(FR2687781-A1)      The unit for monitoring the efficiency of airport runway and taxi-way lights consists of a towed frame (20) with a coder wheel (33) for measuring the distance between two lights, and a light beam detector.    The frame also carries a nacelle and a closed housing (10) contg. a photo-electric sensor. The housing has a translucent front face to ensure an omnidirectional diffusion of the light from a beam being measured, and at least one other face with a high diffusing reflection capacity to ensure a homogeneous reflection and diffusion of the light towards the sensor. The sensitive portion of the sensor is located at the level of the front face but is directed towards the reflective face.    In addition to its photo-electric cell, the sensor has a photodiode and a phototransistor or photoresistor, while the translucent front face of the housing (10) has a flat panel made from methacrylate, opal polyethylene or polycarbonate.    ADVANTAGE -   The unit is simple, permitting continuous measurement of light beams.    (US5315106-A)      Appts. for in-situ evaluation of the light flux of intense narrow light beams, partic. runway beacon lights, comprises a towed chassis with an encoding wheel determining distance travelled between two lights, and a pod to hold a closed box contg. a photoelectric sensor.    Box has a translucent front face (1) diffusing the light from a beam omni-directionally inside the box, and at least one other face (15) with high diffusing reflection power which directs the light uniformly to the sensor (6) which is located adjacent to the front face but faces the reflecting face. The front face is pref. a flat panel of methacrylate resin, opalescent polyethylene or polycarbonate.    ADVANTAGE -   Permits rapid and continuous measurements directly providing data proportional to the light flux, using simple appts. and without dismantling and removing the lights.    (EP558405-B1)      The unit for monitoring the efficiency of airport runway and taxi-way lights consists of a towed frame (20) with a coder wheel (33) for measuring the distance between two lights, and a light beam detector.    The frame also carries a nacelle and a closed housing (10) containing a photo-electric sensor. The housing has a translucent front face to ensure an omnidirectional diffusion of the light from a beam being measured, and at least one other face with a high diffusing reflection capacity to ensure a homogeneous reflection and diffusion of the light towards the sensor. The sensitive portion of the sensor is located at the level of the front face but is directed towards the reflective face.    In addition to its photo-electric cell, the sensor has a photodiode and a phototransistor or photoresistor, while the translucent front face of the housing (10) has a flat panel made from methacrylate, opal polyethylene or polycarbonate.    ADVANTAGE -   The unit is simple, permitting continuous measurement of light beams.