| 摘要 |
PURPOSE:To make brightness adjustment, which is manually made when a filter is attached and detached, unnecessary and to facilitate an adjusting operation by providing the attaching and detaching part of the optical filter with a switch means for adjusting brightness and adjusting brightness corresponding to the attachment and detachment of the filter. CONSTITUTION:When the filter 2 is fitted on a loading part 3 through arms 2a and 2a, the loading part serving also as a switch is turned on to raise a voltage VD, and the input voltage of a brightness adjusting mechanism 4 is increased. Then a grid voltage applied to a CRT 5 is raised to increase the brightness, which is automatically set to the brightness corresponding to the filter 2. If the filter 2 is detached, the loading part acting also as a switch is turned off to drop the voltage VD, and the brightness is automatically returned to its normal brightness in the state where the filter is not loaded. Thus the display device can be automatically adjusted to the optimum brightness corresponding to the attachement and detachment of the filter in such a way, and it is unnecessary that an operator has to operate an adjusting switch whenever the filter is attached and detached, which occurs in a conventional device. |
