| 摘要 |
PURPOSE:To allow low-illumination adjustment by turning an incandescent lamp on and turning a luminescent lamp off when the lamp current value becomes the preset current value or lower and turn the incandescent lamp off and turning the luminescent lamp on when the incandescent lamp current value becomes the preset current value or higher. CONSTITUTION:A discharge lamp has a incandescent lamp and is switched to an incandescent lamp by the first switching means 14 when the lamp current detected by a lamp current detecting means 12 becomes the preset current value or lower, and it is switched to a luminescent lamp by the second switching means 15 when the incandescent lamp current detected by an incandescent lamp current detecting means 13 becomes the preset current value or higher. Therefore, at low illumination the luminescent lamp is turned off and the incandescent lamp is turn on. Accordingly, low-illumination adjustment is allowed. |
