means determines that the indicated object is other than a specific indicated object. The optical position detecting device according to claim 9, further comprising: 11. A light-emitting device, comprising: at least two light-receiving elements provided near the coordinate plane for receiving scanning light from the optical scanning means; and timing the light-receiving element to receive the scanning light with respect to the coordinate plane. 11. The optical position detecting device according to claim 1, wherein the optical position detecting device is configured to start and / or end optical scanning. 12. A reflecting means provided near the coordinate plane for reflecting scanning light from the light scanning means toward the light receiving means, wherein the reflected light from the reflecting means is received by the light receiving means. 12. The optical position detecting device according to claim 1, wherein a timing is set to a timing of starting and / or ending of optical scanning on the coordinate plane. New 13. A change in the amount of light reflected at an end of the light retroreflecting means facing one side of the coordinate plane where the light retroreflecting means is not disposed is determined by one cycle of light scanning on the coordinate plane. 12. The optical position detecting device according to claim 2, wherein the start and / or end timings are set. 14. An apparatus according to claim 1, wherein an area in which said pointer does not enter is provided between said coordinate plane around said coordinate plane and said light retroreflecting means.
2. The optical position detecting device according to claim 1. 15. The optical position detecting device according to claim 1, wherein said scanning light is pulse light, and said optical scanning means has control means for controlling pulse light emission. apparatus. 16. The optical position detecting device according to claim 15, wherein the scanning light is pulse light having a cycle sufficiently short for a required resolution. 17. The apparatus according to claim 17, wherein said control means includes means for adjusting at least one parameter among a light emission time per scan light, a light emission intensity per light, and a light emission cycle. 16. The optical position detection device according to item 15. 18. The apparatus according to claim 1, wherein said control means has means for adjusting a timing of starting optical scanning.
6. The optical position detecting device according to 5. 19. The optical position detecting device according to claim 1, wherein a cross-sectional shape of the light scanned by the optical scanning means is flat. 20. The optical position detecting device according to claim 1, wherein a cross-sectional shape of the light scanned by the optical scanning means is flat in a direction parallel to the coordinate plane. 21. The light-receiving device according to claim 1, further comprising a light-shielding member for preventing light scanned by one of the two light-transmitting / receiving means from being incident on the other light-receiving means. Optical position detecting device. 22. The optical position detecting device according to claim 1, further comprising a light receiving amount control unit that controls a light receiving amount of each of the two sets of light transmitting and receiving units to be constant. 23. The apparatus according to claim 22, wherein the light receiving amount control means controls the intensity of light scanned by the light scanning means so as to keep the light receiving amount of the light receiving means constant. 4. The optical position detecting device according to claim 1. 24. The apparatus according to claim 22, wherein said light receiving amount control means controls an amplification factor of a level of a light receiving signal of said light receiving means so as to keep a light receiving amount by said light receiving means constant. 4. The optical position detecting device according to claim 1. 25. A storage means for storing information on the amount of light received by the light receiving means of each of the two sets of light transmitting / receiving means in an initial state, and information on the amount of light received and the amount of light received by the light receiving means. 3. The optical position detecting device according to claim 1, further comprising: comparing means for comparing the two. 26. A storage means for storing information of the amount of light received by the light receiving means of each of the two sets of light transmitting / receiving means in an initial state as a digital signal, and a converter for converting the digital signal stored in the storage means into an analog signal. 3. The optical position detecting device according to claim 1, further comprising: means for comparing the amount of light received by the light receiving means with an analog signal converted by the converting means. 27. Switching means for switching the intensity of light scanned by said optical scanning means in at least two stages, wherein said switching means is controlled in accordance with a scanning angle of light scanned by said optical scanning means. The optical position detecting device according to claim 1, wherein: 28. The light scanning means is configured so that light scanned by the light scanning means is directly incident on the light receiving means without passing through the retroreflecting means at the start of scanning, and a light receiving amount signal from the light receiving means is compared. A first comparing means for comparing with a first reference value having a relatively large value; and a second comparing means for comparing with a second reference value having a relatively small value. 3. The optical position detecting device according to claim 1, wherein the optical position detecting device is set to start scanning. 29. At least two or more time measuring means, wherein a timing of scanning start, which is a comparison result output by the first comparing means, is used as an activation trigger of the time measuring means, and the time measuring means measures a predetermined time. 29. The optical position detecting device according to claim 28, wherein said switching means is switched at a point in time. 30. At least four timing means using a start timing of scanning, which is a comparison result output by the first comparing means, as a start trigger, and a timing at which the output of the second comparing means changes from true to false. Wherein two of the four time-measuring means are stopped, and the other two time-measuring means are stopped at a timing when the output of the second comparing means changes from false to true. The optical position detecting device according to claim 28, wherein 31. Four timing means having a timing at which the output of said second comparing means changes from false to true as a start trigger, wherein at the timing when the output of said second comparing means is converted from true to false. Two of the four time-measuring means are stopped, and the other two time-measuring means are stopped at a timing when the output of the second comparing means changes from false to true. The optical position detecting device according to claim 28. 32. At least two timing means for timing an interval of a scan start timing which is a comparison result output by said first comparing means, and a timing result by said four timing means is obtained by said at least two timing means. 31. The apparatus according to claim 30, wherein the correction is performed based on a time measurement result.
32. The optical position detecting device according to any one of the above items. 33. An apparatus for touching a display screen of a flat display with an indicator and optically detecting a touched position, wherein light retroreflecting means arranged outside three sides of the display screen; Light scanning means arranged outside one side of the screen where the light retroreflecting means is not arranged, and angularly scanning light in a plane substantially parallel to the display screen; and the light scanning means At least two sets of light transmitting / receiving means having light receiving means for receiving light reflected by the light retroreflecting means of light scanned by the light scanning means, based on a scanning angle of the light scanning means and a light receiving result of the light receiving means An optical position detecting device, comprising: a measuring unit configured to measure a blocking range of scanning light on the display screen formed by the indicator. 34. The optical position detecting device according to claim 33, wherein the flat display is a plasma display. 35. An apparatus for optically detecting a position on a coordinate plane designated by an indicator, a light retroreflecting means provided outside the coordinate plane, a light emitting means, and the light emitting means emits light. Light scanning means for angularly scanning light in a plane substantially parallel to the coordinate plane; and light receiving means for receiving light reflected by the light retroreflecting means on light scanned by the light scanning means. And at least two sets of light transmitting / receiving means each having a means, based on a scanning angle at the light scanning means and a light receiving result at the light receiving means, a scanning light on the coordinate plane formed by the pointer. Measuring means for measuring a cutoff range, wherein the light emitting means is arranged so that an optical axis of light emitted by the light intersecting with a scanning surface of light by the light scanning means, the light receiving means , The direction of the directivity of the light it receives Optical position detection apparatus characterized by being arranged to intersect the scanning surface of the light by the optical scanning unit. 36. An apparatus for optically detecting a position on a coordinate plane designated by an indicator, a light retroreflecting means provided outside the coordinate plane, a light emitting means, and the light emitting means emits light. Light scanning means for angularly scanning light in a plane substantially parallel to the coordinate plane; and light receiving means for receiving light reflected by the light retroreflecting means of light scanned by the light scanning means. And at least two sets of light transmitting and receiving means each having a means, based on a scanning angle by the light scanning means and a light receiving result by the light receiving means, a scanning light on the coordinate plane formed by the pointer. Measuring means for measuring a cutoff range, wherein the light emitting means is arranged so that a path of light emitted by the light emitting means to the light scanning means is away from an edge of the coordinate plane in a portion close to the light emitting means side. Said light receiving means, Optical position detection apparatus and a direction of directivity of light to be received is arranged away from the edge of the coordinate plane in a portion closer to the light receiving unit side.