JPH03167516A - Device for damping reflection mirror - Google Patents

Abstract

PURPOSE:To satisfactorily effectively damp a reflection mirror without causing increase in its weight by providing amplifiers which receive outputs for detecting the vibration of the reflection mirror outputted from piezoelectric elements attached to the rear surface of the reflection mirror and supply reflection mirror damping outputs to the piezoelectric elements. CONSTITUTION:One or plural piezoelectric elements are attached to the rear surface of the reflection mirror, reflection mirror vibration signals outputted from this piezoelectric elements are inputted to the amplifier, and reflection mirror damping signals are inputted to the piezoelectric elements from this amplifier. The piezoelectric elements 3 are provided on plural parts, especially, stuck to a part where the quantity of change in vibration displacement in the intrinsic vibration mode of the reflection mirror 1 is maximum. The amplifiers 4 receive the outputs for detecting the vibration caused by the deformation of the reflecting mirror 1 from the piezoelectric elements 3 and supply the piezoelectric elements with the damping outputs at a prescribed level in a direction restricting the deformation. Thus, satisfactory damping effect can be obtained and the reflection mirror itself can be made reduced in weight.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a vibration damping device for a reflecting mirror used in a reflecting telescope, etc., which suppresses vibration of a reflecting mirror due to external disturbances such as wind. be.

[Conventional technology]

FIG. 2 is a sectional view showing a conventional vibration damping device for a reflecting mirror.
In the figure, reference numeral 1 denotes a reflecting mirror, which is made of a plated metal plate or the like. 2 is a viscoelastic material affixed to the back surface of the reflecting mirror 1, which acts as a viscoelastic composite structure to suppress deformation of the reflecting mirror ↓.

Next, the operation will be explained.5 Now, when the reflecting mirror 1 is deformed due to external disturbances such as wind, when used in a reflecting telescope, it causes displacement of the optical axis and deformation of the reflected image. However, since the reflecting mirror 1 is held by a viscoelastic material 2, even if the reflecting mirror 1 expands and contracts due to vibration, the strain energy of this expanding and contracting deformation is absorbed by the viscoelastic material 2, and the It acts to immediately suppress expansion and contraction.

[Problem to be solved by the invention]

Since the conventional vibration damping device for a reflecting mirror is constructed as described above, in order to obtain a sufficient damping effect, the viscoelastic material 2 is required to have a sufficient thickness, and therefore the weight including the reflecting mirror 1 is reduced. Applying this to a large reflecting telescope is not only extremely disadvantageous in terms of structure and economy, but also poses problems such as the inability to suppress minute deformations in a portion of the reflecting mirror 1. was there.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a vibration damping device for a reflecting mirror that can sufficiently effectively damp the vibrations of the reflecting mirror without causing an increase in weight. In addition, such a conventional reflector allocation device is described in "Noise Prevention Design and Simulation" by Shiraki, Applied Technology Publishing (published on April 18, 1987). A technique similar to P253 has been described.

[Means to solve the problem]

A vibration damping device for a reflecting mirror according to the present invention includes: attaching one or more piezoelectric elements to the back surface of a reflecting mirror provided in an optical device; inputting a vibration signal of the reflecting mirror outputted by the piezoelectric element to an amplifier; The vibration damping signal of the reflecting mirror is inputted from this amplifier to this piezoelectric element.

[Effect]

The piezoelectric element in the present invention detects the magnitude of deformation (vibration) of a deformed portion on a reflecting mirror and outputs a signal corresponding to this magnitude. Therefore, the amplifier receives this signal and outputs a corresponding piezoelectric element parking current, and applies a mechanical force to the deformed portion to suppress the deformation, thereby preventing deformation of the reflecting mirror due to disturbance.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, reference numeral 1 denotes a reflecting mirror, which is made of, for example, a plated metal plate. 3 is a piezoelectric element attached to the back surface of this reflecting mirror 1. Note that this piezoelectric element 3 is provided at a plurality of locations as shown in the figure, and in particular, the piezoelectric element 3 is provided at a plurality of locations as shown in the figure.
It is desirable to attach it to the area where the amount of change in vibration displacement of the natural vibration mode of is maximum. Reference numeral 4 denotes an amplifier which receives a vibration detection output from the piezoelectric element 3 due to the deformation of the reflecting mirror 1, and supplies the piezoelectric element 3 with a vibration damping output at a predetermined level in the direction of suppressing the deformation.

Next, the operation will be explained. First, while using the telescope,
A reflection of this! ! When mirror 1 vibrates due to external disturbances such as being exposed to wind, the front and back surfaces of reflector 1 are deformed by repeatedly expanding and contracting. Therefore, the piezoelectric element 3 generates an electromotive force according to this amount of deformation. Therefore, this power is amplified by amplifier 4, and a current is output in the direction of suppressing the deformation. Therefore, in response to this current, the piezoelectric element 3 generates a force in the direction opposite to the deformation of the reflecting mirror 1, and applies this force to the reflecting mirror 1.

That is, when the reflecting mirror 1 is extended, the piezoelectric element 3 deforms it in the direction of contraction, and it is reflected! ! When I1 contracts, the piezoelectric element 3 deforms it in the direction of extension. This deformation force suppresses vibrations of the reflecting mirror l due to disturbances.

In the above embodiment, the piezoelectric element 3 is provided with an amplifier 4, but the amplifier 4 may not be connected and the piezoelectric element 3 may be short-circuited. However, although this case is cheaper than the case where the amplifier 4 is provided, the damping effect is small.

〔Effect of the invention〕

As described above, according to the present invention, one or more piezoelectric elements are attached to the back surface of a reflecting mirror provided in an optical device,
The vibration signal of the reflecting mirror output from this piezoelectric element is input to an amplifier, and the amplifier inputs a damping signal of the reflecting mirror to this piezoelectric element, so the weight of the reflecting mirror itself can be reduced. Therefore, it becomes possible to use a reflecting mirror for a large-diameter telescope, and there is an effect that the vibration of such a reflecting mirror can be efficiently suppressed mainly in the portion where the rate of change of the vibration mode is large.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a vibration damping device for a reflecting mirror according to an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional damping device for a reflecting mirror. 1 is a reflector, 3 is a piezoelectric element, and 4 is an amplifier. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Figure 2 Procedural amendment (voluntary) 2. Name of the invention Reflector allocation device 3. Relationship with the case of the person making the amendment Patent Applicant Address 2-2-3 Marunouchi, Chiyoda-ku, Tokyo Name (601) Mitsubishi Electric Corporation Representative Moriya Shiki 4. Agent Postal code 105 Address
Column 6 of the detailed description of the invention in the specification No. 1-4 Nishi-Shinbashi, Minato-ku, Tokyo The description of contents of the sleeve is corrected as follows.

Claims (1)

[Claims] A reflecting mirror provided in an optical device, one or more piezoelectric elements attached to the back surface of this reflecting mirror, and receiving the vibration detection output of the reflecting mirror outputted by this piezoelectric element, A vibration damping device for a reflecting mirror, comprising an amplifier that supplies vibration damping output of the reflecting mirror.