JPH0450623A - Illuminance detecting sensor - Google Patents

Abstract

PURPOSE:To detect the illuminance in a minute region in high accuracy by masking a slit for setting a detecting field of view with a thin film in a filter, and detecting the light of the wavelength component in a standard spectral luminous efficiency region. CONSTITUTION:A filter 3 for cutting the light of the wavelength component at the outside of a standard spectral luminous efficiency region is arranged at the front surface of a photodetector 1. In the filter 3, a slit 4 for setting a detecting field of view is masked with a thin film. When this sensor is attached to an illuminance-distribution measuring device, the light only in the minute region in the light from an object to be measured is transmitted through the slit 4. The light of the wavelength component at the outside of the standard spectral luminous efficiency region is cut with the filter 3. The light reaches a light receiving surface 2 of the photodetector 1, and the electric output corresponding to the illuminance value is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an illuminance detection sensor that detects the illuminance or illuminance distribution of a light source of a copying machine or the like.

2. Description of the Related Art A conventional illuminance detection sensor will be described below with reference to the drawings.

FIG. 2 is a schematic diagram of an apparatus for measuring illuminance distribution.

In the figure, 6 is a light source as an object to be measured.

7 is an illuminance detection sensor, which is driven by stages 8 and 9 in the longitudinal direction and width direction of the light source 6;
a and 10b are arranged at an arbitrary distance from the object to be measured 6. The output of the illuminance detection sensor 7 is input to an analysis device 11, which displays the illuminance distribution of the object to be measured 6.

FIG. 3 is a schematic diagram of a conventional illuminance detection sensor. In the figure, reference numeral 1 denotes a light-receiving element such as a photodiode and has a light-receiving surface 2. As shown in FIG. A slit 5 is arranged in front of the light receiving surface 2 to set a detection field of view.

Problems to be Solved by the Invention However, in the conventional illuminance detection sensor described above, the spectral sensitivity of the light receiving element and the standard luminous efficiency do not match, so light in a wavelength band outside the standard luminous efficiency is detected, resulting in false detection when measuring illuminance. There was a problem with doing this.

Further, if the slit is thick, obliquely incident light is rejected, and if the slit is thin, the slit itself is distorted, both of which have a negative effect on the light receiving angle characteristics.

The present invention solves the above-mentioned conventional problems, and is capable of detecting light of wavelength components in the standard luminous efficiency range without being affected by the characteristics of the light-receiving element, and is capable of detecting illuminance in a minute area with high precision. The purpose is to provide sensors.

Means for Solving the Problems To achieve this object, the present invention includes a filter that cuts light of wavelength components outside the standard ratio visibility range, and a slit for setting a detection field of view arranged in the filter. is characterized in that the filter is masked by a thin film formed by vapor deposition or the like.

Effects of the Invention According to the present invention, illuminance can be measured without being affected by the spectral sensitivity characteristics of the light receiving element by using a filter that cuts light of wavelength components outside the standard ratio visibility range.

Furthermore, by masking the slit for setting the detection field of view with a thin film such as vapor-deposited film, a slit that has almost no adverse effect on the acceptance angle characteristics can be constructed, that is, the illuminance in a minute area can be detected with high precision.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of the illuminance detection sensor of this embodiment.

In the figure, reference numeral 1 denotes a light-receiving element such as a photodiode and has a light-receiving surface 2. As shown in FIG. A filter 3 is disposed in front of the light receiving element 1 for canting light having wavelength components outside the standard ratio visibility range, and a slit 4 for setting a detection field of view is masked with a thin film in the filter 3.

When this sensor is installed in the illuminance distribution measuring device shown in Fig. 2, the light from the object to be measured is transmitted through the slit 4 in only a minute area, and the filter 3 filters out the wavelength components outside the standard ratio visibility area. The light is cut off and reaches the light-receiving surface 2 of the light-receiving element 1, generating an electrical output corresponding to the illuminance value.

As described above, according to this embodiment, the filter 3 allows
Since light having wavelength components outside the standard ratio visibility range can be cut, illuminance can be measured without being affected by the spectral sensitivity characteristics of the light receiving element 1. Furthermore, the slit 4 masked by a thin film formed by vapor deposition or the like allows illuminance to be measured with almost no adverse effect on the acceptance angle characteristics.

In the above embodiment, a slit is used to set the detection field of view, but it goes without saying that a pinhole may be used depending on the measurement method.

Effects of the Invention As described above, according to the present invention, the illuminance can be measured without being affected by the spectral sensitivity characteristics of the light receiving element, and the illuminance can be measured with high precision in a minute area with excellent acceptance angle characteristics. A detection sensor can be realized.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an illuminance detection sensor according to an embodiment of the present invention, FIG. 2 is a schematic diagram of an illuminance distribution measuring device, and FIG. 3 is a schematic diagram of a conventional light intensity detection sensor. 1... Light receiving element, 2... Light receiving surface, 3...
...Filter 4...Slit.

Claims (2)

[Claims] (1) In an illuminance detection sensor that uses a light receiving element to detect illuminance or illuminance distribution in a minute area of a light source, there is a filter that cuts light of wavelength components outside the standard ratio visual field, and a detection field setting for the filter. An illuminance detection sensor characterized by having a slit. (2) The illuminance detection sensor according to claim 1, wherein the slit is masked by a thin film.