Device for operation of a high pressure discharge lamp
AssigneeUshiodenki Kabushiki Kaisha
InventorsYoshikazu Suzuki, Katumi Sugaya, Tomoyoshi Arimoto
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Abstract
To positionally stabilize the arc spot and to prevent the formation of so-called flicker, a super-high pressure discharge lamp which is filled with greater than or equal to 0.20 mg/mm3 of mercury has a feed device which supplies an alternating current with a steady-state operating frequency of from 60 Hz to 1000 Hz and a low frequency of from 5 Hz to 50 Hz. The feed device inserts the alternating current with the low frequency into the alternating current with the steady-state operating frequency with a time interval which has a length equal to at least one half period and at most to five periods, and the time interval being in the range of from 0.1 sec to 120 sec.
Claims6
Device for operation of a high pressure discharge lamp, comprising:
- a super-high pressure discharge lamp having a silica glass discharge vessel in which a pair of opposed electrodes, with projections which have been formed on the their tips, are disposed with a distance between them of at most 2.0 mm, and the vessel being filled with at least 0.20 mg/mm3 of mercury and with a halogen in an amount of 10−6 μmol/mm3 to 10−2 μmol/mm3;
- and
- a feed device which supplies an alternating current to the discharge vessel,
- wherein the feed device is adapted to supply alternating current to the super-high pressure discharge lamp with both a steady-state operating frequency and a low frequency, the steady-state operating frequency being selected from the range from 60 Hz to 1000 Hz and the low frequency being lower than the steady-state operating frequency and being in the range of from 5 Hz to 50 Hz, and wherein the feed device is adapted to insert the alternating current with the low frequency into the alternating current with the steady-state operating frequency with a time interval which has a length of equal to at least one half period and at most equal to five periods, said time interval being in the range of from 0.1 sec to 120 sec.
Dependencies are inferred from the claim text.