JP2011107114A - Photometric device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photometric device capable of calibrating in a short time without requiring repetition of sensitivity calibration in each wavelength of each optical sensor, even when a spectral sensitivity characteristic is changed with elapse of time, and measuring highly accurately characteristics such as chromaticity, illuminance or color rendering properties of light to be tested. <P>SOLUTION: An optical sensor means 11 including an optical filter and a light receiving element is constituted by arraying a plurality of optical sensors SE having each different spectral sensitivity characteristic whose sensitivity wavelength domain is restricted respectively. A control means 103 performs weighting by using a fixed weighting coefficient corresponding to the spectral sensitivity characteristic of each different optical sensor SE, multiplies the weighting coefficient by a prescribed correction coefficient, and changes the sensitivity characteristic of the optical sensor means 11 into a prescribed characteristic in a wavelength domain in a prescribed range. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an object to be measured such as chromaticity, illuminance, color rendering property, wavelength, power, etc. of a fluorescent lamp, a light bulb, an LED illumination, an LED element, an LD, an LCD (liquid crystal display), etc., which are light sources to be measured (light under test). The present invention relates to a photometric device for measuring the characteristics of test light.

  Conventionally, various devices have been proposed as photometric devices that measure the characteristics of light from a measurement target light source such as a fluorescent lamp, a light bulb, and an LED element.

  For example, as shown in FIG. 11 attached to the present application, the photometric device described in Patent Document 1 receives n pieces of photoelectric conversion element groups 211 to 211 that receive measurement light and output received light signals corresponding to n wavelengths. 214, 221-224. The received light signals output from the photoelectric conversion element groups 211 to 214 and 221 to 224 are converted into digital signals by the A / D converter 31 and input to the CPU 35. The RAM 32 temporarily stores received light signals and the like, and the ROM 33 stores a control program of the CPU 35, and stores a weighting coefficient for approximating the color matching function as the control program.

  Therefore, the photometric device disclosed in Patent Document 1 has a color matching function defined by the International Commission on Illumination (abbreviated as CIE) using the received light signal stored in the RAM 32 and the weighting coefficient stored in the ROM 33 with the above configuration. An apparatus having output characteristics approximate to x (λ), y (λ), z (λ) is realized, and approximate color matching functions x ′ (λ), y ′ (λ), Based on the output value of z ′ (λ), the tristimulus values X, Y and Z can be calculated, and the characteristics of the measurement light can be measured.

JP 2002-13981 A

  However, the spectral sensitivity characteristics of the n photoelectric conversion element groups 211 to 214 and 221 to 224 of the photometric device as described in Patent Document 1 above, that is, the photoelectric conversion means (photosensors) change from the time of device calibration over time. (That is, it may deteriorate).

  Here, in FIG. 12 attached to the present application, S1 (λ), S2 (λ), S3 (λ),... Sn (λ) indicate spectral sensitivity characteristics at the time of device calibration. It is assumed that '(λ), S2' (λ), S3 '(λ), ... Sn' (λ) are spectral sensitivity characteristics after change with time.

  The tristimulus value X used for calculating the weighting coefficient due to changes over time, that is, when the spectral sensitivity characteristics at the time of device calibration are different, the output of each photosensor is different, and is calculated together with the weighting coefficient. , Y, and Z change, resulting in a measurement error.

  Therefore, it is necessary to recalibrate the sensitivity for each wavelength of each photosensor of the photometric device. This operation is extremely complicated and takes a long time. Further, a wavelength variable monochromatic light source is required for sensitivity correction.

  The above problem also occurs when the photometric device has different sensitivity characteristics due to a difference from the reference measuring instrument owned by the user.

  Therefore, even if the spectral sensitivity characteristic changes with time, the object of the present invention is not to recalibrate the sensitivity for each wavelength of each photosensor, it can be calibrated in a short time, and the test can be performed with high accuracy. To provide a photometric device capable of measuring characteristics such as chromaticity, illuminance, and color rendering properties of light with high accuracy.

  Another object of the present invention is that it is not necessary to recalibrate the sensitivity for each wavelength of each sensor even when the photometric device exhibits different characteristics due to the difference from the reference measuring instrument owned by the user, and for a short time. To provide a photometric device that can reduce the difference from the reference measuring instrument and can measure the chromaticity, illuminance, color rendering, etc. of the light under test with high accuracy. It is.

The above object is achieved by a photometric device according to the present invention. In summary, the present invention has a sensitivity characteristic in a wavelength range of a predetermined range, and includes a detection unit including an optical sensor unit that receives light under test from a light source to be measured, and a light reception signal from the detection unit. In a photometric device equipped with a measuring unit for determining the characteristics of a light source to be measured,
The optical sensor means includes an optical filter and a light receiving element, and is configured by arranging a plurality of optical sensors each having a different spectral sensitivity characteristic in which a sensitivity wavelength region is limited,
The measuring unit performs weighting using a predetermined weighting coefficient corresponding to the spectral sensitivity characteristics of the different optical sensors, and multiplies the weighting coefficient by a predetermined correction coefficient to obtain sensitivity of the optical sensor means. It is a photometric device characterized by having a control means for changing the characteristic to a predetermined characteristic in the wavelength range of the predetermined range.

  According to an embodiment of the present invention, the detection unit includes a housing in which the optical sensor means is installed, and the housing is provided with an incident portion opening through which light to be tested is incident. A diffusion plate is installed in the entrance opening.

  According to another embodiment of the present invention, the control unit of the measurement unit includes an I / V conversion amplifier that converts a current signal, which is a light reception signal from the optical sensor unit, into a voltage, and the I / V conversion amplifier. An A / D converter for converting the received light signal into a digital value, first storage means for storing the received light signal converted by the A / D converter, and a first storage for storing the weighting coefficient and the correction coefficient. Two storage means.

According to another embodiment of the present invention, the sensitivity characteristic of each photosensor is determined using the received light signal stored in the first storage unit and the weighting coefficient stored in the second storage unit. By weighting and adding, the spectral sensitivity characteristic of the combined photosensor is made a predetermined characteristic for a wavelength range of a predetermined range,
When the spectral sensitivity characteristic of each photosensor changes, the weighting coefficient of each photosensor is multiplied by the correction coefficient determined by the rate of change of the spectral sensitivity characteristic of each photosensor and added. Thus, the spectral sensitivity characteristic of the combined optical sensor is set to a predetermined characteristic with respect to a predetermined wavelength range.

According to another embodiment of the present invention, a sensitivity characteristic of each photosensor is obtained using the light reception signal stored in the first storage unit and the weighting coefficient stored in the second storage unit. By weighting and adding, the spectral sensitivity characteristic of the photosensor after addition is made a predetermined characteristic for a wavelength range of a predetermined range,
In order to reduce the difference from the reference measuring instrument possessed by the user, the ratio of the spectral sensitivity characteristics of the photometric device to the reference spectrum of the reference measuring instrument and the true value spectrum of the reference light source used for the reference measuring instrument The correction coefficient determined in this way is multiplied by the weighting coefficient of each optical sensor, and added to make the spectral sensitivity characteristic of the combined optical sensor a predetermined characteristic with respect to a predetermined wavelength range.

According to another embodiment of the present invention, a sensitivity characteristic of each photosensor is obtained using the light reception signal stored in the first storage unit and the weighting coefficient stored in the second storage unit. By weighting and adding, the spectral sensitivity characteristic of the photosensor after addition is made a predetermined characteristic for a wavelength range of a predetermined range,
In order to reduce the difference from the reference measuring instrument that the user has, the correction coefficient determined by the variation ratio of the spectral sensitivity characteristic of the photometric device due to the difference in wavelength accuracy of the reference measuring instrument By multiplying and adding the weighting coefficient of the sensor, the spectral sensitivity characteristic of the optical sensor after the summation is made a predetermined characteristic for a wavelength range within a predetermined range.

  According to the present invention, even if the spectral sensitivity characteristic changes with time, it is not necessary to recalibrate the sensitivity of each optical sensor for each wavelength, and calibration can be performed in a short time, and the light under test can be accurately detected. It is possible to measure characteristics such as chromaticity, illuminance, and color rendering with high accuracy.

  Further, according to the present invention, it is not necessary to recalibrate the sensitivity of each sensor for each wavelength even when the photometric device exhibits different characteristics due to the difference from the reference measuring instrument owned by the user, and the time is short. The difference from the reference measuring instrument can be reduced, and the chromaticity, illuminance, color rendering, etc. of the light under test can be measured with high accuracy.

  The present invention does not require a wavelength tunable monochromatic light source for calibration, and is very convenient and highly useful.

It is a block diagram which shows the electrical constitution of one Example of the photometry apparatus which concerns on this invention. It is a schematic block diagram of one Example of the detection part of the photometry apparatus which concerns on this invention. It is a figure which shows the relative spectral sensitivity characteristic of each optical sensor which comprises an optical sensor means. It is a figure which shows a color matching function. It is a figure which shows a color matching function and an approximate color matching function. It is a figure which shows the relative spectral sensitivity characteristic after the total of each optical sensor which comprises an optical sensor means. It is a figure explaining the difference of the relative spectral sensitivity characteristic after the total of each optical sensor which comprises an optical sensor means by the difference between photometry apparatuses. It is a figure explaining the influence on the spectral sensitivity characteristic of one sensor of a plurality of sensors by wavelength accuracy gap. It is a figure explaining the influence on the spectral sensitivity characteristic in a some sensor by wavelength accuracy gap. It is a figure explaining the linear interpolation for correct | amending a wavelength precision shift. It is a block diagram which shows the electrical structure of an example of the conventional photometry apparatus. It is a figure explaining the change of the spectral sensitivity characteristic of each photosensor which comprises a photosensor means.

  Hereinafter, the photometric device according to the present invention will be described in more detail with reference to the drawings.

Example 1
An embodiment of the photometric device 1 according to the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing an embodiment of the electrical configuration of the photometric device 1 in this embodiment, and FIG. 2 shows the configuration of an embodiment of the detection unit 10 including the optical sensor means 11.

  According to the present embodiment, the photometric device 1 includes a detection unit 10 and a measurement unit 100. The detection unit 10 has a housing (casing) 12 in which an optical sensor means 11 is installed. In this embodiment, the detection unit 10 is located on the left side and receives light (light under test) from a light source to be measured. An incident portion opening 13 is provided. A diffusion plate 14 is installed in the entrance opening 13. The operation of the diffusion plate 14 will be described later.

  The optical sensor means 11 disposed inside the casing 12 is provided with a plurality of optical sensors SE (SE1, SE2, SE3,...) In order to detect light diffused by the diffusion plate 14 from the entrance opening 13. SEn-2, SEn-1, SEn). Each optical sensor SE includes an optical filter f (f1, f2, f3,... Fn-2, fn-1, fn) and a light receiving element (photoelectric conversion element) PD (PD1, PD2, PD3,... PDn-2, PDn-1, PDn), and each optical sensor SE has a limited sensitivity wavelength region.

  That is, according to the present invention, each of the individual optical sensors SE1, SE2, SE3,... SEn-2, SEn-1, SEn constituting the optical sensor means 11 is shown in FIG. Spectral sensitivity characteristics S1 (λ), S2 (λ), S3 (λ),... Sn-2 (λ), Sn-1 (λ), Sn (λ). That is, the spectral sensitivity characteristics S1 (λ), S2 (λ), S3 (λ),..., Sn-2 (λ), Sn-1 (λ), and Sn (λ) of each optical sensor SE are bands. Has the characteristics of a path. The spectral sensitivity characteristic S (λ) of each optical sensor SE is obtained by measuring each optical sensor using a spectroscopic means after the optical sensor SE is incorporated in the photometric device. This spectral sensitivity characteristic S (λ) is stored in the ROM 105.

  Accordingly, a wavelength range that is a predetermined range of the optical sensor means 11 in the plurality of optical sensors SE1, SE2, SE3,... SEn-2, SEn-1, SEn, for example, a detection wavelength of 380 to 720 nm. It constitutes an area.

  Referring to FIG. 1, in this embodiment, the photometric device 1 includes a plurality of optical sensors SE (SE1, SE2, SE3,... SEn-2, SEn-1, SEn) that constitute the detection unit 10. A light reception signal (current signal) of the optical sensor means 11 is transmitted to the measurement unit 100. The measurement unit 100 includes an I / V conversion amplifier 101 that converts a light reception signal (current signal) into a voltage, an A / D converter 102 that converts a light reception signal from the I / V conversion amplifier 101 into a digital value, A control means (CPU) 103 that receives the light reception signal converted by the D converter 102 is provided, and the optical power and the like can be calculated and displayed on the display means 106.

  According to the present embodiment, the control unit 103 stores the light reception signal transmitted from the A / D converter 102 in the RAM (first storage unit) 104, the light reception signal stored in the RAM 104, and Using a predetermined weighting coefficient stored in a ROM (second storage means) 105, weighting is performed corresponding to the spectral sensitivity characteristic S (λ) of each photosensor SE, and the addition is performed. Thereby, the spectral sensitivity characteristic of the optical sensor means 11 after the addition can be set to a predetermined characteristic with respect to a predetermined wavelength range.

  That is, the color matching function x ′ approximated to the color matching functions x (λ), y (λ), and z (λ) using the received light signal stored in the RAM 104 and the weighting coefficient stored in the ROM 105. (Λ), y ′ (λ), z ′ (λ) are obtained, and tristimulus values X, Y, Z based on the approximate color matching function can be calculated.

  FIG. 4 shows color matching functions x (λ), y (λ), z (λ), and FIG. 5 shows color matching functions x (λ), y (λ), z (λ), and color matching functions. Approximated approximate color matching functions x ′ (λ), y ′ (λ), z ′ (λ) are shown.

The approximate color matching functions x ′ (λ), y ′ (λ), and z ′ (λ) can be expressed by the following equations.
x ′ (λ) = a1 × S1 (λ) + a2 × S2 (λ) +... + an × Sn (λ)
y ′ (λ) = b1 × S1 (λ) + b2 × S2 (λ) +... + bn × Sn (λ)
z ′ (λ) = c1 × S1 (λ) + c2 × S2 (λ) +... + cn × Sn (λ)
Here, a1 to an, b1 to bn, and c1 to cn are weighting coefficients stored in the ROM 105.

  Based on the tristimulus values X, Y, and Z obtained above, the control means 103 measures the light source characteristics such as the chromaticity, illuminance, and color rendering properties of the light source to be measured (light under test). Can be calculated.

  The step of obtaining the approximate color matching function and the step of obtaining the tristimulus value from the approximate color matching function are described in, for example, the above-mentioned Patent Document 2 and are well known to those skilled in the art. Description is omitted.

  As another method, as can be understood from the above, according to the photometric device 1 of the present embodiment having the above-described configuration, a weighted addition is performed corresponding to the spectral sensitivity S (λ) of each photosensor SE. Is done. Therefore, the spectral sensitivity characteristic of the optical sensor means 11 after the summation can be, for example, a linear characteristic with respect to a predetermined wavelength range.

That is, the spectral sensitivity characteristic SΣ (λ) of the optical sensor means 11 after the addition is
SΣ (λ) = k1 · S1 (λ) + k2 · S2 (λ) +... + KnSn (λ)
It is represented by k1 to kn are weighting coefficients.

  The spectral sensitivity characteristic SΣ (λ) of the optical sensor means 11 after the addition can be linear, for example, flat, as shown in FIG. 6, with respect to a predetermined wavelength range.

  In the present embodiment, the photometric device 1 has 16 optical sensors SE as the optical sensor means 11. Each optical sensor SE used a silicon photodiode as the light receiving element PD. FIG. 3 shows spectral sensitivity characteristics S1 (λ), S2 (λ), S3 (λ),... S16 (λ) (n = 16) of each optical sensor SE in the present embodiment.

  That is, according to the present embodiment, the optical sensor means 11 including 16 optical sensors SE outputs 16 received light signals having peaks at a pitch of 20 nm from 380 nm to 720 nm as shown in FIG. Note that the number of the optical sensors SE is not limited to 16, and other numbers may be used as desired.

  As described above, in this embodiment, the diffusion plate 14 is installed in the incident portion opening 13 of the casing 12. The operation of the diffusion plate 14 will be described.

  When the incident angle (θ) at which the light under test enters the detector 10 changes extremely, the light distribution is biased.

  According to the present invention, as described above, the optical sensor means 11 includes a plurality of optical sensors SE1, SE2,... SEn having different transmission wavelengths. Therefore, when the incident angle (θ) of the light to be tested to the detection unit 10 changes drastically and the light distribution is biased, a plurality of optical sensors SE1, SE2,. -The light quantity on SEn changes and the measured value changes.

  Therefore, in this embodiment, the diffusion plate 14 is fixed to the incident part opening 13 so as to cover the entire area of the incident part opening 13. As the diffusion plate 14, an opal type diffusion plate (trade name: manufactured by Sigma Koki Co., Ltd.) is preferably used.

  Therefore, according to the photometric device 1 of this embodiment, it is possible to measure the power and chromaticity of the light under test with high accuracy even when the incident angle of the light under test changes.

  Even in the photometric device 1 configured as described above, the sensitivity characteristics of the light receiving elements (photoelectric conversion elements) PD (PD1, PD2, PD3,..., PDn-2, PDn-1, PDn) constituting the optical sensor SE are high. The sensitivity characteristics at the time of device calibration may change (deteriorate) over time.

  FIG. 3 shows the spectral sensitivity characteristics S1 (λ), S2 (λ), S3 (λ),. '(Λ), S3' (λ),... Sn '(λ).

  If the photometric device is used in this state, the output of each sensor SE will be different, for example, the tristimulus values X, Y, and Z calculated together with the weighting coefficient will change, resulting in a measurement error.

  Therefore, it is necessary to recalibrate the sensitivity for each wavelength of each sensor SE of the photometric device. This operation is extremely complicated. Therefore, the photometric device 1 of the present embodiment has the following correction function.

  A light source for correcting the photometric device 1 is selected, and the selected light source is measured by a calibrated reference measuring instrument such as a spectrophotometer. In this embodiment, a light bulb is selected as the light source. FIG. 3 shows the spectrum (spectral data) P (λ) of this light source bulb.

First, spectral data (spectrum P (λ)) of the light source bulb and spectral sensitivity characteristics S1 (λ), S2 (λ), S3 (λ) at the time of calibration of the photometric device 1 stored in the ROM 105 of the photometric device 1 ),..., Sn (λ) from each light receiving element (photoelectric conversion element) PD (PD1, PD2, PD3,..., PDn-2, PDn-1, PDn), that is, The output (prediction) from each optical sensor SE (SE1, SE2, SE3,... SEn-2, SEn-1, SEn) is calculated and obtained. That means
SE1 output (prediction) = P (λ1) x S1 (λ1) + P (λ2) x S1 (λ2) + ... + P (λn) x S1 (λn)
SE2 output (prediction) = P (λ1) x S2 (λ1) + P (λ2) x S2 (λ2) + ... + P (λn) x S2 (λn)
...
SEn output (prediction) = P (λ1) × Sn (λ1) + P (λ2) × Sn (λ2) + ··· + P (λn) × Sn (λn)
It is.

Next, using a light source bulb having the spectral data (spectrum) P (λ), current spectral sensitivity characteristics S1 ′ (λ), S2 ′ (λ), S3 ′ (λ),. The output from each optical sensor SE in the photometric device having '(λ) is actually measured and obtained. That means
SE1 output (measurement) = P (λ1) × S1 '(λ1) + P (λ2) × S1' (λ2) + ... + P (λn) × S1 '(λn)
SE2 output (measurement) = P (λ1) × S2 '(λ1) + P (λ2) × S2' (λ2) + ... + P (λn) × S2 '(λn)
...
SEn output (measurement) = P (λ1) x Sn '(λ1) + P (λ2) x Sn' (λ2) + ... + P (λn) x Sn '(λn)
It is.

Here, the ratio between the output (predicted) value of each optical sensor SE obtained as described above and the output (measured) value, that is, the fluctuation ratio is taken, and the correction values B1, B2,...・ Bn. That is,
B1 = SE1 output (prediction) / SE1 output (measurement)
B2 = SE2 output (prediction) / SE2 output (measurement)
...
Bn = SEn output (prediction) / SEn output (measurement)
It is.

  The ratios B1, B2,... Bn are stored in the ROM 105 of the photometric device 1 as correction values (correction coefficients) determined by the variation ratio of the spectral sensitivity characteristics of each optical sensor SE. And it can be used at the time of calibration of the photometry device 1, and the error factor by deterioration of sensor sensitivity can be reduced.

  That is, for example, if the photometric device of the present invention is used, the tristimulus values are based on the output values of the approximate color matching functions x ′ (λ), y ′ (λ), z ′ (λ) obtained by this device. X, Y, and Z can be calculated and the characteristics of the measurement light can be measured.

At the time of device calibration at this time, as described above, the approximate color matching functions x ′ (λ), y ′ (λ), and z ′ (λ) are expressed by the following equations.
x ′ (λ) = a1 × S1 (λ) + a2 × S2 (λ) +... + an × Sn (λ)
y ′ (λ) = b1 × S1 (λ) + b2 × S2 (λ) +... + bn × Sn (λ)
z ′ (λ) = c1 × S1 (λ) + c2 × S2 (λ) +... + cn × Sn (λ)
Here, a1 to an, b1 to bn, and c1 to cn are weighting coefficients stored in the ROM 105.

Therefore, in this embodiment, the weighting coefficients are further multiplied by correction coefficients B1 to Bn stored in the ROM 105 for correcting sensor sensitivity deterioration. That means
x ′ (λ) = B1 × a1 × S1 (λ) + B2 × a2 × S2 (λ) +... + Bn × an × Sn (λ)
y ′ (λ) = B1 × b1 × S1 (λ) + B2 × b2 × S2 (λ) +... + Bn × bn × Sn (λ)
z ′ (λ) = B1 × c1 × S1 (λ) + B2 × c2 × S2 (λ) +... + Bn × cn × Sn (λ)
It is said.

  According to the present embodiment, as described above, correction coefficients B1 to Bn for correcting sensor sensitivity deterioration are stored in the ROM 105 of the apparatus, and the correction coefficients are weighted coefficients a1 to an, b1 to bn, and c1 to cn. Sensor sensitivity correction can be achieved by multiplying by.

  As described above, according to the present invention, even if the spectral sensitivity characteristics change with time, it is not necessary to recalibrate the sensitivity for each wavelength of each sensor, and calibration can be performed in a short time with high accuracy. It is possible to measure the chromaticity and illuminance of the light under test with high accuracy.

  Further, the present invention does not require a wavelength variable monochromatic light source for calibration, and is very convenient and highly useful.

Example 2
In the first embodiment, the case has been described in which the photometric device 1 has a correction function for reducing the error factor when the sensitivity characteristic changes with time and the output of each sensor fluctuates.

  Even if the sensor sensitivity does not change with time as in the first embodiment, the present invention provides a reference measuring instrument for calibration of a device held by the manufacturer of the photometric device, that is, a reference measurement used when manufacturing the photometric device. There may be a difference between the measuring instrument and a reference measuring instrument held by a user who uses the photometric device. For example, the spectrum of the reference measuring instrument owned by the user may be different from the true value spectrum.

  FIG. 7 shows an example of the relationship among the reference spectrum (user spectrum) PA, the true value spectrum P, and the spectral sensitivity characteristic S (λ) of the photometric device by the reference measuring instrument used by the user.

  The true value spectrum P is a spectrum of a light source (spectrum spectrophotometer) when a reference light source (for example, a reference white LED) of a reference measuring device used by a user is measured by another reference measuring device in which calibration is performed, for example, a spectrophotometer. Data). In the present embodiment, the reference spectrum PA and the true value spectrum P are shown as straight lines for easy understanding, but are not limited thereto.

The spectral sensitivity characteristics S1 (λ), S2 (λ), S3 (λ),... Sn (λ) stored in the ROM 105 of the photometric device at the time of calibration are used for the reference spectrum PA. The output (prediction) from each optical sensor SE is calculated and obtained. That means
SE1 output (prediction) = PA (λ1) x S1 (λ1) + PA (λ2) x S1 (λ2) + ... + PA (λn) x S1 (λn)
SE2 output (prediction) = PA (λ1) x S2 (λ1) + PA (λ2) x S2 (λ2) + ... + PA (λn) x S2 (λn)
...
SEn output (prediction) = PA (λ1) x Sn (λ1) + PA (λ2) x Sn (λ2) + ... + PA (λn) x Sn (λn)
It is.

Next, using a light source (reference white LED) having the true spectrum P, photometry having spectral sensitivity characteristics S1 (λ), S2 (λ), S3 (λ),... Sn (λ) The output from each optical sensor SE in the apparatus is actually measured and obtained. That means
SE1 output (measurement) = P (λ1) x S1 (λ1) + P (λ2) x S1 (λ2) + ... + P (λn) x S1 (λn)
SE2 output (measurement) = P (λ1) x S2 (λ1) + P (λ2) x S2 (λ2) + ... + P (λn) x S2 (λn)
...
SEn output (measurement) = P (λ1) × Sn (λ1) + P (λ2) × Sn (λ2) + ··· + P (λn) × Sn (λn)
It is.

Here, the output (predicted) value and the output (measured) value of each optical sensor SE (SE1, SE2, SE3,... SEn-2, SEn-1, SEn) obtained as described above Ratio, i.e., the rate of variation, is taken as correction values (correction coefficients) C1, C2,. That is,
C1 = SE1 output (prediction) / SE1 output (measurement)
C2 = SE2 output (prediction) / SE2 output (measurement)
...
Cn = SEn output (prediction) / SEn output (measurement)
It is.

  The above-mentioned ratios C1, C2,... Cn correct the fluctuation rate of the spectral sensitivity characteristic of the photometric device caused by the fact that the reference spectrum of the user's reference measuring device is different from the true value spectrum, and the user's reference measurement Is stored in the ROM 105 of the photometric device 1 as a correction coefficient for reducing the difference from the instrument. And it is used at the time of the measurement by a photometry apparatus, and the error factor by the difference of a reference measuring device can be reduced.

  That is, for example, if the photometric device 1 of the present embodiment is used, three based on the output values of the approximate color matching functions x ′ (λ), y ′ (λ), z ′ (λ) obtained by this device. Stimulus values X, Y, and Z can be calculated and the characteristics of the measurement light can be measured.

At the time of device calibration at this time, as described above, the approximate color matching functions x ′ (λ), y ′ (λ), and z ′ (λ) are expressed by the following equations.
x ′ (λ) = a1 × S1 (λ) + a2 × S2 (λ) +... + an × Sn (λ)
y ′ (λ) = b1 × S1 (λ) + b2 × S2 (λ) +... + bn × Sn (λ)
z ′ (λ) = c1 × S1 (λ) + c2 × S2 (λ) +... + cn × Sn (λ)
Here, a1 to an, b1 to bn, and c1 to cn are weighting coefficients stored in the ROM 105.

Therefore, in this embodiment, the weighting coefficients are further multiplied by correction coefficients C1 to Cn based on the difference between the reference measuring instruments stored in the ROM 105. That means
x ′ (λ) = C1 × a1 × S1 (λ) + C2 × a2 × S2 (λ) +... + Cn × an × Sn (λ)
y ′ (λ) = C1 × b1 × S1 (λ) + C2 × b2 × S2 (λ) +... + Cn × bn × Sn (λ)
z ′ (λ) = C1 × c1 × S1 (λ) + C2 × c2 × S2 (λ) +... + Cn × cn × Sn (λ)
It is said.

  According to the present embodiment, as described above, the correction coefficients C1 to Cn for correcting the characteristics of the photometric device due to the difference from the reference measuring instrument owned by the user are stored in the ROM 105 of the device, and this correction value is stored. Is multiplied by the weighting coefficients a1 to an, b1 to bn, and c1 to cn, sensor sensitivity correction can be achieved.

  Thus, according to the present invention, it is not necessary to recalibrate the sensitivity for each wavelength of each sensor even when the photometric device exhibits different characteristics due to the difference from the reference measuring instrument owned by the user, It is possible to calibrate in a short time to reduce the difference from the reference measuring instrument, and to measure the chromaticity, illuminance, color rendering, etc. of the light under test with high accuracy.

  Further, the present invention does not require a wavelength variable monochromatic light source for calibration, and is very convenient and highly useful.

Example 3
In the second embodiment, the photometric device having a correction function for reducing an error factor caused by such a difference when the reference spectrum of the reference measuring instrument owned by the user is different from the true value spectrum has been described.

  Furthermore, there may be a difference (deviation) between the wavelength accuracy of the reference measuring instrument used by the user and the wavelength accuracy at the time of device calibration at the photometric device manufacturer.

  In the present embodiment, a photometric device having a correction function for reducing an error factor caused by the difference (shift) in wavelength accuracy of the reference measuring device will be described.

  FIG. 8 is a diagram for explaining the influence on the spectral sensitivity characteristics of one of a plurality of sensors of the photometric device when there is a deviation in the wavelength accuracy of the reference measuring instrument. In FIG. 8, the spectral sensitivity characteristic S (λ) indicates the spectral sensitivity characteristic at the time of calibration of the device by the manufacturer of the photometric device. At this time, it is assumed that there is a difference of one square (Δλ), that is, a wavelength deviation between the wavelength accuracy at the time of device calibration at the manufacturer of the photometric device and the wavelength accuracy of the reference measuring device used by the user.

  In the case where there is such a deviation in wavelength accuracy, the photometric device actually measures the value of the wavelength (λk + Δλ) even if the user reference measuring device is set to the wavelength λk, for example. It will be. In other words, the photometric device measures based on the spectral sensitivity characteristic S ′ (λ) taking wavelength deviation into account.

  Therefore, if the wavelength accuracy at the time of calibration of the device by the manufacturer of the photometric device is maintained, an error occurs between the measured value by the reference measuring instrument used by the user and accurate measurement cannot be performed.

  Therefore, in order to reduce the measurement error of the photometric device and obtain the same measurement result as that of the user reference measuring device, the spectral sensitivity characteristic S ′ (λ) in which the spectral sensitivity characteristic is shifted by 1 square (Δλ) is taken into consideration. It is necessary to calculate a weighting coefficient.

  The photometric device of the present embodiment has a control means having a correction function for correcting the wavelength accuracy error.

  A light source for correcting the photometric device 1 is selected. This light source is usually a reference light source (for example, a reference white LED) used for the configuration of a reference measuring instrument used by a user.

  First, the wavelength shift of the reference measuring instrument used by the user is confirmed by a bright line such as a mercury lamp or a gas laser wavelength.

  In order to simplify the explanation, it is assumed that the wavelength shift of the reference measuring instrument used by the user is shifted in one direction by Δλ at each wavelength in the desired wavelength region.

  Therefore, the output (power) measured by the reference measuring instrument used by the user measures the value of the wavelength (λ + Δλ) shifted by Δλ with respect to each set wavelength λ. . Therefore, it is necessary to interpolate the value at the wavelength λ set from the power at the wavelength (λ + Δλ) measured by the reference measuring instrument used by the user.

  In this embodiment, the spectral sensitivity characteristic data S (λ) of each optical sensor SE at the time of calibration of the photometric device can be obtained at intervals of 5 nm in the wavelength region of 380 to 780 nm, for example, the photometric device 1. Are stored in the ROM 105.

Therefore, using the reference light source having the spectral data (spectrum) P (λ), the current spectral sensitivity characteristics S1 (λ), S2 (λ), S3 (λ),. The output from each optical sensor SE in the photometric device it has can be obtained by actually measuring. That means
SE1 output (measurement) = P (λ1) × S1 (λ1) + P (λ2) × S1 (λ2) + ... + P (λk-1) × S1 (λk-1) + P (λk) × S1 (λk) + P (λk + 1) × S1 (λk + 1) + ... + P (λn) × S1 (λn)
SE2 output (measurement) = P (λ1) × S2 (λ1) + P (λ2) × S2 (λ2) + ... + P (λk-1) × S2 (λk-1) + P (λk) × S2 (λk) + P (λk + 1) × S2 (λk + 1) + ... + P (λn) × S2 (λn)
...
SEn output (measurement) = P (λ1) × Sn (λ1) + P (λ2) × Sn (λ2) + ... + P (λk-1) × Sn (λk-1) + P (λk) × Sn (λk) + P (λk + 1) × Sn (λk + 1) + ... + P (λn) × Sn (λn)
It is.

Next, spectral sensitivity characteristics S1 (λ), S2 (λ), S3 (λ),... Sn (λ) at the time of calibration of the photometric device 1 stored in the ROM 105 of the photometric device 1 are used. , From each light receiving element (photoelectric conversion element) PD (PD1, PD2, PD3,..., PDn-2, PDn-1, PDn), that is, each photosensor SE (SE1, SE2, SE3,...). The output (prediction) from SEn-2, SEn-1, SEn) is calculated and obtained. That means
Output of SE1 (prediction) = P '(λ1) × S1 (λ1) + P' (λ2) × S1 (λ2) + ... + P '(λk-1) × S1 (λk-1) + P '(λk) × S1 (λk) + P' (λk + 1) × S1 (λk + 1) + ... + P '(λn) × S1 (λn)
SE2 output (prediction) = P '(λ1) x S2 (λ1) + P' (λ2) x S2 (λ2) + ... + P '(λk-1) x S2 (λk-1) + P '(λk) × S2 (λk) + P' (λk + 1) × S2 (λk + 1) + ... + P '(λn) × S2 (λn)
...
SEn output (prediction) = P '(λ1) × Sn (λ1) + P' (λ2) × Sn (λ2) + ... + P '(λk-1) × Sn (λk-1) + P '(λk) × Sn (λk) + P' (λk + 1) × Sn (λk + 1) + ... + P '(λn) × Sn (λn)
It is.

  Where P ′ (λ1), P ′ (λ2),... P ′ (λk−1), P ′ (λk), P ′ (λk + 1),. It is not a value obtained by measurement directly by the reference measuring instrument used by the user. That is, from the reference measuring instrument used by the user, the spectral data (spectrum PA (λ)) in a state where the wavelength of the reference light source is shifted by Δλ, that is, PA (λ1 + Δλ), PA (λ2 + Δλ) ,... PA (λk-1 + Δλ), PA (λk + Δλ), PA (λk + 1 + Δλ),... PA (λn + Δλ) are only available.

  Therefore, P ′ (λ1), P ′ (λ2),... P ′ (λk−1), P ′ (λk), P ′ (λk + 1),. PA (λ1 + △ λ), PA (λ2 + Δλ), ... PA (λk-1 + △ λ), PA (λk + △ λ), PA (λk + 1 + Δλ), ... PA ( It is necessary to calculate by interpolation based on λn + Δλ).

A method for obtaining P ′ (λk) at wavelength λk by the simplest linear interpolation will be described with reference to FIG.
P ′ (λk) = PA (λk−1 + Δλ) + ΔP ′
here,
ΔP ′ = λA × (ΔPA / λB)
△ PA = PA (λk + 1 + △ λ) −PA (λk-1 + △ λ)
λA = λk− (λk-1 + Δλ)
λB = (λk + 1 + Δλ) − (λk−1 + Δλ) = λk + 1−λk−1
It is.

Here, the ratio between the output (predicted) value and the output (measured) value of each optical sensor SE obtained as described above, that is, the fluctuation ratio, is taken, and correction values (correction coefficients) D1, D2,. ... Dn. That is,
D1 = SE1 output (prediction) / SE1 output (measurement)
D2 = SE2 output (prediction) / SE2 output (measurement)
・ ・ ・ ・ ・ ・
Dn = SEn output (prediction) / SEn output (measurement)
It is.

  The above ratios D1, D2,... Dn are correction values (correction coefficients) determined by the variation ratio of the spectral sensitivity characteristics of the measuring device due to the wavelength shift of the reference light source in the reference measuring instrument used by the user. ) In the ROM 105 of the photometric device 1. And it can be used at the time of calibration of the photometry device 1, and the error factor by the wavelength shift of a reference light source can be reduced.

  That is, for example, if the photometric device of the present invention is used, the tristimulus values are based on the output values of the approximate color matching functions x ′ (λ), y ′ (λ), z ′ (λ) obtained by this device. X, Y, and Z can be calculated and the characteristics of the measurement light can be measured.

At the time of device calibration at this time, as described above, the approximate color matching functions x ′ (λ), y ′ (λ), and z ′ (λ) are expressed by the following equations.
x ′ (λ) = a1 × S1 (λ) + a2 × S2 (λ) +... + an × Sn (λ)
y ′ (λ) = b1 × S1 (λ) + b2 × S2 (λ) +... + bn × Sn (λ)
z ′ (λ) = c1 × S1 (λ) + c2 × S2 (λ) +... + cn × Sn (λ)
Here, a1 to an, b1 to bn, and c1 to cn are weighting coefficients stored in the ROM 105.

Therefore, in this embodiment, the weighting coefficients are further multiplied by correction coefficients D1 to Dn stored in the ROM 105 for correcting the wavelength shift of the reference measuring device. That means
x ′ (λ) = D1 × a1 × S1 (λ) + D2 × a2 × S2 (λ) +... + Dn × an × Sn (λ)
y ′ (λ) = D1 × b1 × S1 (λ) + D2 × b2 × S2 (λ) +... + Dn × bn × Sn (λ)
z ′ (λ) = D1 × c1 × S1 (λ) + D2 × c2 × S2 (λ) +... + Dn × cn × Sn (λ)
It is said.

  According to the present embodiment, as described above, the correction coefficients D1 to Dn for correcting the wavelength deviation of the reference measuring instrument are stored in the ROM 105 of the apparatus, and the correction coefficients are weighted coefficients a1 to an and b1 to bn. , C1 to cn can be multiplied to correct the wavelength shift of the reference measuring instrument.

  As described above, according to the present invention, even if the wavelength shift of the reference measuring device occurs, it is not necessary to recalibrate the sensitivity for each wavelength of each sensor, and the calibration can be performed in a short time. In addition, it is possible to measure the chromaticity, illuminance, etc. of the light under test with high accuracy.

  In the above embodiment, for simplicity of explanation, it is assumed that the wavelength shift of the reference measuring device used by the user is shifted in one direction by Δλ at each wavelength in the desired wavelength region. did.

  However, as shown in FIG. 10, the deviation may be different for each wavelength. In this case, it is necessary to perform interpolation in consideration of the shift of each wavelength. For example, when 400 nm is shifted by +0.5 nm, a value of 400.5 nm is obtained between 400 nm and 405 nm. On the contrary, when it is shifted by -0.5 nm, it is determined from 395 nm and 400 nm.

  Furthermore, the wavelength shift correction of the reference measuring instrument can be performed using calibration wavelengths such as 435.84 nm, 546.07 nm, and 632.82 nm, which are emission line spectra of mercury lamps or the like.

DESCRIPTION OF SYMBOLS 1 Photometry apparatus 10 Detection part 11 Optical sensor means 12 Casing (housing | casing)
13 entrance aperture 14 diffusing plate 100 measuring section 102 A / D converter 103 control means 104 RAM (first storage means)
105 ROM (second storage means)
106 Display means f Optical filter PD Light receiving element SE Optical sensor

Claims (6)

Measurement having a sensitivity characteristic in a wavelength range of a predetermined range and having a light sensor means for receiving light to be tested from the light source to be measured, and measuring the characteristics of the light source to be measured by a light reception signal from the detection unit A photometric device comprising a
The optical sensor means includes an optical filter and a light receiving element, and is configured by arranging a plurality of optical sensors each having a different spectral sensitivity characteristic in which a sensitivity wavelength region is limited,
The measuring unit performs weighting using a predetermined weighting coefficient corresponding to the spectral sensitivity characteristics of the different optical sensors, and multiplies the weighting coefficient by a predetermined correction coefficient to obtain sensitivity of the optical sensor means. A photometric device comprising control means for changing the characteristic to a predetermined characteristic in the wavelength range of the predetermined range.   The detector has a housing in which the optical sensor means is installed, and the housing is provided with an entrance opening through which the light to be tested is incident, and the entrance opening has a diffuser plate. The photometric device according to claim 1, wherein the photometric device is installed. The control means of the measuring unit is
An I / V conversion amplifier that converts a current signal, which is a light reception signal from the optical sensor means, into a voltage; an A / D converter that converts a light reception signal from the I / V conversion amplifier into a digital value; The first storage means for storing the received light signal converted by the D converter and the second storage means for storing the weighting coefficient and the correction coefficient are provided, or The photometric device according to 2. By using the light reception signal stored in the first storage unit and the weighting coefficient stored in the second storage unit, weighting the sensitivity characteristics of each photosensor, and adding them, The spectral sensitivity characteristics of the photosensor after the summation are set to predetermined characteristics for a predetermined wavelength range,
When the spectral sensitivity characteristic of each photosensor changes, the weighting coefficient of each photosensor is multiplied by the correction coefficient determined by the rate of change of the spectral sensitivity characteristic of each photosensor and added. 4. The photometric device according to claim 3, wherein the spectral sensitivity characteristic of the combined optical sensor is set to a predetermined characteristic with respect to a predetermined wavelength range. By using the light reception signal stored in the first storage unit and the weighting coefficient stored in the second storage unit, weighting the sensitivity characteristics of each photosensor, and adding them, The spectral sensitivity characteristics of the photosensor after the summation are set to predetermined characteristics for a predetermined wavelength range,
In order to reduce the difference from the reference measuring instrument possessed by the user, the ratio of the spectral sensitivity characteristics of the photometric device to the reference spectrum of the reference measuring instrument and the true value spectrum of the reference light source used for the reference measuring instrument By multiplying the weighting coefficient of each photosensor by the correction coefficient determined in this way and adding it, the spectral sensitivity characteristic of the combined photosensor is made to be a predetermined characteristic with respect to a predetermined wavelength range. The photometric device according to claim 3, wherein By using the light reception signal stored in the first storage unit and the weighting coefficient stored in the second storage unit, weighting the sensitivity characteristics of each photosensor, and adding them, The spectral sensitivity characteristics of the photosensor after the summation are set to predetermined characteristics for a predetermined wavelength range,
In order to reduce the difference from the reference measuring instrument that the user has, the correction coefficient determined by the variation ratio of the spectral sensitivity characteristic of the photometric device due to the difference in wavelength accuracy of the reference measuring instrument 4. The photometric device according to claim 3, wherein the spectral sensitivity characteristic of the combined photosensor is made a predetermined characteristic with respect to a wavelength range within a predetermined range by multiplying and adding the weighting coefficient of the sensor.

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