CN219496901U - Physical system of CPT atomic clock - Google Patents

Abstract

The utility model relates to a physical system of CPT atomic clock, including mounting substrate and laser instrument subassembly, collimating lens subassembly and the magnetic shielding shell subassembly of arranging in order above that, the inside of magnetic shielding shell subassembly is provided with alkali metal plenum, the light passing hole has been seted up to the relative both sides of magnetic shielding shell subassembly, the coaxial setting of light passing hole on the optical axis of laser instrument subassembly, the optical axis of collimating lens subassembly and the magnetic shielding shell subassembly, the laser instrument subassembly includes first insulating support, a power field effect tube, VCSEL laser diode and a thermistor, the lower part and the mounting substrate fixed connection of first insulating support, a power field effect tube sets up on first insulating support, VCSEL laser diode and a thermistor are all fixed to on the fin of a power field effect tube. The S pole and the D pole of the first power field effect tube are respectively connected to the power supply and the ground, self-heating of the field effect tube is directly utilized to heat the laser diode, and the utilization efficiency of electric energy is high.

Description

Physical system of CPT atomic clock

Technical Field

The application relates to the field of atomic clocks, in particular to a physical system of a CPT atomic clock.

Background

The CPT atomic clock is a practical atomic clock which can be miniaturized and has low power consumption and great application potential. The CPT atomic clock is composed of a physical part and a circuit part. The physical part is an important energy consumption part of the main whole machine because of the need of heating and temperature control in the work. The power consumption of the whole CPT atomic clock is usually about 1W, and has certain advantages compared with the conventional rubidium atomic clock (typical power consumption is 8W-15W) and constant-temperature crystal oscillator (typical power consumption is 2W-5W), but the power consumption is not particularly obvious. The physical part of the novel CPT atomic clock adopts MEMS technology to reduce the size, adopts high vacuum heat insulation and other technology technologies to increase the heat resistance, reduces the power consumption to 0.1W-0.25W, has obvious advantages compared with the traditional atomic clock and constant temperature crystal oscillator, but has large MEMS technology and high vacuum heat insulation difficulty, complex manufacture and high product cost.

Disclosure of Invention

In view of this, the present application proposes a physical system of a CPT atomic clock, including a mounting substrate, and a laser assembly, a collimator lens assembly, and a magnetic shield assembly sequentially arranged on the mounting substrate; an alkali metal air chamber is arranged in the magnetic shielding shell assembly, and light passing holes are formed in two opposite sides of the magnetic shielding shell assembly; the optical axis of the laser component, the optical axis of the collimating lens component and the light passing hole on the magnetic shielding shell component are coaxially arranged; the laser assembly comprises a first heat insulation bracket, a first power field effect tube, a VCSEL laser diode and a first thermistor; the lower part of the first heat insulation bracket is fixedly connected with the mounting substrate; the first power field effect tube is arranged on the first heat insulation bracket; the VCSEL laser diode and the first thermistor are both fixed to the heat sink of the first power field effect transistor.

In one possible implementation, the VCSEL laser diode is adhesively secured to the heat sink of the first power fet by a conductive adhesive.

In one possible implementation, one end of the first thermistor is welded and fixed with the heat sink of the first power fet.

In one possible implementation manner, the first power field effect transistor is a P-type power field effect transistor, the S-stage of the first power field effect transistor is electrically connected with a power supply, and the D-stage of the first power field effect transistor is communicated with a heat sink on the first power field effect transistor so as to enable the D-stage of the first power field effect transistor to be grounded; the negative electrode of the VCSEL laser diode is electrically connected with the D electrode of the first power field effect transistor and grounded; one end of the first thermistor is electrically connected with the D pole of the first power field effect transistor and grounded; the D pole of the first power field effect tube, the negative pole of the VCSEL laser diode and one end of the first thermistor are equipotential points.

In one possible implementation, the magnetic shield assembly includes an outer shield box, a second thermally insulating support, and an inner shield box; the outer shielding box is fixedly arranged on the mounting substrate; the second heat insulation support is in a shape of a Chinese character pi and is fixed to the inner wall of the bottom of the outer shielding box; the inner shield case is located within the outer shield case, the inner shield case is secured to the second thermally insulating support, and the alkali metal plenum is disposed within the inner shield case.

In one possible implementation, the magnetic shield assembly further comprises a coil; the inner shielding box is in a convex shape, is horizontally arranged on the second heat insulation support, and is respectively provided with coils in symmetrical two side chambers, wherein the coils and the light passing holes are coaxially arranged; the alkali metal air chamber is made of columnar light-transmitting materials, and the coils on two sides are respectively attached to two light-transmitting surfaces of the alkali metal air chamber.

In one possible implementation manner, the second power field effect transistor and the second thermistor are fixedly arranged outside the opposite side walls of the inner shielding box, which are outwards protruded.

In one possible implementation, the outer shielding cage is spaced from the inner shielding cage by more than 1mm.

In one possible implementation, the light-entering side of the outer shielding box is provided with a quarter wave plate and a light-reducing plate; the light-emitting side of the outer shielding case is provided with a photodiode. The outer shielding box is a square box; the first thermistor and the second thermistor are NTC thermistors; the alkali metal air chamber is made of glass; and filling glue is filled in gaps between the coil, the alkali metal air chamber and the inner wall of the inner shielding box.

In one possible implementation, the collimating lens assembly includes a lens holder and a collimating lens body; the lens support is inverted U-shaped and fixedly arranged on the mounting substrate; the collimating lens main body is arranged on the inner side of the top of the lens support and matched with the arc-shaped structure of the lens support.

The beneficial effects of this application: through optimizing the structure on the laser subassembly, VCSEL laser diode and first thermistor bond or weld and directly fix on the fin of first power field effect transistor, save external power resistor, the S utmost point and the D utmost point of field effect transistor are connected to power and ground respectively, directly utilize self-heating of field effect transistor to carry out temperature control heating, and the utilization efficiency of electric energy is high. And integrally fixing the field effect transistor to the heat insulating support. The high thermal conductivity of metal connection is favorable to the temperature maintenance of each position of laser source subassembly unanimous, and the whole heat loss of constant temperature body is reduced as far as possible to the design of first insulating support and minification thereof to make the accuse temperature efficiency of laser source subassembly obtain improving, when satisfying this physical structure basic electrical property, effectual reduction complete machine consumption and volume improve the holistic price/performance ratio of CPT atomic clock of this application.

Other features and aspects of the present application will become apparent from the following detailed description of exemplary embodiments, which proceeds with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments, features and aspects of the present application and together with the description, serve to explain the principles of the present application.

FIG. 1 illustrates a side view of the physical system of a CPT atomic clock of an embodiment of the present application;

FIG. 2 illustrates a perspective view of a magnetic shield assembly of an embodiment of the present application;

fig. 3 shows a front view of a laser assembly according to an embodiment of the present application.

Fig. 4 shows a schematic diagram of a circuit portion of a laser assembly according to an embodiment of the present application.

Detailed Description

Various exemplary embodiments, features and aspects of the present application will be described in detail below with reference to the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements. Although various aspects of the embodiments are illustrated in the accompanying drawings, the drawings are not necessarily drawn to scale unless specifically indicated.

It should be understood, however, that the terms "center," "longitudinal," "transverse," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counter-clockwise," "axial," "radial," "circumferential," and the like indicate or are based on the orientation or positional relationship shown in the drawings, and are merely for convenience of description or to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be configured and operated in a particular orientation, and therefore should not be construed as limiting the present application.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present application, the meaning of "a plurality" is two or more, unless explicitly defined otherwise.

The word "exemplary" is used herein to mean "serving as an example, embodiment, or illustration. Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

In addition, numerous specific details are set forth in the following detailed description in order to provide a better understanding of the present application. It will be understood by those skilled in the art that the present application may be practiced without some of these specific details. In some instances, methods, means, elements, and circuits have not been described in detail as not to unnecessarily obscure the present application.

As shown in fig. 1-4, the physical system of the CPT atomic clock comprises: the laser device comprises a mounting substrate 40, a laser assembly 10, a collimating lens assembly 20 and a magnetic shielding shell assembly 30 which are sequentially arranged on the mounting substrate 40, wherein an alkali metal air chamber 34 is arranged in the magnetic shielding shell assembly 30, light passing holes are formed in two opposite sides of the magnetic shielding shell assembly, an optical axis of the laser assembly 10, an optical axis of the collimating lens assembly 20 and the light passing holes in the magnetic shielding shell assembly 30 are coaxially arranged, the laser assembly 10 comprises a first heat insulation support 14, a first power field effect tube 12, a VCSEL laser diode 11 and a first thermistor 13, the lower portion of the first heat insulation support 14 is fixedly connected with the mounting substrate 40, the first power field effect tube 12 is arranged on the first heat insulation support 14, and the VCSEL laser diode 11 and the first thermistor 13 are fixed on radiating fins of the first power field effect tube 12.

As shown in fig. 3 and 4, in this embodiment, by optimizing the structure on the laser assembly 10, the VCSEL laser diode 11 and the first thermistor 13 are directly fixed on the heat sink of the first power fet 12 by bonding or welding, so as to omit the external power resistor, the S pole and the D pole of the first power fet 12 are respectively connected to the power supply and the ground, the bottom of the heated VCSEL laser diode 11 and the heat sink D of the fet are extremely tightly fixed, self-heating of the fet is utilized, and the utilization efficiency of electric energy is high. And fix the whole field effect tube to the adiabatic support, the high thermal conductivity of metal connection is favorable to the temperature of each position department of laser source subassembly to keep unanimous, and the whole heat loss of constant temperature body is reduced as far as possible to the design of first adiabatic support 14 and its minification to make the accuse temperature efficiency of laser source subassembly obtain improving, when satisfying the basic electrical property of this physical structure, effectual reduction complete machine consumption and volume improves the holistic price/performance ratio of CPT atomic clock of this application.

The optical axis of the laser assembly 10, the optical axis of the collimator lens assembly 20, and the optical path 1 over the light passing hole in the magnetic shield assembly 30 in fig. 1 are schematic.

In one embodiment, the VCSEL laser diode 11 is adhesively secured to the heat sink of the first power fet 12 by conductive adhesive.

In this embodiment, preferably, the bottom of the heated VCSEL laser diode 11 and the D-pole of the first power fet 12 are tightly connected together by conductive silver paste, which makes the electric energy utilization efficiency of the two tightly attached to each other higher than the case where an external power resistor and fet connected in series are provided between the power supply and the ground to heat the heated object, and the energy consumed by the self-heating of the fet is not utilized.

In one embodiment, as shown in fig. 3, one end of the first thermistor 13 is welded to the heat sink of the first power fet 12.

As shown in fig. 3 and 4, in one embodiment, the first power fet 12 is a P-type power fet. The first power field effect tube 12 is a P-type power field effect tube, the S-stage of the first power field effect tube 12 is electrically connected with a power supply, and the D-stage of the first power field effect tube 12 is connected with a radiating fin on the first power field effect tube 12 so as to enable the D-stage of the first power field effect tube 12 to be grounded; the cathode of the VCSEL laser diode 11 is electrically connected with the D electrode of the first power field effect tube 12 and grounded; one end of the first thermistor 13 is electrically connected with the D pole of the first power field effect transistor 12 and grounded; the D pole of the first power fet 12, the negative pole of the VCSEL laser diode 11, and one end of the first thermistor 13 are equipotential points.

In this embodiment, the P-type power field effect transistor with metal heat sink is preferable, the metal heat sink is communicated with the D pole, and the D pole can be grounded in operation, because the negative pole of the VCSEL laser diode and one end of the thermistor can also be grounded, the three can be directly connected, so that the negative pole of the VCSEL laser diode 11, the D pole of the heat sink of the first power field heat sink 12, and one end of the first thermistor 13 are equal potential points connected with GND, and can be directly connected with each other, so that internal and external connection lines are simplified, the design of the laser assembly 10 is more reasonable, the structure is simpler, the installation of those skilled in the art is facilitated, more space can be saved, and the whole volume of the CPT atomic clock can be smaller.

In addition, for an N-type power field effect transistor, the D electrode must be connected to a power supply, the S electrode is grounded, the heat sink (D electrode) cannot be connected to the negative electrode of the VCSEL light emitting diode, and one end of the thermistor is required to be insulated. After the insulation is used, the whole structure is more complex, and the addition of the insulation material is unfavorable for heat conduction, so that the P-type power field effect transistor is better than the N-type power field effect transistor in selection.

In one embodiment, the magnetic shield assembly 30 further includes an outer shield case 31, a second heat insulating support 33 and an inner shield case 32, the outer shield case 31 is fixedly disposed on the mounting substrate 40, the second heat insulating support 33 is in a shape of a letter n, fixed to the bottom inner wall of the outer shield case 31, the inner shield case 32 is located within the outer shield case 31, the inner shield case 32 is fixed to the second heat insulating support 33, and the alkali metal air cell 34 is disposed within the inner shield case 32.

In this embodiment, the outer shielding case 31, the second heat insulation support 33 and the inner shielding case 32, and the opposite sides of the outer shielding case 31 and the inner shielding case 32 are provided with light holes with the same size, and one side is a light inlet hole, and the other side is a light outlet hole.

More specifically, the outer shielding box 31 is at normal temperature, no temperature control is needed, the inner shielding box 32 needs to be heated and controlled, a second heat insulation support 33 is installed in the middle of the box bottom of the outer shielding box 31, the second heat insulation support 33 is used for erecting and fixing the inner shielding box 32, and the alkali metal air chamber 34 is located in the inner shielding box 32.

As shown in fig. 2, in one embodiment, the magnetic shielding shell assembly 30 further includes a coil 35, the inner shielding box 32 is in a shape of a "convex", the coils 35 are respectively installed in symmetrical two side chambers of the inner shielding box 32 and are disposed coaxially with the light passing holes, the alkali metal air chamber 34 is made of square light-transmitting material, and the coils 35 located at two sides are respectively attached to two light passing surfaces of the alkali metal air chamber 34.

In this embodiment, the longitudinal projection of the inner shielding box 32 is in a shape of a "convex" shape, that is, the convex inner shielding box 32 is horizontally placed in the outer shielding box 31, the central line of the convex shape is a symmetry axis, the cavities at two sides of the convex shape are used to place the coils 35 at two sides of the alkali metal air chamber 34 respectively, the inner sides of the coils 35 are tightly attached to the light-passing surface of the air chamber, the outer sides of the coils 35 and the reserved gaps of the inner shielding chamber are filled with heat-conducting glue to ensure that the whole structure cannot shake in the inner shielding chamber, and special attention needs to be paid that the light-passing surface of the alkali metal air chamber 34 cannot be covered by the heat-conducting glue.

A small portion of gap allowance is reserved in the top cavity arranged to be convex, so that the light passing surface of the alkali metal air chamber 34 is adjusted to be consistent with the center of the light passing hole, and the structure can be used for effectively providing convenience for fine adjustment of operators in the field.

In one embodiment, the second power fet 36 and the second thermistor are fixedly mounted on opposite side walls of the inner shielding cage 32 protruding outwardly.

In this embodiment, the opposite sides of the top protrusion of the raised shape, i.e., the second power fet 36 and the second thermistor, are fixedly mounted on the side wall of the bottom of the raised shape, controlled by an external heating control circuit.

In one embodiment, as shown in fig. 2, the outer shield can 31 is spaced from the inner shield can 32 by a distance greater than 1mm.

In this embodiment, the distance between the outer shielding case 31 and the inner shielding case 32 is greater than 1mm, i.e., the height of the second heat insulation support 33 is greater than 1mm, so that the shortage of the distance between the bottom outer shielding case 31 and the inner shielding case 32 is avoided, and the material selected for the same has good heat insulation, can withstand high and low temperatures, and has a certain strength, preferably, for example, cork sheets, glass sheets, rigid polyurethane foam, etc. The second heat insulating support 33 is fixed to the inner and outer shield cases by adhesive. The structure can reduce heat conduction, has higher structural strength and is simple and convenient to install and manufacture.

In one embodiment, the light entrance side of the outer shield 31 is provided with a quarter wave plate 37 and a light reduction plate 38, and the light exit side of the outer shield 31 is provided with a photodiode 39.

In this embodiment, the quarter wave plate 37 is bonded to the outside of the light entrance hole of the outer shield case 31, the light reduction sheet 38 is bonded to the inside, and the photodiode 39 is bonded to the light exit hole of the outer shield case 31 to receive the light.

In one embodiment, the outer shielding case 31 is a square case, the first thermistor 13 and the second thermistor are NTC thermistors, the material of the alkali metal air chamber 34 is glass, and gaps between the coil 35, the alkali metal air chamber 34 and the inner wall of the inner shielding case 32 are filled with heat-conducting glue.

In one embodiment, the collimating lens assembly 20 includes a lens holder having an inverted "U" shape and fixedly disposed on the mounting substrate 40, and a collimating lens body mounted on the inner side of the top of the lens holder to match the arc-shaped structure of the lens holder.

In this embodiment, the collimator lens assembly 20 does not need to control the temperature, a mounting bracket of the collimator lens is made of a wire with proper thickness (such as a copper wire with the diameter of 0.5 mm), the wire is in a shape of a U, the inner diameter of a middle circular arc is the same as the outer diameter of the lens, the length of a straight leg is within 10mm, the circular arc is stuck on the collimator lens, a small amount of glue is applied at a contact position to bond the collimator lens integrally, pins are inserted into two straight-insertion pad holes reserved in the mounting substrate 40, the distance between the collimator lens and the mounting substrate 40 is not smaller than the distance between the VCSEL laser diode 11 and the mounting substrate 40, and then the bracket wire is welded to a pad of the mounting substrate 40 by soldering tin. The mounting bracket can effectively support a small and light collimating lens, and after a certain external force is applied, the metal wire can be subjected to plastic deformation, and the position and the gesture of the collimating lens are adjusted so as to finely adjust the light path 1, so that the optical axis of the collimating lens is finally overlapped with the connecting line between the centers of the VCSEL laser diode 11 and the photodiode 39, and the VCSEL laser diode 11 is positioned at the focal position of the collimating lens, so that the effect of receiving laser is optimal. After the light path 1 is adjusted, if the strength of the bracket is required to be further improved, a curable colloid can be smeared on the mounting bracket, and the strength is enhanced after the colloid is cured.

The embodiments of the present application have been described above, the foregoing description is exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the various embodiments described. The terminology used herein was chosen in order to best explain the principles of the embodiments, the practical application, or the improvement of technology in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.

Claims (10)

1. The physical system of the CPT atomic clock is characterized by comprising a mounting substrate, and a laser component, a collimating lens component and a magnetic shielding shell component which are sequentially arranged on the mounting substrate;

an alkali metal air chamber is arranged in the magnetic shielding shell assembly, and light passing holes are formed in two opposite sides of the magnetic shielding shell assembly;

the optical axis of the laser component, the optical axis of the collimating lens component and the light passing hole on the magnetic shielding shell component are coaxially arranged;

the laser assembly comprises a first heat insulation bracket, a first power field effect tube, a VCSEL laser diode and a first thermistor;

the lower part of the first heat insulation bracket is fixedly connected with the mounting substrate;

the first power field effect tube is arranged on the first heat insulation bracket;

the VCSEL laser diode and the first thermistor are both fixed to the heat sink of the first power field effect transistor.

2. The physical system of the CPT atomic clock of claim 1, wherein said VCSEL laser diode is adhesively secured to a heat sink of said first power fet by conductive glue.

3. The physical system of the CPT atomic clock according to claim 2, wherein one end of said first thermistor is welded to a heat sink of said first power fet.

4. The physical system of the CPT atomic clock according to claim 3, wherein said first power fet is a P-type power fet, the S-stage of said first power fet is electrically connected to a power supply, and the D-pole of said first power fet is connected to a heat sink on said first power fet to ground the D-pole of said first power fet;

the negative electrode of the VCSEL laser diode is electrically connected with the D electrode of the first power field effect transistor and grounded;

one end of the first thermistor is electrically connected with the D pole of the first power field effect transistor and grounded;

the D pole of the first power field effect tube, the negative pole of the VCSEL laser diode and one end of the first thermistor are equipotential points.

5. The physical system of the CPT atomic clock as claimed in any one of claims 1-4, wherein the magnetic shield assembly comprises an outer shield can, a second thermally insulating support and an inner shield can;

the outer shielding box is fixedly arranged on the mounting substrate;

the second heat insulation support is in a shape of a Chinese character pi and is fixed to the inner wall of the bottom of the outer shielding box;

the inner shield case is located within the outer shield case, the inner shield case is secured to the second thermally insulating support, and the alkali metal plenum is disposed within the inner shield case.

6. The physical system of the CPT atomic clock of claim 5, wherein said magnetic shield assembly further comprises a coil;

the inner shielding box is in a convex shape, is horizontally arranged on the second heat insulation support, and is respectively provided with coils in symmetrical two side chambers, wherein the coils and the light passing holes are coaxially arranged;

the alkali metal air chamber is made of columnar light-transmitting materials, and the coils on two sides are respectively attached to two light-transmitting surfaces of the alkali metal air chamber.

7. The physical system of the CPT atomic clock according to claim 6, wherein said inner shielding case has a second power fet and a second thermistor fixedly mounted on the outer side walls opposite to the outwardly convex side walls.

8. The physical system of the CPT atomic clock of claim 5, wherein the outer shielding cage is spaced from the inner shielding cage by a distance greater than 1mm.

9. The physical system of the CPT atomic clock according to claim 7, wherein the light-entering side of said outer shielding box is provided with a quarter-wave plate and a light-reducing plate;

a light emitting side of the outer shielding box is provided with a photodiode;

the outer shielding box is a square box;

the first thermistor and the second thermistor are NTC thermistors;

the alkali metal air chamber is made of glass;

and filling glue is filled in gaps between the coil, the alkali metal air chamber and the inner wall of the inner shielding box.

10. The physical system of the CPT atomic clock as claimed in any one of claims 1-4, wherein said collimating lens assembly comprises a lens holder and a collimating lens body;

the lens support is inverted U-shaped and fixedly arranged on the mounting substrate;

the collimating lens main body is arranged on the inner side of the top of the lens support and matched with the arc-shaped structure of the lens support.