JP7432636B2 - How to calibrate a light measurement device - Google Patents

Description

The present invention relates to a method for calibrating a light measuring device.

Patent Document 1 discloses an optical measurement device that measures the optical output of a light source (that is, the optical power measurement device described in Patent Document 1). Furthermore, Patent Document 1 describes a method for correcting the sensitivity of an optical measuring device in order to suppress changes in the measurement accuracy of optical output due to changes in the sensitivity of the optical measuring device depending on the wavelength of the light to be measured. Disclosed. In the method described in Patent Document 1, a plurality of reference light sources each emitting light of a different wavelength is prepared, and the sensitivity of the optical measuring device is corrected using the light emitted from the reference light sources.

Japanese Patent Application Publication No. 2005-195455

Here, the light emitted from the LED (Light Emitting Diode) includes light of a plurality of continuous wavelengths within a certain wavelength range. Therefore, in order to accurately measure the light output of an LED with a light measurement device, the sensitivity of the light measurement device must be corrected by taking into account light of multiple consecutive wavelengths within a certain wavelength range included in the light emitted from the LED. It should be. However, such a viewpoint is not considered at all in Patent Document 1.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a method for calibrating a light measuring device that can suppress wavelength dependence in the measurement accuracy of the light output of an LED.

In order to achieve the above object, the present invention provides a process of determining a group of light emitting conditions for a plurality of light emitting wavelengths, including a plurality of light emitting conditions under which the light emitting wavelengths of the LEDs are equivalent to each other, and comprising: includes a selection of the LED and an input current value to the selected LED, and the LEDs selected under different light emission condition groups are different LEDs having different emission wavelengths; A first acquisition step of obtaining a first measurement result of measuring the light output of the LED emitted according to each light emission condition determined in the step using a prototype; and a first acquisition step of obtaining a first measurement result of measuring the light output of the LED emitted according to each light emission condition determined in the step, and emitting light according to each light emission condition determined in the determination step. a second acquisition step of acquiring a second measurement result obtained by measuring the light output of the LED using a light measurement device to be calibrated; A method for calibrating a light measuring device is provided, comprising: a sensitivity correction step for correcting the sensitivity of the device.

According to the present invention, it is possible to provide a method for calibrating an optical measuring device that can suppress wavelength dependence in the measurement accuracy of the optical output of an LED.

FIG. 1 is a schematic diagram showing the configuration of an optical measurement device to be calibrated in an embodiment. FIG. 2 is a schematic diagram showing the configuration of a prototype in an embodiment. It is a flowchart of the process performed by the calibration method of the optical measuring device in embodiment. It is a graph which shows the relationship between the 1st measurement result P1 and the 2nd measurement result P2 of the light emission condition group 1 in embodiment. A graph showing the relationship between the slope P1(λ)/P2(λ) and the average emission wavelength in the embodiment. It is a graph showing the relationship between the slope Pc1 (λ)/Pc2 (λ) and the average emission wavelength in the embodiment. It is a graph showing the relationship between Pc1 (λ) and Pc2 (λ) in the embodiment.

[Embodiment]
Embodiments of the present invention will be described with reference to FIGS. 1 to 7. The embodiments described below are shown as preferred specific examples for carrying out the present invention, and some portions specifically illustrate various technical matters that are technically preferable. However, the technical scope of the present invention is not limited to this specific embodiment.

FIG. 1 is a schematic diagram showing the configuration of an optical measurement device 1 to be calibrated in this embodiment. FIG. 2 is a schematic diagram showing the configuration of the prototype 10 in this embodiment. The method for calibrating the light measurement device 1 of this embodiment is a method of calibrating the light measurement device 1 with reference to the measurement results of the light output of the LED 100 by the light measurement device 1 and the prototype 10. First, the optical measuring device 1 and the prototype 10 will be explained.

The optical measurement device 1 is an optical measurement device that has not been calibrated so that the measurement results displayed when measuring light of each wavelength in the measurable wavelength range are true values. The measurable wavelength range is a wavelength range in which optical output can be accurately measured in the optical measuring device 1 after calibration. The measurable wavelength range can be, for example, a wavelength range of 250 nm or more and 320 nm or less, and particularly in this embodiment, a wavelength range of 265 nm or more and 300 nm or less. In addition, in this specification, when referring to the emission wavelength with respect to the light emitted from the LED 100, unless otherwise specified, it means the peak wavelength (center wavelength) of the light emitted from the LED 100.

The optical measuring device 1 includes an integrating sphere 2, a light receiving element 3, and a processing section 4. The integrating sphere 2 is formed to be hollow inside and has a spherical inner surface. The inner surface of the integrating sphere 2 is made of a material that can diffusely reflect light. The integrating sphere 2 is formed with an inlet 21 for introducing light from an object to be measured and an outlet 22 for extracting the light to the outside. When light enters the integrating sphere 2 from the inlet 21, the light is repeatedly diffused and reflected on the inner surface of the integrating sphere 2, thereby making the distribution of light intensity inside the integrating sphere 2 uniform. The light extracted from the extraction port 22 is sent to the light receiving element 3. Light propagation is performed using, for example, an optical fiber (not shown). Alternatively, the light receiving element 3 may be directly attached to the opening 22.

When the light receiving element 3 receives light, it outputs a current value according to the light output. In this embodiment, the light receiving element 3 is a silicon photodiode. Since the light receiving element 3 has different sensitivity depending on the wavelength of light it receives, for example, even if the light receiving element 3 receives light with the same optical output, the output current value will be different if the wavelength is different. Taking this into consideration, the processing unit 4 performs processing to increase the measurement precision of the optical output by the optical measuring device 1.

The processing unit 4 calculates the light output of the light received by the light receiving element 3 based on the output current of the light receiving element 3. The processing section 4 includes an I/V conversion section 41, a calculation section 42, a storage section 43, and a display section 44.

The I/V converter 41 converts the current output from the light receiving element 3 into a voltage signal. For example, the I/V converter 41 can be configured with a circuit including an operational amplifier and a resistor. The voltage signal output from the I/V conversion section 41 is sent to the calculation section 42.

The calculation unit 42 performs a process of converting the voltage information acquired from the I/V conversion unit 41 into optical output information according to a predetermined rule. For example, the calculation unit 42 converts the voltage information acquired from the I/V conversion unit 41 into optical output according to a predetermined rule. For example, the calculation unit 42 calculates the optical output of the light to be measured by multiplying the voltage information acquired from the I/V conversion unit 41 by a predetermined coefficient. However, in a state where the optical measurement device 1 is not calibrated, the calculation unit 42 may not be able to accurately calculate the light output of the light of the LED 100 at each wavelength in the measurable wavelength range. Therefore, the optical measurement device 1 is calibrated using the calibration method of this embodiment. In this embodiment, the value of the output current of the light receiving element 3 is converted into voltage information by the I/V converter 41, and this is finally converted into watts or milliwatts. The voltage information acquired from the converter 41 may be displayed as a light output in units of volts [V] or millivolts [mV], or, for example, the I/V converter 41 may be omitted and the voltage information is output from the light receiving element 3. Current information may be displayed as light output in units of amperes [A] or milliamps [mA].

The calculation unit 42 includes a CPU (ie, a calculation processing unit). Furthermore, the storage unit 43 includes a RAM that serves as a calculation area when the CPU operates, and a ROM that stores programs executed by the CPU. The result of the optical output of the light to be measured calculated by the calculation section 42 is sent to the display section 44 .

The display unit 44 displays, for example, the result of the optical output of the measured light received from the calculation unit 42. The display section 44 can be configured with, for example, a liquid crystal display or an organic EL (ie, Electro-Luminescence) display.

The LED 100 whose light output is to be measured by the optical measurement device 1 is a light source that emits light with a wide range of wavelengths (for example, light with a half-value width of 10 nm or more). The LED 100 may be a packaged light-emitting element in which a plurality of semiconductor layers having an AlGaN-based composition are stacked, for example, or may be in a state before the light-emitting element is packaged.

Next, the configuration of the prototype 10 will be explained using FIG. 2.
The prototype 10 is an optical measurement device that is calibrated so that the displayed measurement results are true values when at least light of each wavelength in the measurable wavelength range of the optical measurement device 1 is measured. Various methods can be used to calibrate the prototype 10. The prototype 10 is the same as the optical measurement device 1 except that it includes a spectrometer 102 and is calibrated so that accurate optical output can be calculated at least in the measurable wavelength range of the optical measurement device 1. It has the following configuration. In FIG. 2, the integrating sphere is denoted by 101, the inlet of the integrating sphere is denoted by 101a, the outlet of the integrating sphere is denoted by 101b, the spectrometer is denoted by 102, the light receiving element is denoted by 103, the processing section is denoted by 104, and the I/V The converter is represented by 104a, the calculation part by 104b, the storage part by 104c, and the display part by 104d.

In the prototype 10, light extracted from the outlet 101b of the integrating sphere 101 is sent to the spectrometer 102 through an optical fiber. Then, the spectroscope 102 monochromates the incident light and outputs it. That is, the spectrometer 102 is configured to be able to extract only light of a specific wavelength from among the incident light. The light made monochromatic by the spectroscope 102 is sent to the light receiving element 103. The rest of the configuration of the prototype 10 is the same as that of the optical measuring device 1. Note that when the prototype 10 is a multi-channel detector, the spectrometer 102 is one that operates as a polychromator.

Next, a method for calibrating the optical measuring device 1 will be explained in detail. FIG. 3 is a flowchart of the process performed by the method for calibrating the optical measurement device 1 of this embodiment. In the method for calibrating the optical measurement device 1, a determination step S1, a first acquisition step S2, a second acquisition step S3, a sensitivity correction step S4, a confirmation step S5, and an adjustment step S6 are performed.

The determining step S1 is a step of determining a plurality of light emitting conditions under which a desired light emitting wavelength and light output can be obtained. The light emission condition is a condition for causing the LED to emit light, and includes a selected LED and an input current value. The selected LED is an LED selected from various LEDs so as to have a desired wavelength and optical output. Even if the LEDs are of the same type, the light output and wavelength may vary depending on individual differences, so the LEDs are selected with this in mind. The input current value is a current value input to the selection LED to cause the selection LED to emit light. Note that the LED tends to have a higher light emission output as the input current value becomes higher.

In the determination step S1, a group of light emitting conditions including a plurality of light emitting conditions under which the light emitting wavelengths of the LEDs are equivalent to each other is determined for a plurality of (six in this embodiment) light emitting wavelengths. This will be explained with reference to Table 1 below.

As shown in Table 1, in this embodiment, six light emission condition groups 1 to 6 having different emission wavelengths were determined. The symbol λ listed in Table 1 is the target emission wavelength in each emission condition group. For example, the emission condition group 1 has four emission conditions 1.1 to 1.4 in which the emission wavelength is 265 nm or around 265 nm. In this embodiment, the emission wavelengths in the six emission condition groups 1 to 6 are set to have a pitch of 5 nm or a pitch of 10 nm. For example, the pitch between the emission wavelength of 265 nm in the emission condition group 1 and the emission wavelength of 270 nm in the emission condition group 2 is 5 nm, and the pitch between the emission wavelength of 270 nm in the emission condition group 2 and the emission wavelength of 280 nm in the emission condition group 3 is 10 nm. It has become a pitch.

In this embodiment, the selected LEDs for the plurality of light emitting conditions in one light emitting condition group are five LEDs (for example, LEDs 1.1 to 1.5 in light emitting condition group 1) having the same light output characteristics. The plurality of LEDs having the same light output characteristics are the plurality of LEDs that have the same light output when the input current value is the same. Note that although the number of selection LEDs for a plurality of light emission conditions in one light emission condition group is five in this embodiment, it may be any other number, for example one.

The input current values for each light emitting condition group were 100 mA, 200 mA, 300 mA, and 350 mA. As a result, a plurality of light emitting conditions in each light emitting condition group can be set to the light output level when the input current value is 100 mA, the light output level when the input current value is 200 mA, the light output level when the input current value is 300 mA, and the input current. The conditions were such that four levels of light output could be emitted, including the light output level when the value was 350 mA. In this embodiment, each light emitting condition group has five LEDs with the same light output characteristics as selected LEDs, so each light emitting condition group has five light emitting conditions that provide each level of light output. That will happen. For example, the light emitting condition group 1 has five light emitting conditions 1.1 in which 100 mA is input to each of LEDs 1.1 to 1.5 with the same light output characteristics, but none of these five light emitting conditions 1.1 are also conditions for achieving the same level of light output. The four light output levels may be different or the same in the six light emission condition groups 1 to 6. For example, the light output levels of light emission condition 1.1, light emission condition 2.1, light emission condition 3.1, light emission condition 4.1, light emission condition 5.1, and light emission condition 6.1 may be different from each other. , may be the same as each other. After the determination step S1, a first acquisition step S2 and a second acquisition step S3 are performed.

The first acquisition step S2 is a step of acquiring a first measurement result P1 (λ) that is the result of measuring the light output of the LED emitted according to each light emission condition shown in Table 1 using the prototype 10. The symbol (λ) means that the symbol immediately before it (for example, P1 in the case of P1(λ)) is a function that depends on the wavelength λ. The first measurement result P1 (λ) is obtained by dividing the emitted light of the LED into wavelengths by the spectrometer 102 of the prototype 10, measuring the optical output of each wavelength by the prototype 10, It is obtained by integrating the optical output of each wavelength. The second acquisition step S3 is a step of acquiring a second measurement result P2 (λ) which is the result of measuring the light output of the LED emitted according to each light emission condition shown in Table 1 using the optical measuring device 1. . In the first acquisition step S2 and the second acquisition step S3, the first measurement result P1 (λ) and the second measurement result P2 (λ) may be obtained by measurement by a person who implements the calibration method of this embodiment, The first measurement result P1 (λ) and the second measurement result P2 (λ) obtained by being measured by a third party may be obtained.

Here, as an example, the relationship between the first measurement result P1 and the second measurement result P2 of the light emission condition group 1 is shown in FIG. Each plot in FIG. 4 shows a first measurement result P1 obtained by measuring the optical output of the emitted light when the LED is emitted under the same emission conditions using the prototype 10, and a second measurement result P2 obtained by measuring the optical output using the optical measuring device 1. represents the relationship between In Figure 4, the optical output level when the input current value is 100 mA, the optical output level when the input current value is 200 mA, the optical output level when the input current value is 300 mA, and the optical output level when the input current value is 350 mA. It can be seen that four levels of light output are displayed, including the light output level at The first measurement result P1 (λ) acquired in the first acquisition step S2 and the second measurement result P2 (λ) acquired in the second acquisition step S3 are stored in the storage unit 43. Then, after the first acquisition step S2 and the second acquisition step S3, a sensitivity correction step S4 is performed.

The sensitivity correction step S4 is a step of correcting the sensitivity of the optical measuring device 1 based on the first measurement result P1 (λ) and the second measurement result P2 (λ). The sensitivity correction step S4 is executed by the calculation unit 42. In the sensitivity correction step S4, a slope P1(λ)/P2(λ) obtained by dividing the first measurement result P1(λ) by the second measurement result P2(λ) is calculated. For example, regarding the emission condition group 1 where the emission wavelength is 265 nm, the slope obtained by dividing the first measurement result P1 by the second measurement result P2 can be determined from the slope of the approximate straight line in the graph of FIG. By similarly calculating the slope P1(λ)/P2(λ) for light emission condition groups other than light emission condition group 1, results like the graph in FIG. 5 can be obtained. Note that the horizontal axis in FIG. 5 is the average value of each emission wavelength when the LED is caused to emit light under a plurality of emission conditions constituting each emission condition group.

In FIG. 5, the slope of a portion where there is no plot can be interpolated using an interpolation method such as polynomial interpolation based on the plot portion, for example. Then, in the sensitivity correction step S4, the sensitivity correction of the light measurement device 1 is performed by multiplying the measurement result of the light output of the LED by the light measurement device 1 by the slope shown in FIG. 5 at the wavelength of the light emitted from the LED. It will be done. The relationship between the emission wavelength and the slope as shown in FIG. 5 is stored in the storage unit 43.

Note that the curve shown in FIG. 5 corresponds to a curve proportional to the reciprocal of the sensitivity in the optical measuring device 1 before sensitivity correction. This will be explained. First, let the light output from a certain light source be P(λ)[W], and let the current value output from the light receiving element 3 when the light receiving element 3 is irradiated with light from the light source be I(λ)[A]. , when the sensitivity of the optical measuring device 1 is S(λ), these satisfy the relationship of P(λ)=I(λ)/S(λ)...Equation (1). The current value I(λ) in equation (1) corresponds to k×P2(λ) when applied to the present embodiment. That is, the second measurement result P2(λ) of the optical output by the optical measuring device 1 is the current value output from the light receiving element 3 multiplied by a predetermined coefficient and converted into the optical output value. The value I(λ) is equal to P2(λ) multiplied by a coefficient k expressed as the reciprocal of the predetermined coefficient. That is, I(λ)=k×P2(λ) holds true. When formula 1 is transformed into a formula suitable for this embodiment using this formula, it becomes P1(λ)/P2(λ)=k/S(λ)...Formula (2). From this equation, the curve in the graph of FIG. 5 can be considered to be a curve proportional to the reciprocal of the sensitivity S(λ). From FIG. 5, it can be seen that the optical measurement device 1 in this embodiment has relatively low sensitivity to light having a wavelength of around 280 nm. After the sensitivity correction step S4, a confirmation step S5 is performed.

In the confirmation step S5, the light output of the confirmation LED is measured using the prototype 10 and the optical measuring device 1 after sensitivity correction, and it is determined whether the measurement results by the optical measuring device 1 conform to the measurement results by the prototype 10. This is the process of checking. The confirmation step S5 includes an additional determination step S51, a first confirmation measurement step S52, a second confirmation measurement step S53, and a comparison step S54.

The additional determination step S51 is a step of determining an additional light emitting condition group including a plurality of light emitting conditions under which the light emitting wavelengths of the confirmation LEDs are equivalent to each other for a plurality of (eight in this embodiment) light emitting wavelengths. The confirmation LED means an LED different from the selection LED of each light emission condition determined in the above-described determination step S1, and may be simply referred to as an LED hereinafter. Each light emission condition determined in the additional determination step S51 includes the selected LED and the input current value, similarly to the determination step S1. The selected LED for each light emitting condition determined in the additional determination step S51 was different from the LED used in the aforementioned determination step S1. Furthermore, the selected LEDs for each light emission condition determined in the additional determination step S51 are all different LEDs. Furthermore, the input current values for each light emission condition determined in the additional determination step S51 are the same current value, specifically 350 mA. That is, in the additional determination step S51, various LEDs having different emission wavelengths and light outputs are selected when the same current value is applied to each other. Table 2 shows the emission wavelength and light output level when the LED is caused to emit light according to each emission condition determined in the additional determination step S51.

As shown in Table 2, each additional light emission condition group consists of three light output levels: light output level 1 where the emission wavelength is approximately 50 mW, light output level 2 where the emission wavelength is approximately 60 mW, and optical output level 3 where the emission wavelength is approximately 70 mW. It consists of three light emitting conditions that emit light at the output level. Note that the "average emission wavelength" listed in Table 2 is the average value of the emission wavelength when the LED is caused to emit light according to a plurality of emission conditions of one additional emission condition group.

The average emission wavelength in the plurality of additional emission condition groups was set to approximately 1 nm pitch. For example, the difference between the average emission wavelength in additional emission condition group 1 and the average emission wavelength in additional emission condition group 2 is 0.8 nm, which is approximately 1 nm. Further, the output range between the three optical outputs in each additional light emission condition group (ie, the "output range between three levels" described in Table 2) was set to be 25 mW or less. For example, for additional light emission condition group 1, the light range between the three levels, which is the difference between the maximum value of 69.4 mW and the minimum value of 54.7 mW, is 14 mW or less. .7mW. Furthermore, the output range of the same optical output level in the plurality of additional light emission condition groups (ie, the "output range within each level" listed in Table 2) was set to be 10 mW or less. For example, for light output level 1, the output range within each level, which is the difference between the maximum value of 58.1 mW and the minimum value of 51.5 mW of the light output levels in the plurality of additional light emission condition groups, is: The power output is 6.6mW, which is less than 10mW. Although not listed in Table 2, each additional light emission condition group has a range of emission wavelengths of 1 nm when emitted at three light output levels 1 to 3. That is, in each additional light emission condition group, the difference between the maximum value and the minimum value of the emission wavelength when the LED is emitted at each of light output levels 1 to 3 is 1 nm or less. After the additional determination step S51, a first confirmation measurement step S52 and a second confirmation measurement step S53 are performed.

The first confirmation measurement step S52 is a step of measuring, using the prototype 10, the light output of the confirmation LED emitted according to each light emission condition determined in the additional determination step S51. In the first confirmation measurement step S52, the emitted light of the LED is separated into wavelengths by the spectrometer 102 of the prototype 10, the optical output of each wavelength is measured by the prototype 10, and each of the measured wavelengths is The light output is integrated. The second confirmation measurement step S53 is a step of measuring the light output of the confirmation LED emitted according to each light emission condition determined in the additional determination step S51 using the light measurement device 1 after sensitivity correction. These measurement results are stored in the storage section 43. After the first confirmation measurement step S52, a comparison step S54 is performed.

The comparison step S54 is a step of comparing the measurement results of the first confirmation measurement step S52 and the measurement results of the second confirmation measurement step S53 to confirm the optical measurement accuracy of the optical measurement device 1 after sensitivity correction. The comparison step S54 is executed by the calculation unit 42. In the comparison step S54, a slope Pc1( λ)/Pc2(λ) is calculated for each emission wavelength. A graph of this is shown in FIG.

The graph in FIG. 6 corresponds to the graph in FIG. In other words, the graph in FIG. 5 shows the relationship between the first measurement result P1 (λ) using the prototype 10 and the second measurement result P2 (λ) using the optical measuring device 1 before sensitivity correction for each wavelength. On the other hand, the graph in FIG. 6 shows the relationship between the measurement results of the first confirmation measurement step S52 using the prototype 10 and the measurement results of the second confirmation measurement step S53 using the optical measuring device 1 after sensitivity correction. are shown for each wavelength. As can be seen from FIG. 6, when the optical measuring device 1 after sensitivity correction is used, each plot becomes flat, and it can be seen that the difference in sensitivity for each wavelength in the optical measuring device 1 is almost eliminated. However, since the value of the slope Pc1(λ)/Pc2(λ) deviates from 1, there is still a difference in the optical output measurement results between the optical measuring device 1 and the prototype 10 after sensitivity correction. I understand that. Corrections necessary for the optical measurement device 1 include spectral sensitivity correction and spectral transmittance correction, but the above-mentioned difference may occur due to the spectral transmittance not being corrected in the optical measurement device 1. . Therefore, after the comparison step S54, the adjustment step S6 is performed. How close the value of the slope Pc1(λ)/Pc2(λ) to 1 is to say that the measurement accuracy of the optical measuring device 1 after sensitivity correction is high depends on the measurement accuracy required of the optical measuring device 1. You can decide. Note that the comparison step S54 can also be omitted.

The adjustment step S6 is a step of bringing the optical output measurement result Pc2 (λ) by the optical measurement device 1 closer to the optical output measurement result Pc1 (λ) by the prototype 10, and is executed by the calculation unit 42. The adjustment step S6 creates a relationship between the measurement results of the first confirmation measurement step S52 and the measurement results of the second confirmation measurement step S53, as shown in FIG. Each plot in FIG. 7 shows the optical output of the emitted light when the LED is emitted under the same light emission conditions, as measured by the measurement result Pc1 (λ) using the prototype 10 and the sensitivity-corrected optical measurement device 1. It shows the relationship with the measured result Pc2(λ). Note that the relationship between the measurement results of the first confirmation measurement step S52 and the measurement results of the second confirmation measurement step S53 as shown in FIG. 7 may be created in the confirmation step S5.

In the adjustment step S6, approximate straight lines for each plot in FIG. 7 are calculated and stored in the storage unit 43. In the example of FIG. 7, the relationship between Pc1 and Pc2 is obtained as Pc1=1.3229×Pc2+0.8136. Based on this formula, by multiplying the measurement result Pc2 by the optical measurement device 1 after sensitivity correction by 1.3229 and adding 0.8136, the output result of the optical measurement device 1 and the output result of the prototype 10 are calculated. The calibration of the optical measuring device 1 is completed.

(Actions and effects of embodiments)
The optical measurement device 1 of this embodiment includes a determination step S1, a first acquisition step S2, a second acquisition step S3, and a sensitivity correction step S4. The determination step S1 is a step of determining, for a plurality of light emission wavelengths, a light emission condition group including a plurality of light emission conditions under which the light emission wavelengths of the LEDs are equivalent to each other. The first acquisition step S2 is a step of acquiring a first measurement result P1 (λ) obtained by measuring the light output of the LED emitted according to each light emission condition determined in the determination step S1 using the prototype 10. The second acquisition step S3 is a step of acquiring a second measurement result P2 (λ) obtained by measuring the light output of the LED emitted according to each light emission condition determined in the determination step S1 using the optical measuring device 1 to be calibrated. It is. The sensitivity correction step S4 is a step of correcting the sensitivity of the optical measuring device 1 based on the first measurement result P1 (λ) and the second measurement result P2 (λ). As described above, the method for calibrating the light measuring device 1 of the present embodiment corrects the sensitivity of the light measuring device 1 using an LED having a wavelength width instead of a monochromatic light source. The calibrated optical measuring device 1 can measure the light emitted from the LED with a wide range of wavelengths with high accuracy. Therefore, by the method of configuring the optical measurement device 1 of this embodiment, it is possible to suppress wavelength dependence in the measurement accuracy of the light output of the LED.

Further, each of the plurality of light emission conditions in each light emission condition group has a plurality of conditions that result in light output of each level. As a result, in the optical measurement device 1, the sensitivity correction accuracy for each wavelength can be improved, and the wavelength dependence of the sensitivity of the optical measurement device 1 can be further reduced.

Further, when the emission wavelength of the LED is λ, the first measurement result is P1 (λ), and the second measurement result is P2 (λ), the sensitivity correction step S4 is calculated by P1 (λ) / P2 (λ). The sensitivity of the optical measurement device 1 is corrected based on the expressed sensitivity correction coefficient. Thereby, correction of the sensitivity of the optical measuring device 1 can be realized with simple processing.

Furthermore, the method for calibrating the optical measuring device 1 of this embodiment further includes a confirmation step S5 and an adjustment step S6. In the confirmation step S5, after the sensitivity correction step S4, the light output of the confirmation LED is measured using the optical measurement device 1 and the prototype 10, and the measurement results by the optical measurement device 1 and the measurement results by the prototype 10 are confirmed. It is a process. In the adjustment step S6, when the output result by the optical measurement device 1 and the output result by the prototype 10 are different in the confirmation step S5, the measurement result of the optical output by the optical measurement device 1 is changed to the measurement result of the optical output by the prototype 10. This is the process of bringing it closer. Therefore, the measurement result of the light output of the LED by the optical measuring device 1 after sensitivity correction can be brought closer to the measurement result of the light output of the LED by the prototype 10.

Further, the plurality of light emission conditions in each light emission condition group include conditions in which the current values input to the LEDs are different from each other. In this way, by changing the input current value to change the light output for one LED, it is possible to reduce the number of LEDs selected in the determination step S1. In the determination step S1, it is necessary to select an LED with desired characteristics, so if there are a large number of LEDs to be selected, the selection process takes a long time, and it takes time to calibrate the light measurement device 1. However, in this embodiment, the calibration time of the optical measuring device 1 can be shortened.

Further, the optical measurement device 1 to be calibrated has a photodiode as a light receiving element, and in the determination step S1, a group of light emission conditions is determined for a plurality of light emission wavelengths in the range of 265 nm or more and 300 nm or less. That is, the optical measuring device 1 after calibration can measure wavelengths in the range of 265 nm or more and 300 nm or less with high precision. The sensitivity curve of a photodiode has a complicated shape in the vicinity of the wavelength range of 265 nm to 300 nm, so it is not easy to correct the sensitivity of the photodiode in the vicinity of the wavelength range of 265 nm to 300 nm, unless special measures are taken. do not have. The calibration method of this embodiment can easily perform sensitivity correction regardless of the shape of the sensitivity curve of the light receiving element 3, and is therefore suitably used for sensitivity correction near the wavelength range of 265 nm to 300 nm of photodiodes.

As described above, according to the present embodiment, it is possible to provide a method for calibrating an optical measuring device that can suppress wavelength dependence in the measurement accuracy of the optical output of an LED.

Note that in this embodiment, the plurality of light emission conditions in each light emission condition group include conditions in which the current values input to the LEDs are different from each other; however, the present invention is not limited to this. For example, the plurality of light emission conditions in each light emission condition group, like the plurality of light emission conditions in each additional light emission condition group, use a plurality of LEDs with mutually different light output characteristics, and the current values input to the LEDs are set to be the same. It may also include conditions. Further, in this embodiment, the plurality of light emission conditions of each additional light emission condition group may include conditions in which the current values input to the LEDs are different from each other. Further, in this embodiment, the measurable wavelength range of the optical measuring device 1 after calibration is set to 265 nm or more and 300 nm or less, but it is also possible to set it to a desired wavelength range different from this. In this case, the wavelength range determined in the determination step S1 may be set to a desired wavelength range.

(Summary of embodiments)
Next, technical ideas understood from the embodiments described above will be described using reference numerals and the like in the embodiments. However, each reference numeral in the following description does not limit the constituent elements in the claims to those specifically shown in the embodiments.

[1] The first embodiment of the present invention includes a determining step (S1) of determining a group of light emitting conditions including a plurality of light emitting conditions under which the light emitting wavelengths of the LEDs (100) are equivalent to each other for a plurality of light emitting wavelengths; A first measurement result (P1 (λ)) is obtained by measuring the light output of the LED (100) that is emitted according to each light emission condition determined in the determination step (S1) using the prototype (10). The light output of the LED (100) that was emitted according to the light emission conditions determined in the first acquisition step (S2) and the determination step (S1) was measured using the light measurement device (1) to be calibrated. a second acquisition step (S3) of acquiring a second measurement result (P2(λ)); and a second acquisition step (S3) of acquiring a second measurement result (P2(λ)); This is a method for calibrating a light measuring device (1), comprising a sensitivity correction step (S4) for correcting the sensitivity of the light measuring device (1).
Thereby, it is possible to suppress wavelength dependence in the measurement accuracy of the light output of the LED.

[2] In a second embodiment of the present invention, in the first embodiment, the plurality of light emitting conditions of each light emitting condition group determined in the determining step (S1) are based on the light output of the LED (100). is three or more levels, and the plurality of light emission conditions of each light emission condition group has a plurality of light emission conditions that result in light output of each level.
This further reduces the wavelength dependence of the sensitivity of the optical measuring device.

[3] In the third embodiment of the present invention, in the first or second embodiment, the emission wavelength of the LED (100) is λ, and the first measurement result (P1(λ)) is P1(λ ), and when the second measurement result (P2(λ)) is P2(λ), the sensitivity correction step (S4) is based on a sensitivity correction coefficient expressed by P1(λ)/P2(λ). to correct the sensitivity of the optical measuring device (1).
Thereby, correction of the sensitivity of the optical measuring device can be realized with simple processing.

[4] In a fourth embodiment of the present invention, in the third embodiment, after the sensitivity correction step (S4), the light output of the confirmation LED is adjusted between the light measuring device (1) and the prototype (10). ) and confirming the measurement results by the optical measurement device (1) and the measurement results by the prototype (10); ) is different from the output result of the prototype (10), an adjustment step for bringing the measurement result of the light output by the optical measurement device (1) closer to the measurement result of the light output by the prototype (10). (S6).
Thereby, the optical measurement accuracy of the calibrated optical measuring device can be further improved.

[5] In a fifth embodiment of the present invention, in any one of the first to fourth embodiments, the plurality of light emission conditions of each light emission condition group is a current value input to the LED (100). It is to include conditions that are different from each other.
Thereby, the calibration time of the optical measurement device can be shortened.

[6] In a sixth embodiment of the present invention, in any one of the first to fourth embodiments, the plurality of light emitting conditions of each light emitting condition group include a plurality of the LEDs having mutually different light output characteristics. (100) and includes a condition in which the current values input to the plurality of LEDs (100) are the same.
Thereby, there is no need to variously change the input current value to the LED depending on the light emission conditions, and it is easy to calibrate the optical measuring device.

[7] In a seventh embodiment of the present invention, in any one of the first to sixth embodiments, the light measuring device (1) includes a photodiode as a light receiving element, and the determining step (S1) In this method, the group of light emission conditions is determined for a plurality of light emission wavelengths within a range of 250 nm or more and 320 nm or less.
In any one of the first to sixth embodiments, sensitivity correction can be easily performed regardless of the shape of the sensitivity curve of the light receiving element. Therefore, any one of the first to sixth embodiments is preferably used to correct the sensitivity of the photodiode in the wavelength range from 250 nm to 320 nm, where the shape of the sensitivity curve in the photodiode is complex. It will be done.

(Additional note)
Although the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. Furthermore, it should be noted that not all combinations of features described in the embodiments are essential for solving the problems of the invention. Moreover, the present invention can be implemented with appropriate modifications within a range that does not depart from the spirit thereof.

1...Light measurement device 10...Prototype 100...LED
S1...Determination process S2...First acquisition process S3...Second acquisition process S4...Sensitivity correction process S5...Confirmation process S6...Adjustment process

Claims (7)

A step of determining, for a plurality of light emission wavelengths, a light emission condition group including a plurality of light emission conditions under which the light emission wavelengths of the LEDs are equal to each other, and each of the light emission conditions includes selection of the LEDs and a process for the selection of the LEDs. a determining step in which the LEDs selected under different light emission condition groups are different LEDs having different emission wavelengths ;
a first acquisition step of acquiring a first measurement result of measuring the light output of the LED emitted according to each light emission condition determined in the determination step using a prototype;
a second acquisition step of acquiring a second measurement result obtained by measuring the light output of the LED emitted according to each light emission condition determined in the determination step using a light measurement device to be calibrated;
a sensitivity correction step of correcting the sensitivity of the optical measurement device based on the first measurement result and the second measurement result;
A method for calibrating a light measuring device comprising: The plurality of light emission conditions of each of the light emission condition groups determined in the determination step are conditions under which the light output of the LED is three levels or more,
The plurality of light emission conditions of each of the light emission condition groups have a plurality of light emission conditions that result in light output of each of the levels,
A method for calibrating a light measuring device according to claim 1. When the emission wavelength of the LED is λ, the first measurement result is P1(λ), and the second measurement result is P2(λ), the sensitivity correction step is performed as follows: P1(λ)/P2(λ) correcting the sensitivity of the optical measurement device based on a sensitivity correction coefficient expressed by
A method for calibrating a light measuring device according to claim 1 or 2. After the sensitivity correction step, a confirmation step of measuring the light output of the confirmation LED with the light measurement device and the prototype, and confirming the measurement results by the light measurement device and the measurement results by the prototype;
When the output result by the optical measurement device and the output result by the prototype are different in the confirmation step, an adjustment step of bringing the measurement result of the optical output by the optical measurement device closer to the measurement result of the optical output by the prototype; The method for calibrating an optical measurement device according to claim 3, further comprising: The plurality of light emission conditions in each of the light emission condition groups include conditions in which current values input to the LEDs are different from each other.
A method for calibrating a light measuring device according to any one of claims 1 to 4. The plurality of light emitting conditions in each of the light emitting condition groups include conditions in which a plurality of the LEDs having mutually different light output characteristics are used and the current values input to the plurality of LEDs are the same.
A method for calibrating a light measuring device according to any one of claims 1 to 4. The light measurement device includes a photodiode as a light receiving element,
In the determining step, the group of light emission conditions is determined for a plurality of light emission wavelengths in a range of 250 nm or more and 320 nm or less.
A method for calibrating a light measuring device according to any one of claims 1 to 6.

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