JP2006287923A - Linear lighting system and image reader using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase lighting intensity of illumination emitting from a linear lighting system and to provide a linear lighting system with more uniformed illumination distribution along the longitudinal direction of a light guiding body. <P>SOLUTION: A linear lighting system has a light guide having LEDs located on a light entrance on one end of a light guiding body made with a transmissive and longitudinal member for guiding incoming light from its entrance in longitudinal direction of the light guiding body, and a light outputting part for irradiating the guided light along with the longitudinal direction. A wedge shaped projection and a projection with planar leading end are formed at mutually facing positions for controlling light running from the light guide towards the light outputting part between the light guide and the light outputting part, reduction of light volume irradiated from the light outputting part is controlled with the projections, and illumination distribution are decreased in the longitudinal direction of the light guiding body. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line illumination device used in an image reading apparatus such as an image scanner, a facsimile machine, or a copying machine, and more particularly to a line illumination used in an image sensor unit that irradiates a reading surface of a document and reads reflected light. The present invention relates to an apparatus and an image reading apparatus using the same.

  2. Description of the Related Art Conventionally, there are various types of image sensors used in image reading apparatuses such as image scanners, facsimiles, and copiers, such as reduction types and contact types. Among them, the contact image sensor (hereinafter abbreviated as CIS) includes an illumination device, a unity magnification optical device, a line sensor, and the like. Such CIS generally has a feature that the optical path length is shorter than that of an image sensor using a reduction optical system, and thus a device including this image sensor can be easily miniaturized. As described above, since CIS can be easily incorporated into a device, it has been widely used in a thin flat bed type image reading apparatus or the like in place of a reduction optical system. Such a line illuminating device used for CIS is required to illuminate a document surface with a required illuminance or higher so that reflected light from the document reaches the line sensor with sufficient intensity.

  FIG. 4 is a cross-sectional view of a conventional contact image sensor, and shows a case where the number of the light guides 42 is one. This contact image sensor has a light source for irradiating an original, receives reflected light from the original 49 through a lens 44 by a light receiving portion formed by a photoelectric conversion element (CCD), and converts it into an electrical signal.

  In the figure, reference numeral 43 denotes a frame that supports the constituent members, and 44 denotes a lens array that forms an optical image of a document 49 on a line sensor 45. Reference numeral 45 denotes a line sensor arranged in a line having a plurality of light receiving portions that photoelectrically convert an optical image of the document 49 into an electric signal. Reference numeral 46 denotes a sensor substrate on which the line sensor 45 is mounted. Each of 41r, 41g, and 41b is a light source having an LED for illuminating the document 49, and is disposed on one end face of the light guide 42 that extends in the longitudinal direction. The light source unit 41 includes a light guide 42 designed to take in light emitted from the LEDs 41r, 41g, and 41b and to make the amount of illumination light substantially uniform over the length of one line of the line sensor 45. . Reference numeral 47 denotes a connector for connecting a sensor signal to an external device, and reference numeral 48 denotes a transparent glass document support table for supporting the document 49.

  The light emitted from the LED disposed on the end face of the light guide 42 is guided to the acrylic light guide 42 and is emitted to the outside from the emission surface (light emitting portion) while reflecting the inside in a complicated manner. The document 49 is illuminated. For the purpose of assisting reflection in the light guide body, titanium oxide powder or aluminum powder is disposed on the reflection part or the terminal part (opposite side of the light incident surface) of the light guide body 42 by means such as printing. preferable.

As these line-shaped illuminating devices, a line-shaped illuminating device in which a light emitting element is provided at one end (light incident portion) of an acrylic rod-shaped transparent body (light guide) is used. (For details, see Patent Document 1, Patent Document 2 and Patent Document 3)
The line-shaped illuminating devices described in these publications aim to reduce costs by arranging LEDs that are light-emitting elements only at one end of a rod-like transparent body (light guide). Furthermore, the shape of the light guide is devised so that uniform illuminance can be obtained along the longitudinal direction of the light guide, and from the light incident surface of the light guide on which light from the LED is incident toward the terminal portion. The illuminance is as uniform as possible.
Japanese Patent Registration Publication No. 2693098 JP-A-8-163320 Japanese Patent Laid-Open No. 10-241432

  However, the above conventional example has the following problems.

  First, FIG. 5A and FIG. 5B show an example of a cross-sectional shape of a conventional line illumination device described in Patent Document 3, and the problems will be described.

  The arrow in the figure indicates the direction of the light beam. In FIG. 5A, a wedge-shaped protrusion indicated by 500 is provided between a light guide portion 501 in which light from a light incident surface enters in a substantially vertical direction of the drawing and a light exit portion 502 from which the light exits. . In this configuration, there is a relatively large amount of light 510 that returns from the light exit unit 502 to the light guide unit 501. Further, the light 511 traveling from the light guide unit 501 to the light output unit 502 is also emitted in a direction different from the predetermined direction. For this reason, these lights do not become effective illumination light. As a result, there is a problem that the illumination light quantity cannot be increased due to insufficient illumination light quantity.

  In FIG. 5B, two wedge-shaped protrusions are provided as indicated by 500 and 503. Similarly in these shapes, the reflected light 512 from the bottom surface 521 on the light guide unit 501 side enters the light output unit 502, and the light is emitted in a direction that does not contribute to illumination of the document. On the other hand, like the reflected light from the bottom surface 522 on the light exiting portion 502 side, the light returns from the light exiting portion 502 to the light guiding portion 501, and the light is not emitted and the illumination light amount of the document is reduced. was there.

  An object of the present invention is to solve such conventional problems.

  A feature of the present invention is that, in a contact image sensor unit, line illumination that increases the illuminance of illumination light emitted from a linear illumination device and makes the illuminance distribution along the longitudinal direction of the light guide more uniform. To provide an apparatus.

  Another feature of the present invention is to provide a line illuminating device that improves the rising characteristics of the illuminance of the illumination light and makes the effective reading length of the light guide longer.

In order to achieve the above object, a line illumination device according to one embodiment of the present invention has the following configuration. That is,
The present invention comprises a light source;
A light guide unit that is made of a transparent medium and receives light from the light source from a light incident surface and guides the light along the longitudinal direction; and the light guided to the light guide unit in the longitudinal direction. A light guide having a light exit portion having an exit surface for exiting in a line shape;
In order to control the amount of light that travels from the light guide to the light exit, first and first disposed at opposite positions along the longitudinal direction of the light guide between the light guide and the light exit. And the first protrusion has a wedge shape and the height changes according to the distance from the light incident surface, and the light guide section on the side wall surface of the light guide section of the second protrusion The linear illumination device according to claim 1, wherein a first angle formed with respect to the side bottom surface is larger than a second angle formed by the light output portion wall surface of the second protrusion with respect to the light output portion side bottom surface.

  The light guide further includes a first region in which a height of the second protrusion continuously increases along the longitudinal direction from the light incident surface, and the first region, A second region in which the height of the second protrusion is substantially constant.

  Further, the light guide has a first region in which the height of the second protrusion continuously increases along the longitudinal direction from the light incident surface, and the second region following the first region. A second region in which the height of the protrusion is substantially constant, and a second region in which the height of the second protrusion continuously decreases toward the end portion along the longitudinal direction following the second region. 3 regions.

  According to the present invention, not only the illuminance of the linear illumination device increases, but also the illuminance distribution becomes more uniform. In addition, since the illuminance distribution of the illumination light emitted in the vicinity of the light incident part of the light guide is uniform, the effective reading length of the light guide can be made longer, unnecessary space is reduced, and product mounting is also downsized. There are advantages you can do. In addition, even if the arrangement position of the LED with respect to the light guide is shifted, it is difficult to influence the illuminance distribution, so that the height position adjusting process in the LED mounting process can be made relatively simple.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the present invention according to the claims, and all combinations of features described in the present embodiments are essential to the solution means of the present invention. Not exclusively.

  The light guide of the line illumination device according to the present embodiment has basically the same shape as the light guide shown in FIG. 4, but a wedge-shaped protrusion coming between the light guide and the light exit. It is characterized by having a rectangular projection structure instead of. As described above, this embodiment is characterized in that, in addition to the conventional line illumination device, a new structure for controlling the amount of emitted light is added in the vicinity of the light guide unit and / or in the vicinity of the light output unit.

[Embodiment 1]
An example of a line illumination device according to Embodiment 1 of the present invention is shown in FIG.

  FIG. 1A shows a cross-sectional view at a substantially central portion in the longitudinal direction of the light guide 100 of the line illumination device according to the first embodiment. The light guide 100 can be roughly divided into a light guide part 101 and a light exit part 102 along the longitudinal direction. An LED 120 serving as a light source is disposed in the vicinity of an end face (hereinafter referred to as a light incident surface 110 (FIG. 1B)) on at least one side of the light guide 100. The light guide unit 101 receives light emitted from the LEDs 120 arranged near the outside of the light incident surface 110, transmits the light in the longitudinal direction of the light guide 100, and develops the light toward the light output unit 102. It has a function to do. The light exit unit 102 receives light from the light guide unit 101 and emits light in a predetermined direction from a light exit surface provided in a part of the light exit unit 102. As a result, the read target portion of the document is illuminated in a line.

  In the light guide 100 shown in FIG. 1A, a protrusion 103 having a rectangular structure having a certain height is formed at the boundary between the light guide section 101 and the light output section 102, and a wedge-shaped protrusion is formed at a position facing the protrusion 103. A protrusion 104 (hereinafter abbreviated as a wedge portion) is provided. The projection 103 and the wedge portion 104 serve as a light quantity adjustment valve, which is common to the conventional idea. However, in the first embodiment, the transmission of light between the light guide unit 101 and the light output unit 102 is more effectively controlled by making the cross-sectional shape of the protrusion 103 rectangular. Regarding the wedge portion 104, the amount of light entering the light exit portion 102 is controlled by changing the height of the wedge portion 104 in accordance with the distance from the light source along the longitudinal direction of the light guide 100. Specifically, the height of the wedge portion 104 is maximized near the approximate center in the longitudinal direction of the light guide 100, and the height is decreased at the light incident surface and the end portion. The protrusion 103 has a smaller angle (preferably an acute angle) with respect to the lower surface on the light output unit 102 side than the angle with respect to the bottom surface on the light guide unit 101 side.

  FIG. 1B is a schematic perspective view showing the entire light guide 100.

  The light guide 100 is formed of a transparent medium, and the projections 103 are formed in the same shape from the light incident surface 110 toward the terminal portion. The wedge portion 104 is low near both ends and highest at the center. Is formed.

  FIG. 2 is a cross-sectional view of the light guide 100 for explaining the role of the protrusion 103.

  In FIG. 2, the light exit surface side of the protrusion 103 has a wall surface having an angle in the vertical direction as compared with the conventional example shown in FIGS. 5A and 5B. Thus, the light 201 traveling directly from the light guide unit 101 to the light output unit 102 at a low angle is blocked, and the light 202 returning from the light output unit 102 to the light guide unit 101 is blocked. Thus, the first bottom surface 210 belonging to the light guide unit 101 and the second bottom surface 211 belonging to the light output unit 102 reduce the amount of light once entering the light output unit 102 back to the light guide unit 101. Since the light that enters the light output unit 102 from the light guide unit 101 is also used efficiently, the illuminance on the document can be increased compared to the conventional example.

  FIG. 3 is a diagram illustrating the illuminance distribution in the longitudinal direction of the lighting apparatus according to the present embodiment.

  In FIG. 3, the LED as the light source is arranged on the light incident surface side, that is, on the left side in FIG. 3, and the vertical axis indicates relative illumination at the illumination position of the document along the longitudinal direction of the light guide 100. It shows the amount of light. The horizontal axis represents the length from the light incident surface 110 (unit: mm).

  In FIG. 3, a line indicated by 300 indicates the illuminance characteristics in the lighting apparatus according to the present embodiment, and a line indicated by 301 indicates the illuminance characteristics by the conventional lighting apparatus having a cross section shown in FIG. 5B. . In the conventional illuminating device, the illuminance increases at a position of about 15 mm from the light incident surface 110, and then shows the maximum illuminance and gradually attenuates toward the end portion. This is presumably because a part of the light emitted from the light source (LED) directly enters the light exit part 102 in the vicinity of the light incident surface 110 and increases the amount of light near the light incident surface.

  On the other hand, in the illuminating device which concerns on Embodiment 1 of this invention, the tendency is relieved and it turns out that substantially uniform illumination intensity is obtained over the longitudinal direction of the light guide 100. FIG.

[Embodiment 2]
Here, when observing FIG. 3 which is the illuminance characteristic of the lighting apparatus according to Embodiment 1 in more detail, there is a region where the illuminance is low in the vicinity of about 15 mm from the light incident surface 110, and the same is also observed in the vicinity of about 10 mm from the end portion. It can be seen that there is a region where the illuminance falls more. This is considered to be because the direct light from the light source 120 enters almost the center of the light guide 100, so that the light diffuses in the vicinity of the light incident surface 110 and the light reaching the light exit portion 102 decreases.

  On the other hand, in the conventional lighting device, the peak of illuminance is obtained in the range of 20 to 50 mm from the light incident surface. This is considered to be caused by the addition of light that reaches the light exit unit 502 directly from the light source. On the other hand, since the illuminance is low near the light incident surface of the illuminating device, the original cannot be read near the light incident surface. Therefore, this part is a useless part of the lighting device. Similarly, there is also a portion where the illuminance is reduced in the range of several millimeters from the end portion at the end portion on the opposite side of the light incident surface. Therefore, it is required to shorten the length of the portion where the illuminance is lowered to reduce the useless portion.

  Such illuminance characteristics are slightly different for each color. Currently, many CISs use LEDs of three colors, red, green and blue. As shown in FIG. 4, these are arranged in the horizontal direction in the vicinity of the light incident surface of the light guide. For this reason, depending on the position where the LED is disposed, the LED farther from the light-emitting portion tends to deteriorate the illuminance rising characteristic. As a result, not only the illuminance uniformity in the vicinity of the light incident portion but also the chromaticity characteristics at the light exit portion have been degraded.

  In addition, since the portion where the illuminance decreases in this way is not used for reading the original, both ends of the CIS cannot be used and are wasted. Therefore, there has been a demand for the entire area to be an effective area while keeping the size of the lighting device small.

  Therefore, in the second embodiment, in order to improve the decrease in illuminance in the vicinity of the light incident portion, the height of the protrusion 103 is lowered in the very vicinity of the light incident surface to directly block the direct light from the light source 120. A part of the light is taken into the light emitting unit 102 and used as illumination light. Thus, it is characterized in that a region with low illuminance near the light incident surface is reduced.

  FIG. 6 is a schematic perspective view of a light guide 100a according to Embodiment 2 of the present invention.

  The light guide 100a is formed by molding an acrylic material into the shape shown in FIG. The light guide 100a has a long and narrow shape, and includes a light guide unit 101 that guides light from the light source 120 in the longitudinal direction and a light output unit 102 that emits illumination light that illuminates the document in a line shape. Is the same as in the first embodiment. As in the first embodiment, the wedge portion 104 and the protrusion 103 shown in FIG. 6 are formed at the position where the light guide portion 101 and the light output portion 102 are separated.

  The shape of the protrusion 103 includes a first protrusion region 601 whose height gradually increases until the distance from the light incident surface 110 is about 5.5 mm along the longitudinal direction of the light guide 100a. After that, it has the 2nd projection area | region 602 which is a shape which reaches a termination | terminus part by fixed height. This feature is that in the region where the distance from the light incident surface 110 is about 5.5 mm, the height of the protrusion 103 and the height of the wedge portion 104 are terminated from a state where there is substantially no height (height = 0). When the height is gradually increased in the direction of the portion and the first protrusion area 601 enters the second protrusion area 602, the height of the protrusion 103 becomes constant at the height of the first embodiment described above, for example. is there. As a result, more light, including direct light from the light source 120 and light from the bottom surface of the light guide unit 100 a, reaches the light output unit 102 from the light guide unit 101. In this way, a decrease in illuminance near the light incident surface 110 is compensated.

  In the vicinity of the light incident surface 110, there is light that travels directly from the LED 120 to the light exit portion 102, and conventionally, this direct light has been blocked by forming protrusions or the like so as not to be used as much as possible. On the other hand, in the second embodiment, on the contrary, by using the direct light from the light source 120, the illuminance in the vicinity of the light incident surface 110 was successfully increased.

  On the contrary, in the portion where the distance from the light incident surface 110 is long, the height of the protrusion 103 is increased, and the light amount is adjusted by changing the height of the wedge portion 104 according to the distance. As a result, the amount of light reaching the light exiting portion 102 is adjusted to make the illuminance in the longitudinal direction of the light guide 100a uniform.

  The result that the illuminance in the vicinity of the light incident surface 110 is improved by the light guide body 100a of the second embodiment will be described with reference to FIG.

  FIG. 9 is a diagram showing the rising characteristics of illuminance in the vicinity of the light incident surface of the illumination devices according to Embodiments 1 and 2 of the present invention. In the figure, 900 indicates the result according to the first embodiment, and 901 indicates the result according to the second embodiment.

  In FIG. 9, the illuminance in the vicinity of the light incident surface is shown as a relative value, but in the second embodiment, the illuminance rises better when the distance from the light incident surface is about 4 mm than in the first embodiment. Recognize. As a result, the effective length of the light guide that can effectively irradiate the document is increased, and the length of the light guide corresponding to a document having a certain width can be relatively shortened. .

  Further, it has been found that the shape of the light guide body 100a of the second embodiment further has the following new effects.

  FIG. 10 is a diagram showing the illuminance distribution when the LED mounting positions are different in the lighting apparatus according to Embodiment 1 of the present invention.

  In the light guide 100 shown in Embodiment 1, when the arrangement position of the LED 120 arranged on the light incident surface 110 side is shifted in the vertical direction, the illuminance distribution characteristics are different in the longitudinal direction of the light guide 100. Yes. In particular, in the region close to the light incident surface 110, it has been found that the illuminance change is large even if the mounting position of the LED 120 is slightly different. Therefore, in the illuminating device of Embodiment 1, it is necessary to carefully adjust the mounting height position of the LED 120 in the manufacturing process, which is extremely complicated in the manufacturing process.

  FIG. 11 is a diagram showing the illuminance distribution when the LED mounting positions are different in the illumination device according to Embodiment 2 of the present invention.

  FIG. 11 shows the illuminance distribution characteristic in the longitudinal direction when the LED mounting position is changed. Thus, it can be seen that the illuminance distribution characteristics do not change much even if the LED mounting positions are different. Therefore, in the manufacturing process, the alignment of the LED is simplified, the variation in the illuminance distribution of the product is reduced, and the manufacturing process time can be shortened.

[Embodiment 3]
In the third embodiment, in addition to the vicinity of the light incident surface 110, the height of the protrusion 103 in the vicinity of the terminal portion is changed stepwise. The details are shown in FIG.

  FIG. 7 is a schematic perspective view of the light guide 100b of the lighting apparatus according to Embodiment 3 of the present invention.

  In the third embodiment, the first protrusion region 701 in which the height of the protrusion gradually increases from the light incident surface 110 as shown in FIG. 7 along the longitudinal direction of the light guide 100b. In addition to the second groove region 702 in which the protrusion 103 having a constant height is formed, a third groove region 703 in which the protrusion 103 gradually decreases from about 6 mm from the end portion is provided. It is. The shape of the wedge portion 104 is the same as that in the first and second embodiments.

  In addition, a reflection member made of aluminum or the like is disposed at the end portion of the light guide 100b to increase the reflection efficiency of light from the light source 120. By doing so, the light source is arranged at the end portion, and the tendency for the illuminance to decrease near the end portion is alleviated. Therefore, it is possible to reduce the portion where the illuminance decreases in the vicinity of the terminal portion. As a result, the effective length of the light guide that gives a relatively effective illuminance is increased, and the area that cannot be used due to the low illuminance can be shortened. As a result, the length of the illumination device that illuminates a document having a certain length can be shortened, and the width of the image reading device can be shortened accordingly.

  In the first and second embodiments described above, a reflecting member made of aluminum or the like may be disposed at the end of the light guide 100b.

[Embodiment 4]
A flat bed type image scanner using the illumination device according to the first to third embodiments will be described.

  FIG. 8 is a schematic perspective view of an image reading apparatus which is an application example of the image sensor according to the embodiment of the present invention. Here, an example of a flat bed type image reading apparatus using a contact type image sensor is shown.

  In FIG. 8, reference numeral 81 denotes a CIS provided with the lighting device of the present embodiment. 82 is a glass plate as a document support, 83 is a wire for operating the CIS, 84 is a drive motor for moving the wire 83 to sweep the CIS, and 85 is a pressure plate for the document.

  By driving the drive motor 84 and mechanically moving the wire 83, the CIS 81 can move in the reading direction (scanning direction) and read the image information of the document. The CIS is configured as a sensor unit in which an illuminating unit is integrated, and reflected light from an illuminated original is condensed on a photoelectric conversion element by a lens array (not shown) in the CIS, and is used as image information for each line. Is output. In this way, sheet-like image information can be read and output.

  In the image scanner equipped with the CIS unit according to the present embodiment, the length of the illumination device can be further shortened, so that the width of the image scanner can be shortened and the size of the image reading device can be further reduced. it can.

  As described above, according to the present embodiment, not only the illuminance of the line illumination device can be increased, but also the illuminance distribution becomes more uniform.

  In addition, since the illuminance distribution of the illumination light emitted in the vicinity of the light incident portion of the light guide becomes uniform, the effective reading length of the light guide can be made longer. As a result, unnecessary space is reduced and there is an advantage that the product can be miniaturized.

  Moreover, according to this Embodiment, since the influence with respect to illumination intensity distribution can be made small even if the arrangement position of LED with respect to a light guide has shifted | deviated, the attachment position adjustment in the attachment process of LED can be made comparatively simple.

  The present invention is not limited to the embodiment described above, and various changes and modifications can be made without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should be specified by the following claims.

It is sectional drawing of the linear illuminating device which concerns on Embodiment 1 of this invention. It is a perspective view of the line-shaped illuminating device which concerns on Embodiment 1 of this invention. It is a figure which shows the optical effect at the time of using the linear illuminating device which concerns on Embodiment 1. FIG. It is a figure which shows the illumination intensity distribution of the longitudinal direction of the linear illuminating device by Embodiment 1 of this invention. It is a structure sectional view of the conventional contact type image sensor. It is sectional drawing of the conventional illuminating device with a wedge part. It is a figure which shows the motion of the light which is unpreferable of the conventional illuminating device with a wedge part. It is a perspective view which shows the structure of the illuminating device which concerns on Embodiment 2 of this invention. It is a perspective view which shows the structure of the illuminating device which concerns on Embodiment 3 of this invention. It is a figure which shows an example of the flatbed type image reading apparatus using the illuminating device which concerns on embodiment of this invention. It is a figure which shows the rising characteristic of the illumination intensity in the light-incidence surface vicinity of the illuminating device which concerns on Embodiment 1, 2 of this invention. It is a figure which shows illuminance distribution when the attachment position of LED differs in the illuminating device which concerns on Embodiment 1 of this invention. It is a figure which shows illuminance distribution when the attachment position of LED differs in the illuminating device which concerns on Embodiment 2 of this invention.

Claims (9)

A light source;
A light guide unit that is made of a transparent medium and receives light from the light source from a light incident surface and guides the light along the longitudinal direction; and the light guided to the light guide unit in the longitudinal direction. A light guide having a light exit portion having an exit surface for exiting in a line shape;
In order to control the amount of light that travels from the light guide to the light exit, first and first disposed at opposite positions along the longitudinal direction of the light guide between the light guide and the light exit. 2 protrusions,
The first protrusion has a wedge shape, and the height thereof changes according to the distance from the light incident surface, and the first protrusion is formed with respect to the light guide portion side bottom surface of the light guide portion side wall surface of the second protrusion. The line illumination device characterized in that an angle is larger than a second angle formed by the light exit wall surface of the second protrusion with respect to the light exit bottom surface.   The light guide further includes a first region in which a height of the second protrusion continuously increases along the longitudinal direction from the light incident surface, and the second region following the first region. The line-shaped illumination device according to claim 1, further comprising: a second region in which a height of the protrusion of the first projection is substantially constant.   The light guide further includes a first region in which a height of the second protrusion continuously increases along the longitudinal direction from the light incident surface, and the second region following the first region. A second region in which the height of the protrusion is substantially constant, and a third region in which the height of the second protrusion continuously decreases toward the end portion along the longitudinal direction following the second region. The line illumination device according to claim 1, further comprising:   The line-shaped illumination device according to claim 3, wherein the light guide has at least one of the first, second, and third regions.   5. The cross-sectional shape of the second protrusion is a wedge shape, and the height of the second protrusion changes continuously along the longitudinal direction of the light guide. Item 2. The line illumination device according to item 1.   6. The light guide body according to claim 1, further comprising: a reflecting member that reflects light at a terminal portion opposite to the light incident surface. Line lighting device.   The line-shaped illumination device according to claim 1, wherein the light source is an LED, and the light source is disposed in contact with or close to the light incident surface.   The line illumination device according to any one of claims 1 to 7, wherein the first angle is an obtuse angle and the second angle is an acute angle. A line illumination device according to any one of claims 1 to 8,
A line-shaped image forming means for forming an image of reflected light from the original;
A line sensor comprising a plurality of pixels for converting the reflected light into an electrical signal;
An image reading apparatus comprising:

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