Energy-saving chip atomic clock without vacuum thermal insulation structure

Abstract

The utility model relates to a kind of energy-saving chip atomic clock of vacuum heat insulation structure, including pedestal, top cover, main control circuit board, CPT physical part;Pedestal is rectangular plate structure, its upper surface is provided with pin;Main control circuit board shape is adapted with pedestal, and is welded on pin with bottom, and main control circuit board is equipped with flexible plate socket;CPT physical part is set on main control circuit board, can obtain high-precision alkali metal atom CPT resonance peak, applicable to the frequency of locking crystal oscillator;Circuit part is integrated on main control circuit board, including core time-keeping circuit and PLL circuit, core time-keeping circuit includes TCXO crystal oscillator, MCU, ADC, DAC;This energy-saving chip atomic clock of vacuum heat insulation structure has longer working life, production process is simpler, and comprehensive cost is lower.

Description

Technical Field

[0001] This utility model relates to the field of chip atomic clocks, and in particular to an energy-saving chip atomic clock without a vacuum insulation structure. Background Technology

[0002] As a miniature, high-precision time reference device, the chip atomic clock has become a core timing component in battery-powered scenarios such as deep-sea sensors and distributed IoT terminals, thanks to its miniaturized packaging, low power consumption, and excellent timekeeping performance.

[0003] Currently, the industry generally adopts high-vacuum thermal insulation solutions (such as MEMS vacuum cavity packaging) for thermal isolation. Although this can control power consumption within the range of 120mW-250mW, there are still technical bottlenecks: the vacuum level of the vacuum cavity is prone to decay over time (such as degradation of packaging sealing performance, micro-leakage in the cavity, etc.), which leads to a decrease in thermal isolation effect, which in turn causes atomic clock frequency drift and shortens the overall working life; moreover, the preparation of high-vacuum cavities requires complex processes such as ultra-fine processing and sealing vacuuming, which significantly increases the mass production cost of chip atomic clocks. Utility Model Content

[0004] In view of this, this application proposes an energy-saving chip atomic clock without vacuum insulation structure. While maintaining the main functions and performance indicators of chip atomic clocks, it avoids the existing high vacuum insulation process route and invents a chip atomic clock with longer working life, simpler production process and lower overall cost.

[0005] This utility model provides the following technical solution: an energy-saving chip atomic clock without vacuum insulation structure, characterized in that it includes: a base, a top cover, a main control circuit board, and a CPT physical part; The base is a rectangular plate structure with pins on its upper surface. The top cover is adapted to the shape of the base and serves to protect and block external interference. The main control circuit board is shaped to fit the base and is soldered to the pins. The main control circuit board is also provided with a flexible board socket. The CPT physical component is located on the main control circuit board, which can obtain high-precision alkali metal atom CPT resonance peaks, and is suitable for locking the frequency of the crystal oscillator; The main control circuit board includes a core timekeeping circuit and a PLL circuit. The core timekeeping circuit includes a TCXO crystal oscillator, an MCU, an ADC, and a DAC. The CPT physical part is electrically connected to the MCU and the PLL circuit, and is powered on in CPT calibration mode and powered off in crystal oscillator timekeeping mode, with the two modes working alternately.

[0006] In one embodiment of the utility model, the CPT physical part includes: a VCSEL laser assembly, a magnetic shielding assembly, a flexible plate, and internal functional components; The VCSEL laser assembly includes a VCSEL laser and a laser circuit board. The laser circuit board is vertically mounted on the main control circuit board and fixed by soldering to the bottom pads. The VCSEL laser is mounted on the laser circuit board, and the optical axis of the VCSEL laser is parallel to the base plane. The magnetic shielding assembly includes a magnetic shielding cavity and a magnetic shielding cover. The magnetic shielding cavity is a square body with an open top and is embedded in the main control circuit board. The magnetic shielding cover is fitted onto the top of the magnetic shielding cavity. The magnetic shielding cover has a notch on its edge. The depth of the notch is the same as the thickness of the magnetic shielding cover, and the width matches the flexible plate. The internal functional components are housed within the magnetic shielding cavity. The flexible plate is electrically connected to the internal functional components. After being flipped horizontally and vertically twice, the flexible plate is led out from the notch in the magnetic shielding cover and inserted into the flexible socket.

[0007] In one embodiment of the utility model, the internal functional components include a C-field coil, a heat insulation pad, a heat transfer cavity, a quarter-wave plate, an alkali metal gas chamber, a silicon PIN photodiode, and a heating and temperature control element. The C-field coil is a hollow self-adhesive coil with dimensions smaller than the magnetic shielding cavity. It is wrapped with PTFE tape and can be embedded in the magnetic shielding cavity. The heat insulation pad is adhered to the inner wall of the C-field coil, and the heat transfer cavity is adhered to the heat insulation pad and located at the bottom of the magnetic shielding cavity. The heat transfer cavity is a rectangular cuboid structure with an inlet hole on the side facing the VCSEL laser. The heat transfer cavity has an opening on the side perpendicular to the optical axis of the VCSEL laser. The quarter-wave plate is fixed outside the inlet hole. The alkali metal gas chamber is a cubic glass bubble structure placed inside the heat transfer cavity. A gas nozzle is provided on the side. The gas nozzle is cylindrical and injects a trace amount of alkali metal and buffer gas into the alkali metal gas chamber. The gas nozzle is sealed after production. The silicon PIN photodiode and the heating and temperature control element are fixed on the side of the heat transfer cavity away from the VCSEL laser.

[0008] In one embodiment of the utility model, a TO tube shell is also included; The VCSEL laser is packaged in the TO housing, which also integrates a miniature TEC and an NTC thermistor. The VCSEL laser is thermally coupled to the miniature TEC and the NTC thermistor. The main control circuit is electrically connected to the NTC thermistor and the miniature TEC to control the temperature of the VCSEL laser between 60°C and 100°C.

[0009] In one embodiment of the invention, the laser circuit board has 6 to 12 double-row pads on its edge, which are used for power supply, grounding, laser driving, temperature setting, and temperature monitoring signal transmission, respectively. In another embodiment, both the magnetic shielding cavity and the magnetic shielding cover are made of permalloy sheet metal through stretching.

[0010] In one embodiment of the utility model, the C-field coil is a multi-layer self-adhesive hollow coil, the external dimensions of the C-field coil are adapted to the inner cavity formed by the magnetic shielding cavity and the magnetic shielding cover, and the number of turns of the PTFE tape is 2 to 4.

[0011] In one embodiment of the utility model, the waist of the magnetic shielding cavity is welded and fixed to the main control circuit board through the double row of solder pads, and the magnetic shielding cover is fixed to the magnetic shielding cavity through silicone rubber.

[0012] In one embodiment of the utility model, the MCU can receive an external 1PPS reference signal; When the external 1PPS reference signal is valid, the MCU controls the CPT physical part to be continuously powered on to maintain the CPT calibration mode, and achieves discipline by fine-tuning the CPT physical part, while synchronizing the internally output 1PPS signal; when the external 1PPS reference signal is invalid, the MCU automatically switches to alternate between CPT calibration mode and crystal oscillator timekeeping mode.

[0013] In one embodiment of the utility model, before the atomic clock switches from CPT calibration mode to crystal oscillator timekeeping mode, the operating parameters of the CPT physical part in CPT calibration mode are recorded, and the operating parameters are used as the initial parameters when the CPT calibration mode is started next time.

[0014] The beneficial effects of this invention are as follows: By integrating the CPT physical part, the core timing circuit including the TCXO crystal oscillator, and the PLL circuit onto the main control circuit board, and using the high-precision alkali metal atom CPT resonance peak to lock the crystal oscillator frequency, the timing accuracy is guaranteed. This significantly improves the integration level to reduce the size of the device, adapting to miniaturization requirements. It also eliminates the need for a vacuum insulation structure, simplifying the design, reducing manufacturing complexity and cost, and avoiding potential stability issues associated with vacuum structures. More importantly, the MCU can control the CPT physical part to be powered on in CPT calibration mode and powered off in crystal oscillator timing mode, enabling alternating operation of the two modes. This significantly reduces power consumption during non-calibration phases, ultimately achieving a balance between high-precision timing and low power consumption. This invention is suitable for scenarios with comprehensive requirements for device size, power consumption, and time accuracy.

[0015] Other features and aspects of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0016] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this application together with the specification and serve to explain the principles of this application.

[0017] Figure 1 This diagram illustrates the main structure of an energy-saving chip atomic clock with a vacuum-insulated structure according to an embodiment of this application. Figure 2 A cross-sectional view of the CPT physical portion of an embodiment of this application is shown. Detailed Implementation

[0018] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0019] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model or simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0021] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0022] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0023] Specific references Figure 1 As an energy-saving chip atomic clock without vacuum insulation structure according to this utility model, the device includes: a base 1, a top cover, a main control circuit board 2, and a CPT physical part; the base 1 is a rectangular plate structure with pins 21 on its upper surface, and the top cover is adapted to the shape of the base 1, serving to protect and block external interference; the main control circuit board 2 is adapted to the shape of the base 1 and is soldered to the pins 21, and the main control circuit board 2 is provided with a flexible board socket 31; the CPT physical part is set on the main control circuit board 2, which can obtain high-precision alkali metal atom CPT resonance peaks, suitable for locking the frequency of the crystal oscillator; the main control circuit board 2 includes a core timekeeping circuit and a PLL circuit 4, the core timekeeping circuit includes a TCXO crystal oscillator 51, an MCU 52, an ADC 53, and a DAC 54; the CPT physical part is electrically connected to the MCU 52 and the PLL circuit 4, and is powered on in CPT calibration mode and powered off in crystal oscillator timekeeping mode, with the two modes working alternately.

[0024] In this example, the main body of the chip atomic clock is 40mm long, 35mm wide, and 11.5mm high, with 9 pins 21 at the bottom, each with a nominal diameter of 0.8mm.

[0025] In this example, the internal crystal oscillator is a 10MHz wide-temperature VC-TCXO, powered by a voltage regulator circuit with a voltage of about 3V and a current of about 2mA.

[0026] In one specific embodiment, the CPT physical component includes: a VCSEL laser assembly, a magnetic shielding assembly, a flexible plate 32, and internal functional components.

[0027] In one specific embodiment, the VCSEL laser assembly includes a VCSEL laser 42 and a laser circuit board 41. The laser circuit board 41 is vertically mounted on the main control circuit board 2 and fixed by soldering to the bottom pad. The VCSEL laser 42 is mounted on the laser circuit board 41, and the optical axis of the VCSEL laser 42 is parallel to the plane of the base 1.

[0028] In this example, the VCSEL laser 42 is packaged in a TO46 housing 43 with a glass window. The housing 43 integrates a miniature TEC (thermal cooler) and an NTC thermistor. The three are thermally coupled to achieve temperature linkage. The MCU connects the NTC thermistor and the miniature TEC through electrical connection to form a closed-loop temperature control, which stabilizes the operating temperature of the VCSEL laser 42 between 60°C and 100°C, and avoids temperature drift that causes laser wavelength shift.

[0029] In this example, the laser circuit board 41 is a small rectangular board, the size of which is adapted to the space of the VCSEL package and the main control circuit board 2. It stands vertically on the main control circuit board 2 and is fixed by soldering to the bottom pads. The pads must ensure mechanical support in the vertical direction. Its edge has 6 to 12 double-row pads, which are used for power supply, grounding, drive current control signals and TEC temperature control signals of VCSEL laser 42, respectively, to ensure that each signal is transmitted independently without interference.

[0030] In this example, the optical axis of the VCSEL laser 42 is parallel to the plane of the base 1 and aligned with the center of the alkali metal gas chamber 411 in the subsequent internal functional components. The optical path distance is controlled between 10 mm and 20 mm, and the distance from the bottom of the base is between 5 mm and 8 mm, ensuring that the laser can be incident perpendicularly into the alkali metal gas chamber 411.

[0031] In one specific embodiment, the magnetic shielding assembly includes a magnetic shielding cavity 411 and a magnetic shielding cover 412. The magnetic shielding cavity 411 is a square body with an open top and is embedded in the main control circuit board 2. The magnetic shielding cover 412 covers the top of the magnetic shielding cavity 411. The edge of the magnetic shielding cover 412 is provided with a notch. The depth of the notch is the same as the thickness of the magnetic shielding cover 412, and the width matches the flexible plate 32.

[0032] In this example, both are made of permalloy sheet with high magnetic permeability through stretching, with a wall thickness of 0.2mm to 0.5mm. The inner dimensions of the magnetic shielding cavity 411 are 10mm~15mm (length) × 10mm~15mm (width) × 7mm~10mm (height). The bottom of the cavity 411 is close to the base 1 to reduce the heat conduction path. The waist is fixed to the edge of the square slot of the main control circuit board 2 by four solder pads to ensure that the cavity does not wobble. A light inlet hole with a diameter of 1mm~5mm is opened on the side of the cavity facing the VCSEL laser 42 for laser incident.

[0033] In this example, the magnetic shielding cover 412 and the magnetic shielding cavity 411 are fixed together by bonding with silicone rubber, which must be heat resistant.

[0034] In one specific embodiment, the internal functional components include a C-field coil 43, a heat insulation pad 431, a heat transfer cavity 44, a quarter-wave plate 45, an alkali metal gas chamber 441, a silicon PIN photodiode 47, and a heating and temperature control element 46.

[0035] In this example, the C-field coil 43 is a multilayer self-adhesive hollow square tube coil, wound with enameled wire of diameter 0.05mm~0.3mm, with a total number of 100~500 turns. The external dimensions of the coil 43 are adapted to the inner cavity formed by the magnetic shielding cavity 411 and the magnetic shielding cover 412, ensuring that the coil can be tightly embedded. The outer periphery is wrapped with 2~4 turns of PTFE tape, which has both insulation and buffering functions, preventing the coil 43 from short-circuiting and avoiding collision between the coil 43 and the cavity. The coil 43 covers the inside of the magnetic shielding cavity 411 for one circumference. After being energized, it generates a uniform axial magnetic field, which is used to eliminate the energy level degeneracy of alkali metal atoms and improve the resolution of the CPT resonance peak.

[0036] In this example, the heat insulation pad 431 is made of balsa wood with low thermal conductivity and has a size of 5mm~10mm (length) × 5mm~10mm (width) × 2mm~3mm (thickness). It is bonded to the inner wall of the C-field coil 43 with high-temperature resistant adhesive. Its function is to isolate the heat transfer between the C-field coil 43 and the heat transfer cavity 44 and reduce heat loss.

[0037] In this example, the heat transfer cavity 44 is made of copper through stretching, which has a high thermal conductivity. It is a rectangular cuboid structure with dimensions of 5mm (length) × 4mm (width) × 4mm (height). The opening is perpendicular to the optical axis 42 of the VCSEL laser and is used to house the alkali metal gas chamber 441. The heat transfer cavity 44 is bonded to the heat insulation pad 431 with high-temperature resistant adhesive, and has a 2mm diameter light inlet hole on the side facing the VCSEL laser 42. The function of the heat transfer cavity is to uniformly transfer the heat from the heating and temperature control element 46 to the alkali metal gas chamber 441, ensuring the stable vaporization of alkali metal atoms in the gas chamber 441.

[0038] In this example, the quarter-wave plate 45 is selected to match the wavelength of the VCSEL laser, with an external size of 2mm to 4mm. It is fixed to the outside of the light inlet of the heat transfer cavity 44 by dispensing adhesive. It is used to convert the linearly polarized laser output by the VCSEL laser 42 into a circularly polarized laser to meet the polarization requirements of the CPT transition of alkali metal atoms.

[0039] In this example, the alkali metal gas chamber has an external dimension of approximately 3.5 mm and an internal dimension of approximately 2 mm. It contains trace amounts of rubidium or cesium and an inert buffer gas. A cylindrical nozzle 442 is provided on one side of the gas chamber 441 for injecting alkali metal and buffer gas during preparation. The nozzle 442 is sealed after preparation is completed. The alkali metal gas chamber 441 is inserted from the opening of the heat transfer cavity, close to the side of the light inlet hole, to ensure that the laser can pass through the gas chamber 441.

[0040] In this example, the silicon PIN photodiode 47 is fixed on the side of the heat transfer cavity 44 away from the VCSEL laser 42 and close to the alkali metal gas chamber 441. It is used to receive the laser intensity signal passing through the gas chamber 441. The laser intensity changes with the CPT resonance peak and is a frequency-locked feedback signal. The heating and temperature control element 46 includes a power transistor and an NTC thermistor. Both are fixed on the same side of the heat transfer cavity 44 and adjacent to the silicon PIN photodiode 47. They form a temperature closed loop through the MCU 52 to stabilize the temperature of the alkali metal gas chamber 441 at about 75°C and ensure the stability of the alkali metal atom concentration in the gas chamber.

[0041] In one specific embodiment, the flexible board 32 is a thin flexible circuit board with a thickness of about 0.1mm to 0.2mm. One end is electrically connected to the electrical components of the internal functional components, and the other end is flipped twice, first horizontally and then vertically, and then led out from the notch of the magnetic shielding cover 412 and finally inserted into the flexible board socket 31 of the main control circuit board 2. The double flipping design of the flexible board can avoid interference with other components in the cavity, while ensuring the reliability of the connection after being led out.

[0042] In one specific embodiment, the atomic clock implements an alternating operating logic of CPT calibration mode and crystal oscillator timekeeping mode. In CPT calibration mode, the operating time is short, with all components powered on; in crystal oscillator timekeeping mode, the operating time is long, with only a small portion of the control circuit powered on, thus significantly reducing average power consumption and achieving both accuracy and energy saving.

[0043] In this example, after the atomic clock is powered on, all circuits are powered on, and the MCU52 executes the initialization process: It starts the heating and temperature control element 46 to heat the alkali metal chamber 441 to about 75°C and the VCSEL laser 42 to 70~90°C; it starts the VCSEL laser 42 drive circuit to quickly scan the laser's drive current, and simultaneously collects the light intensity signal of the silicon PIN photodiode 47 through the ADC53. When the microwave-modulated alkali metal atom absorption spectrum is detected, the temperature scan stops; it fine-tunes the DC current of the VCSEL laser 42 to lock the laser wavelength to the maximum absorption peak of the alkali metal atom; it starts the PLL circuit 4 to scan the microwave frequency, and when the ADC53 detects the peak value of the laser intensity, it adjusts the output frequency of the PLL circuit 4 through the DAC54 to lock the microwave frequency to the CPT transmission peak. At this time, the atomic clock completes CPT locking.

[0044] In this example, when there is a 1PPS input: the MCU52 controls the CPT physical section to be continuously powered on to maintain the CPT calibration mode; at the same time, by comparing the time difference between the internal 1PPS and the external 1PPS, the parameters of the CPT physical section are finely adjusted to tame the atomic clock; usually after more than 15 minutes of taming, the output frequency accuracy of the atomic clock can be improved to the E-11 level, and the internal 1PPS and the external 1PPS are synchronized.

[0045] In this example, when there is no 1PPS input: the MCU52 automatically switches between CPT calibration mode and crystal oscillator timekeeping mode, alternating between the two. CPT calibration mode operates continuously for 2 minutes, during which the CPT physical section, PLL circuit 4, and core timekeeping circuit are all powered on. The MCU52 calibrates the TCXO frequency using the CPT resonant peak and updates the DAC54 voltage-controlled parameters. Crystal oscillator timekeeping mode refers to the MCU52 recording the current operating parameters of the CPT physical section and the TCXO's DAC voltage-controlled value after CPT calibration, then turning off the power to the CPT physical section and PLL circuit 4, leaving only the core timekeeping circuit powered on. This mode operates continuously for 30 minutes, during which the TCXO outputs a stable clock signal based on the latest DAC parameters. After crystal oscillator timekeeping mode ends, the MCU52 uses the previously recorded CPT parameters as initial values, quickly starts the CPT physical section, and enters the next round of CPT calibration mode without rescanning.

[0046] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. An energy-saving chip atomic clock without vacuum insulation structure, characterized in that, include: Base, top cover, main control circuit board, CPT physical components; The base is a rectangular plate structure with pins on its upper surface. The top cover is adapted to the shape of the base and serves to protect and block external interference. The main control circuit board is adapted to the base and is soldered to the pins. The main control circuit board is also provided with a flexible board socket. The CPT physical component is located on the main control circuit board, which can obtain high-precision alkali metal atom CPT resonance peaks, and is suitable for locking the frequency of the crystal oscillator. The main control circuit board includes a core timekeeping circuit and a PLL circuit. The core timekeeping circuit includes a TCXO crystal oscillator, an MCU, an ADC, and a DAC. The CPT physical part is electrically connected to the MCU and the PLL circuit, and is powered on in CPT calibration mode and powered off in crystal oscillator timekeeping mode, with the two modes working alternately.

2. The energy-saving chip atomic clock with a vacuum-insulated structure according to claim 1, characterized in that, The physical components of the CPT include: a VCSEL laser assembly, a magnetic shielding assembly, a flexible plate, and internal functional components; The VCSEL laser assembly includes a VCSEL laser and a laser circuit board. The laser circuit board is vertically mounted on the main control circuit board and fixed by soldering to the bottom pad. The VCSEL laser is mounted on the laser circuit board, and the optical axis of the VCSEL laser is parallel to the base plane. The magnetic shielding assembly includes a magnetic shielding cavity and a magnetic shielding cover. The magnetic shielding cavity is a square body with an open top and is embedded in the main control circuit board. The magnetic shielding cover is fitted onto the top of the magnetic shielding cavity. The magnetic shielding cover has a notch on its edge. The depth of the notch is the same as the thickness of the magnetic shielding cover, and the width matches the flexible plate. The internal functional components are disposed within the magnetic shielding cavity. The flexible plate is electrically connected to the internal functional components. After being flipped horizontally and vertically twice, the flexible plate is led out from the notch of the magnetic shielding cover and inserted into the flexible plate socket.

3. The energy-saving chip atomic clock with a vacuum-insulated structure according to claim 2, characterized in that, The internal functional components include a C-field coil, a heat insulation pad, a heat transfer cavity, a quarter-wave plate, an alkali metal gas chamber, a silicon PIN photodiode, and a heating and temperature control element. The C-field coil is a hollow self-adhesive coil with dimensions smaller than the magnetic shielding cavity. It is wrapped with PTFE tape and can be embedded in the magnetic shielding cavity. The heat insulation pad is adhered to the inner wall of the C-field coil, and the heat transfer cavity is adhered to the heat insulation pad and located at the bottom of the magnetic shielding cavity. The heat transfer cavity is a rectangular cuboid structure with an inlet hole on the side facing the VCSEL laser. The heat transfer cavity has an opening on the side perpendicular to the optical axis of the VCSEL laser. The quarter-wave plate is fixed outside the inlet hole. The alkali metal gas chamber is a cubic glass bubble structure placed inside the heat transfer cavity. It has a gas nozzle on the side. The gas nozzle is cylindrical and injects a trace amount of alkali metal and buffer gas into the alkali metal gas chamber. The gas nozzle is sealed after production. The silicon PIN photodiode and the heating and temperature control element are fixed inside the heat transfer cavity on the side away from the VCSEL laser.

4. The energy-saving chip atomic clock with a vacuum-insulated structure according to claim 2, characterized in that, Also includes TO casing; The VCSEL laser is packaged in the TO tube housing, which also integrates a miniature TEC and an NTC thermistor. The VCSEL laser is thermally coupled to the miniature TEC and the NTC thermistor. The main control circuit is electrically connected to the NTC thermistor and the miniature TEC to control the temperature of the VCSEL laser between 60°C and 100°C.

5. The energy-saving chip atomic clock with a vacuum-insulated structure according to claim 2, characterized in that, The laser circuit board has 6 to 12 double-row pads on its edge, which are used for power supply, grounding, laser driving, temperature setting, and temperature monitoring signal transmission, respectively.

6. The energy-saving chip atomic clock with a vacuum-insulated structure according to claim 5, characterized in that, Both the magnetic shielding cavity and the magnetic shielding cover are made of permalloy sheet material through stretching.

7. The energy-saving chip atomic clock with a vacuum-insulated structure according to claim 3, characterized in that, The C-field coil is a multi-layer self-adhesive hollow coil. The external dimensions of the C-field coil are adapted to the inner cavity formed by the magnetic shielding cavity and the magnetic shielding cover, and the number of turns of the PTFE tape is 2 to 4.

8. The energy-saving chip atomic clock with a vacuum-insulated structure according to claim 6, characterized in that, The waist of the magnetic shielding cavity is welded and fixed to the main control circuit board through the double row of solder pads, and the magnetic shielding cover is fixed to the magnetic shielding cavity through silicone rubber.

9. The energy-saving chip atomic clock with a vacuum-free thermal insulation structure according to claim 3, characterized in that, The MCU can receive an external 1PPS reference signal; When the external 1PPS reference signal is valid, the MCU controls the CPT physical part to be continuously powered on to maintain the CPT calibration mode, and achieves discipline by fine-tuning the CPT physical part, while synchronizing the internally output 1PPS signal; when the external 1PPS reference signal is invalid, the MCU automatically switches to alternate between CPT calibration mode and crystal oscillator timekeeping mode.

10. The energy-saving chip atomic clock with a vacuum-free thermal insulation structure according to claim 9, characterized in that, Before the atomic clock switches from CPT calibration mode to crystal oscillator timekeeping mode, the operating parameters of the CPT physical part in CPT calibration mode are recorded, and the operating parameters are used as the initial parameters when the CPT calibration mode is started next time.

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