JPH1185376A - Information display device with optical position detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make easily maintainable the matching between two coordinate systems by comparing the position of an indication body detected on the basis of a 2nd coordinate system with a specific position of a 1st coordinate system and correcting it. SOLUTION: Laser lights emitted by light emitting elements 11a and 11b angularly scan a plane substantially parallel to a display screen 10 through the rotation of polygon mirrors 16a and 16b and are projected on a retroreflective sheet 7 and their reflected lights are reflected by the polygon mirrors 16a and 16b and then made incident on light receiving elements 13a and 13b. If there is a shield body in the optical paths of the projection lights, the reflected lights are not made incident on the light receiving elements 13a and 13b. The coordinate axis of the 2nd coordinates of an indication body detecting device and the coordinate axis of the 1st coordinate system of the display screen 10 possibly shift from each other because of a position shift error between the retroreflective sheet 7 and light transmission/reception units 1a and 1b, so the both need to be corrected while made to correspond to each other and conversion between the unit systems of the both is necessary and carried out by using a linear conversion expression.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device on which information is displayed by a computer system or the like, and a display device for optically detecting a pointing position on the display screen by a pointer detecting device and displaying the detection result. The present invention relates to an information display device with an optical position detecting device, which is displayed directly on a display screen of the display device or on a display screen superimposed on the display screen of the display device.

[0002]

2. Description of the Related Art With the spread of computer systems such as personal computers, new information is obtained by pointing a display screen of a display device on which information is displayed by the computer system with a human finger or a specific indicator. For example, a device for inputting a password or giving various instructions to a computer system is used.

When an input operation is performed on information displayed on a display screen of a display device such as a personal computer by a touch method, a contact position (pointed position) on the display screen is accurately determined. Need to be detected. As a method of detecting a pointed position on a display screen serving as such a coordinate plane, a "Carroll method" (U.S. Pat.
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, a high S / N can be obtained and the application to a large display device can be extended. However, since the detection resolution is proportional to the arrangement interval of the light emitting element and the light receiving element, the detection resolution is increased. Therefore, it is necessary to narrow the arrangement interval. 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.

[0004] 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.

[0005] Still another optical position detecting method has been proposed in Japanese Patent Application Laid-Open No. Sho 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.

[0006]

However, in either method, if the coordinate system used as a reference for the display screen of the display device does not match the coordinate system used as a reference for the detection by the pointer detection device. Obviously, it is not practical. Needless to say, both coordinate systems need to be adjusted so as to coincide with each other at the time of manufacture of the device, but need to be constantly adjusted even during use.

The present invention has been made in view of such circumstances, and it is easy to match a coordinate system used as a reference for a display screen of a display device with a coordinate system used as a reference for detection by an indicator detecting device. It is an object of the present invention to provide an information display device with an optical position detecting device that can be maintained.

[0008]

According to a first aspect of the present invention, there is provided an information display device with an optical position detecting device, which displays information on a display screen based on a first coordinate system, and is arranged around the display screen. Information with an optical position detecting device, comprising: an indicator detecting device for optically detecting the position indicated by the indicator in a predetermined area on the display screen and the size of the indicator with reference to the second coordinate system. A display device, wherein the display device has an indication reference position display means for displaying an indication reference position at a predetermined position in a first coordinate system on a display screen. When the pointer is located, the designated position of the pointing object detected with reference to the second coordinate system is compared with a predetermined position in the first coordinate system, so that the first coordinate system and the second coordinate system are compared.
And a correction means for making the coordinate system coincide with the coordinate system.

According to a second aspect of the present invention, there is provided the information display device with the optical position detecting device according to the first aspect, wherein the pointer detecting device is provided with light retroreflecting means provided outside a predetermined area, and substantially parallel to the area. At least two sets of light transmitting / receiving means having light scanning means for angularly scanning light in a certain plane, and light receiving means for receiving light reflected by light retroreflecting means on a portion irradiated by light, and light scanning means Measuring means for measuring a range of cutoff of scanning light in an area formed by the indicator based on the scanning angle at and the light receiving result at the light receiving means, and the position of the indicator based on the measurement result by the measuring means And calculating means for calculating the size.

According to a third aspect of the present invention, there is provided the information display device with the optical position detecting device according to the first or second aspect, wherein the correcting means starts displaying from the designated position detected by the designated object detecting device with reference to the second coordinate system. When calculating the display position on the display screen of the apparatus with reference to the first coordinate system, the display position is corrected using a linear conversion equation.

According to a fourth aspect of the present invention, in the information display device with the optical position detecting device according to any one of the first to third aspects, the pointing reference position display means sets the pointing reference position differently within a predetermined area on the display screen. It is characterized in that at least three points are set.

According to a fifth aspect of the present invention, in the information display device with the optical position detecting device according to any one of the first to third aspects, the pointing object detecting device is configured to detect the pointing object a plurality of times. Features.

According to a sixth aspect of the present invention, in the information display device with the optical position detecting device according to the third aspect, the correction means uses a statistical method when determining the correction coefficient of the primary conversion type. Features.

According to a seventh aspect of the present invention, in the information display device with the optical position detecting device according to the third or sixth aspect, the correction means detects the size of the pointer detected by the pointer detector based on the second coordinate system. A correction coefficient used for calculating a display area of a display object based on the first coordinate system on the display screen of the display device based on the first conversion formula. And

An information display device with an optical position detecting device according to claim 8 is the device according to claim 3, 6 or 7,
The correction unit calculates a display area of the display object based on the first coordinate system on the display screen of the display device from a size of the pointer detected by the pointer detection device based on the second coordinate system. The correction coefficient used at this time is characterized by using the maximum value or the minimum value of a plurality of specific coefficients among the correction coefficients of the primary conversion equation.

According to a ninth aspect of the present invention, there is provided the information display device with the optical position detecting device according to any one of the third, sixth and seventh aspects.
The correction unit calculates a display area of the display object based on the first coordinate system on the display screen of the display device from a size of the pointer detected by the pointer detection device based on the second coordinate system. The correction coefficient used at this time is characterized in that an average value of a plurality of specific coefficients among the correction coefficients of the primary conversion equation is used.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings showing the embodiments.

FIG. 1 is a schematic diagram showing a basic configuration of an information display device with an optical position detecting device according to the present invention (hereinafter, referred to as the present device).

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 apparatus 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.

Reference numeral S indicates a cross section of a human finger as a blocking object (pointing object).

The two light transmitting / receiving units 1a and 1b are each composed of a light emitting element 11 composed of a laser diode for emitting an infrared laser.
a, 11b, light receiving elements 13a, 13b for receiving light reflected from the retroreflective sheet 7, and light emitting elements 11a, 11b.
In the present embodiment for angularly scanning the laser beam from b, the quadrangular polygon mirrors 16a and 16b and the like are main components. The light receiving elements 13a and 13b function as light receiving means, and the light emitting elements 11a and 11b and the polygon mirrors 16a and 16b function as light scanning means. The two sets of light transmitting / receiving units 1a and 1b, their signal processing systems, the retroreflective sheet 7, and the like function as measuring means.

In such a configuration, the light emitting element 11
a, 11b is angularly scanned in a plane substantially parallel to the display screen 10 by the rotation of the polygon mirrors 16a, 16b, and the retroreflective sheet 7 is rotated.
Is projected to Then, the reflected light from the retroreflective sheet 7 is reflected by the polygon mirrors 16a and 16b, and then enters the light receiving elements 13a and 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 polygon mirror 16a,
By the rotation of 16b, angular scanning of laser light of 90 degrees or more is realized.

Reference numeral 5 denotes an MPU for measuring and calculating the position and size of an obstruction (indicator) S such as a finger or a pen, and for controlling the operation of the entire apparatus. A calculation unit 51 that calculates the position and size of the pointer S from the measurement result of the calculation unit 51, and an image control unit 52 that controls information to be displayed on the display device 6 based on the calculation result by the calculation unit 51. . The display device 6 is shown in FIG.
Although they are shown independently, the display screen 10 is also used in practice.

In such an apparatus of the present invention, as shown in FIG. 1, for example, with respect to the light transmitting / receiving unit 1b, the projected light from the light transmitting / receiving unit 1b is:
In FIG. 1, the scanning is performed in the counterclockwise direction, and the scanning is started at a position (Ps) where the light is first reflected at the leading end of the retroreflective sheet 7. 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, light is scanned 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.

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.

Next, the operation of detecting the position on the coordinate plane by the apparatus of the present invention will be described with reference to the schematic diagram of FIG. However, in FIG. 2, the light transmitting / receiving units 1a, 1
b, constituent members other than the retroreflective sheet 7 and the display screen 10 are not shown. In the following description, the light transmitting / receiving unit 1b side is referred to as channel 1 (Ch1), and the light transmitting / receiving unit 1a side is referred to as channel 2 (Ch2).

By controlling the polygon control circuit, the MPU 5 rotates the polygon mirrors 16a and 16b in the light transmitting and receiving units 1a and 1b, thereby turning on the light emitting elements 11a and 11b.
The laser beam from b is scanned angularly. As a result, the reflected light from the retroreflective sheet 7 enters the light receiving elements 13a and 13b. In this way, the amount of light received on the light receiving elements 13a and 13b is obtained as a light receiving signal which is an output of a signal processing circuit (not shown). The change in the level of the received light signal is detected as a scanning angle by both optical scanning means 12a and 12b, and is processed by the following method.

The information provided to the calculation unit 51 of the MPU 5 is mainly the following four types of information shown in FIG.

Θ _1-1 : Angle from the start of scanning of Ch1 (light transmission / reception unit 1b) to detection of pointer S θ _1-2 : Detection width angle of pointer S of Ch1 (light transmission / reception unit 1b) θ _2-1 : Angle from the start of scanning of Ch2 (light transmission / reception unit 1a) to detection of indicator S θ _2-2 : Detection width angle of indicator S of Ch2 (light transmission / reception unit 1a)

The calculation of the coordinates P to be obtained (the center of the pointer S) and the calculation of the radius r of the pointer S are performed by the following equations (1) to (6). However, both light transmitting and receiving units 1a,
When 1b is installed along the short side on the left side in FIG. 1, equations (4) to (6) are expressed by equations (4 '), (5'), and (6 '), respectively. Become.

Θ ₁ = θ _1-1 + θ _1-2 / 2 (1) θ ₂ = θ _2-1 + θ _2-2 / 2 (2) y = L × tan θ ₁ / (tan θ) ₁ + tan θ ₂ ) (3) x = W−y × tan θ ₂ (4) r1 = {(W−x) ² + y ² ｝ ^1/2 × sin (θ _2-2 / 2) ... (5) or r2 = {(W-x) ² + (L-y) ² } ^1/2 × sin (θ _1-2 / 2) ・ ・ ・ (6) x = y × tan θ ₂ · .. (4 ′) r1 = (x ² + y ² ) ^1/2 × sin (θ _2-2 / 2) (5 ′) or r2 = (x ² + (L−y) ² ) ^{1 / 2} × sin (θ _1-2 / 2) (6 ')

FIG. 3 shows a superposition of a coordinate system (second coordinate system) used as a detection reference by the pointer detection device and a coordinate system (first coordinate system) used as a reference for display on the display screen 10. It is a schematic diagram which shows the relationship between a state and the coordinate axis of both coordinate systems.

In the apparatus according to the present invention, the retroreflective sheet 7 of the pointing object detecting device and the light transmitting / receiving units 1a and 1b are provided around the display screen 10. Due to these positional deviation errors and the like, the second coordinate system (x, y) (unit:
mm) and the first coordinate system (X,
Y) (the unit: dot) and the coordinate axis may be shifted. For this reason, if both are not correlated and corrected, an image may be displayed at a position different from the position indicated by the pointer S. In addition, since the coordinate unit of the pointing object detection device is an absolute length (mm), whereas the coordinate unit of the display screen 10 is a pixel (dot), it is necessary to convert the unit system between the two.

Under such circumstances, the apparatus of the present invention performs the above-described coordinate transformation using a linear transformation equation as shown in the following equation (7).

[0038]

(Equation 1)

Here, the coefficients m _{0 to} m ₅ in the equation (7) are determined by displaying a marker indicating a designated reference position whose coordinates are known on the display screen 10, and using the marker with the pointer S. It is determined by calculating from the relationship with the detection position at the time of instructing.

The coefficient in the equation (7) is 6 of m _{0 to} m ₅ .
In order to obtain these, Equation (7) is
It is sufficient to perform the same instruction operation and detection as described above, once at each of three different positions.
However, in order to further increase the calculation accuracy, it is desirable to set more indication reference positions to display the markers, and to perform the detection operation with each marker a plurality of times.

In the example shown in FIG. 3, markers are displayed at the following four positions, and the detection process is performed ten times each.

Mark 1: (X1, Y1) = (100, 100) Mark 2: (X2, Y2) = (500, 100) Mark 3: (X3, Y3) = (500, 300) Mark 4: (X4, Y4) = (300, 100)

Further, in order to determine the coefficients m _{0 to} m ₅ in the equation (7) with higher accuracy, the number of markers and the number of detections at each marker are increased, and statistical processing such as the least squares method is used. It is desirable.

More specifically, 40 data (x _{n, i} , y _{n, i} ) obtained from the detection processing of the indicator S indicating the marker
(Where n = 1 to 4, i = 1 to 10), the coefficients m _{0 to} m ₅ of the equation (7) are obtained using the least squares method. That is, when the function f is set as in the following equation (8), the following equation (9) is obtained by setting all the equations partially differentiated by the variables m _{0 to} m ₅ to be obtained as “0”. The coefficients m _{0 to} m ₅ are obtained by solving the simultaneous equations.

[0045]

(Equation 2)

[0046]

(Equation 3)

Thereafter, when detecting the position of the pointer S, the coordinates of the second coordinate system, which is the reference of the position detection of the pointer detecting device, are used as a reference for display on the display screen 10 according to the equation (7). The coordinate conversion is performed to coordinate values in the first coordinate system.

The above is a method of converting the coordinate values relating to the position of the pointer S. The same conversion is required for the size of the pointer S. Ordinarily, an orthogonal coordinate system such as that performed by the apparatus of the present invention is required. The coordinate conversion between the two can be divided into three procedures: parallel movement of the coordinate origin, rotation of the coordinate axes, and enlargement of the coordinates. Therefore, the above equation (7) can be rewritten as the following equation (10).

[0049]

(Equation 4)

Two points (x1,
The distance r (mm) of (y1)-(x2, y2) is set to two points (X1, Y1)-(X2, Y) on the coordinate system of the corresponding display screen 10.
When converted into the distance R (dot) of 2), the following equation (11) is obtained.
become that way.

[0051]

(Equation 5)

Normally, both the second coordinate system of the pointer detecting means and the first coordinate system of the display screen 10 often have a 1: 1 memory interval ratio on the xy axes. Therefore, usually a1 = a
In order to set to 2, the above equation (11) can be simplified as the following equation (12).

[0053] ^{R 2 = (r1 2 a1 2} + r2 2 a2 2) {(x1-x2) 2 + (y1-y2) 2} = (m0 2 + m1 2) r 2 = (m2 2 + m3 2) r 2 ·・ ・ (12)

Therefore, according to the above equation (12), the size r of the pointer S in the second coordinate system of the pointer detection means (unit:
mm) is converted into the size R (unit: dot) of the pointer S in the first coordinate system on the display screen 10.

If the mounting error between the pointer detecting means and the display screen 10 is extremely small and the element of the rotational displacement of the coordinate axes is extremely small and can be ignored, then m0 >> m1, m2 << m3. In this case, the above equation (12) can be further simplified to the following equation (13).

[0056]

(Equation 6)

As described above, when calculating R, one of m0 and m3 may be selected and used. However, it is also possible to select either one of m0 and m3, whichever is greater, or the smaller one, or obtain an average value of both and use it.

[0058]

As described in detail above, according to the present invention,
The coordinate system used as a reference for the display screen of the display device and the coordinate system used as a reference for the detection by the pointer detection device are made to coincide with each other as needed during the manufacture of the device as well as during use. Adjustment is easily possible.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a basic configuration of a device of the present invention.

FIG. 2 is a schematic diagram showing the principle of a position detecting operation on a coordinate plane by the device of the present invention.

FIG. 3 is a schematic diagram showing a state of superposition of a first coordinate system and a second coordinate system and a relationship between coordinate axes of both coordinate systems.

[Explanation of symbols]

 1a, 1b Optical transmission / reception unit 5 MPU 6 Display device 7 Retroreflective sheet 10 Display screen 11a, 11b Light emitting element 13a, 13b Light receiving element 16a, 16b Polygon mirror 51 Calculator 52 Image controller

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fumihiko Nakazawa 4-1-1, Kamidadanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Inside Fujitsu Limited (72) Inventor Yasushi Iida 4 Kamikadanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited (72) Inventor Fumitaka Abe 4-1-1 Kamikadanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture Fujitsu Limited

Claims (9)

[Claims] 1. A display device for displaying information on a display screen on the basis of a first coordinate system, a position arranged around the display screen and a position indicated by a pointer in a predetermined area on the display screen and the pointer. And an indicator detecting device that optically detects the size of the first coordinate system with reference to a second coordinate system. The information display device with the optical position detecting device, wherein the display device is configured to display the first coordinate system on a display screen. Pointing reference position display means for displaying a pointing reference position at a predetermined position, wherein the pointing device detection device detects the pointing device based on the second coordinate system when the pointing device is positioned on the display screen. A correction unit that compares the first coordinate system with the second coordinate system by comparing the designated position of the pointer with a predetermined position in the first coordinate system. Information display device with optical position detector 2. An indicator detecting device, comprising: a light retroreflecting means provided outside the predetermined area; an optical scanning means for angularly scanning light in a plane substantially parallel to the area; And at least two sets of light transmitting and receiving means having light receiving means for receiving light reflected by the light retroreflecting part of a portion irradiated by light; and a scanning angle by the light scanning means and a light receiving result by the light receiving means. Measuring means for measuring a blocking range of the scanning light in the area formed by the pointer, and calculating means for calculating the position and size of the pointer based on the measurement result by the measuring means. The information display device with an optical position detection device according to claim 1, comprising: 3. The correction means based on the first coordinate system on a display screen of the display device from a designated position detected by the designated object detection device based on the second coordinate system. The information display device with an optical position detection device according to claim 1 or 2, wherein when calculating the display position, the display position is corrected using a linear conversion equation. 4. The pointing reference position display means is adapted to set the pointing reference position to at least three different points within a predetermined area on the display screen. 3. The information display device with an optical position detection device according to any one of 3. 5. The optical position detecting device according to claim 1, wherein the pointing device is configured to detect the pointing device a plurality of times. Information display device. 6. The information with an optical position detecting device according to claim 3, wherein the correction means uses a statistical method when determining the correction coefficient of the primary conversion equation. Display device. 7. The method according to claim 1, wherein the correction unit uses the first coordinate system on the display screen of the display device based on a size of the pointer detected by the pointer detection device based on the second coordinate system. 7. A correction coefficient used when calculating a display area of a display object, wherein the correction coefficient is determined based on the correction coefficient of the primary conversion equation.
An information display device with an optical position detecting device according to item 1. 8. The method according to claim 1, wherein the correction unit is configured to determine the size of the pointer detected by the pointer detection device based on the second coordinate system with reference to the first coordinate system on the display screen of the display device. The correction coefficient used when calculating the display area of the displayed object is set to use the maximum value or the minimum value of a plurality of specific coefficients among the correction coefficients of the linear conversion formula. Item 8. An information display device with an optical position detecting device according to any one of Items 3, 6, and 7. 9. The method according to claim 1, wherein the correction unit uses the first coordinate system on the display screen of the display device based on a size of the pointer detected by the pointer detection device based on the second coordinate system. The correction coefficient used when calculating the display area of the displayed object, wherein an average value of a plurality of specific coefficients among the correction coefficients of the linear conversion formula is used. 8. The information display device with an optical position detection device according to any one of 6 and 7.