JPS58172604A - Holding device for optical system - Google Patents

Abstract

PURPOSE:To obtain a good picture quality in spite of a change in environmental temp. by joining a rigid plate-like base plate having a small coefft. of thermal expansion and an elastic and buckled plate-like movable plate having a large coefft. of thermal expansion in both end parts thereof and changing the buckling rate of the movable plate owing to a difference in thermal expansion and elongation or contraction with a change in temp. CONSTITUTION:When a change arises in environmental temp., a movable plates 2 elongates or contracts at a high rate than a base plate 1 on account of a difference in the coefft. of thermal expansion of the plate 1 and the coefft. of thermal expansion of the plate 2. The substrate 1 has higher rigidity than the plate 2; therefore, in the end, the difference in the rate of expansion or contraction is absorbed as a change in the buckling rate of the plate 2. The change in the buckling rate of the plate 2 is several tens times larger than the rate of expansion or contraction owing to the mere thermal expansion of the movable plate. If the plate 2 is provided on both sides of the plate 1, the bending force of the plate 1 occuring in the buckling of the plate 2 is offset and the ridigity required for the plate 1 is decreased. This device has the characteristic that the controlled variable of position is two-times larger as the plate 2 buckles at a two- times higher rate.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is an optical system including, for example, a plastic lens. The present invention relates to an optical system holding device that compensates by controlling the position of a surface.

Conventionally, plastic materials have a large coefficient of thermal expansion and a large change in refractive index due to temperature, so in optical systems that include plastic lenses made of plastic materials,
There was a problem in that the optical performance, especially the focal length, changed due to changes in the environmental temperature. Specifically, this refers to the object plane and lens system.

If each position of the image plane remains fixed, the focal length of the optical system will change due to changes in environmental temperature, and the image that should originally be formed will not be formed, making it impossible to obtain good image quality. The countermeasure is to change the object plane position or image plane position as the focal length changes.

Alternatively, the position of the lens system, or in the case of a lens system consisting of a plurality of lenses, the position of at least one lens in the lens system can be minutely controlled.

In an optical system that includes a glass lens made of plastic material, the optical performance depends on the object plane position, image plane position, or lens system.

Alternatively, it is important to control at least one lens in the lens system in response to temperature changes.

In the present invention, in the optical system as described above, VC is applied so that good image quality can be obtained even when the environmental temperature changes. The object of the present invention is to provide an optical system holding device that has a position control function based on temperature.

The present invention will now be described in detail with reference to the drawings.

FIG. 1 is a perspective view of one embodiment of the present invention, and FIG.
FIG. 2 is a side sectional view of FIG. 1; In those drawings V, a rigid strip-shaped base vi1 with a small coefficient of thermal expansion is a fixed frame 3V.
This joint surface, 6. , :: The movable plate 2 in the form of an elastic band with a fixed blade and a large coefficient of thermal expansion is connected to the movable frame 4 by the joint surface 7.
is fixed. The lens barrel 6 is fixed to a movable frame 4, and the movable frame 4 can freely slide on the fixed frame 3.
An example of position control of a lens system is shown. The substrate 1 and the buckled movable plate 2 are shown in the side sectional view in Fig. 3(,) and in Fig. 3().
As shown in the perspective view b), they are joined at a joint surface 9 with an extra space 8 created.

In the above configuration, when a change occurs in the environmental temperature, the amount of expansion and contraction of the movable plate 2 becomes larger than the amount of expansion and contraction of the substrate 1 due to the difference between the coefficient of thermal expansion of the substrate 1 and the coefficient of thermal expansion of the movable plate 2. ,
Furthermore, since the substrate 1 has higher rigidity than the movable plate 2, the difference in the amount of expansion and contraction is eventually absorbed as a change in the amount of buckling of the movable plate 20. This change in the amount of buckling of the movable plate 2 is several tens of times the amount of expansion and contraction due to thermal expansion of a single movable plate.

FIG. 4 is a perspective view showing a specific example of the support structure shown in FIG. 3. Stoppers 10 are provided at both ends of the substrate 1, and the movable plate 2 is fixed to both sides of the substrate 1 with a presser 11 and screws 12. By providing the 0T movable plates 2 on both sides of the substrate 1, the bending force of the substrate 1 due to buckling of the movable plate 20 is offset, and the rigidity required of the substrate 1 is reduced. Also,
Since the amount of buckling of the movable plate 2 is doubled, the amount of position control is also doubled.

FIG. 5 is a perspective view of a modification of the support structure of FIG. 4.

This is a simple V-shaped structure in which a stopper 10' having presser clasps 13 is provided at both ends of the board 1, and the movable plate 2 is fixed by the clasps 13V. The buckling of the movable plate 2 is different from the buckling of the movable plate shown in FIGS. 1 to 4, and is arcuate, but the position control function is the same.

6 and 7 show a perspective view and a plan view of an embodiment in which a plurality of the support structures shown in FIG. 6 are combined. That is, this means that multiple Nostochers 10 can be mounted on one substrate 1'.
' are provided at predetermined intervals, and a plurality of movable plates 2' are disposed between these stoppers 10' so as to be located on both sides of the substrate 1', and such supports and Two supporting structures are arranged side by side, namely, the movable plates 2' are connected to each other at the joint surface 14, the movable plate 2' and the fixed frame 3 are connected to the joint surface 6', and the movable plate 2' and the movable frame are connected to the joint surface 7'. 4 are joined to each other. With this structure, the buckling force of the movable plate 2' can be accumulated, and the driving force of the movable frame 4 can be increased. In addition, the movable plate 2
By accumulating the buckling amounts of ', the position control amount of the movable frame 4 can be increased. In this embodiment, the movable frame 4
It is shaped to fix the lens barrel, but it is a screen or a cathode ray tube.

Alternatively, the structure may be such that at least one lens is mounted on the image pickup tube or the lens system.

In addition, in FIGS. 6 and 7, the same effect as described above can be obtained even if the structure shown in FIG. 4 is used.

As described above, according to the present invention, optical performance changes t! due to changes in environmental temperature! It is possible to provide Ff with an optical system holding device that can compensate for changes in the focal length of the lens system.

[Brief explanation of drawings]

Figures 1 and 2 are a perspective view and a side sectional view showing an embodiment of the present invention, Figure 3 is a sectional view and a perspective view of essential parts of an example of a support structure used in the present invention 4 and 6 are perspective views showing another example of the vine support structure used in the present invention, and FIGS. 6 and 7 are a perspective view and a plan view of a specific embodiment of the present invention, respectively. . 111' 6, 8.6 substrate, 2.2', . 11. Mobile roots, 3. , 93° fixed frame, 4. . 009. Movable frame, 1o, 10'... Stone '9-111...
...presser, 13...0. Presser foot. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure J? I Figure 3 Figure 5

Claims (4)

[Claims] (1) A rigid plate-shaped substrate with a small coefficient of thermal expansion and an elastic buckled plate-shaped movable plate with a large coefficient of thermal expansion are joined at both ends. An optical system holding device characterized in that the optical position of the optical system is displaced in response to temperature changes by changing the amount of buckling of the movable plate. (2) The optical system holding device according to claim 1, wherein the substrate and the movable plate are joined by a stopper, a presser, and a screw provided on the substrate. (3) The optical system holding device according to claim 1, wherein the substrate and the movable plate are fixed by a stopper having a presser foot provided on the substrate. (4) The optical system holding device according to claim 1, characterized in that movable plates are provided on both sides of the substrate.