JPS60500104A - Coated media for optical recording and related coating technology - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] coated media for optical recording and Coating technology related to it The present invention relates to a novel high-density information storage medium, and in particular to a recording layer suitable for optical data recording. Coatings and protective overcoats to enhance the recording properties of media containing Relating to something that has the means.

Background of the invention Optical storage of digital data is a relatively new technology and requires specialized (OD D. "Optical Digital Data") Using an ODD disk, for example, and optical technology. It is a technology related to the storage and reproduction of digital information that utilizes digital technology. be similar Traditionally, such data is not commonly used in today's high-speed digital computers. stored on magnetic media such as tape or disk used in

What is described here is a sensitive optical recording medium for digital data. An attempt to create a medium that resists oxidation or environmental degradation. Therefore, the sensitivity can be improved and the contribution can be extended, and even more than the current one. This simplifies the manufacturing process.

Various types of protective overcoatings for such media are available, especially for For example, the ideas that have been proposed by engineers regarding the Mirror “Effective optical information storage”, 5PIE Vol. 177.1979 ．． 11.56 or less; 13 Artolini's review of optical recording media "Optical Memory Materials and Methods", 5PIE Vol.

123, 1977. 'D, 2 or less; according to Cochran and Ferrier “Fused pores in metal films for real-time high-density data storage”, SP IE Proceedings, August 1977, p. 17~ 32: and other references below).

Long storage life: Optical data storage technology is attractive. Because it has a large storage capacity This is because there is. Optical data discs, such as those considered here, have a long storage life. The goal is to store information throughout one's life, and the goal is to 5-10 years or more under typical or harshest operating conditions for That's all. Engineers have been striving for this for a long time, but such long-term lifetime remains an unmet goal in the art. The present invention The aim is to create an improved ODD media that is more suitable for shelf life such as It is a medium suitable for ``optical mass memory'' and such applications, and has been improved. Emphasis is placed on overcoat and/or spacer means.

Therefore, as a feature here, we are looking for records that exhibit a favorable long-term archival life. utilizing novel spacer and/or overcoat structures and materials for Intended. That is, the record typically It exhibits high resistance to oxidation or environmental degradation. Therefore, long There is little or no loss of information recorded over the shelf life of the period. It has a reflectivity that is stable enough to be 'read out'. such a practical memory Media or associated systems have not yet been available, especially those with "good" sensitivity. This is especially true if you are being asked to do so. The present invention represents a means towards this goal.

“New Path Spacer Layer”: Further according to salient aspects herein, a spacer layer (e.g., such a (in a ``cum mirror'' structure) is preferably a ``soft pad'' deposited on the reflector layer. on which an absorbent (recording) layer is then superimposed. This spacer layer It is made of a fluoropolymer precipitated in such a way that it has the intended read and write properties. Highly transparent for wavelengths and by separating the absorber layer from the reflector layer Provide good thermal and mechanical insulation (otherwise the reflector is usually highly conductive) Since it is metal, it acts as a heat sink and transfers the recording energy to the absorber layer. leakage and reduce its efficiency).

Thus, as will be discussed further below - by way of example we Oloethylene (PTFE) or fluorinated ethylene propylene copolymer (FEP) ) prefer vacuum-deposited fluoropolymers.

Hard silicate coatings (silicon oxide or silicon oxide) are used as such spacers. Specifying silicon oxide (see “fused silica”) is more of a conventional technique. (e.g., U.S. Pat. No. 4,195.312 or 4,195.313 or 4.216.501). however , such materials can satisfy all of the thermal and mechanical objectives set here. I can not do such a thing. For one, such silicate coatings are easily exposed to heat. convey too much. For example, a “low-energy recording pulse (approximately 40 nanoseconds) (output of about 100 nm) is achieved when a single 1/4 wavelength optical thickness of 5io2 is used on the Ant reflector. It is difficult to record when This very thin spacer layer is clearly Too much heat for recording (dissipation and waste).To prevent this, more It is of course possible to use a thick spacer layer, but a thick SiO2 layer cannot be manufactured. Complicating the manufacturing process and lowering quality. It is particularly important that the layer generally restrains the absorber. This is because it reduces the sensitivity and narrows the bandwidth for obtaining low reflectivity. (Design and production of tellurium optical data disks by J.Rancourt) 5PIE Proceedings; Lz-V Skills>Advances in Technology , Vol. 299.1981. (See p. 57) Furthermore, if several well-separated If a read/write (R/W) wavelength is used, the “minimum value” of the required wavelength The creation of spacers is difficult because the “thickness” control is required for precise setting. It becomes even more complex (the light energy is efficiently combined with the “triple layer” absorption layer to create a big effect). It is believed and intended to "write" by increasing the reflectivity at the target location. An unwritten background of relatively low reflectivity at the R/W wavelength )

Conversely, a single "soft pad" (e.g., a fluoropolymer) that takes advantage of this teaching ) The spacer has little effect on the sensitivity, and it is a single quarter wavelength. gives a wide reflectance minimum value (λ) and therefore supports many R/W wavelengths at the same time. and function.

One aspect of this disclosure describes the preparation and use of such "soft pad" spacer materials. The purpose of the present invention is to teach and demonstrate related precipitation methods, particularly for such O A D disc is suitable. More specifically, it generally There is a convenient λ for low-energy recording using laser equipment (e.g., 5 to 20 m　W/40n　, sec pulse He-Ne laser writing; 25MHz class Harusho).

Overcoat; General: The spots (pits) so recorded are approximately 1 micron in diameter. is intended. However, dirt on the surface (e.g. oil or fingerprints) or airborne Particulate contaminants such as dust from For example, normal smoke particles have a particle size of about 6 microns. (6 μm, or approximately 240 microinches) in diameter. therefore, If one or several such contaminant particles just rest on the overcoat. If so, those particles generally act as a “mask” to reduce the recorded “bits” (data) will be erased.

Therefore, such pollution particles and all dirt, smudges.

Traditionally, thick overcoating layers are used to defocus or defocus dyeing. It was getting worse. For example, transparent overcoats on the order of 10 to 180 microns thick. It had been coated. Therefore, resting on the surface of such a protective layer Any dust particles that are removed (not wiped) are 'defocused', i.e. , those dusts are in the focus of the objective lens used to detect the recorded data. It optically "disappears" by being removed from the range or optical aiming position.As a second purpose, Such an overcoat provides mechanical protection and handling protection for the recording layer. damage during manufacturing, testing, or use) must be prevented. do not have.

By the way, in some cases engineers have used relatively hard materials as transparent protective overcoats. In some cases, we have proposed materials with a "high quality" quality, while in other cases we have presented materials with a "soft" quality. For example, some are from CGE, which presented an elastomeric outer coat. silicone rubber such as ``lastic RT V'': US special rubber such as 3el1 No. 4.101, see No. 907; The ``absorber'' that can be scraped is overcoated with a ``barrier layer'' of s+02 or This is overcoated with a barrier layer of sucrose or resin acid derivatives. are supercoated (overcoated) with such silicone resins). but, The well-known overcoating of soft, elastic (rubber-like) materials is “sticky” Features an exposed surface that easily attracts and retains dust. another example In this case, no such “elastomeric coating It seems to "restrict" the underlying absorbent layer.Additionally, the elastomer is too expensive. some require a curing temperature of It will take a considerable amount of time to cure, and when heated for ``early curing,'' They pose a serious risk of overheating to the triple layer (silicone like RTV). Elastomers exhibit all of these drawbacks, as well as being subjected to hardening stresses and excessive stress during use. with excessive moisture absorption).

On the other hand, other engineers have developed a ``hard'' external ``seal'' overlay that is layered directly onto the absorbent layer. I thought about the coat (for example, B art.

“The emergence of optical disk systems” by L.ini, etc., IEEE3 pectr. See um, Agust 1978; according to it, it has a ``trilayer'' structure. 5iOz is applied on the top and bottom of the titanium absorber). But they A hard overcoat such as It even goes so far as to make it unrecordable, and it seems to deteriorate the green sensitivity (possibly). (This is because the overcoat presses down and restrains the absorbent body without deforming.) I had to admit that. Additionally, hard external coatings such as 5iOz Too absorbent (e.g. water vapor absorption) for long-term use.

“Hard/Soft” overcoat: Accordingly, another aspect of this disclosure overcomes most or all of the aforementioned disadvantages. The objective is to provide an overcoating to be removed. It's a ``soft bad'' Provides a two-part overcoating consisting of an inner layer and a hard outer sealing layer. This is done by having a ``hard/soft'' overcoat. The inner pad is a ``soft cushion'' that deforms (and is easily compressed). It is intended that the adjacent absorber deform or move during burning heating. and at the same time also provide good thermal insulation (very low thermal conductivity) Characteristic: Relatively low specific heat>. Simply put, this "soft pad" is mechanically and thermally It isolates the absorber well, while the “hard” outer coat gives optimal mechanical protection ( For example, a seal against the ingress of steam). Of course, such layers bond well. must be transparent and highly transparent for the intended read/write wavelength. It must be convenient and inexpensive to use.

As mentioned, such a “soft pad” (e.g. FEP or P The mechanical properties of the EFE (see below) depend on the movement of the underlying absorber during "write heating". It seems to accept deformation better (e.g. as a “top pad”; (If the soft material is also used as a “spacer,” it can also be used as a “bottom pad.”) . Such "soft pads" clearly protect the absorber from its surrounding environment mechanically and It can be seen that 'sensitivity' can be significantly increased due to thermal separation (e.g. melting than would be expected using only a “hard” overcoating such as silica. The latter one is better, that is, the latter one consists of a bit or a ``write''.

(requires more energy to do so). ``Soft pad'' Because it is very effective as a material release agent (e.g. with SiO□ on the absorber), Even if it is only used as a “spacer” for layers (e.g. it is ; It was found that the sensitivity was increased (compared to the case of replacing with 02 spacer).

Also, as discussed below, such ``soft pad'' coatings are preferably by evaporation using essentially the same equipment used to deposit the absorber layer. applied as a fixed film (e.g., associated subsequent analysis using common equipment). (by exit step). The resulting convenience, cost, and time savings are It should be obvious. According to this characteristic, we have made these to be tough ゛soft pads. Examples of preferred materials that meet most or all of the requirements (including vacuum deposition) The aforementioned fluoropolymers (FEP and PTFE) were discovered. and convenient The good thing is that the same soft padding material is on both sides of the absorbent body (i.e. on both sides of the absorbent body). It can be used as a coater and overcoat. Instead of this, plasma polymer Polymers of the agglomerated type, such as polyethylene or Pary! ene” (Trademark, from Union Carbide Company as Baraxylene, U.S. Patent No. 3.34) 2.754) may be used. Preferably, such a “soft pad” layer The same equipment used to deposit the absorber layer (and/or spacer layer) It is given at the same time using the position.

This “soft pad” overcoat layer preferably overlays the absorbent layer in any manner. coating (particularly a hard paradopa layer applied on a soft paradopa), but also thermally and mechanically for mechanical separation and must be conveniently joined to the underlying absorbent layer. Must be. Sensitivity is not degraded by this, and the absorber is made of a hard “outer”. layer” is properly “separated” from the overcoat and its hard overcoat. ting and/or any stress on it may bind the absorber and cause the bit shape to prevent interference with development. In addition, the "soft pad" overcoat "peels off" during use. It is well bonded with a hard coat to prevent moisture from entering. .

These peelings, moisture intrusion, etc. can easily destroy the desired optical properties). That's it It is important to protect the absorbent material from any harmful effects such as deformation and/or is important when using a displacing absorber. Hard oil applied directly onto the absorber An absorber coating (e.g., the well-known 3i0 or SiO□) covers the absorber layer. It is possible to restrain such deformation and movement during "bit writing" by restraining the technology. It would be obvious for. Therefore, it interferes with the bit formation and sensitivity This also degrades recording efficiency and requires more writing energy. Also, Haton Which silicon oxide absorbs too much moisture. We are on a “cold” substrate I experienced such problems with 5i02 deposited on FEP or PT Materials such as FE (which under similar conditions can form relatively “porous” films) ) was far less problematic.

Therefore, the technical speed of sound is determined by the importance of a suitable “soft pad” of the type mentioned above. will find it useful, especially that it improves the recording efficiency of the adjacent OD absorber layer. This is useful when trying to increase the rate. Therefore, another form of this feature is to provide a ``soft pad'' coating on the absorber layer and is also possible. In some cases, common deposition techniques may be used. One of the relevant characteristics is In some cases, providing a similar "soft pad" spacer layer under the absorbent body, This allows the absorber layer to be thermally and mechanically isolated from interference arising from upper and lower layers. Ru.

Relevant features include, for example, a good vapor barrier, a mechanical ``cover'' and an antistatic surface. to act as a surface and to “defocus” dirt on the surface. A “hard” layer is placed on the outside of this “soft pad” to form an optical layer.

layering a protective overcoating (i.e., “hard/soft” overcoating). (Bacote).

Another improvement to the above, a ``soft pad'' of fluoropolymer It should be soft enough and easy to deform, and the adjacent Mechanically separates the absorber layer so that it can move freely during writing. and thermally isolate it (i.e., as a “spacer” in the lower layer) or as a “soft overcoat”, or both. do).

Another improvement is to provide such “soft pad” spacers using an organic layer of The organic layer must adhere strongly to the underlying reflector layer. At the same time, it adheres with some strength to the absorbent layer layered on top of it. It is. And the related feature is such a "soft pad" overcoat. It consists of a hard overcoat and a relatively sturdy one. The absorbent layer is bonded with the absorbent layer, but with a different strength from that of the underlying absorbent layer.

New “Hard” Super Coat: As mentioned above, another notable feature here is the soft padding described above. ``The overcoat is preferably super coated with a ``hard'' outer protective layer that is compatible with It is to be exported.

Additionally, as a more unique feature, a new class of ``irradiation-cured polymers'' is described here. Such “hard” outer coating for archival OD (optical data) discs and preferred novel methods related thereto. are being considered for coating such discs using materials such as .

The preparation of the novel prepolymer is described below. (see, for example, mixture H-1). It is such an OD disk (long term Such a ``hard'' protective overcoating for recordable shelf life etc.) It is shown in Figure 3 that it provides, especially on such "soft pad" overcoat. It is intended as a super coat. More specifically, it is surface dust. (for example, size up to 6 to 8 ml (1/1000 inch)) A thick ``transparent'' coating that helps focus the intended R/W waves. It is intended to provide long-term translucency) and further protect against mechanical interference or Against vapor ingress (especially water, water mist, sulfates, NaCl or other chlorides) It is intended to provide an environmental barrier for It is rather a well-known overcoat. It is intended to work like a piece of glass (e.g. glass) and is protection. This allows the disc to be pressed down a little, but It is not necessary to withstand conscious cutting movements such as fingernail scratching. Without a hard supercoating, the soft FEP layer can be easily wiped off. ).

Well-known hard overcoating: The technology in this field of technology considers various materials for similar protective coatings. came. For example, “fused silica” (s+02, or SiO) Overcoats in the form of "vitreous" have been commonly proposed, but for the present purpose (O D disk, etc.), these seem to be disqualified. For example, they are one They are generally highly porous and can trap too much moisture. Therefore, they are There is a strong tendency for cracks to form due to swelling (SWell) (especially in the severe temperature/humidity conditions mentioned above). (under cycling tests), and such moisture contamination can significantly alter the optical properties. cause serious deterioration. Furthermore, they are not optimal with respect to the required vacuum deposition. (eg impractical for a few mils or more).

In addition to such inorganic overcoatings, the technology Several organic materials were considered to provide a protective overcoat. for example As mentioned above, the technology consists of silicone rubber and similar elastomers for this purpose. We considered using a stomeric polymer. For example, conveniently! hardens at temperature These are the types of plastics that are obtained and generally they contain harmful substances like acetic acid during curing. liberate contaminants (or the “plastic” method of Yoneda Patent No. 4,334,233). (see "Book Sheet").

With a similar intention, we considered using the well-known fluoropolymers. , an intended thickness of 6 to 3 ml), a typical fluoropolymer analysis The method of output is preferably not zero. For example, it generally requires a lot of solvent splashing. (See the problems with solvent splashing and related shrinkage discussed later.) ). More importantly, this requires intense curing heating (approximately 390°C). 0, while the OD disc and its associated coating number should be above about 66°C. X(1) (e.g., at temperatures above Coatings such as soft FEP overcoats and absorber layers will be destroyed. (and/or its components may move). Furthermore, that Such polymers present a ``sticky'' and dust-retentive surface, and the read/write It is considered that the material is optimally transparent at wavelengths including 600 to 900 nanometers. It has not been achieved.

Furthermore, various “solvents” have been considered for such hard protective overcoats. base” (solute-loaded) polymers. However, these dry (curing) results in the dissipation of most of the solvent and is accompanied by large, problematic shrinkage. ′ Therefore, these materials seem to be disqualified, especially for coats of the intended thickness. (Also, such thick coats of these materials bubbles will probably form during the heating process). further considered is a variety of two-part cure polymers such as “RTV-6” (by GE). be. However, these are somewhat difficult to apply and are generally relatively expensive. have a high viscosity (possibly soften enough for quick and smooth application) (as in, they require heating, which is a problem). Also, they generally have “outgassing” problems Furthermore, many of them cure relatively slowly at relatively high temperatures. (e.g. 15 minutes at about 66°C, and the cured material is (often exhibits a sticky surface and is easily scratched and easily peeled off). difference Furthermore, such materials generally have too short a pot life. fe)” (daily order), and also has shortcomings in granting There is.

Another type of protective material considered is of the PVC (polyvinyl chloride) type. However, these do not seem to be practical. This is because they use solvents. and, more importantly, they generally crystallize over time and become less forgiving. This is because it results in optical "dichroism" that cannot be tolerated. This “dichroism” would interfere with the transmission of the required read/write beam (follow-up/write laser beam has already been polarized, and the crystallized overcoat cannot be recognized by the technical speed of sound. (which would obviously cause optical problems). The preferred radiation curing a Kurirupo 1 Tsuma [does not seem to cause the above-mentioned problem, even if it (They do not crystallize and do not cause the problem of ``dichroism'').

Preferred materials for “hard overcoats”: As a result, chemical Coating (not very desirable. ``Irradiation hardening'' type coating 1) J-retai Attempts have been made to use monomers such as acryl-normonomers, or various a prepolymer mixture containing additives; similar to “mixture H-1” discussed later ). I was somewhat surprised [but such an overcoat is properly granted] (see, for example, the ``Spiral'' technique described below; appropriate ``Setting Fields'') The above-mentioned requirements (if all It can be satisfied even if it is not (Matonto), while other material numbers can be satisfied as well. It doesn't seem possible. Therefore, another purpose of this disclosure is that Such as ``hard'' protective overcoat for optical data disks such as teaches the use of radiation-curable polymers (especially acrylics), and further develops them into m& ! The purpose is to teach related methods of applying

As detailed below, the preferred hard coat material is a radiation-cured polymer of ) is made up of many ``acrylic monomers'' (or ``brevo IJ mer'') , i.e. oligomers or resins to be further polymerized; especially if the main components are suitable for acrylates or acrylamides). Preferred prescription (mixture day -1) is a suitable Acrylic IJ J-repoxide and acrylic acrylate. comprising a fluorine crosslinker and an associated acrylate diluent and photoinitiator; More preferably, a predetermined "setting surfactant" is included. Also, the mixture A small portion (well, 10%) of the compound consists of one or more additives. (preferably organic substances that participate in UV polymerization, such as Gf styrene or is a similar vinyl ether).

Some reason why such acrylic? It is clear that +X et al. are very appropriate. It is. In other words, many of them contain problematic ingredients such as “shrinking solvents.” and they do not require problematic curing conditions (e.g. excessive heat). stomach. They are fitted with a final “hard” polymeric overcoat that has properties that allow them to be fitted. It seems particularly suitable for giving.

In addition, such “acrylic radiation-cured polymers” (also called “hard optical polymers”) It will be recognized that almost all of the other requirements of "Bacote" are satisfied.

That is, they do not crystallize easily and they do not contain significant solvent components. or without the shrinkage problems associated with them Curing quickly and conveniently, they are also relatively easy to apply (e.g. e.g., as a low viscosity monomer solution). They are susceptible to corrosion and deterioration due to normal environmental substances. They appear to be particularly good in their resistance to They are not easy to absorb dust or dust, and unlike ``two-part curing'', they are not easily spread. Compatible with a range of additives (e.g., as seen in the examples below) curing is not affected by additives).

Technological speed of sound is claimed for curing irradiation of a few seconds to the source (appropriate λ and intensity, etc.) It is cheap, quick and convenient like exposure between It will be recognized that it can be something that involves only shrinkage. Or, If radiation is not a primary concern, consider electron beam or gamma irradiation instead. Therefore, it can also be hardened. Alternatively, if there is also a peroxide (catalytic) cure is possible. Also, whatever the predominant curing mode, It is reasonable that supplementary heat of the light may be applied to accelerate the completion of curing when It will be understood.

Assignment as a spiral: According to related characteristics, such acrylic overcoat polymer preferably It is applied in a spiral onto the main substrate disk and evenly distributed over it. (e.g. rotation of a suitable disk) Containing a setting agent) allows for even flow and fixing. It can be seen that the mixture spreads over this surface with great smoothness and uniform thickness. .

For example, it may be a donut-shaped disc several inches wide (e.g., 14 inches wide). ±0.7 to 7.0 in 7m11 coating over the outer half of the disk Microns, which give rise to small thickness variations. This is completely surprising. Current The technical sonic speed of the technology is that such acrylic coatings or other coatings The simplicity of such coating techniques, whether related to and the novel advantages are quite remarkable.

Surprisingly, the invention related to the above-mentioned special "setting agent" It provides a significant degree of useful surfactant properties, such as enhanced resistance and planarization. In addition, the mixture is set. i.e. giving rise to a series of spirals , once attached to the host disk, until it flattens itself (or if It "sets up" and remains in place until it is brought into contact with a oxidizing solvent. That's it It can be seen that this "setting effect" increases the simplification of the coating technology. Probably. For example, in the process of assigning these spiral columns, host disk without asymmetrical deformation or movement of the material due to associated centrifugal forces. Allows the surface to rotate slowly.

One variation of this novel application technique involves a "solvent planarization" step, which The column of the mixture imparted with ) becomes “wet” and spreads over its disk surface with remarkable uniformity and speed. It becomes possible to be Special solvents have been proposed for this purpose, and the preferred It is particularly suitable for coating materials and substrate surfaces.

Therefore, one objective here is to provide the aforementioned and other related features and advantages. It is to be. A more specific purpose is to provide a soft pad adjacent to the optical recording layer. “To do so while teaching the use of materials. Another purpose is to Not only is it suitable for recording sensitivity and low power lasers, but it also has a long service life. It is to show. Yet another objective is to use fluoropolymer materials to teaches the preparation of such “soft pad” layers deposited by vacuum evaporation in Is Rukoto. Another purpose is to provide such “hard” overcoatings and It is an object of the present invention to provide related preferred materials and application techniques.

Brief description of the surface These and other features and advantages of the invention are considered in connection with the accompanying drawings. By reference to the following detailed description of the preferred embodiment, the technology will be better understood and recognized. In addition, similar reference numbers in the drawings are the same. Showing elements.

FIG. 1 is a cross-sectional view of an idealized portion of a recording medium according to the prior art.

FIG. 2 is a similar diagram of an embodiment of a new preferred recording medium showing a structure according to features of the present invention. This is a diagram.

FIG. 3 shows a preferred method of applying an overcoat material according to another feature herein. 1 schematically illustrates the method; FIG.

FIG. 4 is a highly idealized cross-sectional view of the material so applied.

FIG. 5 is a similar cross-sectional view under partially modified conditions.

FIG. 6 is a diagram showing the change in outer coating thickness.

Figure 8 shows the rotation speed of the table and the speed of the arm as a function of the radial position of the disk. FIG. 7 is a diagram showing these values.

Typical OD record (Figure 1; triple layer with "overcoat"): One preferred use of such a "soft pad" is in the digital The well-known “dark mirror” (or adjusted It is used as a "spacer" in the "31") structure. This spacer is media (e.g. exploits the “dark mirror” effect; see other references in this article).

Some examples of preferred embodiments of such "soft pad" spacers are described below. Before proceeding, the function of the typical ``trilayer'' optical recording structure shown in Figure 1 will be briefly explained below. Simply state.

Figure 1 shows a cross section of the optical data disk R-dd in a schematic and idealized manner. It is depicted in , and covers the substrate disk S that supports the recording triple layer. It will be seen that a protective overcoat 100 is included. Disk R-dd is a well-known method that irradiates a beam LB onto a triple layer to record the bits consisting of it. that it is intended to be used for recording by a light source (laser L); As can be seen (see sample bit hole 98-a in absorber layer 98).

These bits are "read" using certain associated detection means (DET).

The wavelength of the readout laser beam (LB in Figure 1) is the same as the one recorded on the disc R-dd. The area is chosen to indicate the required anti-reflection condition. The read beam intensity is is kept low enough so as not to disturb the integrity of the data recorded on the disk. sub Straight S is preferably a conventional magnetic recording material with a smoothing layer 92 if necessary. It consists of a disk 90. The triple layer is a transparent space on the reflector film 94. A suitable absorbent or recording film 98 including a layer 96 and laminated thereon. It is equipped with

Therefore, the reflected read beam is e.g. , intensity modulated by an optically detectable change in the hole "98-a)" You will see that. For example, the readout beam is "1 bit" (e.g. When irradiating hole "98-a), it received a relatively high reflection and was not written. receive relatively low reflections when illuminating areas that are not covered. Protection H100 is the Dust particles on the top surface are displaced far from the focal plane of the optical system (i.e. (placed outside the point) is selected and placed so as not to affect recording or reading operations. .

Traditionally, "writing" (i.e., in the reflective capacity of the thin film absorber layer 98) The absorber is exposed to a laser beam that produces a mechanically detectable disturbance. The film 98 consists of a predetermined (minimum) value at a given bit position (98-a). ) is considered to have to be heated to the writing temperature (Tw). Minimum temperature T The level of w depends on the characteristics of the absorber 98 (e.g., its thickness, metallurgical properties, microstructure). etc.), and also depends not only on the characteristics of the lower spacer 96 but also on the spacer 96 and absorption. depending on the "interfacial properties" between the absorbent body 98 and the overcoat 100 and the absorbent body 98. It is thought that it may also depend on the interfacial properties of the

``Bit position'' (e.g. where the writing laser beam is considered to be focused) For writing to area 9.8-a), this required minimum recording temperature = lTw is reached. You will see that it takes a finite amount of time to do this. However, “bit position” While the station 98-a is so heated, the It escapes through the 1m spacer 96 (perhaps also through the spacer 100) underneath. It is considered to be “wasted”. Of course, as long as heat is lost that way, More time/energy is required for “writing”, i.e. more time/energy is required for “writing” Sensitivity deteriorates. Also, such heat loss reduces the quality of the recording and This is thought to reduce the "recording density" of the medium.

Soft pad as "trilayer spacer": Preferred material: According to the invention, it consists of A “soft pad” (e.g., fluorocarbon polymer) material It has been discovered that it can be advantageously used as a body spacer layer 96 (FIG. 1). stop Importantly, the use of such "soft pad spacers" significantly reduces write energy. It has been found that the wastage of loss of write energy).

One preferred material is PTFE (polytetrafluoroethylene) polymer. Well, the other one is FEP (fluorinated ethylene propylene) polymer. commercially (e.g., under the name 1 “Teflon”, a trademark of the DuPont Company). It is a “fluorinated polymer” that is available. Such a fluorinated polymer can be used as a reflective layer 94. (Fig. 1) can be deposited as a thin homogeneous layer on, in particular, e.g. This can be accomplished by vacuum evaporation from a suitable melt as discussed. the Such coating materials are considered to be in a ``vacuum evaporated/deposited'' state. . because they are considered to be in a ``modified'' state after such precipitation. This is because they are being given.

Sample O; Comparison standard (SiOz spacer): Preparation of triple layered plate: (Figure 1): An aluminum plate suitably smoothed with a subbing (5ubbin()) layer 92 such as A reflector 94 is applied on the disc 90 .

Aluminum 94 has a large coating distance and substrate for increased uniformity. Corresponding large batch type coating chamber with “2 type rotation” of high speed. It can be evaporated in a high vacuum in a vacuum chamber. All dust and dirt on components must be reduced to an absolute minimum using rigorous “clean room” techniques. stomach.

Spacers 96 are similarly deposited on reflector 94.

In this implementation, the spacer 96 is Acts as a transparent dielectric material.

used for that purpose (e.g. for writing/reading at λ=6328A) from (Note: From an optical point of view, a spacer with a thickness of ts = nλr/2 will “disappear”).

The absorber layer 98 is formed on the relatively flat (~≦λ/20) recording surface of the spacer 1ii96. It can be thought of as consisting of a relatively thin layer of tellurium deposited (thermally evaporated) on the surface.

Here, a film of tellurium on the order of 50A thick is considered an exemplary absorber layer. It will be done. Similar uses of tellurium are known in the art today (e.g. See, for example, the above citation: also by Ash and A11en "Optical properties of tellurium films", 5PIEp roceedings , #222, 1980: and "'Tellurium Light" by Rancourt. “Design and Manufacturing of Scientific Data Disks”, 5PIE Proceedings, #2 99.1981).

Tellurium or other "absorber metals" with low melting points and low conductivity are generally used for technology Liked. Because it shows excellent sensitivity and the required (threshold) (d) This is because it is considered to minimize the laser writing output. its poor record keeping; Due to its nature, it is not particularly recommended here. But it's a technology Since the speed of sound is well understood (the ``deformative'' hole formation mechanism is here Well suited to use the benefits of ``Soft Pad Supercoat'' as taught. This is very useful for the purpose of explaining the present invention.

For example, in Be1l and 3artOIini U.S. Pat. No. 4,222°071, A similar tellurium recording film is suitable under the assumption of an optical efficiency of about 20%. A laser power of the order of 15 mW is used for writing on it in order to achieve a It is described as requiring force. The goal is to reduce the recorded video signal to approximately The goal is to enable playback with an S/N of 40 to 50 dB or “broadcast quality.” Ru. U.S. Pat. No. 4,222,071 also describes a similar structure and According to a solid-state Ga-A-AS injection laser, a disk A continuous R/W beam of about 1 micron in diameter is directed onto the recording surface while the (or see the video recording material of U.S. Pat. No. 4,334,299).

Here, the test record is a gas (He-4Je) laser operating at 6328A. Recording exposure of 30 to 470n, sec using a beam (usually 10m, 4 at W On, sec or approximately 4001)J). This is the same or similar Use a laser device to produce the smallest reasonable readout (or about 40 dB S/N) It is intended that J = 10-” watt-sec or watt-sec (here 1) ). In this intended setting, the laser beam is 1/2 to 1 micron focused on the bit position of diameter (i.e. 5000-10000A). It is intended to be a write pulse of approximately 4 On, sec length. Ma This is due to the rotation of the 18Q OrpHl disk and the related galvo mirror ( (galvo-mirror) adapts to the characteristics of the focus.

The record R-dd (FIG. 1) is so recorded thereon. For literature etc. For comparable situations in The film must be heated sufficiently to melt and produce the well-known "bits" or "craters". , with very little ゛° noise but good succession (e.g. λ=6328A gives about 50% bit reflectance against 1-3% background at I found out that I can get it.

Below are preferred embodiments for multilayer optical media using "soft pad" materials according to the present invention. There are many examples of such structures.

Sample ■ (FEP as a spacer): Sample O (except as explained below) comparison criteria) are replicated.

In this case, the optical data disk is constructed with a polished glass substrate. The substrate is coated and then the aluminum is coated with about 1 100A thick “soft pad” FEP (fluoroethylene) as spacer layer (propylene) copolymer is layered, and approximately 66A thick is placed on the spacer. A tellurium absorber film is placed. The reflector, spacer and absorber layers are , according to good practice as described above, by vacuum evaporation using a single common equipment. is precipitated by a single continuous procedure.

To most dramatically demonstrate the thermal effectiveness of a “soft pad” spacer, the minimum lateral Absorbers with heat loss must be used. Te is actually not optimal. However, I will mainly present it here. Because the speed of technology is very accustomed to it. , because its useful performance is also known.

Of course, Te, as understood here, does not have good "record keeping properties" and Therefore, other absorbers may be indicated if long-term "record life performance" is required. See references by R ancourt, A, sh, etc. cited in ).

Technology The speed of sound increases by depositing a thin layer of organic material such as FEP or PTFE onto an Am film. You will be familiar with the preferred method of forming by vacuum evaporation (similar (See RajlQOurt's literature cited with respect to). Preferably the material The resistance wire is heated in a "boat" or such container within a high vacuum chamber.

For example, FEP rods are cut to a convenient size for placement within the boat. . The boiling point of FEP is very low, so a relatively small amount of heat is required to vaporize it. Or don't need it. Electron gun evaporation is undesirable because it will decompose the FEP. This is because it is waxy. In addition, if the Similar chlorinated hydrocarbons such as Nion Carbide, Inc.) can also be substituted.

It will be appreciated that "variant" forms of FEP may also be deposited in this manner. Ta For example, relatively high molecular weight fluids such as DuPont's "Teflon 140" When the olopolymer is cut into small pieces from the rod and vacuum evaporated, we know that it It is assumed that the Am is deposited as different polymers on the reflector film, i.e. , it is probably of low molecular weight and characterized by short chains. , if it were a whole, it would be weakly cross-linked. for example , it is very soft and weakly bonded, so if you rub it with your finger it will wipe away. It will probably end up. Presumably, FEP is separated after such heating in high vacuum. and onto the relatively cool Al1 surface as it condenses and repolymerizes. Moving. On the other hand, if so heated in air, FEP becomes perfluorinated propylene. It is thought that it decomposes into fluorine and tetrafluoroethylene monomer.

Fluoropolymers such as FEP and PTFE contain hydrogen in which some or all of them are fluorine. It has an overall paraffin-like structure. Both are product names ``Teflon'' sold by DuPont. They are very inert (reactive) unaffected by chemicals) under the severe temperatures and humidity for which it was intended. It also appears to be quite easy to bond chemically and mechanically.

"FEP copolymer" is tetrafluoroethylene and hexafluoropropylene. Produced by polymerization of ren. FEP has a crystalline melting point of 290℃; The molecular structure mainly consists of linear chains as shown below.

PTFE is produced by polymerization (free-radically initiated) of tetrafluoroethylene. It is a highly crystalline, fully fluorinated polymer formed by PTFE poly Mer has a crystal melting point of 327℃, and its molecular structure is mainly linear as shown below. It consists of a chain.

+ CFz -cF'F publication F Also, such Am substrates are somewhat active and are not susceptible to polymerization and cross-linking. can be promoted (as in “Z Iegler catalyst”; for example, M , S. Toy, J, Polym, SCi,, Vol. 34, 19 71. D, 273) and relatively to All metal or Au intermediate compounds. Strong chemical bonds can be introduced.

In such cases, the cross-linking of FEP is caused by direct contact with the All film. It is expected that it will be maximum at the roller, and as it moves away from Am in the FEP spacer thickness direction. Therefore, there will be a reduction in (which may or may not be important to obtain).

For our purposes, the parameter sensitivity is defined as the write energy Ew, i.e. the specified minimum necessary to change the reflectivity (or such readout characteristics) enough to give It will be seen that the laser beam is identified.

Here, the intensity and exposure time of the focused writing beam are specified in reflectivity. temperature of the absorber layer 98 to cause the change in temperature. It will be understood that The change can be understood, for example, by the technical speed of sound in the field. The required readout is such that an appropriate contrast SIN ratio is achieved. gives quality etc.: typical of 40-50dB for a bandwidth of about 15MHz See signal-to-noise ratio (peak-to-peak signal to RMS noise).

Laser recording was carried out at 2400 r using equipment of the general type mentioned in connection with FIG. l) done on the finished optical medium in m rotations. helium neon light The laser is again used for recording (wavelength of 0.633 μm). media film 98 The upwardly focused laser beam “spot” is approximately 0.5 μm. The sensitivity of these recordings is very good and is much better than expected from conventional ones such as sample O. You will find that it is better than the one shown below. For example, according to the test 4 , only about 1/2 of the expected write energy is required for acceptable recording. Therefore, the leakage of write heat from the bit position to the spacer is extremely small if FEP is used. It turned out to be a big deal. That is, the FEP is entirely desirable and For example, it clearly helps increase "sensitivity".

Also surprisingly, FEP provides desirable adhesion; In other words, it is stronger than the A1 reflector film, but it overlaps (Te) It appears to be different for absorber films.

This increased sensitivity is due to the aforementioned cross-link changes in the thickness direction of the FEP. This can be explained by the absorber's incompatibility with strong bonding with FEP. can be explained. As mentioned above, if the crosslink is in direct contact with the Am layer, It is maximum at about 1000 yen, decreases (lower density) as it moves away from the ship, and becomes a Te absorber. It turns out that it is weakest where it touches. This difference in cross-linking and joining is acts to reduce heat leakage from the absorber, and when written into the absorber Adapts better to deformation or movement of the bit position. In other words, this "soft material" The "head" spacer is conveniently (deformed) adjacent the absorber 98-a during writing. There appears to be little or no resistance to the formation of This may be partly responsible for the increased sensitivity exhibited by the sample.

Strong bonding of FEP to Ai reflector allows for long-term severe temperature/humidity cycling. This is especially obvious later. In other words, it was found that other spacer layers peeled off, but , this bond withstood. Also, optical "spots" or other aberrations (Am film ) was not caused by such temperature/humidity cycling, but , which occurs when using silica spacers. Silica spacers are too have poor archival stability, such as being porous and absorbing excess moisture; It is clear that there is a tendency to

Additionally, FEP has a relatively low refractive index (somewhat higher than the optimal value) of fused silica. 1.5 to about 1.3).

As the technology of sonic speed would recognize, this could be replaced by a plasma high Precipitation by molecularization or relaxation techniques may also be possible.

Also, the technology of sound velocity is similar to that of other similar “soft pad” polymers by vacuum evaporation. One would think that it might be possible to precipitate it. However, the choice is rather difficult. may be somewhat limited in view of the new requirements. Preferred materials and thicknesses vary. I found it suitable for things. For example, in many cases this spacer ( or the material or thickness of the “soft pad” overcoat as hereinafter described. Different absorber metals can be used without changing the

Sample II (5102 overcoat on e acid body): absorber layer approximately 2000A thick The design of sample ■ is coated with a protective layer of fused silica (ST02). The configuration of the disk is duplicated.

result: As with Sample I, the sensitivity is satisfactory, but some deterioration is expected. It will be done. Also, as TechSonic knows, its 5i02 tends to absorb moisture. This may lead to problematic swelling and deteriorate optical properties. to become

Sample 0 (Si○2 spacer) with some changes as shown and this sample (1) (a partially modified sample 0 is shown here). Sample ■-A, which has an absorber sandwiched between the st02 layers ).

Sample ■ yielded a “low but acceptable” readout, while sample It-A (i.e. , overcoated sample 0) did not give sufficient readout. This is due to sensitivity This is a significant difference between the two countries, and one that has not been fully recognized until now.

This is also due to the improved heat preservation and mechanical flexibility of the soft pad spacer. That is clear.

A similar (but slightly different) improvement would be to use a “soft pad” on top of the absorbent body rather than under it. Seen when a master is placed. Such a "soft pad" is, for example, in this example 1. [-A "hard/soft" overcoat like Example A described later and (Si02 overcoat is replaced with “hard/soft” overcoat) exchange). i.e. placed adjacent (above and/or below) such an absorbent body. It was concluded that such a "soft pad" increases the sensitivity, and in particular it In some cases, "soft pads" replace traditional relatively hard films such as SiC2. Ru.

“Soft pad” as a supercoating on the absorbent body: As mentioned above, such The ``soft pad'' layer is a ``buffer'' supercoated on the absorbent layer. For example, it may be possible to further isolate the absorber layer thermally or mechanically. This is especially true when a similar soft pad is present directly beneath the absorbent material. be. For example, this will further help in saving write energy and Allows freedom to move or deform relative to Pavitt holes while being heated. (e.g., silica, which is considered to have highly constrained hole formation) (compared to Super Coat). If both factors are taken into account, sensitivity should be increased.

It has been found that such a case occurs in the case of sample ① shown later.

The above-mentioned type of ``soft pad'' layer is an absorber (e.g. the above-mentioned Te film). The section head can be used as a buffer supercoat (especially this “soft coat”). (if the “hard” supercoat is then overcoated with a “hard” barrier layer) In the process of discovering the In addition, I learned that it should exhibit the following characteristics (Table I).

Table ■ (Essential requirements for “soft pad” super coat) 1. Optical compatibility: (R/W) Good transparency at λ.

All (or only a small amount) It does not cause resistance, and also does not cause orange beer (tangerine skin) or peeling.

4. Strong bond to (“hard”) overcoat = 5. Under intended environment Stable: (i.e. stable despite changes in temperature and humidity, as well as pollution, etc.): For example, it can withstand operating temperatures without deterioration (in the vicinity of the hole formation position) chemically stable: for example, during curing or in severe temperature and humidity conditions. Does not release solvents or other contaminants even under cling.

6. Softness and compressibility: allow movement/deformation as in #3; It is designed to accommodate bit writing with minimal sensitivity degradation due to server coating. Very thick.

7. Good thermal insulation: For example, low heat dissipation, low specific heat; manufacturing temperature and To withstand temperatures including

By the way, other technologies such as speed of sound use some kind of polymeric strips for such absorbers. I proposed a coating. For example, U.S. Patent No. 4.101.907 For example, it talks about “silicone resin” for general electronics. RTV615 or RTV602 (depending on the curing agent) (cures at air temperature) or Dow Corning's Sylgardl 84, These are proposed for use on titanium. These are preferably sr 02 with an intervening barrier layer" or a composite organic material consisting of.

Sample ■ (FEP on absorber): The absorber film is a layer of FEP (similar to the spacer layer) approximately 950 OA thick. Except that it is covered with SiO□ without supercoat) Sample I disk is duplicated.

result: Similar to sample I, but requires slightly more bit write energy . However, the energy is lower than that of sample ■ (Si02 on absorber). Much smaller.

Sample ■: The substrate disc is a standard aluminum “Winchester” disc ( (used in commercial magnetic recording disks for computer media) The disc of sample ■ is duplicated except for one thing.

result: It is essentially the same as sample ■.

Examples of variable “soft pads”: Engineers should consider using other It will be appreciated that other relatively inert and stable It is long-lasting and does not harden roughly or incompletely or is slightly polymerized and lightly cross-resisted. using bonded “soft” polymers: e.g. modified polytetrafluor chloroethylene, a chlorofluoropolymer that generally similarly decomposes and repolymerizes - or other similar variant fluoropolymers). "Soft pad super coat" The same applies to Other deposition techniques may also be implemented where appropriate; Plasma deposition techniques such as glow discharge (particularly for fluorocarbons) ) or sputtering can be used, especially if chemical decomposition is not complete will be implemented. Engineers may also change the optical absorber, e.g. A highly sensitive thin film that is highly compatible and has a low It may be changed to a thermally conductive material. In addition, the engineer's ability to create such a "soft pad" layer One may think of other similar applications in which this would be advantageous. For example, other similar records as a “separation layer” above and/or below the relatively “hard” coatings such as “Bacote” and markings such as Te film. It can be thought of as a compressible soft intermediate layer between the recording layer, and especially this "soft pad" It bonds well with the hard overcoat and properly bonds with the recording layer. engineer nature would also know similar applications for ODD recording layers in the form of single or double layers. cormorant.

Preferred overcoat embodiment: Example A, Figure 2 (“hard/soft” overcoat 0 -C): Disk Ro in Figure 2 (a very small schematic cross section is shown following Figure 1, (substantially the same as in FIG. 1 except as described) is a preferred embodiment having the characteristics described above. A good example is shown, especially the “soft pad” layer covering the absorbent recording film. A “hard overcoat” applied on top, i.e. a new “hard/soft” overcoat. teaches (schematically) the coating structure O-C (on substrate S). The soft material on the absorber e, which is part of the same type of ODD "triple layer" T-1 given in Compare the hard pad layer f and the hard coat g with Figure 1). See this schematic diagram here and explain.

Everything here (and with respect to all examples) except as specifically described. The materials, methods, and apparatus of You will understand that it is carried out by means of knowledge. In the process of this explanation , some modifications that are useful under the circumstances will also be pointed out.

substrate: Think of the substrate part as an aluminum substrate disk A ( , it can be smoothed 1 or savin to make its surface sufficiently smooth if necessary. processing layer B. Therefore, substrate A is preferably aluminum Alloy ordinary "Winchester" disks, for example computer For high-speed magnetic recording of digital data such as used in memory systems. This is a typical type of disc for manufacturing. The surface of such a disk is Good technical skills (as you know, usually by diamond polishing or other methods) Polished by smoothing. Alternatively, in some cases a suitable glass or may be replaced with a plastic disc.

It can be seen that the subbing layer B is applied to a well-cleaned bare disk surface. There will be.・The ``subbing'' is preferably carried out on the surface of substrate A. Fine irregularities are defined by hole size (e.g., approximately 0.5 μm or less in diameter). ) Made of organic material that smooths into less good ones. As an engineer, I know If the surface is already sufficiently smooth (e.g. highly polished), subbing layer may not be necessary (if a glass disc is used) .

And this substrate is good for use at about 1800 (~1000s) rpm. It is understood that it consists of a 14-inch disc with a smooth surface.

The irradiation (laser) beam with a predetermined energy and wavelength is a laser source (see Figure 1). to the medium Ro. The irradiation beam is In the process, a “bit IZ11 hole” or a hole suitable for the intended readout on the recording layer e is or similar optical “singularity” (e.g., similar to position 98-a in FIG. ) is activated and focused at the "write time" to form the Specifically, for example, i with a diameter of 0.8 μm (i.e., 8000 A) by scanning at 45IIl/sec using a Gaussian beam of omw. (e.g. 0.8 μm2, but not necessarily rectangular) Shape 9 circular.

or any other predetermined form) be able to. By the way, for example, when it comes to record-keeping records, the technical speed of sound is As shown, this requirement is too stringent for traditional means.

Then, at the location where each “bit” (bit) is recorded, an “anti-reflection” barrier is applied. The background is designed to produce “bit marks” suitable for high-contrast succession. will be destroyed. Also, where the appendix wavelength is shifted, the spacer The thickness can be easily varied to produce similar results. This “adjusted” (“3 In the “multilayer” or “dark mirror” structure, the surface reflectance on the absorber e is O'' or other selected value by adjusting the housing thickness and spacer thickness. can do. Here, ``triple layer'' has an absorbent material on one side and the other side. It is understood to consist of a translucent spacer with a reflector on top; The layer thickness is adjusted for ``optical adjustment'' as the technology would know. It will be done.

Therefore, the parameters of the coating are such that the writing beam preferably The coated disc at the intended recording frequency when focused onto the layer It will be appreciated that the selection is made to provide an "anti-reflective" condition to the screen. That's it Regarding this, the above description and “for optical recording” by 3ell and SpOng are used. Anti-reflection structure”, Journalof Quantum l:Iect ronics, Vol,'QE 14. NO, 7゜Refer to JulV1978: Regarding the general prior art, Bartolyni et al. "The Emergence of Systems", IEEE Spectrum, August 1978.1 ), 20, and ``Optical Memory Materials and Methods'', SPI Procee dings.

VOl, 177, ○ptical lnformation S torag e, 1979.1), 56.

Recording part (“dark mirror” type): Add a suitable lower “spacer layer” d and It can be considered as an "absorber layer" e with a reflector layer "C" under the spacer d. Ru. In another aspect of this disclosure, such layers (c, d, e) is preferably a continuous evaporation coat using suitable materials in a single high vacuum chamber. a “soft pattern” given by the A pad '° overcoating f is also applied at the same time.

Instead of this, these impregnations can be applied to any suitable It could also be done by plasma polymerization techniques or other suitable methods. cormorant.

The technical sonic speed is applicable to such a series of similar precipitation steps using a common precipitation equipment. may recognize the advantage of disclosure of materials and techniques that are compatible (e.g., Both the outer layer d and the soft overcoating f consist of similar soft pads. ).

The reflector layer C is preferably a layer of a highly reflective metal such as vapor deposited aluminum as described above. for example, layer C when viewed through layer C in the intended irradiation. is deposited until it is ``just opaque'' (knowledge of the creation of vapor-deposited reflectors). As we know well, if a reflector is too thick, its reflective ability will deteriorate. ). As the technical sound velocity knows, at the wavelength of the intended R/W a sufficiently high Other metals can be used as long as they exhibit reflectance. However, due caution If not, an alternative reflector metal is FEP (also an equivalent spacer material) will not produce any reactivity or bonding effects as shown for Another option is The method is to use dielectric films with mutually high and low indices together with a quarter-wave reflector. .

The spacer layer d is a triple layer formed by combining the reflector layer C and the absorber layer e. ``Reducing the reflectivity of the assembly to zero or other predetermined It is intended to act to reduce the reflectance to a value that the material used is preferably relatively "non-absorbing" and highly absorbent for the intended R/W wavelength. It must be transparent.

The thickness of the spacer d depends on its optical properties and the optical properties of the other layers in this triple layer. It will also depend on the characteristics. Preferably a quarter wavelength thickness of 0.5 to 1.5 will be used. Instead of this, as the technology would know, 1/2 of the multiplex Wavelength thickness may be added (Note: From an optical point of view, a space of thickness Ts = nλr/2 (It will become invisible).

The feature here (mentioned above) is that the spacer material is preferably F"EP, PTFE, or a similar fluoropolymer, preferably a similar fluoropolymer. together with layers C and e (and optionally (along with Hf) is deposited.

Layer e (FIG. 2) is an absorbing film in which the irradiation action "writing energy" is concentrated. . Sample I absorbers may be utilized.

Overcoat part: The ``soft pad'' coating f is preferably of a convenient thickness, e.g. of FEP or similar polymers (e.g., Preferably it is the same material and the same deposition method as spacer layer 0). That's good is prepared and deposited on the absorber e as a FEP coating as described above, and Preferably stacked in the same deposition sequence with the triple layer T-L for convenience. It will be done.

″°When using a 3-layer multilayer, one or more layers deposited as 1/2 wavelength It may be convenient to use f to sense and control the thickness. technology recognizes the speed of sound As expected, the 1/2 wavelength thickness makes the soft overcoating optically The read/write energy applied to the absorber layer must not be reflected. (This would reduce the efficiency of the system).

°゛Soft pad'' super coating f has the intended R/W wavelength ( Not only is it highly transparent to λ(), but it is also sufficiently variable to maximize sensitivity. A relatively non-porous and heat-resistant material that can be shaped and compressed and has a relatively low specific heat. It is essentially insulating. It also firmly bonds to the superimposed barrier layer, However, it is rather weakly bonded to the underlying absorber; for example, the absorber is preferably relatively non-reactive with respect to the bud), and also has L/v , a flash intermediate coating can also be used. It is also chemically safe. (does not emit pollutants in record Ro) , and thermally and mechanically compatible with the adjacent layers (i.e. absorber e and hard coat g). You should get it. Ideally, it would also be convenient and cost-effective to grant. (e.g. using the same deposition method and equipment as layers c, d, e).

FEP and PTFE as described above (vacuum deposited, etc.) are Most if not all of these stringent requirements (such as You will find that it fits perfectly. However, other similar materials (such as For example, similar "weakly polymerized" fluoropolymers) would be suitable.

In addition, such "soft pads" sandwich the absorbent material from both sides. It is recognized that the “thermal and mechanical isolation” provided by this is significant. be understood.

To optimize compatibility and bonding with adjacent coatings (e.g. ``Improve adhesion to the overcoating and/or improve contact with underlying absorbent layers. subsequent treatment of the “soft pad” overcoating (to weaken the bond) is required. It may be. For example, vacuum deposited on the surface of a soft FEP supercoat. Several atomic layers of silicon oxide (SiO2) or Ai, O, are Improves the wettability of hard overcoatings such as radiation-curing acrylic resins. It has been found that this is often preferable for The feature here is that A 1" soft pad" super coating like the one above has a hard super coat on top. provides strong adhesion to the material but relatively weak bond to the underlying absorbent layer I understand that.

The remaining part of the overcoating O-C on the absorber e (i.e. the outer part) is formed with a “hard” overcoating layer (according to the characteristics relevant here) It is preferably made of acrylic resin, which will be described later. This is the outer mechanical protection and (along with pad f) not only to provide the necessary defocusing thickness; Acts as a good vapor barrier and antistatic surface. Preferable for hard overcoat Ω The preparation and associated preferred methods for applying the same are detailed below.

The thickness of layer 9 depends to some extent on the optical system used (e.g. correction of spherical aberration in the objective lens may be relevant). Regarding this example Thicknesses on the order of 100-180 microns have been found to be quite suitable.

Result = (Example A, Figure 2): Examples of “hard/soft” overcoats presented above (e.g., especially the examples below) The acrylic resin shown in ■ is combined with the triple layer of absorbent material in the lower layer as shown in Figure 2. ■ If applied on a ``soft pad'' as in the example above), a surprisingly good Sensitivity (e.g. similar records with a thick 5i0z overcoat over the absorber) (e.g., Table I) It will be seen that it also gives

Of course, the technical speed of sound is described in this example (Example A) rather schematically. You will see that

More detailed characteristics such as materials and precipitation of coatings for °hard and soft pads are mentioned elsewhere (for “hard” see example ■, etc.; for “soft pad” Le1. (see I, etc.).

That is, the "soft pad" overcoat generally described above is In some instances detailed (e.g., with respect to structure, materials, preparation, use, etc.) Sample ■.

(See ``■, etc.'' with their demonstrated results and advantageous features). For example, that Una "soft pad" (FEP or PTFE) is made from ordinary coatings such as fused silica. (e.g., reduces the required write energy and reduces the It provides long and good stability and effectiveness against significant in terms of moisture absorption when combined with a quality overcoat. stomach).

The “hard” overcoat that is formed is consistent with the expected customs of such a protective outer coat. exhibits common properties (e.g. hardness, scratch resistance, non-stick properties) and is easily cleaned. (e.g., dust, oil, fingerprints), λ, and even water vapor and oxygen. It shows low permeability to pollutants such as.

Furthermore, it bonds well to the "soft pad".

Such hard-coated materials can be prepared by spin coating (according to good practice). or by any other suitable technique known to the technology (e.g., spray coating, gutter coating, curtain coating or curtain coating may be performed instead). More details later Radiation-cured acrylic coatings, such as It will be understood that

Other materials for hard/soft overcoatings: if appropriate, other ``hard pad'' and/or ``hard overcoat'' materials are preferred as detailed herein. be used to achieve all or some of the functions shown in the new embodiments; You will understand that the technology is capable of speed of sound. For example, if the The bacote may take the form of a translucent sheet (e.g. on a “soft pad”). (crystal or similar glass-like material overlaid, and vice versa). A place to be again In some cases, the "soft pad" can also act as an adhesive for the hard coat.

Preferred “hard overcoat” materials: Building on the foregoing, we next apply a protective "hard" overcoat as described above. (For example, when covered with an OD disc-shaped “soft paradopa” as shown in Figures 1 and 2) a type of material that is particularly and surprisingly suitable for use as a supercoating state. Subsequently, we apply such “hard coating” materials to OD disks. The present invention describes preferred new and related techniques for application to blocks or similar structures.

Example I: (“Hard” coating on sample ■: am.

application, curing): This example is based on the example of sample Preferred radiation-curable acrylic hard coating mixture for application (on boards) 4 HI It is intended to describe the preparation and properties of IT, and also to describe the preparation and properties of HI IT. It is also intended to describe a general method of applying to a rate and curing it in situ. and a specific specification for subsequently attaching this to a given optical data disc. Details of the preferred method are described (see description related to FIGS. 3 and 4).

By working in air temperature and other normal conditions, the next ``hard overcoat'' poly The polymer mixture H-1 was applied as a ``hard'' protective overcoat approximately 7ml thick. It is intended to be prepared and distributed evenly over a given optical data disc surface. It has the above-mentioned properties of being sprayed and cured. This surface should be treated appropriately. aluminum disc substrate (for example, with a smoothed precoat on top) a triple-layered optical recording matrix overlaid on it, and a Vapor-deposited thin (approximately 9500A thick F) EP or similar "soft paradopa fluoropolymer" "soft paradopa supercopolymer" It can be thought of as consisting of That is, such “variant FEP Polymer” is the substrate of choice here.

Mixture H-1 weight ratio Red to 1 layer i plate - Celrad 1700 (Cel anese) 120105-135 Celrad 3200 (Celane se company) 4035~45TMPTA 160 145~175 2-ethylhexyl acrylate 180 160-200 (2-Eh A) "FC-430" (3M Company) 2.5 2.5 Darocure 1173 5 5 Celrad 1700 is a relatively high molecular weight acrylic acrylate. , facilitated by ultraviolet light (as described below) when properly initiated. It will be seen that it is hardened. This basic prepolymer material has a relatively long Provides the toughness and chemical stability required for cured coatings that extend over a long service life. It is also selected to cure very quickly and conveniently with good clarity. It was chosen because it gives rise to is preferred here because it is generally low cost and easy to use, and furthermore it is Produces a claimed “archival” protective coating as described elsewhere. It is selected because

Ce1rad 3200 has a relatively low molecular weight (1oOO to 2000 column 1 atom) Krylic epoxide, useful for pouring coatings onto substrates. Suitable for low viscosity. It also has scuff resistance, bulk strength and other Increases protective properties and especially resistance to moisture (otherwise suitable Under proper ``humidity test'' conditions, the polymerized coating absorbs moisture. (If it is packed too much, it will expand and become prone to cracking.)

Without such “low molecular weight” diluents (and other low viscosity additives), this preparation will be too viscous and thick to apply (see below for preferred spices). See ral application technique; for example, the mixture must flow through a dispensing nozzle. do not have). Also, cured coatings tend to swell and crack. Probably. The '3200' is relatively inexpensive, compatible with other ingredients, and It is thought that it participates in polymerization.

However, 3200 tends to discolor slightly over time, and may exhibit slight “gel” content (which would be a problem if unfiltered). As such, its concentration should normally be minimized to the extent practicable.

Technical sonic velocity is determined by other similar low viscosity comonomers (or prepolymers; low viscosity diluted It will be appreciated that diluents) may be substituted to adjust the viscosity as appropriate. for example, Other Ce1rad preparations are even lower in molecular weight and also lower in viscosity. It could be replaced with a Ce1rad 1700 in order to But other Common coating polymers are impractical (for example, some silicone resins creates solubility and hardening problems.

Trimethylolpropane triacrylate <TMPTA) in this mixture It is a “low molecular weight” cross-linking agent suitable for use with trimethyl orthotrimethane. Other similar cross-linking agents such as tacrylate could also be substituted. cormorant. As the technical speed of sound is well aware, some such loss linkers are It is usually used to increase the strength etc. of the coating, and it is preferably It is a "low molecular weight" crosslinker.

Omitting TMPTA or Ce1rad (without replacing it with an equivalent) is not acceptable. to reduce viscosity and soften the cured overcoat to allow moisture ingress. tends to cause cracks due to its expansion (for example, (See H-2).

2-ethylhexyl acrylate (2-Eh A) is a supplement to “3200” organic diluent that reduces the flexibility of the final polymer coat (e.g., Added to improve resistance (lower resistance) and adjust viscosity (lower resistance). Technical speed of sound is acrylate (iso-decyl' acrylate) (rare like D It will be appreciated that diluents can be substituted (but the hardness and toughness will be may be slightly affected).

"[)arocure 1173" is such a CUV of such a mixture > Optical initiator suitable for curing. Technical speed of sound is r by Ciba Geigy. r(lacUre#184 or IrgacLlre#651) One of many similar initiators may be substituted.

"F C-430" is a "non-ionic field" for organic polymer coating systems. A ``surfactant'' additive to fluoropolymers characterized as a ``surfactant.'' This shows the functions of the above-mentioned ``Passetting''. It is known to aid in the functioning of It is known as a flow control agent suitable for reducing the surface tension of coatings. So It is very non-reactive and is compatible with water-based or solvent-based systems (and most Recommended as compatible with most polymers). “’　F　C-43 0" is a similar surfactant "FC-431" (also from 3M). diluted by 50% with isopropanol and ethyl acetate. but it has a high polymer weight and is not preferred here) It would also be possible to do so.

In addition, FC-430 is compatible with H- For acrylic mixtures such as No. 1 other It is also possible to substitute surfactants such as

As described later, monomers are mixed in a spiral loop onto the OD disk surface. In the process of adding objects (the spiral bead b on the disc CD in Figure 3) (see related description below), the "bead" is very easily attached. What I found out was somewhat of a surprise. That is, the beads are arranged in a symmetrical manner. remain in place until, for example, the solvent step begins. It only spreads. Alternatively, as in Example M-2 below, if those bits If the code is applied in contact, spreading will occur quickly. In such cases, go Any or all FC-430s will be distributed together. However, the disk It must be difficult to ``maintain the edges'' near the center of the ku.

FC-430 seems to enhance this "setting" effect, and its function has not been achieved until now. was not known for.

, FC-430 is of the type illustrated in Figures 3 and 4, i.e. In the process of rotating a disk and distributing the monomer mixture onto the disk. It is intended to enhance the "setting action" of the lever because its The “beads” applied in this way withstand centrifugal forces so that they do not displace asymmetrically. There must be. As the technology of sound speed will understand, its asymmetrical displacement is This causes uniform coating.

Of course, by using other coating methods the FC-430 additive can be It may no longer be essential and can be omitted (for example, a different surfactants may be used). For example, if the substrate disk is This is the case when the mixture does not continue to rotate while being applied (for example, the mixture flattening (see below).

Most if not all common associated surfactants may be unsuitable . For example, °'Silicone Fluid F-815" by SWS Silicone Co., Ltd. Silicone surfactant, coated to promote smoothness and uniformity It is widely used in However, the spiral shape of the mixture H-1 causes the bead to flow prematurely (insufficient ′′setting action; ゛′ ring-shaped or radially asymmetric thickness). E hecryl-350 (Virginia Chemical Company) was similarly unsatisfactory.

Mixture H-1 was prepared in such a way as to optimize distribution and disc application in all cases. The viscosity is adjusted under the relevant environmental conditions (room temperature, FEP substrate surface, etc.) The final viscosity should be in the range of 100-150 cp.

As presented later, preparations like H-1 (and similar mixtures) It is perfectly acceptable to use any other chemical additives and therefore may be used where appropriate. can add those additives.

Curing: Debris on the (FEP) surface of the disk in an almost completely deoxygenated state. (for example, by pre-cleaning with N2 or similar inert gas as described below). odor application (e.g. via the spiral technique described below; see sample ■). The coating is exposed to ultraviolet light while the disc is slowly rotated. Light cures by exposure for several minutes. This results in a good, well-cured hard part. An overcoating is formed (no supplemental heat is required and completes the polymerization) (no statute of limitations required).

More specifically and preferably, pre-cleaning with nitrogen (e.g. to remove all oxygen) (approximately 30 seconds) and then under nitrogen for approximately 1 to 3 minutes. exposed to UV for a period of time or long enough to cure the coating as required. let Preferably, this is done by rolling the disc slowly (e.g. 1/2 ro This is done while rotating (from m to 2rom), during which a fan shape of approximately 40° to 80' is At each moment it is exposed to UV. The preferred UV beam has two thermal filters , it is not monochromatic but mostly within λ in the range of 0°3-0.4 μm. Yes, the intensity changes with λ (for example, 1/2 minute at 0.366 μm ~5 minutes of irradiation is 10σ'Ill W/cm2). Fewer initiators are used In cases where the Short exposures of high intensity appear to be preferable. Obviously it's "oxygen quench" This is because it prevents

Process optimization: 1. Small air bubbles create “pinholes” or similar scattering sites; This can be removed by vacuum degassing and subsequent careful handling.

2. “Orange beer” texture of the coating is likely to occur. It is a hardening atmosphere can be prevented by removing oxygen in the atmosphere, e.g. Performed by pre-rinsing with nitrogen for 0 seconds and using nitrogen during the curing cycle. . This also significantly reduces curing time.

Where appropriate, care should be taken to ensure adequate stability (over long archival lifetimes). Stress in the material due to poking (e.g. due to volatilization or improper curing due to thermal effects) Other related techniques and/or The technology recognizes that the speed of sound can be substituted by the material and its attendant adjustments. Will.

Radiation curing is preferred over other related methods. For example, "peroxide curing" is generally Complex and difficult to control, it exhibits a short "pot life". difference Additionally, the peroxide curing reaction is exothermic or “outgassing” and easily overheated. The technical speed of sound must recognize that it is difficult to control and dangerous to handle. Dew. For example, for good control of peroxide cure, temperatures must be kept low ( This results in undesirably long curing times. Also, gas is released If the curing proceeds quickly, these gases will not be properly dissipated and may not be as desired. This results in a translucent coating that scatters light.

result: Mixture H-1 is hard when applied onto the disk (FEP surface) and cured. provide a transparent protective coating to meet the requirements mentioned above (e.g. moisture ingress and It prevents the expansion cracks associated with resistant and is also easily cleaned, e.g. by a simple soap wash at room temperature. It will be seen that almost all of the above are satisfied.

Moisture resistance is particularly impressive and impressive, e.g. not 100% impermeable However, this hard coat does not survive after long immersion in water (14 days in one test). However, no expansion crank occurs. Similarly, its hard overcoat degree/humidity cycling (e.g. from room temperature to 140°C and about 40% humidity to 80°C) It has been observed to withstand humidity levels up to 10% for many weeks.

Furthermore, it can be seen that this outer coating exhibits long-term stability. and For example, it can withstand long-term exposure to fairly severe temperature/humidity cycling and Its hard coating does not tend to migrate to other layers of the ODD and degrade the surfactants. or contains low molecular weight components such as photosensitizers or their by-products. Apparently not. This “stability” and its associated toughness are the thought to arise from each cross-linked long chain polymer group It will be done.

In addition, this hard coat is sufficient for FEP "soft pad" as claimed. stick to. If its hard coat and/or “soft pad” are changed, No such adhesion will occur. In such cases, it may be suitable (e.g. ten A “sticky interlayer” (transparent) may be required, but it is preferred. not (e.g. it complicates thickness control).

The concentration of photoinitiator appears to be important. Excess concentration of initiator causing premature curing of the upper surface portion of the coating prior to curing of the lower portion of the coating. It was observed that this resulted in large “wrinkles” in the cured overcoat. It was done. This apparently means that its upper surface hardens and shrinks first, and then relatively still This is because it slips against the uncured, somewhat liquid lower part.

It is also important to control the viscosity and flattening properties (e.g., mixture H-1 keep the viscosity low enough to flatten and high enough to set ). Control of the viscosity of the acrylic prepolymer (mixture H-1) is achieved by applying a coating. This is one key to good ``flattening'' of the surface area. For example, if the viscosity is If too much, the coating bead will “flow” too easily and cannot be properly applied. There really won't be any "set-up". If the viscosity is too high, the bead will Flatten very slowly or not completely flatten. related to this technology in the field of sound velocity and the preparation and use of such acrylic materials. The people involved were distributed “relatively carelessly” over a wide area. You will be surprised at the uniformity of a relatively thick coating. That is, 7ffl i1 or 180μm coating from 3 inches to 4 inches Control on the order of ±0.7 to 7 μm over the span is quite remarkable. (For example, see the 4-inch band Bj in Figure 3, which is a 14-inch band Bj. (extending to a radial point 6 inches from the circumference of disk d).

By the way, the technology sonic in acrylic coatings and other similar coatings such as in the automotive industry as a base for metal overcoatings or some rather unrelated types, such as in photoresist technology. Coatings for applications were also informed. However, these other applications Utilizes relatively “highly viscous materials”°, usually with precise direct control of thickness. It is sprayed with a nozzle to a somewhat thinner thickness in a somewhat crude manner without doing anything. Ru. For similar coatings in the automotive industry, simply smooth and good-looking Only good appearance is admired. However, laser-detected scattering has limited optical properties is much stricter in terms of smoothness and uniformity, and as described later (mixture hl- IA) Example ■ is repeated and the mixture is similarly prepared, except for the modified properties; and similarly applied and cured.

Mixture 1 - HIA Weight Proportion Ratio "Illusion" Ninu Ω-Celrad 1700 80 (120) Celrad 3200 80 (40) TMPTA 16 0 (same) 2-EhA 180 (〃) FC-4302,5(〃) Total 507.5 (〃) result: The viscosity is low (3200 is used more here and 1700 is used less), As in Example I except that the mixture flows and spreads more easily.

uL= Example I is repeated except that a different mixture "H-2" is prepared as shown below. The mixture is similarly prepared and applied and cured.

Mixture H-2 weight ratio comparison (hl-1) Celrad 1700 120 ( 120) (Celrad 3200--excluding) O(40) (TMPTA ...Excluding <) O(160)2ethylhexyl acrylate 185 (180 ) (2-Eh A) “FC-430” 2.5 (2,5) Total 312.5 (507,5) result: The overcoat is ``softer'' and absorbs moisture, causing ``expansion cracks.'' The results were almost the same as in Example 2, except that it was easier to apply.

iL: Same as H-1 except that isodecyl acrylate was replaced with 2-Eh A Another alternative mixture H-3 is prepared and applied and cured.

Mixture H-3 weight percentage Ce1rad 1700 120 Celrad 3'200 40 TMPTA 160 Isodecyl acrylate 180 result: The scratch resistance (surface hardness) is improved, but there are some expansion cracks. It is the same as H-1.

Undesirable preparation: Somewhat surprisingly, similar "irradiation-cured acrylic" mixtures of Therefore, it is not preferable for the purpose in question.

For example, preparations such as mixture H-4 below (intended 0, 4-0.8 μm not sufficiently transparent and translucent (at wavelengths of It is easily discolored.

Mixture H-4: 2- Replacement of “flexible polymer” in Eh’A with “stearyl methacrylate” Mixture H-1 is reproduced except that

result: Some "haze" etc. appears (as above; apparently due to phase separation).

The coating is not sufficiently transparent or translucent.

Mixture H-5: 2-Eh Mixed except that A is replaced with methyl methacrylate (MMA). Compound H-1 is reproduced.

result: Spiralization is not entirely satisfactory (viscosity is clearly too low) . In addition, transparency is impaired and shrinkage due to curing is large.

Ce1rad H except 1700 and 3200 are replaced with acrylic urethane -1.

result: Too much "cloudiness" and swelling, cracking, and separation.

Related acrylic polymers such as the acrylic urethane of mixture H-6 may be cracks and peels under the “humidity test” and/or as a result of moisture absorption It is surprising that it turned out to be cloudy. For example, a modification example consisting of H-1 peels and curls upon curing and sabins after severe temperature/humidity cycling. It was found that the coating could be peeled off and destroyed in small pieces. Also, that It was also surprising that the hard overcoat took in so much moisture (obviously The ``hard'' acrylic coating is more hydrophilic than thought. be).

Additionally, additives of the aforementioned type may cloud the overcoat formed. or discoloration.

For example, when dissolving a solvent resin in a monomer such as 1MA (see H-5), The components that become apparent as a result of "il spots" are prematurely polymerized. ).

Coating method: The following is used to form an external protective overcoat for the OD disk (such as FEP). ) A “hard coating” mixture on the OD disk substratum as in the example above. This is an example of a novel technique for applying compounds. Highly uniform, especially at a thickness of several mils The disc is cured in-situ by irradiation and lasts for a long lifespan as described above. For this reason, it provides protection against the environment mentioned above. These techniques are highly accurate Convenient and economical coating and curing method that allows control of thickness and thickness uniformity. You will recognize that it is a method.

The coating is applied to a highly uniform thickness of approximately 7 ml, but the technical sound velocity It should be recognized that a thickness of up to about 3Qmi1 can be formed satisfactorily. Dew.

``Preparation of the hard coat'' as described above is due to another feature here. For example, a new method for imparting a spiral shape to an OD disk as described below. You will find it perfectly suitable for Such materials are a surprise for distribution. Despite the remarkable simplicity and ease of the above-mentioned remarkable accuracy of thickness uniformity It is suitable for control.

For example, by knowing the requested coating thickness, you can The bead mass per running distance (Om/cm) can be easily converted into a bead value. I can do it.

In that case, the required number of strokes at the spiral spacing predetermined by the flattening mechanism Determine the spiral experimentally. For example, about 3 near band Bb in FIG. ．． Regarding a spiral-shaped band extending from a radius of 5 inches to about 7 inches , under these conditions 20-30 spirals are formed into a very uniform layer of approximately 7 mi + thickness. It was found that it gives a coating. On the other hand, a spiral of 10 or less (produces a highly disturbed thickness uniformity; spirals with much more than 30 Too much. In no case should the spirals overlap.

Therefore, the technical speed of sound is defined as the rotational speed of the disc (for example, here 4-10 rpm) to calculate and control the feed rate of the material. Can be done. This simple technique provides a constant coating density. Wear. That is, a uniform "bead" size ensures a constant delivery rate from the nozzle. I need. As will be appreciated, a constant in the rotational length of the spiral The speed is adjusted to keep bead dimensions and spacing constant despite changes. . Rotation of the disc causes the material to “move” once it has been applied, or It must not be distorted, and of course it must not be “°far” (lzka). Do not drop the disc.

Now, Preparation H-1 is a preferable spiral that forms the surface of the ○D disk in Figure 1. When given in the form, it is stated in 00. This is due to the optical recording structure of the triple layer described above. A further improved layer of ``vacuum deposited FEP'' (or similar understood as an aluminum disc with a similar “soft pad” (polymer surface) Ru.

Generally, the method involves the formation of a predetermined number of spirals on a given (FEP) disk surface. It can be seen that this involves applying the coating material in rows or "beads". Dew. The beads are then spread out into a very smooth and even coating. or “flattened”. This coating is then applied to the “hard” ``cured to form a protective overcoat. Some preferred forms will be described.

Example M-1: New coating method for applying H-1 to FEP substrate Preferred forms are mentioned.

Preferred hard coating mixtures (preferably H-1” above) are uniform and symmetrical. Selected and prepared to be applied to the disc with a spiral row of named "beads" It will be seen that the Then those beads are simultaneously ° ``Solvent flattening'' (predetermined FEP table) by a slowly rotating disk Rapid and highly uniform "flattening" of the bead on the surface). rotation of that disk is just enough to counteract the asymmetric gravity (imaging or asymmetric disk orientation) speed and when the material is softened into a smooth and uniform layer. It should be slow enough not to generate centrifugal forces that would disrupt symmetrical fixation in two directions. With specific reference to Figures 3 and 4, mixture H-1 has a technical speed of sound as known. Injections such as those known to the technical speed of sound that are attached to arm A that can reciprocate (such as a needle) to a means n for dispensing at a predetermined and controlled rate.

The nozzle n deposits the mixture on the surface (FEP) of the disk d at a constant rate. by known means to deliver a constant, carefully controlled, uniform flow st. used and controlled. It is preferably from the periphery of the disc shown in FIG. Start. Thus, as discussed below in connection with FIG. 5, the centrifugal force Fc are opposed, and the force F from the adjacent expanding bead causes the It is opposed to a wide spread displacement. Meanwhile, arm A moves in the radial direction (inner direction) of disk d. It will be seen that the displacement direction (orientation) is continuously and carefully controlled. So Thus, this flow st moves in the radial direction of the disk d while it rotates. Then, a specific spiral SR is drawn. For example, arm A is Near motors are now used in magnetic recording heads while maintaining uniform spacing and dimensions. moved by. You can also change the disc rpm if necessary. (see below). As the technology Sonic would recognize, uniformly sized beads rpIll on disk for distribution.

One or more of three variables: arm speed, and delivery rate. but other variables are held constant.

Therefore, the nozzle n moves to a predetermined position on the disk d while the disk is being rotated. Controllably moved across the radius. And the technology speed of sound will recognize Continuous and uniform spikes of paved sections of uniform spacing, size and shape to ensure Develop the mixture as RAL SR. The mixture is formed into such a spiral (and For example, to form 25 beads spanning a 3.5 inch radial band B) well known pressure orifice control means provided for dispensing at a predetermined rate to (not detailed) to the nozzle n.

The technical sound velocity is shown in the cross-sectional partial schematic diagram of Figure 4 showing a row of three adjacent beads. You will recognize the bead distribution formed as shown in the figure. Those columns are given gap! +! separated by + (note: they cannot touch or overlap) ), their cross-sectional shape, nine dimensions, and quantities are well known in the art. By appropriate calculations made in advance, such as. ) is used while being kept at a predetermined value, Uniform planarization results in a protective overcoat of the thickness applied over disk d. (See external coating 9 in Figure 2).

For example, using mixture H-1 at normal '° (room) temperature and the Using a polymerized FEP substrate surface such as evenly spaced across a approximately 3.5 inch wide disc band starting from a radius of 20 to 30 spiral sections (assuming proper flattening and hardening) It was found to yield a highly uniform coating of approximately 7n11 thickness. On the other hand, 1 Zero or fewer rows reduce the coating thickness so much that it becomes unusable. Made it uniform. Also, if the minimum gap U is not maintained and especially if the column SR It was virtually impossible to achieve precise thickness control for overlapping fittings ( Its control is ±0.7 to 7 microns for 7m:1 coating; onto such large substrates using simple coating equipment such as (The uniformity is quite surprising for this material.)

If the distribution rate is kept constant, rotation of the disc to form a uniform bead (e.g. 4-5 rpm at the innermost radius) In the case of a (gives a constant bead volume). To maintain uniform and evenly spaced rows, The movement of the nozzle n in the radial direction by A is also well known in the art (disk center (according to its distance from). Instead of this, the technical speed of sound is As we know, we can change the distribution ratio to form the same uniform spiral. It may be made into

The rotation of the disc and the movement of the arm detailed form uniformly spaced beads. (which are arranged radially at a predetermined distance U, e.g. Preferably, 25 beads are lined up over a radial band of 3.5 inches. ru〉. The separation distance Qg can be varied within the following limits. But I wonder The “beads” should not “overlap” even if The “solvent flattening agent causes the beads to flow and unite to form the target thickness uniformity.” Don't go too far away. Also, each bead should be appropriately “raised”. (at its height) to obtain sufficient contact (area) with the substrate to allow (i.e. to obtain a good wZh ratio) do not have. Next, if this spiral bead is sufficiently applied, the flow st will end. the disk rotation is set for ``solvent flattening''. (preferably about 1-2 rl1m).

As mentioned above, mixtures such as H-1 are attractive in this regard. why If so, it maintains a given uniform and symmetrical form and is sufficiently “set up”. This is because that. The slope of the bead relative to the disk surface is relatively steep. ” (smaller “wetting angle” than normal).

That is, the bead is brought into contact with solvent vapor for flattening and its wetting angle is steepened. Figure 4. and its symmetry as shown in FIG.

As previously mentioned, the FC-430 additive is suitable for use on such (FEP) substrates. to control and improve bead wetting and “set-up” (of such mixtures). selected and designed for

Step #3: Solvent planarization: The spiral array of beads is then exposed to a uniform "mist" of solvent vapor, This causes the surface of the bead and the interacting (FEP) substrate to suddenly ``wet'' quickly (by condensation of solvent, preferably all beads and resulting in a relatively continuous thin film condensed across the substrate). stop instantly lowers the wet surface tension, softening the bead and rapidly flattening it. ” (i.e., immediately expands, is held down by gravity, and becomes symmetrical) (This results in a uniform coating that can be flattened and polished). Very precise thickness control be recognized as important. Therefore, if so coated di The surface of the disk d is not in a perfectly horizontal plane and the gravity acting on the bead is not perfectly symmetrical. If not, the disk d is sufficient to counteract any non-uniformity or asymmetry. (as the technology in the field of sound speed will recognize) , also counteracts "vibration" of the disk surface during solvent planarization and things like that).

Therefore, disk d is preferably rotated once solvent planarization begins (e.g. In this case, 1 to 2 ROM). And the bead flow is relatively perfect coated. This will give uniformity of the results. However, this rotation produces a flow due to centrifugal force. It's not fast.

A disk d (on which a spiral bead is applied) is applied to the specified solvent vapor. When exposing the disc to a hood, place the disc in a hood and apply steam at a predetermined pressure and concentration. can be introduced (or by other methods as the technology will recognize) ).

Therefore, for such bead softening and solvent flattening, the solvent is in column b (bead) and the FEP substray that interacts with it are relatively uniform and continuous. The beads and substrate condense very quickly as a film The solvent and its conditions must be selected to produce "wetting". and, The applied bead covers the adjacent FEP surface (pushed by gravity). the solvent is condensed enough to collapse and flow (the solvent is promotes good 'wetting', in this case it is the wetting of mixture H-1 on the FEP. ).

Here, for simplicity, we assume that acetone is used as the solvent, and further It quickly moves over the bead and across the FEP substrate it interacts with. Steam or saturation on that bead under conditions (temperature/pressure environment) that allow it to condense Assume that it is simply poured out as a "mist".

For example, here all these surfaces suddenly become "shiny", but droplets and large No puddles are shown. i.e. “droplets” or large condensation on the bead or disk. It is kept low enough not to cause significant puddles and increase volatility if this occurs. Must be. This exposure instantly softens the ``beads'' and quickly removes them. It will be enough to flush each other (actually instantaneously in this case).

The volatility of the solvent is preferably high enough so that once the bead When the (FEP) disk surface is sufficiently wetted, the solvent evaporates. Qi will quickly evaporate and dissipate (or be removed, e.g. by pumping). (leaved). Therefore, little or no solvent remains during planarization. preferable.

The results of such "solvent planarization" are surprising.

Adjacent beads are observed to flow together in a "flattening" operation, which Forms surprisingly quickly and with remarkable coating uniformity.

Solvent properties, some changes: Solvents should be selected based on the working temperature, substrate surface, and chemistry of the mixture. At this temperature, the substance softens the mixture and produces easy flow. i.e. the solvent is specific for these conditions and may require adjustment if conditions change (e.g., different coatings). (on mixtures or different substrate surfaces).

One advantage of using a solvent like acetone here is that it can be used before curing begins. This means that little or no solvent remains without evaporation. be. In other methods, copolymerization with coating mixture H-1 can be expected. Solvents must be substituted (methyl acrylate solvents cannot be copolymerized as such). ), and does not in any way inhibit polymerization or have any properties that can be considered. Non-affecting solvents must be used.

Alternatively, as those skilled in the art would recognize, Polystyrene monomer can be used as a planarizing solvent if it has sufficient volatility. or ethyl acetate, methylene chloride or methyl ethyl ketone ( A solvent such as MEK) can be used.

Although styrene is expected to copolymerize at least to some extent with the acrylic mixture, , other things are not like that, so they must be volatilized sufficiently.

Therefore, changing the properties or chemistry of the disk surface is difficult, e.g. (using a ``flash coating'' of thin oxide on FEP), generally ``wetting'' changes its ``characteristics'' and causes some change in its ``flattening effect'' (often with different (requires solvent vapor). For example, A negative 20. on FEP. Or SiOa RuiwaS: A thin film of O2 seems to promote wetting, especially for the previously mentioned Significant when using setone solvent vapor.

Also, when using such "solvent planarization", it is necessary to A mixture that is not very wettable, for example H-1), is prepared. otherwise , enough that the mixture maintains its shape while being applied into a spiral. It will not "set up" as well on the substrate. For example, that The mixture is centrifuged before contacting the solvent as the disk is rotated during spiral formation. It will collapse asymmetrically due to the force. FC-430'like "surfactant" Additives that promote "set-up" can of course help in this regard. For various reasons, the bead must have sufficient contact area with the substrate. .

Controlling the viscosity of the mixture is very important to obtain good distribution and uniform fixation. I understand. For example, adding a more volatile monomer such as MMA to mixture H-1 In addition, excessive wetting of the FEP substrate can result in very condensation between bead b. tends to shrink and therefore causes improper pas- sage set-up, resulting in premature beads. cause "fixation" of

Conversely, care must be taken to avoid creating "drop-outs" or "pinholes." stomach. They are voids where little or no solvent condenses; (Note: As the ambient temperature rises, it will become wetter.) The voids seem to get bigger, which is probably due to the solvent evaporating too quickly. ).

Of course, if the mixture can be immediately ``self-planarized,'' There would be no need to remove the FC to “set up” the mixture. -430 (see IVI-2 below) ).

Step 4: (hardening): If it is completely flattened and the coating is evenly distributed on the surface of the disk d, then it Leave intact (otherwise processed) and hardened. Then, the rotation of the disk is stopped and the disk is placed in curing conditions. It is preferably done so that the uniformity of the coating is not compromised. or the introduction of contaminants (e.g. settling of dust on the sticky surface). to avoid moving the disk from the “solvent flattening” station. be called.

Therefore, UV curing is performed at the solvent planarization station. That is, Once the material is spread evenly over the surface of the disc, the coating will cure properly. in an inert atmosphere (e.g. to expel all oxygen) until it becomes “hard”. It is photocured by exposure to ultraviolet light (N2 spray). 0.3~0 ．． LIV of 4 μm (for example, 100 mW/cm2 at 0.366 μm A total exposure of about 5 to 20 seconds to is found to be sufficient.

Alternatively, other similar curing methods (e.g. electron beam or IR irradiation) may also be used. In some cases, appropriate adjustments (e.g. adjustment of photoinitiator concentration) may be made. It can be used by doing.

result: As previously mentioned, thickness uniformity (3.5 inches for a nominal 7ml coating) (on the order of ±0.7-7 μm over the band) is quite remarkable. , especially in terms of the simplicity of its application equipment and the type of coating mixture used. Therefore, it is worth paying attention to. As mentioned above, curing time and temperature depend on other processing conditions. It's just as convenient.

If the temperature (heat) becomes considerably high during this (spiral train b) solvent flattening The fact that the flow did not increase in velocity or flatten faster is somewhat It was surprising. Rather, the rows are more bead raised and spread out. In fact, the width seemed to be narrowing. The cause is not known for sure, but the solvent This is thought to be because the acetone vapor became too hot to properly condense and wet the surface. adjacent to cause direct “self-planarization” without the need to use a solvent planarization step. Examples where abutting beads are actually placed in contact, except as detailed below. Example IV11 is repeated.

More specifically, the hard coating mixture (e.g. H-1) is again prepared. (FC-430 may not be necessary; see above), and continuous They are distributed in a typical spiral arrangement, but the gap U between the beads (Fig. 4) is almost reduced to almost zero. This is the idealized sequential pattern in Figure 5. , with the first bead b-1 shown in dashed lines. Bee The line b-1 actually collapses immediately and becomes flat (the solid line b-1), and therefore the neighboring When bead b-2 is placed it will come into contact with b-1 (which expanded slightly) cormorant. The "spreading motion" of m-1 tends to push b-2 toward the center of the disk. (See the spreading force Fs.) However, each successive bead will self-spread in such a way. Since the disk is pressed by ). The method of drawing a spiral from the outside to the inside is the centrifugal force caused by the rotation of the disk. component (FC) is intended to oppose the spreading force F (arrow in Fig. 5). ). Flattening solvent in the pattern of the distributed mixture (spiral-like columns) temperature/substrate to cause “self-flattening” without having to provide It is assumed that the temperature conditions will result in an appropriate reduction in the viscosity of the mixture. Technology speed of sound will recognize. Slower disk rotation (or no rotation) or FC -430 for some other applications, such as the replacement of other surfactants. Separation is also recommended. Of course, the surface of disk d must be maintained in a horizontal plane. The problem will still exist. Therefore, “vibration” or uneven “weight” Appropriate disk rotation is recommended to counteract the force.

Therefore, by using a ``self-flattening'' bead, it is possible to A simple “raw step” coating sequence that eliminates the necessary solvent planarization performance is realized. Its curing is carried out as in the case of IVI-1, and its formation The applied coating will be essentially the same as for M-1 (in fact, some (excellent uniformity in all cases).

Of course, as in the previous case, the flow rate (rf, from nozzle n onto the disc), di Three 7 actors: screen ROM (w, t), and arm speed (Ve) In each case, the change in bead position (i.e., each bead segment Distribute beads of uniform size and shape regardless of the radial position of the bead (db) It will be adjusted accordingly.

A particular example of this is shown in FIGS. 6-8.

Figure 6 shows the disc rpm (w,) and the aperture at a constant flow rate (R). By increasing the speed (c) relatively uniformly (e.g. starting from the periphery of the disc) (approximately 1:2), the final coating thickness t. is the radius of the disk It depicts (very schematically) how things change in this direction. This “self-fixation” It can be seen that the effect complicates the process of uniform coating.

To correct this, increase the rpm continuously as shown in Figures 7 and 8. Increase (ΔW ma α or = φ radius) and accelerate the arm somewhat (ayu = Δ■ /l), then some deceleration, and finally acceleration (a knee φ' radius) We propose a coating in a corrected mode. disc rpm yes In any case it will preferably be minimized. That is, generally it is rpl[l such that these spirals can just cause "mutual flow". .

Until now, other methods of imparting defocusing overcoat to the technical sound velocity have been proposed. It has been shown. °For example, in U.S. Pat. No. 4.340.959 to 1eVin T, 0.05-1° is shown, and in that coating technique the disc is Must be placed as a mold and application by “spinning” methods is excluded. (See references cited by l evin).

In Figure 7, when the flow velocity is kept constant, the changes in W and ■ are shown. Displayed as a function of bead position (db). In Figure 8, those The values are depicted as somewhat idealized. The speed change (acceleration) of the slider is somewhat surprising. It turned out to be something like this. That is, the speed should be gradually increased at first. In Figure 8, the curve ■ is at position a-+b), then rapidly falls (position b-+c), and reaches its maximum. It is later put into continuous increasing mode (exponential increase; see position c-+d, etc.). So This occurs because the bead thickness first becomes lighter and then it increases, so that some kind of equilibrium is reached. It is necessary to decelerate the slider arm until it reaches (position C) (position b → C), and then Therefore, continuous acceleration is required in response to the decrease in the arc of the bead (c-+d).

Example M-3: (3i0z flash on FEP) Also, what kind of coating No matter which adhesion technique is used, it may be necessary to It would be advisable to pre-treat the substrate as indicated. for example, Example M-1 above (H-1 applied spirally onto FEP and flattened with solvent) ) or its modifications, the hydrophilicity of the (FEP) substrate It would be desirable to increase the wettability of the substrate to the substrate. in such case , 3i0z very light on FEP before applying H-1 or similar bead. 'Flash' coating (e.g. Si02 on layer f in Figure 2) I found out that it would be convenient if I applied it.

Example M-4: (Similar to M-1 in which FEP sandwiched the absorber in a sandwich-like manner) : Both FEP layers are supported by being deposited in a vacuum chamber common to the triple layer. sample ■ is reproduced. FEP “spacer” is n/l y/4 optical thickness On the other hand, the FEP "soft pad" supercoat is about 1-2 μm thick. .

(eg, preferably on the order of 100 times the thickness of the absorber film). The “1” The "hard" overcoat is thick enough to defocus surface dust, etc. and is carried out as in preferred method M-2 above.

Different uses: Such “hard” coatings are similar to modified “soft pad” coatings. Technics recognizes that it can be prepared for application to other somewhat textured surfaces. Probably. Also, those whose substrate surfaces are fundamentally different (for example, G Even in the case of silicone elastomer (such as RTV made by Company E), The “non-conforming” substrate is coated with a “hard” overcoat as described above. Technological Speed recognizes that a pre-coat or other pre-treatment may be applied to accommodate the you will understand. For example, in plastic coating and processing technology. , for processing a wide variety of polymeric substrates to enhance their “wettability” Various methods are known. For example, by halogens or active oxidizing agents. Lightly oxidize or burnt with a propane torch or exposed to electrical discharge. or even inserting a pre-coat such as SiO2 as described above. It is. They can be used where appropriate and can be combined with the present invention. Both are possible.

The preferred embodiments described herein are merely illustrative, and the present invention is not limited to its configuration or use. It is understood that many modifications and changes may be made in the application without departing from the spirit of the invention. It will be.

For example, “soft pad” coatings similar to those disclosed herein Substrates with other substrates and/or other supercoatings It could also be applied to protect traits (e.g. a given “isolation” ”).The present invention also relates to other similar recording materials. It can be used to provide a "parasol isolation layer".

Additionally, a “hard outer coating” similar to that taught here could of course be used. used to cover and protect other substrates for similar purposes (The above-mentioned "spiral" coating method can be applied by appropriate adjustment) Other materials can also be used. Additionally, such coating structures can also be formed by other methods if appropriate. For example, quality coating” substrate (for example, 7mi + acrylate loose Utajo) A soft pad tube is deposited on the soft pad, an absorbent material is deposited on the soft pad, and then an absorbent material is deposited on the soft pad. Deposit as many spacers/reflectors as necessary on the absorber and finally Adhesive is applied onto a ``Chester disk'' or similar ``carrier'' and pressed together. This is a method that allows

Further modifications of the invention are possible. For example, the means and methods disclosed herein are Recording tapes or floppy disks coated with “soft pads” or similar It can also be applied to objects. Furthermore, the present invention provides that data is recorded using IR exposure. other forms of recording and/or recording systems such as recording and/or reproduction; Adapted to provide a similar protective external coating for media used in It can be used.

The above examples of possible variations of the invention are merely illustrative. Therefore, the present invention shall cover all matters arising within the scope of the invention as defined by the appended claims. It should be considered to include all possible modifications and changes.

FIG, 6° FIQ7 1) Indecency investigation report Continuation of page 1 ■Int, CI,' Identification code Internal reference number o Originator Polling, No Man L Amerilou 0 shots: Rancourt, James D. Amelie Yau Power United States, 95401 California, Sashita Rosa Loroad, 276 9 Power United States, 95405 California, Sashita Rosa Gid Drive , 129

Claims (1)

[Claims] 1. Apply a medium to high viscosity coating to the disc substrate for non-stick In a way that consistently produces precise thickness uniformity, preparing a coating mixture and applying a circular or sputtered coating onto the disk surface; To form one or several arch-shaped bead segments extending in an irradial shape. applying the mixture in a predetermined flow to the disk surface; The mixture is prepared and applied to form a flattened coating. A method for applying a coating characterized in that: 2. The mixture is prepared to be "self-flattening" so that the bead segment Claim 1, characterized in that the components are distributed adjacent to or substantially in contact with each other. The method described in Section 1. 3. The mixture not only exhibits a predetermined viscosity suitable for distribution, but also to show the wetting properties of a given chicken trobi (formerly known as xotropy) and bead set and distributed through the nozzle, thereby distributing the distributed beads. ``Set-up'' on the disk surface for a sufficient period of time to flatten the component. 2. The method according to claim 1, wherein: 4. The mixture is prepared to be "self-flattening" and the bead segments are distributed adjacent to or substantially in contact with each other. The method described in Section 3. 5. After the bead forming step, wetting the disk surface with the mixture This is followed by the application of a relatively uniform and continuous “solvent fog” of a given solvent suitable for , this mist wets the applied bead and intervening disk surface relatively continuously. The solvent also initiates and promotes the planarization. The method according to claim 3, characterized in that the method is selected and applied so as to . 6. The beads are arranged in a series of adjacent beads separated by a predetermined bead spacing suitable for the planarization operation. It is characterized by being presented as one continuous spiral with intersecting segments. The method according to claim 1. 7. The mixture not only exhibits a predetermined viscosity suitable for distribution but also and also exhibit predetermined thixotropic and wetting characteristics for the disc surface. prepared and distributed through a nozzle, thereby flattening the bead. ``setup'' on the disk surface for a sufficient period of time. The method according to claim 6. 8. The mixture provides not only the "wettability" but also the "set-up" effect. Formulated to contain a specific “setting surfactant” to 8. A method according to claim 7, characterized in that: 9. The mixture comprises at least one acrylate and at least one related including a viscosity controlling diluent and a compatible cross-linking component, further adding ” and one or more compatible fields suitable for providing said “setup”. 8. The method of claim 7, further comprising a surface-active material. 10. The disk surface is made of a predetermined polymer, and the bead and this polymer It not only provides the wettability of the surface of the matrix but also ``top-sets'' the bead. sea urchin, and a corresponding surfactant is included in the claim. The method described in Scope Item 9. 11. The solvent planarization is acetone, ethyl acetate. Very thin continuous filaments of solvents such as methylene chloride, or methyl ethyl ketone The method according to claim 10, characterized in that the method is achieved by adding a lume. . 12. A product produced by the method according to claim 1. 13. A product obtained by the method according to claim 2. 14. A product produced by the method according to claim 3. 15. A product produced by the method according to claim 10. 16. The nozzle means is adapted to dispense the mixture at a predetermined dispensing rate. and controlled so that said nozzle means moves in a radial direction of said disk. mounted on adapted and controlled arm means, said disc being non-paired; rotated at will at a predetermined rpm from O suitable to counteract typical bead flattening. 4. The method according to claim 3, characterized in that: 17. The dispensing speed, the moving speed, and the rpm of the disk are at a predetermined uniformity. for distributing said segments of uniform size and shape at predetermined constant segment intervals; 17. A method as claimed in claim 16, characterized in that the steps are mutually controlled. 18. said segments are distributed adjacently or nearly touching, thereby Self-flattening begins and its distribution counteracts inward pressure by adjacent segments. Claim 17, characterized in that it is advanced "from outside to inside" for erasing. the method of. 19. For a constant delivery rate, the rpm of the disk depends on the radial position of the segment. The arm speed is also controllably varied by being increased continuously as a function of the position. , thereby improving the uniformity of the final coating thickness. The method according to claim 18.