JPH06230218A - Quartz optical filter - Google Patents

Abstract

PURPOSE:To enable high precision efficient assembling and to improve productivity by bonding a pair of quartz plates to both optical principal faces of a color correction glass in one body and then carrying out cutting into separate filters. CONSTITUTION:A color correction glass 1 is an IR cutting filter molded in a disk shape. Quartz double-refractive plates 2 of the almost same size are stuck to both optical principal faces of the glass 1 so that the optical axes deviates from each other, e.g. by 45 deg.. Antireflection films 3 are formed on the outsides of the double-refractive plates 2, e.g. by coating with thin films of magnesium fluoride. An adhesive is applied to the double-refractive plates 2, the color correction glass 1 is held between the plates 2 and they are bonded in one body. Cutting is then carried out along a prescribed cutting line and the objective optical filters are obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal optical filter used in electronic optical equipment such as a video camera.

[0002]

2. Description of the Related Art Conventionally, in an electro-optical device such as a video camera or an electronic still camera, for example, a quartz optical filter is used in an optical system in order to prevent reflection of an incident light ray and perform color correction. There is. As such a crystal optical filter, for example, there is one in which crystal plates are provided on both main surfaces of a color correction filter for absorbing infrared rays. Then, on the surface of the crystal plate, magnesium fluoride (M
A thin film of gF2), silicon oxide (SiO2) or the like is formed and bonded together. In the case of manufacturing such a crystal optical filter, for example, a crystal plate having a thickness of about 1 mm is formed into a square of about 10 mm square, an antireflection film is vapor-deposited on the plate surface, and the plate is attached to both side plate surfaces of the color correction glass. I am trying.

However, in such a structure, it is necessary that the optical axes of the crystal plates differ from each other by a predetermined angle, for example, 45 °, and two types of crystal plates must be prepared. Thus, a quartz plate is made of, for example, an artificial quartz crystal.
Each piece is cut out into a predetermined shape, the outer shape is formed, and the surface is mirror-finished by polishing. Therefore, for example, when the outer shape of the crystal optical filter is rectangular, it is necessary to prepare two kinds of crystal plates so that the optical axes of the two crystal plates are different by 45 ° when assembled, and the cost is also increased. There was a problem that it became extremely high. Further, since such a crystal plate is small in shape and thin in thickness, the work of bonding is troublesome, and there is a problem that it is difficult to improve the accuracy of assembly.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a crystal optical filter which can be assembled with high precision and efficiency and can remarkably enhance productivity. It is intended.

[0005]

According to the present invention, the optical axes of a pair of crystal plates coated with an antireflection film on both optical principal surfaces of a color correction glass are shifted 45 ° from each other, and are sandwiched and bonded together. It is characterized by being cut into filters.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the perspective view shown in FIG. In the figure, reference numeral 1 is a color correction glass, for example, an infrared cut filter for blocking the passage of infrared rays formed in a disk shape having a diameter of 40 mm. A crystal birefringent plate 2 having substantially the same size is attached to both optical principal surfaces of the color correction glass 1. The outer surface of each crystal birefringent plate 2 is coated with, for example, a thin film of magnesium cuside (MgF2) to form an antireflection film 3
Is formed. Then, an adhesive is applied to the quartz crystal birefringent plate 2 so that the color correction glass 1 is sandwiched from both sides and integrally bonded. The adhesive used to bond the crystal birefringent plate 2 is preferably a polybutadiene-based or epoxy-based adhesive that can provide strong adhesive strength.

After the color correction glass 1 and the crystal birefringent plate 2 are integrally bonded, they are individually cut along a cutting line 4 as shown in FIG. An optical filter as shown in is obtained. In addition, when cutting such a crystal plate,
For example, a peripheral blade, a wire saw, a blade saw, or other appropriate device can be used. By doing so, for example, 12 optical filters each having a diameter of 40 mm and a size of 7 mm × 8 mm can be efficiently obtained.

With such a structure, since the quartz birefringent plate is attached to the relatively large disk-shaped color correction filter for cutting, the productivity can be remarkably increased. The manufacturing cost can be reduced by about 30% as compared with the case of assembling the individual members. Further, since a crystal-shaped birefringent plate having a relatively large diameter is attached, for example, by marking a mark in a predetermined axial direction of the crystal birefringent plate, the direction of the optical axis can be accurately moved by a predetermined angle. Can be different. Therefore, there is no need to prepare two types of crystal birefringent plates having different optical axis directions, and there is an advantage that only one type of crystal birefringent plate is required.

Further, since the shape of the crystal optical filter is determined at the time of cutting, it is possible to flexibly cope with various shapes of the crystal optical filter, and there is an advantage that the shape can be easily changed. Therefore, as compared with the conventional case where a quartz plate is cut into individual shapes, jigs and tools for outer shape processing, polishing processing, etc. are not required, which can contribute to cost reduction. Furthermore, the raw material quartz crystal may be of a certain size, which has the advantage of facilitating supply and management of the raw material. Further, when the crystal birefringent plate is attached to the color correction glass, the size is relatively large, workability is good, and accurate assembling work can be performed to improve productivity.

[0010]

As described in detail above, according to the present invention, it is possible to dramatically improve the productivity, thereby reducing the cost of the product, and to obtain a crystal of high quality and good optical performance. An optical filter can be provided.

[0011]

[Brief description of drawings]

FIG. 1 is an assembly perspective view showing a state during assembly of an embodiment of the present invention.

FIG. 2 is a plan view showing a cutting line according to an embodiment of the present invention.

FIG. 3 is a perspective view showing an optical filter of the present invention.

[Explanation of symbols]

 1 Color correction filter 2 Crystal birefringent plate 3 Antireflection film 4 Cutting line

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[Procedure amendment]

[Submission date] May 26, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Full text of column of detailed explanation of invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crystal optical filter used in electronic optical equipment such as a video camera.

[0002]

2. Description of the Related Art Conventionally, in an electro-optical device such as a video camera or an electronic still camera, for example, a quartz optical filter is used in an optical system in order to prevent reflection of an incident light ray and perform color correction. There is. As such a crystal optical filter, for example, there is one in which crystal plates are provided on both main surfaces of a color correction filter for absorbing infrared rays. Then, on the surface of the crystal plate, magnesium fluoride (M
A thin film of gF2), silicon oxide (SiO2) or the like is formed and integrally bonded. In the case of manufacturing such a crystal optical filter, for example, a crystal plate having a thickness of about 1 mm is formed into a square of about 10 mm square, an antireflection film is vapor-deposited on the plate surface, and the plate is attached to both side plate surfaces of the color correction glass. I am trying.

However, in such a structure, it is necessary that the optical axes of the crystal plates differ from each other by a predetermined angle, for example, 45 °, and two types of crystal plates must be prepared. Thus, a quartz plate is made of, for example, an artificial quartz crystal.
Each piece is cut out into a predetermined shape, the outer shape is formed, and the surface is mirror-finished by polishing. Therefore, for example, when the outer shape of the crystal optical filter is rectangular, it is necessary to prepare two kinds of crystal plates so that the optical axes of the two crystal plates are different from each other by 45 ° when assembled, and the cost is also increased. There was a problem that it became extremely high. Further, since such a crystal plate is small in shape and thin in thickness, the work of bonding is troublesome, and there is a problem that it is difficult to improve the accuracy of assembly.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a crystal optical filter which can be assembled with high precision and efficiency and can remarkably enhance productivity. It is intended.

[0005]

According to the present invention, the optical axes of a pair of crystal plates coated with an antireflection film on both optical principal surfaces of a color correction glass are offset from each other by a predetermined angle and are sandwiched and bonded together. It is characterized by being cut into a filter of.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the perspective view shown in FIG. In the figure, reference numeral 1 is a color correction glass, for example, an infrared cut filter for blocking the passage of infrared rays formed in a disk shape having a diameter of 40 mm. Then, a crystal birefringent plate 2 having substantially the same size is attached to both optical main surfaces of the color correction glass 1 with their optical axes displaced by 45 ° , for example . Note the outer surface of each quartz birefringent plate 2 to form an antireflection film 3, for example by coding a thin film of full tree of magnesium (MgF2). Then, an adhesive is applied to the quartz crystal birefringent plate 2 so that the color correction glass 1 is sandwiched from both sides and integrally bonded.

The adhesive used to bond the quartz crystal birefringent plate 2 is preferably a polybutadiene-based or epoxy-based adhesive that can obtain a strong adhesive strength. In addition, each crystal birefringent plate 2 is a plurality of water
The crystal plates should be stacked with their optical axes aligned.
Good. If you do this, the function of the crystal birefringent plate
It can be further increased.

After the color correction glass 1 and the crystal birefringent plate 2 are integrally bonded, they are individually cut along a cutting line 4 as shown in FIG. An optical filter as shown in is obtained. In addition, when cutting such a crystal plate,
For example, a peripheral blade, a wire saw, a blade saw, or other appropriate device can be used. By doing so, for example, 12 optical filters each having a diameter of 40 mm and a size of 7 mm × 8 mm can be efficiently obtained.

With such a construction, since a quartz birefringent plate is attached to a relatively large disc-shaped color correction filter and is cut, the productivity can be remarkably enhanced. The manufacturing cost can be reduced by about 30% as compared with the case of assembling the individual members. Further, since a crystal-shaped birefringent plate having a relatively large diameter is attached, for example, by marking a mark in a predetermined axial direction of the crystal birefringent plate, the direction of the optical axis can be accurately moved by a predetermined angle. Can be different. Therefore, there is no need to prepare two types of crystal birefringent plates having different optical axis directions, and there is an advantage that only one type of crystal birefringent plate is required.

Further, since the shape of the crystal optical filter is determined at the time of cutting, there is an advantage that various shapes of the crystal optical filter can be flexibly dealt with and the shape can be easily changed. Therefore, as compared with the conventional case where a quartz plate is cut into individual shapes, jigs and tools for outer shape processing, polishing processing, etc. are not required, which can contribute to cost reduction. Furthermore, the raw material quartz crystal may be of a certain size, which has the advantage of facilitating supply and management of the raw material. Further, when the crystal birefringent plate is attached to the color correction glass, the size is relatively large, workability is good, and accurate assembling work can be performed to improve productivity.

The present invention is not limited to the above embodiment.
Instead of, for example, crystal birefringence on both sides of the color-correcting glass
When the optical axis of the plate is shifted by a specified angle, for example, the wavelength
It may be optically realized by using a plate or the like. Also
This filter has an optical glass that corrects the optical path length of the optical system.
Etc. may be incorporated together.

[0012]

As described in detail above, according to the present invention, it is possible to dramatically improve the productivity, thereby reducing the cost of the product, and to obtain a crystal of high quality and good optical performance. An optical filter can be provided.

Claims (1)

[Claims] 1. A pair of crystal plates coated with an antireflection film on both optical principal surfaces of a color-correcting glass are offset by a predetermined angle from each other, sandwiched, and bonded integrally to be cut into individual filters. Quartz optical filter.