JPH09325088A - Method and apparatus for measuring luminous intensity of light-emitting semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a luminous intensity with sufficient accuracy, by using an optical power meter for measuring an optical output at a peak wavelength of an emitted light, an optical spectrum analyzer for measuring relative spectral characteristics of a light-emitting semiconductor device, etc. SOLUTION: A light-emitting semiconductor device 1 (LED) is arranged to face a photodetecting part 2. The LED 1 is let to emit light at areas of all operation wavelengths including a peak wavelength. The light is detected at the photodetecting part 2 with a sufficiently small solid angle ω. An optical output of the emitted light is measured by an optical power meter 3, and a relative spectral characteristic by which the peak wavelength of the LED 1 is 1 is measured by an optical spectrum analyzer 6. Then, an output of the optical spectrum analyzer 6 is connected to an operating device 7 to which a relative spectral photosensitivity characteristic and a standard spectral luminous efficiency by which a peak wavelength of the optical power meter 3 is 1 are input, thereby to determine a luminous intensity of the LED 1 through operations. Accordingly, the light-emitting semiconductor device 1 emitting light with a uniform luminous intensity is selected and a highly reliable apparatus is manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photometric technique, and more particularly to a photometric method and a photometric device for a light emitting semiconductor device.

[0002]

2. Description of the Related Art Japanese Industrial Standard JIS7526 defines a standard light source for general-purpose luminous intensity standard bulbs. In the "Light-Emitting Diode Measuring Method" defined in the Japan Electronic Machinery Manufacturers Association (EIAJ) standard ED-4911, the luminous intensity (I) is measured for the purpose of measuring the luminous intensity of the LED under specified conditions.
It is defined to measure v). As shown in FIG. 5, the measuring principle of this measuring method is as follows:
0a and a straight line 22 passing through the center of the light receiving surface 21a of the photometer 21
On the other hand, the standard light source 20 and the photometer 21 are installed so that the light emitting surface 20a and the light receiving surface 21a are perpendicular to each other. Standard light source 2
0 indicates that the luminous intensity is certified according to the provisions of the Measurement Law (JIS752
6) Has been done. The relative spectral sensitivity of the photometer 21 approximates the standard relative luminous efficiency, and the output of the photometer 21 is adjusted so as to be in good proportion to the incident light flux. The photometric distance S between the light center of the standard light source 20 and the light receiving surface 21a of the photometer 21 is equal to the light emitting surface 2
0a or the light-receiving surface 21a, whichever is larger, is 10 times or more the maximum dimension. When the luminous intensity of the standard light source 20 is I _VS and the measurement distance is S _S , the illuminance E _VS on the light receiving surface 21a of the photometer 21 can be obtained from the following equation.

(Equation 3) If the reading of the photometer 21 at this time is i _VS , then E _VS
= Α · i _VS (α is a coefficient) can be used to visually determine the output of the photometer 21. In order to measure the luminous intensity of the light source 20 using this photometric system, the light source 20 and the photometer 21 are properly set, the photometric distance S _T is measured, and the reading i _VS of the photometer 21 is obtained. The luminosity can be calculated.

(Equation 4) When the relative spectral sensitivity of the photometer 21 does not match the standard relative luminous efficiency, P _T (λ) is the spectral distribution of the light source to be measured, P _S (λ) is the spectral distribution of the standard light source 20, and V (λ) is Standard relative luminous efficiency, S
(λ) is the relative spectral sensitivity of the photometer 21, and the reading of the photometer 21 is multiplied by the color correction coefficient k of the following equation.

(Equation 5)

[0003]

As described above, in the conventional photometric method, the photometric standard bulb and the photometric instrument 21 are required, but at present, the Nippon Electric Meters Inspection Center, which is a testing institute in Japan, is required. The standard light bulb for the photometric calibration test is 10C
A luminous body with a luminous intensity of d or more and a small luminous intensity of about 10 mCd is excluded from the calibration test. Further, as shown in FIG. 6, the emission spectrum distribution of the standard light bulb covers a wide band from visible light to infrared light. Also in the photometer 21, there is no one that surely matches the standard relative luminous efficiency V (λ). In a similar manner, when applied to LED (light emitting diode) luminosity measurements, the required LED luminosity is much lower than standard bulbs.
The luminous intensity level is about 0 mCd. Further, the emission spectrum distribution of the LED is narrow and has various peak wavelengths, and complicated color correction is required. However, it is not direct to obtain the standard luminous intensity of the LED with the luminous intensity of the standard light bulb, and a large error occurs. Therefore, it is an object of the present invention to provide a luminous intensity measuring method and a measuring device for a light emitting semiconductor device capable of measuring luminous intensity with sufficient accuracy.

[0004]

A light intensity measuring method for a light emitting semiconductor device according to the present invention comprises a step of disposing a light emitting semiconductor device (1) facing a light receiving portion (2) and a light emitting semiconductor device including a peak wavelength ( The process of causing the light-emitting semiconductor device (1) to emit light over the entire operating wavelength range of 1), the process of receiving the light emitted from the light-emitting semiconductor device (1) by the light receiving unit (2) at a sufficiently small solid angle ω, and the process of receiving light. The process of measuring the optical output P _T of the light emitted by the optical power meter (3) connected to the section (2) and the peak wavelength of the light emitting semiconductor device (1) become 1 by the optical spectrum analyzer (6). Relative spectral characteristic p (λ)
In the process of measuring the optical power meter (3) and the relative spectral light-receiving sensitivity characteristic S (λ) where the peak wavelength of the optical power meter (3) is 1 and the standard relative luminous efficiency characteristic V (λ) are input to the optical spectrum analyzer (6 ) Output p (λ) is connected, and the maximum relative luminous efficiency is Km
As the following formula:

(Equation 6) And determining the luminous intensity Iv of the light emitting semiconductor device. A photometric device for a light emitting semiconductor device according to the present invention supplies a current to the light emitting semiconductor device (1) to cause the light emitting semiconductor device (1) to emit light in the entire operating wavelength region including the peak wavelength. A power supply circuit (8), a light receiving section (2) arranged to face the light emitting semiconductor device (1) and receiving light emitted from the light emitting semiconductor device (1) at a sufficiently small solid angle ω; The relative spectral characteristic p of the optical power meter (3) connected to 2) and measuring the optical output P _T at the peak wavelength of the emitted light, and the light emitting semiconductor device (1).
An optical spectrum analyzer (6) for measuring (λ) and an arithmetic unit (7) connected to the optical power meter (3) and the optical spectrum analyzer (6) are provided. An optical spectrum analyzer (6) to which the relative spectral light receiving sensitivity characteristic S (λ) and the standard relative luminous efficiency characteristic V (λ) of the optical power meter (3) are input.
The output p (λ) of is connected, and the maximum relative luminous efficiency is Km.

(Equation 7) Is calculated to determine the luminous intensity Iv of the light emitting semiconductor device.

In this way, the relative spectral characteristic p (λ) of the light emitting semiconductor device (1) is measured by the optical spectrum analyzer (6).
And the luminous intensity of the light emitting semiconductor device (1) can be accurately and easily measured by the relative spectral light receiving sensitivity characteristic S (λ) and the standard relative luminous efficiency characteristic V (λ) of the optical power meter (3). If all of the measuring instruments used are measured by a calibration test measuring device at a Japanese inspection agency, the luminous intensity standard of the luminous semiconductor device (1) can be obtained with sufficient accuracy. In addition, the luminous intensity values obtained from the measuring device calibrated only by the measuring instruments that are all calibrated and tested have been calibrated (traceability).

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a luminous intensity measuring method and a measuring device of a light emitting semiconductor device according to the present invention applied to a visible light emitting diode will be described below with reference to FIGS. As shown in FIG. 1, an LED 1 as a light emitting semiconductor device arranged in a dark box 5 is subjected to a standard calibration test on a power supply circuit 8
The light of the LED 1 is received by the light receiving section 2. The solid angle ω of the light emitted from the LED 1 to the light receiving unit 2 is ω = 0.001 sr. The amount of light received by the light receiving unit 2 is displayed on the optical power meter 3. Further, the light of the LED 1 is supplied to the optical spectrum analyzer 6 via the optical fiber 4, the output of the optical spectrum analyzer 6 is given to the arithmetic unit 7, and the numerical values of the optical power meter 3 and the optical spectrum analyzer 6 are calculated by the arithmetic unit 7. Use and calculate. As the light intensity measuring method of the light emitting semiconductor device according to the present invention, a method of measuring without using a standard light bulb was tried. The photometric distance has a solid angle of 0.00
The distance is set to 1 sr and the luminous intensity is converted from the emission intensity of the LED 1. k is the optical output at the peak wavelength, p
(Λ) relative spectral characteristics (1 at peak wavelength), measured LED
When the absolute spectral characteristic of 1 is P (λ), the following equation holds.

[0007]

(Equation 8)

As shown in FIG. 2, the brightness of the LED 1 at the wavelength λ is obtained by multiplying the area obtained by multiplying P (λ) by the minute wavelength length by the relative spectral light receiving sensitivity S (λ) at the wavelength λ. 3 shows the change in the light receiving sensitivity S (λ) with respect to the change in the wavelength of light. Therefore, the optical power meter 3 with the light receiving sensitivity S (λ)
The light output P _T of the LED 1 measured in step 1 is expressed by the following equation.

[0009]

[Equation 9]

Here, when P (λ) in Expression 9 is converted from Expression 8, the following expression is obtained.

[0011]

(Equation 10)

Since k is a constant, the following equation is obtained.

[0013]

[Equation 11]

The following equation can be obtained by expressing the equation 11 with respect to k.

[0015]

(Equation 12)

Substituting k in Equation 12 into Equation 8 gives the following equation.

[0017]

(Equation 13)

On the other hand, the luminous flux Φv of the LED 1 is represented by the following equation by the maximum specific luminous efficiency Km and the standard specific luminous efficiency V (λ) shown in FIG.

[0019]

[Equation 14]

Here, the following expression is obtained by converting into P (λ) from Expression 9.

[0021]

(Equation 15)

P _T is a photometric value constant, which can be rearranged into the following equation.

[0023]

(Equation 16)

Since the light receiving condition of this photometric system is the solid angle ω, the luminous intensity Iv of the LED 1 is expressed by the following equation.

[0025]

[Equation 17]

Therefore, the following equation is obtained.

[0027]

(Equation 18)

The luminous intensity Iv of the equation 18 is the maximum specific luminous efficiency Km.
The product of the LED1 of the light output P _T, the relative spectral characteristic p
The integral value (L) obtained by integrating the product of (λ) and the standard relative luminous efficiency V (λ) with respect to wavelength, the integral value obtained by integrating the product of the relative spectral characteristic p (λ) and the light receiving sensitivity S (λ) with respect to wavelength. It is the value obtained by multiplying by the value divided by and dividing by the solid angle ω. The maximum specific luminous efficiency Km, which is a coefficient that links the radiation amount and the photometric amount, is Km =
683 (lm / w), 11mcd standard LED
An example of the actual measurement value of is shown below.

[0029]

[Equation 19]

Embodiments of the present invention provide the following advantages. 1. The relative spectral characteristic p (λ) of the light emitting semiconductor device can be measured by an optical spectrum analyzer, and the luminous intensity of the light emitting semiconductor device can be accurately and easily measured by the relative spectral light receiving sensitivity S (λ) of the optical power meter. 2 Do not use a standard bulb as a photometer with a standard relative luminous efficiency V (λ) filter. 3. If all the measuring instruments used are measured by a calibration test measuring device at a Japanese inspection agency, the luminous intensity standard of the luminous semiconductor device can be obtained with sufficient accuracy. 4 In addition, the luminous intensity values obtained from the measuring device calibrated only by the measuring instruments that are all calibrated and tested have been calibrated (traceability).

[0031]

According to the present invention, it is possible to easily detect the luminous intensity of the light emitting semiconductor device and select the light emitting semiconductor device which emits light with a uniform luminous intensity. Therefore, a highly reliable device can be manufactured using the light emitting semiconductor device. Also,
It is possible to easily calculate the luminous intensity standard value of the light emitting semiconductor device by using a commercially available optical measuring instrument that has been subjected to the calibration test, and display the luminous intensity value of the light emitting semiconductor device subjected to the calibration test.

[Brief description of drawings]

FIG. 1 is a schematic view of an LED photometric device according to the present invention.

FIG. 2 is a graph showing the relationship between the wavelength of light and the spectral density of radiant flux.

FIG. 3 is a graph showing changes in photosensitivity with respect to changes in wavelength of light.

FIG. 4 is a graph showing the relationship between the wavelength of light and standard luminous efficiency.

FIG. 5 is a schematic diagram of a conventional photometric device for measuring the luminous intensity of an LED using a standard light source.

FIG. 6 is a graph showing emission spectrum distributions of a standard light bulb and an LED.

[Explanation of symbols]

1 ... LED, 2 ... Light receiving part, 3 ... Optical power meter, 4 ... Optical fiber, 5 ... Dark box, 6 ...
・ Optical spectrum analyzer, 7 ・ ・ Calculator,

Claims (2)

[Claims] 1. A process of disposing a light emitting semiconductor device facing a light receiving part, a process of causing the light emitting semiconductor device to emit light in the entire operation wavelength region of the light emitting semiconductor device including a peak wavelength, and irradiation from the light emitting semiconductor device. The received light with a sufficiently small solid angle ω by the light receiving unit, the process of measuring the optical output P _T of the light emitted by the optical power meter connected to the light receiving unit, and the optical spectrum analyzer The process of measuring the relative spectral characteristic p (λ) at which the peak wavelength of the light emitting semiconductor device is 1, and the relative spectral light receiving sensitivity characteristic S (λ) and the standard relative luminous efficiency characteristic V at which the peak wavelength of the optical power meter is 1. The output p (λ) of the optical spectrum analyzer is input to the arithmetic unit to which (λ) is input.
, And the maximum relative luminous efficiency is Km. And the step of determining the luminous intensity Iv of the light emitting semiconductor device according to the above method. 2. A power supply circuit for supplying a current to the light emitting semiconductor device to cause the light emitting semiconductor device to emit light in the entire operating wavelength region of the light emitting semiconductor device including a peak wavelength, and a power supply circuit arranged to face the light emitting semiconductor device. Further, a light receiving portion for receiving the light emitted from the light emitting semiconductor device at a sufficiently small solid angle ω, and an optical power meter connected to the light receiving portion for measuring an optical output P _T at the peak wavelength of the emitted light. And an optical spectrum analyzer for measuring a relative spectral characteristic p (λ) of the light emitting semiconductor device, and an arithmetic unit connected to the optical power meter and the optical spectrum analyzer. The output p (λ) of the optical spectrum analyzer is connected to a calculator into which the characteristic S (λ) and the standard relative luminous efficiency characteristic V (λ) are input, and the maximum relative luminous efficiency is set to Km. The light intensity measuring device for a light emitting semiconductor device, wherein the light intensity Iv of the light emitting semiconductor device is determined by performing the above calculation.