JPH0642181Y2 - Thermal conversion type optical power measuring instrument - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" This invention is, for example, a thermal conversion type optical power measuring device for measuring the power of light emitted from a laser light source or the power of light coming through an optical fiber. Regarding

"Prior Art" Fig. 2 shows the structure of a conventional heat conversion type optical power measuring instrument.
The figure shows the sensor part of the optical power meter. In the figure, 1 indicates a metallic case. The light-heat conversion element 3 is supported by a support 2 made of a heat insulating material in the case 1.

The light-heat conversion element 3 is made of, for example, a metal having gold black evaporated on its surface, and the gold black efficiently converts light energy into heat. A light inlet 4 is provided on the front side of the case 1, and the light to be measured enters the light-heat conversion element 3 through the light inlet 4.

A heat-electric conversion element 5 such as a thermocouple is attached to the back side of the light-heat conversion element 3, and the amount of electricity generated in the heat-electric conversion element 5 is measured by, for example, a digital voltmeter (not particularly shown), The power of the light incident on the light-heat exchange element 3 is measured.

A cap 6 is configured to be attached to the light inlet 4, and the cap 6 prevents dust or the like from entering the case 1 when not in use.
It is also used as a shutter for blocking the light intake port 4 when the zero point of the optical power measuring device is measured by the zero point adjusting unit.

[Problems to be Solved by the Invention] As described above, the cap 6 is not only a dustproof cap but also an optical shutter at the time of zero point adjustment performed before starting the use of the heat conversion type optical power measuring instrument. .

Here, regarding the measurement result of the conventional example of this heat conversion type optical power measuring instrument, there is a direct influence on the measurement accuracy of the case 1, the light-heat exchange element 3, the support 2, the heat-electricity conversion element 5, and the like. The members to be given are almost the same as those in the conventional example, but the measurement results of the thermal conversion type optical power measuring instrument and the conventional example of the above-mentioned thermal conversion type optical power measuring instrument in which the shapes and materials of the light inlet 4 and the cap 6 are different. Although I have tried to compare the measurement results with the above, there was a slight difference between the two. Various studies have been conducted on the reason why the measurement results are different, but the conclusion has not been easily obtained.
However, at one point, it was found that the zero point adjustment performed prior to starting the use of the thermal conversion type optical power measuring instrument had an influence on the measurement result.

That is, in the conventional example of the heat conversion type optical power measuring device, the cap 6 is made of a metal material having good heat conduction and radiation. At the time of zero-point adjustment by the zero-point adjusting unit, which is carried out prior to starting the use of the heat-conversion-type optical power measuring instrument, the metal cap 6 is manually attached to the light-intake port 4 and the heat-conversion-type optical power measuring instrument is used. Although the light incident on is blocked, the heat is easily conducted and accumulated by the human hand to the metal cap 6 having a high thermal conductivity. As a result of heat being conducted and accumulated in the metal cap 6, the temperature of the metal cap 6 rises. The metal cap 6 continues to radiate heat energy until its temperature drops to the ambient temperature. Radiant heat energy caused by the temperature rise of the metal cap 6 is converted into the light-heat conversion element 3.
It was found that the measurement results were indefinite due to the fact that the zero point adjustment was carried out while affecting the.

It is necessary to wait for the zero point adjustment to be performed until the temperature of the metal cap 6 is reduced to the ambient temperature, but this requires a considerable amount of time and the zero point adjustment must be waited for a long time. This is inconvenient in measurement efficiency.

An object of the present invention is to provide a heat conversion type optical power measuring instrument which can perform adjustment for setting a zero point immediately after mounting the cap 6.

"Means for Solving the Problem" This invention is provided with a light inlet for taking in the light to be measured, and a light-heat conversion element for receiving the light to be taken in is provided near the light inlet. A heat-electric conversion element for converting the amount of heat energy generated in the light-heat conversion element into the amount of electric energy;
In a heat conversion type optical power measuring instrument comprising a zero point adjusting section and a dustproof light blocking cap for closing the light inlet,
The dustproof light blocking cap was made of a synthetic resin having a low thermal conductivity, and constituted a heat conversion type optical power measuring instrument that was long in the light taking-in direction.

According to the structure of the present invention, the cap is made of the resin material and is elongated in the light-receiving direction, so that even if a person touches the cap, the heat transferred to the cap is very small.

For this reason, according to this invention, it is possible to perform the adjustment for setting the zero point immediately after the cap is attached to the light inlet.

"Embodiment" FIG. 1 shows an embodiment of the present invention. In FIG. 1, 1 is a case, 2 is a support, 3 is a light-heat conversion element, 4 is a light inlet, and 5 is a heat-electricity conversion element, which is the same as the conventional one.

In this invention, the dustproof light blocking cap for closing the light inlet 4 is made of synthetic resin having a low thermal conductivity,
The length is long in the light capturing direction. As the resin material, select a material having a low thermal conductivity, such as vinyl chloride, preferably molded with a black colored resin,
It has a structure that blocks the transmission of light.

Further, the length l of the cap 6 is formed to be twice as long as that of the conventional cap so that the heat transferred from the human hand is not transferred to the tip side of the cap 6, that is, the portion facing the light-heat conversion element 3. It is possible.

[Advantage of Device] As described above, according to this device, the cap 6 is made of the resin material, and therefore, even if the user holds the cap 6 by hand and attaches it to the light inlet 4, The amount of heat transferred to 6 is very small, and the heat from human hands is not accumulated in the cap 6.

Therefore, even immediately after the cap 6 is attached, the amount of heat radiated from the cap 6 to the light-heat exchange element 3 can be made minute. As a result, the adjustment for setting the zero point can be performed by the zero point adjusting unit even immediately after the cap 6 is attached, and the optical power can be measured without taking time.

Further, by forming the length 6 of the cap 6 longer than that of the conventional one as in the above embodiment,
That is, the amount of heat transferred to the side facing the light-heat conversion element 3 can be further reduced.

Therefore, the amount of heat radiated from the cap 6 to the light-to-heat conversion element 3 can be reduced by increasing the length 1 of the cap 6 as described above. Therefore, the error at the time of the zero point adjustment can be reduced, and the optical power measuring device can be configured to be more convenient.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view for explaining a conventional technique. 1: case, 2: support, 3: light-heat conversion element, 4: light inlet,
5: Heat-electricity conversion element, 6: Cap.

Claims (1)

[Scope of utility model registration request] 1. A light-to-heat conversion element having a light-intake port for taking in the light to be measured, and a light-to-heat conversion element for receiving the light to be taken in is provided near the light-intake port. A heat-electric conversion element for converting an amount of heat energy into an amount of electric energy;
In a heat conversion type optical power measuring instrument comprising a zero point adjusting section and a dustproof light blocking cap for closing the light inlet,
A heat conversion type optical power measuring device characterized in that the dustproof light blocking cap is made of synthetic resin having a low thermal conductivity and is long in the light taking-in direction.