JP2009212416A - Method of manufacturing gas cell, and gas cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a gas cell having a good optical window with excellent mass productivity, in which a dicing plane is made into a laser passing window, and a gas introducing path is provided as a metal holder. <P>SOLUTION: The method of manufacturing the gas cell includes: a step A of completing a processed glass substrate 20 projected a gas introducing cylinder 3 on the glass substrate 1; a step B of completing a processed glass substrate 21 having a rectangular second through-hole 5; a step C of completing a processed glass substrate 22 having a rectangular recess 7; a step D of forming a gas holding portion 9 for holding an alkali metal vapor in the glass substrate laminated body 23, filling rubidium (alkali metal) gas 8 from the opening 3a of the gas introducing cylinder 3 under an inert gas environment, sealing the opening 3a by welding, and dicing along a cutting line 25. As a result, a gas cell 26 having planes A to D are formed parallel to respective planes of the gas holding portion 9. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a gas cell, and more particularly to a method for manufacturing a gas cell for enhancing mass productivity of a small and thin gas cell.

In recent years, digital networks such as communication networks and broadcasting networks have been developed, and accordingly, a highly accurate and highly stable oscillator is required as a clock source used for generating clock signals for transmission devices and reference frequencies for broadcasting stations. It has become indispensable. As such an oscillator, an atomic oscillator having high oscillation frequency accuracy and stability is often used. In an atomic oscillator, a site where alkali metal atoms such as rubidium and cesium interact with light is necessary, and a gas cell in which these atoms are hermetically sealed is generally used as a component for that purpose. In recent years, the demand for miniaturization of atomic oscillators has increased, and along with this miniaturization, gas cells have been forced to be smaller and thinner. The gas cell is manufactured by the manufacturing process shown in FIG. 5 in order to reduce the thickness (see Patent Document 1). That is, the silicon wafer 50 is polished on both sides in the step (a), the opening 51 is formed by etching in the silicon wafer 50 in the step (b), and 1000 V is applied from the power source 53 in the step (c) at 300 ° C. The lower glass substrate 52 is anodically bonded. Further, in step (d), cesium (alkali metal) and a buffer gas 54 are introduced into the opening 51 under an inert atmosphere, and in step (e), the upper glass substrate 55 is anodically bonded. In step (f), a cesium-filled gas cell is formed. 56 is completed. The gas cell 56 obtained by this process is arranged in the direction of FIG.
US6808064B2

However, the gas cell according to the conventional manufacturing process has a light receiving unit 60, an ITO 61, a gas cell 56, an ITO 62, a lens unit 63, and a light emitting unit 64 stacked vertically as shown in FIG. 7, and the laser beam is emitted upward from the lowest stage. Is done. Then, each chip 60a is diced to produce one optical system. Therefore, there is no room for forming the metal reservoir in the gas cell 56. As a result, there is a problem that the metal adheres to the window portion through which the laser beam is transmitted and the transmittance is lowered or the laser beam is blocked. .
The present invention has been made in view of such problems, and includes a first glass substrate in which a plurality of through holes are opened and a gas introduction tube portion is formed at a position where the through holes can communicate with each other. A second glass substrate having a through-hole having a shape and a third glass substrate are provided, and these are laminated and joined, and then dicing is performed, so that the dicing surface serves as a laser light transmission window, and the gas introduction tube portion An object of the present invention is to provide a method of manufacturing a gas cell having an optical window that is excellent in mass productivity and has a good optical window.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A step of preparing a first transparent substrate including a plurality of first through holes and a gas introduction tube portion projecting from the surface side opening of each first through hole; Providing a second transparent substrate having a rectangular second through-hole that is larger in diameter than the first through-hole at a position where it can communicate with each first through-hole of the transparent substrate; A step of preparing a third transparent substrate, and the first transparent substrate and the second transparent substrate are sequentially stacked and bonded to the back side of the first transparent substrate. A transparent substrate stacking step for forming a transparent substrate laminate having a plurality of cavities made of through-holes, and filling each space of the transparent substrate laminate with alkali metal vapor from each of the gas introduction cylinders for sealing. Cutting the sealing substrate and cutting the transparent substrate laminate within the thickness of the transparent substrate material located between the voids. Characterized by comprising a step of forming a plurality of the gas cell, the by.

  In the gas cell manufacturing method of the present invention, three transparent substrates are prepared, a plurality of first through holes are formed in the first transparent substrate, and the first through holes are protruded from the surface side opening. The gas introduction tube portion thus formed is formed. Further, the second transparent substrate is formed with a second through-hole having a diameter larger than that of the first through-hole and a rectangular shape at a position where it can communicate with each first through-hole. In addition, a third transparent substrate that seals the second through hole formed in the second transparent substrate is prepared. Then, these transparent substrates are sequentially laminated and bonded. After that, alkali metal vapor is filled from each gas introduction path and sealed. And the joined transparent substrate laminated body is cut | disconnected within the thickness of the transparent substrate material located between each cavity. As a result, a plurality of gas cells can be manufactured in a single process, and the mass production effect can be enhanced.

  Application Example 2 A concave portion communicating with each of the second through holes is formed on the inner side surface of the third transparent substrate.

  In Application Example 1, the third transparent substrate is necessary for sealing the opening formed in the second transparent substrate. However, since this opening is a room filled with gas in the gas cell, Volume is needed. Therefore, in the present invention, the inner surface of the third transparent substrate is provided with a recess that communicates with each second through hole. Thereby, the volume of the room filled with the gas in the gas cell can be increased.

  Application Example 3 The second application example is characterized in that the second transparent substrate and the third transparent substrate are integrally formed in advance.

  The present invention integrates the second and third transparent substrates of Application Example 1 to reduce the number of parts. That is, the thickness of the integrated transparent substrate is increased to form a rectangular recess without being completely penetrated. Thereby, since a manufacturing process can be reduced, while being able to reduce manufacturing cost, the number of parts can be reduced.

  Application Example 4 The first to third transparent substrates are made of glass.

  The transparent substrate is preferably made of a material having a high transmittance in order to transmit the laser light without being attenuated. Moreover, since it is necessary to form an opening etc. in a transparent substrate or to laminate | stack and join, the material which is excellent in workability and has high flatness is preferable. In that respect, glass is most suitable. Thereby, a gas cell with high light transmittance, excellent workability, and high flatness can be manufactured.

  Application Example 5 A feature is that a cut surface of the transparent substrate laminate is a light transmission portion.

  Since the transparent substrate is made of glass, the cut surface has high light transmittance and high flatness. Thereby, it can be set as the surface which installs the heater for heating other 2 surfaces by making 2 surfaces which oppose among 4 cut surfaces into a light transmissive window.

  Application Example 6 A gas cell is manufactured by the method for manufacturing a gas cell according to any one of claims 1 to 5.

  According to the manufacturing method of the present invention, a large number of gas cells can be manufactured in a single process, so that gas cells with uniform quality can be mass-produced.

  [Application Example 7] The application example is characterized in that the gas introduction path is a metal reservoir for storing excess metal in the gas cell.

  The gas cell needs a metal reservoir for storing metal that could not be diffused. In this invention, it functions as a metal reservoir part which stores an excess metal by keeping a gas introduction path lower than other temperature. Thereby, the metal adhering to the transmission window can be collected in the gas introduction path, and the light transmittance of the transmission window can be increased.

Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the components, types, combinations, shapes, relative arrangements, and the like described in this embodiment are merely illustrative examples and not intended to limit the scope of the present invention only unless otherwise specified. .
Fig.1 (a) is a schematic diagram explaining an example of the gas cell manufacturing method of this invention. In this gas cell manufacturing method, for example, three glass substrates 1, 4, 6 are joined and diced for each chip. That is, in the gas cell manufacturing method of the present invention, for example, three glass substrates are prepared, and the glass substrate 1 (first transparent substrate) has a plurality of first through holes 2 and first through holes. The gas introduction cylinder part 3 projected from the front surface side opening 2 is formed. Further, the glass substrate 4 (second transparent substrate) has a rectangular shape that is larger in diameter than the first through-hole 2 at a position where it can communicate with each first through-hole 2 formed in the glass substrate 1. A second through hole 5 is formed. Also, a glass substrate 6 (third transparent substrate) that seals the second through-hole 5 formed in the glass substrate 4 is prepared. And these glass substrates 1, 4, and 6 are laminated | stacked and joined sequentially, and the glass substrate laminated body (transparent substrate laminated body) 23 is formed. Thereafter, rubidium gas, which is an alkali metal, is filled from each gas introduction cylinder portion 3 into each space 9 of the glass substrate laminate 23 and sealed. And the glass substrate laminated body 23 is cut | disconnected within the thickness of the glass substrate material located between each cavity 9. FIG. As a result, a plurality of gas cells 26 can be manufactured in a single process, and the mass production effect can be enhanced.
FIG. 1B is a perspective view of a gas cell manufactured by cutting the glass substrate laminate 23. Since the glass substrate laminate 23 is cut in parallel to each surface of the void 9, the laser light emitted from the light source 30 enters from the B surface of the gas cell 26 and exits from the D surface of the opposite surface. Then, the light can enter the detector 31. In this figure, the B surface and the D surface are used, but the A surface and the C surface may be used.

  FIG. 2 is a view showing a cut surface of each glass substrate. The same components will be described with the same reference numerals as in FIG. 2 (a) is a cross-sectional view of the glass substrate 1, FIG. 2 (b) is a cross-sectional view of the glass substrate 4, FIG. 2 (c) is a cross-sectional view of the glass substrate 6, and FIG. A sectional view of the glass substrate laminate 23 is shown. In other words, the glass substrate 1 is joined to the first through-hole 2 and the gas introduction cylinder portion 3 protruding from the surface-side opening of each first through-hole 2 at the A portion (FIG. 2A). ). Further, the glass substrate 4 has a second through-hole 5 having a diameter larger than that of the first through-hole 2 and a rectangular shape at a position where it can communicate with each first through-hole 2 formed in the glass substrate 1. It is formed (FIG. 2B). Further, the glass substrate 6 is formed with recesses 7 respectively communicating with the respective second through holes 5 (FIG. 2C). Then, when the glass substrate laminate 23 is formed by sequentially laminating and joining the glass substrates 1, 4, and 6 as shown in FIG. (Referred to as a reservoir) 9 is formed in the glass substrate laminate 23.

FIG. 3 is a schematic diagram for explaining the steps of the gas cell manufacturing method according to the first embodiment of the present invention. In this figure, in order to simplify the description, it is assumed that one gas cell is manufactured on a glass substrate. Actually, as shown in FIG. 1, a plurality of gas cells are simultaneously manufactured on the glass substrate by the same process.
In the gas cell manufacturing method of the present invention, as step A, the first through-hole 2 is opened in the circular glass substrate 1 (FIG. Aa) (FIG. Ab), and the surface of the first through-hole 2 is formed. The gas introduction cylinder part 3 protruding from the side opening is joined (the joining method is that the gas introduction cylinder part 3 is made of homogeneous glass, and the joining surface between the glass substrate 1 and the gas introduction cylinder part 3 is polished and adhered. By doing so, both can be easily joined.) (FIG. Ac). Thereby, the processed glass substrate 20 in which the gas introduction cylinder portion 3 protrudes from the glass substrate 1 is completed.
Next, as the process B, another circular glass substrate 4 (FIG. Ba) is larger in diameter than the first through-hole 2 and has a rectangular shape at a position where it can communicate with the first through-hole 2. The second through hole 5 is formed (FIG. B-b). Thereby, the processed glass substrate 21 having the rectangular second through-hole 5 is completed.

Next, as step C, recesses 7 respectively communicating with the second through holes 5 are formed on the inner surface of another circular glass substrate 6 (FIG. Ca) (FIG. Cb). Thereby, the processed glass substrate 22 which has the rectangular recessed part 7 is completed.
Next, as the process D, the processed glass substrates 20 to 22 are sequentially laminated (Da), and they are joined to form the glass substrate laminate 23 (Db). The joining method is the same as in step A. Thereby, the gas storage part 9 which stores rubidium gas in the glass substrate laminated body 23 is formed. Next, the rubidium gas 8 is filled from the opening 3a of the gas introduction cylinder 3 under an inert atmosphere (Dc). Then, the opening 3a is welded and sealed with a gas burner or the like (not shown) (reference numeral 24) and diced along the cutting line 25 (Dd). The cutting line 25 cuts the glass substrate laminate 23 within the thickness of the glass substrate material located between the gas storage portions 9. As a result, the gas cell 26 having the surfaces A to D parallel to the respective surfaces of the gas storage unit 9 is completed (De).

That is, the glass substrate 6 is necessary for sealing the second through-hole 5 formed in the glass substrate 4, but the second through-hole 5 becomes a room filled with rubidium gas. Volume is needed. Therefore, in the present embodiment, the concave portion 7 that communicates with the second through-hole 5 is provided on the inner surface of the glass substrate 6. Thereby, the volume of the room filled with rubidium gas can be increased. As a result, a plurality of gas cells can be manufactured in a single process, and the mass production effect can be enhanced.
The transparent substrate is preferably made of a material having a high transmittance in order to transmit the laser light without being attenuated. Moreover, since it is necessary to form a through-hole etc. in a transparent substrate, or to laminate | stack and join, the material which is excellent in workability and has high flatness is preferable. In that respect, glass is most suitable. Thereby, a gas cell with high light transmittance, excellent workability, and high flatness can be manufactured.

Moreover, as a gas cell manufacturing method according to the second embodiment of the present invention, the glass substrate 6 is not formed with the recesses 7 in step C of FIG. 3, and the processed glass substrate 20, the processed glass substrate 21, and the glass substrate 6 are used to form glass. You may complete the board | substrate laminated body 23. FIG.
Further, as a gas cell manufacturing method according to the third embodiment of the present invention, the processed glass substrate 21 and the processed glass substrate 22 may be integrally configured in advance as shown in FIG. That is, the concave portion 11 having a volume equal to the volume formed by the through hole 5 and the concave portion 7 is formed in the thick glass substrate 10. In the present invention, the processed glass substrates 21 and 22 are integrated to reduce the number of parts. That is, the thickness of the integrated glass substrate 10 is increased, and the rectangular recess 11 is formed without being completely penetrated. Thereby, since a manufacturing process can be reduced, while being able to reduce manufacturing cost, the number of parts can be reduced.

  Since a large number of gas cells can be manufactured in a single process by the above manufacturing method, gas cells with uniform quality can be mass-produced. Moreover, let the gas introduction cylinder part 3 be a metal reservoir part which stores the surplus metal in a gas cell. That is, the gas reservoir needs a metal reservoir for storing the metal that could not be diffused. In this invention, it functions as a metal reservoir part which stores excess metal by keeping the gas introduction cylinder part 3 lower than other temperature. Thereby, the metal adhering to the transmission window can be collected in the gas introduction cylinder part 3 to increase the light transmittance of the transmission window.

(A) is a schematic diagram explaining an example of the gas cell manufacturing method of this invention, (b) is a perspective view of the gas cell manufactured by cut | disconnecting the glass substrate laminated body 23. FIG. (A) is sectional drawing of the glass substrate 1, (b) is sectional drawing of the glass substrate 4, (c) is sectional drawing of the glass substrate 6, (d) is joining each glass substrate, and the glass substrate laminated body 23 and FIG. It is a schematic diagram explaining the process of the gas cell manufacturing method which concerns on the 1st Embodiment of this invention. It is a perspective view of the gas cell manufacturing method which concerns on the 3rd Embodiment of this invention. (A)-(f) is a figure explaining the manufacturing process of the conventional gas cell. It is sectional drawing of the conventional gas cell. It is a schematic diagram explaining the optical system by the conventional manufacturing method.

Explanation of symbols

  1, 4, 6, 10 Glass substrate, 2 1st through-hole, 3 gas introduction cylinder part, 5 2nd through-hole, 7, 11 recessed part, 8 rubidium gas, 9 gas storage part, 20, 21, 22 Glass substrate

Claims (7)

Preparing a first transparent substrate having a plurality of first through-holes and a gas introduction tube portion projecting from the surface-side opening of each first through-hole;
A second transparent substrate having a second through-hole that is larger in diameter than the first through-hole and has a rectangular second through-hole is provided at a position where it can communicate with each first through-hole of the first transparent substrate. And a process of
Preparing a third transparent substrate;
The second transparent substrate and the third transparent substrate are sequentially stacked and bonded to the back surface side of the first transparent substrate, thereby providing a plurality of voids including the first and second through holes. A transparent substrate lamination step for forming a transparent substrate laminate,
A sealing step of filling and sealing an alkali metal vapor in each space of the transparent substrate laminate from each of the gas introduction cylinders;
Forming the plurality of gas cells by cutting the transparent substrate laminate within the thickness of the transparent substrate material positioned between the voids.   The method for manufacturing a gas cell according to claim 1, wherein a concave portion communicating with each of the second through holes is formed on an inner surface of the third transparent substrate.   The method for manufacturing a gas cell according to claim 1 or 2, wherein the second transparent substrate and the third transparent substrate are integrally formed in advance.   The method of manufacturing a gas cell according to any one of claims 1 to 3, wherein the first to third transparent substrates are made of glass.   The method for producing a gas cell according to any one of claims 1 to 4, wherein a cut surface of the transparent substrate laminate is used as a light transmission part.   A gas cell manufactured by the method for manufacturing a gas cell according to any one of claims 1 to 5.   The gas cell according to claim 6, wherein the gas introduction path is a metal reservoir that stores excess metal in the gas cell.

Images