JPS62131215A - Lens holder - Google Patents

Abstract

PURPOSE:To make fixing force constant in spite of temperature change and to prevent lenses from positional shift by inserting a press tool using a material having proper size to absorb a thermal expansion difference into a lens barrel and between a spacer and the lens. CONSTITUTION:The lenses 1 are inserted so as to be abutted on a step part of the lens barrel 2b and the annular spacer 3b for pressing the lenses 1 is also inserted. To fix the spacer 3b, the spherical press tool 5 consisting of a material with a thermal expansion factor for absorbing the thermal expansion difference of the lenses from the lens barrel 2b and the spacer 3b and having proper size is pressed against the spacer 3b, a pair of lenses 1 are combined through the spacer 3b in the axial direction and press force is applied by a press screw 4. Consequently, the lens positions of the combined lenses can be stably fixed in spite of temperature change.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a lens holding device, and particularly to an improvement in a lens holding structure that is stable against temperature changes.

[Background of the invention]

As described in Japanese Unexamined Patent Application Publication No. 57-34508, conventional devices use adhesives to compensate for the lack of force between the lens and the presser in the axial direction due to temperature changes, and the presser force in the radial direction. However, no consideration was given to actively maintaining stability against temperature changes.

Note that related devices of this type are disclosed in Japanese Patent Application Laid-open No. 58
-87505 publication is mentioned.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a structure that maintains the lens position in the axial and radial directions at all times and obtains stable aberrations even when the temperature changes.

[Summary of the invention]

In general, a lens holding device for a combination lens inserts a lens l into a lens barrel 2 shown in FIG. It is known that the lens is positioned by slightly moving it through a hole at a certain point, and then fixed using a retaining screw 4 and an adhesive.

As for the materials of these components, the lens barrel 2, spacer 3, and retainer screw 4 are generally made of metal, and the lens 1 is made of glass. A gap occurs due to the difference in thermal expansion at high temperatures, and the fixing force of the lens is insufficient.

The lens position is shifted. On the other hand, when the temperature is low, the fixing force increases, leading to worsening of various aberrations. The present invention is.

A holding device made of a material with appropriate dimensions that absorbs differences in thermal expansion is inserted between the lens barrel, spacer, and lens to maintain a constant fixing force even when the temperature changes, thereby preventing the lens from shifting. This makes it possible to improve the deterioration of various aberrations.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
Figure (a) shows a cross-sectional view of this embodiment.

The lens 1 is inserted so as to come into contact with the stepped portion of the lens barrel 2C,
An annular spacer 3b is inserted to hold down the lens 1. To fix this spacer 3b, the lens barrel 2b and spacer 3
A spherical presser 5 made of a material with a thermal expansion coefficient that absorbs the difference in thermal expansion between the lens 1 and the lens 1 and having an appropriate size is pressed, and a group of lenses is further combined in the axial direction, and a pressing force is applied by a presser screw 4. Regarding the radial direction, screw holes are machined in the lens barrel 2b,
It has a structure in which pushing force is applied by a set screw 6.

Figure 1(b) shows that when positioning the lens 1 by slightly moving it in the radial direction, a material with a thermal expansion coefficient of 1 is used between the lens barrel 2b and the lens 1 to absorb the difference in thermal expansion between the lens barrel 2b and the lens 1. It has a structure in which a spherical presser 5 of an appropriate size is pressed against it, and a pressing force is applied by a set screw 6 to fix it.

The shape of the presser 5 is not limited to a spherical shape, but may be a plate shape as long as it has a size that can absorb the difference in thermal expansion.

FIG. 3 shows a ZZ cross section of FIG. 1(a), and the presser is fixed at three points equally divided into three parts of the circumference to obtain a uniform fixing force. It has been experimentally confirmed that three or more locations are sufficient.

Figure 4 shows the relationship caused by the difference in thermal expansion due to temperature change. In the case of A and C in Figure 4, ff□X (αz-
cz,) Xto=QxIXαx, Xt, l.

Therefore, the relationship Qll　α2. α.

When is determined, Qx and αX□ can be selected based on the material and space of the presser. Similarly, in the case of Figure 4B, Qo× (α2−α3)×.

=Qx2Xα2Xt. -1-Qx, Xczx2Xt.

Therefore, Q. , α2. α□.

When Qx2 is determined (lx, and Qx2 are the material of the presser.

You can choose based on the space.

In the case of A in this embodiment, Q□=2.8. α2=23X L
When O-', α, = 8 X 10-', Qx, = 0.3, αx, = l 4 X I O-'. In this case, it turns out that resin such as PVC can be used as the presser material, and similarly in case of B, α. =1°4, a2
=23 X 10-”, a, =8 X I O-G, Q
x2" 0, 7, Q There is.

〔Effect of the invention〕

According to the present invention, since the lens position of the combined lens can be stably fixed against temperature changes, the movement of the lens with respect to the lens barrel can be suppressed even under vibration conditions, which is effective for improving vibration characteristics.

Furthermore, when finely adjusting the lens in the radial direction, it can be fixed at the same time as the adjustment, which has the effect of reducing the number of lenses to be worked on.

3 is a sectional view taken along the Z-Z line in FIG. 1, and FIG. 4 shows the position of the holding device to show the principle of absorbing the difference in expansion with the holding device. FIG.

1... Lens, 2... Lens barrel, 3... Spacer, 4...
- Holder screw, 5 - Holder, 6 - Set screw.

Figure 1 Figure 2 (α) (b) Figure 3 Figure 4 (A) (C) Display of 11G patent application No. 271451 filed in 1985, title of invention 11 cases by those who correct lens holding device Master Patent Applicant 21k 15101 2 Shares
Subject of person's amendment 1, "As shown in Figure 2" on page 2, line 12 of the specification is revised to "As shown in Figures 5I7I and 6." .

2. In the 11th line of page 3 of the specification, the phrase ``Figure 1 (a)'' is corrected to ``Figure 1 is''.

3. In the second line of page 4 of the specification, the phrase ``Figure 1 (b)'' is corrected to ``Figure 2 is''.

4. On page 4, line 10 of the specification [Figure 3 and Figure 1 (a)]
1F has been revised to read "Figure 7 and Figure 1."

5. In the 14th line of page 4, the statement ``Figure 11 shows U variation'' is corrected to ``Figures 8 to 10 show temperature change.''

6. On page 4, line 15, [A and CJ in Figure 4 are corrected to read ``Figures 8 and 10.''

do.

8. The statement "FIG. 1 is a sectional view of the present invention" in lines 6 to 11 of page 6 of the specification is amended as follows.

1 and 2 are cross-sectional views of a lens holding part of a combination lens according to an embodiment of the present invention, and FIGS.
The figure is a partially enlarged view of portions A and B in FIGS. 1 and 2.

FIGS. 5 and 6 are cross-sectional views of a lens holding portion of a combination lens in a conventional device. Figure 7 shows the Z-
FIGS. 8 to 10, which are Z sectional views, illustrate the principle of absorbing the difference in expansion in the presser.

Above Figure 1 Figure 2 Figure 3 Figure 4 - Figure Multicolor 5 Figure
No. 7 Sae] No. 7

Claims (1)

[Claims] 1. A cylindrical lens barrel with a step formed on the inner surface, a group of lenses provided so as to come into contact with the step inside the lens barrel, and a spacer that holds the lens inserted into the lens barrel inside the lens barrel. A lens holding device comprising: (1) a holding device that absorbs the difference in thermal expansion in the axial and radial directions; and a holding device that can be adjusted and fixed by the holding device.