Technique Offers Real-Time 3-D Microscopy for Materials

Kathleen G. Tatterson

JENA, Germany -- German microscope manufacturer Carl Zeiss Jena GmbH has developed a technique that it says provides three-dimensional, real-time microscopic images with the high resolution and sharp contrast of conventional light microscopy.
The system offers three-dimensional capabilities to most of Zeiss' microscopes. According to the company, instruments enhanced with the liquid crystal display (LCD) shutter system would be beneficial to the semiconductor industry, where manufacturers could detect dirt and contaminants in wafer layers; in materials microscopy, making visualization of opaque surface topography possible; and in biotechnology, especially for manipulating cells.
Another advantage to using this technique is its improved resolution, caused by the inclination of the illuminating axis. Ingolf Seidler, product manager of Zeiss' microscope division, said that a microscope employing the new system would have 15 percent better resolution and an image depth of focus up to three times better.
The technique also offers three-dimensional imaging in real time. "The image is not captured through a video system, sectioned into slices and reassembled into 3-D, as people tend to think when they hear '3-D imaging,' " he said.
The system makes the eye see an image in 3-D by introducing a "split-type" shutter into the microscope's light path. The LCD shutter system consists of a circular disc that is alternately lifted on each side so that half the disc is opaque and the other is transparent. The switching takes place at a speed of 100 Hz/s, and when the brain sees 100 separate images -- 50 from each side -- it cannot distinguish between them and sees only one three-dimensional image.
"The brain is accustomed to working in three dimensions," said Seidler. "Generally, two-dimensional [microscopic] images are actually 3-D because they have some limited depth."
Zeiss launched the new system at the Quality Expo in Rosemont, Ill., in April and demonstrated the technique at the 3D Microscopy Symposium in Vancouver, British Columbia, Canada, in June.