Lighting method and apparatus for lighting high-pressure discharge lamp and high-pressure discharge lamp apparatus with reduced load on lighting apparatus
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsMinoru Ozasa, Shunsuke Ono, Masahiro Yamamoto
Life of this patent
Estimating the term…
Abstract
When a detected lamp voltage (Vla) is below a predetermined value (S101: No), an alternating current that is higher in frequency than an alternating current supplied under rated-power operation is supplied (S102) for a predetermined time period (S103). The rated power is 150 W and the higher frequency is 500 Hz.
Claims16
A lighting method for lighting a high-pressure discharge lamp under constant-power control with a lower power than a rated power, the high-pressure discharge lamp having a halogen material sealed therein and a pair of electrodes disposed therein, the lighting method comprising the steps of:
- judging whether a voltage across the pair of electrodes is below a predetermined value;
- and
- supplying, for a predetermined time period, an alternating current that is higher in frequency than an alternating current supplied prior to the judgment, when the voltage is judged to be below the predetermined value.
A lighting method for lighting a high-pressure discharge lamp by supplying an alternating current under constant-power control with a lower power than a rated power, the high-pressure discharge lamp having a halogen material sealed therein and a pair of electrodes disposed therein, wherein
- the alternating current supplied is higher in frequency than an alternating current supplied under rated-power operation.
A lighting apparatus for lighting a high-pressure discharge lamp by supplying an alternating current thereto, the high-pressure discharge lamp having a halogen material sealed therein and a pair of electrodes disposed therein, comprising:
- a voltage detector for detecting a voltage across the pair of electrodes;
- and
- a controller for controlling, when the high-pressure discharge lamp is operated with a lower power than a rated power and when the detected voltage is below a predetermined value, the alternating current so that the alternating current is higher in frequency for a predetermined time period than an alternating current supplied under rated-power operation.
A lighting apparatus for lighting a high-pressure discharge lamp by supplying an alternating current thereto, the high-pressure discharge lamp having a halogen material sealed therein and a pair of electrodes disposed therein, comprising:
- a controller for controlling, when the high-pressure discharge lamp is operated with a lower power than a rated power, the alternating current so that the alternating current supplied is higher in frequency than an alternating current supplied under rated-power operation.
Dependencies are inferred from the claim text.