Patent Application
20090134763
The present invention relates to the field of incandescent lamps, 3-way incandescent lamps and more specifically parabolic reflector lamps known as PAR lamps, commonly used in residential and commercial buildings.
Parabolic reflector lamps are the most popular lamps used in general lighting for commercial buildings. They are usually identified in the lighting industry as “PAR” lamps, in which a light source, such as an incandescent filament or gas-discharge capsule is oriented at the focal point of a parabolic reflector. Such PAR lamps employ integral screw bases or bi-pin bases that are supported within lamp sockets connected to remote sources of electrical power.
The reflectors of PAR lamps are normally classified by reflector rim diameter, such as MR-16 (Miniature Reflector, 16 ⅛ths of an inch, or 2-inches in diameter) as shown in Prior art
Over recent years parlamps have grown in popularity, compared to fluorescent lamps, because their light sources (incandescent filaments) are small enough to be sharply focused. The MR-16 lamp is widely used because it can be made in a 10° or 20° spotlight that fits in small downlights and tracklights. The typical filament structure of a tungsten-halogen light capsule used in an MR-16 is shown in
In lamps having large reflectors, such as the prior art PAR 38 lamp of
In the quest for less energy use, many incandescent lighting systems, using inexpensive lamps, employ dimmers that reduce the light output of the lamp. This an ineffective method, as a 50% reduction in light output reduces the filament temperature, shifting more lamp energy into the infrared band. Thus dimming the light by 50% only reduces the power consumption by 10%. Further, the dimmed light becomes more yellow-orange in color. Since human eyes see most efficiently in the green portion of the visible spectrum at 560 nm (nanometer wavelength), dimming results in poor visual efficiency. Then the energy saving is often offset by turning up the light level.
Residential use of 3-way incandescent lamps maintains the color temperature of the light by using 2 filaments of unequal wattage that are illuminated separately or together, usually at 30-60-100 watts. The light levels are changed by a rotary switch in portable lamps, such as table lamps or floor lamps. However these are only currently available as A-type lamps having the typical “light bulb” spherical-end shape, and thus are used almost exclusively in a lamps in private residences.
One energy-saving light source is the self-ballasted, screw-base, compact fluorescent lamp that screws directly into a medium screw-base socket. This applicant is very familiar with such products as the inventor of the energy-efficient circuline fluorescent converters shown in U.S. Pat. Nos. 4,161,020; 4,420,799; 4,105,276; 3,432,723; 4,349,768; and D-215,480; 3-way fluorescent converters U.S. Pat. No. 4,178,535; and U.S. Pat. No. 4,367,434. These patents date back 30 years, and the products were sold in retail stores. However cheap energy at the time limited sales of converters costing many times more than an ordinary light bulbs.
Now the high cost of energy dictates a need for energy conservation and justifies the added expense of the currently-available spiral-tube compact fluorescent lamps. The return on investment in lamps is acceptable in commercial buildings using hundreds or even thousands of downlight and/or tracklights. These lamps are very efficient in terms of lumens per watt, but the relatively large luminous areas of “compact” fluorescent lamps are not all that compact, and thus cannot be focused or aimed effectively. The result is an overall “wash” of relative bright light that often under-illuminates task areas, while over-lighting unoccupied open areas including the floors.
Human vision is not directly proportional to light levels, but is also dependent on a factor called “CRI” (Color Rendition Index). A perfect CRI rating of 100 means that an average person viewing an array of color sample chips of graduated colors, can correctly place 100% of the chips in their correct sequence in the color spectrum. An incandescent light source has a continuous, uninterrrupted SPD (Spectral Power Distribution) with no gaps in its spectral output from the UV (ultravionet) limit at 380 nm wavelength, through the visible spectrum, to the IR (infrared) limit at 770 nm.
However, in the quest for high lumens per watt, fluoreescent lamps are designed as “tri-stimulus” lamps that stimulate each of three separate color sensors in the human eye. The gaps between the three spikes of fluorescent light output provide a CRI of only about 80, meaning that a person can only correctly place 80% of the test chips in their correct order in the spectrum. Thus human visual efficiency is about 20% lower with fluorescent light than incandescent light.
Further, fluorescent lamps, and particularly high-output spiral compact fluorescent lamp, are based on mercury emissions used to energize those tri-stimulus light-emitting phosphors. Thus the lamps emit about 6% of their total output as ultraviolet energy and approximately 70% of their energy as IR heat. These invisible “light” bands are known to cause photochemical damage to everything from textiles to meats and bananas, while contributing nothing to vision.
The shortcomings of fluorescent lamps raises the need for full-spectrum incandescent lamps that can have remotely switched 3-way operation using 2 small filament light sources, such as the present invention as shown in
The present invention as shown in
The tungsten-halogen lamp (2) has a first incandescent filament (12) on the optical axis, with a proximal end connected to the center contact of the lamp base and extending on the optical axis in the distal direction to a distal end support (13) and having an LCL (light center line) approximately at the focus (4) of reflector (3). Distal end support (13) is electrically connected to neutral male screw shell (9).
A second incandescent filament (14) on the optical axis has a proximal end first filament support (12) at the distal end of the first filament and extends in the distal direction on the optical axis, with an LCL (15) displaced from the focus of the reflector and having a distal end supported and connected to second filament support (16), connected to the intermediate contact (11) of the lamp base.
In
Prior art
A 3-way reflector lamp (1) according to the invention includes a parabolic reflector (3) mounted on a 3-way lamp base (7) having screw shell (9), a center contact (10) and an intermediate contact (11). The reflector has its focus on an optical axis (5) with a proximal end at the reflector focus (4) and extending in the distal direction. A first filament (12) is connected to the screw shell and center contact, whereby light from the first filament is collimated by the reflector into a spotlight beam, and a second filament (14) on the optical axis is spaced in the distal direction from first filament (12) and connected to screw shell (9) and an intermediate ring contact (11), whereby light from energized second filament (14) is diffused into a floodlight beam.
