JPH05153332A - Picture reader - Google Patents

Abstract

PURPOSE:To prevent color slurring of a picture. CONSTITUTION:A light beam including picture information of an object G to be read is led to an optical separation optical element 44 via optical means 20, 30, 42. The light beam is separated spacially for each color component at a prescribed pitch and the image of the light beam corresponding to the color component is formed to a detection section of a CCD sensor 46. The detection sections are arranged at the prescribed pitch and a slit 27 to limit passing of the light beam is provided between the optical means 20 and the object G to be read corresponding to the prescribed pitch.

Description

Detailed Description of the Invention

 [Object of the Invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image reading apparatus for reading a color image for inputting a color image to an image processing apparatus connected to a computer or the like, and particularly to preventing color misregistration in the color image reading apparatus. Regarding improvement of optical system.

[0002]

2. Description of the Related Art Generally, in order to input a color image to an image processing device connected to a computer or the like, a color image reading device for reading a color image is used. In such a color image reading apparatus, an original is placed on a transparent original placing table made of glass or plastic, and image information on the original surface is imaged on a reading device such as a CCD sensor by an imaging lens system. It The image information formed on the CCD sensor is converted into an electric signal by the CCD sensor, stored in a predetermined memory as an image information signal, or output to an image forming apparatus or the like connected to the outside.

In the above-mentioned color image reading apparatus, a 1-line CCD method and a 3-line CCD method have already been proposed as a method for reading a color image. In a color image reading apparatus adopting the 1-line CCD method, an original is read by one CCD line sensor. That is, the same area on the original is scanned three times, and the color separation filter attached to the imaging lens system is changed for each scan to decompose the image information of the area into three color components, and each scan is performed. Image signals corresponding to the three color components are generated as image information from the CCD line sensor. Image signals obtained by these three scans are combined to reproduce a one-line color image. On the other hand, in a color image reading apparatus adopting the 3-line CCD method, the image on the original is read by the three CCD line sensors. That is, areas on different originals corresponding to the arrangement pitch of the CCD line sensors are simultaneously scanned, and image signals from the individual line sensors are generated as different color component image information of different areas. Image signals obtained one by one by this scanning are combined to reproduce a color image on the original.

The 1-line CCD method has a low reading speed because it requires three scans for one document, and is mainly used in a reading device for reading an image at a low speed. Also,
A memory is required for each color component, and image information obtained by scanning three times needs to be combined. At the time of alignment when synthesizing the image information, high precision is required for the drive device of the image reading device and the structure of the device, and its control is also very complicated.

The 3-line CCD method has a high reading speed because the image information can be read by one scanning with respect to one document, and is used in a reading device for reading an image at a relatively high speed. However, in the 3-line CCD sensor used in this method, three 1-line CCD sensors
Since they are formed in one unit, the document reading position is different. Therefore, the image signals of each color component in the same area are output at different timings according to the arrangement pitch of the three line CCD sensors. As a result, the read image information is deviated for each color component. Various methods have been proposed as methods for removing the deviation for each color component in the above-described 3-line CCD sensor method.

Japanese Unexamined Patent Publication No. 1-97056 discloses 3-line C
An example is disclosed in which an image of an area corresponding to the arrangement pitch of the CD sensor is read, image information is stored in a memory for each color component, and a positional deviation between the color components of this image information is electrically corrected. ing. According to this method, the deviation between the color components of the image information due to the arrangement pitch of the CCD sensors is removed. However, similar to the 1-line CCD method described above, there is a problem that complicated image information synthesis is required.

Further, in Japanese Patent Laid-Open No. 2-115816, image information is read by shifting the reading position according to the arrangement pitch of each line CCD sensor, and the image information due to the arrangement pitch of each line CCD sensor is read. A method for optically removing the deviation of each color component is disclosed.

[0008]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the color image reading device disclosed in No. 7056,
With respect to the arrangement pitch of the individual line CCD sensors of the three-line CCD sensor, that is, the deviation of the image information of each color component due to the interval of the line CCD sensors caused by the CCD charge transfer paths arranged on both sides of each line CCD sensor The image information is read by slightly shifting the reading position itself with respect to the interval between the line CCD sensors. The image information read after being slightly shifted is synthesized using a memory, and the deviation of the image information of each color component is removed.

However, the above-mentioned Japanese Patent Laid-Open No. 1-97056.
In the color image reading device disclosed in Japanese Laid-Open Patent Publication No. 2000-242242, when the image to be read is a color image, since the image information also includes gradation data, an interline correction memory having an enormous storage capacity is required. There's a problem. If the image reading device is provided with a zoom function, etc., the number of lines in the line memory must be changed depending on the magnification, and extremely complicated processing such as performing calculations between lines is required, increasing the circuit scale. There is a problem inevitable of high cost. Further, since the reading position itself is slightly shifted, there is a problem that the reading position of each color component is displaced due to mechanical vibration in the sub-scanning direction, resulting in color misregistration and color fringing in the output image. Naturally, if the speed of the read object is not stable,
Alternatively, if the speed is unknown from the beginning, the amount of correction in the line-to-line correction memory cannot be determined, and therefore image reading without color misregistration becomes impossible. Further, in the alignment when synthesizing image information, there is a problem that high accuracy is required for the drive device of the image reading device and the structure of the device, and its control becomes very complicated.

In the color separation device disclosed in the above-mentioned Japanese Patent Laid-Open No. 2-115816, the arrangement pitch of a plurality of line CCD sensors in which light beams corresponding to image information are arranged in parallel on the same plane. The color separation means is used for performing color separation at intervals corresponding to the color separation and setting the color-separated light beam to be transmitted in the same direction, and the deviation of the image information of each color component is optically removed.

However, the above-mentioned JP-A-2-11581
The color separation means disclosed in No. 6 has a light-transmissive member as a substrate, a light beam reflecting surface that reflects a light beam is provided on one surface, and the other surface parallel to the light beam reflecting surface is provided. Is composed of a dichroic prism provided with a color selection surface for selectively transmitting and reflecting the color components contained in the light beam. Therefore, when the array pitch of each line CCD sensor is small, such as when using a three-line CCD sensor, it is necessary to reduce the plate thickness of the dichroic prism. Therefore, when the light beam reflecting surface or the color selecting surface is formed on the translucent member by a method such as vapor deposition, there is a problem that the translucent member warps and the image plane is not stable. Further, when the arrangement pitch of each line CCD sensor is small, such as when using a three-line CCD sensor, it is necessary to form a plurality of color selection surfaces adjacent to each other corresponding to the arrangement pitch of each line CCD sensor. There is a problem in that it is difficult to form the surface, which increases the cost. Furthermore, when a light ray enters the prism or emerges from the dichroic prism, refraction of the light occurs and the optical path is changed, which causes a problem that the image plane shifts.

Further, in the optical system using the color separation means disclosed in Japanese Patent Laid-Open No. 2-115816, the shape of the optical system is changed and redesigned each time the pitch between the CCD sensors used is changed. However, there is a problem that the manufacturing cost becomes high.

Further, the light beam color-separated by the color separation means disclosed in Japanese Patent Laid-Open No. 2-115816 is
Photoelectric conversion is performed by each line CCD sensor. However, since the sensitivity of each line CCD sensor differs depending on the wavelength of the light beam, when the color-separated light beam is photoelectrically converted by each line CCD sensor, the level of each output signal becomes different for each color. Therefore, for example, when performing 256-gradation A / D conversion processing on these output signals, A
When the reference voltage for the A / D conversion is set, the A / D conversion using the 256 gradation full scale cannot be performed for the signal having a relatively low output level, and the gradation is deteriorated. It becomes a problem in processing.

Furthermore, a part of the light beam emitted from the optical path length correction means used in the color separation means disclosed in the above-mentioned JP-A-2-115816 is reflected by the cover glass of each line CCD sensor. , A part of this reflected light is reflected again at the exit surface of the optical path length correction means and each line C
When the light enters the CD sensor, stray light appears in the output image, which causes a problem. Similarly, in the case of the optical system using the color separation means disclosed in Japanese Patent Application Laid-Open No. 2-115816, the dimensional accuracy of the color separation means is adjusted to completely match the pitch between the photoelectric conversion elements of the photoelectric conversion means. There is also a problem that the manufacturing cost must be high because it has to be extremely high.

An object of the present invention is to optically prevent color misregistration of an image due to detection of each color component of image information at different reading positions in a color image reading apparatus using a 3-line CCD method. Another object of the present invention is to provide a color image reading device capable of performing the above.

[0016]

The present invention has been made on the basis of the above problems. According to the present invention, light source means for irradiating an object to be read with a light beam and a light beam from the object to be read are provided. Optical means for transmitting, an optical element for dividing the light flux from this optical means into a plurality of light fluxes separated by a predetermined distance, and a position for receiving each of the light fluxes divided by this optical element, provided via different color filters An image reading apparatus is provided, which comprises a plurality of detection units thus formed and a detection chip formed on a single substrate.

According to a preferred embodiment of the present invention, the optical element reflects the light beam from the object to be read in a first direction and transmits the light beam in a second direction different from the first direction. It comprises a first prism means having a first optical surface, and a flat-plate refracting means for guiding the light beam transmitted by the first prism means in the second direction. A third optical surface that has a second optical surface that guides the reflected light flux in the first direction and that transmits the light flux from the second optical surface in the first direction and reflects in the second direction. The luminous flux reflected by the third optical surface is reflected in the first direction by the second optical surface, and the luminous flux guided from the first, second and third optical surfaces in the first direction is ,
There is provided an image reading device characterized by being guided to different detecting units.

Further, according to a preferred embodiment of the present invention, the filter through which the corresponding luminous fluxes of the plurality of detecting portions pass respectively has a transmittance corresponding to a rate at which the corresponding luminous flux is attenuated in the optical element. An image reading apparatus is provided having the following.

Further, according to a preferred embodiment of the present invention, the optical element includes second prism means having a fourth optical surface, and the first optical surface of the first prism means is a flat plate. The image reading device is characterized in that it is joined to the third optical surface of the flat refracting means, and the second optical surface of the flat refracting means is joined to the fourth optical surface of the second prism means. Provided.

Furthermore, according to a preferred embodiment of the present invention, the flat plate refracting means is interposed between the first and second prism means, and the first prism means and the flat plate refracting means are provided. Also, there is provided an image reading device characterized in that the flat plate-shaped refracting means and the second prism means are adhered by optical contact, respectively.

According to the invention, the light source means for irradiating the object to be read with the light beam, the optical means for transmitting the light beam from the object to be read, and the incident light beam from the optical means are arranged at a predetermined pitch. Are divided into a plurality of light fluxes by an optical element which emits the plurality of light fluxes in substantially the same direction as the incident direction of the incident light flux, and the light fluxes divided by the optical element are arranged at the predetermined pitch. An image reading apparatus is provided, which is provided with a detection chip in which a plurality of detection units are formed on a single substrate.

According to a preferred embodiment of the present invention, the optical element has a reflecting surface for reflecting the incident light beam, and reflects the light beam totally reflected by the total reflection surface in a first direction, First prism means having a first optical surface for transmitting in a second direction different from the first direction, and a plate-like refraction for guiding the light beam transmitted by the first prism means in the second direction. The plate-shaped refracting means has a second prism optical surface that guides the guided light beam in the first direction, and transmits the light beam from the second prism optical surface in the first direction. Having a third optical surface that reflects in the second direction, the light flux reflected by the third optical surface is reflected by the second optical surface in the first direction, and the first, second, and third optical surfaces are reflected. The light beam guided from the optical surface in the first direction is
There is provided an image reading device characterized by being guided to different detecting units. Further, according to a preferred embodiment of the present invention, there is provided an image reading device characterized in that different color filters are respectively provided in the plurality of detection units.

Further, according to a preferred embodiment of the present invention, there is provided an image reading apparatus, wherein the filter has a transmittance corresponding to a rate at which a corresponding light beam is attenuated in the optical element. It

Still further in accordance with a preferred embodiment of the present invention the optical element includes second prism means having a fourth optical surface, the first optical surface of the first prism means comprising: An image reading apparatus characterized in that it is joined to the third optical surface of the flat refracting means, and the second optical surface of the flat refracting means is joined to the fourth optical surface of the second prism means. Will be provided.

According to another preferred embodiment of the present invention,
An image reading apparatus is provided, wherein the first prism means and the plate-shaped refracting means, and the second prism means and the plate-shaped refracting means are adhered by optical contact, respectively.

According to another preferred embodiment of the present invention, light beam limiting means for limiting the light beam width corresponding to the predetermined pitch is provided near the object to be read of the optical means. An image reading device is provided.

Further, according to another preferred embodiment of the present invention, the plate-shaped refracting means decomposes the light beam and reflects the light beam, and the plate-shaped refraction member having a thickness corresponding to the predetermined pitch. There is provided a thin film, which is formed in the central portion of the light beam decomposition surface and the light beam reflection surface.

Furthermore, according to another preferred embodiment of the present invention, there is provided an image reading apparatus in which the optical element is joined by optical contact using a portion where the thin film is not formed.

According to still another preferred embodiment of the present invention, the first prism and the flat refracting member, and the second prism and the flat refracting member are respectively the same as the flat refracting member. There is provided an image reading device characterized by being bonded with an adhesive having a refractive index.

According to still another preferred embodiment of the present invention, the flat refracting means is made of an adhesive having the same refractive index as that of the first prism and the second prism. An image reading device is provided.

According to still another preferred embodiment of the present invention, the ratio of decomposing the light beam is set so as to reduce the difference in output signal level from the detection chip. An image reading device is provided.

According to still another preferred embodiment of the present invention, the image reading apparatus is characterized in that the first and second prism means and the flat refracting member are made of the same material. Will be provided.

According to still another preferred embodiment of the present invention, the light beam decomposing surface is formed of a dielectric multilayer film. The image according to claim 6, Reader. According to still another preferred embodiment of the present invention, the image reading apparatus is characterized in that an antireflection film is provided on a surface of the optical element on which the light beam enters and exits.

Furthermore, according to still another preferred embodiment of the present invention, the one having the lowest sensitivity among the detectors is arranged so as to receive the light beam having the highest light amount decomposed by the optical element. An image reading device characterized by being provided. According to still another preferred embodiment of the present invention, there is provided an image reading device characterized in that the optical element is movably and rotatably supported.

[0035]

According to the present invention, when reading a color image, the image information of a single line obtained by the optical means is
An optical element using a prism disperses and forms an image on a plurality of detectors, that is, image sensors arranged at a predetermined pitch. Therefore, the deviation of each color component caused by the arrangement pitch peculiar to the plurality of arranged detection units does not occur. Further, when the dimensional accuracy of the optical element is low and an image is not correctly formed, the color shift can be prevented by rotating the optical element. There is no change in the optical path due to the difference in the refractive index when the light is decomposed by the optical element, and the light beam can be accurately dispersed and imaged on the plurality of detection units. Even if the reading unit is changed to a plurality of line sensors having different arrangement pitches between the sensors, it is possible to perform reading without deviation without changing the shape of the optical component. Further, the difference in the output signal level due to the difference in sensitivity between the plurality of image sensors and the method of decomposing the light beam is reduced. It is possible to prevent the deterioration of the image due to the reflection of the light beam by the cover glass of the line CCD sensor.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image reading apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an image reading apparatus according to an embodiment of the present invention. As shown in FIG. 1, the image reading device 2 includes a first reflection unit 20 and a first reflection unit 20 which guide a reflected light beam from a document surface into the second reflection unit 30 by reflecting the light beam once inside the image reading device 2. A second reflection unit 30 that reads image information by reflecting the light beam from the inside twice and guides it to the image reading unit 40, and a drive mechanism described later, and these units 20, 30, 40 are stored. Housing 10
Is equipped with.

The housing 10 is provided with a reading window 14 having a flat surface on which an original is placed, and an original pressing member 12 for bringing the original placed on the reading window 14 into close contact with the reading window. Further, the housing 10 is provided with a document holder 12
And a drive mechanism (not shown) for moving the reading window 14 on the first reflection unit 20 in the sub-scanning direction Sa, in which an image for reading the image information from the document surface G of the document is formed. The reading unit 40 and a signal processing unit (not shown) that processes a signal from the image reading unit 40 and outputs the image signal as an image signal are provided. Next, each device or unit shown in FIG. 1 will be described in detail.

The reading window 14 arranged on the upper part of the housing 10 is a transparent plate made of glass, for example, and is arranged substantially horizontally. In this reading window 14,
In order to clearly take out the image information to be read, the document is turned upside down, that is, the document surface G is placed inside the housing 10 and the document surface G of the document is placed in close contact with the flat surface of the reading window 14. It The document retainer 12 and the reading window 14 are moved on the housing 10 along the sub-scanning travel Sa by a drive mechanism (not shown).

The first reflecting unit 20 installed substantially parallel to the reading window 14 illuminates the original surface G of the original that is in close contact with the reading window 14 as shown in FIG. 2, and a light beam from the lamp 24. A concave reflecting plate 26 that focuses the light to efficiently illuminate the document surface, a first mirror 22 for guiding a part of a reflected light beam reflected from the document surface G of the document to the second reflection unit 30, and a document surface G of the document. A slit 27 for narrowing the reflected light from the lamp to a predetermined width, and a light blocking plate 28 for blocking the light source light from the lamp 24 so as not to directly enter the first mirror 22. The lamp 24, the reflection plate 26, the slit 27, the light shielding plate 28, and the first reflection mirror 22 that guides a part of the reflected light from the document surface G to the second reflection unit 30, the document pressing member 12 and the reading window 14 move, respectively. Is extended in the scanning direction orthogonal to the sub-main scanning direction Sa, and the first surface is moved at a predetermined position in the sub-main scanning direction Sa so as to completely scan the document surface.
It is fixed to the reflection unit 20.

As shown in FIG. 1, the second reflecting unit 30 reflects the reflected light from the document surface G of the document twice and guides it to the reading section for reading the image information.
2, 34 are provided. The second and third mirrors 32,
34 is fixed in the second reflection unit 30 so as to extend in the main scanning direction. Here, the second mirror 32
Are arranged parallel to the first reflecting mirror 22, and the third mirror 34 is arranged so as to be orthogonal to the first and second reflecting mirrors 22 and 32.

The image reading unit 40 has the image forming lens unit 42 in which a plurality of lenses are combined with the light beam containing the image information guided from the second reflecting unit 30, and the photolytic function shown in FIG. It is guided to the image reading element shown in FIGS. 4 and 5, that is, the 3-line CCD sensor 46 through the photolytic element 44, converted into an electric signal by the 3-line CCD sensor 46, and subjected to predetermined processing in the signal processing unit. Then, the image data is sent to an external image forming apparatus, a storage device, or the like (not shown).

As shown in FIG. 4, the 3-line CCD sensor 4
6 has three line CCD sensors 46r, 46g, 46b extending in the main scanning direction, and as shown in FIG. 5 in which the area A shown in FIG. 4 is enlarged, the line CCD sensor 46 is provided.
r, 46g, 46b are the same number of pixels 47r, 47g, 4
7b, each corresponding pixel 47r, 47
g and 47b are aligned and arranged in the sub-scanning direction. This line CCD 46b, 46g, 46
As shown in FIG. 5, r is formed so that the size of one pixel is 14 μm square. Therefore, for example, when a document is read at a resolution of 4 lines / mm, the size of the read pixels on the document surface G is 250 μm square, so the magnification of the imaging lens 42 shown in FIG. 1 is 1 / 17.86. Is set to.

In the 3-line CCD sensor 46, C is provided on the side of each line CCD sensor 46r, 46g, 46b.
A CD charge transfer path is provided, which allows a line CCD
The sensors 46r, 46g, 46b are arranged with a predetermined space. This arrangement interval, that is, its pitch p is unique to the 3-line CCD sensor, and is set to about 168 μm in this embodiment.

On the light incident surface of the line CCD sensor 46r, a red filter L1 having a spectral characteristic FR shown in FIG.
The light incident surface of the CD sensor 46g is provided with the green filter L2 having the spectral characteristic FG shown in FIG. 6, that is, the characteristic of transmitting green light, and the light incident surface of the line CCD sensor 46b is shown in FIG. A blue filter L3 having a spectral characteristic FB, that is, a characteristic of transmitting blue light is provided. This 3-line CCD 46 is further provided with each line CC
A cover glass 48 for protecting the detection surface of D is provided on the front surface of the detection surface.

Further, in the above-mentioned embodiment, in order to prevent ghosts from being produced in the reproduced image, the intervals between the line CCD sensors 46r, 46g and 46b, that is, the pitch p.
The width w of the slit 27 provided in the first reflection unit 20 corresponding to the above, to be more precise, the one-line reading width of the original image is set by the magnification a of the imaging lens 42 and the arrangement pitch p of the line CCD sensors, The width s of the light detection surface of each CCD sensor, the width w of the slit 27, and the pitch p are determined so as to satisfy the following relationships. w <(2p-s) · a
From this relational expression, in the embodiment of the present invention, the width w of the slit is
Is set to 3 mm.

The reason why the slit 27 is provided will be described. The light beam L reflected from the document surface G by using the above-described photolytic element 44 is supplied to the line CCD sensor 46b,
When disassembling corresponding to the arrangement pitch p of 46g and 46r,
If the slit 27 is not arranged in the first reflecting unit 20 described above, the following problems occur due to the structure of the photolytic element 44. That is, when the document surface G1 of a document having areas P1 to P7 as shown in FIG. 7 is read, if the slit 27 is not provided in the first reflection unit 20,
As shown in FIG. 8, each line CCD sensor 46b,
In 46g and 46r, primary reflected light L1 and secondary reflected light L having image information segments of areas P1 to P7, respectively.
2nd and 3rd reflected light L3 are directed at the same time, line CCD
On each of the sensors 46b, 46g, 46r, three adjacent image information segments of the areas P1 to P7 are simultaneously imaged, and a kind of ghost phenomenon occurs. But,
The slit 2 having a predetermined width w in the first reflection unit 20.
In the case where No. 7 is provided, as shown in FIG. 9, even if the reflected lights L1, L2 and L3 are read at the same time, the slits 27 shield the areas P1 to P7 other than the image segment P4 and the areas P1 to P7. Only the image segment P4 of P7 is the line CCD sensor 46b, 46g, 46r.
Is incident on each of. The optical signal that causes the above-mentioned ghost phenomenon is not imaged on the line CCD sensor, and therefore the ghost phenomenon does not occur. Next, the process in which the image information on the document surface G of the document is guided to the image reading unit will be described in detail.

The illumination light beam Lw from the lamp 24 disposed in the first reflection unit 20 is guided to the original surface G of the original directly or after being reflected by the reflection plate 26, and efficiently illuminates the original surface G. .. The document surface G has the condensed illumination light beam Lw.
It is illuminated by and emits reflected rays in unspecified directions. A part of the reflected light beam L from the document surface G passes through the slit 27 as shown in FIG.
First, the first fixed unit is fixed to the first reflection unit 20.
The light is reflected by the mirror 22 in the sub-scanning direction Sa and is incident on the second mirror 32 fixed to the second reflection unit 30. Here, the light shield plate 28 causes the light rays other than the reflected light ray L from the document surface G of the document to directly and indirectly.
It is prevented to be led to 2.

The light ray L incident on the second mirror 32 is reflected at a right angle toward a third mirror 34 arranged so as to be orthogonal to the second mirror 32, and is incident on the third mirror 34. The light ray L incident on the third mirror 34 is reflected at a right angle again, is directed in the substantially sub-scanning direction Sa, and is guided to the image reading unit 40. That is, the reflected light ray L including the image information from the document surface G is guided to the image reading unit 40 by being bent twice by 180 degrees by the second reflection unit 30.

Light ray L guided to the image reading unit 40
Are focused by the lens unit 42. As shown in FIG. 3, this converging light beam is decomposed into color components of image information, that is, blue, green, and red components Lb, Lg, and Lr by the photolytic element 44, and at the same time, in the photolytic element 44. It is reflected at different positions and its direction is approximately 9
It is folded back at 0 ° and guided to the image reading element, that is, the 3-line CCD sensor 46. Decomposed reflected rays Lb, Lg,
Lr is an image reading element, that is, the 3-line CCD sensor 4
The image is formed on each of the line CCD sensors 46r, 46g, and 46b equipped with color separation filters of 6 and converted into an electric signal.

The photolytic element 44 shown in FIG. 3 comprises first and second right-angled prisms 44h and 44m each having a right-angled isosceles triangular cross section, and a plate-shaped refraction member 45 provided therebetween. Has been done. Flat refraction member 4
5 has a thickness t corresponding to the arrangement pitch of the line CCD sensors, and the long side surface of the first rectangular prism 44h has
A half mirror surface is formed as a photolytic surface that transmits and reflects light rays by a method such as vapor deposition, and an antireflection film, that is, an AR coat film is provided on the other two short sides. The long-side surface of the second right-angle prism 44m facing the long-side surface of the first right-angle prism 44h has a total reflection surface that reflects light rays,
That is, the mirror surface is formed by a method such as vapor deposition.
The first right-angle prism 44h, the second right-angle prism 44m, and the plate-shaped refraction member 45 are joined to each other by optical contact or an adhesive.

The light ray L guided to the photolytic element 44 is
First, a part of the light rays, that is, the primary reflected light Lb is reflected by the half mirror surface, and the remaining light rays that have passed through the half mirror surface are reflected by the total reflection surface, and a part of the light rays, that is, the second light rays, are reflected by the half mirror surface. The next reflected light Lg is transmitted. The rest of the light reflected by the half mirror surface is reflected by the total reflection surface, and a part of the light rays, that is, the tertiary reflected light Lr is transmitted by the half mirror surface. In this way, the reflected light Lb, L
g and Lr are decomposed at equal intervals.

The light beam thus decomposed is emitted from the photolytic device 44 and guided to the 3-line CCD sensor 46. And the cover glass 48 of the 3-line CCD sensor
A part of the light is reflected by the photo-resolving element 44, and the reflected light is again incident on the photo-decomposing element 44. Since the incident surface at this time is the AR coated surface, the light is reflected here and the third line C again.
It is prevented from being guided to the CD sensor 46. That is, deterioration of an image is prevented by reflection of light rays from the cover glass 48 of the 3-line CCD sensor 46.

Each reflected light ray Lb, Lg, Lr is decomposed.
The spacing is a flat refraction member forming the photolytic element 44.
It is defined by the thickness t of 45. In this example, 3
Each reflected light beam Lb, Lg, Lr of the line CCD sensor 46
Line CCD sensors 46b, 46g, 46r corresponding to
The array pitch p of is unique to the CCD sensor (immediately
The pitch p is constant and cannot be changed. ) Is
Therefore, the thickness t of the plate-shaped refraction member 45 is equal to the arrangement pitch.
It is formed to have a thickness corresponding to p. Half turn back ray L
The mirror surface and the total reflection surface reflect the reflected light ray L at a right angle.
Therefore, they are arranged at an angle of 45 ° with respect to the optical axis. Servant
Thus, the thickness t of the flat plate-shaped refraction member 45 is t = p / 2^1/2  Stipulated in.

First right-angle prism 44 of photolytic element 44
The h and the flat refraction member 45 are preferably made of the same material. If the materials of the first right-angle prism 44h and the plate-shaped refraction member 45 are different, there is the following undesirable problem. That is, in FIG. 10 showing how light rays are decomposed by the photolytic element 44, if the refractive indexes of the first rectangular prism 44h and the flat refracting member 45 are different, the photolytic element 44 is indicated by the solid line. Refraction occurs in the reflected light beam L from the document G traveling in the inside, and the desired light path shown by the broken line in FIG. 10 does not travel. However, if the first right-angle prism 44h and the plate-shaped refraction member 45 are made of the same material, such refraction of light rays can be prevented. Therefore, as shown by the broken line in FIG.
The light rays are decomposed according to the arrangement pitch of the CD sensors, and the reflected light rays L are reflected on the line CCD sensors 46r, 46g, 46b.
b, Lb, and Lr are surely directed.

The half mirror surface of the photolytic element 44 is preferably formed of a dielectric multilayer film. This is based on the following reasons. Generally, when a half mirror surface is formed of a metal film, when light enters the half mirror surface, light absorption occurs on this surface. This absorption depends on the film thickness and the type of film, but if this half mirror is made of a chrome film or an aluminum film, the total incident light is 3
0 to 40% is not transmitted or reflected and is absorbed by the film. As a result, the amount of light guided to the 3-line CCD sensor 46 is greatly reduced. In order to prevent this decrease in light amount, it is necessary to take measures such as increasing the light amount of the lamp that illuminates the original, but the power consumption of the device increases,
There is also a method of increasing the amplification degree of the output signal of the sensor to an apparent image signal level, but a decrease in the S / N ratio is unavoidable, resulting in a problem that the image quality is deteriorated. On the other hand, when the half mirror surface is formed by the dielectric multilayer film, the dielectric material as the material of the film hardly absorbs light, and thus the above-mentioned measures are unnecessary. From this, the half mirror surface is preferably formed of a dielectric multilayer film.

As shown in FIGS. 11 and 12, the plate-shaped refraction member 45 is attached to the prisms 44h and 44m with the adhesive 45.
When they are joined by a and 45b, the accuracy of the thickness of the flat refraction member 45 can be satisfied by adjusting the thickness of the adhesive. The reason for this will be described with reference to FIGS. 11 and 12. In FIG. 11, a broken line indicates reflected light rays Lb, Lg, and Lr from the mirror surface when the plate-shaped refracting member 45 has a uniform thickness and is formed on an ideal mirror surface as indicated by a dashed line. Shows reflected light rays Lb, Lg, and Lr from the mirror surface when the flat refracting member 45 is formed on the mirror surface having an uneven thickness. As shown in FIG. 11, when the half mirror surface and the mirror surface are not parallel, the reflected lights Lb, Lg, Lr are not imaged on the CCD sensors 46g and 46r. Usually, as the distance between the photolytic surface, that is, the half mirror surface and the sensor 46 increases, the thickness of the plate-shaped refracting member 45 is required to have high accuracy. Therefore, the first prism 4
4h and the plate-shaped refraction member 45, and the second prism 44m and the plate-shaped refraction member 45 are adhered to each other by using adhesives 45a and 45b having the same refractive index as that of the plate-shaped refraction member 45. Adjusting the plate-shaped refraction member 45
It is possible to satisfy the accuracy regarding the thickness of the. By adjusting the thickness of the adhesive, it is possible to secure the parallelism between the half mirror surface and the mirror surface as shown in FIG. 12, and it is possible to read an image without deviation. However, in order to enable such adjustment, the thickness of the flat plate-shaped refracting member 45 needs to be thinner than the thickness t determined by the arrangement pitch of the sensors by a value corresponding to the thickness of the adhesive. is there.

The plate-shaped refracting member 45 is made of an adhesive, for example, an ultraviolet curable adhesive, and by adjusting the compounding ratio of a plurality of resins, the same refractive index as that of the prism (nD = 1.475 in the case of quartz glass). ) May be given. This is because even if the arrangement pitch p of the 3-line CCD sensor is changed for each device, it is not necessary to change the specifications of other optical parts only by changing the thickness t of the adhesive agent, and in terms of manufacturing and cost. This is because it is very advantageous. Further, when the array pitch p of the sensors is narrow, the plate-shaped refraction member 45 becomes very thin. However, when glass is used for the plate-shaped refraction member 45,
Because of the thinness, the plate-shaped refracting member 45 is warped or the thickness becomes nonuniform, so that the reflected lights Lb, Lg, and Lr may not be correctly imaged on the sensor surface. However, when the plate-shaped refracting member 45 is made of an adhesive, the parallelism of the adhering surface of the prism is maintained, and a shift that may occur in image information is prevented.

The prisms 44h and 44m and the plate-shaped refraction member 45 may be joined by an optical contact method without using an adhesive material. The problem and accuracy of using the adhesive will be further discussed with reference to FIG. FIG. 13 is an enlarged view of the light beam splitting surface of the optical element 44 shown in FIG. In FIG. 13, the first prism 44h, the flat plate-shaped refraction member 45, and the second prism 44m.
And the plate-shaped refraction member 45 are respectively
It shows a state of being bonded by the adhesives 45a and 45b having the same refractive index. Here, when the thickness of the adhesive 45a becomes nonuniform as shown in FIG. 13 and its mirror surface is tilted, the half mirror surface and the mirror surface are not parallel to each other, and the reflected light ray Lg from the document surface G is lost. , Lr are not imaged on the CCD sensors 46g and 46r.
Further, as the distance between the photolytic surface and the sensor 46 becomes longer, the thickness of the adhesives 45a and 45b is required to have higher accuracy. Therefore, the first prism 44h and the flat refracting member 45, and the second prism 44m and the flat refracting member 4
The first prism 44h and the flat refracting member 45, and the second prism 44m and the flat refracting member 45 are formed by using an optical contact method in which the respective adhering surfaces are in a vacuum state without using an adhesive agent for adhering No. 5 to each other. Can be completely adhered. Due to this optical contact, the parallelism between the half mirror surface and the mirror surface depends only on the accuracy of the thickness of the flat refracting member 45, and a more accurate photolytic surface can be obtained.

The half mirror surface and the mirror surface are formed only in the central portion of the long side surface of the prism 44h and the central portion of the long side surface of the prism 44m.
The peripheral part of the prism in which the half mirror surface of h is not formed is brought into contact with one surface of the flat plate-shaped refracting member 45 in a vacuum state so that both are joined by the optical contact method, and the half mirror surface is parallel to the half mirror surface. The mirror surface of the second rectangular prism 44m may be attached to the other surface by optical contact or an adhesive using the peripheral portion of the prism. This is based on the following reasons. If the half mirror surface or the mirror surface is formed on the entire surface of the prism, the following problems occur. That is, when the photolytic element 44 is bonded by optical contact, the bonding surface does not become a vacuum state depending on the type of the half mirror surface or the multilayer film forming the mirror surface, and optical contact cannot be performed. Further, when the photolytic element 44 is bonded with an adhesive, an error occurs in the photolytic pitch due to the thickness of the adhesive, and the nonuniformity of this thickness deteriorates the accuracy of parallelism between the half mirror surface and the mirror surface. Therefore, the decomposed rays Lb, Lg, and Lr are generated by the CCD sensor 46 of each line.
The positions of images on b, 46g, and 46r are displaced.
However, if the half mirror surface and the mirror surface are formed in the central part of the prism, optical contact using the peripheral part of the prism becomes possible. Further, when the photolytic element 44 is bonded with an adhesive, the adhesive can be attached to the peripheral portion of the prism to bond the prism. Therefore, by forming the thickness of the adhesive to be the same as the thickness of the multilayer film as the mirror surface, the thickness of the adhesive does not affect the photodecomposition pitch. The photolytic element 44 is capable of decomposing light rays from the document at a predetermined pitch.

Generally, line CCD sensors 46r, 46
The detection sensitivities of g and 46b have wavelength dependence, and the detection signal levels generated from the respective g and 46b are different even when light rays having the same light intensity level are incident. When the line CCD sensor 46b that detects a blue light ray has the lowest sensitivity and the line CCD sensor 46r that detects a red light ray has the highest sensitivity, the reflected light from the half mirror having the largest light amount among the decomposed light rays. The line CCD sensor 46b is arranged so as to be able to receive Lb, and the line CCD sensor 46r is arranged so as to be able to receive the reflected light beam Lr from the half mirror having the smallest light amount among the decomposed light beams. Further, in such a case, if necessary, the output signal level of the line CCD sensor 46b can be raised, and as a result, the S / N ratio of the image data can be improved. On the contrary, if the line CCD sensor 46r has the lowest sensitivity, the CCD sensor 46r
By arranging in the order of r, 46g, 46b, C
The output signal level of the CD sensor 46r can be increased. That is, in the above optical system, the photolytic element 44
When the transmission and reflection ratios of the half mirror surface are equal (transmittance 50%, reflectivity 50%, loss 0%), the light intensity as the light beam is reflected and transmitted in the optical element 44 is the light beams Lb and Lg. , Lr in that order. Therefore, when the line CCD sensors 46r, 46g, and 46b have characteristics that the detection sensitivity becomes higher in the order of blue, green, and red rays, the line CCDs are in that order.
Sensors 46r, 46g, 46b are arranged, and corresponding light rays Lb, Lg, Lr are line CCDs as shown in FIG.
By making the light incident on the sensors 46r, 46g, and 46b, the difference in detection sensitivity is corrected to some extent.

Further, the line CCD sensors 46r, 46
It is preferable that the filters provided on the light incident surfaces of g and 46b have a light transmission characteristic that corrects this sensitivity characteristic. By adjusting the transmittance of the blue, green and red filters, the line CCD sensors 46r, 46g,
The output signal level from 46b can be approximated to the color components of the original image, and the reproducibility of the original image can be improved.

Further, the light quantities of the decomposed light rays Lb, Lg, and Lr are set to different values depending on the transmittance of the half mirror surface, as is clear from the decomposition process. When a xenon lamp that passes an infrared cut filter is used as the lamp 24 that illuminates the document surface G, the sensitivities of the line CCD sensors 46b, 46g, and 46r are approximately 7.2, 8.5, and 8.8 [V], respectively. / lx ・ sec] is obtained experimentally. In consideration of these sensitivities and the light amounts of the decomposed rays Lb, Lg, Lr, the respective line CCD sensors 46b, 46
The transmittance of the half mirror surface is set so that the difference between the output signal levels of g and 46r is minimized. In this example, assuming that the amount of light incident on the photolytic element 44 is 10 [lx] and the integration time of the 3-line CCD sensor 46 is 10 [msec], the output signal levels of the respective line CCD sensors 46b, 46g, 46r are It is almost as shown in Table 1. Therefore, in the present embodiment, this transmittance is set to approximately 59% according to Table 1. Even when the sensitivity of the lamp or the line CCD sensor that irradiates the document surface G is different from that in the above-described example, the optimum transmittance can be obtained as in the above-described example.

[0064]

[Table 1]

The image reading apparatus of the present invention may detect the light beam directed by the image reading unit 40 in the sub-scanning direction Sa as shown in FIG. In such an image reading apparatus, the photolytic element 44 as shown in FIG.
Is built in. The photolytic element 44 is a first prism 44h provided with a photolytic surface that transmits and reflects light, that is, a half mirror surface 44a provided by a method such as vapor deposition, on one surface having a prism whose cross-sectional shape is a parallelogram. A prism having a cross-sectional shape of an isosceles right triangle, that is, a second prism 44 provided with a light reflecting surface for reflecting light, that is, a mirror surface 44c on a long side of the right prism by vapor deposition or the like.
m and a flat plate-shaped refracting member 45 formed to have a thickness corresponding to the arrangement pitch of the line CCD sensors, and the half mirror surface 44a of the first prism 44h is attached to one surface of the flat plate-shaped refracting member 45. , This half mirror surface 44
On the other surface parallel to a, the mirror surface 4 of the second prism 44m
4c is attached and formed. The white light guided to the photolytic element 44, that is, the light ray L reflected from the document surface G, is
First, the total reflection is performed by the total reflection surface 44b parallel to the half mirror surface 44a of the first prism 44h, and the half mirror surface 4
It is incident on 4a. Next, a part of the light rays, that is, the primary reflected light ray Lb is reflected by the half mirror surface 44a. Next, the remaining light rays that have passed through the half mirror surface 44a are reflected by the mirror surface 44c of the second prism 44m, and some of the light rays, that is, the secondary reflected light rays Lg, are transmitted by the half mirror surface 44a. The remaining light rays reflected by the half mirror surface 44a are all mirror surface 44c of the second prism 44m.
And a part of the light rays are reflected by the half mirror surface 44a.
That is, the tertiary reflected light ray Lr is transmitted. In this way, the reflected light rays Lb, Lg, Lr are separated at equal intervals.

Thus, in the reader incorporating the photolytic element 44 shown in FIG. 15, unlike the reader incorporating the photolytic element 44 shown in FIG. 3, the converging light beam is bent by approximately 90 °. It is directed to the half mirror surface 44a of the first rectangular prism 44h. By thus bending the converging light beam by about 90 °, the light beam is detected by the image reading unit 40 arranged in the sub-scanning direction as shown in FIG. In the optical system shown in FIG. 14, the height of the device can be reduced. still,
In this embodiment, the first prism 4 that returns the light ray L
The half mirror surface 44a of 4h and the mirror surface 44c of the second prism 44m are the total reflection surface 44 of the first prism 44h.
Since the reflected light L from b is reflected at a right angle, it is arranged at an angle of 45 ° with respect to the optical axis o.

In the reading device according to the above-mentioned embodiment, it is preferable that the optical element 44 is rotatably supported. FIG. 16 is an enlarged view of the photolytic surface of FIG. 3, and shows a case where the accuracy of the thickness of the flat plate-shaped refracting member 45 is insufficient, as in FIGS. 11 and 13. In this case, looking at the optical path of the reflected light beam L from the document surface G, the distance between the half mirror surface and the mirror surface is shorter than the pitch p of the line CCD sensor, so that the reflected light Lg and Lr are reflected on the CCD sensors 46g and 46r. The problem that the image is not formed occurs. (A dashed line in FIG. 16 shows an ideal mirror surface, and a broken line shows ideal loci of rays Lg and Lr.)

As shown in FIG. 17, when the optical element 44 is rotated and moved so that the reflected light L from the original enters the flat refracting member 45 at an angle of 45 ° or more (an angle from the normal line). The reflected rays Lb, Lg, Lr are CCs corresponding to
Aimed at the D line sensors 46b, 46g, 46r. In this way, the optical element 44 is the imaging lens 4 shown in FIG.
The two- and three-line CCD sensor 46 is rotatably and movably supported, and the optical element is fixed at an appropriate position to correct an error caused by the thickness of the flat plate-shaped refracting member 45, and the reflected light Lb. , Lg, Lr are accurately imaged on the CCD sensors 46b, 46g, 46r. Similarly, when the distance between the half mirror surface and the mirror surface is longer than the pitch p, the reflected light L from the document is the flat refracting member 45.
To the optical element 4 so that the light is incident at an angle of 45 ° or less.
By rotating and moving 4, the image can be read without color misregistration.

As described above, in the image reading apparatus for reading the image of the original, in the reading direction of one line (that is, the main scanning direction, for example, the short side direction of the original), the reflected light beam L from the original surface G is the CCD sensor. One line is imaged on 46 and is accurately read without generating a ghost, and in the plural line taking-in direction (that is, the sub-scanning direction, for example, the longitudinal direction of the original), the original pressing member 12 and the reading window 14 are at a predetermined speed. First
By moving on the reflection unit 20 in the sub-scanning direction, a plurality of lines are accurately scanned and, for example, all the image information on a document of size A4, B5, etc. is read.

In the above-described embodiments, the case where the light beam reflected from the original is detected has been described. However, the present invention can be applied to an apparatus which is provided with a light source on the original and can read the light transmitted through the original. It's clear. Further, in the above-described embodiment, the example of the line CCD sensor is described as the detector for detecting the light beam, but the detector of the image reading apparatus of the present invention is not limited to the line CCD sensor, and other Obviously, a detector of 1 may be used. Further, in the above-described embodiment, the detector provided with three detection units for detecting the light beam divided into three is described, but the number of detection units is not limited to three, and two or more It is obvious that two or more light beams are separated and two or more detection units for detecting these light beams may be provided in the detector.

[0071]

As described above, according to the present invention,
Unique to multiple line image sensors, because the image information of a single line in the main scanning direction is decomposed by optical elements at intervals corresponding to the array pitch of the line image sensor equipped with a color separation filter. The deviation of each color component due to the arrangement pitch of can be removed. Therefore, a storage unit for storing information from a plurality of line image sensors arranged, a mechanism for correcting the deviation of each color component, or a control device therefor is unnecessary. Further, since the half mirror surface and the total reflection surface for performing the spectroscopy are formed on the rectangular prism having a relatively large volume, it is possible to easily manufacture the optical element.

By closely contacting optical components such as a prism and a light-transmitting material that form an optical element by optical contact, a highly accurate photolytic surface can be obtained, so that a high-quality output image without color shift can be obtained. In particular, a half mirror surface and a multilayer film forming the mirror surface are provided in the central portion of the prism,
When the optical element is bonded using the part where the multilayer film is not formed, the multilayer film is peeled off by optical contact, or the accuracy of the parallelism between the half mirror surface and the mirror surface is poor due to the thickness of the adhesive. It never happens.

When an adhesive having the same refractive index is used to bond the prism and the second prism, it is possible to read an image without deviation even if the dimensional accuracy of the second prism is poor. Further, the ghost phenomenon due to the structure of the optical element can be removed by using a predetermined slit.

Further, by making the materials of the members constituting the photolytic element the same, there is no change in the optical path due to refraction of light, so that a color image without color shift can be obtained. Further, since stray light or the like due to the reflection of the light beam by the cover glass of the line CCD sensor does not occur, it is possible to obtain a high-quality output image without image deterioration.

Further, by making the incident light to the optical element and the emitted light from the optical element in the same direction, the lens for focusing the image information from the original, the optical element, and the line image sensor are the same. Since they can be arranged in a straight line, the substrate that drives the line image sensor or the optical adjustment mechanism of this substrate does not spatially interfere with the light beam or the optical system. Therefore,
Since it is possible to shorten the spatial distance between the optical element and the line image sensor in order to reduce the deviation of the image forming position on the line image sensor, it becomes easy to manufacture the optical element in terms of angular accuracy, Furthermore, the shapes of the optical element and the lens can be made compact. Furthermore, since the light beam and the image forming plane are perpendicular to each other in the current image reading apparatus, it becomes easy to replace this optical system with the optical system of the current image reading apparatus. Further, even if the reading unit is changed to a plurality of line sensors having different arrangement pitches between the sensors, it is possible to perform reading without deviation without changing the shape of the optical component.

When the half mirror surface is formed of a dielectric multilayer film, light is hardly absorbed on this surface, and it is necessary to increase the light amount of a lamp that illuminates the original and to amplify the output signal of the sensor. Disappear. These results,
The structure of the device is simplified and the cost can be reduced.

Further, by arranging the line CCD sensor having the lowest sensitivity among the line CCD sensors so as to receive the light beam having the highest light amount decomposed by the photolytic element,
It is possible to supplement the sensitivity of the line CCD sensor having low sensitivity.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a color image reading device according to an embodiment of the present invention.

FIG. 2 is a sectional view of a first reflection unit used in the image reading apparatus according to the embodiment of the present invention shown in FIG.

FIG. 3 is a cross-sectional view of a photolytic element used in the image reading apparatus according to the embodiment of the present invention shown in FIG.

FIG. 4 is a schematic plan view of the 3-line CCD shown in FIG.

5 is a partially enlarged plan view of the 3-line CCD shown in FIG.

6 is a line CCD of the 3-line CCD shown in FIG.
Spectral characteristics of color separation filters used in sensors

FIG. 7 is a plan view showing an area on a document.

8 is a side view of the reading unit showing the relationship between the line CCD sensor and the image information of the area on the document shown in FIG. 7 in which an image is formed on the reading unit when a slit is not provided.

FIG. 9 is image information of a region on the document shown in FIG. 7 and a line C which is imaged on the reading unit when a slit is provided.
Side view of the reading unit showing the relationship with the CD sensor

FIG. 10 is an explanatory diagram showing ray trajectories when the refractive indices of the first rectangular prism and the second prism are different.

FIG. 11 is an explanatory diagram showing a locus of rays reflected from the mirror surface when the thickness of the second prism is formed to be uniform and non-uniform.

FIG. 12 is an explanatory diagram showing that the parallelism between the half mirror surface and the mirror surface can be ensured by adjusting the thickness of the adhesive.

FIG. 13 is a cross-sectional view schematically showing a structure in which a first prism, a translucent member, and a second prism are bonded together with an adhesive having the same refractive index as the second prism.

FIG. 14 is a sectional view schematically showing an image reading apparatus according to another embodiment of the present invention.

15 is a sectional view of a photolytic element used in the image reading apparatus according to another embodiment of the present invention shown in FIG.

16 is an enlarged schematic cross-sectional view of a photolytic surface of the photolytic element shown in FIG.

17 is an explanatory view showing the photolytic element rotatably supported in FIG.

[Explanation of symbols]

 2 ... Image reading device, 10 ... Housing, 14 ... Reading window, 20 ... First reflection unit, 22 ... First mirror, 24 ... Lamp, 26 ... Reflector, 27 ... Shading plate, 28 ... Slit, 30 ... Second Reflection unit, 32 ... Second mirror, 34 ... Third mirror, 40 ... Image reading unit, 42 ... Imaging lens, 44 ... Photolytic element, 46 ... 3-line CCD sensor

Claims (7)

[Claims] 1. Light source means for irradiating an object to be read with a light beam, optical means for transmitting a light beam from the object to be read, and a light beam from the optical means is divided into a plurality of light rays separated by a predetermined distance. And a detection chip in which a plurality of detection units provided via different color filters are formed on a single substrate at a position for receiving each of the light fluxes divided by the optical element. An image reading device characterized by the following. 2. The optical element has a first optical surface that reflects a light beam from the object to be read in a first direction and transmits the light beam in a second direction different from the first direction. The first prism means is flat plate-shaped refracting means for guiding the light flux transmitted by the first prism means in the second direction, and the guided light flux is guided in the first direction. A flat plate-shaped refracting means having a second optical surface and having a third optical surface which transmits a light beam from the second optical surface in the first direction and reflects it in the second direction; and a fourth optical surface And a second optical means of the first prism means, a first optical surface of the first prism means is joined to a third optical surface of the flat refracting means, and a second optical surface of the flat refracting means is formed.
Is joined to the fourth optical surface of the second prism means, and the light flux reflected by the third optical surface of the flat refracting means is reflected by the second optical surface in the first direction. , The light flux guided in the first direction from the first, second and third optical surfaces,
The image reading apparatus according to claim 1, wherein the image reading apparatus is guided to different detecting units. 3. Light source means for irradiating an object to be read with a light beam, optical means for transmitting a light beam from the object to be read, and an incident light beam from this optical means is divided into a plurality of light beams at a predetermined pitch. Then, an optical element that emits the plurality of light beams in substantially the same direction as the incident direction of the incident light beam, and a plurality of detection units arranged at the predetermined pitch that receive each of the light beams divided by the optical element are provided as a single unit. An image reading apparatus, comprising: a detection chip formed on one substrate. 4. The optical element has a reflecting surface for reflecting the incident light flux, and the light flux totally reflected by the total reflection surface is first reflected.
The second direction different from the first direction while reflecting in the direction of
A first prism means having a first optical surface for transmitting in the direction of, and a flat plate-shaped refracting means for guiding the light beam transmitted by the first prism means in the second direction. Which has a second optical surface that guides light in the first direction and which has a third optical surface that transmits a light beam from the second optical surface in the first direction and reflects the light beam in the second direction And a second prism means having a fourth optical surface, wherein the first optical surface of the first prism means is joined to the third optical surface of the flat refracting means. , Second of plate-shaped refraction means
The optical surface of is joined to the fourth optical surface of the second prism means, and the light flux reflected by the third optical surface of the flat refracting means is reflected by the second optical surface in the first direction, 4. The image reading device according to claim 3, wherein the light beams guided from the first, second and third optical surfaces in the first direction are guided to different detecting portions. 5. The image reading apparatus according to claim 4, wherein the filter has a transmittance corresponding to a rate at which a corresponding light beam is attenuated in the optical element. 6. The light beam limiting means for limiting the light beam width corresponding to the predetermined pitch is provided near the object to be read of the optical means. The image reading device described in the item. 7. The first prism means and the flat refracting means, and the second prism means and the flat refracting means,
The image reading device according to claim 4, wherein the image reading device and the plate-shaped refraction unit are adhered by an adhesive having the same refractive index.