| 摘要 |
<p>Disclosed is a high-pressure discharge lamp lighting device intended to increase the life of a discharge lamp by optimally maintaining the electrode projection shape and tip shape over the long term. In a lighting device that lights a high-pressure discharge lamp having mercury enclosed, and also having a pair of electrodes disposed facing each other inside a discharge vessel made of quartz glass, alternating current is supplied so as to alternately produce an alternating current of a frequency (basic frequency) - selected from a range between 60-1000Hz - at times of steady lighting, and a half-cycle, low frequency, which is a lower frequency than the basic frequency. In addition, alternating current is supplied in a manner such that one polar wave profile of the low frequency appears twice or more in succession. Alternating current may be supplied so as to alternately produce the aforementioned steady lighting alternating current and the low frequency, which is a frequency selected from a range between 5-200Hz and which is a lower frequency than the basic frequency. Also, the period during which the basic frequency is supplied can be controlled so as to gradually increase and/or decrease with each specified time.</p> |
