JP2006064871A - Polarized light converting element and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarized light conversion element which is durable against light and heat. <P>SOLUTION: The polarized light conversion element is equipped with a polarized light separating film 122 which is a plate type polarized light conversion element 101 having an incidence surface 102 where light 151 is made incident and a light emitting surface 103 parallel to the incidence surface 102, and transmits one of S-polarized light and P-polarized light and reflects the other, a filmy azimuth rotator 112 which rotates the plane of polarization of light and is made of an inorganic material, and a reflecting film 123 which reflects the light; and the polarized light separating film 122, azimuth rotator 112, and reflecting film 123 are disposed between the incidence surface 102 and light emitting surface 103, tilt to the incidence surface 102 and light emitting surface 103, and are arranged periodically in parallel to the incidence surface 102. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polarization conversion element and a method for manufacturing the same. In particular, the present invention relates to a polarization conversion element that converts non-polarized light from a lamp light source into polarized light in one direction and a method for manufacturing the same.

  For example, Patent Document 1 and Patent Document 2 disclose polarization conversion elements that convert non-polarized light into polarized light in one direction. The polarization conversion element disclosed in Patent Document 1 is a conventional first polarization conversion element, and the polarization conversion element disclosed in Patent Document 2 is a conventional second polarization conversion element. The conventional first and second polarization conversion elements will be described. FIG. 17 is a cross-sectional view showing the configuration of the conventional first polarization conversion element, and FIG. 18 is a perspective view showing the configuration of the conventional first polarization conversion element. FIG. 19 is a cross-sectional view showing a configuration of a conventional second polarization conversion element.

  As shown in FIGS. 17 and 18, the conventional first polarization conversion element 601 includes a first substrate 604 and a first substrate 604 so as to form layers obliquely with respect to the light incident surface 602 and the light emitting surface 603. The second substrates 605 are alternately arranged. In the first substrate 604, a polarization separation film 606 is formed on one surface on the second substrate 605 side, and a reflection film 607 is formed on the other surface, and these and the second substrate 605 are formed of an adhesive layer. It is bonded via 608. In addition, an optical rotator (half-wave plate) 609 is disposed on the emission surface 603 so as to cover the second substrate 605. In the polarization conversion element 601 having such a configuration, incident light 610 that is random polarization including P polarization and S polarization is polarized to S polarization.

  Further, as shown in FIG. 19, the conventional second polarization conversion element 701 has one of the layers formed in an oblique direction of about 45 degrees with respect to the light incident surface 702 and the light emitting surface 703. A plurality of transparent substrates 704 each having a polarization separation film 706 formed on the surface thereof are disposed. Further, an optical rotator (1/2 wavelength plate) 709 is disposed between the substrate 704 and the polarization separation films 706 every other layer. Is arranged. The polarization separation film 706 and the optical rotator 709 are bonded to the substrate 704 and the optical rotator 709 via an adhesive layer 708 made of an adhesive. Further, an antireflection film 711 is formed on the emission surface 703. In such a polarization conversion element 701, the incident light 710, which is random polarization including P polarization and S polarization, is polarized to S polarization.

In the conventional first polarization conversion element 601 and the conventional second polarization conversion element 701, the optical rotator 609 and the optical rotator 709 are, for example, birefringence having a birefringence of ½ of the wavelength of incident light. A plate may be used. The optical rotator 609 and the optical rotator 709 have a function of rotating the polarization direction of light incident on the polarization separation film 606 and the polarization separation film 706 to convert P polarization into S polarization and S polarization into P polarization. Yes. As the optical rotator 609 and the optical rotator 709, a stretched resin film obtained by stretching a plastic film such as polycarbonate or arton is used.
JP 2000-29812 A JP 2004-70299 A

  Usually, the polarization conversion element is used in the vicinity of a high-intensity lamp of a projector. For this reason, strong light is irradiated and the temperature becomes higher. As described above, since the conventional optical rotator is a resin film, when it receives strong light and heat, it deteriorates and deteriorates the transmittance and polarization conversion efficiency. In order to prevent this, a cooling structure and a filter for removing ultraviolet rays and near infrared rays have been installed. However, such a configuration has a problem of causing an increase in the number of parts, an increase in size, and an increase in cost of the entire projector. In addition, the resin film that is an optical rotator is thin and soft, so that it is difficult to handle, and it is difficult to adhere to a substrate or the like so that bubbles are not formed without distortion. For this reason, the polarization conversion element has a problem of poor productivity.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a polarization conversion element having resistance to light and heat.

  Furthermore, an object of this invention is to provide the manufacturing method which can manufacture the said polarization conversion element easily.

  The polarization conversion element of the present invention is a plate-like polarization conversion element having an incident surface on which light is incident and an exit surface parallel to the incident surface, and separates incident light into S-polarized light and P-polarized light. A polarization separation film that transmits one of polarized light and P-polarized light and reflects the other, a film-like optical rotator made of an inorganic material that rotates the polarization plane of light, and a reflective film that reflects light The polarization separation film, the optical rotator, and the reflection film are located between the incident surface and the exit surface, are inclined with respect to the entrance surface and the exit surface, and are periodically in a direction parallel to the entrance surface. It is characterized by being arranged in.

  Further, in the first method for producing a polarization conversion element of the present invention, an optical rotator which is a metal oxide film is obliquely deposited on a first transparent substrate or a layer laminated on the first transparent substrate. To form a laminate, and the laminate produced in the laminate production step and the second transparent substrate are alternately laminated and bonded to form an adhesive body. A bonding step; and a cutting step of cutting the plate-shaped body by cutting the bonded body in a direction inclined with respect to the stacked body and the second transparent substrate after the bonding step.

  Further, in the second method for producing a polarization conversion element of the present invention, an optical rotator which is a metal oxide film is obliquely deposited on the first transparent substrate or a layer laminated on the first transparent substrate. The laminate manufacturing step for forming the laminate, the first laminate prepared in the laminate preparation step, and the second laminate having at least the second transparent substrate are alternately formed. A bonding step of laminating and bonding to form an bonded body, and after the bonding step, cutting the bonded body in a direction inclined with respect to the first stacked body and the second stacked body, Cutting step.

  The present invention can provide a polarization conversion element having resistance to light and heat, and can further provide a method for manufacturing a polarization conversion element capable of easily manufacturing such a polarization conversion element. .

  Since the polarization conversion element of the present invention uses an inorganic material as an optical rotator, it has resistance to light and heat.

  In the polarization conversion element of the present invention, preferably, the optical rotator is a metal oxide film having birefringence. The metal oxide film has high resistance to light and heat among inorganic materials, and also has high strength and adhesion. Therefore, the polarization conversion element of the present invention further has high resistance to light and heat, and also has high strength. Further, since the optical rotator can be produced by vapor deposition, it can be easily produced, and the productivity is improved.

  In the polarization conversion element of the present invention, preferably, the optical rotator is the metal oxide film having birefringence formed by oblique vapor deposition. High birefringence can be obtained by forming the metal oxide film by oblique deposition. Further, since the optical rotator is formed by oblique vapor deposition, the optical rotator can be easily formed. This increases productivity. In the oblique vapor deposition, a birefringent film that is an optical rotator can be easily formed by performing vapor deposition by setting the vapor deposition surface obliquely with respect to the vapor deposition source.

  In addition, the polarization conversion element of the present invention is preferably a first laminated body having a first transparent substrate and the optical rotator formed on one surface of the first transparent substrate, and a second transparent substrate. And a second laminate having a polarization separation film formed on one side of the second transparent substrate and a reflection film formed on the other side of the second transparent substrate, The laminated body and the second laminated body are inclined with respect to the incident surface and the exit surface, and are alternately laminated in a direction parallel to the incident surface and the exit surface, and the polarization separation film and the What is necessary is just to set it as the structure which the optical rotator opposes and the said reflecting film and the said 1st transparent substrate oppose.

  The polarization conversion element of the present invention preferably includes a first transparent substrate, the polarization separation film and the optical rotator sequentially formed on one surface of the first transparent substrate, and the first transparent substrate. A laminate having the reflective film formed on the other surface and a second transparent substrate, wherein the laminate and the second transparent substrate are inclined with respect to the incident surface and the exit surface, What is necessary is just to set it as the structure laminated | stacked alternately in the direction parallel to the said incident surface and the said output surface.

  In addition, the polarization conversion element of the present invention is preferably formed on the other surface of the first transparent substrate, the polarization separation film formed on one surface of the first transparent substrate, and the first transparent substrate. A first laminate having the optical rotator, a second transparent substrate, and a second laminate having a reflective film formed on one surface of the second transparent substrate. And the second stacked body are alternately stacked in a direction that is inclined with respect to the incident surface and the output surface and is parallel to the incident surface and the output surface. The transparent substrate and the polarization separation film face each other, and the optical rotator and the reflection film face each other. Accordingly, an optical rotator having a function of rotating the polarization axis (polarization plane) while maintaining linearly polarized light while light is transmitted twice is used. Therefore, the film thickness of the optical rotator can be reduced.

  In addition, the polarization conversion element of the present invention is preferably formed sequentially on the first transparent substrate, the polarization separation film formed on one surface of the first transparent substrate, and the other surface of the first transparent substrate. A laminated body having the optical rotator and the reflective film, and a second transparent substrate, wherein the laminated body and the second transparent substrate are inclined with respect to the incident surface and the outgoing surface, The layers are alternately stacked in a direction parallel to the entrance surface and the exit surface. Accordingly, an optical rotator having a function of rotating the polarization axis (polarization plane) while maintaining linearly polarized light while light is transmitted twice is used. Therefore, the film thickness of the optical rotator can be reduced.

  In addition, the polarization conversion element of the present invention is preferably a first laminate including a first transparent substrate, the reflective film and the optical rotator sequentially formed on one surface of the first transparent substrate, A second laminated body having a second transparent substrate and a polarization separation film formed on one side of the second transparent substrate, the first laminated body and the second laminated body, Inclined with respect to the entrance surface and the exit surface, and alternately stacked in a direction parallel to the entrance surface and the exit surface, the first transparent substrate and the polarization separation film are opposed to each other, The optical rotator and the second transparent substrate are opposed to each other. Accordingly, an optical rotator having a function of rotating the polarization axis (polarization plane) while maintaining linearly polarized light while light is transmitted twice is used. Therefore, the film thickness of the optical rotator can be reduced.

  In the first and second manufacturing methods of the polarization conversion element of the present invention, the optical rotator which is a metal oxide film is formed by oblique deposition, so that it has light resistance and heat resistance and high birefringence. It is possible to easily form an optical rotator having the property. Therefore, a high-quality polarization conversion element can be easily manufactured. Moreover, the pasting process of the thin and soft resin film becomes unnecessary as in the prior art, and the optical rotator can be formed uniformly and stably. Therefore, a high-quality polarization conversion element can be manufactured with high productivity.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
A polarization conversion element and a manufacturing method thereof according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration of a polarization conversion element according to Embodiment 1 of the present invention.

  In the polarization conversion element 101 of the first embodiment, the first stacked body 110 and the second stacked body 120 are alternately formed so as to form layers in an oblique direction with respect to the light incident surface 102 and the light emitting surface 103. It is a structure arranged periodically. The inclination of each layer with respect to the entrance surface 102 and the exit surface 103 may be about 45 degrees, for example. Further, an adhesive is applied between the first stacked body 110 and the second stacked body 120 to form an adhesive layer 108.

  The first stacked body 110 includes a first transparent substrate 111 and a film-like optical rotator 112 made of an inorganic material formed on one surface of the first transparent substrate 111. The second laminate 120 is formed on the second transparent substrate 121, the polarization separation film 122 formed on one surface of the second transparent substrate 121, and the other surface of the second transparent substrate 121. The reflective film 123.

  Further, the polarization separation film 122 and the optical rotator 112 are opposed to each other through the adhesive layer 108, and the reflective film 123 and the first transparent substrate 111 are opposed to each other through the adhesive layer 108.

  Incident light 151 emitted from the light source is randomly polarized light including P-polarized light and S-polarized light, and is incident on the incident surface 102 of the polarization conversion element 101 from a perpendicular direction. Incident light 151 passes through the first transparent substrate 111 and is separated into P-polarized light and S-polarized light by the polarization separation film 122. The polarization separation film 122 is, for example, a dielectric multilayer film, and has a characteristic of transmitting either the S-polarized light or the P-polarized light and reflecting the other. However, in the first embodiment, the polarized light separating film 122 transmits the P-polarized light and transmits the S-polarized light. It shall have the characteristic to reflect.

  Among the incident light 151, P-polarized light passes through the polarization separation film 122, travels straight, passes through the adhesive layer 108, and enters the optical rotator 112. Since the optical rotator 112 rotates the polarization direction of the light, the P-polarized light is converted to S-polarized light, passes through the first transparent substrate 111, and is emitted from the emission surface 103. The optical rotator 112 is a birefringent film having a function of rotating the polarization axis (polarization plane) while maintaining the incident linearly polarized light as linearly polarized light. Note that an optical rotator is generally a film that generates a phase difference of ½ wavelength, so it may be called a ½ wavelength plate or a λ / 2 plate. Since the optical rotator 112 is made of an inorganic material, it has heat resistance and light resistance.

  Of the incident light, the S-polarized light separated and reflected by the polarization separation film 122 travels substantially parallel to the incident surface 102 and the exit surface 103 in the second transparent substrate 121 and is reflected at a right angle by the reflection film 123. Then, the light passes through the second transparent substrate 121 and is emitted from the emission surface 103.

  Therefore, only S-polarized light is emitted from the emission surface 103. That is, the polarization conversion element 101 can convert random polarization light including P polarization and S polarization into S polarization.

  Next, a method for manufacturing the polarization conversion element 101 according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 2 is a diagram illustrating a vapor deposition apparatus for manufacturing the polarization conversion element according to Embodiment 1 of the present invention. FIG. 3 is a diagram showing an arrangement at the time of adhesion in the manufacturing process of the polarization conversion element according to Embodiment 1 of the present invention. FIG. 4 is a cross-sectional view showing a cutting position in the manufacturing process of the polarization conversion element according to Embodiment 1 of the present invention.

  First, the optical rotator 112 is formed on one surface of the first transparent substrate 111 which is a parallel substrate, and the first stacked body 110 is manufactured. This forming method will be described with reference to FIG. As shown in FIG. 2, the vacuum deposition apparatus 191 includes a chamber 190, a substrate holder 192, and a deposition source 193, and the substrate holder 192 and the deposition source 193 are installed in the chamber 190. The vacuum vapor deposition device 191 includes an exhaust pump, an electron gun, a substrate heating device, and the like, which are not shown.

  The first transparent substrate 111 is installed on the substrate holder 192. An optical rotator 112 is formed on the surface of the first transparent substrate 111 by vapor deposition using a vacuum vapor deposition device 191. As the first transparent substrate 111, white plate glass is used here as an example. When the first transparent substrate 111 is installed on the substrate holder 192, the first transparent substrate 111 is installed so as to be inclined with respect to the vapor deposition source 193 direction. That is, the first transparent substrate 111 is installed not to be perpendicular to the line connecting the first transparent substrate 111 and the vapor deposition source 193 but to be inclined. Thereby, the surface (surface on which the optical rotator 112 is formed) on the first transparent substrate 111 and the line connecting the first transparent substrate 111 and the vapor deposition source 193 are not perpendicular but inclined. By performing vapor deposition in this manner, so-called oblique vapor deposition can be performed, and the optical rotator 112 can be formed on the first transparent substrate 111. For example, the first transparent substrate 111 is installed such that the surface on which the first transparent substrate 111 is formed is about 60 degrees with respect to the direction of the vapor deposition source 193. Note that this inclination angle may be set as appropriate depending on the deposition conditions, film quality, productivity, and the like of the vapor deposition material. Moreover, the vapor deposition material vapor-deposited on the 1st transparent substrate 111 is not specifically limited, What is necessary is just the material which has birefringence by oblique vapor deposition, for example, should just use a tantalum oxide.

  The first transparent substrate 111 is placed on the substrate holder 192 and tantalum oxide, which is a vapor deposition material, is placed in the vapor deposition source 193. Next, the air in the chamber 190 is exhausted using an exhaust pump, and the inside of the chamber 190 is evacuated. During this time, the first transparent substrate 111 may be heated using a substrate heating device. By heating the first transparent substrate 111, the adhesion between the first transparent substrate 111 and the deposited film can be increased, so that the strength of the film can be increased. After the inside of the chamber 190 is evacuated, the vapor deposition source 193 is heated to melt and evaporate the vapor deposition material. The evaporated vapor deposition material is incident on the surface of the first transparent substrate 111 from an oblique direction. Thereby, the vapor deposition material adheres as a film on the surface of the first transparent substrate 111. This film has a different refractive index depending on the direction, that is, a film having birefringence. Specifically, in FIG. 2, the refractive index is different in the vertical direction and in the direction perpendicular to the paper surface. In this way, the oblique deposition is continued until the film formed on the first transparent substrate 111 has a film thickness that can be used in the polarization conversion element 101 and generates a phase difference of ½ wavelength of light. . Before and after the formation of this film, the weather resistance and damage resistance of the base film for improving the adhesion between the first transparent substrate 111 and this film (optical rotator 112) and the birefringent film are improved. A protective film for improvement may be formed. In this manner, a film that is the optical rotator 112 is formed on the first transparent substrate 111.

  Thus, in the first embodiment, the optical rotator 112 is not a soft resin film but a metal oxide film formed on the surface of the first transparent substrate 111. Therefore, since defects such as distortion and bubble entrainment during film bonding do not occur, manufacturing is easy and productivity is high. Further, by using oblique vapor deposition, the optical rotator 112 can be formed on the entire surface of the first transparent substrate 111 at a time. For this reason, the time required for manufacturing the conventional first polarizing element shown in FIG. 17 and FIG. 18 is shortened because a time-consuming process of precisely bonding a large number of optical rotators at fine intervals is unnecessary. It is possible to reduce defective products and reduce costs.

  The optical rotator 112 may be any inorganic material. Among them, metal oxides have particularly high heat resistance and light resistance, and also have high adhesion and strength. In addition, a film formed by oblique deposition has an effect of having high birefringence. In addition to tantalum oxide, for example, niobium oxide, titanium oxide, zirconium oxide, and aluminum oxide may be used as the metal oxide.

  Next, the second stacked body 120 is manufactured. A reflective film 123 made of, for example, an aluminum or chromium film or a dielectric multilayer film is formed on one surface of the second transparent substrate 121 made of white glass. Next, a polarization separation film 122 made of a dielectric multilayer film is formed on the opposite surface of the second transparent substrate 121. In this way, the second stacked body 120 is produced. In these film formations, the vacuum vapor deposition apparatus 191 shown in FIG. 2 may be used. In this case, oblique vapor deposition is not performed. That is, the second transparent substrate 121 may be installed so as to be perpendicular to the direction of the vapor deposition source 193 and vapor deposition may be performed. In addition to vapor deposition, for example, film formation may be performed using sputtering or the like.

  Next, as shown in FIG. 3, a plurality of first stacked bodies 110 and second stacked bodies 120 are alternately arranged. At this time, the polarization separation film 122 and the optical rotator 112 face each other, and the reflection film 123 and the first transparent substrate 111 face each other. Thus, each laminated body is adhere | attached using an adhesive agent so that the 1st laminated body 110 and the 2nd laminated body 120 may be arranged alternately. Thereby, the adhesive body 140 shown in FIG. 4 is obtained. Further, as shown in FIG. 4, films are formed on both surfaces of the adhesive 140 formed by alternately bonding the first stacked body 110 and the second stacked body 120. It is preferable to adhere the third transparent substrate 130 which is not formed. Thereby, after the polarization conversion element 101 is completed, the third transparent substrate 130 can be used as a fixing portion when attached to the optical device. In addition, after the polarization conversion element 101 is completed, the third transparent substrate 130 becomes an end portion. That is, the end portion that is likely to be chipped in the post-processing or polishing of the polarization conversion element 101 becomes the third transparent substrate 130 that does not control light. Therefore, the optical function is not affected when the polarization conversion element 101 is manufactured. In FIG. 4, the illustration of the adhesive layer 108 (see FIG. 1) is omitted for easy viewing, but in practice, the first stacked body 110, the second stacked body 120, and An adhesive layer 108 is formed on each bonding surface of the third transparent substrate 130 (see FIG. 1).

  Next, as shown in FIG. 4, the adhesive 140 is cut along a cutting line 141 in an oblique direction with respect to the surface of the first stacked body 110. For example, the cutting line 141 may be inclined in the direction of about 45 degrees with respect to the surface of the first stacked body 110. In FIG. 4, the cutting line 141 is indicated by a one-dot chain line. Since polishing or the like is performed after the cutting, the cutting interval is appropriately determined so that the thickness becomes an extra thickness after completion of the polarization conversion element 101 (see FIG. 1) in consideration of the amount. Note that the cutting line 141 is on the entrance surface 102 or the exit surface 103 side (see FIG. 1). For the cutting, for example, a wire saw, an outer peripheral blade cutting machine, an inner peripheral blade cutting machine, or the like can be used.

  Further, when the first laminated body 110 and the second laminated body 120 are arranged and bonded, as shown in FIGS. 3 and 4, the members are arranged so as to be shifted substantially in the same direction as the cutting direction. If bonded, the end material can be minimized and a large number of polarization conversion elements 101 can be manufactured.

  Next, since the cut plate has a rough cut surface, both the upper and lower surfaces are polished to a transparent surface to form the incident surface 102 and the output surface 103. The polarization conversion element 101 is manufactured through the above steps.

  According to the polarization conversion element of Embodiment 1 and the method for manufacturing the same, since the optical rotator 112 is formed on the first transparent substrate 111 by oblique vapor deposition, there is no need to bond a resin film as in the prior art. No distortion of resin film (optical rotator), entrainment of bubbles, or misalignment. Therefore, the optical rotator 112 can be easily formed with high accuracy.

  In addition, a projector using the polarization conversion element 101 according to Embodiment 1 was actually manufactured and a projection test was performed. As a result, in the conventional polarization conversion element using the optical rotator made of a resin film, the resin film was gradually discolored by being exposed to high-intensity light at a high temperature, and the transmittance and polarization conversion efficiency were deteriorated. However, in the polarization conversion element 101 of the first embodiment, the transmittance of the optical rotator 112 and the polarization conversion efficiency are hardly deteriorated, and the lifetime of the projector is improved.

(Embodiment 2)
A polarization conversion element and a method for manufacturing the same according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 5 is a cross-sectional view showing the configuration of the polarization conversion element according to Embodiment 2 of the present invention.

  In the polarization conversion element 201 of the second embodiment, the laminate 210 and the second transparent substrate 221 are alternately and periodically formed so that layers are formed in an oblique direction with respect to the light incident surface 202 and the light emitting surface 203. Arranged structure. The inclination of each layer with respect to the entrance surface 202 and the exit surface 203 may be about 45 degrees, for example. In addition, an adhesive is applied between the laminate 210 and the second transparent substrate 221, and an adhesive layer 208 is formed.

  The first laminated body 210 includes a first transparent substrate 211, a polarization separation film 213 sequentially formed on one surface of the first transparent substrate 211, and a film-like optical rotator 212 made of an inorganic material, And a reflective film 214 formed on the other surface of the transparent substrate 211. The optical rotator 212 and the reflective film 214 are opposed to the second transparent substrate 221 with the adhesive layer 208 interposed therebetween.

  Incident light 251 emitted from the light source is random polarized light including P-polarized light and S-polarized light, and is incident on the incident surface 202 of the polarization conversion element 201 from a perpendicular direction. Incident light 251 passes through the first transparent substrate 211 and is separated into P-polarized light and S-polarized light by the polarization separation film 213. The polarization separation film 213 is, for example, a dielectric multilayer film as in the first embodiment, and has a characteristic of transmitting P-polarized light and reflecting S-polarized light.

  Of the incident light 251, P-polarized light travels straight through the polarization separation film 213, enters the optical rotator 212, is converted to S-polarized light, passes through the adhesive layer 208, and passes through the second transparent substrate 221. Then, the light is emitted from the emission surface 203.

  Of the incident light 251, S-polarized light separated and reflected by the polarization separation film 213 travels substantially parallel to the incident surface 202 and the exit surface 203 in the first transparent substrate 211, and is reflected at a right angle by the reflective film 214. Then, the light passes through the first transparent substrate 211 and is emitted from the emission surface 203.

  Accordingly, only S-polarized light is emitted from the emission surface 203. That is, the polarization conversion element 201 can polarize random polarized light including P polarized light and S polarized light into S polarized light.

  Next, a method for manufacturing the polarization conversion element 201 according to Embodiment 2 will be described with reference to FIGS. FIG. 6 is a cross-sectional view showing an arrangement during bonding in the manufacturing process of the polarization conversion element according to Embodiment 2 of the present invention, and FIG. 7 is a cut in the manufacturing process of the polarization conversion element according to Embodiment 2 of the present invention. It is sectional drawing which shows a position.

  First, the polarization separation film 213 and the optical rotator 212 are sequentially formed on one surface of the first transparent substrate 211 that is a parallel substrate, and the reflective film 214 is formed on the other surface, whereby the laminate 210 is manufactured. Since it is not necessary to form a film on the second transparent substrate 221, the time and cost of the film forming process are not increased accordingly.

  As the first transparent substrate 211 and the second transparent substrate 221, for example, optical glass BK7 may be used. For the production of the stacked body 210, a vacuum evaporation apparatus 191 shown in FIG. Specifically, the first transparent substrate 211 is installed on the substrate holder 192 of the vacuum vapor deposition apparatus 191 shown in FIG. 2 so as to be perpendicular to the direction of the vapor deposition source 193, and the reflective film 214 is formed on one surface thereof. For example, an increased reflection aluminum mirror in which an increased reflection layer is added below aluminum is formed by vapor deposition. Next, a polarization separation film 213 is deposited on the opposite surface of the reflection film 214. Then, the first transparent substrate 211 is installed at an angle of about 70 degrees with respect to the direction of the vapor deposition source 193, for example, niobium oxide is obliquely deposited on the polarization separation film 213, and birefringence is formed on the polarization separation film 213. An optical rotator 212 which is a film is formed.

  Next, as illustrated in FIG. 6, a plurality of laminated bodies 210 and second transparent substrates 221 are alternately arranged, and the laminated bodies 210 and the second transparent substrates 221 are bonded using an adhesive. In FIGS. 6 and 7, the adhesive layer 208 is not shown for ease of viewing.

  Next, as illustrated in FIG. 7, an adhesive body 240 formed by alternately bonding the stacked body 210 and the second transparent substrate 221 is inclined in a direction oblique to the surface of the stacked body 210. Cut along the cutting line 241. For example, what is necessary is just to make it the cutting line 241 incline in the direction of about 45 degree | times with respect to the surface of the laminated body 210. FIG. In FIG. 7, the cutting line 241 is indicated by a one-dot chain line. Since the polishing or the like is performed after the cutting, the cutting interval is appropriately determined so that the thickness becomes an extra thickness after the completion of the polarization conversion element 201 (see FIG. 5). Note that the cutting line 241 is on the incident surface 202 or the exit surface 203 side (see FIG. 5). For the cutting, for example, a wire saw, an outer peripheral blade cutting machine, an inner peripheral blade cutting machine, or the like can be used.

  Further, when the laminated body 210 and the second transparent substrate 221 are arranged and bonded, as shown in FIGS. 6 and 7, the members are arranged while being shifted and arranged in substantially the same direction as the cutting direction. By doing so, the edge material can be minimized and a large number of polarization conversion elements 201 can be manufactured.

  Next, since the cut plate has a rough cut surface, both the upper and lower surfaces are polished to a transparent surface to form the incident surface 202 and the output surface 203. The polarization conversion element 201 is manufactured through the above steps.

  According to the polarization conversion element of Embodiment 2 and the manufacturing method thereof, since the optical rotator 212 is formed by vapor deposition on the polarization separation film 213 of the first transparent substrate 211, the resin films are bonded together as in the past. There is no need, and there is no distortion of the resin film (optical rotator), entrainment of bubbles, or misalignment. Therefore, the optical rotator 212 can be easily formed with high accuracy.

(Embodiment 3)
A polarization conversion element 301 and a method for manufacturing the same according to Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 8 is a cross-sectional view showing the configuration of the polarization conversion element according to Embodiment 3 of the present invention.

  In the polarization conversion element 301 according to the third embodiment, the first stacked body 310 and the second stacked body 320 are alternately formed so as to form layers in an oblique direction with respect to the light incident surface 302 and the light emitting surface 303. It is a structure arranged periodically. The inclination of each layer with respect to the entrance surface 302 and the exit surface 303 may be about 45 degrees, for example. In addition, an adhesive is applied between the first stacked body 310 and the second stacked body 320 to form an adhesive layer 308.

  The first stacked body 310 is formed on the first transparent substrate 311, the polarization separation film 313 formed on one surface of the first transparent substrate 311, and the other surface of the first transparent substrate 311. And a film-like optical rotator 312 made of an inorganic material. The second stacked body 320 includes a second transparent substrate 321 and a reflective film 322 formed on one surface of the second transparent substrate 321.

  Further, the second transparent substrate 321 and the polarization separation film 313 are opposed via the adhesive layer 308, and the optical rotator 312 and the reflective film 322 are opposed via the adhesive layer 308.

  Incident light 351 emitted from the light source is random polarized light including P-polarized light and S-polarized light, and is incident on the incident surface 302 of the polarization conversion element 301 from a perpendicular direction. Incident light 351 passes through the first transparent substrate 311 and is separated into P-polarized light and S-polarized light by the polarization separation film 313. The polarization separation film 313 is, for example, a dielectric multilayer film as in the first embodiment, and has a characteristic of transmitting P-polarized light and reflecting S-polarized light.

  Of the incident light 351, P-polarized light passes through the polarization separation film 313 and travels straight, passes through the adhesive layer 308 and the second transparent substrate 321, and is emitted from the emission surface 303.

  Of the incident light 351, the S-polarized light separated by the polarization separation film 313 travels substantially parallel to the incident surface 302 and the exit surface 303 in the first transparent substrate 311, enters the optical rotator 312, and is adhesive. The light passes through the layer 308, is reflected at a right angle by the reflective film 322, passes through the adhesive layer 308 and the optical rotator 312 again, passes through the first transparent substrate 311, and exits from the exit surface 303. S-polarized light enters the optical rotator 312, passes through the adhesive layer 308, is reflected at a further right angle at the reflective film 322, and is converted back to P-polarized light when passing through the adhesive layer 308 and the optical rotator 312 again. The Thus, the optical rotator 312 polarizes the light with two transmissions. Thereby, the optical rotator 312 can be made thinner than the case where light is polarized by one transmission (for example, the case shown in the first and second embodiments). Therefore, when the optical rotator 312 is formed by oblique vapor deposition, the material can be reduced and the manufacturing time can be shortened.

  As described above, only P-polarized light is emitted from the emission surface 303. That is, the polarization conversion element 301 can polarize random polarized light including P polarized light and S polarized light into P polarized light.

  Next, a method for manufacturing the polarization conversion element 301 according to Embodiment 3 will be described with reference to FIGS. FIG. 9 is a cross-sectional view showing an arrangement during bonding in the manufacturing process of the polarization conversion element according to Embodiment 3 of the present invention, and FIG. 10 is a cut in the manufacturing process of the polarization conversion element according to Embodiment 3 of the present invention. It is sectional drawing which shows a position.

  First, the polarization separation film 313 is formed on one surface of the first transparent substrate 311 that is a parallel substrate, and the optical rotator 312 is formed on the other surface, whereby the first stacked body 310 is manufactured. Next, a reflective film 322 is formed on one surface of the second transparent substrate 321 to produce a second stacked body 320.

  A vacuum deposition apparatus 191 illustrated in FIG. 2 may be used for manufacturing the first stacked body 310. Specifically, the first transparent substrate 311 is placed on the substrate holder 192 of the vacuum vapor deposition apparatus 191 shown in FIG. 2 so as to be perpendicular to the direction of the vapor deposition source 193, and the polarization separation film 313 is provided on one surface. Evaporate. Then, the first transparent substrate 311 is inclined at about 70 degrees with respect to the direction of the vapor deposition source 193, and the other surface is directed toward the vapor deposition source 193. For example, niobium oxide is obliquely vapor-deposited. Thus, an optical rotator 312 that is a birefringent film is formed on the other surface of the first transparent substrate 311. As described above, since the optical rotator 312 may be thin, the time required for vapor deposition is short and the vapor deposition material can be reduced.

  Next, the second stacked body 320 is manufactured. Similarly to the manufacture of the first stacked body 310, a vacuum evaporation apparatus 191 illustrated in FIG. The second transparent substrate 321 is installed on the substrate holder 192 of the vacuum vapor deposition apparatus 191 so as to be perpendicular to the direction of the vapor deposition source 193, and as a reflection film 322 on one surface, for example, an increased reflection layer under aluminum A reflection-enhancing aluminum mirror to which is added is formed by vapor deposition.

  Next, as shown in FIG. 10, a plurality of first stacked bodies 310 and second stacked bodies 320 are alternately arranged. At this time, the second transparent substrate 321 and the polarization separation film 313 are opposed to each other, and the optical rotator 312 and the reflection film 322 are opposed to each other. Thus, each laminated body is adhere | attached using an adhesive agent so that the 1st laminated body 310 and the 2nd laminated body 320 may be arranged by turns. Thereby, the adhesive body 340 shown in FIG. 10 is obtained. Further, as shown in FIG. 10, films are formed on both sides of the adhesive body 340 formed by alternately bonding the first stacked body 310 and the second stacked body 320. It is preferable to adhere the third transparent substrate 330 which is not formed. Thereby, after the polarization conversion element 301 is completed, the third substrate 330 can be used as a fixing portion when attached to the optical device. In the polarization conversion element 301, the third substrate 330 is an end portion. That is, the end portion that is likely to be chipped in the subsequent process of cutting or polishing in the polarization conversion element 301 becomes the third substrate 330 that does not control light. Therefore, the optical function is not affected when the polarization conversion element 301 is manufactured. In FIG. 10, the illustration of the adhesive layer 308 (see FIG. 8) is omitted for the sake of easy viewing, but in practice, the first stacked body 310, the second stacked body 320, and An adhesive layer 308 is formed on each bonding surface of the third transparent substrate 330 (see FIG. 8).

  Next, as shown in FIG. 10, the adhesive 340 is cut along a cutting line 341 in a direction oblique to the surface of the first substrate 310. For example, the cutting line 341 may be inclined about 45 degrees with respect to the surface of the first substrate 310. In FIG. 10, the cutting line 341 is indicated by a one-dot chain line. Since the polishing or the like is performed after the cutting, the cutting interval is appropriately determined so that the thickness becomes an extra thickness after the polarization conversion element 301 is completed (see FIG. 8) in consideration of the amount. Note that the cutting line 341 is on the entrance surface 302 or the exit surface 303 side (see FIG. 8). For the cutting, for example, a wire saw, an outer peripheral blade cutting machine, an inner peripheral blade cutting machine, or the like can be used.

  Further, when the first laminated body 310 and the second laminated body 320 are arranged and bonded, as shown in FIGS. 9 and 10, the members are arranged so as to be shifted in the substantially same direction as the cutting direction. Then, the end material can be suppressed to a minimum and a large number of polarization conversion elements 301 can be manufactured.

  Next, since the cut plate has a rough cut surface, both the upper and lower surfaces are polished to a transparent surface to form an incident surface 302 and an output surface 303. The polarization conversion element 301 is manufactured through the above steps.

  According to the polarization conversion element of Embodiment 3 and the method for manufacturing the same, since the optical rotator 312 is formed on the first transparent substrate 311 by oblique vapor deposition, there is no need to bond a resin film as in the prior art. No distortion of resin film (optical rotator), entrainment of bubbles, or misalignment. Therefore, the optical rotator 312 can be easily formed with high accuracy.

  In addition, as described above, the optical rotator 312 has a function of rotating the polarization axis (polarization plane) while maintaining linearly polarized light while light is transmitted twice. In addition, the film thickness is thinner than the optical rotators 112 and 212 of the polarization conversion elements 101 and 201 of the second embodiment. Therefore, since the film formation time of the optical rotator 312 which is a birefringent film can be shortened, a cheaper polarization separation element 301 can be realized.

(Embodiment 4)
A polarization conversion element and a manufacturing method thereof according to Embodiment 4 of the present invention will be described with reference to the drawings. FIG. 11 is a cross-sectional view showing the configuration of the polarization conversion element according to Embodiment 4 of the present invention.

  In the polarization conversion element 401 of the fourth embodiment, the laminate 410 and the fourth transparent substrate 221 are alternately and periodically formed so as to form layers in an oblique direction with respect to the light incident surface 402 and the light emitting surface 403. Arranged structure. The inclination of each layer with respect to the entrance surface 402 and the exit surface 403 may be about 45 degrees, for example. In addition, an adhesive is applied between the stacked body 410 and the second transparent substrate 421 to form an adhesive layer 408.

  The first stacked body 410 is sequentially formed on the first transparent substrate 411, the polarization separation film 413 formed on one surface of the first transparent substrate 411, and the other surface of the first transparent substrate 411. A film-like optical rotator 412 and a reflective film 414 made of an inorganic material. The polarization separation film 413 and the reflection film 414 are opposed to the second transparent substrate 421 with the adhesive layer 408 interposed therebetween.

  Incident light 451 emitted from the light source is random polarized light including P-polarized light and S-polarized light, and is incident on the incident surface 402 of the polarization conversion element 401 from a perpendicular direction. Incident light 451 passes through the first transparent substrate 411 and is separated into P-polarized light and S-polarized light by the polarization separation film 413. As in the first embodiment, the polarization separation film 413 is, for example, a dielectric multilayer film, and has a characteristic of transmitting P-polarized light and reflecting S-polarized light.

  Of the incident light 451, P-polarized light passes through the polarization separation film 413 and travels straight, passes through the adhesive layer 408 and the second transparent substrate 421, and is emitted from the emission surface 403.

  Of the incident light 451, S-polarized light separated by the polarization separation film 413 travels substantially parallel to the incident surface 402 and the exit surface 403 in the first transparent substrate 411, and enters the optical rotator 412. The light is reflected at right angles by 414, enters the optical rotator 412 again, passes through the first transparent substrate 411, and exits from the exit surface 403. The S-polarized light enters the optical rotator 412, is reflected by the reflection film 414, and is converted to P-polarized light again when passing through the optical rotator 412. Thus, the optical rotator 412 polarizes the light with two transmissions. Thereby, the optical rotator 412 can be made thinner than in the case where the light is polarized by one transmission (for example, the case shown in the first and second embodiments). Therefore, when the optical rotator 412 is formed by oblique deposition, the material can be reduced and the manufacturing time can be shortened.

  As described above, only the P-polarized light is emitted from the emission surface 403. That is, the polarization conversion element 401 can polarize random polarized light including P polarized light and S polarized light into P polarized light.

  Next, a method for manufacturing the polarization conversion element 401 according to Embodiment 4 will be described with reference to FIGS. FIG. 12 is a cross-sectional view showing an arrangement at the time of bonding in the manufacturing process of the polarization conversion element according to Embodiment 4 of the present invention, and FIG. 13 is a cut in the manufacturing process of the polarization conversion element according to Embodiment 4 of the present invention. It is sectional drawing which shows a position.

  First, the polarization separation film 413 is formed on one surface of the first transparent substrate 411 which is a parallel substrate, and the optical rotator 412 and the reflection film 414 are sequentially formed on the other surface, so that the stacked body 410 is manufactured. Since the second transparent substrate 421 does not need to be deposited, the deposition process does not take much time and cost.

  For the manufacture of the stacked body 410, a vacuum evaporation apparatus 191 shown in FIG. Specifically, the first transparent substrate 411 is installed on the substrate holder 192 of the vacuum vapor deposition apparatus 191 shown in FIG. 2 so as to be perpendicular to the direction of the vapor deposition source 193, and the polarization separation film 413 is provided on one surface. A film is formed by vapor deposition. Next, the first transparent substrate 411 is inclined at about 70 degrees with respect to the direction of the vapor deposition source 193, and the other surface faces the vapor deposition source 193. For example, niobium oxide is vapor-deposited obliquely, An optical rotator 412 that is a birefringent film is formed on the other surface of one transparent substrate 411. Then, the first transparent substrate 411 is placed again so as to be perpendicular to the direction of the vapor deposition source 193, and an enhanced reflection aluminum mirror is deposited on the optical rotator 412 as a reflection film 414 by adding a reflection enhancement layer below the aluminum. The film is formed by

  Next, as shown in FIG. 12, a plurality of laminated bodies 410 and second transparent substrates 421 are alternately arranged, and the laminated bodies 410 and the second transparent substrates 421 are bonded using an adhesive. In FIG. 12 and FIG. 13, the adhesive layer 408 is not shown for ease of viewing.

  Next, as illustrated in FIG. 13, an adhesive body 440 formed by alternately bonding the stacked body 410 and the second transparent substrate 421 is arranged in an oblique direction with respect to the surface of the stacked body 410. Cut along cutting line 441. For example, the cutting line 441 may be inclined about 45 degrees with respect to the surface of the stacked body 410. In FIG. 13, the cutting line 441 is indicated by a one-dot chain line. Since the polishing or the like is performed after the cutting, the cutting interval is appropriately determined so that the thickness becomes an extra thickness after the polarization conversion element 401 is completed (see FIG. 11) in consideration of the amount. Note that the cutting line 441 is on the entrance surface 402 or the exit surface 403 side (see FIG. 11). For the cutting, for example, a wire saw, an outer peripheral blade cutting machine, an inner peripheral blade cutting machine, or the like can be used.

  Further, when the laminated body 410 and the second transparent substrate 421 are arranged and bonded, as shown in FIGS. 12 and 13, the members are arranged while being shifted and arranged in substantially the same direction as the cutting direction. By doing so, it is possible to minimize the edge material and to manufacture a large number of polarization conversion elements 401.

  Next, since the cut plate has a rough cut surface, both the upper and lower surfaces are polished to a transparent surface to form an incident surface 402 and an output surface 403. The polarization conversion element 401 is manufactured through the above steps.

  According to the polarization conversion element of Embodiment 4 and the method of manufacturing the same, since the optical rotator 412 is formed on the first transparent substrate 411 by vapor deposition, there is no need to bond a resin film as in the prior art. No distortion of film (optical rotator), entrainment of bubbles, or misalignment. Therefore, the optical rotator 412 can be easily formed with high accuracy.

Further, as described above, the optical rotator 412 is configured to have a function of rotating the polarization axis (polarization plane) while maintaining linearly polarized light while light is transmitted twice. In addition, the film thickness is thinner than the optical rotators 112 and 212 of the polarization conversion elements 101 and 201 of the second embodiment. Therefore, since the film formation time of the optical rotator 412 that is a birefringent film can be shortened, a cheaper polarization separation element 401 can be realized.
(Embodiment 5)
A polarization conversion element 501 and a manufacturing method thereof according to Embodiment 5 of the present invention will be described with reference to the drawings. FIG. 14 is a cross-sectional view showing the configuration of the polarization conversion element according to Embodiment 5 of the present invention.

  In the polarization conversion element 501 of Embodiment 5, the first stacked body 510 and the second stacked body 520 are alternately formed so as to form layers in an oblique direction with respect to the light incident surface 502 and the light exit surface 503. It is a structure arranged periodically. The inclination of each layer with respect to the entrance surface 502 and the exit surface 503 may be about 45 degrees, for example. In addition, an adhesive is applied between the first stacked body 510 and the second stacked body 520 to form an adhesive layer 508.

  The first stacked body 510 includes a first transparent substrate 511, a reflective film 513 sequentially formed on one surface of the first transparent substrate 511, and a film-like optical rotator 512 made of an inorganic material. The second stacked body 520 includes a second transparent substrate 521 and a polarization separation film 522 formed on one surface of the second transparent substrate 321.

  Further, the first transparent substrate 511 and the polarization separation film 522 are opposed to each other through the adhesive layer 508, and the second transparent substrate 521 and the optical rotator 512 are opposed to each other through the adhesive layer 508.

  Incident light 551 emitted from the light source is random polarized light including P-polarized light and S-polarized light, and is incident on the incident surface 502 of the polarization conversion element 501 from a perpendicular direction. Incident light 551 passes through the first transparent substrate 521 and is separated into P-polarized light and S-polarized light by the polarization separation film 522. The polarization separation film 522 is, for example, a dielectric multilayer film as in the first embodiment, and has a characteristic of transmitting P-polarized light and reflecting S-polarized light.

  Of the incident light 551, P-polarized light passes through the polarization separation film 522 and travels straight, passes through the adhesive layer 508 and the first transparent substrate 511, and is emitted from the emission surface 503.

  The S-polarized light separated by the polarization separation film 522 travels in the second transparent substrate 521 substantially parallel to the incident surface 502 and the exit surface 503, passes through the adhesive layer 508, enters the optical rotator 512, The light is reflected at a right angle by the reflective film 513, passes through the optical rotator 512 again, passes through the adhesive layer 508 and the first transparent substrate 511, and exits from the exit surface 503. The S-polarized light enters the optical rotator 512, is reflected at a right angle by the reflection film 322, and is converted into P-polarized light again when passing through the optical rotator 512. Thus, the optical rotator 512 polarizes the light with two transmissions. Thereby, the optical rotator 512 can be made thinner than the case where light is polarized by one transmission (for example, the case shown in the first and second embodiments). Therefore, when the optical rotator 512 is formed by oblique vapor deposition, the material can be reduced and the manufacturing time can be shortened.

  As described above, only P-polarized light is emitted from the emission surface 503. That is, the polarization conversion element 501 can polarize random polarized light including P polarized light and S polarized light into P polarized light.

  Next, a method for manufacturing the polarization conversion element 501 according to Embodiment 5 will be described with reference to FIGS. FIG. 15 is a cross-sectional view showing an arrangement during bonding in the manufacturing process of the polarization conversion element according to Embodiment 5 of the present invention, and FIG. 16 is a cut in the manufacturing process of the polarization conversion element according to Embodiment 5 of the present invention. It is sectional drawing which shows a position.

  First, the reflective film 513 and the optical rotator 512 are sequentially formed on one surface of the first transparent substrate 511 which is a parallel substrate, and the first stacked body 510 is manufactured. Next, a polarization separation film 522 is formed on one surface of the second transparent substrate 521 to produce a second stacked body 520.

  A vacuum deposition apparatus 191 illustrated in FIG. 2 may be used for manufacturing the first stacked body 510. Specifically, the first transparent substrate 511 is installed on the substrate holder 192 of the vacuum vapor deposition apparatus 191 shown in FIG. 2 so as to be perpendicular to the direction of the vapor deposition source 193, and as a reflection film 513 on one surface, For example, an increased reflection aluminum mirror in which an increased reflection layer is added below aluminum is formed by vapor deposition. Then, the first transparent substrate 511 is inclined at about 70 degrees with respect to the direction of the vapor deposition source 193, and, for example, niobium oxide is obliquely vapor-deposited on the reflective film 513, and a birefringent film is formed on the reflective film 513. An optical rotator 512 is formed. As described above, since the optical rotator 512 may be thin, the time required for vapor deposition is short and the vapor deposition material can be reduced.

  Next, the second stacked body 520 is manufactured. Similarly to the manufacturing of the first stacked body 510, a vacuum evaporation apparatus 191 illustrated in FIG. The second transparent substrate 521 is placed on the substrate holder 192 of the vacuum vapor deposition apparatus 191 so as to be perpendicular to the direction of the vapor deposition source 193, and the polarization separation film 522 is vapor deposited on one surface.

  Next, as illustrated in FIG. 15, a plurality of first stacked bodies 510 and second stacked bodies 520 are alternately arranged. At this time, the first transparent substrate 511 and the polarization separation film 522 are opposed to each other, and the optical rotator 512 and the second transparent substrate 521 are opposed to each other. Thus, each laminated body is adhere | attached using an adhesive agent so that the 1st laminated body 510 and the 2nd laminated body 520 may be arranged alternately. Thereby, the adhesive body 540 shown in FIG. 16 is obtained. Further, as shown in FIG. 16, films are formed on both sides of the adhesive body 540 formed by alternately bonding the first stacked body 510 and the second stacked body 520. It is preferable to adhere the third transparent substrate 530 which is not formed. Thereby, after the polarization conversion element 501 is completed, the third substrate 530 can be used as a fixing portion when being attached to the optical apparatus. In the polarization conversion element 501, the third substrate 530 is an end portion. That is, the end portion that is likely to be chipped in the subsequent process of cutting and polishing in the polarization conversion element 501 becomes the third substrate 530 that does not control light. Therefore, the optical function is not affected when the polarization conversion element 501 is manufactured. In FIG. 16, the illustration of the adhesive layer 508 (see FIG. 14) is omitted for easy viewing, but actually, the first stacked body 510, the second stacked body 520, and An adhesive layer 508 is formed on each bonding surface of the third transparent substrate 530 (see FIG. 14).

  Next, as shown in FIG. 16, the adhesive body 540 is cut along a cutting line 541 in a direction oblique to the surface of the first stacked body 510. For example, the cutting line 541 may be inclined in the direction of about 45 degrees with respect to the surface of the first stacked body 510. In FIG. 16, the cutting line 541 is indicated by a one-dot chain line. Since polishing or the like is performed after the cutting, the cutting interval is appropriately determined so that the thickness becomes an extra thickness after the polarization conversion element 501 is completed (see FIG. 14) in consideration of the amount. Note that the cutting line 541 is on the entrance surface 502 or the exit surface 503 side (see FIG. 14). For the cutting, for example, a wire saw, an outer peripheral blade cutting machine, an inner peripheral blade cutting machine, or the like can be used.

  Further, when the first laminated body 510 and the second laminated body 520 are arranged and bonded, as shown in FIGS. 15 and 16, the respective members are arranged so as to be shifted in the same direction as the cutting direction. If bonded, the edge material can be minimized and a large number of polarization conversion elements 501 can be manufactured.

  Next, since the cut plate has a rough cut surface, both the upper and lower surfaces are polished to a transparent surface to form an incident surface 502 and an output surface 503. The polarization conversion element 501 is manufactured through the above steps.

  According to the polarization conversion element of Embodiment 5 and the method for manufacturing the same, since the optical rotator 512 is formed on the first reflective film 513 by vapor deposition, there is no need to attach a resin film as in the prior art. No distortion of film (optical rotator), entrainment of bubbles, or misalignment. Therefore, the optical rotator 512 can be easily formed with high accuracy.

  In addition, as described above, the optical rotator 512 is configured to have a function of rotating the polarization axis (polarization plane) while maintaining linearly polarized light while light is transmitted twice. In addition, the film thickness is thinner than the optical rotators 112 and 212 of the polarization conversion elements 101 and 201 of the second embodiment. Therefore, since the film formation time of the optical rotator 512 that is a birefringent film can be shortened, a cheaper polarization separation element 501 can be realized.

  As described above, the polarization conversion elements according to the first to fifth embodiments have heat resistance and light resistance because inorganic materials, particularly metal oxides, are used as optical rotators. In the polarization conversion elements according to Embodiments 1 to 5, for example, tantalum oxide, niobium oxide, titanium oxide, zirconium oxide, and aluminum oxide may be used as the metal oxide that is the optical rotator.

  In addition, the film formed by oblique vapor deposition has a relatively low density, and if it is left in the atmosphere for a long period of time, moisture may enter and the characteristics may change. However, in the polarization conversion element according to the first to fifth embodiments, Since the optical rotator, which is a film formed by oblique vapor deposition, is sandwiched and confined between substrates, the characteristics are stable.

  Moreover, in the manufacturing method of the polarization conversion element concerning this Embodiment 1-5, since the optical rotator is formed by oblique vapor deposition, the optical rotator which has high birefringence can be formed easily. Therefore, a high-quality polarization conversion element can be easily manufactured.

  In addition, in the polarization conversion element according to the first to fifth embodiments, when the entrance surface and the exit surface are in contact with air, an antireflection film is formed on the surface to reflect at the time of entrance or exit. It may be prevented. Further, the polarization conversion element can be used by being bonded to an optical element such as a lens.

  The polarization conversion element and the method for manufacturing the polarization conversion element according to Embodiments 1 to 5 described above are merely examples, and are not limited thereto.

  The polarization conversion element of the present invention can be used for optical equipment using polarized light, and further includes a built-in optical rotator that does not deteriorate even when exposed to a high temperature environment or high brightness light. By using it, the lifetime and brightness of the projector can be improved.

Sectional drawing which shows the structure of the polarization converting element which concerns on Embodiment 1 of this invention. The figure explaining the vapor deposition apparatus for manufacturing the polarization conversion element concerning Embodiment 1 of this invention Sectional drawing which shows the arrangement | sequence at the time of adhesion | attachment in the manufacturing process of the polarization conversion element concerning Embodiment 1 of this invention Sectional drawing which shows the cutting position in the manufacturing process of the polarization conversion element concerning Embodiment 1 of this invention Sectional drawing which shows the structure of the polarization conversion element which concerns on Embodiment 2 of this invention. Sectional drawing which shows the arrangement | sequence at the time of adhesion | attachment in the manufacturing process of the polarization conversion element which concerns on Embodiment 2 of this invention. Sectional drawing which shows the cutting position in the manufacturing process of the polarization conversion element concerning Embodiment 2 of this invention Sectional drawing which shows the structure of the polarization conversion element which concerns on Embodiment 3 of this invention. Sectional drawing which shows the arrangement | sequence at the time of adhesion | attachment in the manufacturing process of the polarization conversion element which concerns on Embodiment 3 of this invention. Sectional drawing which shows the cutting position in the manufacturing process of the polarization conversion element concerning Embodiment 3 of this invention Sectional drawing which shows the structure of the polarization conversion element which concerns on Embodiment 4 of this invention. Sectional drawing which shows the arrangement | sequence at the time of adhesion | attachment in the manufacturing process of the polarization converting element which concerns on Embodiment 4 of this invention. Sectional drawing which shows the cutting position in the manufacturing process of the polarization converting element which concerns on Embodiment 4 of this invention. Sectional drawing which shows the structure of the polarization converting element which concerns on Embodiment 5 of this invention. Sectional drawing which shows the arrangement | sequence at the time of adhesion | attachment in the manufacturing process of the polarization converting element which concerns on Embodiment 5 of this invention. Sectional drawing which shows the cutting position in the manufacturing process of the polarization converting element which concerns on Embodiment 5 of this invention. Sectional drawing which shows the structure of the conventional 1st polarization conversion element The perspective view which shows the structure of the conventional 1st polarization conversion element. Sectional drawing which shows the structure of the conventional 2nd polarization conversion element

Explanation of symbols

101, 201, 301, 401, 501 Polarization conversion element 102, 202, 302, 402, 502 Incident surface 103, 203, 303, 403, 503 Emission surface 110, 310, 510 First laminated body 210, 410 Laminated body 111 , 211, 311, 411, 511 First transparent substrate 112, 212, 312, 412, 512 Optical rotator 120, 320, 520 Second laminate 121, 221, 321, 421, 521 Second transparent substrate 122, 213, 313, 413, 522 Polarization separation film 123, 214, 322, 414, 513 Reflective film 130, 330 Third transparent substrate 140, 240, 340, 440, 540 Adhesive 141, 241, 341, 441, 541 Cutting Line 151, 251, 351, 451, 551 Incident light 191 Vacuum evaporation system 92 Substrate holder 190 Chamber 193 Deposition source 601, 701 Polarization conversion element 602, 702 Incident surface 603, 703 Exit surface 604 First substrate 605 Second substrate 606, 706 Polarization separation film 607 Reflective film 608, 708 Adhesive layer 609 , 709 Optical rotator 610, 710 Incident light 704 Substrate 711 Antireflection film

Claims (10)

A plate-shaped polarization conversion element having an incident surface on which light is incident and an exit surface parallel to the incident surface,
A polarization separation film that separates incident light into S-polarized light and P-polarized light, transmits one of S-polarized light and P-polarized light, and reflects the other;
A film-like optical rotator made of an inorganic material that rotates the plane of polarization of light;
A reflective film that reflects light,
The polarization separation film, the optical rotator, and the reflection film are located between the incident surface and the exit surface, are inclined with respect to the entrance surface and the exit surface, and are periodically in a direction parallel to the entrance surface. A polarization conversion element arranged.   The polarization conversion element according to claim 1, wherein the optical rotator is a metal oxide film having birefringence.   The polarization conversion element according to claim 2, wherein the optical rotator is the metal oxide film having birefringence formed by oblique vapor deposition. A first laminate having a first transparent substrate and the optical rotator formed on one side of the first transparent substrate;
A second laminated body having a second transparent substrate, a polarization separation film formed on one surface of the second transparent substrate, and a reflective film formed on the other surface of the second transparent substrate. ,
The first stacked body and the second stacked body are inclined with respect to the incident surface and the exit surface, and are alternately stacked in a direction parallel to the incident surface and the exit surface,
The polarization conversion element according to claim 1, wherein the polarization separation film and the optical rotator face each other, and the reflection film and the first transparent substrate face each other. A laminate having a first transparent substrate, the polarization separation film and the optical rotator sequentially formed on one surface of the first transparent substrate, and the reflective film formed on the other surface of the first transparent substrate. Body,
A second transparent substrate,
The laminated body and the second transparent substrate are alternately stacked in a direction inclined with respect to the incident surface and the exit surface and parallel to the incident surface and the exit surface. The polarization conversion element according to claim 3. A first laminate having a first transparent substrate, the polarization separation film formed on one surface of the first transparent substrate, and the optical rotator formed on the other surface of the first transparent substrate; ,
A second laminate having a second transparent substrate and a reflective film formed on one side of the second transparent substrate;
The first laminate and the second laminate are inclined with respect to the incident surface and the exit surface, and are alternately laminated in a direction parallel to the entrance surface and the exit surface,
The polarization conversion element according to any one of claims 1 to 3, wherein the second transparent substrate and the polarization separation film face each other, and the optical rotator and the reflection film face each other. A laminate having a first transparent substrate, the polarization separation film formed on one surface of the first transparent substrate, and the optical rotator and the reflection film sequentially formed on the other surface of the first transparent substrate. Body,
A second transparent substrate,
The laminated body and the second transparent substrate are alternately stacked in a direction inclined with respect to the incident surface and the exit surface and parallel to the incident surface and the exit surface. The polarization conversion element according to claim 3. A first laminate having a first transparent substrate, and the reflective film and the optical rotator sequentially formed on one surface of the first transparent substrate;
A second laminated body having a second transparent substrate and a polarization separation film formed on one surface of the second transparent substrate;
The first laminate and the second laminate are inclined with respect to the incident surface and the exit surface, and are alternately laminated in a direction parallel to the entrance surface and the exit surface,
4. The polarization conversion element according to claim 1, wherein the first transparent substrate and the polarization separation film face each other, and the optical rotator and the second transparent substrate face each other. 5. A laminated body production step of producing a laminated body by forming an optical rotator as a metal oxide film by oblique vapor deposition on the first transparent substrate or a layer laminated on the first transparent substrate;
An adhesion step of alternately laminating and adhering the laminate produced in the laminate production step and the second transparent substrate; and
After the said adhesion process, the manufacturing method of a polarization conversion element provided with the cutting process which cut | disconnects the said adhesive body in the direction inclined with respect to the said laminated body and a said 2nd transparent substrate, and cuts out a plate-shaped body. A laminated body production step of producing a laminated body by forming an optical rotator as a metal oxide film by oblique vapor deposition on the first transparent substrate or a layer laminated on the first transparent substrate;
An adhesion step in which the first laminate produced in the laminate production step and the second laminate having at least a second transparent substrate are alternately laminated and bonded to form an adhesive;
A method of manufacturing a polarization conversion element, comprising: a cutting step of cutting the adhesive body in a direction inclined with respect to the first laminated body and the second laminated body and cutting out a plate-like body after the bonding step.

Images