JPH03240284A - Ring type laser device - Google Patents

Abstract

PURPOSE:To avoid a decrease in the property of a reflecting mirror by providing a controller for preventing adherence of getter medium evaporated and scattered from a getter to the mirror in the bottom of a containing recess for holding the getter. CONSTITUTION:In a ring type laser device, a conical protrusion 21 as a control ler is provided in the bottom 3a of a containing recess 3 for holding a getter 9. In this case, when the vertex angle of the protrusion 21 is A, the maximum diameter is C, the outer diameter of the getter 9 is D and the inner diameter is d, the diameter C is so set as to satisfy the relation of D>C>d. When it is so extended that an angle X from the top of the protrusion 21 to the exten sion line (l) of an imaginary line directed to the lower center becomes an angle equal to the angle A, a position where the interval of the line (l) becomes equal to the diameter D is B, and the getter 9 is disposed at the position B or a position between the position B and the bottom 3a of the recess 3. Thus, when the getter 9 is heated, the evaporated and scattered medium is not reflected in a direction for passing the inner part of the getter 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a ring-shaped laser device used in a ring laser gyro or the like.

(Prior art) For example, a ring laser device used in a ring laser gyro oscillates laser beams that travel in opposite directions within a closed annular optical path, and when the entire device rotates, the two laser beams are separated into two optical paths. A difference occurs (Sagnac effect), and this optical path difference causes a frequency difference between the two laser beams traveling in opposite directions. When these two laser beams are superimposed, interference fringes with a beat frequency are formed, which can be used to measure the rotational angular velocity.

Conventionally, such a ring-type laser device has been constructed as shown in FIGS. 4 and 5. Reference numeral 1 in FIG. 4 indicates a main body made of a single glass block having an extremely low coefficient of thermal expansion and having an approximately rectangular shape.

This main body 1 has a narrow rectangular ring-shaped optical path 2 in which a gas laser medium is sealed. At the corner of this optical path 2, a housing recess 3 for a gas reservoir is formed by opening on the outer surface of the corner of the main body 1, and this opening is hermetically closed by a reflecting mirror 4.

The main body 1 also has a first through hole 5I, which has one end communicating with the optical path 2 and the other end opening on the outer peripheral surface of the main body 1! ,,this first
A pair of second through holes 6 are bored symmetrically with respect to the through hole 5 . A cathode 7 is airtightly provided on the outer surface of the main body 1 facing the other end of the first through hole 5, and an anode 8 is airtightly provided on the outer surface of the main body 1 facing the other end of the second through hole 6. It is set in.

Furthermore, getters 9 are provided in two of the four accommodation recesses 3.
is located. As shown in FIG. 5, the getter 9 is formed into a ring shape with a smaller diameter than the accommodation recess 3 by a member having a U-shaped cross section, and the groove 9a is filled with barium (Ba).
A getter medium 11 made of an adsorbent such as the like is filled. The getter 9 is held by a holding member 12 with the open end of the groove 9a facing the bottom 3a of the accommodation recess 3, which is the side opposite to the reflecting mirror 4.

In such a configuration, when a discharge current is passed between the cathode 7 and the anode 8, the gas laser medium accommodated in the optical path 2 is optically excited, and two laser beams in opposite directions are generated, and the optical path 2
Because the laser beams run inside the main body 1, the optical path difference between these laser beams
rotation can be measured. Moreover, if the purity of the gas laser medium in the optical path 2 decreases due to repeated excitation, the output of one laser beam also decreases. In order to prevent such a situation, before introducing the laser medium, the getter 9 is heated from the outside by means such as high-frequency induction heating, and the getter medium 11 is evaporated and scattered to be deposited on the bottom of the accommodation recess 3. This allows impurity gases in the gas laser medium to be adsorbed, thereby increasing the purity of the laser medium.

However, if the getter 9 is heated rapidly, the evaporation rate of the evaporated getter medium 11 becomes faster.
1 may be reflected by the bottom 3a of the accommodation recess 3, pass through the inner diameter portion of the getter 9, and collide with and adhere to the reflection mirror 4 provided opposite to the accommodation recess 3. Getter medium 1
If 1 adheres to the reflecting mirror 4, it not only causes loss such as scattering of the laser beam, but in the worst case, the oscillation of the 1 noser light may stop.

(Problem to be Solved by the Invention) As described above, in the conventional ring-type laser device, when the getter medium is evaporated and scattered, the getter medium reflected at the accommodation recess may adhere to the reflection mirror. .

This invention was made based on the above-mentioned circumstances, and its purpose is to make it difficult for the getter medium that is evaporated and scattered by heating the getter and reflected at the accommodation recess to adhere to the reflecting mirror. An object of the present invention is to provide a ring-type laser device.

[Structure of the Invention] (Means and Effects for Solving the Problems) In order to solve the above problems, the present invention includes a main body in which a plurality of reflecting mirrors are provided at predetermined positions of an optical path to form a ring-shaped path; an accommodating recess formed in a portion of the main body facing the reflective surface of the reflective mirror so as to communicate with the optical path; and a getter provided in the accommodating recess at a position facing the reflective surface,
The bottom of the housing recess is formed as a regulating portion that reflects the getter medium evaporated and scattered from the getter to a portion other than the reflecting surface.

According to such a configuration, the regulating part provided at the bottom of the accommodation recess can prevent the evaporated and scattered getter medium from being reflected in the direction of exiting the accommodation recess, so that the getter medium is disposed facing the accommodation recess. This prevents the liquid from adhering to the reflective mirror.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. Note that the same parts as those in the conventional structure shown in FIGS. 4 and 5 are given the same symbols, and the description thereof will be omitted.

That is, in the ring laser device of the present invention,
A conical convex portion 21 as a regulating portion is provided at the bottom 3a of the accommodation recess 3 in which the getter 9 is held. As shown in FIG. 1, if the apex angle of the convex part 21 is A1, the maximum diameter of this convex part 21 is C1, the outer diameter of the getter 9 is D1, and the inner diameter is d, then D>
The maximum diameter C of the convex portion 21 is set so as to satisfy the relationship C>d. Further, when two extension lines g are extended from the top of the convex portion 21 so that the included angle X of these extension lines g is equal to the apex angle A, the interval between these extension lines g is Assuming that the position of the getter 9 that is equal to the outer diameter is B, the getter 9 is disposed at the position B or at a position between the position B and the bottom 3a of the accommodation recess 3.

In this way, the conical protrusion 21 is formed on the bottom 3a of the accommodation recess 3.
If the getter 9 is installed at the position B in the axial direction of the housing recess 3 or between the position B and the bottom 3a, the gelater medium 11 that evaporates and scatters by heating the getter 9 will be For example, even if ==I6 is reflected in the accommodation recess 3'' as shown by the arrows in Fig. 1,
This prevents the light from being reflected in the direction of exiting from the accommodation recess 3, that is, the direction of passing through the inner diameter portion of the getter 9.

That is, the arrow b1 in the figure indicates a case where the getter medium 11 evaporated and scattered from the getter 9 advances toward the radial center of the accommodation recess 3, in which case it collides with the surface of the convex portion 21. Since the surface of the convex portion 21 is inclined at an angle of A/2, the getter medium 11 is reflected from the surface at an angle equal to the incident angle, collides with the inner circumferential surface of the accommodation recess 3, and adheres thereto.

Further, arrow b2 indicates a case where the getter medium 11 directly collides with a portion of the bottom surface 3a of the accommodation recess 3 other than the convex portion 21.

Since the maximum diameter C of the convex portion 21 is set larger than the inner diameter d of the getter 9, the getter medium 11 collides with the bottom portion 3a of the accommodation recess 3 at an angle inclined outward in the radial direction. The reflected getter medium 11 does not pass through the inner diameter portion of the getter 9, but collides with and adheres to the inner peripheral surface of the accommodation recess 3 and the holding member 12.

Further, arrow C indicates a case where the getter medium 11 directly collides with the inner peripheral surface of the housing recess 3. In this case, most of the getter medium 11 reflected on the inner peripheral surface of the housing recess 3 collides with the surface of the convex portion 21. It sticks to the surface.

In this way, most of the getter medium 11 that evaporates and scatters from the getter 9 adheres to the inner peripheral surface of the accommodation recess 3 and the surface of the convex portion 21, passes through the inner diameter portion of the getter 9, and adheres to the reflection mirror 4. There is no such thing. Therefore, in order to adsorb impurity gas contained in the gas laser medium,
Even if the getter medium 11 is evaporated and scattered, it is possible to prevent the performance of the reflecting mirror 4 from being degraded.

This invention is not limited to the one embodiment described above, and can be modified in various ways without departing from the gist thereof. For example, although the regulating portion provided at the bottom of the accommodation recess is a conical convex portion, it may be a hemispherical or semi-elliptical convex portion, or even a concave portion may be used instead of the convex portion. In short, any shape is sufficient as long as the getter medium scattered from the getter is not reflected in the direction of passing through the inner diameter portion of the getter.

Furthermore, the optical path of a ring laser device to which the present invention can be applied is not limited to a rectangular shape, but may be triangular.

[Effects of the Invention] As described above, the present invention includes a regulating portion that prevents the getter medium evaporated and scattered from the getter from being reflected in the direction of adhering to the reflecting mirror, at the bottom of the accommodation recess in which the getter is held. . Therefore, it is possible to prevent the getter medium evaporated and scattered from the getter from adhering to the reflection mirror disposed opposite to the accommodation recess.

[Brief explanation of drawings]

FIG. 1 is an enlarged view of a housing recess formed in a main body showing an embodiment of the present invention, FIG. 2 is an explanatory view of the scattering state of the getter medium, and FIG. FIG. 4 is a plan view of the conventional overall configuration, and FIG. 5 is an explanatory diagram of the scattering state of the getter medium in the accommodation recess. DESCRIPTION OF SYMBOLS 1... Main body, 2... Optical path, 3... Accommodation recess, 4...
... Reflection mirror 9... Getter 11... Getter medium, 21... Conical convex part (regulating part).

Claims (1)

[Claims] a main body in which a plurality of reflective mirrors are provided at predetermined positions of the optical path to form a ring-shaped optical path; a housing recess formed in a portion of the body facing the reflective surface of the reflective mirror so as to communicate with the optical path; a getter provided in a position facing the reflective surface within the recess, the bottom of the housing recess being formed as a regulating portion that reflects the getter medium evaporated and scattered from the getter to a portion other than the reflective surface; A ring-shaped laser device featuring: