JPH052174B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a light receiving section of an illuminance meter whose spectral sensitivity characteristics accurately match standard luminous efficiency.

Conventional technology There are two important characteristics that an illumination meter should have: one is that the acceptance angle characteristics of the light receiving part match the cosine law, and the other is that the spectral sensitivity characteristics match the standard luminous efficiency. It is consistent. Of these, the latter standard luminous efficiency can be expressed as shown in FIG. The fact that the spectral sensitivity of the light-receiving section matches the standard luminous efficiency means that the output from the light-receiving section changes along the curve in FIG. 5 when monochromatic light of each wavelength is applied to the light-receiving section.

As shown in FIG. 6, the light receiving section of a conventional illumination meter usually has a visibility correction filter 2 arranged above the photoelectric conversion element 1 and having an area equal to or larger than the photoelectric conversion element 1. The spectral sensitivity of the light receiving section is made to match the standard luminous efficiency. However, the spectral sensitivity of the photoelectric conversion element 1 and the spectral transmission characteristics of the visibility correction filter 2 are not necessarily constant and vary depending on the manufacturing lot.
Furthermore, there are variations even within the same lot.
Therefore, even if the spectral sensitivity of a particular photoelectric conversion element 1 and visibility correction filter 2 matches the standard relative luminosity, the spectral sensitivity of a certain photoelectric conversion element 1 and visibility correction filter 2 of the same type may be different. When combining these, the spectral sensitivity may not match the standard luminous efficiency. In addition, 3 is an illuminance meter light receiving part board, and 4 is a light diffusing plate.

Therefore, conventionally, photoelectric conversion elements 1 of the same lot were
The spectral sensitivity of the light receiver can be adjusted by preparing a plurality of photoelectric conversion elements 1 and the spectral transmittance of the visibility correction filters 2, and considering the combination each time. was in line with standard relative luminous efficiency.

Problems to be Solved by the Invention In the light receiving section of such a conventional illumination meter, fine adjustment of the spectral sensitivity is difficult. Due to variations in the luminous intensity, the spectral sensitivity of the light receiving section may not match the standard luminous efficiency, which poses a problem in the reliability of the illuminance value.

The present invention solves the above conventional problems,
It is an object of the present invention to provide a light receiving section of an illuminance meter that allows fine adjustment of spectral sensitivity and can match standard luminous efficiency with high accuracy.

Means for Solving the Problems In order to solve the above problems, the light receiving section of the illumination meter of the present invention includes one photoelectric conversion element and a spectrometer arranged regularly above the photoelectric conversion element. A visibility correction filter consisting of three types of optical filters having different transmission characteristics, and two types of light control filters each having a light shielding part and an opening through which the light passes have different areas and are arranged concentrically;
By rotating one of the types of light control filters, the balance between the amount of light in the long wavelength region and the amount of light in the short wavelength region of the spectral sensitivity of the light receiving section changes, and the other light control filter is rotated. By doing so, the amount of light in the long wavelength region and the short wavelength region of the spectral sensitivity of the light receiving section changes equally.

Effect According to the above configuration, the area ratio of the three types of optical filters constituting the visibility correction filter can be arbitrarily changed by the two types of light control filters,
As a result, it is possible to finely adjust the spectral sensitivity of the light receiving section, and it is possible to finely correct variations in the spectral sensitivity of the light receiving section caused by variations in the spectral sensitivity of the photoelectric conversion element and the spectral transmission characteristics of the visibility correction filter. can.

Embodiment Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 4.

FIG. 1 is an exploded perspective view of a light receiving section of an illuminometer according to an embodiment of the present invention, in which 11 and 12 are light control filters, 13 is a visibility correction filter, 14 is a photoelectric conversion element, and 15 is a light control filter 12. This is a light transmitting plate that is fixed. As shown in FIG. 1, the visibility correction filter 13 includes three types of optical filters 13a to 1.
3c and 13d to 13f are arranged with regularity. In this embodiment, for ease of explanation, the area of each optical filter 13a to 13c and 13d to 13f is divided equally, but in reality, the area of each optical filter 13a to 13c and 13d to 13f is divided equally. It is necessary to set an area ratio that allows the spectral sensitivity when combined to be close to the standard luminous efficiency. Moreover, as shown in FIG.
Change the transmitted light of a to 13c equally (the light amount of the optical filter 13b decreases when the light amount of the optical filters 13a and 13c increases;
The shape and arrangement of the light-shielding portion 11a and the opening portion 11b are such that the amount of light increases when the light amount of the light beams a and 13c decreases. The light control filter 12 rotates the light control filter 12 clockwise and counterclockwise, so that the amount of light from the optical filter 13e does not change and the amount of light from the optical filters 13d, 13
The shape and arrangement of the light shielding portion 12a and the opening portion 12b are such that only the amount of light from f changes. The light transmitting plate 15 that fixes the light control filter 12 has high transmittance and is not wavelength dependent. Note that the optical filter 13 of the visibility correction filter 13
a to 13c are arranged on the inner peripheral side, and the optical filter 13
d to 13f may be arranged on the outer peripheral side. In this case, it goes without saying that the optical control filter 11 may have a small diameter circular shape, and the optical control filter 12 may have a large diameter annular shape. In addition, light control filters 11 and 12
are structured so that they can each rotate independently.

FIG. 2 shows optical filters of the same type as the visibility correction filter 13, that is, optical filters 13a and 1.
3d shows the light-receiving partial photosensitivity when only optical filters 13b, 13e, or optical filters 13c, 13f are equally irradiated with light, and curve a is when only optical filters 13a, 13d are irradiated with light. , curve b represents optical filters 13b and 13e.
Curve c is a spectral sensitivity characteristic curve when only optical filters 13c and 13f are irradiated with light. Further, the curve d is the sum of the curves a, b, and c of the characteristic curves, and indicates the spectral sensitivity characteristic of the light receiving section.

FIG. 3 shows the operating principle of the light receiving section of the illuminance meter. In FIG. 3A, when the light control filter 11 is moved in the direction of arrow A, the amount of light transmitted through the optical filters 13a and 13c increases. At the same time, the amount of light transmitted through the optical filter 13b decreases, and when the optical filter 13b is moved in the direction of arrow B, the optical filter 13b
The amount of light transmitted through the optical filters a and 13c decreases, and the amount of light transmitted through the optical filter 13b increases. Also the third
In FIG. B, when the light control filter 12 is moved in the direction of the arrow A, the amount of light transmitted through the optical filter 13d increases, and the amount of light transmitted through the optical filter 13f decreases, and when the light control filter 12 is moved in the direction of the arrow B,
The amount of light transmitted through the optical filter 13d decreases, and the amount of light transmitted through the optical filter 13f increases.
Note that the amount of light transmitted through the optical filter 13e at this time does not change. However, the above phenomenon occurs only when the light-shielding part (the same applies to the aperture) is located on two adjacent optical filters as shown in Figure 3A and B, and the light-shielding part is removed by moving. If placed on the next adjacent optical filter, the opposite phenomenon will occur.

FIG. 4 shows the spectral sensitivity S(λ) when the photoelectric conversion element 14 and the visibility correction filter 13 are combined.
This figure shows a form in which the luminous efficiency V (λ) deviates from the standard luminous efficiency V (λ), and as shown in Figure 4A, the luminous efficiency V deviates from the standard luminous efficiency V (λ).
(λ), there are cases in which the sensitivity is high in both the short and long wavelength ranges, cases in which the sensitivity is low in both the short and long wavelength areas as shown in Figure 4B, and cases in which the spectral sensitivity is shown in Figure 4C. It can be classified into four cases: a case where S(λ) is shifted entirely to the short wavelength side, and a case where S(λ) is shifted entirely to the long wavelength side as shown in FIG. 4D.

Next, a method for matching the spectral sensitivity of the light receiving section to the standard luminous efficiency will be explained using FIG. 4. If the spectral sensitivity of the light-receiving section is in the form shown in FIG. In FIG. 3A, it is sufficient to move the light control filter 11 in the direction of arrow B, and in the case of the configuration shown in FIG. What is necessary is to reduce the amount of transmitted light, and what is necessary is to move the light control filter 11 in the direction of arrow A in FIG. 3A. At this time, the light control filter 1 in FIG. 3B
2 is fixed. In addition, in the configurations shown in Fig. 4A and B, if the deviation from the standard luminous efficiency is larger in the long wavelength range than in the short wavelength range, after equalizing the deviation between the short wavelength range and the long wavelength range, Perform the following operations. Furthermore, when the spectral sensitivity of the light receiving section is in the form shown in FIG. 4C, it is sufficient to increase the optical filter 13d and decrease the optical filter 13f.
In the configuration shown in FIG. 4D, the number of optical filters 13d can be decreased and the number of optical filters 13f can be increased. In the configuration shown in FIG. 3B, The light control filter 12 may be moved in the direction of arrow B. In addition,
At this time, the light control filter 11 shown in FIG. 3A is kept fixed. In addition, if the above operation does not match the standard relative luminous efficiency, first set the position of the light control filter 12 so that the deviation from the standard relative luminous efficiency in the short wavelength region and the long wavelength region is equal. However, it is sufficient to perform the operations for the configurations shown in FIGS. 4A and 4B, and the deviation of the spectral sensitivity of the light receiving section from the standard luminous efficiency can be corrected.

Effects of the Invention As described above, according to the present invention, the visibility correction filter is composed of three types of optical filters, and the visibility correction filter is combined with two types of light control filters that can individually control the amount of transmitted light from the visibility correction filter. Therefore, the spectral sensitivity of the light receiving section can be finely adjusted, and therefore it can be easily made to match the standard luminous efficiency.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of a light receiving section of an illuminometer according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of the spectral sensitivity characteristics of the light receiving section when only each optical filter in the same light receiving section is irradiated with light. Fig. 3 is an explanatory diagram of the operating principle of the light receiving section, Fig. 4 is an explanatory diagram of the form when the spectral sensitivity of the light receiving section deviates from the standard luminous efficiency, and Fig. 5 is an explanatory diagram of the standard luminous efficiency characteristics. FIG. 6 is a sectional view of a light receiving section of a conventional illuminance meter. 11, 12...Light control filter, 11a, 12
a... Light shielding part, 11b, 12b... Opening part, 13
... Visibility correction filter, 13a to 13f... Optical filter, 14... Photoelectric conversion element.

Claims (1)

[Claims] 1. One photoelectric conversion element, a visibility correction filter consisting of three types of optical filters with different spectral transmission characteristics arranged regularly above the photoelectric conversion element, a light shielding part, and an aperture through which light passes. The spectral sensitivity of the light-receiving part can be adjusted by rotating one of the two types of light control filters. The balance between the amount of light in the long wavelength region and the amount of light in the short wavelength region changes, and by rotating the other light control filter, the amount of light in the long wavelength region and short wavelength region of the spectral sensitivity of the light receiving section changes equally. The light receiving part of the illuminance meter.