JPH0341404Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to an incandescent light bulb for measurement that is optimal as a light source for various measuring instruments that utilize light, particularly portable measuring instruments. [Background of the invention] Light, especially light in the infrared region, is used as a measurement light source in various measuring instruments. For example, in gas concentration measuring instruments, infrared rays are projected into the gas involved in measurement, and the unique infrared rays of the gas are emitted. The gas concentration is measured by measuring the amount of gas absorbed. The light source for such gas concentration measuring equipment is
For gases whose absorption wavelength is in the near-infrared region, xenon discharge lamps or incandescent lamps with bulbs made of quartz are used, but for gases whose absorption wavelength is in the far-infrared region, such as carbon dioxide, blackbody radiation is used. A blackbody furnace using . [Problems to be solved by the invention] The blackbody furnace does not require a quartz bulb like a xenon discharge lamp or an incandescent lamp, and therefore emits light in a wide range from near infrared to far infrared. Therefore, although it is ideal as a measurement light source, it is generally large and cannot be applied to small measurement equipment, especially portable type measurement equipment. [Means for solving the problem] The present invention includes an enclosure made of a single crystal alumina tube,
a filament provided within the envelope;
An incandescent light bulb that is lit with a power consumption of 10 to 30 W, wherein the filament has a length of 2 mm or less and an outer diameter of 2 mm, and the temperature of the filament during operation is 1800 to 2800 K. do. [Function] According to this configuration, the envelope is made of a single-crystal alumina tube, and since this single-crystal alumina transmits light in the infrared region over a fairly wide range, it has a wide range of spectral radiation characteristics in the infrared region. Moreover, since the filament size is within 2 mm in length and within 2 mm in outer diameter, the filament temperature during operation is 1800 to 2800 K even with low power consumption of 10 to 30 W, making it possible to increase the spectral radiation intensity in the infrared region. can. [Example] The present invention will be described in detail below with reference to the drawings. FIG. 1 shows an embodiment of an incandescent light bulb for measurement according to the present invention. 1 is an envelope, 2 is a filament, and 3 and 4 are leads. The enclosure 1 includes, for example, a cylindrical transparent portion 10 made entirely of a single-crystal alumina tube, and the transparent portion 1.
It consists of caps 11 and 12 made of metal, for example, which hermetically close both ends of the cap. Specifically, a metal layer is fixed to the outer walls of the ends 13 and 14 of the transparent portion 10, and each of these metal layers and the caps 11 and 12 are hermetically connected, for example, by brazing, to form the enclosure 1. can be formed. The filament 2 is made of tungsten, for example, and its both ends are connected to the bases 11 and 12 via leads 3 and 4, respectively. The filament 2 is in the form of a single coil or a double coil, and its axial length L is within 2 mm, and its outer diameter D is within 2 mm. When the filament 2 is made to generate heat, it is energized with a current and voltage controlled so that the power consumption is 10 to 30W. That is, when using a filament 2 whose size is within the above-mentioned range, the filament 2 can be appropriately heated to a temperature of 1800 to 2800K with power consumption of 10 to 30W. When the power consumption is too high, the service life of the light bulb may be shortened due to overheating of the filament 2. On the other hand, when the power consumption is too low, the radiation intensity is so small that light of sufficient intensity for measurement may not be obtained. Furthermore, the supply of power of 10 to 30 W can be easily achieved using a commercially available battery, making it ideal for a portable measurement light source. Furthermore, since the filament 2 is small in size, the light collection efficiency can be increased, and it is easy to form a small diameter beam with high energy density. In FIG. 2, curve I shows the spectral transmittance of single crystal alumina (thickness: 2 mm), and the curve I shows the spectral transmittance of quartz (thickness: 2 mm) for comparison. As can be understood from the figure, single-crystal alumina exhibits high transmittance over a wide range of infrared regions, whereas quartz, which is commonly used as glass for enclosures, has high transmittance in the far-infrared region. Its transmittance is much lower than that of single crystal alumina. In addition, as can be understood from the spectral radiant intensity (relative value) curves at filament temperatures of 1800K, 2300K, and 2800K shown in the same figure, when the filament temperature is within the range of 1800 to 2800K, the spectral radiant It has high intensity and can provide sufficient radiation for practical use. Next, a lighting experiment conducted specifically will be described. <Filament configuration> 〇 Filament length: 1.7mm 〇 Filament outer diameter: 1.2mm 〇 Coil strand diameter: 0.2mm 〇 Number of coil turns: 5.0 turns 〇 Coil pitch: 140% Equipped with a filament with the above configuration We fabricated a large number of measurement incandescent light bulbs according to the present invention, and conducted experiments in which the voltage and current supplied to the filament of each bulb were set to various values and the lights were lit continuously. We investigated the relationship between the lighting time (until the lighting time decreases to 80%). The results are shown in Table 1 below.

[Effect of idea]

According to the incandescent light bulb for measurement of the present invention, the envelope is made of single crystal alumina, and the length of the filament is 2 mm.
Since the outer diameter is within 2 mm, the filament temperature can be increased to 1800 to 2800 K with low power consumption of 10 to 30 W. As a result, despite its small size,
Since it is an incandescent bulb that can efficiently emit light in the infrared region, it can be optimally used as a light source for various measurement devices that utilize light in the infrared region, especially portable types.

[Brief explanation of the drawing]

Figure 1 is an explanatory cross-sectional view showing one embodiment of the incandescent light bulb for measurement of the present invention, and Figure 2 shows the spectral transmittance of single crystal alumina, the spectral transmittance of quartz for comparison, and the filament temperature of 1800K. ，
Spectral radiant intensity at 2300K and 2800K (relative value)
FIG. 3 is an explanatory diagram showing an example of application in measuring the concentration of gas. 1... envelope, 2... filament, 3, 4...
Lead, 10...Transparent portion, 11, 12...Base, 51...Incandescent bulb for measurement, 52...Reflector for focusing, 53...Lens for beam formation, 54...Infrared transmission filter, 55... ...Infrared detector, 5
6...Container.

Claims (1)

[Claims for Utility Model Registration] An incandescent light bulb comprising an envelope made of a single-crystal alumina tube and a filament disposed within the envelope, which is lit with a power consumption of 10 to 30 W, the filament comprising: An incandescent lamp for measurement, characterized in that the length is within 2 mm and the outer diameter is within 2 mm, and the temperature of the filament during operation is 1800 to 2800 K.