Electric lamp and discharge devices: systems – Plural power supplies – Plural cathode and/or anode load device
Reexamination Certificate
2000-05-12
2001-07-03
Wong, Don (Department: 2821)
Electric lamp and discharge devices: systems
Plural power supplies
Plural cathode and/or anode load device
C313S568000, C313S576000, C313S581000, C362S260000, C363S071000
Reexamination Certificate
active
06255782
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a flat type fluorescent lamp for use in a device such as a transparent type liquid crystal display, specifically for use as a back light thereof, in particular, where no memory is used therein.
2. Description of Prior Art
In a flat type fluorescent lamp of the conventional art, using no mercury therein, as shown in FIGS.
6
(
a
) and (
b
), a pair of electrodes
102
and
103
, each being coated with a dielectric material, are positioned within a sealed container, which is formed by hermetically bonding a transparent front substrate
100
and a rear substrate
101
together, wherein a fluorescent material is applied upon the inner surfaces of the front substrate
100
and the rear substrate
101
, and Xe (xenon) gas is contained within the sealed container.
High voltage is applied between the electrodes
102
and
103
to cause dielectric barrier discharge, thereby atoms of the xenon gas, being excited or energized, irradiate ultraviolet rays therefrom. Receiving the ultraviolet rays, the fluorescent material, being of a three-color combination, converts the ultraviolet emission into visible light of red, green and blue colors, thereby achieving a function as a white color fluorescent lamp.
However, with such a flat type fluorescent lamp, the discharge occurs locally as opposed to uniformly if the distance between the electrodes is made large so as to obtain a large discharge area, therefore it is impossible to obtain a uniform fluorescence over the surface thereof. Because of this, for achieving a flat fluorescent lamp having large area, it is essential to newly devise the structure of the electrodes thereof.
Also, for the lamps having or using no mercury therein, a manner for increasing an efficiency of brightness comes to be a substantial challenge.
Further, the flat type fluorescent lamp, in particular, for use as a back light to be installed in a device such as a car navigation system, is required to be of high brightness, so that the display can be seen even in bright daylight surroundings, while it is required to be adjustable in the light amount emitted therefrom down to, for example, 3% of maximum radiation, in order to adjust for the greatly lesser light levels present inside of the car operated when driving during the night.
SUMMARY OF THE INVENTION
An object of the present invention, for dissolving drawbacks of the conventional arts mentioned above, is to provide a flat type fluorescent lamp, wherein the structure of the electrodes and the voltage waveforms applied thereto are newly devised, to thereby obtain an improvement in the efficiency of brightness while maintaining uniform emission of light, and further enabling a broad range of control of the amount of light irradiated therefrom.
According to the present invention, for accomplishing the object mentioned above, there is provided a flat type fluorescent lamp, which produces light with no use of mercury therein, comprising:
a sealed container being defined between a front substrate and a rear substrate which are hermetically bonded to each other, so as to enclosed a rare gas as discharge gas therein;
edge electrodes being provided at both end portions on a surface of said sealed container;
other edge electrodes being provided at both end portions on the other surface of said sealed container, wherein the edge electrodes on the same side surfaces are connected to each other, respectively;
a first inverter being connected between one of said edge electrodes and a central electrode which is provided in a central portion of said one of the surfaces; and
a second inverter being connected between the other of said edge electrodes and said central electrode, wherein said first inverter and said second inverter provide rectangular waveform outputs, being same in frequency thereof and having phases different to each other, thereby energizing the lamp.
Also, according to the present invention, in the flat type fluorescent lamp as defined in the above, one belt-like electrode is provided between each of both edge electrodes on said surface and said central electrode, while three belt-like electrodes are provided between said other edge electrodes on said other surface, wherein a width of the belt-like electrode that is positioned at a middle among said electrodes lies within a region within ±1 mm with respect to the width of said central electrode, and there are defined distances between said electrodes, respectively.
Further, according to the present invention, in the flat type fluorescent lamp as defined in the above, the distances between said electrodes lie from 2 mm to 4 mm.
According to the present invention, in the flat type fluorescent lamp as defined in the above, all of the electrodes on said surface are connected to one another, while all of the electrodes on said other surface are connected to one another, and either said first inverter or said second inverter is connected between them.
According to the present invention, in the flat type fluorescent lamp as defined in the above, the thickness of each of said substrate is from 1.1 mm to 4 mm.
According to the present invention, in the flat type fluorescent lamp as defined in the above, the thickness of a discharge space defined therein is from 1.3 mm to 4 mm.
According to the present invention, in the flat type fluorescent lamp as defined in the above, pressure of the gas is set from 150 torr to 400 torr, and partial pressure of an excitation gas is from 7.5% to 30%.
REFERENCES:
patent: 4882520 (1989-11-01), Tsunekawa et al.
patent: 5008789 (1991-04-01), Arai et al.
patent: 5220442 (1993-06-01), Dingwall et al.
patent: 5245525 (1993-09-01), Galloway et al.
patent: 5272419 (1993-12-01), Park
patent: 5280221 (1994-01-01), Okamoto et al.
patent: 5307188 (1994-04-01), Dingwall et al.
patent: 5391965 (1995-02-01), Teva
patent: 5825345 (1998-10-01), Takahama et al.
patent: 5920155 (1999-07-01), Kanda et al.
patent: 5965988 (1999-10-01), Volkommer et al.
patent: 6081076 (2000-06-01), Ogawa
Kuroda Yasunao
Matsumoto Ken'ichiro
Ozaki Mitsuya
Merchant & Gould P.C.
Nippon Sheet Glass Co. Ltd.
Tran Thuy Vinh
Wong Don
LandOfFree
Flat type fluorescent lamp does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Flat type fluorescent lamp, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flat type fluorescent lamp will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2566575