JPH0983727A - Contact image sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a light receiving means and also to attach closely a rod lens array to a substrate to reduce the thickness of the lens array. SOLUTION: A contact image sensor is provided with a light source, a 1st reflection means which receives the reflected light from an original 11 and refracts it, a rod lens array 16 which receives the image light signals from the 1st reflection means and focuses them, an infrared cut filter 25c which receives the image light signals from the array 16 and cuts the infrared rays, a 2nd reflection means which refracts the image light signals received from the filter 25c, and a light receiving means which converts the image light signals received from the 2nd reflection means into the electric signals. The filter 25c and the 2nd reflection means are formed into a unified cover glass 25. Then the filter 25c is placed against the array 16, and the 2nd reflection means is placed at a position separate from the array 16.

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.

[0002]

2. Description of the Related Art Conventionally, in a contact type image sensor used in an image scanner, an original is illuminated by a light source and reflected light is focused by a rod lens array,
An image is formed on the CCD light receiving element. FIG. 2 is a sectional view showing a first example of a conventional contact image sensor.

In the figure, 11 is a manuscript, 12 is the manuscript 1
1 is a fluorescent lamp as a light source for irradiating 1 in a line shape. The fluorescent lamp 12 is arranged parallel to the reading unit 11a of the original 11 and at an incident angle of 45 degrees with respect to the reading unit 11a. That is, the fluorescent lamp 12 is the original 11
Is irradiated at an angle of 45 degrees. In addition to the fluorescent lamp 12, a cold cathode tube, a hot cathode tube, an LED array or the like can be used as the light source.

Further, 13 is a protective glass which protects the contact type image sensor and also places the original 11 in close contact with the original, and 15 is arranged facing the original 11 at an angle of 45 degrees. It is a reflective mirror. The reflecting mirror 15
Receives the 0-degree reflected light from the reading section 11a of the original 11 as an image light signal and bends it. The reflecting mirror 15 is arranged so as to extend in a band shape in the depth direction in the drawing, and the image light signal is reflected in a flat shape.

Further, 16 is a rod lens array which is arranged in parallel with the original 11 and focuses the image light signal from the reflecting mirror 15, and 17 is an angle of 45 degrees with respect to the end face of the rod lens array 16. Reflecting mirrors that face each other and bend by receiving the image light signal from the rod lens array 16. The reflecting mirror 17 is also arranged so as to extend in a strip shape in the depth direction in the drawing, and the image light signal is reflected in a flat shape.

A plurality of 18 are arranged in the depth direction in the drawing, and CCD light receiving elements for receiving the image light signal from the reflecting mirror 17, accumulating it as electric charges and converting it into electric signals, and 19 are the CCD light receiving elements. This is a substrate for holding and arranging 18 in a line (see JP-A-59-21172). Next, the operation of the contact image sensor having the above configuration will be described.

First, when the fluorescent lamp 12 is turned on, a part of the slit light of the irradiation light of the fluorescent lamp 12 passes through the protective glass 13 in a line shape, and then the reading portion 11a of the original 11 is rotated at 45 degrees. Irradiate at an angle. Reading unit 11a for the document 11
In the above, the irradiation light of the fluorescent lamp 12 becomes diffuse reflection light corresponding to the density of the original 11. Then, the diffusely reflected light of 0 degrees in the reading unit 11a, that is, the reading unit 11a of the document 11 is read.
The diffusely reflected light reflected at an angle of 90 degrees with respect to
Is incident on.

The reflecting surface of the reflecting mirror 15 is located directly below the reading section 11a and forms an angle of 45 degrees with the original 11. Therefore, the incident angle of the reflecting mirror 15 is 45 degrees,
The image light signal is bent 90 degrees. That is, the image light signal is bent by the reflecting mirror 15, becomes parallel to the original 11, and is incident on the rod lens array 16. The rod lens array 16 is arranged parallel to the original 11 and receives light at 0 degree on the incident surface. Then, the image light signal focused by the rod lens array 16 is bent again by 90 degrees by the reflecting mirror 17 and is incident on the CCD light receiving element 18. Therefore, the reading unit 11 of the document 11
The image information in a is formed as an erecting equal-magnification image on the light receiving surface of the CCD light receiving element 18 as an image light signal.

The CCD light receiving elements 18 are arranged in a line on the substrate 19 so as to have the same reading width as the original 11, and convert the incident image light signal into an electric signal. FIG. 3 is a sectional view showing a second example of a conventional contact image sensor. In the figure, 11 is an original and 12
Is a fluorescent lamp as a light source for linearly irradiating the original 11. The fluorescent lamp 12 has a reading unit 11a for reading the original 11.
Are arranged in parallel with respect to and at an incident angle of 45 degrees with respect to the reading unit 11a.

Further, 13 is a protective glass which protects the contact type image sensor and also places the original 11 in close contact with the original, and 15 is arranged facing the original 11 at an angle of 45 degrees. It is a reflective mirror. The reflecting mirror 15
Receives the 0-degree reflected light from the reading section 11a of the original 11 as an image light signal and bends it. The reflecting mirror 15
Are arranged so as to extend in the depth direction in the drawing in a strip shape, and the image light signal is reflected in a planar shape.

Reference numeral 16 denotes a rod lens array which is arranged in parallel with the original 11 and focuses an image light signal from the reflecting mirror 15, and a plurality of 18 are arranged in the depth direction in the drawing to output the image light signal. A CCD light receiving element for receiving and accumulating as electric charges and converting it into an electric signal is a substrate for holding the CCD light receiving elements 18 arranged in a line. The C
A semi-cylindrical cover glass 25 is provided on the CD light receiving element 18 so as to extend in the depth direction in the drawing,
The light receiving element 18 is covered and protected. A transparent portion 25a is formed on the curved portion of the cover glass 25 on the side facing the rod lens array 16 (right half in the figure), and on the side distant from the rod lens array 16 (left half in the figure). The reflection plate 26 is attached to the outside or inside of the curved portion to form the reflection portion 25b.

Next, the operation of the contact type image sensor having the above structure will be described. First, when the fluorescent lamp 12 is turned on, a part of the slit light of the irradiation light of the fluorescent lamp 12 passes through the protective glass 13 in a line shape, and then the reading unit 1 of the original 11 is read.
Irradiate 1a at an angle of 45 degrees. In the reading section 11a of the original 11, the irradiation light of the fluorescent lamp 12 becomes diffuse reflection light corresponding to the density of the original 11. Then, the diffuse reflection light of 0 degrees in the reading unit 11a, that is, the diffuse reflection light reflected at an angle of 90 degrees with respect to the reading unit 11a of the document 11 again passes through the protective glass 13 as an image light signal and is reflected. It is incident on the mirror 15.

The reflecting surface of the reflecting mirror 15 is immediately below the reading section 11a and forms an angle of 45 degrees with the original 11. Therefore, the incident angle of the reflecting mirror 15 is 45 degrees,
The image light signal is bent 90 degrees. That is, the image light signal is bent by the reflecting mirror 15, becomes parallel to the original 11, and is incident on the rod lens array 16. The rod lens array 16 is arranged parallel to the original 11 and receives light at 0 degree on the incident surface. Then, the image light signal focused by the rod lens array 16 passes through the light transmitting portion 25 a of the cover glass 25, passes through the inside of the cover glass 25, and reaches the reflecting portion 25 b. Then, the image light signal is reflected by the reflecting plate 26 in the reflecting portion 25b.
Then, the light is again bent 90 degrees and is incident on the CCD light receiving element 18. Therefore, the image information in the reading section 11a of the document 11 is formed as an erecting equal-magnification image on the light receiving surface of the CCD light receiving element 18 as an image light signal.

The CCD light receiving elements 18 are arranged in a line on the substrate 19 so as to have the same width as the reading width of the original 11, and convert the incident image light signal into an electric signal. FIG. 4 is a sectional view showing a third example of a conventional contact image sensor. In the figure, 11 is an original and 12
Is a fluorescent lamp as a light source for linearly irradiating the original 11. The fluorescent lamp 12 has a reading unit 11a for reading the original 11.
Are arranged in parallel with respect to and at an incident angle of 45 degrees with respect to the reading unit 11a.

Numeral 13 is a protective glass which protects the contact image sensor and also places the original 11 in close contact with the original glass, and numeral 31 is arranged in parallel with the protective glass 13 and is provided between the substrate 19 and the substrate 19. It is an auxiliary substrate for mounting the rod lens array 16 so as to sandwich it. A semi-cylindrical glass 32 extending in the depth direction in the drawing is arranged at a position corresponding to the reading unit 11a on the lower surface of the auxiliary substrate 31. A transparent portion 32a is formed on the curved portion of the glass 32 on the side facing the rod lens array 16 (left half in the figure), and the curved portion on the side distant from the rod lens array 16 (right half in the figure). A reflection plate 33 is attached to the outside or inside of the reflection part 3 and
2b is formed.

Further, a slit hole 31a is formed on the auxiliary substrate 31 immediately below the reading section 11a, and the slit hole 31a connects the reading section 11a and the reflection plate 33 and serves as an optical path for taking in an image optical signal. . The reflector 33
Receives the 0-degree reflected light from the reading section 11a of the original 11 as an image light signal and bends it. Further, since the reflecting plate 33 is arranged so as to extend in a strip shape in the depth direction in the drawing, the image light signal is reflected in a flat shape.

The rod lens array 16 is arranged in parallel with the original 11 and focuses the image light signal from the reflection plate 33. Reference numeral 18 denotes a CCD light receiving element which is arranged in the depth direction in the drawing and receives an image light signal, accumulates it as an electric charge, and converts it into an electric signal.
The CD light receiving elements 18 are arranged in a line, and the substrate 19
Held by

A semi-cylindrical cover glass 25 extending in the depth direction in the drawing is provided on the CCD light receiving element 18.
Is provided to cover and protect the CCD light receiving element 18. A transparent portion 25a is formed on the curved portion of the cover glass 25 on the side facing the rod lens array 16 (the right half in the figure).
The reflection plate 26 is attached to the outside or inside of the curved portion on the side away from (the left half in the figure) to form the reflection portion 25b.

Next, the operation of the contact type image sensor having the above structure will be described. First, when the fluorescent lamp 12 is turned on, a part of the slit light of the irradiation light of the fluorescent lamp 12 passes through the protective glass 13 in a line shape, and then the reading unit 1 of the original 11 is read.
Irradiate 1a at an angle of 45 degrees. In the reading section 11a of the original 11, the irradiation light of the fluorescent lamp 12 becomes diffuse reflection light corresponding to the density of the original 11. Then, the diffuse reflection light of 0 degrees in the reading unit 11a, that is, the diffuse reflection light reflected at the angle of 90 degrees with respect to the reading unit 11a of the document 11 again passes through the protective glass 13 as an image light signal, and The light passes through the slit hole 31 a and is incident on the reflection plate 33.

The reflecting surface of the reflecting plate 33 is located immediately below the reading section 11a and forms an angle of 45 degrees with the original 11. Therefore, the incident angle of the reflector 33 is 45 degrees,
The image light signal is bent 90 degrees. That is, the image light signal is bent by the reflecting plate 33, becomes parallel to the original 11, and is incident on the rod lens array 16. The rod lens array 16 is arranged parallel to the original 11 and receives light at 0 degree on the incident surface. Then, the image light signal focused by the rod lens array 16 passes through the light transmitting portion 25 a of the cover glass 25, passes through the inside of the cover glass 25, and reaches the reflecting portion 25 b. Then, the image light signal is reflected by the reflecting plate 26 in the reflecting portion 25b.
Then, the light is again bent 90 degrees and is incident on the CCD light receiving element 18. In this case, the rod lens array 16 is
Conjugate length, that is, from the reading unit 11a to the CCD light receiving element 1
8 is located at the center of the optical path distance of the propagation of the optical image signal reaching 8. Therefore, the image information in the reading section 11a of the document 11 is formed as an erecting equal-magnification image on the light receiving surface of the CCD light receiving element 18 as an image light signal.

The CCD light receiving elements 18 are arranged in a line on the substrate 19 so as to have the same length as the reading width of the original 11, and convert the incident image light signal into an electric signal.

[0022]

However, in the conventional contact type image sensor, the rod lens array 16 generally has a thickness of 3 to 10 [mm], and CC
The thickness of the D light receiving element 18 is about 0.5 [mm], and CC
Since the distance between the light receiving surface of the D light receiving element 18 and the reflecting portion 25b of the cover glass 25, which is the bending point of the reflecting mirror 17 (FIG. 2), is 1 to 4.5 [mm], the first In the case of the example, C
If a cover glass (not shown) for protection is mounted on the CD light receiving element 18, the rod lens array 16 cannot be brought into close contact with the substrate 19, and the contact image sensor cannot be made thin.

If the cover glass is not attached, it is necessary to thicken the rod lens array 16 in order to protect the CCD light receiving element 18, or to mount the rod lens array 16 away from the substrate 19. In this case However, the contact image sensor cannot be thinned. In addition, in the second and third examples, when a light source that radiates infrared light, such as a fluorescent lamp 12, a hot cathode tube, or a cold cathode tube, is used as the light source for irradiating the document 11, the infrared light is emitted. The light is incident on the CCD light receiving element 18 while being included in the image light signal. Therefore, in order to propagate only a meaningful image light signal to the CCD light receiving element 18, in general, an infrared cut filter (not shown) that blocks only infrared light is arranged on the optical path through which the image light signal propagates. Has become. However, when the infrared cut filter is provided on the optical path, not only does the contact-type image sensor become thicker by the amount of the infrared cut filter, but also the infrared cut filter is provided so that the contact-type image sensor is mounted. Will be restricted.

The present invention solves the problems of the conventional contact type image sensor, can protect the light receiving means, and can adhere the rod lens array to the substrate to make it thinner. It is intended to provide a sensor.

[0025]

Therefore, in the contact type image sensor of the present invention, a light source for illuminating an original document, and a first reflecting means for receiving and bending the reflected light of the original document as an image light signal, Arranged in parallel with the original,
A rod lens array that receives and focuses an image light signal from the first reflecting unit, an infrared cut filter that receives an image light signal from the rod lens array and blocks infrared light, and the infrared cut filter And a light receiving means for receiving the image light signal from the second reflecting means and converting it into an electric signal.

Further, the infrared cut filter and the second reflecting means are formed on an integral cover glass, and the infrared cut filter is arranged on the side facing the rod lens array and is separated from the rod lens array. The second reflecting means is disposed on the open side.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a contact image sensor according to the first embodiment of the present invention. In the figure, 11 is an original, 12 is the original 11
It is a fluorescent lamp as a light source that irradiates in a line shape. The fluorescent lamp 12 is arranged parallel to the reading unit 11a of the original 11 and at an incident angle of 45 degrees with respect to the reading unit 11a. That is, the fluorescent lamp 12 illuminates the document 11 at an angle of 45 degrees. As a light source, a fluorescent lamp 1
In addition to 2, cold cathode tubes, hot cathode tubes and the like can also be used.

In this case, the contact type image sensor can be made thinner by making the tube diameter of the fluorescent lamp 12 smaller than the thickness of the rod lens array 16. The commonly used rod lens array 16 has a thickness of 4 [mm].
The tube diameter of the fluorescent lamp 12 is about 2 [mm], and the tube diameter of the fluorescent lamp 12 is about 2 [mm]. The fluorescent lamp 12 is arranged on the substrate 19. Then, in order to increase the irradiation of the document 11, the fluorescent film inside the fluorescent lamp 12 is opened in a slit shape to form an aperture structure, or is attached to a portion other than the irradiation portion on the outer periphery of the fluorescent lamp 12. It is also possible to use a reflector attached.

Reference numeral 13 is a transparent protective glass for protecting the contact type image sensor and for making the original 11 and the CCD light receiving element 18 as a light receiving means parallel to each other. Can be placed at. Then, for example, in a flat base type contact image sensor in which the document 11 is two-dimensionally read by moving the contact image sensor, the protective glass 13 is a casing of the contact image sensor. Attached to the section.

Therefore, when placing the original 11 in close contact with the protective glass 13, the contact type image sensor
The density of the original 11 on the surface brought into close contact with the protective glass 13 is read. In this case, the reading unit 11a of the document 11 is one main scanning line in the contact image sensor.
Further, reference numeral 15 is a reflecting mirror as a first reflecting means arranged on the substrate 19 so as to face the input section of the original 11 and the rod lens array 16 at an angle of 45 degrees. The reflecting mirror 15 is a reading unit 11a of the original document 11.
The reflected light of 0 degrees at is received as an image light signal and is bent. The reflecting mirror 15 extends in the depth direction in the drawing in a strip shape and is arranged in parallel with the rod lens array 16 and the reading section 11a, and the image light signal is reflected in a flat shape.

The rod lens array 16 is arranged in parallel with the original 11 and focuses the image light signal from the reflecting mirror 15 so that the reflected light of 0 degree in the reading section 11a is reflected by the CCD light receiving element 18. An erecting equal-magnification image is formed on the light receiving surface. Further, a plurality of the CCD light receiving elements 18 are arranged in a line shape so as to have the same length as the reading width of the original 11 and in the depth direction in the drawing, and receive the image light signal and accumulate as electric charges. Convert to electrical signal. The substrate 19 holds the CCD light receiving elements 18 arranged in a line. A circuit for driving the CCD light receiving element 18, a circuit for processing an electric signal converted by the CCD light receiving element 18, and the like are attached to the substrate 19 as necessary.

A semi-cylindrical cover glass 25 extending in the depth direction in the drawing is provided on the CCD light receiving element 18.
Is provided to cover and protect the CCD light receiving element 18. An infrared cut filter 25c is formed in the curved portion of the cover glass 25 on the side facing the rod lens array 16 (right half in the figure), and the side away from the rod lens array 16 (left half in the figure). A reflecting plate 26 as a second reflecting means outside or inside the curved portion of the
Is attached, and the reflection portion 25d is formed.

The infrared cut filter 25c has about 70
The cutoff wavelength band is from 0 to 800 nm, the light in the short wavelength band is transmitted, and the light in the long wavelength band is cut off. Infrared light is blocked. Therefore, since infrared light is not incident on the CCD light receiving element 18 while being included in the image light signal, only the meaningful image light signal is received by the CCD light receiving element 18.
Can be propagated to.

In the present embodiment, the reflection plate 26 is formed by pasting, but it may be formed by aluminum vapor deposition. Further, although the cover glass 25 has a semi-cylindrical shape in the present embodiment, it may have a triangular shape. Here, the contact-type image sensor includes a fluorescent lamp 12, a reflecting mirror 15, a rod lens array 16, a CCD light receiving element 18, a substrate 19, a cover glass 25, a reflecting plate 26, and an infrared cut filter 25c. The fluorescent lamp 12, the reflecting mirror 15, the rod lens array 16, the cover glass 25 and the CCD light receiving element 18 are held by the substrate 19, and the reflecting mirror 26 and the infrared cut filter 25c are held by the cover glass 25. .

Since the contact image sensor having the above structure has a shallow depth of focus, it is necessary to increase the mounting accuracy of each of the above-mentioned components mounted on the substrate 19. Therefore, the positional relationship between the components and the adjusting method will be described. First, the CCD light receiving element 18 is mounted on the substrate 19.
In this case, in order to increase the reading length, the CCD light receiving element 1
When a plurality of 8 need to be attached, each CCD light receiving element 18 is placed on one line.

Second, the fluorescent lamp 12 is connected to the CCD light receiving element 1
Attach it in place so that it is almost parallel to 8. Thirdly, the rod lens array 16 is determined and the mounting position is calculated. In this case, the attachment position of the rod lens array 16 is determined by the conjugate length set for each rod lens array 16, that is, the optical path length from the reading section 11a of the original 11 to the CCD light receiving element 18, and the target color wavelength. Center wavelength band, thickness of protective glass 13, and cover glass 25
The rod lens array 16 will be located approximately at the center of the conjugate length.

Fourth, the rod lens array 16 is connected to CC
It is mounted on the substrate 19 so as to be parallel to the D light receiving element 18 and at the calculated mounting position. Fifth
Then, the reflecting mirror 15 is attached. In this case, the reflecting mirror 15
Are previously supported at 45 degrees with the input section of the rod lens array 16 and the substrate 19. In addition, the rod lens array 16 depends on the input viewing angle.
It does not require a 45 degree angle of 5.

Sixth, the cover glass 25 is brought into close contact with the substrate 19 and temporarily placed to protect the CCD light receiving element 18. In this way, after setting the positions of the respective components, the operation for performing optical adjustment is started. Then, the optical adjustment is performed only by adjusting the angle with the cover glass 25 in close contact with the substrate 19. The CCD light receiving element 18
The drive circuit, the image processing circuit, and the like are connected in advance.

Next, the operation of the contact type image sensor having the above construction will be described. First, when the fluorescent lamp 12 is turned on, a part of the slit light of the irradiation light of the fluorescent lamp 12 passes through the protective glass 13 in a line shape, and then the reading unit 1 of the original 11 is read.
Irradiate 1a at an angle of 45 degrees. In this case, the refractive index of the glass causes a certain difference between the irradiation angle of the fluorescent lamp 12 and the incident angle of the reading unit 11a of the document 11, but this is not a problem in image reading.

Since the original 11 is a black-and-white recording medium or a color recording medium composed of blue, green and red (or yellow, cyan, magenta), the reading section 1 of the original 11 is used.
In 1a, the irradiation light of the fluorescent lamp 12 becomes diffuse reflection light corresponding to the density of the original 11. In the present embodiment,
Diffuse reflected light of 0 degrees in the reading unit 11a, that is, diffuse reflected light reflected at an angle of 90 degrees with respect to the reading unit 11a of the document 11 passes through the protective glass 13 again as an image light signal, and is reflected by the reflecting mirror 15. Is incident on.

The reflecting surface of the reflecting mirror 15 is immediately below the reading section 11a and forms an angle of 45 degrees with the original 11. Therefore, the incident angle of the reflecting mirror 15 is 45 degrees,
The image light signal is bent 90 degrees. That is, the image light signal is bent by the reflecting mirror 15, becomes parallel to the original 11, and is incident on the rod lens array 16. The rod lens array 16 is arranged parallel to the original 11 and receives light at 0 degree on the incident surface. Subsequently, the image light signal focused by the rod lens array 16 passes through the infrared cut filter 25c of the cover glass 25, passes through the inside of the cover glass 25, and the reflection portion 25d.
Leading to. The image light signal passing through the inside of the cover glass 25 is the one in which the infrared light is blocked by passing through the infrared cut filter 25c.

Then, the image light signal in the reflecting section 25d is bent again by 90 degrees by the reflecting plate 26, and the CCD signal is reflected.
It is incident on the light receiving element 18. In this case, the rod lens array 16 is located at the conjugate length, that is, at the center of the propagation optical path distance of the image light signal from the reading unit 11a to the CCD light receiving element 18. Therefore, the image information in the reading section 11a of the document 11 is formed as an erecting equal-magnification image on the light receiving surface of the CCD light receiving element 18 as an image light signal.

The CCD light receiving elements 18 are arranged in a line on the substrate 19 so as to have the same length as the reading width of the original 11, and convert the incident image light signal into an electric signal. In this way, since the reflecting portion 25d can be formed on the cover glass 25 itself for protecting the CCD light receiving element 18, the distance on the normal line between the original 11 and the substrate 19 can be shortened, and the close contact can be achieved. The type image sensor can be made thin. In this case, the thickness of the contact image sensor is about the same as that of the rod lens array 16 and the substrate 19.
Depends on the thickness of.

Further, since the infrared cut filter 25c can be formed on the cover glass 25 itself, it is not necessary to attach another infrared cut filter on the optical path. Therefore, the contact-type image sensor does not become thicker by the amount of the additional infrared cut filter, and the mounting of the contact-type image sensor is not restricted.

Since all the components of the contact type image sensor can be arranged on the substrate 19, the structure of the contact type image sensor can be simplified and the housing for mounting the optical parts is unnecessary. Become. Further, since the image forming position of the CCD light receiving element 18 can be adjusted by moving the cover glass 25 in the horizontal direction while being in close contact with the substrate 19, the image forming position can be easily adjusted. When the bending angle of the image light signal on the reflection plate 26 is smaller than 90 degrees, it becomes possible to form an image on the center of the CCD light receiving element 18, so that the degree of freedom of the cover glass 25 increases and It becomes easier to adjust the image position.

Next, a second embodiment of the present invention will be described. FIG. 5 is a sectional view of a contact image sensor according to the second embodiment of the present invention. In the figure, 11
Is a manuscript, and 12 is a fluorescent lamp as a light source for irradiating the manuscript 11 in a line shape. The fluorescent lamp 12 is arranged parallel to the reading unit 11a of the original 11 and at an incident angle of 45 degrees with respect to the reading unit 11a. That is, the fluorescent lamp 12 illuminates the document 11 at an angle of 45 degrees.
In addition to the fluorescent lamp 12, a cold cathode tube, a hot cathode tube or the like can be used as the light source.

In this case, the contact type image sensor can be made thinner by making the tube diameter of the fluorescent lamp 12 smaller than the thickness of the rod lens array 16. The commonly used rod lens array 16 has a thickness of 4 [mm].
The tube diameter of the fluorescent lamp 12 is about 2 [mm] because the tube diameter is about 2 [mm] before and after (thin one is about 2 [mm]). The fluorescent lamp 12 is arranged on the substrate 19. Then, in order to increase the irradiation of the document 11, a fluorescent film inside the fluorescent lamp 12 is formed into a slit shape to form an aperture structure, or a reflection plate to be attached to a portion other than the irradiation portion on the outer periphery of the fluorescent lamp 12 is provided. It can also be used.

Reference numeral 13 is a transparent protective glass for protecting the contact type image sensor and for making the original 11 and the CCD light receiving element 18 parallel to each other. be able to. Then, for example, in a flat base type contact type image sensor in which the original 11 is two-dimensionally read by moving the contact type image sensor, the protective glass 13 is attached to the casing of the contact type image sensor. To be

Therefore, when placing the original 11 in close contact with the protective glass 13, the contact-type image sensor is
The density of the original 11 on the surface brought into close contact with the protective glass 13 is read. In this case, the reading unit 11a of the document 11 is one main scanning line in the contact image sensor.
Reference numeral 31 is an auxiliary substrate which is arranged in parallel with the protective glass 13 and is attached so that the rod lens array 16 is sandwiched between the substrate 19 and the protective glass 13. A semi-cylindrical glass 32 extending in the depth direction in the drawing is arranged at a position corresponding to the reading unit 11a on the lower surface of the auxiliary substrate 31. An infrared cut filter 32c is formed on the curved portion of the glass 32 on the side facing the rod lens array 16 (left half in the figure), and on the side distant from the rod lens array 16 (right half in the figure). The reflection plate 33 as the first reflection means is attached to the outside or inside of the curved portion to form the reflection portion 32d.

The reflecting plate 33 receives the 0-degree reflected light from the reading section 11a of the original 11 as an image light signal and bends it. Further, since the reflecting plate 33 is arranged so as to extend in a strip shape in the depth direction in the drawing, the image light signal is reflected in a flat shape. The infrared cut filter 32c is
Approximately 700 to 800 [nm] is set as a cutoff wavelength band, light in a short wavelength band is transmitted, and light in a long wavelength band is cut off.
It can block infrared light.

In the present embodiment, the reflection plate 33 is formed by sticking, but it may be formed by aluminum vapor deposition. Further, although the glass 32 has a semi-cylindrical shape in the present embodiment, it may have a triangular shape. By the way, a slit hole 31a is provided on the auxiliary substrate 31 immediately below the reading portion 11a.
Is formed, and the slit hole 31a connects the reading unit 11a and the reflection plate 33 and serves as an optical path for taking in an image optical signal.

The rod lens array 16 is arranged in parallel with the original 11 and focuses the image light signal from the reflecting mirror 33 so that the reflected light of 0 degree at the reading section 11a is reflected by the CCD light receiving element 18. An erecting equal-magnification image is formed on the light receiving surface. Further, a plurality of the CCD light receiving elements 18 are arranged in a line shape so as to have the same length as the reading width of the original 11 and in the depth direction in the drawing, and receive the image light signal and accumulate as electric charges. Convert to electrical signal. The substrate 19 holds the CCD light receiving elements 18 arranged in a line. A circuit for driving the CCD light receiving element 18, a circuit for processing an electric signal converted by the CCD light receiving element 18, and the like are attached to the substrate 19 as necessary.

A semi-cylindrical cover glass 25 extending in the depth direction in the drawing is provided on the CCD light receiving element 18.
Is provided to cover and protect the CCD light receiving element 18. An infrared cut filter 25c is formed in the curved portion of the cover glass 25 on the side facing the rod lens array 16 (right half in the figure), and the side away from the rod lens array 16 (left half in the figure). A reflecting plate 26 as a second reflecting means outside or inside the curved portion of the
Is attached, and the reflection portion 25d is formed.

The infrared cut filter 25c has about 70
The cut-off wavelength band is from 0 to 800 [nm], the light in the short wavelength band is transmitted, and the light in the long wavelength band is cut off. Infrared light can be blocked. In the present embodiment, the reflection plate 26 is formed by pasting, but it may be formed by aluminum vapor deposition. Further, although the cover glass 25 has a semi-cylindrical shape in the present embodiment, it may have a triangular shape.

Here, the contact image sensor includes a fluorescent lamp 12, a glass 32, a rod lens array 16, a CCD light receiving element 18, a substrate 19, a cover glass 25, and a reflector 2.
6 and 33 and infrared cut filters 25c and 32c. Then, the fluorescent lamp 12 and the rod lens array 1
6, the cover glass 25 and the CCD light receiving element 18 are held by the substrate 19, the reflecting plate 26 and the infrared cut filter 25c are held by the cover glass 25, and the reflecting plate 33 and the infrared cut filter 32c are the glass 32.
Held by

Since the contact image sensor having the above structure has a shallow depth of focus, it is necessary to increase the mounting accuracy of each of the above-mentioned components mounted on the substrate 19. Therefore, the positional relationship between the components and the adjusting method will be described. First, the CCD light receiving element 18 is mounted on the substrate 19.
In this case, in order to increase the reading length, the CCD light receiving element 1
When a plurality of 8 need to be attached, each CCD light receiving element 18 is placed on one line.

Second, the fluorescent lamp 12 is connected to the CCD light receiving element 1
Attach it in place so that it is almost parallel to 8. Thirdly, the rod lens array 16 is determined and the mounting position is calculated. In this case, the attachment position of the rod lens array 16 is determined by the conjugate length set for each rod lens array 16, that is, the optical path length from the reading section 11a of the original 11 to the CCD light receiving element 18, and the target color wavelength. Center wavelength band, thickness of protective glass 13, and cover glass 25
The rod lens array 16 will be located approximately at the center of the conjugate length.

Fourth, the rod lens array 16 is replaced with CC
It is mounted on the substrate 19 so as to be parallel to the D light receiving element 18 and at the calculated mounting position. Fifth
Then, the glass 32 is attached. In this case, the glass 32
Is attached in close contact with the auxiliary substrate 31 in advance. The rod lens array 16 does not require the angle of 45 degrees of the reflection plate 33 depending on the input viewing angle.

Sixth, the cover glass 25 is brought into close contact with the substrate 19 and temporarily placed to protect the CCD light receiving element 18. In this way, after setting the positions of the respective components, the operation for performing optical adjustment is started. Then, the optical adjustment is performed only by adjusting the angle with the cover glass 25 in close contact with the substrate 19. The CCD light receiving element 18
The drive circuit, the image processing circuit, and the like are connected in advance.

Next, the operation of the contact type image sensor having the above structure will be described. First, when the fluorescent lamp 12 is turned on, a part of the slit light of the irradiation light of the fluorescent lamp 12 passes through the protective glass 13 in a line shape, and then the reading unit 1 of the original 11 is read.
Irradiate 1a at an angle of 45 degrees. In this case, the refractive index of the glass causes a certain difference between the irradiation angle of the fluorescent lamp 12 and the incident angle of the reading unit 11a of the document 11, but this is not a problem in image reading.

Since the original 11 is a black-and-white recording medium or a color recording medium composed of blue, green, and red (or yellow, cyan, and magenta), the reading section 1 of the original 11 is used.
In 1a, the irradiation light of the fluorescent lamp 12 becomes diffuse reflection light corresponding to the density of the original 11. In the present embodiment,
Diffuse reflected light of 0 degrees in the reading unit 11a, that is, diffuse reflected light reflected at an angle of 90 degrees with respect to the reading unit 11a of the document 11 passes through the protective glass 13 again as an image light signal, and the slit hole is formed. It passes through 31 a and is incident on the reflection plate 33.

The reflecting surface of the reflecting plate 33 is directly below the reading section 11a and forms an angle of 45 degrees with the original 11. Therefore, the incident angle of the reflector 33 is 45 degrees,
The image light signal is bent 90 degrees. That is, the image light signal is bent by the reflection plate 33, becomes parallel to the original 11, and passes through the infrared cut filter 32c. Therefore, the image light signal in which the infrared light is blocked by the infrared cut filter 32c enters the rod lens array 16.

The rod lens array 16 is arranged in parallel with the original 11 and receives light at 0 degree on the incident surface. Subsequently, the image light signal focused by the rod lens array 16 passes through the infrared cut filter 25c of the cover glass 25, passes through the inside of the cover glass 25, and reaches the reflection section 25d. The image light signal passing through the inside of the cover glass 25 is the one in which the infrared light is blocked by passing through the infrared cut filter 25c.

Then, the image light signal at the reflecting portion 25d is bent again by 90 degrees by the reflecting plate 26, and CC
It is incident on the D light receiving element 18. In this case, the rod lens array 16 is located at the conjugate length, that is, at the center of the propagation optical path distance of the image light signal from the reading unit 11a to the CCD light receiving element 18. Therefore, the image information in the reading section 11a of the document 11 is formed as an erecting equal-magnification image on the light receiving surface of the CCD light receiving element 18 as an image light signal.

The CCD light receiving elements 18 are arranged in a line on the substrate 19 so as to have the same length as the reading width of the original 11, and convert the incident image light signal into an electric signal. It should be noted that the present invention is not limited to the above-described embodiments, and various modifications can be made based on the spirit of the present invention, and they are not excluded from the scope of the present invention.

[0066]

As described above in detail, according to the present invention, in the contact type image sensor, the light source for irradiating the original document and the reflected light of the original document are received as the image light signal and bent. Reflecting means, a rod lens array arranged in parallel to the original, for receiving and focusing the image light signal from the first reflecting means, and a red lens array for receiving the image light signal from the rod lens array. An infrared cut filter for blocking external light, a second reflecting means for receiving and bending an image light signal from the infrared cut filter, and an electric signal for receiving the image light signal from the second reflecting means Light receiving means for converting into.

Further, the infrared cut filter and the second reflecting means are formed on an integral cover glass, and the infrared cut filter is arranged on the side facing the rod lens array and is separated from the rod lens array. The second reflecting means is disposed on the open side. In this case, the infrared cut filter and the second reflection means are made of an integral cover glass, and the infrared cut filter is formed on the curved portion on the side facing the rod lens array, and is separated from the rod lens array. The second reflecting means is formed on the side curved portion.
Therefore, the image light signal from the rod lens array passes through the infrared cut filter, and then enters the reflecting section.

As described above, since the infrared cut filter and the second reflecting means can be formed on the cover glass itself for protecting the light receiving means, a method between the original and the substrate on which the light receiving means is mounted is provided. The distance on the line can be shortened, and the contact-type image sensor can be thinned. Further, since the infrared cut filter can be formed on the cover glass itself, it is not necessary to attach another infrared cut filter on the optical path. Therefore, the contact-type image sensor does not become thicker by the amount of the additional infrared cut filter, and the mounting of the contact-type image sensor is not restricted.

Further, since the image forming position of the light receiving means can be adjusted by moving the cover glass in the horizontal direction while being in close contact with the substrate, the image forming position can be easily adjusted. When the bending angle of the image light signal on the reflection plate is smaller than 90 degrees, an image can be formed in the center of the light receiving means, so that the degree of freedom of the cover glass is increased and the image forming position is adjusted. Will be easier.

[Brief description of drawings]

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

FIG. 2 is a sectional view showing a first example of a conventional contact image sensor.

FIG. 3 is a cross-sectional view showing a second example of a conventional contact image sensor.

FIG. 4 is a sectional view showing a third example of a conventional contact image sensor.

FIG. 5 is a sectional view of a contact image sensor according to a second embodiment of the present invention.

[Explanation of reference numerals] 11 original 12 fluorescent lamp 15 reflecting mirror 16 rod lens array 18 CCD light receiving element 25 cover glass 25c, 32c infrared cut filter 26, 33 reflector 32 glass

Claims (2)

[Claims] 1. A light source for irradiating an original, (b) first reflecting means for bending the light reflected by the original as an image light signal, and (c) arranged in parallel with the original. Was set up,
A rod lens array that receives and focuses the image light signal from the first reflecting means; (d) an infrared cut filter that receives the image light signal from the rod lens array and blocks infrared light; ) Second reflecting means for receiving and bending the image light signal from the infrared cut filter, and (f) light receiving means for receiving the image light signal from the second reflecting means and converting it into an electric signal. (G) The infrared cut filter and the second reflection means are formed on an integral cover glass, and the infrared cut filter is disposed on the side facing the rod lens array. A contact-type image sensor, characterized in that a second reflecting means is provided on the remote side. 2. (a) An infrared cut filter is provided between the first reflecting means and the rod lens array,
(B) The infrared cut filter and the first reflecting means are formed of an integral glass, the infrared cut filter is arranged on the side facing the rod lens array, and the infrared cut filter is provided on the side away from the rod lens array. The contact image sensor according to claim 1, wherein the first reflecting means is provided.