JP3134814U - Coordinate detection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent foreign matter from being mixed in a coordinate detection apparatus using an image sensor.
An image sensor that captures a coordinate indicator approaching or touching a coordinate input surface, and calculating and outputting a coordinate position of the coordinate indicator on the coordinate input surface based on the image of the captured coordinate indicator. In the coordinate detection apparatus, the image sensor is installed above the coordinate input surface, the photographing direction is installed downward, and a cover for concealing the outer surface of the image sensor is attached. It is characterized by being. In addition, a light-transmitting dustproof filter is attached in front of the field of view of the image sensor. In addition, a fan for removing dust from the light-transmitting dustproof filter is attached.
[Selection] Figure 5

Description

  The present invention relates to a coordinate detection apparatus using an image sensor, and in particular, to prevent foreign matter from entering the field of view of the image sensor and from contacting the image sensor, a substrate, a cable, etc. from the outside. It is related to the means.

In recent years, an electronic whiteboard (Interactive White Board, hereinafter abbreviated as IWB) has been spreading.
IWB uses PDPs, LCDs, projectors, etc., which are used as general display devices, and uses input means such as fingers and electronic pens and a coordinate detection device on the display screen as if they were input with chalk on the blackboard. This is realized by processing the input information by an arithmetic device such as a personal computer (PC) and projecting the processing result on a display device.

As coordinate detection devices, tablets, touch panels, and the like are prevalent. There are various techniques for realizing this, such as an electromagnetic induction system and an ultrasonic system.
In recent years, coordinate detection devices that use image processing by the image sensor that is the subject of the present invention have become widespread, and are used because of their good drawing responsiveness and strong resistance to external noise such as infrared rays, sunlight, and radio waves. The number of patent documents that use image sensors is increasing year after year.

JP-A-2005-4729 (position detecting device using area image sensor) JP 3817069 (coordinate input device)

In order to detect an input position on a coordinate input surface, a coordinate detection device using an image sensor needs to have an image sensor attached around the input surface.
As a main configuration, an image sensor and a control board for processing an image acquired by the sensor are necessary. By installing two or more image sensors, the position on the input surface is detected from a plurality of visual field positions, and calculation is performed by trigonometry.
These sensors and boards are not exposed to the outside for safety and quality assurance. This is necessary in order to avoid an electric shock accident caused by a user touching a board circuit or a mounting cable, and physical damage thereof.
In addition, by being exposed, it is likely to be affected by the surrounding environment, and for example, there is a high possibility that operational problems will be caused by receiving dust from the outside.
For this reason, these image sensors, substrates, cables, and the like are dealt with so as not to be easily touched by the user by installing a cover in order to isolate them from the outside.

However, since the image sensor needs to capture the input position on the input surface by the light receiving element of the sensor, an operation problem occurs if there is an obstacle having no light transmission on the detection surface. For this reason, a light-impermeable object cannot be installed in the imaging range of the image sensor.
For this reason, the detection surface of the image sensor cannot be shielded from the outside at all times. Therefore, it is a factor that increases malfunctions and malfunctions due to foreign foreign matter entering and adhering to the detection surface. It has been said.

  The purpose of the present invention is to solve these problems.

In order to achieve the above object, a coordinate detection apparatus according to the present invention includes an image sensor that captures a coordinate indicator approaching or touching a coordinate input surface, and the coordinate indicator based on the image of the captured coordinate indicator. In a coordinate detection apparatus comprising a calculation means for calculating and outputting a coordinate position on the coordinate input surface of
The image sensor is installed above the coordinate input surface, the photographing direction is installed downward, and a cover for concealing the outer surface of the image sensor is attached.
In addition, a light-transmitting dustproof filter is attached in front of the field of view of the image sensor.
In addition, a fan for removing dust from the light-transmitting dustproof filter is attached.

According to the present invention, since the visual field direction of the image sensor and the direction of gravity coincide with each other, it is possible to reduce the intrusion of dust or dust floating in the air into the image sensor.
In addition, the installation of the image sensor above makes it difficult to reach the hands of lower grades in elementary schools where IWB is mainly used, so that trouble can be reduced.
In addition, the dustproof filter allows the image sensor to take an image of the coordinate pointing object on the input surface through the dustproof filter.
Further, since the image sensor is physically separated from the outside by the dustproof filter, it cannot be accessed from the outside. For this reason, even if it installs not only in the upper part of IWB but in the lower part and the left and right parts, it can cope with dust and mischief from the outside.
Furthermore, by providing a fan for removing dust on the dust filter, even if dust or dirt temporarily adheres to the dust filter, it is always removed by the wind of the fan, and the image sensor Malfunction can be prevented.

Hereinafter, an embodiment for carrying out the present invention will be specifically described with reference to the drawings.
FIG. 1 shows an outline of an image processing system using a coordinate detection apparatus using an image sensor targeted by the present invention.
In this system, the position of the pointing object 2 that has touched or approached the coordinate input surface 1 is captured by a plurality of image sensors 3 a and 3 b, and the coordinates of the pointing object 2 are obtained from images taken by the image sensors 3 a and 3 b on the control board 4. The position (X, Y) is calculated and output.
The upper part of the coordinates is sent to the arithmetic device 5 such as a personal computer, and the result is displayed on the coordinate input image 1 through the display device 6.
Here, the pointing object 2 may be a finger, a stick, an electronic pen having a communication function such as infrared rays, an electronic pen having an additional function linked with the control board 4, or the like.
As the display device 6, a method using a projector as shown in FIG. 1 or a display screen such as a PDP or an LCD can be used.

FIG. 2 is a diagram illustrating details of the image sensors 3a and 3b, and FIG. 3 is an explanatory diagram of functions of the image sensors 3a and 3b.
The image sensor uses a light receiving element such as a CCD or CMOS, and acquires an image through an imaging lens.
The image sensors 3a and 3b are provided with a plurality of light sources that emit light such as LEDs 7. The LED 7 irradiates light to the reflective tape installed in the reflective frames 8a, 8b, and 8c installed so as to surround the coordinate input surface 1.
The reflective tape uses a retroreflective material such as a corner cube reflector. The image sensors 3a and 3b receive the light retroreflected by the reflecting tape.

When the pointing object 2 is in contact with the coordinate input surface 1, the light from the LED 7 is blocked. At this time, the shadow image of the pointing object 2 is photographed by the plurality of image sensors 3 a and 3 b, and the coordinates are calculated by the control board 4.
When the image sensor 3b is photographed, the image at this time is photographed as a shadow image at the designated object position 31 in the reflection frame (lower) in FIG.
Similarly, when the image sensor 3a captures an image, the image at this time is captured as a shadow image at the position of the pointing object position 32 on the reflection frame (lower) in FIG.
The light source may be a method of irradiating the entire input surface by rotating LED light as described in Patent Document 2 with a polygon mirror.

FIG. 4 is a view showing a cover installed on the upper part of the coordinate input surface 1.
Since an object that does not transmit light cannot be placed within the range of the field of view of the image sensors 3a and 3b, the other range is covered with a cover 9 and concealed.
Thereby, since the direction of the opening part of the cover 9 and the direction of gravity can be made to correspond, it can reduce that the dust etc. which float in the air approach from an opening part.

FIG. 5 is a diagram showing the overall configuration of the dust-proof structure of the image sensor according to the present invention.
First, as shown in FIG. 5A, a cover 9 that covers the image sensors 3a and 3b is provided, and the image sensors 3a and 3b are attached to the upper part of the coordinate input surface so that the field of view of the image sensors 3a and 3b faces downward. This is because the openings of the sensors 3a and 3b are directed downward to prevent foreign matter from entering from the outside and to prevent malfunction of the image sensors 3a and 3b.
In addition, as shown in FIG. 5 (b), by providing a light-transmitting dust-proof filter 10 at the openings of the image sensors 3a and 3b, a structure that prevents entry of foreign matter and access from the outside is provided. It is.
Further, as shown in FIG. 5C, a fan 11 is provided at a position close to the dust-proof filter 10 to prevent foreign matter from entering and accessing from outside, and dust on the filter 10 is caused by the wind of the fan 11. This means that the field of view of the image sensors 3a and 3b is always clearer.

1 is a system configuration diagram showing an embodiment of an image processing system using a coordinate detection device of the present invention. It is a figure which shows the structure of the image sensor, the reflective frame, the control part, etc. which comprise the coordinate detection apparatus of this invention. It is a schematic block diagram of the coordinate detection method of the coordinate detection apparatus which concerns on this invention. It is a schematic block diagram of the cover of the coordinate detection apparatus which concerns on this invention. It is a figure which shows the whole structure of the dust-proof structure of the image sensor which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coordinate input surface 2 Pointing object 3a, 3b Image sensor 4 Control board 7 LED
8a to 8c Reflective frame 9 Cover 10 Dust-proof filter 11 Fan

Claims (3)

An image sensor that captures a coordinate indicator that is approaching or touching the coordinate input surface; and an arithmetic unit that calculates and outputs a coordinate position of the coordinate indicator on the coordinate input surface based on the image of the captured coordinate indicator. In a coordinate detection apparatus comprising:
A coordinate detection apparatus, wherein the image sensor is installed above the coordinate input surface, the photographing direction is installed downward, and a cover for concealing the outer surface of the image sensor is attached.   The coordinate detection apparatus according to claim 1, wherein a light-transmitting dustproof filter is attached in front of the visual field of the image sensor.   The coordinate detection apparatus according to claim 2, further comprising a fan for removing dust from the light-transmitting dustproof filter.

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