Photoplotter: Difference between revisions
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A '''photoplotter''' is a specialized electro-opto-mechanical machine that exposes a latent image on a medium, usually high-contrast monochromatic ([[black-and-white]]) [[photographic film]], using a light source under [[computer]] control.<ref name="Clark2012">{{cite book|author=Raymond H. Clark|title=Handbook of Printed Circuit Manufacturing|url=https://books.google.com/books?id=hCAyBwAAQBAJ&pg=PA17|date=6 December 2012|publisher=Springer Science & Business Media|isbn=978-94-011-7012-3|pages=17–}}</ref> Once the film has been exposed, it must be [[photographic processing|processed]] before it is ready for use. |
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{{unreferenced|date=October 2012}} |
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A '''photoplotter''' is an electro-mechanical-optical machine that exposes a latent image on a media, usually high-contrast monochromatic ([[black-and-white]]) [[photographic film]], using a light source under [[computer]] control. Once the exposing step is complete, the media is processed in a film processor using a [[Photographic developer|developer]] solution, along with [[photographic fixer|fixing]], washing, and drying. |
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Photoplotters are used primarily for industrial production of [[printed circuit board]]s (PCB) and [[integrated circuit]] (IC) packaging. In the PCB industry, photoplotting is the first step of making [[photolithography]] masks for printed circuit boards. These masks are called ''photoplots'' and are limited in resolution by the technology in use; in 1998 photoplots with resolvable details of 2.5 [[micrometre|µm]] or more were possible.<ref>{{cite book|title=Electronic Products|url=https://books.google.com/books?id=v8YpAQAAMAAJ|year=1989|publisher=United Technical Publications}}</ref> Integrated circuits are made in a similar fashion utilizing ''[[photomask]]s'' with sub-micrometer feature sizes; photomasks are traditionally made by photoreducing photoplotter output.<ref>{{cite book|title=Electronic Packaging and Production|url=https://books.google.com/books?id=lMMpAQAAMAAJ|year=1987|publisher=Cahners Pub.}}</ref> |
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Other application of photoplotters include chemical milling and specialized graphic arts.<ref name="Sharpe1994">{{cite book|author=Carill Sharpe|title=Kempe's Engineers Year-book|url=https://books.google.com/books?id=y3NRAAAAMAAJ|year=1994|publisher=Morgan Bros.}}</ref> |
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==History== |
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| ⚫ | Modern photoplotters are generally [[raster graphics|raster-scan]] devices that use a [[laser]] beam focused to one or more spots, |
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The first photoplotter was introduced by [[Gerber Scientific|Gerber Scientific, Inc.]] in the 1960s.<ref name="Gerber2015">{{cite book|author=David J. Gerber|title=The Inventor's Dilemma: The Remarkable Life of H. Joseph Gerber|url=https://books.google.com/books?id=8YKqCgAAQBAJ&pg=PA167|year=2015|publisher=Yale University Press|isbn=978-0-300-12350-0|pages=167–}}</ref><ref name="Schroeder1998">{{cite book|author=Chris Schroeder|title=Printed Circuit Board Design Using AutoCAD|url=https://books.google.com/books?id=t0fPJOGYaasC&pg=PA17|year=1998|publisher=Newnes|isbn=978-0-7506-9834-4}}</ref>{{rp|17-}} The company's file standard, the [[Gerber format]] for PCB files, eventually became an industry standard for describing the printed circuit board images such as the copper layers, solder mask and legend.<ref name="Sanz1988">{{cite book|author=Jorge L.C. Sanz|title=Advances in Machine Vision|url=https://books.google.com/books?id=K3Wz6l2tFU0C&pg=PA196|date=1 December 1988|publisher=Springer Science & Business Media|isbn=978-0-387-96822-3|pages=196–}}</ref><ref name="Khandpur2005">{{cite book|author=R. S. Khandpur|title=Printed Circuit Boards: Design, Fabrication, Assembly and Testing|url=https://books.google.com/books?id=VY8iBAAAQBAJ&pg=PA244|year=2005|publisher=Tata McGraw-Hill Education|isbn=978-0-07-058814-1}}</ref>{{rp|244-}} |
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| ⚫ | Early machines used a [[xenon flash lamp]], and projected an image mounted in a rotating ''aperture wheel'' onto the photosensitive surface of the film or glass plate.<ref name="Mitzner2009">{{cite book|author=Kraig Mitzner|title=Complete PCB Design Using OrCAD Capture and PCB Editor|url=https://books.google.com/books?id=z7RCh8bK6_8C&pg=PA54|date=28 May 2009|publisher=Newnes|isbn=978-0-08-094354-1}}</ref>{{rp|54}} The imaging head assembly traversed over the surface of the media without touching it to produce ''draws'' and ''flashes''. Draws are vectors or arcs created by continuous illumination as the imaging head moves over the photosensitive surface. A flash creates a single simple graphic in a location by shining light through an aperture of the appropriate shape at a fixed location.<ref name="Khandpur2005"/>{{rp|234}} |
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Photoplotters are closely related to [[imagesetter]]s. Photoplotters differ from their imagesetting counterparts in the type of controller used to produce the image, and in the resolution and absolute accuracy of the image, with photoplotters meeting much more stringent specifications than imagesetters. |
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| ⚫ | The most recent development related to photoplotting is |
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| ⚫ | The most recent development related to photoplotting is laser direct imaging (LDI) which utilizes a high-power laser or xenon lamp to directly expose photoresist on a coated substrate instead of exposing photographic film. This eliminates the handling of photographic film.<ref name="Mitzner2009"/>{{rp|6-}} |
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== Typical manufacturers == |
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* [[Gerber Scientific]] |
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* [[Orbotech]] |
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* [[Ucamco]] |
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Manufacturers of photoplotters include Gerber Scientific, [[Orbotech]] and [[Ucamco]]. |
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== See also == |
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*[[Printed Circuit Board]] (PCB) |
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*[[Gerber Format]] (RS-274X) |
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==References== |
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{{reflist}} |
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[[Category:Electronics manufacturing]] |
[[Category:Electronics manufacturing]] |
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Revision as of 19:05, 20 January 2022
A photoplotter is a specialized electro-opto-mechanical machine that exposes a latent image on a medium, usually high-contrast monochromatic (black-and-white) photographic film, using a light source under computer control.[1] Once the film has been exposed, it must be processed before it is ready for use.
Photoplotters are used primarily for industrial production of printed circuit boards (PCB) and integrated circuit (IC) packaging. In the PCB industry, photoplotting is the first step of making photolithography masks for printed circuit boards. These masks are called photoplots and are limited in resolution by the technology in use; in 1998 photoplots with resolvable details of 2.5 µm or more were possible.[2] Integrated circuits are made in a similar fashion utilizing photomasks with sub-micrometer feature sizes; photomasks are traditionally made by photoreducing photoplotter output.[3]
Other application of photoplotters include chemical milling and specialized graphic arts.[4]
History
The first photoplotter was introduced by Gerber Scientific, Inc. in the 1960s.[5][6]: 17- The company's file standard, the Gerber format for PCB files, eventually became an industry standard for describing the printed circuit board images such as the copper layers, solder mask and legend.[7][8]: 244-
Early machines used a xenon flash lamp, and projected an image mounted in a rotating aperture wheel onto the photosensitive surface of the film or glass plate.[9]: 54 The imaging head assembly traversed over the surface of the media without touching it to produce draws and flashes. Draws are vectors or arcs created by continuous illumination as the imaging head moves over the photosensitive surface. A flash creates a single simple graphic in a location by shining light through an aperture of the appropriate shape at a fixed location.[8]: 234
Modern photoplotters are generally raster-scan devices that use a laser beam focused to one or more spots, modulated at multi-megahertz rates to form the image.[6]: 283-
The most recent development related to photoplotting is laser direct imaging (LDI) which utilizes a high-power laser or xenon lamp to directly expose photoresist on a coated substrate instead of exposing photographic film. This eliminates the handling of photographic film.[9]: 6-
The input of photoplotters is a vector graphics file, typically in Gerber format.[6]: 235-
Manufacturers of photoplotters include Gerber Scientific, Orbotech and Ucamco.
References
- ^ Raymond H. Clark (6 December 2012). Handbook of Printed Circuit Manufacturing. Springer Science & Business Media. pp. 17–. ISBN 978-94-011-7012-3.
- ^ Electronic Products. United Technical Publications. 1989.
- ^ Electronic Packaging and Production. Cahners Pub. 1987.
- ^ Carill Sharpe (1994). Kempe's Engineers Year-book. Morgan Bros.
- ^ David J. Gerber (2015). The Inventor's Dilemma: The Remarkable Life of H. Joseph Gerber. Yale University Press. pp. 167–. ISBN 978-0-300-12350-0.
- ^ a b c Chris Schroeder (1998). Printed Circuit Board Design Using AutoCAD. Newnes. ISBN 978-0-7506-9834-4.
- ^ Jorge L.C. Sanz (1 December 1988). Advances in Machine Vision. Springer Science & Business Media. pp. 196–. ISBN 978-0-387-96822-3.
- ^ a b R. S. Khandpur (2005). Printed Circuit Boards: Design, Fabrication, Assembly and Testing. Tata McGraw-Hill Education. ISBN 978-0-07-058814-1.
- ^ a b Kraig Mitzner (28 May 2009). Complete PCB Design Using OrCAD Capture and PCB Editor. Newnes. ISBN 978-0-08-094354-1.
External links
- Ronald B. Webster, Variable Aperture Photoexposure Device, 15 September 1970, 3 October 1972. Gerber variable shutter patent.