▎ 摘　　要

NOVELTY - The projector has filter for filtering foreign substances in air introduced through air inlet, and a filter sheet detachable from a slot. A cooling fan is utilized for cooling parts by generating wind through the air passing through the filter. A wind speed meter measures actual wind speed at the inlet. A control unit includes a storage part storing reference wind speed of the cooling fan. An alarm generator generates an alarm according to generation and size of a comparison value. The filter sheet includes 1 to 10 parts by weight of a filtering functional body including graphene oxide, cloth, non-woven fabric and an elastic body having multiple holes. USE - Beam projector for generating alarm for cleaning filter by detecting foreign substances remaining in filter at cooling wind speed. ADVANTAGE - The projector generates the alarm for cleaning the filter by identifying the foreign substances remaining in the filter with the cooling wind speed of the cooling fan so as to determine whether the foreign matter remains in a filter due to high or low wind speed, so that quick filter replacement and cooling efficiency can be ensured. The projector measures the wind speed and temperature change of the air introduced into the filter through the heating unit so that intuition of wind speed measurement can be provided. DESCRIPTION OF DRAWING(S) - The drawing shows a block diagram of beam projector for generating alarm for cleaning filter by detecting foreign substances remaining in filter at cooling wind speed. Cooling fan (20) Air inlet (30) Control unit (100) Storage unit (110) Determination unit (120)