JPS63120574A - Color separation optical system - Google Patents

Abstract

PURPOSE:To prevent any change in the positional relation among prisms under the influence of heat by supporting the contact plane of each prism constituting a prism group in abutting on plural protruding parts provided adjustablly in height on a prism base plate. CONSTITUTION:The prisms 3-5 are disposed in using the light-passing plane as reference, and adhered to the prism base plate 2 with an adhesive 11 made of such as resin adhesive, etc. To the prism base plate 2, plural pieces of screws 22 are provided for each prism 3-5 as above-said height-adjustable protruding parts; the juncture planes 10 between the prisms 3-5 are abutted on the screws 22 at their extremes; the juncture planes 10 are thus supported by the screws 22 that are uniformly disposed in a manner that the screws 22 are at the apexes of a triangle, on lines extended from which are the apexes of the juncture planes 10 of the prisms 3-5. Accordingly, in case a thermal change occurs in the titled system, the juncture planes 10 are supported by the screws 22 at uniformly disposed three locations. As a result, the stresses occurring in the prisms 3-5 are made equal at the juncture planes 10, hence irregular deforming of the prisms 3-5 due to thermal expansion/contraction can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is directed to a color television camera which divides incident light into a plurality of optical paths by a group of prisms and receives each output light of the group of prisms by a plurality of solid-state image sensors. Regarding the resolving optical system.

BACKGROUND ART Page 2 Conventionally, as this type of color separation optical system, the configurations shown in FIGS. 5 to 7 are known. Hereinafter, the above conventional example will be explained with reference to FIGS. 6 and 7.

As shown in FIGS. 6 and 6, the prism group 101 is placed on the prism base plate 102, and after optical alignment is performed, the prism group 101 and the prism base plate 102 are bonded together using a resin adhesive 103.

This prism base plate 102 is fixed to a frame 104 of a color television camera. Entrance surface 105 of prism group 101
A lens system 106 is arranged on the side, and each exit surface 107, 108
, 109 side, solid-state image sensors 110, 111, 112 (or image pickup tubes) are fixed.

Next, the operation of the above conventional example will be explained. Lens system 10
Incident light 113 from 6 is transmitted to prism 114 of prisms 114, 115, and 116 constituting prism group 101.
The light of the blue component becomes reflected light 118 at the reflection surface 117 made of a Guiclock film that reflects the blue component, is totally reflected again at the entrance surface 105, and is emitted from the output surface 107 for 3 pages. , enters the solid-state image sensor 11o (or image pickup tube) to obtain a blue component image. Furthermore, the incident light 113 that has passed through the reflective surface 117 passes through the air gap 119 between the prisms 114 and 115, and enters the prism 115.
Reflective surface 12 made of a dichroic film that reflects red components
0, the red component light becomes reflected light 121, and the incident surface 122
It is totally reflected by the beam, exits from the output surface 108, and is emitted from the solid-state image sensor 11.
1 (or an image pickup tube) to obtain an image of the red component.

Finally, the incident light 113 that has passed through the reflective surface 120 passes through the prism 116 and exits from the output surface 109 to the solid-state image sensor 113.
(or an image pickup tube) to obtain an image of the green component.

A color image can be obtained by combining the signals of the solid-state image sensors 110, 111, and 112 (or image pickup tubes).

Problems to be Solved by the Invention However, with the above-mentioned conventional color separation optical system, there are major problems (1) that have not occurred in systems that use image pickup tubes even in conventionally used low-resolution cameras and high-resolution cameras. However, a problem arises when solid-state image sensors 110, 111, and 112 are used.In other words, when the color separation optical system is affected by heat, each component of the color separation optical system undergoes thermal expansion. This causes a misregistration, which is a phenomenon in which the optical path of each channel shifts, and as a result, the resolution of the image deteriorates significantly.The main reasons for this are as follows:
The following three are mentioned.

(1) The optical path changes as the prisms 114 to 116 expand geometrically.

(2) Since the prism base plate 102 and the prisms 114 to 116 are bonded with the resin adhesive 103, the prisms 114 to 116 are displaced in arbitrary directions when thermal expansion occurs, and the environment returns to its original state. Even after that, the arrangement does not return to its original shape. One of the reasons for this is as follows. In the process of assembling the prism group 101, as shown in FIG.
The prisms 115 and 116 are bonded to each other with a resin adhesive 121, the prisms 114 and 115 are interposed with a spacer 123 for forming an air 6 page carriage 119, and the prisms 114 to 116 is bonded to the prism base plate 102 with a resin adhesive 103. In such an assembly process, the reference is the plane through which the light beam passes, so the prisms 114 to 116
The joint portion 124 to the prism base plate 102 is not flat. In other words, the joint portion 124 becomes uneven due to dimensional tolerances and geometric tolerances during manufacturing of the prisms 114 to 116. Conventionally, a structure has been adopted in which this unevenness is absorbed by the resin adhesive 103. When heat is applied to such a color separation optical system, when the structural resin adhesive 103 expands, the amount of expansion changes because the thickness of this layer is uneven, and as a result,
Each of the prisms 114 to 116 is deformed separately, for example, as shown by broken lines in FIG. Moreover, even when the original environment is returned, the resin adhesive 103 that has been deformed by -degree does not completely return to its original state, so the deformation remains.

(3) Since the prism base plate 102, the prism group 101, and the resin adhesive 103 have different thermal expansions, distortion occurs and misregistration occurs.

Page 6 Traditionally, these effects were ignored with low-resolution cameras, but they become a major problem with high-resolution cameras. ” Among the factors listed in 2, the first factor is that the image pickup tube or solid-state image pickup devices 110 to 112 are connected to the prism group 1.
This can be avoided to some extent by directly fixing it to the exit surface 10-109 of 01. The second and third factors are those that use an image pickup tube (such as the regular convoter control of a color camera described in NHK Technical Research, Vol. 36, No. 2, 1982). By projecting a chart on the screen, detecting the amount of registration deviation between each channel, and electrically correcting it, it is possible to maintain high-resolution image quality.

On the other hand, in recent years, the number of color cameras using solid-state image sensors 110 to 112 has increased;
Although the resolution of 112 is increasing, this solid-state image sensor 1
10 to 112, it is very difficult to perform electrical correction like the above-mentioned image pickup tube. As a result, the displacement force of -7 to the prisms 114 to 1167 directly leads to misregistration. Furthermore, since electrical correction is generally performed periodically, it is difficult to deal with misregistration during that time.

Therefore, the present invention can minimize changes in the shape of the blizzard due to thermal expansion and contraction, thereby preventing misregistration due to the influence of heat, and maintaining high resolution image quality. It is an object of the present invention to provide a color separation optical system that can reduce the number and amount of correction even in a camera having an electrical correction section.

Means for Solving the Problems and Technical Means of the present invention for solving the above problems is that the bonding surface of the prism group that divides the incident light into a plurality of optical paths and emits it is bonded to the prism base plate using a bonding agent. At the same time, the joint surfaces of each prism constituting the prism group are brought into contact with a plurality of height-adjustable protrusions provided on the prism base plate.

For production The effect of this technical means is as follows.

In other words, since the joint surfaces of each prism constituting the prism group are supported by contacting with a plurality of height-adjustable protrusions on the prism base plate, the positional relationship of the prisms can be easily controlled against the influence of heat. can be prevented from changing. Therefore, it is possible to suppress the phenomenon in which the optical axes of the respective lights incident on the image pickup tube or solid-state image sensor move disparately between each channel, thereby minimizing misregistration, thereby achieving high-resolution image quality. It is also possible to reduce the number and amount of correction even in cameras that have an electrical correction section.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

1 to 4 show a color separation optical system according to an embodiment of the present invention, FIG. 1 is a perspective view, FIG. 2 is a plan view, FIG. 3 is a perspective view of the main part, and FIG. FIG. 9 is a cross-sectional view of the main part.

1 to 4, 1 is a prism group, 2 is a prism base plate. Prism group 1 is composed of prisms 3, 4, and 5, and an air gear knob 6 is located between prisms 3 and 4.
A spacer 7 is inserted to form a spacer. These prisms 3, 4, 5 are arranged with the light passing plane as a reference, and are bonded to the prism base plate 2 with a bonding agent 11 made of resin adhesive or the like. On the other hand, the prism base plate 2 has a plurality of pieces (three pieces each in the illustrated example) for each prism 3.4.5.
, a screw 22 is provided as a height-adjustable protrusion, the joint surface 1o of each prism 3.4.5 is brought into contact with the tip of the screw 22, and the outer edge of the joint surface 10 of each prism 3.4.6 is are supported at uniform positions at the vertices of the triangle. The prism base plate 2 is fixed to the frame 12 of the color camera, and the lens system 14 is arranged on the entrance surface 13 side of the prism group 1.
Image pickup tubes or solid-state image sensors 1B, 19, and 20 are arranged on each exit surface 15, 16, and 17 side of the prism group 1.

Next, the operation of the above embodiment will be explained. In the diagram on page 210, the incident light 21 from the lens system 14 is reflected by the prism 3 of the prisms 3.4.5 constituting the rhythm group 1.
The light is incident on the incident surface 13 of . This is color-separated by the reflective surfaces 22, 23, outputted to each output surface 16, 16, 17, and incident on each solid-state image sensor 18, 19, 20 (or image pickup tube), and the signals of each channel are combined. A color image can be obtained.

If thermal fluctuation occurs in the color separation optical system, the stress will be reduced because the joint surfaces 10 of each prism 3, 4, 5 are supported by the screws 22 at three equal positions on the outer edge as described above. Since it occurs uniformly on the surface 1o, it is possible to prevent the prism 3.4.5 from being deformed apart due to thermal expansion and contraction as in the conventional case. Therefore, it is possible to suppress deviations in image registration.

In addition, in the above embodiment, the screw 22 is attached to each prism 3.4,
Three prisms are used for each prism.
As long as the bonding surface 10 of 4.5 can be stably maintained, the number may be greater than this. 11. Screws other than 22 may be used as long as they are adjustable.

Further, although the prism base plate 2 is bonded to only one side of the prism group 1, it may be bonded so as to press the prism group 1 from both sides. Furthermore, if the prism 3.4.5 (e.

Effects of the Invention As described above, according to the present invention, the bonding surface of the prism group is bonded to the prism base plate using a bonding agent, and the height of the bonding surface of each prism constituting the prism group can be adjusted to the prism base plate. Since the prisms are brought into contact with a plurality of protrusions provided on the prisms, it is possible to prevent each prism from fluctuating randomly due to thermal fluctuations, and to suppress the occurrence of misregistration. Therefore, high quality images can be maintained, and even in cameras having an electrical correction section, the number and amount of correction can be reduced.

[Brief explanation of the drawing]

1 to 4 show a color separation optical system in an embodiment of the present invention, FIG. 1 is a perspective view, FIG. 2 is a plan view, FIG. 3 is a perspective view of the main part, and FIG. 5 to 7 show a conventional color separation optical system, FIG. 5 is a perspective view, FIG. 6 is a plan view, and FIG. 7 is a joint between a prism group and a prism base plate. FIG. 1... Prism group, 2... Prism base plate, 3-5.
...Prism, 18-20...Solid-state image sensor, 22...
- Screw (protrusion). Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4 Figure 5 776

Claims (2)

[Claims] (1) The bonding surface of the prism group that divides incident light into multiple optical paths and emits it is bonded to the prism base plate with a bonding agent, and the bonding surface of each prism that makes up the prism group is at a height above the prism base plate. A color separation optical system characterized by being brought into contact with a plurality of adjustable protrusions. (2) The color separation optical system according to claim 1, wherein the prisms constituting the prism group are bonded together at a surface through which incident light passes.