Patent ID: 8292980
Filing Date: 2012-10-23
Classification: B03C,G03B,H04N

Abstract:
1. A projection type image display apparatus comprising a housing having at least an air intake and an exhaust, a blower unit for intaking or exhausting air, a light source unit, an image forming unit, a projection optical system, a power supply unit, and a dust capture device, the dust capture device comprising: first and second winding shafts disposed at a predetermined spacing; a rolled filter stretched between the first and the second winding shafts, unused part of the filter being wound around the second winding shaft; an opening provided between the first and second winding shafts so as to allow an air to flow through the filter; a brush provided at a predetermined position between the first and the second winding shafts so as to come into contact with a surface of the filter; a feeding mechanism for driving the first and the second winding shafts to take up or rewind the filter using the first and the second winding shafts; and a feeding control unit for controlling the feeding mechanism, wherein when a set condition is detected, the feeding control unit activates a renewing operation for feeding unused part of the filter from the second winding shaft to the opening, in which the feeding control unit controls the feeding mechanism such that once the filter is taken up by the first winding shaft by a take-up amount La, then the filter is rewound by the second winding shaft by a rewind amount Lb, and La and Lb satisfy a relationship La≧Lb, and the feeding control unit repeats the renewing operation every time the set condition is detected.