JP2006106361A - Method for manufacturing light guide plate, and light guide plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light guide plate manufacturing method that can suppress lowering of dimensional accuracy of a core or a clad caused by hardening/shrinking and that makes manufacturing possible through a fewer number of processes, and also to provide the light guide plate. <P>SOLUTION: A planar clad 13 having on one side a plurality of narrow groove lines 12 formed on a clad supporting substrate 10 is brought in press-contact with a core material 21 which has a higher refractive index than the clad 13 as well as translucency and plasticity; thus, the core material 21 is formed into a shape corresponding to the clad 13. In addition, the core material 21 is hardened in the press-contact state to separate a core supporting substrate 20. According to this manufacturing method, the core material 21 is hardened in a state held between the core supporting substrate 20 and the clad 13 on the clad supporting substrate 10; therefore, the lowering of the dimensional accuracy can be suppressed which is caused by the hardening/shrinking of the core material 21. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light guide plate manufacturing method and a light guide plate, and more particularly, to a light guide plate manufacturing method and a light guide plate in which a plurality of cores are arranged in parallel at a predetermined pitch on a substrate.

  In recent years, image forming apparatuses such as copiers, printers, facsimile machines, and multi-function machines have been required to have a function of printing high-resolution images in a short time.

  In order to print a high-resolution image, it is necessary that a light source for forming a latent image of the printed image on the photoconductor can be exposed at a narrow pitch in the main scanning direction. In order to perform printing in a short time, it is necessary to form a latent image on the photoconductor in a short time, that is, to sufficiently increase the amount of light applied to the photoconductor to shorten the exposure time. .

  As a typical light emitting element used for the light source, there is an LED (Light Emitting Diode). However, in order to arrange such light emitting elements at a narrow pitch, it is necessary to make the light emitting elements small, and thus the light emitting area of the light emitting elements is inevitably small. For this reason, as the light emitting area decreases, the amount of light emitted from the light emitting element decreases, and it is difficult to achieve both the arrangement of the light emitting elements at a narrow pitch and the shortening of the exposure time.

  Therefore, the present applicant has proposed a light source 100 shown in the perspective view of FIG. As shown in FIG. 7, in the light source 100, a core (light guide path) 102 extending on a substrate 101 in a direction perpendicular to the surface of the photoreceptor 500 (hereinafter referred to as a light transmission direction) has a surface of the photoreceptor 500. A light emitting element 300 having a plurality of light guide plates 200 arranged in a direction parallel to the direction (hereinafter referred to as a main scanning direction) and having a long light emitting surface in the light transmission direction is formed on the upper surface of each core 102. Yes.

  The light D emitted from the light emitting element 300 repeats total reflection in the core 102 and is emitted from the emission surface which is one end surface of the core 102 in the light transmission direction. In addition, the reflective material 103 is laminated | stacked on the other end surface of the optical transmission direction of the core 102, and the leakage of the light D is reduced.

  As described above, the light emitted from the core 102 is imaged on the surface of the photoreceptor 500 through the light transmission means 400 such as a GI (Graded Index) fiber lens or a rod lens. Therefore, the exit surfaces of the plurality of cores have the same area as that required for one pixel of the latent image formed on the photoreceptor 500 and are arranged at the same pitch as the pitch between the pixels. It is possible to realize the light source 100 that is arranged at a narrow pitch in the scanning direction and can emit a large amount of light.

  FIG. 7 conceptually shows the light source 100 using the light guide plate 200 in which the cores 102 are simply arranged on the substrate 101 at predetermined intervals. In order to facilitate the formation of the light emitting element 300, a clad 102a having a lower refractive index than the core 102 is interposed between the cores 102 so that the upper surface of the light guide plate 200 is flat. Below, the manufacturing process of the light-guide plate 200 provided with this clad | crud 102a is demonstrated based on FIG.8 and FIG.9.

  As shown in FIG. 8A, first, a liquid clad material 102b made of thermosetting or UV (Ultra Violet) curable resin is applied onto the substrate 101 by spin coating, screen printing, or the like, and then heating or UV light is applied. The clad 102a is formed by performing a curing process such as irradiation.

  Next, a core material 102c having liquid translucency made of, for example, UV curable resin is applied on the clad 102a. As shown in FIG. 8B, a mask 105 having a plurality of openings at predetermined intervals is disposed on the core material 102c, and the core material 102c is irradiated with UV light E through the mask 105. Is done. At this time, the core material 102c located in the portion shielded by the mask 105 is not cured. Therefore, by removing the uncured core material 102c by cleaning using, for example, an organic solvent, a pattern of the core 102 corresponding to the mask 105 is formed as shown in FIG. 8C.

  Subsequently, as shown in FIG. 8D, a liquid clad material 102b is filled between the patterns of the core 102 and subjected to curing treatment, and each core 102 is covered with the clad 102a. Finally, the light guide plate 200 is obtained by polishing the clad 102a from the upper surface to expose the surface of the core 102 (FIG. 8E).

  A light emitting element 300 using an organic or inorganic light emitting material is formed on the upper surface of each core 102 of the light guide plate 200 formed as described above. That is, the lower layer electrode 301 and the light emitting layer 302 are sequentially formed with a film thickness of submicron order by vapor deposition or spin coating, and the upper layer electrode 303 is formed on the upper surface of the light emitting layer 302. Each layer may be individually formed on each core 102. Here, in order to facilitate the manufacturing process, the lower layer electrode 301 forms an individual transparent electrode on each core 102, and the light emitting layer 302 and the upper layer are formed. The electrode 303 forms a common layer (a single layer covering all the lower layer electrodes 301) in each light emitting element 300 (FIG. 8F). In this case, the film thickness of the organic light emitting layer 302 is set to a film thickness within a range in which good light emission characteristics can be obtained according to the material, and the film thickness of the lower electrode 301 is such that the organic light emitting layer 302 has each lower electrode 301. Is set to a film thickness equal to or smaller than the film thickness of the organic light emitting layer 302. Further, the upper electrode 303 is set to a film thickness such that the electric resistance of the upper electrode 303 itself does not deteriorate the light emission characteristics of the organic light emitting layer 302.

  On the other hand, when a non-photosensitive material is used as the core material 102, the pattern of the core 102 cannot be formed by UV light irradiation through the above-described mask 105. Therefore, the light guide plate 200 is manufactured as shown in FIG. Formed by the process.

  First, similarly to the above, the core material 102c is formed on the clad 102a formed on the substrate 101 by vapor deposition or sputtering (FIG. 9A).

  Next, a mask pattern 106 made of a nitride film arranged at a predetermined pitch is formed on the core material 102c, for example, by photolithography (FIG. 9B). Then, using the mask pattern 106 as an etching mask, the core material 102c is etched to form the core 102 pattern (FIG. 9C).

  Subsequently, after removing the mask pattern 106 with phosphoric acid or the like, in the same manner as described above, a liquid clad material 102b is filled between the patterns of the core 102, and a curing process is performed, so that the clad 102a covering the core 102 is formed. This is formed (FIG. 9D).

  Thereafter, similarly to the above, the light guide plate 200 is obtained by polishing the clad 102a covering the core 102 from the upper surface to expose the surface of the core 102 (FIG. 9E).

Further, a light emitting element 300 using an organic light emitting material or the like is formed on the upper surface of each core 102 of the light guide plate 200 formed as described above (FIG. 9F).
International Publication No. 2004/039595 Pamphlet

  As described above, since the material of the core 102 and the material of the clad 102a are different, the hardness of the core and the hardness of the clad are usually different. When polishing is performed on a surface in which materials having different hardnesses are mixed as described above, the polishing amount of the high hardness material is smaller than the polishing amount of the low hardness material. For this reason, when the upper surface of the light guide plate 200 is polished, a step corresponding to the hardness difference between the core 102 and the clad 102a is formed at the interface between the core 102 and the clad 102a.

  As described above, the light emitting layer 302 and the upper layer electrode 303 are formed as layers covering the entire upper surface of the light guide plate 200. However, when a layer covering the entire upper surface of the light guide plate 200 is formed in a state where the level difference due to the polishing is generated, the upper layer electrode 303 may be disconnected as shown by an arrow A in FIG. In order to prevent this disconnection, for example, even when the film thickness of the upper layer electrode 303 is increased, the lower layer electrode 301 and the upper layer electrode 303 to be separated with the light emitting layer 302 interposed therebetween are short-circuited. become. Further, even if such defects as disconnection or short circuit do not become apparent at the time of manufacture, the long-term reliability of the organic light emitting device is surely lowered due to the presence of the step.

  On the other hand, the liquid material used as the core material 102c and the clad material 102b has a property of shrinking upon curing. For example, in the curing process for forming the pattern of the core 102 as shown in FIG. 8B described above, the curing shrinkage causes the pattern to be deformed or the pattern arrangement interval (pitch) to shift.

  Further, in the curing process in the case where the liquid material as shown in FIG. 8D or 9D is applied to the entire surface, the shrinkage amount of the clad material 102b due to the cure shrinkage is not restricted by the substrate 101. Therefore, the clad 102a may be warped. Such warping results in a decrease in the pattern arrangement accuracy of each core 102 as a result.

  The decrease in the dimensional accuracy of each core 102 is particularly the case where the cores 102 are arranged at a narrow pitch, as in the light source of the image forming apparatus aiming at the above-described high resolution, and the amount of light of each pixel is ensured. Therefore, there is a problem when the size of the light guide plate 200 is increased.

  The present invention has been proposed based on the above-mentioned conventional circumstances, and can suppress the deformation of the core and the clad due to curing shrinkage, and can be manufactured with a smaller number of processes than the conventional manufacturing method. It is an object of the present invention to provide a method for manufacturing a light guide plate and a light guide plate.

  The present invention employs the following means in order to achieve the above object. That is, in the method for manufacturing a light guide plate according to the present invention, first, a plate-like clad having a plurality of fine grooves on one side is formed on a clad support substrate. In addition to the formation of the clad, a core material layer having a higher refractive index than the clad and having a light transmitting property is supplied onto the core support substrate by, for example, screen printing or spin coating. Form.

  Next, the narrow groove is filled by pressing the surface of the clad support substrate with the clad narrow groove facing the core material on the core support substrate and curing the core material in the pressed state. A light guide plate having a plurality of cores is formed.

  According to this manufacturing method, since the core material is cured while being sandwiched between the core support substrate and the clad constrained by the clad support substrate, the deformation of the core due to curing shrinkage can be suppressed. For this reason, the light guide plate can be formed with high accuracy.

  Further, in the above method, the clad used for molding the core material may be formed using a fine processing technique such as a known photolithography, but a plastic material such as a liquid material is used for the clad material, It is preferably formed by press molding using a mold for cladding such as a metal mold. At this time, the clad material is cured while being pressed against the clad mold.

  In this way, the process can be simplified compared to photolithography consisting of multiple processes such as resist coating, exposure, and development. In addition, since deformation of the clad due to curing shrinkage is suppressed by the clad mold and the clad support substrate, the clad narrow groove can be formed with high accuracy.

  Furthermore, if the surface on which the core of the core support substrate is formed is a smooth surface, the surface of the core that is exposed after the core support substrate is separated becomes a smooth surface. Therefore, the polishing required in the conventional manufacturing process is necessary. It is also possible to omit the process. Here, the smooth surface is a surface having sufficiently small surface roughness and flatness compared to the film thickness of the lower layer electrode of the light emitting element formed on the surface of the core.

  In addition, the clad support substrate preferably includes a spacer that restricts the distance between the clad support substrate and the core support substrate to a specific distance when the clad is pressed against the core material to mold the core material. .

  The spacer limits the minimum distance at which the clad support substrate and the core support substrate can approach. This makes it easier to manage the distance between the two substrates when the clad is pressed against the core material, and because the two substrates do not approach the distance limited by the spacer, so that the clad contacts the core support substrate. And the malfunction that the partition which partitions off each fine groove is damaged can be prevented. In addition, the space | interval restrict | limited by a spacer should just be larger than the depth of the narrow groove | channel of a clad.

  In the above manufacturing method, first, the core is formed on the core support substrate, and the surface on which the core of the core support substrate is formed is used as a mold, and the plastic clad material disposed on the clad support substrate is molded. Also, similar actions and effects can be obtained.

  According to the present invention, the core material and the clad material are hardened by being sandwiched between any two of the core support substrate, the clad support substrate, the core mold, and the clad mold. Decrease in dimensional accuracy due to hardening shrinkage of the material and the clad material can be suppressed. Therefore, a light guide plate that can be used for a light source or the like of the image forming apparatus can be accurately manufactured.

  Furthermore, if the surface on which the core of the core support substrate is formed is a smooth surface, the surface of the core exposed by the separation of the core support substrate can be made smooth, which is necessary in the conventional manufacturing method. The polishing process can be omitted, and the process can be further simplified.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

  1, 2, and 3 are schematic diagrams illustrating a manufacturing process of the light source 1 of the image forming apparatus to which the light guide plate 2 according to the present embodiment is applied. FIG. 4 is a schematic plan view of the light source 1.

  Like the conventional light guide plate 200 shown in FIGS. 8 and 9, the light guide plate 2 according to the present embodiment includes a clad 11 including a plurality of narrow grooves 12 provided on a substrate at a predetermined pitch, And a core 22 filled in the narrow groove 12.

  Hereinafter, based on FIGS. 1 to 3, a method for manufacturing the light guide plate 2 according to the present embodiment and a method for manufacturing the light source 1 of the image forming apparatus to which the light guide plate 2 is applied will be described.

  First, as shown in FIG. 1A, on a clad support substrate 10 made of silicon, quartz, glass or the like, a plastic clad material 11 made of a thermosetting or UV curable resin material or the like is screen-printed, spinned. A layer of the clad material 11 is formed by being supplied by coating, dropping or the like. In the example of FIG. 1A, the clad support substrate 10 is a light-transmitting glass substrate having a thickness of about 1 mm, and the clad material 11 is a UV curable epoxy resin having a refractive index of 1.5. is there.

  The clad support substrate 10 includes a spacer 40 described in detail later. Since the thickness (height) of the spacer 40 is important in a later process, it is not preferable that the clad material 11 is applied to the upper surface thereof. For this reason, when the coating of the clad material 11 is performed using a method in which an application region cannot be selected, such as spin coating, masking or the like is performed on the spacer 40.

  Next, as shown in FIGS. 1B and 1C, a cladding mold 50 made of a material such as tungsten carbide (WC) or quartz is pressed against the cladding material 11. A plurality of protrusions corresponding to each narrow groove 12 are formed on the joint surface of the cladding mold 50 with the cladding material 11 so that a plurality of narrow grooves 12 having a predetermined pitch are formed in the cladding material 11 during pressure welding. 51 is engraved.

  In the process of pressing, the clad material 11 is filled between the ridges 51 of the cladding mold 50 and molded into a shape corresponding to each ridge 51. At this time, the extra clad material 11, which no longer exists between the clad support substrate 10 and the clad mold 50, is optically transmitted by the protrusions 51 opened to the outside at the outer edge of the clad mold 50. It is pushed out from the end in the direction (end in the longitudinal direction). The molding is preferably performed under vacuum such as in a chamber in order to prevent bubbles from being trapped in the clad material 11.

  Further, when the clad mold 50 is pressed against the clad support substrate 10, the clad mold 50 and the clad support substrate 10 are prevented from contacting each other, and the clad mold 50 and the clad support substrate 10 are prevented from contacting each other. The spacer 40 is provided between the cladding mold 50 and the cladding support substrate 10 in order to limit the distance W1 to the specific distance. The spacer 40 can adopt any structure as long as the distance between the cladding support substrate 10 and the cladding mold 50 can be determined. However, the spacer 40 is formed integrally with the cladding support substrate 10 for the reason described later. It is preferable that it is the structure.

  In the present embodiment, the spacer 40 is configured as a convex portion integrally formed on the clad support substrate 10 and extending in the optical transmission direction. The convex portion may be formed by any method such as cutting or injection molding, and the formation method is not particularly limited. The spacer 40 does not need to be formed integrally with the clad support substrate 10, and the spacer 40 made of a member separate from the clad support substrate 10 is fixed to the clad support substrate 10 with an adhesive or the like. Also good.

  Subsequently, as shown in FIG. 1C, the cladding material 11 is irradiated with a sufficient amount of UV light E in a state where the cladding mold 50 is pressed against the cladding material 11 via the spacer 40. Then, the curing process of the clad material 11 is performed.

  As described above, in this embodiment, a glass substrate is used as the clad support substrate 10, and thus the UV light E is applied to the clad material 11 through the clad support substrate 10. Here, it goes without saying that a material having translucency may be adopted as the material of the cladding mold 50 and the curing treatment may be performed by irradiating the cladding material 11 with the UV light E through the cladding mold 50. It is. Further, when a thermosetting resin is employed as the clad material 11, the curing process may be performed by heating.

  The clad material 11 is cured by the above curing process, and the clad 13 molded into a shape corresponding to the clad mold 50 in which the protrusions 51 are engraved is obtained. At this time, the clad material 11 tends to shrink as it hardens. However, since the curing process is performed in a state where the cladding mold 50 is in pressure contact with the cladding material 11, deformation in the main scanning direction of the cladding material 11 due to curing shrinkage is suppressed by the protrusions 51 of the cladding mold 50. The Therefore, when the clad material 11 is cured and shrunk, the pitch shift of the fine grooves 12 does not occur, and the clad 13 can be formed with high accuracy.

  Further, the clad material 11 is subjected to a curing process while being sandwiched between the clad support substrate 10 and the clad mold 50. For this reason, the clad 13 is not warped by curing shrinkage.

  On the other hand, since the shrinkage in the thickness direction of the clad material 11 is not suppressed, the thickness of the clad 13 obtained after the curing process is smaller than the thickness of the clad material 11 before the curing process. That is, as shown in FIG. 1D, the thickness of the clad 13 (the height of the upper surface of the partition wall 14 separating each narrow groove 12) is lower than the height of the upper surface of the spacer 40 by an amount X that is hardened and shrunk. .

  The shrinkage amount X can be adjusted by the material of the resin material and the curing conditions (in the case of the UV curing type, the UV light irradiation amount profile with respect to the time of UV light irradiation, and in the case of the thermosetting type, the temperature profile with respect to the time of heating). It is. For example, when the material and the curing conditions are adjusted so that the shrinkage rate is about 1%, if the height of the spacer 40 is 100 μm, the shrinkage amount X is 1 μm.

  Moreover, since the shrinkage | contraction of the optical transmission direction of the cladding material 11 is not suppressed, the cladding 13 deform | transforms into an optical transmission direction. However, since the length of the light guide plate 2 in the light transmission direction is adjusted at the time of division by dicing or the like as described later, there is no particular problem.

  As described above, the clad 13 including the plurality of narrow grooves 12 provided at a predetermined pitch can be accurately formed by the above-described manufacturing method without causing a pitch shift.

  Here, the structure of the narrow groove 12 will be described. The pitch of each narrow groove 12 is, for example, an interval determined by the resolution required by the light source 1 of the image forming apparatus to which the light guide plate 2 manufactured by this method is applied. That is, if the resolution is 200 dpi (dot par inch), the pitch of each narrow groove 12 is 127 μm (2.54 cm / 200), and if the resolution is 2400 dpi, the pitch of each narrow groove 12 is 10.58 μm (2. 54 cm / 2400).

  In addition, the width of the partition wall 14 that partitions each narrow groove 12 needs to be set to a width that optically isolates light transmitted by each core (described later) filled in each narrow groove 12. However, since the pitch of each narrow groove 12 is determined according to the resolution, when the width of each partition wall 14 increases, the width of the narrow groove 12 itself decreases (the width of the core decreases), and the amount of light that can be transmitted decreases. . For this reason, the width of the partition wall 14 is preferably as small as possible. The width of the partition wall 14 satisfying such conditions is, for example, 24 μm when the resolution is 200 dpi, and 2 μm when the resolution is 2400 dpi. In this case, the width of the narrow groove 12 is 103 μm when the resolution is 200 dpi, and 8.58 μm when the resolution is 2400 dpi. The height of each partition 14 is the same as the width of the narrow groove 12 so that the cross section of the light emitted from one end face of each core is square.

  In addition to the processing of the clad 13, as shown in FIG. 2 (a), on the core support substrate 20 made of quartz, glass or the like, by screen printing, spin coating, dripping or the like, thermosetting type or UV curing is performed. A layer of a plastic core material 21 made of a mold resin material or the like is formed. In the example of FIG. 2A, the core support substrate 20 is a light-transmitting glass substrate having a thickness of about 1 mm, and the core material 21 is a UV curable acrylic resin having a refractive index of 1.7. . At this time, the coating thickness of the core material 21 may be equal to or greater than the depth of the narrow groove 12 formed in the clad 13.

  Note that the surface of the core support substrate 20 to which the core material 21 is applied is preferably a smooth surface. Here, the smooth surface is a surface having sufficiently small surface roughness and flatness compared to the film thickness of the lower layer electrode of the light emitting element formed on the surface of the core described later.

  Next, as shown in FIGS. 2B and 2C, the surface of the clad 13 provided with the narrow grooves 12 is pressed against the core material 21 applied on the core support substrate 20. At this time, the core material 21 is filled in each narrow groove 12 of the clad 13, and the excess core material 21 is pushed out from the end of the clad 13 in the light transmission direction (longitudinal direction), and has a shape corresponding to the clad 13. Molded.

  At this time, the spacer 40 is disposed between the clad support substrate 10 and the core support substrate 20, and the distance W2 between the two substrates is set to the distance W1 when the clad support substrate 10 and the clad mold 50 are pressed. The intervals are the same as (shown in FIG. 1C).

  As shown in FIG. 1D, the upper surface of the partition wall 14 of the cladding 13 and the upper surface of the spacer 40 are not flush with each other, and the upper surface of the partition wall 14 is contracted by the contraction amount X toward the cladding support substrate 10 side. For this reason, when the spacer 40 is disposed between the two support substrates, a space (in the above example) corresponding to the contraction amount X is formed between the upper surface of the partition wall 14 (the lower surface in FIG. 2C) and the core support substrate 20. A gap of about 1 μm) can be provided, and there is no fear that the partition wall 14 and the core support substrate 20 come into contact with each other and the partition wall 14 is damaged.

  If the clad support substrate 10 includes the spacers 40, the distance W1 between the clad support substrate 10 and the clad mold 50 when the clad material 11 is molded, and the core support substrate when the core material 21 is molded. Since the interval W2 between 20 and the clad support substrate 10 is naturally the same interval, it is not necessary to manage these intervals, and the manufacturing becomes very easy. In addition, it is preferable that this press-contact is performed under vacuum, such as in a chamber, similarly to the molding of the clad material 11.

  Subsequently, with the clad support substrate 10 in pressure contact with the core support substrate 20 as described above, as shown in FIG. 2C, the core material 21 is irradiated with UV light E with a sufficient amount of light, The core material 21 is cured.

  As described above, since the glass substrate is used as the core support substrate 20, the UV light E can be applied to the core material 21 through the core support substrate 20. By this curing process, the cores 22 connected by a film-like layer (hereinafter referred to as a coating layer 23) corresponding to the space corresponding to the shrinkage amount X are obtained.

  In the curing process, the core material 21 contracts. However, since the deformation of the core 22 in the main scanning direction is suppressed by the narrow groove 12 (partition wall 14) of the clad 13, the pitch shift of each core 22 does not occur. Further, since the width of the core 22 is larger than the width of the partition wall 14, the shrinkage amount of the core material 21 is increased, and a gap is formed between the core 22 and the clad 13 (particularly, the front end portion of the partition wall 14). However, in the present embodiment, since the cores 22 are connected by the covering layer 23, the formation of such a gap can be suppressed.

  In addition, when the material which has translucency is employ | adopted for the material of the clad 13, you may irradiate the core material 21 with the UV light E through the clad 13, and may perform a hardening process, and thermosetting resin is used for the core material 21. When is adopted, the curing process may be performed by heating.

  Further, since the core material 21 is subjected to the curing process while being sandwiched between the core support substrate 20 and the clad support substrate 10 (cladding 13), the core 22 obtained after the curing process is not warped.

  After the core material 21 is cured, the core support substrate 20 is separated from the core 22 and the covering layer 23, whereby the light guide plate 2 including a plurality of cores 22 arranged at a predetermined pitch is obtained. The separation of the core support substrate 20 is performed, for example, by heating the core support substrate 20 from the surface where the core 22 is not formed, and reducing the bonding strength between the core support substrate 20 and the core 22 and the covering layer 23. Can do. For this heating, it is preferable to heat the bonding surface evenly, for example, by bringing a planar heat source such as a hot plate into contact with the core support substrate 20, and the heating temperature is the core 22, the coating layer 23, and the core support substrate. 20 is preferably set to a temperature at which the joint surface with the glass transition temperature Tg of the core material 21 is reached. Thereby, the core 22 and the coating layer 23 in the vicinity of the joint surface with the core support substrate 20 can be brought into a glass transition state, and the core support substrate 20 can be separated.

  In this way, the surfaces of the core 22 and the covering layer 23 exposed by the separation of the core support substrate 20 become a smooth surface 24 having smoothness equivalent to the smooth surface of the core support substrate 20.

  As described above, the surface on which the core of the core support substrate 20 is formed is preferably a smooth surface, but the heating temperature is a temperature at which only the core 22 and the coating layer 23 in the immediate vicinity of the bonding surface melt. As the (melting point), the surfaces of the core 22 and the coating layer 23 exposed by the separation of the core support substrate 20 may be once smoothed by bringing them into a molten state.

  As shown in FIGS. 3 and 4, organic light emitting elements 30 capable of emitting light for each position of the core 22 are formed at positions corresponding to the cores 22 of the light guide plate 2 configured as described above.

  First, as shown in FIG. 3A, a transparent lower electrode layer 34 made of ITO or the like is formed on the entire surface of the smooth surface 24 by sputtering or the like. Then, by performing photolithography and etching on the lower electrode layer 34, a pattern of the lower electrode 31 that is electrically separated at a position corresponding to each core 22 as shown in FIG. 3B is formed. The

  Thus, on the light-guide plate 2 in which each lower layer electrode 31 was formed, the organic light emitting layer 32 which consists of 8-quinolinol aluminum complex etc. is formed into a film by vapor deposition etc. (FIG.3 (c)). In this case, as shown in FIG. 4, the organic light emitting layer 32 is formed on one surface excluding a part of the uncovered region B for connection for supplying driving power to each lower layer electrode 31.

  As shown in FIGS. 3 and 4, the upper layer electrode 33 is formed on one surface by vapor-depositing aluminum or the like on the organic light emitting layer 32, and the light source 1 of the image forming apparatus including the light emitting element 30 is completed. In this configuration, a region where the lower layer electrode 31 and the upper layer electrode 33 overlap is a light emitting region. In the present embodiment, since the lower layer electrode 31 and the organic light emitting layer 32 are formed to a thickness of 0.1 μm and the upper layer electrode 33 is formed to a thickness of 0.2 μm, between the lower layer electrode 31 and the smooth surface 24. The formed step does not cause disconnection of the upper layer electrode 33 or short circuit between the lower layer electrode 31 and the upper layer electrode 33.

  By the way, in the light source 1 demonstrated above, since the said coating layer 23 has connected the adjacent core 22, the light emitted from the light emitting element 30 formed in the upper surface of the specific core 22 passes through the said coating layer 23. The phenomenon of leaking to adjacent cores (crosstalk) occurs. When such crosstalk is large, when light is emitted from a specific core, light is also emitted from an adjacent core. Therefore, a clear latent image is formed on the photoreceptor 500 shown in FIG. It becomes difficult to form. Therefore, it is necessary to make the structure capable of satisfactorily forming a latent image by reducing the thickness of the covering layer 23 and reducing the crosstalk. The thickness of the coating layer 23 that satisfies such conditions is, for example, 1 μm when the resolution is 200 dpi, and 0.1 μm when the resolution is 2400 dpi. For this reason, in the manufacturing method of the light guide plate 2, the material of the clad material 11, the coating film thickness, and the height of the spacer 40 are set so that the above-described shrinkage amount X satisfies this condition.

  As described above, according to the method for manufacturing the light guide plate 2 according to the present embodiment, the polishing step required in the conventional manufacturing method is unnecessary, and a good light guide plate 2 is obtained by a simple process. It becomes possible.

  In addition, according to the above manufacturing method, when the light source 1 of the image forming apparatus is configured by applying the light guide plate 2, the organic light emitting element 30 can be formed on the smooth surface 24, and thus the light emitting element 30 is formed. It is possible to reliably prevent the occurrence of defects such as disconnection and short circuit.

  The light source 1 configured as described above is, for example, divided into a desired size by dicing or the like, and then one end surface of the light guide plate 2 in the light transmission direction, like the conventional light source 100 shown in FIG. Is directed to the photoreceptor 500.

  Further, a light transmission means 400 such as a GI fiber lens is provided between the light guide plate 2 and the photosensitive member 500, and the light emitted from the one end surface is imaged on the surface of the photosensitive member 500. In addition, the reflective material 103 is vapor-deposited or apply | coated to the surface on the opposite side to the light emission end of each core 22 of the light-guide plate 2. As shown in FIG.

  According to the above configuration, light having a sufficient amount of light that is collected by the core 22 and emitted from one end surface of the core 22 is imaged on the photosensitive member 500, so that a high-resolution image can be formed. It is possible to print in a short time.

  In the above description, the clad 13 is molded by the clad mold 50, but the present invention is not limited to this. That is, in the manufacturing method according to the present embodiment, the clad 13 is restrained by the clad support substrate 10 and the core 22 is restrained by the core support substrate 20 until the light guide plate 2 is formed. This is essential, and this has the effect of suppressing deformation (pitch deviation and warpage) of the clad 13 and the core 22. Therefore, even when the clad 13 is formed on the clad support substrate 10 by, for example, photolithography and etching, the core 22 can be formed with high accuracy by employing the above-described method for forming the core 22. Is possible.

(Second Embodiment)
The manufacturing method for molding the core material 21 using the clad 13 as a molding die has been described above, but conversely, the clad 13 can be molded using the core 22 as a molding die. Therefore, in the second embodiment, a manufacturing method for forming the clad material 11 using the core 22 as a forming die will be described based on the schematic diagrams of FIGS. 5 and 6. In the present embodiment, parts having the same functions or structures as those in the first embodiment are denoted by the same reference numerals.

  First, as shown in FIG. 5A, a thermosetting or UV curable resin material is formed on a core support substrate 20 made of translucent quartz, glass or the like by screen printing, spin coating, dripping, or the like. A layer of the plastic core material 21 made of or the like is formed. In the example of FIG. 5A, as in the first embodiment, the core support substrate 20 is a transparent glass substrate having a thickness of about 1 mm, and the core material 21 is a UV having a refractive index of 1.7. A curable acrylic resin is used. Moreover, the surface to which the core material 21 of the core support substrate 20 is supplied is a smooth surface.

  Next, as shown in FIGS. 5B and 5C, a core mold 60 made of a material such as tungsten carbide (WC) is pressed against the core material 21 on the core support substrate 20. The joint surface of the core mold 60 with the core material 21 is provided with a plurality of grooves 61 for molding the core material 21 into a pattern composed of a plurality of protrusions provided at a predetermined pitch during pressure welding. Has been. Note that the end portions of the grooves 61 are opened to the outside so that the excess core material 21 is discharged from the outer edge portion of the core mold 60 in the process of the pressure contact. Further, in the present embodiment, unlike the first embodiment, the portions other than the groove 61 of the core mold 60 are flush with each other so that each core 22 has an independent pattern.

  The core material 21 is filled in each groove 61 of the core forming die 60 by the pressure contact. In this state, the core material 21 is cured by irradiating the core material 21 with a sufficient amount of UV light E through the core support substrate 20 as shown in FIG.

  As a result, the core material 21 is cured, and a pattern of a plurality of cores 22 is formed on the core support substrate 20 (FIG. 5D). In addition, since the curing process is performed in a state where the core mold 60 is pressed against the core material 21, no pitch deviation or warpage occurs in each core 22 as in the first embodiment.

  On the other hand, as shown in FIG. 6 (a), separately from the processing of the core 22, the thermosetting type or the like by screen printing, spin coating, dripping, etc. on the clad support substrate 10 made of silicon, quartz, glass or the like. A layer of the clad material 11 made of a UV curable resin material or the like is formed. Here, the clad support substrate 10 is a transparent glass substrate having a thickness of about 1 mm, and the clad material 11 is a UV curable epoxy resin having a refractive index of 1.5. Further, the point that the clad support substrate 10 includes the spacer 40 is the same as in the first embodiment.

  Next, as shown in FIGS. 6B and 6C, the surface of the core support substrate 20 on which the core 22 is formed is pressed against the clad material 11 so that the clad material 11 wraps around the core 22. Molded. At this time, the spacer 40 included in the clad support substrate 10 abuts on the core support substrate 20, and limits the interval between the core support substrate 20 and the clad support substrate 10 to an interval at which each core 22 does not contact the clad support substrate 10. For this reason, there is no possibility that each core 22 contacts the clad support substrate 10 and is damaged.

  As described above, with the core 22 being pressed against the clad material 11, the clad material 11 is irradiated with the UV light E with a sufficient amount of light, and the clad material 11 is cured. As described above, since the core support substrate 20 and the core 22 have translucency, the UV light E may be irradiated through the core support substrate 20.

  The clad material 11 is cured by the curing process, and the clad 13 is obtained in a state where the clad material 11 wraps around three sides of the core 22 (three sides excluding the surface on the core support substrate 20 side). Even in this hardening process, the clad material 11 tends to be deformed by hardening shrinkage, but each core 22 is restrained by the core support substrate 20, so that no pitch shift occurs in each core 22. In addition, since the clad material 11 is cured while being sandwiched between the clad support substrate 10 and the core support substrate 20, the clad 13 is not warped.

  At this time, the clad material 11 is cured and shrunk, but unlike the state shown in FIG. 1D, the core 22 exists between the partition walls 14 of the clad 13. For this reason, the clad material 11 is in a state where the contact surface with the core 22 is constrained, and a step corresponding to the shrinkage amount X described above does not occur. Even when the clad 13 is deformed due to hardening shrinkage, as shown in the enlarged portion of FIG. 6D, a gentle slope is formed in which only the central portion in the width direction of the partition wall 14 of the clad 13 is shrunk. Therefore, a step that causes a problem in the light emitting element 30 formed on the upper surface is not formed.

  After the core material 21 is cured, the core support substrate 20 is separated from the core 22 to obtain the light guide plate 2 including a plurality of cores 22 arranged at a predetermined pitch (FIG. 6D). ). The separation of the core support substrate 20 may be performed by heating the core support substrate 20 as in the first embodiment.

  Each core 22 of the light guide plate 2 configured as described above is divided and applied to the image forming apparatus after the organic light emitting element 30 capable of emitting light is formed for each position of the core 22. Since this is the same as that of the embodiment, description thereof is omitted here.

  As explained above, in the manufacturing method according to the present embodiment, the core material 21 and the cladding material 11 can be formed with high accuracy while suppressing deformation when the core material 21 and the cladding material 11 are cured and contracted, and The polishing step required in the conventional manufacturing method is unnecessary, and the light guide plate 2 can be obtained by a simple process.

  Moreover, according to the said manufacturing method, since the organic light emitting element 30 is formed on a smooth surface, it can prevent that the defect of a disconnection and a short circuit at the time of forming the light emitting element 30 generate | occur | produces.

  The manufacturing method according to the present invention enables a light guide plate provided with a plurality of cores to be formed with high accuracy by a simple process compared to the prior art, and the light guide plate obtained by this manufacturing method has a high resolution. It is useful as a light source or the like of an image forming apparatus that enables printing.

The schematic diagram which shows the manufacturing method of the light-guide plate of this invention. The schematic diagram which shows the manufacturing method of the light-guide plate of this invention. The schematic diagram which shows the manufacturing method of the light source of the image forming apparatus to which the light-guide plate of this invention is applied. The top view of the light source of the image forming apparatus to which the light-guide plate of this invention is applied. The schematic diagram which shows the manufacturing method of the light-guide plate of this invention. The schematic diagram which shows the manufacturing method of the light-guide plate of this invention. The perspective view which shows the conventional light source applied to the image forming apparatus. The schematic diagram which shows the manufacturing method of the conventional light-guide plate. The schematic diagram which shows the manufacturing method of the conventional light-guide plate. The figure which shows the defect by the level | step difference of the conventional light source.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Light guide plate 10 Clad support board 12 Narrow groove 13 Cladding 14 Partition 20 Core support board 22 Core 23 Cover layer 24 Smooth surface 30 Organic light emitting element (light emitting element)
Reference Signs List 31 Lower layer electrode 32 Organic light emitting layer 33 Upper layer electrode 100 Light source 101 Substrate 102 Core 102a Cladding 103 Reflector 200 Light guide plate 300 Light emitting element 400 Optical transmission means 500 Photoconductor

Claims (11)

Forming a plate-like clad having a plurality of narrow grooves on the clad support substrate;
On the core support substrate, supplying a plastic core material having a higher refractive index than the clad and having translucency;
Pressing the surface of the clad with the narrow groove to the core material;
Curing the core material in a state where the clad is pressed against the core material, and forming a portion corresponding to the narrow groove as a core;
Separating from the core support substrate and the cured core material;
A method for producing a light guide plate, comprising: Forming the cladding comprises:
Supplying a plastic clad material on the clad support substrate;
Pressure-contacting a cladding mold having a plurality of protrusions corresponding to the narrow grooves to the cladding material;
Curing the clad material in a state where the mold for clad is in pressure contact with the clad material, and forming the clad having the narrow grooves corresponding to the ridges;
The manufacturing method of the light-guide plate of Claim 1 which has these.   The guide according to claim 1, wherein a spacer is provided on the clad support substrate to limit a distance between the clad support substrate and the core support substrate when the clad is pressed against the core material to a specific distance. Manufacturing method of light plate. Forming a plurality of cores that are translucent protrusions on a core support substrate;
Supplying a plastic clad material having a lower refractive index than the core on the clad support substrate;
Pressing the surface of each of the core support substrates with the cores against the clad material;
Curing the clad material in a state where the cores are in pressure contact with the clad material, and forming a clad that encloses each core except for the core support substrate surface;
Separating the core support substrate and the cores;
A method for producing a light guide plate, comprising: Forming the core comprises:
Supplying a core material having plasticity on the core support substrate;
A step of pressing a core mold having a plurality of narrow grooves corresponding to the protrusions against the core material;
Curing the core material in a state where the core mold is pressed against the core material, and forming a portion corresponding to the narrow groove as a core;
The manufacturing method of the light-guide plate of Claim 4 which has these.   6. The spacer according to claim 4, wherein a spacer is provided on the clad support substrate to limit a distance between the core support substrate and the clad support substrate when the core is pressed against the clad material to a specific distance. Manufacturing method of light guide plate.   The method for manufacturing a light guide plate according to claim 3 or 6, wherein the spacer is a convex portion formed integrally with the clad support substrate.   The method for manufacturing a light guide plate according to claim 1, wherein a surface on which the core of the core support substrate is formed is a smooth surface. A plate-like clad provided on the upper surface with a plurality of narrow grooves provided on the clad support substrate;
A core made of a translucent material having a higher refractive index than the cladding and filled in the narrow groove;
A spacer provided on the clad support substrate, the upper surface of which is located at the same height as the upper surface of the core;
A light guide plate characterized by comprising:   The light guide plate according to claim 9, wherein the spacer is a convex portion formed integrally with the clad support substrate. The light guide plate according to claim 9 or 10, wherein the narrow grooves are provided at a predetermined pitch.

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