JPS58168924A - Device for measuring photoelectric characteristic of photoelectric transducer - Google Patents

Abstract

PURPOSE:To facilitate a radiation comparison between light sources by finding the spectral sensitivity of a photoelectric transducer under the condition of a reference light source, finding illuminance on the surface of a photoelectric transducer and a coefficient of exposure conversion with regard to a light source to be tested, and calculating a photoelectric output from those data. CONSTITUTION:A spectral device 2 separates radiation from the light source 1 to be tested into spectral components and then photoelectric conversion. Photoelectric outputs differing in unit wavelength are A/D-converted in a storage part 3 for radiation intensity by wavelength and stored in a memory. Then, an arithmetic part 4 for the amount of metered light stores data on every unit wavelength corresponding to standard spectral luminous efficiency in a standard spectral luminous efficiency memory and receives data from said storage part 3 and data from a storage part 8 for spectral radiation intensity of reference light source to multiply both data of every unit wavelength by each other. Similarly, a radiant quantity arithmetic part 5 multiplies the data of the storage part 3 by that of a storage part 7 for the spectral sensitivity of a photoelectric transducer to be tested, wavelength by wavelength, and further sums up the products of respective wavelengths. Then, an arithmetic part 6 for the conversion coefficient of the amount of exposure finds the output ratio between the arithmetic parts 5 and 4 to obtain the coefficient of conversion.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photometric device that quantifies radiation from light sources with different spectral distributions for photoelectric conversion elements having different spectral sensitivities based on a photometer.

The radiation of a light source with a spectral distribution mainly in visible light is usually treated as a photometric quantity, and is measured by a photoreceiver whose spectral sensitivity matches the standard luminous efficiency. This makes it easy to compare radiation between light sources, regardless of the spectral distribution of the light sources.

- In contrast, the photoelectric output of a general photoelectric conversion element that does not meet the standard luminous efficiency is usually expressed as a photocurrent per unit irradiance. Generally, to measure irradiance, thermopiles, bolometers, and other types of receivers that measure temperature rise due to radiation are known, but they have some drawbacks, such as the time it takes to separate and calibrate the radiation from the object to be measured and the background radiation. There are many practical problems.

Therefore, the photoelectric output of the photoelectric conversion element is practically expressed as a photocurrent (A/Ix) corresponding to unit illuminance. In this case, since the spectral sensitivities of the illuminance meter and the photoelectric conversion element differ, the photoelectric output of the photoelectric conversion element takes different values even if the illuminance value is the same for light sources with different spectral distributions. Conversely, even if the illuminance is different, the photoelectric output of the photoelectric conversion element may take the same value. That is, each photoelectric output varies depending on the type of photoelectric conversion element and the type of light source. Therefore, in order to obtain these values, it is necessary to prepare and actually measure each photoelectric conversion element and light source, which has the drawback of requiring complicated work each time.

The present invention relates to a new photoelectric characteristic measuring device that eliminates the above-mentioned conventional drawbacks, and the details thereof will be explained below.

Generally, photoelectric conversion elements can be classified into charge storage type and non-storage type. The former includes solid-state imaging devices and various photosensitive materials.

The latter is typified by a 7-recon photocell. Of the above photoelectric conversion elements, a charge storage type will be explained below as an example, but non-storage types can also be treated in the same way.

Saturation exposure (I!@S) is generally used to express the sensitivity of a charge storage type photoelectric conversion element. Now 11I under the reference light source and 17 Ke Ix under the test light source
It is assumed that the saturation exposure amount, that is, the photoelectric output of the test photoelectric conversion element is the same at both times. At this time, the output E1 of the illumination meter.
E2 is El under the reference light source: f PT(λ)V(λ)
dλ−・−・=・(1) Under the test light source E = fP0(J)V(λ)dλ−−−−=・(2
). Also, the output E3 of the test photoelectric conversion element. E4 is under the reference light source.E3= f PT(λ)S(λ)dλ...
・・・・・・(3) Under the test light source E4=fP0(λ)S(λ)dλ ・・・・・・
...(4).

■ Here, Po(λ) is the relative spectral distribution of the reference light source.

PT(λ) is the relative spectral distribution of the test light source. Also V(
λ) is the standard luminous efficiency, S(λ) is the relative spectral sensitivity of the test photoelectric conversion element, El and E2 are the illumination meter outputs, and E3 and E4 are the outputs of the test photoelectric conversion element. (1), (2),
(3).

Equation (5) is obtained from equation (4).

Ke f PT(λ)V(λ)dλ f pT(λ
)S(λ)dλfP (λ)■(λ)dλfPo(
λ)S(λ)dλ (5) In equation (5), the spectral distribution P of the reference light source. When (λ) is defined as the standard light source A, Ke becomes a function of PT(λ) and S(λ). This Ke will be referred to as an exposure amount conversion coefficient.

However, the condition is that all four integral values in equation (3) are not zero, that is, that the spectral distribution of the test light source and part of the spectral sensitivity of the test receiver are in the visible wavelength range.
For example, it can be applied to light sources and photoelectric conversion elements of information reading devices such as facsimile machines, electronic copying machines, and optical character reading devices that handle reflective originals.

Based on the above considerations, the value obtained by multiplying the illuminance value on the surface of the photoelectric conversion element by Ke for the test light source corresponds to the illuminance value when the charging conversion element is irradiated with light from standard light source A. be able to.

This theory is based on the idea that if you determine the spectral sensitivity of a photoelectric conversion element, you can easily calculate the spectral sensitivity of the photoelectric conversion element without having to go to the trouble of measuring the photoelectric output of this photoelectric conversion element against light sources with different spectral distributions. By determining the illuminance on the surface and the exposure amount conversion coefficient, the photoelectric output can be determined.

Based on this idea, a method for measuring and quantifying the radiation of a light source will be explained using examples.

FIG. 1 shows a basic configuration diagram of the present invention. The present invention includes a test light source 1, a spectrometer 2, a wavelength-based radiation intensity storage section 3, a test photoelectric conversion element spectral sensitivity storage section 7, a reference light source spectral radiation intensity storage section 8, a photometric amount calculation section 4, a radiation amount calculation section 5. , an exposure amount conversion coefficient calculation section 6, and a display section 9.

Figure 2 shows the inside of the spectrometer 2.
It consists of a photoelectric conversion element whose spectral sensitivity and a are known.

FIG. 3 shows the inside of the wavelength-specific radiant intensity storage unit 3, which is composed of an A/D converter 3a, a spectral radiant intensity calculation circuit 3b, and a memo IJ 3c.

FIG. 4 shows the inside of the photometric amount calculation unit 4, which includes a standard luminous efficiency memo IJ4a and multipliers 4b and 4d.

It consists of adders 4c, 4e, and a divider 4f.

FIG. 6 shows the inside of the radiation amount calculation unit 5, which is composed of multipliers 5a, 6c, adders sb, sd, and a divider 5e.

The radiation from the test light source 1 is separated into wavelengths by a spectrometer 2a in a spectrometer 2, and converted into electrical signals by a photoelectric conversion element 2b. If a plurality of elements set for each unit wavelength are used as the photoelectric conversion element 2b, it is easy to eliminate the need for wavelength feeding of a spectroscope. In this case, the spectrometer 2a can be realized using a continuous interference filter or a diffraction grating type spectrometer, and the photoelectric conversion element 2b can be realized by a one-dimensional solid-state imaging device or the like. This photoelectric output for each unit wavelength is transmitted to the wavelength-specific spectral radiation intensity storage section 3. In the wavelength-specific radiation intensity storage unit 3, A
The /D converter 3a digitizes each unit wavelength, and the spectral radiant intensity calculation circuit 3b stores it in optical form. That is, the spectral radiation intensity of the test light source 1 is stored in the memo IJ3c.

Next, in the photometric quantity calculating section 4, data for each unit wavelength corresponding to the standard luminous efficiency is stored as a digital value in the standard luminous efficiency memory 4a, and the spectral radiant intensity storage section 3 for each wavelength stores data for each unit wavelength corresponding to the standard luminous efficiency.
The data from the reference light source and the data (digital values) from the reference light source spectral radiation intensity storage section 8 are received and multiplied for each unit wavelength. That is, the multiplier 4b multiplies the test light source spectral radiant intensity data from the wavelength-specific spectral radiant intensity storage section 3 and the data from the standard luminous efficiency memo 1J4a for each wavelength. Further, an adder 4c adds the products of each wavelength. As a result, the adder 4c outputs fPo(λ)V(
An output of λ)dλ is obtained. The multiplier 4d multiplies the data from the reference light source spectral radiant intensity storage section 8 and the data from the standard luminous efficiency memory 4a by one digit for each wavelength, and the adder 4e adds the products of each wavelength. As a result, the output fPT(λ)V(λ)dλ is obtained from the adder 4e.

Further, the outputs of the adders 4c and 4e are divided by a divider 4f, and the output from the divider 4f is fPT(λ)(λ)dλ/P0(λ)(λ)dλ. This indicates the illuminance ratio under the reference light source and under the test light source, and is a constant.

Similarly, in the radiation amount calculation unit 6, the multiplier 5a uses the spectral radiation intensity data of the test light source from the wavelength-specific radiation intensity storage unit 3,
The data (digital value) from the test photoelectric conversion element spectral sensitivity storage section 7 is multiplied for each wavelength, and then the adder 6
Add the products of each wavelength at b. As a result, an output of fPo(λ)S(λ)dλ is obtained from the adder 5b. Further, the multiplier 5C multiplies the data from the reference light source spectral radiant intensity storage section 8 and the data from the test photoelectric conversion element spectral sensitivity storage section 7 for each wavelength, and the adder 6d adds the products of each wavelength. do. As a result, an output of f pT(λ)S(λ)dλ is obtained from the adder 5d.

Further, the outputs of adders sb and sd are divided by a divider 5e, and from the divider 5e, fPT(λ)S(λ)dλ/fPo(λ)S(λ)dλ
The following output is obtained. This indicates the output ratio of the test photoelectric conversion element under the reference light source and under the test light source.

Next, the outputs of the photometric amount calculation section 4 and the radiation amount calculation section 5 are sent to the exposure amount conversion coefficient calculation section 6. By determining the output ratio of , the equation (5) is calculated and the exposure amount conversion coefficient Ke is determined.

Furthermore, this result is displayed on the display section 9.

In this way, once the relative spectral distribution of the test photoelectric conversion element is known, the sensitivity coefficient of the photoelectric conversion element with respect to the photometric amount can be easily determined by reading the output of the measuring device for various light sources.

The following two points can be raised as effects obtained by the above device.

(1) Conventionally, the saturation exposure amount for a certain test photoelectric conversion element differed depending on the type of light source. Therefore, the photoelectric output could not be clarified unless both the saturation exposure amount and the name of the light source were listed. Since Ke can already be measured with this device, by simply multiplying the illuminance measurement value by the above Ke, it is possible to make it correspond to the illuminance value when the photoelectric conversion element is irradiated with light from the reference light source (standard light source A). , the relationship between the photometric amount and the photoelectric output is determined systematically.

As a result, for example, for photoelectric conversion elements such as photosensitive materials that require special equipment to measure photoelectric output and are complicated to measure, once the exposure conversion coefficient is determined using the above equipment, the illuminance value can be calculated separately. You can easily measure the photoelectric output and forge it by simply measuring it.

(2) Furthermore, when comparing the photoelectric output of light sources with different spectral distributions for a certain photoelectric conversion element, even if the photoelectric conversion element is not available, the comparison can be easily made even if the spectral sensitivity is different. It also has the advantage of making it easy to compare the photoelectric output when various colored glass filters are inserted into the light source, making it extremely effective for evaluating light sources for information devices and the optical systems of information reading devices. Demonstrate.

In the present invention, it is also possible to input the spectral sensitivity data of the test photoelectric conversion element spectral sensitivity storage section from the outside. Furthermore, although data is treated as digital values in the embodiments of the present invention, similar effects can be obtained with analog values.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the basic configuration of the present invention, Fig. 2 is a block diagram of the spectrometer, Fig. 3 is a block diagram of the wavelength-specific spectral radiant intensity storage section, and Fig. 4 is a block diagram of the photometric quantity calculation section. , Figure 6 is a block diagram of the radiation amount calculation section. 1...Test light source, 2...Spectroscopy device, 2
a...Spectroscope, 2b...Photoelectric conversion element, 3...Spectroscopy by wavelength. Radiation intensity storage unit, 3a...A/D converter, 3b
......Spectral radiant intensity calculation circuit, 3C...
Memory, 4...--Photometric amount calculation section, 6...
・Radiation amount calculation unit, 4a... Standard luminous efficiency memory, ab, 4d = 5a, 5c... Multiplier,
4c, 4e, sb, sd...adder, 4
f, se...Divider, 6...Exposure meter conversion coefficient calculating section, 7...Test photoelectric conversion element spectral sensitivity storage section, 8...Reference light source Spectral radiation intensity storage unit,
9...Display section.

Claims (1)

[Claims] a test light source; a means for spectrally dispersing the amount of radiation of the test light source;
A wavelength-specific spectral radiant intensity storage unit that stores electric signals corresponding to each of the separated wavelengths, a test photoelectric conversion element spectral sensitivity storage unit that stores the spectral sensitivity of the test photoelectric conversion element, and a spectral radiant intensity storage unit that stores the spectral radiant intensity of the reference light source. A reference light source spectral radiant intensity storage unit to be used, and a standard luminous efficiency are stored, and a photometric amount is calculated based on this, the contents of the wavelength-specific spectral radiant intensity storage unit, and the contents of the reference light source spectral radiant intensity storage unit. A radiation amount calculation section that calculates the radiation amount of the test photoelectric conversion element based on the outputs of the photometric amount calculation section, the test photoelectric conversion element spectral sensitivity storage section, the reference light source spectral irradiance storage section, and the outputs of the wavelength-specific spectral irradiance storage section. and an exposure amount conversion factor calculation section that calculates an exposure amount conversion coefficient - from the photometric amount calculation section and the radiation amount calculation section, and calculates the exposure amount conversion coefficient of the test photoelectric conversion element for a light source with an arbitrary spectral distribution. Photoelectric characteristic measuring device d of a photoelectric conversion element characterized by measuring