FR2635869A1 - METHOD AND DEVICE FOR SIMULTANEOUS DETERMINATION OF DIFFERENCES IN BRIGHTNESS AND COLOR - Google Patents

Abstract

Method for the simultaneous determination of differences in gloss and color on enamelled, varnished or similar flat objects having undergone a surface treatment, using semiconductor sensors sensitive to the spectrum, independently of the intensity, sensors determining the barycenter of polychromatic radiation in ranges between 350 nm and 750 nm, and further using polychromatic light sources and laser light sources, characterized in that sample 7 is alternately irradiated with laser light and polychromatic light and that the reflected radiation received by the semiconductor sensor 5 is converted into electrical signals and brought to an operating unit 6.

Description

The invention relates to a method and device for simultaneous determination.

  differences in gloss and color applied for the assessment of the quality of varnished and enamelled surfaces as well as in the research and development of these fields. It is currently not possible to assess brightness and color simultaneously. The processes

  indicated below allow, by overcoming the problems

  mes, to carry out the measurement of the individual quantities which are the brightness and the color. The determination of color differences on enamelled, varnished, or similarly pretreated products is only resolved in practice very incompletely. The possibility of describing the color by remission curves is certainly feasible, but it is however already linked, in the research laboratory, to a high cost in material and time and it is not feasible under the conditions

  of production (Bayer Enamel Manual, Dr. Kyri, 1974).

  A second possibility is to determine

  a color with a device with three filters. Different-

  However, considerable reductions occur here in the case of very saturated red and purple colors (Manual

from Bayer enamel, Dr. Kyri 1974).

  Even more brilliance than color is influenced by subjective sensations. The gloss is usually measured by the reflection of a ray

  bright, by measuring the amount of light reflected

  shits. The light rays are then reflected symmetrically.

  only with respect to a fictitious perpendicular and

  at an angle identical to the incident angle.

  Many factors interfere with the measurement of

  shine, so for example ripple or micro-

  corrugation of enamelled, varnished or similar surfaces

  res, which causes a diffuse dispersion or a modified angle of reflection. There are currently only a few devices for which, for example, a cross or open rings of different sizes are reflected in the surface to be checked. The exploitation of the results

  is done visually in both cases.

  The aim of the invention is to create a method and a device making it possible to simultaneously determine the differences in gloss and color under conditions

  for practical use.

  The object of the invention makes it possible to measure simultaneously

  differences in gloss and color by means of sensors and optical components

electronics and electronics.

  According to the invention, the problem is solved by the fact that the object to be checked passes over a device consisting of a laser light source, a polychromatic light source, a modulator, a sensor sensitive to the intensity and of a spectrum-sensitive sensor, independently of the intensity, and of an operating unit, the light from the polychromatic source, diffusely reflected, and the light reflected from the laser light source being operated by the sensor and displayed by the operating unit. In this device, the value of the corrugations or the roughness having a

  influence on the diameter of the sensor optics.

  According to another characteristic of the invention, there is one or more semiconductor sensors, for the purpose of irradiating the sample to be checked, the direction of the laser beam reaching the surface of the sample at an angle of 45 and that of the polychromatic light source reaching this surface perpendicularly. According to another characteristic of the invention, a laser light source and a polychromatic light source are connected using a modulator

  to allow alternative irradiation.

  Various other features of the invention

  emerge from the detailed description which follows.

  An embodiment of the subject of the invention is shown: example title not

limiting on the drawing.

  The single figure is a diagram of the device of the invention. In a production operation, varnished coating pieces intended for refrigerators move, suspended on a transport chain, in front of a sample control device 7 intended for the simultaneous determination of differences in gloss and color. A laser known in the trade under the name of Helius neon 1 then emits a light ray 0 of 0.25 mm which is reflected in 4 and picked up by the optics of a

  sensor 5. The sensor 5 capable of determining the bar-

  rycentre of polychromatic radiation in ranges between 350 and 750 mm is composed of two layers

  photosensitive semiconductors placed one on the other

  be and is able to convert the incident light radiation 4 into an intensity signal and into another signal which is independent of the first, signal representing the

  spectral barycenter of radiation. A 3 polychro lamp

  matic tungsten simultaneously emits light which

  diffuse reflection is picked up by the same sensor 5.

  A modulator 2 having the shape of a diaphragm of

  quence 80 Hz permanently interrupts the laser beam,

  so that only short parts of the ray are reflected

  chies to the sensor which determines the intensity which, once exploited, provides a value for the gloss of varnished surfaces. During breaks, during which no reflected laser beam can reach the sensor, the latter picks up the diffuse reflected radiation from the polychromatic lamp. We then determine the barycenter of the

  radiation, which constitutes a v-their of color.

  A predetermined measurement tolerance provides a signal if the brightness or color is outside the range

of tolerance.

  The color differences of different samples and processing conditions are checked to keep within the color differences

  and to obtain color stability.

  An apparatus has been built for this purpose in the laboratory, an apparatus on the control surface of which the sample to be checked is applied 7. A polychromatic lamp 3 is placed perpendicular to the sample and a laser 1 is placed at 45. The

  two light sources emit a corresponding light

  dante which alternately touches the optics of a sensor 5, via a modulator 2, and which is used in 6. This process makes it possible to obtain in very little

  time values of brightness and color.

Claims (3)

  1. Method for the simultaneous determination of differences in gloss and color on flat enamelled, varnished or similar objects having undergone a surface treatment, using semiconductor sensors sensitive to the intensity and sensitive to the   spectrum, regardless of intensity, sensors determined   inducing the barycenter of polychromatic radiation in ranges between 350 nm and 750 nm, and also using polychromatic light sources and   laser light sources, characterized in that the exchange   tillon (7) is alternately irradiated with laser light and polychromatic light and the reflected radiation received by the semiconductor sensor (5) is converted into electrical signals and brought to a unit operating (6).   2. Device for the simultaneous determination of   differences in gloss and color for making   tion of the method according to claim 1, characterized in   what we have one or more semi sensors   conductors (6), in order to irradiate the sample (7) to be checked, in that the direction of the laser beam reaches the surface of the sample (7) at an angle of and that of the light source polychromatic   reaches this surface perpendicularly.   3. Device according to claim 2, character-   rised in that, in order to irradiate alternately by a laser light source and a polychromatic light source, the latter are connected using a modulator.