Photo-excited magnetic sensor module

Abstract

The present invention provides a photo-excited magnetic sensor module that can reduce power consumption and lower the temperature on its outer surface. [Solution] The optically excited magnetic sensor module comprises a cell unit 2 and a housing 3 that houses the cell unit 2. The cell unit 2 has a cell 11 containing an alkali metal, a heater 12 for heating the cell 11, and a heat insulating member 13 disposed on the outside of the cell 11. The contact interface S1 between the cell unit 2 and the housing 3 has a contact portion 38 where the cell unit 2 contacts the housing 3, and a separation portion 39 where the cell unit 2 separates from the housing 3 and an air layer A is formed between the cell unit 2 and the housing 3.

Description

Technical Field

[0001] The present invention relates to a photoexcited magnetic sensor module.

Background Art

[0002] As this type of technology, for example, Patent Document 1 describes a magnetic field measurement device including a gas cell filled with an alkali metal, a heater for heating the gas cell, and a light irradiation means for irradiating probe light.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a photoexcited magnetic sensor module, an alkali metal in the cell is heated by a heater, and a change in the magnetic field in the cell is detected using probe light in a state where the inside of the cell is filled with alkali metal vapor. For such a photoexcited magnetic sensor module, it may be required to reduce the power consumption of the heater and to lower the temperature on the outer surface of the photoexcited magnetic sensor module.

[0005] Therefore, an object of the present invention is to provide a photoexcited magnetic sensor module capable of reducing power consumption and lowering the temperature on the outer surface.

Means for Solving the Problems

[0006] The photo-excited magnetic sensor module of the present invention is [1] "a photo-excited magnetic sensor module comprising a cell unit and a housing that houses the cell unit, wherein the cell unit has a cell containing an alkali metal, a heater for heating the cell, and a heat insulating member disposed on the outside of the cell, and the contact interface between the cell unit and the housing has a contact portion in which the cell unit contacts the housing and a separation portion in which the cell unit separates from the housing and an air layer is formed between the cell unit and the housing."

[0007] In this photo-excited magnetic sensor module, the contact interface between the cell unit and the housing has a contact portion where the cell unit contacts the housing, and a separation portion where the cell unit separates from the housing, creating an air layer between the cell unit and the housing. This reduces the contact area (heat conduction area) between the cell unit and the housing, suppressing heat conduction and improving thermal insulation performance. As a result, heat is less likely to escape from the cell, reducing the power consumption of the heater when heating to the target temperature. In addition, since heat from the cell is less likely to be transferred to the outer surface of the photo-excited magnetic sensor module, the temperature of the outer surface of the photo-excited magnetic sensor module can be reduced when the cell is heated to the target temperature. Therefore, this photo-excited magnetic sensor module can reduce power consumption and lower the temperature of the outer surface.

[0008] The photo-excited magnetic sensor module of the present invention may also be [2] "the photo-excited magnetic sensor module according to [1], wherein the thermal conductivity of the material constituting the housing is smaller than the thermal conductivity of the material constituting the cell." In this case, heat conduction to the housing can be further suppressed, and the heat insulation performance can be further improved.

[0009] The photo-excited magnetic sensor module of the present invention may also be [3] "the photo-excited magnetic sensor module according to [1] or [2], wherein the cell unit further comprises a cell case housing the cell, the heater and the heat insulating member, and the contact interface between the cell case and the housing has a contact portion in which the cell case contacts the housing and a separation portion in which the cell case is separated from the housing and an air layer is formed between the cell case and the housing." In this case, since the cell unit has a cell case, the arrangement of heat insulating members and the like can be made easier.

[0010] The photo-excited magnetic sensor module of the present invention may also be [4] "the photo-excited magnetic sensor module according to [3] in which the thermal conductivity of the material constituting the cell case is smaller than the thermal conductivity of the material constituting the cell." In this case, heat conduction through the cell case can be suppressed, and the heat insulation performance can be further improved.

[0011] The photo-excited magnetic sensor module of the present invention may also be the photo-excited magnetic sensor module according to [3] or [4], wherein the contact interface between the heat insulating member and the cell case is provided with an additional contact portion where the heat insulating member contacts the cell case, and an additional separation portion where the heat insulating member separates from the cell case to form an air layer between the heat insulating member and the cell case. In this case, heat conduction can be suppressed not only at the contact interface between the cell case and the housing, but also at the contact interface between the heat insulating member and the cell case, thereby further enhancing the heat insulating performance.

[0012] The photo-excited magnetic sensor module of the present invention may also be [6] "the photo-excited magnetic sensor module according to [1], wherein the cell unit is arranged in the housing such that the heat insulating member is in direct contact with the housing, and the contact interface between the heat insulating member and the housing has a contact portion in which the heat insulating member contacts the housing, and a separation portion in which the heat insulating member is separated from the housing so that an air layer is formed between the heat insulating member and the housing." In this case, the cell case can be omitted, and the number of parts can be reduced.

[0013] The optically excited magnetic sensor module of the present invention may also be [7] "an optically excited magnetic sensor module according to any one of [1] to [5], wherein the contact surface of the housing with the cell unit has an uneven surface formed thereon, and the housing contacts the cell unit at the uneven surface, thereby forming the contact portion and the separation portion." In this case, the uneven surface formed on the housing can constitute the contact portion and the separation portion.

[0014] The photo-excited magnetic sensor module of the present invention may also be [8] "the photo-excited magnetic sensor module according to [5], wherein the contact surface of the cell case with the heat insulating member has an uneven surface formed thereon, and the cell case contacts the heat insulating member at the uneven surface, thereby forming the additional contact portion and the additional separation portion." In this case, the additional contact portion and the additional separation portion can be formed by the uneven surface formed on the cell case.

[0015] The optically excited magnetic sensor module of the present invention may also be [9] "an optically excited magnetic sensor module according to any one of [1] to [8] wherein the area of ​​the separation portion is larger than the area of ​​the contact portion." In this case, the proportion of the separation portion can be increased, and the thermal insulation performance can be effectively improved.

[0016] The photo-excited magnetic sensor module of the present invention may also be

[10] "the photo-excited magnetic sensor module according to [9], wherein the ratio of the area of ​​the separation portion to the area of ​​the contact portion is 9 or more." In this case, the proportion of the separation portion can be increased, and the thermal insulation performance can be effectively improved.

[0017] The photo-excited magnetic sensor module of the present invention may also be

[11] "the photo-excited magnetic sensor module according to any one of [1] to

[10] wherein the thickness of the air layer is smaller than the thickness of the heat insulating member." In this case, it is possible to suppress the occurrence of air convection and the resulting increase in thermal conductivity in the air layer, thereby effectively improving the heat insulating performance.

[0018] The photo-excited magnetic sensor module of the present invention may also be the photo-excited magnetic sensor module according to

[11] , wherein the thickness of the air layer is 1 mm or less. In this case, it is possible to suppress the occurrence of air convection and the resulting increase in thermal conductivity in the air layer, thereby effectively improving the heat insulation performance.

[0019] The optically excited magnetic sensor module of the present invention may also be

[13] "the optically excited magnetic sensor module according to any one of [1] to

[12] , wherein the contact portion is formed to extend in a straight line." In this case, the proportion of the separation portion can be increased, and the thermal insulation performance can be effectively improved.

[0020] The photo-excited magnetic sensor module of the present invention may also be

[14] "the photo-excited magnetic sensor module according to any one of [1] to

[12] , wherein the contact portion is formed in a grid shape." In this case, the proportion of the separation portion can be increased, and the thermal insulation performance can be effectively improved.

[0021] The photo-excited magnetic sensor module of the present invention may also be

[15] "the photo-excited magnetic sensor module according to any one of [1] to

[12] , wherein the contact portion is formed in a point shape." In this case, the proportion of the separation portion can be increased, and the thermal insulation performance can be effectively improved. Furthermore, the contact portion and the separation portion can be easily formed in a planar shape, and the arrangement of the cell unit with respect to the housing can be facilitated.

[0022] The optically excited magnetic sensor module of the present invention may also be

[16] "the optically excited magnetic sensor module according to any one of [1] to

[12] , wherein the contact portion and the separation portion are configured by arranging a plurality of the contact portions or separation portions having the same shape as each other along two directions that are orthogonal to each other." In this case, the contact portion and the separation portion can be easily formed in a planar shape, and the arrangement of the cell unit with respect to the housing can be facilitated.

[0023] The photoexcited magnetic sensor module of the present invention may be the one described in

[17] "The contact portion and the separation portion are constituted by roughening the contact surface of the housing with the cell unit or the contact surface of the cell unit with the housing, the photoexcited magnetic sensor module according to any one of [1] to

[12] ". In this case, the ratio of the separation portion can be increased, and the heat insulation performance can be effectively enhanced.

[0024] The photoexcited magnetic sensor module of the present invention may be the one described in

[18] "The contact portion and the separation portion are constituted by arranging a sheet member having openings formed in a predetermined arrangement pattern between the cell unit and the housing, the photoexcited magnetic sensor module according to any one of [1] to

[16] ". In this case, the contact portion and the separation portion can be constituted by the sheet member.

Advantages of the Invention

[0025] According to the present invention, it is possible to provide a photoexcited magnetic sensor module capable of reducing power consumption and lowering the temperature on the outer surface.

Brief Description of the Drawings

[0026] [Figure 1] It is a diagram for explaining the operation of the photoexcited magnetic sensor module. [Figure 2] (a) is a perspective view of the photoexcited magnetic sensor module, and (b) is a perspective view of the photoexcited magnetic sensor module with the outer cover removed. [Figure 3] It is a perspective view of the photoexcited magnetic sensor module with the housing lid portion of the housing removed from FIG. 2(b). [Figure 4] It is a cross-sectional view taken along the line IV-IV of FIG. 3. [Figure 5] It is a plan view of the photoexcited magnetic sensor module with the case lid portion of the cell case removed from FIG. 3. [Figure 6] It is an enlarged view of a part of FIG. 3. [Figure 7] This is a perspective view of the main body of the enclosure. [Figure 8] A perspective view of the casing cover. [Figure 9] This is a perspective view of the cell case itself. [Figure 10] This figure shows the simulation results for the example. [Figure 11] This figure shows the simulation results for the comparative example. [Figure 12] This figure illustrates the operation of the photo-excited magnetic sensor module according to the first modified example. [Figure 13] This is a plan view of the optically excited magnetic sensor module according to the second modified example. [Figure 14] (a), (b), (c), and (d) are diagrams illustrating examples of the arrangement of contact and separation portions. [Modes for carrying out the invention]

[0027] Embodiments of the present invention will be described in detail below with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant explanations will be omitted.

[0028] The optically pumped magnetic sensor module 1 shown in Figures 1 to 5 (hereinafter also referred to as "sensor module 1") is an optically pumped magnetic sensor (OPM) and is used, for example, for measuring biomagnetic fields. As an example, sensor module 1 can be used as a magnetoencephalograph to measure magnetic fields generated in the brain, or as a magnetocardiograph or magnetospinal meter to measure magnetic fields generated in the heart or spinal cord. [Sensor module configuration]

[0029] As shown in Figures 1 to 5, the sensor module 1 comprises a cell unit 2, a housing 3 that houses the cell unit 2, and an outer cover 4 that covers the outer surface of the housing 3. The cell unit 2 has a cell 11, a heater 12, a heat insulating member 13, and a cell case 14, and is at least partially surrounded by a coil unit 15. The sensor module 1 further comprises a light source 21, a lens 22, a mirror 23, a quarter-wave plate 24, a photodetector 25, a connector member 26, and a connector cover 27. [Sensor module operation]

[0030] Referring to Figure 1, the operation of sensor module 1 (the principle of detecting magnetic field changes) will be explained. During measurement, sensor module 1 (cell 11) is placed near the object to be measured. Cell 11 is sealed with gas GS containing alkali metals. During measurement, the alkali metals in cell 11 are heated by heater 12, and cell 11 is filled with alkali metal vapor. In this state, laser light L output from light source 21 passes through cell 11. The laser light L is incident on cell 11 in a state of circular polarization by the quarter-wave plate 24. This circularly polarized laser light L causes the alkali metal vapor in cell 11 to be put into a spin-polarized state by optical pumping (photoexcitation). In other words, the laser light L functions as a pump light that puts the alkali metal vapor in cell 11 into a spin-polarized state by optical pumping.

[0031] The laser light L that has passed through cell 11 is detected by photodetector 25. At this time, the intensity of the laser light L detected by photodetector 25 (i.e., the degree to which the laser light L is absorbed by the alkali metal vapor in cell 11) changes according to the spin polarization state of the alkali metal vapor in cell 11. Here, the spin polarization state of the alkali metal vapor in cell 11 changes under the influence of the magnetic field of the object being measured. Therefore, based on the intensity of the detected laser light L, changes in the magnetic field of the object being measured can be detected. In this way, the laser light L also functions as a probe light for detecting the spin polarization state of the alkali metal vapor in cell 11. In this case, sensor module 1 is a single-laser sensor module in which the laser light L serves as both the pump light and the probe light. [Configuration of each part of the sensor module]

[0032] The configuration of each part of the sensor module 1 will be explained with reference to Figures 2 to 5. The explanation below will refer to the X direction (first direction), the Y direction perpendicular to the X direction (second direction), and the Z direction perpendicular to both the X and Y directions (third direction) shown in Figures 2 to 5. The housing 3 is formed in a roughly rectangular parallelepiped shape from, for example, a resin material, and has a housing body 3a and a housing lid 3b. Figure 2(b) shows the housing lid 3b attached, and Figure 3 shows the housing lid 3b removed. Note that in Figures 3 to 5, the recessed and uneven parts 35 formed on the housing 3 and the recessed and uneven parts 55 formed on the cell case 14, which will be described later, are not shown.

[0033] As shown in Figures 4 and 5, the housing 3 contains a cell unit arrangement section 3c where the cell unit 2 is placed, an optical component arrangement section 3f where the light source 21, lens 22, and mirror 23 are placed, and a photodetector arrangement section 3g where the photodetector 25 is placed. The optical component arrangement section 3f contains an optical path section 3h, which is the space through which the laser light L output from the light source 21 and directed toward the cell unit 2 travels. The photodetector arrangement section 3g is located on the opposite side of the optical path section 3h from the cell unit arrangement section 3c.

[0034] The light source 21 is, for example, a vertical cavity surface-emitting laser (FLA) that outputs laser light L. In this example, the light source 21 is mounted on the connector member 26.

[0035] Lens 22 aligns the laser light L output from light source 21. Mirror 23 reflects the laser light L, which has been aligned by lens 22, toward cell unit 2. A quarter-wave plate 24 is placed between mirror 23 and cell unit 2. The quarter-wave plate 24 introduces a phase difference of π / 2 (=λ / 4) between the vertically polarized components of the incident light. The quarter-wave plate 24 converts the linearly polarized laser light L output from light source 21 into circularly polarized light.

[0036] Cell unit 2 is located in cell unit arrangement section 3c. Cell unit 2 has a cell 11 filled with gas GS containing alkali metals. Details of cell unit 2 will be described later. Circularly polarized laser light L, converted by a quarter-wave plate 24, is incident on cell unit 2. The laser light L incident on cell unit 2 passes through cell 11 and is emitted from cell unit 2 toward photodetector 25. In this example, the laser light L passes through cell 11 along the X direction. The photodetector 25 is located in photodetector arrangement section 3g. The photodetector 25 is, for example, a photodiode and detects the laser light L that has passed through cell unit 2.

[0037] The connector member 26 is provided on one side of the housing 3 in the Z direction. The heater 12, coil unit 15, light source 21, and photodetector 25 are electrically connected to the connector member 26, and the connector member 26 is used for the electrical connection of each of these parts to the outside. A connector cover 27 is detachably attached to the connector member 26. As shown in Figure 2, the outer cover 4 is formed in a substantially rectangular parallelepiped shape and covers the outer surface of the housing 3, except for the surface on the side where the connector cover 27 is located (one side in the Z direction). [Cell Unit]

[0038] The details of the cell unit 2 will be explained with reference to Figures 3 to 5. As described above, the cell unit 2 has a cell 11, a heater 12, a heat insulating member 13, and a cell case 14, and is at least partially surrounded by a coil unit 15. The cell 11, heater 12, and heat insulating member 13 are housed inside the cell case 14, and the coil unit 15 is located outside the cell case 14.

[0039] Cell 11 has a main body 11a and a protrusion 11b. Cell 11 is formed of a translucent material such as glass or silicon. Cell 11 is sealed with gas GS consisting of an alkali metal and an inert gas. The alkali metal sealed in cell 11 is one or more of potassium, lithium, sodium, rubidium, and cesium. The inert gas sealed in cell 11 is one or more of helium, neon, argon, krypton, xenon, nitrogen, or hydrogen. The main body 11a is, for example, a rectangular parallelepiped container portion. The protrusion 11b is a tubular portion connected to the main body 11a, and is a portion that has been sealed after being used as a passage for gas intake and exhaust, such as for exhaust or introduction of gas GS.

[0040] The heater 12 is positioned in a state of thermal connection with the cell 11, and in this embodiment, it is provided on the surface of the main body portion 11a of the cell 11 (in this example, one surface in the Y direction). The heater 12 is configured in a sheet shape, for example, including a metal wire (resistor) that generates heat when an electric current is passed through it. In this example, the heater 12 is composed of a titanium wire and is fixed to the cell 11 by an adhesive layer. The heater 12 generates heat when an electric current is passed through it, and heats the cell 11.

[0041] The thermal insulation member 13 is positioned inside the cell case 14 so as to be located outside the cell 11. In this example, the thermal insulation member 13 is composed of a plurality of plate-shaped members 13a. The plurality of plate-shaped members 13a are arranged to fill the space between the cell 11 and the cell case 14. More specifically, in the space between the main body 11a of the cell 11 and the cell case 14, the plurality of plate-shaped members 13a are arranged to fill as little gap as possible except for the laser light L transmission area in the main body 11a, and in the space between the protrusion 11b of the cell 11 and the cell case 14, they are arranged to surround and fill the entire protrusion 11b while having a region spaced apart from the outer surface of the protrusion 11b of the cell 11. The plate-shaped members 13a are members whose thermal insulation properties are enhanced by, for example, the formation of an air layer inside. The cell case 14 is formed in a substantially rectangular parallelepiped shape from, for example, a resin material, and has a case body 14a and a case lid 14b. Figure 3 shows the case with the lid 14b attached, and Figure 5 shows the case with the lid 14b removed. Note that the hatching of the plate-shaped member 13a is omitted in Figure 4.

[0042] As shown in Figure 5, the case body 14a has a pair of first wall portions 14c facing each other in the X direction and a pair of second wall portions 14d facing each other in the Z direction. Multiple (two in this example) plate-like members 13a are placed between each first wall portion 14c and the cell 11, and multiple (four in this example) plate-like members 13a are placed between each second wall portion 14d and the cell 11. Although not shown, heat insulating members 13 (multiple plate-like members 13a) are also placed between the wall portion in the Y direction of the case body 14a (the wall portion facing the case lid portion 14b in the Y direction) and the cell 11, and between the case lid portion 14b and the cell 11. Thus, in this example, the cell 11 is housed in the cell case 14 with the heat insulating members 13 interposed between it and the cell case 14. As shown in Figure 4, one of the pair of first wall portions 14c has an aperture 14e through which the laser light L reflected by the mirror 23 and heading toward the cell 11 passes, and the other of the pair of first wall portions 14c has an aperture 14f through which the laser light L that has passed through the cell 11 passes.

[0043] As shown in Figure 3, the coil unit 15 is located outside the cell case 14. The coil unit 15 is composed of, for example, multiple coils, which generate a magnetic field acting on the cell 11. The sensor module 1 generates a magnetic field acting on the cell 11 using the coil unit 15 and detects changes in the magnetic field within the cell 11 using laser light L (probe light).

[0044] The coil unit 15 generates a corrective magnetic field, for example, so that the influence of magnetic fields other than the magnetic field being measured on the cell 11 approaches zero. For example, the coil unit 15 may generate a magnetic field in the opposite direction to the Earth's magnetic field so that the influence of the Earth's magnetic field is canceled out. Alternatively or in addition, the coil unit 15 may generate a modulated magnetic field that acts on the cell 11. For example, the coil unit 15 may generate an alternating magnetic field modulated at a predetermined frequency for increased sensitivity, or it may generate a modulated magnetic field to enable detection of the direction of magnetic field changes (positive and negative directions in each axis). In this example, the coil unit 15 is made of a flexible circuit board and is arranged to surround the four sides of the cell case 14 (cell 11) (sides of the cell case 14 other than each second wall portion 14d) (sides of the cell 11 other than the two sides in the extending direction of the protrusion 11b), and is drawn out to one side in the Z direction and electrically connected to the connector member 26. [Insulated structure]

[0045] The thermal insulation structure provided in the sensor module 1 will be described with reference to Figures 6 to 9. In the sensor module 1, a first thermal insulation structure is provided at the contact interface S1 between the cell unit 2 (cell case 14) and the housing 3, and a second thermal insulation structure is provided at the contact interface S2 between the thermal insulation member 13 and the cell case 14. The first thermal insulation structure will be described first. Although a coil unit 15 is actually placed between the cell case 14 and the housing 3 at the contact interface S1, in the following description the coil unit 15 will be considered as part of the cell case 14. Thus, the coil unit 15 can be considered to constitute part of the cell case 14.

[0046] Figure 7 is a perspective view of the housing body 3a, and Figure 8 is a perspective view of the housing lid 3b. Figure 8 shows the housing lid 3b as seen from the back (inside). The housing 3 (housing body 3a and housing lid 3b) is made of a material that is insulating and non-magnetic. The thermal conductivity of the material constituting the housing 3 is smaller than that of the material constituting the cell 11. In this example, the housing 3 is made of a resin material. Examples of resin materials constituting the housing 3 include heat-resistant resins such as PEEK (polyether ether ketone), PPS (polyphenylene sulfide), polyimide, and fluororesin.

[0047] As shown in Figure 7, the housing body 3a has sides 31, 32 defining the cell unit arrangement section 3c, a pair of sides 33, 33, and a bottom surface 34. In this example, the cell unit 2 (cell case 14) is formed in a substantially rectangular parallelepiped shape, and the cell unit arrangement section 3c is formed in a substantially rectangular parallelepiped shape corresponding to the outer shape of the cell unit 2. Sides 31, 32 face each other in the X direction, and side surfaces 33, 33 face each other in the Z direction. Sides 31, 32 are flat surfaces perpendicular to the X direction, and side surfaces 33, 33 are flat surfaces perpendicular to the Z direction. The bottom surface 34 is a flat surface perpendicular to the Y direction and is connected to sides 31-33.

[0048] As shown in Figure 6, the sides 31-33 constitute the contact interface S1 between the cell case 14 and the housing body 3a (housing 3). Although not shown, the bottom surface 34 also constitutes the contact interface S1. In other words, the housing body 3a contacts the outer surface of the cell case 14 at the sides 31-33 and the bottom surface 34. The sides 31-33 and the bottom surface 34 are the contact surfaces between the housing body 3a and the cell case 14.

[0049] As shown in Figures 6 and 7, the sides 31-33 and the bottom surface 34 have protrusions 35. In this example, the protrusions 35 include a plurality of (seven in this example) protrusions 36 formed on the sides 31, 32 and the bottom surface 34, and a plurality of (two in this example) protrusions 37 formed on the sides 33, 33.

[0050] Each protrusion 36 is formed across the side surface 31, the bottom surface 34, and the side surface 32. On the side surface 31, the protrusion 36 extends straight along the Y direction and is formed across the entire side surface 31 in the Y direction. On the bottom surface 34, the protrusion 36 extends straight along the X direction and is formed across the entire bottom surface 34 in the X direction. On the side surface 32, the protrusion 36 extends straight along the Y direction and is formed across the entire side surface 32 in the Y direction. Each protrusion 36 extends across the side surfaces 31, 32, and the bottom surface 34 so that each protrusion 36 lies on the same plane perpendicular to the Z direction. Multiple protrusions 36 are arranged at equal intervals along the Z direction. As an example, the width of the protrusions 36 is 2 mm, the height is 0.2 mm, and the arrangement pitch is 2.5 mm.

[0051] Each protrusion 37 extends straight along the Y direction on the side surface 33 and is formed across the entire surface of the side surface 33 in the Y direction. In the recessed area 35, protrusions are formed by the protrusions 36 and 37, and recesses are formed by the gaps (grooves) between adjacent protrusions 36, between adjacent protrusions 37, and between the protrusions 37 and the side surfaces 31 and 32.

[0052] As shown in Figure 6, the formation of the uneven portion 35 results in the formation of a contact interface S1 between the cell case 14 and the housing body 3a, which includes a contact portion 38 where the cell case 14 contacts the housing body 3a, and a separation portion 39 (non-contact portion) where the cell case 14 separates from the housing body 3a, forming an air layer A between the cell case 14 and the housing body 3a. The contact portion 38 and the separation portion 39 are formed when the housing body 3a contacts the outer surface of the cell case 14 at the uneven portion 35. More specifically, the housing body 3a contacts the outer surface of the cell case 14 at the top surfaces of the protrusions 36, 37 (contact portion 38), while not contacting the outer surface of the cell case 14 in the areas where the protrusions 36, 37 are not formed (separation portion 39). The air layer A is formed by the gaps between adjacent protrusions 36, the gaps between adjacent protrusions 37, and the gaps between the protrusions 37 and the sides 31, 32 (the recesses of the uneven portion 35). The air layer A is formed between the bottom surface of the recesses of the uneven portion 35 (sides 31-33 and bottom surface 34) and the outer surface of the cell case 14. The thickness of the air layer A (length in the direction perpendicular to the bottom surface of the recesses of the uneven portion 35) is smaller than the thickness of the heat insulating member 13 (the total thickness of the heat insulating member 13 or the thickness of one plate-shaped member 13a), for example, set to 1 mm or less.

[0053] As shown in Figure 8, the housing lid 3b has side surfaces 41 and 42 defining the cell unit arrangement section 3c, a pair of side surfaces 43, 43, and a top surface 44. Side surfaces 41 and 42 face each other in the X direction, and one of the side surfaces 43, 43 faces each other in the Z direction. Side surfaces 41 and 42 are flat surfaces perpendicular to the X direction, and side surfaces 43, 43 are flat surfaces perpendicular to the Z direction. The top surface 44 is a flat surface perpendicular to the Y direction and is connected to side surfaces 41 to 43.

[0054] The sides 41-43 constitute the contact interface S1 between the cell case 14 and the housing lid 3b (housing 3). The top surface 44 also constitutes the contact interface S1. In other words, the housing lid 3b contacts the outer surface of the cell case 14 at the sides 41-43 and the top surface 44. The sides 41-43 and the top surface 44 are the contact surfaces between the housing lid 3b and the cell case 14.

[0055] As shown in Figure 8, uneven surfaces 45 are formed on the side surfaces 41-43 and the top surface 44. In this example, the uneven surface 45 has multiple (seven in this example) protrusions 46 formed on the side surfaces 41, 42 and the top surface 44, and multiple (two in this example) protrusions 47 formed on the side surfaces 43, 43.

[0056] Each protrusion 46 is formed across the side surface 41, the top surface 44, and the side surface 42. On the side surface 41, the protrusion 46 extends straight along the Y direction and is formed across the entire surface 41 in the Y direction. On the top surface 44, the protrusion 46 extends straight along the X direction and is formed across the entire surface 44 in the X direction. On the side surface 42, the protrusion 46 extends straight along the Y direction and is formed across the entire surface 42 in the Y direction. Each protrusion 46 extends across the side surfaces 41, 42, and the top surface 44 so as to be located on the same plane perpendicular to the Z direction. Multiple protrusions 46 are arranged at equal intervals along the Z direction. When the housing lid 3b is combined with the housing body 3a to form the housing 3, the multiple protrusions 46 are continuous with each of the multiple protrusions 36, forming a single continuous protrusion. Each of these continuous protrusions is located on the same plane perpendicular to the Z direction.

[0057] The protrusions 47 extend straight along the Y direction on the side surface 43 and are formed across the entire surface of the side surface 43 in the Y direction. In the concave and concave portions 45, the protrusions 46 and 47 form the protrusions, and the gaps (grooves) between adjacent protrusions 46 and the gaps (grooves) between the protrusions 47 and the side surfaces 41 and 42 form the concave portions.

[0058] Similar to the case of the uneven portion 35, the formation of the uneven portion 45 results in the formation of a contact portion 38 at the contact interface S1 between the cell case 14 and the housing lid portion 3b, where the cell case 14 contacts the housing lid portion 3b, and a separation portion 39 where the cell case 14 separates from the housing lid portion 3b, forming an air layer A between the cell case 14 and the housing lid portion 3b. These contact portion 38 and separation portion 39 are formed by the housing lid portion 3b contacting the outer surface of the cell case 14 at the uneven portion 45. More specifically, the housing lid portion 3b contacts the outer surface of the cell case 14 at the top surfaces of the protrusions 46, 47 (contact portion 38), while not contacting the outer surface of the cell case 14 in the areas where the protrusions 46, 47 are not formed (separation portion 39).

[0059] In the entire contact interface S1, the area of ​​the separation portion 39 is larger than the area of ​​the contact portion 38, and the ratio of the area of ​​the separation portion 39 to the area of ​​the contact portion 38 is 9 or more. That is, the area of ​​the separation portion 39 is 9 times or more the area of ​​the contact portion 38. Furthermore, in each of the side surfaces 31-33, the bottom surface 34, side surfaces 41-43, and the top surface 44, the ratio of the area of ​​the separation portion 39 to the area of ​​the contact portion 38 is 9 or more.

[0060] Next, a second heat insulating structure provided at the contact interface S2 between the heat insulating member 13 and the cell case 14 will be described. The cell case 14 (case body 14a and case lid 14b) is made of a material that is insulating and non-magnetic. The thermal conductivity of the material constituting the cell case 14 is smaller than the thermal conductivity of the material constituting the cell 11. In this example, the cell case 14 is made of the same resin material as the housing 3.

[0061] As shown in Figure 9, the case body 14a has a pair of side surfaces 51, 51, a pair of side surfaces 52, 52, and a bottom surface 53 that define the internal space 14g of the cell case 14. The side surfaces 51, 51 are the inner surfaces of the pair of first wall portions 14c of the case body 14a described above, and the side surfaces 52, 52 are the inner surfaces of the pair of second wall portions 14d. The side surfaces 51, 51 face each other in the X direction, and the side surfaces 52, 52 face each other in the Z direction. Side surface 51 is a flat surface perpendicular to the X direction, and side surface 52 is a flat surface perpendicular to the Z direction. The bottom surface 53 is a flat surface perpendicular to the Y direction and is connected to the side surfaces 51, 51, 52, 52. In this example, the internal space 14g is formed in a substantially rectangular parallelepiped shape. As described above, the cell 11, heater 12, and heat insulating member 13 are arranged in the internal space 14g.

[0062] As shown in Figure 6, the sides 51 and 52 constitute the contact interface S2 between the case body 14a (cell case 14) and the heat insulating member 13 (plate-shaped member 13a). Although not shown, the bottom surface 53 also constitutes the contact interface S2. In other words, the case body 14a contacts the heat insulating member 13 at the sides 51 and 52 and the bottom surface 53. The sides 51 and 52 and the bottom surface 53 are the contact surfaces between the case body 14a and the heat insulating member 13.

[0063] As shown in Figures 6 and 9, the sides 51, 52 and the bottom surface 53 have protrusions 55. In this example, the protrusions 55 include a plurality of (six in this example) protrusions 56 formed on the sides 51 and the bottom surface 53, and a plurality of (two in this example) grooves 57 formed on the side 52.

[0064] Each protrusion 56 is formed across the side surfaces 51, 51 and the bottom surface 53. The protrusion 56 extends straight along the Y direction on the side surfaces 51 and is formed across the entire surface 51 in the Y direction. The protrusion 56 extends straight along the X direction on the bottom surface 53 and is formed across the entire surface 53 in the X direction. Each protrusion 56 extends across the side surfaces 51, 51 and the bottom surface 53 so that it lies on the same plane perpendicular to the Z direction. Multiple protrusions 56 are arranged at equal intervals along the Z direction.

[0065] Two grooves 57 are formed, one on each side surface 52, 52. The grooves 57 extend straight along the Y direction on the side surface 52 and are formed over the entire surface of the side surface 52 in the Y direction. In the uneven surface 55, the protrusions 56 form the protrusions, and the gaps (grooves) between adjacent protrusions 56 form the recesses. Also, the grooves 57 form the recesses, and the parts of the side surface 52 where grooves 57 are not formed form the protrusions.

[0066] As shown in Figure 6, the formation of the uneven portion 55 results in the formation of a contact interface S2 between the case body 14a and the heat insulating member 13, which includes a contact portion 58 (additional contact portion) where the heat insulating member 13 contacts the case body 14a, and a separation portion 59 (additional separation portion) where the heat insulating member 13 separates from the case body 14a, forming an air layer B between the heat insulating member 13 and the case body 14a. The contact portion 58 and the separation portion 59 are formed when the case body 14a contacts the heat insulating member 13 at the uneven portion 55. More specifically, the case body 14a contacts the heat insulating member 13 at the top surface of the protrusion 56 (contact portion 58) and the portion of the side surface 52 where the groove portion 57 is not formed (contact portion 58), while the side surface 51 and bottom surface 53 where the protrusion 56 is not formed (separation portion 59) and the groove portion 57 (separation portion 59) do not contact the heat insulating member 13. The air layer B is formed by the gaps between adjacent protrusions 56 and the grooves 57 (recesses of the uneven portion 35). The air layer B is formed between the bottom surface (sides 51, 52 and bottom surface 53) of the recesses of the uneven portion 55 and the heat insulating member 13. The thickness of the air layer B (length in the direction perpendicular to the bottom surface of the recesses of the uneven portion 55) is smaller than the thickness of the heat insulating member 13 (the total thickness of the heat insulating member 13 or the thickness of one plate-like member 13a), for example, set to 1 mm or less.

[0067] The case lid portion 14b is formed in a flat plate shape and has a surface (top surface) that defines the internal space 14g (not shown). This surface is, for example, a flat surface that faces the bottom surface 53 of the case body portion 14a in the Y direction. This surface is the contact surface between the case lid portion 14b and the heat insulating member 13 and constitutes the contact interface S2. Multiple protrusions having the same configuration as the protrusion portion 56 are formed on this surface, and these protrusions form an uneven surface. Similar to the case of the uneven surface 55, the formation of this uneven surface creates a contact portion 58 (additional contact portion) where the heat insulating member 13 contacts the case lid portion 14b, and a separation portion 59 (additional separation portion) where the heat insulating member 13 separates from the case lid portion 14b and an air layer B is formed between the heat insulating member 13 and the case lid portion 14b.

[0068] In the entire contact interface S2, the area of ​​the separation portion 59 is larger than the area of ​​the contact portion 58, and the ratio of the area of ​​the separation portion 59 to the area of ​​the contact portion 58 is 9 or more. That is, the area of ​​the separation portion 59 is 9 times or more the area of ​​the contact portion 58. Furthermore, in each of the above surfaces of the side surfaces 51, 52, the bottom surface 53, and the case lid portion 14b, the ratio of the area of ​​the separation portion 59 to the area of ​​the contact portion 58 is 9 or more.

[0069] Figures 10 and 11 show the simulation results for the example and comparative example. The example shown in Figure 10 corresponds to the sensor module 1 provided with the first and second heat insulating structures described above. The comparative example shown in Figure 11 corresponds to the case where the first and second heat insulating structures are not provided in the sensor module 1, and the inner surfaces of the housing 3 and cell case 14 are formed flat. In the example and comparative example, the cell 11 was heated by the heater 12 so that the temperature inside the cell 11 was equal (so that the temperature inside the cell 11 reached a predetermined target temperature). The heat convection in the air was 7 W / (m 2 ·K)

[0070] In the example, the power consumption of heater 12 was 0.14W. The surface temperature of cell 11 was 151.0°C, and the surface temperature of sensor module 1 (surface temperature of outer cover 4) was 31.6°C. In the comparative example, the power consumption of heater 12 was 0.225W. The surface temperature of cell 11 was 151.2°C, and the surface temperature of the outer cover was 37.0°C. From these results, it can be seen that in the example, the surface temperature of sensor module 1 was reduced by 5.4°C compared to the comparative example. It can also be seen that in the example, the power consumption of heater 12 was reduced by 0.085W (37%) compared to the comparative example. [Mechanism of Action and Effects]

[0071] In the sensor module 1, the contact interface S1 between the cell unit 2 and the housing 3 includes a contact portion 38 where the cell unit 2 contacts the housing 3, and a separation portion 39 where the cell unit 2 separates from the housing 3, forming an air layer A between the cell unit 2 and the housing 3. This reduces the contact area (heat conduction area) between the cell unit 2 and the housing 3, suppressing heat conduction and improving thermal insulation performance. As a result, heat is less likely to escape from the cell 11, thus reducing the power consumption of the heater 12 when heating to the target temperature. Furthermore, since heat from the cell 11 is less likely to be transferred to the outer surface of the sensor module 1 (the outer surface of the outer cover 4), the temperature of the outer surface of the sensor module 1 can be reduced when the cell 11 is heated to the target temperature. Therefore, the sensor module 1 can reduce power consumption and lower the temperature of the outer surface.

[0072] The cell unit 2 has a cell case 14 that houses the cell 11, heater 12, and heat insulating member 13. At the contact interface S1 between the cell case 14 and the housing 3, there is a contact portion 38 where the cell case 14 contacts the housing 3, and a separation portion 39 where the cell case 14 separates from the housing 3, forming an air layer A between the cell case 14 and the housing 3. As a result, because the cell unit 2 has a cell case 14, the arrangement of the heat insulating member 13 and the like can be made easier.

[0073] At the contact interface S2 between the heat insulating member 13 and the cell case 14, a contact portion 58 (additional contact portion) is formed where the heat insulating member 13 contacts the cell case 14, and a separation portion 59 (additional separation portion) is formed where the heat insulating member 13 separates from the cell case 14, creating an air layer B between the heat insulating member 13 and the cell case 14. As a result, heat conduction can be suppressed not only at the contact interface S1 between the cell case 14 and the housing 3, but also at the contact interface S2 between the heat insulating member 13 and the cell case 14, thereby further improving the heat insulating performance.

[0074] Uneven surfaces 35 are formed on the sides 31-33 and bottom surface 34 (contact surfaces with the cell unit 2 in the housing 3) of the housing body 3a, and uneven surfaces 45 are formed on the sides 41-43 and top surface 44 (contact surfaces with the cell unit 2 in the housing 3) of the housing lid 3b. When the housing 3 contacts the cell unit 2 at the uneven surfaces 35, 45, a contact portion 38 and a separation portion 39 are formed. Thus, the uneven surfaces 35, 45 formed on the housing 3 can constitute the contact portion 38 and the separation portion 39.

[0075] The sides 51, 52 and bottom surface 53 (contact surfaces of the cell case 14 with the heat insulating member 13) of the case body 14a have irregularities 55 formed on them, and when the cell case 14 contacts the heat insulating member 13 at the irregularities 55, contact portions 58 and separation portions 59 are formed. In addition, the surface of the case lid 14b has irregularities 55 formed on it, and when the cell case 14 contacts the heat insulating member 13 at these irregularities, contact portions 58 and separation portions 59 are formed. Thus, the irregularities 55 formed on the cell case 14 can constitute the contact portions 58 and separation portions 59.

[0076] At the contact interface S1, the ratio of the area of ​​the separation portion 39 to the area of ​​the contact portion 38 is 9 or more. Also, at the contact interface S2, the ratio of the area of ​​the separation portion 59 to the area of ​​the contact portion 58 is 9 or more. This allows for an increase in the proportion of the separation portions 39 and 59, thereby effectively improving thermal insulation performance.

[0077] The thickness of air layer A and air layer B is 1 mm or less. This suppresses the occurrence of air convection, which would increase the thermal conductivity in air layers A and B, and effectively improves the insulation performance.

[0078] The contact portion 38 (protrusions 36, 37, 46, 47) and the contact portion 58 (protrusion 56) are formed to extend in a straight line. This allows for an increase in the proportion of the separation portions 39, 59, thereby effectively improving thermal insulation performance. [Differentiation]

[0079] In the above embodiment, the sensor module 1 was configured as a one-laser system in which the laser light L served as both the pump light and the probe light. However, as shown in the first modified example in Figure 12, the sensor module 1 may be configured as a two-laser system in which the pump light L1 and the probe light L2 are independent. The sensor module 1 of the first modified example includes a light source 21A that outputs linearly polarized pump light L1 and a light source 21B that outputs circularly polarized probe light L2, instead of the light source 21. In addition, in the sensor module 1 of the first modified example, the photodetector 25 is configured as a differential detector consisting of a first photodetector 25A and a second photodetector 25B. In the case of a two-laser system, for example, the probe light L2 passes through the cell 11 along the X direction, and the pump light L1 passes through the cell 11 along the Y direction perpendicular to the X direction.

[0080] In the first modified sensor module 1, the alkali metal vapor in cell 11 is brought into a spin-polarized state by optical pumping using pump light L1 output from light source 21A. Probe light L2 output from light source 21B and passing through cell 11 is detected by photodetector 25. Here, since the spin-polarized state of the alkali metal vapor in cell 11 changes under the influence of the magnetic field of the object being measured, the polarization direction of the probe light L2 that has passed through the alkali metal vapor is changed to tilt. The first photodetector 25A detects the intensity of the light component in the deflection direction corresponding to the polarization direction of the probe light L2 before the polarization direction change, and the second photodetector 25B detects the intensity of the light component in the deflection direction corresponding to the polarization direction of the probe light L2 after the polarization direction change. This allows for the detection of the difference in light intensity between the two polarization direction components of the probe light L2. Based on this difference, the spin-polarized state of the alkali metal vapor in cell 11 can be detected, and consequently, changes in the magnetic field of the object being measured can be detected.

[0081] In the second modified example shown in Figure 13, the cell unit 2 does not have a cell case 14, and the cell unit 2 is arranged inside the housing 3 such that the heat insulating member 13 is in direct contact with the housing 3. That is, the cell unit 2 has a cell 11, a heater 12, and a heat insulating member 13, and is at least partially surrounded by a coil unit 15 (not shown). In the second modified example, the contact interface S1 is the contact interface between the heat insulating member 13 and the housing 3. There is no contact interface S2. The contact interface S1 has a contact portion 38 in which the heat insulating member 13 contacts the housing 3 (housing body portion 3a and housing lid portion 3b), and a separation portion 39 in which the heat insulating member 13 is separated from the housing 3 and an air layer A is formed between the heat insulating member 13 and the housing 3. In the second modified example, as in the above embodiment, uneven portions 35, 45 are formed on the housing 3, and the contact portion 38 and the separation portion 39 are formed when the housing 3 contacts the cell unit 2 at the uneven portions 35, 45. This second modification also reduces power consumption and lowers the temperature on the outer surface of the sensor module 1, similar to the embodiment described above.

[0082] The arrangement of the contact portions 38, 58 and separation portions 39, 59 constituting the first and second thermal insulation structures is not limited to the examples described above. In the following, an example will be given for the contact portion 38 consisting of a protrusion 36 formed on the side surface 31, but the other contact portions 38, 58 may be configured similarly. In Figures 14(a) to 14(d), the contact portion 38 is shown with hatching. In the above embodiment, the contact portion 38 was composed of multiple parts extending straight in a linear shape as shown in Figure 14(a), but the contact portion 38 may be formed in a grid shape as shown in Figure 14(b). In the arrangements of Figures 14(a) and 14(b), the proportion of separation portions 39 can be increased, and the thermal insulation performance can be effectively improved. In addition, the contact portion 38 and separation portions 39 can be easily formed in a planar shape (making it easier to align the height of the protrusion 36), and the arrangement of the cell unit 2 with respect to the housing 3 can be simplified. Furthermore, even when the contact portion 38 is in contact with a flexible member, it is easier to form an air layer A.

[0083] The contact portion 38 may be composed of multiple dot-like (point-shaped) parts, as shown in Figure 14(c). In the arrangement shown in Figure 14(c), the proportion of the separation portion 39 can be increased, effectively improving the thermal insulation performance. Also, the contact portion 38 and separation portion 39 are easily formed in a planar shape. As shown in Figure 14(d), the contact portion 38 and separation portion 39 may be composed of multiple separation portions 39 having the same shape as each other, arranged along two mutually orthogonal directions. In Figure 14(d), circular separation portions 39 are arranged along two directions (e.g., the X direction and the Z direction). In Figure 14(d), the arrangement of the contact portion 38 and separation portion 39 may be reversed. That is, the contact portion 38 and separation portion 39 may be composed of multiple contact portions 38 having the same shape as each other, arranged along two mutually orthogonal directions. In the arrangement shown in Figure 14(d), the contact portion 38 and separation portion 39 are easily formed in a planar shape.

[0084] As another variation, the contact portion 38 and the separation portion 39 may be formed by roughening the contact surface of the housing 3 with the cell unit 2. For example, the housing 3 may have irregularities formed on it by applying a textured or blasted finish to the contact surface. Alternatively, the contact portion 38 and the separation portion 39 may be formed by roughening the contact surface of the cell unit 2 with the housing 3 (for example, the outer surface of the cell case 14). In this case, the proportion of the separation portion 39 can be increased, and the thermal insulation performance can be effectively improved.

[0085] The present invention is not limited to the embodiments and modifications described above. For example, the materials and shapes of each component are not limited to those described above, but can be made from a variety of materials and shapes.

[0086] In the above embodiment, the contact portion 38 and the separation portion 39 were formed at the contact interface S1 by forming uneven portions 35 and 45 on the housing 3. However, the contact portion 38 and the separation portion 39 may also be formed at the contact interface S1 by forming uneven portions on the outer surface of the cell case 14. Alternatively, the contact portion 38 and the separation portion 39 may be formed by placing a sheet member or sealing member having a shape corresponding to the contact portion 38 and the separation portion 39 between the housing 3 and the cell case 14 (cell unit 2). As such a sheet member, for example, a sheet member with an opening formed in an arrangement pattern corresponding to the separation portion 39 in the above embodiment may be used. Alternatively, a sheet member with an opening formed in an arrangement pattern corresponding to the separation portion 39 in any of Figures 14(a) to 14(d) may be used. Similarly, for the contact interface S2, the contact portion 58 and the separation portion 59 may be formed by placing a sheet member or sealing member having a shape corresponding to the contact portion 58 and the separation portion 59 between the cell unit 2 and the heat insulating member 13. Thus, the contact portion 38 and the separation portion 39 may be formed by placing a sheet member with openings formed in a predetermined arrangement pattern between the cell unit 2 and the housing 3. Alternatively, the heat insulating member 13 may be placed not inside the cell case 14, but covering the outer circumferential surface of the cell case 14. In this case, it can be said that the cell case 14 is placed between the cell 11 and the heat insulating member 13 in the second modified example shown in Figure 13.

[0087] In the above embodiment, the second heat dissipation structure (contact portion 58 and separation portion 59) may not be provided. That is, the cell case 14 may not have an uneven portion 55 formed on it, and the inner surface of the cell case 14 may be formed flat. In the above embodiment, the first heat dissipation structure (contact portion 38 and separation portion 39) may not be provided. In this case, the cell 11, heater 12 and heat insulating member 13 can be considered to constitute a "cell unit," and the cell case 14 can be considered to constitute a "housing that houses the cell unit," and the contact portion 58 and separation portion 59 can be considered to be formed at the contact interface between the cell unit (heat insulating member 13) and the housing (cell case 14).

[0088] The width, height, and arrangement pitch of the protrusions 36, 37, 46, 47, 56 and the grooves 57 may be changed as appropriate. Instead of forming protrusions (e.g., protrusion 36) on the housing 3, the contact portion 38 and separation portion 39 may be formed by forming recesses (e.g., slits or grooves) on the housing 3. Instead of forming protrusions (e.g., protrusion 56) on the cell case 14, the contact portion 58 and separation portion 59 may be formed by forming recesses (e.g., slits or grooves) on the cell case 14. At the contact interface S1, the ratio of the area of ​​the separation portion 39 to the area of ​​the contact portion 38 may be less than 9. At the contact interface S2, the ratio of the area of ​​the separation portion 59 to the area of ​​the contact portion 58 may be less than 9. The thickness of air layer A and the thickness of air layer B may be greater than 1 mm. [Explanation of Symbols]

[0089] 1...Optical excitation magnetic sensor module, 2...Cell unit, 3...Housing, 11...Cell, 12...Heater, 13...Insulation material, 14...Cell case, 35, 45, 55...Rubber parts, 38...Contact part, 39...Separation part, 58...Contact part (additional contact part), 59...Separation part (additional separation part), A, B...Air layer, S1, S2...Contact interface.

Claims

1. Cell unit and The system comprises a housing for housing the cell unit, The aforementioned cell unit is Cells containing alkali metals, A heater for heating the aforementioned cell, The cell has a heat insulating member disposed on the outside of the cell, An optically excited magnetic sensor module, wherein the contact interface between the cell unit and the housing has a contact portion where the cell unit contacts the housing, and a separation portion where the cell unit separates from the housing and an air layer is formed between the cell unit and the housing.

2. The optically excited magnetic sensor module according to claim 1, wherein the thermal conductivity of the material constituting the housing is smaller than that of the material constituting the cell.

3. The cell unit further comprises a cell case that houses the cell, the heater, and the heat insulating member. The optically excited magnetic sensor module according to claim 1, wherein the contact interface between the cell case and the housing includes a contact portion in which the cell case contacts the housing, and a separation portion in which the cell case separates from the housing, forming an air layer between the cell case and the housing.

4. The optically excited magnetic sensor module according to claim 3, wherein the thermal conductivity of the material constituting the cell case is smaller than that of the material constituting the cell.

5. The photo-excited magnetic sensor module according to claim 3, wherein the contact interface between the heat insulating member and the cell case includes an additional contact portion in which the heat insulating member contacts the cell case, and an additional separation portion in which the heat insulating member separates from the cell case, forming an air layer between the heat insulating member and the cell case.

6. The cell unit is arranged inside the housing such that the heat insulating member is in direct contact with the housing. The optically excited magnetic sensor module according to claim 1, wherein the contact interface between the heat insulating member and the housing includes a contact portion in which the heat insulating member contacts the housing, and a separation portion in which the heat insulating member separates from the housing and an air layer is formed between the heat insulating member and the housing.

7. The contact surface of the housing with the cell unit has an uneven surface formed thereon. The optically excited magnetic sensor module according to claim 1, wherein the housing contacts the cell unit at the uneven portion, thereby forming the contact portion and the separation portion.

8. The contact surface between the cell case and the heat insulating member has an uneven surface formed thereon. The photo-excited magnetic sensor module according to claim 5, wherein the cell case contacts the heat insulating member at the uneven portion, thereby forming the additional contact portion and the additional separation portion.

9. The optically excited magnetic sensor module according to any one of claims 1 to 8, wherein the area of ​​the separation portion is larger than the area of ​​the contact portion.

10. The optically excited magnetic sensor module according to claim 9, wherein the ratio of the area of ​​the separation portion to the area of ​​the contact portion is 9 or more.

11. The photo-excited magnetic sensor module according to any one of claims 1 to 8, wherein the thickness of the air layer is smaller than the thickness of the heat insulating member.

12. The photo-excited magnetic sensor module according to claim 11, wherein the thickness of the air layer is 1 mm or less.

13. The photo-excited magnetic sensor module according to any one of claims 1 to 8, wherein the contact portion is formed to extend in a straight line.

14. The contact portion is formed in a grid pattern, as described in any one of claims 1 to 8, for the photo-excited magnetic sensor module.

15. The optically excited magnetic sensor module according to any one of claims 1 to 8, wherein the contact portion is formed in a point shape.

16. The optically excited magnetic sensor module according to any one of claims 1 to 8, wherein the contact portion and the separation portion are configured by arranging a plurality of the contact portion or the separation portion having the same shape as each other along two directions that are orthogonal to each other.

17. The photo-excited magnetic sensor module according to any one of claims 1 to 8, wherein the contact portion and the separation portion are formed by roughening the contact surface of the housing with the cell unit, or the contact surface of the cell unit with the housing.

18. The optically excited magnetic sensor module according to any one of claims 1 to 8, wherein the contact portion and the separation portion are configured by arranging a sheet member having an opening formed in a predetermined arrangement pattern between the cell unit and the housing.

Images