JPH1152109A - Production of color synthesizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To permit the combination with lot of the same refractive index and to permit brighter color synthesis by using specific prisms of a joint type. SOLUTION: Four pieces of the prisms 1 to 4 of a rectangular isosceles triangle of the joint type subjected to chamfering of >=1 mm at two points of the one face across the right angle constituting a dichroic prism are stuck to each other. Exact sticking is executed if the sticking of four pieces of the prisms 1 to 4 of the rectangular isosceles triangle of the joint type is executed by utilizing the chamfered part (a) as a reference plane for positioning. The chamfered part (a) is subjected to the chamfering of 2 mm. At this time, the exact and horizontal plane is obtd. when the prisms are joined by bringing the prisms into contact with the surface of a flat jig. The jig is set between the chamfered surfaces of the prism 1 and the prism 2 (between the chamfered surfaces of the prism 3 and the prism 4). Since the non-chamfered planes of the prism 2 and the prism 4 and the plane of the jig are utilized, the orthogonal joint surfaces made completely plane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device which is applied to an image device through a light valve and projects an enlarged image on a screen.

[0002]

2. Description of the Related Art As an optical system of a projection type display device using a liquid crystal light valve, color separation and color synthesis are performed by bonding a dichroic film so that the right-angled portions of four triangular prisms are at the center. What is known is.

[0003] Unless these four prisms are bonded together accurately, the images of the respective colors synthesized via the dichroic prisms are displaced on the screen, resulting in a reduction in image quality. If a step is formed on the bonding surface as shown in FIG. 2, such an obstacle occurs. For this reason, as shown in FIG. 3, the four prisms are changed in length, the steps are provided, and the steps are used as a reference plane for positioning, so that accurate bonding is performed.

[0004]

The bonding method using this step surface can be bonded accurately, but since the length is different, at least two or three types of prisms must be prepared. No. Since it is necessary to combine materials having the same refractive index, it is generally produced from the same raw material lot. For this reason, if one of them is damaged, the other party becomes unusable, resulting in a large loss of an expensive prism. Further, since the shape is different, it is a major obstacle to productivity such as an increase in types of prism production equipment and change in setup. In addition, the step surface is a plus for the required size of the prism, which is one of the obstacles to downsizing of the image device.

[0005] In view of the above, the present invention provides a color synthesizing apparatus using a congruent right-angled isosceles triangular prism in a simple manner.
An object is to enable accurate manufacturing.

[0006]

A dichroic prism is formed by bonding four congruent right-angled isosceles triangular prisms, which are two sides of a right angle and which are chamfered at two places on one side. .

By using the chamfered portion as a reference plane for positioning and bonding four congruent right-angled isosceles triangular prisms, accurate bonding can be achieved.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a perspective view showing a color synthesizing apparatus.

FIG. 4 is a perspective view of the prism alone, and the hatched portion a is chamfered by 2 mm.

FIG. 5 shows the prism 1 attached to the B surface and the prism 2 to the C surface. At this time, as shown in FIG. 5, if the jig 10 is brought into contact with the surface of the flat jig 10 and joined, an accurate and horizontal surface can be obtained.

In the same manner, the surface B of the prism 3 and the prism 4
Paste the C side of

The joined body of the prisms 1 and 2 and the joined body of the prisms 3 and 4 are bonded together using a jig shown in FIG.

In the method shown in FIGS.
The jig is set between the chamfer of the prism 2 and the chamfer of the prism 2 (between the chamfer of the prism 3 and the prism 4). Since the flat surface of the prism 2 and the prism 4 where the chamfer is not used and the flat surface of the jig are used, the orthogonal bonding surface can be made a perfect flat surface.

In the embodiment, the present invention is applied to the color synthesizing apparatus of the liquid crystal projector apparatus.

[0016]

According to the present invention, since congruent prisms are used, a combination of lots having the same refractive index can be made, and clearer color synthesis can be performed. Further, since only one type of prism is sufficient, productivity of a production apparatus, a production process, and the like is greatly improved.

[0017]

[Brief description of the drawings]

FIG. 1 is a perspective view of a color synthesizing apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view illustrating an example of a position shift of the color combining device.

FIG. 3 is a perspective view showing an example of a color synthesizing apparatus that performs bonding using a step surface as a positioning reference.

FIG. 4 is a perspective view of a prism alone.

FIG. 5 is an explanatory diagram showing a process of attaching the B surface of the prism 1 and the C surface of the prism 2 (the B surface of the prism 3 and the C surface of the prism 4).

FIG. 6 is an explanatory diagram of a jig.

FIG. 7 is an explanatory view showing a joining method using the jig of the embodiment.

FIG. 8 is an explanatory view showing a joining method using the jig of the embodiment.

FIG. 9 is a perspective view in which two of four dichroic prisms are not chamfered.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Prism 1 2 Prism 2 3 Prism 3 4 Prism 4 a Chamfered part 10 Flat jig 20 Bonding jig

Claims (3)

[Claims] 1. A color synthesizing apparatus using a dichroic prism having a right-angled isosceles triangular prism having two chamfers of 1 mm or more on one side of a right angle. 2. The color synthesizing apparatus according to claim 1, wherein said chamfered portion is used as a reference for positioning when said four right-angled isosceles triangular prisms are attached to each other. 3. A color synthesizing apparatus according to claim 2, wherein two of the four dichroic prisms are not chamfered.