JP2014039180A - Gas cell unit, atomic oscillator and electronic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gas cell unit and an atomic oscillator that simply and reliably hold a coil in close contact with an inner circumferential surface of a package housing a gas cell without employing in the coil a member for supporting the coil, and provide an electronic apparatus that reliably has such an atomic oscillator.SOLUTION: The gas cell unit (second unit 3) includes a gas cell 31 filled with gaseous metal atoms, a coil 35 disposed around the gas cell 31, and the package (second package 36) for housing the gas cell 31 and the coil 35. The coil 35 comprises a wiring pattern of a flexible wiring board, and the flexible wiring board is cylindrically wrapped in the package, so that the resilience of the flexible wiring board presses on an inner wall surface of the package.

Description

  The present invention relates to a gas cell unit, an atomic oscillator, and an electronic device.

2. Description of the Related Art An atomic oscillator that oscillates based on energy transition of an alkali metal atom such as rubidium or cesium is known (see, for example, Patent Document 1).
Such an atomic oscillator generally includes a gas cell in which an alkali metal is enclosed with a buffer gas, a light emitting element that emits excitation light that excites the alkali metal in the gas cell, and a light receiving element that detects excitation light that has passed through the gas cell. Prepare.

  Conventionally, in such an atomic oscillator, for example, as described in Patent Document 1, a coil is arranged around a gas cell, and a stationary magnetic field is generated by the coil, thereby degenerating alkali metal atoms in the gas cell. The splitting of multiple energy levels is performed (Zeeman splitting). Here, control is performed so that only the energy level having a magnetic quantum number of 0 that is least affected by the magnetic field strength change is selected among the plurality of split energy levels, and the influence of the magnetic field strength change is reduced as much as possible. ing. On the other hand, the alkali metal atoms vaporized in the gas cell are distributed with a spatial spread. It is desirable to apply a magnetic field having a uniform magnetic field intensity distribution to the alkali metal atoms having such a spatial spread. The reason is that if there is a region where the magnetic field strength is not uniform, alkali metal atoms present in the region are affected by the change in the magnetic field strength and affect the frequency accuracy of the output signal of the atomic oscillator. Thus, the non-uniformity of the magnetic field strength distribution affects the frequency accuracy of the atomic oscillator.

Therefore, in order to make the distribution of the magnetic field strength uniform, the coil that generates a stationary magnetic field is in close contact with the inner wall surface of the high-permeability package that houses the gas cell as much as possible in order to provide stable oscillation characteristics. It is necessary to arrange. The reason is that if the gap between the coil and the inner wall surface of the package becomes large, the strength of the magnetic field in the vicinity of the end of the coil will not be uniform, and a uniform magnetic field cannot be applied to the entire alkali metal atoms.
However, the conventional atomic oscillator has a problem that the coil cannot be sufficiently adhered to the inner peripheral surface of the package.

More specifically, for example, conventionally, the coil is housed in the package by the following two methods.
In the first method, a hollow core material having an outer diameter smaller than the inner diameter of the package by an amount corresponding to the thickness of the coil is prepared, the coil is installed on the outer periphery of the core material, and then the core material and the coil are inserted into the package. In this method, the coil cannot be brought into close contact with the inner peripheral surface of the package due to variations in the dimensional accuracy of the core material. Moreover, since a core material is required, the design freedom of the member arrange | positioned inside a coil will fall.
In the second method, a coil having an outer diameter matching the inner diameter of the package is formed by bonding with an adhesive, and the coil is inserted into the package. In such a method, the coil cannot be brought into close contact with the inner peripheral surface of the package due to variations in the dimensional accuracy of the coil. Further, it takes time and effort to harden the coil with an adhesive.

US Pat. No. 6,320,472

  SUMMARY OF THE INVENTION An object of the present invention is to provide a gas cell unit and an atomic oscillator capable of securely bringing a coil into close contact with the inner peripheral surface of a package containing a gas cell, and to provide an electronic device having such an atomic oscillator and excellent in reliability. Is to provide.

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]
The gas cell unit of the present invention includes a gas cell in which gaseous metal atoms are enclosed,
A coil that is provided around the gas cell and is configured by a wiring pattern of a flexible wiring board;
A package for housing the gas cell and the coil,
The flexible wiring board is rounded into a cylindrical shape within the package, and is pressed against the inner wall surface of the package by the elastic force of the flexible board.

  According to the gas cell unit configured as described above, when the coil is installed in the package at the time of manufacturing the gas cell unit, the coil is placed on the inner wall surface of the package by the restoring force or the elastic force of the flexible wiring board rolled into a cylindrical shape. It can be adhered. Therefore, the coil can be brought into close contact with the inner wall surface of the package relatively easily and reliably. In addition, since it is not necessary to provide a member for supporting the coil inside the coil, the degree of freedom in designing the member disposed inside the coil can be increased.

[Application Example 2]
In the gas cell unit of the present invention, the inner wall surface of the package preferably has a cylindrical shape.
Thereby, the coil can be brought into close contact with the inner wall surface of the package in a wide range easily and reliably.

[Application Example 3]
In the gas cell unit of the present invention, the package is preferably made of a magnetic material.
Thereby, the magnetic field generated by the coil can be efficiently guided to the gas cell.
[Application Example 4]
In the gas cell unit of the present invention, the magnetic material is preferably a soft magnetic material.
Thereby, the magnetic field generated by the coil can be more efficiently guided to the gas cell.

[Application Example 5]
In the gas cell unit of the present invention, the gas cell unit further comprises a substrate housed in the package, on which the gas cell is installed,
The substrate is a rigid substrate, and is preferably formed integrally with the flexible wiring substrate.
Thereby, the flexible wiring board for forming a coil and the board | substrate for installing a gas cell can be formed simultaneously. Further, when assembling the gas cell unit, it is possible to save the trouble of connecting these substrates. In addition, the connection reliability can be improved.

[Application Example 6]
The atomic oscillator of the present invention includes the gas cell unit of the present invention,
A light emitting element that emits excitation light that excites the gaseous metal atoms in the gas cell;
And a light receiving element that is housed in the package and detects the excitation light transmitted through the gas cell.
Thereby, an atomic oscillator having excellent oscillation characteristics can be provided.

[Application Example 7]
In the atomic oscillator of the present invention, the light emitting element is disposed outside the package,
It is preferable that the package has a window portion that transmits the excitation light from the light emitting element.
Thereby, thermal interference between the gas cell and the light emitting element can be prevented. As a result, the oscillation characteristics of the atomic oscillator can be improved.
[Application Example 8]
An electronic apparatus according to the present invention includes the atomic oscillator according to the present invention.
Thereby, an electronic device having excellent reliability can be provided.

1 is a perspective view showing an atomic oscillator according to a first embodiment of the present invention. It is a schematic diagram which shows schematic structure of the atomic oscillator shown in FIG. It is a figure for demonstrating the energy state of the alkali metal in the gas cell with which the atomic oscillator shown in FIG. 1 was equipped. 2 is a graph showing a relationship between a frequency difference between two lights from a light emitting element and a detection intensity at the light receiving element with respect to the light emitting element and the light receiving element provided in the atomic oscillator shown in FIG. 1. It is a longitudinal cross-sectional view of the atomic oscillator shown in FIG. It is a longitudinal cross-sectional view of the gas cell unit of the atomic oscillator shown in FIG. It is a cross-sectional view of the gas cell unit of the atomic oscillator shown in FIG. It is a figure which shows the state which expand | deployed the coil (flexible wiring board) shown in FIG. 6 and FIG. It is a figure for demonstrating the coil (flexible wiring board) shown in FIG. It is a cross-sectional view showing a gas cell unit according to a second embodiment of the present invention. It is a longitudinal cross-sectional view which shows the gas cell unit which concerns on 3rd Embodiment of this invention. It is a figure which shows schematic structure at the time of using the electronic device of this invention for the positioning system using a GPS satellite. It is a schematic block diagram which shows an example of the clock transmission system using the atomic oscillator of this invention.

Hereinafter, an atomic oscillator and an electronic apparatus of the present invention will be described in detail based on embodiments shown in the accompanying drawings.
<First Embodiment>
1 is a perspective view showing an atomic oscillator according to a first embodiment of the present invention, FIG. 2 is a schematic diagram showing a schematic configuration of the atomic oscillator shown in FIG. 1, and FIG. 3 is provided in the atomic oscillator shown in FIG. FIG. 4 is a diagram for explaining the energy state of the alkali metal in the gas cell, FIG. 4 shows the frequency difference between the two lights from the light emitting element, and the light emitting element and the light receiving element provided in the atomic oscillator shown in FIG. FIG. 5 is a longitudinal sectional view of the atomic oscillator shown in FIG. 1, FIG. 6 is a longitudinal sectional view of the gas cell unit of the atomic oscillator shown in FIG. 1, and FIG. 1 is a cross-sectional view of the gas cell unit of the atomic oscillator shown in FIG. 1, FIG. 8 is a diagram showing a state where the coil (flexible wiring board) shown in FIGS. 6 and 7 is developed, and FIG. In the figure for explaining the wiring board) That.

  1, 5, and 6, for convenience of explanation, the X axis, the Y axis, and the Z axis are illustrated as three axes orthogonal to each other, and the tip side of each illustrated arrow is “+ side”. The base end side is defined as “− side”. In the following, for convenience of explanation, a direction parallel to the X axis is referred to as “X axis direction”, a direction parallel to the Y axis is referred to as “Y axis direction”, and a direction parallel to the Z axis is referred to as “Z axis direction”. Further, the + Z direction side (upper side in FIG. 5) is referred to as “upper”, and the −Z direction side (lower side in FIG. 5) is referred to as “lower”.

An atomic oscillator 1 shown in FIG. 1 is an atomic oscillator using a quantum interference effect.
As shown in FIG. 1, the atomic oscillator 1 includes a first unit 2, a second unit 3 (gas cell unit), optical components 41, 42, and 43, and a holding member 5 that holds them.
Here, as shown in FIGS. 1 and 2, the first unit 2 includes a light emitting element 21 and a first package 22 that houses the light emitting element 21.

The second unit 3 includes a gas cell 31, a light receiving element 32, a heater 33, a temperature sensor 34, a coil 35, and a second package 36 that houses these.
The first unit 2 and the second unit 3 are driven and controlled by the control unit 6.
First, the principle of the atomic oscillator 1 will be briefly described.

In the atomic oscillator 1, gaseous metal such as rubidium, cesium, and sodium (metal atom) is enclosed in a gas cell 31.
As shown in FIG. 3, the alkali metal has a three-level energy level, and is in three states, two ground states (ground states 1 and 2) having different energy levels, and an excited state. Can take. Here, the ground state 1 is a lower energy state than the ground state 2.

When two types of resonant lights 1 and 2 having different frequencies are irradiated onto such a gaseous alkali metal, the above-described gaseous alkali metal is irradiated with the frequency ω 1 of the resonant light 1 and the frequency ω 2 of the resonant light 2. In accordance with the difference (ω1-ω2), the light absorptivity (light transmittance) of the resonance lights 1 and 2 in the alkali metal changes.
When the difference (ω1−ω2) between the frequency ω1 of the resonant light 1 and the frequency ω2 of the resonant light 2 matches the frequency corresponding to the energy difference between the ground state 1 and the ground state 2, the ground states 1 and 2 Each excitation to the excited state stops. At this time, both the resonant lights 1 and 2 are transmitted without being absorbed by the alkali metal. Such a phenomenon is called a CPT phenomenon or an electromagnetically induced transparency (EIT) phenomenon.
The light emitting element 21 emits two types of light (resonant light 1 and resonant light 2) having different frequencies as described above toward the gas cell 31.

  For example, when the light emitting element 21 fixes the frequency ω1 of the resonant light 1 and changes the frequency ω2 of the resonant light 2, the difference between the frequency ω1 of the resonant light 1 and the frequency ω2 of the resonant light 2 (ω1-ω2). 4 coincides with the frequency ω 0 corresponding to the energy difference between the ground state 1 and the ground state 2, the detection intensity of the light receiving element 32 increases sharply as shown in FIG. Such a steep signal is detected as an EIT signal. This EIT signal has an eigenvalue determined by the type of alkali metal. Therefore, an oscillator can be configured by using such an EIT signal.

Hereinafter, each part of the atomic oscillator 1 will be described in detail sequentially.
(First unit)
As described above, the first unit 2 includes the light emitting element 21 and the first package 22 that houses the light emitting element 21.
[Light emitting element]
The light emitting element 21 has a function of emitting excitation light that excites alkali metal atoms in the gas cell 31.

More specifically, the light emitting element 21 emits two types of light (resonant light 1 and resonant light 2) having different frequencies as described above.
The frequency ω1 of the resonant light 1 can excite the alkali metal in the gas cell 31 from the ground state 1 to the excited state.
Further, the frequency ω2 of the resonance light 2 can excite the alkali metal in the gas cell 31 from the ground state 2 to the excited state.

The light emitting element 21 is not particularly limited as long as it can emit the excitation light as described above. For example, a semiconductor laser such as a vertical cavity surface emitting laser (VCSEL) can be used.
Further, such a light emitting element 21 is temperature-adjusted to a temperature different from a gas cell 31 described later, for example, about 30 ° C., by a temperature adjusting element (a heating resistor, a Peltier element, etc.) not shown.

[First package]
The first package 22 houses the light emitting element 21 described above.
As shown in FIG. 5, the first package 22 includes a base 221 (first base) and a lid 222 (first lid).
The base 221 supports the light emitting element 21 directly or indirectly. In the present embodiment, the base body 221 has a plate shape and a circular shape in plan view.

The light emitting element 21 (mounting component) is installed (mounted) on one surface (mounting surface) of the base 221. Further, as shown in FIG. 5, a plurality of leads 223 protrude from the other surface of the base 221. The plurality of leads 223 are electrically connected to the light emitting element 21 via wiring (not shown).
A lid body 222 that covers the light emitting element 21 on the base body 221 is bonded to the base body 221.

The lid 222 has a bottomed cylindrical shape with one end opened. In the present embodiment, the cylindrical portion of the lid 222 has a cylindrical shape.
The opening at one end of the lid 222 is closed by the base 221 described above.
A window 23 is provided at the other end of the lid 222, that is, at the bottom opposite to the opening of the lid 222.

The window portion 23 is provided on the optical axis a between the gas cell 31 and the light emitting element 21.
And the window part 23 has transparency with respect to the excitation light mentioned above.
In this embodiment, the window part 23 is comprised with the lens. Thereby, the excitation light LL can be irradiated to the gas cell 31 without waste.
Moreover, the window part 23 has a function which makes the excitation light LL parallel light. Thereby, it is possible to easily and reliably prevent the excitation light LL from being reflected by the inner wall of the gas cell 31. Therefore, resonance of excitation light in the gas cell 31 is preferably generated, and as a result, the oscillation characteristics of the atomic oscillator 1 can be enhanced.

The window 23 is not limited to a lens as long as it has transparency to excitation light, and may be, for example, an optical component other than a lens, or a simple light-transmissive plate member. Also good. Further, the lens having the above-described function may be provided between the first package 22 and the second package 36 as in the optical components 41, 42, and 43 described later.
The constituent material of the lid body 222 other than the window portion 23 is not particularly limited, and for example, ceramic, metal, resin, or the like can be used.

  Here, when a portion other than the window portion 23 of the lid 222 is made of a material that is transparent to excitation light, the portion other than the window portion 23 of the lid 222 and the window portion 23 are formed integrally. can do. Further, when the portion other than the window portion 23 of the lid 222 is made of a material that is not transmissive to the excitation light, the portion other than the window portion 23 of the lid 222 and the window portion 23 are separated. These may be formed and bonded by a known bonding method.

Moreover, it is preferable that the base body 221 and the lid 222 are airtightly joined. That is, it is preferable that the inside of the first package 22 is an airtight space. Thereby, the inside of the 1st package 22 can be made into a pressure reduction state or an inert gas enclosure state, As a result, the characteristic of the atomic oscillator 1 can be improved.
The method for joining the base 221 and the lid 222 is not particularly limited, and for example, brazing, seam welding, energy beam welding (laser welding, electron beam welding, etc.), and the like can be used.
A joining member for joining these may be interposed between the base 221 and the lid 222.

In addition, the first package 22 may contain components other than the light emitting element 21 described above.
For example, the first package 22 may contain a temperature adjustment element, a temperature sensor, or the like that adjusts the temperature of the light emitting element 21. Examples of such temperature adjusting elements include heating resistors (heaters), Peltier elements, and the like.
According to the first package 22 configured to include the base body 221 and the lid body 222 as described above, the first light emitting element 21 is arranged while allowing the excitation light to be emitted from the light emitting element 21 to the outside of the first package 22. It can be stored in the package 22.

Further, since the light emitting element 21 is disposed outside the second package 36 described later, thermal interference between the gas cell 31 and the light emitting element 21 can be prevented. As a result, the oscillation characteristics of the atomic oscillator 1 can be improved.
Further, the first package 22 is held by a holding member 5 to be described later so that the base 221 is disposed on the side opposite to the second package 36.

(Second unit)
As described above, the second unit 3 includes the gas cell 31, the light receiving element 32, the heater 33, the temperature sensor 34, the coil 35, and the second package 36 that houses them. In FIG. 6, the temperature sensor 34 is not shown.

[Gas cell]
The gas cell 31 is filled with gaseous alkali metals such as rubidium, cesium, and sodium.
As shown in FIG. 6, the gas cell 31 includes a main body portion 311 having a columnar through hole and a pair of windows 312 and 313 that block both openings of the through hole. Thereby, the internal space S in which the alkali metal as described above is enclosed is formed.

Here, each of the window portions 312 and 313 of the gas cell 31 has transparency to the excitation light from the light emitting element 21 described above. One window 313 transmits excitation light incident into the gas cell 31, and the other window 312 transmits excitation light emitted from the gas cell 31.
Therefore, the material constituting the window portions 312 and 313 of the gas cell 31 is not particularly limited as long as it has transparency to the excitation light as described above, and examples thereof include glass materials and crystal.

Moreover, the material which comprises the main-body part 311 of the gas cell 31 is not specifically limited, A metal material, a resin material, etc. may be sufficient and a glass material, a crystal | crystallization, etc. may be sufficient like the window parts 312,313.
The window portions 312 and 313 are airtightly joined to the main body portion 311. Thereby, the internal space S of the gas cell 31 can be made into an airtight space.

The joining method of the main body 311 and the windows 312 and 313 of the gas cell 31 is determined according to these constituent materials, and is not particularly limited. For example, a joining method using an adhesive, a direct joining method, an anode A bonding method or the like can be used.
Further, the temperature of the gas cell 31 is adjusted by the heater 33 to a temperature different from that of the light emitting element 21 described above, for example, about 70 ° C.

[Light receiving element]
The light receiving element 32 has a function of detecting the intensity of the excitation light LL (resonant light 1 and 2) transmitted through the gas cell 31.
The light receiving element 32 is not particularly limited as long as it can detect the excitation light as described above. For example, a photodetector (light receiving element) such as a solar cell or a photodiode can be used.

[heater]
The heater 33 has a function of heating the above-described gas cell 31 (more specifically, an alkali metal in the gas cell 31). Thereby, the alkali metal in the gas cell 31 can be maintained in a gaseous state.
The heater 33 generates heat when energized, and includes heating resistors 331 and 332 provided on the outer surface of the gas cell 31, as shown in FIG. Such heat generating resistors 331 and 332 are formed using, for example, a chemical vapor deposition method (CVD) such as plasma CVD or thermal CVD, a dry plating method such as vacuum vapor deposition, a sol-gel method, or the like.

Here, the heating resistor 331 is provided on the window 312 of the gas cell 31, and the heating resistor 332 is provided on the window 313 of the gas cell 31. That is, the heating resistors 331 and 332 are provided at the excitation light incident portion or the emission portion of the gas cell 31.
The heating resistors 331 and 332 are made of a material having transparency to excitation light, specifically, for example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), In ₃ O ₃ , SnO ₂ , Sb-containing SnO. _2. It is comprised with transparent electrode materials, such as oxides, such as Al containing ZnO.

The heater 33 is not particularly limited as long as it can heat the gas cell 31, and may be non-contact with the gas cell 31. Further, the gas cell 31 may be heated using a Peltier element instead of the heater 33 or in combination with the heater 33.
Such a heater 33 is electrically connected to a temperature control unit 62 of the control unit 6 described later and energized.

[Temperature sensor]
The temperature sensor 34 detects the temperature of the heater 33 or the gas cell 31. Based on the detection result of the temperature sensor 34, the amount of heat generated by the heater 33 is controlled. Thereby, the alkali metal atom in the gas cell 31 can be maintained at a desired temperature.
The installation position of the temperature sensor 34 is not particularly limited, and may be, for example, on the heater 33 or on the outer surface of the gas cell 31.
The temperature sensor 34 is not particularly limited, and various known temperature sensors such as a thermistor and a thermocouple can be used.
Such a temperature sensor 34 is electrically connected to a temperature control unit 62 of the control unit 6 which will be described later via a wiring (not shown).

[coil]
The coil 35 has a function of generating a magnetic field when energized. Thereby, by applying a magnetic field to the alkali metal in the gas cell 31, a gap between different energy levels in which the alkali metal is degenerated can be widened by Zeeman splitting to improve resolution. As a result, the accuracy of the oscillation frequency of the atomic oscillator 1 can be increased.

The magnetic field generated by the coil 35 may be either a DC magnetic field or an AC magnetic field, or may be a magnetic field in which a DC magnetic field and an AC magnetic field are superimposed.
The coil 35 is provided so as to surround the gas cell 31.
Moreover, the coil 35 is comprised with the wiring pattern of the flexible wiring board rounded off by the cylinder shape.

And this flexible wiring board is closely_contact | adhered to the inner wall face of the 2nd package 36 by the restoring force or the elastic force in the state rounded and elastically deformed in the cylinder shape in the 2nd package 36 mentioned later.
As a result, when the coil 35 is installed in the second package 36 when the second unit 3 is manufactured, the coil 35 is attached to the inner wall surface of the second package 36 by the restoring force or elastic force of the flexible wiring board rolled into a cylindrical shape. Can be brought into close contact (pressed). Therefore, the coil 35 can be brought into close contact with the inner wall surface of the second package 36 relatively easily and reliably. In addition, since it is not necessary to provide a member for supporting the coil 35 inside the coil 35, the degree of freedom in designing a member (for example, the gas cell 31) disposed inside the coil 35 can be increased.

The method for forming the coil 35 will be specifically described. First, a flexible wiring board 7 as shown in FIG. 8 is prepared.
The flexible wiring board 7 has an insulator layer 351 and a plurality of wires 352 (wiring patterns) formed on the insulator layer 351.
The insulator layer 351 has a rectangular shape or a band shape. That is, the flexible wiring board 7 for forming the coil 35 has a rectangular shape in plan view when deployed in the original shape.

Each of the plurality of wirings 352 extends along the longitudinal direction of the insulating layer 351 (that is, the longitudinal direction of the flexible wiring board 7 developed into the original shape). The plurality of wirings 352 are arranged so as to be parallel to each other. Thereby, the coil 35 can be easily formed only by rounding the flexible wiring board 7.
In the present embodiment, each wiring 352 extends in a direction slightly inclined with respect to the long side (side extending in the longitudinal direction) of the insulator layer 351. Thereby, by rounding the flexible wiring board 7 into a cylindrical shape, one end and the other end of the plurality of wirings 352 are connected in a state of being shifted one by one, and the coil 35 can be formed.
In addition, the flexible wiring board 7 has a connection portion 381 that connects to the substrate 38 on which the gas cell 31, the light receiving element 32, and the heater 33 are installed.
The substrate 38 is housed in the second package 36 together with the flexible wiring substrate 7.

The substrate 38 is a rigid substrate and is formed integrally with the flexible wiring substrate 7. That is, the flexible wiring board 7 and the board 38 are constituted by a rigid flexible wiring board having the flexible wiring board 7 as a flexible portion and the substrate 38 as a rigid portion.
Thereby, the flexible wiring board 7 for forming the coil 35 and the board | substrate 38 for installing the gas cell 31 can be formed simultaneously. Moreover, when assembling the 2nd unit 3, the effort which connects these board | substrates can be saved. In addition, the connection reliability can be improved.

Next, as shown in FIG. 9, the flexible wiring board 7 is rolled into a cylindrical shape by overlapping both end portions of the insulator layer 351 in the longitudinal direction.
Thereafter, the tubular flexible wiring board 7 is inserted into a second package 36 described later, and the flexible wiring board 7 is applied to the inner wall surface of the second package 36 by a restoring force that the flexible wiring board 7 returns to the original shape. Adhere closely.

At this time, if necessary, the degree of adhesion of the flexible wiring board 7 to the inner wall surface of the second package 36 may be increased using a jig, air blowing, or the like.
Then, in a state where the flexible wiring board 7 is in close contact with the inner wall surface of the second package 36, one end and the other end in the longitudinal direction of the insulator layer 351 are fixed to each other, and one end of the plurality of wirings 352 is fixed. And the other end are electrically connected in a state of being shifted one by one. Thereby, the coil 35 is formed.
The fixing of the insulator layer 351 and the connection of the wiring 352 are not particularly limited, and can be performed using, for example, solder, an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

  The constituent material of the insulator layer 351 of the flexible wiring board 7 (flexible part) is not particularly limited as long as it is a material that has high insulation and can impart flexibility to the flexible wiring board 7. Resin materials such as polyimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), aromatic polyester (liquid crystal polymer), and aromatic polyamide may be used alone or in combination of two or more. it can.

  The average thickness of the insulator layer 351 is not particularly limited, but is preferably 5 to 100 μm, and more preferably 10 to 50 μm. As a result, the flexible wiring board 7 is elastic so as to have good adhesion to the inner wall surface of the second package 36 when it is installed in the second package 36 to be described later while ensuring necessary insulation and flexibility. It will have.

Moreover, as a constituent material of each wiring 352 (wiring pattern) of the flexible wiring board 7, if it has electroconductivity, it will not specifically limit, For example, various types, such as copper, a copper-type alloy, aluminum, an aluminum-type alloy, etc. Examples include metals and various alloys. Among them, it is preferable to use copper and a copper-based alloy because it is excellent in electric conductivity and inexpensive.
The substrate 38 (rigid portion) has a first layer integrally formed with the flexible wiring substrate 7 described above, and a second layer laminated on the first layer.

The first layer is made of the same material as the flexible wiring board 7 described above.
The second layer is not particularly limited, but it is preferable that the second layer mainly includes a fibrous core material (fiber base material), a resin material, and an inorganic filler. As a result, the rigidity of the substrate 38 can be improved, and the thermal expansion coefficient of the substrate 38 can be reduced.
Examples of the core material included in the second layer of the substrate 38 include a glass fiber base material composed of glass fibers such as glass woven fabric and glass nonwoven fabric, polyamide resin fibers, aromatic polyamide resin fibers, and wholly aromatic polyamides. Polyamide resin fiber such as resin fiber, polyester resin fiber, aromatic polyester resin fiber, polyester resin fiber such as wholly aromatic polyester resin fiber, polyimide resin fiber, woven fabric or nonwoven fabric mainly composed of fluororesin fiber Examples thereof include a synthetic fiber base material, a kraft paper, a cotton linter paper, and a paper base material mainly composed of linter and kraft pulp mixed paper. Among these, a glass fiber base material is preferable from the viewpoint of improving the rigidity of the substrate 38 and reducing the thermal expansion coefficient.

Although it does not specifically limit as a resin material contained in the board | substrate 38, For example, it is preferable that a thermosetting resin is included. Thereby, the heat resistance of the substrate 38 can be improved.
Examples of such thermosetting resins include novolak type phenol resins such as phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, unmodified resol phenol resin, oil modified resole modified with tung oil, linseed oil, walnut oil, and the like. Phenol resin such as phenolic resin, bisphenol type epoxy resin such as bisphenol A epoxy resin, bisphenol F epoxy resin, novolac epoxy resin, novolac epoxy resin such as cresol novolac epoxy resin, biphenyl type epoxy resin, etc. Epoxy resin, cyanate resin, urea (urea) resin, resin having triazine ring such as melamine resin, unsaturated polyester resin, bismaleimide resin, polyurethane resin, diallyl phthalate Over preparative resin, silicone resin, resins having a benzoxazine ring, cyanate ester resins.

Note that the second layer of the substrate 38 may contain a thermoplastic resin such as a phenoxy resin, a polyimide resin, a polyamideimide resin, a polyphenylene oxide resin, or a polyethersulfone resin.
Examples of the inorganic filler contained in the second layer of the substrate 38 include talc, alumina, glass, silica, mica, aluminum hydroxide, and magnesium hydroxide. Among these, silica is preferable because of its low coefficient of thermal expansion, and fused silica (particularly spherical fused silica) is preferable.
Such a coil 35 is electrically connected to a magnetic field control unit 63 of the control unit 6 to be described later via a wiring (not shown). Thereby, the coil 35 can be energized.

[Second package]
The second package 36 houses the gas cell 31, the light receiving element 32, the heater 33, the temperature sensor 34, and the coil 35 described above.
The second package 36 is configured in the same manner as the first package 22 of the first unit 2 described above.

Specifically, as shown in FIG. 6, the second package 36 includes a base 361 (second base) and a lid 362 (second lid).
The base 361 directly or indirectly supports the gas cell 31, the light receiving element 32, the heater 33, the temperature sensor 34, and the coil 35. In the present embodiment, the base body 361 has a plate shape, and has a circular shape in plan view.

The gas cell 31, the light receiving element 32, and the heater 33 (a plurality of mounting parts) are installed (mounted) on one surface (mounting surface) of the base 361. In the present embodiment, the gas cell 31, the light receiving element 32, and the heater 33 are mounted on the base 361 through the substrate 38 described above.
Further, as shown in FIG. 5, a plurality of leads 363 protrude from the other surface of the base 361. The plurality of leads 363 are electrically connected to the light receiving element 32, the heater 33, the temperature sensor 34, and the coil 35 through a wiring (not shown).

A lid 362 that covers the gas cell 31, the light receiving element 32, the heater 33, the temperature sensor 34, and the coil 35 on the base 361 is joined to the base 361.
The lid body 362 has a bottomed cylindrical shape with one end opened.
In the present embodiment, the cylindrical part of the lid 362 has a cylindrical shape. That is, the inner wall surface of the second package 36 has a cylindrical shape. As a result, the coil 35 can be brought into close contact with the inner wall surface of the second package 36 easily and reliably.

The opening at one end of the lid 362 is closed by the base 361 described above.
A window 37 is provided at the other end of the lid 362, that is, at the bottom opposite to the opening of the lid 362.
The window portion 37 is provided on the optical axis a between the gas cell 31 and the light emitting element 21.
And the window part 37 has transparency with respect to the excitation light mentioned above.
In this embodiment, the window part 37 is comprised with the plate-shaped member which has a light transmittance.

The window portion 37 is not limited to a light-transmitting plate member as long as it has transparency to excitation light. For example, the window portion 37 is an optical component such as a lens, a polarizing plate, or a λ / 4 wavelength plate. May be.
The constituent material other than the window portion 37 of the lid 362 is not particularly limited, and for example, ceramic, metal, resin, or the like can be used.
Among these, as a constituent material of the cover 362 other than the window portion 37 (a constituent material of the second package 36), it is preferable to use a magnetic material, and it is more preferable to use a soft magnetic material. Thereby, the magnetic field generated by the coil 35 can be efficiently guided to the gas cell 31.

  Here, when the portion other than the window portion 37 of the lid 362 is made of a material that is transparent to excitation light, the portion other than the window portion 37 of the lid 362 and the window portion 37 are formed integrally. can do. Moreover, when parts other than the window part 37 of the cover body 362 are comprised with the material which does not have a transmittance | permeability with respect to excitation light, parts other than the window part 37 and the window part 37 of the cover body 362 are separated. These may be formed and bonded by a known bonding method.

The base 361 and the lid 362 are preferably joined in an airtight manner. That is, it is preferable that the inside of the second package 36 is an airtight space. Thereby, the inside of the 2nd package 36 can be made into a pressure reduction state or an inert gas enclosure state, As a result, the characteristic of the atomic oscillator 1 can be improved.
The method for joining the base 361 and the lid 362 is not particularly limited, and for example, brazing, seam welding, energy beam welding (laser welding, electron beam welding, etc.), and the like can be used.

Note that a bonding member for bonding them may be interposed between the base 361 and the lid 362.
Further, at least the gas cell 31 and the light receiving element 32 need only be accommodated in the second package 36, and components other than the gas cell 31, the light receiving element 32, the heater 33, the temperature sensor 34, and the coil 35 described above are accommodated. May be.

According to the second package 36 having the base 361 and the lid 362 as described above, the gas cell 31 and the light receiving element are allowed while allowing the excitation light from the light emitting element 21 to enter the second package 36. 32 can be stored in the second package 36. Therefore, by using the second package 36 in combination with the first package 22 as described above, the light emitting element 21 and the gas cell are secured while securing the optical path of the excitation light from the light emitting element 21 to the light receiving element 32 via the gas cell 31. 31 can be stored in separate packages that are not in contact with each other.
The second package 36 is held by a holding member 5 described later so that the base 361 is disposed on the side opposite to the first package 22.

(Optical parts)
A plurality of optical components 41, 42, 43 are arranged between the first package 22 and the second package 36 as described above. The plurality of optical components 41, 42, and 43 are provided on the optical axis a between the light emitting element 21 in the first package 22 and the gas cell 31 in the second package 36 described above, respectively. .

In this embodiment, the optical component 41, the optical component 42, and the optical component 43 are arranged in this order from the first package 22 side to the second package 36 side.
The optical component 41 is a λ / 4 wavelength plate. Thereby, for example, when the excitation light from the light emitting element 21 is linearly polarized light, the excitation light can be converted into circularly polarized light (right circularly polarized light or left circularly polarized light).

  As described above, in the state where the alkali metal atoms in the gas cell 31 are Zeeman split by the magnetic field of the coil 35, if the alkali metal atoms are irradiated with excitation light of linearly polarized light, the interaction between the excitation light and the alkali metal atoms causes an alkali. This means that metal atoms are evenly distributed in a plurality of levels where Zeeman splits. As a result, the number of alkali metal atoms at a desired energy level is relatively small with respect to the number of alkali metal atoms at other energy levels, so that the number of atoms that develop a desired EIT phenomenon is reduced and desired. As a result, the oscillation characteristic of the atomic oscillator 1 is deteriorated.

  On the other hand, when the alkali metal atom is irradiated with the circularly polarized excitation light in the state where the alkali metal atom in the gas cell 31 is Zeeman split by the magnetic field of the coil 35 as described above, the interaction between the excitation light and the alkali metal atom. Thus, the number of alkali metal atoms having a desired energy level among the plurality of levels in which the alkali metal atom is Zeeman split can be relatively increased with respect to the number of alkali metal atoms having other energy levels. . Therefore, the number of atoms that express the desired EIT phenomenon increases and the desired EIT signal increases, and as a result, the oscillation characteristics of the atomic oscillator 1 can be improved.

  In the present embodiment, the optical component 41 has a disk shape. Therefore, the optical component 41 can be rotated around an axis parallel to the optical axis a while being engaged with a groove 511 having a shape as described later. In addition, the planar view shape of the optical component 41 is not limited to this, For example, depending on the cross-sectional shape of the recessed part 51 of the holding member 5 mentioned later, you may comprise polygons, such as a rectangle and a pentagon.

Optical components 42 and 43 are arranged on the second unit 3 side with respect to such an optical component 41.
Each of the optical components 42 and 43 is a neutral density filter (ND filter). As a result, the intensity of the excitation light LL incident on the gas cell 31 can be adjusted (decreased). Therefore, even when the output of the light emitting element 21 is large, the excitation light incident on the gas cell 31 can be set to a desired light amount. In the present embodiment, the optical components 42 and 43 adjust the intensity of the excitation light converted into circularly polarized light by the optical component 41 described above.

In the present embodiment, the optical components 42 and 43 each have a plate shape. Moreover, the planar view shapes of the optical components 42 and 43 are each rectangular.
In addition, the planar view shape of the optical components 42 and 43 is not limited to this, For example, you may comprise circular. When the planar view shape of the optical components 42 and 43 is circular, the optical components 42 and 43 can be rotated around an axis parallel to the optical axis a while being engaged with grooves 512 and 513 having shapes as described later. it can.

The optical component 42 and the optical component 43 may have the same or different dimming ratio.
Moreover, the optical components 42 and 43 may have portions where the light attenuation rates are different continuously or stepwise on the upper side and the lower side, respectively. In this case, the attenuation ratio of the excitation light can be adjusted by adjusting the positions of the optical components 42 and 43 in the vertical direction with respect to the holding member 5.

In addition, when the optical components 42 and 43 are rotatable about the axis parallel to the optical axis a in a state where the optical components 42 and 43 are engaged with the grooves 512 and 513, the optical components 42 and 43 are continuously or intermittently in the circumferential direction, respectively. May have portions having different light attenuation rates. In this case, the attenuation ratio of the excitation light can be adjusted by rotating the optical components 42 and 43.
One of the optical components 42 and 43 may be omitted. Moreover, when the output of the light emitting element 21 is moderate, both of the optical components 42 and 43 can be omitted.

(Holding member)
The holding member 5 has a function of holding the first package 22, the second package 36, and the plurality of optical components 41, 42, 43 described above.
The holding member 5 holds the first package 22 and the second package 36 without contacting each other.
Thereby, thermal interference between the light emitting element 21 and the gas cell 31 can be prevented or suppressed, and the temperature control of the light emitting element 21 and the gas cell 31 can be independently performed with high accuracy.

If it demonstrates concretely, as shown in FIG. 5, the holding member 5 has the recessed part 51 opened to upper side.
In the recess 51, the first package 22, the second package 36, and a plurality of optical components 41, 42, and 43 are installed. In the present embodiment, the lower portions of the first package 22, the second package 36, and the plurality of optical components 41, 42, 43 are respectively located in the recesses 51.

  The recess 51 has a shape that regulates the positions and postures of the first package 22 and the second package 36. Thereby, the optical system including the light emitting element 21 and the light receiving element 32 can be positioned by installing the first package 22 and the second package 36 in the recess 51 of the holding member 5. Therefore, the installation of the first package 22 and the second package 36 with respect to the holding member 5 can be facilitated.

Here, the recess 51 extends in the X-axis direction, the first package 22 is disposed on one end side (left side in FIG. 5), and on the other end side (right side in FIG. 5). The second package 36 is disposed.
In addition, the first package 22 and the second package 36 are arranged so that the axis of the cylindrical lid body 222 and the lid body 362 are parallel to the extending direction of the recess 51 (X-axis direction). Thereby, the first package 22 and the second package 36 are arranged such that the axes of the lid 222 and the lid 362 are aligned or parallel to each other.

In this embodiment, the cross section of the recess 51 is rectangular.
Further, a support portion 52 (first support portion) that supports the base 221 of the first package 22 is provided on one end portion side (left side in FIG. 5) of the holding member 5, and the other end portion ( On the right side in FIG. 5, a support portion 53 (second support portion) that supports the base body 361 of the second package 36 is provided.

  As described above, the support portion 52 supports the base body 221 and the support portion 53 supports the base body 361, so that the contact portion between the first package 22 and the holding member 5, the second package 36, and the holding member 5 The distance from the contact portion can be increased. Therefore, heat conduction through the holding member 5 between the first package 22 and the second package 36 can be more effectively suppressed.

  Further, the lid body 222 and the lid body 362 are not in contact with the holding member 5. Thereby, the heat conduction through the holding member 5 between the first package 22 and the second package 36 can be more effectively suppressed. In particular, the cross section of the recess 51 is rectangular, whereas the cylindrical portions of the lids 222 and 362 are respectively cylindrical, so that the comparison is made between the side surfaces of the lids 222 and 362 and the holding member 5. Large gaps can be formed. As a result, heat conduction from the lids 222 and 362 to the holding member 5 can be suppressed to an extremely low level. Even if the side surfaces of the lids 222 and 362 and the holding member 5 are in contact with each other, the contact area can be reduced.

  Here, the support part 52 has an installation surface parallel to the Y axis and the Z axis. The surface opposite to the lid 222 of the base body 221 of the first package 22 is in contact with or close to the installation surface. Thereby, the position and attitude | position of the 1st package 22 with respect to the holding member 5 can be controlled. The base body 221 can be fixed to the support portion 52 using an adhesive, for example.

  Further, the support portion 52 is formed with a plurality of through holes 521 through which the plurality of leads 223 of the first package 22 described above are inserted. That is, the support part 52 has a shape like a socket to which the first package 22 is attached. Also by this, the position and posture of the first package 22 with respect to the holding member 5 can be regulated. The plurality of leads 223 can be fixed to the support portion 52 with, for example, solder.

The plurality of leads 223 are inserted into the plurality of through-holes 521, and a plurality of wirings (not shown) are connected to a plurality of terminals (not shown) provided on the lower surface or side surface of the outer surface of the holding member 5. Electrically connected.
Similarly, the support part 53 has an installation surface parallel to the Y axis and the Z axis. The surface opposite to the lid 362 of the base body 361 of the second package 36 is in contact with or close to this installation surface. Thereby, the position and attitude | position of the 2nd package 36 with respect to the holding member 5 can be controlled. Note that the base 361 can be fixed to the support 53 using an adhesive, for example.

  Further, the support portion 53 is formed with a plurality of through holes 531 through which the plurality of leads 363 of the second package 36 described above are inserted. That is, the support portion 53 has a shape like a socket to which the second package 36 is attached. Also by this, the position and posture of the second package 36 with respect to the holding member 5 can be regulated. The plurality of leads 363 can be fixed to the support portion 53 by, for example, solder.

Further, the plurality of leads 363 are inserted into the plurality of through holes 531, whereby a plurality of wires (not shown) are connected to a plurality of terminals (not shown) provided on the lower surface or the side surface of the outer surface of the holding member 5. ) Through an electrical connection.
As described above, the holding member 5 holds the first package 22 and the second package 36.

Further, as described above, the holding member 5 holds the optical components 41, 42, and 43, respectively. Thereby, when attaching each component to the holding member 5 at the time of manufacturing the atomic oscillator 1, the optical components 41, 42, and 43 are moved to their positions or in a state where the first package 22 and the second package 36 are held by the holding member 5. It can be installed on the holding member 5 while adjusting its posture.
Specifically, a groove 511 that holds the optical component 41, a groove 512 that holds the optical component 42, and a groove 513 that holds the optical component 43 are formed on the wall surface of the recess 51 of the holding member 5. Yes.

  In the present embodiment, the grooves 511, 512, and 513 are formed so that the plate surfaces of the optical components 41, 42, and 43 are parallel to each other. The grooves 511, 512, and 513 are formed such that the plate surfaces of the optical components 41, 42, and 43 are perpendicular to the optical axis a. The grooves 511, 512, and 513 may be formed such that the plate surfaces of the optical components 41, 42, and 43 are not parallel to each other, and the plate surfaces of the optical components 41, 42, and 43 are respectively optical axes a. It may be formed so as to be inclined with respect to.

The groove 511 can rotatably hold the optical component 41 around an axis (for example, the optical axis a) along a line segment connecting the first package 22 and the second package 36. Accordingly, the posture of the optical component 41 around the optical axis a can be adjusted in a state where the optical component 41 is engaged with the groove 511 of the holding member 5 and positioned in a direction parallel to the optical axis a.
Here, as described above, since the optical component 41 is a λ / 4 wavelength plate, the light emitting element 21 is adjusted by adjusting the posture of the optical component 41 by rotation, regardless of the posture of the first package 22 with respect to the holding member 5. Can be converted from linearly polarized light to circularly polarized light.

Further, since the optical component 41 has a disk shape, the optical component 41 comes into contact with the wall surface of the concave portion 51 having a rectangular cross section at three places. Thereby, the optical component 41 can be positioned with respect to the holding member 5.
When installing the optical components 41, 42, 43 on the holding member 5, for example, first, the first unit 2 and the second unit 3 are first installed and fixed on the holding member 5. After that, with the optical components 41, 42, 43 engaged with the corresponding grooves 511, 512, 513, while checking the EIT signal, etc., the position and orientation of each optical component 41, 42, 43 Change at least one. When the desired EIT signal is confirmed, the optical components 41, 42, 43 are fixed to the holding member 5 in that state. Such fixing is not particularly limited, but for example, it is preferable to use a photocurable adhesive. The photo-curing adhesive can change the position or posture of each optical component 41, 42, 43 even if it is supplied to each groove 511, 512, 513 before curing, and in a short time when desired. Can be fixed by curing.

The holding member 5 is preferably made of a nonmetal such as a resin material or a ceramic material.
Thereby, the heat conduction through the holding member 5 between the first package 22 and the second package 36 can be suppressed. As a result, thermal interference between the light emitting element 21 and the gas cell 31 can be effectively prevented or suppressed.

  Although it does not specifically limit as resin material which comprises the holding member 5, For example, polyolefin, such as polyethylene and ethylene-vinyl acetate copolymer (EVA), acrylic resin, acrylonitrile-butadiene-styrene copolymer (ABS resin) , Acrylonitrile-styrene copolymer (AS resin), polyethylene terephthalate (PET), polyether, polyether ketone (PEK), polyether ether ketone (PEEK), styrene, polyolefin, polyvinyl chloride, polyurethane, Various thermoplastic elastomers such as polyester, polyamide, polybutadiene, trans polyisoprene, fluoro rubber, and chlorinated polyethylene, epoxy resin, phenol resin, urea resin, melamine resin, unsaturated polyester, Examples thereof include corn resin, polyurethane and the like, and copolymers, blends, polymer alloys and the like mainly containing these, and one or more of these are used in combination (for example, as a laminate of two or more layers). be able to.

  Further, the ceramic material constituting the holding member 5 is not particularly limited. For example, various glasses, and oxide ceramics such as alumina, silica, titania, zirconia, yttria, calcium phosphate, silicon nitride, aluminum nitride, Nitride ceramics such as titanium nitride and boron nitride; carbide ceramics such as graphite and tungsten carbide; and other ferroelectric materials such as barium titanate, strontium titanate, PZT, PLZT, and PLLZT .

In addition, the thermal conductivity of the holding member 5 is preferably 0.1 W · m ⁻¹ · K ⁻¹ or more and 40 W · m ⁻¹ · K ⁻¹ or less, and 0.1 W · m ⁻¹ · K ^−1. More preferably, it is 0.5 W · m ⁻¹ · K ⁻¹ or less. Thereby, the heat conduction through the holding member 5 between the first package 22 and the second package 36 can be more effectively suppressed. That is, the heat insulating property of the holding member 5 can be improved, and the effect of thermally separating the first package 22 and the second package 36 can be made remarkable.

  On the other hand, when the thermal conductivity is too low, it is difficult to select a material that can secure the rigidity necessary for the holding member 5 depending on the shape, size, and the like of the holding member 5, while the thermal conductivity is too high. In this case, depending on the distance between the contact portion between the first package 22 and the holding member 5 and the contact portion between the second package 36 and the holding member 5, the holding member 5 between the first package 22 and the second package 36. It is difficult to suppress heat conduction through

[Control unit]
The control unit 6 illustrated in FIG. 2 has a function of controlling the heater 33, the coil 35, and the light emitting element 21, respectively.
Such a control unit 6 is applied to the excitation light control unit 61 that controls the frequencies of the resonant lights 1 and 2 of the light emitting element 21, the temperature control unit 62 that controls the temperature of the alkali metal in the gas cell 31, and the gas cell 31. A magnetic field control unit 63 that controls the magnetic field to be generated.

  The excitation light control unit 61 controls the frequencies of the resonant lights 1 and 2 emitted from the light emitting element 21 based on the detection result of the light receiving element 32 described above. More specifically, the excitation light control unit 61 uses the resonance light emitted from the light emitting element 21 so that (ω1-ω2) detected by the light receiving element 32 described above becomes the frequency ω0 unique to the alkali metal described above. Control the frequency of 1 and 2. In addition, the excitation light control unit 61 controls the center frequency of the resonant lights 1 and 2 emitted from the light emitting element 21.

Further, the temperature control unit 62 controls energization to the heater 33 based on the detection result of the temperature sensor 34. Thereby, the gas cell 31 can be maintained within a desired temperature range. Here, the temperature sensor 34 constitutes temperature detection means for detecting the temperature of the gas cell 31.
The magnetic field control unit 63 controls energization of the coil 35 so that the magnetic field generated by the coil 35 is constant.
Such a control part 6 is provided in the IC chip mounted on the board | substrate with which the holding member 5 is installed, for example.

According to the atomic oscillator 1 of this embodiment as described above, when the coil 35 is installed in the second package 36 when the second unit 3 is manufactured, the restoring force of the flexible wiring board 7 rolled into a cylindrical shape or The coil 35 can be brought into close contact with the inner wall surface of the second package 36 by the elastic force. Therefore, the coil 35 can be brought into close contact with the inner wall surface of the second package 36 relatively easily and reliably. In addition, since it is not necessary to provide a member for supporting the coil 35 inside the coil 35, the degree of freedom in designing the member disposed inside the coil 35 can be increased.
Further, by providing such a second unit 3, it is possible to exhibit excellent oscillation characteristics.

Second Embodiment
Next, a second embodiment of the present invention will be described.
FIG. 10 is a cross-sectional view showing a gas cell unit according to the second embodiment of the present invention.
The gas cell unit according to the present embodiment is the same as the atomic oscillator according to the first embodiment described above except that the shape of the package that houses the gas cell and the coil is different.

In the following description, the gas cell unit of the second embodiment will be described with a focus on differences from the first embodiment, and the description of the same matters will be omitted. In FIG. 10, the same reference numerals are given to the same configurations as those in the above-described embodiment.
The second unit 3A (gas cell unit) shown in FIG. 10 includes a second package 36A that houses the gas cell 31 and the coil 35A.

The second package 36 includes a lid 362A having a cylindrical portion that forms a square cylindrical shape.
The coil 35A is configured with a wiring pattern of a flexible wiring board, like the coil 35 of the first embodiment described above, and the flexible wiring board is rounded into a cylindrical shape, and its lid is restored by its restoring force or elastic force. The body 362A is in close contact with the inner peripheral surface.
Even in the second unit 3A (gas cell unit) according to the second embodiment as described above, a member for supporting the coil 35A is not provided inside the coil 35A. The coil 35A can be easily and reliably adhered to the peripheral surface.

<Third Embodiment>
Next, a third embodiment of the present invention will be described.
FIG. 11 is a longitudinal sectional view showing a gas cell unit according to the third embodiment of the present invention.
The gas cell unit (atomic oscillator) according to the present embodiment is the same as the gas cell unit (atomic oscillator) according to the first embodiment described above except that a gas cell, a coil, and the like are housed in a package together with a light emitting element and the like.

In the following description, the gas cell unit of the third embodiment will be described with a focus on differences from the first embodiment, and description of similar matters will be omitted. In FIG. 11, the same reference numerals are given to the same configurations as those in the above-described embodiment.
An atomic oscillator 1B (gas cell unit) shown in FIG. 11 has a package 22B.
The package 22B houses the light emitting element 21, the Peltier element 24, the gas cell 31, the light receiving element 32, the heater 33, and the coil 35B.
The package 22B includes a base body 221 and a lid body 222B.

Here, the gas cell 31, the light receiving element 32, and the heater 33 are supported by the base 221 through a support member 8 for forming a gap with the light emitting element 21.
Similarly to the coil 35 of the first embodiment described above, the coil 35B is composed of a wiring pattern of a flexible wiring board, and the flexible wiring board is rounded into a cylindrical shape, and the restoring force or elastic force is used to cover the coil 35B. The body 222B is in close contact with the inner peripheral surface.
Even with the atomic oscillator 1B (gas cell unit) according to the third embodiment as described above, a member for supporting the coil 35B is not provided on the inner side of the coil 35B. The coil 35B can be brought into close contact easily and reliably.

(Electronics)
The atomic oscillator as described above can be incorporated into various electronic devices. Such an electronic device has excellent reliability.
Hereinafter, the electronic apparatus of the present invention will be described.
FIG. 12 is a diagram showing a schematic configuration when the atomic oscillator of the present invention is used in a positioning system using a GPS satellite.

The positioning system 100 shown in FIG. 12 includes a GPS satellite 200, a base station device 300, and a GPS receiver 400.
The GPS satellite 200 transmits positioning information (GPS signal).
The base station device 300 receives the positioning information from the GPS satellite 200 with high accuracy via, for example, an antenna 301 installed at an electronic reference point (GPS continuous observation station), and the reception device 302 receives the positioning information. And a transmission device 304 that transmits positioning information via the antenna 303.

Here, the receiving device 302 is an electronic device provided with the above-described atomic oscillator 1 of the present invention as its reference frequency oscillation source. Such a receiving apparatus 302 has excellent reliability. In addition, the positioning information received by the receiving device 302 is transmitted by the transmitting device 304 in real time.
The GPS receiver 400 includes a satellite receiver 402 that receives positioning information from the GPS satellite 200 via the antenna 401, and a base station receiver 404 that receives positioning information from the base station device 300 via the antenna 403. Prepare.

FIG. 13 is a schematic configuration diagram showing an example of a clock transmission system using the atomic oscillator of the present invention.
A clock transmission system 500 shown in FIG. 13 matches the clocks of the devices in the time division multiplexing network and has a redundant configuration of N (Normal) and E (Emergency) systems.

The clock transmission system 500 includes a clock supply device (CSM: Clock Supply Module) 501 and an SDH (Synchronous Digital Hierarchy) device 502 of station A (upper (N system)), and a clock of station B (upper (E system)). A supply device 503 and an SDH device 504, and a clock supply device 505 and SDH devices 506 and 507 of a station C (lower level) are provided.
The clock supply device 501 has an atomic oscillator 1 and generates an N-system clock signal. The atomic oscillator 1 in the clock supply device 501 generates a clock signal in synchronization with higher-precision clock signals from master clocks 508 and 509 including an atomic oscillator using cesium.

The SDH device 502 transmits and receives the main signal based on the clock signal from the clock supply device 501, superimposes the N-system clock signal on the main signal, and transmits it to the lower clock supply device 505.
The clock supply device 503 includes the atomic oscillator 1 and generates an E-system clock signal. The atomic oscillator 1 in the clock supply device 503 generates a clock signal in synchronization with higher-precision clock signals from master clocks 508 and 509 including an atomic oscillator using cesium.

The SDH device 504 transmits and receives the main signal based on the clock signal from the clock supply device 503, superimposes the E-system clock signal on the main signal, and transmits it to the lower clock supply device 505.
The clock supply device 505 receives the clock signals from the clock supply devices 501 and 503, and generates a clock signal in synchronization with the received clock signals.

Here, the clock supply device 505 normally generates a clock signal in synchronization with the N-system clock signal from the clock supply device 501. When an abnormality occurs in the N system, the clock supply device 505 generates a clock signal in synchronization with the E system clock signal from the clock supply device 503. By switching from the N system to the E system in this way, stable clock supply can be ensured and the reliability of the clock path network can be improved.
The SDH device 506 transmits and receives the main signal based on the clock signal from the clock supply device 505. Similarly, the SDH device 507 transmits and receives the main signal based on the clock signal from the clock supply device 505. As a result, the C station apparatus can be synchronized with the A station or B station apparatus.

As mentioned above, although the gas cell unit, atomic oscillator, and electronic device of this invention were demonstrated based on embodiment of illustration, this invention is not limited to these.
In the gas cell unit, atomic oscillator, and electronic device of the present invention, the configuration of each part can be replaced with any configuration that exhibits the same function, and any configuration can be added.

Moreover, you may make it combine the arbitrary structures of each embodiment mentioned above with the gas cell unit and atomic oscillator of this invention.
In the above-described embodiment, the case where the coil is provided by being wound around the outer periphery of the gas cell so as to constitute a solenoid type has been described as an example. However, the form of the coil is not limited to this, for example, The wiring pattern of the flexible wiring board rolled into a cylindrical shape may constitute a pair of coils facing each other through a gas cell so as to constitute a Helmholtz type.

  DESCRIPTION OF SYMBOLS 1 ... Atomic oscillator 1B ... Atomic oscillator 2 ... 1st unit 2B ... Package 3 ... 2nd unit 3A ... 2nd unit 7 ... Flexible wiring board 8 ... Supporting member 21 ... Light emitting element 22 ... First package 22B Package 23 Window 24 Peltier element 31 Gas cell 32 Light receiving element 33 Heater 34 Temperature sensor 35 Coil 35A Coil 35B Coil 36 2nd package 36A 2nd package 37 Window portion 38 Substrate 41 Optical component 42 Optical component 43 Optical component 5 Holding member 51 Recessed portion 52 Supporting portion 53 ··· Supporting unit 6 ··· Control unit 61 ··· Excitation light control unit 62 · · · Temperature control unit 63 · · · Magnetic field control unit 100 · · · Positioning system 20 ... Satellite 221 ... Base 222 ... Lid 222B ... Lid 223 ... Lead 300 ... Base station 301 ... Antenna 302 ... Receiving device 303 ... Antenna 304 ... Transmitter 311 ... Main unit 312 ... Window 313 ... Window 331 ... Heating resistor 332 ... Heating resistor 351 ... Insulator layer 352 ... Wiring 361 ... Base 362 ... Lid 362A ... Lid 363 ... Lead 381 ··· Connection unit 400 ··· Reception device 401 ··· Antenna 402 ··· Satellite reception unit 403 · · · Antenna 404 · · · Base station reception unit 500 · · · Clock transmission system 501 · · · Clock supply device 502 · · · SDH device 503 ··· ... Clock supply device 504 ... SDH device 505 ... Clock supply device 506 ... SDH device 50 7 ... SDH equipment 508 ... Master clock 509 ... Master clock 511 ... Groove 512 ... Groove 513 ... Groove 521 ... Through hole 531 ... Through hole a ... Optical axis LL ... Excitation light S ... Internal space ω0 ...... Frequency ω1 ...... Frequency ω2 ...... Frequency

Claims (8)

A gas cell in which gaseous metal atoms are enclosed;
A coil that is provided around the gas cell and is configured by a wiring pattern of a flexible wiring board;
A package for housing the gas cell and the coil,
The gas cell unit, wherein the flexible wiring board is rolled into a cylindrical shape in the package and pressed against an inner wall surface of the package by an elastic force of the flexible board.   The gas cell unit according to claim 1, wherein an inner wall surface of the package has a cylindrical shape.   The gas cell unit according to claim 1, wherein the package is made of a magnetic material.   The gas cell unit according to claim 3, wherein the magnetic material is a soft magnetic material. Further comprising a substrate housed in the package and provided with the gas cell;
The gas cell unit according to any one of claims 1 to 4, wherein the substrate is a rigid substrate and is formed integrally with the flexible wiring substrate. A gas cell unit according to any one of claims 1 to 5,
A light emitting element that emits excitation light that excites the gaseous metal atoms in the gas cell;
An atomic oscillator comprising: a light receiving element that is housed in the package and detects the excitation light transmitted through the gas cell. The light emitting element is disposed outside the package;
The atomic oscillator according to claim 6, wherein the package has a window portion that transmits the excitation light from the light emitting element.   An electronic apparatus comprising the atomic oscillator according to claim 6.

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