Optical member and image reading apparatus

Abstract

An optical member (1) includes a lens array (6) having a plurality of lens bodies (5), and a plurality of transmission members (7). The plurality of transmission members (7) are formed of members having the same refractive index, and are respectively provided at positions closer to a reading target object (D) than the corresponding lens bodies (5) or at positions farther from the reading target object (D) than the lens bodies (5). Each transmission member (7) has a columnar shape extending along an optical axis of the lens body (5), and causes light incident from one end surface to be emitted from the other end surface. Each optical axis (AX1) of the lens bodies (5) and a central axis (C1) of the transmission member (7) corresponding to the lens body (5) are offset at least in a sub-scanning direction, whereby the end surface of each lens body (5) opposes only the end surface of the corresponding transmission member (7).

Description

Technical Field

[0001] This disclosure relates to optical components and image reading devices. Background Technology

[0002] Image reading devices include those that illuminate an object to be read, focus transmitted or reflected light from the object through a plurality of lenses arranged in an array, and then read the light by a plurality of photosensitive elements arranged in a line. An example of such an image reading device is disclosed in Patent Documents 1 and 2.

[0003] Lens arrays used as image reading devices employ upright equal-magnification optical systems, specifically rod-shaped lens arrays or microlens arrays with multiple cylindrical lens bodies.

[0004] In order to increase the depth of field when using the above-described lens array, the image reading apparatus disclosed in Patent Documents 1 and 2 includes an overlap limiting member disposed between the lens elements. By using the overlap limiting member to limit the overlap of images caused by multiple lens elements, the imaging diameter of each lens element can be controlled, thereby increasing the depth of field.

[0005] As an example of an overlap-limiting component, the image reading device disclosed in Patent Document 2 includes a light-transmitting cylindrical array having multiple light-transmitting cylindrical portions. The light-transmitting cylindrical portions are arranged between the lens array and the sensor array according to each optical axis of the lens body, so that light incident from one end face of the lens body exits towards the sensor element from the other end face. By adjusting the length of the light-transmitting cylindrical portions along the optical axis, overlap of images formed by the lens body can be prevented.

[0006] Patent Document 1: Japanese Patent Application Publication No. 6-342131

[0007] Patent Document 2: International Publication No. 2020 / 196168

[0008] The image reading device disclosed in Patent Document 2 includes: lens bodies that abut against each other, and light-transmitting cylindrical portions that are respectively arranged and abut against each other for each lens body. If the optical axis of the lens body is misaligned with the central axis of the light-transmitting cylindrical portion, light emitted from the lens body will be incident on the light-transmitting cylindrical portion adjacent to the light-transmitting cylindrical portion corresponding to that lens body. As a result, sometimes overlapping images formed by adjacent lens bodies will occur. Summary of the Invention

[0009] This disclosure was made to solve the aforementioned problems, and aims to provide an optical component and an image reading device that suppresses the overlap of images formed by a lens even when errors occur in the arrangement position of at least one of the lens body and the transmission component that limits the overlap of images formed by the lens body.

[0010] The optical component disclosed herein includes a lens array and multiple transmitting elements. The lens array has multiple lens bodies arranged in a row along the main scanning direction to converge light from the object being read. The multiple transmitting elements are formed of components with the same refractive index and are respectively positioned closer to or farther from the object being read than the corresponding lens body. They have a cylindrical shape extending along the optical axis of the lens body, allowing light incident from one end face to exit from the other end face. The cross-sectional shape of the lens body in the plane perpendicular to the optical axis, i.e., the plane perpendicular to the optical axis, is such that the length of the main scanning direction from the position across the optical axis offset in the sub-scanning direction intersecting the main scanning direction is shorter than the length of the main scanning direction at the position across the optical axis. The cross-sectional shape of the transmitting element in the plane perpendicular to the optical axis is such that the length of the main scanning direction from the position across the central axis offset in the sub-scanning direction is shorter than the length of the main scanning direction at the position across the central axis of the transmitting element. Each optical axis of the lens body is offset from the central axis of the corresponding transmission component of the lens body at least in the sub-scanning direction, so that the end face of each lens body faces only the end face of the corresponding transmission component.

[0011] According to the optical component disclosed herein, it is possible to obtain an optical component that suppresses the overlap of images formed by adjacent lens bodies even if there is an error in the arrangement position of at least one of the lens bodies and the transmission component. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view of the image reading device according to Embodiment 1.

[0013] Figure 2 This is a perspective view of the optical component according to Embodiment 1.

[0014] Figure 3 This is an exploded perspective view of the optical component of Embodiment 1.

[0015] Figure 4 This is a perspective view of the through-hole component in Embodiment 1.

[0016] Figure 5 This is a diagram showing the positional relationship between the lens and the transmission component in the optical component used as a comparative example.

[0017] Figure 6 This is a diagram showing the positional relationship between the optical components and the sensor array in Embodiment 1.

[0018] Figure 7 This is a diagram showing the positional relationship between the lens and the transmission component of the optical component in Embodiment 1.

[0019] Figure 8 This is a diagram showing the positional relationship between the optical components and the sensor array in Embodiment 2.

[0020] Figure 9 This is a diagram showing the positional relationship between the lens and the transmission component of the optical component in Embodiment 2.

[0021] Figure 10 This is a diagram showing the positional relationship between the lens and the transmission component in the optical component used as a comparative example.

[0022] Figure 11 This is a cross-sectional view of a first modified example of the image reading device according to the embodiment.

[0023] Figure 12 This is a cross-sectional view of a second variation of the image reading device according to the embodiment.

[0024] Figure 13 This is a cross-sectional view of a third variation of the image reading device according to the embodiment. Detailed Implementation

[0025] Hereinafter, the optical components and image reading device of the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Furthermore, the same reference numerals are used to denote the same or equivalent parts in the drawings.

[0026] (Implementation Method 1)

[0027] For example, taking an image reading device that reads images, text, patterns, and other information on the surface of the object being read, such as a sheet-like component, substrate, or mesh of sheet-like fibers (including documents, banknotes, securities, etc.), as an example, the image reading device 2 of Embodiment 1 will be described using the accompanying drawings. Figure 1 In the image reading device 2 shown, the main scanning direction is set as the X-axis, the sub-scanning direction is set as the Y-axis, and the reading depth direction is set as the Z-axis. The main scanning direction and the sub-scanning direction intersect, preferably orthogonally. In Embodiment 1, the X-axis, Y-axis, and Z-axis are orthogonal to each other. The same applies in the following figures.

[0028] As shown in the diagram of a cross-section along the sub-scanning direction of the image reading device 2, that is... Figure 1As shown, the image reading device 2 includes: a light source 9 that emits light toward the object D to be read; a transmission plate 10 that allows light emitted from the light source 9 to pass through; and an optical component 1 having a plurality of lenses that converge the light reflected from the object D. The image reading device 2 also includes: a sensor array 4 having a plurality of sensor elements 3 that receive the light converged by the optical component 1; and a sensor substrate 11 for mounting the sensor array 4. The image reading device 2 also includes a frame 12 for mounting the transmission plate 10 and the sensor substrate 11, and internally housing the light source 9, the optical component 1, and the sensor array 4.

[0029] like Figure 1 As indicated by the dashed arrow, light source 9 is a linear light source that illuminates a line of light at the location through which the object being read, D, passes, i.e., the reading position. It may be formed, for example, by a side-light source. A side-light source is a light source having a light guide extending along the X-axis and a light source element disposed at the X-axis end of the light guide. The light emitted from light source 9 and used to read information from the object being read, D, is, for example, visible light.

[0030] A plate 10 is installed on the frame 12 to block the opening 12a of the frame 12 facing the object being read, and is thus mounted on the frame 12. The plate 10 allows light emitted from the light source 9 to pass through. More specifically, as... Figure 1 As indicated by the dashed arrow, the transmissive plate 10 is formed of a component with high transmittance, such as transparent glass or transparent resin, to a degree that the light emitted by the light source 9 can illuminate the object to be read, and the light from the object to be read, can be received by the sensor element 3. The transmissive plate 10 has a flat, plate-like shape with two flat surfaces extending along the main scanning direction and the sub-scanning direction. In the transmissive plate 10, the surface opposite to the surface of the opening 12a of the blocking frame 12 forms the reading surface of the object to be read, D. The reading surface limits the reading position of the object to be read, D.

[0031] The frame 12 has a box-shaped form with an opening 12a facing the object being read, and an opening 12b facing the opposite side of the opening 12a. The frame 12 is made of a component that shields light from the outside, such as a metal including aluminum, iron, or resin. The light source 9, optical component 1, and sensor array 4, which are housed in the frame 12, are directly or indirectly mounted on and held in the frame 12. The frame 12 suppresses light from entering the light-receiving part, specifically the sensor element 3, from the outside of the image reading device 2. Furthermore, the frame 12 prevents foreign objects such as dust and moisture from entering the interior of the image reading device 2.

[0032] The sensor substrate 11 is a substrate formed of resin, such as glass epoxy resin. Multiple sensor elements 3 and other components (not shown), such as drive circuitry and signal processing circuitry, are disposed on the sensor substrate 11. The sensor substrate 11 is mounted on the frame 12 with the opening 12b of the sensor element 3 located at the lower vertical position of the frame 12 blocked.

[0033] Multiple sensor elements 3 are arranged along the main scanning direction and fixed to the sensor substrate 11 by fixing components such as adhesives. Each sensor element 3 is positioned relative to a lens body 5 and receives light converged by the corresponding lens body 5. Each sensor element 3 is preferably positioned where the optical axis AX1 of the corresponding lens body 5 passes. For example, each sensor element 3 is formed by a sensor IC (Integrated Circuit). The sensor element 3 receives the light converged by the corresponding lens body 5, performs photoelectric conversion to convert it into an electrical signal, and outputs it. The electrical signal output by the sensor element 3 is converted into image information by a signal processing circuit. The optical axis AX1 of the lens body 5 is parallel to the Z-axis. The XY plane is perpendicular to the optical axis AX1 of the lens body 5. The XY plane is also referred to as the optical axis perpendicular plane.

[0034] like Figure 2 as well as Figure 3 As shown, the optical component 1 includes: a lens array 6 having a plurality of lens bodies 5 arranged in a row along the main scanning direction; and a transmission component array 8 having a plurality of transmission components 7 that allow light incident from one end face to exit from the other end face.

[0035] The lens array 6 has multiple lens bodies 5 and two side plates 56 that hold the multiple lens bodies 5. In embodiment 1, the multiple lens bodies 5 are arranged along the main scanning direction in a state of mutual contact. Each lens body 5 converges the light from the object being read, D. The extension direction of the optical axis AX1 of the lens body 5 is orthogonal to both the main scanning direction and the sub-scanning direction. In other words, the optical axis AX1 of the lens body 5 extends parallel to the Z-axis. The lens body 5 converges the light emitted from the light source 9 and reflected by the object being read, D. The lens body 5 is preferably cylindrical in shape, with different refractive indices in the radial direction, and is formed by a refractive index distribution type lens, i.e., a rod lens, that forms an upright, equal-magnification image.

[0036] Two side plates 56 are positioned opposite each other in the Y-axis direction, spaced apart by multiple lens bodies 5. The side plates 56 are formed of a flat, light-shielding component, such as a metal including aluminum or iron, or resin. Preferably, a light-shielding adhesive is filled between the two side plates 56. This suppresses relative positional misalignment between the lens bodies 5 and the side plates 56.

[0037] The transmission element array 8 prevents the images formed by adjacent lens bodies 5 from overlapping; in other words, it separates the light paths converged by adjacent lens bodies 5. The transmission element array 8 has a plurality of transmission elements 7 and two side plates 78 that hold the plurality of transmission elements 7. In embodiment 1, the plurality of transmission elements 7 are arranged along the main scanning direction in a state of mutual contact.

[0038] Each transmitting component 7 is provided for each lens body 5, and is positioned either closer to the object to be read D than the corresponding lens body 5, or further away from the object to be read D. In Embodiment 1, the transmitting component 7 is located further away from the object to be read D than the lens body 5; in other words, it is located between the lens body 5 and the sensor element 3. Each transmitting component 7 is positioned with its end abutting against the end of the lens body 5 in the direction of the optical axis AX1, specifically, the end on the negative Z-axis direction.

[0039] The transmitting components 7 are offset from the corresponding lens body 5 at least in the sub-scanning direction, that is, at least in the Y-axis direction, and arranged in a row along the main scanning direction. In Embodiment 1, multiple transmitting components 7 are offset from multiple lens bodies 5 in the Y-axis direction and arranged in a row along the X-axis direction. In other words, the optical axes AX1 of each lens body 5 are offset from the central axis C1 of the transmitting component 7 corresponding to that lens body 5 at least in the sub-scanning direction.

[0040] The transmitting component 7 is formed of a component with the same refractive index regardless of its position, and has a cylindrical shape extending along the optical axis AX1 of the lens body 5. A component with the same refractive index means that the refractive index at any position of the component is within a specified range of permissible manufacturing tolerances. For example, the transmitting component 7 is a cylindrical component made of glass or resin with the same refractive index and transmittance regardless of its position. The transmitting component 7 is preferably formed of a component with sufficiently low distortion, for example, a component without distortion. In Embodiment 1, the transmitting component 7 has a cylindrical shape with the same diameter as the lens body 5.

[0041] The light emitted from the light source 9 is transmitted through the transmission component 7. Specifically, the transmission component 7 allows light to enter from one end face and exit from the other end face. In Embodiment 1, the transmission component 7 allows light that enters from the lens body 5 and is directed toward the end face of the lens body 5, i.e., toward the positive Z-axis direction, to exit from the end face of the sensor element 3, i.e., toward the negative Z-axis direction.

[0042] Two side plates 78 are positioned opposite each other in the Y-axis direction, spaced apart by multiple transparent elements 7. The side plates 78 are formed of a flat, light-shielding material, such as a metal including aluminum or iron, or resin. Preferably, a light-shielding adhesive is filled between the two side plates 78. This suppresses any relative positional misalignment between the transparent elements 7 and the side plates 78.

[0043] The side surface of the transmissive component 7, in other words, the outer peripheral surface of the transmissive component 7 around the Z-axis, is subjected to at least one of the following treatments: a treatment to suppress the diffuse reflection of light incident from the outside to the side surface, and a treatment to suppress the direct reflection of light incident from the outside to the side surface. In Embodiment 1, as... Figure 4 As shown, the transmissive component 7 has a cylindrical component 71 and a reflection-suppressing component 72 formed by a cylindrical component whose inner circumferential surface abuts against the outer circumferential surface of the cylindrical component 71. Specifically, the transmissive component 7 is formed by coating the outer circumferential surface of the cylindrical component 71 with a reflection-suppressing component 72 made of black resin. The reflection-suppressing component 72, made of black resin, suppresses light reflection at the side surfaces of the transmissive component 7. Furthermore, the reflection-suppressing component 72 absorbs light that travels from the interior of the transmissive component 7 through the side surfaces to the exterior. Alternatively, a light-shielding adhesive filled between the two side plates 78 can be used as the reflection-suppressing component 72.

[0044] exist Figure 5 A comparative example is shown where the lens body and the transmitting component are not offset in the sub-scanning direction. Although Figure 5 The structure of the image reading device 90 shown is the same as that of the image reading device 2, but it differs from the image reading device 2 in that the plurality of lens bodies 91 and the plurality of transmission components 92 are not offset in the Y-axis direction. Figure 5 This is a diagram showing the lens array of the image reading device 90 viewed along the positive Z-axis. Figure 5 In the diagram, solid lines represent the outline of the lens body 91, and dashed lines represent the outline of the transmitting component 92. Multiple lens bodies 91 are arranged along the main scanning direction in a contacting state. Multiple transmitting components 92 are arranged along the main scanning direction in a contacting state.

[0045] If, due to manufacturing errors, the diameter of the transmitting component 92 is smaller than the diameter of the lens body 91, then the central axis of each transmitting component 92 will be offset from the optical axis of each lens body 91. As a result, for example, Figure 5 The end face of the transmitting member 92 at the left end faces and abuts against the end faces of the two lens bodies 91 located at the left end. Therefore, light emitted from the two adjacent lens bodies 91 enters a transmitting member 92, resulting in the superposition of images formed by the two adjacent lens bodies 91.

[0046] like Figure 5 As shown, the following describes the structure for suppressing the end face of a transmission member 92 from facing the end faces of multiple lens bodies 91.

[0047] like Figure 6 And a diagram showing the lens array 6 viewed in the positive Z-axis direction. Figure 7 As shown, due to manufacturing errors in the transmitting component 7, sometimes the diameter of the transmitting component 7 is smaller than the diameter of the lens body 5. In Embodiment 1, as... Figure 1 As shown, each optical axis AX1 of the lens body 5 is offset from the central axis C1 of the transmission component 7 corresponding to the lens body 5 in the sub-scanning direction.

[0048] In detail, on the XY plane, the contact point L1 of the two abutting lens bodies 5 and the contact point L2 of the two transmitting components 7 corresponding to the two abutting lens bodies 5 and abutting each other are offset at least in the sub-scanning direction.

[0049] For example, in Figure 7 In the XY plane, the contact point L1 of two lens bodies 5 located at their centers and abutting each other along the X-axis, and the contact point L2 of two transmission components 7 located at their centers and abutting each other along the X-axis, are offset along the Y-axis. Additionally, for example, in... Figure 7 In the middle, the contact point L1 of the two lens bodies 5 located at the left end and abutting each other and the contact point L2 of the two transmission components 7 located at the left end and abutting each other are offset in the Y-axis direction and the Z-axis direction, respectively.

[0050] As described above, each optical axis AX1 of the lens body 5 is offset from the central axis C1 of the transmitting component 7 corresponding to the lens body 5 at least in the sub-scanning direction. Figure 7 As shown, the end face of each transmitting component 7 does not face the end faces of the multiple lens bodies 5, but only faces the end face of the corresponding lens body 5.

[0051] like Figure 6 As shown in Figure 7, the end face of the lens body 5 is offset from the end face of the corresponding transmitting member 7. Therefore, a portion of the light emitted from the lens body 5 does not incident on the transmitting member 7 corresponding to that lens body 5, i.e., the transmitting member 7 that abuts against that lens body 5, but instead enters towards the adjacent transmitting member 7. The end face of each transmitting member 7 does not face the end faces of the plurality of lens bodies 5. Therefore, as described above, light towards the adjacent transmitting member 7 does not incident on that transmitting member 7, but instead enters towards the side of the transmitting member 7.

[0052] As described above, a reflection suppression member 72 is provided on the side of the transmitting member 7, so that light reaching the side of the adjacent transmitting member 7 is absorbed. The central axis C1 of the transmitting member 7 is offset from the optical axis AX1 of the lens body 5 at least in the sub-scanning direction. The reflection suppression member 72 is provided on the side of the transmitting member 7, thereby separating the optical path of the light converged by the adjacent lens bodies 5. As a result, the overlap of images formed by two mutually adjacent lens bodies 5 is suppressed.

[0053] like Figure 6As indicated by the arrows in the solid line, a portion of the light incident from the lens 5 onto one end face of the transmitting member 7 travels inside the transmitting member 7 and reaches the sensor element 3. Another portion of the light incident from the lens 5 onto one end face of the transmitting member 7 reaches the side face of the transmitting member 7. If the angle of incidence when reaching the side face of the transmitting member 7 is above the critical angle, the light undergoes total internal reflection, travels within the transmitting member 7, and reaches the sensor element 3. When light incident at a large angle relative to the central axis C1 onto one end face of the transmitting member 7 reaches the side face of the transmitting member 7, the angle of incidence at the side face of the transmitting member 7 is small, therefore total internal reflection does not occur; instead, it is refracted and incident on the reflection suppression member 72 located on the side face of the transmitting member 7, where it is absorbed.

[0054] By lengthening the extension direction of the optical axis AX1 of the lens body 5, in other words, the length of the transmitting member 7 in the Z-axis direction, the situation where light incident from one end face of the transmitting member 7 does not reach the side face of the transmitting member 7 but exits directly from the other end face is suppressed. As a result, light incident at a large angle relative to the central axis C1 onto one end face of the transmitting member 7 does not reach the other end face of the transmitting member 7 and will not exit from the other end face of the transmitting member 7. In other words, the light emitted from the transmitting member 7 is light whose incident angle at the side face of the transmitting member 7 is above the critical angle.

[0055] The amount of light received in sensor element 3 when the central axis C1 of component 7 is offset from the optical axis AX1 of lens body 5 is less than the amount of light received in sensor element 3 when the central axis C1 of component 7 is aligned with the optical axis AX1 of lens body 5. For high-precision reading of the object D, it is preferable that the offset between the central axis C1 of component 7 and the optical axis AX1 of lens body 5 is within the range of light received in sensor element 3 that is necessary to read information about the object D. Furthermore, the central axis C1 of at least one of the components 7 is preferably aligned with the optical axis AX1 of the corresponding lens body 5.

[0056] As described above, the optical component 1 of the image reading device 2 in Embodiment 1 includes a plurality of lens bodies 5 and a plurality of transmission components 7 corresponding to the lens bodies 5. The optical axis AX1 of the lens body 5 and the central axis C1 of the transmission component 7 corresponding to the lens body 5 are offset at least in the sub-scanning direction, so that the end face of each lens body 5 faces only the end face of the corresponding transmission component 7.

[0057] The cross-sectional shape of the lens body 5 in the plane perpendicular to the optical axis is such that the length of the main scanning direction at the position offset in the sub-scanning direction from the position passing through the optical axis is shorter than the length of the main scanning direction at the position passing through the optical axis. The cross-sectional shape of the transmitting component 7 in the plane perpendicular to the optical axis is such that the length of the main scanning direction at the position offset in the sub-scanning direction from the position passing through the central axis is shorter than the length of the main scanning direction at the position passing through the central axis. The transmitting component 7 is offset relative to the corresponding lens body 5 at least in the sub-scanning direction, so that the end face of the lens body 5 does not face more than two end faces of the transmitting components 7, and the end face of the lens body 5 faces only the end face of the corresponding transmitting component 7.

[0058] Furthermore, the transmitting component 7 has a reflection suppression component 72 formed on its side. Therefore, even if there is an error in the arrangement position of at least one of the lens body 5 and the transmitting component 7, the end face of each transmitting component 7 will not face the end faces of the plurality of lens bodies 5, and the light path of the light emitted from the mutually adjacent lens bodies 5 is separated. As a result, an optical component 1 and an image reading device 2 that suppress the overlap of images formed by the lens body 5 are obtained.

[0059] (Implementation Method 2)

[0060] The arrangement of the lens body 5 and the transmission component 7 is not limited to the examples described above. Focusing on the differences from Embodiment 1, Embodiment 2 will describe the optical component 1, which has the lens body 5 and the transmission component 7 arranged in a different manner than in Embodiment 1, and the image reading device 2, which has the optical component 1.

[0061] For example, when viewed in the positive Z-axis direction Figure 8 And the diagram of lens array 6 Figure 9 As shown, in the image reading device 2 of Embodiment 2, the optical component 1 includes a plurality of lens bodies 5 arranged at intervals from each other, and a plurality of transmitting components 7 arranged at intervals from each other. For example, the lens bodies 5 are arranged at equal intervals, and the transmitting components 7 are arranged at unequal intervals. Therefore, in Figure 8 In the middle, the central axis C1 of the left-hand transmission component 7 is aligned with the optical axis AX1 of the corresponding lens body 5, but the central axis C1 of the other transmission components 7 is offset from the optical axis AX1 of the corresponding lens body 5.

[0062] In the image reading device 2 of Embodiment 2, similarly to Embodiment 1, each optical axis AX1 of the lens body 5 is offset from the central axis C1 of the transmission component 7 corresponding to the lens body 5 at least in the sub-scanning direction.

[0063] exist Figure 10 A comparative example is shown where the lens body and the transmitting component are not offset in the sub-scanning direction. Figure 10The structure of the image reading device 90 shown is the same as that of the image reading device 2 in Embodiment 2, but it differs from the image reading device 2 in that the plurality of lens bodies 93 and the plurality of transmission members 94 are not offset in the Y-axis direction. Figure 10 This is a diagram showing the lens array of the image reading device 90 viewed along the positive Z-axis. Figure 10 In the diagram, solid lines represent the shape of the lens body 93, and dashed lines represent the shape of the transmitting component 94. Multiple lens bodies 93 are arranged at intervals along the main scanning direction. Multiple transmitting components 94 are arranged at intervals along the main scanning direction. The diameter of the lens body 93 is the same as the diameter of the transmitting component 94, and each has a cylindrical shape.

[0064] Due to errors in the arrangement of the transmitting elements 94, the central axis of each transmitting element 94 sometimes deviates from the optical axis of each lens body 93. As a result, for example, in... Figure 10 In the middle, the end faces of the transmitting components 94 at both ends are respectively aligned with the end faces of the corresponding lens bodies 93, but... Figure 10 Two transmitting elements 94, located at the center in the X-axis direction, abut against the end face of the corresponding lens body 93 and the end face of other lens bodies 93 adjacent to the lens body 93, respectively. Therefore, light emitted from two adjacent lens bodies 93 enters a transmitting element 94, resulting in an overlap of images formed by the two adjacent lens bodies 93.

[0065] like Figure 10 As shown, the following describes the structure in which the end face of a transmission member 94 is opposed to the end faces of a plurality of lens bodies 93.

[0066] like Figure 8 as well as Figure 9 As shown, errors sometimes occur in the arrangement position of at least one of the lens body 5 and the transmitting member 7. In embodiment 2, as... Figure 8 as well as Figure 9 As shown, on the plane perpendicular to the optical axis AX1 of the lens body 5, that is, the XY plane, that is, on the plane perpendicular to the optical axis, the midpoint L3 of the line segment connecting two adjacent lens bodies 5 with the shortest distance and the midpoint L4 of the line segment connecting the two adjacent lens bodies 5 and the two adjacent transmission components 7 with the shortest distance are offset at least in the sub-scanning direction.

[0067] As described above, each optical axis AX1 of the lens body 5 is offset from the central axis C1 of the transmitting component 7 corresponding to the lens body 5 at least in the sub-scanning direction, thereby, as Figure 9 As shown, the end face of each transmitting component 7 is not opposite to the end faces of the multiple lens bodies 5, but rather opposite to the end face of the corresponding lens body 5.

[0068] As described above, the optical component 1 of the image reading device 2 in Embodiment 2 includes a plurality of lens bodies 5 arranged at intervals from each other and a plurality of transmission components 7 arranged at intervals from each other, each corresponding to a lens body 5. The optical axis AX1 of the lens body 5 is offset from the central axis C1 of the transmission component 7 corresponding to the lens body 5 at least in the sub-scanning direction. Furthermore, the transmission component 7 has a reflection suppression component 72 formed on its side. Therefore, even if there is an error in the arrangement position of at least one of the lens bodies 5 and the transmission component 7, the end face of each transmission component 7 will not face the end face of the plurality of lens bodies 5, and the light path of the light emitted from the adjacent lens bodies 5 is separated. As a result, an optical component 1 and an image reading device 2 that suppress the overlap of images formed by the lens bodies 5 are obtained.

[0069] This disclosure is not limited to the examples of the embodiments described above. The arrangement of the constituent elements of the optical component 1 is not limited to the examples described above. Figure 11 As shown, the lens array 6 and the transmission component array 8 can also be arranged at intervals along the Z-axis and held in the frame 12.

[0070] The component array 8 can also be positioned closer to the object D being read than the lens array 6. More specifically, as... Figure 12 As shown, the optical component 1 may also include: a transmission component array 8 having a plurality of transmission components 7 that allow light incident from the object being read D onto one end face to exit from the other end face; and a lens array having a plurality of lens bodies 5 that converge light emitted from the other end face of the transmission components 7 and image it onto each sensor element 3.

[0071] exist Figure 12 In the example, the end face of the other end of the transmitting component 7 in the transmitting component array 8 abuts against the end face of the lens body 5 in the lens array 6, but the transmitting component 7 and the lens body 5 can also be as follows: Figure 13 They are arranged at intervals as shown.

[0072] The arrangement of sensor element 3 is not limited to the example above. As an example, the arrangement spacing of sensor element 3 in the X-axis direction can be the same as or different from the arrangement spacing of lens body 5 in the X-axis direction.

[0073] The arrangement of the lens body 5 and the transmission component 7 is not limited to the examples described above. Alternatively, the lens body 5 can be arranged at unequal intervals, and the transmission component 7 can be arranged at equal intervals.

[0074] The shapes of the lens body 5 and the transmitting member 7 are not limited to the examples described above. As an example, the transmitting member 7 may also have a cylindrical shape with a diameter larger than that of the lens body 5. In this case, multiple transmitting members 7 are arranged in abutting position, and multiple lens bodies 5 are arranged at intervals.

[0075] As another example, the lens body 5 and the transmitting component 7 can also be cylindrical. Specifically, at least one of the lens body 5 and the transmitting component 7 can also be formed from a cylinder with a cross-sectional shape of ellipse, polygon, or a shape consisting of a combination of curves and straight lines in the XY plane, i.e., the plane perpendicular to the optical axis. More specifically, the cross-sectional shape of the lens body 5 in the plane perpendicular to the optical axis can be such that the length of the main scanning direction at a position offset in the sub-scanning direction from the position along the optical axis is shorter than the length of the main scanning direction at the position along the optical axis. The cross-sectional shape of the transmitting component 7 in the plane perpendicular to the optical axis can be such that the length of the main scanning direction at a position offset in the sub-scanning direction from the position along the central axis is shorter than the length of the main scanning direction at the position along the central axis. The cross-sectional shapes of the lens body 5 and the transmitting component 7 can also be such that the length of the main scanning direction decreases as it approaches the end of the sub-scanning direction. The cross-sectional shapes of the lens body 5 and the transmitting component 7 can also have portions where the length of the main scanning direction is the same even if the positions of the sub-scanning directions are different.

[0076] The material of the light-transmitting component 7 is not limited to the examples described above. The light-transmitting component 7 can be formed of any component that allows light emitted from the light source 9 and used to read the object D to pass through. For example, if the light source 9 emits light different from visible light such as infrared or ultraviolet light, the light-transmitting component 7 can be formed of materials such as germanium, acrylic resin, or glass.

[0077] The material of the reflection suppression component 72 is not limited to the examples described above. The reflection suppression component 72 can be formed from any component that suppresses the reflection of light emitted from the light source 9 and used to read the object D.

[0078] In one implementation, the object to be read, D, moves relative to the fixed image reading device 2. However, the image reading device 2 can also move relative to the fixed object to be read, D, thereby reading information about the object to be read. The sub-scanning direction of the object to be read, i.e., the transport direction, can be achieved by transporting the object to be read, D itself, or by moving the image reading device 2.

[0079] The position of the light source 9 is not limited to the examples described above. For example, the image reading device 2 may also have a light source 9 located on the positive Z-axis side of the transmissive plate 10. In this case, the object D to be read can be transported between the light source 9 and the transmissive plate 10.

[0080] The light source 9 may also be located outside the image reading device 2. Specifically, it may be configured such that the light source 9 is located outside the frame 12 in either the case where the reflected light reflected by the object being read D is converged by the optical component 1 or the transmitted light passing through the object being read D is converged by the optical component 1.

[0081] The light emitted by the light source 9 passes through the light-transmitting plate 10, and the transmitted light is not limited to visible light. The light-transmitting plate 10 can also be formed of a component that allows infrared or ultraviolet light to pass through. Even if it is formed of a component that does not transmit visible light, it can still be used as the light-transmitting plate 10 as long as the light emitted by the light source 9 passes through. Unless it is necessary to form a transport surface for the object D to be read, the light-transmitting plate 10 can also be installed in the image reading device 2, specifically, the frame 12.

[0082] The structure of the light source 9 is not limited to the example described above. As an example, it can also have multiple LEDs (Light Emitting Diodes) and an LED substrate extending along the main scanning direction and on which each LED is formed. In this case, the multiple LEDs can be arranged in an array along the main scanning direction. Figure 1 In the middle, two light sources 9 are configured with optical components 1 separated by optical components 1, but one light source 9 can also be configured.

[0083] The location of the sensor substrate 11 is not limited to the example above. The sensor array 4 located on the sensor substrate 11 can be positioned arbitrarily to receive light converged by the lens array 6.

[0084] In this embodiment, a cylindrical refractive index distribution lens is used as the lens body 5, but the lens body 5 can be any type of lens for an upright equal-magnification optical system. As an example, a microlens can also be used as the lens body 5.

[0085] The construction of the light-transmitting component 7 is not limited to the examples described above; it can be arbitrary as long as light incident from one end face can exit from the other end face. As an example, the light-transmitting component 7 may also have a cylindrical shape with a through hole extending along the central axis C1. In other words, the light-transmitting component 7 may also have a cylindrical shape.

[0086] Various embodiments and modifications can be implemented without departing from the broad spirit and scope of this disclosure. Furthermore, the above-described embodiments are for illustrative purposes and do not limit the scope of this disclosure. That is, the scope of this disclosure is indicated by the claims, not by the embodiments. Moreover, various modifications applied within the scope of the claims and their equivalents are considered to be within the scope of this disclosure.

[0087] This application is based on Japanese Patent Application No. 2021-96276, filed on June 9, 2021. The entire description, claims, and drawings of Japanese Patent Application No. 2021-96276 are incorporated herein by reference.

[0088] Explanation of reference numerals in the attached figures

[0089] D... Object to be read; 1... Optical component; 2, 90... Image reading device; 3... Sensor element; 4... Sensor array; 5, 91, 93... Lens body; 6... Lens array; 56... Side plate; 7, 92, 94... Transmitting component; 71... Cylindrical component; 72... Reflection suppression component; 8... Transmitting component array; 78... Side plate; 9... Light source; 10... Transmitting plate; 11... Sensor substrate; 12... Frame; 12a, 12b... Opening; AX1... Optical axis; C1... Central axis; L1, L2... Contact point; L3, L4... Midpoint.

Claims

1. An optical component, characterized in that, have: A lens array having multiple lenses arranged in a row along the main scanning direction to converge light from the object being read; and Multiple transmitting elements, formed of components with the same refractive index, are respectively positioned closer to the object being read than the corresponding lens body or farther away from the object being read than the lens body. They have a cylindrical shape extending along the optical axis of the lens body, allowing light incident from one end face to exit from the other end face. The cross-sectional shape of the lens body on the plane perpendicular to the optical axis, i.e., the plane perpendicular to the optical axis, is such that the length of the main scanning direction at a position offset from the optical axis in the sub-scanning direction intersecting the main scanning direction is shorter than the length of the main scanning direction at the position passing through the optical axis. The cross-sectional shape of the transmitting component on the plane perpendicular to the optical axis is such that the length of the main scanning direction at a position offset from the central axis in the sub-scanning direction is shorter than the length of the main scanning direction at the position of the central axis of the transmitting component. The optical axis of each lens body is offset from the central axis of the transmitting element corresponding to that lens body at least in the sub-scanning direction by a factor greater than the manufacturing error or arrangement error of the transmitting element, so that the end face of the transmitting element does not face the end faces of the plurality of lens bodies but only faces the end face of the corresponding lens body.

2. The optical component according to claim 1, characterized in that, For the plurality of transmitting elements, the central axis of each transmitting element is offset from the optical axis of the lens body corresponding to that transmitting element in the sub-scanning direction by a factor greater than the manufacturing error or the error in the arrangement position of the transmitting element, and is arranged in a row along the main scanning direction.

3. The optical component according to claim 1 or 2, characterized in that, The diameter of the lens body is the same as the diameter of the transmitting component, and both have a cylindrical shape.

4. The optical component according to claim 1 or 2, characterized in that, At least a portion of the surface of the lens body facing the transmitting member is opposite to the surface of the transmitting member facing the lens body in the direction of extension of the optical axis.

5. The optical component according to claim 1 or 2, characterized in that, At least one of the plurality of lenses and the plurality of transmitting elements is arranged in a state of mutual contact.

6. The optical component according to claim 1 or 2, characterized in that, The plurality of lenses are arranged in a state of mutual contact. The plurality of transparent components are arranged in a state of mutual contact. On the plane perpendicular to the optical axis, the contact points of the two lenses that abut against each other, and the contact points of the two transmitting elements that correspond to and abut against the two lenses that abut against each other, are offset in at least the sub-scanning direction by a factor greater than the manufacturing error or the error in the arrangement position of the transmitting elements.

7. The optical component according to claim 6, characterized in that, On the plane perpendicular to the optical axis, the contact points of the two lenses that abut against each other, and the contact points of the two transmitting components that correspond to and abut against the two lenses that abut against each other, are offset in the sub-scanning direction and the main scanning direction by a distance greater than the manufacturing error or arrangement error of the transmitting components.

8. The optical component according to claim 1 or 2, characterized in that, The plurality of lenses are arranged at intervals between each other. The plurality of transparent components are arranged at intervals between each other. On the plane perpendicular to the optical axis, the midpoints of the line segments connecting two adjacent lens bodies with the shortest distance, and the midpoints of the line segments connecting two adjacent and corresponding transmission components with the shortest distance, are offset in at least the sub-scanning direction by a distance greater than the manufacturing error or arrangement error of the transmission components.

9. The optical component according to claim 1 or 2, characterized in that, The through-hole has a cylindrical shape with a through hole extending along the central axis.

10. An image reading device, characterized in that, have: The optical component according to any one of claims 1 to 9; and A sensor array having multiple sensor elements arranged according to each of the lens bodies of the lens array of the optical component, and receiving light focused by the lens bodies.

Images