Method for manufacturing a rod lens array

Abstract

To provide a method for manufacturing a rod lens array which can suppress loosening when an exposed lens surface of a rod lens is polished in a state where base material surfaces of a lens block are bonded to each other and bundled.SOLUTION: A method for manufacturing a rod lens array includes: a first step of manufacturing a sheet-like base material containing a resin, and a member for lens fixation having an adhesive layer overlapping one surface of the base material; a second step of manufacturing a lens board sandwiching a plurality of rod-like rod lenses between each adhesive layer of two members for lens fixation; a second step of manufacturing a plurality of lens blocks by dividing the manufactured lens board; and a third step of polishing the rod lens that the manufactured lens block has, and obtaining a rod lens array.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a rod lens array having a configuration in which a plurality of rod-shaped lenses are arranged between two substrates, for example. The present invention also relates to a method for manufacturing a lens fixing member for sandwiching and fixing a plurality of the above-mentioned rod-shaped lenses therebetween. [Background technology]

[0002] Rod lens arrays used as optical components in copiers, printers, etc. have been known. This type of rod lens array has the shape of a lens block obtained by cutting and dividing a lens board in which a large number of rod-shaped lenses are sandwiched between two substrates. The substrate is, for example, a resin-containing plate such as a glass fiber reinforced plastic plate, and the lenses are, for example, glass or plastic rod lenses (see, for example, Patent Documents 1 and 2).

[0003] A known method for manufacturing this type of rod lens array includes an assembly process in which a large number of fiber-like lens materials are aligned on one substrate and the other substrate is placed on top of that and fixed in place; a filling and curing process in which resin is filled into the gaps in the assembled lens material array and cured; a cutting process in which the lens block bonded together with the cured resin is cut to a predetermined lens length; and a polishing process in which both cut end faces are polished (for example, Patent Document 3).

[0004] In the manufacturing method described in Patent Document 1, an addition reaction type silicone resin with a viscosity of 500 to 1500 mPa·s is used as the resin that is sucked and filled into the gaps of the lens blank array in the filling and curing step, and that contains 0.1 to 20 mass % of monodispersed spherical organic filler with an average particle size of 0.1 to 25 μm as a filler. According to the manufacturing method described in Patent Document 1, rod lens arrays having good alignment and optical properties and high strength can be stably manufactured. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 09-090105 [Patent Document 2] Patent No. 4319301 [Patent Document 3] Japanese Patent Application Laid-Open No. 2006-309078 Summary of the Invention [Problem to be solved by the invention]

[0006] In some manufacturing methods for rod lens arrays, a substrate is fabricated by press molding. In fabricating such a substrate, a substrate material is sandwiched between resin separators and then press-molded in this state. Alternatively, a lens board having rod lenses may be cut to a predetermined length to produce small lens blocks, and exposed lens surfaces may be formed on the cut ends of the rod lenses in the lens blocks. Specifically, a lens board having multiple rod lenses sandwiched between two substrates may be cut in the thickness direction to produce lens blocks, and exposed lens surfaces may be formed on the rod lenses. In such cases, to polish the formed exposed lens surfaces, multiple lens blocks are bundled together so that the exposed lens surfaces are flush with each other, and the substrate surfaces of the lens blocks are bonded together with an adhesive while bundled. Then, the exposed lens surfaces of the multiple lens blocks are polished while bundled.

[0007] However, because the resin separators used in the press molding process contain phenolic antioxidants such as dibutylhydroxytoluene (BHT), the phenolic antioxidant contained in the separator adheres to the substrate surface during the press molding process. If a substrate with a phenolic antioxidant adhered to its surface is used to bond the substrate surfaces of lens blocks together with an adhesive as described above, the phenolic antioxidant prevents the adhesive from exerting its inherent adhesive strength, resulting in a weakened adhesive strength and the problem of the bundled lens blocks easily coming apart during polishing.

[0008] In view of the above problems, an object of the present invention is to provide a method for manufacturing a rod lens array that can suppress separation when the exposed lens surfaces of the rod lenses are polished while the base surfaces of the lens blocks are bonded together and bundled together. Another object of the present invention is to provide a method for manufacturing a lens fixing member for manufacturing a lens board by sandwiching a plurality of rod lenses from both sides, which is capable of suppressing the above-mentioned dispersion. [Means for solving the problem]

[0009] The method for manufacturing a rod lens array according to the present invention includes the steps of: A first step of preparing a lens fixing member having a sheet-like substrate containing a resin and an adhesive layer superimposed on one surface of the substrate; a second step of preparing a lens board in which a plurality of rod-shaped rod lenses are sandwiched between the adhesive layers of the two lens fixing members, and further preparing a plurality of lens blocks by dividing the prepared lens board; a third step of polishing the rod lenses of the lens block to obtain a rod lens array; In the second step, the lens board is prepared by arranging the plurality of rod lenses with their longitudinal directions aligned, and the lens board is divided into a plurality of lens blocks by cutting the lens board in a thickness direction perpendicular to the longitudinal direction of the plurality of rod lenses, and exposed lens surfaces are formed in the lens blocks. In the third step, a plurality of the lens blocks are bundled together so that the exposed lens surfaces of the rod lenses are aligned, and the base surfaces of adjacent lens blocks are bonded to each other with an adhesive, and the exposed lens surfaces are polished to obtain a rod lens array; The first step is a cleaning step of cleaning the surface of the substrate to be bonded in order to reduce the amount of phenolic antioxidant adhering to the surface of the substrate to be bonded and improve the adhesive strength of the adhesive; In the purification step, the phenolic antioxidant is reduced by irradiating the substrate surface, to which the phenolic antioxidant is attached and which is to be bonded by the adhesive, with light containing ultraviolet light having a wavelength of 300 nm or less. According to the above manufacturing method, it is possible to prevent the lens blocks from coming apart when the exposed lens surfaces of the rod lenses are polished while the lens blocks are bundled together with their base surfaces bonded together.

[0010] In the above manufacturing method, the substrate may be an epoxy glass laminate.

[0011] In order to solve the above problems, a manufacturing method of a lens fixing member according to the present invention includes: A method for manufacturing a lens fixing member for manufacturing a lens fixing member in order to produce a rod lens array having a plurality of rod lenses arranged so that their optical axes are aligned and two lens fixing members that sandwich and fix the plurality of rod lenses therebetween, the method comprising: the lens fixing member has a sheet-like base material containing a resin and an adhesive layer superimposed on one surface of the base material, a cleaning step of cleaning the surfaces of the substrates by reducing the amount of a phenolic antioxidant attached to the surfaces of the substrates in order to improve adhesive strength when the surfaces of the substrates are bonded together with an adhesive during the process of producing the rod lens array; The purification step is characterized in that the phenolic antioxidant is reduced by irradiating the substrate surface, to which the phenolic antioxidant is attached and which is to be bonded by the adhesive, with light containing ultraviolet light having a wavelength of 300 nm or less. By adopting the above-described cleaning method, when lens blocks are produced using substrates whose surfaces have been cleaned as described above, and the exposed lens surfaces of the rod lenses are polished while the substrate surfaces of the lens blocks are bonded together and bundled, it is possible to prevent the bundled lens blocks from coming apart. [Effects of the Invention]

[0012] According to the method for manufacturing a rod lens array of the present invention, it is possible to suppress the dispersion of the lens blocks when the exposed lens surfaces of the rod lenses are polished in a state where the base surfaces of the lens blocks are bonded together and bundled. Furthermore, according to the manufacturing method of the lens fixing member of the present invention, it is possible to manufacture a lens fixing member that can suppress the above-mentioned scattering. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing an example of a rod lens array obtained by the manufacturing method of this embodiment. [Figure 2] FIG. 2 is a cross-sectional view that schematically shows how the substrate is produced. [Figure 3A] FIG. 3A is a schematic diagram showing the process of cleaning the substrate surface. [Figure 3B] FIG. 3B is a schematic diagram showing a state in which an adhesive layer is laminated on a substrate. [Figure 4A] FIG. 4A is a schematic diagram showing how a lens board is produced. [Figure 4B] FIG. 4B is a schematic diagram showing how the lens board is produced. [Figure 5A] FIG. 5A is a schematic diagram showing how a lens board is cut to produce a lens block. [Figure 5B] FIG. 5B is a schematic diagram showing how the lens board is cut to produce lens blocks. [Figure 6A] FIG. 6A is a schematic diagram showing how exposed lens surfaces of a plurality of bundled lens blocks are polished. [Figure 6B] FIG. 6B is a schematic diagram showing a state in which a plurality of lens blocks that were once bundled together are separated. [Figure 7] FIG. 7 is a graph showing the results of the TOF-SIMS analysis. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of a method for manufacturing a rod lens array according to the present invention will be described with reference to the drawings.

[0015] The rod lens array 10 manufactured by the manufacturing method of this embodiment has a plurality of rod lenses 12 with polished exposed lens surfaces, as shown in Fig. 1. A plurality of rod lens arrays 10 are used in combination, and are arranged, for example, so that the optical axes of the rod lenses 12 are aligned.

[0016] The manufacturing method of the rod lens array of this embodiment (hereinafter simply referred to as the manufacturing method) is as follows: A first step of preparing a lens fixing member 15 having a sheet-like substrate 11 containing a resin and an adhesive layer 13 superimposed on one surface of the substrate 11; a second step of preparing a lens board 10″ in which a plurality of rod-shaped rod lenses 12 are sandwiched between the adhesive layers 13 of two lens fixing members 15, and further preparing a plurality of lens blocks 10′ by dividing the prepared lens board 10″; a third step of polishing the rod lenses 12 of the lens block 10′ to obtain the rod lens array 10; In the second step, a lens board 10" is prepared by arranging the rod lenses 12 in the same longitudinal direction, and the lens board 10" is divided into a plurality of lens blocks 10' by cutting the lens board 10" in the thickness direction perpendicular to the longitudinal direction of the rod lenses 12, 12, and an exposed lens surface is formed in each of the lens blocks 10'. In the third step, a plurality of lens blocks 10' are bundled together so that the exposed lens surfaces of the rod lenses 12, 12 are aligned, and the substrate surfaces of adjacent lens blocks 10' are bonded to each other with an adhesive. In this state, the exposed lens surfaces are polished to obtain a rod lens array 10. The first step is a cleaning step of cleaning the surface of the substrate 11 to be bonded in order to reduce the amount of phenolic antioxidant adhering to the surface of the substrate 11 and improve the adhesive strength of the adhesive; In the purification step, the substrate surface to which the phenolic antioxidant is attached and which is to be bonded with an adhesive is irradiated with light containing ultraviolet light having a wavelength of 300 nm or less to reduce the phenolic antioxidant and purify the surface of the substrate 11. Here, "improving adhesive strength" includes at least one of allowing the adhesive strength inhibited by the phenolic antioxidant to be exerted at its original adhesive strength, and increasing the adhesive strength after purifying the substrate surface and reducing the phenolic antioxidant compared to before reduction.

[0017] In the first step, a sheet-like substrate 11 is prepared for sandwiching the rod lens 12 therebetween. The sheet-like substrate 11 contains at least a resin. The sheet-like substrate 11 may contain 20% by mass or more and 40% by mass or less of a resin. The thickness of the prepared sheet-like substrate 11 may be, for example, 0.1 mm or more and 3.0 mm or less.

[0018] The substrate 11 used in the first step is formed into a sheet shape by, for example, applying a press molding process to a substrate material. In the press molding process, a separator S is used to separate the sheet-shaped substrates 11 from each other.

[0019] The substrate material for producing the sheet-like substrate 11 includes, for example, a resin composition that can be deformed by press molding and fibers embedded in the resin composition. By subjecting such substrate material to press molding, the substrate 11, which is a fiber-reinforced plastic plate, is produced. The substrate 11 may be produced by press molding a plurality of sheet-like substrate materials that are stacked together. The fiber-reinforced plastic plate may be an epoxy glass laminate.

[0020] When the substrate 11 is an epoxy glass laminate, the substrate material includes, for example, a sheet-like epoxy resin composition before curing and glass fiber cloth (glass cloth). Specifically, the substrate material may be a prepreg obtained by impregnating glass fiber cloth with a solution containing an epoxy resin and then drying the prepreg. A plurality of such substrate materials (prepregs) are stacked and heated and press-molded by a press molding process to produce an epoxy glass laminate containing cured epoxy resin and glass fiber cloth. If necessary, a drying process may be further performed.

[0021] The separator S is, for example, a resin film. There are no particular limitations on the material of the separator S, and polyolefins such as polyethylene or polypropylene are used. As polypropylene, for example, biaxially oriented polypropylene may be used.

[0022] Separator S contains a phenolic antioxidant. Phenolic antioxidants are antioxidants that have a phenol structure in their molecules. Examples of phenolic antioxidants include dibutylhydroxytoluene (BHT) and butylhydroxyanisole (BHA).

[0023] In the press molding process, the multiple separators S are arranged so as to separate the multiple sheet-like substrate materials from one another. For example, as shown in Fig. 2, the multiple separators S are arranged between adjacent substrate materials (substrates 11) so as to separate the adjacent substrate materials (substrates 11). The separators S are subjected to pressure in the press molding process and adhere to the substrate materials (substrates 11), but have releasability that allows them to be easily peeled off from the substrate materials (substrates 11) after the press molding process.

[0024] In the press molding process, the pressure condition is, for example, 1 MPa or more and 30 MPa or less, and the temperature condition is, for example, 140°C or more and 210°C or less.

[0025] By the press molding process, the substrate 11 comes into direct contact with the separator S containing the phenolic antioxidant and is subjected to pressure. Therefore, the phenolic antioxidant adheres to the surface of the substrate 11, although in a relatively small amount. The phenolic antioxidant attached to the surface of the substrate 11 can cause a weakening of adhesive strength when the substrates are to be bonded to each other with an adhesive.

[0026] The substrate 11 may be further subjected to a heat treatment under a temperature condition higher than the temperature condition set in the press molding process. When the substrate 11 is a fiber-reinforced plastic plate such as an epoxy glass laminate, the heat treatment (high-temperature curing) can further improve the adhesion between the fibers and plastic contained in the fiber-reinforced plastic plate. As the substrate 11, a commercially available product produced by press molding as described above can be used.

[0027] In the manufacturing method of this embodiment, the first step includes, for example, a cleaning step of cleaning the surface of the substrate 11 to reduce the amount of the phenolic antioxidant attached to the surface of the substrate 11 as described above and improve the adhesive strength of the adhesive on the substrate surface to be bonded in the subsequent bonding step. The first step also includes a lens fixing member fabrication step of fabricating a lens fixing member 15 having a sheet-like substrate 11 containing a resin and an adhesive layer 13 superimposed on one surface of the substrate 11.

[0028] In the first cleaning step, the surface of the substrate 11 to be bonded later with an adhesive is cleaned by irradiating the surface with light containing ultraviolet light having a wavelength of 300 nm or less. This reduces the amount of phenolic antioxidant that has adhered to the surface of the substrate 11 by the press molding process described above. This improves the adhesive strength of the adhesive in the bonding step described in detail below, enabling adjacent substrate surfaces to be firmly bonded together.

[0029] Specifically, in the cleaning process, the substrate surface to which the phenolic antioxidant is attached is irradiated with ultraviolet light having a wavelength of 300 nm or less, thereby decomposing the phenolic antioxidant. This cleans the substrate surface to which the adhesive will be subsequently bonded, allowing the adhesive to fully exert its adhesive strength. This prevents the bundled lens blocks 10' from coming apart in the polishing process, which will be described in detail later. On the other hand, if a relatively large amount of phenolic antioxidant is present on the substrate surface, the adhesive may have poor wettability to the substrate surface or the phenolic antioxidant may inhibit the curing reaction of the curing adhesive. As a result, the adhesive may not exhibit its inherent adhesive strength. As a result, the bundled lens blocks 10' may easily come apart during the polishing process described in detail below.

[0030] The principle behind the decomposition of phenolic antioxidants on the surface of the substrate is believed to be as follows: When ultraviolet light of a specific wavelength is irradiated, ozone with strong oxidizing power is generated near the surface of the substrate 11. The generated ozone decomposes substances near the surface of the substrate 11 due to its oxidizing power. During this process, phenolic antioxidants such as BHT are decomposed. Although the ozone that contributed to the oxidation reaction is initially decomposed, new ozone can be generated by ultraviolet light of a specific wavelength. It is believed that the ozone generated in this way oxidizes and decomposes substances near the surface of the substrate 11. Therefore, it is believed that the phenolic antioxidant attached to the surface of the substrate 11 is also decomposed.

[0031] The light irradiated in the purification step (hereinafter also referred to as irradiation light) may contain ultraviolet light with a wavelength of 300 nm or less. The irradiation light preferably contains ultraviolet light with a wavelength of 260 nm or less, and more preferably contains at least ultraviolet light with a wavelength of 190 nm or less.

[0032] The irradiating light may contain two types of ultraviolet light with different wavelengths, for example, ultraviolet light with a wavelength of 180 nm or more and 190 nm or less, and ultraviolet light with a wavelength of 245 nm or more and 265 nm or less. The proportion of the energy of ultraviolet light with a wavelength of 185 nm in the irradiation energy (total spectral energy) of the irradiation light irradiated onto the surface of the base material 11 may be 5% or more, or may be 50% or less. Furthermore, when the energy of ultraviolet light of 245 nm or more and 265 nm or less is taken as 100%, the relative energy of ultraviolet light of 180 nm or more and 190 nm or less is preferably 5% or more, more preferably 25% or more, and may be 40% or less, or may be 35% or less.

[0033] The irradiation light irradiated onto the substrate 11 in the purification process is 450 [mJ / cm 2 ] per unit area of the substrate surface. 2 ] or more than 550[mJ / cm 2 The energy amount in one continuous irradiation may be in the above range, or the total energy amount in multiple irradiations may be in the above range.

[0034] In the purification process, the illuminance of the irradiated light on the surface of the substrate 11 is 20 [mW / cm 2 ] or more than 150[mW / cm 2 The distance from the irradiation light source to the surface of the substrate may be 5 mm or more and 80 mm or less. In the purification process, the distance from the irradiation light source to the substrate surface is set to 10 mm or more and 40 mm or less, and the illuminance is set to 50 [mW / cm 2 ] or more than 100[mW / cm 2 It is preferable to irradiate the material with light so that the phenol-based antioxidant is decomposed more reliably.

[0035] In the purification step, as described above, ozone gas is generated near the surface of the substrate 11 irradiated with the irradiation light. Since ozone gas contributes to the decomposition of the phenolic antioxidant, it is preferable to control the concentration of the generated ozone gas. In the purification step, it is preferable to control the ozone gas concentration in the space where the substrate 11 is irradiated with irradiation light to 90 ppm or more. Irradiation is performed on the substrate 11 placed in the space, and the ozone gas concentration can be reduced by exhausting the gas in the space and introducing new gas that does not contain ozone gas into the space. On the other hand, the ozone gas concentration can be increased by reducing the amount of newly introduced gas. More preferably, the ozone gas concentration is controlled to 90 ppm or more after the illuminance of the irradiation light and the distance from the irradiation light source to the substrate surface are set as described above. The ozone gas concentration may be controlled to 400 ppm or less. The ozone gas concentration may be measured at a location 10 mm or more and 50 mm or less away from the substrate 11.

[0036] In the purification step, the time for irradiating the substrate surface with irradiation light may be 2 seconds or more and 15 seconds or less. The number of times for irradiating the substrate surface with irradiation light may be one or more. The time for each irradiation may be within the above range, and the total time for irradiation (total time) may be within the above range.

[0037] The cleaning step may be carried out before bonding the substrate surfaces of the lens blocks 10' together with an adhesive, as will be described in detail later. In other words, the order of the lens fixing member fabrication step and the cleaning step is not particularly limited. In other words, the cleaning step may be carried out after the lens fixing member fabrication step, or before the lens fixing member fabrication step. Furthermore, the cleaning step may be carried out both before and after the lens fixing member fabrication step. In order to prevent the adhesive layer 13 from deteriorating due to the above-mentioned ultraviolet radiation, it is preferable to carry out a cleaning step before carrying out the lens fixing member fabrication step.

[0038] In the first step, a lens fixing member fabrication step, an adhesive layer 13 is superposed on one surface of a sheet-like substrate 11, thereby fabricating a lens fixing member 15.

[0039] For example, as shown in Figure 3A, with the substrate 11 positioned so that the thickness direction is the vertical direction, the ultraviolet light is irradiated from below onto the lower surface of the substrate 11, and then, as shown in Figure 3B, an adhesive layer 13 is superimposed on the upper surface of the substrate 11.

[0040] The adhesive layer 13 is formed of a fixing resin composition for fixing the plurality of rod lenses 12, 12 between the two substrates 11, 11. Such a fixing resin composition may be formed into a sheet to form the adhesive layer 13.

[0041] The fixing resin composition forming the adhesive layer 13 preferably contains a curable resin (reactive compound) that is cured by heat treatment. Examples of the reactive compound include epoxy resins and modified products thereof, and urethane resins and modified products thereof.

[0042] In addition to the above-mentioned curable resin, the fixing resin composition may further contain silicone resin and modified products thereof, polyester resin and modified products thereof, acrylic resin and modified products thereof, polyamide resin and modified products thereof, and the like.

[0043] In the manufacturing method of this embodiment, the second step includes a lens board manufacturing step of manufacturing a lens board 10" in which two lens fixing members 15 are used to sandwich a plurality of rod lenses 12 between each adhesive layer 13, and a lens block manufacturing step of manufacturing a plurality of lens blocks 10' by cutting and dividing the manufactured lens board 10".

[0044] In the second step, the lens board fabrication step, a plurality of rod-shaped rod lenses 12 are prepared. As shown in FIG. 4A, the plurality of rod lenses 12 are arranged between the two lens fixing members 15, 15 fabricated as described above, and the plurality of rod lenses 12 are sandwiched between two adhesive layers 13 to fabricate a lens board 10". In other words, two base materials 11 are stacked together so that a plurality of rod lenses 12, which are aligned with their longitudinal directions aligned, are sandwiched between the adhesive layers 13 of the lens fixing members 15. Then, a lens board 10" as shown in FIG. 4B is produced. In the lens board manufacturing process, multiple rod lenses 12 may be sandwiched as described above while being heated, thereby imparting fluidity to the fixing resin composition forming the adhesive layer 13 and making it easier for the fixing resin composition to penetrate between adjacent rod lenses 12.

[0045] The rod lens 12 may be made of plastic or glass, and may have a diameter of, for example, 0.05 mm or more and 2.00 mm or less.

[0046] In the lens board manufacturing process, the rod lenses 12 are aligned in the longitudinal direction. Two lens fixing members 15, each having an adhesive layer 13 superimposed on one side of the substrate 11 (the side to be placed inside), are used to fix the rod lenses 12 arranged between the two substrates 11 with the adhesive layer 13. Two lens fixing members 15 are arranged so that the adhesive layer 13 is disposed inside the substrate 11, and multiple rod lenses 12 are sandwiched between the two lens fixing members 15, whereby the fixing resin composition of the adhesive layer 13 surrounds the multiple rod lenses 12. This allows each of the multiple rod lenses 12 to be fixed in a predetermined position between the two substrates 11.

[0047] In the second step, the lens block manufacturing step, the lens board 10" is cut so as to divide the rod lenses 12, 12 inside the lens board 10" in the longitudinal direction, thereby exposing at least one end of the cut rod lenses 12 to form exposed lens surfaces. In other words, in order to form exposed lens surfaces on the rod lenses 12, the lens board 10" is cut in the thickness direction so as to divide the rod lenses 12 in the longitudinal direction.

[0048] In the lens block production process, as shown in Figures 5A and 5B, for example, the lens board 10" is cut in the thickness direction so that the rod lenses 12 are separated in the longitudinal direction into multiple pieces. This increases the number of rod lenses 12, and lens surfaces are exposed at the ends of the cut rod lenses 12. Thus, exposed lens surfaces are formed. The lens board 10" is subjected to the cutting process multiple times, and multiple lens blocks 10' are produced from one lens board 10". At the cut surfaces of the lens board 10", the exposed lens surfaces and the end faces of the substrate 11 are flush with each other.

[0049] In the manufacturing method of this embodiment, the third step includes a bonding step in which multiple lens blocks 10′ are lined up and bundled together so that the base surfaces of adjacent lens blocks 10′ face each other, and the base surfaces are bonded together with an adhesive, and a polishing step in which the multiple exposed lens surfaces of adjacent lens blocks 10′ are polished while they are bonded and bundled together to obtain a rod lens array 10.

[0050] In the third bonding step, first, an adhesive is applied to the substrate surface of each of the lens blocks 10' fabricated in the lens block fabrication step. The substrate surface to which the adhesive is applied is the surface opposite the surface facing the rod lenses 12. In other words, the substrate surface to which the adhesive is applied is the substrate surface facing outward. Next, the lens blocks 10' with adhesive applied to their base surfaces are bundled together. At this time, the lens blocks 10' are bundled together so that the cut surfaces of the lens blocks 10' are flush with each other. In other words, the lens blocks 10' are bundled together so that the exposed lens surfaces of the lens blocks 10' are aligned along the same plane. At this time, the lens blocks 10' are lined up so that the base surfaces to which adhesive is applied are adjacent and facing each other.

[0051] Examples of adhesives used in the bonding step include silicone adhesives, moisture-curable modified silicone adhesives, silyl group-containing polymer adhesives, cyanoacrylate-containing adhesives, etc. Commercially available products can be used as these adhesives. The adhesive used in the bonding step is preferably a moisture-curing adhesive that cures when a polymerization reaction is initiated by moisture in the air, and is preferably a cyanoacrylate-containing adhesive or a silyl group-containing polymer adhesive. Moisture-curing adhesives tend to be difficult to cure under conditions where a relatively large amount of a phenolic antioxidant, such as dibutylhydroxytoluene, is present, as the polymerization reaction is inhibited, and as a result, sufficient adhesive strength may not be achieved. In this embodiment, the phenolic antioxidant attached to the substrate surface to be bonded is decomposed by light irradiation in the cleaning process, allowing the adhesive to exert sufficient adhesive strength. This prevents the bundle of lens blocks 10' from coming apart during the polishing process, as will be described in detail later.

[0052] In the third polishing step, the exposed lens surfaces of the bundled lens blocks 10' are polished to polish the exposed lens surfaces, thereby obtaining the rod lens array 10. The polishing process is performed, for example, at room temperature, using a polishing apparatus having a circular rotating polishing disc G, as shown in FIG. 6A. The polishing disc G may have a polishing pad made of a resin containing an appropriate abrasive, and this polishing pad may be provided on the surface that contacts the lens block 10′. The polishing apparatus is configured to polish the exposed lens surface of the lens block 10′ by pressing the exposed lens surface against the polishing disc G and moving the polishing disc G along the polishing disc G. FIG. 6A shows, as an example, a workpiece (object to be processed) formed by bundling four lens blocks 10′ together, but this is not a limitation. For example, the workpiece may be formed by bundling a greater or lesser number of lens blocks 10′ together.

[0053] In the polishing process, when the bundled lens blocks 10' undergo the polishing process described above, the exposed lens surfaces are pressed against the polishing disc G and rubbed against the surface of the polishing disc G, so that the bonded multiple lens blocks 10' are subjected to a force that could break apart. Therefore, if the adhesive strength of the base surfaces bonded together by the adhesive is weak, there is a risk of the lenses breaking apart, as shown in Figure 6B, for example. In this embodiment, the phenolic antioxidant attached to the substrate surface is decomposed by the light irradiation in the above-described purification step, allowing the adhesive to fully exert its adhesive strength, thereby preventing a decrease in adhesive strength on the substrate surface and preventing the above-described separation.

[0054] After the polishing process, the bundled lens blocks 10' can be released from the bundled state by, for example, immersing them in a solvent or subjecting them to mechanical peeling, thereby obtaining a plurality of rod lens arrays 10 each having exposed lens surfaces polished by the polishing process.

[0055] The rod lens array 10 manufactured as described above is used as an optical component built into, for example, a printer, a copier, an electronic whiteboard, or the like.

[0056] Next, an embodiment of a method for manufacturing a lens fixing member according to the present invention will be described.

[0057] The method for manufacturing a lens fixing member of this embodiment corresponds to the first step described above. In detail, the method for manufacturing the lens fixing member of this embodiment is as follows: A method for manufacturing a lens fixing member for manufacturing a lens fixing member in order to produce a rod lens array having a plurality of rod lenses arranged so that their optical axes are aligned and two lens fixing members that sandwich and fix the plurality of rod lenses, comprising the steps of: The lens fixing member 15 has a sheet-like substrate 11 containing a resin and an adhesive layer superimposed on one surface of the substrate 11, a cleaning step of cleaning the surface of the substrate 11 by reducing the amount of a phenolic antioxidant adhering to the surface of the substrate 11 in order to improve adhesive strength when the substrate surfaces are bonded together with an adhesive during the process of manufacturing the rod lens array 10; In the purification step, the surface of the substrate to which the phenolic antioxidant is attached and which is to be bonded with an adhesive is irradiated with light containing ultraviolet light having a wavelength of 300 nm or less, thereby reducing the phenolic antioxidant and purifying the surface of the substrate 11.

[0058] The manufacturing method of the rod lens array and the manufacturing method of the lens fixing member of this embodiment are as exemplified above, but the present invention is not limited to the manufacturing methods exemplified above. That is, various forms that can be adopted in general methods for manufacturing rod lens arrays can be adopted within the scope that does not impair the effects of the present invention. [Example]

[0059] The present invention will now be described in more detail with reference to experimental examples, but the present invention is not limited to these examples.

[0060] The rod lens array manufacturing method was carried out as follows to manufacture the rod lens arrays of the respective examples.

[0061] <Rod lens array materials and components> Rod lens 0.5mm diameter rod lens (commercially available) ·Base material Fiber reinforced plastic plate (FRP epoxy glass laminate, commercially available) However, since the separator contained dibutylhydroxytoluene (BHT) and was produced by press molding as described above, BHT was attached to the surface. Adhesive layer that is overlaid on the substrate An adhesive layer formed from the above-mentioned curable resin (reactive compound) ·glue ThreeBond silyl group-containing special polymer: Product name "TB1530" <Purification step in the first step (manufacturing method of lens fixing member)> The substrate surface to be bonded in the subsequent bonding step was irradiated with light containing ultraviolet light. The conditions for light irradiation varied depending on the example. Specifically, irradiation was performed under the irradiation conditions shown in Table 1. However, unless otherwise specified, the following irradiation conditions were used. Illuminance: 50~100[mW / cm 2 ] Irradiation time: 4 to 11 seconds Ozone exposure time: 10 to 30 seconds The light irradiation device used consisted of Iwasaki Electric's UV lamp "QGL400U-3B", illuminance meter "UVPF-A2", and light receiving head "PD-254A2". The wavelength and energy ratio of the ultraviolet light in the irradiation light are shown in Table 1. The total energy amount (cumulative light amount) per unit area of the substrate surface was 500±50mJ / cm. 2 The ozone concentration under each UV irradiation condition was measured using an ozone concentration meter, "EG-700EIV" manufactured by Ebara Jitsugyo Co., Ltd. Details of each condition listed in Table 1 are as follows. Distance from the light source: The distance between the UV lamp and the substrate surface that is irradiated with UV light. Exhaust blower frequency: The rotation speed of the motor that drives the blower that exhausts ozone gas. Exhaust volume: The amount of gas (air) exhausted by the exhaust blower per unit time Ozone concentration: The ozone concentration in the space where the substrate is irradiated with UV light inside the equipment. Immediately after the irradiation in the cleaning step, the next step of manufacturing a lens fixing member was carried out using the substrate that had undergone the cleaning step. <First step (lens fixing member manufacturing method): lens fixing member manufacturing step> The adhesive layer was laminated onto the substrate while heating at 100 to 160° C. to prepare a lens fixing member. <Second process: lens board manufacturing process> A number of rod lenses were aligned in a row with their longitudinal directions facing in the same direction, and two lens fixing members were stacked together so that they were sandwiched between the adhesive layers of the two lens fixing members, thereby producing a lens board. <Second step: lens block manufacturing process> The lens board was cut in the thickness direction to produce a plurality of small lens blocks measuring 2 mm (H) x 2-20 mm (W) x 100-400 mm (L). <The third step is the adhesive process> The lens blocks were bonded together using the adhesive, and a lens block assembly was produced in which multiple lens blocks (3 to 300 pieces) were bundled together. <The third step is polishing> The exposed lens surfaces of the lens block assembly were pressed against a polishing plate equipped with a polishing pad, and the lens block assembly was rotated to polish the exposed lens surfaces.

[0062] (Examples 1 to 22, Comparative Example 1) Basically, the rod lens array was manufactured by the above-mentioned method. Table 1 shows the differences in manufacturing conditions between the manufacturing methods of the examples and comparative examples.

[0063] <Test to confirm decomposition of dibutylhydroxytoluene (BHT) by ultraviolet irradiation (TOF-SIMS test)> Separately, a substrate (FRP) was prepared after undergoing a cleaning process under the same conditions as in Example 2. A substrate (FRP) was also prepared without undergoing the cleaning process. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was then performed on the surface of each substrate (FRP surface). The analysis method was in accordance with the general TOF-SIMS test method. 15 H 23 + , and C 16 H 23 - The relative intensity of each was measured, and the results are shown in Figure 7. As can be seen from FIG. 7, it can be said that the BHT attached to the substrate surface was decomposed by irradiating it with light containing ultraviolet light of a specific wavelength in the purification process.

[0064] <Evaluation test for loosening of bundled lens blocks> When the above-mentioned polishing process was carried out, the number of times that scattering occurred was counted. The evaluation results are shown in Table 1. In addition, the influence of "ozone concentration" and "distance from the light source" on the results of the evaluation test (presence or absence of scattering) is summarized in Table 2.

[0065] [Table 1]

[0066] [Table 2]

[0067] As can be seen from Table 1, the manufacturing method of the example was able to prevent the bundled lens blocks from coming apart when the exposed lens surfaces of the rod lenses were polished while the base surfaces of the lens blocks were bonded together and bundled together, compared to the manufacturing method of the comparative example. As can be seen from Table 2, the higher the ozone concentration and the closer the distance to the light source during the purification process, the more effectively the generation of fragments was suppressed. [Industrial Applicability]

[0068] The method for manufacturing a rod lens array of the present invention is suitably used for manufacturing a rod lens array to be built into optical devices such as a printer, a copier, and an electronic whiteboard. The manufactured rod lens array is suitably used as a component of the optical device described above. [Explanation of symbols]

[0069] 10: Rod lens array, 10': lens block, 10": lens board, 11: substrate, 12: rod lens, 13: adhesive layer, 15: lens fixing member, S: Separator.

Claims

1. A first step of preparing a lens fixing member having a sheet-like substrate containing a resin and an adhesive layer superimposed on one surface of the substrate; a second step of preparing a lens board in which a plurality of rod-shaped rod lenses are sandwiched between the adhesive layers of the two lens fixing members, and further preparing a plurality of lens blocks by dividing the prepared lens board; a third step of polishing the rod lenses of the lens block to obtain a rod lens array; In the second step, the lens board is prepared by arranging the plurality of rod lenses with their longitudinal directions aligned, and the lens board is divided into a plurality of lens blocks by cutting the lens board in a thickness direction perpendicular to the longitudinal direction of the plurality of rod lenses, and exposed lens surfaces are formed in the lens blocks. In the third step, a plurality of the lens blocks are bundled together so that the exposed lens surfaces of the rod lenses are aligned, and the base surfaces of adjacent lens blocks are bonded to each other with an adhesive, and the exposed lens surfaces are polished to obtain a rod lens array; The first step comprises: a cleaning step of cleaning the surface of the substrate to be bonded in order to reduce the amount of phenolic antioxidant adhering to the surface of the substrate to be bonded and improve the adhesive strength of the adhesive; In the purification step, the phenolic antioxidant is reduced by irradiating a surface of the substrate to which the phenolic antioxidant is attached, the surface of the substrate being bonded with the adhesive, with light containing ultraviolet light having a wavelength of 300 nm or less. A method for manufacturing a rod lens array.

2. The method for manufacturing a rod lens array according to claim 1 , wherein the substrate is an epoxy glass laminate.

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