JP5901471B2 - Image reading device - Google Patents

Description

  The present invention relates to an image reading apparatus used for a copying machine or the like.

  There are roughly two types of image reading apparatuses that are used in copiers, scanners, facsimiles, and the like and read an entire image by scanning an image at a reading position using a one-dimensional image sensor. In general, the direction in which the one-dimensional imaging elements are arranged is called a main scanning direction, and the scanning direction is called a sub-scanning direction.

  One of the two types is a method of reducing and transferring the entire image in the main scanning direction onto the image sensor with a monocular lens, and is mainly used for reading the front surface in a copying machine. Yes. In this method, the image pickup element and the lens positioned on the document side are usually fixed, only the mirror is moved in the sub-scanning direction, and the entire document is scanned. In this method, since the focal depth (called depth of field) on the original side is as large as several millimeters, for example, 6 mm, the original can be read even if the original is not in close contact with the original reading surface of the copier. There are advantages. For example, this method has been mainly used for reading the front side of a copier because it has the advantage of being able to read without being out of focus even when it cannot be brought into close contact with the original surface, such as a book binding. It was. There are various patent documents derived from this method. For example, Patent Document 1 is cited (referred to as Conventional Method 1).

  The other of the above two methods is a method of dividing an image in the main scanning direction into a plurality of images and reading the image with a compound eye lens, and is usually called a contact image sensor. This method is used for a back side reading of a copying machine, a facsimile original reading, a banknote recognition sensor, a scanner for a personal computer, and the like, and is characterized by a small size. For example, Patent Document 2 discloses a conventional technique that is currently mainstream as an optical system of the contact image sensor. Here, as a compound eye lens (rod lens array in the literature), an array of a plurality of rod lenses having a refractive index distribution defined by a certain function in the radial direction is used. An image reading apparatus for obtaining an image is disclosed (referred to as Conventional Method 2).

  As another example of a typical system in the optical system of the contact image sensor, there is a system disclosed in Patent Document 3, for example. In this method, an image of a region corresponding to a cell is reduced and transferred by a lens provided for each cell divided in the main scanning direction, and formed on an image sensor. The image on the original surface is restored by synthesizing the output signals of the image sensors installed in each cell (referred to as conventional method 3).

  Patent Document 4 discloses a method similar to the conventional method 2 or the conventional method 3, but obtains an erecting equal-magnification image using a compound eye mirror lens array (referred to as the conventional method 4). .

  In Patent Document 5, the reading area is divided into odd-numbered areas and even-numbered areas, and the optical path of the imaging optical system is changed at the odd-numbered and even-numbered areas. A method of obtaining an erecting equal-magnification image on the surface has been disclosed (referred to as Conventional Method 5).

  In addition, the present applicant has proposed an image reading apparatus having a large depth of field in Patent Document 6.

JP-A-10-308852 Japanese Patent Laid-Open No. 8-204899 JP-A-5-14600 JP-A-11-8742 JP-A-2005-37448 JP 2009-246623 A

  The conventional method 1 has an advantage that the depth of field is large as described above, but there is a problem that the optical system becomes large. Further, in order to prevent the optical path from the document surface to the lens from changing when the mirror is moved, it is necessary to control the moving speed of a plurality of mirrors in the middle of the optical path. There is a problem.

  Although the conventional method 2 has the merit of being small and low cost, there are a problem that the depth of field is small and a problem that the chromatic aberration is large.

  Regarding the conventional method 3, when the depth of field is increased, the size of the apparatus increases, the problem that chromatic aberration increases, and the transfer magnification varies depending on the depth of field. When combining these images, there is a problem in that there is a mismatch in image overlay. Therefore, the depth of field cannot be increased.

  The conventional method 4 has an effect that there is no chromatic aberration because a mirror array in which a plurality of concave mirrors are arranged is used as the imaging optical element. However, such a configuration in which the mirror arrays are arranged in a straight line cannot constitute a telecentric optical system in which the image transfer magnification is unchanged even when the distance from the contact glass to the original is changed. This is because, in a telecentric optical system, concave mirrors having an aperture area larger than the field of view of one imaging unit system (called a cell) are required. However, since the concave mirrors are adjacent to each other, the aperture areas of the concave mirrors are necessary. This is because it cannot be made larger than the arrangement pitch of the concave mirrors.

  As described above, in the conventional method 4, since a telecentric optical system cannot be configured, the image transfer magnification in one cell changes depending on the distance from the contact glass to the original. As a result, the overlapping methods of adjacent images obtained from each cell are different. Therefore, the image at the array boundary is deteriorated, and a large depth of field cannot be obtained.

  In the conventional method 5, an image is read from an oblique direction with respect to a linear object using an odd-numbered area imaging system and an even-numbered area imaging system. For this reason, if the position of the object in the focal direction changes, the reading position changes between the odd-numbered area imaging system and the even-numbered area imaging system, and the two images are shifted on the photosensitive medium that is the imaging surface. There is a problem of end. Further, in the specification of Patent Document 5, there is no description regarding a specific configuration and effect of a telecentric imaging system. Therefore, when the position of the object in the focal direction changes, the transfer magnification at the focal position may change, and the way in which images are superimposed between the integer m-th and m + 1-th imaging systems is different, and the image is different. It will deteriorate. Due to these two problems, it is difficult for the conventional method 5 to obtain a large depth of field.

  The present applicant has already proposed an image reading apparatus that solves the above-described problems and has a large depth of field (WO2009 / 122483). That is, as shown in FIG. 28, the image reading apparatus 180 has folding mirrors 111 and 113 in the middle of the optical path. Since the optical path from the document 7 is folded back in the horizontal direction by the folding mirror 111, there is an advantage that it is easy to secure a space for installing illumination under the top plate 3. That is, when the optical path is folded back 90 degrees by the folding mirror 111, the distance from the top plate 3 to the folding mirror 111 can be set as an installation space for illumination. However, since the folding mirrors 111 and 113 are provided, there is a concern that the number of parts increases and the assembly accuracy may decrease. There are also concerns about the following two problems with the obtained image.

The first problem due to the presence of the folding mirrors 111 and 113 is due to the surface accuracy of the plane of the folding mirror 111. If the surface is distorted, the imaging position may deviate from the design position and distortion may occur. .
The second problem is that the obtained image rotates due to the attitude angle error of the folding mirrors 111 and 113 with respect to the light beam.

  This image rotation will be described with reference to FIG. The light rays are emitted in the −Z direction from the points 112a, 112b, 112c,... On the straight line 132, deflected and reflected in the direction of 90 degrees by the folding mirror 111A, and reach the screen 140. The passing point and the reaching point of the light beam on the folding mirror 111A and the screen 140 are 113a,..., 114a,. Let straight lines 133 and 134 connect the passing points and the reaching points of the respective rays. Here, the bending mirror 111A has an inclined surface having an inclination angle of φ = 45 degrees. When the bending mirror 111A rotates θ around the Z axis in FIG. 29, the obtained image rotates θ ′ = θ. That is, if the bending mirror 111A rotates θ and assumes the posture indicated by 111B, on the mirror side, the light ray passing point 113a,... Changes to 115a, and the light ray reaching point on the screen 140 is 114a. ,... Changes to 116a,. Therefore, a straight line 136 connecting the arrival points 116 a of the light rays forms an angle θ with respect to the straight line 134. Thus, the attitude angle error of the folding mirror 111 is the rotation of the image on the screen. As shown in FIG. 30, when a light beam is deflected at an angle of approximately 90 degrees by a mirror having a slope of 45 degrees, a large image rotation occurs. The rotation of the image is a phenomenon that the image looks distorted. Further, such an image rotation phenomenon occurs due to a large oblique angle of incidence of light rays on the folding mirror, and the degree is small when it is close to normal incidence.

  Thus, even in the image reading device 180 having a large depth of field, the use of a mirror having a large incident angle may cause distortion in the resulting image due to manufacturing errors and installation errors. was there.

  The present invention has been made to solve the above-described problems, and has a large depth of field, is small, can suppress distortion in an obtained image, and can be easily assembled. An object is to provide an apparatus.

In order to achieve the above object, the present invention is configured as follows.
That is, an image reading apparatus according to one aspect of the present invention is a light source that irradiates light on a document, and an imaging optical system that focuses light reflected from the document by the light from the light source to form an image. The imaging optical system is composed of a plurality of cells, each of which is an independent optical system. The plurality of cells are arranged along the main scanning direction, and are arranged in the sub-scanning direction perpendicular to the main scanning direction. An imaging optical system arranged in two rows of one row and a second row, and the cells in the first row and the second row are arranged in a staggered manner in the main scanning direction, and the respective cells A plurality of image sensor units that receive light that has passed through the cell and that correspond to each other in the sub-scanning direction, a memory that stores image information of the original document sent by the image sensor units corresponding to each other in the sub-scanning direction, and the memory Adjacent so that the images in the area where the stored image information overlaps match An image reading apparatus having a processor for creating the image of the original by combining the image information between cells, and
Each of the cells includes first and second reflection-type condensing optical elements, a first plane mirror, and an aperture that reflect and collect light from the document, and from the document in the cell. These are arranged in the order of the first reflection type condensing optical element, the first plane mirror, the aperture, and the second reflection type condensing optical element in the traveling direction of the light toward the image sensor unit, and the aperture is A telecentric optical system is formed on the document side by being disposed at the rear focal position of the first reflective condensing optical element;
The first plane mirror is formed of an integral structure.

  According to the image reading apparatus in one aspect of the present invention, the cell, which is an independent optical system constituting the imaging optical system, includes the first reflection type condensing optical element, the first plane mirror, the aperture, and the second reflection type condensing. The optical elements are arranged in this order in the optical path from the document surface to the image pickup device section, and the aperture is arranged at the rear focal position of the first reflective condensing optical element. Forms a telecentric optical system on the document side. In addition, there is no mirror that bends the optical path between the document and the first reflective condensing optical element, or between the second reflective condensing optical element and the imaging element unit. Since the optical element and the second reflection-type condensing optical element are configured so that the incident angle is smaller than that of a conventional mirror that bends the optical path, it is possible to suppress the occurrence of distortion in an image due to manufacturing errors and installation errors. Can do.

  According to the image reading apparatus of one aspect of the present invention, a light source that irradiates light on a document and a telecentric imaging optical system on the document side are formed, and a plurality of columns in the main scanning direction are arranged in two rows in the sub-scanning direction. A cell in which the image information is arranged, an image sensor unit, a memory that temporarily stores image information, and a processing device that restores the stored image information. According to this configuration, since the reading area in the main scanning direction of the document is divided and the image is read by the plurality of cells, the image reading apparatus can be reduced in size. Furthermore, since cells are arranged in two columns in the sub-scanning direction and an image is obtained from the cells arranged in each column, an image between cells is generated without causing deterioration of an image obtained from cells arranged in the main scanning direction. Can complement each other. Therefore, a good image can be obtained. Furthermore, since each cell is a telecentric optical system on the document side, the depth of field can be increased.

  More specifically, the use of a telecentric optical system on the original side of each cell has the advantage that the image transfer magnification does not change even if the original moves in the focal direction. On the other hand, each cell is a telecentric optical system on the side of the document, so that the chief ray is on the optical axis in the ray bundle from the point near the end of the image range read by the cell (referred to as point E) to the entrance pupil of the cell. Parallel. Therefore, in order to make all the light bundles from the point E enter the optical system of the cell without causing vignetting, a lens having a larger aperture than the reading range of the document is required. If the cells are arranged in a line in the sub-scanning direction and arranged adjacent to each other in the main scanning direction, a blank is generated in the reading range at the boundary between the cells. On the other hand, when the aperture of the lens is adjusted to the reading width of one cell, there arises a problem that vignetting from the point E occurs.

Therefore, in the image reading apparatus of one embodiment of the present invention, cells are arranged in two rows in the sub-scanning direction.
Here, in order to facilitate understanding, numbers are assigned to the cells. Of the two columns arranged in the sub-scanning direction, the cells in the first column are n = 1, 3, 5,..., And the cells in the second column are n = 2, 4, 6,. The image reading apparatus according to the above aspect employs a configuration in which the opening of the cell is larger than the reading range of the cell. According to this configuration, even if a blank range that cannot be read occurs at a boundary between adjacent cells in one first column, that is, between the k-th and (k + 2) -th cells, an image of the blank range is generated. Can be read by the (k + 1) th cell in the other second column, and the images can be complemented.

  Further, as described above, in the image reading apparatus of one embodiment of the present invention, the principal rays from the original to each cell are parallel in the first row and the second row, so the distance from each cell to the original. Even if fluctuates, the position of the image in the main scanning direction with respect to the image sensor section does not change. Therefore, the image at the k-th and (k + 1) -th boundary portion of the combined image does not deteriorate.

In addition, if the installation angle of the first plane mirror is different for each cell, the reading position on the document surface and / or the optical axis angle varies between cells, and both cause variation, and image degradation occurs when images are combined. It can happen. Since the first plane mirrors belonging to the cells in the first row and the second row are formed as an integral structure, it is possible to suppress variations in reading position or optical axis angle on the document surface between the cells, or variations in both. Therefore, it is possible to provide a good image without image deterioration.
In addition, by forming the first plane mirror as an integral structure, it is possible to obtain an effect that the assembly of the image reading apparatus becomes easy, and it is possible to reduce the cost by reducing the number of parts.
As described above, according to the image reading apparatus of one embodiment of the present invention, the depth of field is large and the size can be reduced.

1 is a diagram illustrating a schematic configuration of an image reading apparatus according to a first embodiment of the present invention. It is a perspective view which shows schematic structure of the image reading apparatus shown in FIG. It is the figure which looked at the image reading apparatus shown in FIG. 1 from the sub-scanning direction. It is a perspective view for demonstrating the structure of the integral structure with which the image reading apparatus shown in FIG. 1 is equipped. It is a perspective view which shows the modification of the integral structure shown in FIG. It is a perspective view which shows another modification of the integrated structure shown in FIG. It is a perspective view which shows another modification of the integrated structure shown in FIG. It is a perspective view for demonstrating the structure of the integral structure shown in FIG. 7, (a) is a perspective view which shows a mirror board | substrate, (b) is a perspective view which shows a flame | frame. It is a figure for demonstrating the malfunction in the case of providing the structure similar to the image reading apparatus shown in FIG. It is a figure for demonstrating the malfunction in the case of providing the structure similar to the image reading apparatus shown in FIG. It is a figure for demonstrating the malfunction in the case of providing the structure similar to the image reading apparatus shown in FIG. FIG. 2 is a perspective view illustrating a schematic configuration according to an actual configuration of the image reading apparatus illustrated in FIG. 1. FIG. 2 is a cross-sectional view illustrating a configuration in a main scanning direction in the image reading apparatus illustrated in FIG. 1. FIG. 2 is a perspective view illustrating a configuration in a sub-scanning direction of the image reading apparatus illustrated in FIG. 1. It is a figure which shows an example of the arrangement | positioning state of the reading area on a top plate, and original image character information. It is a figure showing an example of arrangement | positioning of an image pick-up element part, and the imaged character image. It is a figure which shows an example of the character image information imaged and reverse-processed. FIG. 2A is a diagram illustrating a state in which a main document is read by a first row of cells provided in the image reading apparatus illustrated in FIG. 1, and FIG. 2B is a diagram illustrating a state in which the image reading apparatus illustrated in FIG. It is a figure showing a mode that the original document is read in two rows of cells. It is a figure which shows the structure of the light source with which the image reading apparatus shown in FIG. 1 is equipped. It is a figure explaining the light source shown in FIG. It is a top view of the image pick-up element board | substrate with which the image reading apparatus shown in FIG. FIG. 2 is a plan view illustrating a configuration of an imaging element unit provided in the image reading apparatus illustrated in FIG. 1. It is a figure which shows schematic structure of the image reading apparatus by Embodiment 2 of this invention. It is a figure which shows schematic structure of the image reading apparatus by Embodiment 3 of this invention. FIG. 25 is a perspective view illustrating a configuration of an integral member provided in the image reading apparatus illustrated in FIG. 24. It is a figure explaining rotation of an image when a mirror rotates as shown in FIG. 30 is a graph in which the incident angle φ of the light beam is taken on the horizontal axis, and the sensitivity as the ratio of the image rotation angle θ ′ to the rotation angle θ of the mirror shown in FIG. 29 is taken on the vertical axis. It is a perspective view which shows an example of a structure in the conventional image reading apparatus. It is a figure for demonstrating that the transfer position of the point located in a straight line carries out (theta) rotation by rotation (theta) of the mirror which bends an optical path 45 degree | times. It is a figure which shows reflection of the light ray in the mirror shown in FIG.

  An image reading apparatus according to an embodiment of the present invention will be described below with reference to the drawings. In each figure, the same or similar components are denoted by the same reference numerals.

Embodiment 1 FIG.
An example of the image reading apparatus 501 according to Embodiment 1 of the present invention will be described with reference to the drawings.
As will be described below, the image reading apparatus 501 of the first embodiment is configured by a light reflecting imaging optical system, and light from the reading region of the document is repeatedly reflected and is applied to the image sensor unit. It reaches. On the other hand, for ease of understanding and for convenience of description, in the following description of the system configuration of the image reading apparatus 501, the first lens 100, the second lens 102, and the like in the imaging optical system are, for example, as shown in FIG. The illustration and description will be made in the form of a lens in a refraction system.

First, the system configuration of the image reading apparatus 501 will be described with reference to FIGS.
The image reading apparatus 501 of the present embodiment is broadly provided with an imaging optical system 1, a light source 2, imaging element units 41, 42,..., A memory 5, and a processing device 6. In these components, the light source 2 is disposed in the vicinity of the document 7 which is an example of an object to be read, and the imaging optical system 1 is disposed so that the light reflected from the document 7 can enter. In addition, the image sensor 41 and the like are appropriately arranged. Such an image reading apparatus 501 reads an image of the document 7 along the main scanning direction (X direction) 211, and further scans the document 7 in the sub-scanning direction (Y direction) 212 orthogonal to the main scanning direction 211. Then, all images on the document 7 are read. Note that the document 7 is a read object such as a sentence, a document, or a photograph, or a read object such as a banknote, and is used as a basis for printing, authentication, or as an electronic file. Or equivalent. In FIG. 12, the document 7 is not shown for clarity.

  The document 7 is placed on the top plate 3 as a document placing member. The top plate 3 is made of a transparent body and is generally a glass plate. For example, the illumination light source 2 such as a fluorescent lamp or an LED is disposed at a position below the top 3 and does not interfere with the reading of the document 7 and is to be imaged 31, 32 existing at the reading position on the document 7. ,... Are irradiated with an illumination light beam 201. In FIG. 12, the light source 2 is disposed only on one side of the imaging optical system 1 in the sub-scanning direction 212, but is not limited thereto, and may be disposed on both sides.

  Here, the light source 2 will be described. FIG. 19 shows the structure of the light source 2. The light source 2 is roughly divided into a light guide 21 having an emission part 22 and a light scattering layer 25, an electrode part 26, and a light emission source 27, which are arranged at both ends in the longitudinal direction of the light source 2. The light guide 21 is disposed between the electrode unit 26 and the light emission source 27.

  The light scattering layer 25 is provided over substantially the entire length of the light guide 21, and is used to uniformly irradiate light from the entire light source 2 along the main scanning direction 211 from the emission portion 22 of the light guide 21. is there. In the present embodiment, the light emission source 27 includes LED chips that emit red (R), green (G), and blue (B) wavelengths, respectively. Therefore, as shown in FIG. 20, an R light source 27R, a B light source 27B, and a G light source 27G are installed in the electrode unit 26.

In addition, in order to make the light emission from the emission part 22 uniform, the light scattering layer 25 is formed with a wide center in the main scanning direction 211 when the light emitting sources 27 are installed at both ends of the light guide 21. In the case of installation on one side, the width is increased as the distance from the light source 27 increases. 20 shows the light scattering layer 25 in which the center in the main scanning direction 211 is formed wide.
Note that the optical wavelength of each RGB light source 27 is substantially the same as the wavelength of each RGB color of the RGB filter provided in the light receiving section 402 (FIG. 22) described below.

  In FIG. 12, the imaged parts 31, 32,... Are shown surrounded by a strip-shaped frame for ease of explanation and visual understanding, but there is no particular structure. For the sake of explanation, the portion where the imaged portions 31, 33,... Are arranged along the main scanning direction 211 is defined as a reading line 8, and the portion where the imaged portions 32, 34,. To do.

The imaging optical system 1 is an imaging optical system that condenses the scattered light of the illumination light beam 201 of the light source 2 reflected by the image pickup units 31, 32,. The imaging optical system 1 has a plurality of cells 11, 12,. Each of the cells 11, 12,... Is an independent imaging optical system, has a telecentric optical system on the side of the original 7, and a plurality of cells 11 are arranged in the main scanning direction 211.
Furthermore, in the sub-scanning direction 212, the cells 11, 12,... Are arranged in two columns, a first column 215 and a second column 216. Here, the cells 11, 13, 15,... Belong to the first column 215, and the cells 12, 14,. In addition, the cells arranged in the same row are arranged such that the light rays from the original 7 toward the cells 11, 12,... Of the principal rays, the word “light rays going from the document 7 to the cells 11, 12,...” Can be replaced with the term “optical axis”. That is, the cells 11, 13,... Are provided so that the optical axes 11a, 13a,... Of the cells 11, 13,. The cells 12, 14,... Are provided so that the optical axes 12a, 14a,.

  Further, in the first column 215 and the second column 216, the formed images can be complemented between the cells 11 and 12 in the sub-scanning direction 212, between the cells 12 and 13, between the cells 13 and 14,. The cells 11, 12, 13,... Are arranged in a staggered manner in the main scanning direction 211.

The arrangement and optical path of the optical system elements constituting each cell 11, 12, 13,.
FIG. 13 is a diagram showing the imaging optical system elements of the cells 11, 13, 15,... Provided in the first column 215 and the main optical path in the main scanning direction 211. FIG. 14 is a diagram showing imaging optical system elements and main optical paths in a state where the cells 11 and 12 are overwritten in the sub-scanning direction 212.

  Each cell 11, 12, 13,... Has the same configuration. Here, the cell 11 will be described as an example. The cell 11 holds a first lens 100 that is an example that functions as a first optical element, an aperture 101 that is an example that functions as a diaphragm, a second lens 102 that is an example that functions as a second optical element, and the like. And a holder 103. By arranging the aperture 101 at the rear focal position of the first lens 100 in the cell 11, the cell 11 can realize a telecentric optical system on the document 7 side.

  In the first embodiment, as shown in FIGS. 12 and 14, the optical axes 11 a, 13 a,... In the cells 11, 13,... Belonging to the first column 215, and the cells 12, 14 belonging to the second column 216. In the state where the optical axes 12a, 14a,... In the first row 215 and the second row 216 are inclined toward the gap side, the cells 11, 13,. 12, 14,... Are arranged. As a result, in the first embodiment, as shown in FIG. 14, the optical axes 11a and 12a of the document 7 placed on the top 3 cross each other. The optical axes 11a, 12a and the like of the both do not necessarily need to intersect at the upper surface of the top plate 3, but may intersect above the top plate 3.

  Next, the image sensor unit will be described. As shown in FIG. 12, the image sensor sections 41, 42,... Are arranged on the substrate 4 so as to correspond to the respective cells 11, 12, 13,. In other words, the image sensor sections 41, 43,... Are arranged corresponding to the cells 11, 13,... Belonging to the first column 215, and the image sensor sections 42 corresponding to the cells 12, 14,. , 44,... Are arranged.

With reference to FIG. 21 and FIG. 22, the image sensor unit will be described in more detail. FIG. 21 is a plan view of the substrate 4 including the image sensor units 41, 42,... 2a is a light source connection unit that electrically connects the illumination light source 2 and the connector 400 of the image sensor substrate 4. FIG.
Each of the imaging element units 41, 42,... Is configured by arranging a plurality of light receiving units made of, for example, a CCD or the like in the main scanning direction 211, and further arranging a plurality of the light receiving units in the main scanning direction 211. These are arranged in a plurality of rows in the sub-scanning direction 212.

  FIG. 22 is a plan view of the image sensor sections 41, 42,. The image sensor units 41, 42,... Roughly include a light receiving unit 402, a photoelectric conversion / RGB shift register driving circuit 403, and an input / output unit 404. The light receiving unit 402 is an image pickup element in which an RGB filter 402a made of gelatin material or the like made of red (R), green (G), and blue (B) is arranged on a light receiving surface for one pixel. In the imaging element unit 41 and the like, 144 light receiving units 402 corresponding to 144 pixels are arranged along the main scanning direction 211. The photoelectric conversion / RGB shift register drive circuit 403 photoelectrically converts the light incident on the light receiving unit 402 for each RGB, holds the output, and drives it. The input / output unit 404 is a wire bonding pad unit that inputs / outputs signals and power to / from the image sensor unit 41 and the like.

  In the imaging element units 41, 42,... Configured as described above, the original images incident on the cells 11, 12, 13,... Are captured by the first lens 100, the aperture 101, and the second lens 102. A reverse image is formed on the element portions 41, 42, 43. For example, the image of the imaged part 31 on the reading line 8 of the document 7 passes through the cell 11 and is imaged and imaged on the imaging element unit 41, and the image of the imaged part 32 on the reading line 9 passes through the cell 12. As shown in FIG.

The memory 5 is connected to the image sensor units 41, 42,... And stores image information sent from the image sensor units 41, 42,.
The processing device 6 reads the image information stored in the memory 5, restores it to the image, combines it, and creates the entire image on the document 7. The memory 5 and the processing device 6 are illustrated separately in FIG. 12, but can of course be installed on the same substrate.
The memory 5 and the processing device 6 will be described in detail in the following operation description.

  The imaging optical system 1 in the image reading apparatus 501 having the system configuration as described above is composed of a light reflecting optical system as described at the beginning. Hereinafter, an actual optical system configuration in the image reading apparatus 501 will be described with reference to FIGS. 1 to 3.

  Here, FIG. 1 is a diagram showing a cross section along the sub-scanning direction 212 in the image reading apparatus 501, from the original 7 in the one cell 11, 12, etc. to the image sensor 41, 42, etc. The actual optical path is shown. The first lens 100 and the second lens 102 correspond to an example of the function of the first reflection type condensing optical element and the second reflection type condensing optical element, respectively, and are constituted by a concave mirror, reflect.

  2 is actually in a state where the cells 11, 13,... Belonging to the first column 215 and the cells 12, 14,... Belonging to the second column 216 are arranged in a staggered pattern in the main scanning direction 211. FIG. The optical path is shown in a perspective view.

  FIG. 3 is a view of the configuration shown in FIG. 2 as viewed from the sub-scanning direction 212 along the main scanning direction 211. In order to make it easy to understand the overlapping of the light beams, the optical path from the aperture 101 to the image sensors 41 and 42 and the substrate 4 such as the image sensors 41 and 42 are not shown.

  As shown in FIG. 1, the image reading apparatus 501 has the following configuration. That is, the first lenses 100 and 100 are installed at positions corresponding to the reading lines 8 and 9 (FIG. 12) below the top plate 3 in the Z direction. Each first lens 100 reflects the light reflected by the reading lines 8 and 9 obliquely upward at an angle φ in a different direction in the sub-scanning direction 212. The angle φ is an angle formed between the optical axis 591 of the light beam from the reading lines 8 and 9 to the first lenses 100 and 100 and the optical axis 592 of the light beam reflected by the first lenses 100 and 100.

  As shown in FIG. 1, an integrated structure 600 in which a plane mirror and a window are integrally formed is disposed above the first lenses 100 and 100 in the Z direction. Therefore, each light reflected by the reading lines 8 and 9 passes through the window portion 601 in the integrated structure 600 and reaches the first lenses 100 and 100. The integrated structure 600 will be described in detail below.

  Each light beam reflected obliquely upward by the first lenses 100 and 100 is reflected by the plane mirror portion (referred to as the first plane mirror 105) in the integrated structure 600. The light beam reflected by the first plane mirror 105 passes through the apertures 101 and 101 and reaches the second lenses 102 and 102. Here, the apertures 101 and 101 are installed at the rear focal positions of the first lenses 100 and 100. The light beams reflected again in the Z direction by the second lenses 102 and 102 are image sensor elements 41, 43,... Corresponding to the cells 11, 13,... And the image sensor elements 42 corresponding to the cells 12, 14,. , 44,...

  Here, the second lens 102 and the image sensor elements 41 and 42 are shielded from the light source 2 by the partition wall 127, the aperture 101, and the substrate 4. Further, the substrate 4 is separated into a substrate 4a having image pickup element portions 41, 43,... And a substrate 4b having image pickup element portions 42, 44,. By separating the substrate 4 and adjusting the positions of the substrates 4a and 4b, the reading position of the document 7 can be adjusted separately corresponding to the cells 11, 13,... And the cells 12, 14,. There is an advantage that the variation of the reading position of the document 7 and / or the variation of the optical axis angle caused by the assembly error can be corrected. Note that “50” shown in FIG. 1 indicates electronic circuit components such as the image pickup element portions 41 and 42.

In the image reading apparatus 501 having the above-described configuration, the optical path in the imaging optical system 1 of the light reflected from the document 7 will be further described with reference to FIGS. 1 and 2.
Light rays traveling from the document 7 toward the cells 11, 12, etc. pass through the window portion 601 of the integrated structure 600, and their optical paths are bent and condensed by the first lens 100 that is a concave mirror. The light beam reflected by the first lens 100 is reflected by the first plane mirror 105 in the integrated structure 600 and passes through the aperture 101. Here, the optical path length from the first lens 100 through the first plane mirror 105 to the aperture 101 is set to be equal to the focal length of the first lens 100. Therefore, the image reading apparatus 501 is a telecentric optical system on the document surface side of the document 7. That is, chief rays incident on each cell 11 and the like from each point on the original surface along the main scanning direction 211 are parallel to each other. The light beam that has passed through the aperture 101 has its optical path bent and condensed by the second lens 102, which is a concave mirror, and is focused on the image sensor portions 41, 42, and the like.

  As shown in FIG. 1, in the image reading apparatus 501, the light is incident on the first lens 100 that is a concave mirror, the second lens 102 that is a concave mirror, and the first plane mirror 105 in the configuration in each of the cells 11 and 12. It is characterized in that the angle of each light beam is small. That is, in the image reading apparatus (WO2009 / 122483) already proposed by the present applicant described above with reference to FIG. 28, due to the use of a mirror having a large incident angle, the manufacturing error and the installation error are caused. In some cases, the obtained image may be distorted.

  On the other hand, in the image reading apparatus 501 in the present embodiment shown in FIG. 1, the oblique incident angle of the light beam to the first lens 100 made of a concave mirror is made smaller than that shown in FIG. In the present embodiment, the oblique incident angle of the light beam in the first lens 100 is about 10 degrees, which is very small compared to 45 degrees of the folding mirror 111 (FIG. 28). Similarly, the oblique incident angle of the light beam in the second lens 102 is about 10 degrees and is relatively small. Therefore, the rotation angle of the image due to the installation error of the first lens 100 and the second lens 102 is small. As described above, according to the image reading apparatus 501 of the present embodiment, by providing the first lenses 100 and 102 having a relatively small incident angle of light, two problems described below with reference to FIG. Generation of distortion and image rotation can be avoided.

  In order to make the above description concrete, the calculated model and the calculation result are shown in FIGS. 26 and 27 together with FIGS. 29 and 30 described above. As shown in FIG. 29, light rays are emitted in the −Z direction from points 112a, 112b, 112c,... On a straight line 132 parallel to the X axis, and enter the bending mirror 111A at an incident angle φ. As shown in FIG. 30, the reflected light is reflected in a direction away from the Z axis by an angle 2φ and reaches the screen 140. Here, when the bending mirror 111A rotates θ around the Z-axis and assumes the posture indicated by 111B, the image rotates θ ′ as shown in FIGS. The ratio of the image rotation angle θ ′ to the rotation angle θ of the bending mirror 111A is defined as the sensitivity of the image rotation phenomenon using the inclination angle φ of the inclined surface of the bending mirror 111A, that is, the incident angle φ of the light beam as a parameter. The graph is shown in FIG. As can be seen from FIG. 27, when the incident angle φ of the light beam is φ = 45 °, the sensitivity θ ′ / θ is 1. As described with reference to FIG. 29 and the rotation of the image in the prior art, φ = 45 °. This corresponds to θ ′ = θ. The smaller the incident angle φ of the light beam, the smaller the sensitivity. When φ = 30 °, the sensitivity becomes ½. In the example of the present embodiment, the oblique oblique angle of the light beam is about 10 degrees as described above. Thus, if the oblique incident angle of the light beam is set to 30 degrees or less, the rotation of the image can be reduced as compared with 45 degrees in the prior art. That is, it is possible to sufficiently obtain an effect that the rotation of the image due to the installation error of the first lens 100 and the second lens 102 is reduced.

  On the other hand, when the oblique incident angle on the concave mirror increases, a large aberration occurs due to the oblique incidence. In the case of a spherical mirror or an axially symmetric aspherical concave mirror, it is difficult to correct the aberration. Depending on the required resolution, the curved surface of the concave mirror is a free-form surface having different curvatures in the x and y directions in the surface, so that aberrations are largely removed and the resolution can be improved. The shape of this free-form surface is represented by the following equation, for example.

  Cx = 1 / Rx, Cy = 1 / Ry (Formula 2)

  X ’= X + Xoffset

  In this expression, the center of the opening of the concave mirror is the origin, and here the x direction is the sub-scanning direction and the y direction is the main scanning direction. In addition, the center of the opening is a position where the optical axis passes. z is the sag value of the concave mirror. The origin of the curved surface function (Equation 1) is offset from the center of the aperture by Xoffset. In this way, if the center position of the function is shifted from the optical axis passage position, aberration correction can be efficiently performed for obliquely incident light rays.

The first term in “Expression 1” represents a biconic surface having different curvatures in the x and y directions.
The third term in "Formula 1"

Since an optical system that is symmetrical with respect to the sign of y is assumed, odd-order coefficients such as β1, β3, β5, and β7 are zero.
Second term in "Formula 1"

  If the odd-order coefficient αi is a non-zero value, the curved surface shape is asymmetric with respect to the sign of X ′. By introducing this odd-order term, it becomes easy to remove aberration due to a large oblique incident angle.

  In this manner, by configuring the concave surfaces of the first lens 100 and the second lens 102 as free-form surfaces, it is possible to reduce aberrations even for light rays having a large incident angle and output angle of about 10 degrees.

The operation of the image reading apparatus 501 in the present embodiment configured as described above will be described below mainly with reference to FIGS. 1 and 12 to 18.
The illumination light beam 201 emitted from the illumination light source 2 irradiates the document 7 placed on the top 3.
The image of the reflected and scattered light from the imaged parts 31, 33, 35... Positioned on the reading lines 8, 9 of the document 7 is imaged by the cells 11, 13, 15. Images are taken by the units 41, 43, 45. Similarly, the reflected and scattered light from the imaged parts 32, 34, 36,... Is imaged by the cells 12, 14, 16,..., And the image sensor parts 42, 44, 46,. Imaged. At this time, the light ray actually reflects and passes through the first lens 100, the first plane mirror 105, the aperture 101, and the second lens 102 as described above. Image signals sent from the respective image sensor units 41, 43, 45,..., 42, 44, 46,... Are temporarily stored in the memory 5, and the image signals are restored by the processing device 6.

The operation of restoring the images obtained by the image sensor sections 41, 42, 43,... Corresponding to the cells 11, 12, 13,.
As shown in FIG. 14, each of the cells 11, 12,... Arranged in the first row 215 and the second row 216 has its optical axis inclined toward the gap in the sub-scanning direction 212. Depending on the position in the height direction (Z direction), the reading position is shifted in the sub-scanning direction. That is, the optical axes intersect on the top plate 3, but the optical axes are separated in the sub-scanning direction at a position 76 above the top plate 3. Therefore, the images captured by the cells 11, 13,... And the cells 12, 14,. In other words, images on the same line in the sub-scanning direction 212 are taken at different times. As described above, the images obtained by the image sensor units 41, 42, 43... Are temporarily stored in the memory 5 in order to restore the original document image from images captured at different times. Then, the original document image is restored by the processing device 6 from each temporarily stored image. An image processing operation for performing the above restoration when a reverse image is obtained as shown in FIGS. 13 and 14 will be described below with reference to FIGS.

  15 shows the arrangement of the imaged portions 31, 32, which are reading areas when the document 7 is placed at a position 76 (FIG. 14) above the top board 3, and a character image on the document 7 not shown. “A” is shown. In FIG. 15, a range AA ′ in the main scanning direction 211 is an overlapping region between the image capturing unit 31 and the image capturing unit 32, and a range B′B is an overlapping region between the image capturing unit 32 and the image capturing unit 33. is there. When the document 7 is scanned in the sub-scanning direction 212, the character image “A” is scanned in the Y direction as a relative positional relationship. Here, the term “relative positional relationship” indicates that the document 7 may be scanned in the sub-scanning direction 212 with respect to the stationary image reading apparatus 501, or the stationary document 7 may be scanned. This means that the image reading apparatus 501 may be scanned in the sub-scanning direction 212. Here, it is assumed that the character image “A” exists in an area extending between the imaged unit 31 and the imaged unit 32.

  FIG. 16 shows the image sensor portions 41, 42,... Arranged on the image sensor substrate 4. In FIG. 16, a range aa ′ in the main scanning direction 211 is an overlapping region between the imaging element unit 41 and the imaging element unit 42, and a range b′b is an overlapping region between the imaging element unit 42 and the imaging element unit 43. is there. When the signal image of the character image “A” obtained by the image sensor unit 41 and the image sensor unit 42 is schematically represented by taking the scan time on the vertical axis and the horizontal axis on the main scanning direction 211, a dotted line shown in FIG. As shown in the frame. The image obtained by the imaging element unit 41 is obtained by inverting the image in the imaged unit 31 in the main scanning direction 211 of the character image “A”. Similarly, the image obtained by the imaging element unit 42 is an inverted version of the image in the imaged unit 32 in the main scanning direction 211 of the character image “A”. Here, an image indicated by a portion corresponding to AA ′ and a portion corresponding to A′A in the drawing is an overlapping region of the imaging target portions. When the images obtained by the two image pickup device portions 41 and 42 are inverted, and the overlapping regions are horizontally aligned and vertically aligned, two images are drawn as shown in FIG. The original character image “A” can be obtained by combining the two images so that the images in the overlapping region of the two images match. The processing device 6 performs such a composition operation.

  Here, the advantages of performing the above-described image composition processing will be described. Regarding the method of converting images obtained from a plurality of imaging optical systems into erecting equal-magnification images and synthesizing images from adjacent imaging optical systems on the image sensor unit, the conventional methods 2, 4, 5 described above are used. It is stated in. However, it is not easy to assemble an optical element made up of mechanical elements such as a plurality of lenses and mirrors so that there is no deviation between the joint areas of images obtained from adjacent imaging optical systems.

On the other hand, as in the present embodiment, by adopting a method of restoring an original image obtained from each cell 11, 12... By image synthesis on signal processing, that is, by software, Even if a slight error occurs in the overlay of the image of the adjacent k-th cell and the (k + 1) -th cell due to manufacturing errors of at least one of the assembly and lens, the error can be easily done on the software. Can be corrected.
As described above, acquiring an independent image for each cell and performing image synthesis has an effect of reducing manufacturing errors.

  Next, taking a document 7 such as a book as an example, a configuration for obtaining a large depth of field, which is one of the features of the present invention, will be described with reference to FIG. The original 7 such as a book requires an image reading device having a large depth of field because the binding of the book rises from the top 3.

  As shown in FIG. 18, it is assumed that there is a document 7 whose position in the focal direction (Z direction) changes in the main scanning direction 211. 18A shows the cells 11, 13,... Belonging to the first column 215 and the optical paths in these cells 11, 13,... FIG. 18B shows the second column. The cells 12, 14,... Belonging to H.216 and the optical paths in these cells 12, 14,.

  As described above, each of the cells 11, 12, 13, 14,... Provided in the image reading apparatus 501 of the present embodiment is an optical system that is telecentric on the document 7 side. Therefore, the image reading apparatus 501 of the present embodiment is characterized in that the image reading position with respect to the image sensor unit does not change in the main scanning direction even if the object distance to the document 7 varies. That is, if image synthesis parameters are determined at the initial stage of assembly or at the initial stage of operation, an image can be superimposed in the main scanning direction even on a document 7 whose distance to the top 3 changes in the plane. There is an effect that no deviation occurs. Therefore, the correction in the image composition process is easy because only the shift in the sub-scanning direction 212 is required. The composition of the images between the adjacent cells may be performed by shifting the images in the sub-scanning direction 212 so that the images captured in the same region between the adjacent cells match.

  Therefore, the depth of field of the image reading apparatus 501 of the present embodiment is almost determined by the depth of field of the individual cells 11, 12, 13, 14,. The depth of field of each cell 11, 12, 13, 14,... Is determined by the design of the optical system in the cell. The depth of field is substantially determined by the F value of the optical system. In order to increase the field of view of one cell, it is necessary to sufficiently correct the aberration by making the lens in the cell an aspherical shape or using a plurality of lenses. If a resolution of 600 dpi is required, it is only a guide, but an F value of F = 10 can provide a depth of field of approximately ± 1 mm, and a depth of field of approximately ± 2 mm can be obtained at F = 20.

  In FIGS. 13, 14, and 18, the focus is on the top surface of the top plate 3, but this is not necessarily the case. For example, in the optical system of F = 10, if the top plate 3 is arranged so as to be focused on a surface 1 mm above the top surface of the top plate 3, a depth of field of ± 2 mm can be sufficiently used.

  The above describes the case where the optical axes of the cells belonging to the first row and the second row are inclined toward the gap, but the same configuration can be adopted even in a parallel configuration where the optical axes do not cross each other. it can. However, description of this parallel case is omitted here.

Next, the configuration and effect of the integrated structure 600 of the first plane mirror 105 and the window portion 601 described above, which is one of the characteristic configurations of the image reading apparatus 501 of the present embodiment, will be described.
As shown in FIG. 4, an integrated structure 600 of a plane mirror and a window includes, for example, the above-described first plane mirror 105 and window portion 601 on a flat glass substrate 603. For example, the first flat mirror 105 is formed by vapor-depositing aluminum on a glass substrate. In a region where mirror vapor deposition is not necessary, the first flat mirror 105 needs to be light-reflected as shown in FIG. Only a small area can be used as a mirror part.

  Since the intermediate region between the first plane mirrors 105, that is, the intermediate region in the Y direction, which is the sub-scanning direction 212, is a region through which light rays contributing to imaging pass, as can be seen from FIG. A window portion 601 is formed so that aluminum is not deposited. As shown in FIG. 4, an IR (infrared) cut filter can be applied to the window portion 601 or no IR cut filter can be provided as shown in FIG. The IR cut filter can be manufactured, for example, by depositing a dielectric multilayer film, and is for obtaining a good image by cutting near infrared light exceeding the visible range.

By using the integrated structure 600 of the plane mirror and the window, the following four great effects can be obtained.
As a first effect, the number of parts can be reduced. That is, the functions of the plurality of first plane mirrors 105 and the IR cut filter in the window portion 601 can be achieved by the integrated structure 600 alone, the number of parts can be reduced, and the cost can be reduced by the reduction. The assembly of the device is also easy.
As a second effect, downsizing can be achieved. That is, since the IR cut filter in the window 601 is integrated with the vapor deposition section having the function of the first plane mirror 105, a space for installing the IR cut filter can be reduced, and the entire product can be downsized. .
As a third effect, it is possible to prevent dust from entering. That is, by making the first plane mirror 105 and the window portion 601 into an integral structure by the integral structure 600, it is possible to prevent dust from entering the cells 11, 12, etc. In addition, it is possible to prevent image deterioration due to adhesion to the imaging element portions 41 and 42 and the like.
As a fourth effect, it is possible to prevent assembly variations. In order to explain this point, first, a problem that occurs when the first plane mirror 105 is mounted in a different manner will be described.

When the first plane mirror 105 is individually attached to each of the cells 11, 12,..., Reading on the document surface is performed for each cell 11, 12... Due to variation in at least one of the attachment angle of the first plane mirror 105 and the attachment position in the Z direction. Variations occur in the position, the angle of the optical axis, the transfer magnification of the image in the cells 11, 12,.
For example, as shown in FIG. 9, when the first plane mirror 105 is tilted and attached to the outside of the apparatus in the sub-scanning direction 212 (when rotating around the X axis), the angle of the optical axis with respect to the first plane mirror 105 falls outward. In addition, the imaged parts 31, 33,... On the document surface and the imaged parts 32, 34,. If the positions of the imaged parts 31 and 32 and the like are separated in the sub-scanning direction 212, as illustrated in FIG. 16, the image shift between adjacent cells increases, and the amount of memory for performing image composition increases. Problems arise.

  10, when the orientation of the first plane mirror 105 varies in the main scanning direction 211 (when the first plane mirror 105 rotates around the Y axis), the imaged parts 31, 32,. The angle of the optical axis with respect to the first plane mirror 105 varies along the main scanning direction 211. Due to such variation, as shown in FIG. 10, for example, if there is no overlapping area between the imaged part 31 and the imaged part 32 between adjacent cells, a missing image is formed. Further, when there are overlaps in the imaged parts 31, 32,... Between adjacent cells in the main scanning direction 211, and the angle of the optical axis in the main scanning direction 211 differs between adjacent cells, when the document distance changes, The image of the overlapping area between cells moves in the main scanning direction 211. Therefore, it is necessary to move the image in the main scanning direction 211 when performing the above-described image composition processing, which makes the image composition processing difficult.

  As shown in FIG. 11, when the position of the first plane mirror 105 is different from the design position 610 in the Z direction, the optical path length from the first lens 100 to the aperture 101 is different from the focal length of the first lens 100. As a result, it is no longer a telecentric optical system. For example, as shown in FIG. 11, when the first plane mirror 105 is above the design position 610, the principal rays 611 and 612 outside the field of view fall down inward as shown. That is, when the optical system is not a telecentric optical system, the transfer magnification changes according to the change in the document distance, and the image of the overlapping area between the cells moves in the main scanning direction 211, causing a deviation in the image overlay. Also in this case, the above-described image composition processing becomes difficult.

  The problems shown in FIGS. 9 to 11 can be solved by using the integrated structure 600 for the problems caused by the variation in the mounting of the first plane mirror 105 as described above. That is, since the first flat mirror 105 corresponding to the mirror portion is installed on the single flat glass substrate 603, variation in installation between the cells 11, 12,. In addition, since the tilt in the sub-scanning direction 212 is suppressed, variation in the angle between the imaging target in the sub-scanning direction 212 and the optical axis can be suppressed, and the problem described with reference to FIG. 9 can be solved. . Similarly, the variation in the inclination of the first plane mirror 105 in the main scanning direction 211 can be suppressed, whereby the variation in the angle between the imaging target portion and the optical axis in the main scanning direction 211 can be suppressed, and will be described with reference to FIG. Can be solved. Further, since the positions of the first plane mirrors 105 in the Z direction are aligned, the problem that the transfer magnification changes for each of the cells 11, 12,. Furthermore, instead of adjusting the height of the individual first plane mirrors 105 to the design value, it is only necessary to match the height of the single integrated structure 600 to the design value. The position can be adjusted with high accuracy.

The structure of the monolithic structure 600 is not limited to the above-described structure. For example, variations as shown in FIGS. 6 to 8 are also conceivable, and the structure in these modified examples can achieve the same effects as described above. .
That is, in the configuration of FIGS. 4 and 5, the first flat mirror 105 is formed on a single substrate at intervals along the main scanning direction 211. On the other hand, in FIG. 6, the first plane mirror 105 corresponding to each cell 11, 13,... Arranged in the first column 215 is formed in a continuous region, and similarly each component arranged in the second column 216. The structure which formed the 1st plane mirror 105 corresponding to cell 12, 14, ... in the continuous area | region is shown. Thus, by connecting the mirror portions in the same row, there is an advantage that the mask shape when the first plane mirror 105 is deposited can be simplified.

4 and 5, the first plane mirror 105 and the window portion 601 are formed on a single substrate. On the other hand, as shown in FIG. 7, it is possible to adopt a configuration in which a mirror substrate 605 is fitted in a frame 604. That is, FIG. 8 shows the frame 604 and the mirror substrate 605 separately. As shown in FIG. 8A, the mirror substrate 605 is formed by depositing aluminum on one surface of a glass substrate to form the first flat mirror 105, for example. Here, the mirror substrate 605 formed with the first plane mirror 105 for the cells 11, 13,... Arranged in the first row 215, and the first plane mirror 105 for the cells 12, 14,. The formed mirror substrate 605 is produced. Further, the frame 604 includes a frame frame 607 and a plane portion 606 as shown in FIG. In particular, the flat portion 606 is a thin claw-shaped holding member, and is integrally formed with the frame frame 607 corresponding to a region outside the mirror substrate 605 that does not obstruct the optical path in the mirror substrate 605, and supports the mirror substrate 605. With such a plane portion 606 as a plane reference and the central portion in the sub-scanning direction 212 as a window portion 601, each mirror substrate 605 is attached to the frame frame 607 on both sides thereof. In this configuration, the window portion 601 is a simple space having no members.
By configuring in this way, the installation angle and the installation height of the first plane mirror 105 with respect to all the cells 11, 12, 13,. Thereby, the same effect as the case of the glass substrate integrated structure shown in FIGS. 4 to 7 can be obtained.

  In the configuration of FIG. 7, two mirror substrates 605 each composed of one sheet are used for each of the cells 11, 13,..., 12, 14,. . However, when high reading accuracy is not required in the image reading apparatus, three or more mirror substrates 605 corresponding to each cell 11, 12, 13,... Or formed corresponding to several cells. It is also possible to use. Since these mirror substrates 605 are also arranged using the plane portion 606 as a plane reference, the installation angle and the installation height between the mirror substrates 605 should be aligned with the same accuracy as when using the two mirror substrates 605 described above. Is possible.

Embodiment 2. FIG.
FIG. 23 shows an image reading apparatus 502 according to the second embodiment. This image reading device 502 corresponds to a modification of the image reading device 501 in the above-described first embodiment, and, like the image reading device 501, the integrated structure 600 is formed between the first lens 100 and the aperture 101. While having the structure which provided the formed 1st plane mirror 105, it is further equipped with the following structures. Therefore, in the following, description of the same components as those of the image reading apparatus 501 of the first embodiment will be omitted, and only parts different from the image reading apparatus 501 will be described.

  In addition to the first plane mirror 105, the image reading apparatus 502 further includes a second plane mirror 106 in the optical path between the aperture 101 and the second lens 102, and the optical path is further bent by the second plane mirror 106. Have That is, the reflected light that has passed through the aperture 101 is reflected by the second plane mirror 106, the optical path is bent, and reaches the second lens 102. The light rays reflected by the second lens 102 are respectively applied to the image sensor sections 41, 43,... Corresponding to the cells 11, 13,... And the image sensor sections 42, 44,. Reach.

  The image reading apparatus 502 according to the second embodiment configured as described above has a great advantage that a second apparatus can be manufactured by providing the second plane mirror 106 and bending the optical path.

Embodiment 3 FIG.
FIG. 24 shows an image reading apparatus 503 according to the third embodiment. The image reading device 503 corresponds to a modification of the image reading device 501 in the first embodiment described above, and in the same manner as the image reading device 501, the first plane mirror is provided in the optical path between the first lens 100 and the aperture 101. 105, and further has the following configuration. Therefore, in the following, description of the same components as those of the image reading apparatus 501 of the first embodiment will be omitted, and only parts different from the image reading apparatus 501 will be described.

  In the image reading apparatuses 501 and 502 according to the first and second embodiments described above, the first plane mirror 105 is provided. However, as shown in FIGS. 1 and 23, the reflected scattered light from the document 7 is directly applied to the first lens 100. Is reflected. On the other hand, in the image reading apparatus 503 according to the third embodiment, as shown in FIG. 24, a third plane mirror 107 is installed in the optical path between the document 7 and the first lens 100, and The optical path of reflected light reaching the lens 100 is bent by a third plane mirror 107. Further, the third plane mirror 107 is also integrally formed in the same manner as the first plane mirror 105 described above. Further, the third plane mirror 107 and the first plane mirror 105 are formed on the same integral member 620. The integrated member 620 will be described in detail below.

In the image reading apparatus 503 according to the third embodiment, as shown in FIG. 24, the first plane mirror 105 and the third plane mirror 107 are located at the lower part of the apparatus. Therefore, in the integrated member 620, the reflected light of the document 7 does not pass through the portions sandwiched between the first flat mirrors 105 on both sides like the integrated structure 600 described above. Therefore, in the integral member 620, it is not necessary to integrally configure the plane mirror and the window portion.
On the other hand, the first plane mirror 105 and the third plane mirror 107 are located adjacent to each other. Therefore, as shown in FIG. 25, the integral member 620 is formed by depositing aluminum on one surface of a flat glass substrate 603 to form a mirror portion. This mirror unit corresponds to the first plane mirror 105 and the third plane mirror 107. As shown in FIG. 24, the first plane mirror 105 and the third plane mirror 107 may be separated to form the mirror part. As shown in FIG. 25, the glass substrate 603 is not distinguished from each other. One whole surface may be formed as a mirror part.

  Thus, by comprising the 1st plane mirror 105 and the 3rd plane mirror 107 with the integral member 620, there exists the said 1st and 4th effect among the effects which the integrated structure 600 described in Embodiment 1 show | plays. be able to. That is, the number of parts can be reduced by configuring a plurality of plane mirrors of the first plane mirror 105 and the third plane mirror 107 as an integral member. Further, the installation angles and height positions of the first plane mirror 105 and the third plane mirror 107 in the plurality of plane mirrors can be made uniform.

  The image reading apparatus 503 according to the third embodiment configured as described above has a great advantage that a smaller apparatus can be manufactured by providing the third plane mirror 107 and further bending the optical path.

1 imaging optical system, 2 illumination light source, 3 top plate, 4 substrate, 5 memory,
6 Processing device, 7 Document, 8, 9 Reading line,
11, 12, 13, 14,... Cell, 31, 32, 33, 34,...
41, 42, 43, 44,...
100 first lens, 101 aperture, 102 second lens,
105 first plane mirror, 106 second plane mirror, 107 third plane mirror,
126 light shielding member, 127 partition wall,
202 shielded light beam, 203 dotted line area, 211 main scanning direction,
212 Sub-scanning direction, 215 1st row, 216 2nd row,
501-503 image reading device,
600 monolithic structure, 601 window, 604 frame.

Claims (7)

A light source for illuminating the document;
An imaging optical system that focuses light reflected from the original by the light from the light source and forms an image as an image, and the imaging optical system includes a plurality of cells, each of which is an optically independent optical system. The plurality of cells are arranged along the main scanning direction, arranged in two rows of the first row and the second row in the sub scanning direction perpendicular to the main scanning direction, and the first row and The cells in the second row are arranged in a staggered manner in the main scanning direction, the imaging optical system,
A plurality of image sensor sections that are arranged corresponding to the cells and receive light that has passed through the cells;
A memory for storing image information of the original document sent by the image sensor units corresponding to each other in the sub-scanning direction;
An image reading apparatus comprising: a processing device that synthesizes image information of adjacent cells so as to match images in a region where the image information stored in the memory overlaps;
Each of the cells includes a first reflection-type condensing optical element and a second reflection-type condensing optical element that reflect and collect light from the original, a first plane mirror, and an aperture. the from the document in the cell in the traveling direction of the light toward the image pickup device unit first reflection type light-condensing optical element, the first plane mirror, the aperture in the order of the second reflection type light-condensing optical element Place these,
A monolithic structure provided with a plurality of the first plane mirrors corresponding to the plurality of cells ;
An image reading apparatus. The image reading apparatus according to claim 1, wherein the monolithic structure has all the first plane mirrors corresponding to all the cells. In the cell, the aperture is disposed at a focal position on the back side of the first reflective condensing optical element to form a telecentric optical system on the document side, and in the two rows of the imaging optical system. 3. The image reading apparatus according to claim 1, wherein each of the cells arranged in the first and second cells is arranged such that light rays from the original to the cell are parallel to each other among principal rays. The first plane mirror is arranged in two rows in the sub-scanning direction corresponding to the cells in the first row and the second row, and the document is placed in an area sandwiched between the rows of the first plane mirror. The image reading apparatus according to claim 1, wherein a window portion that allows a light beam incident on each cell to pass therethrough is formed. The image reading apparatus according to claim 4 , wherein the window has an infrared cut filter. Further comprising a frame for mounting said integral structure having the first plane mirror, the image reading apparatus according to any one of claims 1-5. The cell further includes a second plane mirror, and the first reflection type condensing optical element, the first plane mirror, the aperture, and the second in the traveling direction of the light from the document to the image sensor section in the cell. plane mirror, the second and place these in the order of the reflection type light-condensing optical element, an image reading apparatus according to any one of claims 1 to 6.

Images