Rod lens array, sensor unit, reading device, inspection device and recording system

Abstract

To provide a technique advantageous to apply a rod lens array to a reduction optical system.SOLUTION: A plurality of lens elements are aligned linearly in a normal direction of the optical axes of the lens elements in the rod lens array. The lens elements include first lens elements and second lens elements each obtained by chipping the shape of a first lens element.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a rod lens array, a sensor unit, a reading device, an inspection device, and a recording system. [Background technology]

[0002] Patent Document 1 discloses a lens array in which a large number of optical fibers having a refractive index distribution in a direction perpendicular to the optical axis are linearly arranged to form an erect life-size image. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-342131 Summary of the Invention [Problem to be solved by the invention]

[0004] When a lens array such as that shown in Patent Document 1 is applied to a reduction optical system in order to increase the depth of field, overlap of images synthesized by multiple closely spaced lenses is more likely to occur than when applied to a life-size optical system.

[0005] An object of the present invention is to provide a technique that is advantageous for applying a rod lens array to a reduction optical system. [Means for solving the problem]

[0006] In view of the above problem, a rod lens array according to an embodiment of the present invention is a rod lens array in which a plurality of lens elements are linearly arranged in a normal direction of optical axes of the plurality of lens elements, and the plurality of lens elements include a first lens element and a second lens element having a shape different from that of the first lens element. So that it becomes difficult to form an image A second lens element having a partial defect. the plurality of lens elements includes a plurality of the first lens elements and a plurality of the second lens elements, the plurality of lens elements including two first lens elements among the plurality of the first lens elements and one or more second lens elements among the plurality of the second lens elements disposed between the two first lens elements. It is characterized by the fact that Effect of the Invention

[0007] The above means provide an advantageous technique for applying a rod lens array to a reduction optical system. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a perspective view showing a configuration example of a rod lens array according to the embodiment. [Diagram 2] 2 is a perspective view showing a configuration example of a sensor unit using the rod lens array of FIG. 1. [Diagram 3] 2 is a cross-sectional view showing a structural example of the rod lens array in FIG. 1. [Figure 4] 2 is a cross-sectional view showing a structural example of the rod lens array in FIG. 1. [Diagram 5] FIG. 2 is a cross-sectional view showing a configuration example of the rod lens array in FIG. [Figure 6] FIG. 2 is a cross-sectional view showing a configuration example of the rod lens array in FIG. [Figure 7] FIG. 3 is a diagram showing a modified example of the sensor unit in FIG. 2. [Figure 8] 2 is a diagram showing an example of the configuration of a reading device, an inspection device, and a recording system in which the rod lens array of FIG. 1 is incorporated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are essential to the invention. Two or more features among the multiple features described in the embodiments may be arbitrarily combined. In addition, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0010] A rod lens array according to an embodiment of the present disclosure will be described with reference to Figs. 1(a) to 8(b). Figs. 1(a) and 1(b) are perspective views showing a configuration example of a rod lens array 100 of this embodiment. The rod lens array 100 is configured by arranging a plurality of lens elements 101 in a straight line (in a row) along a normal direction N (arrangement direction perpendicular to the optical axis) of the optical axis L of the plurality of lens elements (rod lenses) 101. The lens elements 101 include lens elements 101a and 101b having different shapes as described later, and are written as lens element "101" when no particular distinction is made, and are suffixed with lens element 101 "a" and lens element 101 "b" when distinction is necessary. In addition, the lens elements 101 (rod lenses) constituting the rod lens array 100 of this embodiment are lens elements in which both the entrance side surface and the exit side surface are flat and have a refractive index distribution within the lens element. Furthermore, this lens element 101 is a lens element that forms an erect image of an object on the image plane (forms an intermediate image).

[0011] The lens elements 101 are bonded together by a bonding material 102. In the configuration shown in Figs. 1(a) and 1(b), an example in which the lens elements 101 are arranged in a single row is shown, but the present invention is not limited to this. Two or more rows of lens elements 101 may be linearly arranged along the normal direction N. Regardless of the number of rows of lens elements 101, the rod lens array 100 may have a shape in which the direction along the normal direction N shown in Figs. 1(a) and 1(b) is the longitudinal direction.

[0012] As shown in Figs. 1(a) and 1(b), the lens elements 101 include a lens element 101a and a lens element 101b having a defect in a part of the shape of the lens element 101a. The lens element 101a exhibits a lens effect by having a refractive index distribution in a concentric circle in the normal direction of the optical axis L, for example. That is, in the lens element 101a, light is incident on a surface on one end side, and forms an image on the other end side (after exiting from the surface on the other end side). The lens element 101b is basically the same lens element as the lens element 101a. However, by performing processing described later, a defect is formed in a part of the shape of the lens element 101a. As a result, in the lens element 101b, at least a part of the light incident on the surface on one end side is blocked, and it is more difficult to form an image on the other end side than the lens element 101a. Here, almost all of the light incident on one end side (incident side) of lens element 101b may not contribute to imaging because it is attenuated by the wall surface of lens element 101b (adhesive between lens elements) or enters an adjacent lens element.

[0013] FIG. 2 is a diagram showing a sensor unit 300 using a rod lens array 100. The sensor unit 300 includes the rod lens array 100 shown in FIGS. 1(a) and 1(b), a sensor 201 for receiving light emitted from the rod lens array 100, and a frame 301 for accommodating the rod lens array 100 and the sensor 201. The sensor 201 is disposed on a substrate 202 to configure a sensor assembly 200, and the position of each sensor 201 can be fixed. In addition, the frame 301 determines the positional relationship between the rod lens array 100 and the sensor 201 that configures the sensor assembly 200. Light enters in the direction of the arrow shown in FIG. 2, passes through the rod lens array 100, and forms an image on the sensor 201.

[0014] In the sensor unit 300, there may be a need to deepen the depth of field of the rod lens array 100, for example, when imaging an object having unevenness. When the rod lens array 100 in which multiple lens elements 101 are arranged is applied to a reduction optical system in order to deepen the depth of field, the influence of overlapping of images synthesized by multiple adjacent lens elements 101 becomes large. Therefore, in this embodiment, some lens elements 101b among the multiple lens elements 101 do not form an image, or the lens elements 101b are suppressed from forming an image, thereby suppressing the influence of overlapping of images formed by the multiple lens elements 101. For example, the range in which an image of the object can be captured may be partially overlapped between adjacent lens elements 101a. On the other hand, the lens elements 101a and the lens elements 101b are arranged so that the other lens elements 101a do not form an image in the range in which one lens element 101a forms an image on the sensor 201. By providing the rod lens array 100 with such a configuration, it is possible to capture an image of the entire subject while suppressing the influence of image overlap. Here, the imaging magnification of the reduction optical system of this embodiment is about 0.3 times, but is not limited to this, and it is desirable that this imaging magnification be 0.05 times or more and 0.9 times or less (more preferably 0.15 times or more and 0.35 times or less).

[0015] For example, as shown in Fig. 2, two or more lens elements 101b may be arranged between two lens elements 101a. The number of lens elements 101b arranged between two lens elements 101a may be appropriately designed according to the acceptance angle of the lens element 101 and the arrangement pitch of photoelectric conversion elements and the like arranged in the sensor 201. The number of lens elements 101b arranged between two lens elements 101a may be the same between any two lens elements 101a, or may be partially different depending on the arrangement of the sensor 201 and the like. For example, when there is a joint of the sensor 201 at a position corresponding to the position between the two lens elements 101a, the number of lens elements 101b between the two lens elements 101a may be greater than when there is no joint of the sensor 201 at a position corresponding to the position between the two lens elements 101a.

[0016] Returning to Figs. 1(a) and 1(b), lens element 101b, which has a missing portion with respect to the shape of lens element 101a, will be further described. As shown in Fig. 1(a), slits (holes) 111 may be provided in lens element 101b so that lens element 101b is not continuous between one end and the other end. For example, by providing a slit as shown in Fig. 1(a), it becomes difficult for lens element 101b to form an image of a subject (form an image of a subject). On the other hand, slit 111 is not provided at a position corresponding to lens element 101a, and lens element 101a is continuous between one end and the other end, and is therefore capable of forming an image of a subject (form an image of a subject).

[0017] Also, as shown in FIG. 1(b), the surface on one end side of the lens element 101b may be rougher than the surface on one end side or the surface on the other end side of the lens element 101a. For example, the lens element 101b can be obtained by roughening the surface on one end side of the lens element 101a using a file or the like. The roughened surface on one end side can be disposed on the side where light is incident in the sensor unit 300, as shown in FIG. 2. By roughening the surface on one end side of the lens element 101b, the incident light is refracted in various directions, making it difficult to form an image. For example, when the incident light is refracted on the surface on one end side of the lens element 101b and enters the bonding material 102 from the lens element 101b, the light can be absorbed in the bonding material 102. In this way, the bonding material 102 may function as a light blocking material. The bonding material 102 can be an adhesive or the like for bonding a plurality of lens elements 101. By adding a black paint or the like to the adhesive, light is absorbed in the binder 102, making it difficult for the light to pass through the lens element 101b. Even if the binder 102 is transparent, the light incident on the binder 102 from the lens element 101b travels to a position far away from the original bonding position, making it difficult for the light to contribute to image formation. For example, both ends of the lens element 101b may be roughened. Also, the slit 111 shown in FIG. 1(a) and the roughening of the end portion shown in FIG. 1(b) may be combined.

[0018] Also, for example, as shown in Figs. 3(a) and 3(b), the shape of the surface on one end side of lens element 101b may be conical. For example, lens element 101b may be formed by disposing cutting tool 151 such as a drill at a position corresponding to each of lens elements 101b and cutting. Light incident from object 411 illuminated by illumination device 401 passes through lens element 101a (lens action is not depicted in Fig. 3(b). The same applies to the following figures). On the other hand, since the surface on one end side of lens element 101b is conical, light incident on lens element 101b is refracted in the direction of the interface between lens element 101b and bonding material 102 as shown in Fig. 3(b), and it becomes difficult for the light to pass through lens element 101b. In other words, lens element 101b becomes difficult to form an image.

[0019] Next, the angle of the surface on one end side of the lens element 101b will be described. The inclination θ of the surface on one end side of the lens element 101b shown in FIG. 3(b) with respect to the normal direction (for example, normal direction N) may be equal to or larger than the angle of the acceptance angle of the lens element 101a. Here, the acceptance angle is the maximum angle between the optical axis and a light beam that can be imaged by the lens element 101 among the light beams that enter the position where the light incident surface of the lens element 101a intersects with the optical axis. The acceptance angle may also be called the aperture angle. This acceptance angle (aperture angle) is 9 degrees in this embodiment, but may be 12 degrees, and is preferably 3 degrees or more and 21 degrees or less (4.8 degrees or more and 12.3 degrees or less). By setting the inclination θ to an angle 1.5 times or more of the acceptance angle, almost all of the light that enters the lens element 101b can be blocked from the sensor 201 (prevented from entering the sensor 201). Furthermore, the inclination θ of the surface on one end side of the lens element 101b with respect to the normal direction may be an angle of twice or more (more preferably three times or more) the acceptance angle of the lens element 101a. Moreover, it is desirable that this inclination θ is six times or less (more preferably five times or less) the acceptance angle. The lens element 101 used in the rod lens array 100 may have an acceptance angle of about 9° as described above. Therefore, the inclination θ of the surface on one end side of the lens element 101b with respect to the normal direction may be 13.5° or more. Furthermore, taking into consideration a margin, the inclination θ of one end of the lens element 101b with respect to the normal direction N may be 18° or more (preferably 27° or more). In Figs. 3(a) and 3(b), a case is shown in which the processing is performed with a cutting tool 151 such as a drill, the tip of which has an inclination of about 90°, and the inclination θ is about 45°.

[0020] In the configuration shown in Figures 3(a) and 3(b), conical recesses are formed to correspond to each of the lens elements 101b, but this is not limited to this. For example, as shown in Figures 4(a) and 4(b), multiple conical recesses may be formed in one lens element 101b, or one conical recess may be formed across two or more lens elements 101b.

[0021] Furthermore, for example, as shown in Figures 5(a) to 5(c), a surface on one end side of lens element 101b may be inclined with respect to a surface on one end side of lens element 101a. Here, Figures 3(a) to 4(b) show cross sections in which multiple lens elements 101 are arranged in the horizontal direction of the figures, while Figures 5(a) to 5(c) show cross sections in which multiple lens elements 101 are arranged in the depth direction of the figures.

[0022] As shown in FIG. 5(a), light incident on lens element 101a passes through lens element 101a. On the other hand, lens element 101b is cut obliquely using cutting tool 151 such as an end mill. Therefore, light incident on lens element 101b is refracted toward the interface between lens element 101b and bonding material 102 as shown in FIG. 5(b), and it becomes difficult for the light to pass through lens element 101b. In other words, lens element 101b becomes difficult to form an image. As described above, bonding material 102 may function as a light blocking material. Furthermore, lens element 101b may not only be obliquely inclined in one direction as shown in FIG. 5(b), but may also be obliquely inclined in both directions intersecting the direction in which multiple lens elements 101 are arranged as shown in FIG. 5(c). As described above, the inclination θ of one end of lens element 101b shown in Figures 5(b) and 5(c) with respect to the normal direction of the optical axis may be equal to or greater than the acceptance angle of lens element 101a. Furthermore, the inclination θ of one end of lens element 101b with respect to the normal direction of the optical axis may be an angle three times or more the acceptance angle of lens element 101a. Moreover, the inclination θ of one end of lens element 101b with respect to the normal direction N may be 9° or more, or even 27° or more.

[0023] In this way, some of the lens elements (lens elements 101b) among the multiple lens elements 101 are processed to make it difficult for them to form an image. This makes it possible to apply the rod lens array 100 to a reduction optical system and deepen the depth of field while suppressing degradation in image quality caused by overlapping of images synthesized by multiple adjacent lenses.

[0024] In the sensor unit 300, it is conceivable to arrange a plurality of lens elements at a predetermined interval without using the rod lens array 100 having the lens elements 101a and 101b. However, in order to arrange the lens elements of about φ1.0 mm with the optical axes aligned at a predetermined interval according to the positions of the photoelectric conversion elements and the like arranged in the sensor 201, high accuracy is required, which may cause an increase in cost. On the other hand, in this embodiment, since a rod lens array generally used in the sensor unit 300 and the like is processed, the accuracy when assembling the rod lens array 100 in the sensor unit 300 and the like may be equivalent to that when a normal sensor unit 300 is manufactured. In addition, the rod lens array 100 can be manufactured by adding relatively easy processing such as forming the above-mentioned slit 111, roughening the surface on one end side of the lens element 101a, forming a conical recess, and tilting the surface to a general-purpose rod lens array, and therefore the impact on costs can be suppressed.

[0025] In addition, in order to shield some of the lens elements 101 from light, it is possible to arrange a light shielding member on some of the lens elements among the lens elements 101 arranged in a general-purpose rod lens array. For example, it is possible to arrange a metal plate or a resin plate with a part opened so as to cover the rod lens array as the light shielding member. However, due to differences in structure, the light shielding member is likely to have a linear expansion coefficient different from that of the rod lens array. Therefore, it is difficult to align the light shielding member with each lens element 101 of the rod lens array 100 in response to environmental changes such as temperature and the elongation of the sensor unit 300. On the other hand, in this embodiment, the lens elements 101 arranged in the rod lens array 100 themselves are processed, so that it is easy to respond to environmental changes and the elongation of the sensor unit 300.

[0026] Next, a modified example of the rod lens array 100 will be described with reference to FIG. 6. In order to make it difficult for the lens element 101b to form an image, the surface of one end side of the lens element 101b, which is missing with respect to the shape of the lens element 101a, may be covered with a light shielding member 112. For example, as shown in FIG. 6, a colored resin such as black may be embedded in the part of the surface of the one end side of the lens element 101b, which is missing. Also, for example, a metal film may be formed as the light shielding member 112 in the part of the surface of the one end side of the lens element 101b, which is missing. The light shielding member 112 does not need to cover the entire end face of the lens element 101b, and may cover only a part of it. By disposing the light shielding member 112, it becomes more difficult for light to pass through the lens element 101b.

[0027] 7(a) and 7(b) are diagrams showing modified examples of the sensor unit 300 shown in FIG. 2. As with the sensor unit 300 shown in FIG. 2, the sensor unit 300 shown in FIG. 7(a) includes a rod lens array 100, a sensor 201 for receiving light emitted from the rod lens array 100, and a frame 301 for accommodating the rod lens array 100 and the sensor 201. In the configuration shown in FIG. 7(a) and 7(b), the surface on one end side of the lens element 101b arranged in the rod lens array 100 is cut using, for example, a cutting tool 151 to form a recess, as shown in FIG. 3(a) to 5(c). Also, as with the configuration shown in FIG. 2, the surface on the other end side opposite to the surface on one end side of the lens element 101b where a defect (recess) occurs in the shape of the lens element 101a is arranged to face the sensor 201.

[0028] At this time, as shown in Figs. 7(a) and 7(b), one end side of the lens element 101b having a recess may be used for alignment between the rod lens array 100 and the frame 301. Fig. 7(a) is an exploded perspective view of the sensor unit 300, and Fig. 7(b) is a cross-sectional view of the portion 160 of Fig. 7(a). As described above, the surface on one end side of the lens element 101b has a recess. A reference pin 302 is disposed on the frame 301 so as to fit into the recess of the lens element 101b. When the rod lens array 100 is assembled into the frame 301, the recess of the lens element 101b fits into the reference pin 302, which can facilitate alignment of the rod lens array 100 with respect to the frame 301.

[0029] As shown in Fig. 7(b), the recesses into which the reference pins 302 are inserted and the recesses into which the reference pins 302 are not inserted among the plurality of lens elements 101b may have different shapes. Also, the recesses into which the reference pins 302 are inserted and the recesses into which the reference pins 302 are not inserted among the plurality of lens elements 101b may have the same shape. If the recesses into which the reference pins 302 are inserted and the recesses into which the reference pins 302 are not inserted have different shapes, it may be easier to align the rod lens array 100 and the frame 301. Even if the slits 111 are formed in the rod lens array 100, a recess of an appropriate shape may be formed on the surface on one end side of the lens elements 101b so as to fit with the reference pins 302.

[0030] Next, as application examples of the rod lens array 100 of this embodiment, a reading device, an inspection device, and a recording system including a sensor unit 300 incorporating the rod lens array 100 will be described. Fig. 8(a) is a diagram for explaining a reading device 400 including a sensor unit 300 incorporating the rod lens array 100, and an inspection device 500 including the reading device 400. Fig. 8(b) is a diagram for explaining a reading device 400 including a sensor unit 300 incorporating the rod lens array 100, and a recording system 510 including the reading device 400.

[0031] 8(a) and 8(b), the reading device 400 includes an illumination device 401 and an image sensor 402 for acquiring image information of an illuminated object 411 (subject) illuminated by the illumination device 401. The image sensor 402 is provided with a sensor unit 300 incorporating the above-mentioned rod lens array 100. As shown in FIGS. 1(b) and 3(a) to 5(c), when the surface on one end side of the lens element 101b is processed, the surface on one end side of the lens element 101b where a defect occurs with respect to the shape of the lens element 101a can be disposed so as to face the illuminated object 411.

[0032] 8(a) and 8(b), a large depth of field is required for imaging. Therefore, by providing the rod lens array 100 with the above-mentioned configuration, the reading device 400 including the sensor unit 300 incorporating the rod lens array 100 can focus on the illuminated objects 411 of different sizes.

[0033] The reading device 400 that can be focused on the illuminated object 411 of different sizes can be applied to an inspection device 500 as shown in FIG. 8(a), for example. The inspection device 500 can include the reading device 400 and a determiner 501 that determines the quality of the illuminated object 411 using image information acquired by the reading device 400. The inspection device 500 may also include a conveying device 502 for conveying the illuminated object 411 as shown in FIG. 8(a). The inspection device 500 may include, for example, a sensor unit 300 (line sensor unit) including a linear rod lens array 100 and a sensor 201, and may be an inspection device that inspects the illuminated object 411 moving on the conveying device 502. The reading device 400 that can be focused on the illuminated object 411 of different sizes can improve the accuracy of the inspection by the inspection device 500.

[0034] Moreover, the reading device 400 that can adjust the focus to the illuminated object 411 of different sizes can be applied to a recording system 510 as shown in FIG. 8(b), for example. The recording system 510 includes the reading device 400 and a recording device 511 that records on a recording medium based on image information acquired by the reading device 400. The recording system 510 includes a copier, a printer, a data recording device that records data on a hard disk or a memory, and the like. FIG. 8(b) shows an example of the recording system 510 that records on a paper medium such as a copier or a printer. The recording system 510 may capture an image while moving the illuminated object 411 like the above-mentioned inspection device 500, or may capture an image of the illuminated object 411 by moving the reading device 400. Even if the illuminated object 411 is uneven, as shown in Figure 8 (b), a recording system 510 equipped with a reading device 400 including a sensor unit 300 incorporating a rod lens array 100 can record an in-focus image on the surface of the illuminated object 411.

[0035] The recording device 511 can record an image including characters on a recording medium 513 (for example, paper) by any method such as an inkjet method or an electrophotographic method. In this case, the recording system 510 can include a conveying device 512. As the conveying device 512, a conveying roller that conveys the recording medium from upstream to downstream can be used. In one embodiment, the recording system 510 can perform a copy process, and in this case, the recording device 511 records the image information read by the reading device 400 on the recording medium as an image. In one embodiment, the recording system 510 can perform feedback control. For example, the reading device 400 can read the image information on the recording medium 513 after recording by the recording device 511 and transmit it to the recording device 511 as read data. Based on this read data, the recording device 511 can check the recording state on the recording medium and control the recording parameters for the next recording.

[0036] Furthermore, the recording system 510 is not limited to a device that records on a recording medium 513 such as paper, as described above. The recording device 511 may record image information read by the reading device 400 as electronic data on a recording medium such as a hard disk or memory. In this case, the recording device 511 may include a recording medium such as a hard disk or memory. In this case, the recording system 510 does not need to include the transport device 512.

[0037] The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the gist of the invention. [Explanation of symbols]

[0038] 100: rod lens array, 101a, 101b: lens elements

Claims

1. A rod lens array in which a plurality of lens elements are linearly arranged in a normal direction to optical axes of the plurality of lens elements, the plurality of lens elements include a first lens element and a second lens element having a defect in a portion thereof so that it is difficult to form an image due to a shape of the first lens element, the plurality of lens elements includes a plurality of the first lens elements and a plurality of the second lens elements, A rod lens array characterized in that the plurality of lens elements include two first lens elements among the plurality of first lens elements, and one or more second lens elements among the plurality of second lens elements arranged between the two first lens elements.

2. A rod lens array as described in claim 1, characterized in that two or more of the second lens elements are arranged between the two first lens elements.

3. 3. The rod lens array according to claim 1, wherein a surface of the second lens element on one end side is rougher than a surface of the first lens element on one end side.

4. 4. The rod lens array according to claim 1, wherein a surface on one end side of the second lens element is inclined with respect to a surface on one end side of the first lens element.

5. 5. The rod lens array according to claim 1, wherein the shape of a surface on one end side of the second lens element is conical.

6. 6. The rod lens array according to claim 4, wherein an inclination of a surface on one end side of the second lens element with respect to the normal direction is equal to or greater than an acceptance angle of the first lens element.

7. 6. The rod lens array according to claim 4, wherein an inclination of a surface on one end side of the second lens element with respect to the normal direction is 9 degrees or more.

8. 8. The rod lens array according to claim 3, wherein a surface of the second lens element on one end side where a defect occurs with respect to the shape of the first lens element is covered with a light blocking member.

9. 9. The rod lens array according to claim 1, wherein the second lens element is discontinuous between one end and the other end.

10. A rod lens array according to any one of claims 1 to 9; a sensor for receiving light emitted from the rod lens array; a frame that houses the rod lens array and the sensor; A sensor unit comprising:

11. The sensor unit according to claim 10 , wherein a surface on the other end side of the second lens element opposite to a surface on one end side where a defect occurs with respect to the shape of the first lens element faces the sensor.

12. A lighting device; an image sensor for acquiring image information of an object illuminated by the illumination device, A reading device, wherein the image sensor includes the sensor unit according to claim 10 or 11.

13. 13. The reading device according to claim 12, wherein a surface on one end side of the second lens element, which is missing relative to the shape of the first lens element, is disposed so as to face the object to be illuminated.

14. A reading device according to claim 12 or 13, a determiner for determining whether the illuminated object is good or bad using the image information acquired by the reading device; An inspection device comprising:

15. A reading device according to claim 12 or 13, a recording device that records the image information acquired by the reading device on a recording medium; A recording system comprising:

Images