JP2006234861A - Method of manufacturing optical glass, method of manufacturing polarization conversion element, and polarization conversion element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To utilize a reference face to perform an operation of division into a desired size or the like by surely keeping a portion to be the reference face up to the last stage of manufacturing procedure of an optical element. <P>SOLUTION: Optical glass plates 10, 11, and 12 are laminated like stairs having 45° in a longitudinal direction, and both right and left sides are formed into perpendicular faces to form a glass laminate block 13. Width of one or more optical glass plates 12 placed in a middle stage is narrowed to form reference grooves 14 running through in the longitudinal direction, in both right and left side parts, and the block is sliced so as to obtain the prescribed number of joined glass plane plates 15, and the joined glass plane plates 15 are subjected to edge treatment and surface polishing and then are cut in a state i which each joined glass plane plate 15 is accurately positioned in y and θ directions by disposing two positioning pins 22 provided in a positioning jig 23 for cutting, in the reference grooves 14 on both sides of the joined glass plane plate 15. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an optical element such as a polarization conversion element in which a total reflection film surface and a polarization film surface are alternately formed, and outputs the light with the polarization direction of incident light aligned, and a method for manufacturing the polarization conversion element. The present invention also relates to a polarization conversion element manufactured by the method for manufacturing the polarization conversion element.

  As an optical element, for example, a polarization conversion element exhibits a function of outputting the light with the polarization direction aligned without reducing the light use efficiency when light containing polarization components orthogonal to each other is incident. Is. For this reason, the optical element is formed in a flat plate shape, and the total reflection surface and the polarization surface are alternately formed in multiple stages at an angle of 45 ° with respect to the incident surface, A half-wave plate is formed in a stripe shape at a portion facing the polarization plane. As a result, when light including a P-polarized component and an S-polarized component is incident, the light of the S-polarized component is reflected by the polarization surface, then reflected again by the total reflection surface, and emitted as it is from the opposite surface. . On the other hand, the P-polarized component light is separated from the S-polarized component by transmitting through the polarization plane, and is emitted as S-polarized component light by rotating the polarization direction by 90 ° with a half-wave plate. . The configuration of this type of polarization conversion element is described in Patent Document 1, for example.

As described above, in order to arrange a total reflection surface and a polarization plane that are inclined at an angle of 45 ° with respect to the optical path so as to be alternately arranged in the vertical direction, an optical glass plate on which a total reflection film is formed, and a polarization The optical glass on which the films are formed are alternately overlapped and arranged so that their film surfaces are 45 ° with respect to the incident plane of the optical element. For this purpose, a glass wall block is formed by providing a reference wall inclined at 45 °, laminating two types of optical glass sequentially along the reference wall, and fixing each layer with an adhesive. To do. Then, this glass laminate block is sliced in a direction parallel to the reference wall with, for example, a wire saw, and both the front and back surfaces are polished to form a bonded glass flat plate having a predetermined thickness. If this bonded glass flat plate is arranged in the vertical direction, that is, if the polished surface is arranged in a direction perpendicular to the optical path, the total reflection surface and the polarization plane that are inclined at an angle of 45 ° with respect to the optical path will be in the vertical direction. Multiple arrays can be arranged alternately. The manufacture of such an optical element is disclosed in Patent Document 2. In Patent Document 2, the bonded glass flat plate obtained as described above is further divided to manufacture a beam splitter.
JP 10-186195 A JP 2000-199810 A

  By the way, after slicing the glass laminate block to have a predetermined thickness, both the front and back surfaces are polished. Since this polishing must be performed with high accuracy, it is generally performed by lapping. is there. In this lapping process, in order to protect the processing tool from being damaged, it is necessary to remove a sharp edge portion in advance on a corner portion or a ridge line of the workpiece. When this polishing process is performed, a reference position is lost in the outer shape of the workpiece. Then, after the workpiece is lapped, it is impossible to perform any processing by positioning the workpiece on the basis of the outer shape. Therefore, for example, in the stage of the bonded glass flat plate described above, it is a large format, and when this is cut and divided into a plurality of parts to produce an optical element of a predetermined size, there is no accurate reference, Inconveniences such as the possibility of variation in the dimensional accuracy of the product occur.

  The present invention has been made in view of the above points, and the object of the present invention is to reliably leave a portion serving as a reference surface until the final stage of manufacturing the optical element, It is intended to be able to perform operations such as dividing into a desired size extremely accurately.

  In order to achieve the above-described object, the present invention is to stack a plurality of optical glass plates having different optical characteristics in a step-like manner along a reference wall inclined at a predetermined angle. By combining, a glass plate blocking step for forming a glass laminate block that is inclined stepwise in the front-rear direction and the left and right sides are vertical, and the glass laminate block in a direction parallel to the reference wall A flat plate forming step of slicing each predetermined thickness to form a bonded glass flat plate, an edge processing step of removing edges by polishing ridge lines and corners of the bonded glass flat plate, and edge removal A surface polishing step for polishing both the front and back surfaces of the processed bonded glass flat plate, and a flat plate division for cutting the bonded glass flat plate subjected to the surface polishing into optical elements of a predetermined size. Of the optical glass plates to be bonded together in the glass plate blocking step, one or a plurality of optical glass plates laminated in an approximately middle stage are made shorter than other optical glass plates. By forming a reference groove on the left and right vertical surfaces formed in the glass laminate block, and when dividing the bonded glass flat plate in the flat plate dividing step, the positioning jig for cutting The reference portion is positioned by a positioning member provided on the head.

  In short, in the final stage of manufacturing the optical element, the large-sized bonded glass flat plate is divided into the necessary size as the optical element, thereby improving the manufacturing efficiency. A high quality optical element can be manufactured as a product by holding the reference portion until cutting for the division is performed.

  Two or more types of optical glass plates are alternately laminated, but one or a plurality of optical glass plates positioned at an intermediate stage may be formed of a thick unglazed glass plate. Thus, by inserting a raw glass plate in the middle, it is possible to divide the raw glass plate as a boundary portion in the plane plate dividing step. Further, the cut surfaces of the raw glass plates can be polished and the polished surfaces can be joined to each other.

  When the glass laminate block is formed, it is laminated in an inclined step shape having a predetermined angle, but a reference wall that is inclined at a minimum is required, but a second reference surface may be formed on the other side. it can. That is, in addition to the obliquely formed reference wall, a vertical second reference wall provided in a direction orthogonal to the reference wall is provided, and in the second reference wall, the reference groove is disposed in the arrangement portion of the reference groove. A protrusion is formed. In the glass plate blocking step, the optical glass plate is laminated along the reference wall and the second reference wall. For example, an ultraviolet curable resin can be used for bonding between the optical glass plates of the glass laminate block. And it sets so that an ultraviolet-ray may be irradiated from the end surface direction of optical glass.

  Here, the first invention when used as a method for manufacturing a polarization conversion element as an optical element includes: a first optical glass plate having a total reflection film formed along a reference wall having an inclination angle of 45 °; A glass that is inclined stepwise in the front-rear direction and the left and right sides are vertical by alternately arranging and laminating a plurality of step-like optical glass plates on which the polarizing film is formed. A glass plate blocking step for forming a laminated body block, and a flat plate forming step for slicing the glass laminated body block at a predetermined thickness in a direction parallel to the reference wall to form a bonded glass flat plate, An edge processing step for polishing edges and corners of the bonded glass flat plate to remove edges, a surface polishing step for polishing both front and back surfaces of the bonded glass flat plate subjected to the edge removal processing, and the bonding glass flat A flat plate dividing step of cutting the plate into optical elements of a predetermined size, and a half wavelength at a position facing the polarizing film or the total reflection film on one side of the flat plate thus divided Among the optical glass plates to be laminated in the glass plate blocking step, one or a plurality of optical glass plates laminated in an approximately middle stage are shorter than other optical glass plates. By forming a reference groove on the right and left vertical surfaces formed in the glass laminate block by making the size, and dividing the bonded glass plane plate in the plane plate dividing step, It is characterized in that the reference portion is positioned by a positioning member provided in the cutting positioning jig.

  In addition, as a second invention regarding the method for manufacturing a polarization conversion element, a first optical glass plate having a total reflection film formed along a reference wall having an inclination angle of 45 °, and a first film having a polarization film formed thereon The two optical glass plates are alternately arranged and laminated in a stepped manner, and the optical glass plate disposed in the middle step is composed of a thicker glass plate than the other optical glass plates. A glass plate blocking step for forming a glass laminate block that is inclined stepwise in the front-rear direction and the left and right sides are vertical, and the glass laminate block is arranged in a direction parallel to the reference wall. A flat plate forming step for slicing each thickness to form a bonded glass flat plate, an edge processing step for removing edges by polishing ridges and corners of the bonded glass flat plate, and an edge removing process Table of bonded glass flat plate made A surface polishing step of polishing both surfaces, a plane plate dividing step of cutting the bonded glass plane plate to be divided into optical elements of a predetermined size, and cutting at a portion of the base glass plate to divide into two. Then, a laminating step of laminating a half-wave plate at a position facing the polarizing film or the total reflection film on one side surface of the flat plate thus divided, and the cut surface divided into two by the raw glass plate were polished. Later, it comprises an inversion joining step in which one side is inverted to join the polished surfaces, and one or more of the optical glass plates laminated in the glass plate blocking step are laminated in an approximately middle stage By making the optical glass plate shorter than other optical glass plates, reference grooves are formed on the left and right vertical surfaces formed in the glass laminate block, and the reference grooves are formed at the time of the plane plate dividing step. Bonded glass When the flat plate is divided, the reference plate is positioned by a positioning member provided in the cutting positioning jig.

  Since the reference plane remains until the final stage of manufacturing the optical element, high-precision processing and processing are performed until the bonded glass flat plate is divided, and an effect of obtaining high quality as an optical element is obtained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. First, FIG. 1 shows a configuration of an optical element as a final product manufactured by the method of the present invention. This optical element is a polarization conversion element and two structurally different elements are shown. FIG. 2A shows an optical element 1A having an incident surface 2A and an exit surface 3A, and an optical film is formed at an angle of 45 ° with respect to the entrance surface 2A and the exit surface 3A. The optical film is a total reflection film 4, and the second optical film is a polarizing film 5. The polarizing film 5 reflects S-polarized light and transmits P-polarized light. Further, on the exit surface 3A side of the optical element 1A, a half-wave plate 6 is formed by a film forming means at a portion facing the polarizing film 5.

  The light emitted from the light source 7 includes S-polarized light and P-polarized light. The emitted light from the light source 7 is included in the incident light from the incident surface 2A while passing through the optical element 1. The S-polarized light is reflected by the polarizing film 5, and the reflected light is reflected again by the total reflection film 4 and then emitted as S-polarized light from the exit surface 3 </ b> A. On the other hand, the P-polarized light is separated from the S-polarized light by the polarizing film 5, and the plane of polarization is rotated by 90 ° by the half-wave plate 6 to be converted into S-polarized light. Accordingly, all light is converted into S-polarized light on the exit side of the optical element 1A. In the illustrated polarization conversion element, light including S-polarized light and P-polarized light is converted into S-polarized light and emitted. However, the half-wave plate 6 faces the total reflection film 4. In this case, all the emitted light becomes P-polarized light.

  FIG. 1B shows another type of optical element 1B, where the 2B side is the entrance surface and the 3B side is the exit surface. In this optical element 1B, total reflection films 4 and polarizing films 5 are alternately formed, but the tilt directions of the films are reversed on both the left and right sides with the central portion C in the length direction as the center. The half-wave plate 6 is provided on the side facing the polarizing film 5. Even in this configuration, the light emitted from the light source 7 including the P-polarized light and the S-polarized light is all emitted as S-polarized light in the same manner as the optical element 1A.

  Therefore, in the following, a method for manufacturing the optical element 1B as a polarization conversion element will be described. Here, as shown in FIGS. 2 and 3, three types of optical glass plates 10, 11, and 12 are used. The optical glass plate 10 has a total reflection film 4 formed on one surface thereof, and the optical glass plate 11 has a polarizing film 5 formed on one surface thereof. Moreover, the optical glass plate 12 is a raw glass which is not formed on any surface. One or a plurality of optical glass plates 12 are used. On the other hand, the optical glass plates 10 and 11 have the same thickness and the same size. On the other hand, the optical glass plate 12 is thicker than the optical glass plates 10 and 11, and the width dimension is smaller than them.

  The optical glass plates 10 and 11 are laminated alternately. And the optical glass plate 12 is interposed about 1 step | paragraph of the center, or 2-3 steps | paragraphs. An optical glass plate 11 on which a polarizing film 5 is formed is disposed on the upper and lower stages of the stage on which the optical glass plate 12 is disposed, and an optical film on which a total reflection film 4 is formed on the lowermost and uppermost stages. A glass plate 10 is disposed. By laminating the optical glasses 10, 11 and 12 in this order, the glass laminate block 13 is formed.

  This glass laminate block 13 is laminated stepwise, and as a whole, as shown in FIG. 2, the glass laminate block 13 has a stepped shape with an angle of 45 ° in the front-rear direction, as shown in FIG. The left and right sides of the glass laminate block 13 are vertical surfaces. For this, two reference walls are used. The first reference wall 20 serves as an inclined reference wall for forming the staircase of the glass laminate block 13, and the first reference wall 20 is inclined at 45 °. The second reference wall 21 is in a vertical state, and a protrusion 21a is formed in the middle. The optical glass 12 is laminated at the position of the protrusion 21a, and the length of the protruding portion of the protrusion 21a is half of the dimensional difference in the width direction between the optical glass plates 10 and 11 and the optical glass plate 12. The dimensions correspond to.

  The optical glass plates 10, 11 and 12 can be easily and accurately laminated by bringing the two adjacent sides into contact with the first and second reference walls 20 and 21 thus formed. Can be laminated. When a predetermined number of optical glass plates are laminated, a glass laminate block 13 is formed. As shown in FIG. 2, the glass laminate block 13 is laminated in an inclined state while being shifted in an oblique direction, but the left and right side portions are generally in a vertical state. As is clear from FIG. 3, in the portion of the optical glass plate 12 positioned in the middle stage, grooves 14 penetrating in the front-rear direction are formed on both left and right side portions. Here, all of the optical glass plates 10 to 12 are strictly controlled in size, and therefore the groove 14 formed between the glasses serves as a reference groove having a highly accurate dimension.

  When an optical glass plate is laminated to form the glass laminate block 13, for example, an ultraviolet curable adhesive is applied to the laminated surface, and after the lamination is finished, for example, ultraviolet rays are irradiated from the vertical surface side. By doing so, the ultraviolet curing adhesive is cured. Thereby, the glass laminated body block 13 is fixed. The above is the glass plate blocking step.

  Next, as shown in FIG. 4, the glass laminate block 13 is sliced in the inclined direction, that is, in the direction parallel to the first reference wall 20, to obtain the bonded glass flat plate 15. As will be described later, the thickness T of the bonded glass flat plate 15 is thicker than the final thickness of the optical element 1B by the amount of polishing on both sides. In order to slice this glass laminated body block 13, it can cut | disconnect easily by using a wire saw or a band saw. Of course, the glass laminate block 13 is cut after being taken out from the reference wall. This step is a flat plate forming step. Here, the reference groove 14 exists in all of the predetermined number of bonded glass flat plates 15 obtained by slicing the glass laminate block 13.

  Since the bonded glass flat plate 15 formed in the flat plate forming step has sharp portions at its ridgeline portions, that is, each side constituting the six surfaces and corner portions, these sharp portions are polished. Then chamfer. This is the edge processing step. This edge treatment process is to prevent damage to parts of the polishing apparatus, particularly a lapping surface plate, and the like, and to prevent cracking and chipping of the bonded glass flat plate 15 in the surface polishing process described later. However, although a sharp part remains in the part of the reference groove 14, the reference groove 14 is a deep position and has a slight length, so that the processing tool is damaged at the time of lapping. And so on.

  The surface of the bonded glass flat plate 15 obtained as described above is polished. In this surface polishing, for example, both front and back surfaces are simultaneously processed by lapping. This surface polishing is performed for the amount remaining as a polishing allowance in the flat plate forming step.

  After that, as shown in FIG. 5, the bonded glass flat plate 15 after film formation is placed on a cutting positioning jig 23 in which two positioning pins 22 are erected, for example, a diamond cutter or the like. The bonded glass flat plate 15 is cut along cutting lines DX1 to DX3 and DY1 to DY4 by a cutting tool. Then, after cutting, the width G is polished for each cutting line. The polishing for the width G is indispensable at least at the position of the cutting line DX2, but it is not always necessary to polish at other positions. Here, of the cutting lines DX1 to DX3 in the horizontal direction, the cutting by the cutting lines DX1 and DX3, when configured as the polarization conversion element 1B, creates flat portions at both the upper and lower ends, and the intermediate cutting line DX2 Is a cutting line for performing reverse joining as will be described later.

  When the bonded glass flat plate 15 is cut, the bonded glass flat plate 15 must be accurately positioned on the cutting positioning jig 23. Here, in the positioning of the bonded glass flat plate 15, it is necessary to accurately position the y direction and the θ direction among the x, y, and θ directions. However, in the x direction, although the interval between the cutting lines DY1-DY2, DY2-DY3, and DY3-DY4 is important, it does not matter at all if these cutting lines are slightly shifted from side to side. From the above, exceptional positioning accuracy is not required in this direction. In the positioning jig 23 for cutting, two positioning pins 22 and 22 are erected, and these positioning pins 22 are in the reference grooves 14 located on both the left and right sides of the bonding glass plane plate 15. The side wall portion of the reference groove 14 is a side surface portion of the optical glass plate 11 having accurate dimensional accuracy, and this portion is not polished during the edge processing step, so that dimensional accuracy is maintained. Accordingly, by bringing the two positioning pins 22 into contact with the side surfaces of the optical glass plate 11 in the reference grooves 14 on both sides, the bonded glass flat plate 15 can be accurately positioned in the y direction and the θ direction. . Further, even if the side surface of the optical glass plate 10 is partially chipped, the contact portion with the positioning pin 22 is avoided from the chipped position by shifting the bonding glass flat plate 15 in the x direction. In this way, positioning can be performed.

  The above is the plane plate dividing step. In this plane plate dividing step, the portions on the left side from the cutting line DY1 and the right side from the cutting line DY4 in FIG. 5 are discarded, and as a result, there is no reference groove. However, since no positioning wall is required thereafter, there is no problem even if the positioning reference position does not exist.

  When the optical element 1B is divided into six parts as described above, it is limited to a surface on the emission surface 3B side that faces the polarizing film 5 or a position that faces the total reflection film 4. Thus, the half-wave plate 6 is formed. The half-wave plate 6 can be formed by a film forming means, or an appropriate means such as a film attachment can be employed. Accordingly, on the surface on the exit surface 3B side, the surface from which the glass is exposed and the surface on which the half-wave plate 6 is laminated are alternately striped. After this lamination, an antireflection film is formed on both the front and back surfaces.

  Further, as shown in FIG. 6, one of the optical element pieces 16a and 16b, which is divided into two by the cutting line DX2 and whose end face is polished, for example, the optical element piece 16b is inverted and turned face down. Then, the surfaces of the ground glass plate 12 are bonded and fixed with an adhesive. Thereby, the optical element 1B shown in FIG. 1B is manufactured. Here, in the optical element 1B, when the half-wave plate 6 is laminated at a position facing the polarizing film 5, the emitted light becomes S-polarized light, and the half-wave plate is located at a position facing the total reflection film 4. When 6 is arranged, the emitted light becomes P-polarized light.

  In the case of manufacturing the optical element 1A shown in FIG. 1A, the optical glass plate constituting the middle stage of the glass laminate block is not an elemental glass plate, but is an optical glass. The plates 10 and 11 are stacked alternately. Then, in order to form the reference groove, except for the lowermost and uppermost optical glass plates, one or a plurality of optical glass plates laminated in the middle are used with a narrowed width dimension. . Further, in the plane plate dividing step, it is not necessary to cut a portion corresponding to the cutting line DX2 in FIG. 6, and subsequent reverse joining is not performed.

It is a structure explanatory drawing of the polarization conversion element as an optical element. It is explanatory drawing which shows the process of forming a glass laminated body block in the method of this invention. FIG. 3 is a side view of FIG. 2. In the method of this invention, it is explanatory drawing which shows a plane plate formation process. In the method of this invention, it is explanatory drawing which shows a plane plate division | segmentation process. In the method of this invention, it is explanatory drawing which shows the inversion joining process.

Explanation of symbols

1A, 1B Optical elements 10, 11, 12 Optical glass plate 13 Glass laminate block 14 Reference groove 15 Bonded glass plane plates 16a, 16b Optical element piece 20 First reference wall 21 Second reference wall 21a Projection 22 Positioning Pin 23 Positioning jig for cutting

Claims (6)

Along the reference wall inclined at a predetermined angle, by laminating a plurality of optical glass plates having different optical characteristics in a stepped manner according to a certain order, they are inclined stepwise in the front-rear direction, A glass plate blocking step for forming a glass laminate block in which the left and right sides are vertical;
A flat plate forming step of slicing the glass laminate block at a predetermined thickness in a direction parallel to the reference wall to form a bonded glass flat plate,
An edge processing step of polishing edges and corners of the bonded glass flat plate to remove edges,
A surface polishing step for polishing both the front and back surfaces of the bonded glass plane plate that has been subjected to the edge removal treatment,
It consists of a plane plate dividing step of cutting the bonded glass plane plate that has undergone surface polishing and dividing it so as to be an optical element of a predetermined size,
Of the optical glass plates to be bonded together in the glass plate blocking step, one or a plurality of optical glass plates laminated in an approximately middle stage are made shorter than the other optical glass plates, thereby making a glass laminate. Positioning members provided in the positioning jig for cutting when forming the reference grooves on the vertical surfaces on the left and right sides formed in the block, and dividing the reference glass into the bonded glass flat plate in the flat plate dividing step A method for manufacturing an optical element, characterized in that the optical element is used as a reference portion positioned by the above-described method. When forming the glass laminate block, one or a plurality of optical glass plates disposed in an intermediate stage are formed of a raw glass plate thicker than other optical glass plates, and the width of the raw glass plate The reference groove is formed by shortening the dimensions, and in the flat plate dividing step, the raw glass plate is cut into two parts by cutting, and after the cut surface is polished, one of them is inverted and then the polished surface The method of manufacturing an optical element according to claim 1, wherein: When forming the glass laminate block, in addition to the inclined reference wall, a second reference wall in a vertical state provided in a direction perpendicular to the reference wall is provided, and the second reference wall A protrusion is formed in the reference groove arrangement portion, and the optical glass plate is laminated along the reference wall and the second reference wall in the glass plate blocking step. Item 2. A method for producing an optical element according to Item 1. A plurality of first optical glass plates on which total reflection films are formed and second optical glass plates on which polarizing films are formed are arranged alternately along a reference wall having an inclination angle of 45 °. By laminating and laminating, a glass plate blocking step for forming a glass laminate block that is inclined stepwise in the front-rear direction and the left and right sides are vertical;
A flat plate forming step of slicing the glass laminate block at a predetermined thickness in a direction parallel to the reference wall to form a bonded glass flat plate;
An edge processing step of polishing edges and corners of the bonded glass flat plate to remove edges,
A surface polishing step for polishing both the front and back surfaces of the bonded glass plane plate that has been subjected to the edge removal treatment,
A plane plate dividing step of cutting the bonded glass plane plate and dividing it so as to be an optical element of a predetermined size,
A laminating step of laminating a half-wave plate at a position facing the polarizing film or the total reflection film on one side surface of the divided flat plate,
Of the optical glass plates to be bonded together in the glass plate blocking step, one or a plurality of optical glass plates laminated in an approximately middle stage are made shorter than the other optical glass plates, thereby making a glass laminate. Positioning members provided in the positioning jig for cutting when forming the reference grooves on the vertical surfaces on the left and right sides formed in the block, and dividing the reference glass into the bonded glass flat plate in the flat plate dividing step A method for manufacturing a polarization conversion element, characterized in that the reference part is positioned by the above-described method. A plurality of first optical glass plates on which total reflection films are formed and second optical glass plates on which polarizing films are formed are arranged alternately along a reference wall having an inclination angle of 45 °. Laminated and bonded together, and the optical glass plate arranged in the middle step is composed of a thicker glass plate than the other optical glass plates, tilted stepwise in the front-rear direction, and the left and right sides are vertical A glass plate blocking step for forming a glass laminate block,
A flat plate forming step of slicing the glass laminate block at a predetermined thickness in a direction parallel to the reference wall to form a bonded glass flat plate;
An edge processing step of polishing edges and corners of the bonded glass flat plate to remove edges,
A surface polishing step for polishing both the front and back surfaces of the bonded glass plane plate that has been subjected to the edge removal treatment,
A flat plate dividing step of cutting the bonded glass flat plate and dividing it into optical elements of a predetermined size, and then cutting into two parts by cutting at the portion of the raw glass plate,
A lamination step of laminating a half-wave plate at a position facing the polarizing film or the total reflection film on one side of the divided flat plate;
After polishing the cut surface divided into two by the raw glass plate, it comprises an inversion joining step of reversing one and joining the polished surfaces,
Of the optical glass plates to be bonded together in the glass plate blocking step, one or a plurality of optical glass plates laminated in an approximately middle stage are made shorter than the other optical glass plates, thereby making a glass laminate. Positioning members provided in the positioning jig for cutting when forming the reference grooves on the vertical surfaces on the left and right sides formed in the block, and dividing the reference glass into the bonded glass flat plate in the flat plate dividing step A method for manufacturing a polarization conversion element, characterized in that the reference part is positioned by the above-described method. The polarization conversion element manufactured by Claim 4 or Claim 5.

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