JPH0634440A - Colorimeter - Google Patents

Abstract

(57) [Summary] [Objective] An accurate measurement value is obtained by compensating for the difference in the characteristics in the intermediate state due to the deviation of the characteristics of the optical system, the machine difference, the temperature, the deviation of the wavelength of the irradiation light, and the like. [Configuration] Different calibration plates 24A to 24E are measured in advance, the sensor output value at that time and the measured value are stored as calibration values, and the sensor output value when measuring the measurement sample 14 is calibrated before and after that. A linear interpolation calculation is performed between the values to obtain a measurement value in which the intermediate characteristic is finely corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colorimeter, and more particularly, to a colorimeter capable of obtaining an accurate measured value by performing a correction suitable for the characteristics of a photometry section.

[0002]

2. Description of the Related Art Conventionally, reflected light when a measurement sample is irradiated with light from a light source is dispersed by a spectroscopic means, and this is received by a light receiving element array and photoelectrically converted to obtain a sensor output. There is a colorimeter in which a signal processing unit including a microcomputer performs color calculation to obtain a final measured value.

Here, normally, a sensor output obtained from an actual measurement sample is obtained by obtaining a calibration value from the sensor output when the amount of light is zero and the sensor output when a white plate is placed at the position of the measurement sample. The measurement value corresponding to the sensor output is obtained from the straight line connecting the two points by linear interpolation calculation on the assumption that it has a proportional relationship with the state of the two points.

[0004]

As described above, in the conventional colorimeter, the sensor output in the standard two states is calculated,
The sensor output obtained from the measurement sample is obtained as a measurement value on the assumption that a proportional relationship is maintained between the two states, but in reality, the mechanical deviation of the optical system, the temperature, the irradiation light However, the proportional relationship is not always maintained accurately due to the wavelength shift and the like.

Further, even with the same colorimeter, the measured values may change due to aging, etc., and even with a colorimeter manufactured with the same specifications, the results obtained by measuring the same measurement sample may be different. Since the characteristics of the intermediate state between the two states are different for each colorimeter, there is a problem that different measurement values are naturally obtained.

The present invention has been made in view of the above-mentioned problems of the prior art, and copes with the mechanical deviation of the optical system, temperature, deviation of the wavelength of the irradiation light, secular change, and characteristics that vary from device to device. Therefore, it is an object of the present invention to provide a colorimeter capable of performing accurate measurement by performing a correction suitable for the characteristics of the photometric unit.

[0007]

According to the present invention, there is provided a photometric unit for photoelectrically converting a reflected light when a measurement sample is irradiated with light from a light source into a sensor output, and a sensor output from the photometric unit. And a signal processing unit that outputs a measurement value based on the above-mentioned, and at least three calibration plates having different reflectances that can be sequentially and selectively arranged at the position of the measurement sample are provided. At the same time, the signal processing unit stores a calibration sensor output value obtained by the photometric unit for each calibration plate when the calibration plate is placed at the position of the measurement sample, and a calibration value storage that stores the corresponding calibration measurement value. Means for comparing the sensor output value input at the time of irradiation of the measurement sample with the calibration sensor output value stored in the calibration value storage means, and the calibration sensor output value before and after the sensor output value on the XY coordinates and the pair And correcting means for obtaining a measured value by linear interpolation from a straight line passing through the two points of the calibration measurement values, by providing is to achieve the above object.

In addition, the plurality of calibration plates are rotatable plates that are rotatable in a plane parallel to the irradiated surface at the position of the measurement sample.
A position for mounting the sample at a proper interval in the circumferential direction, providing a window for sample measurement without mounting a calibration plate on the rotary plate, detecting the rotational position of the rotary plate, and outputting the signal to the calibration value storage means. A detector may be provided.

[0009]

In the present invention, a large number of calibration sensor output values and corresponding calibration measurement values are obtained with three or more calibration plates, and the obtained sensor output values are used as actual sample measurement values. , It is possible to obtain an accurate measured value by performing a linear interpolation calculation between the corresponding calibration values and performing a correction according to the characteristics of the photometric unit.

According to the present invention, the calibration plate is mounted on the rotary plate and is quickly switched, and the rotational position of the rotary plate is detected by the position detector, and the calibration value storage means of the signal processing unit is detected. The calibration value can be easily obtained in conjunction with.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

The colorimeter 10 according to this embodiment includes a light source 12
From the light receiving element (array) 16 for photoelectrically converting the reflected light when the measurement sample 14 is irradiated with the light from the light source, and a sensor output from the light measuring portion 18 that outputs a sensor output through the A / D converter 17. A signal processing unit 20 that calculates based on the output and outputs a measurement value is attached to the rotary plate 22 at appropriate intervals in the circumferential direction thereof, and in accordance with the rotation of the rotary plate 22, the front surface of the measurement sample 14 is sequentially positioned. Five calibration plates 24A to 24E having different reflectances that can be selectively arranged
It is composed of and.

The signal processing unit 20 includes the calibration plate 24.
Calibration value storage means 26 for storing calibration sensor output values obtained from the photometric unit 18 for each calibration plate and calibration measurement values corresponding thereto when A to 24E are placed at the position of the measurement sample 14, and measurement. The sensor output value input at the time of irradiating the sample 14 is compared with the calibration sensor output value stored in the calibration value storage means 26, and the calibration sensor output values before and after the sensor output value on the XY coordinates and corresponding values are compared. Correction means 28 for obtaining a measurement value by linear interpolation from a straight line passing between two points of the calibration measurement value.

The rotating plate 22 is rotatable on the front surface of the measurement sample 14 in a plane parallel to the surface to be irradiated, and has a sample measurement window 24F to which a calibration plate is not attached.

Further, the rotary position of the rotary plate 22 is detected by facing the rotary plate 22, and accordingly, from the rotary position,
A position detector 30 is provided which detects any of the calibration plates 24A to 24E or the window 24F at the position of the measurement sample 14 and outputs the signal to the calibration value storage means 26. Reference numeral 32 in FIG. 1 denotes a calibration plate driving stepping motor for rotationally driving the rotary plate 22. The calibration plate 24E is a white plate.

The calibration value storage means 26 corresponds to the detection signal of the position detecting device 30, and the corresponding calibration plates 24-2.
Calibration sensor output acquisition unit 26A that acquires the sensor output value during 4E measurement, and calibration value storage unit 26 that stores this calibration value
It is composed of B and. The calibration value storage unit 26B stores previously known calibration values of the calibration plates 24A to 24E or is manually input. The sensor output values a to e and the calibration values A to E in FIG. 3 correspond to the calibration plates 24A to 24E.

The correction means 28 includes the sensor output acquisition unit 2
The sensor output acquisition unit by the correction data creation unit 28A that calculates the correction data based on the sensor output from 1 and the calibration value stored in the calibration value storage unit 26B, and the correction data from the correction data creation unit 28A. And a correction unit 28B that corrects the sensor output from the sensor 21. The output (measurement value) of the correction unit 28B is displayed by the display means 34 such as a CRT or a printer.

Next, the measuring process by the colorimeter 10 according to the above embodiment will be described.

First, a stepping motor 3 for driving the calibration plate
The rotary plate 22 is driven by 2 and the calibration plates 24A to 24E are sequentially positioned in front of the measurement sample 14, and the light source 1 is supplied each time.
2 irradiates the calibration plates 24A to 24E.

At this time, the calibration sensor output acquisition unit 26A takes in the calibration sensor output value obtained by the light receiving element 16 based on the signal of the position detection device 30, and this signal is stored in the calibration value storage unit 26B and at the same time. , Calibration plates 24A-24E
A calibration value known in advance corresponding to the above is also stored corresponding to the sensor output value. The relationship between the sensor output value and the calibration value when measuring the calibration plate is as shown in FIG.

Next, a stepping motor 3 for driving the calibration plate
2 is driven to position the window 24F of the rotary plate 22 on the front surface of the measurement sample 14. The measurement sample 14 is irradiated with the light from the light source 12 at this time, and the reflected light is photoelectrically converted by the light receiving element 16 to be a sensor output. The sensor output acquisition unit 21 takes in the sensor output according to the window 24F detection signal from the position detection device 30, and outputs the signal to the correction data creation unit 28A,
And sends it to the correction unit 28B.

The sensor output signal sent to the correction data creating section 28A is compared with the correction data composed of the calibration sensor output value and the calibration measurement value stored in the calibration value storage means 26, and the input sensor output is obtained. Between the calibration sensor output values before and after the value, that is, the target section is determined as shown in FIG.

Further, in the correction unit 28B, the calibration sensor output value and the calibration measurement value at both ends of the determined target section are taken out from the correction data, and the two values on the XY coordinate of the data are extracted.
A straight line passing through the points is obtained, and a linearly interpolated line is used to calculate a measurement value corresponding to the sensor output value.

With this arrangement, conventionally, as shown by the broken line in FIG. 3, the measurement value obtained by the linear interpolation calculation on the straight line between the sensor output maximum value and zero is determined by the optical system of the apparatus. Due to mechanical deviation, temperature, wavelength deviation of irradiation light, aging of the device, etc.
An accurate measurement value can be obtained by performing a fine correction according to the characteristics of the photometric unit 18. As compared with the broken line in FIG. 3, accurate measurement values are obtained by the amount of deviation Y.

Further, in this embodiment, a plurality of calibration plates 24A are used.
24E are attached to the rotary plate 22, and this is driven by the calibration plate driving stepping motor 32, and at the same time, the position detecting device 3
Since the position of the calibration plate is detected by 0, the calibration value can be quickly set in the calibration value storage means 26 of the signal processing unit 20.

Therefore, the measurement work by the colorimeter 10 can be easily and surely performed.

In the above embodiment, the rotary plate 22 is provided with five calibration plates 24A to 24E, but the present invention is not limited to this, and at least the calibration plates have different reflectances. It is also possible to attach three slides to a slide plate that reciprocates linearly, for example.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a colorimeter according to the present invention.

FIG. 2 is a plan view showing a rotary plate to which a calibration plate is attached in the above embodiment.

FIG. 3 is a diagram showing a relationship between a calibration value, a sensor output value, and a measured value when measuring with the colorimeter of the embodiment.

[Explanation of symbols]

 10 ... Colorimeter 12 ... Light source 14 ... Measurement sample 16 ... Light receiving element 18 ... Photometric unit 20 ... Signal processing unit 22 ... Rotating plate 24A-24E ... Calibration plate 24F ... Window 26 ... Calibration value storage means 26A ... Calibration sensor output acquisition unit 26B ... Calibration value storage unit 28 ... Correction means 28A ... Correction data creation unit 28B ... Correction unit 30 ... Position detection device 32 ... Calibration plate driving stepping motor 34 ... Display means

Claims (2)

[Claims] 1. A photometric unit that photoelectrically converts a reflected light when a measurement sample is irradiated with light from a light source by a light receiving element to obtain a sensor output, and a measured value calculated by a sensor output from the photometric unit. In a colorimeter including a signal processing unit for outputting, at least three calibration plates having different reflectances that can be sequentially arranged at the position of the measurement sample are provided, and the signal processing unit includes: Calibration value storage means for storing the calibration sensor output value obtained by the photometric unit for each calibration plate and the calibration measurement value corresponding thereto when the calibration plate is placed at the position of the measurement sample, and at the time of irradiation of the measurement sample Between the input sensor output value and the calibration sensor output value stored in the calibration value storage means, and between the two points of the calibration sensor output value before and after the sensor output value on the XY coordinates and the corresponding calibration measurement value. Through And a correction means for obtaining a measured value from a straight line obtained by linear interpolation. 2. The plurality of calibration plates according to claim 1,
At the position of the sample to be measured, a rotating plate rotatable in a plane parallel to the surface to be irradiated is attached at appropriate intervals in the circumferential direction, and a window for sample measurement is provided on the rotating plate without attaching a calibration plate. A colorimeter provided with a position detector that detects a rotational position of the rotary plate and outputs a signal thereof to the calibration value storage means.