Patent ID: 7330214

Claim:
A diaphragm apparatus of a lens for a CCTV camera comprising: a diaphragm blade which opens and closes a stop aperture of said diaphragm apparatus; and an ND filter which is attached to said diaphragm blade, said ND filter having a spectral transmittance such that the transmittance of infrared radiation through said ND filter at the infrared spectrum is equal to or less than the transmittance of visible light through said ND filter at any range of the visible light spectrum by an amount such that the transmittance of the visible light is the same over the entirety of the visible light spectrum and the transmittance of the infrared light is the same over substantially the entirety of the infrared light spectrum; wherein said ND filter covers said stop aperture when said diaphragm blade is moved to open said aperture.