JPH0755528Y2 - Spectral prism block - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a prism block in which a spectral prism formed by combining a plurality of prisms is adhered and fixed to a support base. For example, a plurality of image sensors are used. It is used for a color image pickup device for performing color image pickup.

[Outline of device]

According to the present invention, in a spectroscopic prism block in which a spectroscopic prism configured by combining a plurality of prisms is adhered and fixed to one side surface of a support base, a ceramic support substrate having a coefficient of thermal expansion substantially equal to that of the prism is used. The base is configured so that the female screw is stored in a state in which it is locked in the recess provided on one side of the support base, and the mounting screw that is inserted from the other side of the support base is screwed into the female screw for mounting. By fixing the spectroscopic prism block to the base, it is possible to prevent the adhesive strength between the spectroscopic prism and the support base from deteriorating, and it is possible to suppress the registration error and the fluctuation of the spectral characteristics due to temperature changes. Is designed to be inexpensive.

[Conventional technology]

Generally, in a color image pickup device, image pickup light from a lens is separated into a plurality of color components by a color separation system, that is, a red component, a green component,
And the blue component are separated into three colors, and the image of the subject of each color component is separated into each image pickup tube or charge coupled device (CCD: Charge Coupled Device).
A standard color television signal of the NTSC system is formed and output from each imaged output obtained by imaging with an image sensor such as Device).

As described above, as a color separation system that separates the imaging light from the lens into each color component, a spectral prism formed by combining a plurality of prisms, a so-called color separation prism is used. The color separation prism is adhered and fixed to one side surface of a support base made of, for example, an aluminum die cast to form a spectral prism block.

In a color imaging device using a plurality of image sensors, each image sensor is adjusted with high positional accuracy, for example, on the order of 1 μm, with respect to each emission surface of light of each color component obtained by the color separation prism, and each image sensor is adjusted. The subject images of the respective color components to be picked up are superimposed, that is, they are attached in a state where the registration adjustment is accurately performed.

FIG. 3 is a plan view showing a part of a video camera using such a conventional spectral prism block, and FIG. 4 is a side view showing the spectral prism. The support base and the mounting base in FIG. 4 are shown by a chain double-dashed line.

In these drawings, reference numeral 1 denotes a spectroscopic prism block, which is composed of a spectroscopic prism 2 and a support base 4 for adhering and fixing one side surface of the spectroscopic prism 2.

The spectral prism 2 is composed of a red prism 3R, a green prism 3G, and a blue prism 3B. A gap of 0.03 mm, for example, is provided between the prisms 3R and 3B in order to totally reflect red and blue, and the gap other than the one side surface to be bonded to the support base 4 is sealed with an adhesive or the like. At the same time, the other side is coated to prevent irregular reflection of light.

The support base 4 has a coefficient of thermal expansion close to that of the prisms 3R, 3G, 3B. For example, it is made of aluminum, stainless steel, titanium, or the like.

5R, 5G, 5B is a holding component attached to each exit surface of the prism 3R, 3G, 3B, 6R, 6G, 6B shows a solid-state image sensor consisting of CCD, the holding component 5R, 5G, 5B registration It is fixed after adjustment.

8 is a mounting base on which the spectral prism 2 is fixed by mounting screws 7, 9 is a housing to which the mounting base 8 is mounted,
Reference numeral 10 denotes a lens mount fixed to the front of the housing 9, to which a lens (not shown) is attached.

The conventional spectral prism block 1 configured as described above
Is to obtain the NSTC standard color television signal from the image pickup output obtained by each of the solid-state image pickup devices 6R, 6G, and 6B by splitting the image pickup light from the lens (not shown) by the spectral prism 2.

However, since the spectral prism 2 is adhesively fixed to the metal support base 4, the support base 4 and the prisms 3R, 3G,
Since there is a difference in the coefficient of thermal expansion with 3B, the adhesive part peels off due to temperature stress of about -20 to 60 ° C, and it becomes unusable, and the support base 4 and prisms 3R, 3G, 3B There is a problem in that a registration error occurs due to the difference in expansion between the two and the spectral characteristics change.

Therefore, in order to solve the above-mentioned problems, the present applicant has a spectral prism block (Japanese Utility Model Application No. 60-064790) in which the support base is made of a material having a coefficient of thermal expansion substantially the same as that of the prism. ) Proposed.

In the spectroscopic prism block previously proposed by the applicant, the support base is made of, for example, ceramic so that the thermal expansion coefficients of the support base and the prism are substantially equal to each other.
This is a solution to the above-mentioned problems.

[Problems to be solved by the invention]

However, in the spectral prism block previously proposed by the present applicant, since the support base is made of ceramic, it is difficult to provide the support base with screw holes having a fine pitch or mold the female screw. Therefore, there is a problem that it becomes difficult to mechanically attach the spectral prism block to the attachment base.

This invention provides a spectral prism block that solves the above-mentioned problems.

[Means for solving problems]

The spectroscopic prism block of the present invention comprises a support base made of ceramic having a coefficient of thermal expansion substantially equal to that of the prism, and a female screw is held in a recess provided on one side of the support base while being prevented from rotating. It is housed and a spectral prism is adhered and fixed to one side of the support base.

[Action]

In the spectroscopic prism block of the present invention, the spectroscopic prism block can be mechanically attached to the mounting base by screwing a mounting screw inserted from the other side of the support base into a female screw.

〔Example〕

FIG. 1 is an exploded perspective view showing an embodiment of the spectroscopic prism block of the present invention, and FIG. 2 is an enlarged sectional view showing a mounting state of the spectroscopic prism block. The same parts as those in FIGS. 3 and 4 are the same. The reference numeral is attached.

In these drawings, reference numeral 11 denotes a spectroscopic prism block, which is composed of the spectroscopic prism 2, a support base 12, a female screw 16, and a seal 18. The support base 12 is made of a ceramic having a coefficient of thermal expansion that is substantially the same as the coefficient of thermal expansion of the prisms 3R, 3G, and 3B that form the spectral prism 2, and one side surface to which the spectral prism 2 is bonded has a hexagonal shape. A recess 13 and a step 14 having a shape slightly larger than the recess 13 are provided, and a through hole 15 communicating with the recess 13 is provided from the other side surface side.

The female screw 16 has a hexagonal shape, is in a rotation-stopped state for being inserted into the recess 13, and is provided with a projecting portion 17 that is inserted into the through hole 15. The projecting portion 17 also has a screw thread. It is provided.

The seal 18 is adhered to the stepped portion 14 of the support base 12 to position the female screw 16 in the recess 13, and is black.

A female screw 16 is formed in the recess 13 of the support base 12 configured as described above.
Is inserted, and the seal 18 is attached to the step portion 14 with the protruding portion 17 positioned in the through hole 15, and the spectral prism 2 is supported on the support base 12.
The spectroscopic prism block 11 is configured by adhesively fixing it to one side surface.

The spectroscopic prism block 11 of the present invention configured in this way
Can be mechanically attached to the mounting base 8 by screwing the mounting screw 7 penetrating the mounting base 8 onto the female screw 16. Since the support base 12 is made of ceramic, the support base 12
Becomes cheaper, and its coefficient of thermal expansion is reduced to prisms 3R, 3G,
Since it can be the same as 3B, the same effect as the spectral prism block previously proposed by the present applicant, that is, the deterioration of the adhesive strength between the spectral prism 2 and the support base 12 due to temperature stress can be prevented, and the hard type By using this adhesive, the adhesive strength between the spectral prism 2 and the support base 12 can be improved, and at the same time, a registration error due to a temperature change and a variation in the spectral characteristic can be suppressed to be small.

Further, since the support base 12 is black and the female screw 16 is covered with the seal 18, it is possible to prevent diffuse reflection of light of the spectral prism 2, and dust and the like enter the side of the spectral prism 2 through the screw hole. Can be prevented.

Further, since the female screw 16 is provided with the projecting portion 17 and the projecting portion 17 is also provided with the screw thread, the effective thread portion of the female screw 16 that engages with the screw 7 can be large, and therefore the female screw 16 is not provided with the projecting portion 17. The support base 12 can be made thinner than in the case.

In the embodiment described above, the female screw 16 provided with the protrusion 17 is used, but it goes without saying that a normal female screw not provided with the protrusion 17 may be used.

[Effect of device]

As described above, the spectral prism block of the present invention comprises a support base made of ceramic having a coefficient of thermal expansion substantially equal to that of the prism, and is prevented from rotating in a recess provided on one side surface of the support base. The female screw is stored in this state, and the spectroscopic prism is adhesively fixed to one side of the support base.By attaching the mounting screw inserted from the other side of the support base to the female screw, The spectroscopic prism block can be attached mechanically. In particular, even when the support base is made of ceramic, it is not necessary to thread a support base that is difficult to process, so that the support base can be made thin and can be manufactured at low cost. And since the coefficient of thermal expansion can be made almost the same as that of the prism, deterioration of the adhesive strength between the spectral prism and the support base due to temperature stress can be prevented, and by using a hard type adhesive, The adhesive strength with the support base can be improved.

Further, there is an effect that it is possible to suppress the registration error and the fluctuation of the spectral characteristic due to the temperature change.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing an embodiment of the spectral prism block of the present invention, FIG. 2 is an enlarged sectional view showing a mounting state of the spectral prism block, and FIG. 3 is a video camera using the conventional spectral prism block. 4 is a plan view showing a part of FIG.
The figure is a side view showing the spectral prism. In the figure, 2 is a spectroscopic prism, 3R, 3G and 3B are prisms, 7 is a mounting screw, 8 is a mounting base, 11 is a spectroscopic prism block, 12
Is a support base, 13 is a recess, and 16 is a female screw.

Claims (1)

[Scope of utility model registration request] 1. A support base composed of a spectroscopic prism formed by combining a plurality of prisms and a ceramic having a coefficient of thermal expansion substantially the same as that of the prism, and the spectroscopic prism being adhered and fixed to one side surface. The base and a female screw housed in a recess provided on one side of the support base in a state of being prevented from rotating.A mounting screw inserted from the other side of the support base is screwed into the female screw. The spectroscopic prism block is characterized in that it can be fixed to the mounting base.