HK1066045B - Illumination device for simulation of neon lighting - Google Patents

Description

Lighting device for simulating neon lighting

Technical Field

This application claims priority to provisional application No. 60/265,522, entitled "simulated neon lighting fixture for object illumination", filed on 31/1/2001.

The present invention relates to illumination devices using optical waveguides, and more particularly to illumination devices that simulate neon lighting using optical waveguides and high intensity low pressure light sources and are ideally suited for signage and advertising use.

Background

Neon lighting, which is produced by the electrical excitation of electrons in glass tubes filled with low-pressure neon, has for many years been the dominant position in the advertising industry and is used to outline open letters (channel letters) and building structures. Neon lighting is characterized by a uniform illumination of the light within the tube surrounding the gas over its entire length, independent of viewing angle. This characteristic makes neon lighting suitable for many advertising applications including written text and designs, as the glass tube can be made into curved and twisted structures that simulate written text and complex designs. Uniform lighting of neon lighting, typically without hot spot areas, can be used for advertising without visible and unsightly interference. Thus, any lighting device developed to replicate the effects of neon lighting must also have an axially uniform light distribution over its length and substantially uniformly around its circumference. It is also important that such lighting devices must have a brightness that is at least comparable to neon lighting. Moreover, since neon lighting is a mature industry, a competitive lighting fixture must be lightweight and have superior operability for penetration into the neon lighting market. It is well known that neon lighting devices are fragile in nature. Neon lighting devices are expensive to package and transport due to their fragility and heavy weight, primarily from their underlying support structure. Moreover, it is extremely difficult to start with, install, and/or replace neon lighting structures. Any lighting device that provides the advantages of neon lighting enumerated above while minimizing the disadvantages of size, weight, and operability would represent a significant advance in lighting technology.

U.S. patent No.4,891,896 issued to Boren on 9.1990 and assigned to Gulf Development corporation is one example of many attempts to reproduce neon lighting. Similar to such attempts, most prior art neon light simulations have yielded structures that are difficult to manufacture with little progress in weight and operability improvements. The Boren patent illustrates this by providing a plastic panel with the necessary low relief text. The material constituting the text is transparent and is coated with a translucent material. The surrounding material is opaque. When the panel is backlit, the text will emit light having an intensity similar to neon.

More recently, the introduction of lighter weight breakage resistant point light sources, exemplified by high intensity light emitting diodes, has made great hope for lighting devices that are interested in and that are making much effort in the direction of simulated neon lighting. However, these two characteristics of neon lighting, uniformity and brightness, have proven to be difficult obstacles to overcome, as the trade-off between improving the uniformity and brightness of the light distribution has largely hindered attempts to simulate neon lighting. For example, U.S. patent No.4,976,057 issued to Bianchi on 11.12.1990 describes a device comprising a transparent or translucent hollow plastic tube mounted adjacent to a sheet of material having an optically transparent region extending with the plastic tube. The panel is backlit by a light source, such as a light emitting diode. The light emitting diode is formed in the shape of a plastic tube. The plastic tube may be made in any shape including text. Although plastic tubes may be illuminated by such an arrangement, the light transmission efficiency of this arrangement is likely to cause the "glow" tube to have an intensity that is insufficient to be commensurate with neon lighting. The use of point sources such as light emitting diodes may provide intense light that rivals or exceeds neon lighting, but lack the required uniformity when arranged in an array and unfortunately provide alternating high and low intensity areas on the illuminated surface. Attempts to smooth the luminescence have resulted in unacceptably low intensity illumination.

It is therefore a principal object of the present invention to provide an alternative to neon lighting devices that is energy efficient and unbreakable.

It is another important object of the present invention to provide a lighting device that can be safely transported and economically operated while providing the practical efficacy of all neon lighting, including uniformity and brightness.

It is another object of the present invention to provide an alternative device for neon lighting that is environmentally friendly, does not require neon, and consumes significantly less electrical power than its corresponding neon lighting device.

Another important object is to provide an equivalent to a neon lamp which is easy to install without the need for complex high voltage electrical installations.

It is a further object to provide a lighting device that can be placed in a harsh environment such as a refrigerator without the need for a guard against accidental contact by the user.

These and other objects of the present invention will be apparent from and will be emphasized by a reading of the following discussion and the accompanying drawings.

Disclosure of Invention

The present invention uses a profiled rod of a material having waveguide properties that preferentially scatter light entering one side surface ("light receiving surface") such that the resultant light intensity pattern emitted by the other side surface ("light emitting surface") of the rod is elongated along the length of the rod. The light source extends along and adjacent the light receiving surface and is spaced from the light emitting surface a distance sufficient to produce an elongated light intensity pattern having a major axis along the length of the rod and a minor axis having a width that covers substantially the entire circumferential width of the light emitting surface. In a preferred arrangement, the light sources are an array of point light sources spaced apart a distance sufficient to allow a mapping of the light emitted by each point light source into the rod to produce an elongate and overlapping light intensity pattern along and circumferentially around the light emission surface such that the resultant light intensity pattern feels uniform across the light emission surface when viewed from the generally front and side.

Drawings

FIG. 1 is a front perspective view of the lighting device of the present invention;

FIG. 2 is a perspective view similar to FIG. 1 with a broken away portion to show the interior thereof;

FIG. 3 is an enlarged side view of the lighting device shown in FIG. 1;

FIG. 3A is an enlarged wall portion of the lighting device shown in FIG. 3;

FIG. 3B is an enlarged wall section similar to that shown in FIG. 3A with a variation of the structure;

fig. 4, 5 and 6 are front, side and top views, respectively, of a diode connected to a circuit board for use in the present invention, and fig. 5 also shows the structure of the light emitting diode and the circuit board in the device;

fig. 5A and 5B show side views of alternative configurations of diodes and circuit boards provided in the present invention.

Fig. 7A and 7B respectively show graphs illustrating light distribution characteristics of a single point light source and a schematic diagram of an apparatus for measuring the light distribution characteristics;

FIGS. 7C and 7D respectively show graphs illustrating the light distribution characteristics of a single point light source mounted in an apparatus constructed in accordance with the present invention and a schematic view of an apparatus for measuring the light distribution characteristics;

FIGS. 7E and 7F show a MacAdtt (Mercator) top projection of a waveguide with overlapping individual light distribution patterns and a side schematic view of the illuminated lateral surface, respectively;

FIG. 8 is a normalized graph of light distribution using elliptical light emitting diodes to assist in producing an elongated light intensity pattern;

FIGS. 9A, 9B and 9C illustrate several different internal positions of the light emitting diodes in the lamp envelope of the lighting device according to the present invention;

fig. 10A and 10B show examples of different lamp housing structures according to the present invention;

FIG. 11 shows a lighting device of the present invention having multiple rows of LEDs;

FIG. 12 illustrates one support technique for a lighting device made in accordance with the present invention;

FIG. 13 illustrates one connection technique for individual light emitting devices made in accordance with the present invention;

fig. 14 shows a variation in a preferred embodiment in which the diodes are tilted in the envelope;

fig. 15 shows another variation in which the diode is inverted in the lamp envelope;

FIG. 16 shows an embodiment in which the light emitting diode is located in a slot formed in the waveguide itself;

FIG. 17 shows another embodiment in which the light source is a light source that is itself elongate and extends in a direction parallel to the axis of the waveguide; and

fig. 18 shows a schematic diagram of electronic circuitry with light emitting diodes for providing an illumination sequence that may be used with the illumination device of the present invention.

Detailed Description

In order to provide the desired result, that is, as an effective illumination device for neon lighting simulation, it is important to select appropriate materials for the component parts and those parts appropriately and geometrically arranged so that the resulting illumination device has a substantially uniform light intensity distribution pattern over the entire surface and has the maximum brightness obtainable. For this purpose, it is necessary to use a high-intensity, small-size light source, and an element that acts both as an optical waveguide and as a light scattering element, but allows light to exit its surface from the side (a "leaky waveguide"). By placing the light source adjacent to the leaky waveguide in a particular manner so that the waveguide emits light uniformly at its side surfaces and maximizes the amount of light exiting the surface, applicants have been able to obtain an illumination device that rivals or is superior to the uniform emission of neon tubes. There are many types of light sources that have the requisite light intensity output required, but most of them are too large, fragile, or consume too much power for use. It is further recognized that the best light source may be one having a small diameter that provides uniform light output over its entire length. However, such light sources have not yet been developed to provide the required intensity. The applicant therefore believes that the most useful light source for this purpose is a string or strings of adjacently mounted substantial point light sources, such as spaced apart high intensity light emitting diodes.

The ultimate goal of the illumination device of the present invention is to simulate an illuminated neon tube that emits light of suitable intensity and uniformity throughout its length. The applicants therefore believe that it is important that the leaky waveguide (used to simulate a neon tube) be constructed of a profiled rod of a material having sufficient diffusivity to, together with the other elements of the invention, intuitively eliminate any discernable individual light distribution patterns produced by the individual light emitting diodes or other light sources. As described above, the profiled waveguide preferentially scatters light along its length but ultimately allows light to exit through its side surfaces. Such a waveguide provides each led with a visible elongated or elliptical pattern of light rays that is brightest at its center and weakens from its center continuously along the major and minor axes of the pattern. By spacing the light emitting diodes a distance apart and locating each light emitting diode a suitable distance from the exposed and laterally distal side of the leaky waveguide, the pattern of intensity distributions on the distal surface of the leaky waveguide is superimposed to such an extent that the variation of the pattern is flattened. This results in a resultant light pattern on the side surfaces that has uniform intensity along the length of the waveguide to an observer. Other elements of the lighting device of the present invention, including, for example, the shape of the light source, can help to construct the desired brightness and uniformity.

Structurally, a preferred embodiment of the present invention is depicted in fig. 1 through 6 and is designated generally by the reference numeral 10. The device 10 can be considered to have two main elements. The first element is a waveguide 12 having an exposed curved side surface 13 as a light emitting surface and a hidden side surface 15 as a light receiving surface (see fig. 3). Waveguide 12 is the previously mentioned leaky waveguide and surface 13 serves as the counterpart to the neon tube. In other words, light from the light source adjacent the surface 15 entering the waveguide from the side is preferentially scattered so that it leaves the surface 13 in a wide elongated light intensity distribution pattern. Intuitively, the waveguide 12 has a milky appearance when not illuminated from its interior due to the uniform scattering of ambient light entering the waveguide and eventually exiting its side surfaces. The applicant has found that acrylic materials suitably treated are suitable for scattering light and have a high impact resistance, and are preferred materials for constructing the waveguide elements of the present invention. When formed into a profiled rod, the rod has the desired leaky waveguide characteristics. Moreover, such materials are easily molded or extruded into rods having the desired shape for any desired lighting application, are very light in weight, and are capable of withstanding rough shipping and rough handling. Acrylic materials having desirable properties are readily available, such as from AtoHass corporation of philadelphia, pa under the subscription number DR66080, and have additional matte properties. When formed into a rod, the acrylic material can be observed to have desirable leaky waveguide characteristics. Other materials such as particulate molded (beaded) acrylic or polycarbonate, or spray coated acrylic or polycarbonate with the desired preferential light scattering properties may also be used for other applications.

The second element of the present invention is a lamp envelope 14 disposed adjacent to a surface 15 of the waveguide 12. The lamp envelope 14 includes a pair of adjoining sidewalls 20, 22 which abut the surface 14 and extend downwardly from the surface 14 and form an open-ended slot 18 extending generally along the length of the waveguide 12. The lamp housing 14 is typically used to house light sources and electrical accessories and to collect light that does not directly strike the surface 15 and redirect it to the waveguide. In other words, the envelope further serves to increase the collection efficiency of light by reflecting light incident on the inner surface of the envelope toward the waveguide 12 and aiding in the scattering of the light. From the perspective of an observer, it is desirable that the visual effect of the envelope 14 is not overly prominent with respect to the light emitting surface 13 of the waveguide 12; therefore, it is preferred that the outer surface of the lamp envelope be light absorbing so that the viewer appears dark. Further, it is preferred that the lamp housing is made of an impact resistant acrylic material, the outer walls 20 and 22 with the outer regions are formed of a dark colored acrylic and are therefore light absorbing, and the inner regions are formed of a white colored acrylic and are therefore light reflecting. These two regions are clearly seen in fig. 3A, which shows an enlarged section of wall 20 in which outer region 20a is dark acrylic and inner region 20b is white acrylic. This acrylic material is preferably the same material as used for the waveguide. Although the waveguide 12 and lamp housing 14 may be separately formed and suitably joined, it is preferred that the components be molded or extruded as one component with the formed slot 18 along a portion of the length.

Fig. 3B shows an alternative wall structure in which the wall 20' has three elements, an outer dark region 20c, an intermediate light reflecting region 20d, and a transparent wall 20e, which may be composed of a scattering acrylic as the waveguide. The outer and intermediate regions 20c and 20d may be dark and white coatings applied to the wall 20', which itself may be composed of a clear acrylic material or a scattering acrylic. The light reflective coating may be a color that matches the color of the light emitting diode, if desired.

While the above discussion sets forth a preferred construction for the lamp envelope, it should be understood that in some applications, the reflective and absorptive properties may be provided by light reflective and light absorptive coatings or bands. Furthermore, where visibility of the lamp envelope is less relevant, it may not be necessary to provide light reflecting and/or light absorbing properties to the outer surface of the sidewall.

One of the most beneficial features of the present invention is that the lighting device 10 can be easily bent to form a structure or text. The slots 18 allow the device 10 to be easily deformed and bent into a desired shape. Once the device 10 is molded, the light emitting diodes 24 and electrical connection board 26 are inserted into the slots 18, and the slots 18 are then filled with a filling compound. Thereafter, the filler or potting compound hardens, thereby maintaining the position of the light emitting diodes and the circuit board 26. There are various configurations of light emitting diodes 24 and plates 26 that may be located within the slot 18. Fig. 5A and 5B show examples of these structures. A preferred configuration is shown in figure 5, in accordance with the compact nature of this arrangement. However, with this arrangement, it is important to observe the orientation of the circuit board 26 in the slot 18 so that the board 26 extends along the length of the slot to facilitate bending. The flexibility of the circuit board 26 with attached leds 24 allows the rod-like structure to be inserted into the slot 18 with the apex of the leds 24 substantially abutting the lower surface of the waveguide 12 (as shown in fig. 3). It is also important that the potting compound 30 used to fill the grooves 18 have the desired light transmission characteristics and effectively maintain the position of the light emitting diodes and circuit board. The potting compound also serves to eliminate air gaps between the light emitting diodes and the waveguide. Preferably, the potting compound hardens into an impact resistant material having an index of refraction substantially matching the lamp envelope 24a of the light emitting diode 24 to minimize Fresnel (Fresnel) losses at the interface therebetween. The potting compound further increases structural strength by filling the grooves 18 and helps reduce the formation of hot spots on the side surfaces 13. These potting compounds may be selected from the generally available transparent variety, such as the material available from Loctite corporation of Rocky Hill, connecticut under the trade name durabond e00 CL. As also seen in fig. 3, the bottom surface of the device 10 may be covered by a light reflective surface 32, which may be, for example, a white potting compound or coating, and optionally covered with a light absorbing material 34. In those instances where the selected light emitting diodes 24 have a certain color, the light reflecting surfaces may also be selected to have a matching or substantially the same color. To take advantage of ambient light, certain dyes may be added to the acrylic material to cause the device 10 to exhibit some color that is readily discernable when viewed.

The intensity of the point light sources preferably used in the present invention is generally sufficient to provide the necessary brightness. The essence of the invention is, however, worth mentioning that it consists in a careful spreading or distribution of the individual light patterns of the point light sources, so that the light patterns preferentially spread along the light emission surface and form an elliptical or elliptical-like light intensity pattern. It is also important that the minor axis of the elliptical light intensity pattern extends substantially the entire circumferential width of the curved light emitting surface. The preferential spreading of each light intensity pattern along the waveguide also allows the light ray patterns to overlap. This in turn enables the present invention to provide a composite light pattern that appears uniform along and covering the entire light emitting surface.

There are various parameters that have an effect on the brightness and uniformity of the light intensity pattern emitted by the surface 13 of the waveguide 12. Of most importance are the scattering properties of the waveguide material, such as the gap "l" between the leds 24 shown in fig. 2, the lensing effect of the led lamp envelope and the internal optics in which the light emitting portion of the leds is located, the shape and configuration of the lamp envelope, and the distance "d" from the apex of the leds 24a to the apex 12a on the side surface 13 (shown in fig. 3). To improve the uniformity of the light intensity distribution pattern over the surface of the waveguide, the leds 24 must be positioned a predetermined distance "d" from the apex 12a of the waveguide. Placing the led too close to the surface will cause "hot spots" to occur, i.e. a region of higher light intensity locally appears at the surface 12a of the waveguide and deteriorates the quality of uniform light emission. Moving it too far from the surface 12a will significantly and undesirably reduce the total light intensity emitted by the waveguide 12 and may also prevent the minor axis of the ellipse or ellipse-like from extending over the circumferential width of the light emitting surface. By way of example only, it is believed that when the curved surface has a radius of curvature of about 3/16 inches (about 4.76mm), the device 10 (shown in FIG. 3) has a height "h" of about 31mm and a width "w" of about 9.5mm, while the light emitting diodes have a candle power of about 280mcd and are spaced about 12mm apart, the distance "d" should be about 17.75mm to 17.80 mm. It should be understood, however, that while a preferred waveguide structure similar in size to a neon tube is described above, other and different waveguide shapes may be used which also provide the desired uniform illumination.

For a better understanding of the working principle of the present invention, reference is now made to fig. 7A to 7F, which illustrate, as an example, examples of the variation of the light intensity and light pattern propagation of a typical diode compared to that of a lighting device constructed according to the present invention. A single light emitting diode or point light source provides a narrow intensity profile 54 as graphically illustrated in fig. 7A. Such a pattern can be produced by using a photocell type device 50 as shown in figure 7B and measuring the intensity of the light progressively from different angles to the centre line 51. Such a light pattern 54 should be the opposite of that shown in fig. 7C, where pattern 56 is quite wide, with a concomitant reduction in intensity along centerline 51. Figure 7C shows a wider pattern emitted by the side 13 of a waveguide 12 constructed in accordance with the present invention. As mentioned above, it is important that the distance "d" and the distance "l" by which the leds are spaced apart are such that the elliptical intensity patterns of the leds overlap as depicted in the schematic diagram of fig. 7E, while the projection depicted in fig. 7C schematically represents a plurality of leds providing a widened overlapping elliptical intensity pattern 31 on the side 13 of the waveguide 12. Fig. 7E is a top view of the light ray pattern area 24 on the side surface 13 using a mcatto (Mercator) type projection. The secondary axis of the light intensity pattern 31 is indicated by dashed line 33. As mentioned above, for any given size of waveguide and spacing of the point sources, it is important that the distance "d" is set appropriately so that the minor axis of the light intensity distribution pattern extends substantially the entire circumferential width along the curved side light emitting surface 13. For the purposes of this disclosure, a light intensity distribution pattern may be defined as the visible area of a light ray pattern extending from the central portion of the area that is visibly apparent to an observer.

To further aid in preferential diffusion and scattering of the light intensity pattern, applicants have further determined that the use of an elliptical shaped light emitting diode as shown in FIG. 6 is helpful. The best results are obtained when the elliptical light emitting diode is arranged with the major axis of the elliptical light pattern, as seen in top view, along the longitudinal axis of the waveguide 12. The characteristic light pattern of the oval light emitting diode is shown in fig. 8, which graphically depicts normalized light intensity along the major and minor axes. As can be seen, an oval shaped LED tends to direct light along its major axis as shown by curve 36.

The light weight and strength of the lighting device 10 of the present invention makes it suitable for mounting to virtually any surface through a variety of mounting techniques. For example, as shown in fig. 12, an extended length of the device 10 is mounted to a wall panel 44 in the form of a curtain rod using bracket hooks 40 and fasteners 42. Moreover, successive lengths of the device 10 can be readily juxtaposed, for example, as shown in FIG. 13, wherein dowels 46, matched to the refractive index of the material of the waveguides 12, 12', are inserted into complementary holes at each end. Other fastening techniques may be used including bonding the various lengths at their ends. In some instances, when the length is properly supported, the ends of the length may simply be placed in side-by-side contact. In this way, it can be easily understood that the lighting device 10 having an indefinite length can be easily installed and supported.

Fig. 9A, 9B and 9C are shown in schematic form, but in some alternative constructions, the leds 24 are suitably located at a distance from the waveguide apex. Fig. 9A depicts a light scattering spacer 48 between the waveguide 12 and the light emitting diode 24. Such a spacer 48 may be made of the same material as the waveguide, i.e. a high impact resistance acrylic material. Fig. 9B shows a configuration having a slot 18 sized so that the led abuts the inner surface of the slot and forms a gap 50 between the apex of the led lamp envelope and the waveguide 12. Fig. 3 illustrates the use of a transparent potting compound that fills the gap between the light emitting diode 24 and the waveguide 12. After the light emitting diodes 24 and the circuit board 36 are disposed therein, the compound can be easily introduced into the groove 18.

Fig. 10A and 10B illustrate the construction of a lighting device 10 that includes a waveguide and/or lamp housing that can be varied depending on the application of the lighting device. Fig. 10A depicts parallel sidewalls 20, 22 sharply merging into diverging sidewalls 23, 25 of waveguide 12. Fig. 10B shows a configuration in which the side walls 20, 22 gradually diverge and coincide with diverging side walls 23, 25 of the waveguide 12. Fig. 11 depicts a further variation of the lighting device 10 in which the single string discussed above may be replaced by multiple strings of leds. Various other elements, including reflective and absorptive layers, are not shown in the figures to preserve clarity of the figures.

Although it is preferred that the LEDs 24 be oriented in a vertical direction as shown in FIG. 3 to provide the most efficient light intensity along the light pattern, other placement may be used. Fig. 14 shows an example in which the position of the led is arranged inclined so that the central axis 50' of the led is at a predetermined angle X to the normal direction 50 of the central axis of the led perpendicular to the longitudinal axis 52. Fig. 15 shows the light emitting diode 24 with its apex disposed downward (vertically or obliquely) with respect to the length direction of the waveguide axis. The collection of light from the various reflective surfaces directs the light from the led 24 into the waveguide for scattering in the same manner as described above.

Fig. 16 depicts another configuration in which the envelope 110 of the led 120 or point source is directly bonded to the body of the waveguide 100, which has reflective and absorbing layers, not shown for clarity.

As technology has evolved, light sources may be made in elongated or rope form, for example as sheets of electroluminescent material juxtaposed alongside leaky waveguides with sufficient light intensity to replace strings of light emitting diodes. Fig. 17 shows such a configuration of the illumination device 140, with an elongated light source 170 extending in the envelope 160 parallel to the longitudinal axis of the waveguide 150.

The thin, Flexible Circuit board 26 is available from a variety of sources, such as Flexible Circuit Technologies (flexile Circuit Technologies), san Paul, Minn. The circuit and electrical connection characteristics on the circuit board 26 depend on the desired lighting sequence. Although the circuit is not part of the present invention, it should be noted that the structural features of the present invention allow for considerable sequence variation. In other words, the light weight of the lighting device, the ability to withstand the rigors of packaging, handling, transportation, installation, and the minimal heating of the lighting device provides the possibility of substantially unlimited lighting and color sequencing. For example, the circuit board may have various electrical components that allow the light source to blink and dim in a timed sequence to produce a motion effect. Various light source colors can be used and flashed/faded in almost any combination. If the different colors of the leds are staggered, a striped effect is obtained. Fig. 18 schematically shows a circuit that can be used in the present invention. A plurality of light emitting diodes 230 are shown connected in series to a remote power source 232, an NPN transistor 234, and the transistor 234 is connected to a programmable controller 236. A second set of light emitting diodes 240 and another set of light emitting diodes similarly connected to the power source 232, NPN transistor 242, and controller 236 may be grouped separately or alternated with the light emitting diodes 230 as desired. Using the above grouping, the controller 236 can be programmed to turn the transistors on or off, thereby pulsing or flashing the first and subsequent groups of leds to simulate motion. If the groups mounted on a device form a sequence of words, such as "drink cola", the words may flash in sequence. If the groups of leds alternate in position, the resulting groups may form a striped pattern of multiple colors.

From the above discussion, it should be appreciated that the lighting device of the present invention is robust and resistant to breakage during shipping and handling of the corresponding neon lighting device. The illumination source, preferably a solid state lighting device such as a light emitting diode, uses very little electrical energy and remains relatively cool to the touch. This allows the illumination device of the present invention to be used in applications where the heat generated by neon lighting limits its use. Moreover, the light weight of the lighting device facilitates installation on support structures that are not capable of supporting the relatively heavy weight of neon lighting devices, and the required accessories include high voltage infrastructure. Finally, the lighting device is flexible in use, allowing a wide variety of lighting technologies that are very difficult to obtain in neon lighting without substantial expense. Other advantages and uses of the invention will become apparent to those skilled in the art from a reading of the disclosure herein, and are intended to be covered by the claims set forth below.

Claims (31)

1. An illumination device for simulating neon lighting, comprising:

a generally rod-shaped element having a predetermined length and having a lateral light-receiving surface and a lateral curved light-emitting surface having a predetermined circumferential width, said element being constructed of a material having optical waveguide and light scattering properties which scatters light entering said light-receiving surface into an elongated intensity pattern on said light-emitting surface, the intensity pattern having a major axis extending along said predetermined length;

a plurality of spaced point light sources extending along and adjacent to said light receiving surface and spaced from said light emitting surface a sufficient distance such that said light intensity pattern on said emitting surface has a minor axis extending substantially the entire circumferential width of said light emitting surface;

a lamp housing in which the point light source is disposed, the lamp housing extending along the light receiving surface and having a pair of side walls, each side wall having an internal light reflecting surface and an external light absorbing surface; and

an electrical connection element located within the lamp housing and adapted to connect the point light source to a remote power source.

2. The illumination device of claim 1, wherein the point light sources are light emitting diodes.

3. A lighting device as recited in claim 2, wherein said light emitting diode has an elliptical shape with a major axis extending in the direction of said one line.

4. A lighting device as recited in claim 1, wherein said envelope comprises a flexible material and said electrical connection element is sufficiently flexible to be bent to conform to any non-linear shape defined by said envelope.

5. The lighting device of claim 1, comprising a light transmissive material filling the interior space of said envelope to maintain the position of said point light source and electrical connection elements in said envelope.

6. A lighting device as recited in claim 5, wherein said light transmissive material is transparent.

7. A lighting device as recited in claim 5, wherein said light transmissive material has light scattering properties.

8. A lighting device as recited in claim 5, wherein said point light source comprises a plurality of light emitting diodes and said light transmissive material has a refractive index which substantially matches a refractive index of a lamp envelope of said light emitting diodes to minimize Fresnel losses at an interface therebetween.

9. A lighting device as recited in claim 5, wherein said light transmissive material forms a bottom wall extending along said housing, said bottom wall having a light reflecting surface for reflecting light incident thereon into said rod-like member.

10. The illumination device of claim 1, including a light-transmissive divider positioned between and generally adjacent to said point light source and said light-receiving surface.

11. A lighting device as recited in claim 1, wherein said rod-like element and said lamp envelope are integral and comprise impact resistant acrylic.

12. A lighting device as recited in claim 2, wherein said light emitting diode has a lamp envelope disposed in a substantially vertical position relative to said light receiving surface, the apex of each lamp envelope being adjacent said light receiving surface of said rod-like member.

13. A lighting device as recited in claim 2, wherein said light emitting diode has a housing which is inclined with respect to the length of said rod-like member.

14. A lighting device as recited in claim 2, wherein said light emitting diode has a lamp housing disposed in an inverted position relative to said light receiving surface, said light emitting diode emitting light in a direction away from said light receiving surface.

15. An illumination device for simulating neon lighting, comprising:

a light-transmissive element having a predetermined length and having generally curved light-emitting and light-receiving surfaces, said element being comprised of a material having optical waveguide and light scattering properties which scatters light entering said light-receiving surface into an elongated light intensity pattern on said light-emitting surface, the pattern having a major axis extending along said predetermined length;

a lamp envelope having spaced apart side walls adjacent said light receiving surface and defining a space extending along said predetermined length of said light transmissive element, said side walls having light reflective interior surfaces and light absorbing exterior surfaces; and

a plurality of spaced point light sources located in said space and extending along said predetermined length, said spaced point light sources being spaced from said light emitting surface a distance sufficient to cause the intensity pattern from each point light source to overlap an adjacent intensity pattern such that the resultant emitted intensity pattern from said light emitting surface appears uniform.

16. A lighting device as recited in claim 15, wherein an inner surface of said side wall is covered with a light reflecting material and an outer surface thereof is covered with a light absorbing material.

17. A lighting device as claimed in claim 15, comprising a separating element of transparent material located in and filling a portion of the space between said point light source and said element.

18. The illumination device of claim 15 wherein the point light sources are light emitting diodes.

19. A lighting device as recited in claim 18, wherein said electrical component is connected to a programmed processor for causing said light emitting diodes to flash independently.

20. The illumination device of claim 19, wherein the leds flash in a time sequence.

21. The illumination device of claim 19, wherein the leds blink in successive groups along the length of the first string, thereby simulating motion.

22. A lighting device according to claim 21 comprising a plurality of leds mounted in a second string, said second string being located in said space and extending in the direction of extension of said envelope, said second string being connected to said electrical components so as to be independently energized.

23. A lighting device as recited in claim 21, wherein said light emitting diodes of said first string are disposed along a length of said lamp envelope alternately with said light emitting diodes of said second string.

24. A lighting device as recited in claim 22, wherein said light emitting diodes of said first string emit light of a different color than said light emitting diodes of said second string.

25. An illumination device for simulating neon lighting, comprising:

a substantially solid leaky waveguide rod having a predetermined length and having a lateral light receiving surface and a lateral light emitting surface;

a plurality of spaced apart point light sources extending substantially along the predetermined length of the light receiving surface and disposed adjacent to the light receiving surface for emitting a portion of the light emitted by the point light sources directly into the light receiving surface; and

a lamp envelope located outside and adjacent to said waveguide rod and defining a space around said point light source, whereby said lamp envelope comprises a side wall having a light reflective inner surface and is adapted to collect and direct light emitted by said point light source to said lateral light receiving surface such that light is directed along a predetermined length of the leaky waveguide rod away from said light emitting surface in an elongated light intensity pattern having a major axis extending along the length of said waveguide rod.

26. The illumination device of claim 25, further comprising a transparent material filling at least a portion of said space and abutting said light receiving surface and said point light source, said transparent material having a refractive index that reduces Fresnel (Fresnel) losses between said point light source and said waveguide.

27. The illumination device of claim 25 wherein the point light sources are light emitting diodes.

28. A lighting device as recited in claim 27, wherein said transparent material has an index of refraction which is substantially the same as an index of refraction of said waveguide and said lamp envelope of said light emitting diode.

29. A lighting device as recited in claim 27, wherein said light emitting diode is spaced from said light emission surface a sufficient distance to enable a light intensity pattern from each point source to overlap an adjacent light intensity pattern so that a resultant emitted light intensity pattern from said light emission surface appears uniform.

30. The illumination device of claim 25, wherein the waveguide is formed of acrylic having light scattering properties.

31. A lighting device as recited in claim 25, wherein said side wall has an outer light absorbing surface.