Electric lamp and discharge devices: systems – Combined load device or load device temperature modifying... – Discharge device load
Reexamination Certificate
2002-05-21
2003-12-02
Phan, Tho (Department: 2821)
Electric lamp and discharge devices: systems
Combined load device or load device temperature modifying...
Discharge device load
C315S056000, C313S491000
Reexamination Certificate
active
06657392
ABSTRACT:
TECHNICAL FIELD
The present invention relates to discharge lamps that are designed for dielectrically impeded discharges and are also designated as silent discharge lamps. Such discharge lamps have an electrode set for producing discharges in a discharge medium that is located in a discharge space of the lamp. Provided in this case between at least one part of the electrode set and the discharge medium is a dielectric layer that forms the dielectric impediment. In the case of lamps in which it is fixed whether the electrodes operate as cathodes or anodes, at least the anodes are dielectrically separated from the discharge medium.
BACKGROUND ART
Such lamps are prior art and have recently been enjoying increasing attention, chiefly because it is possible with the aid of a pulsed mode of operation (U.S. Pat. No. 5,604,410) to achieve relatively high efficiencies that make use as a source of visible light or as a UV radiator seem attractive for various fields of application. Of particular interest in this case are lamps in which the discharge space is located between two generally plane-parallel plates that are denoted below as base plate and as top plate. In this arrangement, at least the top plate is at least partially transparent, being capable, of course, of bearing on its side facing the discharge space a fluorescent material that is not itself transparent in the true sense. Such lamps with a plate-like design are of interest chiefly as flat discharge lamps, for example, for backlighting purposes in the case of displays, monitors and the like.
In order to ensure sufficient stability in the case of relatively large lamp formats, it is possible to use between the base plate and the top plate support elements that are located inside the discharge space and connect the base plate and the top plate to one another. In the outer region, the plates can be connected via a frame that encloses the discharge space and is not denoted here as a support element. The support elements shorten the bending length between the outer edges of the plates in the region of which the frame described can be provided, and thereby improve the stability of the lamp against bending loads and compressive loads. It is also to be borne in mind in this case that silent discharge lamps are frequently filled with a discharge medium exhibiting low pressure such that a generally relatively large part of the external atmospheric pressure bears on the plates.
DISCLOSURE OF THE INVENTION
Starting from this prior art, the invention is based on the technical problem of specifying a silent discharge lamp of the type described having improved support elements.
The invention therefore provides: a discharge lamp having a base plate, a top plate for the light exit, which is at least partially transparent, a discharge space between the base plate and the top plate for holding a discharge medium, an electrode set for producing dielectrically impeded discharges in the discharge medium, a dielectric layer between at least one part of the electrode set and the discharge medium, and at least one support element which produces a connection between the base plate and the top plate, characterized in that the support element is a supporting projection which is constructed as a unipartite component of the top plate, and the outer contour of the supporting projection tapers in the direction from the top plate toward the base plate in at least one cutting plane perpendicular to the base plate.
The invention further relates to a display device with such a discharge lamp and thus, for example, a flat display screen, a display or the like using LCD technology.
In a departure from the relevant prior art, in which the support elements are placed as separate glass balls between the plates, the invention firstly adopts the approach of constructing the support elements as integrated components of the top plate. These are thus projections of the top plate that are directed toward the base plate and are a unipartite component of the top plate. The top plate is preferably already produced with these projections with the aid of a suitable shaping method, for example thermoformed or compression-molded. However, the projections can also be integrally formed subsequently. It is, however, essential that when assembling the lamp the top plate has supporting projections that are designed in a unipartite fashion with it. The outlay on the positioning and fixing of separate support elements between the plates should then be eliminated during assembly of the lamp. However, for example, it can also be sensible for the purpose of fastening the support projections on the base plate to provide a connecting element—made from solder glass, for example—between the base plate and the supporting projections.
Furthermore, the invention is based on the idea that a unipartite construction of spacer elements with the base plate, which arises as development from the conventional supporting balls to be connected to the base plate is more unfavorable because the contact between the support elements and the plates produces shadows in the luminance distribution that impair the homogeneity. It has emerged that these shadows are more pronounced the smaller the distance of the contacts causing the shadows from the light-emitting plane of the top plate. It is therefore regarded as more favorable not actually to avoid such contacts completely, but to arrange them situated as deeply as possible, that is to say remote from the light-emitting side. By this means, the shadows merge to a greater extent in the luminance distribution of the lamp, particularly when diffusers or other elements homogenizing the luminance are also used on the top side of, or above, the top plate. The larger the distance between such diffusers and similar elements and the structures causing shadows, the more effectively it is possible to distribute the shadows extensively or resolve them again.
The invention also provides that the supporting projections extend out from the top plate toward the base plate in a tapering shape. The tapering is intended in this case to occur in at least one cross-sectional plane that runs through the supporting projection perpendicular to the base plate. In this arrangement the plates need not necessarily be plane and parallel to one another. The term “perpendicular” is to be understood locally, as appropriate. Tapering means that the extent of the supporting projection in the direction along the plates (“along” is also to be understood locally, as appropriate) in the cross-sectional surface in the region just above the base plate is smaller than in a region further removed from the base plate. The supporting projection is therefore intended to be narrower in the direction of the base plate. In this case, the tapering can preferably encompass the entire height of the supporting projection.
Various advantages, which need not necessarily be present in parallel, can be achieved through this shaping. Firstly, narrower supporting projections produce smaller shadow effects in the region of contact with the base plate. Secondly, in any case when individual localized discharge structures are produced over the base plate with the aid of the pulsed operating method, these discharge structures can be distributed over the base plate largely without being influenced by the supporting projections when the lamp is being designed. It is possible for this reason to achieve a good degree of homogeneity of the luminance and a relatively dense arrangement with the discharge structures. Thirdly, such forms of supporting points can also be important for optical properties of the top plate, as will become even clearer in the following course of the description.
The basic idea of the invention is directed to the structure of an individual supporting projection. Of course, the invention preferably relates to discharge lamps having a multiplicity of supporting projections. In particular, there is no mandatory aim of the invention to keep the number of supporting projections as low as possible, as is the
Hitzschke Lothar
Vollkommer Frank
Clark Robert F.
Patent-Treuhand-Gesellschaft fuer Elektrische Gluehlampen mBH
Phan Tho
LandOfFree
Discharge lamp for dielectrically impeded discharges... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Discharge lamp for dielectrically impeded discharges..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Discharge lamp for dielectrically impeded discharges... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3169654