JPH07262295A - Condensing device - Google Patents

Abstract

PURPOSE:To make much of irregularly reflected light incident on a light transmission plate by providing the light transmission plate with a lens function and a deflection means for propagating the reflected light from a reading object to a photoelectric conversion element. CONSTITUTION:On a light transmission plate 1, a condensing lens 13 condensing the reflected light from an original surface 2 on this light transmission plate 1 and a means 11 deflecting the condensed reflected light in the direction of a photoelectric conversion element 10 installed at the both ends are formed. In the lens 13, the light 18 illuminated vertically to the original surface 2 has a shape that the part of reflected light 19 scattered on the original surface 2 is condensed to this tooth shape projecting and recessing parts 11 by the section formed on the surface opposed to the lens 13. When light is propagated to the photoelectric conversion elements 10 of the both ends by doing this, the width of a blaze 1 to be a hindrance becomes possible to be reduced. Because the approaching to the original surface of the condensing lens 13 on the light transmission plate 1 becomes possible, the reflected light 19 of 50 deg. to 60 deg. width can be condensed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reading device for illuminating a linear region with illumination light while scanning, optically reading image information in the illuminated region, and converting and inputting into an electric signal. Concerning optical devices, it mainly focuses on bar code readers and other image input devices such as various laser scan type document reading devices and image scanners, and laser surface inspection devices that inspect fine scratches on the surface of wafers and glass substrates. It is used for devices.

[0002]

2. Description of the Related Art In recent years, the use of bar code symbols as computer input means has become particularly popular.
It has come to be widely applied in fields such as the field of logistics. As described above, the means for optically reading information by scanning the linear region with the illumination light is not limited to the barcode, but is also used in many other technical fields as described above, and many of the devices are also used. Has already been disclosed. For example, 109 of the technical magazine O plus E 1993 October issue.
On page 113, a report entitled "Optical system of barcode reader" is shown, and it can be said that a rotary polygon mirror or a hologram scanner is put into practical use as a scanner as a basic configuration of the optical system. There is.

FIG. 21 shows an example of the structure of an apparatus for scanning information to be read by illuminating light in the conventional optical system as described above. This structure scans the illumination light 18 such as laser light emitted from the light source 17 and emitted through the lens 16 as means for guiding the reflected light 19 from the reading target 2 such as the document surface to the photoelectric conversion element 10. Only the reflected light 19 returning to the rotating polygon mirror 15 used as a means for causing it is guided to the photoelectric conversion element 10. In order to guide only the reflected light 19 to the photoelectric conversion element 10, the illumination light 18 and the reflected light 19 from the reading object 2 are separated from the illumination light 18 by means of, for example, a perforated mirror 14 or the like, and photoelectrically converted. Condensing lens 13 installed immediately before the element 10
By a, only the reflected light 19 from the reading target 2 is condensed on the photoelectric conversion element 10.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As exemplified above,
As a means for guiding the reflected light from the reading object to one photoelectric conversion element in the conventional illumination light scanning type reading device, a means for scanning the illumination light, for example, a reflected light from the reading object using a rotating polyhedral mirror Is returned to the same optical path as the illumination light, and only the reflected light needs to be guided to the photoelectric conversion element by using a means for separating the illumination light and the reflected light there. In addition, the means for separating the illumination light and the reflected light from the reading object must be installed after the rotating polyhedron mirror where the reflected light from anywhere in the longitudinal direction of the reading object has the same optical path, so that the reflection light A condenser lens for condensing only light on the photoelectric conversion element must be installed behind the separating means.

Therefore, the distance between the object to be read and the condenser lens for condensing the reflected light cannot be shortened, so that the amount of light entering the condenser lens out of the amount of light reflected by the object to be read is very large. There were few. Furthermore, since the condenser lens and the photoelectric conversion element are individually installed, optical alignment is required. Therefore, an object of the present invention is to efficiently propagate the reflected light from the object to be read and redirect it to the photoelectric conversion element, and also to suppress the occurrence of reflection loss and propagation loss at that time. An object of the present invention is to provide a condensing device that enables the above. Another object of the present invention is to provide a light-collecting device which can obtain a uniform output regardless of the position in the longitudinal direction, can be easily assembled and can be miniaturized.

[0006]

The present invention has been made to solve the above problems, and the first of its gist is to illuminate an object to be read by an image reading device with illumination light.
A light condensing device for condensing reflected light from the reading target on a photoelectric conversion element by a light guide plate, wherein the light guiding plate has a lens function for condensing the reflected light from the reading target and has a cross section of The condensing device is provided with a saw-toothed concavo-convex, and includes a deflecting unit for propagating the reflected light from the reading target to the photoelectric conversion element.

A second aspect of the present invention is a light condensing device in which illumination light scans a reading object of an image reading device, and reflected light from the reading object is condensed on a photoelectric conversion element by a light guide plate. In the light guide plate, one side surface is formed into a lens shape having a function of condensing reflected light from the reading target, and a cross section is formed on a side surface facing the side surface on which the lens is formed. It is formed into sawtooth-shaped irregularities,
The condensing device constitutes a deflecting means for focusing the reflected light from the reading object on the unevenness and propagating it to the photoelectric conversion element.

Further, in the above structure, the width of the concave and convex portions having a saw-tooth cross section in the longitudinal direction of the light guide plate is narrower than the width of the lens in the longitudinal direction of the light guide plate. A reflection film is formed on the surface of the unevenness having a saw-tooth cross section, or the width of the unevenness of the light guide plate in the saw-tooth shape having a saw-like cross section is The light guide plate is formed to change so that it is wide near the center in the longitudinal direction of the light guide plate and narrows toward both ends. Furthermore, the light guide plate is provided with the lens, the diverting means, and the photoelectric conversion element integrally provided. To be
Are all valid.

[0009]

Since the light condensing device having the above-described structure can be brought very close to the reading target illumination surface, a large amount of light scattered and reflected by the reading target surface can be made incident on the light guide plate. Further, this light is propagated to the photoelectric conversion element by being collected by means for changing the direction of the photoelectric conversion element provided on at least one side surface. For the propagation to the photoelectric conversion element, since the surface other than the portion of the saw-toothed concave and convex portion for changing the direction of light is used and the light is propagated by total reflection, it is necessary to reduce the width of the changing means.

For the above reason, in the lens, the higher the efficiency of condensing light on the narrow concave-convex portion which is the deflecting means, the greater the amount of propagation to the photoelectric conversion element. In addition, since the surface other than the unevenness utilizes total reflection, the more light enters the photoelectric conversion element as the reflectance of the unevenness is increased by adding a reflective film only to the unevenness. Furthermore, by adjusting the width of the unevenness, it is effective to obtain a uniform output regardless of the position in the longitudinal direction. Also, by forming the lens part and the uneven part on the same light guide plate and installing the photoelectric conversion element on the side surface of the light guide plate and integrating them, there is no need for optical alignment between the condenser lens and the photoelectric conversion element. Becomes

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the accompanying drawings. First, a document reading unit using the light guide plate used in the present invention will be described. FIG. 1 is a perspective view of an illumination scanning type document reading unit in the light collecting device of the present invention. That is, in this embodiment, the document surface corresponds to the reading target. FIG. 1 shows an installation example of the light guide plate 1 used in the present invention. The light guide plate fixing jigs 3, 4 for fixing the light guide plate 1 are formed at the same time when the side wall 6 and the jig 8 of the unit are molded as shown in the perspective view of FIG. Has projections 9a and 9b for engaging the light guide plate fixing jigs 3 and 4 at the end of the light guide plate 1 as shown in the enlarged view of FIG.

Next, as shown in the sectional view of the mounting portion of FIG. 4, the light guide plate 1 is fitted in the light guide plate fixing jigs 3 and 4, and the convex portions 9a and 9b formed at both ends of the light guide plate 1 are attached. The jig 5 is fixed to the light guide plate fixing jigs 4 and 3, respectively, and the jig 5 is fixed by screws 7a and 7b so as to press the light guide plate 1. The light guide plate 1 has a structure in which the reflected light from the original surface 2 to be read propagates by utilizing the total reflection, and therefore the light guide plate fixing jig 3 is used in order not to reduce the effect. , 4, 5 are fixed only at both ends of the light guide plate 1. Although the photoelectric conversion element is omitted in FIG. 1, the photoelectric conversion element 10 is actually installed at the end of the light guide plate 1 in the longitudinal direction as shown in the perspective view of FIG.

In this embodiment, the illumination light 18 is radiated perpendicularly to the scanning line 20 on the original surface 2, and the light guide plate 1 is 30 ° to 60 ° by the fixing jigs 3, 4 and 5. The structure is set so as to be tilted so that the specularly reflected light on the document surface 2 returns in the vertical direction. However, conversely, the same effect can be obtained even when the illumination light is irradiated at an angle of 30 ° to 60 ° with respect to the document surface 2 and the light guide plate is installed perpendicularly to the document surface. Will be described only.

Since the light guide plate 1 has a structure for propagating the reflected light from the document surface 2 into the light guide plate 1, it is optimal to use a material having high transmittance and easily formed. Therefore, a highly transparent resin such as acrylic resin or polycarbonate is used. Since these resins can be molded by a mold, a condenser lens 13 that condenses the reflected light from the original surface 2 on the light guide plate 1 and the condensed reflected light are installed at both ends. Photoelectric conversion element 1
The means 11 for changing the direction to 0 can be formed at the same time, and mass production is easily possible. This light guide plate 1
The diverting means 11 in is formed on the surface facing the surface on which the condenser lens 13 is formed, as shown in the perspective view of FIG.

As shown in the sectional view of FIG. 7, the lens 13 receives the light 18 which is illuminated perpendicularly to the original surface 2.
The cross section formed on the surface facing the lens 13 has a shape such that a part of the reflected light 19 scattered on the document surface 2 is condensed into sawtooth-shaped irregularities (hereinafter referred to as blaze) 11. ing. By doing so, it becomes possible to reduce the width of the blaze 11 which is an obstacle when light propagates to the photoelectric conversion elements 10 at both ends. Further, unlike the conventional condensing lens 13a (see FIG. 21), the condensing lens 13 on the light guide plate 1 used in the present invention can be brought closer to the document surface 2, so that the conventional document surface 2 Of the scattered reflected light of 1), only the light having a width of several degrees can be collected, but when the light guide plate 1 used in the present invention is used, the reflected light 19 having a width of 50 ° to 60 ° can be collected. it can. Therefore, the amount of light entering the photoelectric conversion element 10 increases.

Blaze 1 formed on the light guide plate 1
1 is not formed on the entire facing surface of the condenser lens 13 for the above-mentioned reason, but is formed only on the central portion as shown in the shape explanatory view of FIG. Further, regarding the portion of the blaze 11, a metal film having a high reflectance, such as aluminum or the like, is used so as to minimize reflection loss generated when the reflected light 19 from the document surface 2 is redirected toward the photoelectric conversion element 10. A metal such as silver or gold is formed by sputtering or vapor deposition. In addition, since total reflection is used for the blaze-free portion 11d, it is possible to prevent a decrease in the amount of light propagating to the photoelectric conversion element 10 by not attaching the above-described metal film or the like.

As for the shape of the blaze 11, when the photoelectric conversion elements 10 are installed on both sides as shown in the sectional view of FIG. 9 and the total thereof is used as the output of the photoelectric conversion element 10,
It is desirable that the reflected light 19 condensed by the lens 13 be equally distributed to the left and right (α = β).
If the pitch p is set to about 1 mm, the angle setting will be 4
It is considered that an appropriate value is about 5 ° to 65 °, but since the amount of light entering the photoelectric conversion element 10 is maximum at about 110 ° at the apex angle of the blaze, α (= β) is about 35. It is preferable to set it so that the angle becomes °. Since this angle setting changes when the pitch p of the blaze 11 changes, the angle that matches the pitch may be determined and adopted by experiments or simulations. Also, regarding the cross-sectional shape of the blaze,
Even if the shape shown in the shape examples of FIGS. 10A and 10B is obtained, the same effect as the above-described shape can be obtained.

The light guide plate 1 has a structure in which the reflected light 19 from the document surface 2 condensed by the condenser lens 13 hits the blaze 11 and propagates to the photoelectric conversion element 10, but at the end of the document surface 2. In the reflected light 19 of, the light that directly enters the photoelectric conversion element 10 (light that directly enters the photoelectric conversion element 10 without hitting the blaze portion 11) increases. Therefore, as shown in the shape explanatory view of FIG. 8, the width of the blaze 11 is changed in the longitudinal direction such that the width is widened in the vicinity of the center in the longitudinal direction and is narrowed in the vicinity of both ends. Accordingly, in the vicinity of the center, the light entering the photoelectric conversion element 10 is increased by the reflected light by the blaze 11, and in the vicinity of both ends, the light entering the photoelectric conversion element 10 is increased. The amount is adjusted so that a uniform output can be obtained regardless of the position in the longitudinal direction.

Further, conventionally, as shown in FIG. 21, a means 15 for separating illumination light and reflected light, a condenser lens 13a, and a photoelectric conversion element 10 have to be individually arranged, and each of them has an optical element. Alignment was needed. However, in the light guide plate 1, since the condenser lens 13, the blaze 11 which is the changing means, and the photoelectric conversion element 10 are integrated, no individual optical alignment is required, and only the light guide plate 1 is positioned. It will be good if they match. Therefore, it is very easy to assemble.

Next, the embodiment shown in FIG. 11 is a sectional explanatory view of a laser scanning type surface inspection apparatus using the light guide plate 1 used in the present invention. In this case, a scratch on the inspection target corresponds to this as the reading target. If there is no scratch on the surface of the wafer or glass substrate to be inspected 27, the incident laser beam 18 returns to vertical again as shown in FIG. 11A, so that almost no scattered light is incident on the light guide plate 1. However, the surface of the inspection target 27 has fine scratches 28.
11B, the incident laser light 18 is scattered on the surface, and scattered light 19 enters the light guide plate 1 and is guided to the photoelectric conversion element via the blaze 11. Therefore,
The position of the scratch 28 on the surface of the inspection object 27 can be known from the scanning time of the laser light and the incident intensity at the photoelectric conversion element.

Next, FIGS. 12 and 13 are cross-sectional views for explaining how the reflected light 19 propagates in some examples of the light guide plate. First, in the example of one aspect shown in FIG. The photoelectric conversion element 10 is installed on only one side of the light guide plate 1b. Therefore, the photoelectric conversion element 1
In order to prevent the reflected light from the original from propagating toward the surface 12 having no 0, as shown in FIG. 12, α> β is set, and the surface on which the blaze 11b is formed is further inclined so that the side surface 1
2 is formed with a metal film having a high reflectance. In addition, even in the shape of the light guide plate 1c like the other embodiment shown in FIG.
By setting the angle of the blaze 11c to α = 90 ° and setting β to an appropriate angle, the same effect as that of the light guide plate 1b can be obtained.

By installing the photoelectric conversion element 10 on only one side of the light guide plate 1b or 1c as in the embodiment shown in FIGS. 12 and 13, electric wiring can be concentrated on one side, so that the electric wiring can be shortened. Therefore, noise can be reduced when an electric signal is amplified by an amplifier or the like, which is effective.

The example of the embodiment shown in FIG. 14 is a light guide plate 22 using a scattering reflection surface 21 instead of the blaze shape as the deflecting means shown in FIG. This scattering surface 21
It is desirable to roughen the surface of the light guide plate 22 and add a film of metal or the like having a high reflectance, for example, aluminum, gold, silver, etc., to scatter without lowering the overall reflectance. in this case,
Compared with a system in which the direction of light is forcibly changed to the direction of the photoelectric conversion element 10 by the blazed shape as shown in FIG. 9, a part of the range reflected in the direction of the photoelectric conversion element 10 by scattering reflection Since only this light is propagated, the amount of light entering the photoelectric conversion element 10 is reduced. However, when resin molding is performed on the light guide plate 22 using a mold or the like, it is possible to reduce the cost of processing the mold for the blazed portion, which further reduces the cost.

As for the shape of the light guide plate, the shape shown in FIGS. 12 and 13 is used as in the case of using the blaze, that is, the photoelectric conversion element 10 is installed only on one side of the light guide plate 22a and the other side surface 12 is photoelectrically converted. The surface without the element 10 may be considered, but in the case of using a scattering / reflecting surface, the surface shown in FIG.
By tilting the surface as shown in (b), the reflected light 19 from the read object can be more effectively propagated to the photoelectric conversion element 10. On the other hand, since the embodiment shown in the explanatory view of FIG. 15 is coupled to the two light guide plates 1a and 1b respectively, a light guide 23 as illustrated in the perspective view of FIG. 16 is added to the photoelectric conversion elements 10a and 10b. It has a structure that doubles the amount of light received. The photoelectric conversion elements 10a and 10b are provided on the side surfaces of either of the two light guide plates 1a and 1b in the same direction.
And install these two light guide plates 1 on the opposite side.
A light guide 23 for optically coupling a and 1b is installed.

The light guide 23 scans the scanning line 2 of the illumination light 18 illuminating the reading target 2 such as the document surface.
It is installed so as not to interfere with 0. This light guide 23
Like the light guide plates 1a and 1b, it may be made of a material such as acrylic or glass having a high transmittance. However, since the light guide plates 1a and 1b are attached to each other by using an adhesive having a high light transmittance, It is desirable that the optical plates 1a and 1b are made of the same material as that of the optical plates 1a and 1b because problems such as expansion coefficient are eliminated. Furthermore, if the two light guide plates 1a and 1b and the light guide 23 are integrally formed of resin or the like in one mold, mass productivity is further improved.

Referring to FIG. 15 and FIG. 17 which is a sectional view taken along the line AA of FIG. 15, the illumination light 18 is applied perpendicularly to the reading object 2, and the light scattered and reflected by the reading object 2 is guided, for example. When entering the light plate 1a, the light guide plate 1a
It is turned to the left and right by the blaze 11 formed on the
The reflected light deflected to the left propagates through the light guide plate 1a as it is and is received by the photoelectric conversion element 10a.

The light deflected to the right is directed to the light guide plate 1a.
Enters the light guide 23 installed at the right end of the light guide plate 23 and propagates through the light guide 23 to obtain another light guide plate 1.
Enter b. Further, the light propagates through the light guide plate 1b and is received by the photoelectric conversion element 10b installed on the light guide plate 1b. Therefore, it becomes possible to propagate the scattered reflection light from the reading object 2 to the photoelectric conversion elements 10a and 10b by the two light guide plates 1a and 1b, and thus the amount of light received by the photoelectric conversion element 10 further increases. In addition, the photoelectric conversion element 1
By installing 0a and 10b on the side surface in the same direction,
The electric wiring can be performed on one substrate 24, and the electric wiring can be concentrated. Therefore, noise can be reduced even when the electric signal is amplified by an amplifier or the like, which is effective.

Further, the cross-sectional view of the light guide plate 1 shown in FIG. 18 is an example of an embodiment showing a structure in which the distance between the light guide plate 1 and the reading object 2 can be easily made constant especially in the longitudinal direction. It is possible to press the light guide plate 1 against the cover glass 25 by using a thick cover glass 25 with which the reading target 2 comes into contact and further illuminating the illumination light 18 in an oblique direction. Therefore, the distance to the object to be read can be kept constant especially in the longitudinal direction with the accuracy of the thickness of the cover glass 25, and the accuracy at the time of attachment is improved. Finally, Figure 1
The embodiment shown in FIG. 9 has a structure in which the light guide plate 26 has an elliptical cross section as shown in the perspective view of FIG.
In this light guide plate 26, the blaze 11 is formed on one side surface of, for example, an acrylic rod-shaped body having an elliptical cross section, and the opposite side is used as a lens, whereby the light guide plate 26 is easily manufactured.

[0029]

According to the present invention, many excellent effects as described below are expected. (1) By using the light guide plate in the reading device, it is possible to bring the object to be read close to it, so that the reflected light from the object to be read can be efficiently propagated to the photoelectric conversion element. (2) The condensing lens formed on the light guide plate can condense the reflected light from the object to be read into irregularities (blaze), so that the reflected light is more efficiently redirected toward the photoelectric conversion element. be able to. (3) By reducing the unevenness (blaze) width, it is possible to reduce the loss that occurs when the reflected light deflected by the blaze is totally reflected and propagates in the light guide plate.

(4) By forming the reflection film only on the uneven portion (blaze), the reflectance in the blaze portion is increased and the reflection loss is suppressed, while the propagation by total reflection is performed in the non-blaze portion. Propagation loss can be reduced. (5) By varying the width of the unevenness (blaze) in the longitudinal direction, a uniform output can be obtained regardless of the position of the light guide plate in the longitudinal direction. (6) By integrating the condenser lens, the concavo-convex (blaze), and the photoelectric conversion element on the light guide plate, individual optical alignment becomes unnecessary, and the assembly becomes easy. Further, regarding the light collecting system, since it can be performed only by the light guide plate, it leads to downsizing of the entire reading device.

[Brief description of drawings]

FIG. 1 is a perspective view of an illumination light scanning type document reading unit using a light guide plate used in the present invention.

FIG. 2 is a perspective view of a light guide plate mounting jig formed on a unit side wall.

FIG. 3 is an enlarged view of a locking projection at the end of the light guide plate.

FIG. 4 is a cross-sectional view of a light guide plate mounting portion.

FIG. 5 is a perspective view showing a positional relationship between a light guide plate and photoelectric conversion elements.

FIG. 6 is a perspective view of a light guide plate used in FIG.

FIG. 7 is a sectional view for explaining the effect of the lens on the light guide plate.

FIG. 8 is an explanatory diagram showing a shape of a concavo-convex portion (blaze) formed on a light guide plate.

FIG. 9 is a cross-sectional view for explaining how the reflected light propagates in the light guide plate.

FIG. 10 is a sectional view showing an example of a blaze shape.

FIG. 11 is a cross-sectional explanatory view of a laser scanning type surface inspection device using a light guide plate.

FIG. 12 is a cross-sectional view for explaining how reflected light propagates in one mode example of the light guide plate.

FIG. 13 is a cross-sectional view for explaining how reflected light propagates in another example of the light guide plate.

FIG. 14 is another example of the mode of the light guide plate using the scattering surface as the deflecting means.

FIG. 15 is an explanatory view showing an embodiment using two light guide plates and a light guide for connecting them.

16 is a perspective view of the light guide used in FIG.

17 is a cross-sectional view taken along the line AA of FIG.

FIG. 18 is a cross-sectional view showing a reading structure according to still another example of the light guide plate.

FIG. 19 is a cross-sectional view of an example using a light guide plate having an elliptical cross section.

20 is a perspective view showing a light guide plate having an elliptical cross section used in FIG.

FIG. 21 is a schematic view of a conventional illumination light scanning type document reading unit.

[Explanation of symbols]

1, 1a, 1b, 1c, 22, 22a, 26 Light guide plate 2 Read target surface (original surface) 3, 4, 5, 8 Light guide plate locking jig 6 Unit side wall 7a, 7b Screw 9a, 9b Light guide plate side Locking convex portion 10, 10a, 10b Photoelectric conversion element 11, 11a, 11b, 11c Sawtooth unevenness (blaze) 11d No blazed portion 12 Reflective surface 13, 13a Condensing lens 14 Perforated mirror 15 Polyhedral mirror 16 Lens 17 Light source 18 Illumination light 19 Reflected light 20 Scan line 21 Scattering / reflecting surface 23 Light guide 24 Photoelectric conversion element wiring board 25 Cover glass 27 Inspection target 28 Scratch

Claims (6)

[Claims] 1. A light condensing device in which illumination light scans an object to be read by an image reading device, and reflected light from the object to be read is condensed on a photoelectric conversion element by a light guide plate, wherein the light guide plate comprises: A lens function for condensing reflected light from the reading object, and a deflecting means for forming reflected light from the reading object to the photoelectric conversion element, the cross section being formed in saw-toothed concavo-convex. A condensing device comprising: 2. A light condensing device, wherein illumination light scans a reading object of an image reading device, and reflected light from the reading object is condensed on a photoelectric conversion element by a light guide plate, wherein the light guide plate comprises: While one side surface is formed into a lens shape having a function of collecting reflected light from the reading target,
A concave-convex cross section is formed on a side surface opposite to the side surface on which the lens is formed, and is used to focus reflected light from the reading target on the concave-convex and propagate it to the photoelectric conversion element. A light condensing device, which constitutes a directing means. 3. The light guide plate longitudinal direction width of the concavities and convexities having a saw-toothed cross section is formed to be narrower than the light guide plate longitudinal direction width of the lens. Concentrator. 4. The light condensing device according to claim 1, wherein a reflective film is formed on a surface of the unevenness having a sawtooth cross section. 5. The light guide plate longitudinal direction width of the concavo-convex portion having a saw-toothed cross section is formed so as to be wide near the center of the light guide plate longitudinal direction and narrow toward both ends. The light condensing device according to any one of claims 1 to 4, characterized in that: 6. The light-collecting device according to claim 1, wherein the light guide plate is provided with the lens, the diverting means, and the photoelectric conversion element integrated with each other.