The flying-spot microscope

A cathode-ray tube providing a television raster of high brilliance and short time-constant is placed in front of the eyepiece of a microscope. The objective produces a minute spot of light that scans the preparation under examination. The amount of light transmitted is determined by the density of the specimen, and the transmitted light is picked up by a multiplier photocell, the output of which is used to modulate a display cathode-ray tube, the raster of which is locked to the scanning raster. The output of the photo-multiplier is also fed via amplitude and time-discriminating circuits to a high-speed counter. Pictures superior to those of a normal optical microscope in size, brightness, contrast and resolution of low contrast materials are obtained. In the case of a field containing discrete particles such as dust, blood, chemical particles, etc., the particles are automatically counted and sized. Applications to such diverse fields as clinical medicine, computers, nuclear physics, and chemical engineering are described.