A measurement method for three-dimensional inner and outer surface profiles and spatial shell uniformity of laser fusion capsule

We propose a novel laser differential confocal measurement method with high spatial resolution for the simultaneous measurement of 3D inner and outer surface profiles and spatial shell uniformity of capsules. The zero-crossing point of characteristic curve of a laser differential confocal sensor (LDCS) exactly corresponds to the focal point; therefore, the proposed method performs high-precision and fast fixed-focus measurements on the vertexes of the surfaces of the capsule along its radial direction using the sensor. Then through the precision rotation measurement of the circumference trace and multi-directional meridian contour measurement of the capsule around the horizontal axis, the simultaneous high-precision measurement of 3D inner and outer surface profiles and spatial shell uniformity of the capsule can be achieved. To the best of our knowledge, the proposed method is the first to achieve high-precision and non-destructive measurement of 3D inner and outer surface profiles and spatial shell uniformity of the capsule simultaneously, and it provides a novel technical approach for achieving high-precision and non-destructive measurement of geometric parameters of ICF capsules.