JP2003270125A - Infrared ray source - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently irradiate a desired object with an infrared ray. <P>SOLUTION: This infrared ray source is provided with a film like heating element 1 heated under an energizing condition, a central electrode part 2 connected electrically to the central part of the heating element 1, and a peripheral electrode part 3 connected electrically to a peripheral edge part of the heating element 1. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, a non-dispersive infrared analyzer (NDIR: Non Dispersi).
VE Infrared Analyzer) and the like.

[0002]

2. Description of the Related Art As the infrared light source, a light source 5 as shown in FIG. 4 is generally used. That is, in this figure, 6 is a filament, such as Fe, N
A wire material having an appropriate diameter and made of an alloy having a large heat resistance (for example, nichrome wire) containing i, Al, Cr or the like as a main component is formed in a coil shape. A conductive can 7 holds the filament 6 in the vertical direction, and is composed of a cylindrical body portion 8 and upper and lower lid portions 9 and 10. And filament 6
One end side of the can 7 is inserted through an electrically insulating hermetic seal 11 such as glass, and the can 7 has an upper lid 9 and a lower lid 10.
Is formed as. The other end of the filament 6 is welded to the upper lid 9 of the can 7.

In the infrared light source 5 having the above structure, the filament 6 is energized by connecting a predetermined power source between the can 7 and the terminal portion 12, and the filament 6 emits infrared rays. is there.

[0004]

However, in the infrared light source 5 having the above structure, the filament 6 has a coil shape, and the infrared rays from the filament 6 cannot be efficiently irradiated to a desired object. As a result, the running cost was increased.

The present invention has been made in view of the above matters, and an object thereof is to provide an infrared light source capable of efficiently irradiating a desired object with infrared rays.

[0006]

In order to achieve the above object, the infrared light source of the present invention has a film-like heating element that generates heat when energized, and an electric power is applied to the central portion of the heating element. And a peripheral electrode portion electrically connected to the peripheral portion of the heating element (claim 1).

The heating element may be formed of graphite, and the central electrode portion and the peripheral electrode portion may both be formed of Au (claim 2).

With the above structure, it is possible to provide an infrared light source capable of efficiently irradiating a desired object with infrared light.

Further, the central electrode portion and the peripheral electrode portion may be connected to the heating element via a support made of carbon (claim 3). In this case, since the support 4 is made of carbon, it has excellent workability, so that the heating element 1 is connected to the central electrode portion 2 and the peripheral electrode portion 3. The work can be performed more easily.

The heating element may be substantially circular in plan view, and the central portion thereof may be thicker than the peripheral portion (claim 4). In this case, the calorific value of the heating element is made uniform over the entire surface, and the temperature distribution over the entire surface of the heating element can be made uniform.

Further, the section between the central portion and the peripheral portion of the heating element may be curved in cross section (claim 5). In this case, it is possible to absorb the expansion and contraction of the heating element due to temperature changes, and since the infrared light source is less likely to be distorted or cracked, it becomes possible to use the infrared light source for a long period of time. Since the structure has flexibility, it is possible to allow the manufacturing precision to have a slight range, and thus it is possible to reduce the cost.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 (A), (B) and (C) are a plan view, a vertical sectional view and a bottom view schematically showing the configuration of an infrared light source D according to an embodiment of the present invention. The infrared light source D is used, for example, as a light source in an infrared gas analyzer such as the NDIR, and has a film-shaped heating element 1 that generates heat when energized, and the heating element 1
A central electrode part 2 electrically connected to the central part of
A peripheral electrode portion 3 electrically connected to the peripheral portion of the heating element 1 is provided.

The heating element 1 is formed of, for example, graphite so as to have a substantially circular shape in a plan view. Further, it is desirable that the heat generating element 1 be as thin as possible (thin film), and for example, it is formed to have a thickness of 5 to 20 μm.

Furthermore, the resistance value of the heating element 1 can be easily changed and set to a desired value by mixing an appropriate component in the graphite.

The central electrode portion 2 has, for example, a substantially circular shape in a plan view, and the peripheral electrode portion 3 has, for example, a substantially ring (or donut) shape in a plan view. Both electrode portions 2 and 3 are arranged so that the center of the central electrode portion 2 and the center of the peripheral electrode portion 3 are located at substantially the same position.

The both electrode portions 2 and 3 are both A
It is formed by using u and is also soldered to, for example, a printed board (not shown).

Then, the central electrode portion 2 and the peripheral electrode portion 3 are connected to the heating element 1 through the support 4 formed of carbon, respectively. The support body 4 includes a central support portion 4a used for connecting the heating element 1 and the central electrode portion 2 and a peripheral support portion 4b used for connecting the heating element 1 and the peripheral electrode portion 3. In other words, the central support portion 4a has a substantially cylindrical shape, and the peripheral support portion 4b has a substantially ring shape. Since the support 4 uses carbon,
The workability is extremely excellent, and the work for connecting the heating element 1 to the central electrode portion 2 and the peripheral electrode portion 3 can be further simplified.

In the infrared light source D having the above structure, chopped infrared rays can be generated by applying an intermittent voltage between the central electrode portion 2 and the peripheral electrode portion 3.

When a voltage (for example, 2.5 W, 5 V) is applied to both the electrode portions 2 and 3, the heating element 1 is also energized to generate heat, and infrared rays are generated from the heating element 1. become. In order to absorb the expansion and contraction of the heating element 1 due to the temperature change at this time, the section between the central portion and the peripheral portion of the heating element 1 is formed to be curved. More specifically, the heating element 1 is curved so that the central portion thereof is located higher. Since the structure has flexibility as described above, the infrared light source D is less likely to be distorted or cracked, so that the infrared light source D can be used for a long period of time. By providing the flexibility, it is possible to give the manufacturing accuracy to some extent, and it is also possible to reduce the cost.

The infrared light source D is an N ₂ (nitrogen) gas or A
By placing in an airtight case (not shown) in which an inert gas such as r (argon) gas is sealed, it is possible to prevent the graphite constituting the heating element 1 from being oxidized. In this case, a part of the closed case is formed of a transparent material that allows infrared rays to pass therethrough, and the infrared ray generated from the heating element 1 is taken out (radiated) to the outside of the closed case through the infrared ray permeable portion. .

In the infrared light source D having the above-mentioned structure, the heating element 1 supported by the support 4 serves as a planar light source that emits ideal whole infrared radiation, and the conventional coiled filament is used. The heat capacity can be made smaller than that of an infrared light source, and the radiation efficiency of infrared rays can be significantly increased.

Considering the amount of heat generated per unit area of the heating element 1, the heating value is proportional to the product of the square of the current and the resistance, and the current density is higher in the central portion of the heating element 1. Further, the resistance value becomes higher as the thickness of the heating element 1 becomes smaller (thinner). Therefore, the heating element 1
However, in this case, the resistance value is substantially equal over the entire surface of the heating element 1, whereas the current density is higher in the central portion of the heating element 1, so the amount of heat generation is higher. Is greater in the central part of the heating element 1,
A temperature distribution in which the temperature is higher in the central portion of the heating element 1 is obtained.

Therefore, in this embodiment, the central portion of the heating element 1 is configured to be thicker than the peripheral portion. That is, the thickness (cross-sectional area) of a portion that is formed so that the heating element 1 becomes thicker toward the center and is a concentric circle centered on the center of the heating element 1, in other words, the heating element 1
By configuring such that the thickness (cross-sectional area) of the portion at the same distance from the center of the heating element is the same, the resistance value becomes lower toward the central portion of the heating element 1, and the product of the square of the current and the resistance is heated. Since the values are substantially the same in any part of the body 1, the amount of heat generated by the heating element 1 is made uniform over the entire surface, and the temperature distribution over the entire surface of the heating element 1 is also made uniform.

In the above embodiment, the heating element 1 is curved so that its central portion is located higher.
The configuration is not limited to this. For example, as shown in FIG. 2, the intermediate portion between the central portion and the peripheral portion of the heating element 1 is curved upward so that the entire longitudinal section of the infrared light source D has a substantially m-shaped configuration. You may.

Further, as shown in FIG. 3 (A), the heating element 1 may have a substantially constant thickness, and may be curved so that the central portion thereof is located higher. On the contrary, on the contrary, the heating element 1 may have a substantially constant thickness and may be curved so that the central portion thereof is located downward.

Further, as shown in FIG. 3B, the heating element 1 may have a substantially constant thickness and a flat shape without being curved.

Further, as shown in FIG. 3 (C), the heating element 1 has a lower surface formed as a flat surface and a step portion 1a projecting upward in the central portion of the upper surface thereof, which is longitudinally cut. The surface may have a substantially convex shape. On the contrary, on the contrary, the heating element 1 has a flat upper surface and a step portion (not shown) projecting downward in the central portion of the lower surface thereof, and the vertical cross section is substantially convex. It may be formed into a shape.

Further, as shown in FIG. 3 (D), the heating element 1 is formed such that the central portion and the lower surface of the upper surface thereof are flat, and the peripheral portion of the upper surface is located below the central portion. In addition, the upper surface is provided with a slope that increases from the peripheral portion to the central portion, and the vertical cross section may have a substantially mountain (Mt. Fuji) shape. On the contrary, as shown in FIG. 3 (E), on the contrary, the heating element 1 is formed such that the central portion and the upper surface of the lower surface thereof are formed as flat surfaces, and the peripheral portion of the lower surface is located above the central portion. Further, the lower surface is provided with an inclination that decreases from the peripheral portion to the central portion, and the vertical cross section may have an inverted shape of a mountain (Mount Fuji) (inverted Fuji).

Further, as shown in FIG. 3 (F), the heating element 1 has a substantially constant thickness except for the peripheral portion, and has a planar shape without being curved. The lower surface of the peripheral portion may be recessed upward.

Further, as shown in FIG. 3 (G), the heating element 1 has a flat lower surface, and is provided with a slope that gradually increases from the peripheral portion to the central portion of the upper surface. May be. On the contrary, as shown in FIG. 3 (H), on the contrary, the heating element 1 is formed such that the upper surface thereof is a flat surface and the lower surface thereof is provided with a slope that gradually increases from the peripheral portion to the central portion. Good.

Further, the heating element 1 is shown in FIG.
When the shapes shown in (E), (F), (G), and (H) are adopted, they may be formed so that the thickness of their peripheral portions is substantially constant.

Further, in the above-described embodiment shown in FIGS. 1 to 3, the heating element 1 is connected to the central electrode portion 2 and the peripheral electrode portion 3 by a support body composed of a central support portion 4a and a peripheral support portion 4b. However, the present invention is not limited to such a configuration, and either one or both of the central support portion 4a and the peripheral support portion 4b may not be used.

Further, in the above embodiment, the central electrode portion 2
The peripheral electrode portion 3 and the peripheral electrode portion 3 are both soldered to the printed board, but the infrared light source D may be held by the conventional can 7 shown in FIG. 4, for example. In this case, the infrared light source D is attached instead of the filament 6, and more specifically, the central electrode portion 2 is inserted through the hermetic seal 11 through the upper lid portion 9 and the lower lid portion 10 of the can 7. Then, the peripheral electrode portion 3 is formed as one terminal portion 12 by projecting below the can 7, and the peripheral electrode portion 3 is welded or adhered to the upper lid portion 9 of the can 7 by a conductive paint (conductive paint). Good.

[0034]

According to the present invention having the above-mentioned structure, the heat capacity can be reduced and the infrared radiation efficiency can be remarkably increased as compared with the conventional infrared light source using the coiled filament. In addition, it is possible to provide an infrared light source that can realize ideal infrared radiation.

[Brief description of drawings]

1 (A), (B) and (C) are a plan view, a vertical sectional view and a bottom view schematically showing the configuration of an infrared light source according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view schematically showing a first modified example of the heating element in the above embodiment.

3A to 3H are vertical cross-sectional views schematically showing the configurations of second to ninth modifications of the heating element in the above embodiment.

FIG. 4 is a perspective view schematically showing the configuration of a conventional infrared light source.

[Explanation of symbols]

1 ... Heating element, 2 ... Central electrode part, 3 ... Peripheral electrode part, D ... Infrared light source.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ichiro Asano             2 Higashimachi, Kichijoin-miya, Minami-ku, Kyoto-shi, Kyoto             HORIBA, Ltd. F term (reference) 2G059 AA01 GG07 HH01 NN05                 3K092 PP20 QA05 QA09 QB15 QB31                       QC02 QC09 QC18 QC25 QC31                       QC38 QC42 QC44 QC52 VV03                       VV22 VV31

Claims (5)

[Claims] 1. A film-shaped heating element that generates heat when energized, a central electrode portion that is electrically connected to the central portion of the heating element, and an electrical connection to the peripheral portion of the heating element. Infrared light source having a peripheral electrode portion that is electrically connected. 2. The infrared light source according to claim 1, wherein the heating element is made of graphite, and the central electrode portion and the peripheral electrode portion are both made of Au. 3. The infrared light source according to claim 1, wherein the central electrode portion and the peripheral electrode portion are connected to the heating element via a support made of carbon. 4. The heating element is substantially circular in plan view,
The infrared light source according to any one of claims 1 to 3, wherein the central portion is thicker than the peripheral portion. 5. The infrared light source according to claim 1, wherein a cross-sectional shape of a portion between the central portion and the peripheral portion of the heating element is curved.