Article capable of creating a moire effect

An article, illustratively a lamp bulb envelope, for creating a moire effect has a plurality of transparent and nontransparent regions on its surface. When viewed from a point external to the envelope, the individual nontransparent regions on the surface of the envelope which is nearest to the point appear as superimposed upon and intersecting with nontransparent regions on the surface furtherest from the point. The apparent intersections produce a moire effect which is enhanced by varying the line of sight to the bulb. The family of moire curves appear as transversely running curves which pass through the points of apparent intersection of individual nontransparent regions along the near and far faces. The nontransparent regions may be either light diffusive (translucent) or light nontransmissive (opaque) in nature and may be created by abrading the surface of the envelope or by application of opaque or diffusive coatings onto the surface of the envelope. When an actual filament, arranged within the envelope, is energized to emit light, an apparent filament appears in inverted relationship with the actual filament within the envelope.

It is known that the moire effect occurs when a family of actual curves is 
superimposed upon a second family of actual curves to produce a third 
family of apparent curves. In the moire effect, each of the individual 
curves of the third family of apparent curves passes through points of 
intersection defined by the individual curves of the first and second 
families of curves. 
In the present invention, an incandescent electric lamp is provided which 
utilizes the moire effect to create a dynamic and decorative effect. A 
three-dimensional object, in the form of a lamp envelope in the preferred 
embodiment, is provided with a plurality of transparent regions which are 
each separated from the next adjacent transparent region by a 
nontransparent region. The nontransparent regions may be either 
translucent (light diffusive) or opaque (light nontransmissive) in nature. 
When viewed from a point external to the object, the non-transparent 
regions on the surface of the object which is furtherest from the external 
point are discernible through the transparent regions on the surface of 
the object which is nearest to the external point. The nontransparent 
regions along the near surface of the object appear as superimposed upon 
and intersecting with the non-transparent regions along the far surface of 
the object. The apparent superimposition and intersection of 
nontransparent regions on the near and far surfaces of the object produces 
the moire effect, i.e. the effect that a third family of apparent curves 
passes through points of intersection defined by nontransparent regions on 
the near and far surfaces of the object. Relative movement between the 
observer and the three-dimensional body results in variation in both the 
pattern and orientation of the third family of curves. 
The variation in the third family of curves creates a highly decorative 
effect when the pattern of transparent and nontransparent regions are 
applied to the envelope of an incandescent lamp. 
In such a lamp, the filament creates a highly pleasing visual effect. 
Further, an apparent filament appears in inverted relationship with the 
actual filament when the filament is energized to produce light. The 
effect of an apparent filament, which also occurs in other lamps having 
nondiffusive finishes provides an additional decorative effect here. 
It is an object of the present invention to provide a lamp envelope with a 
primary pattern of a plurality of non-transparent and transparent regions 
to create a decorative secondary effect. 
It is another object of the invention to provide a lamp envelope in which 
the moire pattern varies in response to relative movement between the 
observer and the envelope to create a highly pleasing visual effect.

In accordance with the present invention, a three-dimensional object 10 is 
provided. Illustratively, the object 10 comprises the hollow, generally 
spherical, envelope 11 of an incandescent lamp. As shown in FIG. 1, the 
spherical portion 11 terminates in a tubular portion 12 to which a 
conventional electrical base 13 is connected. 
As seen in FIGS. 1 and 2, a plurality of transparent regions 14 are 
provided in a predetermined pattern along the surface periphery of the 
lamp envelope 10 by laying down a plurality of nontransparent regions, 
such as lines 15. Each transparent region 14 is separated from the next 
adjacent transparent region by a nontransparent region 15. The 
nontransparent regions may be either light diffusive (translucent) or 
light nontransmissive (opaque). As shown, the surface of the envelope 10 
appears as alternating strips of transparent regions 14 and nontransparent 
regions 15. Each individual region 14, 15 takes the shape of a solid 
arcuate segment which terminates at a lower portion of envelope 10. 
However, the individual regions may take a variety of alternative forms 
arranged in alternative configurations on or within the envelope 10. For 
example, the individual regions may be formed from geometric shapes such 
as triangles or dots arranged in various patterns to create the moire 
effect and each of the regions may illustratively comprise endless 
circular or spiral segments encompassing portions of the envelope. 
As seen in FIG. 2, which is a top view of the envelope, the alternating 
strips of transparent and nontransparent regions 14 and 15 appear as bands 
16 of strips which extend radially from the pole 17 of the spherical 
envelope 10 and terminate at electrical base 13. It should be apparent, 
however, that the strips 14, 15 may be arranged in a variety of 
alternative orientations along the surface of the envelope 10. For 
example, the individual strips 14, 15 may comprise endless line segments 
such as circular loops, and each of the individual strips 14,15 may extend 
along one of a plurality of parallel spaced horizontal, vertical or angled 
planes of envelope 10. 
The nontransparent strips 15 can be created in a variety of ways. For 
example, portions of a generally transparent envelope 10 can be masked in 
conventional fashion. Abrasives, such as aluminum oxide, can then be used 
to abrade the unmasked portions of the envelope 10 so that they become 
nontransparent. A variety of conventional alternative methods may be 
utilized to produce the nontransparent portions. A variety of physical or 
chemical methods may be utilized to abrade or etch the surface of the 
workpiece or various diffused or opaque coatings may be applied to the 
workpiece surface to create the nontransparent regions. 
When viewed from a point such as A, which is external to the envelope 10, 
portions of the far surface of the envelope 10 will be discernible through 
the transparent regions of the near surface of the envelope 10. The 
alternating transparent and nontransparent regions, 14 and 15 
respectively, on each of the near and far surfaces takes the appearance of 
strips which extend along each of the near and far surfaces of the 
envelope. The nontransparent strips on the near surface of the object 
appear to intersect with the nontransparent strips on the far surface. 
Thus, when viewed from the external point A, one sees a first family of 
curves or strips along the near surface which are superimposed over and 
appear to intersect with a second family of curves along the far surface 
of the envelope 10. The apparent intersection of the first and second 
families of curves gives rise to a third family of apparent curves whose 
individual curves appear to pass through apparent points of intersection 
defined by individual curves of the first and second family of curves. 
The general moire effect is shown in two dimensional space in FIG. 5. In 
FIG. 5 (Excerpt from Dictionary of Scientific and Technical Terms, D. N. 
Lapedes, Ed-in-chief, McGraw-Hill, N.Y., N.Y. 1974) a first family of 
curves run generally parallel to curve 26 and a second family of curves 
run generally parallel with curve 27 and intersect with the first family 
of curves. The family of apparent moire curves extend generally transverse 
to the first and second family of curves and pass through points of 
intersection between individual curves of the first and second family of 
curves. The moire effect is enhanced when the first and second family of 
curves are arranged in three-dimensional space, as in the present 
invention. 
By changing the location of the external point A from which the envelope 10 
is viewed, the orientation and the pattern of the third family of curves 
will vary since movement of the external point A relative to the envelope 
10 varies the orientation between the external point A and portions of the 
near and far surfaces of envelope 10. This ability to vary the moire 
effect by relative movement of the external point A gives rise to a 
decorative effect when the envelope 10 comprises a conventional lamp bulb 
envelope. An observer viewing a lamp bulb in accordance with the present 
invention will observe a moire effect. By changing his or her line of 
sight to the envelope, for example, by simply moving one's head from side 
to side, the moire effect will vary dramatically. 
In addition, when an actual filament 30 is energized to emit light, an 
apparent filament 31 appears within the envelope 20 and in inverted 
relationship to the actual filament, providing a further decorative effect 
(see FIG. 3). An actual filament disposed within envelope 10 will also 
result in the appearance of an apparent inverted filament within envelope 
10. The use of a filament having low surface brightness increases the 
effect since the apparent filament such as 31 will be more readily 
observable. 
In FIG. 3, another embodiment of a lamp envelope is shown. Envelope 20 is 
generally pear-shaped. A plurality of transparent regions 22 and 
nontransparent regions 21 are provided along the periphery of the envelope 
20. The regions 21 and 22 are depicted as generally arcuate strips or 
curves. In the embodiment of FIGS. 3 and 4, the moire effect is 
discernible by viewing the envelope 20 from a point B external to the 
envelope. Through the transparent portions along the near face of the 
envelope, one observes a first family of curves superimposed over and 
intersecting with a second family of curves. One of these families of 
curves appears along the surface of the envelope 20 nearest to the 
external observation point and the other family of curves appears along 
the surface of the envelope 20 furthest from the external point B and is 
observed through the transparent portions on the near surface of envelope 
20. 
As shown in FIGS. 2 and 4, the strips 14, 15 and 21, 22 radiate from the 
vicinity of respective poles 17 and 25 located at the upper portion of the 
respective envelope. It should be apparent that the poles can be located 
anywhere on the surface of the envelope and that a plurality of poles can 
be utilized in place of the single pole depicted. In addition, it has been 
found that slight misalignment of the curves 14, 15 and 21, 22 from the 
respective poles 17 and 25 enhances the moire effect. Accordingly, the 
strips 14, 15 and 21, 22 are arranged in several bands so that the 
majority of individual strips are offset from the respective poles 17, 25. 
In the case of light diffusive nontransparent portions, light scattered by 
the diffusive portions must compete with direct filament light to achieve 
the moire effect. Accordingly, in a preferred embodiment, a bulb having a 
large filament area and sufficiently low surface brightness to enable one 
to discern light which is scattered from the light diffusion regions is 
utilized. Similarly, in the case of opaque, nontransparent portions, 
excessive filament brightness can diminish the moire effect. 
The transparent portions of the envelopes 10,20 may be either clear or 
colored. Coloring can provide an esthetically pleasing appearance. 
However, the coloring must not be so dark that the far face of the 
envelope surface cannot be discerned through the near face. 
The width of the respective nontransparent (diffuse or opaque) regions and 
of the transparent regions can be varied to optimize the moire effect. In 
addition, by varying the configuration and shape of the transparent and 
nontransparent regions on the near and far surfaces of the envelopes 10,20 
different moire patterns can be produced. 
It will be evident to those having ordinary skill in the art that the 
foregoing description is merely illustrative, that the present invention 
may take a variety of alternative forms and that the scope of protection 
afforded the present invention is to be determined from the appended 
claims.