JP3936437B2 - Image sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is an image sensor used in an image reading unit or an image scanner device of a facsimile machine. To Related.
[0002]
[Prior art]
An example of a conventional image sensor 1 is shown in FIG. This image sensor 1 is configured as a so-called close contact type image sensor 1, and a plurality of image sensor chips are arranged in a length range corresponding to an image reading width at a bottom portion of a case 10 formed of resin or the like. A substrate 2 on which a light source 21 composed of 20 and LED chips is mounted is mounted, and a transparent cover 5 made of glass or the like is fitted into the upper opening 11 of the case 10. In the internal space 13 between the reading line L set on the transparent cover 5 and the light source 21, a light guide member 3 for efficiently guiding the light emitted from the light source 21 to the reading line L is disposed. ing. Further, a lens for converging a bright and dark image along the reading line L on the image sensor chip 20 at an equal magnification between the reading line L set on the transparent cover 5 and the image sensor chip 20. An array 4 is arranged.
[0003]
That is, in the image sensor 1, the light emitted from the light source 21 reaches the taking line L via the light guide member 3 to illuminate the original D, and the reflected light from the original D passes through the lens array 4. The image sensor chip 20 is configured to receive light. In the light guide member 3, light emitted from the light source 21 enters the light guide member 3 from the light incident surface 30, and this light is totally reflected at the boundary surface 32 between the light guide member 3 and the outside. While traveling through the light guide member 3 and reaching the light exit surface 31, the light is emitted from the light exit surface 31 to illuminate the document D.
[0004]
[Problems to be solved by the invention]
However, in the image sensor 1 configured as described above, the light guide member 3 is disposed in the internal space 13 of the case 10 so that the light from the light source 21 is more efficient than the case where the light guide member 3 is not disposed. Although the original D can be illuminated well, a part of the light guided to the light guide member 3 leaks from the boundary surface 32 to the outside of the light guide member 3 without being totally reflected at the boundary surface 32. End up. That is, light incident on the boundary surface 32 at an angle smaller than the total reflection critical angle passes through the boundary surface 32 and leaks to the outside of the light guide member 3. Since most of such light is absorbed by the inner wall of the case 10, the light leaking from the boundary surface 32 cannot be used effectively in the image sensor 1 having the above configuration.
[0005]
By the way, when manufacturing the image sensor 1, it is preferable that the number of the light sources 21 mounted on the substrate 2 is small from the viewpoint of reducing the manufacturing cost, and for driving the image sensor 1 at a low voltage. However, it is preferable that the number of the light sources 21 is small. The problem in this case is how to compensate for the decrease in the amount of light emitted from the entire light source accompanying the reduction in the number of light sources 21. However, in the image sensor 1 having the above-described configuration, the light emitted from the light source 21 is effectively used to some extent by adopting the light guide member 3, but between the light guide member 3 and the outside. As described above, part of the light guided from the boundary surface 32 into the light guide member 3 leaks, and the number of the light sources 21 is reduced and the image sensor 1 is driven as desired to prepare the document. It is difficult to read an image.
[0006]
The present invention has been conceived under the circumstances described above, and an object thereof is to efficiently guide light emitted from a light source to a document.
[0007]
DISCLOSURE OF THE INVENTION
In order to solve the above problems, the present invention takes the following technical means.
[0008]
That is, from this application Clearly More provided Image sensor Is A light source, a light guide member for reading the light emitted from the light source to guide the original, and a light converging member for converging the reflected light from the original, and these are accommodated in the case In the image sensor, the light guide member includes a reflecting member in which at least a part of a boundary surface with the outside excluding the light incident surface and the light emitting surface is formed of a white resin having excellent light reflectance. In the state where the pin is formed in close contact with the pin hole and fitted into the case, it is fitted and placed in the case from above. It is characterized by that.
[0010]
Since the reflection member is formed of a white resin, it can be easily formed into a desired shape, for example, by molding. That is, if the mold is appropriately designed, the protrusions and pins protruding from the predetermined part can be integrally formed at the same time, and the recessed portion can be easily formed. For this reason, if the recessed part which can fit a protrusion etc. which were formed in the said reflective member, for example is formed in the said light guide member, the said reflective member and light guide member can be integrated easily. . Therefore, the reflective member can be brought into close contact with and integrated with the light guide member with high accuracy without using an adhesive or the like. Reflecting member and light guide unit integrated in this way Material Its handling is easy , Tree It can be easily accommodated and placed in the case while maintaining a close contact state, for example, by press-fitting into a holder or the like that is recessedly formed in the case such as a fat.
[0011]
By the way, in the image sensor in which the light guide member is accommodated, the light source Or The light emitted from the light incident surface and incident on the light guide member travels while being reflected by the boundary surface between the light guide member and the outside, and is emitted from the light exit surface to illuminate the document. A part of the light traveling in the light guide member does not reflect on the boundary surface and leaks to the outside of the light guide member. Is As described above. In the present invention, since the reflecting member is in close contact with at least a part of the boundary surface with the outside of the light guide member, light traveling inside the light guide member leaks to the outside of the light guide member. Even if the light is lost, the light leaking from the boundary surface to which the reflecting member is brought into close contact is reflected by the reflecting member, returned to the light guide member, and travels again in the light guide member. As a result, even if the light once leaks to the outside of the light guide member, the light returned from the light guide member by the reflecting member is emitted from the light emitting surface. That is, the above structure To complete In the provided image sensor, the light emitted from the light source can be efficiently emitted from the light exit surface to illuminate the original. Therefore, the above configuration No According to the image sensor, the light emitted from one light source can be efficiently guided to the reading line of the document, so that a desired image can be read by reducing the number of light sources. As a result, the manufacturing cost can be reduced and the image can be reduced. Low voltage driving of the sensor can be realized.
[0012]
Needless to say, the reflecting member may be in close contact with the entire boundary surface, or may be in close contact with a portion where boundary surface light is likely to leak, and may be in close contact with any portion of the boundary surface. What is necessary is just to design suitably.
[0017]
In a preferred embodiment, light that is emitted from the light exit surface of the light guide member and that is not directly guided to the document is guided to the document by changing its path. The reflector is accommodated and disposed so as to extend upward from the upper part of the light focusing member.
[0018]
According to the above configuration, the original can be illuminated by changing the course of the light that is incident from the light incident surface and is not directly guided to the original but is wasted by the reflector. it can. That is, in the image sensor having the above configuration, in addition to being able to efficiently emit light emitted from the light source to the light guide member from the light emitting surface, the light emitted from the light emitting surface is efficiently read. Can lead to the line. Thus, by arranging the reflector in a predetermined position, it is possible to increase the effect obtained by closely arranging the reflective member to the light guide member.
[0019]
In a preferred embodiment, the light guide member and the reflection member are integrated by a fitting means, and the reflection member and / or the light guide member and the case are integrated by a fitting means. You may comprise.
[0020]
As described above, as described above, the light guide member and the reflection member are integrated, that is, the light guide unit is handled easily as described above. In the above configuration, the work of using the light guide member and the reflection as the light guide unit by the fitting means is extremely easy, and in the state of the light guide unit, the light guide member and the reflection member formed separately from each other are provided. The members do not need to be accommodated and arranged in the case, and an integrated light guide unit may be accommodated and arranged. This simplifies the labor for manufacturing the image sensor. Such an effect is prominent when the number of the reflecting members is large.
[0021]
In a preferred embodiment, the image sensor has an upper opening formed in the case, and a transparent cover is fitted into the opening, and the original image is read by feeding the original over the transparent cover. In addition, the image may be read by illuminating light while scanning a fixed document.
[0022]
The image sensor with the former configuration is configured as a so-called contact image sensor for sheet feed, and the image sensor with the latter configuration is configured as a so-called flat bed image sensor. That is, the present invention described so far can be applied to both the sheet-feed type contact image sensor and the flat bed image sensor, and it goes without saying that these image sensors can enjoy the various effects described above. Nor.
[0023]
Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.
[0024]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.
[0025]
FIG. 1 shows the present invention. Used for image sensors FIG. 2 is an exploded cross-sectional view illustrating an example of a light guide unit, FIG. 2 is a cross-sectional portion illustrating a main part of the light guide unit 6, and FIG. 3A is a light guide member that configures the light guide unit 6. 3 (b) is a front view thereof, FIG. 4 (a) is a plan view of the first reflecting member 7 constituting the light guide unit 6, and (b) is a plan view thereof. FIG. 5A is a front view, FIG. 5A is a plan view of the second reflecting member 8 constituting the light guide unit 6, and FIG. 5B is a front view thereof. In addition, the same code | symbol is attached | subjected to the same thing as the member and element currently drawn on drawing referred in order to demonstrate a prior art example.
[0026]
As shown in FIG. 1, the light guide unit 6 includes a light guide member 3, and a first reflective member 7 and a second reflective member 8 that are attached so as to be in close contact with the light guide member 3. These members 3, 7, and 8 are integrated by a predetermined fitting means.
[0027]
As shown in FIGS. 1 and 3, the light guide member 3 is formed in an elongated bar shape having a light incident surface 33 and a light output surface 34 by molding an acrylic transparent resin such as PMMA. The light guide member 3 has a longitudinal direction To A first side surface 3a, a second side surface 3b, a third side surface 3c, and a fourth side surface 3d are formed, respectively, so that the first to third side surfaces 3a to 3c, the light incident surface 33, and the light incident surface 33 are formed. Are mirror-like, and the fourth side surface 3d is an irregular reflection surface. In addition, the end side surfaces 3e and 3e in the longitudinal direction of the light guide member 3 are light reflecting surfaces on which light is not easily transmitted by appropriate means.
[0028]
The mirror surface is not limited to the case where the surface is actively polished, but also refers to a relatively smooth surface obtained when the light guide member 3 is formed by molding, for example. Included in specular surfaces. If the surface of the transparent member is mirror-like, light incident on this surface at an angle larger than the total reflection critical angle specified by the material of the transparent member can be totally reflected, and the total reflection critical angle is Light incident at a smaller angle can pass through the surface. Further, the fourth side surface 3d is a diffusely reflecting surface by providing irregularities by, for example, painting the fourth side surface 3d with a white paint or forming a plurality of slits extending in the width direction on the fourth side surface 3d. It is said that.
[0029]
As clearly shown in FIG. 3, the central portion in the longitudinal direction of the light emitting surface 34 of the light guide member 3 is recessed in a substantially V shape when viewed from the front, and two inclined surfaces 32 and 32 are formed. Has been. Of course, these inclined surfaces 32 and 32 are also mirror-like. The first side surface 3a includes Extends horizontally A plurality of pinholes 30 are formed, and two fins 31 and 31 are formed on the fourth side surface 3d so as to face each other, and a surface between the two fins 31 and 31 is formed. The light incident surface 33 is used. As will be described later, the pinhole 30 and the fin 31 constitute a fitting means, and the light guiding member 3 and the first reflecting member 7 are connected to the light guiding member 3 and the above by the fitting means. The second reflecting member 8 is integrated with each other.
[0030]
As shown in FIGS. 1 and 4, the first reflecting member 7 is formed in an elongated bar shape as a whole by molding, for example, a white resin having excellent reflectance. The first reflecting member 7 has end convex portions 73 and 73 formed at both ends in the longitudinal direction thereof, and the central convex portion 72 and the two light shielding plates 70 and 70 protrude from the central portion, respectively. A plurality of insertion pins 71 are formed corresponding to the pinholes 30 formed in the light guide member 3 (see FIG. 6 described later). The insertion pins 71 are inserted and fitted into the pinholes 30 of the light guide member 3 so that the first reflection member 7 is integrated with the light guide member 3. The reflection member 7 is in close contact with the first and second side surfaces 3a and 3b of the light guide member 3. The light guide unit 6 is housed and arranged in a case 10 made of resin, which will be described later, and constitutes an image sensor. However, the end protrusions 73 and 73 and the center protrusion 72 are formed on the case 10. The light guide unit 6 is held and fixed in the case 10 by being fitted into the formed side recesses 14 and 14 and the center recess 14A. As clearly shown in FIG. 2, the light shielding plates 70, 70 are V at the center of the light guide member 3 in a state where the first reflecting member 7 and the light guide member 3 are integrated. It is designed to cover the part that is recessed in the shape of a letter. That is, as will be described later, when the light guide unit 6 is incorporated in the case 10, the light source 21 is positioned substantially vertically below the light shielding plates 70 and 70, as indicated by phantom lines in FIG. 2. However, if the light shielding plates 70 and 70 are arranged so as to be located in such a portion, the light emitted from the light source 21 is concentrated and emitted from the central portion of the light guide member 3. Can be avoided.
[0031]
As shown in FIGS. 1 and 5, the second reflecting member 8 is formed in the shape of an elongated bar as a whole by molding, for example, a white resin having excellent reflectance, like the first reflecting member 7. A through hole 80 penetrating vertically is formed at the center in the longitudinal direction. As clearly shown in FIG. 2, the fins 31, 31 formed on the light guide member 3 are fitted into the through hole 80, and the second reflection member 8 and the light guide member 3 are integrated. Thus, the third and fourth side surfaces 3 c and 3 d of the light guide member 3 are brought into close contact with the second reflecting member 8. The means for integrating the second reflecting member 8 and the light guide member 3 is not limited to the above-described means, and the design can be changed as appropriate. Further, when the light guide unit 6 is incorporated in the case 10, the light source 21 faces the through hole 80, and the light emitted from the light source 21 is directly applied to the light guide member 3. The light incident surface 33 is irradiated.
[0032]
Each of the reflecting members 7 and 8 is formed by molding, for example, as described above. However, when molding is performed by molding, the reflecting members 7 and 8 are easily formed into a desired shape. be able to. In addition, each of the reflecting members 7 and 8 and the light guide member 3 are formed with elements as fitting means, and can be guided to the reflecting members 7 and 8 by an extremely easy operation of fitting them. The optical member 3 can be integrated. Therefore, in the above configuration, the reflecting members 7 and 8 can be brought into close contact with and integrated with the light guide member 3 with high accuracy without using an adhesive or the like. The reflecting members 7 and 8 and the light guide member 3, that is, the light guide unit 6, integrated in this way are easy to handle. The light sensor unit 6 is incorporated in the case 10 to incorporate an image sensor. The configuration is as described above. Hereinafter, an example of an image sensor in which the light guide unit 6 is incorporated will be described with reference to FIGS.
[0033]
6 is an exploded perspective view showing an example of the image sensor according to the present invention, FIG. 7 is an exploded sectional view of the image sensor 1, and FIG. 8 is a sectional view of the image sensor 1. FIG. 9 is a diagram illustrating a state of light incident on the light guide member 3 constituting the light guide unit 6. In the present embodiment, a configuration configured as the contact image sensor 1 will be described.
[0034]
As shown in FIGS. 6 to 8, the image sensor 1 has a case 10 made of resin or the like, and a plurality of image sensor chips 20 are provided at the bottom of the image sensor chip 20 within a length range corresponding to the image reading width. And the board | substrate 2 with which the light source 21 comprised by the LED chip etc. was mounted is attached. In the present embodiment, the image sensor 1 is configured to read the image of the read original D in black and white, and the light source 21 employs, for example, an LED chip that emits white light, thereby reducing manufacturing costs and the like. From that point of view, the number is one. Note that the substrate 2 is attached so that the two attachments 9 and 9 are fitted from the lower side of the case 10 and are locked to the engagement protrusions 15 and 15 provided on the outer surface of the case 10. It has been.
[0035]
As shown in FIG. 8, a transparent cover 5 made of glass or the like is fitted into the upper opening 11 of the case 10, and the interior between the reading line L set on the transparent cover 5 and the light source 21 is inside. In the space, the light guide unit 6 having the light guide member 3 for efficiently guiding the light emitted from the light source 21 to the reading line L is accommodated. The light guide unit 6 is accommodated and disposed in the case 10 in such a manner that a holder portion 19 formed in the internal space of the case 10 is fitted by means such as press fitting. As described above, the first reflective member 7 of the light guide unit 6 is formed with the central convex portion 72 and the end convex portions 73 and 73, respectively. The convex portions 72, 73, 73 are fitted into a central recessed portion 14 </ b> A and end recessed portions 14, 14 formed at the center portion and both end portions in the longitudinal direction of the holder portion 19, respectively. In this way, the convex portions 72, 73, 73 are fitted into the concave portions 14A, 14, respectively, so that the light guide unit 6 is positioned with high accuracy and in a simple and satisfactory manner. 10 can be retained.
[0036]
Further, a lens for converging a bright and dark image along the reading line L on the image sensor chip 20 at an equal magnification between the reading line L set on the transparent cover 5 and the image sensor chip 20. An array 4 is arranged. That is, in the image sensor 1, the light emitted from the light source 21 reaches the taking line L via the light guide member 3 to illuminate the original D, and the reflected light from the original D passes through the lens array 4. The image sensor chip 20 is configured to receive light.
[0037]
As clearly shown in FIG. 9, in the light guide member 3, the light emitted from the light source 21 enters the light guide member 3 from the light incident surface 33, and this light is incident on the light guide member 3. The light is totally reflected on the first, second, and third side surfaces 3a, 3b, 3c, the end side surface 3e, and the light emitting surface 34, and diffusely reflected on the fourth side surface 3d to travel through the light guide member 3. . In this process, light incident on the light emitting surface 34 at an angle equal to or smaller than the total reflection critical angle is transmitted without being reflected by the light emitting surface 34, and the transmitted light is emitted from the light emitting surface 34. Such light emission is performed on the entire light emission surface 34, and the amount of light emitted from each part of the light emission surface 34 is substantially uniform.
[0038]
The light guide unit 6 is in close contact with the first and second side surfaces 3a and 3b of the light guide member 3, and the first reflecting member 7 is in close contact with the third and fourth side surfaces 3c and 3d. As described above, the reflecting member 8 is attached and configured. Thus, since each said reflection member 7 and 8 is contact | adhered to the said light guide member 3, it permeate | transmitted the 1st-4th side surfaces 3a-3d of the said light guide member 3 without totally reflecting. The light is reflected on the surfaces of the reflecting members 7 and 8 and returned to the light guide member 3 again. That is, in the light guide member 3 having the above-described configuration, it is possible to reduce a problem that light incident from the light incident surface 33 leaks outside the light guide member 3 before being emitted from the light exit surface 34. The light emitted from the light source 21 can be efficiently guided to the reading line L. For this reason, even if only one light source 21 is provided as in the present embodiment, it is possible to perform desired image reading using the light emitted from the light source 21 effectively. Therefore, in the present invention, it is possible to realize the image sensor 1 that does not cause a problem even if the number of the light sources 21 incorporated in the image sensor 1 is reduced, and the cost required for manufacturing the image sensor 1. Can be reduced, and the manufactured image sensor 1 can be driven at a low voltage.
[0039]
In the present embodiment, the case where the light guide unit 6 in which the reflecting members 7 and 8 and the light guide member 3 are integrated is incorporated in the case 10, but these members 3, 7, and 8 are described. Even in the case where they are separately incorporated in the case 10, the reflecting members 7, 8 and the light guide member 3 are in close contact with each other, and the reflecting members 7 are assembled. , 8 are made of white resin, which is within the scope of the present invention.
[0040]
Moreover, in the said embodiment, although the two reflection members, the 1st reflection member 7 and the 2nd reflection member 8, were stuck to the said light guide member 3, it is not restricted to this, as shown in FIG. The configuration may be such that only the reflective member 7 a corresponding to the first reflective member 7 is closely attached to the light guide member 3 without having the second reflective member 8 in the above embodiment. Also in this case, since the first and second side surfaces 3a and 3b of the light guide member 3 are in close contact with the reflecting member 7a, the light emitted from the light source 21 can be efficiently guided to the document D. .
[0041]
In addition to this, as shown in FIG. 11, a reflector 7 </ b> A that is preferably formed in a longitudinal shape so as to extend from the upper portion of the lens array 4 may be disposed. Of course, the reflector 7A can also be formed of a white resin in the same manner as each of the reflecting members 7 and 8. However, the present invention is not limited to this, and a metal coating layer is formed on the surface of a predetermined member or a white paint The light reflecting surface may be formed by painting or the like. By the way, even if the light is emitted from the light exit surface 34 of the light guide member 3, a part of the light is absorbed by the inner wall of the case 10 without illuminating the read original D. If such a light is reflected by the reflector 7A and its path is changed to illuminate the read original D, the light emitted from the light source 21 can be used more efficiently.
[0042]
Further, as shown in FIG. 12, the image sensor 1 is an image sensor 1 in which the two reflecting members 7 and 8 described in the above embodiment are in close contact with the light guide member 3. The structure which employ | adopted the reflector 7A employ | adopted with the sensor 1 may be used.
[0043]
In addition, in the above embodiment, an example in which the present invention is applied to the contact image sensor 1 has been described. However, the technical idea described in the above embodiment irradiates light while scanning a fixed read original. Needless to say, the present invention can also be applied to a so-called flatbed image sensor configured to read an image of a document. As shown in FIG. 13, the basic configuration of the flatbed image sensor 1a can be substantially the same as that of the contact image sensor 1 described above. The configuration of the image sensor 1a is significantly different from that of the contact image sensor 1 in that the transparent cover 5 that covers the case 10 is not provided and the upper surfaces of the first reflecting member 7 and the lens array 4 are exposed. is there. The image sensor 1a configured as described above is incorporated in, for example, a housing (not shown) covered with a glass cover 5A, and is fixed on the glass cover 5A while scanning in the direction of arrow A in the figure. The document D is configured to illuminate. For example, when the image sensor 1a is configured to read the image of the document D line by line, the image sensor 1a illuminates the document while scanning in the sub-scanning direction of the document. It becomes. Also in the image sensor 1a that illuminates the document D while scanning as described above, when the first and second reflecting members 7 and 8 are provided, the first and second reflections as described in the above embodiment. Needless to say, the effects of providing the members 7 and 8 can be enjoyed.
[Brief description of the drawings]
[FIG. 1] In the present invention used It is an exploded sectional view showing an example of a light guide unit.
FIG. 2 is a cross-sectional view of a main part of the light guide unit.
FIG. 3A is a plan view of a light guide member constituting the light guide unit, and FIG. 3B is a front view thereof.
4A is a plan view of a first reflecting member constituting the light guide unit, and FIG. 4B is a front view thereof.
5A is a plan view of a second reflecting member constituting the light guide unit, and FIG. 5B is a front view thereof.
FIG. 6 is an exploded perspective view showing an example of an image sensor according to the present invention.
FIG. 7 is an exploded cross-sectional view of the image sensor.
FIG. 8 is a cross-sectional view of the image sensor.
FIG. 9 is a diagram illustrating a state of light incident in a light guide member constituting the light guide unit.
FIG. 10 is a cross-sectional view illustrating a modification of the image sensor according to the present invention.
FIG. 11 is a cross-sectional view showing another modification of the image sensor according to the present invention.
FIG. 12 is a cross-sectional view illustrating still another modification of the image sensor according to the present invention.
FIG. 13 is a cross-sectional view of an example in which the present invention is applied to a flatbed image sensor.
FIG. 14 is a cross-sectional view illustrating an example of an image sensor according to a conventional example.
[Explanation of symbols]
1 Image sensor (contact type)
1a Image sensor (for flatbed)
2 Substrate
3 Light guide member
4 Lens array
5 Transparent cover
6 Light guide unit
7 First reflective member
7A reflector
8 Second reflective member
10 cases
14 End recess (case)
14A Center recess (case)
20 Image sensor chip
21 Light source
30 pinhole
31 Fin (of the light guide member)
33 Light incident surface
34 Light exit surface
71 Insertion pin (as fitting means)
72 Center convex part (as fitting means)
73 End convex part (as fitting means)
D Scanned document
L reading line

Claims (4)

A light source, a light guide member for reading the light emitted from the light source to guide the original, and a light converging member for converging the reflected light from the original, and these are accommodated in the case An image sensor,
The light guide member includes a pin and a pin in which at least a part of a boundary surface with the outside excluding the light incident surface and the light output surface is formed of a reflective member formed of a white resin having excellent light reflectance in the horizontal direction. An image sensor, wherein the image sensor is placed and accommodated in the case from above while being in close contact with a hole . A reflector for guiding the light emitted from the light emitting surface of the light guide member and not directly guided to the document to the document by changing the path thereof is the light focusing member. The image sensor according to claim 1 , wherein the image sensor is accommodated and disposed so as to extend upward from an upper portion of the image sensor. An upper opening is formed in the case, and a transparent cover is fitted into the opening, and an image of a document is read by feeding the document over the transparent cover. The image sensor according to 1 or 2 . The image sensor according to any one of claims 1 to 3 , wherein the image sensor is configured to read an image of a document by illuminating light while scanning a fixed document.

Images