JPH0743617A - Optical member holding mechanism - Google Patents

Abstract

PURPOSE:To eliminate the need of adjusting the position of an optical member after the assembling is completed by constituting a member for holding the optical member which is arranged on the optical path of the afocal part of a reflecting telescope of silicon nitride. CONSTITUTION:A primary mirror 22 is provided with a parabolic reflection face fixed on a primary mirror holding member 23 attached to the trailing end part of a lens barrel 21. A spider 24 is attached with the afocal part which is positioned at the front part of the lens barrel 21 and constituted of the silicon nitride. A secondary mirror holding member 25 for holding a secondary mirror 26 on the central part 24a of the spider 24 is fixed by spacers 27a, 27b, 28b and 28c and nuts 29a, 29b and 29c, and also, the spider 24 is fixed on the attachment part 21a of the lens barrel 21 by bolts and nuts through the holes 24b formed on the outer peripheral part. Besides, light reflected from the secondary mirror 16 is made incident on an eyepiece 30 through a light transmissive part 21b of the lens barrel 21. By constituting the spider 24 of the silicon nitride in such a way, vibration-resistance becomes high and also deformation by temperature is reduced, so that the need of adjusting the position of the optical member is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical member holding mechanism applied to a reflecting telescope.

[0002]

2. Description of the Related Art An optical member holding mechanism in a conventional reflection telescope is shown in FIG. That is, the one shown in the figure is a Newton-type reflecting telescope, in which a barrel tip ring 2 is provided at a front end of a lens barrel 1 and a main mirror attachment ring 3 is provided at a rear end thereof. A primary mirror holding member 5 for holding 4 is attached. Further, a secondary mirror unit 6 is supported by a spider 7 composed of four beams behind the barrel tip ring 2, and the spider 7 is attached to the barrel 1 by four bolts 8 arranged in the circumferential direction.
Further, the support of the secondary mirror unit 6 to the spider 7 is supported by the screw 9 biased by the coil spring 10 and the four screws 11, and the position of the secondary mirror unit 6 is set at three points by the respective bolts 8, 9 and 11. It is adjustable with.

[0003]

In the reflection telescope of the above-mentioned conventional example, the optical axes of the primary mirror 4, the secondary mirror unit 6 and the eyepiece lens are easily displaced, and it is necessary to make adjustments for optical axis alignment from time to time. It was

The present invention has been made in view of the above-mentioned problems of the prior art, and an object thereof is to provide an optical member holding mechanism for a reflecting telescope or the like which does not require adjustment such as optical axis alignment.

[0005]

In order to achieve the above-mentioned object, the optical member holding mechanism of the present invention comprises a member for holding an optical member arranged in the optical path of the afocal portion of a reflecting telescope made of silicon nitride. It was done.

[0006]

In the optical holding mechanism having the above construction, the holding member for the optical member has high earthquake resistance and little temperature deformation, so that the position adjusting mechanism for the optical member is unnecessary.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a schematic cross-sectional view of a reflecting telescope using this embodiment, and FIG. 2 is an exploded perspective view of its main part. In the figure, 21 is a lens barrel, and 22 is a primary mirror having a parabolic reflection surface fixed to a primary mirror holding member 23 attached to the rear end of the lens barrel 21. A spider 24 is attached to the front afocal portion of the lens barrel 21 and is made of silicon nitride.
The spider 24 has a spacer 27 with a secondary mirror holding member 25 for holding the secondary mirror 26 at the central portion 24a.
bolts 28a, 28b, 2 via a, 27b, 27c
8c and nuts 29a, 29b, 29c, and fixed to the mounting portion 21a of the lens barrel 21 with bolts and nuts (not shown) at the positions of the holes 24b on the outer periphery thereof. Reference numeral 30 denotes an eyepiece lens, which is the light transmitting portion 2 of the lens barrel 21.
Reflected light from the secondary mirror 16 enters through 1b.

In this embodiment having the above construction, the spacers 27a, 27b and 27c are selected from various thicknesses and used in order to adjust the position and angle of the secondary mirror 26 during assembly. Further, the main causes of the misalignment of the axes of the optical elements of the reflecting telescope are vibration and temperature changes during transportation. Therefore, it is desirable that the material of the spider 24 has high rigidity and a small coefficient of linear expansion with temperature. Table 1 shows the characteristics of various materials.

[0009]

[Table 1]

As is clear from Table 1, silicon nitride has a longitudinal elastic modulus equal to that of beryllium, a linear expansion coefficient twice that of Invar, and exhibits characteristics similar to Invar near room temperature. Therefore, since the spider 24 is made of silicon nitride, it is not affected by vibrations or temperature changes, so that it is almost unnecessary to adjust the position of the secondary mirror 26.

[0011]

As described above, according to the present invention, since the holding member of the optical member is made of silicon nitride, the vibration resistance is increased and the deformation due to the temperature is reduced, and the position adjustment of the optical member is not necessary. There is an effect suitable for supporting an optical member such as a telescope.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a reflecting telescope having an optical member holding mechanism according to an embodiment of the present invention.

FIG. 2 is an exploded enlarged perspective view of a main part thereof.

FIG. 3 is a cross-sectional view of a reflection telescope having a conventional optical member holding mechanism.

[Explanation of symbols]

21 .. Lens barrel, 22 .. primary mirror, 23 .. primary mirror holding member,
24 ... Spider, 25 ... Secondary mirror holding member, 26 ...
Secondary mirrors, 27a, 27b, 27c ... Spacers, 28a,
28b, 28c ··· bolt, 29a, 29b, 29c ·
・ Nut, 30 ・ ・ Eyepiece.

Claims (1)

[Claims] 1. An optical member holding mechanism, wherein a member for holding an optical member arranged in an optical path of an afocal portion of a reflecting telescope is made of silicon nitride.