Method and apparatus for sensing reflected light and diffused light from a surface to indicate the roughness of said surface

Claim 1

A device for measuring the roughness of a surface which comprises: a source of light, an optical system which receives light from said source of light and directs said light at said surface at a predetermined angle of incidence, a first light-sensitive element disposed to receive light reflected from said surface at an angle of reflection substantially equal to said angle of incidence, a second light-sensitive element that is angularly spaced from said angle of reflection and that is disposed to receive light diffused and diffracted by said surface, and a circuit that senses the signals from said light-sensitive elements to compare said signals and to indicate a comparison of the signals as a measure of the roughness of said surface, a rotatable support positioned adjacent said surface, said source of light, said optical system, said first lightsensitive element, and said second light-sensitive element all being positioned in the same plane, and being fixedly mounted on and rotatable with said rotatable support, said rotatable support being rotatable about an axis which is normal to said surface to enable said first light-sensitive element and said second light-sensitive element to rotate about said axis, whereby said first light-sensitive element and said second light-sensitive element can be rotated as a unit relative to said surface about said axis.

Claim 2

A device for measuring the roughness of a surface which comprises: a source of light, an optical system which receives light from said source of light and directs said light at said surface at a predetermined angle of incidence, a first light-sensitive element disposed to receive light reflected from said surface at an angle of reflection substantially equal to said angle of incidence, a second light-sensitive element that is angularly spaced from said angle of reflection and that is disposed to receive light diffused and diffracted by said surface, and a circuit that senses the signals from said light-sensitive elements to compare said signals and to indicate a comparison of the signals as a measure of the roughness of said surface, a rotatable support positioned adjacent said surface, said source of light, said optical system, said first lightsensitive element, and said second light-sensitive element all being positioned in the same plane, and being fixedly mounted on and rotatable with said rotatable support, said rotatable support being rotatable about an axis which is normal to said surface to enable said first light-sensitive element and said second light-sensitive element to rotate about said axis, whereby said first light-sensitive element and said second light-sensitive element can be rotated as a unit relative to said surface about said axis.

Claim 3

A device for measuring the roughness of a surface which comprises: a source of light, an optical system which receives light from said source of light and directs said light at said surface at a predetermined angle of incidence, a first light-sensitive element disposed to receive light reflected from said surface at an angle of reflection substantially equal to said angle of incidence, a second light-sensitive element that is spaced from said angle of reflection and that is disposed to receive light diffused or diffracted by said surface, and a third light-sensitive element that is spaced from said angle of reflection and that also is spaced from said second light-sensitive element, a circuit that senses the signals from said light-sensitive elements to compare said signals and to indicate a comparison of the signals as a measure of the roughness of said surface, said circuit selectively sensing the signals from the said first light-sensitive element and said third light-sensitive element and from the said first light-sensitive element and said second light-sensitive element, said second light-sensitive element being spaced from the first said light-sensitive element an angular distance less than 5*, said third light-sensitive element being spaced from the first said light-sensitive element an angular distance greater than 5*.

Claim 4

A device for measuring the roughness of a surface which comprises: a source of light, an optical system which receives light from said source of light and directs said light at said surface at a predetermined angle of incidence, a first light-sensitive element disposed to receive light reflected from said surface at an angle of reflection substantially equal to said angle of incidence, a second light-sensitive element that is spaced from said angle of reflection and that is disposed to receive light diffused or diffracted by said surface, and a third light-sensitive element that is spaced from said angle of reflection and that also is spaced from said second light-sensitive element, a circuit that senses the signals from said light-sensitive elements to compare said signals and to indicate a comparison of the signals as a measure of the roughness of said surface, said circuit selectively sensing the signals from the said first light-sensitive element and said third light-sensitive element and from the said first light-sensitive element and said second light-sensitive element, said second light-sensitive element being spaced from the first said light-sensitive element an angular distance less than 5*, said third light-sensitive element being spaced from the first said light-sensitive element an angular distance greater than 5*.

Claim 5

The method of sensing the roughness of a surface which comprises: a. directing a beam of light toward an area of said surface at a predetermined incidence angle, b. sensing the amount of light which is reflected from said area of said surface at an angle of reflection that is substantially equal to said incidence angle and thereby sensing the amount of said area of said surface that is smooth, c. sensing the amount of light which is reflected, diffused and diffracted from said area of said surface at a first angle that is angularly spaced less than 5* from said angle of reflection and thereby sensing the amount of said area of said surface which has peaks of a first predetermined height, d. comparing the amount of light sensed at said angle of reflection with the amount of light sensed at said first angle to obtain an indication of the roughness of said area of said surface, e. sensing the amount of light which is reflected, diffused and diffracted from said area of said surface at a second angle that is angularly spaced greater than 5* from said angle of reflection and thereby sensing the amount of said area of said surface which has peaks of a second predetermined height, and f. comparing the amount of light sensed at said second angle with the amount of light sensed at said angle of reflection to obtain a further indication of the roughness of said area of said surface.

Claim 6

The method of sensing the roughness of a surface which comprises: a. directing a beam of light toward an area of said surface at a predetermined incidence angle, b. sensing the amount of light which is reflected from said area of said surface at an angle of reflection that is substantially equal to said incidence angle and thereby sensing the amount of said area of said surface that is smooth, c. sensing the amount of light which is reflected, diffused and diffracted from said area of said surface at a first angle that is angularly spaced less than 5* from said angle of reflection and thereby sensing the amount of said area of said surface which has peaks of a first predetermined height, d. comparing the amount of light sensed at said angle of reflection with the amount of light sensed at said first angle to obtain an indication of the roughness of said area of said surface, e. sensing the amount of light which is reflected, diffused and diffracted from said area of said surface at a second angle that is angularly spaced greater than 5* from said angle of reflection and thereby sensing the amount of said area of said surface which has peaks of a second predetermined height, and f. comparing the amount of light sensed at said second angle with the amount of light sensed at said angle of reflection to obtain a further indication of the roughness of said area of said surface.