JPH0572464A - Method for supporting color separating prism and color separating optical system using this method - Google Patents

Abstract

PURPOSE:To obtain the supporting method for a color separating prism which can support the color separating prism consisting of plural prisms with high accuracy in the prescribed position of a supporting member and the color separating optical system using this method. CONSTITUTION:Metallic films and adhesive surfaces 8a, 8b, 9a, 9b laminated with thin solder layers on the surfaces of the metallic films are formed on a part of the incident face, reflection face or exit face 1x of at least one prism 1a of the plural prisms 1a to 1c of the color separating prism 1 having the plural prisms 1a to 1c which reflect an incident luminous flux plural times and separates the luminous flux to plural color light rays. The one prism is mounted to the supporting member 4 having supporting parts 5a, 5b, 6a, 6b which can be welded by soldering in such a manner that the adhesive surfaces 8a, 8b, 9a, 9b of the prism face the supporting parts 5a, 5b, 6a, 6b of the supporting member 4. Meltable metals 10a, 10b are provided between the supporting parts and the adhesive surfaces and thereafter, the meltable metals 10a, 10b are heated to melt, by which the prism 1a is fixed to the supporting member 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for supporting a color separation prism suitable for a color separation system such as a color television camera or a video camera, and a color separation optical system using the same, and more particularly to imaging for a television camera or a video camera. In the apparatus, a color separation prism composed of a plurality of prisms for separating incident light into, for example, three color lights of B, G and R, or into any two color lights is supported at a predetermined position with high accuracy and stability. The present invention relates to a color separation prism supporting method and a color separation optical system using the same.

[0002]

2. Description of the Related Art Conventionally, a color separation prism used in a color separation system of a television camera, a video camera or the like is designed so that a light beam passing through the color separation prism is incident on a predetermined position of an image pickup means with high accuracy. It is required to be supported by a support member.

FIG. 5 is a schematic view of a conventional method for supporting a color separation prism. In the figure, the color separation prism 30 is composed of three prisms 31a, 31b and 31c, and the reflecting surface of each prism is provided with a known dichroic film, whereby incident light is divided into three color lights of B, G and R. The colors are separated.

Generally, prisms 31b and 31c
Are fixed with an adhesive, and the prism 31a and the prism 31b are configured with a slight gap therebetween. The color separation prism 30 is fixed to the prism base 31 with an adhesive such as an epoxy-based or silicon-based adhesive. In the supporting method shown in the figure, there is no mechanical (for example, a pin) reference between the prisms 31a, 31b, 31c and the prism base 31, and the prisms 31a, 31b, 31c are supported only by the strength of the adhesive.

[0005]

In the method of supporting the color separation prism shown in FIG. 5, the prism base is supported by using an epoxy or silicon adhesive.

Therefore, the prism may be displaced due to environmental conditions (for example, temperature change) or mechanical conditions (for example, vibration, impact, etc.), and the relative positional relationship with the prism base 31 may change.

As a result, the optical axes of the respective color lights separated by the color separation prism are displaced, and when the color images are electrically combined by the television camera, the images are displaced and the resolution is lowered, so that a good image is formed. There was a problem that it could not be obtained.

According to the present invention, the prism constituting the color separation prism and the supporting member for supporting the prism are fixedly supported by using a molten metal such as solder to color-separate the incident light from the taking lens to obtain an image pickup surface. It is an object of the present invention to provide a method for supporting a color separation prism having a simple structure capable of highly accurately incident on the above predetermined position, and a color separation optical system using the same.

[0009]

As a method for supporting a color separation prism of the present invention, a plurality of color separation prisms having a plurality of prisms that reflect an incident light beam a plurality of times to perform color separation into a plurality of color lights and emit the color lights are described. Of at least one of the prisms, a metal coating is formed on a part of the incident surface, the reflecting surface, or the exit surface of the prism, and an adhesive surface is formed by laminating a thin solder layer on the metal coating surface. The prism is attached to a supporting member having a possible supporting portion such that the adhesive surface of the prism faces the supporting portion of the supporting member, a molten metal is provided between the supporting portion and the adhesive surface, and then the molten metal is provided. The prism is fixed to the support member by heating and melting.

In the color separation optical system of the present invention, at least one of the plurality of prisms of a color separation prism having a plurality of prisms that reflect an incident light beam a plurality of times to perform color separation into a plurality of color lights and emit the color lights. Part of the incident surface, the reflecting surface, or the exit surface of the one prism is composed of a metal coating and an adhesive surface in which a thin solder layer is laminated on the metal coating surface, and a solder is used as a supporting member for supporting the one prism. Has a support part that can be welded, and the prism and the support member are fixed to each other by a molten metal provided between the support part of the support member and the bonding surface of the prism.

[0011]

1 is a schematic side view of Embodiment 1 of the present invention, and FIG.
1 is a schematic view when viewed from the direction B in FIG. 1, and FIG. 3 is A in FIG.
It is a schematic diagram showing only one of the -A cross-sections for symmetry.

In the figure, reference numeral 1 denotes a color separation prism having three prisms 1a, 1b and 1c, and a reflecting surface between the prisms is provided with a known dichroic film for color separation. 1X, 1Y, 1Z are prisms 1a, 1b, 1
Light-emission surface (emission surface) 1c1 is a light-incidence surface (incident surface) of the prism 1a, and reference numeral 1b1 is a light-incidence surface (incident surface) of the prism 1b. L is incident light that enters the color separation prism 1 from a photographing lens (not shown). 2a, 2b and 2c are color filters for color trimming, and are prisms 1a and 2a, respectively.
The light emission surfaces (emission surfaces) 1X, 1Y, and 1Z of 1b and 1c are bonded.

Reference numerals 3a, 3b and 3c respectively denote solid-state image pickup devices, which are color filters 2a and 2 of the prisms 1a, 1b and 1c.
It is fixed on the surfaces b and 2c. 4 is a color separation prism 1
It is a support member (board) that serves as a mounting reference.

The support member 4 is a prism (1a, 1b, 1
c) and color filters (2a, 2b, 2c) and other materials having a value substantially equal to the linear expansion coefficient of the optical member, such as titanium, permalloy, and ceramics,
The color separation prism 1 is in contact with a predetermined position of the incident surface 1a1 which serves as a reference surface. Reference numerals 5a, 5b, 6a and 6b are support portions of a part of the support member 4, respectively.

The supporting portions 5a and 5b can melt molten metal such as solder for fixing the prism 1a to the supporting member 4. The supporting portions 6a and 6b connect the prism 1b to the supporting member 4
It is possible to melt molten metal such as solder for fixing to.

Reference numeral 7 denotes a tap, through which the color separation prism 1 is attached to a camera housing (not shown). 8
a and 8b are adhesive surfaces formed on the entrance surface 1a1 of the prism 1a, and 9a and 9b are adhesive surfaces formed on the entrance surface 1b1 of the prism 1b, both of which are formed on a polished flat surface. There is. Adhesive surfaces 8a, 8b, 9a, 9b
As will be described later, has a multilayer structure in which a metal coating is provided on a part of the incident surface, and a thin solder layer is further laminated on the metal coating.

Solder is provided in the gap between the adhesive surfaces 8a and 8b of the prism 1a and the support portions 5a and 5b of the support member 4, and in the gap between the adhesive surfaces 9a and 9b of the prism 1b and the support portions 6a and 6b of the support member 4, respectively. The molten metals 10a and 10b such as the above are inserted and heated from the outside to melt the solder, and both are fixed by adhesion.

An optical filter 11 is held by a frame 12 in front of the entrance surface 1a1 of the prism 1a via a support member 4. Reference numeral 13 denotes a dustproof frame, which is made of a compressible material such as silicon rubber or sponge rubber, and is provided in the gap between the support member 4 and the entrance surface 1a1 of the prism 1a, and affects the photographing light flux and other reflected light. Has no holes.

Incidentally, the bonding surface 8a of the prism 1a (1b),
The metal coating provided on 8b, 9a and 9b has a three-layer structure. The metal coating is a prism 1a (1b) as a substrate and a mask having an opening in the shape of the adhered region is applied, the first layer is chrome (Cr) vapor deposition, and the second layer is chrome and nickel (Ni) binary vapor deposition layer. The third layer is a nickel vapor deposition layer, both of which are formed by heating the substrate to about 250 ° C. and vapor deposition. After that, the temperature of the substrate is adjusted to about 7 on the metal coating surface.
A thin solder layer is vapor-deposited at 0 ° C., thereby forming an adhesive surface.

Although the thickness of the adhesive surface varies depending on the application, the total thickness is about 0.2 μm to 0.9 μm.
The solder thin layer may be laminated by a method other than vapor deposition.

In order to support the color separation prism 1 at a predetermined position on the supporting member 4 in this embodiment, first, a prism is formed on the supporting member 4 by using a dedicated tool or a mechanical positioning means (for example, a pin abutting surface). 1a and the two prisms 1b and 1c that have been adhered in advance are the incident surface 1a of the prism 1a.
1 is set as a reference.

At this time, the bonding surface 8 of the prism 1a (1b)
a, 8b (9a, 9b) and supporting portions 5a, 5 of the supporting member 4
It is arranged so that b (6a, 6b) faces each other. Then, the adhesive surfaces 8a, 8b (9a, 9b) and the supporting portions 5a, 5b (6
Molten metal 10a such as cream solder in the gap between a and 6b)
Insert (10b). Then, the molten metal 10a, 10b is heated by a heating means such as a soldering iron, a halogen lamp, or a laser.
Both are fixed by adhesion by melting.

FIG. 4 is a sectional view of the essential portions of Embodiment 2 of the present invention. In the figure, the same elements as those shown in FIGS. 1 to 3 are designated by the same reference numerals.

In the first embodiment, the prism 1 pre-bonded is used.
The incident surface 1b1 of the prism 1b of the prisms 1b and 1c is provided with an adhesive surface and the supporting member 4 is adhered and fixed. However, in this embodiment, the incident surface 1c1 of the prism 1c of the prisms 1b and 1c has the same metal coating as described above. And a thin solder layer is formed to form an adhesive surface 9a
1, 9b1 are configured. And the adhesive surfaces 9a1 and 9b
1 and the supporting portion are bonded by using the solder 10b, whereby the prism 1c and the supporting member 4 are bonded and fixed.

In the above embodiment, the adhesive surface is provided on the entrance surface of the prism, but the same effect can be obtained by providing it on the polished reflecting surface or exit surface having good flatness.

Further, in each of the above embodiments, the case where three prisms are used as color separation prisms and color separation is performed into three colors is shown. However, a two-color separation prism which is formed by two prisms and performs color separation into any two colors is described. It may be.

[0027]

As described above, according to the present invention, the polished flat surface of the prism constituting the color separation prism and the supporting member for supporting the fixed surface are fixed by using molten metal such as solder. By supporting the color separation prism, the incident light from the photographing lens can be color-separated and incident on a predetermined position on the imaging surface with high accuracy, and a method for supporting the color separation prism and a color separation optical system using the same. Can be achieved.

In addition, the present invention uses a fusible metal such as solder, thereby shortening the curing time at the time of bonding, and preventing other unnecessary force from being applied during bonding.
It has the features that high assembly accuracy can be easily obtained, that the strength does not decrease with age, and that it is durable against environmental changes and mechanical external forces.

[Brief description of drawings]

FIG. 1 is a schematic side view of a first embodiment of the present invention.

FIG. 2 is a schematic diagram when viewed from the direction B in FIG.

3 is a schematic cross-sectional view taken along the line AA of FIG.

FIG. 4 is a schematic sectional view of a second embodiment of the present invention.

FIG. 5 is a perspective view of a main part of a conventional color separation optical system.

[Explanation of symbols]

 1 Color separation prism 1a, 1b, 1c Prism 1a1, 1b1, 1c1 Incident surface 1X, 1Y, 1Z Light exit surface 2a, 2b, 2c Color filter 3a, 3b, 3c Solid-state image sensor 4 Support member 5a, 5b, 6a, 6b Support parts 8a, 8b, 9a, 9b Adhesive surfaces 10a, 10b Molten metal (solder)

Claims (6)

[Claims] 1. A color separation prism having a plurality of prisms that reflect an incident light beam a plurality of times to perform color separation into a plurality of color lights, and emit the color lights. At least one prism of the plurality of prisms has an incident surface, a reflection surface, or an emission surface. Part of the metal coating,
An adhesive surface is formed by laminating a thin solder layer on the metal coating surface,
The one prism is mounted on a supporting member having a supporting portion to which solder can be welded so that the adhesive surface of the prism faces the supporting portion of the supporting member, and molten metal is provided between the supporting portion and the adhesive surface. Is provided, and then the molten metal is heated and melted to fix the prism to the supporting member. 2. The method for supporting a color separation prism according to claim 1, wherein both the metal coating and the solder thin layer are formed by a vapor deposition method. 3. The method for supporting a color separation prism according to claim 1, wherein the support member is made of a material having a coefficient of linear expansion substantially equal to that of a glass material such as titanium, permalloy or ceramics. 4. An incident surface or a reflection surface of at least one of the plurality of prisms of a color separation prism having a plurality of prisms that reflect an incident light beam a plurality of times to perform color separation into a plurality of color lights for emission. A part of the emission surface is composed of a metal film and an adhesive surface in which a thin solder layer is laminated on the metal film surface, and a support member for supporting the one prism has a support portion to which solder can be welded. A color separation optical system characterized in that the prism and the supporting member are fixed to each other by a molten metal provided between the supporting portion of the supporting member and the bonding surface of the prism. 5. The color separation optical system according to claim 4, wherein both the metal coating and the solder thin layer are formed by a vapor deposition method. 6. The color separation optical system according to claim 4, wherein the support member is made of a material having a linear expansion coefficient substantially equal to that of a glass material such as titanium, permalloy or ceramics.