JPH1184112A - Color synthesis prism and its production as well as projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To embody a color synthesis prism which is capable of improving the flatness of two kinds of multilayered dichroic films and is easy to work as a color synthesis means used for a projection type display device. SOLUTION: A first coupled body is formed by depositing first multilayered optical films 112 by evaporation on one surface of plural transparent flat plates and stacking and joining these plates. Next, the first coupled bodies are cut square to the joint surfaces, by which the second coupled bodies are formed. The second coupled bodies are so polished as to have the same thickness as the thickness of the transparent flat plates and the second multilayered optical films 122 are deposited by evaporation on the one cut surface thereof. The fourth coupled bodies are obtd. by adhering these bodies. The coupled bodies are further cut at an angle of 45 deg. and the cut surfaces are parallel polished by which the sixth coupled bodies are formed. Further, the sixth coupled bodies are cut to a prescribed size and are finished to the color synthesis prism 160 of a quadrangular prism shape.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color synthesizing prism for synthesizing three primary colors of red, green and blue into one light, a method of manufacturing the same, and a color image projected using the color synthesizing prism and a light valve. And a projection display device.

[0002]

2. Description of the Related Art In order to obtain a large-screen image, an optical image corresponding to an image signal is formed on a light valve, the light valve is irradiated with light, and the image light is enlarged and projected on a screen by a projection lens. Display device. Recently, a projection type display device using a liquid crystal panel as a light valve has attracted attention. In particular, a projection type display device utilizing a phenomenon in which the optical rotation of a twisted nematic (TN) liquid crystal is changed by an electric field has been commercialized.

In this type of projection display device, a liquid crystal panel for red, green, and blue is used to increase the light output and resolution, and a single projection lens is used to simplify the operation. It has become mainstream. In this method, a color combining prism is used to combine three primary color lights into one light.

FIG. 16 shows the structure of this color combining prism. The color combining prism 80 includes the first to fourth right-angle prisms 8.
3, 84, 85, 86. Right angle prism 83
A red reflection dichroic multilayer film 81 is formed on one surface of the right angle prism 84 and one surface of the right angle prism 84. A blue reflection dichroic multilayer film 82 is formed on one surface of the right-angle prism 83 and the other surface of the right-angle prism 86 that sandwiches the right angle. Thus, the red reflection dichroic multilayer film 81 and the blue reflection dichroic multilayer film 82
Are referred to herein as optical multilayer films. The four rectangular prisms 83 to 86 are joined so that these optical multilayer films have an X-shape to form a rectangular parallelepiped color synthesis prism.

Each of the red-reflective dichroic multilayer film 81 and the blue-reflective dichroic multilayer film 82 is formed by alternately laminating high-refractive-index films and low-refractive-index films. The red-reflective dichroic multilayer film 81 reflects red light. To transmit green light and blue light. The blue reflection dichroic multilayer film 82 reflects blue light and transmits red light and green light.

[0006]

In the color combining prism shown in FIG. 16, the two red-reflective dichroic multilayer films 81 and the two blue-reflective dichroic multilayer films 82 need to be joined so as to be completely on the same plane. There is.
If not, double images may appear in the projected image or 3
This causes a problem that color pixels do not overlap.

As a method for accurately bonding the prisms, the height (length in the W-axis direction) of the first right-angle prism 83 is made longer than that of the second right-angle prism 84, and the height of the fourth right-angle prism 86 is reduced. The length is made longer than the third right-angle prism 85. Then, the first right-angle prism 83 and the second right-angle prism 83 are formed so that rectangular exposed planes are formed on both sides (+ W and -W directions).
And the third right-angle prism 8
5 and the fourth right-angle prism 86 are joined. Then, a method of bonding two bonded prisms so that the exposed planes on both sides are the same plane has been proposed (see, for example, JP-A-3-138603 and JP-A-8-184798). However, in this method, it is necessary to strictly secure the right angles of the right angles of the four right angle prisms.
There is a problem in that the processing method of the right-angle prism becomes complicated, and the cost increases accordingly.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems. In a color synthesizing prism in which two types of dichroic multilayer films are crossed in an X-shape, the planes of these dichroic multilayer films are provided. It is a first object of the present invention to realize a color synthesizing prism capable of improving the degree and to realize a manufacturing method for manufacturing a color synthesizing prism having such characteristics at low cost. It is a second object of the present invention to provide a projection display device that projects a color image using the color combining prism.

[0009]

In order to solve such a problem, the invention according to claim 1 of the present application is directed to a case in which the thickness direction of the transparent substrate having the refractive index n is set to the z direction, and (x) perpendicular to the z direction. , Y) a first step of polishing two opposing flat surfaces parallel and having a predetermined thickness t when a plane parallel to the plane is defined as a flat surface of the transparent substrate, to obtain a plurality of transparent flat plates; A second step of forming a first optical multilayer film having a first spectral transmittance characteristic on one of the polished surfaces of the transparent flat plate obtained in the first step; Using a plurality of transparent flat plates, the first optical multilayer film is laminated in the z-direction so as to be sandwiched therebetween, and bonded using a transparent adhesive to form a first rectangular parallelepiped combined body. And cutting the first bonded body into a plurality of pieces at a cut surface perpendicular to the bonding surface of the third step. A fourth step of polishing the cut surface to form a second combined body having a thickness in the x-direction of t, and one of the polished surfaces parallel to the (y, z) plane of the second combined body, A fifth step of forming a second optical multilayer film having a second spectral transmittance characteristic and forming a third combined body; and forming a plurality of the third optical multilayer films so as to sandwich the second optical multilayer film. Are laminated along the x direction, and the end faces of the third composite are aligned so that the first optical multilayer film forms the same plane parallel to the (x, y) plane. A sixth step of forming a rectangular parallelepiped fourth bonded body by joining the first optical multilayer film and the second optical multilayer film through an intersection line between the first optical multilayer film and the second optical multilayer film. The fourth combined body is cut along a cutting plane parallel to the y-axis so as to be at 45 ° with respect to the optical multilayer film of No. 2, and a fifth polygonal prism-shaped end face having a trapezoidal shape is obtained. A seventh step of forming a united body, and when the fifth combined body is cut at a cutting plane orthogonal to the cutting plane of the seventh step, the first and second optical multilayer films are orthogonal diagonal lines at end faces. An eighth step in which the cutting position is determined so as to form a square prism-shaped sixth combined body having a square end surface by the cutting process, and a step parallel to the y-axis of the sixth combined body. A ninth step of obtaining a color combining prism by polishing each cut surface.

According to a second aspect of the present invention, the thickness direction of the transparent substrate having the refractive index n is defined as the z direction, and a plane parallel to a (x, y) plane perpendicular to the z direction is defined as a flat surface of the transparent substrate. A first step of polishing two opposing flat plate surfaces so as to be parallel and have a predetermined thickness t to obtain a plurality of transparent flat plates, and one polishing surface of the transparent flat plate obtained in the first step A second step of forming a first optical multilayer film having a first spectral transmittance characteristic, and using the plurality of transparent flat plates obtained in the second step, the first optical multilayer film Are laminated in the z-direction so as to be sandwiched therebetween, and joined using a transparent adhesive to form a first rectangular parallelepiped combined body; and a cut surface perpendicular to the joint surface in the third step. The first joint is cut into a plurality of pieces, and the cut surface is polished to obtain a second joint having a thickness in the x direction of t. Forming a second optical multilayer film having a second spectral transmittance characteristic on one of the polished surfaces parallel to the (y, z) plane of the second combined body. A fifth step of forming a third combined body; and laminating a plurality of the third combined bodies along the x-direction so that the second optical multilayer film is sandwiched therebetween; The end faces of the third combined body are aligned so that the multilayer film forms the same plane parallel to the (x, y) plane, and the third combined body is joined using a transparent adhesive to form a fourth rectangular parallelepiped combined body. Step 6, passing through the vicinity of the line of intersection between the first optical multilayer film and the second optical multilayer film, and applying 45% to the first and second optical multilayer films.
A seventh step of cutting the fourth combined body along a cutting plane parallel to the y-axis so as to form a fifth combined body having a polygonal prism shape having a trapezoidal end surface; An eighth step of cutting the fifth joint body at a cutting plane orthogonal to the cutting plane of the step, and forming a square prism-shaped sixth joint body whose end face is square or rectangular by the cutting process; A ninth step of obtaining a color combining prism by polishing each cut surface parallel to the y-axis of the sixth combined body.

According to a third aspect of the present invention, in the method of manufacturing a color synthesizing prism according to the first or second aspect, the sixth combined body formed in the ninth step is replaced with the first and second combined bodies. It is characterized in that the optical multilayer film is cut into predetermined length units on a cut surface perpendicular to the optical multilayer film.

According to a fourth aspect of the present invention, in the method of manufacturing a color synthesizing prism according to the first or second aspect, the thickness tolerance in the z direction of each of the transparent flat plates manufactured in the first step is equal to or less than the first thickness. The thickness is not more than 100 times the thickness of the first or second optical multilayer film.

According to a fifth aspect of the present invention, in the method of manufacturing a color synthesizing prism according to the first or second aspect, the tolerance of the thickness in the x direction of each of the second combined bodies manufactured in the fourth step is as follows. The thickness is not more than 100 times the thickness of the first or second optical multilayer film.

According to a sixth aspect of the present invention, in the method for manufacturing a color combining prism according to the first or second aspect, in the sixth step, one of the third combined bodies parallel to the (x, y) plane is formed. Are bonded to each other so that the end faces thereof are flush with each other.

According to a seventh aspect of the present invention, in the method of manufacturing a color synthesizing prism according to the first or second aspect, the arrangement order and the direction of the plurality of second combined bodies manufactured in the fourth step are arranged. In the sixth step, the third conjugate is arranged and joined using the identification code in the sixth step so as to have the same cutting order as the second conjugate. Things.

According to an eighth aspect of the present invention, in the method of manufacturing a color synthesizing prism according to the first aspect, the first and second transparent substrates having different lengths in the y direction in the first step.
Using the types, a first transparent flat plate whose length in the y direction is w and a second transparent flat plate whose length in the y direction is shorter than w are created,
In the step of (1), the first transparent flat plate and the second transparent flat plate are alternately laminated such that both end surfaces parallel to the (y, z) plane are respectively the same plane, and (x, z) is bonded by bonding the laminated surfaces. )
A first combined body having a step formed on an end surface parallel to the surface is formed.

According to a ninth aspect of the present invention, when the thickness direction of the transparent substrate having the refractive index n is z, and the flat surface thereof is the (x, y) plane, the two opposing (x, y) planes are A first step of polishing the transparent substrate so as to be parallel and having a predetermined thickness t to obtain a plurality of transparent flat plates, and a first spectral transmission on one of the polished surfaces of the transparent flat plates obtained in the first step. A second step of forming a first optical multilayer film having a ratio characteristic, and a plurality of transparent flat plates with the optical multilayer film obtained in the second step, wherein the first optical multilayer film is sandwiched. A third step of laminating in the z-direction and joining using a transparent adhesive to form a first rectangular parallelepiped combined body, and a cut surface perpendicular to the joint surface of the third step, The first combined body is cut into a plurality of pieces, and the cut surface is polished to form a second combined body having a thickness t in the x direction. Step 4 and forming a second optical multilayer film having a second spectral transmittance characteristic on one of the polished surfaces (y, z) of the second combined body to form a third combined body. Fifth step, a plurality of the third combined bodies are stacked in the x direction so that the second optical multilayer film is sandwiched, and the first optical multilayer film is on the same plane (x, y). A sixth step of aligning the end faces of the third combined body to form a fourth combined body using a transparent adhesive to form a fourth combined body having a rectangular parallelepiped shape; Passing through the line of intersection with the second optical multilayer,
The fourth bonded body is cut at a cut surface along the y direction so as to be 5 °, and the cut surface is ground and polished to form a polygonal column-shaped fifth bonded body having a trapezoidal end surface shape. A seventh step, and cutting the fifth combined body at a cutting plane along the y-direction orthogonal to the cutting plane in the seventh step, and forming the first and second optics at an (x, z) end face. An eighth step of forming a quadrangular prism-shaped sixth combined body in which the multilayer film has an orthogonal diagonal line and a square end face shape, and y of the sixth combined body
And a ninth step of obtaining a color combining prism by polishing an unpolished surface among the cut surfaces along the direction.

According to a tenth aspect of the present invention, the thickness direction of the transparent substrate having the refractive index n is z, and the plane of the transparent substrate is (x, y).
When a flat surface is used, the transparent substrate is polished so that two opposing (x, y) planes are parallel and have a predetermined thickness t to obtain a plurality of transparent flat plates. A second step of forming a first optical multilayer film having a first spectral transmittance characteristic on one of the polished surfaces of the obtained transparent flat plate, and a transparent film with the optical multilayer film obtained in the second step. Using a plurality of flat plates, z is set so that the first optical multilayer film is interposed therebetween.
A third step of forming a first rectangular parallelepiped joined body by laminating in the direction and joining the first combined body using a transparent adhesive, and a cutting surface perpendicular to a joining surface of the third step, The combined body is cut into a plurality of pieces, and the cut surface is polished to obtain a second piece having a thickness t in the x direction.
Forming a second optical multilayer film having a second spectral transmittance characteristic on one of the polished surfaces (y, z) of the second composite body; A fifth step of forming the combined body of No. 3; and laminating a plurality of the third combined bodies in the x-direction so that the second optical multilayer film is interposed therebetween. A sixth step of aligning the end faces of the third combined body so as to form the same plane (x, y) and joining them with a transparent adhesive to form a fourth rectangular parallelepiped combined body; The cross section along the y direction passes through the vicinity of the line of intersection between the first optical multilayer film and the second optical multilayer film and is at 45 ° with respect to the first and second optical multilayer films. A seventh step of cutting the fourth combined body, grinding and polishing the cut surface to form a polygonal column-shaped fifth combined body having a trapezoidal end face; The fifth connecting body is cut along a cutting plane along the y-direction orthogonal to the cutting plane in the seventh step, and a sixth connecting body in the form of a quadrangular prism whose end surface shape is square or rectangular is formed. 8; and a ninth step of obtaining a color combining prism by polishing an unpolished surface among the respective cut surfaces along the y direction of the sixth combined body. is there.

According to a twelfth aspect of the present invention, in the method of the ninth or tenth aspect, the ninth aspect is provided.
Is characterized in that the sixth combined body prepared in the step is cut in units of a predetermined length in the y-direction.

According to a twelfth aspect of the present invention, in the method for manufacturing a color synthesizing prism according to the ninth or tenth aspect, the first method is provided.
The tolerance of the thickness in the z-direction of each transparent flat plate manufactured in the step is 100 times or less the thickness of the first or second optical multilayer film.

According to a thirteenth aspect of the present invention, in the method for manufacturing a color synthesizing prism according to the ninth or tenth aspect, the fourth aspect is provided.
The tolerance of the thickness in the x direction of each of the second combined bodies manufactured in the step is 10% of the thickness of the first or second optical multilayer film.
It is characterized by being less than 0 times.

According to a fourteenth aspect of the present invention, in the method of manufacturing a color synthesizing prism according to the ninth or tenth aspect, the sixth aspect is provided.
In the step, the third joint is bonded so that one end face of the third joint parallel to the (x, y) plane is on the same plane.

According to a fifteenth aspect of the present invention, in the method of manufacturing a color synthesizing prism according to the ninth or tenth aspect, there is provided a method of manufacturing a color synthesizing prism, comprising
Attaching identification codes indicating the arrangement order and direction to the plurality of second combined bodies manufactured in the step, and using the identification codes in the sixth step, the cutting order of the second combined bodies and The third conjugates are arranged and joined so as to be identical.

According to a sixteenth aspect of the present invention, in the method of manufacturing a color synthesizing prism according to the ninth aspect, in the first step, the first and second transparent substrates having different lengths in the y direction are provided.
Using a type, a first transparent flat plate having a long length in the y direction and a second transparent flat plate having a short length in the y direction are formed. In a third step, both end faces of (y, z) are in the same plane. The first transparent flat plate and the second transparent flat plate are alternately laminated so as to obtain a first combined body having a step formed on the (x, z) plane by bonding the laminated surfaces. It is assumed that.

[0025] The invention according to claim 17 is the invention according to claims 1 to
According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device.

[0026] The invention according to claim 18 is a light source which emits light including three primary colors of red, green and blue, and decomposes the light emitted from the light source into three primary colors of red, green and blue. A color separation unit; R, G, and B light valves, each of which receives primary color light emitted from the color separation unit and forms an optical image of three primary colors according to an input video signal; A color combining means for combining light emitted from the light valve with image light having one optical axis, and a projection lens for entering the light emitted from the color combining means and projecting the image light on a screen. , Wherein the color synthesizing means is configured to output a color image.
6 is a color combining prism produced by any one of the manufacturing methods described above.

The invention according to claim 19 is the invention according to claim 18.
Wherein the R, G, and B light valves are transmissive liquid crystal panels.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 A method for manufacturing a color combining prism according to Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 4 are perspective views showing steps in a method for manufacturing a color combining prism according to the first embodiment.

Here, coordinates are defined to make it easy to understand the assembling relationship between the transparent base plate 111 as the base material and the color combining prism. As shown in FIG.
Are flat surfaces parallel to the (x, y) plane, and the thickness direction of the transparent flat plate 111 is the z direction. Although it is not necessary to clearly define the x and y directions, in the following description, the left and right width directions in FIG. 1 are assumed to be x directions, and the depth direction is assumed to be y.

The method of manufacturing the color combining prism will be described with reference to the following numbers. (1) First step: preparing a plurality of transparent substrates having the same refractive index. Then, the transparent substrate is polished so that the upper surface and the lower surface parallel to (x, y) are parallel and the thickness is t. The tolerance of the thickness of the transparent flat plate in the z direction may be 100 times or less the thickness of the first or second optical multilayer film described later. Thus, many transparent flat plates 111 are created.

(2) Second step: As shown in FIG. 1A, a blue reflective dichroic multilayer film 112 as a first optical multilayer film is deposited on one polished surface of the transparent flat plate 111.

(3) Third step: As shown in FIG. 1B, a plurality of transparent flat plates 111 are laminated along the z direction so as to sandwich the blue reflective dichroic multilayer film 112, and a transparent adhesive is formed. Bonding, and a rectangular parallelepiped first coupling body 110
Create In addition, the blue reflective dichroic multilayer film 112 may not be formed on the uppermost transparent flat plate 111.

(4) Fourth step: As shown in FIG. 2A, the first combined body 110 is cut into a plurality of planes at a right angle to the joint surface. The pitch of the cut surface at this time is set to t + Δt in consideration of the cutting margin. Then, the left and right surfaces are polished so as to be parallel with the thickness t equal to that of the transparent flat plate 111, thereby forming the second combined body 120.

(5) Fifth Step: As shown in FIG. 2B, a second optical member is provided on one surface parallel to the polished (y, z) plane of each second coupling member 120. A red reflective dichroic multilayer film 122 as a multilayer film is deposited, and
Create 30.

(6) Sixth step: As shown in FIG. 3A, the upper and lower end faces perpendicular to the red reflection dichroic multilayer film 122 are brought into contact with a reference plane (not shown) to form a plurality of steps. Position the third combination 130. Then, the third joints 130 are adhered to each other with a transparent adhesive to form a fourth joint 140 having a rectangular parallelepiped shape. The fourth conjugate 140 is
It becomes an aggregate of quadrangular prisms 141 having square end faces separated by joining surfaces orthogonal to each other. Note that the red reflecting dichroic multilayer film 122 may not be formed on the third combined body 130 located at the left end.

(7) Seventh step: As shown in FIG. 3B, the angle between the blue reflection dichroic multilayer film 112 and the red reflection dichroic multilayer film 122 is set to 45 °.
Further, the fourth combined body 140 is cut along a cutting plane along the y direction so as to pass through the intersection of these optical multilayer films. In this manner, as shown in FIG. 4A, a fifth combined body 150 having a trapezoidal end face is formed. Fifth conjugate 1 obtained
The outer shape of 50 differs for each cut. For example, a quadrangular prism 141
Assuming that the diagonal length of the end face of the fifth joint is d, the fifth joint 150-
1, 150-4, the upper base is a trapezoidal end face with d and the lower base is 3d, and the fifth combination 150-2, 150-3 is a trapezoidal end face with an upper base of 3d and a lower base of 5d.

(8) Eighth process: Next, as shown in FIG. 4A, the fifth coupling bodies 150-1 and 150-4 are formed by combining the blue reflection dichroic multilayer film 112 and the red reflection dichroic multilayer film 122. To 45 ° and through the intersection of these optical multilayer films,
Six sixth combinations 160 are obtained.

Further, as shown in FIG. 4B, the fifth coupling bodies 150-2 and 150-3 are set at 45 ° with respect to the blue reflection dichroic multilayer film 112 and the red reflection dichroic multilayer film 122. Then, cutting is performed so as to pass through the intersections of these optical multilayer films to obtain three sixth combined bodies 160.

As shown in FIG. 5, the end face shape is 5t × 5t.
From the fourth combined body 140, the sectional shape is (√2t × √2
Eight sixth combined bodies 160 in t) are cut out. The sixth combined body 160 is composed of four triangular prism-shaped right-angle prisms 201, 202, 203, and 204. In one of the right-angle prisms 201,
Blue reflective dichroic multilayer film 1 on each surface sandwiching the right angle part
12 and a red reflective dichroic multilayer film 122 are formed. The sixth combined body 160 has a substantially square end face.
The incident direction of the light beam to the optical multilayer film is a direction perpendicular to the side surface of the quadrangular prism.

(9) Ninth Step; Next, FIG.
As shown in (b), the four cut surfaces 151, 152, 161, and 162, which are the side surfaces of the sixth combined body 160, are ground and polished to form a rectangular parallelepiped having predetermined external dimensions.

(10) Tenth step: An antireflection film is deposited on the four polished surfaces of the sixth assembly 160.

From the fifth combination 150 formed so as to pass through the intersection of the blue reflection dichroic multilayer film 112 and the red reflection dichroic multilayer film 122, a color combining prism composed of four triangular prism-shaped right angle prisms Can be created. In addition, as shown in FIG. 6, three triangular prisms and one five prism are formed from the fifth combined body formed so as to pass near the intersection of the blue reflective dichroic multilayer film 112 and the red reflective dichroic multilayer film 122. A color combining prism 360 composed of prisms can also be created. By intentionally changing the cutting position in this way, it is possible to create a color synthesizing prism that makes it easy to determine the light emission side.

According to the manufacturing method as described above, since the transparent flat plate 111 is polished before the two blue reflection dichroic multilayer films 112 are formed, the flatness of the optical multilayer film is very good. Becomes Also, the second combined body 120
After the cut surface is polished, the red reflection dichroic multilayer film 122 is formed, so that the flatness and parallelism of the optical multilayer film can be ensured well. In addition, since none of the four triangular prisms needs to finish the right angle of the right angle portion with strict accuracy, the color combining prism can be manufactured at low cost.

Further, the right-angle portions of the four right-angle prisms are:
Since the two adjacent members are polished in a joined state, the chipping of the edge does not occur. Therefore, the blue reflection dichroic multilayer film 112 and the red reflection dichroic multilayer film 1
The radius of curvature at the intersection of 22 can be made very small.

The blue reflection dichroic multilayer film 112
The angle of intersection between the red reflective dichroic multilayer film 122 and
Even if it slightly deviates from 確保, the flatness of these optical multilayer films is ensured. Therefore, when this color combining prism is provided in a projection type display device using three liquid crystal panels, the convergence of the projected image can be corrected by adjusting the positional relationship of each liquid crystal panel with respect to the color combining prism. In this sense, practically no problem arises even if the perpendicularity of the crossing angles of the optical multilayer films in the color combining prism is not strictly secured.

(Embodiment 2) Next, a method of manufacturing a color combining prism according to Embodiment 2 of the present invention will be described with reference to FIGS.

(1) The fifth combined body 150 is prepared by the same procedure as in the first embodiment. (2) Unlike the first embodiment, as shown in FIG. 3B, the cut surface 151 of the fifth combined body 150 and the cut surface 15
2 is ground and polished. (3) As shown in FIG. 4A, both the blue reflection dichroic multilayer film 112 and the red reflection dichroic multilayer film 122 intersect with each other at an angle of 45 ° and the intersection of these optical multilayer films. Then, the fifth combined body 150 is cut to form the sixth combined body 160. (4) The cut surface 161 which is the right side surface of the sixth combined body 160
Since the cut surface 162 on the left side is an unpolished surface,
At this point, they are individually ground and polished to finish to predetermined dimensions.

(5) An anti-reflection film is deposited on the four polished surfaces 151, 152, 161, and 162 of the sixth combined body 160.

In this way, a color combining prism composed of four triangular prism-shaped right angle prisms can be produced.
If necessary, similarly to the first embodiment, a color combining prism composed of three triangular prisms and one pentagonal prism as shown in FIG. 6 can also be created.

According to the above method, as in the first embodiment, it is possible to inexpensively produce a color synthesizing prism in which two kinds of optical multilayer films have very good flatness. Further, the radius of curvature at the intersection of the blue reflection dichroic multilayer film 112 and the red reflection dichroic multilayer film 122 can be reduced.

Embodiment 3 Next, a method for manufacturing a color combining prism according to Embodiment 3 of the present invention will be described with reference to FIG. FIG. 7 is an explanatory view showing the last manufacturing process of the color combining prism. FIG. 7A is a perspective view of the sixth combined body 160 obtained in the first or second embodiment. The sixth combined body 160 is a prism having a quadrangular prism shape, and includes upper and lower cut surfaces 151 and 152 and left and right cut surfaces 161 and 1.
62. FIG. 7B shows the sixth conjugate 1
A state in which 60 is divided into three to obtain three color combining prisms 400 is shown.

(1) First, a sixth combined body 160 is prepared in exactly the same procedure as in the first or second embodiment. (2) As shown in FIG. 7A, the sixth combined body 160 is cut at the cutting position 402 so as to be orthogonal to the cut surfaces 152 and 161. (3) Next, as shown in FIG.
04 is ground and polished to a predetermined length h. In this way, a color combining prism 400 having a predetermined outer dimension is created. At this time, the processing of the cut surface 403 on the near side and the cut surface 404 on the opposite side may be performed only by grinding.

According to this method, a large number of color synthesizing prisms having very good flatness of the blue reflection dichroic multilayer film 112 and the red reflection dichroic multilayer film 122 can be manufactured in large quantities, and the cost can be reduced.

(Embodiment 4) Next, a method of manufacturing a color combining prism according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 8 is an explanatory view showing a part of the manufacturing process of the color synthesizing prism of the present embodiment. Third coupling body 130 is attached to bonding base 501. It is assumed that a blue reflection dichroic multilayer film 112 and a red reflection dichroic multilayer film 122 are formed in the third coupling body 130 as in the first embodiment.

(1) First, a third combined body 130 is prepared by the same procedure as in the first or second embodiment. (2) As shown in FIG. 8, one end surface of the third combined body 130, that is, the surface on which the blue reflective dichroic multilayer film 112 is formed, is brought into contact with the vertical plane portion 502 of the bonding base 501. Then, a plurality of third combined bodies 13 located above and below
0 is adhered by a transparent adhesive. Thus, the bonding surface 503
A fourth combined body 140 joined by the above is created. (3) Next, a fifth conjugate is prepared by exactly the same procedure as in the first or second embodiment. Further, a sixth combined body is formed, finished to a predetermined outer size, and an antireflection film is deposited. Thus, the color combining prism is finished.

According to this method, if the third combined body 130 is adhered so that the end face thereof is flush, the shape can be substantially the same as that of the first combined body. That is, the blue reflection dichroic multilayer film 112 forms one plane even after the third coupling body 130 is bonded, so that the two types of optical multilayer films have very good flatness.

(Fifth Embodiment) Next, a method of manufacturing a color combining prism according to a fifth embodiment of the present invention will be described with reference to FIGS.

(1) First, the second combined body 120 is prepared by the same procedure as in the first or second embodiment. At this time, in order to identify the cutting order and direction, FIG.
As shown in (a), marks a, b, c, d, and e are applied to the end faces of the second combined body by identification codes. (2) As shown in FIG. 2A, a red reflective dichroic multilayer film 122 is deposited on one parallel-polished surface of the second combined body 120 to form a third combined body 130.

(3) As shown in FIG. 3A, marks a to e provided when the second combined body 120 is formed.
Is used to arrange the third combined body 130 so as to be in the same state as the first combined body 110. Third combination 130
The end face perpendicular to the red reflection dichroic multilayer film 122 of
It is positioned in contact with one reference plane. Then, they are bonded with a transparent adhesive to form a fourth combined body 140.

The fourth combined body 140 is an aggregate of quadrangular prisms 141 separated by joining surfaces orthogonal to each other. 4 for each
A blue reflective dichroic multilayer film 112 and a red reflective dichroic multilayer film 122 are deposited on two adjacent surfaces of the prism 141, and these optical multilayer films are sandwiched between adjacent quadrangular prisms.

(4) The procedure after the creation of the fourth combined body 140 is the same procedure as in the first or second embodiment.

According to such a manufacturing method, the transparent flat plate 1
In step 11, the parallel-polished processing accuracy is the normal precision processing accuracy (for example, an accuracy of about 0.03 / 100 parallelism).
, The deviation of the blue reflective dichroic multilayer film 112 at the intersection of the two types of optical multilayer films is negligible. However, it is assumed that the processing margin Δt for double-side polishing when the second combined body 120 is formed is not extremely large, about 1 to 3 mm. Thus, a color synthesizing prism having good flatness can be obtained.

Embodiment 6 Next, a method of manufacturing a color combining prism according to Embodiment 6 of the present invention will be described with reference to FIGS.
This will be described with reference to FIG. In the present embodiment, FIG.
(A) As shown in FIG.
01 and a transparent flat plate 602 having a long depth are used so as to alternately overlap each other. A blue reflection dichroic multilayer film 612 is formed on the upper surfaces of the transparent flat plate 601 and the transparent flat plate 602.

(1) A plurality of transparent flat plates 601 and 602 having two different depth dimensions and the same refractive index are processed to have a predetermined thickness, and both surfaces are polished in parallel. (2) As shown in FIG.
Blue reflective dichroic multilayer film 612 on one of the polishing surfaces
Is deposited. (3) Next, as shown in FIG. 9B, the transparent flat plates 601 and the transparent flat plates 602 are alternately stacked so as to sandwich the blue reflection dichroic multilayer film 612 therebetween. Then, the respective transparent flat plates are bonded with a transparent adhesive so that substantially the same step is formed at both ends in the y direction. Thus, a first combined body 610 is formed. At this time, the optical flat film may not be deposited on the transparent flat plate 601 or 602 located at the upper end.

(4) As shown in FIG. 10, the first joint body 610 is cut along a plane perpendicular to the joint surface. Then, both surfaces are polished to the same thickness as the transparent flat plates 601 and 602 to form a plurality of second combined bodies 620. At this time, in order to be able to identify the order and direction of cutting later, marks a,
It is preferable to apply b, c, d, and e.

(5) As shown in FIG. 11, a red reflective dichroic multilayer film 622 is deposited on one of the parallel polished surfaces of the second combined body 620 to form a third combined body 630.

(6) As shown in FIG. 12, the third combination 630 is arranged using the mark provided on the second combination 620 so as to be in the same order and direction as when cut. Then, one of the steps formed when the first combined body 610 is formed is brought into contact with the vertical reference plane of the bonding base 642 and positioned. Next, a fourth adhesive is applied by using a transparent adhesive.
Is created. At this time, the optical multilayer film may not be deposited on the third combined body 630 located at the left end. In this way, the fourth combined body 640 becomes an aggregate of quadrangular prisms 641 separated by joining surfaces orthogonal to each other. The red reflective dichroic multilayer 622 and the blue reflective dichroic multilayer 612 are sandwiched between adjacent quadrangular prisms.

(7) As shown in FIG. 13, the blue reflective dichroic multilayer 612 and the red reflective dichroic multilayer 6
The fourth combined body 640 is cut to make a fifth combined body 650 so as to be 45 ° with respect to 22 and to pass through the intersection of these optical multilayer films. At this time, the cut surface includes an intersection of the red reflection dichroic multilayer film 622 and the blue reflection dichroic multilayer film 612 or passes near the intersection.

(8) As shown in FIG. 14, the blue reflective dichroic multilayer 612 and the red reflective dichroic multilayer 6
The fifth combined body 650 is cut so as to form an angle of 45 ° with respect to 22 and to pass through the intersection of these optical multilayer films. In this way, a sixth combined body 660 having unevenness formed on both end surfaces is formed.

(9) The four cut surfaces 651, 652, 661, 662 of the sixth combined body 660 are ground and polished to finish them to predetermined external dimensions.

(10) An antireflection film is deposited on the four polished surfaces of the sixth combined body 660.

In the above procedure, the fifth conjugate 650
May be ground and polished before cutting. At this time, the sixth coupling body 66
Grinding and polishing of 0 may be performed only on the two cut surfaces 661 and 662.

Further, the step formed by the sixth coupling body 660 can be used for positioning when incorporated in a projection display device. Further, the sixth combined body 660 as shown in FIG. 14C is cut so as to have a predetermined depth h, and the cut surface 665 is appropriately finished. In this way, a plurality of color combining prisms can be created from one sixth combined body 660.

According to the manufacturing method of the present embodiment, fourth joint 640 is formed such that the step formed when first joint 610 is formed is one plane. Therefore, the blue reflection dichroic multilayer film 612 and the red reflection dichroic multilayer film 622 in the fourth coupler 640 can form a very good plane. The color synthesizing prism created by such a procedure has a very good flatness of the optical multilayer film, and can reduce the radius of curvature at the intersection.

(Embodiment 7) A projection display device using the color combining prism obtained in the above embodiment will be described below as Embodiment 7 of the present invention. FIG. 15 is an optical path diagram illustrating a schematic configuration of the projection display apparatus according to the present embodiment. The projection type display device includes a light source 1, a plane mirror,
2,5, dichroic mirrors 3,4, relay lenses 6,7, plane mirrors 8,9, field lenses 10,1
1, 12, liquid crystal panels 16, 17, 18, a color combining prism 22, and a projection lens 23.

The light source 1 comprises a lamp 31, a concave mirror 32, and a filter 33. The concave mirror 32 has a spheroidal reflecting surface, reflects visible light forward and transmits infrared light backward. The lamp 31 is arranged such that the center of the light emitter is located at the focal point 35 of the concave mirror 32. The filter 33 is made of a glass substrate, transmits visible light, and reflects infrared light and ultraviolet light. Therefore, an optical multilayer film is deposited on one surface of the glass substrate, and an antireflection film is deposited on the other surface. The white light emitted from the lamp 31 is
The light is converted into near parallel light by the concave mirror 32,
3 directs only visible light to the plane mirror 2.

The light emitted from the light source 1 is reflected by the plane mirror 2, and a part of the light passes through the red transmitting dichroic mirror 3, is reflected by the plane mirror 5, and is reflected by the field lens 10 and the incident side polarized light. The light is incident on the liquid crystal panel 16 via the plate 13 as red light. A part of the light reflected by the dichroic mirror 3 is reflected by the dichroic mirror 4 which reflects green light, and the field lens 11 and the incident side polarizing plate 1 are reflected.
4 and is incident on the liquid crystal panel 17 as green light. Further, a part of the light reflected by the dichroic mirror 3 passes through the dichroic mirror 4 which reflects green, and passes through the plane mirror 8, the relay lens 7, the plane mirror 9, the field lens 12, and the incident side polarizing plate 15 to the liquid crystal panel. 18 is incident as blue light.

Each of the three liquid crystal panels 16, 17, and 18 is a TN liquid crystal panel, and is a light valve that forms an optical image according to the polarization state. Each liquid crystal panel 16,1
The outgoing lights from 7 and 18 are respectively output from the outgoing side polarizing plates 19 and
The light passes through 20 and 21 and enters the color combining prism 22.
As described in the first to sixth embodiments, the color combining prism 22 is formed by joining four triangular prisms such that the red reflection dichroic multilayer film and the blue reflection dichroic multilayer film are arranged in an X shape. is there.

Each primary color light incident on the incident surface of the color combining prism 22 is combined into one light by each optical multilayer film, and then enters the projection lens 23. And the liquid crystal panel 1
The optical images formed on 6, 17, and 18 are enlarged by the projection lens 23 and projected on a screen.

In the configuration shown in FIG. 15, in the optical path length from the light source 1 to each of the liquid crystal panels 16, 17, 18, only the blue optical path is longer than the other optical paths. For this reason, the equivalent optical path length of blue is made equal to the optical path lengths of red and green using a relay lens. This will be described below.

The first relay lens 6 forms a real image corresponding to the concave mirror at the position of the second relay lens 7. The second relay lens 7 converts a real image of approximately the same size corresponding to an object near the first relay lens 6 into a field lens 1.
2 is formed. The field lens 12 forms a real image corresponding to an object near the second relay lens 7 near the pupil of the projection lens 23. Thus, a real image corresponding to the concave mirror can be formed near the pupil of the projection lens 23. The field lenses 10 and 11 also form a real image corresponding to the concave mirror near the pupil of the projection lens 23. Thus, the light emitted from the light source can be efficiently guided to the projection lens 23 in the blue optical path.

In the projection display device shown in FIG. 15, since the two types of dichroic multilayer films in the color combining prism have good flatness, no double image appears in the projected image, and
The displacement of each corresponding pixel of the color projection image can be made very small.

[0083]

As described above, according to the first to seventeenth aspects of the present invention, a color synthesizing prism having two kinds of optical multilayer films having very good flatness can be manufactured at low cost.

According to the eighteenth aspect of the present invention, by using the color synthesizing prism of the above invention as a color synthesizing means, a double image does not appear in the projected image, and each corresponding pixel of the three-color projected image is displayed. Of the projection type display device with very small deviation can be realized.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a method (1) for manufacturing a color combining prism according to Embodiments 1 to 5 of the present invention.

FIG. 2 is an explanatory diagram of a method (part 2) for manufacturing a color combining prism according to the first to fifth embodiments of the present invention.

FIG. 3 is an explanatory diagram of a method (part 3) for manufacturing a color combining prism according to the first to fifth embodiments of the present invention.

FIG. 4 is an explanatory diagram of a method (No. 4) for manufacturing a color combining prism according to Embodiments 1 to 5 of the present invention.

FIG. 5 is an explanatory diagram of a method (part 5) for manufacturing a color combining prism according to the first to fifth embodiments of the present invention.

FIG. 6 is a perspective view showing an example of cutting out a color combining prism according to Embodiments 1 to 5 of the present invention.

FIG. 7 is an explanatory view showing a part of a method of manufacturing a color combining prism according to Embodiment 3 of the present invention.

FIG. 8 is an explanatory view showing a part of a method of manufacturing a color combining prism in Embodiment 4 of the present invention.

FIG. 9 is an explanatory diagram illustrating a method (part 1) for manufacturing a color combining prism according to the sixth embodiment of the present invention.

FIG. 10 is an explanatory diagram showing a method (No. 2) for manufacturing a color combining prism according to the sixth embodiment of the present invention.

FIG. 11 is an explanatory diagram illustrating a method (part 3) for manufacturing a color combining prism according to the sixth embodiment of the present invention.

FIG. 12 is an explanatory diagram illustrating a method (part 4) for manufacturing the color combining prism according to the sixth embodiment of the present invention.

FIG. 13 is an explanatory diagram illustrating a method (part 5) for manufacturing the color combining prism according to the sixth embodiment of the present invention.

FIG. 14 is an explanatory diagram illustrating a method (part 6) for manufacturing the color combining prism according to the sixth embodiment of the present invention.

FIG. 15 is an optical path diagram illustrating a schematic configuration of a projection display apparatus according to Embodiment 7 of the present invention.

FIG. 16 is a perspective view showing a configuration example of a conventional color combining prism.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Light source 2,5,8,9 Planar mirror 3,4 Dichroic mirror 6,7 Relay lens 10,11,12 Field lens 13,14,15 Incident side polarizing plate 16,17,18 Liquid crystal panel 19,20,21 Emission Side polarizing plate 22, 360, 400 Color combining prism 23 Projection lens 31 Lamp 32 Concave mirror 33 Filter 81, 122, 622 Red reflection dichroic multilayer film 82, 112, 612 Blue reflection dichroic multilayer film 83, 84, 85, 86 Right angle prism 110 , 610 First combined body 111, 601, 602 Transparent flat plate 120, 620 Second combined body 130, 630 Third combined body 140, 640 Fourth combined body 141, 641 Quadrangular prism 150, 150-1 to 150 -4,650,650-1
650-4 Fifth combined body 151, 152, 161, 162, 665 Cut plane 160, 660 Sixth combined body 201-204 Right angle prism 501, 542 Lamination base

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03B 33/12 G03B 33/12 H04N 9/31 H04N 9/31 C

Claims (19)

[Claims] When the thickness direction of a transparent substrate having a refractive index n is defined as az direction, and a plane parallel to a (x, y) plane perpendicular to the z direction is defined as a flat surface of the transparent substrate, two opposing surfaces are provided. A first step of polishing the flat plate surfaces so as to be parallel and have a predetermined thickness t to obtain a plurality of transparent flat plates, and a polishing surface of one of the transparent flat plates obtained in the first step,
A second step of forming a first optical multilayer film having a first spectral transmittance characteristic, and using the plurality of transparent flat plates obtained in the second step, the first optical multilayer film is sandwiched. Stacked in the z direction so that
A third step of forming a rectangular parallelepiped first bonded body by bonding using a transparent adhesive; and forming the first bonded body into a plurality of pieces at a cut surface perpendicular to the bonding surface of the third step. A fourth step of cutting and polishing the cut surface to form a second combined body having a thickness in the x direction of t; a polished surface parallel to the (y, z) plane of the second combined body A fifth step of forming a second optical multilayer film having a second spectral transmittance characteristic on one side and forming a third combined body; and forming a plurality of second optical multilayer films so as to sandwich the second optical multilayer film. The third of
Are laminated along the x direction, and the end faces of the third composite are aligned so that the first optical multilayer film forms the same plane parallel to the (x, y) plane. A sixth step of forming a fourth rectangular parallelepiped by joining the first and second optical multilayer films through an intersection of the first optical multilayer film and the second optical multilayer film. 45 ° for 2 optical multilayers
A seventh step of cutting the fourth joint body along a cutting plane parallel to the y-axis to form a polygonal prism-shaped fifth joint body having a trapezoidal end face shape; and the seventh step When cutting the fifth joined body along a cutting plane orthogonal to the cutting plane, the first and second joints are cut at the end face.
An eighth step of determining the cutting position so that the optical multilayer film becomes an orthogonal diagonal line, and forming a quadrangular prism-shaped sixth coupling body having a square end face by the cutting processing; and the sixth coupling A ninth step of obtaining a color combining prism by polishing each cut surface parallel to the y-axis of the body, a method of manufacturing a color combining prism. 2. When a thickness direction of a transparent substrate having a refractive index n is defined as az direction and a plane parallel to a (x, y) plane perpendicular to the z direction is defined as a flat surface of the transparent substrate, two opposing surfaces are provided. A first step of polishing the flat plate surfaces so as to be parallel and have a predetermined thickness t to obtain a plurality of transparent flat plates, and a polishing surface of one of the transparent flat plates obtained in the first step,
A second step of forming a first optical multilayer film having a first spectral transmittance characteristic, and using the plurality of transparent flat plates obtained in the second step, the first optical multilayer film is sandwiched. Stacked in the z direction so that
A third step of forming a rectangular parallelepiped first bonded body by bonding using a transparent adhesive; and forming the first bonded body into a plurality of pieces at a cut surface perpendicular to the bonding surface of the third step. A fourth step of cutting and polishing the cut surface to form a second combined body having a thickness in the x direction of t; a polished surface parallel to the (y, z) plane of the second combined body A fifth step of forming a second optical multilayer film having a second spectral transmittance characteristic on one side and forming a third combined body; and forming a plurality of second optical multilayer films so as to sandwich the second optical multilayer film. The third of
Are laminated along the x direction, and the end faces of the third composite are aligned so that the first optical multilayer film forms the same plane parallel to the (x, y) plane. A sixth step of forming a fourth rectangular parallelepiped joint by joining the first optical multilayer film and the first optical multilayer film through a vicinity of a line of intersection between the first optical multilayer film and the second optical multilayer film. And cutting the fourth combined body at a cutting plane parallel to the y-axis so as to be at 45 ° with respect to the second optical multilayer film to form a polygonal column-shaped fifth combined body having a trapezoidal end surface. A seventh step of cutting, the fifth joint body being cut by a cutting plane orthogonal to the cutting plane of the seventh step, and a sixth step of forming a quadrangular prism having a square or rectangular end surface by the cutting process. Eighth Create Body
And a ninth step of obtaining a color combining prism by polishing each cut surface of the sixth combined body parallel to the y-axis. 3. The method according to claim 1, wherein the sixth combined body produced in the ninth step is cut into predetermined length units at a cutting plane perpendicular to the first and second optical multilayer films. A method for manufacturing a color combining prism according to claim 1. 4. The method according to claim 1, wherein the tolerance of the thickness in the z direction of each transparent flat plate manufactured in the first step is 100 times or less of the thickness of the first or second optical multilayer film. The method for manufacturing a color combining prism according to claim 1 or 2. 5. The second semiconductor device manufactured in the fourth step
3. The method according to claim 1, wherein a thickness tolerance of the combined body in the x direction is 100 times or less of a thickness of the first or second optical multilayer film. 6. The method according to claim 6, wherein in the sixth step, the third combined body is bonded so that one end face of the third combined body parallel to the (x, y) plane is on the same plane. The method for manufacturing a color combining prism according to claim 1 or 2, wherein: 7. The plurality of second semiconductor devices manufactured in the fourth step.
An identification code indicating an arrangement order and a direction is given to the conjugate of the third conjugate, and the third conjugate is used in the sixth step so as to be the same as the cutting order of the second conjugate using the identification code. 3. The method for manufacturing a color synthesizing prism according to claim 1, wherein the color combining prisms are arranged and joined. 8. In a first step, two types of first and second transparent substrates having different lengths in the y direction are used, and a first transparent flat plate having a length w in the y direction and a length in the y direction are used. A second transparent flat plate having a length shorter than w is formed. In the third step, the first transparent flat plate and the second transparent flat plate are so arranged that both end faces parallel to the (y, z) plane are respectively coplanar. The flat plates are alternately laminated, and (x,
3. The method for manufacturing a color combining prism according to claim 1, wherein a first combination having a step formed on an end surface parallel to the z) plane is formed. 9. When the thickness direction of a transparent substrate having a refractive index n is z and its plane is an (x, y) plane, two opposing (x, y) planes are parallel and have a predetermined thickness t. A first step of polishing the transparent substrate to obtain a plurality of transparent flat plates, on one of the polished surfaces of the transparent flat plates obtained in the first step,
A second step of forming a first optical multilayer film having a first spectral transmittance characteristic, and the first step using a plurality of transparent flat plates with the optical multilayer film obtained in the second step. A third step in which the optical multilayer films are laminated in the z direction so as to be sandwiched therebetween and joined using a transparent adhesive to form a first rectangular parallelepiped combined body; and a right angle to the joint surface in the third step A fourth step of cutting the first bonded body into a plurality of pieces at a suitable cut surface and polishing the cut surface to form a second bonded body having a thickness t in the x direction; A fifth step of forming a second optical multilayer film having a second spectral transmittance characteristic on one of the polished surfaces (y, z) of the body to form a third combined body; A plurality of the third combined bodies are stacked in the x direction so that the optical multilayer film is interposed therebetween, and the first optical multilayer film forms the same plane (x, y). A sixth step of aligning the end faces of the third combined body to form a fourth combined body having a rectangular parallelepiped shape by using a transparent adhesive, and forming the fourth combined body with the first optical multilayer film and the second combined body. Passing through the line of intersection with the first optical multilayer film and 45 ° with respect to the first and second optical multilayer films.
The fourth joint body is cut along a cutting surface along the y direction, and the cut surface is ground and polished to form a polygonal prism-shaped fifth joint body having a trapezoidal end surface. Cutting the fifth combined body at a cutting plane along the y direction orthogonal to the cutting plane of the seventh step, and cutting the first and second optical multilayer films at (x, z) end faces. Becomes an orthogonal diagonal,
An eighth step of forming a quadrangular prism-shaped sixth combined body whose end face shape is a square, and polishing an unpolished surface among the cut surfaces of the sixth combined body along the y direction. 9. A method of manufacturing a color combining prism, comprising: a ninth step of obtaining a color combining prism. 10. When the thickness direction of a transparent substrate having a refractive index n is z and its flat surface is an (x, y) plane, two opposing (x, y) planes are parallel and have a predetermined thickness t. A first step of polishing the transparent substrate to obtain a plurality of transparent flat plates, on one of the polished surfaces of the transparent flat plates obtained in the first step,
A second step of forming a first optical multilayer film having a first spectral transmittance characteristic, and the first step using a plurality of transparent flat plates with the optical multilayer film obtained in the second step. A third step in which the optical multilayer films are stacked in the z direction so as to be sandwiched therebetween and joined using a transparent adhesive to form a first rectangular parallelepiped combined body; and a right angle to the joint surface in the third step A fourth step of cutting the first bonded body into a plurality of pieces at a suitable cut surface and polishing the cut surface to form a second bonded body having a thickness t in the x direction; A fifth step of forming a second optical multilayer film having a second spectral transmittance characteristic on one of the polished surfaces (y, z) of the body to form a third combined body; A plurality of the third combined bodies are stacked in the x direction so that the optical multilayer film is interposed therebetween, and the first optical multilayer film forms the same plane (x, y). A sixth step of aligning the end faces of the third combined body to form a fourth combined body having a rectangular parallelepiped shape by using a transparent adhesive, and forming the first optical multilayer film and the second combined body. Passing the vicinity of the line of intersection with the optical multilayer film of the above, cutting the fourth combined body at a cutting plane along the y direction so as to be at 45 ° to the first and second optical multilayer films, Grinding and polishing the cut surface to form a polygonal prism-shaped fifth combined body having a trapezoidal end surface shape.
And cutting the fifth joint body along a cutting plane along the y-direction orthogonal to the cutting plane in the seventh step, and forming a sixth connection in the form of a quadrangular prism whose end surface shape is square or rectangular. An eighth step of forming a body, and a ninth step of obtaining a color combining prism by polishing an unpolished surface among the cut surfaces along the y direction of the sixth combined body. A method of manufacturing a color synthesis prism, which is a feature. 11. The method according to claim 9, wherein the sixth combined body formed in the ninth step is cut into predetermined length units in the y direction. . 12. The method according to claim 1, wherein a tolerance of a thickness in a z direction of each transparent flat plate manufactured in the first step is 100 times or less of a thickness of the first or second optical multilayer film. The method for manufacturing a color combining prism according to claim 9 or 10. 13. The tolerance of the thickness in the x direction of each of the second combined bodies manufactured in the fourth step is the first or the second.
11. The method according to claim 9, wherein the thickness of the optical multilayer film is 100 times or less. 14. The method according to claim 6, wherein in the sixth step, the third joint is bonded so that one end face of the third joint parallel to the (x, y) plane is flush with the other end. The method of manufacturing a color combining prism according to claim 9, wherein: 15. An identification code indicating an arrangement order and a direction is attached to the plurality of second combined bodies manufactured in the fourth step, and the sixth code is used by using the identification code in the sixth step. 10. The method according to claim 9, wherein the third conjugate is arranged and joined so that the cutting order of the second conjugate is the same.
Or a method for producing a color combining prism according to item 10. 16. In a first step, a first transparent flat plate having a long length in the y direction and a first transparent plate having a long length in the y direction are used, using two types of first and second transparent substrates having different lengths in the y direction. Is short second
In the third step, the first transparent flat plate and the second transparent flat plate are alternately laminated so that both end faces of (y, z) are flush with each other, and the bonding of the laminated surfaces is performed. The method according to claim 9 or 10, wherein a first combined body having a step formed on the (x, z) plane is formed by the method. 17. A color synthesizing prism produced by the manufacturing method according to claim 1. Description: 18. A light source that emits light including three primary colors of red, green, and blue; a color separation unit that separates light emitted from the light source into three primary colors of red, green, and blue; Each primary color light emitted from the decomposition means is incident on each,
R, which forms an optical image of three primary colors according to an input video signal,
G, B light valves; color combining means for combining light emitted from the R, G, B light valves with image light having one optical axis; A projection lens for projecting image light onto a screen, wherein the color synthesizing means is a color synthesizing prism created by the manufacturing method according to any one of claims 1 to 16. Projection display device. 19. The projection display device according to claim 18, wherein said R, G, and B light valves are transmissive liquid crystal panels.