Methods and devices for determining the contact angle of a drop of liquid placed on a substrate
AssigneePhotonetics
InventorsPhilippe Martin, Gilles Le Boudec
Life of this patent
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Abstract
The invention relates to improvements to methods and devices for determining the contact angle of a drop of liquid placed on a substrate. The device comprises: a support 12 for a substrate 11 which receives a drop of liquid 9; a light source 1; optical means, formed for example by a plate with parallel faces 21 rotatable about its axis 22 and whose inclination with respect to the axis may be modified, with a reflecting prism 5a, for forming a primary beam 6a, advantageously annular, striking the interface 8 between drop and substrate; a receiving surface 13a, 13b formed by a reflection diffusing surface; a reflecting surface 17; and a camera C.
Claims7
Method for determining the contact angle of a drop of liquid placed on a substrate, for any contact angle less that 45.degree., which comprises the steps of:
- directing perpendicularly to the substrate a primary beam of parallel light for illuminating a zone which contains an interface between the periphery of the drop and the substrate,
- determining the illumination transition zone presented onto at least one receiving surface by a secondary beam resulting from the interaction of the primary beam with the drop and the substrate, said receiving surface being a reflection diffusing surface, intercepting said secondary beam thereby forming a diffusing receiving surface emitting light rays,
- reflecting the light rays from said diffusing receiving surface through a reflecting surface disposed facing said diffusing receiving surface, and collecting the rays, reflected by said reflecting surface, by a camera.
Device for determining the contact angle of a drop of liquid placed on a substrate, for any contact angle less than 45.degree., in which a primary beam of parallel light is directed perpendicularly to the substrate for illuminating a zone which contains the interface between the periphery of the drop and the substrate, said device comprising:
- at least one receiving surface, formed by a reflection diffusing surface, intercepting a secondary beam resulting from the interaction of said primary beam with the drop and the substrate, said at least one receiving surface forming a diffusing receiving surface emitting light rays, so as to determine the illumination transition zone presented onto said at least one receiving surface by said secondary beam,
- a reflecting surface disposed facing said diffusing receiving surface so as to reflect said light rays, and
- a camera for collecting said light rays reflected by said reflecting surface.
Dependencies are inferred from the claim text.