Supports – Mirror or picture type – Bracket
Reexamination Certificate
2000-09-29
2001-11-27
Ramirez, Ramon O. (Department: 3632)
Supports
Mirror or picture type
Bracket
C248S550000
Reexamination Certificate
active
06322037
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
This invention relates to a moving mirror support device for use in, for example, photo-interferometers, and more particularly, to an improvement therein for improving operation thereof.
2. Description of the Prior Art
In spectral analyzers or various measuring instruments using photo-interferometers, moving accuracy of the order of &mgr;m is required of the moving mirror support device. However, if such instruments are used at a plant site, there is the problem of inability to attain high accuracy of measurement due to various environmental influences, such as vibration. In order to solve this problem, in the prior art, the rigidity of a moving mirror support device in directions other than the moving direction thereof was enhanced by arranging a pair of leaf springs to be parallel to each other.
FIG. 1
shows a Michelson interferometer, which is commonly used as a spectrometer in a spectral analyzer, wherein a light beam from light source
1
is changed to a parallel light by collimating lens
2
, then divided into two directions with beam splitter
3
. Moving mirror
4
and fixed mirror
5
return each light beam back to beam splitter
3
in opposite directions, and the return light beams are superimposed on beam splitter
3
. The physical properties of the measured object (not shown) are measured by using the optical interference generated by the superimposed light beams.
FIG.
2
(
a
) shows a conventional support device for a moving mirror used in such an interferometer, wherein moving mirror
4
is suspended from an upper position by two leaf springs
11
mounted on base
10
parallel to each other. Suspension by two leaf springs can suppress rotational motion generated when the moving mirror
4
is operated. If such an interferometer is used in a spectral analyzer, the moving mirror is driven transversely by a voice coil motor (not shown) about 0.3 mm and at 8 Hz. In such case, it is necessary to increase the amplitude (i.e. movement in the transverse direction) of the moving mirror in order to improve the resolution of the analyzer. However, by increasing the amplitude of the moving mirror
4
, deformation of the two leaf springs
11
becomes large, as shown in FIG.
2
(
b
), and the moving mirror is displaced transversely and longitudinally. Thus, the problem of longitudinal displacement arises and the optical axis of the return light will be shifted.
SUMMARY OF THE INVENTION
Accordingly, an object of the invention is to solve the foregoing and other problems, disadvantages and deficiencies of the prior art.
Another object is to provide a moving mirror support device, such as used in photo-interferometers, that has no longitudinal displacement when the transverse amplitude is increased.
The foregoing and other objects are attained by the invention which encompasses a moving mirror support device that has a plurality of first leaf springs arranged in parallel and held at a predetermined distance, one end of each leaf spring being fixed to a base; a coupling plate fixed to other ends of the first leaf springs; and a plurality of second leaf springs, each being arranged in parallel with each of the first leaf springs, one end of each being fixed to the coupling plate and the other end being fixed to the moving mirror.
Advantageously, the invention device eliminates displacement of the moving mirror in the longitudinal direction even when the transverse direction amplitude is increased.
In another embodiment, a damper is further provided to regulate the movement of the coupling plate, thereby enabling increased stability of the moving mirror.
In a further embodiment, control devices are added which control vibrations of the coupling plate based on signals from a position detecting device that senses displacement of the coupling plate and/or moving mirror. These added features further increase the stability of the moving mirror.
REFERENCES:
patent: 5505282 (1996-04-01), Olgac
patent: 40 279 889 A (1992-10-01), None
patent: 02000 111311 A (2000-04-01), None
Hayashi Hisanori
Isozaki Katsumi
Nanko Tomoaki
Otsubo Minoru
Kojima Moonray
Ramirez Ramon O.
Yokogawa Electric Corporation
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