Phototools, Part C


Reading time ( words)

The objective of this column is to familiarize the reader with silver halide phototools.

Halides are salts that contain an ion from the group of elements called halogens, Group 7 of the periodic table. The word halogen is derived from the Greek words for “salt” and “to generate.” The halides found in silver halide phototools are typically chloride or bromide and sensitive to UV radiation. When exposed to UV radiation, nuclei of metallic silver are formed and can be grown into larger silver crystals by treating them with a reducing chemical.

Silver halide films are much more versatile than diazo films and can be used in a broader range of applications than the diazo materials. High-speed films are typically 100,000 times faster than diazo films, allowing them to be used in low light and high-speed recording applications such as photo plotters, cameras, and step-and-repeat machines.

Figure 1 shows silver halide crystals. The silver halide crystals used in silver halide films are composed of a combination of silver bromide, silver chloride, and silver iodide. They are typically cubic or triangular in shape with edges approximately 200 to 300 nm long. A crystal of this size will contain about 10 million atoms. To each crystal are added a few atoms of a sensitizing material, such as gold or sulfur, to form a sensitivity center.

Read the full column here.


Editor's Note: This column originally appeared in the February 2014 issue of The PCB Magazine.

Share

Print


Suggested Items

Market Drivers and ESI’s Ongoing Developments

11/28/2019 | Real Time with...productronica
During productronica 2019, the I-Connect007 Editorial Team met with some of the industry's top executives, managers, and engineers.

Happy Holden Previews His AltiumLive Frankfurt Keynote

10/17/2019 | Andy Shaughnessy, I-Connect007
I recently sat down for an interview with Happy Holden, who is slated to give a keynote speech at this year’s AltiumLive event in Frankfurt, Germany. Happy gives a preview of his presentation, which is focused on smart factories and automation, and why artificial intelligence might improve PCB design and fabrication in the future.

New High-speed 3D Surface Imaging Technology in Electronics Manufacturing Applications

10/09/2019 | Juha Saily, Focalspec Inc.
Line confocal sensors—and scanners based on them—are used in the imaging of surfaces, transparent materials, and multi-layered structures in various metrology and inspection applications on discrete parts, assemblies, webs, and other continuous products. Line confocal sensors operate at high speed and can be used to scan fast-moving surfaces in real-time as well as stationary product samples in the laboratory.



Copyright © 2019 I-Connect007. All rights reserved.