JP6926519B2 - Light emitting element modules, atomic oscillators, electronic devices and mobiles - Google Patents

Description

The present invention relates to light emitting device modules, atomic oscillators, electronic devices and mobile objects.

Conventionally, for example, a light emitting element module including a light emitting element that emits laser light has been known.

The light emitting element module includes, for example, an optical unit having an optical element such as a semiconductor laser, a laser medium excited by the laser light from the semiconductor laser, and an optical element for converting the wavelength of the laser light from the laser medium, and an optical unit. An optical pickup device including a package is known (see Patent Document 1). In such an optical pickup device, a window is provided in the package, and the laser beam whose wavelength is converted from the optical element is emitted to the outside of the package through the window.

Japanese Unexamined Patent Publication No. 7-98881

However, in the optical pickup device according to Patent Document 1, since the window provided in the package is provided orthogonal to the emission direction of the laser light, the laser light (reflected light) reflected by the window is contained in the package. There is a problem that the laser beam returns to the semiconductor laser, which reduces the stability of the laser light emitted from the semiconductor laser (particularly, the stability of the wavelength).

On the other hand, in recent years, with the miniaturization of devices equipped with light emitting element modules, there is a high demand for miniaturization of light emitting element modules.

An object of the present invention is to provide a light emitting element module capable of reducing the influence of return light on a light emitting element while reducing the size increase, and to provide an atomic oscillator, an electronic device, and a mobile device including such a light emitting element module. To provide the body.

The above object is achieved by the following invention.
The light emitting element module of the present invention includes a light emitting element that emits light and a light emitting element.
A base having a recess in which the light emitting element is housed,
With a lid that covers the opening of the recess and is joined to the base.
The lid
A protruding portion that is provided so as to project on the side opposite to the base and has a hole through which the light passes.
The protruding portion is provided with the hole closed, and has a window portion for transmitting the light.
The surface of the window portion on the light emitting element side is inclined with respect to a surface whose normal axis is the optical axis of the light.

According to such a light emitting element module of the present invention, since the surface of the window portion on the light emitting element side is inclined with respect to the surface whose normal axis is the optical axis of light, the light from the light emitting element is emitted from the window portion. It is possible to reduce the amount of return light that is reflected and returned to the light emitting element. Further, since the window portion is provided on the protruding portion, the separation distance between the window portion and the light emitting element can be increased. Therefore, the return light can be effectively reduced in combination with the fact that the light quantity density decreases as the light from the light emitting element travels. Further, in the light emitting element module of the present invention, by providing the window portion on the protruding portion of the lid, for example, the lid does not have the protruding portion and the concave portion of the base is made large (deep) so that the window portion and the light emitting element are separated from each other. Compared with the case of increasing the distance, the entire light emitting element module can be made smaller. Therefore, according to the light emitting element module of the present invention, it is possible to reduce the influence of the return light on the light emitting element while reducing the increase in size.

In the light emitting element module of the present invention, the inclination angle of the surface of the window portion on the light emitting element side with respect to the surface whose normal axis is the optical axis of light is preferably in the range of 5 ° or more and 45 ° or less.

As a result, it is possible to reduce the influence of the return light on the light emitting element while exhibiting the necessary optical characteristics of the window portion with a relatively simple configuration.

In the light emitting element module of the present invention, it is preferable that the lid has a first portion that supports the protruding portion and a second portion that is joined to the base and is thinner than the first portion. ..

As described above, since the second portion to be joined to the base is thinner than the first portion, the lid and the base can be easily joined by seam welding or the like. Further, since the first portion is thicker than the second portion, the required mechanical strength of the lid can be ensured. Further, since the first portion is thicker than the second portion, the stress generated in the first portion when the lid and the base are joined can be reduced.

In the light emitting element module of the present invention, it is preferable that the outer peripheral surface of the protruding portion has a flat flat portion along the outer shape of the first portion when viewed from the direction along the optical axis of the light.

As a result, when the second portion of the lid and the base are joined, the protruding portion does not get in the way, and the lid and the base can be joined more easily.

In the light emitting element module of the present invention, the inner wall surface of the hole of the protruding portion has a stepped portion that is inclined with respect to a surface having the optical axis of the light as a normal and supports the window portion. Is preferable.

This makes it easy to provide the window portion at an appropriate position and inclination angle with respect to the protruding portion.

In the light emitting element module of the present invention, the width of the peak intensity of the light on the surface of the hole along the opening on the base side at an intensity of 1 / e ² (e is the base of the natural logarithm) is defined as W [mm]. Then, it is preferable that the width L [mm] of the opening on the base side of the hole satisfies the range of W <L <20 × W.

As a result, while reducing the excessive enlargement of the protruding portion, the portion (central portion) of the light emitted from the optical element excluding the portion (outer peripheral portion) where the change in energy density is large is efficiently incident in the hole. be able to.

In the light emitting element module of the present invention, it is preferable that the center of the window portion is deviated from the optical axis of the light.
As a result, it is possible to reduce the increase in size of the window portion and reduce the generation of light that does not pass through the window portion. Therefore, it is possible to reduce the increase in size of the light emitting element module and reduce the diffuse reflection of the light emitted from the window portion, which adversely affects the light emitting element and the like.

In the light emitting element module of the present invention, it is preferable that the side surface of the window portion is located outside the luminous flux of the light.
As a result, light can be passed through both main surfaces of the window portion, and diffused reflection of light on the side surface of the window portion can be reduced.

The atomic oscillator of the present invention is characterized by comprising the light emitting device module of the present invention.
According to such an atomic oscillator, since the light emitting element module capable of reducing the influence of the return light on the light emitting element while reducing the increase in size is provided, the wavelength fluctuation of the light from the light emitting element is reduced. It is possible to realize an atomic oscillator having excellent oscillation characteristics by using light.

The atomic oscillator of the present invention includes an optical element that allows the light from the light emitting element to pass through, and a holder that holds the optical element.
The holder preferably has a through hole through which the protruding portion included in the light emitting element module can be inserted.

As a result, the relative positioning between the light emitting element module and the holder can be performed easily and with high accuracy by inserting the protruding portion into the through hole of the holder. Therefore, the light emitted from the light emitting element module can be appropriately incident on the optical element.

In the atomic oscillator of the present invention, the window portion is provided between the light emitting element and the optical element.
The surface of the optical element on the window side is inclined with respect to the surface having the optical axis of the light as the normal line.
It is preferable that the center of the optical element is deviated from the optical axis of the light.
As a result, it is possible to reduce the generation of light that does not pass through the optical element while reducing the increase in size of the optical element.

The electronic device of the present invention is characterized by comprising the light emitting element module of the present invention.
According to such an electronic device, since the light emitting element module capable of reducing the influence of the return light on the light emitting element while reducing the increase in size is provided, the electronic device having high characteristics using high quality light can be provided. It can be realized.

The moving body of the present invention is characterized by comprising the light emitting element module of the present invention.
According to such a moving body, since the light emitting element module capable of reducing the influence of the return light on the light emitting element while reducing the increase in size is provided, the moving body having high characteristics using high quality light can be provided. It can be realized.

It is the schematic which shows the atomic oscillator which concerns on 1st Embodiment of this invention. It is sectional drawing side view of the atomic oscillator shown in FIG. It is a top view of the atomic oscillator shown in FIG. 2 is a cross-sectional view of a light emitting device module included in the atomic oscillator shown in FIGS. 2 and 3. It is a top view of the light emitting element module shown in FIG. It is a top view of the lid provided in the light emitting element module shown in FIG. It is the schematic which shows the light emitting element and the window part of the light emitting element module included in the atomic oscillator which concerns on 2nd Embodiment of this invention. It is a figure which shows the state which the center of the window part and the optical axis of light coincide with each other. It is the schematic which shows the modification of the arrangement of the window part shown in FIG. 7. It is the schematic which shows the light emitting element and the window part of the light emitting element module included in the atomic oscillator which concerns on 3rd Embodiment of this invention. It is the schematic which shows the modification of the window part shown in FIG. It is the schematic which shows the window part and the optical system unit of the light emitting element module included in the atomic oscillator which concerns on 4th Embodiment of this invention. It is a figure which shows the schematic structure in the case where the atomic oscillator of this invention is used for the positioning system using a GPS satellite. It is a figure which shows an example of the moving body of this invention.

Hereinafter, the light emitting device module, the atomic oscillator, the electronic device, and the mobile body of the present invention will be described in detail based on the embodiments shown in the accompanying drawings.

1. 1. Atomic Oscillator First, the atomic oscillator of the present invention (atomic oscillator including the light emitting element module of the present invention) will be described.

<First Embodiment>
FIG. 1 is a schematic view showing an atomic oscillator according to the first embodiment of the present invention.
In the atomic oscillator 10 shown in FIG. 1, when an alkali metal atom is simultaneously irradiated with two resonance lights having specific different wavelengths, a phenomenon occurs in which the two resonance lights are transmitted without being absorbed by the alkali metal atom. It is an atomic oscillator that utilizes the interference effect (CPT: Coherent Population Trapping). The phenomenon caused by this quantum interference effect is also called an electromagnetically induced transparency (EIT) phenomenon.

As shown in FIG. 1, the atomic oscillator 10 includes a light emitting element module 1, an atomic cell unit 20, an optical system unit 30 provided between the light emitting element module 1 and the atomic cell unit 20, and a light emitting element. It includes a control unit 50 that controls the operation of the module 1 and the atomic cell unit 20. Hereinafter, first, the outline of the atomic oscillator 10 will be described.

The light emitting element module 1 includes a Perche element 2, a light emitting element 3, and a temperature sensor 4. The light emitting element 3 emits linearly polarized light LL containing two types of light having different frequencies. The light LL (luminous flux) emitted by the light emitting element 3 spreads out with a predetermined radiation angle, and the cross-sectional intensity distribution of the emitted light LL has a Gaussian distribution. Here, the "radiation angle" indicates a spreading angle about the optical axis a of the optical LL as a central axis. Specifically, the "radiation angle" refers to the angle at ^{1 / e 2 of the peak intensity of the light LL.} When the cross-sectional intensity distribution of the optical LL does not form a Gaussian distribution, the "radiation angle" means an angle at half the peak intensity of the optical LL. The portion inside the radiation angle of the light LL is called a luminous flux. Further, the temperature sensor 4 detects the temperature of the light emitting element 3. Further, the Perche element 2 adjusts the temperature of the light emitting element 3 (heating or cooling the light emitting element 3).

The optical system unit 30 includes a neutral density filter 301 (optical element), a lens 302 (optical element), and a quarter wave plate 303 (optical element). The neutral density filter 301 reduces the intensity of the light LL from the light emitting element 3 described above. Further, the lens 302 adjusts the radiation angle of the light LL (for example, the light LL is a parallel light). Further, the quarter wave plate 303 converts two types of light contained in the light LL having different frequencies from linearly polarized light to circularly polarized light (right circularly polarized light or left circularly polarized light).

The atomic cell unit 20 includes an atomic cell 201, a light receiving element 202, a heater 203, a temperature sensor 204, and a coil 205.

The atomic cell 201 has light transmittance, and an alkali metal is enclosed in the atomic cell 201. The alkali metal atom has an energy level of a three-level system consisting of two different ground levels and an excited level. The light LL from the light emitting element 3 is incident on the atomic cell 201 through the neutral density filter 301, the lens 302, and the quarter wave plate 303. Then, the light receiving element 202 receives and detects the light LL that has passed through the atomic cell 201.

The heater 203 heats the alkali metal in the atomic cell 201 and puts at least a part of the alkali metal into a gas state. Further, the temperature sensor 204 detects the temperature of the atomic cell 201. The coil 205 applies a magnetic field in a predetermined direction to the alkali metal in the atomic cell 201 to Zeeman split the energy level of the alkali metal atom. When the alkali metal atom is irradiated with the circularly polarized resonance light pair as described above in the state where the alkali metal atom is Zeeman split in this way, the desired energy among the plurality of levels in which the alkali metal atom is Zeeman split is desired. The number of alkali metal atoms at the level can be relatively large relative to the number of alkali metal atoms at other energy levels. Therefore, the number of atoms that express the desired EIT phenomenon increases, the desired EIT signal becomes large, and as a result, the oscillation characteristics of the atomic oscillator 10 can be improved.

The control unit 50 includes a temperature control unit 501, a light source control unit 502, a magnetic field control unit 503, and a temperature control unit 504. The temperature control unit 501 controls the energization of the heater 203 so that the temperature inside the atomic cell 201 becomes a desired temperature based on the detection result of the temperature sensor 204. Further, the magnetic field control unit 503 controls the energization of the coil 205 so that the magnetic field generated by the coil 205 becomes constant. Further, the temperature control unit 504 controls the energization of the perche element 2 so that the temperature of the light emitting element 3 becomes a desired temperature (within the temperature range) based on the detection result of the temperature sensor 4.

The light source control unit 502 controls the frequencies of two types of light contained in the light LL from the light emitting element 3 so that the EIT phenomenon occurs based on the detection result of the light receiving element 202. Here, the EIT phenomenon occurs when these two types of light become a resonance light pair having a frequency difference corresponding to the energy difference between the two base levels of the alkali metal atom in the atomic cell 201. Further, the light source control unit 502 includes a voltage-controlled crystal oscillator (not shown) whose oscillation frequency is controlled so as to stabilize in synchronization with the control of the two types of light frequencies described above, and this voltage. The output signal of the controlled crystal oscillator (VCXO) is output as the output signal (clock signal) of the atomic oscillator 10.

The outline of the atomic oscillator 10 has been described above. Hereinafter, a more specific configuration of the atomic oscillator 10 will be described with reference to FIGS. 2 and 3.

FIG. 2 is a cross-sectional side view of the atomic oscillator shown in FIG. FIG. 3 is a plan view of the atomic oscillator shown in FIG. In the following, for convenience of explanation, the upper side in FIG. 2 is also referred to as “upper” and the lower side is also referred to as “lower”.

As shown in FIG. 2, the atomic oscillator 10 collectively includes the light emitting element module 1, the atomic cell unit 20, the optical system unit 30 holding the light emitting element module 1, and the atomic cell unit 20 and the optical system unit 30. It includes a support member 40 that supports the light emitting element module 1, a control unit 50 that is electrically connected to the light emitting element module 1 and the atomic cell unit 20, and a package 60 that houses them.

The light emitting element module 1 has a Perche element 2, a light emitting element 3, a temperature sensor 4, and a package 5 containing these. The light emitting element module 1 will be described in detail later.

The optical system unit 30 includes a neutral density filter 301, a lens 302, a quarter wave plate 303, and a holder 304 that holds them. Here, the holder 304 has a columnar through hole 305 with both ends open. The through hole 305 is a passing region of the light LL, and the neutral density filter 301, the lens 302, and the 1/4 wave plate 303 are arranged in this order in the through hole 305. As shown in FIG. 3, the neutral density filter 301 is fixed to the holder 304 with an adhesive or the like (not shown) in an inclined posture with respect to a plane whose normal axis is the optical axis a. The lens 302 and the quarter wave plate 303 are respectively fixed to the holder 304 by an adhesive or the like (not shown) in a posture along a plane whose normal axis is the optical axis a. Further, the light emitting element module 1 is attached to the end of the through hole 305 on the neutral density filter 301 side (left side in FIG. 2) by an attachment member (not shown). Such a holder 304 is made of a metal material such as aluminum and has heat dissipation. This makes it possible to efficiently dissipate heat from the light emitting element module 1.

The optical system unit 30 may omit at least one of the neutral density filter 301 and the lens 302 depending on the intensity of the light LL from the light emitting element 3, the radiation angle, and the like. Further, the optical system unit 30 may have an optical element other than the neutral density filter 301, the lens 302, and the 1/4 wave plate 303. Further, the arrangement order of the neutral density filter 301, the lens 302, and the quarter wave plate 303 is not limited to the order shown in the drawing, and is arbitrary.

The atomic cell unit 20 includes an atomic cell 201, a light receiving element 202, a heater 203, a temperature sensor 204, a coil 205, and a package 206 containing these.

A gaseous alkali metal such as rubidium, cesium, or sodium is sealed in the atomic cell 201. Further, in the atomic cell 201, a rare gas such as argon or neon and an inert gas such as nitrogen may be sealed together with the alkali metal gas as a buffer gas, if necessary.

Although not shown, the atomic cell 201 has, for example, a pair of windows forming an airtightly sealed internal space by sealing both openings of a body portion having a columnar through hole and the through hole of the body portion. It has a portion (different from the window portions 56, 56A, 56B). Here, among the pair of window portions, one window portion transmits the light LL incident on the atomic cell 201, and the other window portion transmits the light LL emitted from the atomic cell 201. .. Therefore, the constituent material of each window portion may have transparency to light LL and is not particularly limited, and examples thereof include glass materials and crystals. On the other hand, the constituent material of the body portion is not particularly limited, and examples thereof include a metal material, a resin material, a glass material, a silicon material, and a crystal. It is preferable to use a silicon material. Further, the method of joining the body portion and each window portion is determined according to these constituent materials, and is not particularly limited, but for example, a direct joining method, an anode joining method, or the like can be used.

The light receiving element 202 is arranged on the side opposite to the light emitting element module 1 with respect to the atomic cell 201. The light receiving element 202 is not particularly limited as long as it can detect the intensity of the light LL (resonant light pair) transmitted through the atomic cell 201, but is not particularly limited, and is, for example, a photodetector such as a solar cell or a photodiode. Light receiving element).

Although not shown, the heater 203 is arranged on the above-mentioned atomic cell 201 or connected to the atomic cell 201 via a heat conductive member such as metal. The heater 203 is not particularly limited as long as it can heat the atomic cell 201 (more specifically, the alkali metal in the atomic cell 201), and examples thereof include various heaters having a heat generating resistor, a Perche element, and the like. Be done.

Although not shown, the temperature sensor 204 is arranged near, for example, the atomic cell 201 or the heater 203. The temperature sensor 204 is not particularly limited as long as it can detect the temperature of the atomic cell 201 or the heater 203, and examples thereof include various known temperature sensors such as a thermistor and a thermoelectric pair.

Although not shown, the coil 205 is, for example, a solenoid-type coil that is wound around the outer circumference of the atomic cell 201, or a pair of Helmholtz-type coils that face each other via the atomic cell 201. The coil 205 generates a magnetic field in the atomic cell 201 in a direction (parallel direction) along the optical axis a of the light LL. As a result, the gap between different degenerate energy levels of the alkali metal atom in the atomic cell 201 can be widened by Zeeman splitting to improve the resolution and reduce the line width of the EIT signal. The magnetic field generated by the coil 205 may be either a DC magnetic field or an AC magnetic field, or may be a magnetic field in which a DC magnetic field and an AC magnetic field are superimposed.

Although not shown, the package 206 includes, for example, a plate-shaped substrate and a lid bonded to the substrate, and between these, the above-mentioned atomic cell 201, light receiving element 202, heater 203, and temperature sensor. It forms an airtight space that houses the 204 and the coil 205. Here, the substrate directly or indirectly supports the atomic cell 201, the light receiving element 202, the heater 203, the temperature sensor 204, and the coil 205. Further, on the outer surface of the substrate, a plurality of terminals electrically connected to the light receiving element 202, the heater 203, the temperature sensor 204, and the coil 205 are provided. On the other hand, the lid has a bottomed tubular shape with one end open, and the opening is closed by a substrate. Further, a window portion 207 having transparency to light LL is provided at the other end portion (bottom portion) of the lid body.

The constituent material of the portion other than the base of the package 206 and the window portion of the lid is not particularly limited, and examples thereof include ceramics and metal. Further, examples of the constituent material of the window portion 207 include a glass material and the like. The method of joining the substrate and the lid is not particularly limited, and examples thereof include brazing, seam welding, and energy beam welding (laser welding, electron beam welding, etc.). Further, it is preferable that the pressure inside the package 206 is lower than the atmospheric pressure. Thereby, the temperature of the atomic cell 201 can be controlled easily and with high accuracy. As a result, the characteristics of the atomic oscillator 10 can be improved.

The support member 40 has a plate shape, and the above-mentioned atomic cell unit 20 and optical system unit 30 are placed on one surface of the support member 40. The support member 40 has an installation surface 401 that follows the shape of the lower surface of the holder 304 of the optical system unit 30. A step portion 402 is formed on the installation surface 401. The step portion 402 engages with the step portion on the lower surface of the holder 304 to restrict the holder 304 from moving to the atomic cell unit 20 side (right side in FIG. 2). Similarly, the support member 40 has an installation surface 403 that follows the shape of the lower surface of the package 206 of the atomic cell unit 20. A step portion 404 is formed on the installation surface 403. The step portion 404 engages with the end surface of the package 206 (the end surface on the left side in FIG. 2) to restrict the package 206 from moving to the optical system unit 30 side (left side in FIG. 2).

In this way, the support member 40 can define the relative positional relationship between the atomic cell unit 20 and the optical system unit 30. Here, since the light emitting element module 1 is fixed to the holder 304, the relative positional relationship of the light emitting element module 1 with respect to the atomic cell unit 20 and the optical system unit 30 is also defined. Here, the package 206 and the holder 304 are fixed to the support member 40 by fixing members such as screws (not shown), respectively. Further, the support member 40 is fixed to the package 60 by a fixing member such as a screw (not shown). Further, the support member 40 is made of a metal material such as aluminum and has heat dissipation. This makes it possible to efficiently dissipate heat from the light emitting element module 1.

As shown in FIG. 3, the control unit 50 includes a circuit board 505, two connectors 506a and 506b provided on the circuit board 505, a rigid wiring board 507a connected to the light emitting element module 1, and an atom. The rigid wiring board 507b connected to the cell unit 20, the flexible wiring board 508a connecting the connector 506a and the rigid wiring board 507a, and the flexible wiring board 508b connecting the connector 506b and the rigid wiring board 507b. And a plurality of lead pins 509 penetrating the circuit board 505.

Here, an IC (Integrated Circuit) chip (not shown) is provided on the circuit board 505, and the IC chip serves as the temperature control unit 501, the light source control unit 502, the magnetic field control unit 503, and the temperature control unit 504 described above. Function. Further, the circuit board 505 has a through hole 5051 through which the above-mentioned support member 40 is inserted. Further, the circuit board 505 is supported with respect to the package 60 via a plurality of lead pins 509. The plurality of lead pins 509 are electrically connected to the circuit board 505.

The configuration for electrically connecting the circuit board 505 and the light emitting element module 1 and the configuration for electrically connecting the circuit board 505 and the atomic cell unit 20 are the connectors 506a and 506b and the rigid wiring board 507a shown in the drawings. , 507b and flexible wiring boards 508a, 508b, and may be other known connectors and wirings, respectively.

The package 60 is made of a metal material such as Kovar and has a magnetic shielding property. Thereby, it is possible to reduce the influence of the external magnetic field on the characteristics of the atomic oscillator 10. The inside of the package 60 may be decompressed or may have an atmospheric pressure.

(Detailed description of the light emitting element module)
FIG. 4 is a cross-sectional view of a light emitting device module included in the atomic oscillators shown in FIGS. 2 and 3. FIG. 5 is a plan view of the light emitting element module shown in FIG. FIG. 6 is a plan view of the lid included in the light emitting element module shown in FIG. In the following, for convenience of explanation, the upper side in FIG. 4 is also referred to as “upper” and the lower side is also referred to as “lower”.

As shown in FIG. 4, the light emitting element module 1 has a perche element 2, a light emitting element 3, a temperature sensor 4, and a package 5 containing these.

The package 5 has a base 51 having a recess 511 that opens to the upper surface, and a lid 52 that closes the opening (upper opening) of the recess 511. And an internal space S which is an airtight space for accommodating the temperature sensor 4 is formed. The inside of such a package 5 is preferably in a reduced pressure (vacuum) state. As a result, the influence of the temperature change outside the package 5 on the light emitting element 3 and the temperature sensor 4 in the package 5 can be reduced, and the temperature fluctuation of the light emitting element 3 and the temperature sensor 4 in the package 5 can be reduced. can. The package 5 does not have to be in a reduced pressure state, and may be filled with an inert gas such as nitrogen, helium, or argon.

The constituent material of the base 51 is not particularly limited, but is a material having insulating properties and suitable for making the internal space S an airtight space, for example, oxide-based ceramics such as alumina, silica, titania, and zirconia. , Nitride-based ceramics such as silicon nitride, aluminum nitride and titanium nitride, and various ceramics such as carbide-based ceramics such as silicon carbide can be used.

Further, the base 51 has a step portion 512 which is above the bottom surface of the recess 511 and is formed so as to surround the outer periphery of the bottom surface of the recess 511. As shown in FIG. 5, connection electrodes 62a, 62b, 62c, 62d, 62e, and 62f are provided on the upper surface of the step portion 512. These connection electrodes 62a, 62b, 62c, 62d, 62e, and 62f (hereinafter, also referred to as “connection electrodes 62a to 62f”) are attached to the lower surface of the base 51 via through electrodes (not shown) that penetrate the base 51, respectively. It is electrically connected to the externally mounted electrodes 61a, 61b, 61c, 61d, 61e, 61f (hereinafter, also referred to as "externally mounted electrodes 61a to 61f") provided.

The constituent materials of the connection electrodes 62a to 62f and the external mounting electrodes 61a to 61f are not particularly limited, and are, for example, gold (Au), gold alloy, platinum (Pt), aluminum (Al), aluminum alloy, and silver (Ag). ), Silver alloy, chromium (Cr), chromium alloy, nickel (Ni), copper (Cu), molybdenum (Mo), niobium (Nb), tungsten (W), iron (Fe), titanium (Ti), cobalt ( Examples thereof include metal materials such as Co), zinc (Zn), and zirconium (Zr).

Further, a frame-shaped (annular) seal ring 53 is provided on the upper end surface of the base 51. The seal ring 53 is made of, for example, a metal material such as Kovar, and is joined to the base 51 by brazing or the like. The lid 52 is joined to the base 51 via such a seal ring 53 by seam welding or the like.

As shown in FIGS. 4 and 6, the lid 52 has a plate-shaped main body portion 54, a tubular protruding portion 55 provided on the main body portion 54, and a hole formed inside the protruding portion 55. It has a window portion 56 that closes 551 (opening).

The main body portion 54 includes a first portion 54a that supports the protruding portion 55, a second portion 54b that is joined to the base 51 (more specifically, the base 51 via a seal ring 53), and a first portion. It has a third portion 54c that connects the second portions 54a and 54b. The plate surface 540 (upper surface) of the main body 54 is parallel to the surface whose normal axis is the optical axis a of the light LL emitted from the light emitting element 3. Here, the thicknesses t2 and t3 of the second and third portions 54b and 54c are thinner than the thickness t1 of the first portion 54a, respectively. Further, the thickness t2 of the second portion 54b and the thickness t3 of the third portion 54c are equal to each other. In the present embodiment, when the outer peripheral portion of the thickness t2 of the main body portion 54 is divided into two portions with the inner peripheral edge 531 of the seal ring 53 as a boundary in a plan view, the outer portion of the two portions is captured. It can be said that the second portion is 54b and the inner portion is the third portion 54c. Further, the outer peripheral portion of the first portion 54a is continuously thinned toward the third portion 54c, whereby the upper surface and the lower surface of the first portion 54a become the upper surface and the lower surface of the third portion 54c. It is continuously connected. Further, in the first portion 54a, a hole 541 penetrating in the thickness direction thereof is formed. The hole 541 allows at least a part of the light LL from the light emitting element 3 to pass through. The constituent material of the main body 54 is not particularly limited, but a metal material is preferably used, and among them, a metal material having a coefficient of linear expansion similar to that of the base 51 is preferably used. Therefore, for example, when the base 51 is a ceramic substrate, it is preferable to use an alloy such as Kovar as a constituent material of the main body 54.

The projecting portion 55 is provided in the central portion of the first portion 54a in a plan view, and is included in the first portion 54a. The protrusion 55 has, inside, a hole 551 communicating with the hole 541 of the main body portion 54 described above, and a hole 552 communicating with the hole 551 on the opposite side of the hole 541 from the hole 541. have. Each of the holes 551 and 552 allows at least a part of the light LL from the light emitting element 3 to pass through. Here, the width (diameter) of the hole 552 is larger than the width (diameter) of the hole 551, whereby a step portion 553 is formed between the hole 551 and the hole 552. The step portion 553 is inclined at an inclination angle θ with respect to the plate surface 540 of the main body portion 54 described above. In the present embodiment, the step portion 553 is inclined so as to face one side (right side in FIGS. 4 and 6) of the lid 52 in the longitudinal direction. Further, as shown in FIG. 6, on the outer peripheral surface of the protruding portion 55, a pair of curved surface portions 555 along the cylindrical surface and a pair of flat flat surfaces provided between the pair of curved surface portions 555 are provided. It has a part 554 and. The pair of flat portions 554 are along the outer shape of the first portion 54a of the main body portion 54 in a plan view.

The constituent material of such a protruding portion 55 may be different from the constituent material of the main body portion 54, but it is preferable to use a metal material having a linear expansion coefficient similar to that of the constituent material of the main body portion 54. More preferably, it is the same as the constituent material of. Further, the protruding portion 55 is formed separately from the main body portion 54 and may be joined by a known joining method, or may be integrally (collectively) formed with the main body portion 54 using a mold or the like. May be good.

Inside the hole 552, a window portion 56 made of a plate-shaped member that transmits light LL is installed. The window portion 56 is joined on the stepped portion 553 described above by a known joining method, and closes the opening on the hole 552 side of the hole 551 of the protrusion portion 55 described above. Here, as described above, since the step portion 553 is inclined with respect to the plate surface 540 of the main body portion 54 at an inclination angle θ, the window portion 56 also has an inclination angle θ with respect to the plate surface 540 of the main body portion 54. It is tilted. Therefore, in the present embodiment, the surface 560 (lower surface) of the window portion 56 on the light emitting element 3 side and the surface (upper surface) on the side opposite to the light emitting element 3 are also one side in the longitudinal direction of the lid 52 (FIGS. 4 and 4). It is inclined so as to face (right side in 6). The window portion 56 has transparency to the light LL from the light emitting element 3. The constituent material of such a window portion 56 is not particularly limited, and examples thereof include a glass material and the like. The window portion 56 may be an optical component such as a lens or a neutral density filter.

The plan view shape of the window portion 56 is not particularly limited, but the present embodiment is a hexagon. Since the plan view shape of the window portion 56 is hexagonal, the circular opening of the hole 551 is accurately formed even if the area of the window portion 56 is smaller than that in the case where the plan view shape of the window portion 56 is quadrangular. Can be closed to. Further, as compared with the case where the window portion 56 has a circular shape in a plan view, for example, when a plurality of window portions 56 are cut out from one substrate (base plate) and formed, there are few wasted portions and more windows are formed. The portion 56 can be formed.

As shown in FIG. 4, such a lid 52 is positioned by engaging the main body portion 54 and the protruding portion 55 with the holder 304 of the above-mentioned optical system unit 30. More specifically, the protruding portion 55 is inserted into the through hole 305 of the holder 304, and the plate surface 540 of the main body portion 54 abuts on the positioning surface 306 of the holder 304, so that the light emitting element 3 is in the optical axis a direction. The lid 52 and the light emitting element module 1 are positioned in the above. Further, in a state where the protruding portion 55 is inserted into the through hole 305 of the holder 304, the side surface of the protruding portion 55 (more specifically, the pair of curved surface portions 555 described above) comes into contact with the inner wall surface of the through hole 305. As a result, the lid 52 and the light emitting element module 1 are positioned in the direction perpendicular to the optical axis a of the light emitting element 3.

A perche element 2 is arranged on the bottom surface of the recess 511 of the base 51 of the package 5. The perche element 2 is fixed to the base 51 with, for example, an adhesive. As shown in FIG. 4, the Pelche element 2 has a pair of substrates 21 and 22, and a joint 23 provided between the substrates 21 and 22. The substrates 21 and 22 are each made of a material having excellent thermal conductivity, such as a metal material or a ceramic material. In addition, insulating films are provided on the surfaces of the substrates 21 and 22, as needed. The lower surface of such a substrate 21 is fixed to the base 51 of the package 5, while the upper surface of the substrate 21 is provided with a pair of terminals 24 and 25 as shown in FIG. Further, the substrate 22 is provided so as to expose a pair of terminals 24 and 25. The pair of terminals 24 and 25 are electrically connected to the connection electrodes 62a and 62b provided in the package 5 via the wires 81a and 81b which are wire wirings (bonding wires). The joint 23 is configured to include a plurality of joints of two different types of metals or semiconductors that produce a Perche effect when energized from a pair of terminals 24 and 25.

In such a Perche element 2, one of the substrates 21 and 22 is on the heat generating side and the other is on the endothermic side due to the Perche effect generated in the bonded body 23. Here, the Pelche element 2 has a state in which the substrate 21 is on the heat generating side and the substrate 22 is on the endothermic side, and a state in which the substrate 21 is on the endothermic side and the substrate 22 is on the heat absorbing side, depending on the direction of the supplied current. And can be switched. Therefore, even if the range of the environmental temperature is wide, the temperature of the light emitting element 3 and the like can be adjusted to a desired temperature (target temperature). Thereby, the adverse effect due to the temperature change (for example, the wavelength fluctuation of the optical LL) can be further reduced. Here, the target temperature of the light emitting element 3 is determined according to the characteristics of the light emitting element 3, and is not particularly limited, but is, for example, about 30 ° C. or higher and 40 ° C. or lower. In order to keep the temperature of the light emitting element 3 at this target temperature, the perche element 2 is operated in a timely manner based on the information from the temperature sensor 4, and the light emitting element 3 is heated or cooled.

Further, the Perche element 2 has a metal layer 26 provided on the upper surface of the substrate 22. The metal layer 26 is made of, for example, a metal having excellent thermal conductivity such as aluminum, gold, and silver. On the upper surface of the metal layer 26, a light emitting element 3, a temperature sensor 4, and relay members 71 and 72 are formed. Have been placed.

The light emitting element 3 is, for example, a semiconductor laser such as a vertical cavity surface emitting laser (VCSEL). A semiconductor laser can emit two types of light having different wavelengths by superimposing (modulating) a high-frequency signal on a DC bias current. The light emitting element 3 has a pair of terminals (not shown), one of which is a terminal for a drive signal and the other is a terminal for grounding. The terminal for the drive signal is electrically connected to the connection electrode 62c provided in the package 5 via the wiring 82a, the relay member 71, and the wiring 82b. On the other hand, the grounding terminal is electrically connected to the connection electrode 62d provided in the package 5 via the wiring 82c, the metal layer 26, and the wiring 82d.

The temperature sensor 4 is, for example, a temperature detecting element such as a thermistor or a thermoelectric pair. The temperature sensor 4 has a pair of terminals (not shown), one of which is a terminal for a detection signal and the other is a terminal for grounding. The terminal for the detection signal is electrically connected to the connection electrode 62e provided in the package 5 via the wiring 83a, the relay member 72, and the wiring 83b. On the other hand, the grounding terminal is electrically connected to the connection electrode 62f provided in the package 5 via the metal layer 26 and the wiring 83c.

The wirings 82a, 82b, 82c, 82d, 83a, 83b, and 83c are wire wirings (bonding wires), respectively. Here, the wiring 82b is composed of a plurality of wire wirings. As a result, the electrical resistance of the wiring 82b can be reduced, and the loss of the drive signal supplied to the light emitting element 3 can be reduced. From the same viewpoint, the wirings 82c and 82d are also composed of a plurality of wire wirings, respectively.

The relay member 71 has an insulating base portion 711 and a conductive wiring layer 712 provided on the upper surface of the base portion 711. The base 711 is made of, for example, a ceramic material. A metal layer (not shown) is bonded to the lower surface of the base portion 711, and the metal layer is bonded to the metal layer 26 via a bonding material (not shown) such as a brazing material. Further, the wiring layer 712 is made of the same material as the connection electrodes 62a to 62f described above. Further, the wiring layer 712 has a longitudinal shape and is formed on a part of the upper surface of the base portion 711. As a result, the capacitance between the wiring layer 712 and the metal layer 26 can be reduced, and even if a high-frequency signal is used as the drive signal supplied to the light emitting element 3, the loss of the drive signal can be reduced. Further, the size of the base portion 711 can be secured to some extent, and as a result, the relay member 71 can be easily mounted.

By electrically connecting the light emitting element 3 and the connection electrodes 62c and 62d via such a relay member 71 and the like, the temperatures of the wirings 82a, 82b, 82c and 82d are also adjusted by the Perche element 2. Therefore, the temperature fluctuations of the wirings 82a, 82b, 82c, and 82d are reduced, and the temperature fluctuations of the light emitting element 3 can be reduced accordingly.

The relay member 72 can be configured in the same manner as the relay member 71 described above. However, since the temperature sensor 4 does not use a high frequency signal, the wiring layer included in the relay member 72 may be provided over the entire upper surface of the base portion.

By electrically connecting the temperature sensor 4 and the connection electrodes 62e and 62f via such a relay member 72 and the like, the temperatures of the wirings 83a, 83b and 83c are also adjusted by the Perche element 2. Therefore, the temperature fluctuations of the wirings 83a, 83b, and 83c are reduced, and the temperature fluctuations of the temperature sensor 4 can be reduced accordingly. That is, the temperature sensor 4 can be made less susceptible to the influence of heat from the connection electrodes 62e and 62f. Therefore, the detection accuracy of the temperature sensor 4 can be improved, and as a result, the temperature of the light emitting element 3 can be controlled with high accuracy.

As shown in FIG. 4, the light emitting element module 1 as described above covers the light emitting element 3 that emits light LL, the base 51 having the recess 511 in which the light emitting element 3 is housed, and the opening of the recess 511. It includes a lid 52 that is joined to the base 51. Further, the lid 52 is provided so as to project on the side opposite to the base 51, and is provided by closing the protrusion 55 having a hole 551 through which the light LL passes and the hole 551 of the protrusion 55 to transmit the light LL. It has a part 56 and. The surface 560 (lower surface) of the window portion 56 on the light emitting element 3 side is inclined with respect to the surface whose normal line is the optical axis a of the optical LL, that is, the plate surface 540 of the main body portion 54.

According to the light emitting element module 1 of the present invention, the surface 560 of the window portion 56 on the light emitting element 3 side is inclined with respect to the surface (plate surface 540) having the optical axis a of the optical LL as the normal line. Therefore, the light LL from the light emitting element 3 is reflected by the window portion 56 and the return light returning to the light emitting element 3 can be reduced. Further, since the window portion 56 is provided on the protruding portion 55, the separation distance between the window portion 56 and the light emitting element 3 can be increased. Therefore, the return light can be effectively reduced in combination with the fact that the light quantity density decreases as the light LL from the light emitting element 3 progresses. Further, in the light emitting element module 1, by providing the window portion 56 in the protruding portion 55, for example, the lid 52 does not have the protruding portion 55, and the recess 511 of the base 51 is enlarged (deep) to emit light from the window portion 56. Compared with the case where the separation distance from the element 3 is increased, the entire light emitting element module 1 can be made smaller. Therefore, according to the light emitting element module 1, it is possible to reduce the influence of the return light on the light emitting element 3 while reducing the increase in size.

Further, the inclination angle θ of the surface 560 of the window portion 56 on the light emitting element 3 side with respect to the surface having the optical axis a of the optical LL as the normal is preferably in the range of 5 ° or more and 45 ° or less, and preferably 7 ° or more. It is more preferably in the range of 40 ° or less, and further preferably in the range of 10 ° or more and 30 ° or less. In particular, in the present embodiment, the inclination angle θ is 15 °. When the inclination angle θ is within the above range, the effect of the return light on the light emitting element 3 (for example, temperature) while exhibiting the necessary optical characteristics of the window portion 56 (for example, sufficient transmittance of the light LL). The wavelength fluctuation of the optical LL due to the rise) can be reduced.

The inclination direction of the surface 560 of the window portion 56 on the light emitting element 3 side is not limited to the illustration. For example, in FIG. 6, the window portion 56 is clockwise at 30 °, 60 °, 90 °, 180 °, 210. It may be arranged in a rotated state.

Further, as described above, the inner wall surface of the hole 551 of the protruding portion 55 has a stepped portion 553 that is inclined with respect to the surface having the optical axis a of the optical LL as the normal line and supports the window portion 56. doing. This makes it easy to provide the window portion 56 with respect to the protruding portion 55 at an appropriate position and the above-mentioned inclination angle θ.

Here, as described above, the light LL emitted by the light emitting element 3 is spread and emitted at a predetermined radiation angle (expansion angle with the optical axis a of the light LL as the central axis). ^{Then, when the width (diameter) at the intensity of 1 / e 2} (e is the base of the natural logarithm) of the peak intensity of the optical LL on the surface of the hole 551 along the opening on the base 51 side is W [mm]. The width L (diameter) [mm] of the opening of the hole 551 on the base 51 side preferably satisfies the range of W <L <20 × W, and satisfies the range of 2 × W <L <18 × W. It is more preferable to satisfy the range of 5 × W <L <15 × W. In particular, in this embodiment, the width L is 5.4 × W. Since the width L is within the above-mentioned range, the central portion of the light LL emitted from the light emitting element 3 excluding the outer peripheral portion where the change in energy density is large is formed while reducing the excessive increase in size of the protruding portion 55. It can be efficiently incident in 551.

Further, as described above, the lid 52 has a first portion 54a that supports the protrusion 55 and a second portion 54b that is joined to the base 51 and is thinner than the first portion 54a. As described above, since the second portion 54b joined to the base 51 is thinner than the first portion 54a, the lid 52 and the base 51 can be easily joined by seam welding or the like. Further, since the first portion 54a is thicker than the second portion 54b, the required mechanical strength of the lid 52 can be ensured. Further, since the first portion 54a is thicker than the second portion 54b, the stress generated in the first portion 54a when the lid 52 and the base 51 are joined is reduced, and the window portion 56 is separated from the protruding portion 55. That can be reduced.

Further, as described above, the outer peripheral surface of the protruding portion 55 has a flat flat portion 554 along the outer shape of the first portion 54a when viewed from the direction along the optical axis a of the optical LL. In particular, in the present embodiment, the outer peripheral surface of the protruding portion 55 has a pair of flat portions 554. As a result, when the second portion 54b of the lid 52 and the base 51 are joined, it is possible to reduce the protrusion 55 from becoming an obstacle, so that the joining of the lid 52 and the base 51 can be performed more easily. can. Further, in the present embodiment, a pair of curved surface portions 555 are provided between the pair of flat portions 554. By having such a curved surface portion 555, it is possible to secure the required mechanical strength of the protruding portion 55.

The atomic oscillator 10 has been described above. Such an atomic oscillator 10 includes a light emitting element module 1 as described above. As a result, it is possible to reduce the influence of the return light on the light emitting element 3 while reducing the increase in size. Therefore, it is possible to reduce the wavelength fluctuation of the light LL from the light emitting element 3 and realize the atomic oscillator 10 having excellent oscillation characteristics by using the light LL.

Further, as described above, the atomic oscillator 10 holds the neutral density filter 301, the lens 302, and the 1/4 wave plate 303, which are "optical elements" for passing the light LL from the light emitting element 3. It is provided with a holder 304. The holder 304 has a through hole 305 through which the protrusion 55 included in the light emitting element module 1 can be inserted. As a result, by inserting the protrusion 55 into the through hole 305 of the holder 304, the relative positioning between the light emitting element module 1 and the holder 304 can be performed easily and with high accuracy. Therefore, the light LL emitted from the light emitting element module 1 can be appropriately incident on the neutral density filter 301. Further, by bringing the main body portion 54 and the protruding portion 55 into contact with the holder 304 in this way, it is possible to reduce the temperature rise of the lid 52 by radiating heat from the holder 304 which is made of a metal material and has excellent heat dissipation. ..

<Second Embodiment>
FIG. 7 is a schematic view showing a light emitting element and a window portion of a light emitting element module included in the atomic oscillator according to the second embodiment of the present invention. FIG. 8 is a diagram showing a state in which the center of the window portion and the optical axis of light coincide with each other. FIG. 9 is a schematic view showing a modified example of the arrangement of the window portion shown in FIG. 7.
In the following description, the second embodiment will be mainly described with respect to the differences from the above-described embodiment, and the description of the same matters will be omitted. Further, in FIGS. 7, 8 and 9, the same configurations as those in the above-described embodiment are designated by the same reference numerals.

In the light emitting element module 1A shown in FIG. 7, the geometric center O56 of the window portion 56A does not coincide with the optical axis a of the optical LL and is deviated from the optical axis a. The window portion 56A is a flat plate-shaped member having a hexagonal plan view shape, like the window portion 56 in the first embodiment, and the surface 560 is inclined with respect to a surface having the optical axis a as a normal. ing. A part of the side surface 563 (outer peripheral surface) of the window portion 56A is located outside the light flux L1 of the light LL. Specifically, the edge 5601 (outer circumference) of the surface 560 (the surface on the incident side) of the window portion 56A is located outside the light flux L1 of the light LL over the entire circumference thereof. The luminous flux L1 is inside the line drawn at the radiation angle θ1. As described above, the “radiation angle” refers to the angle at ^{1 / e 2 of the peak intensity of the optical LL.} However, when the cross-sectional intensity distribution of the optical LL does not form a Gaussian distribution, the "radiation angle" means an angle at half the peak intensity of the optical LL.

Here, when the window portion 56A is changed from the state shown by the alternate long and short dash line in FIG. 8 to the state shown by the solid line in FIG. 8, that is, the position of the center O56 is not changed while the center O56 is positioned on the optical axis a. When the window portion 56A is tilted, a portion of the optical LL that does not pass through the window portion 56A is generated. In FIG. 8, the light LL does not pass through the window portion 56A in the portion distal to the light emitting element 3 of the window portion 56A (the portion on the left side of the window portion 56A shown by the solid line in FIG. 8). The portion of the light LL that does not pass through the window portion 56A may be absorbed or reflected by a portion of the lid 52 other than the window portion 56A (see FIG. 4). As a result, the amount of light LL emitted from the window portion 56A (the amount of light) may be reduced, or the portion of the light LL that does not pass through the window portion 56A may be diffusely reflected and reach the light emitting element 3 or the atomic cell 201 to have an unexpected effect. (See FIGS. 2 and 3).

In this embodiment, as described above, the window portion 56A is arranged as shown in FIG. 7 in order to reduce the influence of the portion of the light LL that does not pass through the window portion 56A. The position of the window portion 56A shown in FIG. 7 can be realized by moving the window portion 56A in the direction of the arrow A1 from the position of the window portion 56A shown by the solid line in FIG.

Specifically, as described above, the center O56 of the window portion 56A is deviated from the optical axis a of the optical LL. As a result, the size of the window portion 56A (the flat area of the surface 560) does not need to be changed from the sizes of the window portion 56A shown by the alternate long and short dash line in FIG. 8 and the window portion 56A shown by the solid line in FIG. The edge 5601 of the surface 560 of the portion 56A can be positioned outside the light flux L1 of the light LL. That is, with the size of the minimum window portion 56A, the edge 5601 of the surface 560 can be positioned outside the luminous flux L1 of the light LL. As a result, it is possible to reduce the increase in size of the window portion 56A and reduce the generation of light LL that does not pass through the window portion 56A. Therefore, the light LL (specifically, the portion having 1 / e ² or 1/2 or more of the maximum light intensity of the light LL) can be appropriately passed through the window portion 56A. As a result, it is possible to reduce the decrease in the amount of light LL emitted from the window portion 56A and the diffuse reflection of the light LL emitted from the window portion 56A, which adversely affects the light emitting element 3 and the like. Further, since the size of the window portion 56A can be reduced, a large number of window portions 56A can be manufactured from one substrate (for example, a sheet-shaped glass substrate). Therefore, it is possible to reduce the cost and improve the productivity.

Even if the edge 5601 is positioned outside the luminous flux L1 by increasing the size of the window portion 56A (flat area of the surface 560) while keeping the center O56 of the window portion 56A positioned on the optical axis a. good.

FIG. 9 shows a modified example of the window portion 56A of the present embodiment. In FIG. 9, the side surface 563 of the window portion 56A (the entire area of the side surface 563) is located outside the light flux L1 of the light LL. In other words, the edge 5601 of the surface 560 and the edge 5611 of the surface 561 (the surface on the exit side) are located outside the light flux L1 of the light LL, respectively. As a result, the light LL can pass through both main surfaces (surfaces 560 and 561) of the window portion 56A, so that diffuse reflection of the light LL on the side surface 563 of the window portion 56A can be reduced.

Here, the side surface 563 of the window portion means a surface excluding both main surfaces (surfaces 560 and 561) and a surface connecting both main surfaces (surfaces 560 and 561). The surface 560 is located on the light emitting element 3 side of the window portion 56A and is a main surface on which the light LL is incident. On the other hand, the surface 561 is located on the side opposite to the light emitting element 3 of the window portion 56A, and is the main surface from which the light LL is emitted.
Further, the fact that the side surface 563 is located outside the light flux L1 includes the case where a part of the side surface 563 is located outside the light flux L1.

The window portion 56A shown in FIGS. 7 and 9 as described above can also reduce the return light that the light LL from the light emitting element 3 is reflected by the window portion 56A and returns to the light emitting element 3.

<Third Embodiment>
FIG. 10 is a schematic view showing a light emitting element and a window portion of a light emitting element module included in the atomic oscillator according to the third embodiment of the present invention. FIG. 11 is a schematic view showing a modified example of the window portion shown in FIG.
In the following description, the third embodiment will be mainly described with respect to the differences from the above-described embodiment, and the description of the same matters will be omitted. Further, in FIGS. 10 and 11, the same configurations as those in the above-described embodiment are designated by the same reference numerals.

In the light emitting element module 1B shown in FIG. 10, coating films 565 and 566 are provided on both main surfaces (surfaces 560 and 561) of the window portion 56B. The window portion 56B has the same configuration as the window portion 56A shown in FIG. The coating films 565 and 566 are composed of, for example, an antireflection film (AR coat). As a result, it is possible to reduce the reflection of the light LL from the light emitting element 3 on the window portion 56B. Therefore, since it is possible to reduce the decrease in the amount of light LL passing through the window portion 56B, it is possible to increase the amount of light LL reaching the atomic cell 201 (see FIGS. 2 and 3). The coating films 565 and 566 are not limited to the antireflection film, and may be composed of a film having other functions.

The coating film 565 is provided on almost the entire surface (the portion excluding the edge 5601) of the surface 560 (the surface on the incident side) of the window portion 56B. Similarly, the coating film 566 is provided on almost the entire surface (the portion excluding the edge 5611) of the surface 561 (the surface on the exit side). Further, the center O565 of the coating film 565 and the center O566 of the coating film 566 are located on the central axis A56 of the window portion 56B. Further, the centers O565 and O566 are not located on the optical axis a, respectively, and are deviated from the optical axis a. The central axis A56 is an axis that passes through the center O56 of the window portion 56B and is along the thickness direction of the window portion 56B.

Further, the edge 5651 of the coating film 565 is located outside the light flux L1 of the light LL over the entire circumference thereof. Similarly, the edge 5661 of the coating film 566 is located outside the luminous flux L1 of the light LL over the entire circumference thereof. As a result, the light LL can be more appropriately passed through the coating films 565 and 566, so that the light reflected from the window portion 56B to the light emitting element 3 and the like can be reduced. Therefore, the amount of light LL that reaches the atomic cell 201 can be increased. Further, it is possible to reduce that the reflected light reaches the light emitting element 3 and the atomic cell 201 and has an adverse effect.

FIG. 11 shows a modified example of the window portion 56B provided with the coating film 565 and 566 of the present embodiment. In FIG. 11, the coating films 565 and 566 are arranged according to the regions through which the light LL passes. Specifically, the center O565 of the coating film 565 is located on the right side in FIG. 11 with respect to the central axis A56 of the window portion 56B. On the other hand, the center O566 of the coating film 566 is located on the left side in FIG. 11 with respect to the central axis A56 of the window portion 56B. That is, the center O565 of the coating film 565 and the center O566 of the coating film 566 are displaced from each other with respect to the central axis A56 with the central axis A56 in between.

Even with the window portion 56B provided with the coating films 565 and 566 shown in FIGS. 10 and 11 as described above, the light LL from the light emitting element 3 is reflected by the window portion 56B and returned to the light emitting element 3. Can be reduced.

Either one of the coating films 565 and 566 may be omitted as appropriate. However, by providing both the coating films 565 and 566, the effect of reducing the adverse effect of the reflected light can be further enhanced.

<Fourth Embodiment>
FIG. 12 is a schematic view showing a window portion and an optical system unit of a light emitting element module included in the atomic oscillator according to the fourth embodiment of the present invention.
In the following description, the fourth embodiment will be described mainly on the differences from the above-described embodiment, and the description of the same matters will be omitted. Further, in FIG. 12, the same configurations as those in the above-described embodiment are designated by the same reference numerals.

As shown in FIG. 12, in the atomic oscillator 10C, the geometric center O301 of the neutral density filter 301C included in the optical system unit 30 does not coincide with the optical axis a and is deviated from the optical axis a. .. The neutral density filter 301C is a flat plate-shaped member like the neutral density filter 301 in the first embodiment, and is inclined with respect to a plane having the optical axis a as a normal. Further, the side surface 3015 (outer peripheral surface) of the neutral density filter 301C is located outside the light flux L1 of the light LL. In other words, the edge 3012 of the surface 3011 on the window 56A side of the neutral density filter 301C and the edge 3014 of the surface 3013 on the opposite side of the window 56A of the neutral density filter 301C are the luminous fluxes of the light LL, respectively. It is located outside L1.

Here, as shown in FIG. 12, a window portion 56A is provided between the light emitting element 3 and the neutral density filter 301C as an “optical element”. The surface 3011 on the window portion 56A side of the neutral density filter 301C is inclined with respect to the surface having the optical axis a of the optical LL as the normal line, and the center O301 of the neutral density filter 301C is the optical axis of the optical LL. It is out of alignment with respect to a. As a result, similarly to the window portion 56A, the side surface 3015 of the neutral density filter 301C is moved to the outside of the light flux L1 of the light LL without excessively increasing the size of the neutral density filter 301C (the flat area of the surface 3011). Can be positioned. Therefore, it is possible to more effectively reduce the decrease in the amount of light of the light LL emitted from the neutral density filter 301C while reducing the increase in size of the neutral density filter 301C. As a result, excellent oscillation characteristics using the optical LL can be exhibited by increasing the amount of light LL that reaches the atomic cell 201 while reducing the increase in size of the atomic oscillator 10C.

In this way, when the "optical element" arranged within the range where the optical LL has a radiation angle is inclined with respect to the optical axis a, the geometry of the "optical element" with respect to the optical axis a It is effective to shift the center. Therefore, even when the "optical element" other than the window portion 56A and the neutral density filter 301C is arranged at an angle with respect to the optical axis a within such a range, the geometric of the "optical element" is geometric. It is effective to arrange the center at a position deviated from the optical axis a.

Further, even in the region after the light LL has passed through the lens 302, when the light LL has a radiation angle again (for example, when the parallel light passes through the lens and has a radiation angle), the radiation angle is obtained. It is also preferable that the geometric center of the "optical element" through which the light LL is passed is also arranged at a position deviated from the optical axis a.
The atomic oscillator 10C provided with the neutral density filter 301C shown in FIG. 12 as described above can also reduce the influence of the return light on the light emitting element 3 while reducing the increase in size, so that the light is of high quality. It is possible to realize an atomic oscillator 10C having high characteristics using LL.

2. Electronic devices The light emitting element modules 1, 1A and 1B and the atomic oscillators 10 and 10C as described above can be incorporated into various electronic devices. Hereinafter, the electronic device of the present invention will be described.

FIG. 13 is a diagram showing a schematic configuration when the atomic oscillator of the present invention is used in a positioning system using GPS satellites.

The positioning system 1100 shown in FIG. 13 includes a GPS satellite 1200, a base station device 1300, and a GPS receiving device 1400.
The GPS satellite 1200 transmits positioning information (GPS signal).

The base station device 1300 receives the positioning information from the GPS satellite 1200 with high accuracy via the antenna 1301 installed at the electronic reference point (GPS continuous observation station), and the receiving device 1302. It is provided with a transmission device 1304 that transmits positioning information via the antenna 1303.

Here, the receiving device 1302 is an electronic device including the atomic oscillator 10 (light emitting element module 1) of the present invention described above as its reference frequency oscillation source. Further, the positioning information received by the receiving device 1302 is transmitted by the transmitting device 1304 in real time.

The GPS receiving device 1400 includes a satellite receiving unit 1402 that receives positioning information from the GPS satellite 1200 via the antenna 1401 and a base station receiving unit 1404 that receives the positioning information from the base station device 1300 via the antenna 1403. Be prepared.

The receiving device 1302, which is the "electronic device" included in the positioning system 1100 as described above, includes the above-mentioned light emitting element module 1 (or light emitting element modules 1A and 1B). As a result, it is possible to reduce the influence of the return light on the light emitting element 3 while reducing the increase in size. Therefore, it is possible to realize a receiving device 1302 having high characteristics using the light LL from the light emitting element 3.

The electronic device provided with the light emitting element module of the present invention is not limited to the above-mentioned one, and is, for example, a smartphone, a tablet terminal, a clock, a mobile phone, a digital still camera, an inkjet ejection device (for example, an inkjet printer), and a personal computer. (Mobile personal computer, laptop personal computer), TV, video camera, video tape recorder, car navigation device, pager, electronic notebook (including communication function), electronic dictionary, calculator, electronic game device, word processor, work Stations, videophones, security TV monitors, electronic binoculars, POS terminals, medical equipment (eg electronic thermometers, blood pressure monitors, blood glucose meters, electrocardiogram measuring devices, ultrasonic diagnostic devices, electronic endoscopes), fish finder, various measurements It can be applied to equipment, instruments (for example, instruments of vehicles, aircraft, ships), flight simulators, terrestrial digital broadcasting, mobile phone base stations, and the like.

3. 3. Mobile FIG. 14 is a diagram showing an example of the mobile body of the present invention.

In this figure, the moving body 1500 has a vehicle body 1501 and four wheels 1502, and is configured to rotate the wheels 1502 by a power source (engine) (not shown) provided on the vehicle body 1501. An atomic oscillator 10 (light emitting element module 1) is built in such a moving body 1500.

The mobile body 1500 as described above includes the above-mentioned light emitting element module 1 (or light emitting element modules 1A and 1B). As a result, it is possible to reduce the influence of the return light on the light emitting element 3 while reducing the increase in size. Therefore, it is possible to realize a mobile body 1500 having high characteristics using the light LL from the light emitting element 3.

The light emitting device module, atomic oscillator, electronic device, and mobile body of the present invention have been described above based on the illustrated embodiments, but the present invention is not limited thereto.

Further, the configuration of each part of the present invention can be replaced with an arbitrary configuration that exhibits the same function as that of the above-described embodiment, or an arbitrary configuration can be added.

Further, in the above-described embodiment, the case where the present invention is applied to an atomic oscillator that resonates and transitions cesium or the like by utilizing the quantum interference effect of two types of light having different wavelengths has been described, but the present invention is limited to this. However, it can also be applied to an atomic oscillator that makes a resonance transition of rubidium or the like by utilizing the double resonance phenomenon of light and microwave.

Further, in the above-described embodiment, the case where the light emitting element module of the present invention is used for the atomic oscillator has been described as an example, but the present invention is not limited to this, and can be used for any device using the light emitting element. For example, the light emitting element module of the present invention can also be applied to a magnetic sensor, a quantum memory, and the like.

1 ... light emitting element module, 2 ... Perche element, 3 ... light emitting element, 4 ... temperature sensor, 5 ... package, 10 ... atomic oscillator, 20 ... atomic cell unit, 21 ... substrate, 22 ... substrate, 23 ... junction, 24 ... Terminal, 25 ... Terminal, 26 ... Metal layer, 30 ... Optical system unit, 40 ... Support member, 50 ... Control unit, 51 ... Base, 52 ... Lid, 53 ... Seal ring, 54 ... Main body, 54a ... First Part, 54b ... 2nd part, 54c ... 3rd part, 55 ... Protruding part, 56 ... Window part, 60 ... Package, 61a ... External mounting electrode, 61b ... External mounting electrode, 61c ... External mounting electrode, 61d ... External mounting Electrodes, 61e ... Externally mounted electrodes, 61f ... Externally mounted electrodes, 62a ... Connection electrodes, 62b ... Connection electrodes, 62c ... Connection electrodes, 62d ... Connection electrodes, 62e ... Connection electrodes, 62f ... Connection electrodes, 71 ... Relay members, 72 ... Relay member, 81a ... Wiring, 81b ... Wiring, 82a ... Wiring, 82b ... Wiring, 82c ... Wiring, 82d ... Wiring, 83a ... Wiring, 83b ... Wiring, 83c ... Wiring, 201 ... Atomic cell, 202 ... Light receiving element, 203 ... heater, 204 ... temperature sensor, 205 ... coil, 206 ... package, 207 ... window, 301 ... dimming filter (optical element), 302 ... lens (optical element), 303 ... 1/4 wavelength plate (optical element) ), 304 ... Holder (heat dissipation member), 305 ... Through hole, 306 ... Positioning surface, 401 ... Installation surface, 402 ... Step part, 403 ... Installation surface, 404 ... Step part, 501 ... Temperature control unit, 502 ... Light source control Unit, 503 ... Magnetic field control unit, 504 ... Temperature control unit, 505 ... Circuit board, 506a ... Connector, 506b ... Connector, 507a ... Rigid wiring board, 507b ... Rigid wiring board, 508a ... Flexible wiring board, 508b ... Flexible wiring board , 509 ... Lead pin, 511 ... Recessed portion, 512 ... Stepped portion, 513 ... Inner peripheral edge, 540 ... Plate surface, 541 ... Hole, 551 ... Hole, 552 ... Hole, 535 ... Stepped portion, 554 ... Flat portion, 555 ... Curved portion , 560 ... surface, 711 ... base, 712 ... wiring layer, 1100 ... positioning system, 1200 ... GPS satellite, 1300 ... base station device, 1301 ... antenna, 1302 ... receiving device, 1303 ... antenna, 1304 ... transmitting device, 1400 ... GPS receiver, 1401 ... antenna, 1402 ... satellite receiver, 1403 ... antenna, 1404 ... base station receiver, 1500 ... moving body, 1501 ... body, 1502 ... wheels, 5051 ... through hole, LL ... light, S ... inside Space, a ... Optical axis, θ ... Tilt angle, L ... Width, t1 ... Thickness, t2 ... Thickness, t3 ... Thickness, 1A ... Neutral density element module, 1B ... Neutral density element module, 10C ... Atomic oscillator, 56A ... Window section, 56B ... Window, 301C ... Neutral density filter, 561 ... Surface, 563 ... Side, 565 ... Coating film, 566 ... Coating film, 3011 ... Surface, 3012 ... Edge, 3013 ... Surface, 3014 ... Edge, 3015 ... Side, 5601 ... Edge, 5611 ... Edge, 5651 ... Edge, 5661 ... Edge, A1 ... Arrow, A56 ... Central axis, L1 ... Luminous flux, O301 ... Center, O56 ... Center, O565 ... Center, O566 ... Center, θ1 ... Radiation angle

Claims (11)

A light emitting element that emits light and
A base having a recess in which the light emitting element is housed,
With a lid that covers the opening of the recess and is joined to the base.
The lid
A protruding portion that is provided so as to project on the side opposite to the base and has a hole through which the light passes.
A window portion provided by closing the hole in the protruding portion and transmitting the light, and a window portion
The first portion supporting the protrusion and
It has a second portion that is joined to the base and is thinner than the first portion .
The outer peripheral surface of the protruding portion is viewed from the direction along the optical axis of the light.
A pair of curved parts and
It has a pair of flat portions that are arranged between the pair of curved portions and that follow the outer shape of the first portion.
A light emitting element module characterized in that the surface of the window portion on the light emitting element side is inclined with respect to a surface having the optical axis of the light as a normal. The light emitting element module according to claim 1, wherein the inclination angle of the surface of the window portion on the light emitting element side with respect to the surface having the optical axis of light as the normal is within the range of 5 ° or more and 45 ° or less. According to claim 1 or 2 , the inner wall surface of the hole of the protruding portion has a stepped portion that is inclined with respect to a surface having the optical axis of the light as a normal and supports the window portion. The light emitting element module described. When the width of the peak intensity of the light on the surface along the opening on the base side of the hole at the intensity of 1 / e2 (e is the base of the natural logarithm) is W [mm], the base side of the hole. The light emitting element module according to any one of claims 1 to 3 , wherein the width L [mm] of the opening is within the range of W <L <20 × W. The light emitting element module according to any one of claims 1 to 4 , wherein the center of the window portion is deviated from the optical axis of the light. The light emitting element module according to claim 5 , wherein the side surface of the window portion is located outside the luminous flux of the light. An atomic oscillator comprising the light emitting device module according to any one of claims 1 to 6. An optical element for passing the light from the light emitting element and a holder for holding the optical element are provided.
The atomic oscillator according to claim 7 , wherein the holder has a through hole through which the protruding portion included in the light emitting element module can be inserted. The window portion is provided between the light emitting element and the optical element.
The surface of the optical element on the window side is inclined with respect to the surface having the optical axis of the light as the normal line.
The atomic oscillator according to claim 8 , wherein the center of the optical element is deviated from the optical axis of the light. An electronic device comprising the light emitting element module according to any one of claims 1 to 6. A mobile body including the light emitting element module according to any one of claims 1 to 6.

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