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Posted: 14 Sep 2017, 04:27 

I now remember why I don't usually answer the phone anymore. i was expecting a call from our roofing contractor since the shingles got delivered yesterday and I wanted to find out when they planned to begin so I answered the phone (contrary to my inclinations).

The male voice said it was my oldest grandson. (We don't have any children let alone grandchildren.) I pretended I could not hear him (setting up for the punchline) and kept asking him to speak louder. Finally I said - "is this my grandson Fred?". Then he said (real loudly) "This is your grandson Fred" (sharp one he was - pretty amazing feat of cold reading there).

At that point I said - "well Fred, guess what - I don't have any grandchildren". At which point he responded with a really clever "F**k you ". I responded in a similar (although a more creative (IMHO) manner) involving the use of a crowbar. At which point my erstwhile relative hung up.

People gonna screw with me I figure I may as well have some fun with it. :twisted:

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Posted: 05 Oct 2017, 09:03 

When I encounter someone I can't get along well with, like your conversation about the LJR-I,
I usually block these buyers so that they cannot bid or buy my auctions anymore.
There is an option like that somewhere quite hidden in the ebay account settings.
I think your best option now is to send him a shipping label and get the player back.
This guy smells like trouble.

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Posted: 05 Oct 2017, 18:59 

Hi elahrairrah - I've had one dealing with this seller.

Some months ago he listed a rare laserdisc for sale.
I proceeded to purchase it and then he refused to ship it to the UK with the following reply:

Thank you for looking at my site and considering purchase of this rare laserdisc. unfortunately, i had not wished to ship this overseas (outside the U.S.), as it is very expensive, in excellent condition and i am afraid it could suffer damage during shipping. if you were to receive it damaged in any way, you would most likely return, and i would be left refunding cost + shipping both ways. i do not think i want to take the risk.
in addition, just to ship to you i would need to use usps priority at a minimum, which is approximately $60 USD. this seems like a high cost.
if you agree with me, we should probably cancel this transaction.
if you have anyone in the US that i could ship to, who would assume risk of travel and forward to you, i would be willing to do that.



Whilst I was agreeable to paying priority mail I was definitely not agreeable to shipping it to a third party in the US as that would mean I had no comeback if he never shipped it all since I am only covered for the address associated with my paypal account.

So we agreed to cancel the transaction. Definitely someone I would NOT purchase from again.
I got the impression he didn't know how to pack LDs properly so I wasn't prepared to take the risk.

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Posted: 05 Oct 2017, 20:56 



Then he leaves me negative feedback on Ebay: "Item shipped missing parts and arrived broken"

Which like I pointed out isn't true about the missing parts (power cord.) Filed a report against his feedback since I cooperated with him so he can get a refund, but who knows if that will actually be retracted.



If it is of any help the negative feedback does not appear to be showing in the "feedback left for others" bit on his page.

Hope you get this sorted.

Regards


.

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Posted: 11 Oct 2017, 01:18 

Well if its any assurance, when we had the mix up with the DVL players I thought that you did a more then adequate packaging, I can vouch for your packing abilites.

Hope things work out..

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Posted: 11 Oct 2017, 21:42 

I just want to post who this is in case we didn't do this earlier.

Ebay ID: theultimateshoppingcenter

This is a massive situation and he is trying to keep the player from this scam, I know how this one works, someone tried this with me years ago.
The LD market is very small and he shouldn't be pulling this type of thing.

I really wonder if he is on LDDB, if he is he should be removed as this is a massive scam.

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Posted: 05 Nov 2017, 03:00 

This guy is bad news. He bought a muse disc from me and claimed it was damaged (before even playing it) and forced a return (disc was fine as I knew it would be).

He also bought a McIntosh 7020 from me once (I sold very clearly indicating that AC3 was non functional) and put back for sale the next day at double the price without disclosing the AC3 issue....very shady dude.

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Posted: 16 Feb 2018, 05:46 

The earliest released Letterboxed Japan LDs I have in my collection are Halloween II and Terror in the Aisles . Unfortunately, neither of those have a listed release date in the database.

Halloween II being sequentially listed between 2 1986 releases, circa 1986 sounds safe to assume.

https://www.lddb.com/search.php?reference=88C59-614%2A&discard=false&sort=ref

Same analysis on Terror in the Aisles should give us 1985:

https://www.lddb.com/search.php?reference=SF___-506*&discard=false&sort=ref

Julien

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Posted: 12 Mar 2018, 15:12 

http://www.laser-disc.com/wp-content/uploads/2018/02/laser-discs.png

Hi guys,

Shameless self-plug, but hey, it's totally on-topic 8-)

I have recently launched a new web magazine for all things LaserDisc. I'm posting LaserDisc reviews, features and interviews - working on new content every week.

http://www.laser-disc.com

Hope you guys like it. If any of you would like to contribute cool LaserDisc topic or material or general ideas please let me know!

Enjoy!

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Posted: 18 Mar 2018, 22:38 

Good day Gentlemen ie,

Marcham93, Audioboyz1973, Signofzeta, Rein-o, Takeshi666, Elahrairrah, Forper, Laserdisc_fan, Randyv, Tasuke & Je280,

Laserdisc_fan: The Blue Nile - Downtown Lights Love Blue Nile that band produce great musical works (Thank you for sharing.)

Guys I have just read all of your posts, and to be honest my pennies worth is quite redundant However, as a fellow member who appreciates the company here, and as words of thanks for each view point and comments conveyed by all of the above.

Marcham93 Thank you for starting this Subject;
Each person here is an individual who's right it is to freely express, and equally by taking the time (in fact I am at work but I Made the time to read all of your comments.) I used this time wisely as Contractors carrying out their duties meant that I had to stay where I was..... So here I am.

Each one' weather (and from) the initial intro, and there afterward I Genuinely enjoyed and reflected upon and thought of my own experiences with the formats I have: CD / MD / LD / DVD / HD DVD / BLU-RAY & BLU-RAY 4K ........ I love this hobby and all that it brings.

A level of civility here is to be maintained at all times, otherwise this forum will fade in it's appeal to all those who cherish coming here and contributing with each unique angle.

I could convey many things here ''that for all intents and purposes have been covered in my previous posts''

Due to the many hours I work, when coming off shift it takes time to clear ones mind, I haven't watched a laserdisc on my new TV for many months, I need more cables analogue to HDMI converter and other items are in need of purchase and completion........ Available disposable income after bills and so on.

The latest TV's have less Legacy inputs and this poses what can be obstacles....... Laserdisc is a format that I shall never part with, and my aim is to get all of these connections and other connections sorted, however it has been slow.....I invested heavily into the Laserdisc Format and for good reason ''I am so glad I did at the time''

I still have around £1200 worth of laserdiscs to pay for from a trusted seller who reserved and I shall see this through........Hopefully by end of this year 2018.
After this my laserdisc collecting will be 99% complete apart from the odd title here and there.

To be honest it's been a long arduous journey, a downright struggle if I am completely honest....... But Remains the best Format for me personally.

However I only purchase 4K Blu-Ray discs now, unless one of the studios only releases the Blu-Ray version of a title I like.

I have The MATRIX on DVD / (LD Preferred) and HD DVD (Warners rotters Damn it) and so with the announcement that this is coming out on 4K pleases me greatly.

I have been informed that Star Trek Voyager will not be released on Blu-Ray, as The Next Generation re-mastered onto Blu-Ray box sets did not sell as well as hoped
So it looks like I shall purchase the above on DVD, sometimes you go with what is available, it can be disappointing at times but that's the way it is, and we all know that.

Guys as mentioned above I am grateful for reading each of your viewpoints and passion of such.

I enjoy 4K for what it offers and when done right is superb, and when Purchasing from the USA can cost up to £42-50 inclusive of postage & taxes, and if I have the funds to do this then I do so with joy knowing that I have purchased something exclusive for me personally....... It's personal that's all.

I prefer physical media, however there is room for both and shall be looking at the purchase of a media Hard drive for my music needs as I am a member of a numerous specialised online retailers.
There is so much music 24bit studio masters that I have listened to that are superb, but around 20% that I would like to own on CD is not on offer, so download it will need to be.

My Point is this and we can all relate to this I am sure: I want quality in music and Movies and so, if it's available I will go with what is shall purchase the necessary in order to obtain....., It takes time with all of these things as we all know.

The main thing is that we enjoy our purchases and enjoy the experiences that accompany such fruits of our labours.

I for one appreciate: Marcham93 viewpoints of which are Genuinely valid...... What ever your needs are go with it and enjoy, and I look forward to the reading from you on any subject that you may have.

One of the reasons why I like this site ''especially to post on like no other'' is because it's quite a unique experience here......... I like that and hope with all seriousness that you all do to, and if not then that's ok also.

Sincerest Regards to everyone and take good care of yourselves,

Kindest Regards

:wave: :thumbup: :wave: :thumbup:

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Posted: 22 May 2018, 16:47 

Speaking of this OAV, it's getting a BD release from Animeigo. The KS was funded. There should be late backer options for those interested, and it will be on their webstore later.

Their releases of Otaku No Video and Bubblegum Crisis on BD were excellent and I expect the same here.

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 Post subject: Re: Oppo UDP-205 PRE-ORDER
Posted: 26 Jun 2018, 03:02 

Pre-order emails seem to have been sent yesterday:


Reference Quality 4K Ultra HD
Audiophile Blu-ray Disc Player

Thank you for your interest in the OPPO UDP-205 - a limited supply is now available. Drawing from over a decade's worth of experience in advanced image processing technology and high fidelity audio performance, the UDP-205 is the perfect choice for discerning enthusiasts. The UDP-205 provides reference level sound quality through the analog outputs, improves the clock precision of the HDMI audio output, and increases the power of the built-in headphone amplifier.

Click here to learn more about the OPPO UDP-205.

To pre-order the OPPO UDP-205, please use this special link:

(custom link removed)

This link is as unique as you are so please do not share. It will expire at 11:59 PM PT on July 3, 2018. Due to the limited quantity available, the limit is 1 per customer. If you are no longer interested in the OPPO UDP-205 and would like to give up this opportunity, click here.

Note: This product is designated for North American Customers Only .

Limit 1 per customer. Not for resale.

Price: US$ 1,299.00

Options:

1 Year Extended Warranty + 2 Year Standard Warranty for UDP-205 (+US$ 99.00)
Rack Mount Kit for UDP-205 (+US$ 99.00)


Since I already own one and I'm not a North American customer, I can pass my pre-order to someone serious about buying one (don't waste it, they sell on eBay for twice this price!). Contact me by PM.

Julien

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 Post subject: [LD-X1] Review
Posted: 27 Jun 2018, 10:04 

LD-X1 Review

https://image.jimcdn.com/app/cms/image/transf/dimension=320x1024:format=jpg/path/sc418f3b0caa8fc1d/image/idf61dc1b3bb95a13/version/1530085877/image.jpg

It took me one month to get a prefect working LD-X1 and lot of money.
First, I did a bid on Yahoo for a superb version of the player : absolutly
no tears, no scratch. With the original box, remote control, and manual.
And the big, very big thing is the official RF-AC3 mod added by MSB. It
costed me 750 $.
The bad news were that image quality was far from perfect. Lot of artefacts
and waves.
One month after, I decided to call Pioneer to take care of my player. Today,
the King has returned ! it came back in perfect working condition ! It's third
time I use the service of Pioneer. I have to say that the technician I met each
time is really professionnal. We had some discussion about LD players, and
Pioneer great days (longtime ago...). It costed me 200 $ more for reparation.
Problems came from old condensators. He changed it. He also changed all the
grease, and belds. The player should work for years without problems now !

Review : (you can find it also in my site : https://retro-visual.jimdo.com/laserdisc/ld-players/ )

Brand : Pioneer
Release : 1989
Media : Laserdiscs, Single Side
Format : NTSC
Video Output : RCA out x1, BNC x1, S-Video out x2
Audio Output :Stereo out x2, Optical out x1, AC3 out x1 (MSB version)
Size : 457×458×182
Weight : 28kg
Release Price : 3700 $ (400.000 yens)
Today price (used) : 300 - 1000 $

The LD-X1 is maybe the best LD player (not hi-vision) ever created.

it's a very specialized player. It can read only single side. CD are not playable.
But it reads LDs so smoothly ! not any sound from the player, even from a
CAV disc. The tray is strong. All is heavy and construted with super quality
material. The player weight 28kg, at the entire service of reading perfectly discs.
I personnaly prefer the metal rending of the HLD-X0, but I have to say that the
LD-X1 with his black piano rending is really a beauty.

Now the intersting part : picture quality. Yes, Pioneer repaired my player,
and they changed lot of condensators. That is certainly the reason why
the picture is now so good. But I have to say that I never saw that on a
LD player, even on my ex-HLD-X0 (RIP). The picture is so soft, colors so
warm, noise near 0 (except in fushia red, and some blue, like every players).
You can choose a pure signal from the disc by BNC, passing through without
any DNR. If you have a good DNR machine, this is clearly the best option. But
you can also choose to use DNR inside the player. It completly erase any trace
of noise, with a very good render.

The analog audio out deliver a very good sound. But because of the age,
the DAC is limited to 18bits. (But it is sometimes better to have a good
18bits DAC dans a bad 20 bits.) If you have a good DAC, you can connect
the player by optical out.

Conclusion : 10/10

Clearly the best player for me. But it takes time, effort and money to get a
working well machine. For people who start LD, or can't risk too much money,
I recommand a CLD-959 (CLD-97).

pictures :

https://image.jimcdn.com/app/cms/image/transf/dimension=1920x300:format=jpg/path/sc418f3b0caa8fc1d/image/i2fc60e58039b7d1b/version/1530089215/image.jpg

https://image.jimcdn.com/app/cms/image/transf/dimension=1920x300:format=jpg/path/sc418f3b0caa8fc1d/image/ice764fffebb13f36/version/1530089305/image.jpg

https://image.jimcdn.com/app/cms/image/transf/dimension=1920x300:format=jpg/path/sc418f3b0caa8fc1d/image/i3de664a08d5b29ad/version/1530089305/image.jpg

https://image.jimcdn.com/app/cms/image/transf/dimension=1920x300:format=jpg/path/sc418f3b0caa8fc1d/image/i9c8f8cdc7997ff05/version/1530089305/image.jpg

https://image.jimcdn.com/app/cms/image/transf/dimension=1920x300:format=jpg/path/sc418f3b0caa8fc1d/image/i30fab3d982280824/version/1530089305/image.jpg

https://image.jimcdn.com/app/cms/image/transf/dimension=1920x300:format=jpg/path/sc418f3b0caa8fc1d/image/if5f7bfceda9dcbf1/version/1530089305/image.jpg

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 Post subject: Technicolor
Posted: 27 Jul 2018, 07:58 

Quite interesting video:



Julien

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 Post subject: Re: Sony MBD-XBR950
Posted: 14 Aug 2018, 21:43 

The 900 is outputting correct AR combed 480i over S-Video with an amazing picture. Issue with this one is no front panel controls so I can't get into the menu (nothing I program my Harmony with works).

Image

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 Post subject: Re: Sony MBD-XBR950
Posted: 14 Aug 2018, 22:04 

Definitely give DVD recorders a run for their money as a comb filter in front of a DVDO or similar -

Image

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Posted: 14 Dec 2018, 03:07 

Hello everyone,

Our friend accuozo was kind enough to submit a lot of scanned versions of The Videophile (here's a quick tribute here ).

http://magazines.lddb.com/The.Videophile/

Mostly about non-LD matters but the "optical disc" does how up a few times and the discussion about U-matic, VHS and Betamax is already entertaining to read after so many years!

Videophile.jpg

Julien

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Posted: 19 Feb 2019, 21:53 

Great find!

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Posted: 20 Feb 2019, 00:14 

Found a used/retro Video Game shop outside of Trenton NJ that had pretty big stash of used LDs. Dude had a lot I wanted to buy, but the guy was charging way too much for them. Ended up just getting this for $20 . . .

https://www.lddb.com/cover/ld/20301-20400/20322.jpg
I had to buy this twice because the seller on eBay sent me a cracked copy. Luckily I stumbled across this a goodwill in KY a few years. Made the first one an album art though I did throw the disc away.
:thumbup:

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Posted: 18 Mar 2019, 18:22 

Hi all, I'm a translator living in Japan, I mainly do programming stuff so I contacted happycube a little while ago to see if there's any translations I could do for free to help out with LD-decode, and he suggested this article. I finished the part he was most interested in (section 4.2), and will probably do the rest of the article sometime soon. Hope you also find it interesting!


------------
http://sts.kahaku.go.jp/diversity/document/system/pdf/085.pdf

"Historical Development of Laser Disc (LD) Technology with Respect to Efforts to Hasten Its Technological Development and Practical Application" by Sumitaka Matsumura

4.2 Element technology in disc production
Section 4.1 noted the basic workflow for the LD disc manufacturing process, but there were a number of element technologies that caused the disc performance or quality to vary in actual production. The following talks about the optimum pit shape, reduction in micro-defects, and reliability (life expectancy) as examples of typical element technologies.

4.2.1 Optimum pit shapes
The most important parameter that caused LD disc performance to vary was pit shapes, particularly in audio/video quality performance. Optimum pit shapes were investigated from a variety of angles for disc production.

(1) Theory and reality
In theory, the ideal pit shape is a "rectangular" type as shown in Figure 4.17 (a). In such cases, when the playback laser wavelength is λ (lambda) and the disc surface refractive index is n, the optimum pit length becomesλ/4n. Whenλ = 632.8nm and n = 1.49, the optimum pit length becomes 106nm.
However, it is almost impossible to make pit shapes where the edges are perfectly perpendicular; in reality they become "mesa" types as shown in Figure 4.17 (b).
Whether pit shapes are good or bad has an effect on playback signal characteristics and manufacturability, and there is a significant amount of tradeoffs for these qualities. For example, it would be better for the playback signal characteristics if the edge angle was as close to perpendicular as possible, but such a pit shape causes a problem where the stampers cannot accurately replicate the pits during the manufacturing process.

(2) Pit shapes and playback signal characteristics
For the playback signal characteristics, the audio/video quality will improve when the signal has more of the AC component (RF signal) and less of the noise component. The size of the RF signal is mainly determined by the pit depth, pit width, and pit length. In principle, the pit depth is determined by the thickness of the photoresist coating, but configurations are made so that the playback RF signal is maximized for discs in consideration of the amount of the coating removed during development and the pit depth reproduction rate during manufacturing. Because the pit shapes are mesa types in reality, the optimum depth for disc pits was deeper than λ/4n, therefore a thickness of 140-150nm was optimal for the photoresistant coating. Similarly, optimization settings are made to the laser power during cutting for the pit width and to the optical modulator duty (duration of the laser being on) for the pit length.

[image omitted]
Edge

(a) Rectangular type pit

[image omitted]
Edge

(b) Mesa type pit

Figure 4.17 Pit shapes (schematics)

In addition, the dimensional accuracy of pits was improved in order to reduce the noise component, requiring a prevention of minor deviations in shapes. To do this, it was important to narrow down the focus point of the laser beam recorder's objective lens as much as possible. Specifically, a laser with a short wavelength (460nm or less) laser was used with an objective lens that had a high numerical aperture (0.9 or greater). Such special lenses were originally for high-power microscopes, and Olympus lenses were used exclusively. Furthermore, a high resolution type photoresist was used to prevent microscopic deviations in shapes.

(3) Pit shapes and manufacturability
Pit shapes needed to be replicated by the stamper as faithfully as possible during the manufacturing process, but there were pit shapes that were easy to replicate as well as pit shapes that were difficult to replicate. Generally, pits with low depths, narrow widths, and rounded edges were easier to replicate.
A stamper that was molded with easy-to-replicate pit shapes had wide margins for the molding conditions, could have short cycle times, and rarely had pit defects upon mold release. The pit defects that occurred upon mold release were called names such as "plowing" and "pit mekure" ("pit curling"), and they occurred when the edges of the stamper's pits scratched the edges of the disc material's pits immediately after molding. With such scratched edges, abnormal waveforms would occur in the playback signal, resulting in a defective disc. To improve mold releasing for such cases, solutions included smoothing the pit edges by controlling the baking temperatures and times when making the disc masters, or putting lubricants into the molding compounds. In addition, if the cycle time was made too short, the pit replication may become softer and the playback signal characteristics may degrade.

(4) Applying Optical Simulations
As previously mentioned, during development trial and error was repeatedly used in a variety of techniques to determine the optimum pit shapes, but computer simulations were also being done at the same time, and these simulations were used in detailed cause analyses and to determine optimal parameters. The paper "Diffraction theory of laser read-out systems for optical video disc", submitted by the British applied physicist H.H. Hopkins in 1972, was the theory that formed the basis for the theoretical analyses related to playback signals from reflective optical discs. Based on this theory and in accordance with the analysis purposes and computing ability of computers, under conditions such as geometrically limited pit shapes or repeating fixed patterns, various analysis methods were developed such as analysis methods for finding solutions in one or two dimensions, using finite element methods or boundary element methods, and methods for finding solutions in three dimensions without limitations on the pit shapes. Various simulations were also done for mesa type pits, and these simulations were used for investigating the optimum pit shapes and cause analysis for problems. Such optical simulation technology was only used by optical device manufacturers in the past, but with the development of optical discs, this technology also became established in electronics manufacturers. This was achieved by electronics manufacturers employing technicians from optical device manufacturers and training their new technicians, in addition to electronics manufacturers and optical device manufacturers working together.

Note: Summary of H.H. Hopkins' simulation technique
By applying a Gaussian distribution function to the intensity of the laser light output from the objective lens as thus:

[image omitted]

The light will reflect off the pit surface and pass through the objective lens, and the intensity of the light that enters the light sensor is represented by the following Fourier series:

[image omitted]

Here, t is time, I0 is the DC component of the detected light, the second and following terms are the AC component (the high-order harmonic RF component), and we get the following:
In addition, R(m,n) is an expression that reflects the pit shape using the reflection coefficient parameter of the pit surface.

Figure 4.18 (a) and (b) show examples of simulation used for cause analyses of color flashes and dropouts.
(a) shows a normal playback waveform, while (b) shows how the waveform changes when the shape of just one pit in the center is molded smaller. (b) is a typical example of symptoms such as "dropouts" and "color flashes", which are discussed in the next section.

[image omitted]
(a) Playback waveform when pits are normal

[image omitted]
(b) Playback waveform when one pit is abnormal
Figure 4.18 Example of a playback waveform optical simulation

In this manner, simulation methods were used to investigate the playback signal wave in relation to various pit shapes (height, width, length, pitch, etc.), and this was very helpful in investigating the optimum pit shapes for obtaining the best playback signal. In addition, by investigating the relationship with pit abnormalities, simulations were used for analyzing quality problems when there were playback signal waveform abnormalities.

4.2.2 Reducing micro-defects
One side of a LD disc has around 14 to 28 billion pits, but it can be said that it is impossible to create a disc that has no pit defects whatsoever. Therefore, cases where there is a defect in a pit and the playback signal becomes abnormal were referred to as "dropouts", and a correction method where the dropout was replaced with the previous line was used (see figure 4.19 (a)). However, if the size of a defect is the same size as a pit or less, or if part of a pit has changed shape, the defect will be reflected as-is in the video signal without dropout correction being used. In such cases, the phase of the playback signal's RF waveform will be out of phase, therefore one pixel and the surrounding area will appear as a bright, differently colored point when looking at the video. This defect is called "color flash noise" and has an appearance as shown in Figure 4.19 (b).
After investigating the causes of color flash noise, the following three factors were almost always reasons:
① Imperfect pit shape: An RF signal was output but the amplitude was insufficient.
② Foreign material inside the plastic layer: When noise occurs due to colored foreign material, the focus is lost due to the different refractive index of the foreign material in the plastic, causing insufficient RF amplitude.
③ Degradation of the reflective aluminum layer: Sub-micron sized corrosion or exfoliation occurs due to the passage of time, resulting in noise.
① and ② do not change over time, and defective products do not normally make it to retail markets normal quality inspections. The cause of ① was determined to be mainly due to micron sized or smaller defects on the glass master surface during the mastering process, ultra-fine impurities (organic materials or particles) in the ultrapure water or chemical solutions used during various processes, etc. Therefore, by using a higher grade for the relevant materials and being thorough in product quality control, it was possible to prevent color flash noise from occurring. Similarly, ② was addressed by mostly eliminating foreign/residual materials with the help of plastic manufacturers, which in turn mostly eliminated color flash noise. ③ is related to reliability (life expectancy), which is discussed in the next section.

[image omitted]
(a) Dropout (after correction)
[image omitted]
(b) Color flash
Figure 4.19 (a) and (b): A dropout and a color flash

4.2.3 Reliability (life expectancy)
LD discs are a "non-contact format", therefore it was often said that one of their qualities is that they are an "almost permanent" storage medium, with hardly any degradation over time. Unlike "contact formats" such as video tape and VHD which had unavoidable degradation due to friction, LD discs were a "non-contact format", qualitatively implying that friction was not a problem for this "almost permanent" medium. Starting from the R&D stages of LD, there were technological development and evaluation testing done in order to preserve the reliability of LD discs, but in actuality, verifiable results could not be obtained until several years had passed since LD products' marketplace introduction.
One factor that had a large effect on the reliability of LD discs was something that was called "snow noise". Snow noise was a type of color flash noise that occurred due to the sub-micron sized corrosion or exfoliation of the reflective aluminum layer over the passage of time. One difference from the color flash noise mentioned in the previous section is that snow noise appears as flickering snow across the entire screen, and another difference is that the symptoms do not appear immediately after production -- rather they increase gradually over a period of months/years. In addition, this defect was bothersome because instead of appearing on all of the discs manufactured in the same line, it only appeared on some discs. Consumer complaints of snow noise occurred through the first half of the 1980's, but the cause was narrowed down and solutions were implemented in the latter half of the 1980's. Meanwhile, testing methods were established and gradually refined. As stated in the previous section, the cause of snow noise was degradation of the reflective aluminum layer over the passage of time. Investigations revealed that the coating of the reflective aluminum layer was improper, and miniscule changes might occur over long periods of time. These miniscule changes refer to compressive stress due to the growth of the oxide coating of the reflective aluminum layer, causing sub-micron sized exfoliation or aluminum oxide crystal growth, resulting in cases where noise would occur during playback. Because these are microscopic changes, a disc would appear unchanged to the naked eye, therefore analyses were performed with optical and electron microscopes. In addition to suppressing the oxide coating growth and relieving the compressive stress that occurs, it was necessary to establish coating guidelines that would increase the adhesion to the plastic base plate in order to stop these microscopic changes from occurring over time.
The coating guidelines for the reflective aluminum layer were optimized by using different guidelines for trial manufacture then repeatedly performing testing by evaluating the life expectancy after exposure to heat/humidity/acceleration. Some of the process guidelines that were most effective were ① the storage environment of the plastic base plate immediately before vapor deposition, ② the degree of vacuum during vapor deposition, and ③ the vapor deposition rate. In addition, ④ using an alloy doped with approximately 1% of other metals was determined to be particularly effective in regards to the vapor deposition materials (aluminum chips).
For the plastic base plate in ①, moisture absorption was performed on the clear base plate after molding for 15 minutes or more in an environment with a relative humidity of 60%, the aluminum oxide coating adjacent to the base plate was sufficiently grown immediately after vapor deposition, preventing successive growth of the oxide coating.
For the degree of vacuum and vapor deposition rate in ② and ③, a high degree of vacuum and a high speed vapor deposition rate resulted in the aluminum oxide coating becoming a single layer of columnar crystals, allowing for compressive stress from successive growth of the oxide coating to easily occur, but with a low degree of vacuum and a low vapor deposition rate, a laminate of fine granular crystals occurred, preventing compressive stress from occurring.
For the alloy used in ④, the materials themselves prevented growth of columnar crystals and were used for creating a laminate of fine granular crystals.
Figure 4.20 shows cross-section images of the reflective aluminum layer before and after the improvements.
Through these improvements, the snow noise problem was solved, allowing for LD disc life expectancy to reach a level where no practical issues should occur.

[images omitted]
酸化被膜
Oxide coating

柱状結晶
Columnar crystals

ディスク基盤
Disc base plate

(a) Structure of the reflective aluminum layer immediately after deposition

酸化被膜の成長
Growth of the oxide coating

圧縮応力
Compressive stress

(b) Growth of the oxide coating after deposition

酸化アルミニウム結晶の成長
Growth of aluminum oxide crystal

剥離
Exfoliation

圧縮応力
Compressive stress

(c) Exfoliation and growth of aluminum oxide crystal

酸化被膜
Oxide coating

粒状結晶
Granular crystals

基板の水分で形成される酸化被膜
Oxide coating formed with moisture on the base plate

ディスク基盤
Disc base plate

(d) Structure of the reflective aluminum layer after improvements
Figure 4.20 Cross-section images of the reflective aluminum layer improvements
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