Prism Lights or Plates for Windows, Vaults and the like.
Year: 1897

page_text: Date of Application, 4th Dec., 1897-Accepted, 19th Feb., 1898
COMPLETE SPECIFICATION.
Prism Lights or Plates for Windows, Vaults and the like.
I, JOHN MEIGGS EWEN, of No. 1129, The Rookery, Chicago, County of Cook,
State of Illinois, United States of America, Mechanical Engineer, do hereby declare
the nature of my invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement;-
My invention relates to prism lights and has for its object to provide certain new
and useful improvements in the same of such a nature as to combine, as it were, the
lens idea and the prism idea. Hence I have called it a lenticular prism.
It is illustrated in the accompanying drawing, wherein;-
Figure 1 is a face view of a prism tile or light;
Figure 2 is a section through the same;
-
Figure 3 is a view of the back of the prism light show in Figure 1;
Figure 4 is a section through a prism light showing a modified construction;
Figure 5 is a view of the back of the prism light shown in Figure 4;
Figures 6, 7 and 8 show modified constructions;
Figure 9 is a perspective view of a prism plate having prisms on one side with
a series of lens like or arched surfaces on the opposite side;
Figure 10 is a cross section therethrough;
Figure 11 is a perspective of a similar light, the parts being modified in propor-
tion so that the parallel convex projections join at their edges.
Like letters refer to like parts throughout the several figures.
I have shown in the drawing a number of prism tiles, each having a series of
prisms extending across its face, the tile being provided with curved outer surfaces.
My invention is preferably used in connection with window lights, but it is evident
that it may be also used in connection with vault lights and the like. When a
room or an appartment to be lighted is provided with a small window, it is often
difficult to produce a proper and desirable distribution of the light. By the use of
my present invention, I am enabled to secure a wide distribution of light under such
circumstances.
As illustrated in Figure 1, I have shown a prism light A provided on one face
with the prisms B. The outer face of the prism light is provided with a curved
surface C. This surface may be either concave or convex and may be spherical in
form, as shown for example in Figure 3, or in the nature of the surface of a
cylinder, as shown for example in Figure 5. This surface may be of various
forms. For example, it may extend only over a part of the outer face of the tile,
as shown for example in Figure 6, or it may be both concave and convex, as shown
In Figure 7, or as shown in Figures 9 and 10, and the concave portions may be
emoved, as shown in Figure 11, or in other words there may be a series of convex
parts C arranged parallel with each other, their edges meeting each other. Instead
of having the outer face of the tile curved, I may curve the prism face, as shown
or example, in Figure 8. It is of course evident that many other constructions
nay be used and I have not attempted to set them forth in detail, but have only
llustrated my invention sufficiently to make its application clear, and therefore
I do not wish to be limited to the construction shown.

page_text: The ordinary prism lights having plain receiving faces and plain refracting
faces under ordinary cases work in a satisfactory manner, throwing the light into
a room, but all of it going above a certain direction from the prism plate. In
some of the prisms the light is very much concentrated, all of it going in a direction
which is bounded only by a few degrees, perhaps not more than eight or ten.
Where a general illumination is wanted in a room, it is desirable that this light
shall be distributed through a larger angle than this, and this may be accomplished
by any of the various modifications of my general invention herein shown. In the
first place, it is old to do it by putting in the same prism plate, prisms of different
angle. Another manner of accomplishing this is by either bending the prisms into
a curve in any direction or by bending the receiving surface in some manner.
treatment of the outer surface may take the form of perhaps a bull's-eye on one
light or it may take the form of corrugations, or it may take the form of convex
surfaces running across the prism light in a horizontal direction or in a diagonal
direction. It may also take the form of concave surfaces running across the prism
light in any direction.
This
Having now particularly described and ascertained the nature of the said inven-
tion, and in what manner the same is to be performed, I declare that what
I claim is:
1. As a new article of manufacture, a prism light made of a single piece of trans-
parent material relatively thin and provided on one side with a series of parallel
prisms systematically arranged to produce an increased illuminating effect and on
the other side with a series of similar convex projections, the convex surface of
each projection being bounded by an arc of a circle, the arc of each projection
joining or intersecting the arcs of the adjacent projections, and the convex pro-
jections being parallel with the prisms, substantially as set forth.
2. As a new article of manufacture, a prism light made of a single piece of trans-
parent material relatively thin and provided on one side with a series of parallel
prisms systematically arranged to produce an increased illuminating effect and on
the other side with a series of similar convex projections, the convex surface of each
projection being bounded by an arc of a circle, the arc of each projection joining
or intersecting the arcs of the adjacent projections and the convex projections being
parallel with the prisms and substantially the same width so as to be placed
opposite, substantially as set forth.
3. As a new article of manufacture, a prism light made of a single piece of trans-
parent material and provided on one side with a series of parallel prisms
systematically arranged to produce an increased illuminating effect and on the other
side with at least one convex projection parallel to the prisms, the convex surface
of such projection being bounded by an arc of a circle, whose centre is opposite the
prism side.
DL:
D1007