Journal of the Society of Motion Picture Engineers (1930-1949)

Record Details:

Something wrong or inaccurate about this page? Let us Know!

Thanks for helping us continually improve the quality of the Lantern search engine for all of our users! We have millions of scanned pages, so user reports are incredibly helpful for us to identify places where we can improve and update the metadata.

Please describe the issue below, and click "Submit" to send your comments to our team! If you'd prefer, you can also send us an email to mhdl@commarts.wisc.edu with your comments.




We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.

Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.

July, 1939] A TELEVISION FILM SCANNER 21 optical axes displaced, or parallel blocks of glass inclined toward the main optical axis at suitable angles. The field-frequency of 60 frames per second conforms to the U. S. television standards and requires that five images be produced and displaced within Vi2 of a second. A rotating shutter with five concentric slots, each slot covering an angle of 72 degrees and a disk rotating at a synchronous speed of 720 rpm permits the passage of light for only one image at a time. Fig. 2 is the schematic layout of a scanner employing five mirrors for splitting up the beam, while Fig. 3 shows a similar layout Y FIG. 3. Schematic layout using five lenses: (a) arrangement of optical parts; (b) virtual images and displacement of real images by the -five dissecting lenses. using five lenses. The total amount of light available at the multiplier photocell when splitting up the original image is l/& of that obtainable with the first method where the optical or electron image itself is deflected and no image-splitting takes place. However, there is sufficient light available for both methods when a suitable incandescent lamp is used. Fig. 4 is a photograph of the latest film scanner using a dissector tube. In this arrangement a 1500-watt projection lamp is used as light-source which illuminates the gate evenly. In Fig. 3 the mirror M and the condenser lens system L produce an intermediate image of the filament in the plane x-x. This image is projected through the