Method for inspecting optical measurement device

Abstract

To provide a method for inspecting an optical measurement device which can easily detect an abnormality in an optical measurement device.SOLUTION: The method for inspecting an optical measurement device includes: regularly measuring light output of a light-emitting device by using the optical measurement device; determining that the optical measurement device is normal when the measured value of light output of the light-emitting device using the optical measurement device is in a predetermined acceptable range; determining that the optical measurement device is abnormal when the measured value is outside the acceptable range; and updating the acceptable range with time.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a method for inspecting an optical measurement device. [Background technology]

[0002] Patent Document 1 discloses a method for measuring the light output of an LED (Light Emitting Diode) as a light emitting device using a light measuring device having an integrating sphere or an integrating hemisphere. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2012-227201 A Summary of the Invention [Problem to be solved by the invention]

[0004] Although a light measurement device may be calibrated before use to improve the accuracy of measuring the light output, the condition of the light measurement device may change over time, and an abnormality may occur in the light measurement device.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a method for inspecting a light measurement device that makes it easy to detect an abnormality in the light measurement device. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a method for inspecting a light measuring device, which periodically measures the light output of a light emitting device using a light measuring device, and judges the light measuring device to be normal if the measured value of the light output of the light emitting device using the light measuring device is within a predetermined passing range, and judges the light measuring device to be abnormal if the measured value is outside the passing range, and updates the passing range over time. Effect of the Invention

[0007] According to the present invention, it is possible to provide a method for inspecting a light measurement device that makes it easy to detect an abnormality in the light measurement device. [Brief description of the drawings]

[0008] [Figure 1] 1 is a schematic diagram showing a configuration of a light emitting device and a light measuring device according to an embodiment; [Diagram 2] 1 is a graph showing hypothetical measurement data of the light output of a light emitting device together with the pass range of a first comparative example. [Diagram 3] 13 is a graph showing hypothetical measurement data of the light output of a light emitting device together with the pass range of a second comparative example. [Figure 4] 1 is a graph showing hypothetical measurement data of the light output of a light emitting device according to an embodiment, together with a safe range and an acceptable range. [Diagram 5] FIG. 5 is an enlarged view of a portion of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Embodiment Mode] An embodiment of the present invention will be described with reference to Figures 1 to 5. Note that the embodiment described below is shown as a preferred specific example for carrying out the present invention, and while there are some parts that specifically exemplify various technical matters that are technically preferable, the technical scope of the present invention is not limited to this specific embodiment.

[0010] This embodiment is directed to a method for inspecting a light measuring device for detecting an abnormality in the light measuring device that measures the light output of a light emitting device. First, the light emitting device and the light measuring device will be described.

[0011] FIG. 1 is a schematic diagram showing the configurations of a light emitting device 1 and a light measuring device 2. As shown in FIG. The light emitting device 1 is, for example, a light emitting diode (LED). The light emitting device 1 is not particularly limited, but may be a light emitting diode having a so-called CoS (Chip on Submount) structure, a so-called airtight sealed structure, etc. The light emitting device 1 may be a light source other than a light emitting diode.

[0012] In this embodiment, the light emitting device 1 is, for example, an ultraviolet LED that emits ultraviolet light with a central wavelength of 365 nm or less. The light emitting device 1 may also emit deep ultraviolet light with a central wavelength of 280 nm or less.

[0013] The light measurement device 2 is a device capable of measuring the light output of the light emitting device 1. In this embodiment, the light measurement device 2 includes an integrating sphere 21, a light receiving element 22, and a control unit .

[0014] Integrating sphere 21 is formed so as to be hollow inside, and its inner surface is formed in a spherical shape. The inner surface of integrating sphere 21 is made of a material capable of diffusively reflecting light. Integrating sphere 21 is formed with inlet 211 for introducing light emitted from light emitting device 1 into integrating sphere 21, and outlet 212 for extracting the light inside integrating sphere 21 to the outside.

[0015] When light emitted from light emitting device 1 is introduced into integrating sphere 21 from inlet 211, the light is repeatedly diffusely reflected on the inner surface of integrating sphere 21, thereby homogenizing the distribution of light intensity inside integrating sphere 21. Then, the light inside integrating sphere 21 is extracted from outlet 212 formed in integrating sphere 21 and sent to light receiving element 22. The light can be transmitted from integrating sphere 21 to light receiving element 22 using an optical fiber. Note that light receiving element 22 may be directly attached to outlet 212 of integrating sphere 21.

[0016] When the light receiving element 22 receives light, it outputs a current value corresponding to the optical output. In this embodiment, the light receiving element 22 is a photodiode such as a silicon photodiode. The output of the light receiving element 22 is sent to the control unit 23.

[0017] The control unit 23 calculates the optical output of the light received by the light receiving element 22 based on the output current of the light receiving element 22. The control unit 23 includes an I / V conversion unit 231 and a calculation unit 232.

[0018] The I / V conversion unit 231 converts the current output from the light receiving element 22 into a voltage signal. For example, the I / V conversion unit 231 can be configured with a circuit having an operational amplifier and a resistor. The voltage signal output from the I / V conversion unit 231 is sent to the calculation unit 232.

[0019] The calculation unit 232 performs a process of converting the voltage information acquired from the I / V conversion unit 231 into light output information in accordance with a predetermined rule. For example, the calculation unit 232 converts the voltage information acquired from the I / V conversion unit 231 into light output in accordance with a predetermined rule. For example, the calculation unit 232 calculates the light output of the light emitting device 1 by multiplying the voltage information acquired from the I / V conversion unit 231 by a predetermined coefficient.

[0020] The calculation unit 232 converts the voltage information acquired from the I / V conversion unit 231 into optical output information in units of watts [W] or milliwatts [mW]. However, without being limited thereto, the calculation unit 232 may convert the voltage information acquired from the I / V conversion unit 231 into optical output information in units of volts [V] or millivolts [mV], or may eliminate the I / V conversion unit 231 and convert information on the current output from the light receiving element 22 into optical output information in units of amperes [A] or milliamperes [mA]. ​​Furthermore, the calculation unit 232 also sets and updates a safety range and an acceptable range, which will be described later.

[0021] The calculation unit 232 includes a processor, a memory such as a RAM (Random Access Memory) that serves as a calculation area during operation of the processor, and a ROM (Read Only Memory) that stores programs executed by the processor and various data calculated by the processor. The calculation unit 232 may be realized by any method other than software as long as it is configured to realize its functions. For example, at least a part of the functions of the control unit 23 may be realized by hardware such as a logic circuit. The optical output information calculated by the calculation unit 232 is output to, for example, a display (not shown).

[0022] Next, a method for inspecting the light measurement device 2 of this embodiment will be described. First, Fig. 2 shows a hypothetical example of the results of measuring the light output of the light emitting device 1 once a day from January 1, 2023 to January 31, 2024 using a light measuring device 2. In Fig. 2, the horizontal axis represents the date and the vertical axis represents the light output. The light output is a relative light output obtained by dividing the measured value by a predetermined reference value.

[0023] In the hypothetical example of FIG. 2, it is assumed that the daily measurement is performed by emitting light from the light emitting device 1 for only a short time, for example, a few milliseconds, and that the light emitting device 1 is assumed to be one whose true value of the light output does not change if the light is emitted for a short period of time as described above. In the hypothetical example of FIG. 2, it is assumed that an abnormality occurs in the light measuring device 2 on April 1, 2023, July 1, 2023, and November 1, 2023, and the measured value of the light output of the light emitting device 1 increases or decreases sharply compared to the previous day. The abnormality of the light measuring device 2 is assumed to be due to factors such as the intrusion of foreign matter into the light measuring device 2. In addition, in FIG. 2, it is assumed that each time an abnormality is detected, the light measuring device 2 is inspected to eliminate the abnormality, and the light measuring device 2 returns to a normal state from the next day.

[0024] 2, the measurement result of the light output of the light emitting device 1 by the light measuring device 2 fluctuates up and down over time. This is assumed to be due to changes in the reflectance, transmittance, etc. of each part of the light measuring device 2 caused by changes in the environment around the light measuring device 2 due to seasonal changes, for example. In addition, when measuring the light output of the light emitting device 1 that emits ultraviolet light as in this embodiment, it can be assumed that the state of the light measuring device 2 changes due to the influence of the ultraviolet light.

[0025] Here, as shown in Fig. 2, a case will be considered in which the initial measurement result of the light output of the light emitting device 1 (i.e., the measurement result on January 1, 2023) is used as the standard and a relatively narrow range above and below the measurement result is uniformly set as the pass range. The pass range is the range of measurement values ​​of the light output of the light emitting device 1 measured by the light measuring device 2 that is assumed to be obtained when the light measuring device 2 is in a normal state, and in Fig. 2, the upper and lower limits of the pass range are indicated by dashed lines. In the example shown in Fig. 2, due to the upward and downward transitions of the measurement values ​​as described above, there is a risk that the light measuring device 2 may be erroneously determined to be abnormal even when it is normal.

[0026] Therefore, as shown in Figure 3, it is conceivable to set the upper limit of the pass range to a value that is assumed to be higher than the upward and downward trends in the measured values ​​as described above, and to set the lower limit of the pass range to a value that is assumed to be lower than the upward and downward trends in the measured values ​​as described above.

[0027] However, in this case, while it is possible to detect abnormal values ​​that stand out relatively significantly from the upward and downward trends in the measurement values, such as on April 1, 2023, it is not possible to detect abnormal values ​​that do not stand out from the upward and downward trends in the measurement values, or that do stand out only slightly, such as on July 1, 2023 and November 1, 2023.

[0028] Taking the above circumstances into consideration, the inspection method for the light measuring device 2 in this embodiment makes it easier to detect abnormalities in the light measuring device 2 by updating the pass range over time to track the daily measurement results of the light emitting device 1 by the light measuring device 2.

[0029] 4 is a diagram showing the upper and lower limits of a safe range and a pass range, which will be described later, in the inspection method of the light measurement device 2 of this embodiment in the above-mentioned hypothetical example. In FIG. 4, the upper and lower limits of the safe range are shown by thin solid lines, and the upper and lower limits of the pass range are shown by dashed lines.

[0030] In the inspection method of the light measurement device 2 of this embodiment, the light output of the light emitting device 1 is periodically measured using the light measurement device 2. Periodic measurement includes, for example, daily measurement performed at least once a day, as well as measurement performed, for example, on the majority of days (i.e., four or more days) a week. In this embodiment, an example is assumed in which the light output of the light emitting device 1 is measured once a day using the light measurement device 2.

[0031] In the inspection method for the light measurement device 2 of this embodiment, if the measured value of the light output of the light emitting device 1 using the light measurement device 2 is within the pass range, the light measurement device 2 is determined to be normal, and if it is outside the pass range, the light measurement device 2 is determined to be abnormal. As described above, the inspection method for the light measurement device 2 of this embodiment updates the pass range over time.

[0032] In this embodiment, a safety range narrower than the pass range is set, and both the safety range and the pass range are updated when the measurement value of the light output of the light emitting device 1 by the light measuring device 2 falls outside the safe range but within the pass range.

[0033] Each of the safe range and the pass range is a predetermined range above and below the reference value of the measurement value of the light output of the light emitting device 1 using the light measuring device 2 at the time when the safety range and the pass range are set. The reference value is an average value calculated using measurement value data from a predetermined period of the past (e.g., the past 10 to 30 days, etc.) from the time when the safety range and the pass range are set. The reference value may be a representative value other than the average value. Furthermore, each of the safe range and the pass range may be a predetermined range above and below the measurement value at the time when the safety range and the pass range are set.

[0034] Furthermore, the "predetermined range above and below" the reference value for the safety range and the pass range is determined based on a standard deviation σ calculated using data of measurements from a specified period in the past (e.g., the past 10 to 30 days, etc.) from the time the safety range and the pass range are set. In this embodiment, the safety range is set to a range of ±2σ from the reference value, and the pass range is set to a range of ±3σ from the reference value. However, without being limited to this, the "predetermined range above and below" from the reference value for the safety range may be, for example, a range of x% above and below the reference value, and the "predetermined range above and below" from the reference value for the pass range may be, for example, a range of y% above and below the reference value (y>x).

[0035] In the initial measurement of the light output of the light emitting device 1 using the light measuring device 2, the initial settings of the safe range and the acceptable range may be made based on measurement data that is accumulated multiple times before the initial measurement. Also, when there is no measurement data as described above, the initial settings of the safe range and the acceptable range may be made based on the initial measured value of the light output of the light emitting device 1. Just do that.

[0036] In the inspection method for the optical measurement device 2 of this embodiment, the safety range and the pass range are updated in response to measurement values ​​outside the safe range and within the pass range being obtained multiple times within a predetermined period. In this embodiment, when the measurement values ​​are outside the safe range and within the pass range for two consecutive days, the safety range and the pass range are reset. This will be described later with reference to FIG. 5.

[0037] Figure 5 is an expanded version of the data in Figure 4 from January 1, 2023 to February 1, 2023. As shown in Figure 5, the measured value on January 21, 2023 is outside the safe range and within the acceptable range, but the measured value returns to the safe range on the following January 22, 2023. Also, the measured value on January 24, 2023 is outside the safe range and within the acceptable range, but the measured value returns to the safe range on the following January 25, 2023. In these cases, the safe range and the acceptable range are not updated.

[0038] On the other hand, the measurement values ​​were outside the safe range but within the pass range for two consecutive days on January 26, 2023 and January 27, 2023. When the measurement values ​​are outside the safe range but within the pass range for two consecutive days like this, the safety range and pass range will be updated, and operations will continue within the updated safety range and pass range from the following January 28, 2023.

[0039] In this embodiment, the light output of the light emitting device 1 is measured once a day, but in a case where the light output of the light emitting device 1 may be measured multiple times a day, for example, if there are multiple pieces of measurement data that are outside the safe range but within the acceptable range in the measurement data for two days, the current day and the day before, the safety range and the acceptable range may be updated. For example, if there are multiple measurement values ​​that are outside the safe range but within the acceptable range as measurement data for a specific day, the safety range and the acceptable range are updated from the day after the specific day, even if all the measurement data for the day before that day were within the safe range.

[0040] The timing for updating the safe range and the pass range is not limited to the above timing. For example, the pass range may be updated if a measurement value that is outside the safe range and within the pass range is obtained at least once. Also, for example, the pass range may be updated periodically, or may be updated every time the light output of the light emitting device 1 is measured. In these cases, it is not necessary to set the safety range.

[0041] 4, if the measured value falls outside the acceptable range, it is determined that some abnormality has occurred in the light measurement device 2. The light measurement device 2 may include a notification unit that issues an alarm or the like when the measured value of the light output of the light emitting device 1 falls outside the acceptable range.

[0042] If the measured value falls outside the acceptable range, for example, the cause of the abnormality of the light measurement device 2 is investigated. If an abnormality of the light measurement device 2 is found and measures are taken to eliminate the abnormality, the light measurement device 2 can be used continuously. In such a case, the calculation of the above-mentioned guideline value, safe range, and acceptable range is performed while ignoring the data of the abnormal value.

[0043] (Functions and Effects of the Embodiments) In the inspection method for the light measurement device 2 of this embodiment, the pass range is updated over time. Therefore, an abnormality in the light measurement device 2 is easily detected.

[0044] The pass range is a predetermined range above and below the target value of the measurement value at the time the pass range is set. Therefore, the pass range can be set according to the measurement value at the time the pass range is set, and the pass range can be easily made to follow the daily fluctuations of the measurement value. Therefore, abnormalities in the light measurement device 2 are more easily detected.

[0045] The reference value is an average value calculated using the measurement value data from a predetermined period of time from the time the pass range is set. Therefore, the reference value of the measurement value at the time the pass range is set is a value that suppresses the measurement variation of the light output. Therefore, an abnormality in the light measurement device 2 is more easily detected.

[0046] The upper and lower predetermined ranges are determined based on a standard deviation calculated using data on the measured values ​​from a predetermined period in the past from the time the acceptable range was set. By using the standard deviation in this way, the acceptable range is more likely to be the range of the measured values ​​of the light output of the light emitting device 1 measured by the normal light measuring device 2, and as a result, an abnormality in the light measuring device 2 is more easily detected.

[0047] Furthermore, the inspection method for the light measuring device 2 of this embodiment updates the safety range and the pass range when the measured value of the light output of the light emitting device 1 is outside a predetermined safe range that is narrower than the pass range but is within the pass range. This makes it possible to detect that the measurement result of the light output of the light emitting device 1 by the light measuring device 2 is tending to change when the measured value is outside the safe range but within the pass range, and to update the pass range at an appropriate timing.

[0048] Furthermore, the inspection method for the light measuring device 2 of this embodiment updates the safe range and the pass range in response to measurement values ​​outside the safe range and within the pass range being obtained multiple times within a predetermined period of time. In this way, when measurement data outside the safe range and within the pass range is repeatedly obtained within a predetermined period of time, it can be determined that there is a high degree of certainty that the measurement results of the light output of the light emitting device 1 by the light measuring device 2 are showing a tendency to change, and the pass range can be updated at a more appropriate time.

[0049] Furthermore, the light emitting device 1, which is the object of measurement of the light output by the light measuring device 2, emits ultraviolet light. Therefore, the light measuring device 2 is likely to receive ultraviolet light and develop some kind of abnormality, and therefore the inspection method of this embodiment, which can easily detect abnormalities in the light measuring device 2, is preferably used.

[0050] As described above, according to this embodiment, it is possible to provide a method for inspecting a light measurement device that makes it easy to detect an abnormality in the light measurement device.

[0051] (Summary of the embodiment) Next, the technical ideas grasped from the above-described embodiment will be described by using the reference numerals and the like in the embodiment. However, the reference numerals and the like in the following description do not limit the components in the claims to the members and the like specifically shown in the embodiment.

[0052] [1] A first embodiment of the present invention is a method for inspecting a light measuring device 2, which comprises periodically measuring the light output of a light emitting device 1 using a light measuring device 2, judging the light measuring device 2 to be normal if the measured value of the light output of the light emitting device 1 using the light measuring device 2 is within a predetermined pass range, and judging the light measuring device 2 to be abnormal if the measured value is outside the pass range, and updating the pass range over time. This makes it easier to detect an abnormality in the light measurement device 2.

[0053] [2] A second embodiment of the present invention is the first embodiment, wherein the pass range is a predetermined range above and below the target value of the measurement value at the time the pass range is set. This makes it easier to detect an abnormality in the light measurement device 2.

[0054] [3] A third embodiment of the present invention is that, in the second embodiment, the reference value is an average value calculated using the measurement value data for a predetermined period of time from the time the pass range was set. This makes it easier to detect an abnormality in the light measurement device 2.

[0055] [4] A fourth embodiment of the present invention is that, in the second or third embodiment, the upper and lower specified ranges are determined based on a standard deviation calculated using the measurement value data for a specified period of time from the time the pass range is set. This makes it easier to detect an abnormality in the light measurement device 2.

[0056] [5] A fifth embodiment of the present invention is, in any one of the first to fourth embodiments, that when the measurement value is outside a predetermined safety range narrower than the pass range but within the pass range, the safety range and the pass range are updated. This allows the pass range to be updated at an appropriate time.

[0057] [6] A sixth embodiment of the present invention is, in the fifth embodiment, to update the safety range and the pass range in response to the measurement value being outside the safety range and within the pass range being obtained multiple times within a predetermined period. This allows the pass range to be updated at an appropriate time.

[0058] [7] A seventh embodiment of the present invention is any one of the first to sixth embodiments, wherein the light emitting device 1 emits ultraviolet light. As a result, some abnormality is likely to occur when the light measurement device 2 is exposed to ultraviolet light, and therefore the inspection method of the present invention, which makes it easy to detect abnormalities in the light measurement device 2, is preferably used.

[0059] (Additional Note) Although the embodiment of the present invention has been described above, the invention according to the claims is not limited to the above embodiment. It should be noted that not all of the combinations of features described in the embodiment are essential to the means for solving the problems of the invention. The present invention can be modified appropriately without departing from the spirit of the invention. [Explanation of symbols]

[0060] 1...Light emitting device 2. Optical measurement device

Claims

1. Periodically measuring the light output of the light emitting device using a light measurement device; If a measured value of the light output of the light emitting device using the light measuring device is within a predetermined pass range, the light measuring device is judged to be normal, and if a measured value is outside the pass range, the light measuring device is judged to be abnormal; The pass range is updated over time. How to check optical measurement equipment.

2. The pass range is a predetermined range above and below the target value of the measurement value at the time of setting the pass range. The method for inspecting a light measurement device according to claim 1 .

3. The reference value is an average value calculated using the data of the measurement values ​​for a predetermined period of time from the time when the pass range was set. The method for inspecting a light measurement device according to claim 2.

4. The upper and lower predetermined ranges are determined based on a standard deviation calculated using the measurement value data for a predetermined period of time from the time point when the pass range was set.

4. A method for inspecting a light measuring device according to claim 2 or 3.

5. If the measurement value is outside a predetermined safety range that is narrower than the pass range but is within the pass range, the safety range and the pass range are updated.

3. A method for inspecting a light measuring device according to claim 1 or 2.

6. updating the safety range and the pass range in response to the measurement value being outside the safety range and within the pass range being obtained a plurality of times within a predetermined period of time; The method for inspecting a light measurement device according to claim 5.

7. The light emitting device emits ultraviolet light.

3. A method for inspecting a light measuring device according to claim 1 or 2.

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