JP2003276399A - Position detecting method and device, and electronic blackboard device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To accurately detect the position of an electronic pen on an electronic blackboard. SOLUTION: A screen 105 having optical transparency,
An electronic pen 107 that emits light of a predetermined wavelength while moving on the screen 105, and an infrared ray that receives light emitted from the electronic pen 107 and transmitted to the rear side of the screen 105 to detect the position of the electronic pen 107 Camera 106
And a configuration having:

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is combined with a display device for projecting and displaying image information on the screen surface from the back side on the observation side, and a position detecting method and device for an electronic pen and an electronic blackboard for drawing information on the screen surface. It relates to the device.

[0002]

2. Description of the Related Art In recent years, personal computers and projectors have become widespread, and in electronic blackboards used for meetings and the like, interactive boards have been developed that can be additionally written on personal computer data during a meeting or that can contain written data in the personal computer.

In the interactive board, a data projector using liquid crystal or the like is used for display, and an electronic pen using ultrasonic waves or the like is used as a writing pen. It is designed to detect Hereinafter, such a board is referred to as an interactive electronic blackboard.

A conventional interactive electronic blackboard will be described below.

FIG. 7 is a schematic view showing a state of using a conventional interactive electronic blackboard device.

[0006] This electronic blackboard has casters for movement on its legs, and can be pushed to a place where it is used such as a conference room by hand, so that it can stand by itself without the need for supporting or fixing walls. It is a mobile interactive electronic blackboard.

In the illustrated interactive electronic blackboard, a control unit 202 and a writing surface 203 are attached to a frame body 201.

Here, the writing surface 203 is sequentially used by rotating the belt-shaped writing surface 203 in the right or left direction and automatically stopping at a plurality of preset positions. It has a structure that allows it. Writing on the writing surface 203 is performed with, for example, a felt pen. Note that one writing surface 203 may be used instead of the plurality of writing surfaces 203.

Further, the control unit 202 is equipped with a thermal printer or the like for copying the image described on the writing surface 203, a power switch for driving the electronic blackboard, a copying switch for operating the printer, and the above-mentioned description. A feed switch and the like for the surface 203 are provided.

The electronic blackboard is provided with an electronic pen 207 having an ultrasonic oscillator and an infrared ray emitting section. The electronic pen 207 has a structure in which when the pen tip is pressed against the writing surface 203, the switch is turned on and infrared rays and ultrasonic waves are emitted.

On the left and right of the upper part of the writing surface 203,
A reception unit 205 and a reception unit 206 for ultrasonic waves and infrared rays emitted from the electronic pen 207 are arranged vertically and horizontally.

A caster mechanism 204 is attached to the leg portion of the frame body 201 to move the self-standing electronic blackboard so that the electronic blackboard can be installed at an arbitrary position in a meeting place or the like.

An electronic pen 207 is provided on such an electronic blackboard.
A personal computer 209 that captures the locus of the character as character data, and the character data captured by the personal computer 209 on the surface 203.
A projection unit 208 for projecting and displaying as a character is connected to the position described by the electronic pen 207 in FIG.

Such an electronic blackboard is set up at a desired place of use, and the person in charge advances a meeting while writing on the writing surface 203 with a felt pen. If an unnecessary part is generated, it can be erased with a dedicated eraser.

Then, the feed switch provided in the control unit 202 is operated to send the film, which is the writing surface 203, to the right or left to set a new writing surface 203, write a new writing surface 203, and continue the conference. It is possible to

When the copy switch in the control unit 202 is pressed, the content on the writing surface 202 is electrically read by an image sensor or the like, and the content written on the writing surface 202 is reduced and copied by the printer.

By using the electronic blackboard in this way, it is possible to effectively proceed with the conference and to make a copy of the materials such as the minutes.

When the interactive electronic blackboard is used, the projection unit 208 and the personal computer 209 are used in addition to the electronic blackboard.

That is, when the infrared ray and the ultrasonic wave emitted from the electronic pen 207 are received by the two receiving sections 205 and 206, the receiving sections 205 and 206 and the electronic pen 207 are separated by the propagation time difference between the infrared ray and the ultrasonic wave. The distance between them is obtained, and the position of the electronic pen 207, that is, the locus is detected. The detected locus of the electronic pen 207 is taken into the personal computer 209 as character data to be described data. Then, the data taken in by the personal computer 209 is projected and displayed as characters on the writing surface 203 at the writing position of the electronic pen 207 through the projection unit 208.

When the interactive electronic blackboard is used in this way, the contents described can be taken in as electronic data,
Alternatively, it is possible to electrically transmit to a distant place through a network or the like, and it is possible to improve the efficiency of the conference and the efficiency of information transmission.

[0021]

However, in the conventional interactive electronic blackboard, when ultrasonic waves are used to detect the position of the electronic pen (object to be detected), the speed of sound changes depending on the temperature and humidity of the environment in which it is used. Therefore, there is a possibility that the accuracy may be deteriorated or that the accuracy may be deteriorated due to the reflection in the installation environment and the housing.

Further, in the case where the front projection unit is used to display the position of the electronic pen, a shadow is generated, which causes a decrease in the accuracy of position detection.

Therefore, it is an object of the present invention to provide a position detecting method and device and an electronic blackboard device which can accurately detect the position of the object to be detected.

[0024]

In order to solve this problem, the position detecting method of the present invention is to detect the position of an object to be moved which moves on a screen portion having a light scattering transmission from the object to be detected. The light of a predetermined wavelength that is transmitted to the back side of the screen portion is received and detected.

In order to solve this problem, the position detecting device of the present invention comprises a screen portion having a light-scattering / transmitting property, an object to be detected which emits light of a predetermined wavelength while moving on the screen portion, and an object to be detected. An optical position detecting means for detecting the position of the object to be detected by receiving the light emitted from the body and transmitted to the back surface side of the screen portion.

According to this, since the infrared rays emitted from the detection object moving on the screen portion are transmitted to the back side of the screen portion and received to detect the position, the position of the detection object can be accurately determined. Can be detected.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION According to the first aspect of the present invention, the position of an object to be detected which moves on the screen portion having light-scattering / transmissive property is set at the rear surface of the screen portion when light is emitted from the object to be detected. It is a position detection method that receives and detects light of a predetermined wavelength that is transmitted to the side, and the infrared rays emitted from the detection target moving on the screen are transmitted to the back side of the screen to be received and the position is determined. Since the detection is performed, the position of the detection target can be accurately detected.

According to a second aspect of the present invention, a screen portion having a light-scattering / transmitting property, a detection object that emits light of a predetermined wavelength while moving on the screen portion, and the detection object emits light. Is a position detecting device having an optical position detecting means for detecting the position of the object to be detected by receiving the light transmitted to the back side of the screen part, and is emitted from the object to be detected moving on the screen part. Since infrared rays are transmitted to the back side of the screen portion and received by the optical position detecting means to detect the position, the position of the object to be detected can be accurately detected.

According to a third aspect of the present invention, in the second aspect of the invention, the optical position detecting means is a CCD.
The position detection device is provided with an area sensor having the following structure, and has an effect that it is possible to perform highly accurate position detection with high detection sensitivity.

The invention according to claim 4 of the present invention is the position detecting device according to claim 2 or 3, wherein the light emitted from the object to be detected is infrared rays, and the projected image of visible light and detection are performed. This has the effect of reliably separating the signal.

According to a fifth aspect of the present invention, in the invention according to the fourth aspect, visible light is attenuated and infrared rays are transmitted along an optical path between the optical position detecting means and the screen portion. This is a position detection device in which a filter is arranged, and has an effect of reliably separating a projected image of visible light and a detection signal.

According to a sixth aspect of the present invention, in the invention according to any one of the second to fifth aspects, the object to be detected is when the tip is pressed against the screen portion or the object to be detected. It is a position detection device that emits light when a switch provided in is pressed, and since only the part that should be displayed on the screen part emits light and it is separated from the mere moving state of the detected object, This has the effect that the light emission position of can be used as the trajectory data.

According to a seventh aspect of the present invention, in the invention according to any one of the second to sixth aspects, the light emitted from the object to be detected has a specific emission period or a specific regularity. The optical position detecting means is a position detecting device for detecting the position of the light received in the blinking cycle or the blinking rule, and the light from the detected object and the light from other light emitting parts are included. It has an effect that it can be easily separated and the detection accuracy can be improved.

The invention according to claim 8 of the present invention is the invention according to any one of claims 2 to 7, wherein the optical position detecting means is provided on the back surface of the screen portion or from the back surface of the screen portion. A position detecting device arranged in the vicinity of a projection unit for projecting and displaying visual information, wherein an infrared ray emitted from an object to be detected moving on the screen unit is transmitted to the back side of the screen unit to detect an optical position. Since the position is detected by receiving the light, the position of the object to be detected can be accurately detected.

According to a ninth aspect of the present invention, in the eighth aspect of the invention, the projection image of the projection unit is transmitted and the detected object is present on the optical path from the object to be detected to the optical position detecting means. A position detecting device in which a reflector that reflects infrared rays emitted by the body, or a reflector that restrictively reflects light of a wavelength emitted from the object to be detected is arranged, and a projected image of visible light and a detection signal are displayed. It has the effect of ensuring reliable separation.

According to a tenth aspect of the present invention, in the invention according to the eighth or ninth aspect, at least a part of the projection unit is a position detecting device which is shared with the optical position detecting means, and the number of parts is increased. Is reduced and the structure is simplified.

The invention described in claim 11 of the present invention is, in the invention described in any one of claims 2 to 10, means for electrically correcting optical system distortion of position detection by the optical position detection means. The position detecting device is provided with an effect that the detection position accuracy can be improved even if the optical system of the optical position detecting means is distorted.

According to a twelfth aspect of the present invention, in the invention according to any one of the second to eleventh aspects, a light emitting portion is provided at two or more places around the screen portion, and the screen portion and the optical portion are provided. It is a position detection device that calibrates the position with the target position detection means, and has the effect of being able to detect the position of the object to be detected with high accuracy.

According to a thirteenth aspect of the present invention, an electronic blackboard using the position detecting device according to any one of the second to twelfth aspects for detecting the position of a detection object which is an electronic pen. This is a device, and has an effect that it is possible to obtain an electronic blackboard device that can accurately detect the position of the electronic pen with a simple configuration.

FIG. 1 shows an embodiment of the present invention.
From now on, description will be made with reference to FIG. In addition, in these drawings, the same members are denoted by the same reference numerals, and duplicate description is omitted.

(Embodiment 1) FIG. 1 is a schematic diagram showing an interactive electronic blackboard according to Embodiment 1 of the present invention.
2 is an explanatory diagram showing an example of an output waveform of horizontal position detection by the infrared camera installed on the interactive electronic blackboard of FIG. 1, and FIG. 3 is an output waveform of vertical position detection by the infrared camera installed on the interactive electronic blackboard of FIG. It is explanatory drawing which shows an example of a waveform.

An interactive electronic blackboard (electronic blackboard device) 101 shown in FIG. 1 has a screen (screen part) 105 having a light transmitting property such as translucent as a description part, and visual information such as an image from the back of the screen 105. It has a projection unit 102 for projection display. A first mirror 103 and a second mirror 104 that reflect the optical display data emitted from the projection unit 102 are arranged on the optical path from the projection unit 102 to the screen 105.

Also, this interactive electronic blackboard 10
1, when the tip is pressed against the screen 105,
Alternatively, an electronic pen (object to be detected) 107 that emits infrared light when a provided switch is pressed is prepared.
On the back side of the screen 105, a CCD which is an infrared area sensor is used, and an infrared camera (optical position detecting means) 106 for detecting the infrared rays emitted from the electronic pen 107 and transmitted to the back side of the screen 105.
Is installed. A personal computer (computer device) that takes in the trajectory data of the electronic pen 107 and outputs the display data of the screen 105 to the projection unit 102.
108 is provided.

Then, the position detecting device includes the screen 10
5, the electronic pen 107 and the infrared camera 106 are included.

Including the embodiments described below,
The light applied to the detection may be light having a wavelength other than infrared light.

In the electronic blackboard 101 having such a structure, when the electronic pen 107 is used to write on the screen 105, the electronic pen 107 emits infrared rays according to the locus. This infrared ray is captured by an infrared camera 106 which is an infrared area sensor installed on the back surface of the screen 105. The image pickup position of the infrared camera 106, which is an area sensor, and the light emission position on the screen 105 are correlated, and the screen 10 is corrected by correcting the display position and the position of the electronic pen 107 during use.
The position of the electronic pen 107 on 5 is detected.

If the electronic pen 107 emits infrared rays when its tip is pressed against the screen 105, the electronic pen 107 moves in contact with the screen 105.
If the electronic pen 107 emits infrared light when the switch is pressed, the electronic pen 107 will move to the screen 105.
It emits infrared light whether it is in contact with or not. Therefore, in the present specification, the movement of the electronic pen 107 on the screen 105 includes not only the movement of the electronic pen 107 in contact with the screen 105 but also the movement of the electronic pen 107 without contact.

FIG. 2 shows an example of the output waveform of horizontal position detection by the infrared camera 106.

In FIG. 2, reference numeral 109 is an output signal from the infrared camera 106, reference numeral 110 is a horizontal synchronizing signal, reference numeral 111 is a video signal, reference numeral 112 is a horizontal period, and reference numeral 11 is shown.
Reference numeral 3 is an infrared detection signal of a portion of the video signal 111 that receives infrared light, and reference numeral 114 is a calibration position of the video signal whose horizontal position is calibrated.

Electronic pen 1 incident on the infrared camera 106
The infrared ray of 07 is CC which is an area sensor through the lens.
Output signal 1 from the infrared camera 106 that is imaged on D
The video signal 111 of 09 is captured as an infrared detection signal 113.

Here, the CCD, which is the area sensor of the infrared camera 106, uses a crystal oscillator or the like as a reference signal and is controlled in a very accurate cycle. Therefore, the output signal is also repeatedly output at the constant horizontal period 112. At this time, the code 1 which is the known position
If the position and the video signal are calibrated at the calibration positions of 14, the horizontal time difference 115 between the calibration position 114 and the position of the infrared detection signal 113 of the detected CCD output signal is measured, and It is possible to detect the horizontal position of the electronic pen 107 that emits.

An example of the output waveform of the vertical position detection by the infrared camera 106 is shown in FIG.

In FIG. 3, reference numeral 116 is an output signal from the infrared camera 106, reference numeral 117 is a vertical synchronizing signal, reference numeral 118 is a video signal, reference numeral 119 is a vertical period, and reference numeral 12 is shown.
Reference numeral 0 is an infrared detection signal of a portion of the video signal 118 that receives infrared light, and reference numeral 121 is a calibration position of the video signal in which the vertical position is calibrated.

Electronic pen 1 incident on the infrared camera 106
The infrared ray of 07 is CC which is an area sensor through the lens.
Output signal 1 from the infrared camera 106 that is imaged on D
The 16 video signals 118 are captured as the infrared detection signal 20.

Here, the CCD, which is the area sensor of the infrared camera 106, uses a crystal oscillator or the like as a reference signal as well as a horizontal synchronizing signal, and is controlled in a very accurate cycle. Therefore, the output signal also has a constant vertical period 1
It is repeated in 19 and is output. At this time, if the position and the video signal are calibrated at the calibration position of reference numeral 121 which is a known position, the C detected as the calibration position 121 is detected.
By measuring the vertical time difference 122 between the output signal of the CD and the infrared detection signal 120, the vertical position of the electronic pen 107 that emits infrared light can be detected.

The horizontal position or the vertical position of the electronic pen 107 can be detected by counting the number of CCD pixels of the calibration position and the current infrared detection output instead of measuring the time as described above. .

The loci in the horizontal and vertical directions of the electronic pen 107 detected in this way are taken as locus data into the personal computer 108 to be described data. Then, the data taken in by the personal computer 108 is projected through the projection unit 102, and is projected and displayed as characters on the position described by the electronic pen 107 on the screen 105.

As described above, according to the present embodiment, the electronic pen 1 that moves on the screen 105 having a light transmitting property.
Since the infrared rays emitted from 07 are transmitted to the back side of the screen 105 and received by the infrared camera 106 which is an area sensor, the position of the electronic pen 107 can be accurately detected.

Further, since the infrared camera 106 uses a CCD as an area sensor, it can have a high sensitivity even in the infrared region and can be a high resolution area sensor, which has a high resolution and the arrangement of each pixel. Because of the high accuracy, position detection can be performed with high detection sensitivity and high accuracy.

Since the light emitted from the electronic pen 107 is infrared rays and the area sensor is the infrared camera 106 having sensitivity to infrared rays, it can be easily separated from the display data of the visible light projected by the projection unit 102, and it can be surely performed. Moreover, the position of the electronic pen 107 on the screen unit 105 can be specified.

Further, the electronic pen 107 has a tip which is pressed against the screen 105, or the electronic pen 10
Infrared light is emitted when the switch provided in 7 is pressed, so infrared light is emitted only in the handwriting portion to be displayed on the screen 105, and the handwriting portion and the simple electronic pen 107 are moved. The state can be separated, and the emission position of infrared rays as display information can be used as the trajectory data.

Here, by setting the light emission period of the infrared rays provided in the electronic pen 107 to a specific period, it is possible to discriminate the light reception signal from the infrared camera 106 at that period, so that the light emission signals from other light emitting units can be discriminated. It can be easily separated from light, and detection accuracy can be improved.

Further, by making the infrared light emission provided in the electronic pen 107 a blinking light emission having a specific regularity, it is possible to discriminate a light reception signal from the infrared camera 106 at a cycle having a specific regularity. Therefore, it is possible to easily separate the light from the other light emitting portions and increase the detection accuracy.

The discrimination of the received light signal having the periodicity or regularity can be performed not only by hardware but also by software processing.

Furthermore, the data of the infrared camera 106 is
A correction data table is created from data in which the distortion of the optical system is known or is calibrated at many points on the screen 105, and the infrared camera 106 receives light by numerically correcting the horizontal position and the vertical position using the correction table. In this case, for example, there is barrel distortion or reflection mirror distortion due to the lens system, the projection system and the infrared camera 1
Even if there is a difference in the angle of view of 06, the detection position can be accurately detected.

At least a part of the projection unit 102 can be shared with the infrared camera 106. In this way, the number of parts can be reduced and the structure of the device can be simplified.

(Embodiment 2) FIG. 4 is a schematic diagram showing an interactive electronic blackboard according to Embodiment 2 of the present invention.

The interactive electronic blackboard 101 of the present embodiment is provided with an infrared camera 106 arranged near the projection unit 102 instead of the infrared camera 106 on the back side of the screen 105 in the first embodiment. The infrared camera 106 is arranged at a position where infrared rays emitted from the electronic pen 107 are sequentially reflected by the second mirror 104 and the first mirror 103 and are incident thereon. Then, the infrared camera 10 according to the present embodiment
6 also uses a CCD which is an infrared area sensor, and detects infrared rays emitted from the electronic pen 107, as in the first embodiment.

By arranging the infrared camera 106 in the vicinity of the projection unit 102 in this manner, the angle of view of the projection unit 102 and the angle of view of the infrared camera 106 can be made substantially equal, and the optical system can be shared. Therefore, the configuration can be simplified.

On the front surface of the infrared camera 106, a filter 124 such as a bandpass filter or a low pass filter that attenuates visible light and transmits infrared light is installed.

In the interactive electronic whiteboard 101 having such a configuration, the screen 105 is displayed by the electronic pen 107.
With the above description, the electronic pen 107 emits infrared rays according to the locus. The infrared rays are sequentially reflected by the second mirror 104 and the first mirror 103, and the infrared camera 1 which is an infrared area sensor installed near the projection unit 102.
It is copied in 06. There is a correlation between the image pickup position of the infrared camera 106, which is an area sensor, and the light emission position on the screen 105, and the position of the electronic pen 107 on the screen 105 is corrected by correcting the display position and the position of the electronic pen 107 during use. Is detected.

The locus of the electronic pen 107 detected in this way is taken into the personal computer 108 as character data to be described data. Then, the data captured by the personal computer 108 is projected through the projection unit 102, and the electronic pen 10
The characters are projected and displayed on the screen 105 at the position indicated by 7.

As described above, since the filter 124 is installed on the front surface of the infrared camera 106, the projected image of visible light and the detection signal can be reliably separated.

It should be noted that instead of using the infrared camera 106, an area sensor having a sensitivity in the infrared region is used, and as shown in FIG. 4, a bandpass filter or a low-pass filter 124 for transmitting infrared rays is provided between the area sensor and the screen 105. Even if installed, the same effect can be obtained.

At this time, if the band filter or the low-pass filter 124 for transmitting infrared rays is located between the area sensor and the screen 105, the position shown in FIG.
The position is not limited to.

(Embodiment 3) FIG. 5 is a schematic diagram showing an interactive electronic blackboard according to Embodiment 3 of the present invention.

The interactive electronic blackboard 101 of the present embodiment is provided with an infrared camera 106 arranged near the projection unit 102 instead of the infrared camera 106 on the back side of the screen 105 in the first embodiment.

The infrared camera 106 is used for the electronic pen 10
The infrared rays emitted from the light source 7 are sequentially reflected by the second mirror 104 and the reflecting plate 125 and are arranged at a position where they are incident. Here, the reflection plate 125 is composed of a half mirror that transmits the projection image of the projection unit 102 and reflects the infrared rays emitted by the electronic pen 107, or a mirror that reflects the infrared rays of the wavelength emitted by the electronic pen 107 in a limited manner.

The infrared camera 106 of the present embodiment also uses a CCD which is an infrared area sensor, and detects infrared rays emitted from the electronic pen 107, as in the first embodiment.

In the interactive electronic blackboard 101 having such a configuration, the screen 105 is displayed by the electronic pen 107.
With the above description, the electronic pen 107 emits infrared rays according to the locus. The infrared rays are sequentially reflected by the second mirror 104 and the reflection plate 125, and are taken by the infrared camera 106 which is an infrared area sensor. There is a correlation between the image pickup position of the infrared camera 106, which is an area sensor, and the light emission position on the screen 105, and the position of the electronic pen 107 on the screen 105 is corrected by correcting the display position and the position of the electronic pen 107 during use. Is detected.

The locus of the electronic pen 107 detected in this way is taken into the personal computer 108 as character data to be described data. Then, the data captured by the personal computer 108 is projected through the projection unit 102, and the electronic pen 10
The characters are projected and displayed on the screen 105 at the position indicated by 7.

Here, since the reflecting plate 125 on the optical path is a half mirror or a mirror that reflects infrared rays having a specific wavelength, the image projected from the projection unit 102 is reflected by the reflecting plate 12.
After passing through 5, the light is reflected by the second mirror 104, and the projected image of visible light and the detection signal are reliably separated and displayed as characters on the screen 105 at the position described by the electronic pen 107.

The reflecting plate may be a semi-transparent mirror or a mirror that reflects infrared rays of a specific wavelength. In this case, the loss of the projection light of the projection unit 102 that transmits the light should be reduced. You can

(Embodiment 4) FIG. 6 is a schematic view showing an interactive electronic blackboard according to Embodiment 4 of the present invention from the back side.

The illustrated interactive electronic blackboard 101
Then, the first infrared light emitting element (light emitting portion) 127, the second infrared light emitting element (light emitting portion) 128, and the third infrared light emitting element (light emitting portion) 1 that correct the data of the electronic pen 107.
29 are arranged around the screen 105.

According to this, when the interactive electronic blackboard 101 is started up, the respective infrared light emitting devices 127, 1
28 and 129 are sequentially emitted, and their positions are detected by the infrared camera, whereby the image position on the infrared camera and the position on the screen 105 are corrected. In this way, by always calibrating the reference position with respect to the screen 105 at startup, the position of the electronic pen 107 can be accurately detected.

In addition, the first and second calibration
The third infrared light emitting elements 127, 128, 129 are described to emit light sequentially at startup, but the same effect can be obtained even if the third infrared light emitting elements 127, 128, 129 are made to emit light at all times for calibration.

In the present embodiment, the case where three infrared light emitting elements for calibration are provided has been described.
It is only necessary to correct two components, horizontal and vertical, and the same effect can be obtained by providing two or more infrared light emitting elements, for example, two diagonally provided components.

[0089]

As described above, according to the present invention, the infrared rays emitted from the object to be detected moving on the screen portion are transmitted to the back side of the screen portion and received to detect the position. As a result, it is possible to obtain an effective effect that the position of the object to be detected can be accurately detected.

If the optical position detecting means is provided with an area sensor composed of a CCD, the effective effect that the detection sensitivity is high and the position can be detected with high accuracy can be obtained.

If the light emitted from the object to be detected is infrared light, the effective effect that the projected image of visible light and the detection signal can be reliably separated is obtained.

If a filter that attenuates visible light and transmits infrared light is arranged on the optical path between the optical position detecting means and the screen portion, the projected image of visible light and the detection signal can be reliably separated. Effective effect is obtained.

If the object to be detected emits light when its tip is pressed against the screen part or when a switch provided on the object is pressed, only the part to be displayed on the screen part emits light. As a result, the detected object is separated from the mere moving state of the detected object, and the effective effect that the light emission position as the display information can be used as the trajectory data is obtained.

The light emitted from the object to be detected has a specific emission period or blinking emission having a specific regularity, and the optical position detecting means detects the position of the light received in the blinking period or the blinking rule. By doing so, it is possible to easily separate the light from the object to be detected and the light from other light emitting portions, and it is possible to obtain an effective effect that the detection accuracy can be improved.

If the optical position detecting means is arranged on the back surface of the screen portion or in the vicinity of the projection portion for projecting and displaying visual information on the screen portion from the back surface, light is emitted from the detected object moving on the screen portion. Since infrared rays are transmitted to the back side of the screen section and received by the optical position detecting means for position detection, the angle of view of the projection section and the angle of view of the infrared camera can be made substantially equal, and the optical system is shared. This makes it possible to simplify the configuration and to effectively detect the position of the object to be detected.

On the optical path from the object to be detected to the optical position detecting means, a reflection plate that transmits the projection image of the projection unit and reflects infrared rays emitted by the object to be detected, or light of a wavelength emitted from the object to be detected. By arranging a reflection plate that reflects light in a limited manner, the effective effect that the projected image of visible light and the detection signal can be reliably separated can be obtained.

If at least a part of the projection unit is also used as the optical position detecting means, an effective effect that the number of parts is reduced and the structure is simplified can be obtained.

If the means for electrically correcting the optical system distortion of the position detection by the optical position detecting means is provided, the detection position accuracy can be improved even if the optical system of the optical position detecting means is distorted. Effective effect is obtained.

If the light emitting parts are provided at two or more places around the screen part and the positions of the screen part and the optical position detecting means are calibrated, the position of the object to be detected can be detected with high accuracy. The effective effect of being able to do is obtained.

According to the electronic blackboard device using such a position detecting device, an effective effect that an electronic blackboard device capable of accurately detecting the position of the electronic pen with a simple structure can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an interactive electronic blackboard according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an example of an output waveform of horizontal position detection by an infrared camera installed on the interactive electronic blackboard of FIG.

FIG. 3 is an explanatory diagram showing an example of an output waveform of vertical position detection by the infrared camera installed on the interactive electronic blackboard of FIG.

FIG. 4 is a schematic diagram showing an interactive electronic blackboard according to the second embodiment of the present invention.

FIG. 5 is a schematic diagram showing an interactive electronic blackboard according to a third embodiment of the present invention.

FIG. 6 is a schematic view showing an interactive electronic blackboard according to a fourth embodiment of the present invention from the back side.

FIG. 7 is a schematic view showing a state of using a conventional interactive electronic blackboard device.

[Explanation of symbols]

101 Interactive electronic blackboard (electronic blackboard device) 102 Projector 103 First mirror 104 Second mirror 105 screen (screen part) 106 infrared camera (optical position detection means) 107 Electronic pen (object to be detected) 108 Personal computer (computer device) 109 output signal 110 Horizontal sync signal 111 video signal 112 horizontal cycles 113 infrared detection signal 114 calibration position 115 Horizontal time difference 116 output signal 117 Vertical sync signal 118 video signal 119 Vertical cycle 120 infrared detection signal 121 Calibration position 122 Vertical time difference 124 Low-pass filter 125 reflector 127 First infrared light emitting element (light emitting section) 128 Second infrared light emitting element (light emitting section) 129 Third infrared light emitting element (light emitting section) 201 frame 202 control unit 203 written surface 204 caster mechanism 205 Receiver 206 Receiver 207 Electronic pen (object to be detected) 208 Projector 209 PC

Claims (13)

[Claims] 1. A light-transmissive object which moves on a screen portion displaying a projected image is emitted from the object and transmitted to the back side of the screen portion. A position detecting method characterized by receiving and detecting light of a predetermined wavelength. 2. A screen portion which is light-transmissive and displays a projected image, a detected body which emits light of a predetermined wavelength while moving on the screen portion, and a light emitted from the detected body. And a position detecting device for detecting the position of the object to be detected by receiving light transmitted to the back side of the screen portion. 3. The position detecting device according to claim 2, wherein the optical position detecting means includes an area sensor including a CCD. 4. The position detecting device according to claim 2, wherein the light emitted from the object to be detected is infrared light. 5. A filter for attenuating visible light and transmitting infrared rays is arranged on an optical path between the optical position detecting means and the screen portion. Position detection device. 6. The object to be detected emits light when its tip is pressed against the screen portion or when a switch provided on the object is pressed. The position detecting device as described in 1 above. 7. The light emitted from the object to be detected is a flashing light emission having a specific light emission cycle or a specific regularity, and the optical position detecting means detects the light received at the flashing cycle or the blinking rule. The position detecting device according to claim 2, wherein a position is detected. 8. The optical position detecting means is arranged on the back surface of the screen portion or in the vicinity of a projection portion for projecting and displaying visual information from the back surface on the screen portion. 7. The position detection device according to claim 7. 9. A reflecting plate, which transmits an image projected by the projection unit and reflects infrared rays emitted from the detected object, on an optical path from the detected object to the optical position detecting means.
9. The position detecting device according to claim 8, further comprising a reflector plate that reflects light of a wavelength emitted from the object to be detected in a limited manner. 10. The position detecting device according to claim 8, wherein at least a part of the projection unit is shared with the optical position detecting means. 11. The position detecting device according to claim 2, further comprising means for electrically correcting optical system distortion of position detection by the optical position detecting means. 12. A light emitting portion is provided at two or more places around the screen portion to calibrate the positions of the screen portion and the optical position detecting means. The position detection device according to any one of claims. 13. An electronic blackboard device using the position detecting device according to claim 2, which detects a position of the object to be detected, which is an electronic pen.