JP2007036555A - Heating structure for oscillator, oscillator, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the consumed electric energy of a high accuracy reference oscillator such as an atomic oscillator and a constant temperature oven controlled crystal oscillator. <P>SOLUTION: Upper frames 71, lower frames 72, side face upper frames 73, and side face lower frames 74 each having thermal insulation performance fix a cell 41 inside a capsule 40 in an oscillation section 31 which an atomic oscillator includes, a heater driving body 47 is provided on each of heaters 43 for heating the cell 41, and the heater driving body 47 allows each heater 43 to be in contact with the cell 41 at heating of the cell 41 and separates each heater 43 from the cell 41 in the case of not heating the cell 41. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a heating structure in an oscillator, an oscillator having the heating structure, and an electronic apparatus including the oscillator.

Conventionally, some electronic timepieces divide a reference clock signal output from a reference oscillator to generate a signal of 1 Hz, for example, and time is measured based on the 1 Hz signal. As a reference oscillator, a crystal oscillator is often used. As a more accurate reference oscillator, an oven controlled crystal oscillator (OCXO) is known (for example, see Patent Document 1). In recent years, standard oscillators using atomic oscillators have been proposed (see, for example, Patent Documents 2 and 3).
JP 59-169209 A US Pat. No. 6,806,784 US Pat. No. 6,265,945

Since the above-described constant-temperature bath controlled crystal oscillator includes a heater for maintaining the temperature of the constant-temperature bath, power consumption is larger than that of a normal crystal oscillator. In an atomic oscillator, it is necessary to keep a cell in which atoms are encapsulated at a high temperature (for example, 80 ° C.), and power consumption required for heating the cell is large. Therefore, when these high-accuracy reference oscillators are used for battery-powered electronic timepieces, there is a problem that battery consumption is severe and long-term continuous driving is difficult.
Accordingly, an object of the present invention is to provide a heating structure, an oscillator, and an electronic device in an oscillator capable of suppressing power consumption of a high-precision reference oscillator such as an atomic oscillator or a thermostatic chamber controlled crystal oscillator.

In order to solve the above problems, the present invention is a heating structure in an oscillator having a configuration in which a heated object is heated by a heater, and the heated object is fixed in a case by a support having heat insulation, A heater displacing means configured to be able to come into contact with and to be separated from the heated body, to bring the heater into contact with the heated body when the heated body is heated, and to separate the heater from the heated body when not heated. It is characterized by providing.
According to the above configuration, the object to be heated is fixed in the case by the heat-insulating support, and the heater that heats the object to be heated is separated from the object to be heated when not heated. The loss of energy due to this can be suppressed to an extremely low level, and the power required for heating the heated object in the oscillator can be significantly reduced.

Further, the present invention provides an oscillator having a configuration in which a heated object is heated by a heater, the heated object is fixed in a case by a support having heat insulation, and the heater is in contact with the heated object. The heater is configured to be separable, and includes heater displacing means for bringing the heater into contact with the heated body when the heated body is heated and separating the heater from the heated body when not heated.
According to the above configuration, the object to be heated is fixed in the case by the heat-insulating support, and the heater that heats the object to be heated is separated from the object to be heated when not heated. The loss of energy due to the above can be suppressed to be extremely small, the power required for heating the heated object can be significantly reduced, and an oscillator with low power consumption can be provided.

  In this case, the oscillator may be an atomic oscillator including a cell in which medium atoms are enclosed as the heated object. The heated object may be a crystal oscillator. The heater displacing means may be configured using a piezoelectric element. Furthermore, the inside of the case may be configured to be a vacuum. Further, the tip of the support that is in contact with the heated body may be tapered.

Still further, the fixed heater that constantly heats the heated body while being in contact with the heated body, and the heated body is heated by the fixed heater and the heater at the start of use of the oscillator, It is good also as a structure provided with the heating control means which heats the said to-be-heated body only by the said fixed heater after use start.
Further, the apparatus includes temperature measuring means for measuring the temperature of the heated object, and the heating control means controls heating by the fixed heater and the heater based on the temperature measured by the temperature measuring means. Also good.

Further, the present invention provides an electronic device including an oscillator having a configuration in which a heated object is heated by a heater, wherein the oscillator fixes the heated object in a case by a support having heat insulation, A heater displacing means configured so that the heater can be brought into contact with and separated from the heated body, the heater is brought into contact with the heated body when the heated body is heated, and the heater is separated from the heated body when not heated. It is characterized by having.
According to the above configuration, the object to be heated included in the oscillator is fixed in the case by the heat insulating support, and the heater for heating the object to be heated is separated from the object to be heated when not heated. Energy loss due to heat radiation from the heater can be suppressed to a very small level, and the power required for heating the object to be heated in the oscillator can be remarkably reduced, so that the power consumption of the electronic device can be reduced.

  In the above configuration, the electronic device may be configured as a timepiece having a time display unit that displays time based on an oscillation signal generated by the oscillator.

  In addition, in the above, the support body having heat insulation refers to a structure configured to have a predetermined or higher thermal resistance between the object to be heated and not only a structure composed of a material having low thermal conductivity. , Including those with increased thermal resistance due to their shape (cross-sectional area, length).

  According to the present invention, it is possible to realize continuous driving for a long time even when a battery having a limited capacity is used as a power source by suppressing the power required for heating the object to be heated. In addition, when the oscillator is operated intermittently, heat dissipation during non-operation can be prevented, and the startup time for the next startup can be shortened.

Next, preferred embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a schematic configuration diagram of a timepiece according to a first embodiment to which the present invention is applied.
A timepiece 10 as an electronic apparatus of the present invention is configured as a wristwatch and includes a case 21. The case 21 is made of metal (titanium, stainless steel, aluminum, etc.) or resin. In particular, all or part of the periphery of the atomic oscillator 13 is made of a heat insulating material (not shown), and examples of the heat insulating material used include resins such as acrylic, polyethylene, and polystyrene. Also, DLC (Diamond Like Carbon: Carbon thin film with high hardness, electrical insulation, infrared transparency, etc. similar to diamond synthesized by gas phase synthesis using ions) around the atomic oscillator 13 of the case 21 Etc., or a ceramic or resin coating may be applied to form a heat insulating structure.
An inner frame 22 formed of a heat insulating material is accommodated in the central portion of the case 21. Examples of the material of the inner frame 22 include resins such as acrylic, polyethylene, and polystyrene, ceramics, soda glass, lead glass, and the like. In this inner frame 22, a battery 23 as a power source, a crystal oscillator 11 constituting the operation module 12, a watch IC 24, and a motor 17 are housed, and further, No. 5 driven by the power of the motor 17. A wheel train including a car 51, a fourth car 52, a third car 53, a second car 54, a minute wheel 55, and an hour wheel is stored. Further, the timepiece 10 includes a second hand, a minute hand, and an hour hand (all not shown) constituting a pointer portion 19 (FIG. 5) described later.
The rotor 17A of the motor 17 meshes with the fifth wheel 51, and the fourth wheel 52 meshes with the pinion 51A of the fifth wheel 51.
A second hand is attached to the rotation shaft of the fourth wheel 52 and the second hand is driven as the fourth wheel 52 rotates.

The third wheel 53 is engaged with the pinion 52A of the fourth wheel 52, and the second wheel 54 is engaged with the pinion 53A of the third wheel 53. A minute hand is attached to the rotation shaft of the second wheel 54, and the minute hand is driven as the second wheel 54 rotates. A minute wheel 55 is engaged with the pinion 54A of the second wheel 54. An hour wheel attached to the rotation shaft of the hour wheel is driven by rotation of the hour wheel which is not shown, and the hour wheel attached to the rotation shaft of the hour wheel.
Further, the minute wheel 55 is in mesh with the minute intermediate wheel 56. This day intermediate wheel 56 is connected to the crown 58 via a time correction wheel train 57.
The case 21 incorporates an atomic oscillator 13 that generates an oscillation signal with higher accuracy than the crystal oscillator 11. The operation module 12 and the atomic oscillator 13 are arranged in a three-dimensional space, and more specifically, an orthogonal projection of a predetermined plane (a plane parallel to the display surface) of the operation module 12 and the atomic oscillator 13. Are arranged so as not to overlap.
The atomic oscillator 13 is roughly divided into an oscillation unit 31 as an oscillator of the present invention, a local oscillator 32, and a control circuit unit 33. The control circuit unit 33 and the operation module 12 are flexible. It is electrically connected via the substrate 34.

The reason why the flexible substrate is used for exchanging signals between the atomic oscillator 13 and the operation module 12 is that the atomic oscillator 13 and the operation module 12 are thermally separated.
As will be described later, the oscillating unit 31 included in the atomic oscillator 13 keeps the cell 41 (FIG. 2) encapsulating cesium atoms at a high temperature during the operation. The heat of the cell 41 is transmitted from the atomic oscillator 13 to the operation module 12, so that the structural material constituting the operation module 12, deformation and alteration of materials such as gears, alteration of lubricant applied to the gears, and deterioration of the battery There is a possibility of causing problems such as circuit deformation and alteration.
Here, if the thermal conductivity of the material connecting the atomic oscillator 13 and the operation module 12 is λ, the cross-sectional area is A, and the distance between the two is x, the thermal resistance R between the two is expressed by the following equation.
R = x / (λ · A)
Accordingly, in order to thermally separate the atomic oscillator 13 and the operation module 12, it is only necessary to increase the thermal resistance R. Therefore, when connecting the two, the distance x is increased, the thermal conductivity λ is decreased, and the sectional area is reduced. It is preferable to reduce A.
However, the signal line provided for exchanging signals between the atomic oscillator 13 and the operation module 12 needs to perform minute signal transmission, that is, the distance x is set so as not to pick up unnecessary noise or the like. It can't be too big.
Therefore, in the present embodiment, the flexible substrate 34 having a small thermal conductivity λ and a small cross-sectional area A is used. Thereby, in the timepiece 10 in the present embodiment, the atomic oscillator 13 and the operation module 12 are thermally separated to reliably prevent the above-described problems.

  The oscillation unit 31 included in the atomic oscillator 13 includes a cell 41 as a heated object in which an alkali metal (cesium) is sealed in a glass tube, a laser diode 42 that emits laser light, and a plurality of heaters 43 that heat the cell 41. And a photodiode 44 that receives light emitted from the cell 41, emits laser light for excitation from the laser diode 42 to the cell 41 heated to a predetermined temperature by the heater 43, and passes through the cell 41. This is a cesium atomic oscillator that receives the laser beam by the photodiode 44.

2 and 3 are diagrams showing in detail the configuration of the oscillation unit included in the atomic oscillator. FIG. 2 is a partially broken perspective view, and FIG. 3 is a cross-sectional view taken along the line AA ′ of FIG.
As shown in FIG. 2, the oscillating unit 31 has a configuration in which the cell 41, the laser diode 42, the heater 43, and the photodiode 44 are accommodated in a capsule 40 as a substantially cylindrical case.
As shown in FIG. 3, the capsule 40 is a hollow container having a two-layered wall in which an outer layer 40A of a heat insulating material is arranged on the outer side and an inner layer 40B of a magnetic shielding material (metal or the like) is arranged on the inner side. The inside is a vacuum. Examples of the heat insulating material used for the outer layer 40A include resins such as acrylic, polyethylene, and polystyrene, ceramics, soda glass, lead glass, and the like.
In the capsule 40, a substantially cylindrical cell 41 is disposed so as to be positioned substantially at the center, a laser diode 42 is disposed on one side (lower side in the drawing) of the cell 41, and the other side (in the drawing side). A photodiode 44 is disposed on the upper side. That is, the cell 41, the laser diode 42, and the photodiode 44 are arranged side by side on the axis of the capsule 40, and laser light is emitted from the laser diode 42 along this axis.
In the following description, the upper side of the capsule 40 in FIG. 2, that is, the photodiode 44 side will be referred to as the upper side, and the lower side in FIG.

A laser temperature sensor 45 is disposed on the bottom surface of the capsule 40 at a position facing the laser diode 42. The laser temperature sensor 45 is a non-contact temperature sensor and measures the temperature of the laser diode 42. In addition, a cell temperature sensor 46 as a temperature measuring unit is disposed on the inner side surface of the capsule 40 so as to face the side surface of the cell 41. The cell temperature sensor 46 is a non-contact temperature sensor and measures the temperature of the cell 41.
The cell 41 is fixed in the capsule 40 by twelve frames serving as supports that are erected on the inner surface of the capsule 40. These 12 frames include three upper frames 71 erected downward from the top surface of the capsule 40, three lower frames 72 erected upward from the bottom surface of the capsule 40, It consists of three side upper frames 73 and three side lower frames 74 that are erected from the side surface toward the side surface of the cell 41.
The three side surface upper frames 73 are disposed at substantially equal intervals on the inner peripheral surface of the capsule 40 above the center of the cell 41 in the height direction. In addition, the three lower side frames 74 are disposed at substantially equal intervals on the inner peripheral surface of the capsule 40 below the center of the cell 41 in the height direction.
As shown in detail in FIG. 3, the side upper frame 73 and the side lower frame 74 can support the cells 41 more effectively if they are arranged so that the orthogonal projections on the cross section of the capsule 40 do not overlap. preferable. In the state shown in FIG. 3, the adjacent side upper frame 73 and the side upper frame 73, and the side lower frame 74 and the side lower frame 74 form an angle of about 120 degrees, respectively. The lower frame 74 forms an angle of about 60 degrees.

Each of the upper frame 71, the lower frame 72, the side surface upper frame 73, and the side surface lower frame 74 has a heat insulating property so that the heat of the cell 41 is not transmitted more than a predetermined amount.
As will be described later, the atomic oscillator 13 is intermittently driven every predetermined time (for example, 3 hours), and outputs a highly accurate oscillation signal for each drive. Since this high-accuracy oscillation signal is used to correct the oscillation signal generated by the crystal oscillator 11, there is no need to drive the atomic oscillator 13 at all times. An oscillation signal may be output from 31.
In order for the atomic oscillator 13 to output a highly accurate oscillation signal, the temperature of the cell 41 needs to be stable within a predetermined temperature range (for example, 80 ± 0.1 ° C.). Therefore, the atomic oscillator 13 heats the cell 41 with the heater 43 when starting its operation, and after the temperature of the cell 41 reaches the predetermined temperature range, the atomic oscillator 13 appropriately heats the cell 41. Is maintained within a predetermined temperature range. The holding time corresponds to the time for outputting the oscillation signal from the atomic oscillator 13, and is 10 seconds in the above example.

Since the temperature of the cell 41 is higher than that of other components located inside and outside the capsule 40, heat is radiated from the cell 41 to the surrounding components. Most of this heat radiation is via the above-described frames and the heater 43.
Therefore, in the present embodiment, each of the upper frame 71, the lower frame 72, the side surface upper frame 73, and the side surface lower frame 74 is made of a material having low thermal conductivity and has a tapered shape in each of these frames. Thus, a configuration having high heat insulation is provided, and heat radiation from the cell 41 through each frame is suppressed to the predetermined amount or less. The predetermined amount is an amount that can shorten the heating time by the heater 43. Specifically, after the cell 41 is heated and reaches the predetermined temperature range, the driving time of the oscillation unit 31 (the above example) In this case, it is desirable that the cell 41 does not become lower than the predetermined temperature range without being heated by the heater 43 during 10 seconds. In addition, it can be said that it is preferable that heating by the heater 43 is completed in a short time during the drive time of the oscillation unit 31 (10 seconds in the above example).

The material of the upper frame 71, the lower frame 72, the side surface upper frame 73, and the side surface lower frame 74 is preferably a material having a low thermal conductivity λ and a strength capable of securely fixing and supporting the cell 41, at least, Metal constituting the capsule 40 (for example, SUS304 (thermal conductivity λ = 16.3 [W / (m · K)]), SUS430 (thermal conductivity λ = 26.2 [W / (m · K)]) It is preferable that the thermal conductivity λ is significantly lower than that of stainless steel. More preferably, a material having a thermal conductivity λ of 0.5 or less, and still more preferably a material having a thermal conductivity λ of 0.25 or less. Specifically, for example, polystyrene (λ = 0.25 [W / (m · K)], tensile strength: 17 [N / mm ² ], the same applies hereinafter), polyethylene (λ = 0.08, Tensile strength: 53, compressive strength: 74 [N / mm ² (hereinafter the same)]), acrylic resin (λ = 0.17, tensile strength: 60, compressive strength: 125) are the most preferred examples. In addition, polycarbonate (λ = 0.19, tensile strength: 98, compressive strength: 102), polyester (λ = 0.15, tensile strength: 38, compressive strength: 218), PTFE Fluorine resin (λ = 0.25, tensile strength: 401, compressive strength: 394) such as PFA or PFA may be used, and other synthetic resins may be used.
Further, the upper frame 71, the lower frame 72, the side surface upper frame 73, and the side surface lower frame 74 are all formed such that the tip that contacts the cell 41 is tapered, and the cross-sectional area of the portion that contacts the surface of the cell 41 is extremely small. Yes.
As described above, since the thermal conductivity λ is small and the cross-sectional area A is small at the contact point between the cell 41 and each frame, the thermal resistance R obtained by the above formula becomes extremely large. That is, since each of these frames has a high heat insulating property, the heat escaping from the cell 41 through each of the frames is suppressed to a predetermined amount or less.

A plurality of heaters 43 for heating the cell 41 are disposed on the side surface of the cell 41. The heater 43 includes three upper heaters 43 </ b> A that are erected downward from the top surface of the capsule 40 and three lower heaters 43 </ b> B that are erected upward from the bottom surface of the capsule 40.
As shown in the perspective view of FIG. 4, the upper heater 43 </ b> A and the lower heater 43 </ b> B each have a wide tip portion. The wide end portion is constituted by a heating element that generates heat when energized, and the heating element is located along the side surface of the cell 41. The heating element at the tip of the heater 43 can be made of metal or ceramic. In addition, you may comprise the part except the front-end | tip part of the heater 43 with a heat insulating material.
Further, as shown in FIG. 4, a heater driving body 47 as a heater displacing means is disposed in each of the upper heater 43A and the lower heater 43B. The heater driving body 47 is composed of a piezo element, and is deformed by applying a voltage under the control of a control circuit 48 described later. The configuration and material of the heater driver 47 are arbitrary, and may be any material that can be deformed or displaced by being energized under the control of the control circuit 48. For example, a bimetal may be used.
The upper heater 43A and the lower heater 43B are configured to be displaceable with the deformation of the heater driving body 47. When the heater driving body 47 is not energized, the heater 43 is separated from the cell 41, and the heater driving body 47 is energized and deformed. Then, the heater 43 is in contact with the cell 41.

  Further, as will be described later, a control circuit 48 (FIG. 6) as a heating control means for controlling energization to the heater 43 and the heater driver 47 selects a part or all of the heater 43 when the cell 41 is heated. Then, the selected heater and the heater driver 47 arranged in the heater are energized. Accordingly, the six heaters 43 are in contact with the cell 41 only when heated, and are separated from the cell 41 when not heated, so that heat radiation from the cell 41 via the heater 43 is remarkably reduced.

Next, the timepiece control in this embodiment will be described.
FIG. 5 is a block diagram schematically showing the configuration of the timepiece control system.
In the following description, an oscillation signal generated by the crystal oscillator 11 included in the operation module 12 is a first oscillation signal SX1, and an oscillation signal generated by the atomic oscillator 13 is a second oscillation signal SX2. The second oscillation signal SX2 is an oscillation signal having higher frequency accuracy and frequency stability than the first oscillation signal SX1.
As described above, the motion module 12 includes the wheel train 18 including the fifth wheel 51, the fourth wheel 52, the third wheel 53, the second wheel 54, the minute wheel 55, and the hour wheel (all of which are shown in FIG. 1). And a crystal oscillator 11 and a motor 17, which are connected to a pointer portion 19 comprising an hour hand, a minute hand and a second hand. Further, the operation module 12 is based on the comparison result of the frequency / phase comparison circuit 14 that compares the frequency and phase of the first oscillation signal SX1 and the second oscillation signal SX2, and the first oscillation signal SX1 based on the comparison result of the frequency / phase comparison circuit 14. The frequency dividing circuit 15 generates and outputs the reference clock signal CLK, and the timepiece driving circuit 16 that drives the motor 17 based on the reference clock signal CLK. The frequency / phase comparison circuit 14, the frequency dividing circuit 15, and the timepiece driving circuit 16 are mounted on a timepiece IC 24 (FIG. 1).

The crystal oscillator 11 is configured to oscillate a tuning fork type crystal resonator, and outputs a first oscillation signal SX1 of, for example, 32.768 kHz.
The frequency dividing circuit 15 is configured by connecting a plurality of frequency dividers including a ½ frequency dividing circuit with a data set function that functions to give a logical slow / fast amount in multiple stages, and the first oscillation signal SX1 is The second oscillation signal SX2 is frequency-divided to 1 Hz using a correction reference, and a 1 Hz clock signal CLK is output.

FIG. 6 is an explanatory diagram showing a circuit configuration of the atomic oscillator.
The atomic oscillator 13 includes a cesium atomic oscillator as the oscillation unit 31, and generates and outputs an oscillation signal of, for example, 9.2 GHz.
The control circuit unit 33 controls the output of the laser diode 42 based on the temperature of the laser diode measured by the laser temperature sensor 45, and controls the heater 43 based on the temperature of the cell 41 measured by the cell temperature sensor 46. A control circuit 48 for processing the output signal of the photodiode 44, a local oscillator 49 for down-converting and outputting the frequency of the output signal of the photodiode 44 output through the control circuit 48 to a predetermined frequency, and a local oscillator 49 And a frequency dividing circuit 50 that divides the output signal and outputs it as the second oscillation signal SX2.

  Here, the control circuit unit 33 refers to the cell 43 with respect to the frequency corresponding to the energy difference between the energy level of the excited state accompanying the excitation of the cesium atom and the energy level of the ground state, and the heater 43. And the temperature of the cell 41 is maintained within a predetermined temperature range (for example, 80 ± 0.1 ° C.). More specifically, the laser diode 42 is modulated so that the frequency difference between the upper sideband and the lower sideband of the output matches the natural frequency of the cesium atom, and the amount of transmitted laser light in the cell 41 is higher. Since the frequency difference between the sideband and the lower sideband becomes the largest when it matches the natural frequency of the cesium atom, modulation is performed by adjusting the modulation frequency of the laser diode 42 so that the output of the photodiode 44 is maximized. The frequency is stabilized with reference to the natural frequency of the cesium atom. As a result, the second oscillation signal SX2 is also stabilized with reference to the natural frequency of the cesium atom.

  The control circuit 48 energizes the heater 43 and heats the cell 41 based on the temperature of the cell 41 detected by the cell temperature sensor 46 in order to keep the temperature of the cell 41 in the predetermined temperature range. In this case, the control circuit 48 can energize all the heaters 43 to heat the cells 41, or can energize only some of the heaters 43 to heat the cells 41. For example, when the temperature of the cell 41 is significantly lower than the predetermined temperature range as in the case where the atomic oscillator 13 starts operating from the stopped state, the control circuit 48 energizes all the heaters 43 to heat the cell 41. Further, for example, when the temperature of the cell 41 is close to the predetermined temperature range, only a part of the heaters 43 is energized to heat the cell 41. Further, when the heater 43 is energized to heat the cell 41, the control circuit 48 energizes the heater driving body 47 disposed in the heater 43 to bring the heater 43 into contact with the cell 41.

Next, the operation of the timepiece 10 will be described.
In the present embodiment, since a small portable watch such as a wristwatch is assumed, the atomic oscillator 13 is intermittently driven (in this embodiment, driven every 3 hours) from the viewpoint of reducing power consumption.

FIG. 7 is an operation flowchart centering on the oscillation operation.
After completion of the previous intermittent operation, a counter (not shown) is reset to start timing (step S1), and it is determined whether or not the drive stop period (3 hours) of the atomic oscillator 13 has elapsed based on the count value of the counter. (Step S2).
If it is determined in step S2 that it is still in the period for stopping the driving of the atomic oscillator 13 (step S2; n), the frequency dividing circuit 15 is connected to the 1/2 frequency dividing circuit with data set function (not shown). Based on the set correction data (or predetermined correction data in the case of the first time), the frequency of the first oscillation signal SX1 is divided while the logic of the first oscillation signal SX1 is performed, and a 1 Hz clock signal is generated. CLK is output to the timepiece driving circuit 16.
Thereby, the timepiece driving circuit 16 drives the motor 17.

As a result, the rotor 17A of the motor 17 rotates the fifth wheel 51 and drives the fourth wheel 52 via the pinion 51A of the fifth wheel 51. The second hand is driven as the fourth wheel 52 rotates.
Further, the third wheel 53 is driven through the pinion 52A of the fourth wheel 52, and the second wheel 54 is driven through the pinion 53A of the third wheel 53. The minute hand is driven as the second wheel & pinion 54 rotates.
Furthermore, the hour wheel 55 is driven by driving the hour wheel 55 that is meshed with the pinion 54A of the second wheel 54 and driving an hour wheel (not shown).
As a result, the current time is displayed.

  On the other hand, if the drive stop period of the atomic oscillator 13 has elapsed in step S2 (step S2; y), power is supplied to the atomic oscillator 13 to start oscillation of the oscillation unit 31 (step S3). In step S <b> 3, the oscillation unit 31 starts power supply from a stopped state and performs a so-called cold start. In this case, since the temperature of the cell 41 is significantly lower than the operating temperature during the stable operation (the predetermined temperature range), the control circuit unit 33 energizes all the heaters 43 and the heater driver 47 to heat the cells 41. Let Thereafter, when the temperature of the cell 41 approaches the predetermined temperature range, the control circuit unit 33 energizes only some of the heaters 43 and the heater driver 47 to heat the cell 41, and the temperature of the cell 41 is set to the predetermined temperature range. Keep within temperature range.

Subsequently, after a sufficient time has elapsed for the temperature of the cell 41 to stabilize within the predetermined temperature range and for the oscillation frequency of the atomic oscillator 13 to stabilize from the start of power supply to the atomic oscillator 13, the frequency / phase comparison circuit 14. Measures the frequency difference and phase difference between the first oscillation signal SX1 and the second oscillation signal SX2 (step S4), and outputs correction data to the frequency dividing circuit 15 based on the frequency difference and phase difference.
The data is output to the ½ divider circuit with a data set function of the divider circuit 15 to store correction data.

  Thereafter, when a drive period (for example, 10 seconds) sufficient for completing the above-described processing has elapsed since the start of power supply to the atomic oscillator 13, the power supply to the atomic oscillator 13 is shut off again, and the process is performed again. Is transferred to step S1 (step S7). Hereinafter, similarly, when the operation of the atomic oscillator 13 is stopped, the phase shift amount of the 1 Hz clock signal CLK is based on the correction data (the logical steep amount) stored in the ½ frequency divider with data set function. At the same time, every three hours, correction data (logical slow / fast) is calculated based on the frequency difference and phase difference between the second oscillation signal SX2 output from the atomic oscillator 13 and the first oscillation signal SX1 output from the crystal oscillator 11. Amount) is updated, and the process of correcting the phase shift amount of the clock signal CLK is repeated.

In parallel with this, the frequency dividing circuit 15 divides the frequency of the first oscillation signal SX1 based on the newly set correction data and divides the frequency of the first oscillation signal SX1 to generate a 1 Hz clock signal. CLK is output to the timepiece driving circuit 16.
Thereby, the timepiece driving circuit 16 drives the motor 17.
As a result, the rotor 17A of the motor 17 rotates the fifth wheel 51 and drives the fourth wheel 52 via the pinion 51A of the fifth wheel 51. The second hand is driven as the fourth wheel 52 rotates.
Further, the third wheel 53 is driven through the pinion 52A of the fourth wheel 52, and the second wheel 54 is driven through the pinion 53A of the third wheel 53. The minute hand is driven as the second wheel & pinion 54 rotates.

As described above, according to the present embodiment, in the oscillating unit 31 provided in the atomic oscillator 13, the cell 41 that is held at a higher temperature than the surrounding components is connected to the upper frame 71, the lower frame 72, and the side upper frame. 73 and a frame composed of a lower side frame 74, and the end of each frame is tapered, and heat insulation is achieved by using a material with low thermal conductivity for each frame. It is possible to significantly reduce heat dissipation through each frame.
In addition, by arranging the heater driver 47 in the plurality of heaters 43 that heat the cell 41 in the oscillating unit 31 and controlling the energization to the heater driver 47, the heater 43 contacts the cell 41 only during heating, Since it is configured to be separated from the cell 41 at the time of non-heating, it is possible to suppress heat radiation through the heater 43 to be extremely small. In particular, when the temperature of the cell 41 is close to a desired predetermined temperature range under the control of the control circuit 48, only some of the heaters 43 are brought into contact with the cell 41 to be heated, and the temperature of the cell 41 is significantly higher than the predetermined range. When the temperature is low, the cells 41 are heated by all the heaters 43, so that only the necessary minimum number of heaters 43 are in contact with the cells 41, and the heat radiation through the heaters 43 is kept very small.
In addition, since the inside of the capsule 40 is evacuated, heat that escapes from the surface of the cell 41 through the space inside the capsule 40 can be suppressed to a very small level.
As a result, it is possible to suppress energy loss due to heat dissipation from the cell 41, suppress the power required for maintaining the temperature of the cell 41, and efficiently maintain the temperature of the cell 41, and a battery having a limited capacity. 23 can be continuously driven for a long time. Then, it is possible to correct the first oscillation signal SX1 of the crystal oscillator 11 by the atomic oscillator 13, and to further improve the time display accuracy, and train station personnel such as subways and train operations that require accuracy. It can be sufficiently applied to a railway clock used by a person.

Further, since heat radiation from the cell 41 to the surrounding components is suppressed, various members such as the operation module 12 disposed around the atomic oscillator 13 are not affected by heat. For this reason, for example, it is possible to prevent deformation and alteration of materials such as structural materials and gears constituting the operation module 12, prevention of alteration of the lubricating oil applied to the gears, prevention of deterioration of the battery 23, and prevention of deformation and alteration of the circuit. Therefore, it is possible to prevent a decrease in time display accuracy due to these.
As described above, according to the present embodiment, it is possible to achieve high accuracy of time display accuracy while reliably avoiding a problem such as deterioration of components and shortening of the continuous drive time accompanying an increase in power consumption.

Further, when the power consumption of the oscillating unit 31 is 0.1 W, only 10 seconds are driven every 3 hours (10800 seconds), so the power consumed by the atomic oscillator 42 is 10/10800 times, that is, about 1 / 1000 times the power consumption (10 ⁻⁴ W), and even when the low-capacity battery 23 is used, it can be driven for a long time.

[Second Embodiment]
FIG. 8 is a partially broken perspective view showing the configuration of the oscillation unit in the second embodiment to which the present invention is applied.
The oscillating unit 31 shown in FIG. 8 is obtained by adding an upper heater 75 and a lower heater 76 as fixed heaters to the configuration of the oscillating unit 31 (FIG. 2) in the first embodiment. In FIG. 8, illustration of the upper frame 71, the lower frame 72, the side surface upper frame 73, and the side surface lower frame 74 is omitted. Further, parts other than the upper heater 75 and the lower heater 76 are denoted by the same reference numerals and description thereof is omitted.

  The upper heater 75 and the lower heater 76 are disk-shaped heaters that are in contact with the upper surface and the lower surface of the cell 41, respectively, a transparent conductive film such as ITO (Indium Tin Oxide), or a glass substrate or a plastic substrate on which the transparent conductive film is formed. The laser beam emitted from the laser diode 42 and the laser beam transmitted through the cell 41 are transmitted. The upper heater 75 and the lower heater 76 generate heat when energized by the control circuit 48 (FIG. 6) and function as heaters for heating the cell 41.

The control circuit 48 heats the cell 41 by energizing the upper heater 75 and the lower heater 76 in addition to the heater 43 in order to keep the temperature of the cell 41 in a predetermined temperature range. Specifically, when the temperature of the cell 41 is significantly lower than the predetermined temperature range, the control circuit 48 energizes all the heaters 43, the upper heater 75, and the lower heater 76 to heat the cell 41. When the temperature of the cell 41 is close to or within the predetermined range, only the upper heater 75 and the lower heater 76 are energized to heat the cell 41. That is, the upper heater 75 and the lower heater 76 are mainly used, and the heater 43 is used as an auxiliary heater at a cold start or the like.
Compared to the general heater 43, the thermal conductivity of the upper heater 75 and the lower heater 76 is small, and heat radiation through the upper heater 75 and the lower heater 76 is slight. For this reason, if all the heaters 43 are separated from the cell 41 and the cell 41 is heated only by the upper heater 75 and the lower heater 76, the heat radiation from the cell 41 can be kept small.
Therefore, in addition to the effect in the first embodiment, there is an advantage that the temperature of the cell 41 can be held more efficiently.
In the second embodiment, the control circuit 48 energizes the entire heater 43 or energizes only a part of the heater 43 depending on the temperature of the cell 41 measured by the cell temperature sensor 46. May be switched. By finely controlling the energization state of the heater 43 in this way, the cell 41 can be more efficiently held within the predetermined temperature range.

[Third Embodiment]
FIG. 9 is a cross-sectional view showing a schematic configuration of a timepiece according to the third embodiment to which the present invention is applied.
In each of the first and second embodiments, the movement including the battery 23, the operation module 12, and the pointer portion 19 and the atomic oscillator 13 are in a state in which the atomic oscillator 13 is disposed around the movement in a plan view. However, the third embodiment is a mode in which the atomic oscillator 13 is arranged so as to overlap the back side of the movement (reference numeral M in FIG. 9). In this case, the atomic oscillator 13 includes a back cover 60 and a cover 25 made of a material having magnetic resistance such as metal on the back side of the movement M (the side opposite to the pointer portion 19) inside the middle frame 22. It is stored in between and placed on the back cover 60. In this state, the periphery of the atomic oscillator 13 is surrounded by a heat insulating material 61.
The operation module 12 (see FIG. 1) in the movement M and the atomic oscillator 13 are electrically connected by a coil spring 62, and signal transmission is performed. In particular, when a coil spring is used, even if the product is developed by changing the output frequency of the second oscillation signal SX2, by changing any or all of the wire diameter, the number of turns, and the outer diameter of the coil By changing only the coil spring 62 without changing other components, it is possible to easily form an optimal signal transmission.
By using this coil spring 62, the distance x between the atomic oscillator 13 and the operation module 12 can be made larger, and the heat insulation can be improved.
Instead of the coil spring 62, a conductive rubber may be used.
The back cover 60 is made of metal or metal coated with ceramic, DLC or resin as a heat insulating coating. In this case, the cell 41 constituting the atomic oscillator 13 may be covered with a metal case.
Examples of the material of the heat insulating material 61 include resins such as acrylic, polyethylene, and polystyrene, ceramics, soda glass, lead glass, and the like.

  In the third embodiment, the atomic oscillator 13 is arranged on the back side of the movement M, but the atomic oscillator 13 may be arranged on the dial 65 side. In this case, it is more effective if the back surface of the dial plate 65 is coated with DLC, ceramic, or resin.

  Further, the present invention is not limited to the above-described first to third embodiments. For example, the atomic oscillator 13 may be housed in the watch band 67. In this case, it is preferable that the watch band 67 is made of a heat insulating material or the atomic oscillator 13 is covered with the heat insulating material. When the watch band 67 is made of a heat insulating material, it is made of a resin such as acrylic, polyethylene, or polystyrene, ceramic, or the like. Further, when the watch band 67 is made of metal, a coating such as DLC, ceramic, or resin may be applied. In this case, since the distance between the atomic oscillator 13 and the movement M including the operation module is long, the signal line becomes long and it becomes easy to pick up noise and the like. Therefore, an amplifier for signal amplification is provided in the atomic oscillator 13. Is desirable.

[Modification of Embodiment]
The above-described embodiments merely show one aspect of the present invention, and can be arbitrarily modified within the scope of the present invention.
[First Modification]
In the above description, the case where the frequency and phase of the first oscillation signal SX1 output from the crystal oscillator 11 and the second oscillation signal SX2 output from the atomic oscillator 13 are compared is illustrated, but the first oscillation signal SX1 and the second oscillation signal SX2 If the frequency of the oscillation signal SX2 matches, it is possible to compare only the phases.
Further, the frequency of the first oscillation signal SX1 and the second oscillation signal SX2 is compared, and the oscillation frequency of the first oscillation signal SX1 output from the crystal oscillator 11 with the frequency of the second oscillation signal SX2 output from the atomic oscillator 13 as a reference. May be corrected.

[Second Modification]
In the above description, the logic slow / fast method is adopted as the correction method of the clock signal CLK. However, the logical slow / fast method and the crystal oscillator capacity variable method may be used in combination. In this case, the adjustment range of the clock signal CLK can be expanded by using both the logical slow / rapid method and the variable capacity method. In addition, the capacitor for variable capacitance is not limited to the case where the capacitor for variable capacitance is provided in the capacitance variable type crystal oscillation circuit, and the capacitor for variable capacitance may be provided outside the crystal oscillation circuit.

[Third Modification]
In the above description, the case where the drive stop period of the atomic oscillator 13 is set to 3 hours and the drive period is set to 10 seconds is illustrated, but the present invention is not limited to this, and any time may be used.
In addition, the intermittent drive cycle is not evenly spaced, for example, the drive stop period is shortened in the daytime period (for example, 2 hours) and the nighttime period is lengthened (for example, 4 hours). It may be.
Further, in the above configuration, the crystal oscillator 11 may be eliminated, the atomic oscillator 13 may be driven at all times, and the operation module 12 may be driven based on an oscillation signal output from the atomic oscillator 13 instead of the crystal oscillator 11.

[Fourth Modification]
In the above description, the cesium atomic oscillator is used as the oscillating unit 31 of the atomic oscillator, but other atomic oscillators (for example, a rubidium atomic oscillator) may be used. Further, the crystal oscillator 11 may be an arbitrary crystal oscillator such as an oscillator used in an yearly clock or a monthly clock.
[Fifth Modification]
In the above description, the timepiece is provided with an atomic oscillator, but the present invention is not limited to this, and the present invention can be applied to a timepiece equipped with a thermostatic chamber controlled crystal oscillator. In this case, the thermostatic chamber provided in the thermostatic chamber control crystal oscillator is replaced with the cell 41, and the present invention is applied to the crystal oscillator enclosed in the thermostatic chamber and / or the thermostatic chamber (case) as the object to be heated. If this thermostat is configured to be heated by the heater 43 or the like shown in the embodiment and the modification, the loss of energy due to heat radiation from the thermostat is kept extremely small as in the above-described embodiments and modifications. It is possible to reduce the power required to maintain the temperature of the thermostatic chamber, to enable continuous driving for a long time using a battery with a limited capacity, and to further improve the time display accuracy. It becomes possible.

[Sixth Modification]
In the above description, it has been described that a coin-type primary battery such as a lithium battery or a silver battery is applied as the battery 23. However, the kinetic energy of a rotating weight that rotates by a solar panel or gravity is used as the rotor of the generator. A secondary battery may be used as the battery 23 by arranging a power generation means such as a power generation device that transmits kinetic energy to electrical energy.
Applies.
[Seventh Modification]
In the above description, the case of a wristwatch has been described, but the present invention is not limited to this, and may be applied to a table clock, or a digital timepiece or calendar that displays time using display means other than hands. Clocks with mechanisms, radio clocks that receive radio waves superimposed with time codes and correct the time based on the time codes, clocks such as pocket watches, table clocks and wall clocks, or mobile phones, PDA (Personal Digital Assistants) It can be widely applied to portable electronic devices such as portable measuring instruments and portable GPS (Global Positioning System) devices, or electronic devices that can be driven by other than commercial power sources such as standard oscillators and notebook personal computers. . Furthermore, the present invention can be widely applied to electronic devices that include an operation module (including or not including a clock module) that operates based on the reference clock signal and can be driven by a commercial power source. .

  In particular, when applied to radio clocks, it is not possible to receive radio waves, for example, where radio waves do not reach (in buildings, underground, underwater, near noise sources), or where there are no radio waves (no standard time signal) Location, space, etc.), antenna orientation is inappropriate, radio wave periodic inspection, radio frequency and time code are different, or there is a situation where the electric field strength decreases due to weather, etc. An accurate time can be displayed, and a highly accurate radio timepiece can be provided even under various circumstances. In addition, when applied to a data communication device such as a cellular phone, the clock signal from the oscillating unit 40 is used as a reference signal for determining a communication bit rate, so that highly reliable and high-speed communication can be performed. .

It is explanatory drawing which shows schematic structure of the timepiece in 1st Embodiment. It is a partially broken perspective view which shows the structure of the oscillation part with which an atomic oscillator is provided. It is sectional drawing in the AA 'line of FIG. It is a perspective view which shows the structure of a heater. It is a block diagram which shows the control system of the timepiece in 1st Embodiment. It is a block diagram which shows the structure of an atomic oscillator. It is a flowchart which shows operation | movement of the timepiece in 1st Embodiment. It is explanatory drawing of 2nd Embodiment. It is explanatory drawing of 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Timepiece (electronic device), 11 ... Crystal oscillator, 12 ... Operation module, 13 ... Atomic oscillator, 14 ... Frequency / phase comparison circuit, 15 ... Frequency divider circuit, 16 ... Clock drive circuit, 17 ... Motor, 18 ... Wheel Row 19, pointer portion 31, oscillation unit (oscillator), 40 capsule (case), 41 cell (heated object), 42 laser diode, 43 heater, 44 photodiode 46, cell temperature sensor (Temperature measuring means), 47 ... heater driving body (heater displacement means), 48 ... control circuit (heating control means), 49 ... local oscillator, 50 ... frequency dividing circuit, 71 ... upper frame (support), 72 ... lower Frame (support), 73 ... Side upper frame (support), 74 ... Side lower frame (support), 75 ... Upper heater (fixed heater), 76 ... Lower heater (fixed heater), SX1 ... First oscillation signal , X2 ... the second oscillation signal.

Claims (11)

A heating structure in an oscillator having a configuration for heating an object to be heated with a heater,
The heated object is fixed in the case by a support having heat insulation,
The heater is configured to be able to contact and separate from the heated body,
Providing a heater displacing means for bringing the heater into contact with the heated body when the heated body is heated and separating the heater from the heated body when not heated;
A heating structure in an oscillator characterized by the above. In an oscillator having a configuration for heating an object to be heated with a heater,
The heated object is fixed in the case by a support having heat insulation,
The heater is configured to be able to contact and separate from the heated body,
Providing a heater displacing means for bringing the heater into contact with the heated body when the heated body is heated and separating the heater from the heated body when not heated;
An oscillator characterized by.   3. The oscillator according to claim 2, wherein the oscillator is a cell including a cell in which medium atoms are sealed as the object to be heated.   The oscillator according to claim 2, wherein the object to be heated is a crystal oscillator sealed in a case.   The oscillator according to any one of claims 2 to 4, wherein the heater displacing means is configured using a piezoelectric element.   The oscillator according to claim 2, wherein the inside of the case is evacuated.   The oscillator according to any one of claims 2 to 6, wherein a tip of the support body in contact with the heated body is tapered. A stationary heater that constantly contacts the heated body and heats the heated body;
Heating control means for heating the object to be heated by the fixed heater and the heater at the start of use of the oscillator while heating the object to be heated only by the fixed heater after the start of use of the object to be heated;
The oscillator according to claim 2, further comprising: Comprising temperature measuring means for measuring the temperature of the object to be heated;
9. The oscillator according to claim 8, wherein the heating control unit controls heating by the fixed heater and the heater based on the temperature measured by the temperature measuring unit. In an electronic device including an oscillator having a configuration for heating a heated object with a heater,
The oscillator is
The heated body is fixed in a case by a support having heat insulation,
The heater is configured to be able to contact and separate from the heated object,
A heater displacing means for bringing the heater into contact with the heated body when the heated body is heated and separating the heater from the heated body when not heated;
Electronic equipment characterized by The electronic device according to claim 10, wherein the electronic device is configured as a timepiece having a time display unit that displays a time based on an oscillation signal generated by the oscillator.

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