R5906112 /09 UDX series201.5 HD for fully enclosed projection systemsHDHazard Distance (HD) is the distance measured from the projection lens at which the intensity or theenergy per surface unit becomes lower than the applicable exposure limit on the cornea or on theskin. The light beam is considered (to be) unsafe for exposure if the distance from a person to thelight source is less than the HD.Restriction Zone (RZ) based on the HDThe projector is also suitable for rear projection applications; projecting a beam onto a defuse coatedprojection screen. As displayed in Image 1-4 two areas should be considered: the restricted enclosedprojection area (RA) and the observation area (TH).RA THswPDHD DIFFUSEswRZsw swPRHDREFLECTIONRESTRICTEDAREARESTRICTEDAREAImage 1-4RA Restricted Access location (enclosed projectionarea).PR Projector.TH Theater (observation area).RZ Restriction Zone.PD Projection Distance.SWSeparation Width. Must be minimum 1 meter.For this type of setup 3 different HD shall be considered:• HD as discussed in “High Brightness precautions: Hazard Distance (HD)”, page 17, relevant for intrabeamexposure.• HDreflection : the distance that has to be kept restrictive related to the reflected light from the rear projectionscreen.• HDdiffuse : the relevant distance to be considered while observing the diffuse surface of the rear projectionscreen.As described in “High Brightness precautions: Hazard Distance (HD)”, page 17, it is mandatory to create arestricted zone within the beam areas closer than any HD. In the enclosed projection area the combination oftwo restricted zones are relevant: The restricted zone of the projected beam toward the screen; taking intoaccount 1 meter Separation Width (SW) from the beam onward. Combined with the restricted zone related tothe rear reflection from the screen (HDreflection); also taking into account a 1 meter lateral separation.The HDreflection distance equals 25% of the difference between the determined HD distance and the projectiondistance to the rear projection screen. To determine the HD distance for the used lens and projector model seechapter “HD in function of modifying optics”, page 21.HDreflection = 25% (HD – PD)The light emitted from the screen within the observation shall never exceed the RG2 exposure limit,determined at 10 cm. The HDdiffuse can be neglected if the measured light at the screen surface is below 5000cd/m² or 15000 LUX.Safety
