JP7256166B2 - Paint surface observation method - Google Patents

Description

The present invention relates to a coating surface observation method.

Painted surfaces are broadly divided into solid paints and metallic paints. 2. Description of the Related Art Most visual inspections of painted surfaces, for example, visual inspections in automobile production lines, are carried out as visual inspections by human eyes.

Visual inspection catches flaws and foreign matter by irradiating the painted surface with light and visually checking the characteristic reflected light and scattered light from the flaw and foreign matter. In the visual inspection, in the case of a painted surface such as metallic, mica, or pearl (hereinafter referred to as "metallic painted surface"), the light from the painted surface includes not only reflected light and diffused light seen on solid painted surfaces, but also Reflected light and scattered light from each of the luster materials such as aluminum flakes and mica flakes contained in the coating film are included, and they become bright spots, and their effects when visually observing fine scratches, foreign matter, etc. cannot be ignored.

Japanese Patent Laid-Open No. 2002-100000 proposes a method for determining whether an extracted area on a metallic painted surface is caused by a scratch or by paint flakes, or from the area of the area.

JP 2014-66657 A

However, in Patent Document 1, it is assumed that the finer the scratches, the more difficult it becomes to distinguish them from paint flakes. In addition, an image of the painted surface is acquired by a camera, and a smoothing filter is applied to the acquired image, that is, a non-defective image is created by blurring, and only scratches are extracted by taking the difference between the non-defective image and the original image. It is based on image processing and is not applicable for visual inspection.

Accordingly, an object of the present invention is to provide a method for accurately observing a metallic coated surface by visual observation.

The coated surface observation method according to the present invention, which solves the above problems,
A light source that irradiates a metallic coating surface containing aluminum flakes or mica flakes glittering material in the coating film with linearly polarized light without a wavelength plate,
and polarized goggles worn by an observer,
As the polarizing goggles, the angle formed by the polarization direction of the irradiation light from the light source and the polarization direction of the polarizing goggles is 90 degrees,
The observer visually observes reflected light and scattered light from the aluminum flake or mica flake luster material through the polarizing goggles on the metallic coated surface without interposing a wave plate,
The polarized goggles prevent the reflected light and scattered light from the metallic coated surface containing the aluminum flake or mica flake luster material from being visually recognized in the polarization direction of the irradiated light ,
From the metallic painted surface containing the aluminum flakes or mica flakes glittering material containing scratches and foreign matter, the orthogonal polarization component accompanying the depolarization including the polarization component orthogonal to the polarization direction of the irradiation light is visually recognized,
Perform a visual inspection of the visual inspection including scratches and foreign substances on the metallic painted surface,
It is characterized by

According to the present invention, the metallic coated surface can be accurately observed visually.

Fig. 2 is a schematic perspective view of a first contrast; FIG. 11 is a schematic perspective view of a second contrast; 1 is a schematic perspective view of a first form of the invention; FIG. Figure 3 is a schematic perspective view of a second form of the invention; Fig. 3 is a schematic perspective view of a third embodiment of the invention;

The present invention will be further described below while showing embodiments of the present invention.

INDUSTRIAL APPLICABILITY The present invention is a coating surface observation method that enables accurate visual recognition of scratches, foreign matter, bumps, dents, irregularities, rain stains, etc. on a metallic coating surface. Visual recognition can be useful for detection of abnormalities and the like, as well as subsequent repair or restoration.

Prior to the embodiments of the present invention, the comparison will be explained in advance, and the positioning of the following embodiments of the present invention will be clarified.

<First contrast: Fig. 1>
As shown in FIG. 1, for example, when randomly polarized light (also referred to as non-polarized light or natural light) is irradiated from a light source 10A onto a metallic coated surface S, reflected light and diffused light that can be seen even on a solid coated surface are generated. In addition, reflected and scattered light is generated from the luster material in the coating film.
FIG. 1 shows a first aspect of comparison when a metallic coated surface irradiated with randomly polarized light is observed without polarizing goggles. For the sake of comparison with polarized goggles, which will be described later, the illustration is made assuming that there is a translucent lens 20A that does not have a polarizing function.

Regarding the actual painted surface S with the scratches, when dust is artificially attached to the vicinity away from the scratched area and the randomly polarized reflected light is visually observed 30 from the light source 10A, the painted surface S Reflected and diffused light is strong and feels dazzling.
It was also found that in the area to which dust was artificially adhered, it was indistinguishable from the bright-spotted reflected and scattered light exhibited by the luster material.
Furthermore, the scratches that actually exist cannot be visually recognized because they are buried in the reflection on the coated surface S, the diffused light, the bright-spotted reflection from the luster material, and the scattered light.

<Second Contrast: Figure 2>
FIG. 2 shows a second comparison, which is an example in which the coating surface S is irradiated with linearly polarized light in the X direction from the light source 10 and the linearly polarized light in the X direction is transmitted through the polarizing goggles 20 .
When the polarizing goggles 20 are installed so as to transmit the linearly polarized light in the X direction as well as the irradiation light (the polarization direction of the polarizing goggles 20 is represented by the line in the X direction), the reflected and scattered light from the coated surface S is strong and when you actually look at it, you feel glare.
In addition, the reflected and scattered light from the luster material in the coating film was strong, and the intentionally attached dust and scratches could not be visually recognized.

<First embodiment of the present invention: Fig. 3>
FIG. 3 shows an embodiment in which the coated surface S is irradiated with linearly polarized light in the X direction from the light source 10 and linearly polarized light in the Y direction is transmitted through the polarizing goggles 20 . Y direction lines are shown on the polarized goggles 20 .
When the coating surface S is irradiated with linearly polarized light in a certain direction, for example, the X direction, the polarization direction of the reflection on the coating surface S, the diffused light, the reflection from the luster material, and the scattered light is mainly in the same X direction as the irradiated light. be.

On the other hand, when a scratch, dust, etc., is irradiated with linearly polarized light in the X direction, the reflected and scattered light from the scratch, dust, etc. includes not only the polarized light component in the X direction, which is the same direction as the irradiated light, but also the polarized light component in the Y direction, which is orthogonal to the irradiated light. A directional polarization component is also included. This phenomenon is called depolarization.
Therefore, when the coated surface S having scratches, dust, etc., is irradiated with linearly polarized light in the X direction, the polarizing goggles 20 block the reflected light from the coated surface S, the diffused light, the reflected light from the luster material, and the scattered light. , Only the Y-direction polarized component generated by the depolarization action of dust, etc. is visible, and as a result, scratches, dust, etc. can be visually recognized with good contrast without being buried in the reflected and scattered light from the glitter material.

<Second form of the present invention: Fig. 4>
FIG. 4 shows an embodiment in which the light source 10 irradiates the coating surface S with linearly polarized light in a direction that forms an angle α with the Y direction on the XY plane, and the linearly polarized light in the Y direction is transmitted through the polarizing goggles 20 .
The angle α between the polarization direction of the irradiation light and the polarization direction of the polarizing goggles is continuously changed. In this case, for example, a holding frame for holding the polarizing filter 10a provided in front of the light source 10 is rotatable around the optical axis.

According to this embodiment, by continuously changing the angle α, scratches, dust, etc. appear and disappear, making them easier to see.
The angle α is 80°≦angle α≦100°, more preferably 85°≦angle α≦95°.

<Third embodiment of the present invention: Fig. 5>
FIG. 5 shows an embodiment in which the coated surface S is irradiated with linearly polarized light in the Y direction from the light source 10 and linearly polarized light parallel to the XZ plane is transmitted through the polarizing goggles 20 .
As shown in FIG. 5, the angle θ ₁ of the optical axis of the irradiation light with respect to the coating surface S is a shallow angle, for example, 0°<θ ₁ ≦10° (0° is also included because the coating surface is curved. ), and observed from the direction opposite to the irradiation direction from the angle θ ₂ formed by the normal line L of the coated surface from an angle of, for example, 0° < θ ₂ ≤ 45°, Scratches, dust, etc. can be visually recognized with better contrast.

As described above, the present invention includes the following aspects.
(First aspect)
A linearly polarized light source that irradiates the metallic painted surface,
and polarized goggles worn by an observer,
A painted surface observation method, wherein an observer observes the metallic painted surface at an angle of greater than 0 degrees between the polarization direction of the light emitted from the light source and the polarization direction of the goggles.

(Second aspect)
A coated surface observation method according to a first aspect, wherein observation is performed while continuously changing the polarization direction of the light emitted from the light source.

(Third aspect)
The coated surface observation method according to the first aspect, wherein an angle α between the polarization direction of the light emitted from the light source and the polarization direction of the goggles is 80°≦α≦100°.

(Fourth aspect)
Irradiation light is emitted from the light source at an angle of 0° ≤ θ ₁ ≤ 10° with respect to the metallic painted surface, and the normal line of the painted surface is irradiated from the direction opposite to the irradiation light _. A coated surface observation method according to a first aspect, wherein observation is made at an angle θ ₂ of 0°<θ ₂ ≦45°.

(Fifth aspect)
2. The method for observing a painted surface according to claim 1, wherein the angle formed by the polarization direction of the light emitted from the light source and the polarization direction of the goggles is 90 degrees.

The polarized goggles include those in the form of polarized lens spectacles, etc., in addition to the goggle type that surrounds the eyes.
The polarization direction of the polarized goggles is desirably the vertical direction on the short side of the horizontally long polarized goggles.
Moreover, it is desirable that the irradiation light has a polarization direction parallel to the coated surface (S-polarized light).

10... light source, 20... polarizing goggles, 30... observer, S... metallic coated surface.

Claims (2)

A light source that irradiates a metallic coating surface containing aluminum flakes or mica flakes glittering material in the coating film with linearly polarized light without a wavelength plate,
and polarized goggles worn by an observer,
As the polarizing goggles, the angle formed by the polarization direction of the irradiation light from the light source and the polarization direction of the polarizing goggles is 90 degrees,
The observer visually observes the reflected light and scattered light from the aluminum flake or mica flake luster material through the polarizing goggles on the metallic coated surface without interposing a wave plate,
The polarized goggles prevent the reflected light and scattered light from the metallic coated surface containing the aluminum flakes or mica flakes luster material from being visually recognized in the polarization direction of the irradiated light ,
From the metallic painted surface containing the aluminum flakes or mica flakes glittering material containing scratches and foreign matter, the orthogonal polarization component accompanying the depolarization including the polarization component orthogonal to the polarization direction of the irradiation light is visually recognized,
Perform a visual inspection of the visual inspection including scratches and foreign substances on the metallic painted surface,
A coated surface observation method characterized by: Irradiating light from the light source at an angle of 0° < θ ₁ ≤ 10° with respect to the metallic painted surface, and irradiating from the opposite direction to the irradiated light from the normal to the painted surface 2. The method for observing a coated surface according to claim 1, wherein the observation is made at an angle of 0<[theta] ₂ <45[deg.].

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