JPH0143690Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a beam splitter positioning device.

As is well known, a beam splitter splits an incident light beam into two or more in an imaging device, and is capable of transmitting and reflecting light.
In order for the light transmitted and reflected by this beam splitter (especially reflected light) to proceed along a predetermined optical system, the beam splitter must be positioned at a predetermined position and in any direction in space. Correct positioning in the condition becomes essential.

To do this, conventionally, a recess with a shape corresponding to the splitter is formed in the beam splitter holding member, and the beam splitter is inserted into the recess, but the beam splitter is held as described above. In order to do this, it is necessary to process the inner surface of the recess with high precision, and the holding member also requires a hole for light to pass through, and it is not easy to achieve such processing at low cost.

Although elastic metal members are also used to hold the beam splitter in position, two or more metal members are usually used to prevent the beam splitter from shifting in any of the x, y, or z axes. members are used. In this case as well, considerable difficulty is involved in properly processing and attaching the metal members.

The present invention follows the latter concept, and aims to provide a beam splitter positioning device that is easy to process and install, and can correctly position and hold a beam splitter in a predetermined position and state.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 1, on the optical axis O ₁ of the imaging system, there is a focusing lens 1 for focusing, a pair of movable lenses 2 and 3 for zooming, a beam splitter 20 for splitting incident light, and a focusing lens 1 for focusing. A master lens 4 and an imaging surface 5 for the image are arranged. Needless to say, the imaging surface 5 is an imaging surface of a film, a photographing tube, an imaging device, or the like. Above optical axis O ₁
A reflector 7, a focusing plate 8, a relay lens 9, and an eyepiece 10 are arranged on the optical axis O ₂ of the finder system attached to the camera, and an imaging lens 6 is disposed between the beam splitter 20 and the reflector 7. is located. The beam splitter 20 transmits and reflects incident light in the right angle direction, and has a flat rectangular plate shape (rectangular parallelepiped) as a whole, as shown in FIGS. 2 to 4.

Two recesses 31 and 32 with different widths are continuously formed at a predetermined depth from the upper surface of the beam splitter holding member 30 (this is provided, for example, at a fixed part of the camera body). recess 31
is the other recess 32 on the front surface 30a of the holding member 30.
are open at the rear surface 30b. Recess 32
is for inserting the beam splitter 20, and the recess 31 is for light to pass through.

The recess 32 has a pair of side surfaces 32a parallel to the optical axis _O1 .
and 32b, a pair of rear surfaces 32 perpendicular to the optical axis O ₁
c and 32d, and a bottom surface 32e that is parallel to the optical axis _O1 and perpendicular to the side surfaces 32a, 32b and the rear surfaces 32c, 32d. Side surfaces 32a, 32b
The distance between the front surface 30b and the rear surfaces 32c and 32d is slightly smaller than the thickness of the beam splitter 20, and the distance between the top surface 30c and the bottom surface 32e is slightly larger than the width of the beam splitter 20. It is slightly higher than the height of ivy 20.

The holding member 40 is made of an elastic metal plate, and its overall size is approximately equal to that of the beam splitter 20. A circular hole 41 for subject light to pass through is provided in the center, protruding pieces 42a, 42b, and 42c are provided on both sides and the bottom, respectively, and a bent piece 43a bent at right angles is provided on the top and one side. , 43b and 43c. A circular hole 45 having a diameter considerably larger than the shaft diameter of the machine screw 44 is bored in each of the protruding pieces 42a to 42c.

In FIGS. 3 and 4, the holding member 40 has its bent pieces 43a and 43b abutted against the upper surface 20a of the beam splitter 20, its bent piece 43c abutted against the side surface 20b, and its front surface 40a abutted against the rear surface 20e. It is attached to the holding member 30 by machine screws 44 at the pieces 42a-42c. Here, the beam splitter 20 receives a downward force from the bending pieces 43a and 43b in the plane of FIG.
0c is brought into close contact with the bottom surface 32e of the recess 32, and its side surface 20d is brought into close contact with the side surface 32a of the recess 32 under the force of the bent piece 43c in the left direction in the plane of FIG. Due to the difference in level between the rear surface 30b of the holding member and the rear surface 20e of the splitter, the elastic force due to the tightening force of the machine screw 44 is transmitted to the splitter 20 through the contact between the front surface 40a of the holding member and the rear surface 20e of the splitter. The splitter 20 receives a force upward in the plane of the drawing, and its front surface 20f is brought into close contact with the rear surfaces 32c and 32d of the recess. During this installation, the holding member 40 is allowed to move downward and to the left in the plane of FIG. 4 through the circular hole 45 of the protruding piece for positioning. When the positioning is completed, the screws 44 are completely tightened.

In this way, the beam splitter 20 is positioned and held in the x-, y-, and z-axis directions by the holding member 40 and the recess 32, so that the incident light can be transmitted and reflected in a predetermined direction. Moreover, since the holding member 40 is formed by processing and molding a single metal plate, it can be manufactured at low cost.

In addition, a bent piece 43 protruding from the upper part of the presser member
There may be only one piece a, 43b, or on the contrary, there may be a plurality of bent pieces 43c protruding from the side. Further, in order to transmit the tightening force of the machine screw 44 to the splitter 20, the holding member 40 is formed so that the main body portion and the protruding pieces 42a, 42b on both sides are located in different planes, as shown in FIG. It's okay. in this case,
Rear surface 30b of the holding member and rear surface 20e of the splitter
There is no need for a step between the two.

As described above, according to the present invention, the beam splitter is accurately positioned and held in a predetermined position and state by the holding member, and this can be achieved at low cost.

[Brief explanation of the drawing]

Fig. 1 is an optical system diagram of a video camera, Fig. 2 is a perspective view showing an embodiment of the present invention, Figs.
The figures are the same plan view and front view, respectively.
The figure is a plan view showing another embodiment of the present invention. Explanation of symbols of main parts, 20... Beam splitter, 30... Holding member, 32... Recess, 32
a, 32b...side surface, 32c, 32d...rear surface,
32e...bottom surface, 40...pressing member, 42a, 4
2b, 42c...Protruding piece, 43a, 43b, 43
c...Bent piece.

Claims (1)

[Claims for Utility Model Registration] In a positioning device for positioning and fixing a rectangular parallelepiped beam splitter to a holding member using a holding member, the holding member includes two orthogonal grooves for positioning the beam splitter. a concave portion including a first, second and third reference plane; the pressing member is made of a flat elastic member;
a transparent portion formed approximately in the center thereof;
a threaded part for fixing the transparent part to the holding member so as to face the reference plane; and a threaded part bent so as to face the second and third reference planes respectively in the fixed state. first and second bent portions, the holding member is configured to move the beam splitter housed in the recess to the second and second bent portions by the first and second bent portions. The beam splitter is screwed onto the holding member by the threaded portion while being in pressure contact with the reference surfaces of No. 3, and the beam splitter is pressed against the first reference surface with the resulting elastic force, thereby causing the beam splitter to contact the first reference surface. A positioning device characterized in that the ivy is positioned and fixed to the holding member.