JP2001277785A - Electronic blackboard - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic blackboard which is equipped with a two-dimensional image sensor and is capable of certainly reading the color of a described image. SOLUTION: A two-dimensional image sensor with partially transparent pixels is formed on the surface of a glass substrate and a light source is arranged opposite to the image sensor and thus the electronic blackboard which reads an image described on the back of the substrate is constituted. When the shape of the image is read, an environmental light from the back of the substrate is detected using the image sensor. When the color of the image is read, the light, from the light source, which is reflected by the image is detected with the help of the image sensor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic blackboard on which an image is recorded and which reads the image, and more particularly to an electronic blackboard which reads an image with a two-dimensional image sensor.

[0002]

2. Description of the Related Art Electronic blackboards that read images such as written characters and pictures and perform processes such as storage, copying, and transfer have become widespread. In a conventional electronic blackboard, an image is read by using a one-dimensional image sensor called a scanner and changing the relative position between the sensor and the image.
However, in this configuration, a driving mechanism for changing the relative position between the sensor and the image is required, and the apparatus is inevitably complicated and large. Further, it takes time to read, and there is a limit in improving the processing efficiency.

In recent years, there has been proposed an electronic blackboard provided with a two-dimensional image sensor and reading a written image at a time. For example, Japanese Patent Application Laid-Open No. 6-326805 discloses an electronic blackboard having a structure in which a two-dimensional image sensor is formed on the surface of a substrate, and the sensor is covered with a transparent sheet to read an image written on the sheet. Is disclosed.

[0004]

However, a conventional electronic blackboard having a two-dimensional image sensor detects an image that blocks light passing through a transparent sheet as a shadow, so that it is difficult to read the color of the image well. . Further, the two-dimensional image sensor provided on the electronic blackboard described in the above publication is
Because it is made of an organic material because it can be made in a large area, it gradually deteriorates, and if used for a long period of time, the read image tends to generate noise or the image cannot be read.

[0005] The present invention has been made in view of such a problem, and is an electronic blackboard for reading an image with a two-dimensional image sensor, which can reliably read a color and further has durability. The purpose is to provide something excellent.

[0006]

In order to achieve the above object, the present invention provides a transparent substrate and a two-dimensional image sensor provided on the surface of the transparent substrate. An electronic blackboard for reading an image includes a light source that makes at least a part of the image sensor light-transmissive and illuminates the transparent substrate from the front side of the transparent substrate.

This electronic blackboard reads an image written on the back surface of a transparent substrate with a two-dimensional image sensor. At least a part of the image sensor transmits light so that it is written on the back surface of the transparent substrate. Image can be illuminated with light from a light source. Therefore, the image sensor can receive not only environmental light from the back surface transmitting through the transparent substrate but also light from the light source reflected by the image, and can use different light for reading the image. .

Here, the shape of the written image can be read by detecting environmental light from the back side of the transparent substrate with an image sensor. That is, the shape of the image is read as a shadow using ambient light. This way, if the user does not need the color of the image,
It is possible to avoid turning on the light source unnecessarily.

The color of the written image can also be read by detecting the light from the light source reflected by the written image with an image sensor. It is difficult to correctly read the color by detecting the image as a shadow using the ambient light, but if the reflected light is detected using the light from the light source in this way, the color of the image can be reliably read. Becomes possible. If you read in advance the shape of the image using the ambient light from the back side of the transparent substrate,
It is only necessary to process signals of pixels of a portion corresponding to an image among all pixels of the image sensor, and signal processing for reading a color can be efficiently performed.

It is preferable to provide an optical member between the light source and the image sensor for switching between transmitting and blocking light. When the light from the light source is not used, the light is blocked by the optical member, so that the light source can be prevented from being seen by a user located on the back surface side of the transparent substrate.

[0011] A diffusion plate for diffusing light may be provided between the light source and the image sensor. This way,
An image can be illuminated with uniform brightness.

[0012] The light source may emit white light. In this configuration, a special light source is not required, and a general light source such as a fluorescent tube can be used. Further, by providing a color filter on an optical path of light from a light source or a light receiving portion of each pixel of the image sensor, it is possible to read the color of an image.

[0013] The light source may emit light of a plurality of colors. In this case, the color of the image can be read without providing a color filter on the optical path of the light from the light source or the light receiving section of each pixel of the image sensor.

The image sensor is preferably made of an inorganic material. An inorganic material degrades more slowly than an organic material, so that an image can be read stably over a long period of time.

[0015] A light-transmitting protective film may be provided on the back surface of the transparent substrate. The surface on which the image is recorded can be prevented from being stained.

[0016] A memory for storing the read image may be provided. After reading the image, the user can use the image at any time.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the electronic blackboard of the present invention will be described with reference to the drawings. FIG. 1 shows the appearance of the electronic whiteboard 1 according to the first embodiment. In FIG.
(A) is a front view, (b) is a rear view. Electronic blackboard 1
Is a panel 10 on which an image such as a character or a picture is written by a user and which reads the image, an output unit 20 for outputting the read image, an operation unit 30 operated by the user, and a support frame 40 for supporting the whole. It has. Panel 10
An image is written using a color ink that is quick drying and easy to peel. The configuration of the panel 10 will be described later in detail.

The output unit 20 has a built-in printing device, and can copy a read image on paper and output it as a hard copy. Further, a memory card can be attached to the output unit 20, and the read image can be stored in the memory card. The output unit 20 further includes
It can be connected to an external device such as a personal computer via a cable (not shown), and the read image can be transmitted to the external device. At the front of the output unit 20, there are provided a paper discharge port 21 for discharging paper on which an image has been copied, and an insertion port 22 for mounting a memory card, and at the back, a connector 23 for attaching a cable is provided. Have been.

FIG. 2 shows the upper surface of the operation unit 30. Operation unit 3
0 is a power button 31, a storage button 32, a copy button 3
3, transmission button 34, multiple function buttons 3
5, a plurality of input buttons 36, and a liquid crystal display 37. The electronic blackboard 1 operates with the power of a commercial power supply, and the power button 31 is used to instruct switching of supply and stop of power supply to the panel 10, the output unit 20, and the operation unit 30 that require power. The storage button 32 is used to instruct storage of the read image on the memory card, and the copy button 33 is used to instruct output of the read image to paper. Also,
The transmission button 34 is used to instruct transmission of the read image to an external device.

The function button 35 is used to instruct the operation of the electronic blackboard 1 to be changed, and the input button 36 is used by the user to arbitrarily add information such as the user's name, image name, date and time to the read image. Used to enter.
The liquid crystal display 37 is used for providing guidance on operation and input buttons 36.
To display the input information.

FIG. 3 is an enlarged perspective view of a part of the panel 10. The panel 10 includes a transparent glass substrate 11 and an image sensor 1 provided on the surface of the substrate 11.
2, a light source 16, a liquid crystal shutter 17, and a protective film 18 provided on the back surface of the substrate 11. The panel 10 is fixed to the support frame 40 so that the back surface of the substrate 11, that is, the surface on the opposite side of the image sensor 12 faces outward, and the user writes an image on the protective film 18.

The image sensor 12 has a large number of pixels 13 of two.
They are arranged in dimensions. Each pixel 13 includes a photodiode 14 as a light receiving unit, and a thin film transistor (TFT) 15 that outputs a charge generated by the photodiode by photoelectric conversion.

The photodiode 14 is formed so as to receive light from the substrate 11 side, and the side opposite to the substrate 11 is shielded from light. The TFT 15 is shielded from light on the substrate side and on the opposite side. The portion of each pixel 13 except for the photodiode 14 and the TFT 15 is light-transmissive. This light transmitting portion occupies more than half of the area of each pixel. Therefore, the image sensor 12 covers the entire surface thereof.
50% or more is light transmissive.

The photodiode 14 of each pixel 13 has
A filter 14R for selectively transmitting red (R) light,
A filter 14G for selectively transmitting green (G) light,
One of the filters 14B that selectively transmits blue (B) light is provided, and all the photodiodes 1 are provided.
No. 4 is classified into three types for R light, G light and B light. These three types of photodiodes are arranged in a Bayer type.

The light source 16 illuminates the substrate 11 with the emitted light from the front side. As described above, the image sensor 12 has light transmittance, and light from the light source 16 reaches the substrate 11. In the electronic whiteboard 1 of the present embodiment, a fluorescent tube 16a is used as the light source 16, and the light source 16 emits white light including R light to B light.

The liquid crystal shutter 17 is an image sensor 12
And the light source 16. LCD shutter 17
Takes a transparent state and a cloudy state depending on whether or not a voltage is applied, and blocks light in the cloudy state. When the liquid crystal shutter 17 is cloudy, the light from the light source 16 cannot be used, and the light source 16 cannot be seen by a user located on the back side of the substrate 11. The liquid crystal shutter 17 is set to be in a transparent state when a voltage is applied, and to be in a cloudy state when no voltage is applied. Therefore, when the light from the light source 16 is not used, no power is consumed by the liquid crystal shutter 17.

The protective film 18 is transparent and has a function of protecting the back surface of the substrate 11, easily adhering ink before drying, and easily peeling ink after drying. Any material may be used as long as it has such characteristics. Here, a polyethylene terephthalate film is used as the protective film 18 and the substrate 1 is made of a transparent adhesive.
1 on the back. In addition, the protective film 18 is omitted,
It is possible to write the image directly on the back surface of the substrate 11. However, in order to prevent the substrate 11 from being stained and to be able to read a high-quality image for a long time, the protective film 1 is used.
8 is preferred.

The image sensor 12 can always receive ambient light from the back side of the substrate 11. If an image is written on the protective film 18, the image becomes a dark shadow on the image sensor 12, and is clearly distinguished from a bright portion where no image is written. Thereby, the shape of the image can be read. However, the amount of light received by the image sensor 12 in a shadow portion is small, and it is difficult to read a color.

When the light source 16 is turned on and the liquid crystal shutter 17 is made transparent, the image sensor 12 can also receive the light from the light source 16 reflected by the image. At this time, the image becomes a bright image on the image sensor 12, and therefore, a sufficient amount of received light enough to read the color of the image is obtained. However, when the environment is too bright, the amount of light received in the area where no image is written increases,
Reading the shape of the image becomes difficult.

Therefore, in the electronic blackboard 1, the shape of the image is read using the ambient light, and the color of the image is read using the light from the light source 16. This makes it possible to reliably read both the shape and the color of the image.
In addition, by reading the shape in advance, it is clear which of the signals output by all the pixels 13 of the image sensor 12 should be processed when reading the color. improves.

FIG. 4 shows a schematic circuit configuration of the electronic whiteboard 1. The electronic blackboard 1 includes an image sensor 12, a light source 16, a liquid crystal shutter 17, an operation unit 30, a printing device 24 of an output unit 20, two interfaces 25, 26, and a CP.
U51, ROM52 and RAM53 are provided. The interface 25 is for storing an image on a memory card, and the interface 26 is for outputting an image to an external device. These are provided in the output unit 30.

The CPU 51 processes signals output from the image sensor 12 to generate image data representing an image and controls the operation of each unit. ROM 52 is CP
A program describing the processing performed by U51 is stored.
The RAM 53 is used by the CPU 51 for generating image data and holding input from the operation unit 30. CPU5
1, the ROM 52 and the RAM 53 are provided in the housing of the operation unit 30.

The processing of an image on the electronic whiteboard 1 will be described. FIG. 5 shows the flow of the entire image processing. First, the operation of the operation unit 30 is detected (step # 5). The operated button is the copy button 33 or the transmission button 3
4 or the storage button 32 (# 10, # 15, # 20). When the copy button 33 is operated, a process of reading an image and generating image data is performed (# 25), and the image represented by the image data is printed by the printing device 24 (# 30). When the transmission button 34 is operated, a process of reading an image and generating image data is performed (# 35), and the image data is transmitted to an external device via the connector 23 (# 40). When the storage button 32 is operated, a process of reading an image and generating image data is performed (# 45), and the image data is stored in a memory card (# 50).

When the function button 35 or the input button 36 is operated instead of any of these buttons, processing corresponding to the function is performed (# 55). For example, information to be added to image data is generated from characters and numbers input by operating the input button 36 and stored in the RAM 53. This information is printed together with the image as a character in the processing of step # 30, and is also performed in steps # 40 and # 50.
Is transmitted or stored together with the image data in the process of

FIG. 6 shows the flow of the processing for reading an image and generating image data in steps # 25, # 35 and # 45.
Shown in First, in order to read the shape of an image written on the protective film 18, ambient light from the back side of the substrate 11 is detected by the image sensor 12 (step # 105). The output signal of the image sensor 12 at this time is stored in the RAM 53. Next, a voltage is applied to the liquid crystal shutter 17 to make it transparent (# 110), and the light source 16 is turned on (# 115). Then, in order to read the color of the image written on the protective film 18, the light from the light source reflected by the image is detected by the image sensor (# 120). The output signal of the image sensor 12 at this time is also stored in the RAM 53.

Thereafter, the light source 16 is turned off (# 125).
The application of the voltage to the liquid crystal shutter 17 is stopped to return to a cloudy state (# 130). Then, image data representing an image is generated from the signal stored in the RAM 53 (# 135).
At this time, the shape of the image is determined from the signal stored in step # 105, and image data is generated using only the signal corresponding to the shape of the image among the signals stored in step # 120. Therefore, the time required for processing the detection result in step # 120 is short, and image data representing only an image can be reliably obtained.

When the user does not need the color of the image, steps # 110 to # 130 can be omitted, and image data representing a monochrome image can be generated in step # 135. In this way, power consumption can be reduced. Whether or not steps # 110 to # 130 are to be omitted can be arbitrarily set by the user by operating one of the function buttons 35.
This operation is performed prior to the operation of the storage button 32, the copy button 33, and the transmission button.

In the electronic blackboard 1 for reading the color of an image using the light from the light source 16 as described above, the protective film 18
Need not be colorless. That is, even if the protective film 18 is slightly colored, any material may be used as long as it can transmit light to such an extent that the shape of an image can be read.

A method for manufacturing the image sensor 12 will be described. The image sensor 12 is manufactured by using a method known in semiconductor technology such as sputtering, chemical vapor deposition (CVD), and patterning by photolithography. FIG. 7 shows a process of manufacturing the image sensor. FIG. 7 schematically shows a cross section corresponding to one pixel 13.

First, a TFT 15 is placed on a glass substrate 11.
Light-shielding layer 61 and the color filter of the photodiode 14
The transparent dielectric layer 62 that becomes the
(A). Cr is used for the light shielding layer 61 and is transparent.
As the dielectric layer 62, MgF _Two, Si_ThreeN_FourDielectric material such as
Use fee. The thickness of the transparent dielectric layer 62 is R, G, B
Adjust each pixel so that each light can be transmitted selectively.
You.

Next, a gate electrode layer 63 and an insulating layer 64 of the TFT are formed (b). A for the gate electrode layer 63
1, SiO ₂ or SiN is used as the insulating layer 64.

Then, the gate layer 65, the source layer 66 and the drain layer 67 of the TFT are formed, and the insulating layer 64 is formed again (c). Amorphous Si is used for the gate layer 65, the source layer 66, and the drain layer 67, and when the source layer 66 and the drain layer 67 are formed, N 3 -type impurities are doped using PH ₃ gas.

After the TFT is formed, the transparent electrode layer 68 for the photodiode 14 and the electrode connection layer 6 for the photodiode 14
9, a photoelectric conversion layer 70 and an electrode connection layer 71 are formed (d). ITO is used for the transparent electrode layer 68. As the electrode connection layers 69 and 71 and the photoelectric conversion layer 70, amorphous Si, SiGe, SiC or SiN is used. In forming the electrode connection layers 69 and 71, P-type impurities and N-type impurities are doped using B ₂ H ₆ gas and PH ₃ gas, respectively.

After the formation of the photodiode, an insulating layer 64 is formed, and the source electrode layer 72 and the drain electrode layer 7 of the TFT are formed.
3. A wiring layer 74 for connecting a transparent electrode and an electrode layer 75 for a photodiode are formed (e). Electrode layers 72, 7
3 and the wiring layer 74 are formed with a contact hole in advance. For the electrode layers 72, 73, 75 and the wiring layer 74, Al is used.

Finally, an insulating layer 64 is formed, and light-shielding layers 76 and 77 for a TFT and a photodiode are formed to complete an image sensor. Al is used as the light shielding layers 76 and 77.
Is used. After the completion of the image sensor, a protective film 18 is attached to the back surface of the substrate 11.

Note that the materials shown here are merely examples of usable materials, and the image sensor 12 may be manufactured using other materials. However, in order to have sufficient durability, it is preferable to use an inorganic material as described above.
In general, photodiodes are classified into a photoconductive type, a charge injection blocking type, a multiplication type, and the like according to a driving method. The photodiode 14 may be of any type.

Hereinafter, the electronic blackboard of the other embodiments will be described. However, the appearance and circuit configuration of the electronic blackboard of each embodiment are the same as those of the above-described electronic blackboard 1, and the overlapping description will be omitted, and the differences will be omitted. Only points will be described. The same or similar components as those already described are denoted by the same reference numerals.

The panel 10 of the electronic blackboard 2 of the second embodiment
FIG. 8 is an enlarged perspective view of a part of FIG. In the electronic whiteboard 1, the photodiode 14 of each pixel 13 of the image sensor 12 has a color filter and a fluorescent tube is used as the light source 16. However, in the electronic whiteboard 2 of the present embodiment, the photodiode 14 has a color filter. It is not provided, and instead, as the light source 16, R
Three types of light emitting diodes 16 for emitting light, G light or B light
R, 16G, and 16B are two-dimensionally arranged. The light emitting diodes 16R, 16G, and 16B each have a size corresponding to several pixels 13, and are arranged in a Bayer pattern.

FIG. 9 shows the flow of processing for reading an image and generating image data. First, in order to read the shape of an image written on the protective film 18, environmental light from the back side of the substrate 11 is detected by the image sensor 12 (step # 2).
05). The output signal of the image sensor 12 is stored in the RAM 53. Next, a voltage is applied to the liquid crystal shutter 17 to make it transparent (# 210).

Then, in order to read the color of the image written on the protective film 18, the light source 16 is turned on and the light from the light source reflected by the image is detected by the image sensor 12 (# 215 to # 240). . At this time, R
Light-emitting diodes 16R, 16G, 16 for light, G light, and B light
B individually (# 215, # 225, # 23
5) Each time the light detection and output signal RAM 53
(# 220, # 230, # 240). As a result, the photodiode 14 having no filter can be used.
It becomes clear which color light is received. The lighting order of the light emitting diodes 16R, 16G, 16B may be freely determined.

After the detection of the light of three colors, the light emitting diode which was turned on last is turned off (# 245), and the application of the voltage to the liquid crystal shutter 17 is stopped to return to the cloudy state (# 250).
Then, image data representing an image is generated from the signal stored in the RAM 53 (# 255). Also at this time, the shape of the image is determined from the signal stored in step # 205, and image data is generated using only the signal corresponding to the shape of the image among the signals stored in steps # 220, # 230, and # 240. I do.

As described above, it is possible to omit steps # 210 to # 250 and generate image data representing a monochrome image in step # 255, and it is not necessary to make the protective film 18 colorless. .

FIG. 10 schematically shows a cross section corresponding to one pixel 13 of the image sensor 12. In the first embodiment, the transparent dielectric layer 62 is formed to be used as a filter of the photodiode 14, but in the present embodiment, a transparent insulating layer 78 is formed by using SiO ₂ instead of the transparent dielectric layer. I do. Other layers are formed by the method described with reference to FIG.

The panel 10 of the electronic blackboard 3 of the third embodiment
FIG. 11 is an enlarged perspective view of a part of FIG. The electronic blackboard 3 is a light source 16 of the electronic blackboard 1 of the first embodiment.
Diffuser 19 for diffusing light between
Is arranged.

The panel 10 of the electronic blackboard 4 of the fourth embodiment
FIG. 12 shows a perspective view in which a part of is enlarged and seen through. This electronic blackboard 4 is a light source 16 of the electronic blackboard 2 of the second embodiment.
A diffusion plate 19 is arranged between the liquid crystal shutter 17 and the liquid crystal shutter 17.

In these electronic blackboards 3 and 4, the diffusion plate 19
Is provided, the image written on the protective film 18 can be illuminated with more uniform brightness, and the density and color of the read image do not become uneven. Note that the diffusion plate 19 may be arranged between the image sensor 12 and the liquid crystal shutter 17.

The panel 10 of the electronic blackboard 5 of the fifth embodiment
FIG. 13 is a perspective view in which a part of is enlarged and seen through. First
In the electronic blackboard 1 of the embodiment, the color filter is provided on the light receiving surface side of the photodiode 14 of each pixel 13 of the image sensor 12, but in the electronic blackboard 5, the color filter is provided on the light receiving surface side of the photodiode 14. Is not provided, and a color filter is provided on the surface of each pixel 13 on the light source 16 side. R for color filter
Light, G light and B light are selectively transmitted.
A color filter 13R that transmits light, G light, and B light;
13G and 13B are arranged in a Bayer type.

FIG. 14 schematically shows a cross section corresponding to one pixel 13 of the image sensor 12. This image sensor 12 is manufactured using the image sensor of the electronic blackboard 2 of the second embodiment. That is, the light shielding layers 76 and 7
After the formation of 7, a transparent insulating layer 79 is formed using SIO ₂ for planarization of the surface, and a color filter layer 80 is further formed on the surface. The color filter may be formed of a transparent dielectric, or may be formed by dyeing gelatin or dispersing a dye in a resin. When formed of a transparent dielectric, MgF ₂ , Si ₃ N ₄ or the like is used. The thickness of the transparent dielectric is adjusted for each pixel so that each of R, G, and B lights can be selectively transmitted.

The image sensor 12 and the image sensor of the electronic whiteboard 1 according to the first embodiment are different with respect to the reception of the ambient light, but are equivalent with respect to the light reception of the light source 16. Therefore, by performing the process of reading an image and generating image data by the method described with reference to FIG.

[0060]

According to the electronic blackboard of the present invention, it is possible to use the environmental light from the back side of the transparent substrate and the light source light from the front side of the transparent substrate. Reading as a bright image can be used properly.

By detecting environmental light incident from the back side of the transparent substrate with the image sensor, the written image shape is read, thereby reducing power consumption by the light source when only the image shape is required. Can be avoided.

Further, the color of the written image is read by detecting the light from the light source reflected by the written image with the image sensor, so that the color of the image can be read reliably. become.

When an optical member for switching between transmission and blocking of light is provided between the light source and the image sensor, the light source can be prevented from being seen by the user when the light from the light source is not used, and the appearance is improved.

If a diffusion plate for diffusing light is provided between the light source and the image sensor, the image can be illuminated with uniform brightness, and the density and color unevenness of the read image can be prevented. it can.

If the light source emits white light, a general light source can be used, so that maintenance is easy.

If the light source emits light of a plurality of colors, the color of the image can be read without switching the color of the light emitted by the light source and without providing other members such as a color filter.

When the image sensor is made of an inorganic material,
The electronic blackboard can read images stably for a long time.

When a light-transmitting protective film is provided on the back surface of the transparent substrate, it is possible to prevent the surface on which an image is recorded from being stained, and to write and read a high-quality image for a long period of time.

If a memory for storing the read image is provided, the user can use the image at any time after reading the image, which is convenient.

[Brief description of the drawings]

FIG. 1 is a front view and a rear view showing the appearance of an electronic blackboard of each embodiment.

FIG. 2 is a top view of an operation unit of the electronic blackboard of each embodiment.

FIG. 3 is a perspective view showing a part of a panel of the electronic blackboard according to the first embodiment;

FIG. 4 is a block diagram schematically showing the outline of the circuit configuration of the electronic blackboard of each embodiment.

FIG. 5 is a flowchart showing the flow of the entire image processing of the electronic blackboard of each embodiment.

FIG. 6 is a flowchart showing a flow of an image reading process on the electronic whiteboard according to the first, third, and fifth embodiments.

FIG. 7 is a cross-sectional view schematically showing a manufacturing process and a structure for one pixel of the image sensor of the electronic blackboard according to the first and third embodiments.

FIG. 8 is a perspective view showing a part of the panel of the electronic blackboard according to the second embodiment.

FIG. 9 is a flowchart showing a flow of an image reading process on the electronic blackboard according to the second and fourth embodiments.

FIG. 10 is a cross-sectional view schematically illustrating the structure of one pixel of the image sensor of the electronic blackboard according to the second and fourth embodiments.

FIG. 11 is a perspective view showing a part of a panel of an electronic blackboard according to a third embodiment.

FIG. 12 is a perspective view showing a part of a panel of an electronic blackboard according to a fourth embodiment.

FIG. 13 is a perspective view showing a part of a panel of an electronic blackboard according to a fifth embodiment.

FIG. 14 is a sectional view schematically showing the structure of one pixel of an image sensor of an electronic blackboard according to a fifth embodiment.

[Explanation of symbols]

 1, 2, 3, 4, 5 Electronic blackboard 10 Panel 11 Substrate 12 Image sensor 13 Pixel 13R, 13G, 13B Color filter 14 Photodiode 14R, 14G, 14B Color filter 15 Thin film transistor 16 Light source 16a Fluorescent tube 16R, 16G, 16B Light emission Diode 17 Liquid crystal shutter 18 Protective film 19 Diffusion plate 20 Output unit 21 Paper ejection port 22 Card insertion slot 23 Connector 24 Printing device 25 Card interface 26 External interface 30 Operation unit 31 Power button 32 Storage button 33 Copy button 34 Transmission button 35 Function button 36 input button 37 liquid crystal display 40 support frame 51 CPU 52 ROM 53 RAM 61 light shielding layer 62 transparent dielectric layer 63 gate electrode layer 64 insulating layer 65 gate layer 6 Source layer 67 Drain layer 68 Transparent electrode layer 69 Electrode connection layer 70 Photoelectric conversion layer 71 Electrode connection layer 72 Source electrode layer 73 Drain electrode layer 74 Wiring layer 75 Electrode layer 76 Light shielding layer 77 Light shielding layer 78 Insulating layer 79 Insulating layer 80 Color filter layer

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2C071 CA02 CA04 DA03 DC04 DC08 5B047 AA30 AB04 BB04 BC01 BC12 CA19 5C051 AA01 BA03 DA06 DB01 DB04 DB05 DB28 DC02 DC07 DE29 EA01 FA03 5C062 AA07 AB17 AE03 BA04

Claims (10)

[Claims] 1. An electronic blackboard having a transparent substrate and a two-dimensional image sensor provided on the surface of the transparent substrate, wherein at least a part of the image sensor is light-transmissive. An electronic blackboard comprising a light source for illuminating the transparent substrate from the front side of the transparent substrate. 2. The electronic blackboard according to claim 1, wherein the shape of the written image is read by detecting ambient light from the back side of the transparent substrate with an image sensor. 3. The electronic device according to claim 1, wherein a color of the written image is read by detecting light from a light source reflected by the written image with an image sensor. blackboard. 4. The electronic whiteboard according to claim 1, further comprising an optical member between the light source and the image sensor for switching between transmitting and blocking light. 5. The electronic blackboard according to claim 1, further comprising a diffusion plate for diffusing light between the light source and the image sensor. 6. The electronic blackboard according to claim 1, wherein the light source emits white light. 7. The electronic blackboard according to claim 1, wherein the light source emits light of a plurality of colors. 8. The electronic blackboard according to claim 1, wherein the image sensor is made of an inorganic material. 9. The electronic blackboard according to claim 1, further comprising a light-transmitting protective film on the back surface of the transparent substrate. 10. The electronic blackboard according to claim 1, further comprising a memory for storing the read image.