JP2020016519A - Optical component - Google Patents

Abstract

To provide an optical component which prevents its glass from been broken during incorporation into an optical gas sensor, and which can sufficiently transmit infrared.SOLUTION: An optical component 1 includes: a window material 2 made of chalcogenide glass; and a support member 3 for supporting the window material. The support member is a cap member including a cylindrical side wall part which includes openings on tip and base end sides. The window material is fixed in a manner to cover the openings of the cap member.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to an optical component used for a gas sensor, a gas alarm, a gas concentration measuring device, and the like.

In recent years, attention has been paid to indoor air quality, and there is a demand for a small, inexpensive gas sensor having excellent maintainability. In response to this demand, various gas sensors using semiconductors, ceramics, and the like have been developed. For example, an optical sensor using infrared light absorption, which is excellent in both sensitivity and stability, is used for a CO ₂ sensor.

  An optical gas sensor utilizing infrared light absorption requires a member for transmitting infrared light to a sensor light receiving portion. As such a member, glass or the like is used (for example, see Patent Document 1).

JP 2005-207891 A

  However, glass has a problem in that it has low mechanical strength and is easily broken when incorporated into an optical gas sensor.

  The present invention has been made in view of such a situation, and provides an optical component that hardly breaks glass when incorporated in an optical gas sensor and can sufficiently transmit infrared light. Aim.

  The optical component of the present invention includes a window member made of chalcogenide glass and a support member that supports the window member. If the chalcogenide glass alone is incorporated into the optical gas sensor, the chalcogenide glass may be broken due to contact with another member or the like. In the present invention, since the handling is facilitated by providing the support member for supporting the chalcogenide glass, the contact between the chalcogenide glass and other members is easily prevented when the chalcogenide glass is incorporated into the optical gas sensor, and the chalcogenide glass is hardly damaged. Further, since the chalcogenide glass has excellent infrared light transmission characteristics, the sensitivity of the optical gas sensor can be improved.

  The optical component according to the aspect of the invention is a cap member in which the support member includes a cylindrical side wall having an opening on the distal end side and the proximal end side, and the window member is fixed so as to cover the opening of the cap member. Is preferred. By using the support member as a cap member, the support member can be easily fixed in the optical gas sensor.

  In the optical component of the present invention, it is preferable that the window material has a lens shape. By having a lens shape, since it has an excellent light collecting ability, the sensitivity of the optical gas sensor using infrared light absorption can be further improved. It is also possible to convert diffused light into collimated light.

  In the optical component of the present invention, it is preferable that the chalcogenide glass contains, as a composition, more than 0 to 70% of Ge + Ga + Sb + Bi + Sn + In + Ag + Si and more than 90% of S + Se + Te in mole%. Note that “Ge + Ga + Sb + Bi + Sn + In + Ag + Si” means the total amount of Ge, Ga, Sb, Bi, Sn, In, Ag, and Si, and “S + Se + Te” means the total amount of each of S, Se, and Te. Means

  In the optical component of the present invention, the chalcogenide glass preferably has a maximum transmittance of 40% or more in a wavelength range of 3 to 12 μm at a thickness of 1 mm.

In the optical component of the present invention, the chalcogenide glass preferably has a coefficient of thermal expansion of 250 × 10 ⁻⁷ / ° C. or less in a temperature range of 0 to 150 ° C. In this way, deformation due to temperature change can be suppressed.

  In the optical component of the present invention, it is preferable that an antireflection film is formed on a surface of the window material. This makes it easy to improve the light transmittance in the infrared region.

In the optical component of the present invention, the support member preferably has a thermal expansion coefficient of 250 × 10 ⁻⁷ / ° C. or less in a temperature range of 0 to 150 ° C. In this way, deformation due to temperature change can be suppressed.

The optical component of the present invention is preferably used for optical sensor applications.

  According to the present invention, it is possible to provide an optical component in which glass is not easily broken when incorporated into an optical gas sensor and is capable of sufficiently transmitting infrared light.

FIG. 2 is a schematic plan view illustrating the optical component according to the first embodiment of the present invention. It is a typical sectional view showing AA section of an optical component concerning a 1st embodiment of the present invention. FIG. 9 is a schematic plan view illustrating an optical component according to a second embodiment of the present invention. It is a typical sectional view showing BB section of an optical component concerning a 2nd embodiment of the present invention. FIG. 13 is a schematic plan view illustrating an optical component according to a third embodiment of the present invention. It is a typical sectional view showing CC section of an optical component concerning a 3rd embodiment of the present invention. FIG. 13 is a schematic plan view illustrating an optical component according to a fourth embodiment of the present invention. It is a typical sectional view showing DD section of an optical component concerning a 4th embodiment of the present invention.

  Hereinafter, embodiments of the optical component of the present invention will be described.

(1) First Embodiment FIG. 1A is a schematic plan view showing an optical component (optical cap component) according to a first embodiment of the present invention, and FIG. 1B is a plan view of the first embodiment of the present invention. It is a typical sectional view showing the AA section of such an optical component.

  In the present embodiment, the optical component 1 includes a window 2 made of chalcogenide glass and a support member 3 that supports the window 2. As described above, the provision of the support member 3 makes it difficult for the window member 2 made of chalcogenide glass to be damaged when the optical component 1 is incorporated into the optical gas sensor.

  The support member 3 is a cap member having a side wall 3c having an opening 3a on the distal end side and an opening 3b on the proximal end side. The side wall 3c has a cylindrical shape having substantially the same inner diameter over the entire length. The window member 2 is fixed so as to cover the opening 3a on the distal side of the support member 3 or between the opening 3a on the distal side and the opening 3b on the proximal side.

  As a method of fixing the window material 2 to the support member 3, a method of applying a bonding material such as a low-melting glass, an adhesive, and solder between the window material 2 and the support member 3 can be used. Alternatively, the window material 2 itself may be melted and fused to the support member 3. Alternatively, when the thermal expansion coefficient of the support member 3 is higher than the thermal expansion coefficient of the window material 2, the window material 2 is housed in the support member 3, and then heated and cooled, so that the heat of the support member 3 and the window material 2 is increased. The window member 2 can be fixed by the support member 3 and fixed by the difference in shrinkage ratio.

  Hereinafter, each component will be described.

(Window material 2)
The window material 2 is made of chalcogenide glass. Chalcogenide glass has good light transmittance in the infrared region.

  The chalcogenide glass preferably contains, as a composition, more than 70% of Ge + Ga + Sb + Bi + Sn + In + Ag + Si 0% to more than 90% and more than 90% of S + Se + Te 0%. The reason for limiting the glass composition range in this way will be described below. In the following description of the content of each component, “%” indicates “mol%” unless otherwise specified.

  Ge, Ga, Sb, Bi, Sn, In, Ag, and Si are components that extend the vitrification range, and the total content of these components is preferably more than 0 to 70%, and 1 to 60%. More preferably, it is still more preferably 10 to 50%. When Ge, Ga, Sb, Bi, Sn, In, Ag, and Si are not contained, it is difficult to vitrify. On the other hand, when these contents are too large, it becomes difficult to vitrify. The contents of Ge, Ga, Sb, Bi, Sn, In, Ag, and Si are each preferably 0 to 70%, and more preferably 0 to 50%.

  S, Se, and Te, which are chalcogen elements, are components that form a glass skeleton. The content of S + Se + Te (the total amount of S, Se, and Te) is preferably more than 0 to 90%, more preferably 10 to 85%, and even more preferably 20 to 80%. When S, Se, and Te are not contained, it is difficult to vitrify. On the other hand, if the total amount of S, Se and Te is too large, the weather resistance may be reduced.

  As the chalcogen element, it is preferable to select S or Te from the viewpoint of environment.

  It is preferable that the chalcogenide glass does not substantially contain toxic substances As, Cd, Tl and Pb. In this way, the impact on the environment can be minimized. Here, “substantially not contained” means that it is not intentionally contained in the raw material, and does not exclude inclusion of an impurity level. Objectively, the content of each component is less than 1000 ppm.

  Glass having the above composition tends to have a maximum transmittance of 40% or more, 45% or more, particularly 50% or more in a wavelength range of 3 to 12 μm at a thickness of 1 mm.

Further, the coefficient of thermal expansion of the chalcogenide glass is 250 × 10 ⁻⁷ / ° C. or less, 220 × 10 ⁻⁷ / ° C. or less, 200 × 10 ⁻⁷ / ° C. or less, 180 × 10 ⁻⁷ / C in a temperature range of 0 to 150 ° C. It is preferable that the temperature is lower than or equal to ° C. If the coefficient of thermal expansion is too large, it is likely to be deformed due to a change in temperature, and the light-gathering ability may be reduced, and the sensitivity of the sensor may be reduced. Although the lower limit of the thermal expansion coefficient is not particularly limited, it is practically 50 × 10 ⁻⁷ / ° C. or more.

  For the purpose of improving the infrared light transmittance, an antireflection film may be formed on the surface (the light incident surface or the light emission surface) of the window material 2.

Examples of the structure of the antireflection film include a multilayer film in which high refractive index layers and low refractive index layers are alternately laminated. Materials constituting the antireflection film include Y ₂ O ₃ , Al ₂ O ₃ , SiO, SiO ₂ , MgO, TiO, TiO ₂ , Ti ₂ O ₃ , CeO ₂ , Bi ₂ O ₃ , HfO ₂ , Nb _{2 O 5, La 2 O 3,} Ta 2 O 5, Gd 2 O 3, oxides such as WO _3, hydrogenated carbon, diamond-like carbon (DLC), Ge, Si, ZnS, ZnSe, As 2 S 3, As ₂ Se ₃ , PbF ₂ , metal telluride, metal fluoride (MgF ₂ , CaF ₂ , BaF _2, etc.) are preferred. The material of the refractive index layer may be a resin, and for example, an olefin resin or the like can be used. The antireflection film is not limited to a multilayer film, but may be a single-layer film.

  The shape of the window material 2 is not particularly limited, but is preferably a lens shape such as a biconvex shape (for example, a spherical shape), a plano-convex shape, a meniscus shape, etc. in consideration of the light-collecting ability.

  Next, a method for manufacturing the window material 2 will be described.

  Raw materials are mixed to obtain the above glass composition to obtain a raw material batch. Next, the quartz glass ampule is evacuated while being heated, and then the raw material batch is put in. The quartz glass ampule is sealed with an oxygen burner while evacuating.

As a raw material, an elemental raw material (Te, Ge, Ga, or the like) may be used, or a compound raw material (GeTe, GeTe ₂ , Ga ₂ Te _3, or the like) may be used. These can also be used in combination.

  Next, the sealed quartz glass ampule is heated in a melting furnace to 650 to 1000 ° C. at a rate of 10 to 80 ° C./hour, and then maintained for 6 to 12 hours. During the holding time, if necessary, the quartz glass ampule is turned upside down to stir the melt.

  Thereafter, the quartz glass ampule is taken out of the melting furnace and rapidly cooled to room temperature to obtain a glass base material.

  Subsequently, the obtained glass base material is processed into a predetermined shape (a disc shape, a lens shape, or the like).

  If necessary, an antireflection film is formed on one side or both sides of a glass base material processed into a predetermined shape to obtain a window material 2. Examples of the method for forming the antireflection film include a vacuum deposition method, an ion plating method, and a sputtering method.

  After forming the antireflection film on the glass base material, the glass base material may be processed into a predetermined shape. However, since the antireflection film is likely to be peeled off in the processing step, it is preferable to form the antireflection film after processing the glass base material into a predetermined shape unless otherwise specified.

(Support member 3)
The material of the support member 3 may be either a metal or a ceramic, but is preferably a metal such as Hastelloy (registered trademark), Inconel (registered trademark), or SUS in consideration of workability.

The coefficient of thermal expansion of the support member 3 is 250 × 10 ⁻⁷ / ° C. or less, 220 × 10 ⁻⁷ / ° C. or less, 200 × 10 ⁻⁷ / ° C. or less, 180 × 10 ⁻⁷ / ° C. in a temperature range of 0 to 150 ° C. The following is preferred. If the coefficient of thermal expansion is too large, it is likely to be deformed due to a change in temperature, and the light-gathering ability may be reduced, and the sensitivity of the sensor may be reduced. Although the lower limit of the thermal expansion coefficient is not particularly limited, it is practically 50 × 10 ⁻⁷ / ° C. or more.

(2) Second Embodiment FIG. 2A is a schematic plan view showing an optical component according to a second embodiment of the present invention, and FIG. 2B is a cross-sectional view of an optical component according to a second embodiment of the present invention. It is a typical sectional view showing B section. The optical component according to the second embodiment is different from the optical component according to the first embodiment in that a projection 3d is further provided around the side wall 3c. Providing the protrusion 3d makes it easier to fix the support member 3 in the gas sensor. Further, it becomes easy to align the optical axis of the window member 2 with the optical axis of the support member 3.

  (3) Third Embodiment FIG. 3A is a schematic plan view illustrating an optical component according to a third embodiment of the present invention, and FIG. 3B is a diagram illustrating a C- of the optical component according to the third embodiment of the present invention. It is a typical sectional view showing C section. The difference from the optical component according to the first embodiment is that, in the third embodiment, the side wall 3c has a rectangular cylindrical shape. By forming the side wall portion 3c in the shape of a rectangular tube, the support member 3 can be easily fixed in the gas sensor. Further, it becomes easy to align the optical axis of the window member 2 with the optical axis of the support member 3.

(4) Fourth Embodiment FIG. 4A is a schematic plan view illustrating an optical component according to a fourth embodiment of the present invention, and FIG. 4B is a diagram illustrating an optical component according to a fourth embodiment of the present invention. It is a typical sectional view showing D section. The difference from the optical component according to the first embodiment is that, in the fourth embodiment, a notch 3e is further present in a part of the side wall portion. When a projection corresponding to the notch 3e is provided at a predetermined position in the gas sensor, the notch 3e can be fitted into the projection, so that the positioning of the support member 3 becomes easy. Further, it becomes easy to align the optical axis of the window member 2 with the optical axis of the support member 3.

  It should be noted that the present invention is not limited to the above embodiments, and can be implemented in various other forms without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 Optical component 2 Window material 3 Support member 3a Opening 3b Opening 3c Side wall 3d Projection 3e Notch

Claims (9)

  An optical component, comprising: a window member made of chalcogenide glass; and a support member for supporting the window member.   The support member is a cap member having a cylindrical side wall having an opening at the distal end side and the base end side, and the window material is fixed so as to cover the opening of the cap member. The optical component according to claim 1.   The optical component according to claim 1, wherein the window member has a lens shape.   The optical component according to any one of claims 1 to 3, wherein the chalcogenide glass has a composition of Ge + Ga + Sb + Bi + Sn + In + Ag + Si over 0 to 70% and S + Se + Te over 0 to 90% by mol%.   The optical component according to claim 1, wherein the chalcogenide glass has a maximum transmittance of 40% or more in a wavelength range of 3 to 12 μm at a thickness of 1 mm. The optical component according to claim 1, wherein the chalcogenide glass has a coefficient of thermal expansion of 250 × 10 ⁻⁷ / ° C. or less in a temperature range of 0 to 150 ° C. ⁷ .   The optical component according to claim 1, wherein an antireflection film is formed on a surface of the window material. The optical component according to claim 1, wherein the support member has a coefficient of thermal expansion of 250 × 10 ⁻⁷ / ° C. or less in a temperature range of 0 to 150 ° C. 9.   The optical component according to claim 1, wherein the optical component is used for an optical sensor.