JPS62250320A - Thermopile - Google Patents

Abstract

PURPOSE:To receive infrared rays emitted from the end surface of an infrared ray fiber with good efficiency, by downwardly curving a flat gold black on a thermopile chip in a semi-spherical shape. CONSTITUTION:A thermocouple 4 is provided on the SiO2 film 5 formed on an insulating substrate and gold black 2 is formed thereon in a film form through an Si3N4 film 3. In this constitution, a surface receiving infrared rays from the end surface of an infrared ray optical fiber 1 is formed on a semi- spherical gold black 2. By this method, the hot contact of the thermocouple 4 is provided along the surface of the gold black 2 and, therefore, the heat from the fiber 1 can be received efficiently.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a thermopile, and particularly improves efficiency when spatially optically coupling the end face of an infrared optical fiber to the all-black surface, which is a heat absorber on a thermopile chip. Concerning thermopiles that can focus light well.

[Conventional technology]

Conventionally, a thermopile used as an infrared detector has a large number of thermocouples formed on an insulating substrate, and these thermocouples are connected in series.

However, in order to increase the output, which is directly related to the sensitivity, the density of each thermocouple was made as large as possible.

[Problem that the invention seeks to solve]

Also. The conventional spatial optical coupling method of a planar all-black thermopile and the end face of an infrared optical fiber does not have good light receiving efficiency. Now, in Fig. 3 (A), from the equation for illuminance due to a completely diffused surface light source, if the illuminance at point P is E, then E is as follows: R: Distance θ: Angle with the normal to the emission surface ψ: Light reception Angle L with the normal line of the surface: Brightness.

Therefore, the area of the end face of the infrared optical fiber 200 is πγ”(
ds==πγ2), the illuminance E at point P from equation (1) is: =πLAcosOcosψ ゛°″゛°°°
Song (2) γ2 However, A=-. Therefore, let's now consider the planar all black shown in FIG. 3(B). Since the illuminance EA at point A on the planar completely black 100 in FIG. 3(B) is O (zero) for both ψ and θ, from the above equation (2), E^=πLAcosθ coaψ =xLAcosO"coso" Next, the third Infrared optical fiber 2 as shown in Figure (C)
The illuminance EB at a point B shifted from the vertical lower point A of 00 is:
Since both ψ and θ exist, from the above equation (2), EB=πLBcosθcosψ γ2 However, B=−R'2 R'=Rcos θ R'>R.

In addition, the end face of the infrared optical fiber 200 and the planar fully black surface 1
Since 00 is parallel, each normal line n and n' becomes ψ=0 from the parallel condition. Therefore, the illuminance E at point B
B becomes Ee=πLBcos''ll+ γ2 A>B.

From this, the illuminance at point B on the 8th is greater than the illuminance at point A.
It becomes weaker by the amount multiplied by QOB"θ.

Furthermore, due to minute positional changes in the end face of an infrared optical fiber having a certain spread angle, infrared rays may warm up areas on the thermopile chip other than the completely black area on the plane (for example, the cold junction of a thermocouple).

Furthermore, it is not possible to directly couple the end face of an infrared optical fiber to the entire planar surface of the thermopile.

[Purpose of the invention]

An object of the present invention is to provide a thermomobile that can spatially efficiently couple the end face of an infrared optical fiber and the entire black on a thermopile chip.

[Means for solving problems]

The principle of the present invention is as follows. That is, in the present invention, as shown in FIG. 2, a completely black 6o, which is a receiving surface for infrared rays emitted from an end face of an infrared optical fiber 5o, is formed in a hemispherical shape.

Therefore, the hemispherical full black 6 shown in FIG. 2(A) now
Since both θ and ψ of illumination intensity EA' at point A' on plane 0 are zero, EA'=πLAcosO'coso'=zLAγ2 where A==−R” from equation (2).

Furthermore, the illuminance EB' at point B' on the hemispherical black 6° plane shown in FIG. 2(B) is 0, but ψ is zero, so
2) From the formula, EB' = sLAc o sθc o s O@=gL
Aco sθ However, A == '.

Therefore, the illuminance EB' becomes weaker than the illuminance E^' by an amount multiplied by coso. By the way, E8 in the case of flat black
is weakened by the product of QOB"θ and B. However, as in the present invention, in the case of hemispherical full black, E B/ is weakened by the amount multiplied by aosf), so the overall The illuminance is E8'〉Ell.In addition, even if there is a slight change in the position of the fiber end face with a certain divergence angle,
If the radius of curvature of the hemispherical black on the thermopile chip is determined appropriately, heating of other places (for example, the cold junction of the thermocouple) with infrared rays will not occur, and the hot junction of the thermocouple on the thermopile chip will not be heated by infrared rays. Since the Si3N4 film is sandwiched and runs along the hemispherical black surface, heat is efficiently absorbed and removed.

In this way, one aspect of the present invention is to make it possible to efficiently condense radiation from the fiber end face by digging down the planar black area on the thermopile chip in a hemispherical shape.

That is, the present invention provides a device in which a full black film is formed on a thermocouple provided on a silicon oxide film formed on an insulating substrate with a silicon nitride film interposed therebetween.
The device is characterized in that the completely black surface that receives the infrared rays from the end face of the infrared optical fiber is formed into a hemispherical shape.

〔Example〕

An embodiment of the present invention will be described below.

FIG. 1 shows an embodiment of the invention.

In the figure, 1 is an infrared optical fiber, 2 is a hemispherical black,
3 is Si, N4 film, 4 is thermocouple, 5 is SiO2 film,
6 is Si, N, film, 7 is SiO, 8 is Si, N,
The film 9 is a Si substrate. In examples, S i O
Since the hot junction of the thermocouple 4 formed on the two membranes 5 is provided along the two hemispherical black surfaces, according to this embodiment, the heat from the infrared optical fiber 1 can be efficiently received. I can take it.

Further, the hemispherical fully black 2 in this embodiment can efficiently receive infrared rays emitted from the end face of the infrared optical fiber 1.

〔Effect of the invention〕

As explained above, according to the present invention, the end face of an infrared optical fiber and the entire black on the thermopile chip can be spatially and efficiently coupled.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a thermopile showing an embodiment of the present invention;
FIG. 2 is a diagram for explaining the present invention in detail, and FIG. 3 is a diagram for explaining the problems of the conventional thermopile. 1... Infrared optical fiber, 2... Hemispherical black, 3... Si, N4 film. 4...Thermocouple. 5...S i O, membrane. 6...Si3N, film, 7...Sin, 8...Si3N4 film. 9...Si substrate.

Claims (1)

[Claims] (1) A gold black film formed on a thermocouple provided on a silicon oxide film formed on an insulating substrate via a silicon nitride film, in which the end face of the infrared optical fiber is A thermopile characterized by having a hemispherical surface that receives infrared rays.