JP2012113280A - Wire grid polarizer and optical sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire grid polarizer for an optical sensor capable of improving productivity of an optical sensor while maintaining optical characteristic.SOLUTION: A wire grid polarizer (1) of the invention is a wire grid polarizer (1) used in an optical sensor including a projector disposed to emit projection light entering a projection polarization unit (11) of the wire grid polarizer (1) and a light receiver disposed to receive measurement light transmitted through a receiver polarization unit (12) of the wire grid polarizer (1). The projection polarization unit (11) and the receiver polarization unit (12) with different transmission axis directions to each other are made on a surface of one base material.

Description

  The present invention relates to a wire grid polarizer for an optical sensor having a light projecting polarization unit and a light receiving polarization unit having different transmission axis directions. Moreover, it is related with the optical sensor using this.

  Some retro-reflective photoelectric sensors and biometric authentication devices have a light projecting polarizer in the projector and a light receiving polarizer in the light receiver in order to improve detection accuracy. In many photosensors having a polarizer, a projector and a photoreceiver are placed close to each other from the viewpoint of miniaturization of the device and improvement of sensing accuracy. For example, as in the photosensor 201 shown in FIG. The different light projecting polarizer 202 and light receiving polarizer 203 are arranged so as to be substantially on the same plane (in FIG. 7, on one surface of the housing of the optical sensor 201) from the viewpoint of device design. is doing. When manufacturing such an optical sensor, each of the light-projecting polarizer 202 and the light-receiving polarizer 203 having different transmission axis directions is incorporated, but the polarization axis direction of the polarizer is discriminated by normal light. In order to prevent erroneous incorporation, it is necessary to devise measures such as changing the shapes of the light projecting polarizer 202 and the light receiving polarizer 203. As a result, the number of parts increases, which causes an increase in cost.

  As a method for solving such a problem, for example, a technique disclosed in Patent Document 1 has been proposed. The outline of this technique is as follows. First, polarization is performed so that a pair of diagonal lines 301 a of the light projecting polarizer 301 and a pair of diagonal lines 301 b of the light receiving polarizer 302 are positioned on a straight line, and their opposite corners are two rectangles joined by the connecting portion 303. The child 304 is cut (see FIG. 8A). Next, one of the two quadrilaterals connected by the connecting portion 303 is rotated by 90 degrees in the plane direction about the connecting portion 303, so that the light transmitting polarizer 301 and the light receiving unit having different transmission axis directions are received. It is set as the polarizer 302 for use (refer FIG. 8B). And the polarizer produced in this way is incorporated in the optical sensor. However, this technique places a limit on the shape design of the polarizer. Moreover, since a thick polarizer is bent and incorporated in the housing of the optical sensor, the working efficiency is lowered. Further, since the polarizer is rotated (bent) around the connecting portion 303, the periphery of the connecting portion 303 is curved and raised, and the projection light is emitted without passing through the light projecting polarizer 301, or for receiving light. Problems such as a decrease in sensing accuracy of the optical sensor, such as measurement light entering the light receiver without passing through the polarizer 302, are likely to occur.

JP 7-220590 A

  As described above, it has been difficult for the conventional technology to improve the productivity of the optical sensor without reducing the detection accuracy of the optical sensor. The present invention has been made in view of the above points, and an object of the present invention is to provide a wire grid polarizer for an optical sensor capable of improving the productivity of the optical sensor while ensuring optical characteristics. To do.

  The wire grid polarizer of the present invention includes a projector disposed to emit projection light that enters the light projecting polarization section of the wire grid polarizer, and a measurement that passes through the light receiving polarization section of the wire grid polarizer. A wire grid polarizer used in an optical sensor provided with a light receiver arranged to receive light, the light projecting polarizing section having different transmission axis directions on the same base material surface, and A light receiving polarization section is built in.

  With such a configuration, since the light projecting polarizing section and the light receiving polarizing section are formed on the same base material surface, it is possible to simplify the process of incorporating into the optical sensor and prevent erroneous assembly. Further, since the light projecting and light receiving polarizing portions having different transmission axis directions are provided on the same base material surface, processing such as bending the polarizer becomes unnecessary. As a result, erroneous detection due to light leakage from the polarizer can be prevented, so that the detection accuracy of the optical sensor does not deteriorate.

  The light projecting polarizing section includes a first portion in which the concavo-convex structure extends in the first direction at a predetermined interval in a cross section perpendicular to the direction in which the concavo-convex structure extends (hereinafter referred to as “cross-sectional view”). And a first conductor provided so as to be unevenly distributed on one side surface of the convex portion of the first concavo-convex structure portion, and the light receiving polarization portion has a concavo-convex structure. A second concavo-convex structure portion extending in a second direction different from the first direction at a predetermined interval, and a second concavo-convex structure portion provided so as to be unevenly distributed on one side surface of the second concavo-convex structure portion. And a conductor.

  With such a configuration, since the conductor is unevenly distributed on one side surface of each concavo-convex structure portion, the polarization separation characteristics of each polarization portion can be improved.

  Moreover, the said uneven structure can be comprised with the base material which consists of resin.

  With such a configuration, a roll process is possible, so that the productivity of the wire grid polarizer can be increased. Further, the wire grid polarizer can be curved and used without causing problems such as light leakage, and the weight can be reduced.

  Further, in the cross section perpendicular to the direction in which the concavo-convex structure extends, the concavo-convex structure has a substantially sinusoidal shape, and passes through the top of the convex part of the concavo-convex structure, along the convex axis along the standing direction of the convex part. On the other hand, the conductor axis along the standing direction of the conductor through the top of the conductor can be varied.

  With such a configuration, the contact area between the conductor and the concavo-convex structure can be increased, so that peeling of the conductor can be prevented, and it becomes easy to form a conductor having a high height. Separation characteristics can be improved.

  Further, a region having no concavo-convex structure connected to the concavo-convex structure forming the light projecting polarization part or the light receiving polarization part at the boundary between the light projecting polarization part and the light receiving polarization part on the substrate surface It can be.

  With such a configuration, there is no uneven structure connected to the boundary between the light projecting polarizing section and the light receiving polarizing section, and when the paint is applied to the substrate surface of the boundary, the paint or the like is a capillary phenomenon. The possibility of flowing into the concavo-convex structure and damaging the light projecting polarizing section or the light receiving polarizing section can be reduced.

  Further, the concavo-convex structure can be formed in the same process using a metal stamper produced from a mold having a region provided with a concavo-convex structure corresponding to the concavo-convex structure on the same surface.

  With such a configuration, the concavo-convex structure of the wire grid polarizer can be formed in the same process, and therefore the productivity of the wire grid polarizer can be increased. In addition, since the extending direction of the concavo-convex structure can be determined at the time of producing the metal stamper, it is possible to suppress variations in the extending direction of the concavo-convex structure of each polarizing portion during the preparation of the concavo-convex structure on the substrate surface, and the manufactured product Variation in performance can be reduced.

  Further, the mold can be produced by joining a plurality of plates having a concavo-convex structure on the surface.

  With such a configuration, it becomes easy to produce multiple regions with different concavo-convex structure extending directions in the same plane of the mold, customize the wire grid polarizer according to the final product, and shorten the mold production period. It becomes possible.

  Moreover, the said casting_mold | template can be produced by bonding the several plate | version | printing, after bonding the uneven | corrugated structure surface of the several plate | version | printing which has an uneven | corrugated structure on the surface to a low-adhesion adhesive sheet.

  With such a configuration, it becomes easy to fix a plurality of plates having a concavo-convex structure, and workability at the time of producing a mold can be improved.

  Further, in the light projecting polarization unit or the light receiving polarization unit, variation in the extending direction of the first conductor or variation in the extending direction of the second conductor is within ± 3 degrees. be able to.

  With such a configuration, the polarization performance can be improved and the detection accuracy of the optical sensor can be increased.

  Further, the first conductor and the second conductor can be embedded with an adhesive resin.

  With such a configuration, since the conductor is embedded with the adhesive substance, it is possible to prevent the wire grid polarizer from being damaged.

  In addition, a boundary between the light projecting polarization unit and the light receiving polarization unit can be set to a low transmittance.

  Such a configuration makes it easy to visually recognize the boundary portion, so that it is easy to align the light sensor's light projector with the light projecting polarization unit and the light sensor's light receiver and light receiving polarization unit. It becomes. Further, it becomes easy to separate the light projecting light path and the light receiving light path inside the optical sensor device, and the projection light can be prevented from directly entering the light receiver inside the device.

  Moreover, a substrate can be provided on the base material. By providing the substrate, the strength of the wire grid polarizer can be improved.

  The extending direction of the polarization axis of the light projecting polarization unit and the extending direction of the polarization axis of the light receiving polarization unit are orthogonal to each other, and the extending direction of the polarization axis of the light projecting polarization unit or The extending direction of the polarization axis of the light receiving polarization unit may intersect the MD direction of the substrate at 45 degrees.

  With such a configuration, it becomes possible to place the evaporation source in the MD direction of the substrate in the manufacturing process, so that the production efficiency can be increased.

  The wire grid polarizer of the present invention includes a projector disposed to emit projection light that enters the light projecting polarization section of the wire grid polarizer, and a measurement that passes through the light receiving polarization section of the wire grid polarizer. A wire grid polarizer used in an optical sensor including a light receiver arranged to receive light, wherein a part of a polarization unit including a conductor extending in a predetermined direction has a predetermined shape The cut-out member is separated into a cut-out member and a cut-out source member having an opening corresponding to the cut-out member, and the extending direction of the conductor included in the cut-out member and the cut-out source member are Rotating the cut-out member or the cut-out member so that the extending direction of the conductor has a predetermined angle, and fixing the cut-out member to the opening of the cut-out member Yo Wherein the formed the projection beam polarizing portions and provided with the light receiving polarizing unit.

  With such a configuration, it is possible to accurately control the polarization direction of transmitted light that passes through the light projecting polarization unit and the light receiving polarization unit. Furthermore, since the member cut out after rotating is fixed to an opening part, dimension adjustment etc. are easy.

  Further, the cut-out member may have a n-fold symmetry shape, and a rotation angle of the cut-out member or the cut-out source member may be 360 ° / n.

  The optical sensor of the present invention uses the wire grid polarizer described above.

  Such an arrangement makes it possible to simultaneously incorporate the polarizers that are incorporated one by one at the time of manufacturing the optical sensor at the same time, thereby simplifying the process and preventing erroneous incorporation. In addition, since the light projecting polarizing section and the light receiving polarizing section having different transmission axis directions are provided on the same substrate surface, it is not necessary to bend the polarizer or the like, and it is easy to ensure the optical characteristics of the polarizer. . Thereby, it is possible to prevent occurrence of false detection due to light leakage of the polarizer.

  In addition, a light sensor projector is provided on the opposite side of the substrate surface of the wire grid polarizer in which the light projecting polarization unit and the uneven structure of the light receiving polarization unit and the conductor are provided on the substrate surface. And a light receiver are preferably provided.

  With such an arrangement, the optical sensor can maintain excellent sensing accuracy even if the in-plane phase difference of the substrate changes when the substrate and the substrate of the wire grid polarizer are provided.

  By using the wire grid polarizer at the time of manufacturing an optical sensor having a light projecting polarizer and a light receiving polarizer, the light projecting polarizer and the light receiving polarizer are incorporated at the same time. Compared with the case of incorporation, the incorporation process of the polarizer can be simplified and erroneous incorporation can be prevented. In addition, since the light projecting and light receiving polarizing portions having different transmission axis directions are provided on the same base material, it is not necessary to perform processing such as bending the polarizer, and it becomes easy to secure the optical characteristics of the polarizer. Thereby, it is possible to prevent the occurrence of the problem of false detection due to the light leakage of the polarizer.

2 is a schematic diagram illustrating a configuration of a wire grid polarizer according to Embodiment 1. FIG. 3 is a schematic cross-sectional view showing a configuration of a wire grid polarizer according to Embodiment 1. FIG. 2 is a schematic diagram illustrating a configuration of a wire grid polarizer according to Embodiment 1. FIG. 6 is a schematic cross-sectional view illustrating a manufacturing process of the metal stamper according to Embodiment 1. FIG. 1 is a schematic diagram illustrating a configuration of a photosensor according to Embodiment 1. FIG. It is a schematic diagram which shows a mode that the optical sensor which concerns on Embodiment 1 detects an object. It is a schematic diagram which shows the structure of an optical sensor. It is a schematic diagram which shows the preparation process of the polarizer for optical sensors. 6 is a schematic diagram illustrating one configuration of a wire grid polarizer according to Embodiment 2. FIG. 6 is a schematic diagram illustrating another configuration of a wire grid polarizer according to Embodiment 2. FIG. 6 is a diagram illustrating a method for manufacturing a wire grid polarizer according to Embodiment 2. FIG.

(Embodiment 1)
Embodiments of the invention will be specifically described below.
<Wire grid polarizer>
The wire grid polarizer of the present embodiment allows the projection light emitted from the projector to enter the light projecting polarization section of the wire grid polarizer, and enters and transmits the light receiving polarization section of the wire grid polarizer. It is used for an optical sensor provided with a light receiver so as to receive measurement light. This wire grid polarizer is a light grid polarizer for an optical sensor, wherein a light projecting polarization unit and a light receiving polarization unit having different transmission axis directions are formed on the same base material surface. This wire grid polarizer has one or more independent light projecting polarization sections and light receiving polarization sections.

  FIG. 1 shows an example of a wire grid polarizer 1 having a light projecting polarizing section 11 and a light receiving polarizing section 12 on the surface of a base material 13. In FIG. 1, a line extending in the horizontal direction (X direction) in the light projecting polarization unit 11 and a line extending in the vertical direction (Y direction) in the light receiving polarization unit 12 indicate a thin wire conductor, and the wire In the light projection polarization section 11 or the light reception polarization section 12 of the grid polarizer 1, it is shown that a plurality of thin wire conductors are provided substantially parallel (in a stripe pattern) to each other. The wire grid polarizer 1 having a conductor having such a structure can transmit polarized light in a direction (transmission axis direction) perpendicular to the direction in which the conductor extends. The wire grid polarizer 1 is capable of transmitting two types of polarized light whose polarization directions are 90 ° different between the light projecting polarization unit 11 and the light receiving polarization unit 12 and whose polarization directions are different by 90 °. Therefore, it can be used for an optical sensor using two types of polarized light.

  FIG. 2 is a partial cross-sectional schematic diagram of the light projecting polarizing section 11. Note that the cross section shown in FIG. 2 is a cross section in a direction perpendicular to the direction in which the conductor extends. In the wire grid polarizer 1, the light projecting polarizing section 11 has a concavo-convex structure 22 formed on the base material 13 and a conductor 21 formed on the concavo-convex structure 22. In the light projecting polarization section 11, the concavo-convex structure 22 (first concavo-convex structure) extends in a predetermined direction (first direction, depth direction in FIG. 2, X direction) at a predetermined interval (pitch). Yes. Further, the conductor 21 is provided so as to be unevenly distributed on one side surface of the convex portion of the concavo-convex structure 22. That is, in the light projecting polarizing section 11, the conductor 21 extends in a direction parallel to the direction in which the concavo-convex structure 22 extends.

  The light receiving polarization unit 12 is the same as the light projecting polarization unit 11 except for the extending direction of the conductor 21 and the concavo-convex structure 22. In the light receiving polarization section 12, the concavo-convex structure 22 (second concavo-convex structure) extends in a predetermined direction (second direction, Y direction) with a predetermined interval (pitch). Further, the conductor 21 is provided so as to be unevenly distributed on one side surface of the convex portion of the concavo-convex structure 22 and extends in a direction parallel to the direction in which the concavo-convex structure 22 extends.

  Thus, by extending the conductor 21 in two different directions (the first direction and the second direction), the polarized light that transmits through the light projecting unit and the polarized light that transmits through the light receiving unit are made different. Therefore, the detection accuracy of the optical sensor can be improved. In addition, since most of the optical sensors have a transmission axis direction of the light projecting polarization unit 11 and a transmission axis direction of the light reception polarization unit 12 substantially orthogonal to each other, the first direction and the second direction are approximately orthogonal to each other. It is preferable that In addition, since the light projecting polarization unit 11 and the light receiving polarization unit 12 are highly flexible according to the optical design of the optical sensor, the light projecting polarization unit 11 and the light receiving polarization unit 12 are respectively disposed on the same base material. You can have one or more. For example, as shown in FIG. 3, the light projecting polarizing section 11 can be provided at four locations and the light receiving polarizing section 12 can be provided at one location.

  The polarization performance and the optical sensor are such that the extending direction of the conductor is within ± 3 degrees at any three points in the same polarizing section (for example, the light projecting polarizing section 11 or the light receiving polarizing section 12). It is preferable from the viewpoint of sensing accuracy when used.

  The boundary part 14 between the light projecting polarizing part 11 and the light receiving polarizing part 12 can be made to have a low transmittance with respect to light of a predetermined wavelength by covering it with a light transmissive conductor or a light transmissive resin. . Thereby, since the boundary can be easily visually recognized, alignment between the light projector and the light projecting polarization unit 11 and alignment between the light receiver and the light reception polarization unit 12 are facilitated. Further, it becomes easy to separate the light projecting light path and the light receiving light path inside the optical sensor device, and the projection light can be prevented from directly entering the light receiver inside the device. The low transmittance means that the transmittance of light of a predetermined wavelength is lower than the transmittance of light at a predetermined wavelength of the light projecting polarization unit 11 and the light receiving polarization unit 12. The transmittance when entering natural light is preferably 25% or less, and more preferably 15% or less. When the boundary portion 14 between the light projecting polarizing portion 11 and the light receiving polarizing portion 12 is covered with the hardly transmissive conductor or the hardly transmissive resin, the surface of the base material 13 of the boundary portion 14 is used for the light projecting. It is preferable that there is no concavo-convex structure continuous with the concavo-convex structure forming the polarizing part 11 or the light-receiving polarizing part 12. As a result, when a paint containing a light-transmitting resin is applied to the substrate surface at the boundary, the paint can flow into the concavo-convex structure by capillary action, and can impinge on the light projecting polarizing part 11 or the light receiving polarizing part 12. Can be lowered.

  In addition, it is preferable in terms of optical characteristics that the conductor 21 is selectively provided on one side surface of the convex portion of the concavo-convex structure 22 provided on the base material 13. Moreover, it is preferable that at least a part of the conductor 21 exists above the top of the convex portion of the concavo-convex structure 22. By providing the conductor 21 so as to extend upward from the top of the convex portion, the polarization separation characteristics can be improved and the loss of light can be reduced. Further, on the surface perpendicular to the direction in which the concavo-convex structure 22 extends (the cross section shown in FIG. 2, hereinafter referred to as “sectional view”), the side surface of the conductor 21 above the top of the convex portion is in the vertical direction. It is preferable that the shape is inclined and the shape is tapered and has a sharp shape resembling a triangle. By making the shape of the conductor 21 above the top of the convex portion in a sectional view sharp, an adhesive resin is provided on the structure of the conductor 21 of the wire grid polarizer 1, and the conductor is wrapped with the adhesive resin. It is possible to suppress a decrease in parallel transmittance when buried. Moreover, it is preferable that the concavo-convex structure 22 has a substantially sinusoidal shape in a sectional view (see FIG. 2). Thereby, the highest part of the convex part of the concavo-convex structure 22 provided in the base material 13 while the shape of the conductor 21 above the top part of the convex part in a sectional view is made sharp by oblique vapor deposition and isotropic etching. The thickness of the conductor (the thickness in the direction parallel to the main surface of the base material 13) with respect to the thickness of the convex portion at a position lower by 1/3 in the height direction can be the same or more. Moreover, by this, the parallel transmittance | permeability and the fall of a polarization degree at the time of embedding the conductor 21 of the wire grid polarizer 1 with adhesive resin can be suppressed. Moreover, it is preferable that the convex part axis | shaft which passes along the top part of a convex part and follows the standing direction of a convex part and the conductor axis | shaft which passes along the top part of the conductor 21, and stands along the standing direction are different (it does not overlap). Thereby, since the contact area of the conductor 21 and the uneven structure 22 can be increased, peeling of the conductor 21 can be prevented. Moreover, since the thickness (height) of the conductor 21 can be sufficiently increased, the polarization separation characteristics of the wire grid polarizer 1 can be improved.

<Base material>
As the base material 13 constituting the concavo-convex structure 22, for example, an inorganic material such as glass or a resin material can be used. Among these, the use of a resin material is preferable because there are merits such that a roll process can be performed and the wire grid polarizer 1 can have flexibility (flexibility). Examples of the resin that can be used for the substrate 13 include polymethyl methacrylate resin, polycarbonate resin, polystyrene resin, cycloolefin resin (COP), crosslinked polyethylene resin, polyvinyl chloride resin, polyacrylate resin, polyphenylene ether resin, Amorphous thermoplastic resins such as modified polyphenylene ether resin, polyetherimide resin, polyether sulfone resin, polysulfone resin, polyether ketone resin, polyethylene terephthalate (PET) resin, polyethylene naphthalate resin, polyethylene resin, polypropylene resin , Crystalline thermoplastic resins such as polybutylene terephthalate resin, aromatic polyester resin, polyacetal resin and polyamide resin, and purple such as acrylic, epoxy and urethane Line (UV) curable resins and thermosetting resins. In addition, a UV curable resin or a thermosetting resin and an inorganic material such as glass, the thermoplastic resin, a triacetate resin, or the like can be used in combination, or these materials can be used alone. Further, a thin film for improving the adhesion between the base material 13 and the conductor 21 constituting the concavo-convex structure 22 may be provided on the surface of the concavo-convex structure 22.

  Moreover, the base material 13 by which the uneven structure 22 was previously provided in the surface in which the conductor 21 is formed can be used as the base material 13. FIG. Further, as described above, it is preferable that the concavo-convex structure 22 made of the base material 13 has a substantially sinusoidal shape in a cross-sectional view perpendicular to the direction in which the concavo-convex structure extends. Moreover, the base material 13 should just be substantially transparent in the target wavelength range. It should be noted that extending in a predetermined direction is not limited as long as the concavo-convex structure 22 extends substantially in the predetermined direction, and each concavo-convex structure of the concavo-convex structure 22 does not have to extend strictly in parallel. .

  The manufacturing method of the base material 13 which has the uneven structure 22 on the surface is not specifically limited. For example, a manufacturing method according to Japanese Patent No. 4147247 filed by the present applicant can be used. In this manufacturing method, using a metal stamper having a concavo-convex structure produced using an interference exposure method, the concavo-convex structure is thermally transferred to a thermoplastic resin, and parallel to the extending direction of the concavo-convex structure of the thermoplastic resin provided with the concavo-convex structure. Uniaxial stretching of the free end in any direction. As a result, the pitch of the concavo-convex structure transferred to the thermoplastic resin is reduced, and a resin plate (stretched) having a fine concavo-convex structure is obtained. Subsequently, a metal stamper having a fine concavo-convex structure is produced from the obtained resin plate having a fine concavo-convex structure (stretched) using an electrolytic plating method or the like. By using this metal stamper to transfer and form a fine concavo-convex structure on the surface of the base material, a base material having a concavo-convex structure can be obtained.

  In this case, the resin plate having a plurality of fine concavo-convex structures (stretched) is cut into a predetermined size in the extending direction of the predetermined concavo-convex structure and bonded to thereby extend the concavo-convex structure on the same plate. A resin plate having regions with different directions can be produced. For this reason, the metal stamper which has the area | region where the extension direction of an uneven | corrugated structure mutually differs on the same stamper using an electrolytic plating method etc. can be produced.

  Specifically, the flat mold plate 31 on which a plurality of resin plates having a fine concavo-convex structure (stretched) can be arranged has excellent affinity with the adherend and low adhesion that does not contaminate the adherend by peeling. -The low-adhesion adhesive sheet 32 which has an easily peelable adhesive layer on both surfaces is bonded (refer FIG. 4A). Then, resin plates (stretched) 33a and 33b having a plurality of fine concavo-convex structures cut out to a predetermined size in the extending direction of the predetermined concavo-convex structure are arranged in a predetermined arrangement, and bubbles are formed on the mold plate. The uneven structure surface is bonded to the low-adhesive pressure-sensitive adhesive sheet 32 so as to prevent mixing of the surface (see FIG. 4B). Here, in order to produce the metal stamper for the wire grid polarizer 1 shown in FIG. 1, the resin plates 33a and 33b are arranged so that the concavo-convex structures of the resin plate 33a and the resin plate 33b are substantially orthogonal to each other. That is, the uneven structure of the resin plate 33a corresponds to the uneven structure of the light projecting polarizing portion 11 of the wire grid polarizer 1, and the uneven structure of the resin plate 33b is the uneven structure of the light receiving polarizing portion 12 of the wire grid polarizer 1. Corresponds to the structure. Thereafter, if necessary, the gap between the resin plates (stretched) 33a and 33b having a plurality of fine concavo-convex structures is filled with the bonding resin 34, and a curing process is performed by a predetermined method for bonding. Further, the plate 35 having the adhesive layer is bonded to the opposite side of the surface having the concavo-convex structure of the resin plates (stretched) 33a and 33b (see FIG. 4C). By bonding the concavo-convex structure surfaces of the resin plates (stretched) 33a, 33b having a fine concavo-convex structure to the low-adhesive pressure-sensitive adhesive sheet 32, the bonding resin 34 has a concavo-convex structure of the resin plates 33a, 33b by capillary action. The possibility of attack can be lowered. Although there is no restriction | limiting in particular as resin 34 for joining, When using a hardening type | mold, in order to prevent the deformation | transformation of the edge part of resin plate 33a, 33b and a change of an arrangement position, the volume shrinkage rate before and behind hardening is 10%. The volume shrinkage is preferably 5% or less. Further, if the viscosity is 1000 cps (temperature 25 degrees) or more, it is possible to reduce the possibility that the bonding resin 34 invades the uneven structure during bonding. Examples of the curable bonding resin 34 include photo-curing resins such as acrylic, epoxy, and urethane. If necessary, curing treatment (light irradiation) may be performed in a nitrogen atmosphere. preferable. After the bonding resin 34 is cured, it is peeled off from the pressure-sensitive adhesive sheet 32 on the mold plate 31 so that a resin plate having regions where the extending directions of the concavo-convex structure are different from each other on the same plate can be produced (FIG. 4D), by using an electrolytic plating method or the like, a metal stamper having regions where the extending directions of the concavo-convex structure are different from each other can be manufactured on the same stamper.

  In addition, there is a method of forming and using a fine concavo-convex structure on a silicon substrate or the like by applying photolithography for semiconductor manufacturing. In this method, for example, a silicon substrate on which a fine concavo-convex structure is formed is bonded using the same method as described above, and a resin plate having a fine concavo-convex structure on the surface using the bonded silicon substrate as a mold Is made. Then, a metal stamper having a fine concavo-convex structure is produced from the resin plate using an electrolytic plating method or the like.

<Conductor>
The conductor 21 is provided on the surface of the substrate 13 having the concavo-convex structure 22. As described above, when the conductor 21 is provided on the base material 13 having the concavo-convex structure 22 formed on the surface, the conductor 21 is provided so as to be in contact with one side surface of the convex portion and the upper portion to extend upward from the top portion of the convex portion. Is preferred.

  The conductor 21 is formed in a straight line with a predetermined interval (period) substantially parallel to the convex portion of the concavo-convex structure 22 extending in a predetermined direction, and the period of the linear conductor 21 is visible. When the wavelength is smaller than the wavelength of the light, the polarization component that vibrates in parallel with respect to the conductor 21 is reflected, and the vertical polarization component is transmitted. As the conductor 21, aluminum, silver, copper, platinum, gold, or an alloy containing any of these can be used, and can be formed by an oblique sputtering method or an oblique evaporation method. In particular, it is preferable to form the conductor 21 using aluminum or silver because the absorption loss of visible light can be reduced.

  In general, a polarizer having a wire grid structure exhibits better polarization characteristics in a wider wavelength band as the distance (pitch) between the conductors 21 is smaller. When the conductor 21 is in contact with air (refractive index 1.0) and is not embedded with an adhesive substance, the pitch of the conductor 21 is set to ¼ to ３ of the wavelength of the target light. However, when the conductor is embedded with the adhesive resin, the influence of the refractive index of the adhesive resin is taken into consideration, and the wavelength of the target light is 1/5. More preferably, the pitch is ˜¼.

  In many cases, the wavelength of light used in the optical sensor is 600 nm or more. Therefore, in the case of a wire grid polarizer having a pitch of 150 nm or less, there is no practical problem in terms of optical characteristics even if it is embedded with an adhesive resin in order to prevent damage to the conductor. However, when a wire grid polarizer having high polarization characteristics and high damage resistance is required, it is effective not only to reduce the pitch but also to optimize the shape of the conductor in cross-sectional view. Become.

  As described above, the preferred shape of the conductor in the case of embedding with an adhesive resin is a position that is 1/3 lower in the height direction than the highest portion of the convex portion of the concavo-convex structure on the surface of the substrate, as described above. The thickness of the conductor is equal to or greater than the thickness of the convex portion. Further, the side surface of the conductor above the top of the convex portion of the concavo-convex structure on the surface of the base material is inclined with respect to the vertical direction of the base material surface, and the shape thereof is tapered and has a sharp shape resembling a triangle. It is preferable to do. The conductor having such a shape can be easily achieved by making the concave-convex structure on the surface of the base material into a sine wave shape in cross-sectional view and using an oblique vapor deposition method and isotropic etching described later. By producing a wire grid polarizer having such a shape of a conductor, even if the conductor is embedded with an adhesive resin, a decrease in the degree of polarization with respect to light having a wavelength of 600 nm or more is suppressed and less than 600 nm. Therefore, it is possible to suppress a decrease in the degree of polarization of light having a short wavelength, and to provide a versatile wire grid polarizer for optical sensors.

<Conductor formation method>
As a method for forming the conductor 21, in consideration of productivity, optical characteristics, and the like, a method of performing deposition (oblique deposition method) from a direction inclined with respect to the vertical direction of the base material 13 (uneven structure 22) is used. The oblique deposition method is a method in which metal is deposited and laminated so that metal particles are incident from a predetermined angle with respect to a direction perpendicular to the surface of the base material 13. The preferable range of the incident angle is determined from the convex portion of the concavo-convex structure 22 and the cross-sectional shape of the conductor 21 to be manufactured, and is generally preferably 5 ° to 45 °, more preferably 5 ° to 35 °. Furthermore, it is preferable to control the cross-sectional shape such as the height of the conductor 21 by gradually decreasing or increasing the incident angle while considering the projection effect of the metal laminated during the vapor deposition. In addition, when the base material 13 surface is curving, it is good also as performing vapor deposition from the direction inclined with respect to the normal line direction of the base material 13 surface.

  Specifically, a direction that is 5 ° or more and less than 45 ° with respect to the vertical direction at the center of the deposition area on the surface of the base material 13 having a concavo-convex structure extending on the surface in a specific direction at a predetermined pitch. The center of the vapor deposition source is provided to the conductor 21, and the conductor 21 is formed on the concavo-convex structure. More preferably, it is 5 ° or more and less than 35 ° with respect to the vertical direction at the center of the deposition region on the surface of the substrate 13 and 40 ° or more and 90 ° with respect to the extending direction of the concavo-convex structure 22 on the surface of the substrate 13. The center of the vapor deposition source is provided in the following angular direction. Thereby, the conductor 21 can be selectively provided on any one side surface of the convex portion of the concavo-convex structure 22 provided on the base material 13. When vapor deposition is performed while the substrate 13 is being conveyed, the vapor deposition may be performed so that the center of the deposition area and the center of the vapor deposition source at a certain moment satisfy the above-described conditions.

  Further, the conductor 21 can be formed by avoiding vapor deposition from the extending direction of the concavo-convex structure 22 of the light projecting polarization unit 11 and the light receiving polarization unit 12. In many optical sensors, the transmission axis direction of the light projecting polarization unit 11 and the transmission axis direction of the light receiving polarization unit 12 are substantially orthogonal to each other. Therefore, in consideration of the position conditions of the evaporation source described above, a wire grid polarizer is used. It is preferable that the extending direction of the concavo-convex structure 22 of one light projecting polarizing portion 11 and the extending direction of the concavo-convex structure 22 of the light receiving polarizing portion 12 intersect with the MD direction of the substrate 13 at approximately 45 degrees. . Thereby, since it becomes possible to place a vapor deposition source in MD direction of the base material 13, improvement in production efficiency is attained.

  When the above-described oblique vapor deposition method is used, the projecting portions of the concavo-convex structure 22 on the substrate surface and the extending direction of the conductor 21 are equal. Although the amount of metal vapor deposition for achieving the shape of the conductor 21 is determined by the shape of the convex portion of the concavo-convex structure 22, the average vapor deposition thickness is generally about 50 nm to 200 nm. The average thickness here refers to the thickness of the deposited material on the assumption that the material is deposited on the smooth glass substrate from the direction perpendicular to the glass surface, and is used as a measure of the metal deposition amount.

  Further, from the viewpoint of optical characteristics, it is preferable to remove the unnecessary conductor 21 by etching. The etching method is not particularly limited as long as it does not adversely affect the base material 13, the dielectric layer and the like constituting the concavo-convex structure 22 and can selectively remove the conductor 21 portion. From the viewpoint of controlling the shape of the body 21, a method of immersing in an alkaline aqueous solution is preferable.

<Dielectric material>
In the wire grid polarizer 1 shown in the present embodiment, in order to improve the adhesion between the material constituting the base material 13 and the conductor 21, a dielectric material having high adhesion between the two is preferably used. Can do. For example, a simple substance of silicon (Si) oxide such as silicon dioxide, nitride, halide, carbide or a composite thereof (dielectric obtained by mixing another element, simple substance or compound in a simple substance of dielectric), aluminum (Al ), Chromium (Cr), yttrium (Y), zirconia (Zr), tantalum (Ta), titanium (Ti), barium (Ba), indium (In), tin (Sn), zinc (Zn), magnesium (Mg) ), Calcium (Ca), cerium (Ce), copper (Cu) and other metal oxides, nitrides, halides, carbides alone or a composite thereof. The dielectric material only needs to be substantially transparent in the wavelength region where transmission polarization performance is to be obtained. There are no particular limitations on the method of laminating the dielectric material, and physical vapor deposition methods such as vacuum vapor deposition, sputtering, and ion plating can be suitably used.

<Board>
The wire grid polarizer 1 of the present invention can also use a substrate that holds a base material 13 having a concavo-convex structure 22. As the substrate, an inorganic material such as glass or a resin material can be used, but it is preferable to use a plate-like resin material that enables the production of the wire grid polarizer 1 by a roll process. The substrate is not an essential component in the wire grid polarizer 1. For example, the wire grid polarizer 1 can be configured using only the base material 13.

  Examples of the resin material include polymethyl methacrylate resin (PMMA), polycarbonate resin, polystyrene resin, cycloolefin resin (COP), cross-linked polyethylene resin, polyvinyl chloride resin, polyacrylate resin, polyphenylene ether resin, and modified polyphenylene ether resin. , Polyetherimide resin, polyether sulfone resin, polysulfone resin, polyether ketone resin, polyethylene terephthalate resin (PET), polyethylene naphthalate resin, polyethylene resin, polypropylene resin, polybutylene terephthalate resin, aromatic polyester resin, polyacetal resin , Polyamide resin, triacetyl cellulose resin (TAC), etc., UV curable resin such as acrylic, epoxy and urethane, and thermosetting Butter, and the like. Further, a UV curable resin or a thermosetting resin may be combined with an inorganic substrate such as glass, a thermoplastic resin, or the like, or these materials may be used alone.

  In order to avoid a decrease in the degree of polarization, it is preferable to reduce the in-plane retardation value of the substrate at a predetermined wavelength. For example, if the use of visible light is considered, the in-plane retardation value at a wavelength of 550 nm should be 30 nm or less. Is preferred. More preferably, it is 15 nm or less. Further, in order to prevent in-plane unevenness in the degree of polarization of polarized light given by the wire grid polarizer 1, it is necessary to manage phase difference values at two arbitrary points on the substrate surface. For example, use of visible light is considered. For example, the difference in the in-plane retardation value at a wavelength of 550 nm is preferably 10 nm or less, and more preferably the difference in retardation value is 5 nm or less. Examples of the substrate having such characteristics include TAC (triacetyl cellulose) resin, COP (cycloolefin polymer), PC (polycarbonate), PMMA (polymethyl methacrylate), and it is preferable to use these resin materials. .

<Adhesive resin>
In the wire grid polarizer 1 of the present invention, an adhesive resin is provided on the conductor 21 structure surface of the wire grid polarizer 1 due to the shape of the conductor 21, and the conductor 21 is embedded in the adhesive resin. Even so, the reduction width of the parallel transmittance and the degree of polarization can be reduced. For this reason, it is also possible to provide adhesive resin on the conductor structure surface of the wire grid polarizer 1. It is also possible to provide an adhesive resin on the opposite surface. By providing the adhesive resin, bonding with another optical member becomes possible. Moreover, when using the resin material (material used for the film for optical uses, etc.) for the board | substrate of the wire grid polarizer 1, the product reliability in a high temperature / humidity environment can be improved. Further, by providing an adhesive resin on the structure of the conductor 21 of the wire grid polarizer 1, the conductor 21 is embedded with an adhesive substance, and therefore the adhesive resin is used as a protective layer for preventing damage. It becomes possible.

  In general, the slow axis direction of a film for optical use in which the in-plane retardation value is controlled generally coincides with the MD direction or the TD direction of a film used as a substrate. For example, when the transmission axis direction of the light projection polarization unit 11 of the wire grid polarizer 1 and the transmission axis direction of the light reception polarization unit 12 are substantially orthogonal, the extending direction of the concavo-convex structure of the light projection polarization unit 11 It is preferable that the extending direction of the concavo-convex structure of the light receiving polarizing portion 12 intersects the MD direction of the substrate at approximately 45 degrees. However, with such a configuration, a film for optical use is used as the substrate, and a roll process is performed. The transmission axis direction of each polarization part of the wire grid polarizer manufactured in the above is oblique to the slow axis direction of the substrate and does not match. When a film for optical use is stored for a long time in a high-temperature and high-humidity environment, the orientation state of the film changes, and as a result, the in-plane retardation value may change. For example, in a film made of TAC resin, In some cases, the in-plane retardation value increases. In the wire grid polarizer 1 of the present invention, the slow axis direction of the substrate and the extending direction of the concavo-convex structure of the light projecting polarization unit 11 and the light receiving polarization unit 12, that is, the transmission axis direction are not substantially coincident. The polarization degree is likely to be affected by the increase in the in-plane retardation value. In order to reduce the change in the orientation state of the film and prevent the polarization degree of each polarization portion of the wire grid polarizer 1 from being lowered, the wire grid polarizer 1 using a film made of a TAC resin as a substrate is further fixed. For example, it is effective to adhere to a glass plate with an adhesive resin. Thereby, product reliability can be improved.

  As the adhesive resin, for example, a UV curable resin that is cured by UV irradiation or a pressure sensitive adhesive sheet in the form of a pressure sensitive adhesive can be used. In particular, when an adhesive resin is provided on the conductor structure surface and the conductor 21 is embedded, it is preferable to use a material containing as little acid as possible in the adhesive resin. By covering the conductor 21 of the wire grid polarizer 1 with a material containing as little acid as possible, the conductor 21 is prevented from being damaged without causing deterioration of the conductor 21 due to the acid contained in the adhesive resin. It is possible to suppress the decrease in the degree of polarization of each polarization unit described above. Further, when the adhesive resin is provided on the base material surface or the substrate surface, the polarization degree of each polarizing section described above does not occur without causing deterioration of the base material 13 or the substrate due to the acid contained in the adhesive resin. Reduction can be suppressed.

  In addition, by using an adhesive sheet, when stored for a long time in a high temperature and high humidity environment, the expansion and contraction of the substrate of the wire grid polarizer 1 can be relaxed, and the in-plane retardation value of the substrate or the like can be changed. Since it can suppress, it is preferable. As the pressure-sensitive adhesive sheet, it is preferable to use a sheet having an adhesive strength to glass of 1.5 N / 25 mm or more, preferably 5.0 N / 25 mm or more. For example, a pressure-sensitive adhesive sheet made of a resin such as an acrylic resin, a silicon resin, a urethane resin, a polyester resin, or an epoxy resin is preferable from the viewpoints of optical characteristics, adhesive strength, cost, and the like.

  The wire grid polarizer 1 can be used in the visible light, near-infrared light, and infrared light regions without impairing the optical characteristics. Therefore, the retroreflective photoelectric sensor and the biometric authentication device using the regions are used. It is preferably used in the application of the optical sensor. However, the present invention is not limited to the above embodiment, and various modifications can be made. In addition, the material, quantity, and the like in the above embodiment are examples, and can be changed as appropriate. In addition, the present invention can be appropriately modified and implemented without departing from the technical idea of the present invention.

<Light sensor>
In the optical sensor, a light projector is disposed so that the projection light emitted from the light projector is incident on the light projecting polarization section 11 of the wire grid polarizer 1 and is incident on the light receiving polarization section 12 of the wire grid polarizer 1. A light receiver is arranged so as to receive the transmitted measurement light. As the light projector, for example, an LED is used, and as the light receiver, for example, a photoresistor is used.

  As an optical sensor, for example, there is a regression reflection type photoelectric sensor 101 (see FIG. 5). In the retroreflective photoelectric sensor 101, the light projecting unit 102 and the light receiving unit 103 are adjacent to each other, and each polarizer is substantially on the same plane (in FIG. 5, one surface of the casing of the retroreflective photoelectric sensor 101). The transmission axis is substantially orthogonal. When the wire grid polarizer 1 is used for the retroreflective photoelectric sensor 101, the light projecting polarization unit 11 is disposed in the light projecting unit 102, and the light receiving polarization unit 12 is disposed in the light receiving unit 103.

  The retro-reflective photoelectric sensor 101 is used as an example of a usage method for detecting a product conveyance status in a production line. In this case, the retroreflection plate 104 that can change the polarization state by reflection is used. Further, the regressive reflection plate 104 is arranged so that the light from the light projecting unit 102 of the regressive reflection type photoelectric sensor 101 can be reflected and incident on the light receiving unit 103. When the polarized light emitted from the light projecting unit 102 is reflected by the return reflection plate 104, the polarization state of the reflected light with respect to the incident light changes, so that the reflected light can pass through the light receiving polarizer and the intensity of the light received by the light receiver. Becomes larger (see FIG. 6A). On the other hand, when the polarized light emitted from the light projecting unit 102 hits the object 105 passing between the sensor and the return reflection plate, the intensity of the light received by the light receiver is reduced (see FIG. 6B). For this reason, it is possible to detect the presence or absence of an object passing between the retroreflective photoelectric sensor 101 and the retroreflective plate 104 based on the intensity of the reflected light.

  As described above, by using the wire grid polarizer 1 of the present embodiment as shown in FIG. 1 for the optical sensor, the polarizers incorporated one by one at the time of manufacturing the polarizer optical sensor can be incorporated simultaneously at the same time. Therefore, it is possible to simplify the process and prevent erroneous incorporation. Moreover, since the wire grid polarizer 1 can make low the transmittance | permeability the boundary part 14 of the light projection polarization part 11 and the light reception polarization part 12, the separation property of a projection light and incident light becomes favorable, and a sensor's Detection accuracy can be improved and false detection can be prevented.

  In addition, since the light projecting polarizing section 11 and the light receiving polarizing section 12 having different transmission axis directions are provided on the surface of the same base material 13, processing such as bending the polarizer becomes unnecessary, and the optical characteristics of the polarizer can be ensured. It becomes easy. Thereby, it is possible to prevent the occurrence of the problem of false detection due to the light leakage of the polarizer.

  A light projector and a light receiver are arranged on the surface (back surface) opposite to the surface of the substrate on which the uneven structure of the light projecting polarization unit and the light receiving polarization unit and the conductor are provided. It is preferable to install. With this arrangement, the optical sensor can maintain excellent sensing accuracy even if the in-plane phase difference of the substrate of the wire grid polarizer changes.

(Embodiment 2)
In this embodiment, a wire grid polarizer having a mode different from that of the above embodiment will be described. Note that in this embodiment, only parts different from the above embodiment will be described, and common parts will be omitted. FIG. 9 and FIG. 10 are schematic diagrams showing configurations of the wire grid polarizer 2 and the wire grid polarizer 3 according to the present embodiment. FIG. 11 is a diagram illustrating a method for manufacturing the wire grid polarizer 2 according to the present embodiment.

  As shown in FIG. 9, the wire grid polarizer 2 according to the present embodiment includes a light projecting polarization unit 11 including a thin wire-like conductor extending in the horizontal direction (X direction), and a vertical direction (Y direction). And a light receiving polarization section 12 including a thin wire conductor extending. The outer shape of the light projecting polarizing section 11 is substantially square, and a light receiving polarizing section 12 having a substantially square outer shape is disposed near the center of the light projecting polarizing section 11. As shown in FIG. 10, the wire grid polarizer 3 according to the present embodiment includes a light projecting polarization unit 11 including a thin wire-like conductor extending in the horizontal direction (X direction), and the vertical direction (Y direction). ) And a light receiving polarization section 12 including a thin line-shaped conductor. The outer shape of the light projecting polarizing section 11 is substantially square, and a light receiving polarizing section 12 having a rhombus-shaped outer shape is disposed near the center of the light projecting polarizing section 11. Depending on the design, the wire grid polarizer 2 and the wire grid polarizer 3 may be fixed to a substrate or the like. The configurations of the light projecting polarization unit 11 and the light receiving polarization unit 12 are the same as those of the wire grid polarizer 1.

  Next, a method for manufacturing the wire grid polarizer 2 will be described. As shown in FIG. 11A, first, a wire grid polarizer including a polarizing unit 41 is manufactured. The wire grid polarizer provided with the polarizing portion 41 can be produced by forming a thin wire-like conductor extending in the extending direction of the concavo-convex structure on the surface of the base material constituting the concavo-convex structure. Next, as shown in FIG. 11B, a part P of the polarization unit 41 that will later become the light-receiving polarization unit 12 is cut out in a square shape. Thus, the light projecting polarizing section 11 having the square opening Q is formed. Here, a part P near the center of the polarizing part 41 is cut out, but the part to be cut out is not particularly limited as long as it is a part of the projecting polarizing part 11. Thereafter, as shown in FIG. 11C, the cut member (a part P of the polarizing portion 41) is rotated by 90 ° and fixed to the opening Q of the light projecting polarizing portion 11. Thus, the light projecting polarizing part 11 in which the conductor extends in a predetermined direction, and the light receiving polarizing part 12 that is configured by the cut member and extends at an angle of 90 ° with respect to the predetermined direction, The provided wire grid polarizer 2 is obtained. The relationship between the light projecting polarization unit 11 and the light receiving polarization unit 12 may be interchanged. That is, the cut member may function as the light projecting polarization unit 11. In addition, the cut-out original member may be rotated instead of the cut-out member (part P of the polarizing portion 41). The manufacturing method of the wire grid polarizer 3 is the same as the manufacturing method of the wire grid polarizer 2.

  As described above, when the light receiving polarization unit 12 is configured by using the members cut out from the light projecting polarization unit 11, the angle related to the rotation (see FIG. 11C) by performing the cutting (see FIG. 11B) with high accuracy. Therefore, it is possible to accurately control the polarization direction transmitted through the light projecting polarization unit 11 and the polarization direction transmitted through the light receiving polarization unit 12. That is, the polarization direction transmitted through the light projecting polarization unit 11 and the polarization direction transmitted through the light receiving polarization unit 12 can be accurately orthogonalized, and the contrast performance when used in an optical sensor can be improved. . Furthermore, since the member cut out after rotating is fixed to an opening area | region, dimension alignment etc. are easy.

  Here, a part P of the light projecting polarization unit 11 is cut out in a square shape, but the cut out shape is not limited thereto. In order to make the polarization direction transmitted through the light projecting polarization unit 11 and the polarization direction transmitted through the light receiving polarization unit 12 exactly orthogonal, at least the cut out shape may be four-fold symmetrical. In general, n-fold symmetry (n-fold rotational symmetry) means that when a certain shape is rotated around the center at an angle of 360 ° / n, it overlaps itself. That is, the four-fold symmetry means that when a certain shape is rotated around the center at an angle of 360 ° / 4 = 90 °, it overlaps itself.

  Further, the polarization direction transmitted through the light projecting polarization unit 11 and the polarization direction transmitted through the light receiving polarization unit 12 may be controlled by other than orthogonal (90 °). The angle formed between the polarization direction transmitted through the light projecting polarization unit 11 and the polarization direction transmitted through the light receiving polarization unit 12 can be controlled by the rotation angle of the cut member. Here, when the rotation angle is 360 ° / n (n is a positive integer), the cut shape may be n-fold symmetric. Examples of the n-fold symmetrical shape include a regular n-gon. By controlling the shape to be cut out in this way, the rotation angle can be accurately controlled. Therefore, the angle formed between the polarization direction transmitted through the light projecting polarization unit 11 and the polarization direction transmitted through the light reception polarization unit 12 can be accurately determined. Can be controlled.

  Further, a plurality of regions to be cut out may be provided. Furthermore, the rotation angles of the plurality of members cut out may be varied depending on the application. For example, it is possible to cut out a three-fold symmetrical shape in one region and rotate it 120 °, and cut out another region in a five-fold symmetrical shape and rotate it 72 °.

  In addition, the manufacturing method shown in the present embodiment is used for manufacturing a transmissive wire grid polarizer as described above, as well as a resin-laminated polarizing plate, which is a general reflective polarizing plate, and a glass substrate. It can also be used when controlling the polarization direction in the wire grid polarizer used. Also in these cases, accurate control of the polarization direction can be realized.

  As described above, since the wire grid polarizer 2 and the wire grid polarizer 3 according to the present embodiment can be manufactured using a single wire grid polarizer, it is necessary to use a special template to realize the polarization direction. There is no. Thereby, manufacturing cost can be suppressed. Note that the structure of this embodiment can be combined as appropriate with any of the other embodiments.

Example 1
In this example, in the wire grid polarizer shown in FIG. 1 and the like, optical characteristics and the like were confirmed when the concavo-convex structure was sinusoidal. The present invention is described in detail below, but the present invention is not limited to the configuration of the examples.

<Preparation of transfer film using UV curable resin>
First, a transfer film having a region in which the extending direction of the concavo-convex structure is used for a wire grid polarizer is produced. A Ni mold was used for the production of a transfer film having regions with different concavo-convex structure extending directions. In a cross-sectional view, a plurality of resin plates having a roughly sinusoidal uneven structure are joined to produce a resin plate (mold) having regions in which the extending directions of the uneven structure are orthogonal to each other on the same plate, A Ni mold was produced from the plate (mold) by electrolytic plating. The Ni mold is referred to as mold A (FIG. 4 and the like).

  As the substrate, a TAC film (TD80UL-H: manufactured by Fuji Photo Film Co., Ltd.) made of a triacetyl cellulose resin having a thickness of 80 μm was used. The in-plane retardation value of the TAC film at a wavelength of 550 nm was 3.3 nm, and the slow axis substantially coincided with the MD direction. In addition, KOBRA-WR manufactured by Oji Scientific Instruments, which is a polarization analyzer using a parallel Nicol method, was used as a measuring device for in-plane retardation values. The phase difference value when the wavelength of the measurement light was 550 nm and the incident angle was 0 degree was defined as the in-plane retardation value.

Acrylic UV curable resin (refractive index of 1.52) is applied to the above-mentioned TAC film by about 3 μm, and the angle formed by the extending direction of the uneven structure of the mold A and the MD direction of the TAC film is 45 degrees. The mold A was superimposed on the TAC film. A UV lamp having a center wavelength of 365 nm was operated, and UV irradiation of 1000 mJ / cm ² was performed from the TAC film side to transfer the uneven structure of the mold A onto the UV curable resin. Thereafter, the TAC film was peeled from the mold to obtain a transfer film A in which a concavo-convex structure having a length of 300 mm and a width of 200 mm was transferred to the substrate surface made of a UV curable resin. In the transfer film A, the angle formed by the extending direction of the concavo-convex structure and the MD direction of the TAC film was 45 degrees. When the cross-sectional view of the transfer film A was confirmed, the pitch width of the concavo-convex structure was 145 nm, and it was substantially sinusoidal.

<Formation of dielectric layer using sputtering method>
Next, silicon dioxide was deposited as a dielectric layer on the surface of the transfer film A having a concavo-convex structure by sputtering. The conditions of the sputtering apparatus were an Ar gas pressure of 0.2 Pa, a sputtering power of 770 W / cm ² , and a coating speed of 0.1 nm / s. Under these conditions, the dielectric layer was formed so that the thickness of the dielectric layer on the transfer film A was 3 nm in terms of a flat film.

<Formation of conductor using oblique deposition method>
Next, an aluminum (Al) film was formed on the surface of the base material having a concavo-convex structure of the transfer film A on which the dielectric layer was formed by vacuum deposition. The film formation conditions for the aluminum film were as follows: the temperature was normal temperature, the degree of vacuum was 2.0 × 10 ⁻³ Pa, and the deposition rate was 40 nm / s. In order to measure the thickness of the aluminum film, a glass substrate having a smooth surface was inserted into the apparatus simultaneously with the transfer film A, and the thickness of the aluminum film on the smooth glass substrate was defined as the average thickness of the aluminum film. In a plane perpendicular to the film width direction (TD direction) of the substrate, the transfer film A is adjusted so that the vapor deposition source exists in an angle direction of 30 degrees with respect to the vertical direction of the substrate. The transfer film A is adjusted so that the evaporation source exists in a plane that is at an angle of 45 degrees with the extending direction of the concavo-convex structure of the transfer film A so that the average thickness of the aluminum film becomes 120 nm. , Al was vapor-deposited. The average thickness here refers to the thickness of the deposited material on the assumption that the material is deposited on the smooth glass substrate from the direction perpendicular to the glass surface, and is used as a measure of the deposition amount.

<Removal of unnecessary aluminum film>
Next, for the purpose of removing an unnecessary aluminum film, the transfer film A on which the aluminum film was deposited was immersed in a 0.1 wt% aqueous sodium hydroxide solution at room temperature for 70 seconds. Immediately after that, the film was washed with water and dried.

<Evaluation of optical properties>
The parallel transmittance and orthogonal transmittance of an arbitrary polarizing part of the wire grid polarizer A produced based on the transfer film A were measured, and the degree of polarization was calculated. The parallel transmittance and the orthogonal transmittance were measured using VAP-7070 manufactured by JASCO Corporation. The measuring device is provided with a measuring polarizer in the vicinity of the light source, and when measuring the parallel transmittance and the orthogonal transmittance of the wire grid polarizer A, it is opposite to the conductor structure surface on the substrate of the wire grid polarizer A. It arrange | positioned so that it may enter from the surface (substrate surface) of this.

The degree of polarization P ′ (λ) at a wavelength λ is expressed by the following equation, where Imin is the transmittance of light having a wavelength λ that oscillates parallel to the conductor, and Imax is transmittance of light having a wavelength λ that oscillates in the orthogonal direction. I asked for it.
P ′ (λ) = [(Imax−Imin) / (Imax + Imin)] × 100%

  Table 1 shows the single transmittance (visibility correction value) calculated from the transmittance measuring method and the degree of polarization at a wavelength of 550 nm.

  The extending direction of the conductor of the wire grid polarizer A has an angle of 45 degrees with respect to the MD direction of the substrate, and the variation in the extending direction of the conductor in the same polarizing portion is ± 0. It was within 6 degrees. In the wire grid polarizer A, the conductor is unevenly distributed on one side surface of the convex portion of the concavo-convex structure on the substrate in a cross-sectional view of an arbitrary polarizing portion. In addition, a part of the conductor exists above the top of the convex portion of the concavo-convex structure, and the side surface above the top of the convex portion of the conductor is inclined with respect to the vertical direction, and its shape resembles a triangle. The shape was sharp. The thickness of the conductor on the side surface of the convex portion in the direction parallel to the base material was 30 nm or more. Moreover, the convex part axis | shaft which followed the top part of the convex part of the uneven structure on a base material and followed the standing direction of a convex part, and the conductor axis | shaft which followed the top part of a conductor and followed the standing direction differed.

(Example 2)
In this example, in the wire grid polarizer shown in FIG. 1 and the like, optical characteristics and the like were confirmed when the concavo-convex structure was rectangular. The present invention is described in detail below, but the present invention is not limited to the configuration of the examples.

<Preparation of transfer film using UV curable resin>
First, a transfer film having a region in which the extending direction of the concavo-convex structure is used for a wire grid polarizer is produced. A Ni mold was used for the production of a transfer film having regions with different concavo-convex structure extending directions. In cross-sectional view, a plurality of resin plates having a substantially rectangular uneven structure are joined to produce a resin plate (mold) having regions in which the extending directions of the uneven structure are orthogonal to each other on the same plate, A Ni mold was produced from the resin plate (mold) by electrolytic plating. The Ni mold is referred to as mold B. The only difference from the mold A in Example 1 is that the uneven structure is substantially rectangular.

  In the same process as in Example 1, a transfer film B having a concavo-convex structure transferred onto a substrate surface made of a UV curable resin was obtained. The transfer film B was produced in the same process as in Example 1 except that the mold B was used instead of the mold A. When the cross-sectional view of the transfer film B was confirmed, the pitch width of the concavo-convex structure was 145 nm, and was substantially rectangular.

<Formation of dielectric layer using sputtering method>
Thereafter, silicon dioxide was formed as a dielectric layer on the surface of the base material having a concavo-convex structure of the transfer film B by a sputtering method in the same manner as in Example 1.

<Formation of conductor using oblique deposition method>
Next, an aluminum (Al) film was formed by vacuum deposition on the surface of the base material having a concavo-convex structure of the transfer film B on which the dielectric layer was formed. Details of the process are the same as in Example 1.

<Removal of unnecessary aluminum film>
Next, for the purpose of removing an unnecessary aluminum film, the transfer film B on which the aluminum film was deposited was immersed in a 0.1 wt% aqueous sodium hydroxide solution at room temperature for 70 seconds. Immediately after that, the film was washed with water and dried.

<Evaluation of optical properties>
The parallel transmittance and orthogonal transmittance of an arbitrary polarization part of the wire grid polarizer B produced based on the transfer film B were measured, and the degree of polarization was calculated. The details of the measurement are the same as in Example 1.

  Table 1 shows the single transmittance (visibility correction value) calculated from the transmittance measuring method and the degree of polarization at a wavelength of 550 nm.

  The extending direction of the conductor of the wire grid polarizer B has an angle of 45 degrees with respect to the MD direction of the substrate, and the variation in the extending direction of the conductor in the same polarizing portion is ± 0. It was within 7 degrees. In the wire grid polarizer B, the conductor is unevenly distributed on one side surface of the convex portion of the concavo-convex structure on the substrate in a cross-sectional view of an arbitrary polarizing portion. In addition, although a part of the conductor exists above the top of the convex portion of the concavo-convex structure, the side surface above the top of the convex portion is substantially parallel to the vertical direction, and the shape thereof is substantially rectangular or It was roughly trapezoidal. Moreover, the convex part axis | shaft which followed the top part of the convex part of the uneven structure on a base material and followed the standing direction of a convex part, and the conductor axis | shaft which followed the top part of a conductor and followed the standing direction differed.

(Example 3)
In this example, the optical characteristics and the like when the conductor of the wire grid polarizer was embedded with an adhesive resin were confirmed. The present invention is described in detail below, but the present invention is not limited to the configuration of the examples.

  First, one release film of the acrylic pressure-sensitive adhesive sheet having release films on both surfaces was peeled, and the acrylic pressure-sensitive adhesive sheet was bonded to the conductor structure surface on the substrate of the wire grid polarizer A. Then, after peeling the peeling film of the adhesive sheet of the wire grid polarizer A in which the conductor was embedded, and bonding it to a flat glass plate (Tempax, thickness 1.1 mm), it was stored at room temperature for 24 hours. . This is designated as bonded body 1. Moreover, the bonding body 2 using the wire grid polarizer B was produced similarly.

<Measurement of adhesive strength>
In the bonded body 1, the adhesive strength with the glass of an acrylic adhesive sheet was measured. The adhesive strength of the pressure-sensitive adhesive sheet was measured according to JIS-Z-0237 except that the test plate was changed from a SUS steel plate to a glass plate. A pressure-sensitive adhesive sheet having a release film on both sides was cut into a width of 25 mm, and a test piece prepared by bonding one surface of the pressure-sensitive adhesive sheet to a PET film was bonded to a glass plate as a test plate. It was bonded to a test plate and allowed to stand at room temperature for 20 minutes, and then the adhesive force between the glass and the pressure-sensitive adhesive was measured using a tensile tester (a condition of a peeling speed of 300 mm / min and a peeling angle of 180 °). Thus, the adhesive strength with the glass of the acrylic adhesive sheet measured was 8.6 N / 25mm.

<Evaluation of optical properties>
The parallel transmittance | permeability and orthogonal transmittance | permeability of the arbitrary polarizing parts of the bonding body 1 and the bonding body 2 were measured, and the polarization degree was calculated. Table 1 shows the single transmittance (visibility correction value) calculated from the transmittance measuring method and the degree of polarization at a wavelength of 550 nm.

  The bonding body 1 and the bonding body 2 are obtained by bonding an acrylic pressure-sensitive adhesive sheet to the conductor structure surface on the substrate of the wire grid polarizer A and the wire grid polarizer B, and embedding the conductor. The change in the single transmittance with corrected visibility and the degree of polarization at a wavelength of 550 nm before and after bonding of the adhesive sheet are smaller in the wire grid polarizer A than in the wire grid polarizer B, and the transmittance and polarization degree The decrease was small. This is because, in a cross-sectional view, the concavo-convex structure of the substrate of the wire grid polarizer A is approximately sinusoidal, the conductor shape above the top of the convex part of the concavo-convex structure is a sharp shape, and is on the side of the convex part This is because the thickness of the conductor in the direction parallel to the base material is sufficiently thick at 30 nm or more.

Example 4
In the present Example, the optical characteristic etc. when a wire grid polarizer was bonded to a fixing material were confirmed. The present invention is described in detail below, but the present invention is not limited to the configuration of the examples.

  First, peel off one release film of an acrylic adhesive sheet that has release films on both sides, and paste the acrylic adhesive sheet on the opposite side (substrate surface) of the conductor structure surface on the substrate of the wire grid polarizer did. Then, after peeling the peeling film of the adhesive sheet of the said wire grid polarizer A provided with the said adhesive sheet on the board | substrate surface and bonding to a flat glass plate (Tempax, thickness 1.1mm), it is 24 at room temperature. Stored for hours. This is designated as bonded body 3. The acrylic pressure-sensitive adhesive sheet was the same as in Example 3.

  The wire grid polarizer A and the bonded body 3 were placed in a constant temperature and humidity chamber (model: μ-2002, manufactured by Isuzu Seisakusho) with a temperature of 85 degrees and a relative humidity of 85%, and a constant temperature and humidity test was performed for 600 hours. In Table 2, the change of the polarization degree of the arbitrary polarization | polarized-light part of the wire grid polarizer A and the bonding body 3 is shown.

When the constant temperature and humidity test was performed for 600 hours under the above-described conditions, the wire grid polarizer A had a decrease in the degree of polarization as described above, but the bonding body 3 in which the substrate surface was bonded to the glass plate was changed. Was not seen. Moreover, when the external appearance of the wire grid polarizer A was observed, the abnormal appearance (curling and wrinkle generation of the wire grid polarizer A) that was not observed before the constant temperature and humidity test was confirmed. Appearance change was not seen. This is because the film made of TAC resin used for the substrate of the wire grid polarizer A changed the orientation state of the film and changed the in-plane retardation due to long-term storage in a high temperature and high humidity environment. The bonding body 3 is obtained by bonding a wire grid polarizer having a film made of a TAC resin as a substrate to a fixing material with an adhesive sheet, and the change in the orientation state of the film by long-term storage in a high temperature and high humidity environment. Therefore, it was possible to prevent a decrease in the degree of polarization of an arbitrary polarizing portion of the bonded body 3.

  From the above examples, it can be seen that a wire grid polarizer with a concavo-convex structure having a sinusoidal structure can obtain a higher degree of polarization than a wire grid polarizer with a concavo-convex structure having a rectangular shape. In addition, an adhesive sheet is bonded to the conductor structure surface on the substrate of a wire grid polarizer having a sine wave-like concavo-convex structure. It turns out that the fall of the transmittance | permeability and a polarization degree can be made small compared with the bonded body which bonded the acrylic adhesive sheet to the conductor structure surface on the base material of a child, and embedded the conductor. It can also be seen that by bonding the wire grid polarizer to the fixing material, the change in the orientation state of the film due to long-term storage in a high-temperature and high-humidity environment can be reduced, and a decrease in the degree of polarization can be prevented. In addition, it can be seen that optical sensors manufactured using these have little change in product performance over a long period of time.

  The wire grid polarizer of the present invention can be used, for example, in an optical sensor that uses two different polarizations.

1, 2, 3 Wire grid polarizer 11 Light-projecting polarizing section 12 Light-receiving polarizing section 13 Base material 21 Conductor 22 Concavity and convexity 101 Regression reflection type photoelectric sensor 102 Light-projecting section 103 Light-receiving section

Claims (17)

  A projector disposed to emit projection light that enters the light projecting polarization section of the wire grid polarizer, and a measurement light transmitted through the light receiving polarization section of the wire grid polarizer. A light grid polarizer used for an optical sensor, wherein the light projecting polarization unit and the light receiving polarization unit having different transmission axis directions are formed on the same substrate surface. A wire grid polarizer characterized by comprising:   The light projecting polarizing section includes a first concavo-convex structure portion in which a concavo-convex structure extends in a first direction at a predetermined interval in a cross section perpendicular to a direction in which the concavo-convex structure extends, and the first concavo-convex structure. A first conductor provided so as to be unevenly distributed on one side surface of the convex portion of the first portion, and the light-receiving polarizing portion has a concavo-convex structure different from the first direction at a predetermined interval. 2. A second concavo-convex structure portion extending in the direction of the second undulation portion, and a second conductor provided so as to be unevenly distributed on one side surface of the second concavo-convex structure portion. The wire grid polarizer as described in.   The wire grid polarizer according to claim 2, wherein the concavo-convex structure is constituted by a base material made of a resin.   In the cross section perpendicular to the direction in which the concavo-convex structure extends, the concavo-convex structure has a substantially sinusoidal shape, and passes through the top of the convex portion of the concavo-convex structure with respect to the convex axis along the standing direction of the convex portion. 4. The wire grid polarizer according to claim 2, wherein a conductor axis passing through a top portion of the conductor and along a standing direction of the conductor is varied. 5.   A boundary portion between the light projecting polarizing portion and the light receiving polarizing portion on the surface of the base material is a region having no concavo-convex structure continuous with the concavo-convex structure forming the light projecting polarizing portion or the light receiving polarizing portion. The wire grid polarizer according to any one of claims 2 to 4, wherein the wire grid polarizer is provided.   6. The concavo-convex structure is formed in the same process using a metal stamper manufactured from a mold having a region where the concavo-convex structure is provided on the same surface. Item 2. A wire grid polarizer according to item 1.   The wire grid polarizer according to claim 6, wherein the mold is manufactured by bonding a plurality of plates having a concavo-convex structure on a surface thereof.   The said casting_mold | template is produced by bonding the some plate after bonding the uneven | corrugated structure surface of the some plate which has an uneven structure on the surface to a low-adhesion adhesive sheet. Wire grid polarizer.   In the light projecting polarization unit or the light receiving polarization unit, variation in the extending direction of the first conductor or variation in the extending direction of the second conductor is within ± 3 degrees. The wire grid polarizer according to any one of claims 2 to 8, wherein the wire grid polarizer is characterized.   10. The wire grid polarizer according to claim 2, wherein the first conductor and the second conductor are embedded with an adhesive resin. 11.   The wire grid polarizer according to any one of claims 1 to 10, wherein a boundary portion between the light projecting polarization unit and the light receiving polarization unit has a low transmittance.   The wire grid polarizer according to any one of claims 1 to 11, wherein the base member includes a substrate.   The extending direction of the polarization axis of the light projecting polarization unit and the extending direction of the polarization axis of the light receiving polarization unit are orthogonal to each other. The wire grid polarizer according to claim 12, wherein an extending direction of a polarization axis of the polarizing section for use intersects with an MD direction of the substrate at 45 degrees. A projector disposed to emit projection light that enters the light projecting polarization section of the wire grid polarizer, and a measurement light transmitted through the light receiving polarization section of the wire grid polarizer. A wire grid polarizer used for an optical sensor comprising:
A part of a polarizing part having a conductor extending in a predetermined direction is cut into a predetermined shape, and separated into a cut-out member and a cut-out original member having an opening corresponding to the cut-out member, The cut member or the cutting source member is rotated so that the extending direction of the conductor of the cut member and the extending direction of the conductor of the cutting member form a predetermined angle. A wire grid polarizer comprising: the light projecting polarization unit and the light receiving polarization unit formed by fixing the cut member to the opening of the cut member.   15. The wire grid polarization according to claim 14, wherein the cut-out member has a n-fold symmetry shape, and the rotation angle of the cut-out member or the cut-out member is 360 ° / n. Child.   The optical sensor using the wire grid polarizer of any one of Claims 1-15. A light projector and a light receiver are provided on the opposite side of the substrate surface of the wire grid polarizer in which the uneven structure of the light projecting polarization unit and the light receiving polarization unit and a conductor are provided on the substrate surface. The optical sensor according to claim 16, wherein the optical sensor is disposed.

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