Smartphone Camera Height Measurement
Gauge height dimensions for complex, transparent camera assemblies
The camera is a key differentiating feature in the competitive smartphone market. The exacting image quality requirements of smartphone cameras mean that inspection has to be extremely precise. Even small variations in height in any of the various optical layers of the camera can cause unacceptable image degradation. All of the optical parts were inspected separately prior to assembly, but that will be useless if their installation is misaligned.
The inspection process requires many different measurements and multiple profile points with narrow tolerances. Only a telecentric lens, which collimates the light to minimize geometrical distortion and perspective effects, can ensure the necessary degree of measurement accuracy.
The wide telecentric lens within Cognex 3D laser displacement sensors captures 2,000 separate points within a single 32 mm laser line profile. By combining all of the profiles within its field of view (FOV) it creates a highly accurate 3D inspection. Combined with high dynamic range (HDR) technology, it adjusts the contrast so that bright and reflective features between the optical layers creates less noise in the inspection image. This allows the laser displacement sensor to determine the alignment of the optical layers more accurately and confirm they are at the proper height.
In addition to height, sometimes manufacturers need to find defects such as particles, hairs, or dust on the lens. The overall solution might also require a 2D vision system with integrated lighting and deep learning capabilities to detect these defects.