1. Technical Field
The present invention generally relates to a luminaire including a light-emitting panel, particularly to a luminaire utilizing light emitting diodes.
2. Description of Related Art
Light-emitting panels are commonly used in luminous signs for advertising purposes. Light of the conventional light-emitting panels is provided by a tubular low-pressure mercury-vapor discharge lamp, for example a cold cathode fluorescent lamp (CCFL). However, the CCFL having hydrargyrum is harmful to the environment.
Light emitting diodes (LEDs), on the other hand, have many advantages, such as high luminance, low power consumption, highly compatible with integrated circuits, long-term reliability and environmental friendliness and are becoming widely used as light sources instead of CCFLs, as described in an article entitled “Solid-State Lighting: Toward Superior Illumination” cited in a publication of Proceedings of the IEEE, Vol. 93, No. 10, October, 2005 authored by Michael S. Shur.
U.S. Pat. No. 6,539,656 discloses a luminaire with LEDs used as light sources. The luminaire includes a light-emitting panel. Light originating from the light sources is guided in the panel by a plurality of deformities defined in the panel. The deformities are arranged in a pattern to form at least one light symbol and include a first cluster and a second cluster of deformities. Preferably, the luminaire has a first and a second light-transmitting edge surfaces, respectively, associated with a first and a second light sources having LEDs. The first cluster of deformities is used to guide light from the first light source in a horizontal direction out of the panel, thereby forming a first light symbol, while the second cluster of deformities guides light from the second light source in a vertical direction out of the panel, thereby forming a second light symbol. Thus, the two symbols can be selectively and alternatively lit up. The luminaire provides independent lighting and coloring possibilities of light symbols in a single-panel luminaire.
However, in order to illuminate the symbols with different colors, either of the light sources must includes LEDs emitted a desired color. When a different color is desired, the LEDs must be correspondingly replaced with LEDs of the new desired color. Furthermore, in the daytime, sunlight may cause both of the symbols to light up at the same time, resulting in difficulties to viewers in recognizing or distinguishing the symbols.
Accordingly, what is desired, therefore, is a luminaire having a light-emitting panel which overcomes the above shortcomings.
The present invention provides a luminaire including a light source providing white light and a light-emitting panel. The light-emitting panel includes a light emission surface and a light incidence surface. A plurality of deformities are formed in the light emission surface. Some of the deformities are applied by dye material. The dye material can filter light having the same color from the white light. The deformities that are chosen for staining/coloring conform to a desired pattern to form an image on the light emission surface.
Other advantages and novel features of the present luminaire will become more apparent from the following detailed description of present embodiments when taken in conjunction with the accompanying drawings.
Referring to
In operation, light originating from the light source 51 is guided into the panel 52 via one of the edge surfaces 55 which serves as a light incidence surface adjacent to the light emission surface 53. In accordance with the principle of total internal reflection, the light continues to move back and forth in the panel 52 until the light is reflected to the recesses 56. The recesses 56 serve as a means for guiding light out of the panel 52 via the light emission surface 53. The shape of each of the recesses 56 is favorably chosen from the group including triangular prism, tetrahedron, quadrilateral pyramid, truncated cone, a cube and hemispheroid. Such shapes are suitable for guiding light out of the panel 52 in various ways. The recesses 56 break up the smooth light emission surface 53 such that the internal angle of reflection of a portion of the light rays will be great enough to cause the light rays to be eventually guided out of the panel 52 through the light emission surface 53.
Referring to
The recesses 561 having red dye material 58 are arranged so as to form at least one light symbol 59 (for example the letter “O”) in the light emission surface 53 of the panel 52. The recesses 561 can be selectively illuminated to light up the light symbol 59. When the light source 51 emits the white light, red light ray of the white light are guided out of the panel 52 via the red dye material 58 to illuminate the light symbol 59 so that the light symbol 59 of “O” can be clearly visible. Furthermore, the recesses 561 can be arranged to form other symbols such as text, graphics, logo, letter, image or combination of the above with any color. In the daytime, sunlight can be used as an alternative light source for the panel 52 so that power can be saved.
The bottom surface 54 can be preferably provided with a reflecting coating 57 made with a material having high reflectivity, such as mercury, aluminium, silver, gold or copper, to hold the light originating from the light source 51 inside the panel 52.
The dye material 58 of the recesses 561 can removed and then reapplied to form new patterns in one or many colors thus saving money by eliminating the need to replace expensive parts of the panel 52.
The recesses 56 can be achieved by one of the following semiconductor manufacture technics, such as etching machining, laser beam machining, impression machining or the like. The etching machining has following steps comprising: (1) covering a protective film on an area the light emission surface; (2) plate making and developing via exposure, then remove the protective film; (3) pouring chemical liquor to the area covered by the protective film to dissolve the light emission surface so as to form the recesses 56.
The laser beam machining serves as a means for employing laser with high energy density to irradiate the light emission surface so as to form the recesses 56. An injection machining can also used to form the recesses 56 by injecting mixture having particles of PMMA and a few other particles having different refractive index into the mold, at high temperature and pressure.
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It is to be understood that panel of luminaire can employ deformities constructed by recesses and protrusions, which are arranged in a pattern to form a light symbol.
Number | Date | Country | Kind |
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200710203422.9 | Dec 2007 | CN | national |