JPH1039119A - Manufacture of combined prism, and stuck prism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for rapidly producing a stuck prism of which respective ridge lines holding a right angle are nearly aligned, of which end faces of four pieces of prisms are trued up, and with which the synthesized colors of exact colors with the decreased misalignment of the red, blue and green colors are obtainable at a high yield without requiring high skill. SOLUTION: The ridge line between the one flank and at least one end face of a first rectangular prism 12 is previously provided with a notch. Further, the first rectangular prism is placed together with a second rectangular prism 11 on a plane substrate in such a manner that the end faces thereof come into contact with the substrate. The flanks of both are stuck to each other. A pair of prisms to be stuck exposing the ends G of the flanks of the second rectangular prism by the notch F of the first rectangular prism are formed symmetrically with respect to plane. The flanks of the adhered prisms are stuck to each other by regulating the end faces D of a pair of the adhered prisms by the plane and pressing and aligning the ends G exposed by the notches at the flanks of two pieces of the second rectangular prisms to the plane of a guide, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a bonded prism in which four right-angle prisms are bonded such that ridges sandwiched between the right angles are aligned or parallel to each other, and manufactured by the method. The present invention relates to a bonding prism. This laminated prism is particularly suitable for use in color separation and synthesis of a liquid crystal projector, which is one type of projection display.

[0002]

2. Description of the Related Art Heretofore, a device using a dichroic mirror and a bonding prism having a dichroic mirror function according to the present invention are used for a device for separating and synthesizing colors of a liquid crystal projector, which is one of the projection type displays. There are things. The method of using the bonding prism is to separate and combine colors by providing a dichroic mirror function to the bonding surface of the right-angle prism, but this method uses light generated due to the thickness of the dichroic mirror. Since there is no aberration, a highly accurate image can be obtained as compared with a method using a dichroic mirror.

FIG. 11 is a schematic diagram showing a prism type color synthesizing mechanism. A red image projected from the liquid crystal element 1 having a red signal is vertically reflected by a surface 2 having a dichroic mirror function for reflecting red. A blue image projected from the liquid crystal element 3 having a blue signal is vertically reflected in the same direction as the red image by a surface 4 having a dichroic mirror function for reflecting blue. The green image projected from the liquid crystal element 5 having a green signal passes through a surface 4 having a dichroic mirror function for reflecting blue and a surface 2 having a dichroic mirror function for reflecting red, and is the same as a blue image or a red image. Projected to the front. The red, blue, and green images thus obtained are combined by the bonding prism, and projected as a color image on a front screen through a lens.

A prism having a dichroic mirror function as described above is manufactured by applying a film having a dichroic mirror function to a bonding surface of the prisms and bonding them together. If the ridge lines formed by the right-angled vertices of the cross-section triangles of the four right-angled prisms are not aligned or parallel to each other, the red, blue, and green images will be displaced, resulting in accurate color synthesis. No image can be obtained. For example, if the ridges of the four right-angle prisms are not positioned in parallel, the side surfaces of the right-angle prisms have inclinations with respect to each other. The image is projected and a color-shifted image is formed on the screen. For this reason, the four right-angle prisms have exactly one side face across the right angle.
It is necessary to intersect vertically with the straight lines.

[0005] It is relatively easy to bond two right-angle prisms so that their side surfaces are on a plane to form an adhesive prism. However, the ridge line of the right-angle prism is included in the plane of the adhesive prism, and a step or the like is formed. Since there is no clear section such as a projection, it is difficult to match the ridge lines of the four prisms when two adhesive prisms are combined. However, in the past, without using any special jigs, the ridges sandwiching the right angles of the four right-angle prisms were carefully attached so that the ridge lines sandwiching the right angles were gathered into one straight line, and then bonded together. Was. For this reason, a skilled worker is required for the production, and it takes a long time to perform the bonding, and the yield is not good.

To solve such a problem, Japanese Patent Laid-Open Publication No. Hei.
JP-A-138603 discloses a right-angle prism using a jig based on a step formed when right-angle prisms having different thicknesses are adhered side by side or a step formed by shifting right-angle prisms having the same thickness to each other. A method has been proposed in which the ridges are positioned so as to match the ridges and bonded together. In this way, a highly accurate bonded prism can be obtained without using an optical system such as a microscope even without a high level of skill. Japanese Unexamined Patent Publication No. Hei 7-294845 discloses a bonded prism in which at least one right-angle prism whose width is wider than other right-angle prisms is bonded so that some of the prisms protrude from an end surface. ing. However, the bonded prisms produced by these methods have irregularities due to steps on the end faces, and when a prism having such a special outer shape is to be installed in a device, a special holding tool adapted to the prism is required. It becomes necessary to prepare. In order to align these end faces, both ends must be cut and polished, which increases the number of steps and results in high cost.

[0007]

Accordingly, the problem to be solved by the present invention is that the end faces of the four prisms are aligned, and the ridges sandwiching the right angle are almost coincident, and the red, blue, and green images are formed. It is an object of the present invention to provide a bonded prism capable of obtaining an accurate color composite image with a small displacement, and to provide a method capable of producing the bonded prism in a short time and with a high yield without requiring high skill. .

[0008]

In order to solve the above-mentioned problems, a method of bonding a right-angle prism according to the present invention is characterized in that a notch is provided in advance on a ridge line which forms one side surface of at least one end surface of a first right-angle prism. Further, the second right-angle prism is mounted together with the second right-angle prism so that the end surfaces thereof are in contact with each other, and the two side surfaces are attached to each other. A pair of prisms are formed in plane symmetry, the end faces of the pair of bonded prisms are regulated by a flat surface, and the end portions exposed by the side cutouts of the two second right-angle prisms are brought into contact with a flat surface such as a guide. It is characterized in that the side surfaces of the adhesive prism are bonded together after being aligned.

In the method for manufacturing a bonded prism according to the present invention, a right-angled prism having a right-angled triangular cross section is used.
The first side wall of the first right-angle prism is provided with a notch at least at the first end face and the first side surface, and the second side surface of the first right-angle prism and the first side surface of the second right-angle prism are connected to each other. Bonding the first side surface of the first right-angle prism and the second side surface of the second right-angle prism while restricting them by the first plane and restricting the end faces of both right-angle prisms by a second plane perpendicular to the first plane. To form a first adhesive prism. In the first adhesive prism, an end of the side surface of the second right-angle prism appears due to the cutout of the first right-angle prism, and the second side surface of the first right-angle prism and the first side surface of the second right-angle prism form one joint surface. ing. Similarly, a second bonded prism having a plane symmetry with the first bonded prism is formed using the third right-angle prism and the fourth right-angle prism, and an end surface of the first bonded prism and an end surface of the second bonded prism are formed. The end faces of the side faces of the second right-angle prism and the end faces of the side faces of the fourth right-angle prism which are restricted by the third plane are restricted by the fourth plane, and the bonding surfaces of the adhesive prisms are bonded to each other. It is characterized by the following.

The first and third right-angle prisms may be provided with cutouts at both the first and second end faces, which are formed on the ridges formed by the first side face. In addition, notches may be provided on both the ridges forming the first side surface and the ridges forming the second side surface on the first end surfaces of all four right-angle prisms. Here, the cutout of the end face may be formed over the entire end face, or may be formed on only a part of the end face.

Further, in order to solve the above-mentioned problems, the bonded prism of the present invention is configured such that ridges formed by vertices sandwiched between right angles of a triangular cross section of four right-angle prisms coincide with each other. One end face has a notch along a diagonal line, and the end of the side surface of the two right-angle prisms appears on one wall of the notch.

According to the right-angle prism bonding method of the present invention, a cutout portion is provided at one end face of one of the two right-angle prisms to be bonded, so that the two prisms are bonded to form a bonded prism. Then, the end of the side surface of the other right-angle prism appears in the notch. The end of this side surface is an extension of the surface having a dichroic mirror function formed in the adhesive prism. Therefore, the dichroic mirror function can be achieved by positioning the two side surfaces so as to be on one plane and bonding the adhesive prisms based on the side end portions that appear in the cutout portions of the two adhesive prisms. It is possible to fabricate a bonded prism in which surfaces having are strictly intersecting in a straight line. Moreover, according to the method of the present invention, it is sufficient to use four right-angle prisms of the same length, and it is only special to cut out a part of the end faces of the prisms a little. Since only a small groove is formed on the flat end surface, it is easy to incorporate the device into a device such as a liquid crystal projector.

Further, according to the method of the present invention, when the two right-angle prisms are first bonded together to form an adhesive prism, the side surface of the right-angle prism having the notch appears and the other right-angled prism. Align the side surfaces of the prisms, place the other side surface of each right-angle prism on a surface such as one flat substrate, and regulate the surface. Furthermore, there is no notch with the end surface of the first right-angle prism that has a notch After regulating the end face of the second right-angle prism with another plane such as a face having a guide, the combined side faces are bonded together to form an adhesive prism. Therefore, even without special skill, it is possible to easily and accurately manufacture an adhesive prism having a flat end face and an extension of the dichroic mirror function surface formed in the adhesive prism exposed at the end face. At this time, by adjusting the cutout position of the right-angle prism and the orientation of the prism, a pair of bonded prisms that are symmetrical with each other are manufactured. In the adhesive prism manufactured here, two side surfaces other than the side surfaces to be bonded to each other form one continuous surface, and serve as a bonding surface for bonding to another adhesive prism. This joint surface has a perpendicular relationship to the bonded side surface. It goes without saying that the same effect can be obtained even if the end face opposite to the end face is restricted by a flat surface.

Next, a pair of adhesive prisms formed in plane symmetry by the above method is used, the end faces are mounted on a flat substrate, the joining surfaces of the two adhesive prisms are aligned, and the two adhesive prisms are cut out. The exposed side surfaces are brought into contact with a flat surface such as a guide so as to be aligned, and the joining surfaces are joined. Therefore, a bonded prism can be obtained in which the dichroic mirror function surface formed in the adhesive prism is perpendicular to the bonding surface, and the ridge lines of the four right-angle prisms are almost coincident. The bonding surface of the two adhesive prisms becomes a dichroic mirror function surface.

When color separation and synthesis are performed using the bonding prism manufactured as described above, an accurate color synthesized image without deviation of red, blue and green images can be obtained. Further, since the positioning prism is manufactured by using the plane of the flat substrate and the plane of the guide, the bonded prism of the present invention can be manufactured in a short time and with a high yield without requiring high skill. Furthermore, since the end faces of each right-angle prism are placed directly on a flat surface such as a flat board and aligned to align the end faces, both ends of the bonded prism, which were required in the conventional method to cut and flatten the end faces with steps, were used. The step of cutting and polishing can be omitted, and as a result, a bonded prism can be produced at low cost.

If notches are provided at both ridges of both end surfaces which are in contact with one side surface of the first right-angle prism, the adhesive prism formed by bonding to the second right-angle prism has notches at both ends. Since it appears on the end face, there is no need to manufacture two types of bonded prisms in consideration of the orientation of the first right-angle prism, and one type of bonded prism made by the same method is turned upside down so that it is plane-symmetric with each other. If they are arranged and joined together, the desired bonded prism can be created. Therefore, the number of right-angle prisms to be prepared is reduced to two types, and the bonding process can be performed mechanically, thereby solving the problem of process management. Furthermore, a notch is provided on both ridge lines sandwiching the right angle of both end faces that are in contact with one side face of all the right-angle prisms, and there is no notch in the second right-angle prism and the side face that does not reach the end face due to the notch in the first right-angle prism. In a case where the side surfaces reaching the end surface are aligned and bonded together, there is an advantage that the manufacturing process and management can be further simplified since only one kind of right-angle prism may be prepared. Note that the same effect can be obtained by using a right-angle prism in which a notch is provided in both the ridge forming the first side surface and the ridge forming the second side surface in the first end surface. Here, the cutout of the end face may be formed over the entire end face, or may be formed on only a part of the end face. This is because technically, a dichroic mirror function surface formed inside the adhesive prism appears, and it is sufficient if it can be regulated by a surface such as a guide.

Further, in order to solve the above-mentioned problems, the bonded prism of the present invention is configured such that ridges formed by vertices sandwiched between right angles of a triangular cross section of the four right-angle prisms coincide with each other. One end face has a notch along a diagonal line, and the end of the side surface of the two right-angle prisms appears on one wall of the notch. Here, the cutout of the end face may be formed over the entire end face, or may be formed by tapering only a part of the end face. The cross section of the cutout may have an appropriate shape such as a triangle, a square, or a semicircle as long as a part of the side surface of the right-angle prism to be bonded is exposed to the cutout. The bonded prism of the present invention can be easily manufactured using a simple jig using the side surface exposed to the cutout of the end face, and is flat without any step on the end face. It is also easy to incorporate into a device such as a projector. In addition, when incorporated in a device such as a liquid crystal projector, the dichroic mirror function surface can be arranged so as to be accurately centered on the optical axis by using the side surface exposed to the cutout portion of the end surface.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A bonded prism according to the present invention will be described below in detail with reference to the drawings based on embodiments.

[0019]

[Embodiment 1] FIG. 1 shows one example of a bonded prism of the present invention.
It is a perspective view showing an example. The bonded prism of the present invention includes a first right-angle prism 11 and a second right-angle prism 1.
It is formed by a second, third right-angle prism 13 and a fourth right-angle prism 14. The joining surfaces between the right-angle prisms each have a dichroic mirror function, and the whole bonded prism has the function of color separation or color synthesis described above with reference to FIG. Further, the second right-angle prism 12 and the fourth right-angle prism 14 have a notch F at an end face D, and the first right-angle prism 11 and the third right-angle prism 13 are bonded to each other at the end G of the side face. It is exposed in the notch.

FIG. 2 is a perspective view of the first and third right-angle prisms 11 and 13 used for the bonded prism of this embodiment. Optical glass BK7 was used as a material. BK7
Is the refractive index nd1.51112, Abbe number νd60.5
Is an optical glass having the following optical characteristics. The cross section of the right-angle prism has a length of the equilateral b of 50.0 mm and a length of the hypotenuse c of 7
It is a right-angled isosceles triangle of 0.7 mm, and the length of a ridge line a formed by vertexes sandwiching the right angle, that is, the thickness of the prism is set to 70.7 mm. The right-angle prism has a first side surface A and a second side surface B orthogonal to each other with a ridge line a interposed therebetween, a slope C formed by a hypotenuse c, a first end surface D, and a second end surface E.

FIG. 3 is a perspective view of a second right-angle prism 12 provided with a notch, among the right-angle prisms used in this embodiment. The notch surface F is provided in the first end surface D along the ridge formed with the first side surface A in a tapered shape at an angle of 45 ° from a position approximately 10 mm away from each surface. The fourth right-angled prism 14 used in the present embodiment has the cutout surface F formed by the second right-angled prism so as to be plane-symmetric with the first right-angled prism.
The end face E is provided along a ridge formed by the first side face A.

FIG. 4 is a plan view showing the arrangement of the four right-angle prisms in the bonded prism, as viewed from the direction of the ridge line a. An optical multilayer film having a dichroic mirror function of reflecting blue is applied to a first side surface 1A serving as an adhesion surface of the first right-angle prism 11,
An optical multilayer film having a dichroic mirror function of reflecting red is provided on the second side surface 1B. An antireflection film is provided on the slope 1C facing the ridge. Also, the second
The second side surface 2B of the right-angle prism 12 is provided with an optical multilayer film having a dichroic mirror function for reflecting red, and the inclined surface 2C is provided with an antireflection film. The first side surface 3A of the third right-angle prism 13 is provided with an optical multilayer film having a dichroic mirror function for reflecting blue, and the inclined surface 3C is provided with an antireflection film. An antireflection film is formed on the slope 4C facing the ridge line of the fourth right-angle prism 14. The first side surfaces of the first right-angle prism 11 and the second right-angle prism 12 and the first side surfaces of the third right-angle prism 13 and the fourth right-angle prism 14 are bonded to each other, and the first right-angle prism 11 and the third right-angle prism 13 are bonded.
Are adhered to each other, and the second side surfaces of the second right-angle prism 12 and the fourth right-angle prism 14 are adhered to each other to complete the pasting prism of FIG.

FIG. 5 is a perspective view showing a first-stage bonding method. First, an adhesive made of an ultraviolet curable resin is applied to the first side surface 1A of the first right-angle prism 11 and the first side surface 2A of the second right-angle prism 12 provided with the cutout surface 2F. The second side surface 1B of the right-angle prism 11 and the second side surface 2B of the second right-angle prism 12 were placed down. In addition, the end faces of both right-angle prisms on the opposite side of the cutout face 2F were arranged so as to be aligned. The flat substrate 17 is a disk made of quartz glass having a diameter of 300 mmΦ, and has a flatness of 100 mm.
mm was ² per Newton one below. The first side surface 1A of the first right-angle prism 11 to which the adhesive has been applied and the first side surface 2A of the second right-angle prism 12 are brought into close contact with each other, irradiated with ultraviolet light, and cured to bond both surfaces. Obtained. The first bonding prism 21 has a dichroic mirror function for reflecting the blue color on the joint surface between the first side surfaces of the two right-angle prisms, and the second bonding prism 21 appears on the surface.
The side surface has a dichroic mirror function to reflect red. The end face has a notch perpendicular to the side face, and the end face 1A of the first side face 1A of the first right-angle prism 11 is provided.
G is exposed in the notch, and indicates the position of the blue reflecting dichroic mirror function surface.

Although not shown, similarly, an adhesive made of an ultraviolet curable resin is applied to the first side surface 3A of the third right angle prism 13 and the first side surface 4A of the fourth right angle prism 14 provided with the notch 4F. , The third right-angle prism 1 on the flat substrate 7
3 and the second side surface 4 of the fourth right-angle prism 14
B was placed on its bottom. The first side surface 3A of the third right-angle prism 13 to which the adhesive has been applied and the first side surface of the fourth right-angle prism 14
The side surfaces 4A were brought into close contact with each other and irradiated with ultraviolet rays to bond both surfaces to obtain a second bonded prism 22. The second bonding prism 22 has a shape in which the bonding surface between the first side surfaces of the two right-angle prisms is a blue reflecting dichroic mirror function surface, and has a shape that is plane-symmetric with the first bonding prism 21, and is a dichroic mirror. The end 3G of the first side surface 3A of the third right-angle prism 13 serving as a functional surface is exposed to a cutout portion perpendicular to the side surface of the end surface. Second adhesive prism 2
2 and the first adhesive prism 21 are plane-symmetric, so that when the second side surfaces are joined together, the end portion 3G becomes the first right-angle prism 1
1 will face in the same direction as the end 1G.

FIG. 6 is a perspective view showing a second stage bonding method. The first bonding prism 21 and the second bonding prism 22 obtained in the first bonding step are connected to the second side surfaces 1B, 2B of the first bonding prism 21 with the cut-out end faces of both bonding prisms facing upward. The second adhesive prism 22 was placed on the flat substrate 17 so as to face the second side surfaces 3B and 4B. At this time, the second side surfaces 1B, 2B of the first adhesive prism 21 and the second side surfaces 3B, 4B,
B was coated with an ultraviolet curable adhesive. At the time of mounting, the flat surfaces of the guide 19 are brought into contact with the upper ends 1G, 3G of the first side surfaces exposed by the notches F provided in the first and second adhesive prisms so that the first side surfaces are aligned on one plane. Further, the bonded surfaces were brought into contact with each other and irradiated with ultraviolet rays to perform bonding, thereby obtaining a bonded prism. Although the thus obtained laminated prism was manufactured by a person with low skill, the image was projected by incorporating it into a liquid crystal projector, and as a result, a high quality projected image with almost no color shift was obtained.

[0026]

[Embodiment 2] The bonded prism of this embodiment is the same as that of Embodiment 1.
A rectangular prism similar to the above is used, but the shape of the notch is different. The notch in this embodiment has a cross section of about 10 m in width.
m, a rectangular groove having a depth of 5 mm. In this embodiment, the first right prism 31 and the second right prism 32 are bonded to form a first bonded prism 41,
The first-stage bonding method for manufacturing the second bonded prism 42 by bonding the third right-angle prism 33 and the fourth right-angle prism 34 is exactly the same as that in the first embodiment, and therefore the description of the process is omitted. I do. The first end face of the obtained first adhesive prism 41 has a groove-shaped notch perpendicular to the side face, and the end G of the first side face A of the first right-angle prism 31.
Is exposed in the notch. Second adhesive prism 4
2 has a plane-symmetric shape with respect to the first adhesive prism 41.

FIG. 7 is a perspective view showing a second-stage bonding method in the bonded prism of this embodiment. The first adhesive prism 41 and the second adhesive prism 42 obtained by the first-stage bonding are coated with an ultraviolet-curable adhesive with the first end faces having the cutouts of both the adhesive prisms facing up. The flat substrate 17 is arranged such that the second side surface B of the first adhesive prism 41 and the second side surface B of the second adhesive prism 42 face each other.
Placed on top. At the time of mounting, the upper end portion G of the first side surface exposed to the groove-shaped notch portion in the first and second adhesive prisms
First, the first side surfaces are aligned on one plane by abutting the plane of a rectangular rod-shaped guide 39 having a rectangular cross section, and then the bonded surfaces are brought into contact with each other and irradiated with ultraviolet rays to be bonded and bonded. I got Since the bonded prism of the present embodiment uses a guide having a rectangular cross section, the reference plane can be positioned firmly and firmly.
The notch can be made shallower, which has the effect of increasing the effective width of the prism. Although the thus obtained laminated prism was manufactured by a person with low skill, the image was projected by incorporating it into a liquid crystal projector, and as a result, a high quality projected image with almost no color shift was obtained.

[0028]

Embodiment 3 In each of the above embodiments, since a pair of plane-symmetric adhesive prisms is manufactured, it is necessary to change the position of the cutout portion of the right-angle prism, and eventually, three types of right-angle prisms are prepared. is what happened. The bonding prism of the present embodiment reduces the types of right-angle prisms to be prepared by devising cutout positions of the right-angle prisms,
This facilitates the production and management of intermediate parts and saves production costs. The bonded prism shown in FIG. 8 has two ends perpendicularly intersecting the first side surface at both end surfaces of the right-angle prism.
A notch is provided in the ridge of the book, and this is
By using the prism as the second prism and turning it upside down and using it as the fourth right-angle prism 54, two types of right-angle prisms, one without a notch and one with a notch, can be prepared. The method of manufacturing a bonded prism using these right-angle prisms is exactly the same as in the case of the first and second embodiments, and a description thereof will be omitted. The laminated prism thus formed has a dichroic mirror function surface on one end surface, and the same dichroic mirror function surface also appears on the opposite end surface. By doing so, there is also an advantage that the position of the center line of the prism can be accurately determined.

The bonding prism shown in FIG. 9 uses only a right-angle prism having two notches shown in FIG. 8 and appropriately selects and combines the directions of the right-angle prism to form a first right-angle prism. The prism 61, the second right-angle prism 62, the third right-angle prism 63, and the fourth right-angle prism 64 are formed into a bonded prism by regulating the position on a plane and bonding them together. Since the end portion G of the dichroic mirror function surface appears on the end surface as in each of the above-described embodiments, it is possible to easily obtain a bonded prism in which the two dichroic mirror function surfaces cross exactly vertically. Since this bonded prism is composed of only one kind of right angle prism, the intermediate parts can be manufactured more mechanically, the management becomes simpler, and there is an advantage that the whole manufacturing cost can be reduced. As shown in FIG. 10, four ridges each having a cutout at each of a ridge formed by the first end face of the right-angled prism intersecting with the first side face and a ridge formed by intersecting with the second side face were prepared. Even if the position and orientation are appropriately selected so as to correspond to each of the four right-angle prisms, a bonded prism composed of one type of right-angle prism can be obtained. The bonded prism of the present invention is not limited to a liquid crystal projector, but is incorporated into various devices such as a colorimeter and a color printer to perform color separation and color separation.
It goes without saying that color synthesis can be performed.

[0030]

As described above, the bonded prism of the present invention uses the fact that the dichroic mirror function surface formed in the prism appears at the end face so that the dichroic mirror function surfaces intersect perpendicularly exactly. It can be installed in a device such as a liquid crystal projector so that the red, blue and green images
Can be used to perform synthesis. In addition, the method for producing a bonded prism of the present invention does not require high skill,
It is possible to produce a bonded prism in a short time and with a high yield. Furthermore, since the surfaces generated by the notches are aligned by the guides, the end surfaces can be aligned, so that the step of cutting and polishing both ends can be omitted, and the number of steps can be prevented, and as a result, a low-cost bonded prism can be manufactured. .

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating a bonded prism according to a first embodiment of the present invention.

FIG. 2 is a perspective view of a first type of right angle prism used in the first embodiment.

FIG. 3 is a perspective view of a second type of right angle prism used in the first embodiment.

FIG. 4 is a plan view showing an arrangement of right-angle prisms in the bonded prism according to the first embodiment.

FIG. 5 is a perspective view illustrating a first-stage bonding method in the method of manufacturing the bonded prism according to the first embodiment.

FIG. 6 is a perspective view showing a second-stage bonding method in the method of manufacturing the bonded prism according to the first embodiment.

FIG. 7 is a perspective view illustrating a second-stage bonding method in the method of manufacturing the bonded prism according to the second embodiment of the present invention.

FIG. 8 is a perspective view showing a bonded prism according to Embodiment 3 of the present invention.

FIG. 9 is a perspective view showing another embodiment of the bonded prism of the third embodiment.

FIG. 10 is a perspective view showing still another embodiment of the bonded prism according to the third embodiment.

FIG. 11 is a conceptual diagram showing a mechanism of prism type color synthesis.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 red liquid crystal element 2 red reflective dichroic mirror functional surface 3 blue reflective liquid crystal element 4 blue reflective dichroic mirror functional surface 5 green liquid crystal element 11, 21, 31, 41, 61 first right-angle prism 12, 22, 32, 42, 52, 62 Second right-angle prism 13, 33, 63 Third right-angle prism 14, 34, 54, 64 Fourth right-angle prism 17 Flat substrate 19 Guide 39 Square rod-shaped guide a Ridge line b Equilateral c Oblique side A First side surface or blue reflective dichroic Mirror function optical multilayer film B Second side or red reflective dichroic mirror function optical multilayer film C Slope or anti-reflection film D First end face E Second end face F Notch face G First side end

Claims (5)

[Claims] 1. A method for producing a bonded prism by bonding four right-angle prisms with their ridges having right angles coincident with each other, wherein a notch is formed in one edge of one end surface of at least one right-angle prism. The two right-angle prisms are placed on a flat substrate and bonded to form an adhesive prism in which a part of the side surface of one of the right-angle prisms appears. A method of manufacturing a bonded prism, wherein side surfaces of a right-angle prism appearing by the notch are aligned and bonded by a guide. 2. A method of producing a bonded prism by bonding together such that ridges formed by vertices sandwiched between right angles of a triangular cross section of the four right-angle prisms are equal to each other. A prism is provided, and a notch is provided at an edge formed by at least a first end surface of the first right-angle prism and a first side surface, and a second side surface of the first right-angle prism and a first side surface of the second right-angle prism are provided. Is regulated by the first plane, and the end faces of both right-angle prisms are regulated by the second plane perpendicular to the first plane, and the first side surface of the first right-angle prism and the second side surface of the second right-angle prism are bonded to each other. As a result, the end of the side surface of the second right-angle prism appears due to the cutout of the first right-angle prism, and the second side surface of the first right-angle prism and the second side surface of the second right-angle prism.
A first side in which the first side surface of the right-angle prism forms one joint surface
Similarly, the end of the side surface of the fourth right-angle prism appears due to the cutout of the third right-angle prism, and the second side surface of the third right-angle prism and the first side surface of the fourth right-angle prism are similarly formed. Forming a single bonding surface to form a second bonding prism having a plane symmetry with the first bonding prism, defining end surfaces of the first and second bonding prisms with a third plane, and appearing by notches. A bonding prism manufacturing method, characterized in that the end of the side surface of the second right-angle prism and the end of the side surface of the fourth right-angle prism are regulated by a fourth plane, and the bonding surfaces of the adhesive prisms are bonded to each other. 3. The method for producing a bonded prism according to claim 1, wherein both the first and second right-angle prisms have notches formed on both the first and second end surfaces and the ridge formed with the first side surface. A method for producing a bonded prism, comprising: 4. The method for producing a bonded prism according to claim 1, wherein the two right-angled prisms have notches at both edges forming first and second side surfaces of the first end surface. A method for producing a bonded prism, comprising: 5. A bonded prism configured such that ridges formed by vertices sandwiched between right angles of a triangular cross section in four right-angle prisms have notches along at least one end face along a diagonal line. A bonded prism characterized in that a part of side surfaces of two right-angle prisms appears on one wall of the notch.