JPWO2018110267A1 - Reflection / transmission characteristic measuring device - Google Patents

Abstract

It is possible to suppress the occurrence of errors in the reflection / transmission characteristics, suppress the complexity of the structure of the reflection / transmission characteristic measurement apparatus, and suppress the control from being complicated in the reflection / transmission characteristic measurement apparatus. In the reflection / transmission characteristic measuring apparatus, the detection signal corresponding to the reflected light or transmitted light is integrated and an integrated signal is output. (1) White calibration is performed when the integral signal is the first integral signal when white calibration is performed and the integral signal is the second integral signal when measurement is performed. Sometimes, at least one light emission time is corrected, in which illumination light is emitted only for a first light emission time included in at least one light emission time, and the corrected at least one light emission time becomes longer as the first integrated signal becomes smaller. (2) When measurement is performed, illumination light is emitted for a second light emission time included in at least one light emission time.

Description

  The present invention relates to a reflection / transmission characteristic measuring apparatus.

  The spectrocolorimeter is a device that measures the spectral reflection characteristics of a sample.

  The spectrocolorimeter irradiates a sample with illumination light, and measures the spectral characteristics and the like of reflected light generated by the sample reflecting the illumination light.

  In a spectrocolorimeter, for example, a light-emitting circuit supplies power necessary for a light-emitting operation to a light source, the light source performs a light-emitting operation that emits illumination light, and a photodetector outputs a detection signal corresponding to reflected light. The integration circuit integrates the detection signal and outputs an integration signal, and the arithmetic processing unit calculates the result of spectral colorimetry from the output integration signal.

  The characteristics of the elements included in the light source provided in the spectrocolorimeter and the light emitting circuit provided in the spectrocolorimeter depend on the environment and change with time. For this reason, the measurement performance of the spectrocolorimeter also depends on the environment and changes with time. For example, when the environmental temperature changes, the power supplied by the light emitting circuit changes, the amount of illumination light emitted from the light source changes, the amount of reflected light received by the photodetector changes, and the spectrocolorimeter The measurement performance changes. Further, as time passes, the light source deteriorates, the amount of light emitted from the light source decreases, the amount of reflected light received by the photodetector decreases, and the measurement performance of the spectrocolorimeter changes.

  In a reflection characteristic measurement device such as a spectrocolorimeter, calibration may be performed so that measurement can be performed accurately even when the amount of light emitted from the light source changes. The techniques described in Patent Documents 1 and 2 are an example.

  In the technique described in Patent Document 1, the brightness of a light source is measured by a brightness detection sensor, and when it is determined that the brightness of the light source is not normal, the brightness of the light source is adjusted to a normal brightness. (Paragraphs 0027 and 0028). According to the technique described in Patent Document 1, the brightness of the light source is maintained at a normal value, and the measurement reliability is improved (paragraphs 0030 and 0034).

  In the technique described in Patent Document 2, when a white calibration plate is arranged in a position that does not interfere with the measurement in the field of view of the line sensor and is in focus with the line sensor, and the color measurement is performed, the white calibration plate is used. Is taken and the amount of energy attenuation over time of the lamp is calculated, a correction value for correcting the color measurement data by the amount of attenuation is obtained, and the color measurement value is multiplied by the correction value (paragraphs 0008, 0012 and 0035). . According to the technique described in Patent Document 2, stable color measurement values can be obtained (paragraph 0035).

JP-A-7-55704 JP 2001-99708 A

  In the conventional technique represented by the technique described in Patent Document 1, the intensity of the illumination light is changed. Therefore, the spectral intensity of the illumination light changes with the change of the intensity of the illumination light, and is measured. An error may occur in the reflection characteristics. For example, in the technique described in Patent Document 1, since the brightness of the light source is adjusted, the spectral intensity of the projected light changes as the brightness of the light source is adjusted. There may be an error in accuracy.

  In the conventional technique represented by the technique described in Patent Document 1, a mechanism for monitoring the intensity of illumination light is required, and problems such as a complicated structure of the reflection characteristic measuring apparatus arise. For example, in the technique described in Patent Document 1, a brightness detection sensor for measuring the brightness of a light source is required, and problems such as a complicated structure of a painted surface property measuring apparatus arise.

  In the conventional technique represented by the technique described in Patent Document 2, a correction error may occur in the reflection characteristic because the spectral reflection characteristic is corrected. For example, in the technique described in Patent Document 2, since a correction value is multiplied by a color measurement value, a correction error may occur in the color measurement value.

  In the conventional technique represented by the technique described in Patent Document 2, since the spectral reflection characteristics are corrected, problems such as complicated control occur in the reflection / transmission characteristic measurement apparatus.

  These problems also occur in reflection characteristic measurement devices other than the spectrocolorimeter. These problems also occur in the transmission characteristic measuring apparatus.

  The invention described in the detailed description of the invention aims to solve these problems. The problems to be solved by the invention described in the detailed description of the invention are to suppress the occurrence of errors in reflection characteristics / transmission characteristics, to suppress the complexity of the structure of the reflection / transmission characteristics measurement apparatus, and to reflect / To prevent the control from becoming complicated in the transmission characteristic measuring apparatus.

  The reflection / transmission characteristic measurement apparatus includes a light source, a light emitting circuit, a photodetector, an integrator, a storage unit, a control unit, and an arithmetic processing unit.

  The light source emits illumination light applied to the sample.

  The light emitting circuit supplies power required for emitting illumination light to the light source.

  The photodetector outputs a detection signal corresponding to the reflected light or transmitted light. The reflected light is generated when the sample reflects the illumination light. The transmitted light is generated when the sample transmits the illumination light.

  The integrator integrates the detection signal and outputs an integration signal.

  The storage unit stores at least one light emission time.

  If the integrated signal is the first integrated signal when white calibration is performed and the integrated signal is the second integrated signal when measurement is performed, (1) white When calibration is performed, the light source circuit is controlled so that the light source emits illumination light for a first light emission time included in at least one light emission time. As the first integrated signal becomes smaller, at least one after correction is performed. A correction process for increasing the light emission time is performed on at least one light emission time. (2) When measurement is performed, the light source emits illumination light for a second light emission time included in at least one light emission time. The light emitting circuit is controlled.

  The arithmetic processing unit calculates the reflection / transmission characteristics of the sample from the second integration signal.

  According to the invention described in the detailed description of the invention, errors in the reflection / transmission characteristics are suppressed, and the structure of the reflection / transmission characteristic measuring apparatus is suppressed from being complicated, and reflection / transmission characteristic measurement is performed. It is possible to suppress the control from becoming complicated in the apparatus.

  The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

1 is a block diagram illustrating a spectrocolorimeter according to a first embodiment. It is a figure which shows the table memorize | stored in the spectral colorimeter of 1st Embodiment. It is a graph which illustrates the change by the temperature of the light emission circuit of the light emission amount of the light source in the spectrocolorimeter of 1st Embodiment. It is a flowchart which illustrates the procedure of the white calibration performed in the spectrocolorimeter of 1st Embodiment. It is a flowchart which illustrates the procedure of the measurement performed in the spectrocolorimeter of 1st Embodiment.

1 First Embodiment 1.1 Spectral Colorimeter FIG. 1 is a block diagram illustrating a spectral colorimeter according to a first embodiment.

  The spectrocolorimeter 1000 illustrated in FIG. 1 irradiates the sample 1020 with the illumination light 1040, receives the reflected light 1041 generated when the sample 1020 reflects the illumination light 1040, and obtains the spectral intensity of the reflected light 1041. The colorimetric value of the sample 1020 is obtained from the spectral intensity. Reflective characteristics other than the colorimetric values may be obtained instead of or in addition to the colorimetric values. For example, spectral reflectance may be obtained. Instead of the reflected light 1041, transmitted light generated when the sample 1020 transmits the illumination light 1040 may be received. When transmitted light is received instead of the reflected light 1041, the spectrocolorimeter 1000, which is a reflection characteristic measurement device that obtains reflection characteristics, becomes a transmission characteristic measurement device that obtains transmission characteristics. The spectrocolorimeter 1000 that is a spectrocolorimetric reflection characteristic measurement apparatus may be replaced with a colorimeter that is a stimulus value direct reading reflection characteristic measurement apparatus.

  The spectrocolorimeter 1000 includes a light source 1060, a light emission circuit 1061, a photodetector 1062, an integrator 1063, an A / D converter 1064, a control calculation unit 1065, a storage unit 1066, a temperature detector 1067, and a display unit 1068. The photodetector 1062 includes a light receiving element 1080. The integrator 1063 includes an integration circuit 1100. The control calculation unit 1065 includes a control unit 1120 and a calculation unit 1121. The spectrocolorimeter 1000 may include components other than these components.

  The light source 1060 is a xenon flash lamp, a light emitting diode (LED), or the like, and emits illumination light 1040.

  The light emitting circuit 1061 supplies power necessary for emitting the illumination light 1040 to the light source 1060.

  The photodetector 1062 outputs a detection signal 1140 corresponding to the reflected light 1041. The light receiving element 1080 is also called a photosensor, receives the reflected light 1041, and outputs a current corresponding to the reflected light 1041. The detection signal 1140 is a current output from the light receiving element 1080. When transmitted light is received instead of the reflected light 1041, the photodetector 1062 outputs a detection signal corresponding to the transmitted light.

  The integration circuit 1100 integrates the detection signal 1140 and outputs an integration signal 1160. The integration signal 1160 is obtained by converting the current output from the light receiving element 1080 into a voltage.

  The A / D converter 1064 converts the integration signal 1160 that is an analog electrical signal into an integration signal 1180 that is a digital electrical signal.

  The control operation unit 1065 is an embedded computer and operates according to installed firmware. A part of the function of the control arithmetic unit 1065 may be carried by hardware that does not execute software. The control unit 1120 controls the light emitting circuit 1061. The calculation unit 1121 calculates the colorimetric value of the sample 1020 from the integrated signal 1180. Therefore, the A / D converter 1064 and the calculation unit 1121 constitute a calculation processing unit 1190 that calculates the colorimetric value of the sample 1020 from the integrated signal 1160.

  The storage unit 1066 stores information output from the control calculation unit 1065, and stores a table, a measurement count, and a correction count described later. The number of times of measurement is the number of times a measurement described later has been performed. The number of corrections is the number of times correction processing described later has been performed.

  The temperature detector 1067 detects the temperature of the light emitting circuit 1061. The temperature inside the spectrocolorimeter 1000 other than the temperature of the light emitting circuit 1061 may be detected.

  The display unit 1068 displays information output from the control calculation unit 1065.

1.2 Table FIG. 2 is a diagram showing a table stored in the spectrocolorimeter of the first embodiment.

  A table 1200 illustrated in FIG. 2 is a relationship table that is stored in the storage unit 1066 and defines the relationship between the temperature of the light emitting circuit 1061 and the light emission time of the light source 1060. The five light emission times “85 μsec” and “ Including 80 μsec, “75 μsec”, “65 μsec”, and “60 μsec”, the five temperatures are “10 ° C. or lower”, “10-15 ° C.”, “15-20 ° C.”, “20-35 ° C.”, and “35 ° C. or higher”. including. “10 ° C. or less”, “10-15 ° C.”, “15-20 ° C.”, “20-35 ° C.” and “35 ° C. or more” correspond to “85 μsec”, “80 μsec”, “75 μsec”, “65 μsec” and “60 μsec”, respectively. To do. The table 1200 may be replaced with a table including 4 or less or 6 or more temperatures corresponding to 4 or less or 6 or more emission times each including 4 or less or 6 or more emission times. The table 1200 is defined such that the light emission time increases as the temperature decreases.

  Instead of the table 1200, one light emission time corresponding to an arbitrary temperature may be stored in the storage unit 1066.

1.3 Temperature Dependence of Light Emission Rate FIG. 3 is a graph illustrating changes in the light emission amount of a light source according to the temperature of the light emission circuit when the light source is a xenon tube.

  As illustrated in FIG. 3, the amount of light emitted from the light source 1060 decreases as the temperature of the light emitting circuit 1061 decreases. The amount of light emitted from the light source 1060 decreases as the temperature of the light emitting circuit 1061 decreases. The loss inside the capacitor increases because the tan δ of the capacitor increases as the temperature of the capacitor provided in the light emitting circuit 1061 decreases. Because. The change in the amount of emitted light when the temperature changes by 5 ° C. may be 10% or more of the amount of emitted light at 25 ° C., and becomes particularly large on the low temperature side.

  For this reason, referring to the table 1200 defined so that the light emission time of the light source 1060 becomes longer as the temperature of the light emission circuit 1061 becomes lower, a correction process in which the light emission time of the light source 1060 becomes longer as the temperature of the light emission circuit 1061 becomes lower. If performed, the decrease in the amount of light emitted from the light source 1060 is compensated by the extension of the light emission time of the light source 1060, the intensity of the integrated signal 1160 is maintained, and the performance of the spectrocolorimeter 1000 such as a decrease in the S / N ratio is improved. Reduction is suppressed.

1.4 White Calibration Procedure FIG. 4 is a flowchart illustrating the white calibration procedure performed in the spectrocolorimeter of the first embodiment.

  In the following, it is assumed that when white calibration is performed, the integration signal 1160 is the first integration signal, and the temperature detected by the temperature detector 1067 is the first temperature.

  In step S101, white calibration is started.

  In step S102 following step S101, the temperature detector 1067 detects the temperature.

  In step S103 following step S102, the control unit 1120 sets the first light emission time. In setting the first light emission time, the table 1200 is referred to, and the five temperatures are “10 ° C. or lower”, “10-15 ° C.”, “15-20 ° C.”, “20-35 ° C.”, and “35 ° C. or higher”. The first coincidence temperature, which is the temperature that coincides with the first temperature, is selected, and the first coincidence temperature is selected from the five light emission times “85 μsec”, “80 μsec”, “75 μsec”, “65 μsec”, and “60 μsec”. The first corresponding light emission time which is the light emission time corresponding to is selected, and the first corresponding light emission time is set as the first light emission time.

  When one light emission time corresponding to an arbitrary temperature is stored in the storage unit 1066, the one light emission time is set as the first light emission time.

  In step S104 following step S103, the spectrocolorimeter 1000 performs a measurement operation. In the measurement operation, the sample 1020 becomes a white calibration plate, and the control unit 1120 controls the light emitting circuit 1061 so that the light source 1060 emits the illumination light 1040 for the first light emission time. Since the table 1200 is defined such that the light emission time becomes longer as the temperature becomes lower, the first light emission time becomes longer as the first temperature becomes lower.

  In step S105 following step S104, the control unit 1120 determines whether or not the first integration signal is within an allowable range. When it is determined in step S105 that the first integrated signal is within the allowable range, the control unit 1120 executes step S106 following step S105. When determining in step S105 that the first integrated signal is not within the allowable range, the control unit 1120 executes steps S107 to S113 subsequent to step S105.

  In step S106, white calibration is completed.

  In step S107, control unit 1120 determines whether or not the number of measurements is less than N, which is the reference number of measurements. When it is determined that the number of times of measurement is less than N times, the control unit 1120 executes steps S108 to S110 subsequent to step S107. When it is determined that the number of measurements is N or more, the control unit 1120 executes step S111 to step S113 following step S107.

  When the number of measurements is less than N, it is estimated that the reason why the intensity of the reflected light 1041 from the white calibration plate is not within the allowable range is not the deterioration of the light source 1060 but the individual difference of the light sources 1060. On the other hand, when the number of times of measurement is N or more, it is estimated that the cause that the intensity of the reflected light 1041 from the white calibration plate is not within the allowable range is not the individual difference of the light sources 1060 but the deterioration of the light sources 1060. Therefore, according to step S107, when it is estimated that there is an individual difference of the light source 1060, the first correction process suitable for the case where there is an individual difference of the light source 1060 in steps S108 to S110 is performed. When it is estimated that 1060 degradation exists, the second correction process suitable for the case where the degradation of the light source 1060 exists in steps S111 to S113 is performed. The first correction process and the second correction process are different from each other.

  In step S108, control unit 1120 determines whether the first integrated signal is smaller than the lower limit of the allowable range or larger than the upper limit of the allowable range. When determining in step S108 that the first integrated signal is smaller than the lower limit of the allowable range, the control unit 1120 executes step S109 following step S108. When determining in step S108 that the first integrated signal is larger than the upper limit of the allowable range, the control unit 1120 executes step S110 following step S108.

  In step S109, the control unit 1120 corrects the table 1200. In the correction of the table 1200 in step S109, the five light emission times included in the table 1200 are corrected so that the five light emission times after correction are longer than the five light emission times before correction. For example, the five light emission times are uniformly extended by 5 μsec. The correction amounts of the five light emission times may be different from each other.

  In step S110, the control unit 1120 corrects the table 1200. In the correction of the table 1200 in step S110, the five light emission times included in the table 1200 are corrected so that the five light emission times after correction are shorter than the five light emission times before correction.

  According to steps S109 and S110, the correction processing in which the five light emission times after correction become longer as the first integrated signal becomes smaller is performed for the five light emission times.

  After step S109 is executed, step S102 is executed again. Moreover, after step S110 is performed, step S102 is performed again. Thus, the first correction process is repeated until the first integrated signal is within the allowable range.

  In step S111, control unit 1120 determines whether or not table 1200 has been corrected. If it is determined in step S111 that the table 1200 has not been corrected, the control unit 1120 executes step S112 following step S111. When it is determined in step S111 that the table 1200 has been corrected, the control unit 1120 executes step S113 following step S111.

  In step S112, the control unit 1120 corrects the table 1200. In the correction of the table 1200 in step S112, the five light emission times included in the table 1200 are corrected so that the five light emission times after correction are longer than the five light emission times before correction. Thus, when the table 1200 is not corrected even though the number of measurements is greater than N, the table 1200 is corrected.

  In step S113, control unit 1120 causes display unit 1068 to display an error. The error display is a warning display indicating that the light source 1060 has deteriorated. Thereby, when it is determined that the number of measurements is N or more and the number of corrections is 1 or more, an error display is performed. When it is determined that the number of measurements is N or more and the number of corrections is one or more, it is estimated that the light source 1060 is deteriorated. Therefore, the error display is estimated that the light source 1060 is deteriorated. To be done. The standard number of times of one time may be replaced with the number of times of another standard.

  After step S112 is executed, step S102 is executed again.

1.5 Measurement Procedure FIG. 5 is a flowchart illustrating a measurement procedure performed in the spectrocolorimeter of the first embodiment.

  Hereinafter, it is assumed that when measurement is performed, the integration signal 1160 is the second integration signal, and the temperature detected by the temperature detector 1067 is the second temperature.

  In step S121, color measurement is started.

  In step S122 following step S121, the temperature detector 1067 detects the temperature.

  In step S123 following step S122, control unit 1120 sets a second light emission time. In setting the second light emission time, the table 1200 is referred to, and the five temperatures are “10 ° C. or lower”, “10-15 ° C.”, “15-20 ° C.”, “20-35 ° C.” and “35 ° C. or higher”. The second coincidence temperature, which is the temperature that coincides with the second temperature, is selected from “85 μsec”, “80 μsec”, “75 μsec”, “65 μsec”, and “60 μsec”, which are the five light emission times. The second corresponding light emission time which is the light emission time corresponding to is selected, and the second corresponding light emission time is set as the second light emission time.

  In step S124 following step S123, the spectrocolorimeter 1000 performs a colorimetric operation. In the color measurement operation, the control unit 1120 controls the light emitting circuit 1061 so that the light source 1060 emits the illumination light 1040 for the second light emission time. Since the table 1200 is defined such that the light emission time becomes longer as the temperature becomes lower, the second light emission time becomes longer as the second temperature becomes lower.

  In step S125 following step S124, control unit 1120 determines whether or not the second integration signal is saturated. When it is determined in step S125 that the second integrated signal is not saturated, the control unit 1120 executes step S126. When it is determined in step S126 that the second integrated signal is saturated, control unit 1120 executes step S127.

  In step S126, the arithmetic processing unit 1190 calculates a colorimetric value from the second integrated signal, and the colorimetry is completed.

  In step S127, the control unit 1120 causes the display unit 1068 to display an error. The error display is a warning display prompting calibration.

  According to the spectrocolorimeter 1000 of the first embodiment, since the intensity of the illumination light 1040 is not changed and the colorimetric value of the light source 1060 is not corrected, the occurrence of an error in the colorimetric value is suppressed, In the spectrocolorimeter 1000, the control is prevented from becoming complicated. Further, since a mechanism for monitoring the intensity of the illumination light 1040 is not required, the structure of the spectrocolorimeter 1000 is suppressed from becoming complicated.

  Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that countless variations that are not illustrated can be envisaged without departing from the scope of the present invention.

  The reflection / transmission characteristic measurement apparatus according to the present invention can be used in the measurement field for measuring reflection / transmission characteristics.

1000 spectrophotometer 1060 light source 1061 light emission circuit 1062 photodetector 1063 integrator 1064 A / D converter 1065 control calculation unit 1066 storage unit 1067 temperature detector 1068 display unit 1190 calculation processing unit

Claims (4)

A light source that emits illumination light applied to the sample;
A light-emitting circuit that supplies the light source with the power required to emit the illumination light;
A photodetector that outputs a detection signal corresponding to reflected light generated when the sample reflects the illumination light or transmitted light generated when the sample transmits the illumination light;
An integrator that integrates the detection signal and outputs an integration signal;
A storage unit for storing at least one emission time;
When the white calibration is performed, the integration signal is the first integration signal, and when the measurement is performed, the integration signal is the second integration signal. Is performed, the light source is controlled so that the light source emits the illumination light only for a first light emission time included in the at least one light emission time, and the corrected after the first integrated signal becomes smaller Correction processing for increasing at least one light emission time is performed on the at least one light emission time. (2) When the measurement is performed, the correction process is performed for the second light emission time included in the at least one light emission time. A control unit that controls the light emitting circuit so that a light source emits the illumination light;
An arithmetic processing unit that calculates reflection / transmission characteristics of the sample from the second integration signal;
A reflection / transmission characteristic measurement apparatus comprising: A temperature detector for detecting a temperature inside the reflection / transmission characteristic measuring device;
The at least one light emission time is a plurality of light emission times;
The storage unit further stores a plurality of temperatures respectively corresponding to the plurality of light emission times,
When the white calibration is performed, the control unit detects the internal temperature detected by the temperature detector as a first temperature, and the internal temperature detected by the temperature detector when the measurement is performed. When it is assumed that the temperature is the second temperature, (1) when the white calibration is performed, a first matching temperature that is a temperature matching the first temperature is selected from the plurality of temperatures. Then, a first corresponding light emission time that is a light emission time corresponding to the first coincidence temperature is selected from the plurality of light emission times, and the first corresponding light emission time is set as the first light emission time, (2) When the measurement is performed, a second coincidence temperature that is a temperature that coincides with the second temperature is selected from the plurality of temperatures, and a light emission time corresponding to the second coincidence temperature is selected from the plurality of light emission times. Select a second corresponding light emission time which is Reflection / transmission characteristic measuring apparatus according to claim 1, the corresponding light emission time and the second light emission time. The correction process is a first correction process,
The storage unit further stores the number of measurements that is the number of times the measurement has been performed,
When the white calibration is performed, the control unit performs the first correction process when it is determined that the first integral signal is not within an allowable range and the number of measurements is less than a reference number of measurements, 3. A second correction process different from the first correction process is performed when it is determined that the first integration signal is not within the allowable range and the measurement count is equal to or greater than the reference measurement count. The reflection / transmission characteristic measuring apparatus according to 1. A display unit;
The storage unit further stores a measurement count that is the number of times the measurement has been performed and a correction count that is the number of times that the correction processing has been performed,
When the white calibration is performed, the control unit causes the display unit to display an error when it is determined that the measurement count is equal to or greater than a reference measurement count and the correction count is equal to or greater than a reference correction count. The reflection / transmission characteristic measuring apparatus according to any one of claims 1 to 3.

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