dawson cd intro

8/3/2019 Dawson CD Intro

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CD: Technology and

Manufacture

Anna Domask

Angelika Franz

Jeremy Lieberman

Alex Tumminelli


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Outline Disc player components

CD DVD

Blu-Rays

Comparison Manufacturing


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Components Laser system

Tracking system

Drive motor

Spins disc 200-500rpm depending ontrack being read

Discs


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Laser System Laser focused on bumps

Beam passes through polycarbonatelayer, reflects off aluminum

Hits opto-electronic sensor: detects

changes in bumps/lands of aluminum Changes to electrical signal to be read


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Refraction Changes in Media

Air n ~= 1; = 780

Polycarbonate n=1.55; = 500

Initial Spot 800 m,

final 1.7 m


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Reflection


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Interference

This allows the data to be transmitted

Transitions - 1

Hills and Valleys - 0


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Laser System


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Captured Pattern Spacing between

pits- carefully

selected. Nulls carefully

situated to fall onthe neighboring pit

tracks Minimizes crosstalk

from neighboring

pits


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Tracking System Moves laser outward on CD

Constant linear speed CD spins slower as laser moves from insideto outside

Data read off disc at constant rate


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Compact Disc Label Acrylic: protect aluminum layer

Aluminum: thin reflecting layer covering

bumps Polycarbonate: optically transparent


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Compact Disc (cont) 783 MB on 4.8 in

diameter disc

track: 0.5 m wide,1.6 m separation

pits: 0.5 m wide,

minimum 0.83mlong, 125 nm high


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The Need for Error Handling


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CD Error Handling Reed-Solomon Error Correction

Stores extra data bits to accommodate errors

Periodic markers allow software to recognize if anerror occurs

Predominately set to handle single bit errors

Data is stored non-sequentially so group errors

(like a blot on the CD) appear as scattered singlebit errors


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CD Error Handling (cont) Companies are adding an extra polymer layer to

protect CD from everyday wear and tear

Resists scratches and scuffs Resists smudges and grime

Resists Dust

Examples of companies producing new layer

Imation: ForceField scratch resistant layer

Maxell: MAXPRO Hardcoat technology

TDK: DURABIS coating technology


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General CD myths Should place CDs data-side down

The term burning CDs comes fromthe burning of plastic to write the CD

CDs were supposed to be 60 minuteslong but Sony insisted they be 74

minutes so that they could hold eventhe slowest version of Beethovens 9thSymphony


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DVD 4.7 GB storage capability

Same layering as CD with added semi-reflective gold layer

Bumps: 320 nm wide, minimum 400 nmlong, 120 nm high

Track spiral from inside to out Can have double-layering of data to

increase data storage


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Blu-Ray Uses shorter wavelength

405 nm wavelengthinstead of 650 nm redlaser

Pits only .15 m

Track pitch .32 mdown from .74

May be possible to layerbeyond 2 layers http://www.blu-raydisc.com/


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Blu-Ray (cont)Advances continue

25 GB disc made with 51% paper

Playstation 3 will use blu-ray technology Blu-ray very heavily supported by Sony

Prototypes are currently being made

Expected release of blue ray products in late

2005 in the format of recordable media Sony has released some recorders in Japan

with a price tag of $3000 which is expected tocome down


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Blu-Ray vs other new formats Primary competition is HD-DVD

Manufactured with same equipment that makes DVDs

Equipment easily compatible with old technology Less storage capability than blu-ray (20 GB or 30 GB with

dual layer)

HD-DVD strongly supported by Toshiba

Blu-ray ahead in the process and strongly backed

Blu-ray products have been featured with both blueand red laser to read DVDs as well as new discs


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Comparison of Formats Laser wave-length

different

Blu-Ray and DVD havemore storage capabilitybecause track pits aresmaller

CD has much older errorcorrection method, sowastes more space


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Manufacturing CDs Five General Methods of CD

Manufacturing

Standard Stamper-Injection Molding

Direct Read and Write Mastering (DRAW)

Direct Metal Mastering (DMM)

Photopolymerization (2P)

Photolithography


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Standard Stamper-Injection

Molding Glass master coated with

photoreactive layer Master electroformed to

create stampers forinjection molding process Discs formed out of

polycarbonate then coatedwith thin reflective metal

layer Coated with acrylicprotective layer, labeled,then placed in jewel boxesfor shipping


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Other Manufacturing Methods DRAW

Similar to Standard Stamper-Injection Molding

Master coated with plasticand uses ion laser tovaporize sections of plastic

DMM

Master created out of metal

Piezoelectric stylus with adiamond tip used to etchsurface of a metal disc


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Other Manufacturing Methods 2P

Modifies injection

molding UV sensitive lacquer

sandwiched betweenmold and thinpolycarbonate

substrate UV light shown

through substrate tocure lacquer


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Bibliography http://electronics.howstuffworks.com/cd.htm

http://electronics.howstuffworks.com/question655.htm

http://electronics.howstuffworks.com/dvd.htm

http://electronics.howstuffworks.com/blu-ray.htm

http://www.osta.org/technology/pdf/cdr_qa.pdf

http://www.gizmodo.com/archives/sonys-paper-bluray-discs-009177.php

http://www.sony.net/SonyInfo/News/Press/200404/04-0415E/

http://www.cddimensions.com/blu-ray/blu-ray.asp

http://stereophile.com/features/374/

http://en.wikipedia.org/wiki/Category:CD


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Bibliography P.2 http://www.ee.washington.edu/conselec/CE/kuhn/cdaudio/95x6.htm

http://web.mit.edu/2.972/www/reports/cd_player/cd_player.html

http://www.everything2.com/index.pl?node=optics

http://www.cdman.com/technical/howdocdswork1.html http://www.laserline.com/mistermedia/faq_compact_discs.htm

http://micro.magnet.fsu.edu/electromag/computers/compactdiscs/cd.html

http://www.manifest-tech.com/media_dvd/hard_coat.htm#Industry%20Plan

http://compact-disc.biography.ms/ http://www.manifest-

tech.com/media_dvd/hard_coat.htm#Industry%20Plan

http://en.wikipedia.org/wiki/Compact_disc

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