Patent Description:
Patent Literature <NUM> discloses an etalon portion of an interferometer including a Fabry-Perot interferometer, a holder which holds the Fabry-Perot interferometer, a Peltier element which is attached to the holder, and a vacuum container which accommodates the Fabry-Perot interferometer, the holder, and the Peltier element. In the etalon portion, the Peltier element is attached to a side of the holder with respect to an optical path leading from a light receiving window of the vacuum container to a light emitting window of the vacuum container via the Fabry-Perot interferometer.

Document <CIT> relates to a spectroscopic sensor that is provided with the following: a Fabry-Perot interference filter provided with an opening that allows transmitted light to pass therethrough along a facing axis in accordance with the distance between a first mirror and a second mirror; a photodetector that has a light-receiving section that receives light that has passed through the opening; a circuit board on which the photodetector is mounted; and a plurality of spacers that support the filter on the circuit board such that a second space that is contiguous with a first space inside the opening and contains said first space when viewed along the facing axis is formed between the filter and the circuit board. The photodetector is located inside the second space. The light receiving section is located inside the region of the second space that corresponds to the first space when viewed along the facing axis.

Document <NPL>, pages 93750F-<NUM> to <NUM> F-<NUM> relates to a Fabry-Perot based spectral sensor having a package where a tunable MEMS Fabry-Perot interference filter and a photodetector are stacked on a Peltier element. Document <NPL>, page <NUM>, relates to a two-channel thermoelectric ally cooled detector, wherein a Peltier cooler together with a thermistor are used to stabilize detector elements at a reduced temperature.

However, in the configuration described above, a Fabry-Perot interferometer is cooled from the side by a Peltier element. Therefore, when a Fabry-Perot interference filter and a light detector are accommodated in a package, the Fabry-Perot interference filter and the light detector are not uniformly cooled. Consequently, there is concern that the Fabry-Perot interference filter and the light detector may not be maintained at a uniform temperature. Furthermore, in the configuration described above, a part in the vicinity of a light receiving window of a vacuum container is cooled by the Peltier element. Therefore, when a light transmitting member is provided in an opening of the package accommodating the Fabry-Perot interference filter and the light detector, there is concern that dew condensation may occur in the light transmitting member.

An object of the present disclosure is to provide a light detection device in which dew condensation or a crack is restrained from occurring in a light transmitting member receiving light in a package, and a Fabry-Perot interference filter and a light detector accommodated in the package can be maintained at a uniform temperature.

This object is achieved by the subject-matter of the appended independent claim <NUM>, which defines the present invention. Advantageous embodiments are described in the appended dependent claims.

According to an aspect of the present disclosure, there is provided a light detection device including a Fabry-Perot interference filter having a first mirror and a second mirror with a variable distance therebetween and provided with a light transmitting region transmitting light corresponding to the distance between the first mirror and the second mirror on a predetermined line, a light detector disposed on one side with respect to the Fabry-Perot interference filter on the line and configured to detect light transmitted through the light transmitting region, a package having an opening positioned on the other side with respect to the Fabry-Perot interference filter on the line and configured to accommodate the Fabry-Perot interference filter and the light detector, a light transmitting member provided in the package such that the opening is blocked, and a temperature control element having a first region thermally connected to the Fabry-Perot interference filter and the light detector and configured to function as one of an endothermic region and an exothermic region. The first region is positioned on the one side with respect to the light detector at least on the line.

In the light detection device, the first region of the temperature control element functioning as one of the endothermic region and the exothermic region is positioned on one side with respect to the light detector at least on the line. Accordingly, for example, compared to a case in which the first region of the temperature control element is positioned on a side of the Fabry-Perot interference filter and the light detector with respect to the line, the Fabry-Perot interference filter and the light detector are maintained at a uniform temperature. Moreover, at least on the line, the Fabry-Perot interference filter and the light detector are disposed between the light transmitting member and the first region of the temperature control element. Accordingly, dew condensation, which is caused by an increase in difference between the temperature of the light transmitting member and an outside air temperature (usage environment temperature of the light detection device) when the light transmitting member is excessively cooled, is restrained from occurring in the light transmitting member. In addition, a crack, which is caused by an increase in difference between the temperature of the light transmitting member and the outside air temperature when the light transmitting member is excessively heated, is restrained from occurring in the light transmitting member. Thus, according to the light detection device, dew condensation or a crack can be restrained from occurring in the light transmitting member receiving light in the package, and the Fabry-Perot interference filter and the light detector accommodated in the package can be maintained at a uniform temperature.

According to the aspect of the present disclosure, in the light detection device, an outer edge of the opening may be positioned inside an outer edge of the Fabry-Perot interference filter when seen in a direction parallel to the line. The temperature control element may have a second region thermally connected to the package and configured to function as the other of the endothermic region and the exothermic region. In this configuration, for example, compared to a case in which the outer edge of the opening is positioned outside the outer edge of the Fabry-Perot interference filter, heat is easily transferred between the second region of the temperature control element functioning as the other of the endothermic region and the exothermic region, and the light transmitting member through the package. Thus, according to this configuration, dew condensation or a crack can be more reliably restrained from occurring in the light transmitting member.

According to the aspect of the present disclosure, in the light detection device, an outer edge of the light transmitting member may be positioned outside the outer edge of the Fabry-Perot interference filter when seen in a direction parallel to the line. In this configuration, for example, compared to a case in which the outer edge of the light transmitting member is positioned inside the outer edge of the Fabry-Perot interference filter, a contact area between the light transmitting member and the package increases, so that heat is easily transferred between the light transmitting member and the package. Thus, according to this configuration, dew condensation or a crack can be more reliably restrained from occurring in the light transmitting member.

According to the claimed invention, in the light detection device, the temperature control element is disposed inside the package. The light detector is disposed on the temperature control element. The Fabry-Perot interference filter is disposed on the temperature control element such that the light detector is positioned between the temperature control element and the Fabry-Perot interference filter. According to this configuration, the Fabry-Perot interference filter and the light detector can be efficiently maintained at a uniform temperature with a compact and simple configuration.

According to the aspect of the present disclosure, the light detection device may further include a support member configured to support a portion of a bottom surface of the Fabry-Perot interference filter outside the light transmitting region, and a heat conducting member being in contact with a side surface of the Fabry-Perot interference filter and the support member. In this configuration, for example, compared to a case in which the heat conducting member that comes into contact with the side surface of the Fabry-Perot interference filter and the support member is not provided, heat is easily transferred between the Fabry-Perot interference filter and the first region of the temperature control element with the support member interposed therebetween. Thus, according to this configuration, the Fabry-Perot interference filter and the light detector can be efficiently maintained at a uniform temperature.

According to the aspect of the present disclosure, in the light detection device, the heat conducting member may be a bonding member bonding the Fabry-Perot interference filter and the support member. According to this configuration, a held state of the Fabry-Perot interference filter on the support member can be stabilized.

According to the aspect of the present disclosure, in the light detection device, the support member may have a placement surface on which the portion of the bottom surface of the Fabry-Perot interference filter outside the light transmitting region is placed. At least a portion of the side surface of the Fabry-Perot interference filter may be positioned on the placement surface such that a portion of the placement surface is disposed outside the side surface. The heat conducting member may be disposed in a corner portion formed by the side surface and the portion of the placement surface and may be in contact with each of the side surface and the portion of the placement surface. According to this configuration, the Fabry-Perot interference filter and the light detector can be more efficiently maintained at a uniform temperature, and the held state of the Fabry-Perot interference filter on the support member can be more reliably stabilized.

According to the claimed invention, in the light detection device, the temperature control element is embedded in a wall portion of the package. According to this configuration, the volume of a space inside the package can be reduced. As a result, the Fabry-Perot interference filter and the light detector can be more efficiently maintained at a uniform temperature.

According to the present disclosure, it is possible to provide a light detection device in which dew condensation or a crack is restrained from occurring in the light transmitting member receiving light in the package, and the Fabry-Perot interference filter and the light detector accommodated in the package can be maintained at a uniform temperature.

The same reference signs are applied to the same or corresponding parts in each diagram, and duplicated parts are omitted.

As illustrated in <FIG>, a light detection device 1A includes a package <NUM>. The package <NUM> is a CAN package having a stem <NUM> and a cap <NUM>. The cap <NUM> is integrally constituted by a side wall <NUM> and a ceiling <NUM>. The ceiling <NUM> faces the stem <NUM> in a direction parallel to a predetermined line L (straight line). The stem <NUM> and the cap <NUM> are formed of metal, for example, and are joined to each other in an air-tight manner.

A temperature control element <NUM> is fixed to an inner surface of the stem <NUM>. The temperature control element <NUM> is a Peltier element, for example, and has an endothermic region 50a and an exothermic region 50b facing each other in a direction parallel to the line L. The temperature control element <NUM> is disposed inside the package <NUM> such that the exothermic region 50b is positioned on the inner surface side of the stem <NUM> and the endothermic region 50a is positioned on a side opposite thereto. Accordingly, the exothermic region 50b of the temperature control element <NUM> is thermally connected to the package <NUM>.

A wiring substrate <NUM> is fixed onto the endothermic region 50a of the temperature control element <NUM>. As a substrate material of the wiring substrate <NUM>, for example, silicon, ceramic, quartz, glass, or plastic can be used. A light detector <NUM> and a temperature compensating element such as a thermistor (not illustrated) are mounted in the wiring substrate <NUM>. Accordingly, the endothermic region 50a of the temperature control element <NUM> is thermally connected to the light detector <NUM> and a temperature compensating element (not illustrated) with the wiring substrate <NUM> interposed therebetween.

The light detector <NUM> is disposed on the line L. More specifically, the light detector <NUM> is disposed such that a center line of its light receiving portion coincides with the line L. For example, the light detector <NUM> is an infrared detector such as a quantum-type sensor using inGaAs and the like, and a thermal-type sensor using a thermopile, a bolometer, and the like. When detecting light in each of wavelength ranges, such as ultraviolet light, visible light, and near-infrared light, a silicon photodiode can be used as the light detector <NUM>, for example. One light receiving portion may be provided in the light detector <NUM>. Alternatively, a plurality of light receiving portions may be provided in an array shape. Moreover, a plurality of light detectors <NUM> may be mounted on the wiring substrate <NUM>.

A plurality of support members <NUM> are fixed onto the wiring substrate <NUM> with a heat conducting member (not illustrated) interposed therebetween. As a material of each of the support members <NUM>, for example, silicon, ceramic, quartz, glass, or plastic can be used. A Fabry-Perot interference filter <NUM> is fixed onto the plurality of support members <NUM> with a heat conducting member <NUM> interposed therebetween. Accordingly, the endothermic region 50a of the temperature control element <NUM> is thermally connected to the Fabry-Perot interference filter <NUM> with the wiring substrate <NUM>, the above-described heat conducting member (not illustrated), the plurality of support members <NUM>, and the heat conducting member <NUM> interposed therebetween.

The heat conducting member <NUM> serves as a heat conducting member transferring heat from the Fabry-Perot interference filter <NUM> to the support members <NUM> and also serves as a bonding member bonding the Fabry-Perot interference filter <NUM> and the support members <NUM>. Similarly, the heat conducting member (not illustrated) disposed between the wiring substrate <NUM> and the support members <NUM> serves as a heat conducting member transferring heat from each of the support members <NUM> to the wiring substrate <NUM> and also serves as a bonding member bonding each of the support members <NUM> and the wiring substrate <NUM>. As a material of the heat conducting member <NUM> and the heat conducting member (not illustrated), for example, a resin material (for example, the material may be a resin material, such as a silicone-based material, a urethane-based material, an epoxy-based material, an acryl-based material, and a hybrid material, which may be a conductive material or a non-conductive material) can be used.

The Fabry-Perot interference filter <NUM> is disposed on the line L. More specifically, the Fabry-Perot interference filter <NUM> is disposed such that the center line of its light transmitting region 10a coincides with the line L. The Fabry-Perot interference filter <NUM> may be supported by one support member <NUM> instead of a plurality of support members <NUM>. In addition, the Fabry-Perot interference filter <NUM> may be supported by the support member <NUM> being integrally constituted on the wiring substrate <NUM>.

A plurality of lead pins <NUM> are fixed to the stem <NUM>. More specifically, each of the lead pins <NUM> penetrates the stem <NUM> in a state in which electrical insulation properties and air-tightness with respect to the stem <NUM> are maintained. Each of an electrode pad provided in the wiring substrate <NUM>, a terminal of the temperature control element <NUM>, a terminal of the light detector <NUM>, a terminal of the temperature compensating element, and a terminal of the Fabry-Perot interference filter <NUM> is electrically connected to each of the lead pins <NUM> through a wire <NUM>. Accordingly, an electrical signal can be input and output with respect to each of the temperature control element <NUM>, the light detector <NUM>, the temperature compensating element, and the Fabry-Perot interference filter <NUM>.

An opening 2a is provided in the package <NUM>. More specifically, the opening 2a is provided in the ceiling <NUM> of the cap <NUM> such that its center line coincides with the line L. A light transmitting member <NUM> is disposed on an inner surface 6a of the ceiling <NUM> such that the opening 2a is blocked. That is, the light transmitting member <NUM> is joined to the inner surface 6a of the ceiling <NUM> in an air-tight manner. The light transmitting member <NUM> transmits light at least within a measurement wavelength range of the light detection device 1A. The light transmitting member <NUM> is a plate-shaped member including a light receiving surface 13a and a light emitting surface 13b facing each other in a direction parallel to the line L, as well as a side surface 13c. For example, the light transmitting member <NUM> is formed of glass, quartz, silicon, germanium, or plastic. The light transmitting member <NUM> is formed of a material having low heat conductivity compared to the material constituting the package <NUM>. The plate-shaped light transmitting member <NUM> may be fixed to the inner surface 6a of the ceiling <NUM>, for example, with a heat conductive bonding member.

A band-pass filter <NUM> is provided on the light emitting surface 13b of the light transmitting member <NUM>. The band-pass filter <NUM> is disposed on the light emitting surface 13b of the light transmitting member <NUM> through vapor deposition and pasting, for example. The band-pass filter <NUM> selectively transmits light within the measurement wavelength range of the light detection device 1A. For example, the band-pass filter <NUM> is a dielectric multilayer film constituted as a combination including a high refractive material such as TiO<NUM> and Ta<NUM>O<NUM>, and a low refractive material such as SiO<NUM> and MgF<NUM>.

In the light detection device 1A, the package <NUM> accommodates the temperature control element <NUM>, the wiring substrate <NUM>, the light detector <NUM>, the temperature compensating element (not illustrated), the plurality of support members <NUM>, the heat conducting member <NUM>, and the Fabry-Perot interference filter <NUM>. The light detector <NUM> is disposed on the endothermic region 50a of the temperature control element <NUM> with the wiring substrate <NUM> interposed therebetween. The Fabry-Perot interference filter <NUM> is disposed on the endothermic region 50a of the temperature control element <NUM> with the wiring substrate <NUM>, the plurality of support members <NUM>, and the heat conducting member <NUM> interposed therebetween such that the light detector <NUM> is positioned between the temperature control element <NUM> and the Fabry-Perot interference filter <NUM>.

The light detector <NUM> is positioned on one side (here, the stem <NUM> side) with respect to the Fabry-Perot interference filter <NUM> on the line L, and the endothermic region 50a of the temperature control element <NUM> is positioned on one side (here, the stem <NUM> side) with respect to the light detector <NUM> on the line L. The opening 2a of the package <NUM> and the light transmitting member <NUM> are positioned on the other side (side opposite to the one side) (here, a side opposite to the stem <NUM>) with respect to the Fabry-Perot interference filter <NUM> on the line L. The Fabry-Perot interference filter <NUM> and the light transmitting member <NUM> are separated from each other with a gap interposed therebetween.

A positional relationship and a size relationship between each of portions when seen in a direction parallel to the line L are as follows. As illustrated in <FIG>, the center line of the light receiving portion of the light detector <NUM>, the center line of the light transmitting region 10a of the Fabry-Perot interference filter <NUM>, and the center line of the opening 2a of the package <NUM> coincide with the line L. An outer edge of the light transmitting region 10a of the Fabry-Perot interference filter <NUM> and an outer edge of the opening 2a of the package <NUM> have a circular shape, for example. An outer edge of the light detector <NUM> and an outer edge of the Fabry-Perot interference filter <NUM> have a rectangular shape, for example.

The outer edge of the light transmitting region 10a of the Fabry-Perot interference filter <NUM> is positioned outside the outer edge of the light detector <NUM>. The outer edge of the opening 2a of the package <NUM> is positioned outside the outer edge of the light transmitting region 10a of the Fabry-Perot interference filter <NUM> and is positioned inside the outer edge of the Fabry-Perot interference filter <NUM>. An outer edge of the light transmitting member <NUM> is positioned outside the outer edge of the Fabry-Perot interference filter <NUM>. An outer edge of the temperature control element <NUM> is positioned outside the outer edge of the Fabry-Perot interference filter <NUM>. The expression "one outer edge is positioned outside another outer edge when seen in a predetermined direction" denotes that "one outer edge surrounds another outer edge when seen in a predetermined direction" and "one outer edge includes another outer edge when seen in a predetermined direction". In addition, the expression "one outer edge is positioned inside another outer edge when seen in a predetermined direction" denotes that "one outer edge is surrounded by another outer edge when seen in a predetermined direction" and "one outer edge is included in another outer edge when seen in a predetermined direction".

The detailed configurations of the support members <NUM>, the heat conducting member <NUM>, and the Fabry-Perot interference filter <NUM> are as follows. As illustrated in <FIG> (in <FIG>, the temperature control element <NUM>, the wire <NUM>, the stem <NUM>, and the like are omitted), the Fabry-Perot interference filter <NUM> is supported by a pair of support members <NUM>. The pair of support members <NUM> face each other with the light transmitting region 10a of the Fabry-Perot interference filter <NUM> interposed therebetween when seen in a direction parallel to the line L. On a bottom surface 10b of the Fabry-Perot interference filter <NUM>, a part outside the light transmitting region 10a, that is, a part along a portion of a side surface 10c of the Fabry-Perot interference filter <NUM> is placed on a placement surface 9a of each of the support members <NUM>. In this way, the support members <NUM> support parts on the bottom surface 10b of the Fabry-Perot interference filter <NUM> outside the light transmitting region 10a.

A portion of the side surface 10c of the Fabry-Perot interference filter <NUM> is positioned on the placement surface 9a of each of the support members <NUM> such that a portion of the placement surface 9a of each of the support members <NUM> is disposed outside a portion of the side surface 10c (an outer side of a portion of the side surface 10c when seen in a direction parallel to the line L). Accordingly, a corner portion C is formed by a portion of the side surface 10c and a portion of the placement surface 9a of each of the support members <NUM> (a part of a portion of the side surface 10c on an outer side, that is, a part of the placement surface 9a on which the Fabry-Perot interference filter <NUM> is not placed).

The heat conducting member <NUM> is disposed on the placement surface 9a of each of the support members <NUM> along the corner portion C. On the placement surface 9a of each of the support members <NUM>, the heat conducting member <NUM> includes a first part 15a and a second part 15b. The first part 15a is a part disposed along the corner portion C. The second part 15b is a part disposed between the placement surface 9a of the support member <NUM> and the bottom surface 10b of the Fabry-Perot interference filter <NUM>. In this way, the heat conducting member <NUM> comes into contact with each of a portion of the bottom surface 10b of the Fabry-Perot interference filter <NUM>, a portion of the side surface 10c, and a portion of the placement surface 9a of the support member <NUM>. The first part 15a leads to a side surface of a substrate <NUM> (which will be described below) of the Fabry-Perot interference filter <NUM>.

In the light detection device 1A having a configuration as described above, as illustrated in <FIG>, when light is received in the light transmitting region 10a of the Fabry-Perot interference filter <NUM> from the outside through the opening 2a of the package <NUM>, the light transmitting member <NUM>, and the band-pass filter <NUM>, light having a predetermined wavelength is selectively transmitted (details will be described below). Light which has been transmitted through the light transmitting region 10a of the Fabry-Perot interference filter <NUM> is received by the light receiving portion of the light detector <NUM> and is detected by the light detector <NUM>.

As illustrated in <FIG>, in the Fabry-Perot interference filter <NUM>, the light transmitting region 10a transmitting light corresponding to a distance between the first mirror and a second mirror is provided on the line L. In the light transmitting region 10a, the distance between the first mirror and the second mirror is controlled in an extremely accurate manner. In other words, the light transmitting region 10a is a region in the Fabry-Perot interference filter <NUM> in which the distance between the first mirror and the second mirror can be controlled to a predetermined distance in order to selectively transmit light having a predetermined wavelength, that is, a region in which light having a predetermined wavelength corresponding to the distance between the first mirror and the second mirror can be transmitted.

As illustrated in <FIG>, the Fabry-Perot interference filter <NUM> includes the substrate <NUM>. An antireflection layer <NUM>, a first laminate <NUM>, an intermediate layer <NUM>, and a second laminate <NUM> are laminated on a surface 21a of the substrate <NUM> on a light receiving side in this order. A gap (air-gap) S is formed by the frame-shaped intermediate layer <NUM> between the first laminate <NUM> and the second laminate <NUM>. For example, the substrate <NUM> is formed of silicon, quartz, and glass. When the substrate <NUM> is formed of silicon, the antireflection layer <NUM> and the intermediate layer <NUM> are formed of silicon oxide, for example. It is preferable that the thickness of the intermediate layer <NUM> be an integer multiple of <NUM>/<NUM> of a center transmission wavelength (that is, the center wavelength of a wavelength range which the Fabry-Perot interference filter <NUM> can transmit).

A part of the first laminate <NUM> corresponding to the light transmitting region 10a functions as a first mirror <NUM>. The first mirror <NUM> is supported by the substrate <NUM> with the antireflection layer <NUM> interposed therebetween. The first laminate <NUM> has a configuration in which a plurality of polysilicon layers and a plurality of silicon nitride layers are alternately laminated one by one. It is preferable that the optical thickness of each of the polysilicon layers and the silicon nitride layers constituting the first mirror <NUM> be an integer multiple of <NUM>/<NUM> of the center transmission wavelength. Silicon oxide layers may be used instead of the silicon nitride layers.

A part of the second laminate <NUM> corresponding to the light transmitting region 10a functions as a second mirror <NUM> facing the first mirror <NUM> with the gap S interposed therebetween. The second mirror <NUM> is supported by the substrate <NUM> with the antireflection layer <NUM>, the first laminate <NUM>, and the intermediate layer <NUM> interposed therebetween. The second laminate <NUM> has a configuration in which a plurality of polysilicon layers and a plurality of silicon nitride layers are alternately laminated one by one. It is preferable that the optical thickness of each of the polysilicon layers and the silicon nitride layers constituting the second mirror <NUM> be an integer multiple of <NUM>/<NUM> of the center transmission wavelength. Silicon oxide layers may be used instead of the silicon nitride layers.

A plurality of penetration holes (not illustrated) leading from a surface 34a of the second laminate <NUM> to the gap S are provided in a part in the second laminate <NUM> corresponding to the gap S. The plurality of penetration holes are formed to the extent that the function of the second mirror <NUM> is not substantially affected. The plurality of penetration holes are used for forming the gap S by removing a portion of the intermediate layer <NUM> through etching.

A first electrode <NUM> is formed in the first mirror <NUM> such that the light transmitting region 10a is surrounded. A second electrode <NUM> is formed in the first mirror <NUM> in a manner of including the light transmitting region 10a. The first electrode <NUM> and the second electrode <NUM> are formed by doping impurities in the polysilicon layers to reduce resistance. It is preferable that the size of the second electrode <NUM> be a size including the entirety of the light transmitting region 10a. However, the size may be approximately the same as the size of the light transmitting region 10a.

A third electrode <NUM> is formed in the second mirror <NUM>. The third electrode <NUM> faces the first electrode <NUM> and the second electrode <NUM> with the gap S interposed therebetween in a direction parallel to the line L. The third electrode <NUM> is formed by doping impurities in the polysilicon layers to reduce resistance.

In the Fabry-Perot interference filter <NUM>, the second electrode <NUM> is positioned on a side opposite to the third electrode <NUM> with respect to the first electrode <NUM> in a direction parallel to the line L. That is, the first electrode <NUM> and the second electrode <NUM> are not positioned on the same plane in the first mirror <NUM>. The second electrode <NUM> is farther away from the third electrode <NUM> than the first electrode <NUM>.

A pair of terminals <NUM> are provided to face each other with the light transmitting region 10a interposed therebetween. Each of the terminals <NUM> is disposed inside the penetration hole leading from the surface 34a of the second laminate <NUM> to the first laminate <NUM>. Each of the terminals <NUM> is electrically connected to the first electrode <NUM> via a wiring 22a.

A pair of terminals <NUM> are provided to face each other with the light transmitting region 10a interposed therebetween. Each of the terminals <NUM> is disposed inside the penetration hole leading from the surface 34a of the second laminate <NUM> to a location in front of the intermediate layer <NUM>. Each of the terminals <NUM> is electrically connected to the second electrode <NUM> via a wiring 23a and is electrically connected to the third electrode <NUM> via a wiring 24a. The direction in which the pair of terminals <NUM> face each other is orthogonal to the direction in which the pair of terminals <NUM> face each other (refer to <FIG>).

Trenches <NUM> and <NUM> are provided on a surface 32a of the first laminate <NUM>. The trench <NUM> annularly extends to surround the wiring 23a extending from the terminal <NUM> along a direction parallel to the line L. The trench <NUM> electrically insulates the first electrode <NUM> and the wiring 23a from each other. The trench <NUM> annularly extends along an inner edge of the first electrode <NUM>. The trench <NUM> electrically insulates the first electrode <NUM> and a region inside the first electrode <NUM> from each other. The region inside each of the trenches <NUM> and <NUM> may be an insulating material or a gap.

A trench <NUM> is provided on the surface 34a of the second laminate <NUM>. The trench <NUM> annularly extends such that the terminal <NUM> is surrounded. The trench <NUM> electrically insulates the terminal <NUM> and the third electrode <NUM> from each other. The region inside the trench <NUM> may be an insulating material or a gap.

An antireflection layer <NUM>, a third laminate <NUM>, an intermediate layer <NUM>, and a fourth laminate <NUM> are laminated on a surface 21b of the substrate <NUM> on a light emitting side in this order. The antireflection layer <NUM> and the intermediate layer <NUM> have configurations similar to those of the antireflection layer <NUM> and the intermediate layer <NUM> respectively. The third laminate <NUM> and the fourth laminate <NUM> have lamination structures respectively symmetrical to the first laminate <NUM> and the second laminate <NUM> with respect to the substrate <NUM>. The antireflection layer <NUM>, the third laminate <NUM>, the intermediate layer <NUM>, and the fourth laminate <NUM> have a function of restraining the substrate <NUM> from warping.

An opening 40a is provided in the antireflection layer <NUM>, the third laminate <NUM>, the intermediate layer <NUM>, and the fourth laminate <NUM> in a manner of including the light transmitting region 10a. The opening 40a has a diameter substantially the same as the size of the light transmitting region 10a. The opening 40a is open on the light emitting side, and a bottom surface of the opening 40a leads to the antireflection layer <NUM>. A light shielding layer <NUM> is formed on a surface of the fourth laminate <NUM> on the light emitting side. The light shielding layer <NUM> is formed of aluminum, for example. A protective layer <NUM> is formed on a surface of the light shielding layer <NUM> and an inner surface of the opening 40a. The protective layer <NUM> is formed of aluminum oxide, for example. An optical influence of the protective layer <NUM> can be disregarded by causing the thickness of the protective layer <NUM> to range from <NUM> to <NUM> (preferably, <NUM> approximately).

In the Fabry-Perot interference filter <NUM> having a configuration as described above, when a voltage is applied to a part between the first electrode <NUM> and the third electrode <NUM> via the terminals <NUM> and <NUM>, an electrostatic force corresponding to the voltage is generated between the first electrode <NUM> and the third electrode <NUM>. Due to the electrostatic force, the second mirror <NUM> is attracted to the side of the first mirror <NUM> fixed to the substrate <NUM>, so that the distance between the first mirror <NUM> and the second mirror <NUM> is adjusted. In this way, in the Fabry-Perot interference filter <NUM>, the distance between the first mirror <NUM> and the second mirror <NUM> is variable.

A wavelength of light transmitted through the Fabry-Perot interference filter <NUM> depends on the distance between the first mirror <NUM> and the second mirror <NUM> in the light transmitting region 10a. Therefore, the wavelength of light to be transmitted can be suitably selected by adjusting a voltage applied to a part between the first electrode <NUM> and the third electrode <NUM>. At this time, the second electrode <NUM> has a potential equal to that of the third electrode <NUM>. Therefore, the second electrode <NUM> functions as a compensation electrode for keeping the first mirror <NUM> and the second mirror <NUM> flat in the light transmitting region 10a.

In the light detection device 1A, while changing a voltage applied to the Fabry-Perot interference filter <NUM> (that is, while changing the distance between the first mirror <NUM> and the second mirror <NUM> in the Fabry-Perot interference filter <NUM>), the light detector <NUM> detects light which has been transmitted through the light transmitting region 10a of the Fabry-Perot interference filter <NUM>, so that a spectroscopic spectrum can be obtained.

In the light detection device 1A, the endothermic region 50a of the temperature control element <NUM> is positioned on one side with respect to the light detector <NUM> on the line L. Accordingly, for example, compared to a case in which the endothermic region 50a of the temperature control element <NUM> is positioned on a side of the Fabry-Perot interference filter <NUM> and the light detector <NUM> with respect to the line L, the Fabry-Perot interference filter <NUM> and the light detector <NUM> are uniformly cooled. Particularly, an upper surface of the temperature control element <NUM> and a lower surface of the wiring substrate <NUM>, an upper surface of the wiring substrate <NUM> and a lower surface of the light detector <NUM>, the upper surface of the wiring substrate <NUM> and lower surfaces of the support members <NUM>, and upper surfaces of the support members <NUM> and a lower surface of the Fabry-Perot interference filter <NUM> are in surface contact with each other with a bonding agent or the like interposed therebetween. Accordingly, for example, compared to a case in which members are in point contact with each other, cooling is efficiently performed. Moreover, on the line L, the Fabry-Perot interference filter <NUM> and the light detector <NUM> are disposed between the light transmitting member <NUM> and the endothermic region 50a of the temperature control element <NUM>. Accordingly, dew condensation, which is caused by an increase in difference between the temperature of the light transmitting member <NUM> and an outside air temperature (usage environment temperature of the light detection device 1A) when the light transmitting member <NUM> is excessively cooled, is restrained from occurring in the light transmitting member <NUM>. Thus, according to the light detection device 1A, dew condensation can be restrained from occurring in the light transmitting member <NUM> receiving light in the package <NUM>, and the Fabry-Perot interference filter <NUM> and the light detector <NUM> accommodated in the package <NUM> can be maintained at a uniform temperature.

In this way, in the light detection device 1A, since the Fabry-Perot interference filter <NUM> is uniformly cooled by the temperature control element <NUM>, a constant temperature in the Fabry-Perot interference filter <NUM> can be maintained independently of the usage environment temperature of the light detection device 1A. As a result, shifting of a wavelength of transmitted light caused by a change in usage environment temperature of the light detection device 1A can be restrained. Particularly, in the Fabry-Perot interference filter <NUM> having the first mirror <NUM> and the second mirror <NUM> with a variable distance therebetween, the distance between the first mirror <NUM> and the second mirror <NUM> is required to be controlled in an extremely accurate manner by operating the thin film-shaped second mirror <NUM> in an extremely accurate manner. Here, when the temperatures of parts are not uniform in the Fabry-Perot interference filter <NUM>, it becomes difficult to control the distance between the first mirror <NUM> and the second mirror <NUM> in an extremely accurate manner. Therefore, it is very important to maintain the Fabry-Perot interference filter <NUM> at a uniform temperature. Moreover, since the light detector <NUM> is uniformly cooled by the temperature control element <NUM>, a dark current generated in the light detector <NUM> can be reduced.

In a configuration in which the temperature control element <NUM> is disposed inside the package <NUM>, compared to a configuration in which the temperature control element <NUM> is disposed outside the package <NUM>, the capacity inside the package <NUM> is easily increased. Therefore, in the configuration in which the temperature control element <NUM> is disposed inside the package <NUM>, when the capacity inside the package <NUM> increases, it becomes more difficult to maintain a uniform temperature inside the package <NUM>. However, according to the configuration of the light detection device 1A, the Fabry-Perot interference filter <NUM> and the light detector <NUM> which significantly affect the accuracy of a measurement result can be effectively maintained at a uniform temperature.

Here, a risk caused by dew condensation occurring in the light transmitting member <NUM> will be described. First, when dew condensation occurs on the light receiving surface 13a and/or the light emitting surface 13b of the light transmitting member <NUM>, there is concern that the quantity of light received in the package <NUM> may decrease and the sensitivity of the light detector <NUM> may deteriorate. Moreover, in regard to light received in the package <NUM>, there is concern that multiple reflection, scattering, a lens effect, or the like may occur and cause stray light, so that resolution of transmitted light received in the light detector <NUM>, an S/N ratio, or the like may deteriorate. In this way, there is concern that when dew condensation occurs on the light receiving surface 13a and/or the light emitting surface 13b of the light transmitting member <NUM>, stability of detection properties in the light detector <NUM> may deteriorate.

In addition, there is concern that when dew condensation occurs on the second mirror <NUM> of the Fabry-Perot interference filter <NUM>, a peak wavelength of transmitted light with respect to a control voltage applied to the Fabry-Perot interference filter <NUM> may change. Moreover, there is concern that the first mirror <NUM> and the second mirror <NUM> may adhere to each other due to moisture, which may lead to a malfunction.

In contrast, in the light detection device 1A, since dew condensation can be restrained from occurring in the light transmitting member <NUM>, it is possible to avoid the above-described risk. Particularly, when moisture remains inside the package <NUM> in a production process, the configuration of the light detection device 1A in which dew condensation can be restrained from occurring in the light transmitting member <NUM> is effective. Moreover, since the configuration of the light detection device 1A is a configuration in which dew condensation can be restrained from occurring in the light transmitting member <NUM>, the light detection device 1A can be reduced in size by narrowing the distance between the members.

In the light detection device 1A, when seen in a direction parallel to the line L, the outer edge of the opening 2a of the package <NUM> is positioned inside the outer edge of the Fabry-Perot interference filter <NUM>, and the exothermic region 50b of the temperature control element <NUM> is thermally connected to the package <NUM>. Accordingly, for example, compared to a case in which the outer edge of the opening 2a is positioned outside the outer edge of the Fabry-Perot interference filter <NUM>, heat is easily transferred between the exothermic region 50b of the temperature control element <NUM> and the light transmitting member <NUM> through the package <NUM> (specifically, heat is easily transferred from the exothermic region 50b of the temperature control element <NUM> to the light transmitting member <NUM> through the package <NUM>). Thus, dew condensation can be more reliably restrained from occurring in the light transmitting member <NUM>.

In the light detection device 1A, when seen in a direction parallel to the line L, the outer edge of the light transmitting member <NUM> is positioned outside the outer edge of the Fabry-Perot interference filter <NUM>. Accordingly, for example, compared to a case in which the outer edge of the light transmitting member <NUM> is positioned inside the outer edge of the Fabry-Perot interference filter <NUM>, a contact area between the light transmitting member <NUM> and the package <NUM> increases, so that heat is easily transferred between the light transmitting member <NUM> and the package <NUM> (specifically, heat is easily transferred from the exothermic region 50b of the temperature control element <NUM> to the light transmitting member <NUM> through the package <NUM>). Moreover, in the light detection device 1A, since the side surface 13c of the light transmitting member <NUM> comes into contact with the package <NUM>, the contact area between the light transmitting member <NUM> and the package <NUM> further increases. Thus, dew condensation can be more reliably restrained from occurring in the light transmitting member <NUM>. Moreover, according to this configuration, even if the wire <NUM> connected to the Fabry-Perot interference filter <NUM> is bent, the insulative light transmitting member <NUM> prevents the wire <NUM> and the package <NUM> from coming into contact with each other. Accordingly, an electrical signal for controlling the Fabry-Perot interference filter <NUM> is prevented from flowing in the package <NUM>, so that the Fabry-Perot interference filter <NUM> can be controlled with high accuracy.

In the light detection device 1A, the temperature control element <NUM> is disposed inside the package <NUM>, the light detector <NUM> is disposed on the temperature control element <NUM>, and the Fabry-Perot interference filter <NUM> is disposed on the temperature control element <NUM> such that the light detector <NUM> is positioned between the temperature control element <NUM> and the Fabry-Perot interference filter <NUM>. Accordingly, the Fabry-Perot interference filter <NUM> and the light detector <NUM> can be efficiently maintained at a uniform temperature with a compact and simple configuration.

As an example, in a direction parallel to the line L, the thickness of the temperature control element <NUM> ranges from <NUM> to <NUM>, the thickness of the wiring substrate <NUM> is <NUM>, the thickness of the support member <NUM> is <NUM>, and the thickness of the Fabry-Perot interference filter <NUM> is <NUM>. In addition, the height of a part of the lead pin <NUM> protruding from an upper surface of the stem <NUM> ranges from <NUM> to <NUM> (for example, <NUM>). That is, the temperature control element <NUM> is thicker than the wiring substrate <NUM>, the support members <NUM>, and the Fabry-Perot interference filter <NUM>. Since the temperature control element <NUM> is thick, the light detector <NUM> and the Fabry-Perot interference filter <NUM> are unlikely to be affected by heat generated from the exothermic region 50b. On the other hand, since the wiring substrate <NUM>, the support members <NUM>, and the Fabry-Perot interference filter <NUM> are thin, cooling can be efficiently performed by the endothermic region 50a.

In addition, in the light detection device 1A, the upper surface of the lead pin <NUM> is at a position lower than the upper surface of each of the temperature control element <NUM>, the wiring substrate <NUM>, the support members <NUM>, and the Fabry-Perot interference filter <NUM>. Accordingly, the wire <NUM> is easily connected to the lead pin <NUM> from the light detector <NUM> and the Fabry-Perot interference filter <NUM> (particularly, the wire <NUM>, which is drawn out from the light detector <NUM> or the temperature compensating element disposed to be covered by the Fabry-Perot interference filter <NUM> from above, can be restrained from interfering with the Fabry-Perot interference filter <NUM>).

In consideration of easiness of connecting the wire <NUM> to the lead pin <NUM> from the Fabry-Perot interference filter <NUM>, it is preferable that the height of the Fabry-Perot interference filter <NUM> from the stem <NUM> be not excessively significant. Accordingly, since the height of the Fabry-Perot interference filter <NUM> from the stem <NUM> becomes excessive in a configuration in which the temperature control element <NUM> is disposed under a lamination of the wiring substrate <NUM>, the support member <NUM>, and the Fabry-Perot interference filter <NUM>, which is not preferable from the viewpoint of connecting a wire to the lead pin <NUM>. However, in the light detection device 1A, the height of the Fabry-Perot interference filter <NUM> from the stem <NUM> is restrained by restricting the thicknesses of the wiring substrate <NUM>, the support member <NUM>, and the Fabry-Perot interference filter <NUM>, and the disadvantage is thereby minimized.

In the light detection device 1A, the Fabry-Perot interference filter <NUM> and the light transmitting member <NUM> are separated from each other with a gap interposed therebetween. Accordingly, the Fabry-Perot interference filter <NUM> can be restrained from being affected by the usage environment temperature of the light detection device 1A and being affected by heat from the package <NUM> and the light transmitting member <NUM>. Particularly, in the light detection device 1A, the volume of a space on an upper side of the Fabry-Perot interference filter <NUM> (a space between the upper surface of the Fabry-Perot interference filter <NUM> and the light emitting surface 13b of the light transmitting member <NUM>) is greater than the volume of a space on a lower side of the Fabry-Perot interference filter <NUM> (a space between the lower surface of the Fabry-Perot interference filter <NUM> and the upper surface of the wiring substrate <NUM>). Therefore, heat transfer between the Fabry-Perot interference filter <NUM> and the light transmitting member <NUM> is effectively restrained.

In the light detection device 1A, the support members <NUM> which support parts on the bottom surface 10b of the Fabry-Perot interference filter <NUM> outside the light transmitting region 10a, the side surface 10c of the Fabry-Perot interference filter <NUM>, and the heat conducting member <NUM> which comes into contact with the support members <NUM> are provided. Accordingly, for example, compared to a case in which the side surface 10c of the Fabry-Perot interference filter <NUM>, and the heat conducting member <NUM> coming into contact with the support members <NUM> are not provided, heat is easily transferred between the Fabry-Perot interference filter <NUM> and the endothermic region 50a of the temperature control element <NUM> with the support members <NUM> interposed therebetween (specifically, heat is easily transferred from the Fabry-Perot interference filter <NUM> to the endothermic region 50a of the temperature control element <NUM> with the support members <NUM> interposed therebetween). Thus, the Fabry-Perot interference filter <NUM> and the light detector <NUM> can be efficiently maintained at a uniform temperature.

In the light detection device 1A, the heat conducting member <NUM> is a bonding member bonding the Fabry-Perot interference filter <NUM> and the support members <NUM>. Accordingly, a held state of the Fabry-Perot interference filter <NUM> on the support members <NUM> can be stabilized.

In the light detection device 1A, the heat conducting member <NUM> is disposed in the corner portion C and comes into contact with each of a portion of the side surface 10c of the Fabry-Perot interference filter <NUM> and a portion of the placement surface 9a of the support member <NUM>. Accordingly, the Fabry-Perot interference filter <NUM> and the light detector <NUM> can be more efficiently maintained at a uniform temperature, and the held state of the Fabry-Perot interference filter <NUM> on the support members <NUM> can be more reliably stabilized. Particularly, when the heat conducting member <NUM> is disposed in the corner portion C, the heat conducting member <NUM> can be increased in volume, and the posture of the heat conducting member <NUM> can be stabilized, thereby being effective.

As illustrated in <FIG>, a light detection device 1B differs from the above-described light detection device 1A in that the light detection device 1B is configured as a surface mount device (SMD). The light detection device 1B includes a main body portion <NUM> constituting the package <NUM> which accommodates the light detector <NUM> and the Fabry-Perot interference filter <NUM>. As a material of the main body portion <NUM>, for example, ceramic and resin can be used. A plurality of wirings (not illustrated) are laid in the main body portion <NUM>. A plurality of mounting electrode pads <NUM> are provided on a bottom surface 200a of the main body portion <NUM>. The wirings (not illustrated) and the mounting electrode pads <NUM> corresponding to each other are electrically connected to each other.

A first widened portion <NUM>, a second widened portion <NUM>, a third widened portion <NUM>, a fourth widened portion <NUM>, and a recessed portion <NUM> are formed in the main body portion <NUM>. The recessed portion <NUM>, the fourth widened portion <NUM>, the third widened portion <NUM>, the second widened portion <NUM>, and the first widened portion <NUM> are arranged side by side from the bottom surface 200a side in this order with the predetermined line L (straight line) as the center line and form one space which is open to a side opposite to the bottom surface.

The light detector <NUM> is fixed to a bottom surface of the recessed portion <NUM>. The bottom surface of the recessed portion <NUM> and the bottom surface of the light detector <NUM> are bonded to each other, for example, with a heat conductive bonding member (not illustrated) interposed therebetween. The light detector <NUM> is disposed on the line L. More specifically, the light detector <NUM> is disposed such that the center line of its light receiving portion coincides with the line L. The Fabry-Perot interference filter <NUM> is fixed to the bottom surface of the third widened portion <NUM> with the heat conducting member <NUM> interposed therebetween. That is, the bottom surface of the third widened portion <NUM> and the bottom surface 10b of the Fabry-Perot interference filter <NUM> are bonded to each other with the heat conducting member <NUM> interposed therebetween. The Fabry-Perot interference filter <NUM> is disposed on the line L. More specifically, the Fabry-Perot interference filter <NUM> is disposed such that the center line of its light transmitting region 10a coincides with the line L. The plate-shaped light transmitting member <NUM> is fixed to the bottom surface of the first widened portion <NUM>, for example, with a heat conductive bonding member. The band-pass filter <NUM> is provided on the light emitting surface 13b of the light transmitting member <NUM>. A temperature compensating element (not illustrated) is embedded in the main body portion <NUM>.

Each of the terminal of the light detector <NUM>, the terminal of the temperature compensating element, and the terminal of the Fabry-Perot interference filter <NUM> is electrically connected to the corresponding mounting electrode pad <NUM> via the wire <NUM> and a wiring (not illustrated) interposed therebetween, or via only a wiring (not illustrated). Accordingly, an electrical signal can be input and output with respect to each of the light detector <NUM>, the temperature compensating element, and the Fabry-Perot interference filter <NUM>.

Moreover, the temperature control element <NUM> is embedded in a predetermined part of the main body portion <NUM> which is a wall portion of the package <NUM>. More specifically, the temperature control element <NUM> is embedded in the main body portion <NUM> throughout the entirety of a part between the bottom surface of the recessed portion <NUM> and the bottom surface 200a of the main body portion <NUM>, a part between the bottom surface of the fourth widened portion <NUM> and the bottom surface 200a of the main body portion <NUM>, and a part between the bottom surface of the third widened portion <NUM> and the bottom surface 200a of the main body portion <NUM>.

For example, the temperature control element <NUM> is a Peltier element. In the temperature control element <NUM>, a plurality of N-type semiconductor layers <NUM> and a plurality of P-type semiconductor layers <NUM> are alternately arranged side by side. End portions of the N-type semiconductor layer <NUM> and the P-type semiconductor layer <NUM> adjacent to each other on a side opposite to the bottom surface 200a are connected to each other with a first metal member <NUM> interposed therebetween, and end portions of the N-type semiconductor layer <NUM> and the P-type semiconductor layer <NUM> adjacent to each other on the bottom surface 200a side are connected to each other with a second metal member <NUM> interposed therebetween, such that all of the N-type semiconductor layers <NUM> and the P-type semiconductor layers <NUM> alternately arranged side by side are connected in series.

Focusing on the N-type semiconductor layer <NUM> and the P-type semiconductor layer <NUM> connected to each other by the first metal member <NUM>, when a current flows in a direction from the N-type semiconductor layer <NUM> to the P-type semiconductor layer <NUM>, an endothermic phenomenon occurs in the first metal member <NUM>. Accordingly, the bottom surface of the third widened portion <NUM>, the bottom surface of the fourth widened portion <NUM>, and the bottom surface of the recessed portion <NUM> function as the endothermic region 50a.

Focusing on the P-type semiconductor layer <NUM> and the N-type semiconductor layer <NUM> connected to each other by the second metal member <NUM>, when a current flow in a direction from the P-type semiconductor layer <NUM> to the N-type semiconductor layer <NUM>, an exothermic phenomenon occurs in the second metal member <NUM>. Accordingly, the bottom surface 200a of the main body portion <NUM> functions as the exothermic region 50b.

The terminal of the temperature control element <NUM> is electrically connected to the corresponding mounting electrode pad <NUM> via a wiring (not illustrated). Accordingly, an electrical signal can be input and output with respect to the temperature control element <NUM>. In the temperature control element <NUM>, all of the N-type semiconductor layers <NUM> and the P-type semiconductor layers <NUM> alternately arranged side by side are connected in series. Therefore, when a current flows in a predetermined direction, a current flows in a direction from the N-type semiconductor layer <NUM> to the P-type semiconductor layer <NUM> in the first metal member <NUM>, and the bottom surface of the third widened portion <NUM>, the bottom surface of the fourth widened portion <NUM>, and the bottom surface of the recessed portion <NUM> function as the endothermic region 50a. On the other hand, a current flows in a direction from the P-type semiconductor layer <NUM> to the N-type semiconductor layer <NUM> in the second metal member <NUM>, and the bottom surface 200a of the main body portion <NUM> functions as the exothermic region 50b.

In the light detection device 1B, the package <NUM> accommodates the light detector <NUM>, the heat conducting member <NUM>, and the Fabry-Perot interference filter <NUM>. The temperature compensating element (not illustrated) and the temperature control element <NUM> are embedded in the wall portion of the package <NUM>. The light detector <NUM> is disposed on the bottom surface of the recessed portion <NUM> which is the endothermic region 50a of the temperature control element <NUM>. The bottom surface of the recessed portion <NUM> (endothermic region 50a) is thermally connected to the light detector <NUM>. The Fabry-Perot interference filter <NUM> is disposed on the bottom surface of the third widened portion <NUM> which is the endothermic region 50a of the temperature control element <NUM> with the heat conducting member <NUM> interposed therebetween such that the light detector <NUM> is positioned between the temperature control element <NUM> and the Fabry-Perot interference filter <NUM>. The bottom surface of the third widened portion <NUM> (endothermic region 50a) is thermally connected to the Fabry-Perot interference filter <NUM>.

A heat sink <NUM> is bonded to the bottom surface 200a of the main body portion <NUM> which is the exothermic region 50b of the temperature control element <NUM> with a heat conductive bonding member interposed therebetween, for example. Accordingly, heat generated from the exothermic region 50b can be efficiently radiated through the heat sink <NUM>. When the heat sink <NUM> is thicker than the electrode pad <NUM>, the light detection device 1B can be mounted on an external wiring substrate by providing a penetration hole such that the heat sink <NUM> does not interfere with the external wiring substrate on which the light detection device 1B is mounted. Alternatively, without providing a penetration hole in the external wiring substrate, the electrode pad <NUM> may be disposed on the side surface of the main body portion <NUM>, and the light detection device 1B may be mounted such that the line L becomes substantially horizontal with the surface of the external wiring substrate. Alternatively, a metal plate thinner than the electrode pad <NUM> may be bonded to the bottom surface 200a of the main body portion <NUM> to be used as the heat sink <NUM>. In this case, if the metal plate is formed of the same material (for example, gold, silver, copper, aluminum, and tungsten) as that of the electrode pad <NUM>, forming steps with respect to the bottom surface 200a can be performed at the same time.

The light detector <NUM> is positioned on one side with respect to the Fabry-Perot interference filter <NUM> on the line L (here, the bottom surface 200a side of the main body portion <NUM>), and the bottom surface of the recessed portion <NUM> which is the endothermic region 50a of the temperature control element <NUM> is positioned on one side with respect to the light detector <NUM> on the line L (here, the bottom surface 200a side of the main body portion <NUM>). The opening (first widened portion <NUM>) of the package <NUM> and the light transmitting member <NUM> are positioned on the other side with respect to the Fabry-Perot interference filter <NUM> on the line L (side opposite to the one side) (here, a side opposite to the bottom surface 200a of the main body portion <NUM>). The Fabry-Perot interference filter <NUM> and the light transmitting member <NUM> are separated from each other with a gap interposed therebetween.

In the light detection device 1B, the heat conducting member <NUM> is disposed on the bottom surface of the third widened portion <NUM> along a clearance between the side surface of the Fabry-Perot interference filter <NUM> and an inner surface of the third widened portion <NUM>. The heat conducting member <NUM> includes a first part which is disposed along the clearance between the side surface of the Fabry-Perot interference filter <NUM> and the inner surface of the third widened portion <NUM>, and a second part which is disposed between the bottom surface of the third widened portion <NUM> and the bottom surface of the Fabry-Perot interference filter <NUM>. In this way, the heat conducting member <NUM> comes into contact with each of a portion of the bottom surface of the Fabry-Perot interference filter <NUM>, a portion of the side surface, and the bottom surface of the third widened portion <NUM>. The above-described first part leads to the side surface of the substrate <NUM> of the Fabry-Perot interference filter <NUM>.

In the light detection device 1B having a configuration as described above, when light is received in the light transmitting region 10a of the Fabry-Perot interference filter <NUM> from the outside with the opening (first widened portion <NUM>) of the package <NUM>, the light transmitting member <NUM>, and the band-pass filter <NUM> interposed therebetween, light having a predetermined wavelength is selectively transmitted in accordance with the distance between the first mirror <NUM> and the second mirror <NUM> in the light transmitting region 10a. Light which has been transmitted through the light transmitting region 10a of the Fabry-Perot interference filter <NUM> is received by the light receiving portion of the light detector <NUM> and is detected by the light detector <NUM>. In the light detection device 1B, while changing a voltage applied to the Fabry-Perot interference filter <NUM> (that is, while changing the distance between the first mirror <NUM> and the second mirror <NUM> in the Fabry-Perot interference filter <NUM>), the light detector <NUM> detects light which has been transmitted through the light transmitting region 10a of the Fabry-Perot interference filter <NUM>, so that a spectroscopic spectrum can be obtained.

In the light detection device 1B, the bottom surface of the recessed portion <NUM> in the endothermic region 50a of the temperature control element <NUM> is positioned on one side with respect to the light detector <NUM> on the line L. Moreover, the bottom surface of the third widened portion <NUM> in the endothermic region 50a of the temperature control element <NUM> is positioned on one side with respect to the Fabry-Perot interference filter <NUM>. Accordingly, the Fabry-Perot interference filter <NUM> and the light detector <NUM> are uniformly cooled. Particularly, the bottom surface of the recessed portion <NUM> and the lower surface of the light detector <NUM>, and the bottom surface of the third widened portion <NUM> and the lower surface of the Fabry-Perot interference filter <NUM> are in surface contact with each other with a bonding agent or the like interposed therebetween. Accordingly, for example, compared to a case in which members are in point contact with each other, cooling is efficiently performed. Moreover, on the line L, the Fabry-Perot interference filter <NUM> and the light detector <NUM> are disposed between the light transmitting member <NUM> and the bottom surface of the recessed portion <NUM>. Moreover, the Fabry-Perot interference filter <NUM> is disposed between the light transmitting member <NUM> and the bottom surface of the third widened portion <NUM>. Accordingly, dew condensation, which is caused by an increase in difference between the temperature of the light transmitting member <NUM> and an outside air temperature (usage environment temperature of the light detection device 1B) when the light transmitting member <NUM> is excessively cooled, is restrained from occurring in the light transmitting member <NUM>. Thus, according to the light detection device 1B dew condensation can be restrained from occurring in the light transmitting member <NUM> receiving light in the package <NUM>, and the Fabry-Perot interference filter <NUM> and the light detector <NUM> accommodated in the package <NUM> can be maintained at a uniform temperature.

In the light detection device 1B, the heat conducting member <NUM> is a bonding member bonding the Fabry-Perot interference filter <NUM> and the main body portion <NUM>. Accordingly, the held state of the Fabry-Perot interference filter <NUM> in the third widened portion <NUM> of the main body portion <NUM> can be stabilized.

In the light detection device 1B, the heat conducting member <NUM> is disposed on the bottom surface of the third widened portion <NUM> along the clearance between the side surface of the Fabry-Perot interference filter <NUM> and the inner surface of the third widened portion <NUM> and comes into contact with each of a portion of the side surface of the Fabry-Perot interference filter <NUM> and the bottom surface of the third widened portion <NUM>. Accordingly, the Fabry-Perot interference filter <NUM> and the light detector <NUM> can be more efficiently maintained at a uniform temperature, and the held state of the Fabry-Perot interference filter <NUM> in the third widened portion <NUM> of the main body portion <NUM> can be more reliably stabilized.

In the light detection device 1B, the temperature control element <NUM> is embedded in the wall portion of the package <NUM>. Accordingly, the volume of a space inside the package <NUM> can be reduced. As a result, the Fabry-Perot interference filter <NUM> and the light detector <NUM> can be more efficiently maintained at a uniform temperature.

Hereinabove, the first embodiment which does not fall under the scope of the claims and the second embodiment, which is an embodiment of the claimed invention, have been described. However, the light detection device of the present disclosure is not limited to the first embodiment and the second embodiment described above. For example, the material and the shape of each configuration are not limited to the material and the shape described above, and various materials and shapes can be employed.

In addition, as illustrated in <FIG>, as a modification example of the light detection device 1B of the second embodiment, which is another embodiment of the claimed invention, an annular groove <NUM> surrounding the temperature control element <NUM>, the light detector <NUM>, the heat conducting member <NUM>, and the Fabry-Perot interference filter <NUM> may be formed in the main body portion <NUM>. According to this configuration, the temperature control element <NUM>, the light detector <NUM>, the heat conducting member <NUM>, and the Fabry-Perot interference filter <NUM> can be thermally separated from each other. As a result, the Fabry-Perot interference filter <NUM> and the light detector <NUM> can be more efficiently maintained at a uniform temperature.

In addition, as illustrated in <FIG>, as another modification example of the light detection device 1B of the second embodiment, which is yet another embodiment of the claimed invention, the terminal of the Fabry-Perot interference filter <NUM> and the terminal of the light detector <NUM> may be connected to a wiring (not illustrated) laid in the main body portion <NUM> by a bump <NUM>. According to this configuration, since the wire <NUM> becomes no longer necessary, the light detection device 1B can be reduced in size.

In addition, in each of the light detection device 1A of the first embodiment and the light detection device 1B of the second embodiment, the band-pass filter <NUM> may be provided on the light receiving surface 13a of the light transmitting member <NUM> or may be provided on both the light receiving surface 13a and the light emitting surface 13b of the light transmitting member <NUM>.

In addition, in each of the light detection device 1A of the first embodiment and the light detection device 1B of the second embodiment, the Fabry-Perot interference filter <NUM> does not have to include the lamination structure (the antireflection layer <NUM>, the third laminate <NUM>, the intermediate layer <NUM>, the fourth laminate <NUM>, the light shielding layer <NUM>, and the protective layer <NUM>) provided on the surface 21b of the substrate <NUM> on the light emitting side. In addition, only a part of layers (for example, only the antireflection layer <NUM> and the protective layer <NUM>) may be included as necessary.

In addition, in each of the light detection device 1A of the first embodiment and the light detection device 1B of the second embodiment, the outer edge of the light transmitting region 10a of the Fabry-Perot interference filter <NUM> may be positioned outside the outer edge of the opening 2a when seen in a direction parallel to the line L. In this case, the proportion of light entering the light transmitting region 10a to light received through the opening 2a increases, and efficiency of utilizing light received through the opening 2a is enhanced. In addition, even if the opening 2a is positionally misaligned with the light transmitting region 10a to a certain degree, light received from the opening 2a enters the light transmitting region 10a. Therefore, requirements of positional accuracy at the time of assembling the light detection devices 1A and 1B are relaxed.

In addition, in each of the light detection device 1A of the first embodiment and the light detection device 1B of the second embodiment, if the heat conducting member <NUM> includes the first part 15a, the heat conducting member <NUM> does not have include the second part 15b. The material of the heat conducting member <NUM> is not limited to the materials described above and may be metal such as solder.

In addition, in each of the light detection device 1A of the first embodiment and the light detection device 1B of the second embodiment, the endothermic region 50a of the temperature control element <NUM> may directly be in contact with the Fabry-Perot interference filter <NUM> to be thermally connected to the Fabry-Perot interference filter <NUM> or may be thermally connected to the Fabry-Perot interference filter <NUM> via a certain member. Similarly, the endothermic region 50a of the temperature control element <NUM> may directly be in contact with the light detector <NUM> to be thermally connected to the light detector <NUM> or may be thermally connected to the light detector <NUM> via a certain member.

In addition, in the light detection device 1A of the first embodiment, the exothermic region 50b of the temperature control element <NUM> may directly be in contact with the package <NUM> to be thermally connected to the package <NUM> or may be thermally connected to the package <NUM> with a certain member interposed therebetween.

In addition, in each of the light detection device 1A of the first embodiment and the light detection device 1B of the second embodiment, the light detector <NUM> may be directly disposed on the temperature control element <NUM> or may be disposed on the temperature control element <NUM> via a certain member.

In addition, in each of the light detection device 1A of the first embodiment and the light detection device 1B of the second embodiment, the temperature control element <NUM> is used for the purpose of cooling the inside of the package <NUM>. This is effective when the usage environment temperature of the light detection devices 1A and 1B is higher than a set temperature (appropriate operation temperature) of the Fabry-Perot interference filter <NUM> and the light detector <NUM>. In contrast, when the usage environment temperature of the light detection devices 1A and 1B is lower than a set temperature of the Fabry-Perot interference filter <NUM> and the light detector <NUM>, the temperature control element <NUM> may be used for the purpose of heating the inside of the package <NUM>. That is, in the temperature control element <NUM>, the region which has functioned as the endothermic region 50a (first region thermally connected to the Fabry-Perot interference filter <NUM> and the light detector <NUM>) may function as the exothermic region 50b, and the region which has functioned as the exothermic region 50b (in the light detection device 1A of the first embodiment, the second region thermally connected to the package <NUM>) may function as the endothermic region 50a. Accordingly, even when the usage environment temperature of the light detection devices 1A and 1B is low, the Fabry-Perot interference filter <NUM> and the light detector <NUM> accommodated in the package <NUM> can be maintained at a uniform temperature. Particularly, shifting of a wavelength of transmitted light caused by a change in usage environment temperature of the light detection devices 1A and 1B can be restrained. In addition, it is possible to restrain damage (occurrence of a crack caused by a stress difference between the light receiving surface 13a which contracts due to the low outside air temperature and the light emitting surface 13b which is heated and expands) of the light transmitting member <NUM> caused when the light transmitting member <NUM> is excessively heated and a difference between the temperature of the light transmitting member <NUM> and the outside air temperature (usage environment temperature of the light detection devices 1A and 1B) increases. If a Peltier element is used as the temperature control element <NUM>, the endothermic region and the exothermic region can be easily switched by switching the direction in which a current flows in the Peltier element.

Claim 1:
A light detection device (1B) comprising:
a Fabry-Perot interference filter (<NUM>) having a first mirror and a second mirror with a variable distance therebetween and provided with a light transmitting region (10a) transmitting light corresponding to the distance between the first mirror and the second mirror on a predetermined line;
a light detector (<NUM>) disposed on one side with respect to the Fabry-Perot interference filter (<NUM>) on the line and configured to detect light transmitted through the light transmitting region (10a);
a package (<NUM>) having an opening positioned on the other side with respect to the Fabry-Perot interference filter (<NUM>) on the line and configured to accommodate the Fabry-Perot interference filter (<NUM>) and the light detector (<NUM>); and
a temperature control element (<NUM>) thermally connected to the Fabry-Perot interference filter (<NUM>) and the light detector (<NUM>),
wherein the light detector (<NUM>) is disposed on a bottom surface of a recessed portion (<NUM>) formed in the package (<NUM>),
the Fabry-Perot interference filter (<NUM>) is disposed on a bottom surface of a widened portion (<NUM>) formed in the package (<NUM>) so as to be positioned on the other side with respect to the recessed portion (<NUM>), and
the temperature control element (<NUM>) is embedded in at least a part of a wall portion (<NUM>) of the package (<NUM>), the part corresponding to the bottom surface of the recessed portion (<NUM>).