Abstract:
A device and a method for the control of a gas discharge lamp are disclosed. In order to detract as little as possible from lamp life in spite of the luminous flux requirements to be fulfilled during the run-up of the lamp, the lamp is operated with an alternating current in a run-up phase which comprises at least the interval from 1 s to 3 s after lamp ignition, the amplitude of said current rising during the run-up phase. After the rise in the run-up phase, the current may first rise further or remain constant in a transitional phase which preferably follows the former phase, and is subsequently reduced until the lamp enters the stationary operational phase. The time gradient of the current is preferably chosen such here that minimum values for the luminous flux of the lamp are achieved at given moments. Particular advantages are obtained, for example, in the case of Hg-free lamps which are operated with high currents, especially during the run-up.
Abstract:
A high-pressure gas discharge lamp (HID [high intensity discharge] lamp) is described which is free from mercury and suitable in particular for use in automotive technology. The lamp is particularly remarkable in that a rise in temperature of the coldest (lowermost) bottom regions (10) is achieved by an asymmetrical electrode arrangement, such that the light-generating substances accumulated in said regions enter the gas phase in a sufficient quantity upon switching-on of the lamp. The temperature of the hottest (uppermost) wall regions (13) is not raised thereby, indeed, it may even be reduced. An essential advantage of this lamp is that its external shape, its dimensions, and the electrodes (3) themselves need not be changed when the lamp is operated in a horizontal position with vertically aligned pinches (5), while the electrodes (3) are fastened each to a metal foil (4) in a suitable downwardly-shifted position.
Abstract:
A high-pressure gas discharge lamp (HID [high intensity discharge] lamp) is described which is designed in particular so as to be free from mercury and suitable for use in automobile technology. To achieve improved lamp properties, in particular a substantially equal luminous efficacy compared with lamps of the same power and having a gas filling with mercury, as well as a burning voltage which is as high as possible, a geometry is proposed for the discharge space (2) which raises the temperature of the coldest spot in the lamp to such a degree that the light-generating substances can enter the gas phase to a sufficient extent also without mercury, and in particular in combination with the use of a metal halide as a voltage gradient generator.
Abstract:
A lighting assembly (100) includes an electronic driver circuit (110) and a discharge lamp (10). The discharge lamp (10) is driven with a steady-state average power of 20-30 W. It includes a discharge vessel (20) of a maximum inner dimension ID of less than 3 mm with two electrodes (24). A discharge vessel filling comprises a rare gas and a metal halide composition provided in an amount per volume of the discharge vessel (20) of less than 13.2 μg/μl. Electrical energy is supplied as an alternating current IL where pulses (150a-150d) are superimposed. The pulses occur in a time interval of 20% of a half-cycle time before or after a polarity change of the alternating current IL. During the pulses the current IL reaches the current value of at least 1.2 times the RMS value of the current IL.
Abstract:
A discharge lamp comprises a discharge vessel 20 defining a sealed inner discharge space 22 with two electrodes 24. A filling consists of a rare gas and a metal halide composition and is free of mercury. The discharge vessel 20 comprises outer grooves 36 where the electrodes 24 are embedded, arranged at a groove distance Ra between them. The discharge vessel 20 further comprises an inner diameter ID. In operation of the lamp, an arc discharge is formed between the electrodes and the metal halide composition is partly evaporated. After operation of the lamp, the metal halide composition forms a film on the inner wall of the discharge vessel 20. This film has a surface area AS measured in mm2. The metal halide composition is provided in such an amount within the discharge space 22, that a matching quotient Q, calculated as Q=Ra×ID/AS has a value of 2 or more, such that a high color temperature is achieved.
Abstract:
The invention describes a method of driving a gas-discharge lamp (1) according to conditions in a specific region (R) of the lamp (1), which gas-discharge lamp (1) comprises a burner (2) in which a first electrode (4) and a second electrode (5) are arranged on either side of a discharge gap, which lamp (1) is realised such that the position (PCs) of a coldest spot during an AC mode of operation is in the vicinity of the first electrode (4), which method comprises the steps of initially driving the lamp (1) in the AC mode of operation; monitoring an environment variable of the lamp (1), which environment variable is indicative of conditions in a specific region (R) of the lamp (1); switching to a temporary DC mode of operation at a DC power value on the basis of the monitored environment variable, whereby the first electrode (4) is allocated as the anode; and driving the lamp (1) in the DC mode of operation until the monitored environment variable has returned to an intermediate environment variable threshold value (TDCAC). The invention also describes a gas-discharge lamp and a driver for a gas-discharge lamp.
Abstract:
The invention describes a gas-discharge lamp (1) comprising a vessel (5), which vessel is partially coated with an essentially rectangular stripe (Sv) arranged circumferentially on a surface of the vessel, and wherein a first long side (14) of the stripe is situated close to a base (6) of the lamp, and the width (wv) of the stripe is such that a first angle (αv2) subtended at a lamp center between a radius (r) and a point on the first long side (14) of the stripe comprises at most 55°, and a second angle (αv1) subtended at the lamp center between the radius and a point on a second long side (15) of the stripe comprises at most 50°. The invention also describes a reflector for a lamp, comprising a reflective interior surface realized to deflect light originating from the lamp outward to give a specific beam profile with a bright/dark cutoff line and a shoulder, and wherein the lamp, in particular a lamp as described above, is positioned horizontally in the reflector, and wherein the reflective interior surface comprises at least one beam-shaping region realized to deflect a portion of the light emitted from the lamp between 7.5° and 15° below a horizontal plane, at a specific region within the beam profile.
Abstract:
A high pressure gas discharge lamp has electrodes that project into a discharge space surrounded by a discharge wall. The discharge space has a filling of rare gas and metal halides. The metal halide composition comprises halides of sodium and scandium with a mass ratio of halides of Sodium and Scandium of 0.9-1.5. In order to provide a lamp that can be easily manufactured and is well suited for operation at reduced power, the discharge vessel wall is of externally and internally cylindrical shape. The lamp may be manufactured by providing a cylindrical tube of quartz material, heating the tube at two distant portions and forming grooves there, inserting two electrodes into the tube and heating and pinching the tube at both ends to seal the discharge space. Manufacture is carried out without a bulb forming step such that the discharge space remains in externally and internally cylindrical shape.
Abstract:
The invention describes a mercury-free high-intensity gas-discharge lamp (1) comprising a discharge vessel (5) enclosing a filling in a discharge chamber (2) and comprising a pair of electrodes (3, 3′, 4, 4′) extending into the discharge chamber (2), for which lamp (1) the electrodes (3, 3′, 4, 4′) are free of thorium, and the filling includes a halide composition comprising at least 6 wt % thorium iodide.
Abstract:
A high pressure gas discharge lamp 10 is described with a discharge vessel 20. Electrodes 24 project into a discharge space 22 of a volume of 12-20 mm3. The discharge space has a filling of rare gas and a metal halide composition which is free of mercury. The metal halide composition comprises at least halides of Sodium and Scandium with a mass ratio of halides of Sodium and Scandium of 0.9-1.5. The lamp 10 further comprises an outer enclosure 18 provided around the discharge vessel 20, which is sealed and filled with a gas at a pressure below 1 bar. The lamp 10 has an efficiency equal to or greater than 90 lm/W in a steady state operation at an electrical power of 25 W.