JPH04128619A - Radiation-illumino-meter - Google Patents

Abstract

PURPOSE:To retain a photocurrent which a light receiving device generates independently of the intensity of light of a light source within a constant range always by installing a variable throttle to adjust the quantity of the light injected to the light receiving device automatically in stages in a photo-receptor. CONSTITUTION:A printed board 3 having circuits to amplify the photocurrent from a light receiving device 12, carry out A/D conversion, and operation is installed in the inside of a case and two displaying devices 4 are so arranged in parallel up and down in the opposite side to a photo-receptor 2 in the case as to be exposed only in the displaying parts and the one in the upper side is for displaying the radiation exposure (display unit MJ/m<2>) and the one in the lower side is for displaying the instant value of irradiance (display unit W/m<2>). The variable throttle 10 is able to adjust the quantity of the light to be injected to the light receiving device 12 automatically in stages based on the intensity of the light to be injected to the light receiving device 12. In both cases where the intensity of the light to be injected to the light receiving device 12 is strong and/or weak, the light intensity which the light receiving device 12 receives is made to be within a range where the intensity is in proportion to the photocurrent the light receiving device 12 sends out.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an irradiance meter that can stably measure irradiance and radiation exposure (integrated irradiance) regardless of the intensity of light from a light source.

[Prior art and its problems] FIG. 5A is a sectional view of a light receiver 2' conventionally used in an irradiance meter.

In the figure, in this light receiver 2', light that has passed through a transparent plate 7 of a light entrance window 6 is diffused in all directions inside a light diffusion plate 9, and the diffused light is guided to a wavelength selection filter 11 to select a specific wavelength. The structure is such that only light in a wavelength range of, for example, 300 to 400 nm can enter the 12 light receiving elements. The light-receiving element 12 transmits a photocurrent proportional to the intensity of the light it receives, and the irradiance and radiation exposure in a specific wavelength range are measured through an amplifier, an A/D converter, an arithmetic circuit, etc. (not shown), and the irradiance is measured in a specific wavelength range. This is what is displayed on the display.

Now, as shown in FIG. 4, the output characteristics of the photocurrent of the light-receiving element 12 increase or decrease in proportion to the intensity of light received by this element 12, but when the intensity exceeds a certain level, this proportional relationship can no longer be obtained. . Therefore, if a proportional relationship cannot be obtained,
For example, by providing a light amount adjusting plate 21 or a neutral density filter (not shown) as shown in FIG. I corrected it like this. Furthermore, even if a proportional relationship is obtained, if the intensity of light is low, the output current will also be small. Electrical noise caused by such factors becomes relatively large compared to the output current, making it impossible to obtain accurate values. For this reason, although not shown, the fifth
The light entrance window 6, light diffusing plate 9, etc. of the light receiver 2' in FIG.

Incidentally, in accelerated light tests, methods are sometimes adopted in which the sample is moved closer to the light source to accelerate the rate of photodegradation, or the sample is moved further away to slow down the rate of photodegradation. When measuring this irradiance and radiation exposure amount, depending on the positional relationship between the light source and the light receiver, as described above, if the amount of light incident on the light receiving element is too large and the intensity of the light is too strong, use a light amount adjusting plate or A light receiver that meets each test condition is equipped with a neutral density filter, and if the light intensity is too low due to the amount of light being too low, the receiver's light entrance window and light diffusion plate are made larger. It is necessary to use Therefore, in order to accurately measure irradiance and radiation exposure, it is necessary to prepare multiple receivers according to each test condition and replace them for each test, which is time-consuming and expensive for equipment. It was not economical.

Furthermore, although not shown in the figure, the operating power for conventional devices was supplied from outside the device through a power line, which meant that equipment was expensive in places where electricity could not be easily supplied, such as in large exposure areas, and accelerated light testing For in-flight use, the light source is generally mounted in the same position as the sample rotating around it, requiring a complex and expensive power supply mechanism such as a slip ring.

However, even when power is supplied in this manner, electrical noise due to wiring and the like increases, causing variations in measured values.

Therefore, regardless of the strength of the light from the light source, there is little change in the amount of light incident on the light receiving element, the output current of the light receiving element can always be kept within a certain range, and can be used for various test conditions, and it is not necessary to supply power from outside the device. There has been a desire to develop an irradiance meter that can be easily installed in any location or device and that can accurately measure irradiance and radiation exposure.

[Means and effects for solving the invention] In order to solve the above problems, the light receiver is provided with a variable diaphragm that automatically and stepwise adjusts the amount of light incident on the light receiving element, and the intensity of the light from the light source is adjusted. The method is to always maintain the photocurrent output by the light-receiving element within a certain range regardless of the current. Therefore, when the light from the light source is strong, the amount of light that enters the photodetector is reduced to weaken the intensity of the light, and when the light from the light source is weak, the amount of light that enters the photodetector is increased to reduce the intensity of the light. This allows the output current of the light receiving element to be always within a certain range regardless of the strength of the light, making it possible to accurately measure irradiance and radiation exposure.

In addition, since we have integrated a solar cell that converts the light from the light source into the operating power of the device, it is possible to use the power supply equipment and power supply mechanism in places without power supply equipment or in accelerated light test machines. There is no need to spend more money, and there is less electrical noise that can affect the measurement results.

[Example〕 Hereinafter, one embodiment of the present invention will be described using each drawing.

FIG. 1 shows the configuration of the irradiance meter of the present invention, with A being a sectional view and B being a perspective view thereof.

In the figure, an irradiance meter 1 includes a photoreceiver 2, a printed circuit board 3 having circuits for amplifying, A/D converting and calculating the photocurrent to be outputted, and a display 4 for displaying irradiance and radiation exposure. , a solar cell 5, etc., which converts light from a light source and serves as an operating power source for this irradiance meter 1.

The light receiver 2 has one end face of a cylinder as a light entrance window 6 through which light enters, and a transparent plate 7 made of quartz glass is closely fixed to this face, and the other end face is closed to create a hermetically sealed interior that prevents rain and dust from entering. A shaped receiver case 8, a light diffusion plate 9 that diffuses incident light in all directions, a variable aperture 10 that automatically and stepwise adjusts the amount of incident light (details will be described later), and a
300 to 400 nm by combining filters that cut light with wavelengths less than nm and light with wavelengths exceeding 400 nm.
A wavelength selection filter 11 that allows only light in a wavelength range of (The surface that closes the other end surface of the cylinder) is configured with a silicon photodiode as a light receiving element 12 that outputs a photocurrent in proportion to the light intensity. Moreover, this light receiver 2 is housed in this case 1 within a rectangular parallelepiped-shaped case 13.
3, with only the light entrance window 6 exposed at the center.

Inside the case 13, a printed circuit board 3 having a circuit for amplifying, A/D converting, and calculating the photocurrent from the light receiving element 12 is arranged, and a display 4 is located inside the case 13 in which the light receiving element 2 is arranged. Two pieces are arranged on the opposite side, with only the display part exposed. W/m2).

On the surface of the case 13 where the light incidence window 6 of the receiver 2 is exposed, one flat solar cell 5 is placed in close contact with the window without covering the window. battery 5
When the solar cell 5 stops functioning when the light from the light source disappears, for example in dark conditions in an accelerated light test or at night in an outdoor exposure test,
An auxiliary battery 14 is provided for retaining the displayed contents.

Incidentally, the case 13 has a sealed structure to protect the inside from rain and dust, and the light receiver 2 and each display 4 are fixed to the case 13 via gaskets (not shown) or the like.

By the way, it is known that the liquid crystal sandwiched between two electrodes generally becomes regularly arranged when a certain voltage is applied to the picture electrode, and that the amount of light transmitted can be adjusted in this state by combining various polarizing plates. It is being

The aforementioned variable diaphragm 10 is an application of this principle, and is capable of automatically and stepwise adjusting the amount of light incident on the light receiving element 12 in accordance with the intensity of light incident on the light receiving element 12.

FIG. 2 is a schematic cross-sectional view of this variable aperture 10, showing a glass substrate 15 on which electrodes 15a of a certain pattern (see FIG. 3) are deposited on one surface of a disk-shaped glass plate, and this substrate construction 5. A glass substrate 16 with an electrode 16a deposited around it,
The vapor deposition surfaces are placed facing each other with a certain gap left between them, the periphery is sealed with a sealant 17, and the gap is filled with liquid crystal 18. Further, on the opposite side of the glass substrates 15, 16 to the surface on which the electrodes 15a are deposited, polarizing plates 19, 2 are provided.
0 is closely attached.

FIG. 3A shows electrode 1 deposited on glass substrates 15 and 16.
In the pattern diagram 5a, portions a and b are the deposition surfaces of the electrodes 15a. Here, when electricity is applied to the electrodes 15a of the glass substrates 15 and 16 (portion a in FIG. 3A), the arrangement of the liquid crystals in the portion sandwiched between the two electrodes becomes regular in a certain direction, and the polarizing plate 19 By interaction with .20, the amount of light transmitted in this part can be significantly reduced (see Figure 3 C).Furthermore, when the electrode of this part b is also energized, the amount of light transmitted in part b can be significantly reduced as well ( Figure 3C
reference).

Figure 4 shows the intensity of light incident on the light receiving element 12 and the light receiving element 1.
2 is a graph of the relationship with the output current of No. 2.

In this figure, the intensity of light incident on the light receiving element 12 is A
If the value exceeds the current, the proportional relationship between the light intensity and the output current disappears, so as shown in Figure 3C, electricity is applied to parts a and b of the glass substrates 15 and 16 to significantly reduce the incident light from these parts. to reduce the amount of light incident on the light receiving element 12,
If it is less than B, increase the amount of light that enters the light receiving element 12 without energizing parts a and b (see the third diagram) so that the intensity of the light that enters the light receiving element 12 is always equal to A-B. It can be adjusted step by step to fit the desired range.

In addition, when the intensity of the light incident on the light receiving element 12 is in the range A-B, as shown in FIG. This is a significant reduction.

Further, as shown in FIG. 4, even if the intensity of light incident on the light receiving element 12 is the same, if the amount of light incident on the light receiving element 2 exceeds A or B, 1. Since each case in the range A-B is different, the output state of the photocurrent for each case is memorized in advance, and the output state of the photocurrent is adjusted according to each state of the variable aperture 1o (see Fig. 3 B, C, and D). Illuminance and radiation exposure are determined.

In addition, in the case of tree removal, a liquid crystal is used for the variable diaphragm in configuration 1-, but if it is possible to accurately adjust the amount of light incident on the light receiving element according to the intensity of the light incident on the light receiving element, a mechanical type, such as a photographic one, may be used. It is also possible to use one with a similar structure to the aperture of the machine.

[Effects of the Invention] The irradiance meter of the present invention configured as described above can automatically and stepwise adjust the amount of light incident on the light receiving element in accordance with the intensity of the light incident on the light receiving element. Regardless of whether the intensity of the incident light is strong or weak, the light intensity received by the light receiving element can be kept within a certain range that is proportional to the photocurrent output by the light receiving element.

Therefore, for example, when conducting an accelerated radiation test with different acceleration speeds by changing the distance between the light source and the sample, conventionally, a plurality of irradiances 81 (equipped with a light intensity adjustment plate or a neutral density filter) according to this distance, However, the irradiance meter of the present invention can handle all conditions with a single unit, always maintains the above proportional relationship, and is electrically (It is possible to make very accurate measurements, is economical, and saves labor because there is no need to replace it depending on the test conditions.)Furthermore, it uses a solar battery as the operating power source. Therefore, there is no need to supply electricity from outside, and it can be easily distributed and installed in any place and in any power production facility, and it is economical and requires no wiring for power supply. This eliminates the electrical noise caused by the slitting and twisting mechanisms, making it possible to perform measurements with even greater accuracy.

[Brief explanation of drawings]

Fig. 1 shows the configuration of the present invention, A is a cross-sectional view thereof, B is a perspective view, Fig. 2 is a cross-sectional view of a variable aperture, Fig. 3 A is a pattern diagram of an electrode deposited on a glass substrate, and B to D of the same figure. 4 is a graph showing the relationship between the light intensity received by the light receiving element and the output current of the light receiving element. FIG. 5A is a cross-sectional view of the light receiver of a conventional irradiance meter. B is a plan view of the light amount adjustment plate. 1....Radiance meter, 2.2'...Receiver, 3...
・Prereto base, 4...Display device, 5...Solar cell, 6
...Light entrance window, 7...Transparent plate, 8...Receiver case, 9...Light diffusion plate, 10...Variable aperture, ]1...
・Wavelength selection filter, 12... Light receiving element, 13...
Case, 14... Auxiliary battery, 15... Glass base,
15as16a...electrode, 17...sealant, 18.
...Liquid crystal,]9.20...Polarizing plate, 21...Light amount adjustment plate. dt energizing h @ 盛 energizing 1- 1 Figure 4 Figure 5

Claims (2)

[Claims] (1) A device that measures and displays the irradiance and radiation exposure of a light source, in which the receiver is equipped with a variable diaphragm that automatically and step-by-step adjusts the amount of light incident on the light receiving element. An irradiance meter characterized by measuring and displaying irradiance and radiation exposure by always keeping the photocurrent output by a light-receiving element within a certain range regardless of its intensity. (2) The irradiance meter according to claim (1), further comprising an integral solar cell that converts light from the light source into an operating power source for the device.