A led flexible strip device includes an elongated flexible tube with a translucent tube shell and opposed tube ends and a flexible circuit board set in the tube so that it extends between the tube ends. The flexible circuit board has opposed interior and exterior surfaces. Electrical circuitry is mounted to the circuit board and connected to an external input source and an output source of electrical power.
The circuit board defines a number of cut-outs, preferably those of a generally diamond shape. The device is described in two embodiments: one with inwardly directed LEDs on the circuit board directed into the tube and one with outwardly directed LEDs on the circuit board directed out of the tube. The method of making the led flexible strip device is also described.
led flexible strip strips, also called rope lights, are used for lighting both interior and exterior structures and can be used for sign applications. Existing lighting strips do not allow a combination of flexibility and rigidity desired byusers to configure rope lights into any selected configuration with ease. Color chasing and color mixing capabilities are limited.
Prior art in the sign industry includes the utilization of neon lamps, fluorescent lamps, and incandescent lamps. The drawbacks for neon and fluorescent lamps include difficulty in starting in cold temperatures, dangerous high-voltage operation,and the presence of mercury that in turn creates an environmental hazard. Incandescent lamps generate a large amount of heat, have poor resistance to vibration, have short lamp life, and consume large amounts of energy with the result that most of theirlight energy is wasted as infrared heat energy.
Light emitting diode (LED) technology makes possible the replacement of short lamp life with longer lamp life and energy deficient light sources using energy efficient light sources that are long lived and cooler running. Color output LEDs canemit red (R), green (G), blue (B), and yellow (Y) light, or white light. Brighter color mixing with better color rendering than in prior art technology is a result. Color additive mixing of LEDs can produce the secondary colors cyan (C), yellow (Y),magenta (M) and white light. Mixing green and blue gives cyan. Mixing green and red gives yellow. Mixing red and blue gives magenta. Mixing RGB plus a separate Y generates a truer white light with better color rendering than just combining RGB.
It is noted that color gel filters are not necessary with RGBY color mixing light technology, which in itself generates the full light spectrum. Color efficiency in LEDs is much better than incandescent filament lamps, which require a specificcolor gel or filter. This can waste up to about 90 percent of the light energy of incandescent lamps. LEDs on the other hand deliver 100 percent of their energy as light and further emit a more intense selected colored light. This energy efficiency ofLEDs extends to the emitting of white light as well. There are two ways of using LEDs to produce white light in this invention: 1) using LEDs that produce white light exclusively, or 2) using LEDs to emit RGBY at the same time and at equal outputintensities.
Besides generating less heat, LEDs are more energy efficient, more durable, and last longer than conventional light sources. The solid state design of LEDs makes them durable and robust and gives them the capability of withstanding shock,vibration, frequent power cycling and operation in extreme cold and hot temperatures. LEDs have an average usable life of typically 100,000 hours or more when operated within design specifications. LEDs are mercury free. LED technology now includesmulti-chip and multi-light LED arrays, so that LEDs are available in a wide range of colors in unique combinations. Clearly for many applications LEDs now compete directly with incandescent filament, neon, and fluorescent light sources.
In the preferred embodiment of the present invention, light emitting diodes in different colors can be mounted onto a flexible circuit board that is twisted into a helix and inserted into a flexible tubular housing. This unique combination of aflexible circuit board and a flexible tubular housing will allow for a more versatile and improved flexible shape retaining rope light and cove light. In addition, the ease of manufacturability and full 360-degree omni-directional and uniform lightdispersion is very important.
In an alternate embodiment of the present invention, light emitting diodes in white and different colors are mounted onto a flat long flexible circuit board with multiple repeating cutouts preferably diamond shaped that extend through the circuitboard substrate. The circuit board is then rolled into a cylinder with the LEDs mounted to the interior of the circuit board and pointing inwards into the cylinder or alternatively, the LEDs are mounted to the exterior of the circuit board and pointingoutwards from the cylinder, or both. The entire cylindrical assembly is inserted into a flexible outer tubular housing. A stiffening member contained in the outer tubular housing and optionally on the flexible circuit board itself will allow thecomplete LED lighting strip to be flexible because of the diamond shaped cutouts provided on the flexible circuit board, and will allow for some rigidity and memory for proper installation and assembly of the complete led flexible strip strip. Thisunique combination of a flexible circuit board and a flexible tubular housing will allow for a more versatile and improved flexible shape retaining rope light, cove light, and signage light. In addition, this invention has ease of manufacturability andfull 360-degree omni-directional and uniform light dispersion that is very important. Previous inventions have been developed to try and accomplish this task, but have not been successful.
Color Kinetic's iColor Accent, Cove, and Fresco line of LED fixtures are available only in rigid linear transparent or translucent housings that offer no flexibility or versatility at all. To achieve a circular arrangement, for example, multiplelinear fixtures have to be aligned edge to edge to approximate the curved outline. The iColor Accent, Cove, and Fresco fixtures also use rigid circuit boards with the LEDs mounted perpendicular to the circuit boards, therefore the light dispersionoutput from the LEDs are generally in the forward direction offering only at most approximately 180 degrees of coverage.
An object of the present invention is to provide a led flexible strip that can accomplish the functions of known rope lights, cove lighting, and signage lighting with greater energy efficiency and omni-directional light dispersion withcolor mixing, color changing, and color chasing capabilities.