JP2007041243A - Polarizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizer capable of improving adhesion strength of a conductor with a dielectric material or a substrate, thereby realizing stabilization polarizing characteristics and improvement of reliability. <P>SOLUTION: The polarizer comprises a light-transmitting substrate and a polarizing film having a stripe structure formed by collaterally arranging a conductor and a light-transmitting dielectric material on the surface of the substrate, with a plurality of interfaces between the conductor and the dielectric material formed in a non-parallel state. In another embodiment, the polarizer is structured by forming at least a part of the interface into a loosely curved plane in a nonlinear state so as to extend the length of each interface, to sufficiently keep the interfacial area as a contact area between the conductor and the dielectric material and to improve adhesiveness between the conductor and the dielectric material. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polarizer.

  Conventionally, there has been devised a polarizer comprising a polarizing film formed by alternately combining a conductor and a dielectric on a surface of an optically transparent substrate material (for example, a patent). Reference 1).

Japanese Patent Laid-Open No. 2002-328222 (page 5-7, FIG. 1-3)

  A polarizer 100 shown in FIG. 19 has a dielectric 102 disposed on the surface of an optically transparent substrate 101, and a plurality of thin-film conductors having a width W and a height H while being held by the dielectric 102. This is a polarizer configured by standing 103 on the surface of the substrate 101 in parallel with each other at a predetermined distance d.

  A plurality of linear grooves are formed in parallel on the surface of the dielectric 102 by a method such as exposure-dry etching on the top of the substrate 101, so that the dielectric 102 such as silicon dioxide is several μm on the surface of the substrate 101. The thickness is formed. Further, by burying the conductor 103 in the groove portion, the adjacent conductors 103 are bonded and erected on the dielectric 102 with a distance d.

  The operation of the polarizer 100 will be described with reference to FIG. As shown in FIG. 20, when light from the outside is incident on the polarizer 100, a polarization component 104 (TE polarized light) whose wavefront is parallel to the side surface of the conductor 103 and whose electric field E is parallel to the y direction in the figure is Reflected or absorbed. On the other hand, the polarization component 105 (TM polarization) whose wavefront is perpendicular to the side surface of the conductor 103 and whose electric field E is parallel to the x direction in the drawing is transmitted through the polarizer 100. Note that the symbol H of the polarization component 104 represents a magnetic field.

  In the TE polarized light 104, the length (height H) of the conductor 103 is long enough to substantially act as a conductor as compared with the wavelength, so that a transient current flows through the conductor 103. As a result, since the reflection and absorption performance similar to the phenomenon on the metal surface is obtained, the TE polarized light 104 does not pass through the polarizer 100.

  On the other hand, in the TM polarized light 105, since the length (width W) of the conductor 103 is shorter than the wavelength, it does not substantially act as a conductor, and no transient current flows through the conductor 103. Therefore, the TM polarized light 105 is transmitted through the polarizer 100.

  Since the conductor 103 is fixed in contact with the substrate 101 or the dielectric 102, it does not peel off from the substrate 101 and maintains good adhesion at the interface with the substrate 101 or with the dielectric 102. I can do it. Therefore, the polarizer 100 can realize a stable polarization characteristic, and can be an optical element that is not easily destroyed by various external forces received in processes such as machining and assembly. It is explained.

  However, in the conventional polarizer 100, as shown in FIG. 21, the boundary surfaces 106 between the conductor 103 and the dielectric 102 are parallel to each other when viewed from the plane direction (z direction in FIG. 20). Is formed. Therefore, in the actually manufactured polarizer 100, it is not possible to secure a sufficient area of the boundary surface 106, which is a contact portion between the conductor 103 and the dielectric 102, and the conductor 103 and the dielectric 102 The adhesion strength could not be raised to a sufficient level. Therefore, due to insufficient adhesion strength, the polarization characteristics of the entire polarizer become unstable, and the polarizer breaks during various processes such as processing and assembly, resulting in a decrease in reliability.

  The present invention has been made in view of the above-described problems. By improving the adhesion strength between a conductor and a dielectric or a substrate, polarization having stabilized polarization characteristics and improved reliability. The purpose is to provide children.

The invention according to claim 1 of the present invention is a polarizer comprising a light transmissive substrate and a stripe-shaped polarizing film composed of a conductor and a light transmissive dielectric on the substrate surface.
The polarizer is characterized in that a plurality of boundary surfaces between the conductor and the dielectric are formed in a non-parallel state.

According to a second aspect of the present invention, there is provided a polarizing portion having a stripe structure by embedding a light-transmitting substrate and a plurality of grooves engraved on the substrate surface and embedding a conductor in the grooves. In the polarizer,
The polarizer is characterized in that a plurality of boundary surfaces between the conductor and the groove are formed in a non-parallel state.

  Furthermore, the invention described in claim 3 is characterized in that the conductor is embedded in a second groove formed by a dielectric uniformly provided on the surface of the groove. A child.

According to a fourth aspect of the present invention, there is provided a polarizing part comprising a light-transmitting substrate and a plurality of grooves formed on the substrate surface, and a conductor is formed on a side surface of the groove. In a polarizer comprising:
The polarizer is characterized in that a plurality of boundary surfaces between the conductor and the groove are formed in a non-parallel state.

  Furthermore, the invention described in claim 5 is the polarizer according to any one of claims 1 to 4, wherein the conductor is replaced with a semiconductor.

  The invention according to claim 6 is the polarizer according to claim 1 or 3, wherein one of the conductor and the dielectric is replaced with a semiconductor.

  Furthermore, the invention described in claim 7 is the polarizer according to any one of claims 1 to 6, wherein at least a part of the boundary surface is formed in a non-linear state.

  According to the polarizer according to claim 1 and claim 3 of the present invention, compared with a conventional polarizer configured such that each boundary surface between the conductor and the dielectric is in a straight line state and parallel to each other, The length of each boundary surface can be extended by the amount of non-parallel state. Therefore, it is possible to sufficiently secure the area of the boundary surface that is a contact portion between the conductor and the dielectric, and it is possible to improve the adhesion between the conductor and the dielectric.

  Along with improved adhesion, it can stabilize the polarization characteristics of the polarizer and prevent the polarizer from being broken during machining and assembly processes. Reliability improvement is also achieved.

  Furthermore, by forming the polarizer with the boundary surface in a non-parallel state, the manufacturing tolerance can be set moderately, and the manufacturing of the polarizer can be facilitated and the cost can be reduced.

  Moreover, according to the polarizer of Claim 2 and Claim 4 of this invention, the length of each boundary surface can be extended by making each boundary surface of a conductor and a board | substrate groove part non-parallel. I can do it. Therefore, the area of the boundary surface that is the contact portion between the conductor and the groove can be sufficiently secured, and the adhesion between the conductor and the substrate can be improved.

  Along with improved adhesion, it can stabilize the polarization characteristics of the polarizer and prevent the polarizer from being broken during machining and assembly processes. Reliability improvement is also achieved.

  Furthermore, by forming the polarizer with the boundary surface in a non-parallel state, the manufacturing tolerance can be set moderately, and the manufacturing of the polarizer can be facilitated and the cost can be reduced.

  Furthermore, according to the polarizer of the fourth aspect, by setting at least a part of the shape of the boundary surface in a non-linear state, the area of the boundary surface can be further expanded compared to the linear shape. For this reason, it is possible to further improve the adhesion between the conductor and the dielectric or between the conductor and the substrate.

  Moreover, according to the polarizer of Claim 5 or 6, it becomes possible to produce a polarizer other than a conductor material or a dielectric material.

<First Embodiment>
Hereinafter, a polarizer 1 according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view schematically showing a polarizer according to a first embodiment of the present invention, FIG. 2 is a plan view of the polarizer of FIG. 1, and FIG. 3 is a diagram showing conductors in the polarizer of FIG. FIG. 4 is a partially enlarged plan view in which a part of a boundary surface with a dielectric is enlarged, and FIG. 4 is a front view showing a polarization operation of the polarizer of FIG. 5 to 9 are explanatory views showing the manufacturing process of the polarizer 1. The x-axis to z-axis shown in FIGS. 1 to 9 correspond to each other.

  The polarizer 1 has a substrate 2 made of an optically transparent light-transmitting material, and dielectrics 3 are arranged on the surface of the substrate 2 at a predetermined interval, and are held between the dielectrics 3. On the other hand, a plurality of thin-film conductors 4 having a width W and a height H are formed by standing on the surface of the substrate 2 with a predetermined distance d. A plurality of dielectrics 3, 3... And conductors 4, 4... Are alternately arranged to form a polarizing film 8 having a stripe structure, and this polarizing film 8 is provided on the surface of the substrate 2. .

  The substrate 2 only needs to be optically transparent with respect to the wavelength of incident light. For example, a glass substrate, a resin substrate such as acrylic or polycarbonate, a single crystal substrate, or the like can be used. Depending on the application of the polarizer 1, for example, soda lime glass, aluminosilicate glass, borosilicate glass, quartz glass, silicon crystal, BK-7 glass (BK is manufactured by Hoya Glass Co., Ltd.) (Trademark Name), lead glass, germanium crystal, lithium niobate crystal, and the like can be selected. Among these, quartz glass has a high transmittance of light in a wavelength band from ultraviolet to near infrared, and is particularly suitable when the polarizer 1 is used in a wavelength band for optical communication (1.31 μm to 1.55 μm). Quartz glass is also easy to apply to surface micromachining techniques such as laser ablation and dry etching. When the polarizer 1 is applied to optical communication, a gallium-arsenide single crystal substrate may be used for the substrate 2 in addition to quartz glass.

  When a material other than quartz glass is used for the substrate 2, a light transmitting material (eg, silicon dioxide film (quartz), silicon, plastic, etc.) is formed on the surface of the substrate 2 to a thickness of several μm. May be used. In this case, the polarizer 1 may realize the polarization characteristics at a portion of several μm from the surface of the substrate 2.

As the dielectric 3 for fixing and holding the conductor 4, a material having a refractive index equal to or substantially equal to the refractive index of the substrate 2 is preferable in terms of compensating the phase of the polarized light component transmitted through the polarizer 1. Such a material is desirably the same as the substrate 2, but when a material different from the substrate 2 is used, it is preferable to select a material having a refractive index similar to that of the substrate 2. As a specific material, any optically transparent light transmittance may be used, and Si, Al, Be, Cs, Rb, K, Na, Li, Ba, Sr, Ca, Mg, Zn, Cd, Pb, Bi, Ge, Ta, Tl, Ti, P, Ag, As, Sb, Te, Y, Sc, Sn, Hf, W, Nb, Cr, Mn, B, Zr, Zn, and other oxides (eg, SiO ₂ , TiO ₂ , Al ₂ O ₃ , Ta ₂ O ₅ , ZrO _2, MgO, SnO ₂ , ZnO, etc.), a glass containing at least one or a semiconductor such as Si, Si ₃ N ₄ , SiO _x N Any compound such as _y and MgF ₂ may be used. The dielectric 3 may be replaced with another transparent solid, for example, a curable transparent resin such as a UV adhesive.

  On the other hand, the material of the conductor 4 includes Au, Ag, Cu, Pd, Pt, Al, Ge, Rh, Si, Ni, Co, Mn, Fe, Cr, Ti, Ru, Nb, Nd, Yb, Y, It is preferably at least one selected from the group consisting of Mo, In, Bi, Ta, W, Be, and Mg. Since these have a relatively large electric conductivity and relative dielectric constant, when used as the conductor 4, the reflection and absorption characteristics of the polarizer 1 with respect to the incident light are increased, so that the polarization characteristics of the polarizer 1 are improved. I can do it. In particular, Au, Ag, Al, Cr, Co, W, Fe, Cu, Be, Mg, and Rh are desirable because of their low electric resistance.

  As the distance d is set smaller, the polarization separation effect becomes larger. However, when d is less than 0.1λ (λ: wavelength of incident light), the reflection and absorption of TM polarized light to be transmitted increases, and the incident light is inserted. Since the loss increases, the performance of the polarizing element 1 decreases. On the other hand, if it exceeds 0.5λ, the conductor 4 that contributes to reflect and absorb TE polarized light with respect to the used wavelength λ does not exist sufficiently. As a result, the transmittance of TE polarized light becomes high, and the polarizer 1 does not function. In addition, it is necessary to consider that a diffraction phenomenon occurs unless the wavelength λ is less than half. The distance d is preferably set in consideration of the above points.

  The height H of the conductor 4 is long enough to substantially act as a conductor with respect to the traveling direction of incident light, and a transient current flows upon receiving the TE-polarized light. As a result, the reflection is similar to the phenomenon on the metal surface. In addition, it is desirable to set the dimensions so that the absorption performance is obtained and the TE polarized light is not transmitted.

  As the width W of the conductor 4 decreases with respect to the distance d, the insertion loss of the polarizer 1 decreases. However, if the width W is set too small, a sufficient extinction ratio cannot be obtained. Further, the extinction ratio of the polarizer 1 increases as the width W increases with respect to the distance d. However, if the width W is set too large, the reflection and absorption of TM polarized light to be transmitted increases, and the insertion loss of incident light increases. This is not preferable. From the above points, it is preferable to set the width W.

  A circle A in FIG. 2 is a part of a plurality of boundary surfaces 5 between each conductor 4 and each dielectric 3, and an enlarged view of the circle A is shown in FIG. 3 (a) or (b). . As shown in FIG. 3, when each boundary surface 5 between the conductor 4 and the dielectric 3 of the polarizer 1 is enlarged and observed, the boundary surfaces 5 are not parallel to each other, and are not parallel to each other. As shown in (b), it is formed in a non-parallel state. FIG. 3A shows a configuration in which each boundary surface 5 is formed in a straight line, but gradually approaches as it goes in the −z direction. FIG. 3B shows each boundary surface. 5 illustrates a configuration formed so as to draw a gentle curved surface in which all or at least a part of the shape of 5 is in a non-linear state.

  Therefore, the length of each boundary surface 5 is extended by a non-parallel state as compared with a conventional polarizer configured such that each boundary surface 5 is in a straight line state and parallel to each other. Therefore, a sufficient area of the boundary surface that is a contact portion between the conductor 4 and the dielectric 3 can be secured, and the adhesion between the conductor 4 and the dielectric 3 can be improved. In particular, when at least a part of the shape of the boundary surface 5 when viewed from the plane direction (−y direction) is set to a non-linear state as shown in FIG. Therefore, the adhesion between the conductor 4 and the dielectric 3 can be further improved.

  As the adhesiveness is improved, the polarization characteristics of the polarizer 1 can be stabilized, and the polarizer can be prevented from being broken during the machining and assembly process. The reliability of the child 1 can also be improved.

  Next, the manufacturing method of the polarizer 1 is demonstrated, referring FIGS. First, as shown in FIG. 5, a dielectric base layer 6 having a predetermined thickness is formed on a surface of the substrate 2 from a dielectric material by sputtering or vacuum deposition. Next, a striped mask is placed on the surface of the dielectric base layer 6 and arranged in parallel at predetermined intervals as shown in FIG. 6 by X-ray lithography, ECR, etching, electron beam drawing technology, or the like. A plurality of dielectric base stripes 3a, 3a ... are formed at predetermined intervals.

  By applying molecular beam epitaxy (MBE), atomic layer epitaxy (ALE), sputtering, vacuum deposition, or the like to the dielectric base stripes 3a, 3a, etc., as shown in FIG. The conductive thin films 4a, 4a, ... are formed in contact with the side surfaces of the dielectric base stripes 3a, 3a ... in the form of a thin film. Since this metal is blown exclusively from one side to the one side of the dielectric base stripes 3a, 3a, etc., the conductive thin films 4a, 4a, etc. can be formed thin and precisely. However, although the conductive metal also adheres to the upper surfaces of the dielectric base stripes 3a, 3a, this is removed in a later step.

  After the conductor thin films 4a, 4a, etc. are formed, as shown in FIG. 8, the dielectric material 7 of the same material as the dielectric base stripes 3a, 3a,. Fill the remaining space of the body base stripes 3a, 3a ... Next, as shown in FIG. 9, excess dielectric material 7 and conductive thin films 4a, 4a,... Are removed by polishing or the like until the upper surfaces of the dielectric base stripes 3a, 3a,. The conductors 4 and 4 are formed by removing the conductive metal adhering to the upper surfaces of the dielectric base stripes 3a, 3a.

  The dielectric material 7 forms dielectric additional layers 3b, 3b... And the dielectrics 3, 3... From the dielectric additional layers 3b, 3b. . A polarizing film 8 having a stripe structure in which a plurality of dielectrics 3, 3... And conductors 4, 4 are alternately arranged can be formed.

  In the polarizer 1, the non-parallel shape formed on the side surface of the dielectric base stripe 3 a at the time of pattern transfer using the mask and exposure / development is used as the boundary surface 5 as it is. In addition, the side surfaces of the conductive thin films 4a, 4a,... Formed by scattering are not strictly in a parallel state, but are in a non-parallel state like the boundary surface 5. In this way, the non-parallel shape formed on the side surfaces of the conductive thin films 4a, 4a... When the conductive thin films 4a, 4a. Furthermore, since the conductor thin film 4a is formed in a non-parallel shape, the side surface of the embedded dielectric material 7 is also formed in a non-parallel state in accordance with the side surface shape of the conductor thin film 4a. Therefore, in the present embodiment, the polarizer 1 is formed while the boundary surface 5 between the conductor 4 and the dielectric 3 is in a non-parallel state, and accordingly, the manufacturing tolerance can be set moderately. Simplification and cost reduction can be achieved. In addition, as a method of forming the dielectric base stripes 3a, 3a,..., Laser ablation, pattern transfer by pressing, or the like may be used.

  The polarization operation of the polarizer 1 manufactured as described above will be described with reference to FIG. When non-polarized light is incident on the polarizer 1, a polarization component (TE polarized light) 9 whose electric field is parallel to the z direction in the incident light is reflected or absorbed. On the other hand, a polarized light component (TM polarized light) 10 whose electric field is parallel to the x direction passes through the dielectric 3 and is emitted from the polarizer 1.

  In the TE polarized light 9, the length (height H) of the conductor 4 is long enough to act as a conductor compared to the wavelength of incident light, so that a transient current flows through the conductor 4. As a result, since the reflection and absorption performance similar to the phenomenon on the metal surface is obtained, the TE polarized light 9 does not pass through the polarizer 1. On the other hand, in TM polarized light 10, since the length (width W) of the conductor 4 is shorter than the wavelength, it does not substantially act as a conductor, and no transient current flows through the conductor 4. Therefore, the TM polarized light 10 is transmitted through the polarizer 1.

  Either the dielectric 3 or the conductor 4 can be replaced with a semiconductor such as Si.

  In the polarizer 1, the polarizing film 8 has been described with an example in which a plurality of dielectrics 3, 3... And conductors 4, 4. Instead of..., The polarizing film 8 may be configured by forming a dielectric film so as to cover the conductors 4, 4.

<Second Embodiment>
Next, a polarizer 11 according to a second embodiment of the present invention will be described with reference to FIGS. FIG. 10 is a front view schematically showing the polarizer of the second embodiment of the present invention, FIG. 11 is a plan view of the polarizer of FIG. 10, and FIG. FIG. Note that the x-axis to z-axis shown in FIGS. 10 to 12 correspond to each other. Note that the description relating to the polarizer 11 of the second embodiment is mainly different from the polarizer 1 of the first embodiment, and duplicated portions are denoted by the same reference numerals and description thereof is omitted or simplified. To do.

  The second embodiment is different from the first embodiment in that the dielectric 3 is not provided, and a plurality of concave grooves 14 are engraved side by side on the surface of the light-transmitting substrate 12. The conductor 4 is directly embedded in the groove 14 to provide the stripe-shaped polarizing portion 13. Therefore, the conductor 4 is fixed by contacting the groove portion 14.

  A method for manufacturing such a polarizer 11 will be described with reference to FIG. First, as shown in FIG. 2A, a plurality of concave grooves 14 are formed on the surface of the optically transparent substrate 12. Examples of the method of forming the groove 14 include a method of performing dry etching or wet etching after exposure by a photolithography exposure technique, an electron beam drawing technique, a laser two-beam interference exposure technique, or the like. In addition, laser ablation that is a method capable of forming a fine concavo-convex structure, a pattern transfer method using a press, or the like may be used. By these methods, the groove portions 14 having a width W and a depth H are formed at the interval d.

  Next, the conductor 4 is embedded in the groove portion 14 as shown in FIG. As the burying method, electroless plating is suitable.

  In the polarizer 11 according to this embodiment, the non-parallel shape formed on the side surface in the groove portion 14 in the step of forming the groove portion 14 is used as the boundary surface 5 as it is. Accordingly, when each boundary surface 5 between the conductor 4 and the groove portion 14 of the polarizer 11 is enlarged and observed, the boundary surfaces 5 are not parallel to each other, and are shown in FIG. 3 (a) or FIG. 3 (b). Thus, it is formed to be in a non-parallel state.

  Therefore, since the length of each boundary surface 5 is extended by the amount of non-parallel, a sufficient area of the boundary surface 5 that is a contact portion between the conductor 4 and the groove portion 14 can be secured. The adhesion with the substrate 12 can be improved. In particular, when at least a part of the shape of the boundary surface 5 when viewed from the plane direction is set to a curved surface as shown in FIG. 3B, the area of the boundary surface 5 can be made larger than the linear shape. Therefore, the adhesion between the conductor 4 and the substrate 12 can be further improved.

  As the adhesion improves, the polarization characteristics of the polarizer 11 can be stabilized, and the polarizer can be prevented from being broken during the machining or assembly process. The reliability of the child 11 can also be improved.

  Furthermore, in the present embodiment, the polarizer 11 is formed while the boundary surface 5 is in a non-parallel shape. Therefore, the manufacturing tolerance can be set moderately, and the manufacturing can be facilitated and the cost can be reduced. It becomes possible.

  The conductor 4 may be replaced with a semiconductor such as Si.

<Third Embodiment>
Next, a polarizer 15 according to a third embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a front view schematically showing a polarizer according to the third embodiment of the present invention, FIG. 14 is a plan view of the polarizer of FIG. 13, and FIG. FIG. Note that the x-axis to z-axis shown in FIGS. 13 to 15 correspond to each other. Note that the description of the polarizer 11 of the third embodiment is mainly different from the polarizers 1 and 11 of the above-described embodiments, and duplicated portions are denoted by the same reference numerals and description thereof is omitted or simplified. To do.

  The third embodiment is different from each of the above embodiments in that a plurality of concave groove portions 14 are engraved on the surface of the light-transmitting substrate 12, and are formed on the surface of the substrate 16 including the groove portions 14. A thin film-like dielectric 3 is provided uniformly, and the conductor 4 is directly embedded in the second groove 18 formed by the dielectric 3, thereby providing a stripe-shaped polarizing portion 17. It is a point. Therefore, the conductor 4 is fixed by contacting the groove 18.

  A method for manufacturing such a polarizer 15 will be described with reference to FIG. First, as shown in FIG. 2A, a plurality of concave grooves 14 are formed on the surface of the optically transparent substrate 16. Examples of the method of forming the groove 14 include a method of performing dry etching or wet etching after exposure by a photolithography exposure technique, an electron beam drawing technique, a laser two-beam interference exposure technique, or the like. In addition, laser ablation that is a method capable of forming a fine concavo-convex structure, a pattern transfer method using a press, or the like may be used.

  Next, as shown in FIG. 2B, a thin film layer of the dielectric 3 is formed on the surface of the groove 14 and the substrate 16. The dielectric 3 is formed by a liquid phase deposition method or the like. Specifically, the substrate 16 is brought into contact with a solution containing a dielectric component in a supersaturated state (hereinafter referred to as a processing solution), and the dielectric component in the processing solution is deposited on the surfaces of the groove 14 and the substrate 16. Two groove portions 18 are formed. As a result, grooves 18 having a width W and a depth H are formed at the interval d.

  Next, the conductor 4 is embedded in the groove 18 as shown in FIG. For this embedding method, electroless plating is suitable. However, after applying a solution containing a conductor component on the layer of the dielectric 3, the conductor 4 is embedded in the second groove 18 by heating. May be.

  Examples of the method for applying the solution include a casting method, a dip coating method, a gravure coating method, a flexographic printing method, a roll coating method, a spray method, and a spin coating method.

  In this method, since the conductor 4 remains on the surface of the convex portion formed in a pair with the groove portion 18, the conductor remaining on the surface of the convex portion after the conductor 4 is buried can be removed by polishing, etching, or the like. It ’s fine.

  Theoretically, it is assumed that the dielectric three layers are isotropically deposited in the groove 14 by the liquid phase deposition method, but the actual liquid phase deposition method is not completely isotropic. The side surface of the second groove portion 18 is formed in a non-parallel state. In the polarizer 15 according to the present embodiment, the non-parallel shape is used as the boundary surface 5 as it is. Accordingly, when the boundary surfaces 5 between the conductor 4 and the dielectric 3 of the polarizer 15 are enlarged and observed, the boundary surfaces 5 are not parallel to each other, and are not shown in FIG. 3 (a) or FIG. 3 (b). As shown, it is formed in a non-parallel state.

  Accordingly, since the length of each boundary surface 5 is extended by the amount of non-parallel, a sufficient area of the boundary surface 5 that is a contact portion between the conductor 4 and the dielectric 3 can be secured. It is possible to improve the adhesion between the dielectric 3 and the dielectric 3. In particular, when at least a part of the shape of the boundary surface 5 when viewed from the plane direction is set to a curved surface as shown in FIG. 3B, the area of the boundary surface 5 can be made larger than the linear shape. Therefore, the adhesion between the conductor 4 and the dielectric 3 can be further improved.

  As the adhesion improves, the polarization characteristics of the polarizer 15 can be stabilized, and the polarizer can be prevented from being broken during the machining or assembly process. The reliability of the child 15 can also be improved.

  Furthermore, in the present embodiment, the polarizer 15 is formed with the boundary surface 5 remaining in a non-parallel shape, so that the manufacturing tolerance can be set moderately, thereby facilitating the manufacturing and reducing the cost. It becomes possible.

  Note that either the dielectric 3 or the conductor 4 can be replaced with a semiconductor such as Si.

<Fourth Embodiment>
Next, a polarizer 19 according to a fourth embodiment of the present invention will be described with reference to FIGS. FIG. 16 is a front view schematically showing a polarizer according to the fourth embodiment of the present invention, FIG. 17 is a plan view of the polarizer of FIG. 17, and FIG. FIG. The x-axis to z-axis shown in FIGS. 16 to 18 correspond to each other. The description related to the polarizer 19 of the fourth embodiment is mainly different from the polarizers 1, 11, and 15 of the above-described embodiments, and overlapping portions are denoted by the same reference numerals, and description thereof is omitted or simplified. Describe.

  The fourth embodiment is different from the above embodiments in that the dielectric 3 is not provided, and a plurality of concave groove portions 22 are engraved side by side on the surface of the light-transmitting substrate 20. The polarizing part 21 is configured and provided by directly forming the conductor 4 on the side surface in the inner part 22. Therefore, the conductor 4 is fixed by contacting the side surface of the groove 22.

  A method for manufacturing such a polarizer 19 will be described with reference to FIG. First, as shown in FIG. 2A, a plurality of concave groove portions 22 are formed on the surface of the optically transparent substrate 20. Examples of the method for forming the groove 22 include a method of performing dry etching or wet etching after exposure by a photolithography exposure technique, an electron beam drawing technique, a laser two-beam interference exposure technique, or the like. In addition, laser ablation that is a method capable of forming a fine concavo-convex structure, a pattern transfer method using a press, or the like may be used. By these methods, the groove portion 22 having a depth of H is formed.

  Next, as shown in FIG. 2B, the conductor 4 is formed on the side surface of the groove 22 with a width W and a distance d from above the groove 22 by sputtering, CVD, electroless plating, or the like. The insertion loss of the polarizer 19 can be improved by removing the conductors on the top surface of the convex portion formed in a pair with the groove portion 22 and the bottom surface of the groove portion 22.

  In the polarizer 19 according to this embodiment, the non-parallel shape formed on the side surface in the groove portion 22 in the step of forming the groove portion 22 is used as the boundary surface 5 as it is. Therefore, when each boundary surface 5 between the conductor 4 and the groove 22 of the polarizer 19 is enlarged and observed, the boundary surfaces 5 are not parallel to each other, and are shown in FIG. 3 (a) or FIG. 3 (b). Thus, it is formed to be in a non-parallel state.

  Accordingly, since the length of each boundary surface 5 is extended by a non-parallel amount, a sufficient area of the boundary surface 5 that is a contact portion between the conductor 4 and the groove portion 22 can be secured. The adhesion with the substrate 20 can be improved. In particular, when at least a part of the shape of the boundary surface 5 when viewed from the plane direction is set to a curved surface as shown in FIG. 3B, the area of the boundary surface 5 can be made larger than the linear shape. Therefore, the adhesion between the conductor 4 and the substrate 20 can be further improved.

  As the adhesion improves, the polarization characteristics of the polarizer 19 can be stabilized, and the polarizer can be prevented from being broken during the machining or assembly process. The reliability of the child 19 can also be improved.

  Furthermore, in the present embodiment, the polarizer 19 is formed with the boundary surface 5 being non-parallel, so that the manufacturing tolerance can be set moderately, thereby facilitating the manufacturing and reducing the cost. It becomes possible.

  The conductor 4 may be replaced with a semiconductor such as Si.

  In addition, the shape of the groove portions 14 and 22 and the second groove portion 18 in each of the embodiments is not limited to a concave shape, and may be, for example, a triangular shape, and is not particularly limited.

  The polarizer of the present invention can be used in various optical elements and devices such as an optical isolator, an optical attenuator, and a polarizing beam splitter.

The perspective view which shows typically the polarizer which concerns on the 1st Embodiment of this invention. The top view of the polarizer of FIG. The partial enlarged plan view which expanded a part of boundary surface of the conductor and dielectric or conductor and board | substrate in the polarizer of this invention. The front view which shows the polarization operation | movement of the polarizer of FIG. Explanatory drawing which shows the formation process of a dielectric base layer. Explanatory drawing which shows the process of forming a dielectric base stripe. Explanatory drawing which shows the process of forming a conductor thin film. Explanatory drawing which shows the process of embedding dielectric material. Explanatory drawing which shows the removal process of the dielectric material and the excess part of a conductor thin film. The front view which shows typically the polarizer which concerns on the 2nd Embodiment of this invention. The top view of the polarizer of FIG. Explanatory drawing which shows the manufacturing process of the polarizer of 2nd Embodiment. The front view which shows typically the polarizer which concerns on the 3rd Embodiment of this invention. The top view of the polarizer of FIG. Explanatory drawing which shows the manufacturing process of the polarizer of 3rd Embodiment. The front view which shows typically the polarizer which concerns on the 4th Embodiment of this invention. The top view of the polarizer of FIG. Explanatory drawing which shows the manufacturing process of the polarizer of 4th Embodiment. The front view which shows an example of the conventional polarizer. FIG. 20 is a front view showing a polarization operation of the polarizer of FIG. 19. The top view of the polarizer of FIG.

Explanation of symbols

1, 11, 15, 19 Polarizers 2, 12, 16, 20 Substrate 3 Dielectric 4 Conductor 5 Interface 6 Dielectric base layer 7 Dielectric material 8 Polarizing film 9 TE polarized light
10 TM polarized light
13, 17, 21 Polarizer
14, 22 Groove
18 Second groove

Claims (7)

In a polarizer comprising a light transmissive substrate, and a polarizing film having a stripe structure composed of a conductor and a light transmissive dielectric on the substrate surface,
A polarizer, wherein a plurality of boundary surfaces between a conductor and a dielectric are formed in a non-parallel state. In a polarizer having a light-transmitting substrate and a plurality of grooves engraved on the substrate surface, and having a stripe-shaped polarizing section by embedding a conductor in the grooves,
A polarizer characterized in that a plurality of boundary surfaces between a conductor and a groove are formed in a non-parallel state.   The polarizer according to claim 2, wherein the conductor is embedded in a second groove formed by a dielectric uniformly provided on a surface of the groove. In a polarizer comprising a light transmissive substrate and a plurality of grooves engraved on the surface of the substrate, and a polarizing portion configured by forming a conductor on a side surface of the groove,
A polarizer characterized in that a plurality of boundary surfaces between a conductor and a groove are formed in a non-parallel state.   The polarizer according to claim 1, wherein the conductor is replaced with a semiconductor.   4. The polarizer according to claim 1, wherein one of the conductor and the dielectric is replaced with a semiconductor. The polarizer according to claim 1, wherein at least a part of the boundary surface is formed in a non-linear state.

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