Reflecting diffraction grating for minimizing anomalies

Claim 2

In a reflecting diffraction grating comprising a plurality of grooves for light diffraction, each of said grooves being formed by first and second reflecting surfaces, the improvement in that said second reflecting surface has a convex configuration for preventing light reflected from said first reflecting surface from interfering with light reflected from said second reflecting surface and for scattering thereat light reflected from said second reflecting surface, said convexly configured second reflecting surface having a surface roughness greater than said first reflecting surface thereby to reduce anomalies.

Claim 3

The improved reflecting diffraction grating according to claim 1, wherein the convex configuration of said second reflecting surface is formed by an evaporable material which is evaporated onto said second reflecting surface.

Claim 4

The improved reflecting diffraction grating according to claim 2, wherein said evaporable material has a thickness lying in the range from 1/20 to 1/5 of the grating constant.

Claim 5

The improved reflecting diffraction grating according to claim 2, wherein said evaporable material has a thickness of one-tenth of the grating constant.

Claim 6

The improved reflecting diffraction grating according to claim 2, wherein said evaporable material comprises at least one material selected from the group consisting of aluminum, chromium, magnesium fluoride, silicon and germanium.

Claim 7

The improved reflecting diffraction grating according to claim 3, wherein said evaporable material comprises at least one material selected from the group consisting of aluminum, chromium, magnesium fluoride, silicon and germanium.

Claim 8

The improved reflecting diffraction grating according to claim 4, wherein said evaporable material comprises at least one material selected from the group consisting of aluminum, chromium, magnesium fluoride, silicon and germanium.

Claim 9

In a reflecting diffraction grating comprising a plurality of grooves for light diffraction, each of said grooves being formed by first and second aluminum layers defining first and second reflecting surfaces, respectively, the improvement in that only a surface of said second aluminum layer has thereon a convex configuration formed by at least one evaporable material selected from the group consisting of aluminum, chromium, magnesium fluoride, silicon and germanium, said convex configuration preventing light reflected from the surface of said first aluminum layer from interfering with light reflected from the surface of said second aluminum layer and scattering thereat light reflected from the surface of said second aluminum layer, said convexly configured second reflecting surface having a surface roughness greater than said first reflecting surface thereby to reduce anomalies.

Claim 10

In a reflecting diffraction grating comprising a plurality of grooves for light diffraction, each of said grooves being formed by first and second aluminum layers defining first and second reflecting surfaces, respectively, the improvement in that only a surface of said second aluminum layer has thereon a convex configuration formed by at least one evaporable material selected from the group consisting of aluminum, chromium, magnesium fluoride, silicon and germanium, said convex configuration preventing light reflected from the surface of said first aluminum layer from interfering with light reflected from the surface of said second aluminum layer and scattering thereat light reflected from the surface of said second aluminum layer, said convexly configured second reflecting surface having a surface roughness greater than said first reflecting surface thereby to reduce anomalies.

Claim 11

The improved diffraction grating according to claim 8, wherein said evaporable material has a thickness lying in the range from 1/20 to 1/5 of the grating constant.

Claim 12

In a reflecting diffraction grating comprising a light reflecting supporting medium having a plurality of light reflecting grooves ruled in a surface thereof, the improvement wherein each groove consists of a first planar reflecting surface having first and second edges; a second planar reflecting surface one edge of which intersects the first edge of said first planar reflecting surface and the other edge of which intersects the second edge of the first planar surface of an adjacent groove, and a convex-shaped reflecting projection having a surface roughness greater than said first reflecting surface and extending from said second planar reflecting surface and having a first edge contiguous with said other edge of said second planar surface and a second edge intersecting said second planar surface at a location spaced apart from the intersection of said second reflecting surface with said first reflecting surface by the exposed planar portion of said second reflecting surface therebetween.

Claim 13

In a reflecting diffraction grating comprising a light reflecting supporting medium having a plurality of light reflecting grooves ruled in a surface thereof, the improvement wherein each groove consists of a first planar reflecting surface having first and second edges; a second planar reflecting surface one edge of which intersects the first edge of said first planar reflecting surface and the other edge of which intersects the second edge of the first planar surface of an adjacent groove, and a convex-shaped reflecting projection having a surface roughness greater than said first reflecting surface and extending from said second planar reflecting surface and having a first edge contiguous with said other edge of said second planar surface and a second edge intersecting said second planar surface at a location spaced apart from the intersection of said second reflecting surface with said first reflecting surface by the exposed planar portion of said second reflecting surface therebetween.

Claim 14

The improved reflection diffraction grating according to claim 10, wherein the thickness of said convex-shaped projection lies in a range of 1/20 to 1/5 of the grating constant.

Claim 15

The improved reflection diffraction grating according to claim 11, wherein the thickness of said convex-shaped projection is 1/10 of the grating constant.

Claim 16

The improved reflection diffraction grating according to claim 10, wherein the material of which said convex-shaped projection is made is a material selected from the group consisting of aluminum, chromium, magnesium fluorid, silicon and germanium.

Claim 17

The improved reflection diffraction grating according to claim 10, wherein the distance between the first and second edges of said convex-shaped projection along the surface of said second planar reflecting surface is greater than distance along said second planar reflecting surface between the one edge of said second planar reflecting surface and the intersection of said second planar reflecting surface with the second edge of said convex-shaped projection.

Claim 18

The improved reflection diffraction grating according to claim 14, wherein the distance between the edges of said first planar reflecting surface is greater than the distance between the edges of said second planar reflecting surface.