![]() Up: Patent Index |
D27,492 · Jacobs · "Design for a Lens for Gratings" · Page 1 Home > Prism Glass > Patent Index > Page 1 |
![]() D27,492: 1 of 2 |
To all whom it may concern: Be it known that I, JACOB JACOBS, of Brooklyn, in the county of Kings, and in the State of New York, have invented a certain new and original Design for a Lens for Illuminating-Gratings; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, in which— Figure 1 is a perspective view of a lens embodying my design, and Fig. 2 a cross-section of the same. Letters of like name and kind refer to like parts in each of the figures. The object of my invention is to provide a design for lenses for illuminating-gratings; and to this end said invention consists in the design for a lens, substantially as hereinafter set forth. The leading feature of my design consists of adjacent parallel ribs or prisms on the lens, one of which is slender, or narrow in cross-section, compared with the other. |
The lens, as shown in the drawings, is in the form
of a rectangular plate A, with one face plane and two straight parallel
ribs or prisms B and C on its opposite face. Said ribs are triangular
in cross-section, and one, B, projects farther from the plate than the
other and has both of its sides inclined relative to the plate A and
slightly curved. The inclination of said sides is slight, so that the
rib is comparatively thin. The other rib, C, has its side adjacent to
the rib B curved convexly and its other side curved concavely. Having thus described my invention, what I claim is— The design for a lens, substantially as set forth. In testimony that I claim the foregoing I have hereunto set my hand this 7th day of May, 1897.
JAS. E. HUTCHINSON, CHAS. J. WILLIAMSON. |