Automated optical inspection (AOI) is a key element in the inspection of PCB boards. Each year the measured parameters on the boards get smaller.The most popular optical inspection tools in the production line are the Telecentric Lens known mainly for their large working distance and the long depth of field. However, these two main features pose a limit to the higher resolutions required.
Omek Optics has introduced the PCB Inspection Microscope (Mic401E.80) to bridge the gap between conventional digital microscopy and the current widely used telecentric lenses equipped with digital sensors. The Mic401E.80 tube is mated to long working distance (WD) telecentric objectives to reach overall magnifications between x8 and x0.8. Figure 1 demonstrates how the Mic401E.80 provides better resolutions at magnifications overlapping those provided by standard telecentric lens. The graph also illustrates how the Mic401E.80 can reach higher magnifications at superior resolutions.
Figure 1: Extending resolutions in PCB inspection using Omek Mic401E.80 tube.
Additional advantages of the PCB Inspection Microscope:
Omek Optics, a leading manufacturer of OEM Industrial microscopes has upgraded the 300 series Microscopes by adding a Polarizer / Analyzer Option for all products. The use of cross polarizers acheives maximum resolution and contrast by elliminating undesired stray reflections when using bright field illumination. A polarizer is positioned in the Illumination path of the standard bright field illuminating the object. The reflected light is composed of both diffuse and specular reflections. The latter are filtered by the second polarizer (the analyser) which is rotated 90 degrees relative to the original polarizer. The Polarizer housing allows full 360 Degrees of Rotation. Omek Polarizing Microscopes in combination with Bright Field Kohler Illumination offer superb image quality in applications such as SWIR sub-surface Silicon Inspection, MEMs inspection and Stress in Silicon Substrates.