JPH02156140A - Sparkling look measurement for metallic painted film - Google Patents

Abstract

PURPOSE:To enable continuous measurement of a sparkling look (shining look) of a metallic painted film in a short time by performing an evaluation by scattering of the results of measuring quantity of reflected diffusion light measured at a plurality of points to determine the sparkling look quantitatively in a level close to a human visual evaluation. CONSTITUTION:An optical probe 1 is set on the surface of a plate 8 to be measured and then, when a start button is depressed, light is irradiated from a projector 2 and reflected light thereof is received with a photo detector 3. The light received is converted into an electrical signal and after converted 9 into digital from analog, it is taken into a CPU 10. An output signal is outputted to a motor driver 11 from the CPU 10 to rotate a step motor 7 for a fixed time. As a result, a substrate 4 moves 2mm, for instance. This operation is normally repeated more than nine times. Then, when a select switch on a control panel is depressed, a mean of a quantity of reflected light and a data of a standard deviation thus far taken are shown on an LCD display sec tion 14 or printed out on a printer 13.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method and apparatus for objectively and quantitatively measuring the sparkle feel of a metallic coating film.

(Conventional technology and its problems) Conventionally, the optical properties of metallic coatings are as follows.

Brightness (whiteness), directionality (flip-flop properties), sparkle (glitter), etc. are evaluated, and currently all are qualitatively judged by human visual observation. Recently, the brightness and directionality of metallic paint films have been measured quantitatively using spectrophotometers and variable angle glossy needles, but no effective measurement method has been found for the sparkle feel. In the past, we measured the amount of diffusely reflected light using a variable-angle glossy needle, and calculated the sparkling effect value from a certain relational expression.
However, the amount of diffusely reflected light had to be continuously measured in an arbitrary angular range, and the measurement required a large amount of time.

In addition, in recent years, aluminum pigments for metallic paints have become more diverse and diverse, and it has become increasingly important to quantify the sparkle feel, which varies subtly due to particle size distribution, shape, surface treatment, etc., in a manner similar to human visual evaluation. It has become difficult. In particular, when selecting and evaluating aluminum pigments, sparkle feeling tends to be considered important.

(Means for Solving the Problems) In the process of researching the reflection characteristics of metallic coatings using a three-dimensional optical system, the present inventor discovered that although the diffuse reflection characteristics are almost similar, a sparkle effect is evident. When measuring the amount of diffusely reflected light using different samples and varying the beam diameter of the incident light, it was found that when the beam diameter was 211 mm or less, the amount of light varied greatly depending on the measurement area of the metallic coating even if the incident angle and acceptance angle were constant. , this variation (standard deviation)
It was found that the size of the sparkle has a large relationship with the sparkle feeling. That is, it has been found that the sparkle feeling is related to the intensity of specularly reflected light from the individual aluminum pigments oriented within the metallic coating film and its fine distribution.

The angle of incidence for measuring the intensity and distribution of this specularly reflected light is preferably set at 45° to 60° with respect to the surface of the coating film to be measured due to the orientation of the aluminum pigment within the metallic coating film. The angle is set at approximately 45° in accordance with JIS Z8722 "Measurement method for reflective objects". On the other hand, the acceptance angle was set to 55°±5°, but at 45° to 50°, the specularly reflected light from the clear film formed on the surface of the metallic coating enters as noise, so in this area, the metallic coating It is not possible to capture the delicate reflection characteristics from the aluminum pigment in the film, and the amount of reflected light gradually decreases at angles over 60 degrees, which is not desirable.The fewer the measurement points, the greater the measurement error. Therefore, 10
It is desirable to measure at more than one location.

(Example) An example of the present invention will be described in detail based on the drawings. 1st
At the top of the figure is an optical probe 1, in which a light projector 2 and a light receiver 3 are attached to a substrate 4. The board 4 can be moved along slide rails 5. Furthermore, a ball screw 6 is incorporated into this substrate 4, and the ball screw 6 is connected to a small step motor 7.

The light emitter 2 and the light receiver 3 are installed at angles of 45° and 55° with respect to the surface of the plate 8 to be measured, respectively.

When the optical probe 1 is set on the surface of the plate 8 to be measured and a start button (not shown) is pressed, light is emitted from the light projector 2 and the reflected light is received by the light receiver 3. The received light is converted into an electrical signal, and the A/D converter 9 converts the light into an electrical signal.
After being D-converted, it is taken into the CPU (ijl calculation/control unit) 10. Thereafter, an output signal is output from the CPU 10 to the motor driver 11, causing the step motor 7 to rotate for a certain period of time. As a result, the substrate 4 moves 2Ill1m, is irradiated with light from the light projector 2 again, and a signal corresponding to the amount of reflected light is taken into the CPLIIO. This action is usually 1
Repeated 0 or more times.

Next, when you press the select switch C (not shown) on the operation panel, the average value and standard deviation data of the amount of reflected light captured up to that point will be displayed on the LCD display section 14 or printed out on the printer 13. Ru.

Figure 2 shows an example in which the standard deviation (sparkle feeling parameter) of the amount of reflected light (brightness parameter) measured based on the present invention is compared with human visual evaluation. The results match very well.

Figure 3 is a graph showing the actual measured values at that time.6 (Effects of the invention) According to the present invention, the sparkle feeling of metallic paint films, which has been difficult to measure up to now, can be evaluated visually by humans. It can be quantified in a close manner and can be measured continuously in a short period of time. This makes it easy to select and evaluate aluminum pigments, etc., which greatly affect the design of metallic paints, which is extremely effective in designing metallic paints.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the operation including the optical probe and other devices. l...Optical probe, 2... Emitter, 3... Light receiver, 4... Board, 5... Slide rail, 6... Ball screw, 7... Step/motor, 8... ... Board to be measured, 9... A/D converter, l
O...CPU (calculation/control unit), 11...Motor driver, 12...Light source driver, 13...
Printer 14...LCD display section. FIG. 2 is a correlation diagram showing the relationship between the measurement results and visual evaluation based on the present invention, and FIG. 3 is a graph of the actual measured values.

Claims (1)

[Claims] A light projecting part that irradiates a laser beam with a beam diameter of 0.1 to 2 mmφ at a certain angle of incidence to the surface of a coating part to be measured of a metallic coating film, and a In a three-dimensional optical system equipped with a light receiver that measures the intensity of diffusely reflected light in a region at an angle different from the incident angle with respect to the surface of the coating portion, A method for measuring the sparkle feeling of a metallic coating film, characterized in that the sparkle feeling of a metallic coating film is evaluated based on the variation in the light intensity measurement results of the diffusely reflected light measured at a plurality of locations at intervals.