JPH08163313A - Close contact image sensor and led array used therefor - Google Patents

Abstract

PURPOSE: To allow one sensor to read an original with a dropout color and a usual original by selecting one of plural light sources with different emission colors and emitting the original by the selected light source. CONSTITUTION: In the close contact image sensor, either of a red LED array 1 and a yellow green LED array 2 emits an original 5 of a platen glass plate 4, a reflected light from the original 5 forms an image onto a linear image sensor 7 by an image forming lens 6 in a scale of 1:1. A signal used to select either the red LED array 1 or the yellow green LED array 2 is given from a connector 9 to a lighting control circuit on a printed circuit board 8. Then the lighting control circuit supplies power to the selected LED array and the light of the color component corresponding to the emitted color is reflected and the image of the original is subjected to photoelectric conversion.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact type image sensor used in an image scanner, a copying machine, an OCR or the like.

[0002]

2. Description of the Related Art A contact image sensor is one in which light from a light source is guided to the surface of an original, and the reflected light is imaged at an equal size on a linear image sensor and photoelectrically converted. . The feature is that the optical path length can be shortened compared to the one using the reduction optical system. As this light source, an LED array in which LED elements excellent in reliability and life are arranged in a straight line is used.

FIG. 7 shows a specific example of the above LED array. This LED array is mounted on a substrate 14 made of a rectangular flat plate having a long side in consideration of the document width, and is LE.
The number of D elements 15 and their intervals are defined so that the D elements 15 can uniformly illuminate a document with a sufficient amount of light, and the D elements 15 are mounted and fixed in a line. Each LED element 15 of this LED array is
It is an element that emits the same color, and is arranged on a center line connecting two opposing short sides of the substrate 14. Therefore, one LED array will provide a single color of light.

FIG. 8 shows a conventional contact image sensor using the LED array shown in FIG.
The contact image sensor according to this conventional example includes an LED array 1, a support 3, a glass 4 on which a document 5 is placed, an imaging lens 6, a linear image sensor 7, a substrate 8, and a connector 9. . The support 3 is composed of a pair of side plates that are bent upward and downward from the central portion, and the plates are joined to both side sides (front side and far side in the figure) of the side plates. The support 3 has a step inside the upper surface, and the glass 4 for setting the original 5 is buried and held in the step. The upper inner wall portion of the support 3 is 4 times larger than the glass 4.
It has slopes 3a and 3b which form 0 ° to 45 °.
The LED array 1 is fixed to a and 3b. Also support 3
Like the upper inner wall portion, the lower inner wall portion also forms a surface that widens outward as it approaches the bottom portion, and a chamber in which the linear image sensor 7 is installed is formed. The bottom of the support 3 is covered with a substrate 8 on which an electronic circuit is mounted, and a linear image sensor 7 is mounted on the substrate 8. Further substrate 8
A connector 9 for supplying electric power to the electronic circuit or taking out the output of the linear image sensor 7 is attached to this. On the other hand, the inside of the central portion of the two side plates forming the support body 3 is a space for installing the imaging lens 6, and the imaging lens 6 is located at a required position above the linear image sensor 7 in this space. Is installed. As described above, the LED array 1 used here emits a single color, and as is clear from the figure, the LED elements are arranged from the front side to the other side. In addition, the linear image sensor 7
Similarly, the photoelectric conversion element of is also linearly arranged from the front side to the other side.

In the contact type image sensor having such a configuration, L
The ED array 1 illuminates the original 5 on the glass 4, and the reflected light from the original 5 is imaged on the linear image sensor 7 by the imaging lens 6 at a ratio of 1: 1. And the original 5 is LE
The entire original is read by conveying it in the direction perpendicular to the D array 1 (direction of arrow X in FIG. 8). Further, the image of the document photoelectrically converted by the linear image sensor 7 is processed by an electronic circuit on the substrate 8 and output from the connector 9.

FIG. 9 shows an example of a signal waveform after being read by the linear image sensor 7 and processed by an electronic circuit on the substrate 8. The W part of the signal corresponds to the white of the original, and the D part of the signal
The part corresponds to black.

There are various colors such as red, orange, yellow, yellow-green, green, etc. as the light emitting color of the above LED array, and one LED array which emits a color suitable for the purpose is selected from these colors and is closely contacted. Mounted on the image sensor. For example, when it is necessary to read all the recorded information in a document, an LED array emitting yellowish green is mounted on the contact image sensor. This makes visible light (wavelength 39
Wavelength (570 nm) at the center of 0 nm to 770 nm
To obtain a high-luminance emission color of yellow-green. When it is necessary to properly read the imprint, an LED array that emits green light having a wavelength apart from the wavelength of the red color is mounted on the contact image sensor.

As compared with the case of reading the above-mentioned normal original,
You may not want to scan a part of the original. For example O
In the CR form, a character frame is printed and provided in advance so that the characters can be entered in a predetermined format. However, the character frame itself is meaningless as information and is the same as the color of the light source so that it can be read in a missing manner. Printed in color dropout colors. However, the background of the manuscript is white. This is because the color of the LED array and the color of the character frame are the same,
This is because light is reflected as in the case of white in the background.

An example of the OCR form is shown in FIG. In this example, the character frame K is printed in red, and the characters in the character frame K are black. When this form is illuminated using the red LED array, the character frame K is not read and the image information of the character "1" is obtained as shown in FIG.

[0010]

The light emitted from the LED element can be regarded as monochromatic light having a certain width with respect to the center wavelength due to its light emitting principle. Since the conventional contact-type image sensor is equipped with one LED array consisting of LED elements having one type of light emission color, it corresponds to the dropout color for a document with a dropout color and a normal document. L
It was necessary to prepare a contact image sensor equipped with an ED array and a contact image sensor equipped with an LED array corresponding to a normal document.

On the other hand, in order to cope with this with a single contact type image sensor, L is used for reading a normal original and for reading an original with dropout color.
It is necessary to replace the ED array, which is not realistic because of man-hours, time, and trouble. The present invention has been made to solve the problems of the conventional contact type image sensor described above, and an object thereof is to read both a document with dropout color and a normal document with a single device. It is to provide a contact image sensor that can be used. Still another object is to provide an LED array suitable for mounting on such a contact image sensor.

[0012]

Therefore, the contact type image sensor according to claim 1 of the present application includes an image sensor which converts light into an electric signal, and a plurality of light sources which respectively generate light of different colors. Light generated from multiple light sources
An optical system for reflecting an original document to form an image of the same size on the original document on the image sensor, a power supply for supplying light emission power to the plurality of light sources, and the power of the power supply for the plurality of light sources. The light source is selectively supplied to one light source, and the light source is used to generate light.

According to a second aspect of the present invention, in addition to the means constituting the contact type image sensor according to the first aspect, the light source includes a plurality of LED elements for generating a single color on a substrate. It is an LED array configured by arranging them individually, and is characterized in that a plurality of LED arrays are provided.

In the contact type image sensor according to claim 3 of the present application, in addition to the means constituting the contact type image sensor according to claim 1, the light source has LED elements for generating different single colors on the substrate. L arranged side by side
This is an ED array, and one or a plurality of this LED array is provided.

The contact type image sensor according to claim 4 of the present application has a constant current for each light source in addition to the means constituting the contact type image sensor according to any one of claims 1 to 3. A feature is that a constant current circuit for driving is provided.

According to a fifth aspect of the present invention, in addition to the means constituting the contact type image sensor according to any one of the first to fourth aspects, a contact type image sensor is provided with a predetermined portion of a predetermined document. It is characterized by comprising a light source that emits light of the same color.

The LED array according to claim 6 of the present application comprises:
A substrate for arranging LED elements, a plurality of LED element groups each generating a different single color, and LE for each color
And a power supply unit for supplying power to the D element group, wherein the plurality of LED element groups are arranged on the substrate.

[0018]

The contact type image sensor according to claim 1 of the present application can select any one of a plurality of light sources that generate light of different colors, and irradiate the original with the light of the selected light source. Then, the light of the color component corresponding to the emission color is reflected, and the image of the original is photoelectrically converted.

The contact type image sensor according to claim 2 of the present application is provided with a plurality of LED arrays each of which is formed by arranging a plurality of LED elements which generate a single color on a substrate.
One of the ED arrays is selected to emit light, the light of the selected light source is applied to the document, the light of the color component corresponding to the emission color is reflected, and the image of the document is photoelectrically converted.

In the contact type image sensor according to claim 3 of the present application, one or a plurality of LED arrays each of which is formed by arranging a plurality of LED elements each generating a different single color on a substrate are provided. An LED element that generates any one color is selected to emit light, the original light is irradiated with the light of the selected light source, the light of the color component corresponding to the emitted color is reflected, and the image of the original is photoelectrically converted. .

In the contact type image sensor according to claim 4 of the present application, the light source is driven by a constant current to suppress a change in the light emission amount due to the temperature characteristic of the light source.

According to a fifth aspect of the present invention, in the contact type image sensor, the light of a light source that emits light of the same color as a predetermined portion of a predetermined original is reflected by the original, and an image of the original that does not read the dropout color is photoelectrically converted. Convert.

The LED array according to claim 6 of the present application comprises:
Multiple LED element groups that emit multiple colors with one LED array and generate different single colors on the substrate,
Power is supplied in color units.

[0024]

1 is a sectional view of a contact type image sensor according to an embodiment of the present invention. This contact image sensor includes a red LED array 1 (center wavelength of 660 nm, half width of 30 nm) and a yellow-green LED array 2 (center wavelength of 570 nm).
nm, half width 30 nm), the support 3, the glass 4 on which the original 5 is placed, the imaging lens 6, and the linear image sensor 7
A substrate 8 and a connector 9. The support body 3 is composed of a pair of side plates each of which is bent upward and downward from the central portion, and both side sides thereof (front side and far side in the figure).
A plate is joined to the. The support 3 has a step portion 30 on the inside of the upper surface.
The glass 4 for setting the original 5 is embedded and held in the step portion 30. The upper inner wall portion of the support body 3 has an inclined surface 3 that makes an angle of 40 ° to 45 ° with the glass 4.
a and 3b, and the red LED array 1 is provided on the slope 3a.
However, the yellow-green LED arrays 2 are fixed to the slopes 3b. Further, the lower inner wall portion 31 of the support body 3 also forms a surface that widens outward as it approaches the bottom portion like the upper inner wall portion, and a chamber 32 in which the linear image sensor 7 is installed is formed. The bottom of the support 3 is covered with a substrate 8 on which an electronic circuit is mounted, and a linear image sensor 7 is mounted on the substrate 8. Further, the board 8 is provided with a connector 9 for supplying electric power to an electronic circuit or taking out an output of the linear image sensor 7. On the other hand, the support 3
The inside of the central portion of the two side plates constituting the
The image forming lens 6 is installed at a required position above the linear image sensor 7 in this space.

In the contact type image sensor having such a structure, one of the red LED array 1 and the yellow-green LED array 2 illuminates the original 5 on the glass 4, and the reflected light from the original 5 forms an image. An image is formed on the linear image sensor 7 by the lens 6 at a ratio of 1: 1. A signal for selecting one of the red LED array 1 and the yellow-green LED array 2 is given from the connector 9 to the lighting control circuit on the substrate 8. Then, the lighting control circuit supplies power to the selected LED array.

The electronic circuit mounted on the substrate 8 includes a lighting control circuit for selectively emitting one of the red LED array 1 and the yellow-green LED array 2. Figure 2
FIG. 3 is a block diagram showing the configuration of this lighting control circuit.
The selector 10 has an input terminal S and output terminals T and U.
The terminal S is connected to the connector 9. The red LED array 1 is connected to the terminal T via the constant current circuit 11. The yellow-green LED array 2 is connected to the terminal U via the constant current circuit 12. A control signal for selecting either the red LED array 1 or the yellow-green LED array 2 arrives at the connector 9 according to the operation of the light source color selection key on the operation panel (not shown). To the terminal S. When “L” is input to the terminal S, the selector 10 outputs “L” to the terminal T, the red LED array 1 is turned on, and when “H” is input to the terminal S, “L” is input to the terminal U. Is output, and the yellow-green LED array 2 is turned on. FIG. 3 shows a truth table when a control signal is input to the terminal S.

Constant current circuits 11, 1 used above
No. 2 is used in order to maintain a stable light emission amount by allowing a constant current to flow in consideration of the load variation due to the temperature characteristics of the LED array. The constant current circuits 11 and 12 have the same configuration, and an example thereof is shown in FIG. The input side of the photocoupler 13 is connected to the + 5V power source and the terminal T (U) via a resistor. The output side of the photocoupler 13 is -1 via a resistor.
Connected to 2V power supply and GND. The base of the transistor TR1 is connected to the collector of the phototransistor of the photocoupler 13. The collector of the transistor TR1 is connected to GND via a resistor. Transistor T
The emitter of R1 is connected to the -12V power supply. The Zener diode CD has an anode connected to the -12V power supply and a cathode connected to the collector of the transistor TR1. The non-inverting input terminal of the operational amplifier IC1 is connected to the anode and cathode of the Zener diode CD via resistors. The inverting input terminal of the operational amplifier IC1 is connected to a -12V power source via a resistor. The output terminal of the operational amplifier IC1 is connected to the base of the transistor TR2 via a resistor. The emitter of the transistor TR2 is connected to the inverting input terminal of the operational amplifier IC1. The cathode side terminal of the LED array 1 (2) is connected to the collector of the transistor TR2. The anode side terminal of the LED array 1 (2) is connected to GND via a resistor. Terminal T
The control signal input to (U) is at TTL level,
Since the circuit that drives the LED array is driven by a power supply of -12V, a photocoupler is used to isolate the two.

When "L" is input to the terminal T (U) of the circuit shown in FIG. 4, the photocoupler 13 is turned on, and the voltages B to E of TR1 are almost the same. Therefore, TR1 is turned off, and the Zener diode CD
A potential difference is generated between the anode and the cathode. With this potential difference as a reference, a voltage divided between GND and -12V by the resistor R1 is applied to the non-inverting input terminal of the operational amplifier IC1. Further, −12V is connected to the minus end of the resistor R, and the inverting input terminal of the operational amplifier IC1 is connected to the other end. The operational amplifier IC1 operates so that the voltage applied between the both input terminals becomes equal, and a stable potential difference is generated across the resistor R. Therefore, TR2 allows a stable load current I to flow even if the load of the LED array changes.

When "H" is input to the terminal T (U) of the circuit shown in FIG. 4, the photocoupler 13 is turned off. Therefore, TR1 is turned on, and the potential difference from -12V applied to the non-inverting input terminal of the operational amplifier IC1 becomes small. Therefore, the voltage drop across the resistor R is small, and the load current I is also small. Therefore, the amount of light emitted from the LED array is reduced.

By the above operation, when "L" is input to the terminal S, the red LED array 1 lights up and the yellow-green LED
Array 2 goes out. When "H" is input to the terminal S, the red LED array 1 is turned off and the yellow-green LED array 2 is turned on.

Next, as another embodiment, L on one substrate
FIG. 5 shows an example of an LED array capable of emitting a plurality of colors with the ED array. This LED array has LED elements 15, 16, 17 for emitting light of different colors on a substrate 14 made of a rectangular flat plate having long sides in consideration of the document width.
Are repeatedly arranged in the order of 15, 16 and 17 at equal intervals and are fixedly mounted in a line. Each of the LED elements forming this LED array is regulated in number and interval so that the original can be uniformly illuminated with a sufficient amount of light.
Are arranged on the center line connecting the two short sides facing each other. When reading three types of OCR forms that require different dropout colors of red, yellow, and blue, the LED elements 15, 16, and 17 are red, yellow, and blue LED elements, respectively.

A wiring diagram for each LED element is shown in FIG. The terminal 18 is a red LED sub array (a group of LED elements of the same color on the substrate 14 is a sub array), the terminal 19 is a yellow LED sub array, and the terminal 20 is a blue LE.
Connected to each D sub-array, the terminal 21 is LE of each color
The D sub-arrays are commonly connected. The LED array thus wired is provided with a switching section for selecting one of the terminals 18, 19 and 20 for supplying a current in accordance with, for example, the operation of the dropout color selection key so that the required LED sub-array emits light. . As a result, three types of OCR forms that require different dropout colors can be read. If more than three dropout colors are required, then use the required number of color LED sub-arrays.

As in the other embodiments, by mounting the LED sub-arrays of a plurality of colors on one substrate, the structure of the conventional contact image sensor can be used as it is.
We can provide a compact, low-price contact image sensor.

In the contact image sensor of the embodiment shown in FIG. 1, two LED arrays of different colors are mounted using the slopes 3a and 3b, but in another embodiment, for example, the slope is formed. By widely mounting two LED arrays that emit different lights on one slope, LED arrays of three or more colors may be mounted according to the two slopes. Further, the width of the LED array substrate is narrowed to mount two LED arrays on one slope, and to mount LED arrays of three or more colors on the two slopes. By doing so, it becomes possible to correspond to three or more dropout colors. Further, in the optical system of this embodiment, the light emitted from the light source is applied to the original as it is, and the reflected light from the original is imaged on the linear image sensor by the imaging lens. However, in other embodiments, the light from the light source is changed. Collect on the document surface with a condenser lens. In still another embodiment, the reflected light from the document is read by a linear image sensor which is extremely closely attached to the document without using an imaging lens. As described above, the present invention makes it possible to properly read a normal document and a document having a dropout color by one device in various apparatuses.

[0035]

As described above, the contact-type image sensor according to claim 1 of the present application is capable of selecting any one of a plurality of light sources each of which emits light of a different color. The original light is emitted to the original, the light of the color component corresponding to the emission color is reflected, and the image of the original is photoelectrically converted.Therefore, one device can use the color selected from multiple colors. The original can be read, which is advantageous in terms of installation location and price of the device.

In the contact type image sensor according to claim 2 of the present application, a plurality of LED arrays each of which is formed by arranging a plurality of LED elements for generating a single color on a substrate are provided.
Since one of the ED arrays is selected to emit light, the light of the selected light source is applied to the document, the light of the color component corresponding to the emission color is reflected, and the image of the document is photoelectrically converted. , Excellent in reliability and life.

In the contact image sensor according to claim 3 of the present application, one or a plurality of LED arrays each having a plurality of LED elements that generate different single colors are arranged on a substrate, and the LED array is provided. An LED element that generates any one color is selected to emit light, the original light is irradiated with the light of the selected light source, the light of the color component corresponding to the emitted color is reflected, and the image of the original is photoelectrically converted. Therefore, it is excellent in terms of reliability and life, and the structure of the conventional contact image sensor can be used as it is, and a small and low-priced device can be provided.

In the contact image sensor according to claim 4 of the present application, the light source is driven by a constant current to suppress the change in the amount of light emission due to the temperature characteristics of the light source, so that it is not affected by the load fluctuation.
A stable amount of light can be obtained.

According to a fifth aspect of the present invention, in the contact type image sensor, the light of a light source that emits light of the same color as a predetermined portion of a predetermined original is reflected by the original and the image of the original that does not read the dropout color is photoelectrically converted. As it is converted, it can be used for reading OCR forms.

The LED array according to claim 6 of the present application is
Multiple LED element groups that emit multiple colors with one LED array and generate different single colors on the substrate,
Power is supplied on a color-by-color basis, so it is excellent in terms of reliability and life, and can emit multiple colors in a compact size.

[Brief description of drawings]

FIG. 1 is a sectional view of a contact image sensor according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a lighting control circuit that selects and lights the red LED array 1 or the yellow-green LED array 2.

FIG. 3 is a truth table when a control signal is input to a terminal S of the selector 10.

FIG. 4 is a circuit diagram showing an example of constant current circuits 11 and 12.

FIG. 5 is a diagram showing an example of an LED array capable of emitting a plurality of colors with an LED array on one substrate.

6 is a wiring diagram for each LED element of the LED array of FIG.

FIG. 7 is a diagram showing a structure of an LED array used in a contact image sensor.

FIG. 8 is a sectional view of a conventional contact image sensor.

FIG. 9 is a diagram showing an example of a signal waveform when the linear image sensor 7 reads a document 5.

FIG. 10 is a diagram showing an example of an OCR form having a character frame that should not be read.

11 is a diagram showing information obtained by reading the OCR form shown in FIG. 10 using a red LED array.

[Explanation of symbols]

1 Red LED array 2 Yellow green LE
D array 3 support (3a, 3b slope) 4 glass 5 original 6 imaging lens 7 linear image sensor 8 substrate 9 connector 10 selector 11 red LED array lighting constant current circuit 12 yellow green LED array lighting constant current circuit 13 photo Coupler 14 Substrate 15 Red LED element 16 Yellow LE
D element 17 Blue LED element 18 Red LE
D sub-array + terminal 19 Yellow LED sub-array + terminal 20 Blue LE
D sub-array + terminal 21 LED array-terminal 30 Support 3
Step part 31 Lower part inner wall part 32 of support body 3 Support body 3
Chamber TR1 transistor TR2 transistor CD Zener diode IC1 operational amplifier R resistance

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masanori Kunimune, 3-1, Asahigaoka, Hino City, Tokyo 21 Toshiba Communication Technology Co., Ltd. (72) Inventor Tatsuo Soejima 1368 Taio-cho, Kohoku-ku, Yokohama, Japan Japan Business Computer Co., Ltd.

Claims (6)

[Claims] 1. An image sensor for converting light into an electric signal, a plurality of light sources each generating light of a different color, and light emitted from the plurality of light sources reflected by an original document. An optical system for forming a double image on the image sensor, a power source for supplying light emission power to the plurality of light sources, and a power source for selectively supplying the power of the power source to any one of the plurality of light sources. A contact type image sensor, comprising: a selection unit configured to generate light by one light source. 2. The light source is an LED array configured by arranging a plurality of LED elements that generate a single color on a substrate, and the plurality of LED arrays are provided. The contact image sensor described. 3. The light source is an LED array configured by arranging a plurality of LED elements each generating a different single color on a substrate, and one or more LED arrays are provided. The contact image sensor according to claim 1. 4. The contact type image sensor according to claim 1, wherein a constant current circuit for performing constant current driving is provided for each light source. 5. The contact image sensor according to claim 1, further comprising a light source that emits light of the same color as a predetermined portion of a predetermined document. 6. A substrate on which LED elements are arranged, a plurality of LED element groups each generating a different single color, and a power supply unit for supplying power to each of the plurality of LED element groups. And an LED array in which the plurality of LED element groups are arranged on the substrate.