JP2539478Y2 - Document reading device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a document reading device, and more specifically, to a document reading device.
Reduction of flare light in image reading scanner, S / N
The present invention relates to a document reading apparatus for improving the ratio, improving the gradation, and reducing the size.

Prior Art FIG. 13 is a cross-sectional view for explaining a conventional example of an image reading apparatus according to the present invention, in which 41 is a housing,
42 is a light source for illumination comprising a light emitting diode (LED) with a bar lens, 43 is a document holding member, 44 is an imaging optical element, 45 is a sensor, 46 is a light source room, 47 is a sensor room, 48 is a sensor drive circuit, Or a part thereof, 49 is an original, and 50 is a press roller.

The document 49 is conveyed on a transparent document holding member 43 by a pressing roller 50 rotating in the direction of arrow R, and the information on the document 49 is illuminated by a light source 42 and is formed by the imaging optical element 44 as light density information. The light is spatially transmitted and received by a sensor 45 composed of a photoelectric conversion element, and the information is read as an electrical output corresponding to the light density information of the document 49.

Here, as the light source 42, a light emitting diode (LED) array light source, a fluorescent lamp, a xenon tube, or the like is used. In the configuration of FIG. 13, a light emitting device with a bar lens in which a bar-shaped lens is arranged on an LED chip is used. A diode is used as a light source. Further, as the imaging optical element 44, a 1: 1 imaging element such as a rod lens array or a roof mirror lens array is used. As the photoelectric conversion element, a line sensor such as a charge coupled device (CCD) is used. A flat glass contact glass or the like is used as the document holding member 43 if necessary. In the conventional examples described below and the embodiments of the present invention, the photoelectric conversion element is referred to as a sensor.

In such a component, the illumination light source is disposed obliquely with respect to the original surface, and is therefore illuminated from the oblique direction with respect to the original surface. At this time, the arrangement of the imaging elements is such that specularly reflected light of the light source does not enter the entrance pupil with respect to the document surface. The reason is that the specularly reflected light is such that the image of the light source itself is reflected on the document surface irrespective of the density information of the document, reaches the sensor, and is taken in as noise for an effective information symbol. This light generally becomes flare light and raises the ground level when the original is black or when there is no original, and causes a decrease in the performance of the image reading apparatus such as a decrease in the SN ratio and a decrease in gradation. The conventional image reading apparatus adopts a configuration in which the specular reflection light of the light source 42 does not enter the optical system as described above and reduces flare light, so that the specular reflection light of the contact glass or the original enters the optical system. Although not provided, the amount of light reflected on the inner wall of the holding member of the scanner itself, that is, the inner wall of the light source room 46 and the sensor room 47 provided in the housing 41 of the image reading device, enters the optical system as stray light, resulting in flare. There was a problem that light was generated.

FIGS. 11 and 12 show the previously proposed actual application No. 58.
It is a figure for demonstrating the "reading apparatus" described in the specification of -6258. In FIG. 11, in the figure, 30 is a substrate, 31
Is a Dach mirror lens array, 32 is a multi-lens array,
33 is a multi roof mirror array, 34 is an illumination light source, 35 is a photo element, 36 is a light shielding layer, 37 is a light shielding film, 38 is a housing, and 39 is a document feeding direction.

On one surface of the substrate 30, that is, on a space facing the surface on which the illumination light source 34 is disposed, a roof mirror lens array 31 including a multi-lens array 32 and a multi roof mirror array 33 is disposed to constitute an optical system, Covered by housing 38. In this example, a wear-resistant light-shielding film 37 is further formed so as to cover the substrate 30 and the photoelement 35 closer to the photoelement 35 than the light-shielding layer 36. When reading the original image, the original is fed and moved in the direction indicated by the arrow so as to slide on the upper surfaces of the substrate 30 and the light shielding film 37. During the document feeding process, light transmitted through the slit of the illumination light source 34
The light transmitted through 30 is illuminated on the document located on the object surface on the substrate, and the reflected light is transmitted through the roof mirror lens array 31 to form an image on the photo element 35, and the image is read.

FIG. 12 is a view showing another embodiment. In the figure, reference numeral 40 denotes a plane mirror, and other portions having the same functions as those in FIG. 11 are denoted by the same reference numerals.

A substrate 30 having the same configuration as that of the above example and its accompanying members, that is, an illumination light source 34, a photo element 35, a light shielding film 37, and the like are used.

However, the optical axis direction of the roof mirror lens array 31 is set parallel to the substrate 30 unlike the above example, and a plane mirror 40 is used as an optical system, and the plane mirror 40 is tilted on the illumination light source 34. The document image is set so that the document image reaches the photo element 35 via the roof mirror lens array 31.

As described above, the conventional example shown in FIGS. 11 and 12 has a configuration in which the contact glass for holding the document is the same substrate as the sensor substrate. With such a configuration, if the thickness in the glass substrate is at most about 1 mm, which is a thickness that can withstand the pressure of the pressing roller, it is difficult to uniformly form the light shielding layer in the thickness direction.

SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and in a document reading apparatus in which a reading position of a document reading apparatus and a reading sensor are adjacent to each other, stray light between the reading position and the sensor is prevented, and flare light is emitted. It is an object of the present invention to provide a document reading apparatus capable of reducing the number of documents.

In order to achieve the above object, the present invention provides (1) a retroreflective imaging element, an illumination light source, and information on a document surface illuminated by the illumination light source, which is spatially transmitted by the imaging element. It is composed of a photoelectric conversion element that converts the intensity of light into an electric signal, and a housing member that integrally holds them, and the side that reads information on the document surface and the photoelectric conversion element are on the same side with respect to the imaging element. In the placed document reading device, a first light-blocking member for preventing stray light disposed between the photoelectric conversion element and a document reading position in a conjugate positional relationship with the photoelectric conversion element; A second light blocking member for preventing direct light from entering the photoelectric conversion element and the imaging element; and (2) the first light blocking member and the housing member are integrated. Being done, more (3) the second light shielding member and the housing member are integrated,
(4) the first light shielding member and the second light shielding member are integrated with the housing member, or
(5) a retroreflective imaging element, an illumination light source, and a photoelectric conversion element for converting information on a document surface illuminated by the illumination light source into an electric signal based on the intensity of light spatially transmitted by the imaging element. A document reading device, comprising a housing member for integrally holding these, and a side for reading information on the document surface and a photoelectric conversion element arranged on the same side with respect to the imaging element; A holding plate integrating a contact glass and a substrate of the photoelectric conversion element for reading, a plurality of grooves having different directions are provided on the holding plate, and a light shielding member for preventing stray light is provided in the groove. In addition, (6) one of the light shielding members provided in the plurality of grooves is a light shielding member for preventing stray light that protrudes in the optical axis direction of the imaging element, and the other is the holding member. Light shielding to prevent diffused light in the plate It is obtained by being a timber. Hereinafter, an embodiment of the present invention will be described.

FIG. 1 is a block diagram for explaining an embodiment of a document reading apparatus according to the present invention, wherein 1 is a first light shielding member, 2 is a second light shielding member, 3 is an illumination light source, and 4 is an illumination light source. A housing member, 5 is a contact glass, 6 is a sensor substrate, 7 is a sensor (photoelectric conversion element), 8 is a protective cover, 9 is a sensor driving circuit board, 10 is a coupling member, and 11 is a lens array (L
A), 12 is aperture plate, 13 is roof mirror array (RMA), 14
Is a roof mirror lens array (RMLA).

Imaging elements, ie roof mirror lens array (RML
A) 14 is composed of a lens array (LA) 11, an aperture plate 12, and a roof mirror array (RMA) 13;
Make up 4. The information on the document surface illuminated by the illumination light source 3 is converted into an electric signal by the photoelectric conversion element 7 based on the intensity of light spatially transmitted by the imaging element 14.
The document is placed on the contact glass 5 and the information of the document reading position a is read. The sensor 7 is provided on a sensor substrate 6, which is covered with a protective cover 8. The sensor board 6 is connected to the sensor drive circuit board 9 via a connecting member 10. The housing member 4 is
The illumination light source 3, the imaging element 14, the contact glass 5, and the sensor 7 are integrally held. In this example,
The sensor drive circuit board 9 is provided outside the housing member 4, but may be provided inside the housing as in an embodiment described later. Sensor 7 provided on sensor substrate 6
And the document reading position 9 are arranged outside the optical axis of the imaging element 14 and at a conjugate position, and extend between the sensor substrate 6 and the contact glass 5 in the optical axis direction of the imaging element 14. The member prevents stray light and obtains a separated and effective imaging light flux.

The second light shielding member 2 is provided near the illumination light source so that the illumination light does not directly enter the imaging element 14 from the illumination light source. With such a configuration, flare light can be prevented. The reflection surfaces of the first light-shielding member and the second light-shielding member may be coated on both surfaces or one surface with a coating film having a low reflectance.

The housing member is made of metal or plastic,
As the illumination light source, a light emitting diode (LED), a fluorescent lamp, a rare gas discharge lamp (xenon tube), or the like is used.

FIG. 2 is a view showing a modification of FIG. 1. In FIG. 2, reference numeral 15 denotes a second light shielding member integrated with the housing member, and other portions having the same functions as those in FIG. Is attached. By integrally forming the second light shielding member 2 in FIG. 1 with the housing member 4, the labor for mounting the light shielding member is facilitated, and the positional accuracy and the mechanical strength are improved.

FIG. 3 is a view showing another embodiment of the present invention.
Is a first light-shielding member integrated with the housing member, and other portions having the same functions as those in FIG. 1 are denoted by the same reference numerals. In FIG. 3, the sensor drive circuit board 9 and the sensor 7 are arranged in the housing member 4 due to the configuration in which the first light shielding member is integrated with the housing member. In this case, plastic is used as the housing member.

FIG. 4 is a view showing a modified example of FIG. 3, in which both the first light shielding member 16 and the second light shielding member 15 are integrated with the housing member. It is also possible to apply a low-reflectance coating film to the reflection surface of the integrated light shielding member, as in the case of FIG.

FIG. 5 is a view showing still another embodiment of the present invention.
Reference numeral 17 denotes an original, reference numeral 18 denotes a pressing roller, reference numeral 19 denotes a resin protective film, and other portions having the same functions as those in FIG. 1 are denoted by the same reference numerals. By forming the contact glass 5 so as not to be perpendicular to the optical axis direction of the imaging element 14, the convex portion near the sensor in the embodiment shown in FIGS. This is an embodiment in which conveyance is possible. The sensor 7 provided on the sensor substrate 6 is covered with a resin protective film.

FIG. 6 is a view showing a modification of FIG. 5, in which the first light shielding member 16 and the second light shielding member 15 are integrated with the housing member 4, and the protective cover of the sensor 7 is also used as the housing member.
The sensor drive circuit board 9 is also housed in the housing.

FIG. 7 is a view showing still another embodiment of the present invention. In the figure, reference numeral 20 denotes a second light-shielding member having a reflection surface integrated with a housing member. The same reference numerals are given to the same parts.

The illumination light source 3 is different from the oblique arrangement as in the embodiment of FIGS. 1 to 6 in that it has an optical axis, for example, perpendicular to the optical axis direction of the imaging element. This arrangement
This is an extremely effective arrangement for eliminating the convex portions near the illumination light source. The second light shielding member 20 has a reflection surface 20a, and by arbitrarily changing the angle of the reflection surface 20a, without being limited to the arrangement of the illustrated illumination light sources,
It is possible to improve the degree of freedom of arrangement. The sensor is covered with a resin protective film, thereby eliminating the need for a protective cover. In the configuration of FIG. 7, the contact glass 5 and the sensor substrate 6 can be integrated with the same member. Also in this case, needless to say, the first light shielding member 1 is provided between the sensor substrate 6 and the contact glass 5.

FIG. 8 is a view showing a modified example of FIG. 7, and shows a second light shielding member integrated with the illumination light source 3. The second light shielding member can be realized by integrating the reflection member 3a with the illumination light source 3.

FIG. 9 is a view showing still another embodiment of the present invention. In the figure, reference numeral 21 denotes a mirror, and other parts having the same functions as those in FIG. 1 are denoted by the same reference numerals.

The illumination light source 3 and the mirror 21 are integrated, and the mirror 21 forms a mirror on the image forming element and the document surface side. The information on the document surface illuminated by the illumination light source 3 is reflected via the mirror 21, and the intensity of light spatially transmitted by the imaging element 14 is converted into an electric signal by the sensor 6 again via the mirror 21. It has a configuration. Also in this case, the first light shielding member is provided between the sensor substrate 6 and the contact glass, and the second light shielding member is provided near the illumination light source.

FIG. 10 is a view showing still another embodiment of the present invention, in which 22a and 22b are grooves, 23 is a glass plate for adjusting thickness, 24 is a holding plate, and the other operations are the same as those in FIG. The same reference numerals are given to the same parts.

A contact glass for reading information on the document surface and the sensor substrate are integrated to form a holding plate 24, and the holding plate 24
Are formed with a plurality of grooves 22a and 22b by a diamond cutter or an etching process. The groove 22a,
A light-blocking member provided in the groove 22b is a light-blocking member provided in the groove 22a for preventing stray light extending in a convex shape in the optical axis direction of the imaging element. Corresponding to the light shielding member. Further, the light shielding member provided in the groove 22b is mainly for preventing diffused light in the holding plate, and prevents the diffused light by a double structure together with the embedded portion of the light shielding member provided in the groove 22a. I have. Also, the groove 22b
A protective cover 8 for the sensor
May be provided, or a resin protective film (not shown) may be provided. The glass plate 23 for adjusting the thickness is for adjusting the thickness of the glass plate 23 for adjusting the optical path length with the sensor 7 provided on the holding member. When the sensor is formed directly on the contact glass, a glass plate for adjusting the thickness becomes unnecessary.

As described above, in FIGS. 1 to 10, various descriptions have been made based on the embodiments of the present invention, but combinations of the embodiments are also possible. For example, a combination (not shown) such as arrangement of the sensor drive circuit board inside and outside the housing, arrangement of the illumination light source, integration of the light shielding member with the housing member, and the like are also possible. Further, the sensor drive circuit can be provided in the sensor substrate. As described above, the present invention is not limited to the illustrated embodiment.

Effects As is apparent from the above description, according to the present invention, a first light shielding member for preventing stray light is provided between a photoelectric conversion element and a document reading position in a conjugate positional relationship with the photoelectric conversion element, In addition, since the second light-blocking member for preventing direct light from the illumination light source from being incident on the photoelectric conversion element and the imaging element is provided, flare light can be reduced, and the S / N ratio can be improved.
The gradation can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram for explaining an embodiment of a document reading apparatus according to the present invention, FIG. 2 is a diagram showing a modification of FIG. 1, and FIG. 3 is another embodiment of the present invention. FIG. 4, FIG. 4 is a diagram showing a modification of FIG. 3, FIG. 5 is a diagram showing still another embodiment of the present invention, and FIG. 6 is a diagram showing a modification of FIG. FIG. 7 is a view showing still another embodiment of the present invention, FIG.
The figure shows a modification of FIG. 7, and FIGS. 9 and 10
FIGS. 11 to 13 show still another embodiment of the present invention, for explaining a conventional example. 1... First light shielding member, 2... Second light shielding member, 3.
Illumination light source 4, housing member 5, contact glass 6, sensor board 7, sensor (photoelectric conversion element) 8, protection cover 9, sensor driving circuit board
10: coupling member, 11: lens array (LA), 12: diaphragm plate, 13: roof mirror array (RMA), 14: roof mirror lens array (RMLA).

Claims (6)

(57) [Scope of request for utility model registration] 1. A retroreflective imaging element, an illumination light source, and photoelectric conversion for converting information on a document surface illuminated by the illumination light source into an electric signal based on the intensity of light spatially transmitted by the imaging element. A document reading device, comprising a device and a housing member for integrally holding these components, wherein a side for reading information on a document surface and a photoelectric conversion device are arranged on the same side with respect to the imaging element. A first light-blocking member for preventing stray light disposed between the element and a document reading position conjugate with the photoelectric conversion element, and direct light from the illumination light source is supplied to the photoelectric conversion element and the image forming element. And a second light-blocking member for preventing light from entering the document. 2. An original reading apparatus according to claim 1, wherein said first light shielding member and said housing member are integrated. 3. The document reading apparatus according to claim 1, wherein said second light shielding member and said housing member are integrated. 4. The document reading apparatus according to claim 1, wherein said first light shielding member and said second light shielding member are integrated with said housing member. 5. A retroreflective imaging device, an illumination light source, and photoelectric conversion for converting information on a document surface illuminated by the illumination light source into an electric signal based on the intensity of light spatially transmitted by the imaging device. A document reading device, comprising a device and a housing member for integrally holding these, wherein a side for reading information on the document surface and a photoelectric conversion element are arranged on the same side with respect to the imaging element; And a translucent holding plate integrating the contact glass for reading the information and the substrate of the photoelectric conversion element, and a directionality between the photoelectric conversion element and the document reading position of the translucent holding plate. A groove is provided in the light-transmitting holding plate vertically, and a light-blocking member is provided in the groove to prevent stray light straying between the photoelectric conversion element and the document reading position through the light-transmitting holding plate. Features Document reader that. 6. A light-shielding member provided in one of the grooves is a light-shielding member for preventing stray light extending in a convex shape with respect to the optical axis direction of the image forming element. 6. The document reading apparatus according to claim 5, wherein the light-shielding member provided in the image reading device is a light-shielding member for preventing diffused light in the holding plate.