This invention relates to fluorescent lamps and more particularly to highly loaded lamps, especially for those used in UV tanning booths.
Hot cathode fluorescent lamps are subject to end blackening due to the deposition of sputtered and evaporated compounds from the electrodes depositing upon the cooler ends of the lamp envelope during operation of the lamps. While these deposits do not normally effect the proper functioning of the lamp, nevertheless, in some instances the aesthetic effect of the lamp is impaired.
To prevent or at least reduce the amount of the blackening it has been proposed to shield the electrodes. Shields, both electrically insulated and electrically active have been proposed. See, for example, U.S. Pat. Nos. 4,891,551; 5,004,949; 6,741,023; and 6,809,468. While at least partially effective for their intended purpose, these shields have been cumbersome, expensive and difficult to mount, in some instances requiring an extra support sealed into the glass base (U.S. Pat. Nos. 4,891,551 and 5,004,949) and in other instances requiring a large cup-shaped shield that is difficult to manufacture and that, when installed, casts an objectionable shadow upon the lamp envelope (U.S. Pat. Nos. 6,741,023 and 6,809,468).
It is, therefore, an object of the invention to obviate the disadvantages of the prior art.
It is another object of the invention to enhance fluorescent lamps.
It is another object of the invention to enhance fluorescent lamp shielding.
Yet another object of the invention is the provision of a simple and convenient shield that does not require extra support members inserted into the glass base and that is suited to automatable assembly.
These objects are accomplished, in one aspect of the invention, by a fluorescent lamp that includes an elongated glass envelope; a mount structure sealing each end of the envelope, each of the mount structures having a glass base; two spaced apart lead-in wires sealed into the glass base and extending into the envelope; an electrode connected between the lead-in wires within the envelope; and an electrode shield surrounding the electrode, the electrode shield being substantially equidistantly spaced from the electrode; and wherein the improvement comprises a support member attached only to the shield and to one of the lead-ins.
This electrically active shield does not require extra support units sealed into the glass base and delivers more light to the end of the lamp than the cumbersome cup-shaped shields.
For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims taken in conjunction with the above-described drawings.
Referring now to the drawings with greater particularity, the is shown in
The mount structure 14 is shown enlarged in
In a preferred embodiment of the invention the shield 26 is constructed from a material having a thickness of from 0.15 mm to 0.25 mm and selected from cold rolled steel, nickel or nickel-plated steel, with nickel-plated steel being preferred, and the support member 28 is selected to have the same properties as the shield, for example, nickel-plated steel wire having a diameter of 0.30 inches (0.823 mm). Preferably, the support member 28 is welded to the shield wall 26c and one of the lead-in wires.
In an alternate form of the invention, the shield wall 26c can be provided with a perforation tab 30, as seen in
The efficacy of the end brightness of the instant invention compared to the end brightness of one of the cup-shaped shields of the prior art is shown by the graph of
And, of course, relative to the similar shields of the prior art, this invention adds simplicity, the convenience of automation capabilities, and the elimination of the sealed-in support member, which latter provision strengthens the glass seal and eliminates a potential leakage site.
While there have been shown and described what are present considered to be the preferred embodiments of the invention, it will be apparent to those skilled in the art that various changes and modifications can be made herein without departing from the scope of the invention as defined by the appended claims.