JPS6212847B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to the long-term stability of a colorimeter that measures the color of an object by dividing it into XYZ. Conventional colorimetric devices have the disadvantage of large fluctuations in measured values due to temperature changes and the like. The outline will be explained next. FIG. 1 is an explanatory diagram of a conventional colorimetric device. Light from a light source 1 passes through a heat shielding filter 2 and a lens 3, becomes parallel light, and hits the sample 5 perpendicularly. The light diffusely reflected by the sample is received by the integrating sphere 4, and then
It is received by each XYZ light receiver 6, 7, and 8 and converted into electric current. Each current is voltage amplified by amplifiers 9, 10, and 11, respectively, and the value is displayed by a measuring section 12. For reference alignment, a reference plate with known XYZ values is fixed at the position of the sample 5, and the measurement unit 12 aligns it with the XYZ values. Although it is possible to measure the sample in this state, the measured value becomes inaccurate if there is a variation in the amount of light from the light source or a variation in temperature of the light receivers 6, 7, 8 and amplifiers 9, 10, 11. For this reason, methods have been adopted to reduce fluctuations in the amount of light from the light source and to reduce fluctuations due to temperature in the photoreceiver and amplifier, but it is still necessary to perform reference adjustment frequently when accurate measurements are required. A method that improves this stability is cross-illumination photometry. FIG. 2 is an explanatory diagram thereof. The light emitted from the light source 13 passes through the lenses 14 and 14', becomes a parallel beam, is reflected by the mirrors 15 and 15', and is reflected by the motor 16.
The specimen 19 and the reference plate 2
0 intermittently and is diffusely reflected. This light is captured by the integrating sphere 18, converted into photocurrent by the photodetector 21, and enters the measurement section 23. The position detector 22 determines whether the light beam is hitting the reference plate or the sample. That is, cross-illumination photometry is a method of measuring color based on the ratio of when the light hits the reference plate and when it hits the sample. Since this method requires two optical paths, it has the disadvantage of losing balance if a lens or the like on the optical path becomes dirty or changes. Another major drawback is that the reference plate must be fixed at all times. The present invention provides a color measurement device that can eliminate the drawbacks of the conventional methods described above and obtain stable measurement values. The invention will be explained by way of examples. In FIG. 3, the light emitted from the light source 31 is filtered through the heat shield filter 3.
The light beam passes through two lenses 33 and becomes a parallel beam of light, hits the sample 35 perpendicularly, is diffusely reflected, and is captured by the integrating sphere 34 . Furthermore, each of the X, Y, and Z receivers 36, 37,
The light is received at 38, becomes a photocurrent, passes through each amplifier 39, 40, and 41, and the signal switched by a switch 42 is converted into a digital quantity by an analog-to-digital converter 43, and then enters a microcomputer system 44. . Up to this point, it is the same as the conventional color measurement device, but in this device, the lens 33 and integrating sphere 34
Black disc (light-opaque) 48, integrating sphere 3 between
A white disk 49 is placed between the sample 4 and the sample 35. These two discs are connected and fixed to the shaft of a motor 47 and rotate at a constant speed. The black disk 48 and the white disk 49 are the fourth
In the shape shown in the figure, 48' and 49' are holes cut out to allow light to pass through, so if these two discs rotate at the same time at a constant speed, the three states A and B shown in Table 1 will occur. , C appears. In Table 1, A is a state in which the black disc 48 and the white disc 49 are on the optical path, and the optical path is cut off by the black disc so that no light is introduced into the integrating sphere. This is a state to know the deviation of the zero point of the photoreceiver and amplifier. B is black disk 4
8. This is a state in which the white disc 49 is located on the optical path and receives light reflected by the white disc without being blocked by the black disc. This state is used to check fluctuations in the overall output of the light source, receiver, amplifier, etc. C is a state in which the black disc 48 and the white disc 49 are located on the optical path, and the light beam is not blocked by both discs and the reflected light from the sample is received. The A, B, and C states are communicated to the microcomputer system by a position detector 50 corresponding to the black disk 48. The microcomputer system reads the XYZ values in each state, performs the calculations described below, and displays or prints the results.
Also, if necessary, it is possible to convert the XYZ values to other color systems. Next, the calculation formula will be explained according to the actual operation. When adjusting the reference: When the white reference plate with known XYZ values is fixed at the sample position and the reference adjustment switch 45 is turned on, the microcomputer system changes to state A,
Input each XYZ value in B and C. Then perform the next calculation. The input value of XYZ in state A is X _O Y _O Z _O The input value of XYZ in state B is X _B Y _B Z _B The input value of XYZ in state C is X _W Y _W Z _W , and the true value of the white reference plate is is stored in the microcomputer system in advance and its value is
If _T Y _T Z _T , then X _W −X _O ...White _reference plate input value after zero point correction X _B -X _O ... _{White disk} input value after zero point correction _O ) Similarly, for Y and Z, Y _T = K _Y (Y _W - Y _O ) Z _T = K _Z (Z _W - Z _O ), so the microcomputer system has K _X , K _Y , K _Z and X _B −X _O , Y _B −Y _O , Z _B −Z
_O , X _W −X _O , Y _W −Y _O , and Z _W −Z _O are memorized. During sample measurement: When the sample is fixed at the sample position and the measurement start switch 46 is turned on, the microcomputer system performs
Enter the value. The input value of XYZ in state A is X′ _O Y′ _O Z′ _O The input value of XYZ in state B is X′ _B Y′ _B Z′ _B The input value of XYZ in state C is X _S Y _S Z _S , Letting the true value of the sample be X _D , then X _D = K' _X (X _S - X' _O ) Since the relationship between K _X and _K ' You get a relationship. K' _{X = X B -X O / X ' B -X ' O K D} =Y _B -Y _O /Y' _B -Y' _O K _Y (Y _S -Y' _O ) Z _D =Z _B -Z _O /Z' _B -Z' _O K _Z (Z _S -Z' _O ) When measuring the sample, the microcomputer system calculates X _D Y _D Z _D. The microcomputer system displays or prints X _D Y _D Z _D and can also convert to other color systems if necessary. As explained above, by providing the black disk 48 and the white disk 49, the present invention measures the reflected light of the zero point and the white disk 49 every time a sample is measured, and changes the stability of the entire measurement system. If any change has occurred, the change is calculated, the sample measurement value is multiplied by a correction coefficient, and an operation is added to return the value to the value when there was no change. By doing so, it is possible to obtain a much more stable measurement value than with conventional methods. I can do it. In addition, in order to perform stable measurements with the conventional method, it was necessary to fix a white reference plate and adjust the reference value every time two or three measurement samples were measured, but with the present invention, this work is done using a white Since the rotation of the disc takes over, you only need to fix _{the white} reference plate once when the power is turned on and memorize the constants of _K It became. Fluctuations over time in the device according to the invention;
Table 2 shows a comparison of the fluctuations with the conventional system. To summarize the features of the color measuring device according to the present invention, zero adjustment is possible automatically, so no operation is required. For standard adjustment, all you need to do is fix the reference plate to the optical system and turn on the standard adjustment switch, and there is no need for subsequent calibration.As for stability, the white disk that rotates each time the sample is measured is automatically measured, and the When the value changed, significant improvement was achieved by correcting the measured value by the amount of change.

【table】

【table】 [Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a conventional colorimetric device, Fig. 2 is an explanatory diagram of cross-reflection photometry, Fig. 3 is an explanatory diagram of a device according to the present invention, and Fig. 4 is a diagram of the shape of a disk according to the present invention. It is a diagram. DESCRIPTION OF SYMBOLS 1... Light source, 2... Heat shielding filter, 3... Lens, 4... Integrating sphere, 5... Sample, 6... X receiver, 7... Y receiver, 8... Z receiver, 9... ...X
Amplifier, 10...Y amplifier, 11...Z amplifier,
12...Measuring unit, 13...Light source, 14...Lens, 15...Mirror, 16...Motor, 17...
...disc, 17'...notch hole, 18...integrating sphere, 1
9...sample, 20...reference plate, 21...light receiver,
22...Position detector, 23...Measurement section, 31...
Light source, 32...Heat filter, 33...Lens, 34...Integrating sphere, 35...Sample, 36...X
receiver for Y, 37... receiver for Y, 38... receiver for Z, 39... amplifier for X, 40... amplifier for Y, 41... amplifier for Z, 42... switch, 43
...Analog-digital converter, 44...Microcomputer system, 45...Reference adjustment switch, 46...Measurement start switch, 47...
Motor, 48...Black disc, 48'...Notch hole, 49...White disc, 49'...Notch hole, 50
...Position detector.

Claims (1)

[Claims] 1. In the integrating sphere optical system of a colorimeter, an integrating sphere with a light receiver is sandwiched between the light-impermeable disk, which has a partially cutout hole on the light entrance side, and a part on the light exit side. A color measurement device characterized by a mechanism in which a white disk having a notch hole is arranged, and both disks rotate at a constant speed about the same rotation axis.