JP2009141733A - Image reading apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image reading apparatus suppressing color slippage from being generated in a read image, the image reading apparatus being configured to read a color image by sequential irradiation with light in a plurality of colors. <P>SOLUTION: A slider 16 moves in a prescribed direction along with a surface of a document P. Light sources 20R, 20G, 20B are mounted in the slider 16 and sequentially irradiate the document P with light in different colors, respectively, while the slider 16 moves. When the slider 16 is located in a photographing position RL, GL, BL, a light receiving device 26 photographs an image of the document P with light reflected on the document P. When the slider 16 is located in the photographing position RL, an optical axis is moved to an upstream side of an x-axis direction by a fluid lens 28, and when the slider 16 is located in the photographing position BL, the optical path is moved to a downstream side of the x-axis direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an image reading apparatus, and more particularly to an image reading apparatus including a plurality of light sources that emit light of different colors.

  In an image reading apparatus, there are two types of methods for reading a color image: a color filter method and a light source switching method. In the color filter method, a plurality of filters that transmit light of R (red), G (green), and B (blue) are provided on the photographing element, the white light is irradiated to the original, and the image is reflected by the reflected light from the original. It is a method to shoot. On the other hand, in the light source switching method, a light source that emits red light, a light source that emits green light, and a light source that emits blue light are provided, and red, green, and blue light are sequentially applied to the document by each light source. This is a method in which an image is photographed by irradiation and reflected light from the original. The light source switching method is generally applied to a low-cost CIS (contact image sensor) type image reading apparatus.

  Here, the light source switching method has a problem that color misregistration occurs in a read image, as will be described below with reference to the drawings. FIG. 9 is an explanatory diagram for explaining that color misregistration occurs in an image read by the light source switching method. FIG. 9 shows a document P and a slider 101. Hereinafter, a direction in which the slider 101 moves is referred to as a sub-scanning direction, and a direction perpendicular to the sub-scanning direction and parallel to the document P is referred to as a main scanning direction.

  An image to be read is printed on the document P. Although not shown in FIG. 9, the slider 101 includes a plurality of light sources that emit light of red, green, and blue, an equal-magnification lens, and a CCD (Charge Coupled Device). As shown in FIG. 9, the slider 101 reads an image of the document P while moving at a constant speed v in the sub-scanning direction. Specifically, the slider 101 sequentially irradiates red, green, and blue light on the document P while moving at a constant speed v. The CCD sequentially takes images for one line of red, green, and blue.

  However, in the light source switching type image reading apparatus, images are taken line by line in the order of red, green, and blue while the slider 101 moves at a constant speed v. Therefore, the shooting position RL where the red image is shot, the shooting position GL where the green image is shot, and the shooting position BL where the blue image is shot are shifted by 1/3 pixel as shown in FIG. End up. As a result, color misregistration occurs in the image read by the image reading apparatus.

Patent Document 1 describes an image reading apparatus for reading an image of a document with a curved reading surface or a wrinkled document. In the image reading apparatus, the focus of the liquid lens is made coincident with the reading surface of the document. However, Patent Document 1 does not describe an image reading device for eliminating color misregistration.
JP 2006-254132 A

  Accordingly, an object of the present invention is to provide an image reading apparatus that reads a color image by sequentially irradiating light of a plurality of colors, and can provide an image reading apparatus that can suppress occurrence of color misregistration in the read image. is there.

  According to the present invention, in the image reading apparatus, a slider that moves in a predetermined direction along the document surface and the slider are mounted on the slider, and light of different colors is sequentially applied to the document while the slider is moving. A plurality of light sources for irradiating; a photographing means for photographing an image of the document by light reflected from the document when the slider is positioned at the first photographing position and the second photographing position; and a reflection from the document An optical path changing means for changing the optical path of the light, and when the slider is located at the second imaging position, the optical path changing means is configured such that the second imaging position is greater than the first imaging position. When the optical path is also located upstream in the predetermined direction, the optical path is moved upstream in the predetermined direction, and the second imaging position is in the predetermined direction with respect to the first imaging position. When positioned on the downstream side, moving the optical path on the downstream side of the predetermined direction, characterized by.

  According to the present invention, when the slider is positioned on the upstream side from the first photographing position, the optical path changing unit moves the optical path of the light reflected from the document to the upstream side, so that the first photographing position is reached. If the downstream side is located, the optical path changing means moves the optical path of the light reflected from the document to the downstream side. For this reason, even when the slider is positioned upstream of the first shooting position, the light reflected at the first shooting position of the document is incident on the shooting means. Further, even when the slider is positioned downstream of the first photographing position, the light reflected at the first photographing position of the document enters the photographing unit. Thereby, the light incident on the photographing means becomes light reflected at substantially the same position of the document regardless of which of the plurality of light sources is turned on. As a result, the occurrence of color misregistration in the image reading apparatus is suppressed.

  In the present invention, a plurality of the first shooting positions are arranged at equal intervals in the predetermined direction, and a plurality of the second shooting positions are arranged in the predetermined direction so as to correspond to the first shooting positions. You may go out.

  In the present invention, the optical path changing means is a liquid lens including a first liquid and a second liquid, and a shape of an interface between the first liquid and the second liquid is deformed by an electrowetting phenomenon. By doing so, the optical path may change.

  In the present invention, the optical path changing means further includes a first electrode and a second electrode for applying a voltage to the first liquid and the second liquid, and the interface includes the first liquid and the second electrode. By applying different voltages to the electrode and the second electrode, the electrode may be deformed into an asymmetric shape with respect to the optical axis of the liquid lens.

  In the present invention, the first electrode and the second electrode may be arranged so as to sandwich an optical path of light reflected from the original.

  Hereinafter, an image reading apparatus according to an embodiment of the present invention will be described with reference to the drawings.

(Configuration of image reading device)
FIG. 1 is a side view of an image reading apparatus 10 according to an embodiment of the present invention. FIG. 2 is a perspective view of the inside of the slider 16 mounted on the image reading apparatus 10.

  The image reading apparatus 10 is an apparatus that reads an image of the original P by irradiating the original P with light and receiving light reflected from the original P. As shown in FIG. 12, a platen glass 14, a slider 16, and a control unit 32. The image reading apparatus 10 is an apparatus that adopts a so-called contact image sensor method. Hereinafter, the moving direction of the slider 16 is defined as the sub-scanning direction (x-axis direction), and the direction orthogonal to the sub-scanning direction and parallel to the document P is defined as the main scanning direction (y-axis direction).

  The image reading device main body 12 is a housing of the image reading device 10 and stores a slider 16 and a control unit 32 therein. Furthermore, the upper surface of the image reading apparatus main body 12 is opened, and a platen glass 14 is fitted in the opening. The platen glass 14 is made of transparent glass or resin, and the document P is placed on the upper surface thereof.

  The slider 16 moves at a constant speed along the surface of the document P in the direction of the arrow in FIG. 1 to read the image of the document P, and the slider body 18, light sources 20R, 20G, 20B, light guide plate 22, and equal magnification lens. 24, a light receiving element 26, a liquid lens 28, and a substrate 30. The slider body 18 is a housing of the slider 16 and stores therein the light sources 20R, 20G, and 20B, the light guide plate 22, the equal magnification lens 24, the light receiving element 26, the liquid lens 28, and the substrate 30. Furthermore, the upper surface of the slider body 18 is open.

  The light sources 20 </ b> R, 20 </ b> G, and 20 </ b> B are configured by, for example, LEDs (Light Emitting Diodes) and are mounted on the slider 16. Specifically, the light sources 20R, 20G, and 20B are attached to one end of a light guide plate 22 that extends in the y-axis direction, as shown in FIG. The light sources 20R, 20G, and 20B may be provided at both ends of the light guide plate 22. The light sources 20R, 20G, and 20B function as light sources that sequentially irradiate the original P with light of different colors. Specifically, the light source 20R irradiates the original P with red light. The light source 20G irradiates the original P with green light. The light source 20B irradiates the original P with blue light.

  As shown in FIG. 2, the light guide plate 22 has a shape having a longitudinal direction in the y-axis direction, and guides light incident from one end to the document P side. At this time, the light guide plate 22 diffuses the light in the light guide plate 22 so that luminance unevenness does not occur in the light applied to the document P.

  The light emitted from the light guide plate 22 passes through the platen glass 14 and irradiates the original P. Further, the light emitted from the light guide plate 22 is reflected by the original P and enters the equal magnification lens 24. As shown in FIG. 2, the equal-magnification lens 24 has a shape having a longitudinal direction in the y-axis direction, and forms an optical element on the light-receiving surface of the light-receiving element 26 at an equal magnification. It is.

  The light receiving element 26 functions as a photographing unit that captures an image of the document P by light reflected from the document P. The light receiving element 26 is constituted by a CCD (Charge Coupled Devices), for example, and is an element that generates an electric signal according to the intensity of incident light. In the present embodiment, the light receiving element 26 receives the light reflected by the document P and generates an electrical signal corresponding to the intensity of the light. As shown in FIG. 2, the light receiving element 26 has a shape having a longitudinal direction in the y-axis direction and a width of one pixel in the x-axis direction. That is, in the light receiving element 26, the pixels are arranged in a line so as to extend in the y-axis direction.

  The liquid lens 28 is provided between the equal-magnification lens 24 and the light receiving element 26 and plays a role of changing the optical path of the light reflected from the document P. Specifically, the liquid lens 28 moves the optical path of the light reflected from the document P to the upstream side or the downstream side in the traveling direction (x-axis direction) of the slider 16. As shown in FIG. 2, the liquid lens 28 has a shape having a longitudinal direction in the y-axis direction. Thereby, the equal-magnification lens 24, the liquid lens 28, and the light receiving element 26 are arranged so as to be parallel to each other in this order from above.

  The substrate 30 is a circuit board for controlling operations of the light sources 20R, 20G, and 20B, the light receiving element 26, and the liquid lens 28. The control part 32 is comprised by CPU, for example, and controls operation | movement of light source 20R, 20G, 20B, the light receiving element 26, and the liquid lens 28. FIG. With the configuration described above, the image reading apparatus 10 reads an image of the document P.

(Configuration of liquid lens)
Next, the configuration of the liquid lens 28 will be described with reference to the drawings. 3 and 5 are cross-sectional structural views of a plane parallel to the optical axis of the liquid lens 28. FIG. 4 is an enlarged view of a portion C of the liquid lens 28 in FIG.

  As shown in FIG. 2, the liquid lens 28 includes a conductive liquid 40, an insulating liquid 42, transparent plates 44 and 46, electrodes 48R and 48L, insulating films 50R and 50L, and electrodes 52R and 52L. The liquid lens 28 can change the shape of the interface S between the conductive liquid 40 and the insulating liquid 42 by an electrowetting phenomenon. Specifically, when a voltage is applied to the electrodes 48R, 48L, 52R, and 52L, the interface S is deformed from the state shown in FIG. 2B to the state shown in FIG.

  The transparent plates 44 and 46 are made of transparent resin or glass, and are arranged in parallel with each other leaving a predetermined gap. In this gap, the conductive liquid 40 and the insulating liquid 42 are sealed.

  The conductive liquid 40 is an inorganic salt aqueous solution, an organic liquid, or the like that has its own conductivity, or a liquid that is made conductive by adding an ionic component. The insulating liquid 42 is a liquid that has a refractive index different from that of the conductive liquid 40 and does not mix with the conductive liquid 40. Therefore, the conductive liquid 40 and the insulating liquid 42 are separated from each other, and form the interface S. Thus, the conductive liquid 40 and the insulating liquid 42 constitute a lens. Note that the refractive index of the conductive liquid 40 is preferably smaller than the refractive index of the insulating liquid 42.

  The electrodes 48R and 48L are provided on the transparent plate 44 so as to be in contact with the conductive liquid 40. Specifically, the electrodes 48R and 48L are opposed to each other with the optical path of the light reflected from the document P interposed therebetween, and are formed to extend in the y-axis direction in FIG. The electrodes 52R and 52L are provided between the transparent plate 46 and the electrodes 48R and 48L, respectively. Specifically, the electrodes 52R and 52L are opposed to each other across the optical path of the light reflected from the document P, and are formed to extend in the y-axis direction in FIG.

  The insulating films 50R and 50L are formed so as to cover the electrodes 52R and 52L, respectively. Specifically, the insulating films 50R and 50L are formed between the electrodes 48R and 48L and the electrodes 52R and 52L, respectively, and insulate the electrodes 48R and 48L from the electrodes 52R and 52L. The electrodes 52R, 52L are formed on the inner peripheral surface so that the conductive liquid 40 and the insulating liquid 42 do not come into contact with each other. A voltage is applied between the electrodes 48R and 48L and the electrodes 52R and 52L when the liquid lens 28 is driven. The electrode 48R and the electrode 48L are provided separately, and the electrode 52R and the electrode 52L are provided separately, whereby the voltage applied between the electrode 48R and the electrode 52R, the electrode 48L and the electrode 52L It becomes possible to control the voltage applied between them independently.

  The operation principle of the liquid lens 28 configured as described above will be described below with reference to FIG. 4 is an enlarged view of a portion C of the liquid lens 28 in FIG. 4A is an enlarged view of a portion C of the liquid lens 28 (corresponding to FIG. 3B) in a state where no voltage is applied, and FIG. 4B is a diagram in which voltage is applied. FIG. 4 is an enlarged view of a portion C of the liquid lens 28 (corresponding to FIG. 3A) in a state. In the following description, when referring to the individual electrodes 48R and 48L, the insulating films 50R and 50L, and the electrodes 52R and 52L, they are described as the electrodes 48R and 48L, the insulating films 50R and 50L, and the electrodes 52R and 52L. 48L, the insulating films 50R and 50L, and the electrodes 52R and 52L are collectively referred to as the electrode 48, the insulating film 50, and the electrode 52.

  First, the interfacial tension between the conductive liquid 40 and the insulating liquid 42 is set to an interfacial tension γ12, the interfacial tension between the insulating film 50 and the conductive liquid 40 is set to an interfacial tension γ31, and the insulating liquid 42 and the insulating film are set. The interfacial tension between 50 and 50 is defined as interfacial tension γ23. As shown in FIG. 4A, when no voltage is applied between the electrode 48 and the electrode 52, the interfacial tension γ12, the interfacial tension γ23, and the interfacial tension γ31 are balanced with each other, and the interface S And the insulating film 50 form an angle θ1. At this time, the relationship of the formula (1) is established by the Young's equation among the angle θ1, the interfacial tension γ12, the interfacial tension γ23, and the interfacial tension γ31.

  Here, when a voltage is applied to the electrode 48 and the electrode 52, for example, as shown in FIG. 4B, positive charges appear at the boundary between the insulating film 50 and the conductive liquid 40. On the other hand, negative charges appear at the boundary between the insulating film 50 and the electrode 52. As a result, a pressure drop due to the charge is generated between the insulating liquid 42 and the insulating film 50 in the same direction as the interfacial tension γ23. This pressure Π is expressed as in equation (2).

  Here, ε is a dielectric constant of the insulating film 50, ε0 is a vacuum dielectric constant, e is a thickness of the insulating film 50, and V is a voltage between the electrode 48 and the electrode 52.

  Due to the occurrence of the pressure drop, the interface S and the insulating film 50 form an angle θ2 larger than the angle θ1. For example, when a voltage is applied between both the electrode 48R and the electrode 52R and between the electrode 48L and the electrode 52L, the interface S of the liquid lens 28 is as shown in FIG. Bend. This angle θ2 is expressed as in Expression (3).

  As described above, it can be understood that the angle formed between the interface S and the insulating film 50 is changed by changing the voltage applied between the electrode 48 and the electrode 52. When the angle formed between the interface S and the insulating film 50 is changed, a voltage is applied between both the electrode 48R and the electrode 52R and between the electrode 48L and the electrode 52L. FIG. As shown, the interface S is curved, and the focal length is relatively short. Also, in the state where no voltage is applied between the electrode 48R and the electrode 52R and between the electrode 48L and the electrode 52L, the interface S becomes flat as shown in FIG. The distance becomes relatively long.

  Furthermore, when different voltages are applied between the electrode 48R and the electrode 52R and between the electrode 48L and the electrode 52L, the interface S is deformed into an asymmetric shape with respect to the optical axis of the liquid lens 28. Specifically, in a state where a voltage is applied only between the electrode 48R and the electrode 52R, as shown in FIG. 5A, the interface S is lowered from the electrode 52L side to the electrode 52R side. To tilt. In this case, the optical path of the light incident on the liquid lens 28 is moved from the electrode 52R side to the electrode 52L side as shown in FIG.

  On the other hand, when a voltage is applied only between the electrode 48L and the electrode 52L, the interface S is inclined so as to decrease from the electrode 52R side toward the electrode 52L side as shown in FIG. 5B. To do. In this case, the optical path of the light incident on the liquid lens 28 is moved from the electrode 52L side to the electrode 52R side as shown in FIG.

(Operation of image reader)
Hereinafter, the operation of the image reading apparatus 10 will be described with reference to the drawings. 6 and 7 are side views of the image reading apparatus 10. In FIG. 6, the slider 16 is positioned on the upstream side in the x-axis direction by 1/3 pixel from the image reading apparatus 10 of FIG. In FIG. 7, the slider 16 is positioned on the downstream side in the x-axis direction by 1/3 pixel from the image reading apparatus 10 of FIG. 6 and 7, the amount of movement of the slider 16 is shown larger than usual for easy understanding.

  In the image reading apparatus 10, the light sources 20 </ b> R, 20 </ b> G, and 20 </ b> B irradiate the original P with light when the slider 16 is positioned at each of the shooting positions RL, GL, and BL shown in FIG. 9. The light receiving element 26 captures an image of one line of the document P at the timing when each of the light sources 20R, 20G, and 20B emits light. At this time, in the image reading apparatus 10, the liquid lens 28 moves the optical path of the light reflected from the document P to the upstream side or the downstream side in the x-axis direction. Here, when the slider 16 is positioned at the shooting positions RL, GL, and BL, the light reflected at the shooting positions RL, GL, and BL of the document P passes through the liquid lens 28 in the state shown in FIG. It refers to the position of the slider 16 when entering the light receiving element 26. Since the slider 16 moves at a constant speed, a plurality of shooting positions GL are arranged at equal intervals in the x-axis direction as shown in FIG. The shooting position RL is located upstream of the shooting position GL so as to correspond to the shooting position GL. The shooting position BL is located on the downstream side of the shooting position GL so as to correspond to the shooting position BL.

  Hereinafter, the operation of the image reading apparatus 10 will be described in detail. FIG. 8 is a waveform diagram of operation signals of the image reading apparatus 10. FIG. 8A shows the drive signal LEDR for the light source 20R. FIG. 8B shows the drive signal LEDG for the light source 20G. FIG. 8C shows a drive signal LEDB for the light source 20B. 8A to 8C, the light sources 20R, 20G, and 20B are turned off when the drive signals LEDR, LEDG, and LEDB are at a low level, and the light sources when the drive signals LEDR, LEDG, and LEDB are at a high level. 20R, 20G, and 20B are lit. FIG. 8D is a diagram illustrating the drive signal SP generated by the control unit 32. FIG. 8E shows the drive signal SigL applied between the electrode 48L and the electrode 52L. FIG. 8F shows a drive signal SigR applied between the electrode 48R and the electrode 52R.

  The control unit 32 raises the drive signal SP to the high level and outputs it to the substrate 30, lowers the drive signal SigL to the low level, and raises the drive signal SigR to the high level (time t <b> 1). Accordingly, as shown in FIG. 5A, the interface S of the liquid lens 28 is inclined so as to decrease from the electrode 52L side to the electrode 52R side. After a predetermined time has elapsed from time t1, the control unit 32 causes the drive signal LEDR to fall to a low level. Thereby, the light source 20R irradiates the original P with red light (time t2). At this time t2, as shown in FIG. 6, the slider 16 is located at a photographing position RL that is located upstream of the photographing position GL in the x-axis direction. Further, at time t2, the liquid lens 28 moves the optical path of the light reflected by the document P to the upstream side in the x-axis direction. As a result, the light reflected at the photographing position GL of the original P enters the light receiving element 26.

  The light source 20R is lit for a predetermined time from the time t2. Therefore, the light receiving element 26 captures a red image for one line at the photographing position GL of the document P during the period when the light source 20R is turned on.

  Next, the control unit 32 raises the drive signal SP to the high level, outputs it to the substrate 30, and lowers the drive signal SigR to the low level (time t3). At this time, the light receiving element 26 outputs a red image signal for one line to the control unit 32. Further, as shown in FIG. 3B, the interface S of the liquid lens 28 becomes flat. After a predetermined time has elapsed from time t3, the control unit 32 causes the drive signal LEDG to fall to a low level. Thereby, the light source 20G irradiates the original P with green light (time t4). At this time t4, the slider 16 is located at the photographing position GL as shown in FIG. Since the liquid lens 28 does not move the optical path of the light reflected by the document P, the light reflected at the photographing position GL of the document P is incident on the light receiving element 26.

  The light source 20G is lit for a predetermined time from time t4. Therefore, the light receiving element 26 captures a green image for one line at the photographing position GL of the document P during the period when the light source 20G is turned on.

  The control unit 32 raises the drive signal SP to the high level, outputs it to the substrate 30, and raises the drive signal SigL to the high level (time t5). At this time, the light receiving element 26 outputs a green image signal for one line to the control unit 32. Further, as shown in FIG. 5B, the interface S of the liquid lens 28 is inclined so as to decrease from the electrode 52R side toward the electrode 52L side. After a predetermined time has elapsed from time t5, the control unit 32 causes the drive signal LEDB to fall to a low level. Thereby, the light source 20B irradiates the original P with blue light (time t6). At this time t6, as shown in FIG. 7, the slider 16 is located at the photographing position BL located downstream of the photographing position GL in the x-axis direction. Further, at time t6, the liquid lens 28 moves the optical path of the light reflected by the document P to the downstream side in the x-axis direction. As a result, the light reflected at the photographing position GL of the original P enters the light receiving element 26.

  The light source 20B is lit for a predetermined time from time t6. Therefore, the light receiving element 26 captures a blue image for one line at the photographing position GL of the document P during the period when the light source 20B is turned on. Thereafter, the control unit 32 raises the drive signal SP to a high level and outputs it to the substrate 30 (time t7). At this time, the light receiving element 26 outputs a blue image signal for one line to the control unit 32. Through the operations from time t1 to time t7 as described above, the control unit 32 obtains red image data, green image data, and blue image data for each line. Further, while the slider 16 is moving along the document P surface, the control unit 32 acquires the image data of the document P by repeating the operations from time t1 to time t7.

(effect)
According to the image reading device 10, when the slider 16 is positioned upstream from the shooting position GL, the liquid lens 28 moves the optical path of the light reflected from the document P to the upstream side, and from the shooting position GL. However, when the slider 16 is positioned on the downstream side, the optical path of the light reflected from the original P by the liquid lens 28 is moved downstream. For this reason, even when the slider 16 is positioned upstream of the shooting position GL, the light reflected at the shooting position GL of the document P is incident on the light receiving element 26. Even when the slider 16 is positioned downstream of the shooting position GL, the light reflected at the shooting position GL of the document P is incident on the light receiving element 26. Thereby, the light incident on the light receiving element 26 is reflected at the same position on the original P regardless of which of the light sources 20R, 20G, and 20B is lit. As a result, occurrence of color misregistration in the image reading apparatus 10 is suppressed.

(Other embodiments)
The image reading apparatus 10 according to the present invention is not limited to the above-described embodiment, and can be changed within the scope of the gist. For example, the liquid lens 28 is not limited to one having an elongated shape as shown in FIG. For example, a plurality of small liquid lenses 28 may be arranged in the y-axis direction. In this case, each liquid lens 28 is preferably provided with an electrode 48 and an electrode 52. As a result, each liquid lens 28 can be controlled independently, and the amount of color misregistration can be controlled according to the position in the y-axis direction. Furthermore, since it is not necessary to drive the unnecessary liquid lens 28, the power consumption of the image reading apparatus 10 can be reduced.

  In the image reading device 10, three light sources 20R, 20G, and 20B are used as light sources, but the number of light sources is not limited to this. It is sufficient that at least a plurality of light sources are provided.

  In the image reading apparatus 10, the liquid lens 28 is used as the optical path changing means, but the optical path changing means is not limited to this. For example, instead of the liquid lens 28, a transparent plate such as a glass plate may be provided between the equal magnification lens 24 and the light receiving element 26. Then, the optical path of the light reflected by the original P is changed by changing the inclination of the transparent plate.

1 is a side view of an image reading apparatus according to an embodiment of the present invention. It is a perspective view inside a slider mounted on an image reading device. It is a cross-sectional structure figure in a surface parallel to the optical axis of a liquid lens. FIG. 4 is an enlarged view of a portion C of the liquid lens in FIG. 3. It is a cross-sectional structure figure in a surface parallel to the optical axis of a liquid lens. It is a side view of an image reading apparatus. It is a side view of an image reading apparatus. It is a wave form diagram of an operation signal of an image reading device. It is explanatory drawing for demonstrating that color shift generate | occur | produces in the image read by the light source switching system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Image reader 12 Image reader main body 14 Platen glass 16 Slider 18 Slider main body 20R, 20G, 20B Light source 22 Light guide plate 24 1x lens 26 Light receiving element 28 Liquid lens 30 Substrate 32 Control part 40 Conductive liquid 42 Insulating liquid 48 , 48L, 48R, 52, 52L, 52R Electrode RL, GL, BL Shooting position P Document S Interface

Claims (5)

A slider that moves in a predetermined direction along the document surface,
A plurality of light sources mounted on the slider and sequentially irradiating the original with different colors of light while the slider is moving;
Photographing means for photographing an image of the document by light reflected from the document when the slider is located at the first photographing position and the second photographing position;
Optical path changing means for changing the optical path of the light reflected from the original;
With
In the case where the slider is located at the second imaging position, the optical path changing means is configured to change the optical path when the second imaging position is located upstream of the first imaging position in the predetermined direction. The optical path is moved to the upstream side in the predetermined direction and the optical path is moved to the downstream side in the predetermined direction when the second imaging position is located downstream of the first imaging position in the predetermined direction. ,
An image reading apparatus characterized by the above. A plurality of the first photographing positions are arranged at equal intervals in the predetermined direction,
A plurality of the second shooting positions are arranged in the predetermined direction so as to correspond to the first shooting positions;
The image reading apparatus according to claim 1. The optical path changing means is a liquid lens containing a first liquid and a second liquid,
The optical path is changed by the shape of the interface between the first liquid and the second liquid being deformed by an electrowetting phenomenon;
The image reading apparatus according to claim 1, wherein: The optical path changing means is
A first electrode and a second electrode for applying a voltage to the first liquid and the second liquid;
In addition,
The interface is deformed into an asymmetric shape with respect to the optical axis of the liquid lens by applying different voltages to the first electrode and the second electrode,
The image reading apparatus according to claim 3. The first electrode and the second electrode are disposed so as to sandwich an optical path of light reflected from the document;
The image reading apparatus according to claim 4.

Images