JP2011114181A - Atomic oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an atomic oscillator excelling in easiness of assembly, reduction of a mounting area, and vibration resistance. <P>SOLUTION: A physical package 20 includes: a lead frame (support member) 6 including lead terminals 8 for external connection; a Peltier element 5; a semiconductor laser (light source) 1 for generating a resonant light pair causing alkaline metal atoms to generate an electromagnetic induction transmission phenomenon; a cell 3 capsulating the alkaline metal atoms; a PD (photodetector) 4 for detecting the resonant light pair having passed through the alkaline metal atoms; and a thermistor (temperature detection element) 2 for detecting the temperature of the Peltier element 5. The physical package is structured such that the Peltier element 5 is mounted on the lead frame 6, the thermistor 2, the semiconductor laser 1, the cell 3 and the PD 4 are horizontally arranged side by side on the Peltier element 5, and the exposure surfaces of all the components mounted on the lead frame 6 are covered with a resin (sealing member) 7. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an atomic oscillator, and more particularly to a configuration of an atomic oscillator sealed by a sealing member.

An atomic oscillator using an alkali metal such as rubidium or cesium needs to keep the atoms in a gas state when utilizing the energy transition of the atoms. Therefore, the gas cell in which the atoms are hermetically sealed is operated at a constant temperature. ing. The principle of operation of an atomic oscillator is broadly divided into a double resonance method using light and microwaves, and a method using a quantum interference effect by two types of laser light. By detecting how much the gas is absorbed by the detector provided on the opposite side, the atomic resonance is detected, and the control system synchronizes a reference signal such as a crystal oscillator with this atomic resonance to obtain an output. Yes.
FIG. 8 is a schematic view of a physical package of a conventional atomic oscillator. As is apparent from this figure, the conventional physical package includes a Peltier element 106 and a semiconductor laser 10 as a light source.
5. Parallel lens 108 for converting laser light into parallel light;
The four-wavelength plates 109 and 110, the alkali metal atoms 115, the cell 100, and the photodetector 113 are stacked (see Patent Document 1).

US6320472B1

However, in the conventional technique disclosed in Patent Document 1, the temperature is controlled by using the Peltier element 106, the semiconductor laser 105, the cell 100, and the photodetector 113 as individual parts, and only the individual parts are arranged. Therefore, there is a problem that characteristics are not stable against vibration. There is also a problem that it is difficult to mount on a universal substrate.
The present invention has been made in view of such problems, and by molding the laser and the optical system part integrally with the Peltier element, the ease of assembly, the reduction of the mounting area,
It is another object of the present invention to provide an atomic oscillator having excellent vibration resistance.

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 support member having a lead terminal for external connection, a Peltier element, a light source for generating a resonant light pair that generates an electromagnetically induced transmission phenomenon in an alkali metal atom, and the alkali metal atom are encapsulated A cell, a light detection means for detecting the resonant light pair that has passed through the alkali metal atom, and a temperature detection element that detects the temperature of the Peltier element, and the support member includes the Peltier element, the light source, the cell, And a light detecting means are sequentially laminated to form a laminated body, and the laminated body and the exposed surface of the temperature detecting element are covered with a sealing member.

In the present invention, a Peltier element is installed on a support member, and a light source, a cell, and light detection means are sequentially stacked thereon. Further, the temperature detection element is disposed in the vicinity of the Peltier element. In this state, a vertically stacked atomic oscillator is configured. Since it is easily affected by vibration and the external environment as it is, the exposed surfaces of the laminate and the temperature detecting element are covered with a sealing member such as a resin. As a result, assembly is possible in units of support members, the mounting area is reduced, and a structure that is strong against vibration can be obtained.

Application Example 2 A support member having a lead terminal for external connection, a Peltier element, a light source for generating a resonant light pair that generates an electromagnetically induced transmission phenomenon in an alkali metal atom, and the alkali metal atom are encapsulated A cell, a light detection means for detecting the resonant light pair that has passed through the alkali metal atom, and a temperature detection element that detects the temperature of the Peltier element, and the support member includes the Peltier element and the temperature detection element. The light source, the cell, and the light detecting means are mounted on the Peltier element, and the exposed surfaces of all components mounted on the support member are covered with a sealing member.

In the present invention, the Peltier element and the temperature detection element are mounted on the support member, and the light source, the cell, and the light detection means are provided side by side so as to align the optical axis on the Peltier element. Since it is easily affected by vibration and the external environment, the exposed surfaces of all the components mounted on the support member are covered with a sealing member such as resin. As a result, the assembly can be performed in units of support members, the height can be reduced, and a structure resistant to vibration can be obtained.

Application Example 3 A configuration in which the Peltier element is excluded, and the light source, the cell, and the light detection unit are directly provided on the support member.

The Peltier element can control the temperature of the opposing surface by supplying current from the outside. However, the number of parts increases accordingly, which becomes an obstacle to downsizing.
Therefore, in the present invention, temperature control is performed externally except for the Peltier element. As a result, the atomic oscillator can be miniaturized and the cost can be reduced by reducing the number of parts.

[Application Example 4] A groove for forming the light source, the cell, and the light detection means is formed in the Peltier element or the support member.

When the light source, the cell, and the light detection means are arranged side by side, the most important thing is to align the optical axes. Therefore, in the present invention, the groove is formed so that the optical axis is aligned when each component is set in the groove. This eliminates the need for optical axis alignment, and can reduce inspection man-hours and manufacturing costs.

  Application Example 5 The sealing member is formed of a transparent member.

Generally, the resin that is a sealing member is black in order to block the influence of external light. For this reason, if the sealing member enters the gap between the connection portions of the light source, the cell, and the light detection means, there is a possibility that the light is hindered. Therefore, in the present invention, the sealing member itself is made of a transparent member. Thereby, even if the sealing member enters the gap of the connecting portion, the component can be sealed without hindering light.

Application Example 6 A transparent member fills a gap between the emission side of the light source and the incident side of the cell and a gap between the emission side of the cell and the incident side of the light detection means.

Generally, the resin that is a sealing member is black in order to block the influence of external light. For this reason, if the sealing member enters the gap between the connection portions of the light source, the cell, and the light detection means, there is a possibility that the light is hindered. Therefore, in the present invention, the gaps between the respective connecting portions are filled with a transparent member in advance, and then the whole is sealed with the sealing member. Thereby, it can prevent that a sealing member penetrate | invades in the clearance gap between a connection part, blocking external light.

Application Example 7 It is characterized in that the surface or inner layer of the sealing member is covered with at least one heat insulating member.

The light source or cell needs to be heated to a certain temperature. Therefore, it is important to prevent heat from escaping from the outside of the sealing member in order to increase thermal efficiency. Therefore, in the present invention, a heat insulating member is disposed on the surface or inner layer of the sealing member. The effect of this heat insulating member is enhanced by providing a plurality of layers. Thereby, the thermal efficiency of the heat source which heats a light source or a cell can be improved.

It is a figure which shows the structure of the physical package of the atomic oscillator which concerns on the 1st Embodiment of this invention, (a) is an internal side view, (b) is an internal top view, (c) is packaged with resin. It is an external view. It is a figure which shows the structure of the physical package of the atomic oscillator which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the physical package of the atomic oscillator which concerns on the 3rd Embodiment of this invention. It is a figure explaining the positioning groove | channel of the components formed in the Peltier device or the lead frame, (a) is a top view, (b) is AA sectional drawing. It is a flowchart explaining the process of manufacturing the atomic oscillator which concerns on embodiment of FIG. It is a figure which shows a mode that the physical package 20 of this invention was mounted on the board | substrate with the other IC chip. It is a figure which shows the structure of the physical package provided with the heat insulating material, (a) is the figure which provided the heat insulating material on the surface of resin, (b) is the figure which provided the heat insulating material of one layer inside the resin, (c) ) Is a diagram in which two layers of heat insulating material are provided inside the resin. It is the figure which modeled the physical package of the conventional atomic oscillator.

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 is a diagram showing a configuration of a physical package of an atomic oscillator according to the first embodiment of the present invention. FIG. 1A is an internal side view, FIG. 1B is an internal top view, and FIG. 1C is an external view packaged with resin. This physical package 20 has lead terminals 8 for external connection.
A lead frame (support member) 6 having a Peltier element 5, a semiconductor laser (light source) 1 for generating a resonant light pair for generating an electromagnetically induced transmission phenomenon in alkali metal atoms, and a cell in which alkali metal atoms are enclosed 3 and PD for detecting a resonant light pair transmitted through an alkali metal atom
(Photo Diode: light detection means) 4 and a thermistor (temperature detection element) 2 for detecting the temperature of the Peltier element 5, the Peltier element 5 is mounted on the lead frame 6, and the Peltier element 5
The thermistor 2, the semiconductor laser 1, the cell 3, and the PD 4 are arranged side by side, and the exposed surfaces of all the components mounted on the lead frame 6 are covered with a resin member (sealing member) 7. . As shown in FIG. 1B, when the semiconductor laser 1, the cell 3, and the PD 4 are arranged side by side, they are arranged so that the optical axes of the resonance lights emitted from the semiconductor laser 1 coincide. Then, by molding with the resin 7, as shown in FIG. 1C, it looks like a general IC chip from the appearance. The thermistor 2 may be located anywhere as long as it is in contact with the Peltier element 5.
Thus, in this embodiment, the Peltier element 5 and the thermistor 2 are mounted on the lead frame 6, and the semiconductor laser 1, the cell 3, and the PD 4 are arranged side by side so as to align the optical axis on the Peltier element 5. . Since it is easily affected by vibration and the external environment, the exposed surfaces of all components mounted on the lead frame 6 are covered with a sealing member such as resin. As a result, assembly can be performed in units of the lead frame 6, the height can be reduced, and a structure resistant to vibration can be obtained.

FIG. 2 is a diagram showing a configuration of a physical package of an atomic oscillator according to the second embodiment of the present invention. The same components will be described with the same reference numerals as in FIG. This physical package 21 is
A lead frame 6 having lead terminals 8 for external connection; a Peltier element 5; a semiconductor laser 1 for generating a resonant light pair that generates an electromagnetically induced transmission phenomenon in alkali metal atoms;
A cell 3 enclosing an alkali metal atom, a PD (Photo Diode: light detecting means) 4 for detecting a resonant light pair that has passed through the alkali metal atom, and a thermistor 2 for detecting the temperature of the Peltier element 5
A lead frame 6 with a Peltier element 5, a semiconductor laser 1, a cell 3, and a PD
4 was sequentially laminated to form a laminated body, and the laminated body and the exposed surface of the thermistor 2 were covered with a resin 7.
Thus, in this embodiment, the Peltier element 5 is installed on the lead frame 6, and the semiconductor laser 1, the cell 3, and the PD 4 are sequentially stacked thereon. Further, the thermistor 2 is disposed in the vicinity of the Peltier element 5. In this state, a vertically stacked atomic oscillator is configured. As it is, the laminated body and the exposed surface of the thermistor 2 are covered with a sealing member such as a resin because they are easily affected by vibration and the external environment. As a result, assembly can be performed in units of the lead frame 6, the mounting area can be reduced, and a structure resistant to vibration can be obtained.

FIG. 3 is a diagram showing a configuration of a physical package of an atomic oscillator according to the third embodiment of the present invention. The same components will be described with the same reference numerals as in FIG. This physical package 22 is
This is a configuration in which the Peltier element 5 is removed from the configuration of FIG. The semiconductor laser 1, the cell 3, and the PD 4 are directly provided on the lead frame 6. That is, the Peltier element 5 can control the temperature of the opposing surfaces by supplying current from the outside. However, the number of parts increases accordingly, which becomes an obstacle to downsizing. Therefore, in this embodiment, the temperature control is performed outside, except for the Peltier element 5. As a result, the atomic oscillator can be miniaturized and the cost can be reduced by reducing the number of parts.
In general, the resin that is a sealing member is black in order to block the influence of external light.
For this reason, if the resin 7 enters the gap between the connecting portions of the semiconductor laser 1, the cell 3, and the PD 4, there is a possibility that the light is hindered. Therefore, in the present embodiment, the resin 7 itself is constituted by a transparent member. Thereby, even if the resin enters the gap between the connecting portions, the component can be sealed without hindering light.
As another method, there is a method of filling the gap between the emission side of the semiconductor laser 1 and the incident side of the cell 3 and the gap between the emission side of the cell 3 and the incident side of the PD 4 with a transparent member. That is, in general, the resin that is a sealing member is black in order to block the influence of external light. for that reason,
If this resin enters the gap between the connecting portions of the semiconductor laser 1, the cell 3, and the PD 4, there is a possibility that the light will be blocked. Therefore, in this embodiment, a transparent member is filled in advance in the gaps of the respective connecting portions, and then the whole is sealed with the resin 7. Thereby, it is possible to prevent the resin 7 from entering the gap of the connection portion while blocking external light.

FIG. 4 is a view for explaining positioning grooves of parts formed on the Peltier element or the lead frame. 4A is a top view and FIG. 4B is a cross-sectional view taken along the line AA. That is, when the semiconductor laser 1, the cell 3, and the PD 4 are arranged side by side, the most important thing is to align the optical axes. Therefore, in this embodiment, the groove 9 is formed so that the optical axis is aligned when each component is set in the groove 9. This eliminates the need for optical axis alignment, and can reduce inspection man-hours and manufacturing costs.

FIG. 5 is a flowchart for explaining a process of manufacturing the atomic oscillator according to the embodiment of FIG. First, the Peltier element 5 is die-bonded to the lead frame 6 (S1). Next, the semiconductor laser 1, cell 3, and PD4 are die-bonded thereon (S2). Next, the terminal of each component and the lead terminal 8 for external connection provided in the lead frame 6 are wire-bonded (S3). Next, the connection surface of each component is fixed with a transparent adhesive (S4). Next, resin molding is performed with resin (S5).

FIG. 6 is a diagram showing a state in which the physical package 20 of the present invention is mounted on a substrate together with other IC chips. Since the physical package 20 of the present invention is similar in appearance to a universal IC package, the control circuit IC 23 is formed by a printed pattern 25 formed on the substrate 24.
By connecting to, the substrate 24 can be mass-produced by flowing to the production line in the same manner as the mounting using the conventional IC package.

FIG. 7 is a diagram showing a configuration of a physical package provided with a heat insulating material. FIG. 7A is a diagram in which a heat insulating material is provided on the surface of the resin, FIG. 7B is a diagram in which one layer of heat insulating material is provided inside the resin, and FIG. 7C is a diagram in which two layers are provided inside the resin. It is a figure provided with the heat insulating material. In FIG. 7A, a heat insulating material 10 is provided so as to cover the surface of the resin 7. FIG. 7B shows a configuration in which one layer of the heat insulating material 10 is formed in the process of forming the resin 7 and the resin is further covered thereon. FIG. 7C shows a structure in which two layers of the heat insulating material 10 are formed in the process of forming the resin 7 and the resin is further covered. That is, the semiconductor laser 1 or the cell 3 needs to be heated to a certain temperature. Therefore, it is important to prevent heat from escaping from the outside of the resin 7 in order to increase thermal efficiency. Therefore, in this embodiment, the heat insulating material 10 is disposed on the surface or inner layer of the resin 7. The effect of the heat insulating material 10 is enhanced by providing a plurality of layers. Thereby, the thermal efficiency of the heat source for heating the semiconductor laser 1 or the cell 3 can be increased. In addition, various modifications are made to the phenolic resin as a heat insulating material,
Phenol foam obtained by foam curing is excellent.

1 Semiconductor laser, 2 thermistor, 3 cell, 4 PD, 5 Peltier element, 6
Lead frame, 7 resin, 8 lead terminal, 9 groove, 10 heat insulating material, 20, 21, 22
Physical package, 23 Control circuit IC, 24 Substrate, 25 Print pattern

Claims (7)

A support member having a lead terminal for external connection;
Peltier element,
A light source for generating a resonant light pair that generates an electromagnetically induced transmission phenomenon in an alkali metal atom;
A cell encapsulating the alkali metal atom;
A light detecting means for detecting the resonant light pair transmitted through the alkali metal atom;
A temperature detection element for detecting the temperature of the Peltier element,
The Peltier element, the light source, the cell, and the light detection means are sequentially stacked on the support member to form a stacked body, and the exposed surface of the stacked body and the temperature detecting element is covered with a sealing member. An atomic oscillator. A support member having a lead terminal for external connection;
Peltier element,
A light source for generating a resonant light pair that generates an electromagnetically induced transmission phenomenon in an alkali metal atom;
A cell encapsulating the alkali metal atom;
A light detecting means for detecting the resonant light pair transmitted through the alkali metal atom;
A temperature detection element for detecting the temperature of the Peltier element,
The Peltier element and the temperature detection element are mounted on the support member, and the light source, the cell, and the light detection means are provided on the Peltier element, and the exposed surfaces of all components mounted on the support member are sealed by a sealing member. An atomic oscillator characterized by having a covering structure. The atomic oscillator according to claim 2, wherein the Peltier element is excluded, and the light source, the cell, and the light detection means are directly provided on the support member. The atomic oscillator according to claim 2 or 3, wherein a groove for forming the light source, the cell, and the light detection means is provided in the Peltier element or the support member. The atomic oscillator according to claim 1 or 2, wherein the sealing member is made of a transparent member. 6. The transparent member fills the gap between the light emission side of the light source and the incident side of the cell and the gap between the cell emission side and the incident side of the light detection means. An atomic oscillator according to claim 1. The atomic oscillator according to any one of claims 1 to 6, wherein a surface or an inner layer of the sealing member is covered with at least one heat insulating member.

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