Low-pressure mercury vapor discharge lamp with a spiral-shaped electrode shield
AssigneeKoninklüke Phillips Electronics NY
InventorsJohannes H. Roes, Adrianus J. H. P. Van Der Pol
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Abstract
The discharge vessel encloses a discharge space provided with a filling of mercury and a rare gas in a gastight manner. Each end portion (12a) of the lamp supports an electrode (20a) arranged in the discharge space. An electrode shield (22a) encompasses at least one of the electrodes (20a) and has a substantially spiral-shaped cross-section. Preferably, the electrode shield (22a) is made from a ceramic material and is covered with a material which reacts with or forms an alloy with alkaline earth metals released by the electrode (20a).
Claims17
A low-pressure mercury vapor discharge lamp provided with a discharge vessel,
- which discharge vessel surrounds in a gastight manner a discharge space provided with a filling of mercury and a rare gas,
- electrodes being arranged in the discharge space for generating and maintaining a discharge in the discharge space, and
- an electrode shield surrounding at least one of the electrodes at least substantially,
- the electrode shield forming a coil, the coil having a substantially spiral-shaped cross-section with an open space between an inner wall and an outer wall, said electrode being within said coil of the electrode shield.
A low-pressure mercury vapor discharge lamp provided with a discharge vessel,
- which discharge vessel has a longitudinal axis and encloses in a gastight manner a discharge space provided with a filling of mercury and a rare gas,
- electrodes for generating and maintaining a discharge in the discharge space, at least one of the electrodes having an electode shield and being arranged in the discharge space with a length transverse to the longitudinal axis, and
- the electrode shield enclosing the shielded electrode on a first side of the electrode which faces another of the electrodes and a second side of the electrode which is opposite the first side, and
- wherein the electrode shield has a substantially spiral-shaped cross-section.
A low-pressure mercury vapor discharge lamp provided with a discharge vessel,
- which discharge vessel surrounds in a gastight manner a discharge space provided with a filling of mercury and a rare gas,
- electrodes being arranged in the discharge space for generating and maintaining a discharge in the discharge space, and
- an electrode shield surrounding at least one of the electrodes at least substantially,
- wherein the electrode shield has a substantially spiral-shaped cross-section, and
- wherein the electrode shield surrounds sides of said at least one of the electrodes which face toward and away from another of said electrodes.
A low-pressure mercury vapor discharge lamp comprising:
- a discharge vessel having side walls along a longitudinal axis of the discharge vessel, said discharge vessel enclosing a discharge space having a filling configured to facilitate a discharge in the discharge space;
- at least one electrode for generating and maintaining the discharge in the discharge space;
- and
- a cylindrical shield having a substantially spiral-shaped cross-section and surrounding the electrode, wherein said cylindrical shield has open ends facing said side walls.
A low-pressure mercury vapor discharge lamp provided with a discharge vessel,
- which discharge vessel has an inside wall and encloses in a gastight manner a discharge space provided with a filling of mercury and a rare gas,
- electrodes for generating and maintaining a discharge in the discharge space, at least one of the electrodes including an emitter material and having an electrode shield,
- wherein the emitter material is substantially blocked from view by the electrode shield as viewed from the inside wall of the discharge vessel, and
- wherein the electrode shield has a substantially spiral-shaped cross-section.
Dependencies are inferred from the claim text.