Disk alignment apparatus and method for patterned media production

An apparatus and method for aligning a disk with an imprinting surface are described. In one embodiment, the apparatus has a die which includes an air-bearing mandrel having a tapered nose to engage an ID of the disk, a circular imprinting surface having a centerline concentric with the air-bearing mandrel, and an air-bearing cavity to position the disk. The axial movement of the top die towards the bottom die guides the ID of the disk into coincident alignment with the centerline of the top die.

FIELD OF THE INVENTION

This invention relates to the field of disk drives, and more specifically, aligning and imprinting of disks for use in disk drive systems.

BACKGROUND OF THE INVENTION

A disk drive system typically consists of one or more magnetic recording disks and control mechanisms for storing data within approximately circular tracks on a disk. A disk is composed of a substrate and one or more layers deposited on the substrate. In most systems, an aluminum substrate is used. However, alternative substrate materials such as glass have various performance benefits such that it may be desirable to use a glass substrate.

To produce a disk substrate from a blank sheet of metal-based material such as aluminum or aluminum magnesium, the sheet may be stamped to generate a disk substrate having an inner diameter (ID) and an outer diameter (OD). After stamping the ID and OD, the disk-shaped substrate may be heat treated to remove stresses and then polished. The disk may then be coated with a polymer overcoat.

The trend in the design of magnetic hard disk drives is to increase the recording density of a disk drive system. Recording density is a measure of the amount of data that may be stored in a given area of disk. One method for increasing recording densities is to pattern the surface of the disk to form discrete tracks, referred to as discrete track recording (DTR). DTR disks typically have a series of concentric raised zones (a.k.a., lands, elevations, etc.) storing data and recessed zones (a.k.a., troughs, valleys, grooves, etc.) that may store servo information. The recessed zones separate the raised zones to inhibit or prevent the unintended storage of data in the raised zones.

One method of producing DTR magnetic recoding disks is through the use of a pre-embossed rigid forming tool (a.k.a., stamper, embosser, etc.). An inverse of the surface pattern is generated on the stamper, which is directly imprinted on the surface(s) of a disk substrate. Thin film magnetic recording layers are then sputtered over the patterned surface of the substrate to produce the DTR media having a continuous magnetic layer extending over both the raised zones and the recessed zones. To imprint tracks on a data storage disk substrate, an imprinting template may be attached to a flexible support, whose curvature can be altered by applying hydrostatic pressure. By suitably varying the pressure, the imprinting surface can be brought into contact with the disk substrate.

An imprinted disk may not be viable if the imprinting surface is not concentrically aligned with the disk substrate. Imprinted tracks that have excessive offset from a centerline of the disk substrate may not operate properly when read by a disk drive head. This requirement is particularly important in disks used in hard disk drives in which tracks may need to be imprinted on both sides. As such, imprinting a disk requires an alignment step, in which a centerline of the disk is aligned with a centerline of the imprinting surface, before the disk substrate is actually imprinted.

Current alignment methods typically require the use of high precision actuators or robotics. For example, the high precision actuators would first determine a centerline for the disk substrate and align it with a centerline of the imprinting surface. The use of such high precision actuators and robotics are expensive, with high maintenance costs, inconsistent accuracy and reliability, and slow cycle times. The high precision actuators and robotics are also significant pieces of machinery, requiring large amounts of floor space.

SUMMARY OF THE INVENTION

An apparatus and method for passively aligning a disk with an imprinting surface are described. In one embodiment, the apparatus has a top die that includes an air-bearing mandrel having a tapered nose to engage an ID of the disk, a circular imprinting surface having a centerline concentric with the air-bearing mandrel, and a bottom die having an air-bearing cavity to constrain the disk. The axial movement of the top die towards the bottom die guides the ID of the disk into coincident alignment with the centerline of the top die.

DETAILED DESCRIPTION

In the following description, numerous specific details are set forth such as examples of specific, components, processes, etc. in order to provide a thorough understanding of various embodiment of the present invention. It will be apparent, however, to one skilled in the art that these specific details need not be employed to practice various embodiments of the present invention. In other instances, well known components or methods have not been described in detail in order to avoid unnecessarily obscuring various embodiments of the present invention.

It should be noted that the apparatus and methods discussed herein may be used with various types of disks. In one embodiment, for example, the apparatus and methods discusses herein may be used with a magnetic recording disk. Alternatively, the apparatus and methods discussed herein may be used with other types of digital recording disks, for example, a compact disk (CD), a digital video disk (DVD), and a magneto-optical disk.

In one embodiment, the apparatus and method described herein may be implemented with an aluminum substrate. It should be noted that the description of the apparatus and method in relation to aluminum substrates is only for illustrative purposes and is not meant to be limited only to the alignment and imprinting aluminum or metal-based substrates. In an alternative embodiment, other substrate materials including glass substrates may be used, for example, a silica containing glass such as borosilicate glass and aluminosilicate glass. Other substrate materials including polymers and ceramics may also be used.

An apparatus and methods for using the apparatus to align a disk for patterned media production are described herein. In one embodiment, the disk is passively aligned with an imprinting surface, thereby eliminating the need for high precision actuators and alignment tools. In another embodiment, the apparatus includes a very high-precision die set that establishes the inherent side-to-side alignment and repeatability of the patterned media. An air-bearing supported alignment mandrel resides in the top die, as well as an imprinting surface coupled to a circular elastomer pad that accommodates thickness variations of a disk substrate. A centerline for the air-bearing mandrel matches a centerline for the imprinting surface. The bottom die contains an annular air “manifold” located substantially near the ID of a cavity to constrain the disk before alignment. All of the die body elements and mandrel are of circular configuration and like materials, thus minimizing thermal distortion and maintaining critical clearances at air-bearing surfaces. The alignment process is passive because the air-bearing mandrel freely guides a centerline of the disk into alignment with a centerline of the imprinting surface.

In an alternative embodiment, a precision die set establishes a fundamental side-to-side alignment and repeatability of the patterned media. Air-bearings are used in multiple places to attain precise, total system alignment. Specifically, air-bearing supported alignment mandrels are disposed in the top and bottom die portions. The air-bearing alignment mandrels have intermeshing, tapered nose portions. The bottom die rests in a double air-bearing nest with one planar surface and one spherical surface. A circular elastomer pad to accommodate substrate thickness variations may also be disposed central to the air-bearing mandrels adjacent to the substrate. Most of the die body elements and mandrel are of circular configuration and like materials, thus minimizing thermal distortion and maintaining critical clearances at air-bearing surfaces.

In another embodiment, an air-bearing supported alignment mandrel resides in the bottom die. Hermetically sealed die foils are welded over shallow cavities on top and bottom die pieces. Most of the die body elements and mandrel are of circular configuration and like materials, thus minimizing thermal distortion and maintaining critical clearances at air-bearing surfaces.

In another alternative embodiment, the patterned foils are aligned via pico-actuators and held in place. An air-bearing supported alignment mandrel resides in the bottom die to receive the disk. Most of the die body elements and mandrel are of circular configuration and like materials, thus minimizing thermal distortion and maintaining critical clearances at air-bearing surfaces.

Referring toFIG. 1, a cross-sectional view of one embodiment of a disk alignment apparatus100for patterned media production is shown. In one embodiment, the apparatus100passively aligns and imprints a disk180or similar substrate. Disk180may be a magnetic disk for data storage (e.g., for use in a hard disk drive) or alternatively, disk180may be an optical-type disk. Apparatus100has top die130and bottom die135portions. Support portions105,110and columns115,120stabilize top die portion130and bottom die portion135.

Top die130includes air-bearing mandrel140disposed near a middle portion of top die130, and has a tapered nose oriented to face bottom die135. Air-bearing mandrel is supported by air manifold172that enables air-bearing mandrel passive axial movement. Air-bearing mandrel140has a diameter sized to engage an ID182of disk180. Top die130also has first imprinting surface160disposed around air-bearing mandrel140. In one embodiment, first imprinting surface160may be adjacent or coupled to first elastomer pad161to accommodate variations in thickness of disk180. First imprinting surface160may also be a foil having the track features to be pressed on a disk. In one embodiment, first imprinting surface160has a circular shape to match disk180. A centerline for air-bearing mandrel140is aligned with a centerline192for first imprinting surface160.

Bottom die135has a circular cavity165to contain an elastomeric annulus. Bottom die135also includes an annular air manifold170disposed substantially within cavity165to position disk180. In one embodiment, disk180is positioned by floating disk180within cavity165. Bottom die135also has a cylindrical opening150sized to receive tapered nose145of air-bearing mandrel140. Bottom die135has second imprinting surface162adjacent to second elastomer pad163, with a centerline194aligned with the centerline192of first imprinting surface160of air-bearing mandrel140. In one embodiment, the die body elements including air-bearing mandrel140are of circular configuration and like materials, thus minimizing thermal distortion and maintaining critical clearances at the air-bearing surfaces. Examples of materials that may be used for the die body elements include, but are not limited to tool steels such D2, M2, and 440-C.

In one embodiment of a method to align and imprint disk180with apparatus100, disk180may first be placed over circular cavity165(which may contain an elastomer and heating element) by any number of automated methods. For example, in one embodiment, a robot or a pick and place (“P&P”) device places disk180in circular cavity165. Annular air slot170disposed near ID182positions disk180by floating disk180a few thousands of an inch above lower die cavity165. In an alternative embodiment, a second imprinting surface162adjacent second elastomer pad163may be disposed on disk cavity165and oriented to face a bottom side of disk180. Disk180is initially axially constrained by shallow OD cavity walls that are a few thousands of an inch greater than the nominal diameter of the disk180.

Apparatus100closes by top die130descending axially towards lower die135. Upon die assembly100closure, tapered nose145of air-bearing mandrel140freely guides the floating disk ID182into coincident alignment with the centerline190of the top die130. Because the air-bearing mandrel140moves freely on its own axis via air-bearing support, with its own weight directing a small downward force, air-bearing mandrel140remains in controlling contact with disk180as the centerline190of air-bearing mandrel140is aligned with the centerline196of disk180(and vice versa). Very low volumes of clean dry air (“CDA”) may be necessary to support the disk180and air-bearing mandrel140.

With the centerline196of disk180aligned with the centerline192of air-bearing mandrel140and first imprinting surface160, top die130continues to descent towards lower die portion135. Tapered nose145of air-bearing mandrel140lowers toward bottom die135, and first imprinting surface160becomes in contact with the disk surface to imprint disk180. Depending on whether an imprinting surface is disposed on top die130, bottom die135, or both (e.g., first and second imprinting surfaces160,162), either one or both sides of disk180may be imprinted. This method provides precise side-to-side alignment and repeatability for the imprinting of disk180. Apparatus100passively aligns disk180with imprinting surfaces eliminating the need for precision actuators or similar machinery. As such, the use of apparatus100provides greater reliability, reduced operating costs and maintenance, improved accuracy and repeatability, and faster cycle times. In one embodiment, apparatus100attains a disk-to-die alignment of +/−5 microns or better.

FIG. 2illustrates a cross-sectional view of another embodiment of a disk alignment apparatus200for patterned media production. Apparatus200passively aligns and imprints a substrate (e.g., a disk). Apparatus200has top die230and bottom die235portions. Top die230includes first air-bearing mandrel240disposed near a middle portion of top die230, and has a first tapered nose242oriented to face bottom die235. First air-bearing mandrel240has a diameter sized to engage an ID282of disk280. Top die230also has a first imprinting surface260disposed around first air-bearing mandrel240. In one embodiment, first imprinting surface260may include an elastomer pad to accommodate surface variations of disk580or imprinting surface260(e.g., an imprinting toil). In one embodiment, first imprinting surface260has a circular shape to match disk. A centerline290for first air-bearing mandrel240is aligned with a centerline292of first imprinting surface260. Support portions205,210stabilize top die portion230and bottom die portion235.

Bottom die portion235has second air-bearing mandrel245disposed near a middle portion, with a second tapered nose244oriented to first tapered nose242of first air-bearing mandrel240. As with first tapered nose242of first air-bearing mandrel240, second tapered nose244of second air-bearing mandrel245is also sized to engage an ID282of disk280. In one embodiment, bottom die235may also have a second imprinting surface262disposed around second air-bearing mandrel245. A centerline294for second air-bearing mandrel245is aligned with a centerline296of second imprinting surface262. In one embodiment, bottom die portion235of apparatus200rests in a dual air-bearing nest, with one planar surface276and one spherical surface278. The dual air-bearing nest of planar surface276and spherical surface278allows spherical seat250of bottom die portion235freedom of motion to rotate about a theoretical center298of the top surface of disk280.

In one embodiment of a method to align and imprint disk280with apparatus200, disk280may first be placed on bottom die portion235(e.g., by robot or P&P device) such that second tapered nose244of second air-bearing mandrel245engages an ID282of disk280. Specifically, disk280is placed on the lower mandrel245and is secured several thousandths of an inch above second imprinting surface262within a cavity265of bottom die portion235. The cavity265is sized slightly larger than disk280to contain disk280within bottom die portion235.

Disk280is initially axially located by the first tapered nose and then by the second tapered nose244of second air-bearing mandrel245of bottom die portion235. As discussed above, a duplicate precision air-bearing linear mandrel (e.g., first air-bearing mandrel240) resides in top die portion230. Upon closure of top and bottom die portions230,235, the noses242,244of first and second air-bearing mandrels240,245have three finger-like configurations with tapered faces which allow them to mesh, capturing disk280on both ID chamfers. Thus, the bottom die portion235aligns to top die portion230using centered disk280as the connecting medium. First air-bearing mandrel240of top die portion230is urged downward by its own weight (and air pressure if needed), and second air-bearing mandrel245of bottom die portion235is urged upward via a small differential air pressure. Bottom die portion235freely floats on a flat air-bearing plane276into alignment with the centerline290of top die portion230. Plane matching of first imprinting surface260and second imprinting surface262is attained by the passive movement of the spherical air bearing surface278of spherical seat250. Surface278has its radius of curvature focused at the center point of the top surface of the disk280to minimize relative motion between disk280and second imprinting surface262. In one embodiment, excess freedom of motion of spherical seat250may be controlled by cleats. Very low volumes of CDA may be used to support air-bearing mandrels240,245. As such, apparatus200, by utilizing a full-floating, multi-axis lower die portion and air-bearing mandrels, achieves auto-alignment of both sides of a disk to imprinting surfaces. If die sets205,210are very precise, the spherical alignment feature may be removed and the planar system retained to achieve coaxial alignment of205,210.

FIG. 3illustrates a cross-sectional view of another embodiment of a disk alignment apparatus for patterned media production. Apparatus300has top die portion330and bottom die portion335that establishes a fundamental side-to-side alignment and repeatability of patterned media (e.g., a disk). Bottom die portion335has air-bearing supported alignment mandrel340disposed near a center portion, with a tapered nose342extending towards top die portion330. Support portions305,310and columns315,320stabilize top die portion330and bottom die portion335.

Tapered nose342of air-bearing mandrel340is sized to engage an ID382of disk380. As described in greater detail below with respect toFIGS. 7A and 7B, imprinting surfaces360,362may be hermetically sealed over top and bottom portions330,335to form shallow cavities350,351,352,353. Top and bottom die portions330,335also have pressurized fluid outlets370,372,374,376in fluid communication with the hermetically sealed shallow cavities350,351,352,353for the delivery and removal of fluids (e.g., liquid or gas) used to press imprinting surfaces360,362on disk380. In one embodiment, apparatus300may have a total of four pressurized fluid outlets, although more or less than four may be utilized. A centerline390for air-bearing mandrel340of bottom die portion335is aligned with imprinting surfaces360,362disposed on top and bottom die portions330,335. Bottom die portion335also has spring345to allow mandrel340axial movement. All of the die parts may be of circular configuration and like materials, thereby minimizing thermal distortion and maintaining critical clearances at the air-bearing surfaces.

In one embodiment, imprinting surfaces360,362are made of compliant material to allow for flexibility when making contact with a disk substrate (e.g., disk380). The disk substrate may possess inherent variations in thickness which would require that imprinting surfaces360,362be flexible to conform to the variations.FIG. 7Aillustrates a cross-sectional view of one embodiment of imprinting surfaces710,712hermetically sealed over die portions720,722to form hermetically sealed cavities730,732. For clarity of explanation, the entire disk alignment apparatus is not shown. Imprinting surfaces710,712may be sealed to die portions720,722by welding (e.g., laser or braze), soldering, or electric arc welding. By welding imprinting surfaces710,712to die portions720,722, leakage of fluid passed through cavities730,732may be prevented during the imprinting process.FIG. 7Billustrates a cross sectional view of an alternative embodiment of hermetically sealing imprinting surface710,712over die portions720,722. In this embodiment, O-rings740,742may be used to seal imprinting surfaces710,712over die portions720,722. A slight vacuum at die cavities730,732may hold imprinting surfaces710,712in place until clamping action of die closure is established. Alternatively, elastomeric materials (e.g., rubber and other comparable polymers) and metals (e.g., for use with ultra high vacuum seals) may be used in place of o-rings.

It may be appreciated by one skilled in the art that a pre-formed cavity adjacent to an imprinting surface may not be necessary for the application of localized heating and cooling elements. In one embodiment, a mechanical piston may be disposed adjacent to the imprinting surface to force contact with a disk substrate. Alternatively, the application of a heating or cooling element to the imprinting surface may cause a cavity to form as the imprinting surface flexes to make contact with the disk substrate.

Referring again toFIG. 3, in one embodiment of a method to align and imprint a disk380with apparatus300, disk380is placed on air-bearing mandrel340of bottom die portion335(e.g., by a robot or P&P device). Upon placement, disk380residing several thousandths of an inch above imprinting surface362of the lower die cavity352. As top die portion330closes over bottom die portion335, disk380locks in place with ID382of disk380engaging the tapered nose portion342of air-bearing mandrel340. Upon closure of top and bottom die portions330,335a centerline396of disk380is aligned with the centerlines390,392of top and bottom die portions. Next, the cavities350,352underlying imprinting surfaces360,362are charged with high-pressure fluid (e.g., a gas or liquid) forcing the features of the imprinting surfaces into the polymer coating of disk. Fluid is delivered through pressurized fluid outlets370,372,374,376. Examples of fluids that may be used include, but are not limited to high-pressure gas (nitrogen), hydraulic oil, and thermal working fluids such as Dow Therm™ or Marlotherm N™. To complete the imprinting process, pressure is reduced to zero and the fluid is allowed to flow through the cavities followed by cooling fluid to carry off residual heat and cool the impressed surface of disk380. Cooling the disk and imprinting surface may facilitate the separation of the disk from the imprinting surface.

The coating of a disk substrate may be an integral part of a patterned substrate or removed after suitable development. By imprinting features in a coating via a stamper, it may be used as a stencil to enable patterning of the substrate surface by subsequent material additive or subtractive processes (e.g., plating through a mask or etching through a mask), and can often be facilitated if the imprinting is performed at an elevated substrate temperature. In the latter case the resultant mask would be removed after performing the additive or subtractive steps. Higher temperature can soften the material to be imprinted and thereby improve embossed feature fidelity and increase stamper life. Moreover, separation of the stamper from the imprinted surface may be facilitated by cooling the substrate below the imprinting temperature. Hence, it may be desirable to equip the press with elements to heat and cool the disk substrate prior to and after imprinting it via the stamper. Provision of such cooling and heating elements is preferably accomplished by placing such elements in close proximity to the back of each stamper. Localized heating and cooling of the disk substrate may not be necessary in order achieve successful stamping. The entire disk alignment apparatus (e.g., apparatus300) may be subjected to heating and cooling elements to stamp a disk substrate.

As explained above, one method of heating and cooling may include using hot and cool fluids in the cavities behind the imprinting surfaces (e.g., imprinting surfaces360,362), membranes, or foils. Alternatively, annular blocks may be disposed in close proximity to the imprinting surfaces. These blocks may contain embedded electric heating coils or thermoelectric cooling devices. In another embodiment, annular quartz heating lamps or resistive ribbons adhered disposed near the imprinting surface may be used in combination with cooling fluids.

FIG. 8illustrates one embodiment of a heating and cooling device for imprinting a disk. The device includes a thermodynamic press800having pressurized fluid sources in communication with fluid outlets (e.g.,370,372,374,376ofFIG. 3) of a disk alignment system for the delivery of heating and cooling elements for imprinting a disk substrate. For clarity of explanation, a partial cross-sectional view of disk substrate810is shown, with imprinting surface820disposed adjacent to disk substrate810. A hermetically sealed cavity830is disposed adjacent to imprinting surface820. Cavity830also has port860in fluid communication with heating element840and port862in fluid communication with heat exchanger870.

In operation, heating coils842heats a fluid844(e.g., a liquid or gas) contained in heating element840to a working temperature. Piston805of heating element840displaces hot, working fluid844from heating element840through port860and into cavity830. Working fluid exits cavity830through port862displacing an inert gas (e.g., Nitrogen) towards heat exchanger870. Check valves880,882may be activated to stop a free-flow of working fluid844and allow piston805to achieve a pre-selected force to compress imprinting surface820against disk substrate810by transferring the heat of working fluid844. Piston805may then be retracted, lowering a system pressure, and withdrawing hot working fluid844through fluid return line890. Chilled gas from heat exchanger870follows and replaces the exiting hot fluid from cavity830and cools imprinting surface820.

FIG. 4illustrates a perspective view of another embodiment of a disk alignment apparatus400for patterned media production. Apparatus400aligns and imprints a substrate (e.g., a disk). Apparatus400has top die portion430and bottom die portion435that establishes fundamental repeatability of the patterned media (e.g., a disk). Support portions405,410and columns412,414,416(a fourth column is not shown in this view) stabilize top die portion430and bottom die portion435. Bottom die portion435has air-bearing supported alignment mandrel (not shown) disposed near a center portion, with a tapered nose445extending towards top die portion430. Tapered nose445of air-bearing mandrel is sized to engage an ID482of disk480. Top and bottom portions430,435also have first and second imprinting surfaces. In this view, only second, imprinting surface462is shown.

In one embodiment, first and second imprinting surfaces460,462are held in place by pico-actuators470,472, which control side-to-side movement of first and second imprinting surfaces460,462. Top and bottom die portions430,435also have pressurized fluid outlets450,452for the delivery and removal of fluids used to charge annular pistons (not shown), thus press imprinting surfaces on disk480. A centerline490for air-bearing mandrel440of bottom die portion435is aligned with imprinting surfaces460,462disposed on top and bottom die portions430,435. All of the die body elements and air-bearing mandrel440are of circular configuration and like materials, thus minimizing thermal distortion and maintaining critical clearances at the air-bearing surfaces.

In one embodiment of a method to align and imprint a disk480with apparatus400, disk480is placed on the tapered nose portion445of mandrel440(e.g., by a robot or P&P device), residing several thousandths of an inch above second imprinting surface462of lower die portion435. Top die portion430is closed over disk480and locked in place against imprinting surfaces460,462. Upon closure of top and bottom die portions430,435, a centerline of disk480is aligned with the centerlines of top and bottom die portions430,435(centerlines are not shown in this perspective view of apparatus400). The cavities (not shown) underlying the imprinting surfaces460,462are then charged with high-pressure gas forcing the imprint features into the polymer coating. Fluid is delivered through pressurized fluid outlets450,452. To complete the imprinting process, pressure is reduced to zero and a purging gas flows through the cavities to carry off residual heat and chill the impressed surfaces of disk480. In an alternative method, a charge of combustible gas, such as hydrogen and oxygen, may be used to create heat and percussive pressure to emboss the imprinting surfaces into the polymer layer of disk480. Subsequent purging of the cavities cools the foil and polymer.

FIG. 5illustrates, in flowchart form, one method for passively aligning a disk for patterned media production. The method starts at block510by providing a die set having an upper portion and a lower portion, with a surface of the imprinting surface or foil disposed on the lower portion and facing the upper portion. Next, at block520, a disk floats above the imprinting surface within a cavity of the lower portion. At block530, an ID of the disk engages a tapered nose portion of an air-bearing mandrel coupled to the upper portion of the die set. At block540, top die portion closes over the lower portion, such that tapered nose portion of the air-bearing mandrel guides the floating disk ID into coincident alignment with a centerline of the air-bearing mandrel and the imprinting surface.

FIG. 6illustrates, in flowchart form, another method for passively aligning a disk for patterned media production. The method starts at block610by providing a die set having an upper portion and a lower portion, with a surface of an imprinting foil disposed on the lower portion and facing the upper portion. At block620, a disk positioned above the imprinting foil within a cavity of the lower portion. At block630, an ID of the disk engages a first tapered nose portion of a first air-bearing mandrel coupled to the upper portion of the die set. At block640, a second tapered nose portion of a second air-bearing mandrel, coupled to the upper portion of the die set, intermeshes with the first tapered nose portion. Upon closure of top and bottom portions, the first and second tapered nose portions guides the lower die via the disk ID into coincident alignment with a centerline of the fist and second air-bearing mandrels and the imprinting foils.