Product Code: ILSC2007_1508

Assessment of AEL for Scanning Lasers: Relaxed Eye
Authors:
Bryan Tozer, Lasermet LTD; Dorset Great Britain
Presented at ILSC 2007

The purpose of this paper is to propose a new, more acceptable way of assessing the thermal retinal hazard arising from exposure to a scanning laser beam when the exposed eye is relaxed and therefore sees an image moving across the retina. For the situation where the eye fixes upon the scanning mirror, the image is stationary on the retina and therefore can be treated in the normal way prescribed in IEC 60825-1 for stationary beams; it is not addressed in this paper. This paper uses the existing model as used in assessing AELs and MPEs in 60825-1, including the underlying philosophy of the extended source, but modified to take account of the time taken for the retinal image of the beam to scan 1.5mrad across the retina. However, the recommended measurement procedure for this assessment of scanning lasers is markedly different from that laid down in IEC 60825-1.