JP4271841B2 - Lens array unit and optical apparatus having the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to an optical apparatus such as an image reading apparatus, and a lens array unit used for forming a desired object image by being incorporated in the optical apparatus.
[0002]
[Prior art]
  An image reading apparatus incorporated in a facsimile apparatus or a scanner apparatus often reads an image of an original at an equal magnification by using a plurality of light receiving elements arranged in a line. In this case, it is necessary to form an image of the original on the plurality of light receiving elements at an equal magnification by using a lens array including a plurality of imaging lenses. Therefore, conventionally, there is a lens array 9 as shown in FIGS.
[0003]
  The lens array 9 has a configuration in which a plurality of rod lenses 91 are arranged in a line and are held by a resin holder 90. Each rod lens 91 has a cylindrical shape in which a pair of lens surfaces 91a and 91b are both flat. However, each rod lens 91 has a unique optical characteristic, and is configured such that its refractive index varies depending on the distance from the axis. As a result, as shown in FIG. 18, the light traveling in each rod lens 91 follows a meandering path, and an erecting equal-magnification image (a ′ → b ′) of the object (a → b) is obtained. can get.
[0004]
  In order to manufacture the lens array 9, first, a plurality of rod lenses 91 are manufactured. Next, by using an insert molding technique, the holder portion 90 is resin-molded in such a manner that the plurality of rod lenses 91 are embedded therein.
[0005]
[Problems to be solved by the invention]
  However, since the rod lens 91 has unique optical characteristics as described above, its manufacture is not easy. It is difficult for a manufacturer that does not have special equipment for manufacturing the rod lens 91 to manufacture the lens, and this increases the manufacturing cost of the lens array 9. Further, conventionally, since the manufacturing operation of the plurality of rod lenses 91 and the molding operation of the holder part 90 are performed separately, the production efficiency of the lens array 9 is also poor. As a result, the manufacturing cost of the lens array 9 was further increased.
[0006]
  The present invention has been conceived under such circumstances, and a lens array unit excellent in optical performance that can be manufactured more efficiently and inexpensively than a conventional lens array. The issue is to provide. Another object of the present invention is to provide an optical device incorporating such a lens array unit.
[0007]
DISCLOSURE OF THE INVENTION
  In order to solve the above problems, the present invention takes the following technical means.
[0008]
  The lens array unit provided by the present invention has a plurality of first lenses as convex lenses each having a first lens surface and a second lens surface, and a first holder portion that holds the plurality of first lenses. A first lens array in which the first holder part and the first lens are integrally formed of a translucent resin, a plurality of second lenses as convex lenses each having a third and a fourth lens surface, and these A second holder portion for holding a plurality of second lenses is included, the second holder portion and the second lens are integrally formed of a light-transmitting resin, and the third lens surface is the second lens portion. A second lens array superimposed on the first lens array so as to face the lens surface;, DoubleThe first lens array has a plurality of through holes, and the plurality of through holes are arranged in front of the first lens surfaces.HeavyA plurality of light shielding members that are joined together, and each of the first lens surfaces has a diameter larger than that of each through hole of the light shielding member.On the other hand, the plurality of light shielding members have a structure in which at least a part of the plurality of light shielding members overlap with each other in the thickness direction at the joint portion thereof, in the row direction of the plurality of first lenses. It is attached to the first lens array so as to be connected and aligned.It is characterized by that.
[0009]
  In the lens array unit having such a configuration, the following effects can be obtained.
[0010]
  First, each of the first and second lenses is a convex lens, and unlike a conventional rod lens, it is not necessary to be configured to have a different refractive index inside the lens. In the present invention, the lenses of the first and second lens arrays and the holder portion for holding the lenses can be easily manufactured by a normal resin molding method using a mold. On the other hand, the said light shielding member has a form provided with the several through-hole, This light shielding member can also be manufactured easily. Therefore, the lens array unit according to the present invention has high production efficiency and can be manufactured at a lower cost than the conventional lens array.
[0011]
  Second, since the lens array unit according to the present invention combines the first and second lens arrays as the convex lens array, optical characteristics that cannot be obtained by using only one convex lens array can be obtained. Thus, as will be described later, for example, an erecting equal-magnification image can be formed.
[0012]
  Third, when forming an image of the imaging object, if the lens array unit according to the present invention is used so that the light shielding member faces the imaging object, each through hole of the light shielding member is used. Only the light that has passed through the first lens surface can be incident on the first lens surfaces, and then the light can travel into the first and second lenses. That is, in the present invention, the light traveling from the imaging target toward the first and second lenses can be narrowed down in advance by the light shielding member. In this way, the light traveling from the imaging object can be prevented from passing through the holder portions of the first and second lens arrays, and unnecessary light reaches the imaging area of the image. You can avoid it. Further, if each through hole of the light shielding member has an appropriate depth, light having a large inclination angle with respect to the axes of the first and second lenses can be shielded by the light shielding member. Only light having a small tilt angle within a predetermined angle range with respect to the axes of the first and second lenses can be incident on the first lens surface. Therefore, a phenomenon in which light that has traveled from the first lens surface into the first lens travels into the first lens adjacent to the first lens or travels into the second lens in the positional relationship next to the first lens ( It is possible to appropriately prevent or suppress (crosstalk of light). Therefore, a clear image is obtained. Fourth, even if the centers of the first lens surfaces and the through holes are misaligned, the first lenses can be used as long as the amount of misalignment is within a certain size range. It is possible to maintain the state in which each of the through holes is arranged in front of the surface, and to perform proper image formation. Fifth,Compared with the case where only one light shielding member is used, the length of each of the plurality of light shielding members can be shortened, so that it is possible to make warpage deformation and the like less likely to occur in each of the light shielding members. Therefore, for example, each light shielding member can be prevented from being lifted from the first lens array without setting each of the light shielding members to be stretchable and then setting it to the extended state. In this case, the joint portion of the plurality of light shielding members has a structure that does not transmit light in the thickness direction of the light shielding member. Therefore, it is possible to appropriately prevent light unnecessary for image formation from passing through the joint portion and traveling into the first lens array.
[0013]
  In a preferred embodiment of the present invention, the first and second lens arrays can form an erecting equal-magnification image.
[0014]
  According to such a configuration, the lens array unit according to the present invention can be suitably used as an alternative to a conventional rod lens array capable of forming an erecting equal-magnification image.
[0015]
[0016]
[0017]
[0018]
[0019]
  In another preferred embodiment of the present invention, the light shielding member and the first lens array are provided with at least a pair of concave portions and convex portions, and the fitting of the concave portions and the convex portions results in the above-mentioned The light shielding member is assembled to the first lens array.
[0020]
  According to such a configuration, the operation of accurately positioning and combining the light shielding member and the first lens array with each other is facilitated.
[0021]
[0022]
[0023]
[0024]
[0025]
[0026]
[0027]
  In another preferred embodiment of the present invention, each of the plurality of light shielding members has the same shape and size.
[0028]
  According to such a configuration, it is only necessary to manufacture one type of the plurality of light shielding members, which is suitable for reducing the manufacturing cost.
[0029]
  In another preferred embodiment of the present invention, each of the first lens surfaces is convex, and at least a part of the first lens surface is fitted into each through hole of the light shielding member.
[0030]
  According to such a configuration, alignment between the first lens surfaces and the through holes is facilitated. In addition, it is possible to make it difficult for these positional shifts to occur.
[0031]
[0032]
[0033]
[0034]
[0035]
  An optical device provided by the present invention is an optical device provided with an imaging means for focusing the light traveling from the object to form an image of the object at a predetermined position, As the imaging means, the lens array unit according to the present invention is used.
[0036]
  According to such a configuration, the same effect as that seen in the lens array unit according to the present invention can be expected.
[0037]
  In a preferred embodiment of the present invention, a light source for illuminating the document and a plurality of light receiving elements having a photoelectric conversion function are further provided, and light reflected by the document is transmitted by the lens array unit. By focusing, the image of the original is formed on the plurality of light receiving elements.
[0038]
  According to such a configuration, the image of the original can be appropriately read by the plurality of light receiving elements.
[0039]
  Other features and advantages of the present invention will become more apparent from the following description of embodiments of the invention.
[0040]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, a preferred embodiment of the present invention will be specifically described with reference to the drawings.
[0041]
  1 to 5 show the lens array unit according to the present invention.referenceAn example is shown. As best seen in FIGS. 1 and 2,ThisThe lens array unit U1 includes a first lens array 1, a second lens array 2, and a light shielding member 3.
[0042]
  The first lens array 1 includes a plurality of first lenses 11 arranged in a straight line at regular intervals, and a first holder portion 10 formed integrally with the plurality of first lenses 11. An array body 1a is provided. The basic structure of the second lens array 2 is the same as that of the first lens array 1, and a plurality of second lenses 21 arranged in a straight line at regular intervals, and the plurality of second lenses. 21 includes a lens array body 2 a that includes a second holder portion 20 that is integrally connected to 21. Each of the lens array main bodies 1a and 2a has a block shape extending in a certain direction, and is made of a synthetic resin having translucency. As the synthetic resin having translucency, for example, PMMA (polymethyl methacrylate (methacrylic resin)) or PC (polycarbonate) is used.
[0043]
  The first lens 11 is a biconvex lens having first and second lens surfaces 11a and 11b as convex curved surfaces spaced in the direction of the axis C. The second lens 21 is a biconvex lens having third and fourth lens surfaces 21a and 21b as convex curved surfaces spaced in the direction of the axis C. As will be described later, the first, second, third, and fourth lens surfaces 11a, 11b, 21a, and 21b have such a curvature that an erecting equal-magnification image can be formed. Each lens surface described above may be either spherical or aspherical. If each of the lens surfaces is a spherical surface, its manufacture becomes easy. On the other hand, aberrations can be reduced by making each lens surface an aspherical surface. Note that the first and second lenses 11 and 12 are not necessarily biconvex lenses. For example, an erecting equal-magnification image can be formed even when the second lens surface 11b is planar. The arrangement pitch of each of the first and second lenses 11 is, for example, about 1 mm. Each of the lens surfaces 11a, 11b, 21a, and 21b has a diameter of, for example, about 0.6 to 1.0 mm. However, in the present embodiment, the second lens surface 11b and the third lens surface 21a are basically directed from the first lens surface 11a to the fourth lens surface 21b except that they have substantially the same diameter. Accordingly, the diameter of the lens surface gradually increases, and the fourth lens surface 21b is sized such that the fourth lens surfaces 21b adjacent to each other are in contact with each other.
[0044]
  Two pairs of concave portions 13 and convex portions 23 having stepped portions 23a are provided at both longitudinal ends of the surfaces 10b and 20a of the first and second holder portions 10 and 20 facing each other. The first and second lens arrays 1 and 2 are superimposed and assembled with each other by fitting the concave portion 13 and the tip portion of the convex portion 23, and the first and second lenses 11 and 12 are respectively assembled. The axes C are aligned. A step portion 23a is in contact with the surface 10b of the first holder portion 10, and thereby the interval between the second lens surface 11b and the third lens surface 21a is defined. At least one pair of convex portions 14 and concave portions 24 are provided in the longitudinal direction intermediate portions of the surfaces 10b and 20a so as to avoid the first and second lenses 11 and 21 (see FIG. 4). The first and second lens arrays 1 and 2 are positioned with each other by the fitting action of the convex portion 14 and the concave portion 24, and the distance between the second lens surface 11b and the third lens surface 21a is set. It is prescribed.
[0045]
  As shown in FIG. 2, the light-shielding member 3 is in the form of a block or sheet extending in a certain direction, like the first and second lens arrays 1 and 2, and having an appropriate thickness. Yes. However, the light shielding member 3 is made of, for example, black ABS resin having light shielding properties. The light shielding member 3 is provided with a plurality of through holes 30 corresponding to the first and second lenses 11 and 21 arranged in a linear row. The inner wall surface 30a of each through hole 30 is also black.
[0046]
  On the surface (back surface) 31 b of the light shielding member 3, a plurality of concave portions 35 are provided at intervals in the longitudinal direction of the light shielding member 3. On the other hand, a plurality of convex portions 15 are provided on the surface 10 a of the first holder portion 10 of the first lens array 1. The light shielding member 3 is overlapped so as to contact or approach the surface 10a of the first holder portion 10 of the first lens array 1 by fitting the plurality of concave portions 35 and the convex portions 15 (see FIG. 3). Has been attached. Thereby, each through-hole 30 of the light shielding member 3 is located in front of each first lens surface 11a and is open.
[0047]
  However, since the light shielding member 3 is made of ABS resin and has a relatively small thickness, the light shielding member 3 has elasticity in the longitudinal direction, and the light shielding member 3 is in a state of being appropriately stretched in the longitudinal direction. And attached to the first lens array 1. The fitting between the plurality of concave portions 35 and the convex portions 15 also serves to maintain the extended state of the light shielding member 3. When the light shielding member 3 is extended as described above, the arrangement pitch of the plurality of through holes 30 becomes longer than that before the extension. However, the amount of change is practically a negligible dimension. Therefore, the arrangement pitch of the plurality of through holes 30 can be the same as the arrangement pitch of the first lenses 11. Of course, the arrangement pitch of the plurality of through-holes 30 may be slightly shorter than the arrangement pitch of the first lenses 11 in advance, and when the light shielding member 3 is extended, the arrangement pitch may be matched. it can.
[0048]
  The diameter D2 of each through hole 30 is smaller than the diameter D1 of each first lens surface 11a. Further, a part of each first lens surface 11 a is in a state of being fitted into each through hole 30. 2 and 5, at least one recess 36 is provided on one side edge of the surface (front surface) 31 a of the light shielding member 3. Further, upward convex portions 37 are provided at both longitudinal ends of the light shielding member 3. These concave portions 36 and convex portions 37 are portions used for positioning the light shielding member 3 in the optical device A described later.
[0049]
  The first and second lens arrays 1 and 2 and the light shielding member 3 having the above-described configuration can be manufactured by the following manufacturing method, for example.
[0050]
  First, in order to manufacture the first lens array 1, as shown in FIG. 6, the cavity formed by the upper mold 6a and the lower mold 6b of the mold 6 is filled with a transparent resin and cured, and then the mold is removed. I do. The upper mold 6a and the lower mold 6b are formed with a plurality of recesses 11a ′ and 11b ′ corresponding to the first and second lens surfaces 11a and 11b, and a protrusion 13 ′ corresponding to the plurality of recesses 13 and the like. . By the resin molding step described above, the lens array body 1a can be molded, and the first lens array 1 can be easily obtained. When many first lens arrays 1 are produced, for example, after forming a plate-shaped or sheet-shaped resin molded product having the same form as the lens array main body 1a is assembled, the resin molded product is cut. A technique of dividing into a plurality of lens array bodies 1a can also be adopted. The second lens array 2 can also be easily manufactured by the same method as described above. The first and second lens arrays 1 and 2 are formed by forming a resin molded product having the same form as the two lens array main bodies 1a and 1b arranged side by side and then dividing the resin molded product. If the lens is manufactured, the resin molding conditions can be made the same, which is suitable for making the arrangement pitches of the first and second lenses 11 and 21 the same.
[0051]
  The light shielding member 3 can be manufactured by a resin molding process using a mold, similarly to the first and second lens arrays 1 and 2. Each through-hole 30 can be formed by the resin molding step, but can also be formed by subjecting a resin molded product that is a prototype of the light shielding member 3 to machining or laser processing.
[0052]
  The lens array unit U1 can be assembled by stacking and assembling the first and second lens arrays 1 and 2 together and attaching the light shielding member 3 to the first lens array 1 in an overlapping manner. Assembly of the first and second lens arrays 1 and 2 can be easily performed by fitting the concave portions 13 and the convex portions 14 to the convex portions 23 and the concave portions 24, respectively. The light shielding member 3 can be easily attached to the first lens array 1 by fitting the convex portions 15 and the concave portions 35 to each other. Therefore, as for the manufacturing cost of the lens array unit U1 of the present embodiment, a conventional rod lens manufactured by manufacturing a large number of rod lenses having special optical characteristics and then incorporating the large number of rod lenses into the holder portion. Compared to an array, it can be considerably cheaper.
[0053]
  Next, an example of forming an image using the lens array unit U1 having the above configuration will be described with reference to FIG.
[0054]
  In the optical system shown in FIG. 7, when light starting from the start point S on the front surface (upper side of the drawing) of the light shielding member 3 passes through each through-hole 30 of the light shielding member 3, this light is then transmitted to the first lens 11 and the second lens. After sequentially passing through the lens 21, it reaches the imaging point R behind the second lens array 2. In this case, the first and second lenses 11 and 21 arranged on the common axis C refract light, so that a phenomenon equivalent to the light meandering phenomenon seen in the conventional rod lens described above can be obtained. As a result, an erecting equal-magnification image (a ′ → b ′ → c ′) of the object (a → b → c) at the starting point S can be formed at the imaging point R. In other words, in this optical system, the first lens surface 11a of each first lens 11 forms an inverted reduced image of the object (a → b → c), and the inverted reduced image is at a later stage. As a result of being magnified and inverted by the second, third and fourth lens surfaces 11b, 21a and 21b, an erecting equal-magnification image of the object is formed at the imaging point R.
[0055]
  In the optical system, since the light shielding member 3 is provided in front of the first lens array 1 and the surface 10a of the first holder portion 10 is covered by the light shielding member 3, the light traveling from the starting point S is obtained. Can be prevented from proceeding into the first holder part 10. Therefore, the first and second holder portions 10 and 20 are made of a synthetic resin having translucency, so that the light from the starting point S does not pass through them and reach the imaging point R. be able to.
[0056]
  Each through hole 30 of the light shielding member 3 plays a role of narrowing light to be incident on each first lens surface 11a. Since each through hole 30 has an appropriate depth, for example, as indicated by reference numeral n1, a light beam traveling at a large inclination angle from the start point S to the axis C (a light beam having a large spread angle from the start point S). ), The light beam reaches the inner wall surface 30 a of the through hole 30 even if it travels into the through hole 30. Since the inner wall surface 30a is black, the light beam is absorbed and is not reflected toward the first lens surface 11a. Therefore, it is possible to allow only light rays having a small spread angle from the starting point S to enter each first lens surface 11a.
[0057]
  As a result, the light traveling from each first lens surface 11a into each first lens 11 does not travel in a direction that is far away from the axis C of the first lens 11. For this reason, the light that has traveled into one first lens 11 travels into the adjacent first lens 11 or the second lens 21 that is in the positional relationship therewith, and travels into one second lens 21. It is possible to appropriately prevent the transmitted light from traveling into the adjacent second lens 21 (light crosstalk between a plurality of lenses). As described above, in the above optical system, the light traveling in one first lens 11 is moved from the fourth lens surface 21b of the second lens 21 coaxially arranged with the first lens 11 to the imaging point R. Can be appropriately emitted. Therefore, a clear erecting equal-magnification image can be formed at the imaging point R. In particular, in the present embodiment, since each lens surface gradually increases in diameter as it goes from the first lens surface 11a to the fourth lens surface 21b, or has a configuration close thereto, the first lens. Even if the light that has passed through the surface 11a subsequently travels at a position slightly away from the axis C, this light appropriately passes through each of the second, third, and fourth lens surfaces 11b, 21a, and 21b, and at each of those points. Will be refracted. Therefore, the image formed at the image point R can be made clearer.
[0058]
  The light shielding member 3 is attached to the first lens array 1 in a state where the light shielding member 3 extends in the longitudinal direction. Therefore, the light shielding member 3 can be prevented from easily floating from the first lens array 1. Further, since the light shielding member 3 is positioned with respect to the first lens array 1 by the fitting action of the convex portions 15 and the concave portions 35 (see FIGS. 2 and 3), the light shielding member 3 is penetrated through the light shielding member 3. It is possible to prevent the holes 30 from being easily displaced with respect to the first lens surfaces 11a. Since a part of each first lens surface 11 a is fitted in the bottom of each through hole 30, the above displacement is further prevented.
[0059]
  However, in this lens array unit U1, even if the center deviation between each through hole 30 and each first lens surface 11a occurs, each first lens surface 11a has a larger diameter than each through hole 30. For this reason, if the amount of deviation is equal to or less than the predetermined amount, the entire area of each through hole 30 can be arranged in front of each first lens surface 11a. For example, if the diameters of the through-hole 30 and the first lens surface 11a are the same, the through-hole 30 and the first lens surface 11a are displaced only by their center being slightly displaced, and the through-hole 30 is Among the light that has passed, light that passes through the first holder portion 10 is generated. However, in this embodiment, it is possible to prevent such a phenomenon, and due to a slight misalignment between each through hole 30 and each first lens surface 11a, the optical property of the lens array unit U1 is reduced. There is no such thing as extreme deterioration in performance.
[0060]
  FIG. 8 shows an example of an optical device according to the present invention.
[0061]
  The optical device A shown in FIG. 1 includes a transparent plate 70, a synthetic resin case 71 that supports the transparent plate 70 on the upper surface portion, and a substrate 72 assembled to the bottom surface portion of the case 71. . On the surface of the substrate 72, a plurality of light sources 73 arranged in a row at intervals in the main scanning direction (a direction orthogonal to the paper surface), and a plurality of light sources 73 arranged in the same direction as the plurality of light sources 73 are arranged. A light receiving element 74 is arranged. Each light source 73 is configured using, for example, a light emitting diode. Each light receiving element 74 has a photoelectric conversion function, and when receiving light, outputs a signal (image signal) of an output level corresponding to the amount of received light.
[0062]
  Between the transparent plate 70 and each light receiving element 74, the above-described lens array unit U1 is disposed. In the lens array unit U1, the first and second lens arrays 1 and 2 are fitted in the concave grooves 75 provided in the case 71, so that the first and second lenses 11 and 21 are arranged in the main scanning direction. It is incorporated so as to extend. The case 71 is provided with projections 71 a corresponding to the respective recesses 36 of the light shielding member 3. The projections 71 a are engaged with the respective recesses 36, thereby positioning the light shielding member 3 with respect to the case 71 and shielding the light. The upward lifting of the member 3 is prevented. Further, the convex portions 37 at both ends in the longitudinal direction of the light shielding member 3 are in contact with the back surface (lower surface) of the transparent plate 70, and the transparent plate 70 also prevents the light shielding member 3 from being lifted upward. . Of the surface portion of the transparent plate 70, the portion facing each through-hole 30 and each first lens 11 is a line-shaped image reading region La.
[0063]
  The light emitted from each light source 73 is applied to the image reading region La via the light guide member 76 accommodated in the case 71. The light guide member 76 is made of, for example, transparent PMMA or PC, and has convex surfaces 76 a and 76 b for bringing light emitted from each light source 73 with a certain spread angle close to parallel rays. The light that has passed through these two convex surfaces 76a and 76b is totally reflected by the inclined surface 76c of the light guide member 76, so that it can be efficiently and intensively guided toward the image reading region La. It has become. However, the present invention is not limited to this, and the light emitted from each light source 73 can be converted into an image reading region without using the light guide member 76 or using a light guide member having a different form from the light guide member 76. You may guide to La. A platen roller 77 for conveying the original G is provided on the image reading area La.
[0064]
  In this optical apparatus A, the light emitted from each light source 73 is guided to the image reading area La and illuminates the document G. The light reflected by the document G travels toward the lens array unit U1. Then, due to the action described with reference to FIG. 7, an image for one line of the document G in the image reading area La is formed on the plurality of light receiving elements 74 at an equal magnification. Therefore, an image signal for one line corresponding to the image of the document G is output from the plurality of light receiving elements 74. Such a reading process is repeatedly executed a plurality of times in the process in which the document G is conveyed in the sub-scanning direction by the platen roller 77. In this optical apparatus A, the rod lens array of the prior art is not used as the image forming means for the document image, and the lens array unit U1 that can be manufactured at a lower cost than that is used. Therefore, the manufacturing cost of the optical device A is also low.
[0065]
  9 to 15 show the lens array unit according to the present invention.oneAn example is shown. In FIG. 9 and subsequent figures, the aboveReference exampleElements that are the same or similar to,same1 is attached.
[0066]
  The lens array unit U2 shown in FIGS. 9 and 10 has a configuration in which a plurality of light shielding members 3A are attached to the front surface of the first lens array 1. Each light shielding member 3A is shown in FIGS.In the reference exampleThe light shielding member 3 has substantially the same form as being divided into a plurality of portions in the longitudinal direction, and is formed to have a shorter overall length than the light shielding member 3. The material of each light shielding member 3A is, for example, a polystyrene-based synthetic resin including syndiotactic polystyrene. Each light shielding member 3A has a plurality of through holes 30 arranged in the longitudinal direction, and step portions 39a and 39b are formed at both ends in the longitudinal direction. The stepped portion 39a is offset from the upper part in the thickness direction of each light shielding member 3A, whereas the stepped portion 39b is positioned to be offset from the lower part in the thickness direction of each light shielding member 3A. Each of the plurality of light shielding members 3A is formed in the same shape and size.
[0067]
  The plurality of light shielding members 3 </ b> A are fitted to the convex portions 15 of the first lens array 1 by fitting the concave portions 35 of the back surface 31 b thereof (see FIG. 10), so that the plurality of light shielding members 3 </ b> A are arranged in the longitudinal direction of the first lens array 1. It is attached to the first lens array 1 so as to be connected in the direction. As clearly shown in FIG. 9, the joint portion Na between the plurality of light shielding members 3A is composed of a step portion 39a of one light shielding member 3A and a step portion 39b of the other light shielding member 3A. 3A is overlapped in the thickness direction (vertical direction in the drawing).
[0068]
  In this lens array unit U2, light unnecessary for image formation can be blocked and absorbed by the plurality of light blocking members 3A.According to reference examplesAs with the lens array unit U1, a clear erecting equal-magnification image can be formed. Since the step portions 39a and 39b overlap each other at the joint portion Na between the light shielding members 3A, there is a gap in the joint portion Na, and light from the front is in the gap. Even if the light travels, this light can be prevented from traveling toward the first lens array 1 as it is. Therefore, it is possible to reliably prevent the light from being improperly incident on the first lens array 1 through the joint portions Na of the plurality of light shielding members 3A.
[0069]
  As described above, each of the plurality of light shielding members 3 </ b> A has a shorter overall length than the total length of the light shielding member 3 of the previous embodiment. Therefore, the light shielding members 3A can be prevented from unreasonably floating from the first lens array 1 without being assembled to the first lens array 1 in an expanded state. For this reason, each light shielding member 3A does not need to have elasticity, and as a molding material for each light shielding member 3A, a resin having good fluidity can be used during molding. That is, a resin having high stretchability generally has poor fluidity at the time of mold molding. However, since each light shielding member 3A does not need to have stretchability, the material of each light shielding member 3A is as follows. For example, it is possible to use a resin having good fluidity, such as a polystyrene-based synthetic resin including the syndiotactic polystyrene described above, and the molding of each light shielding member 3A is facilitated. In addition, since each of the plurality of light shielding members 3A has the same shape and size, only one type of mold may be used for molding them, and their manufacture is easy.
[0070]
  Like the said embodiment, in this invention, it can be set as the structure which used multiple light-shielding members. In this case, the specific number of light shielding members is not particularly limited.
[0071]
  In the configuration shown in FIG. 11, the end faces 38a and 38b at the both ends in the longitudinal direction of the plurality of light shielding members 3A are inclined. In the joint portion Nb of the plurality of light shielding members 3A, the end surfaces 38a and 38a face each other, so that they overlap each other in the thickness direction of each light shielding member 3A. Even in such a configuration, when light travels from the front of the joint portion Nb, it is possible to prevent light from passing through the gap. As described above, in the present invention, as means for preventing light transmission at the joint portion of the plurality of light shielding members 3A, means for forming at least a part of the end surface of each light shielding member 3A in an inclined shape is used. You can also.
[0072]
  In the configuration shown in FIG. 12, a semicircular recess 30A is formed at each longitudinal end of each of the plurality of light shielding members 3A. When the two light shielding members 3A are connected to each other, one through hole 30 is formed by the pair of recesses 30A. Such a configuration is suitable when the arrangement pitch of the through holes 30 is small and the interval dimension s2 between the through holes 30 must be reduced. That is, in the light shielding member 3A having the configuration shown in FIG. 10, when the arrangement pitch of the through holes 30 is small, the edge of the through hole 30 (30 ′) located closest to the end in the longitudinal direction. The dimension s1 from the light shielding member 3A to the end face of the light shielding member 3A becomes very small, and it may be difficult to form such a thin portion. On the other hand, according to the configuration shown in FIG. 12, such a thin portion can be prevented from occurring, and the light shielding member 3A can be easily formed. Of course, even when the concave portion 30A is formed at the end portion of each light shielding member 3A, for example, step portions 39a and 39b are formed at the end portion so that light does not pass through the joint portion between the light shielding members 3A. Can be.
[0073]
  FIG.Shows a lens array unit U3 as another reference example. thisThe lens array unit U3 has a configuration in which the first and second lenses 11 and 21 are arranged in a plurality of narrow rows extending in a certain direction. The plurality of through holes 30 of the light shielding member 3 are also arranged in a plurality of rows corresponding to the first and second lenses 11 and 21.
[0074]
  In the lens array unit U3, a line-shaped image can be formed at an equal magnification, as in the lens array units U1 and U2. Further, in this lens array unit U3, the light that travels to the imaging point after passing through each of the lenses 11 and 21 is compared with that in which the first and second lenses 11 and 21 are provided in only one row. The amount can be increased. Therefore, it is preferable for brightening the formed image. The light shielding member 3 prevents light crosstalk between the lenses 11 adjacent to each other in the longitudinal direction of the lens array unit U3 or between the lenses 21, and also provides light between lenses adjacent to each other in the lateral direction of the lens array unit U3. Also prevents crosstalk.
[0075]
  FIG.Shows a lens array unit U4 as still another reference example. thisThe lens array unit U4 has a configuration in which each of the first and second lens arrays 1 and 2 is formed in a substantially plate shape, and each of the first and second lenses 11 and 21 is arranged in a matrix. Have. The plurality of through holes 30 of the light shielding member 3 are also arranged in a matrix corresponding to the first and second lenses 11 and 21.
[0076]
  In the lens array unit U4, it is possible to form an image of a planar region having a certain area at an erecting equal magnification. Therefore, for example, it is suitable for an application in which an image displayed on the screen of a liquid crystal display or other display device is formed at a predetermined position. The light blocking member 3 prevents crosstalk of light between adjacent lenses in the vertical direction or horizontal direction, which is the arrangement direction of the lenses 11 and 21, and also prevents crosstalk of light between adjacent lenses in the oblique direction. Play a role to prevent.
[0077]
[0078]
  FIG.Shows a lens array unit U5 as still another reference example. thisThe lens array unit U5 has a configuration in which a light shielding film 29a made of a black paint film is provided on the surface 20a of the second holder portion 20. Further, the surface 20 b of the second holder part 20 is provided with a recess 29 b that partitions the second lenses 21.
[0079]
  In the lens array unit U5, light crosstalk between the plurality of lenses 11 and 21 can be more reliably prevented. That is, in order to allow only light having a small inclination angle with respect to the axis C to enter each first lens surface 11a, each through-hole 30 of the light shielding member 3 is formed to have an appropriate depth. If it is necessary and the depth of each through-hole 30 is insufficient, light inclined at a large angle with respect to the axis C is incident on each first lens surface 11a. However,ThisIn such a lens array unit U5, such a situation occurs, and as indicated by reference numeral n2, a part of the light emitted from the second lens surface 11b travels toward the surface 20a of the second holder portion 20. However, this light is blocked by the light shielding film 29a. The surface defining the recess 29b can totally reflect the received light as indicated by reference numeral n3, and plays a role of preventing light crosstalk between the plurality of second lenses 21. Therefore, even if the depth of each through hole 30 of the light shielding member 3 is considered to be insufficient, the lens array unit U5 can effectively prevent crosstalk of light between the lenses, and is clear. It is possible to obtain a simple image.
[0080]
  In the present invention, as each through hole 30 of the light shielding member 3 is deepened, it is possible to increase the rate at which light having a small inclination angle with respect to the axis C is incident on the first lens surface 11a. By setting the depth to a certain depth, it is possible to prevent light crosstalk between a plurality of lenses. If the light crosstalk can be prevented only by the light shielding member 3, it is possible to eliminate the necessity of providing a light shielding film or a concave portion for preventing the light crosstalk in the lens array itself, and the manufacture of the lens array unit can be eliminated. It can be made easier. However, onWritingAs understood from,lightAs an auxiliary means for more reliably preventing the crosstalk, the second lens array 2 may be provided with a light-shielding film or a concave portion for blocking light. Of course, the first lens array 1 may be provided with a light shielding film, a concave portion, or the like.
[0081]
  A lens array unit U6 shown in FIG. 16 is a reference example of the present invention, and has a configuration in which the light blocking member 3 and one lens array 1 are combined. The lens array 1 includes a plurality of lenses 11 as convex lenses and a holder portion 10 that is integrally connected to the plurality of lenses 11.
[0082]
  In this lens array unit U6, since the lens array 1 is a convex lens array, it can be used for forming an inverted reduced image of a desired object. As described above, the lens array unit according to the present invention is not necessarily provided with two lens arrays like the lens array units U1 to U5 described above, and the number of lens arrays may be one. Absent. In this invention, it is also possible to make the structure which combined the lens array comprised as a concave lens array, and the light-shielding member.
[0083]
  The specific configuration of the present invention is not limited to the above-described embodiment, and various design changes can be made.
[0084]
  For example, the light shielding member referred to in the present invention does not have to be made of black synthetic resin, and can be configured in a dark color close to black or a color different from them. However, at least the inner wall surface of each through-hole is preferably black or a dark color close to it from the viewpoint of preventing unnecessary reflection of light. The light shielding member does not need to be manufactured by a resin molding process, and a specific manufacturing method thereof does not matter. The point that a plurality of light shielding members can be used is as described above.
[0085]
  In the lens array unit according to the present invention, the first and second lens arrays may not be directly superimposed. For example, a third lens array as a concave lens array is sandwiched between the first and second lens arrays, so that a so-called achromatic tamp lens array unit that can eliminate chromatic aberration can also be configured. . The lens array unit having such a configuration is suitable for an application for forming a color image.
[0086]
[0087]
  The optical apparatus according to the present invention is not limited to an image reading apparatus for reading a document image. As already described with reference to FIG. 14, by using the lens array unit according to the present invention, an image displayed on the screen of a liquid crystal display or other display device is formed and displayed at a predetermined location. It can also be configured as an optical device that is configured to be made to operate.
[Brief description of the drawings]
FIG. 1 shows a lens array unit according to the present invention.referenceIt is sectional drawing which shows an example.
FIG. 2 is an exploded perspective view of the lens array unit shown in FIG.
3 is a cross-sectional view taken along the line III-III in FIG.
4 is a cross-sectional view taken along the line IV-IV in FIG.
FIG. 5 is a cross-sectional view taken along the line VV of FIG.
FIG. 6 is a cross-sectional view of a principal part showing a step of resin-molding a lens array body of the first lens array.
7 is an operation explanatory diagram of the lens array unit shown in FIG. 1. FIG.
FIG. 8 is a cross-sectional view showing an example of an optical device according to the present invention.
FIG. 9 shows a lens array unit according to the present invention.oneIt is sectional drawing which shows an example.
10 is an exploded perspective view of the lens array unit shown in FIG.
FIG. 11 is a cross-sectional view showing another example of a light shielding member.
12A is a plan view showing another example of the light shielding member, and FIG. 12B is a cross-sectional view taken along line XII-XII in FIG.
FIG. 13 shows another lens array unit according to the present invention.referenceIt is a disassembled perspective view which shows an example.
FIG. 14 shows another lens array unit according to the present invention.referenceIt is a disassembled perspective view which shows an example.
FIG. 15 shows another lens array unit according to the present invention.referenceIt is sectional drawing which shows an example.
FIG. 16 shows a lens array unit according to the present invention.otherIt is sectional drawing which shows a reference example.
FIG. 17 is a perspective view showing a conventional technique.
FIG. 18 is a diagram for explaining the operation of the prior art.
[Explanation of symbols]
  U1-U6 lens array unit
  A Optical device
  1 First lens array
  2 Second lens array
  3,3A Shading member
  10 First holder part
  11 First lens
  11a First lens surface
  11b Second lens surface
  20 Second holder part
  21 Second lens
  21a Third lens surface
  21b Fourth lens surface
  30 Through hole
  30a Inner wall surface (through hole)
  71 cases
  73 Light source
  74 Light receiving element

Claims (5)

A plurality of first lenses as convex lenses each having a first lens surface and a second lens surface, and a first holder portion for holding the plurality of first lenses, and the first holder portion and the first lens are A first lens array integrally formed of a resin having translucency;
A plurality of second lenses as convex lenses each having a third and a fourth lens surface, and a second holder portion for holding the plurality of second lenses, and the second holder portion and the second lens are A second lens array that is integrally formed of a light-transmitting resin and is superimposed on the first lens array so that the third lens surface faces the second lens surface;
A plurality of light shielding members that have a plurality of through holes and are superimposed on the first lens array such that the plurality of through holes are arranged in front of the first lens surfaces;
It has
While each said 1st lens surface is made larger diameter than each through-hole of the said light-shielding member,
The plurality of light shielding members are connected in the row direction of the plurality of first lenses while adopting a structure in which at least a part of the plurality of light shielding members overlap each other in the thickness direction at the joint portion. A lens array unit, wherein the lens array unit is attached to the first lens array in a line. The lens array unit according to claim 1 , wherein each of the plurality of light shielding members has the same shape and size. 3. The lens array unit according to claim 1, wherein each of the first lens surfaces is convex, and at least a part of the first lens surface is fitted in each through hole of the light shielding member. An optical device comprising an imaging means for focusing light traveling from an object to form an image of the object at a predetermined position,
As the imaging means, characterized in that the lens array unit is used according to any one of claims 1 to 3, the optical device. A light source for illuminating the document; and a plurality of light receiving elements having a photoelectric conversion function; and
The optical apparatus according to claim 4 , wherein the light reflected by the original is focused by the lens array unit to form an image of the original on the plurality of light receiving elements.

Images