Abstract:
A method and a medium for laser imaging is herein disclosed. The medium incorporates one or more types of microstructures having a predetermined heat or radiation modifiable optical characteristic such as color, scattering, diffusion, diffraction, interference and iridescence. Associated intimately with the microstructures is a radiation antenna that acts to absorb radiation from a radiation source. The radiation antenna and source are attuned to one another to efficiently transfer energy therebetween and subsequently to the microstructures; this transfer of energy results in the modification of an optical characteristic of the microstructures to form an image on the medium. The medium has one or more layers that may include both the radiation antenna and the microstructures. Alternatively, the microstructures and radiation antenna may be included in separate layers. Coatings that incorporate one or more layers that include distinct microstructures and radiation antennae are also contemplated.

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to media and mechanisms for laser imaging. More particularly the present invention relates to media having a substrate that incorporates microstructures that may be readily altered to effect the formation of images thereon. The present invention also includes a printing mechanism for forming images on the aforementioned media. 
     BACKGROUND OF THE INVENTION 
     The use of microstructures in printable media is well known. Most such arrangements utilize reflective microstructures to provide an image, pattern, or color that changes with the angle at which the media is viewed. The microstructures in question generally function by diffraction, interference, scattering, diffusion, transmission or reflection of light of a preselected wavelength or by polarizing reflected light. Other methods and structures for producing an optically discernable image, pattern, or color using microstructures are also known. 
     Generally, images, colors, or patterns are produced by directly applying or depositing microstructures onto the media in a desired arrangement prior to the use of the media, i.e. the images, colors, or patterns are printed on the media. Secondary images, colors, or patterns may be applied to the media over the pre-existing microstructural images, patterns, or colors. In other cases molding, stamping, patterning, pressure embossing, or mechanical abrasion of selected areas are used to produce the optical patterns. In recent times, high power lasers have also been used to ablate, melt, or otherwise damage the microstructures on the media to form a secondary image. In short, the formation of images on media using microstructures is relatively expensive, requires complicated and dangerous lasers, and/or may damage or chemically decompose the media being printed. Accordingly, there is a need for a media and a method of printing using microstructures that is inexpensive, flexible, and which uses apparatuses that are safe and which do not damage the media being printed. 
     It is therefore an object of the present invention to provide media having a substrate that may be readily modified using relatively low power light source sources. It is another object of the invention to provide media for printing having microstructural features that may be readily modified to form an image without damaging the substrate of the media. One other object of the present invention involves the provision of a printing apparatus that utilizes a relatively low power light/radiation source to form an image on media in such a way as to avoid damaging or chemically decomposing the media. 
     These and other objects, aspects, features and advantages of the present invention will become more fully apparent upon careful consideration of the following Detailed Description of the Invention and the accompanying Drawings, which may be disproportionate for ease of understanding, wherein like structure and steps are referenced generally by corresponding numerals and indicators. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is realized in a printing medium, a printing mechanism and a method of printing in which microstructures having a chosen optical characteristic are applied to a printing medium. Radiation within a predetermined range of wavelengths is applied by a printing mechanism to the medium and is absorbed as heat energy by a radiation antenna that is selectively sensitive to the applied radiation. 
     The printing medium of the present invention generally includes a coated or uncoated substrate to which is applied a coating that incorporates microstructures having a selected optical characteristic, color, for example. 
     A printing mechanism of the present invention will include one or more source radiation sources that output light within a range of wavelengths to which a corresponding radiation antenna in the media is sensitive. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross sectional view of a printing medium in an embodiment of the present invention, the printing medium having a coating that incorporates microstructures therein. 
         FIG. 2  is a cross sectional view of a printing medium in an embodiment of the present invention, the printing medium having a coating with microstructures formed on the surface of the coating. 
         FIG. 3  is a cross sectional view of a printing medium in an embodiment of the present invention, the printing medium having multiple coatings that incorporate discrete microstructures therein. 
         FIG. 4  is a cross sectional view of a printing medium in an embodiment of the present invention, the printing medium having multiple coatings, at least one of which incorporates microstructures therein and another coating having microstructures formed on the surface thereof. 
         FIG. 5  is a cross sectional view of a printing medium in an embodiment of the present invention, the printing medium having multiple coatings containing discrete microstructures, the coatings being adapted for multicolor printing. 
         FIG. 6  is a schematic illustration of a printing mechanism in an embodiment of the present invention, the printing mechanism having a single radiation source mounted to a printhead. 
         FIG. 7  is an illustration of a printing mechanism in an embodiment of the present invention, the printing mechanism of a type that may incorporate a radiation source. 
         FIG. 8  is a schematic illustration of a printer in an embodiment of the present invention, the printer having multiple radiation sources mounted to a printhead. 
         FIG. 9  is a schematic illustration of a printer in an embodiment of the present invention, the printer having multiple printheads that may be adapted to mount thereon one or more radiation sources. 
         FIG. 10  is a schematic illustration of a reflector in an embodiment of the present invention, the reflector used to reflect light from a radiation source onto a printing medium. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description of the invention, reference is made to the accompanying drawings that form a part hereof and in which is shown, by way of illustration, specific embodiments in which the invention may be practiced. In the drawings, like numerals describe substantially similar components throughout the several views. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims and equivalents thereof. 
     The present invention generally includes a medium for printing and a method of printing that involves the use of certain types of microstructures in conjunction with radiation sources and radiation antennae. In a basic embodiment, a substrate of the printing media has applied thereto microstructures that impart a desired optical characteristic to the substrate. The microstructures have associated therewith a radiation antenna that facilitates the use of relatively low powered light sources, such as a light emitting diode laser or the like, to be used to develop or modify the desired optical characteristic of the microstructures, thereby forming an image on the media. 
       FIG. 1  illustrates one embodiment of the present invention in the media  10  having a substrate  12  to which is applied one or more layers  14 . The layer(s)  14  includes microstructures  16  embedded in a carrier material that includes a compound or material, hereinafter referred to as a radiation antenna, which is generally uniformly dispersed within layer  14 . The carrier material of layer  14  may include many useful materials such as binders, fillers, and colorants, in addition to the radiation antenna. Note that although  FIG. 1  illustrates layer(s)  14  applied to both sides of the substrate  12 , layer(s)  14  may be applied to one or both of the sides of the substrate  12 . 
     Microstructures  16  impart one or more optical characteristics to the media  10 . As used herein, the term “microstructure” may refer to discrete beads, chips, films, voids or bubbles, or fluid reservoirs that reflect and/or polarize light that is incident thereupon and three-dimensional structures formed in or on the layer(s)  14  on the surface of the of media  10  to impart a desired optical characteristic. Accordingly, the term “microstructure” is to be construed broadly and may include other types of structures and materials of similar function not specifically described herein. The term “optical characteristic” refers to any optically detectable characteristic of the media  10 , including, but not limited to color, refraction, dispersion, iridescence, and other similar optical characteristics. Note that optical characteristics include optical features that are visible to the human eye and to optical devices. 
     In one embodiment, the carrier material of layer  14  is relatively opaque and therefore only microstructures  16  on the surface of layer  14  will impart their optical characteristics to the media  10 . In another embodiment, the carrier material of layer  14  may be at least partially transmissive with respect to incident radiation and in this circumstance, most or all of the microstructures  16  present in layer  14  will impart their optical characteristics to the media  10 . 
     The carrier material containing the microstructures  16  may be applied to one or both sides of the substrate  12 . The carrier material may be applied to the entire surface of the substrate  12  using a typical wet end coating process such as a doctor blade, screen printer, roller coater, offset printing, pad printing, spray coating, spin coating, gravure, curtain coating, slot-die coating, ink jet printing and the like. Alternatively, microstructures  16  may be applied to the surface of the substrate  12  in a selective manner as by printing or screening or may be formed separately from the substrate  12  as a planar film (not shown) that is later laminated therewith to form an image or pattern thereon. Hereinafter, the application of microstructures  16  to a substrate  12  will be referred to as the formation of a first image. The first image may include, but is not limited to, solid colors, regular and irregular patterns, line art, and text. In some embodiments, the layer  14  having microstructures  16  in a carrier material may be used simply to impart a desired finish and color to a sheet of paper. In other embodiments, layer  14  having microstructures  16  in a carrier material may be used to form various types of security features common to sensitive documents such as bank notes and the like. 
     The substrate  12  of the media  10  may be any suitable substrate including, but not limited to, paper, films, cloth, wood, metal and the like. The substrate  12  may have preexisting coatings applied thereto prior to the application of a layer  14  thereto. Once layer  14  has been applied to the substrate  12  and properly cured or otherwise treated to allow further processing, a second image may be formed on the media  10  by modifying the optical characteristic(s) of the microstructures  16 . This is done by chemically curing or developing the microstructures (where the microstructures are photosensitive) or by heating the microstructures  16  to a point at which their optical characteristics are modified in a desired manner. Modifying the microstructures  19  may also be referred to as ‘developing’ the second image on the media  10 . In some embodiments, heating the microstructures  16  may result in the layer  14  becoming transmissive, thereby resulting in those portions of the media  10  where the modified microstructures reside effectively taking on at, at least partially, an optical characteristic of the substrate  12  or underlying layers  14 , for example color. In one embodiment, microstructures  16  may be adapted to reflect and diffuse substantially all visible light, thereby imparting a “white” color to the media  10 . In some embodiments, this is accomplished by forming or applying a grating line pattern on the surface of the media  10 . 
     By curing or heating one or more of the microstructures  16  to a predetermined point, the microstructures  16  are modified such that they reflect only light in chosen wavelengths, thereby imparting a different color to that portion of the media where the modified microstructures reside. In some embodiments, the microstructures  16  may, after heating, become absorptive of substantially all visible light and will therefore render black those portions of the media  10  where the modified microstructures reside. It is to be understood that the starting and ending optical characteristics of the microstructures  16  may vary depending on the physical or chemical makeup of the microstructures themselves. Accordingly, such optical characteristics as color and reflectance, among others, may vary between different types of microstructures. 
     The present invention utilizes a radiation source and a radiation antenna that are attuned to one another to precisely and efficiently transfer energy from the source to the antenna in a selected portion of the media  10  to modify the optical characteristics of the microstructures. Radiation antennae that absorb light energy within a specified range of wavelengths and either pass or reflect substantially all other wavelengths of light are incorporated in and/or around the microstructures  16 . In the embodiment illustrated in  FIG. 1 , the radiation antenna is incorporated directly into the carrier material of layer  14  such that the radiation antenna surrounds or is at least immediately adjacent to or within the microstructures  16 . The radiation source outputs substantially only light within the predetermined range of wavelengths to which the radiation antenna is attuned. As substantially all of the light that is incident upon the media  10  is of a wavelength that can and likely will be absorbed, there is realized a highly efficient transfer of energy from the radiation source to the media  10  and more specifically, to the microstructures themselves. Accordingly, much less power is required from the radiation sources than was otherwise required in prior art laser printing devices utilizing microstructures. Furthermore, because the energy transfer from the radiation source to the radiation antenna takes place immediately adjacent to the microstructures themselves, only minutely localized heating of the layer  14  is required. This localized heating/development eliminates or at least limits damage to the media  10  and avoids problems such as burning and delamination of the layers  14  from the substrate  12 . 
     As illustrated in  FIG. 6 , a radiation source  20  delivers light to a selected portion of the media  10  to modify or develop the optical characteristics of the microstructures in that selected portion. One or more radiation sources  20  may be adapted for use in a printing mechanism  30  of the type illustrated in  FIG. 6 . In one embodiment, the radiation source  20  is a laser powered by a light emitting diode. Such lasers are very inexpensive and because their power output is relatively low, these lasers are less likely to damage the media  10  or cause unsafe conditions. This type of radiation source  20  is also quite flexible as it may be readily attuned through known means to output light in many different ranges of wavelengths. 
       FIG. 1  illustrates the use of a microstructure  16  that is a discrete structure incorporated into a carrier material for application to a substrate  12  in a layer  14 .  FIG. 2  illustrates the formation of a three-dimensional microstructure  16 ′ into the surface of the media  10 . Microstructures  16 ′ are constructed and arranged to reflect and/or diffract incident light to impart their selected optical characteristics. Modifying the physical structure of the microstructures  16 ′ necessarily modifies their optical characteristics. 
     The embodiment shown in  FIG. 2  is similar to the embodiment of  FIG. 1  in that both have a substrate  12  to which on or more layers  14  have been applied. Layers  14  may have many constituent parts, but always include a radiation antenna as described above. The layers  14  may be applied directly to a bare or uncoated substrate  12  or may be applied to a substrate  12  having one or more pre-existing coatings applied thereto. Note that layers  14  may be applied using any of a number of wet end coating methodologies. Samples of some suitable coating methodologies are described in The Printing Ink Manual; Leach, Robert; Pierce, Ray (Eds.), Fifth Edition, 1999, 993 p., ISBN: 0-948905-81-6, herein incorporated by reference. Alternatively, microstructures  16  may be selectively applied by printing, screening, embossing, engraving, or may be formed as an independent layer or film and later laminated to substrate  12 . 
     Microstructures  16 ′ may be formed by many methods including, but not limited to, engraving, pressing, ablation, etching, selective deposition as by printing or screening, or by including the microstructures  16 ′ in an independent layer or film that is laminated to substrate  12 . Three dimensional microstructures  16 ′ are typically formed in the surface of the layer  14 , though it is to be understood that where multiple translucent layers  14  are applied to a substrate  12 , it may be possible to form three dimensional microstructures  16 ′ at the interface between the respective layers  14 . Microstructures  16 ′ have their optical characteristics modified in the same manner as described above in conjunction with  FIG. 1 . Light or radiation within a specified range of wavelengths from a radiation source  20  is played upon a predetermined location of the media  10  and is readily absorbed by the attuned radiation antenna in layer(s)  14 . The energy from the radiation source  20  efficiently heats the microstructures  16 ′ to a point where the three-dimensional structure of the microstructures  16 ′, and hence their optical characteristics, are modified. In this manner, a secondary image is formed on the media  10 . 
       FIG. 3  illustrates another embodiment of the media  10  in which the radiation antenna is contained in a layer  40  that is separate from the layer  42  in which the discrete microstructures  16  are disposed. As previously described, one or more layers  40  are applied to one or more sides of a substrate  12  that may or may not have pre-existing coatings (not shown) applied thereto. Layer(s)  40  includes, among other things, a radiation antenna that is disposed within a carrier material that may itself include other typical constituent parts such as binders, fillers, and the like. A layer  42 , which includes microstructures  16  disposed within a carrier material, may be applied over one or both layers  40 , depending on how many such layers  40  are laid down on substrate  12 . Note that the relative positions of the layers  40  and  42  may be reversed so long as light from a radiation source may be directed onto the radiation antenna and the radiation antenna can transfer heat to the microstructures  16 . Note also that where the radiation antenna and the microstructures  16  are disposed in separate layers as illustrated in  FIG. 3 , and particularly for those embodiments where the radiation antenna is disposed in a layer away from the surface of the media  10 , it will be desirable for the outermost layer, in the embodiment illustrated in  FIG. 3  layer  42 , to be at least partially transmissive with respect to light from the radiation source  20 . In this manner, light from the radiation source  20  will pass through layer  42  and will be absorbed by the light absorbing material in layer  40 , which in turn transfers heat to the microstructures  12  in layer  42  to modify their optical characteristics. 
       FIG. 4  illustrates another embodiment of the media  10  that utilizes three-dimensional microstructures  16 ′ in a layer separate from the layer in which is disposed the radiation antenna. In the embodiment of  FIG. 4 , one or more layers  42  are applied to the substrate  12 , which may or may not have pre-existing coatings applied thereto. Layer  42  includes a carrier material in which is disposed a radiation antenna as described above in conjunction with  FIG. 3 . One or more layers  42  are applied over the layers  40  applied to the substrate  12 . Layers  42  have formed on outer surface thereof three-dimensional microstructures  16 ′ that have one or more desired optical characteristics. Light from a radiation sources played upon a selected portion of the media  10  and is absorbed by the radiation antenna of layer  40 , which in turn transfer heat to the microstructures  16 ′ of layer  42  to modify the optical characteristics of the microstructures  16 ′. In this embodiment, it will be necessary for layer  42  to be at least partially transmissive with respect to the light output by the radiation sources that the optical characteristics of the microstructures  16 ′ may be modified to form a secondary image on the media  10 . 
       FIG. 5  illustrates one embodiment of media  100  intended for multicolor printing. Media  100  has a substrate  102  to which are applied multiple layers  104 ,  106 , and  108  that incorporate radiation antennas and microstructures. Note that layers  104 ,  106 , and  108  are applied to both sides of substrate  102  so that the resulting media  10  may be used in a duplex printing process. It is to be understood however, that layers  104 ,  106 , and  108  may be applied to only a single side of substrate  102 . Prior to the application of layers  104 ,  106 , and  108 , substrate  102  may be uncoated or may have one or more pre-existing coatings (not shown) applied thereto. 
     Each of the layers  104 ,  106 , and  108  comprise a carrier material that may include binders, fillers, and other constituent parts, including respective radiation antennas and microstructures  105 ,  107 , and  109 . The radiation antennas of each layer  104 ,  106 , and  108  are attuned to radiation in substantially mutually exclusive ranges of wavelengths. Radiation played upon the media  100  that is outside of the sensitive range of wavelengths for a given layer  104 ,  106 , or  108  will not be absorbed by the radiation antenna thereof, but will be partially or wholly passed therethrough and/or partially reflected. Because the multiple layers  104 ,  106 , and  108  are applied the one over the other, it is important that the outer layers be at least partially transmissive with respect to light output by the radiation sources to which the inner layers are sensitive. In this manner, light from the radiation sources may be directed at the radiation antenna of a chosen layer through the outer layers such that all or part of a secondary image can be formed by modifying the microstructures that reside in the chosen layer. 
     In one embodiment of the media  100 , pair R of layers  104  include microstructures  105  that are constructed and arranged to reflect red light upon modification, pair B of layers  106  include microstructures  107  that are constructed and arranged to reflect blue light upon modification, and pair G of layers  108  include microstructures  109  that are constructed and arranged to reflect green light upon modification. In their unmodified state, microstructures  105 ,  107 , and  109  may reflect all light incident upon media  100 , thereby giving the media a white color, or the microstructures may be transmissive of light incident upon media  100  such that the inherent color of the substrate  102  will define the color of the media  100  before any of the microstructures are modified. Note that the microstructures of layers  104 ,  106 , and  108  may take on any suitable color or optical characteristic and are not limited to the colors/optical characteristics described above. 
     A secondary image is printed upon media  100  in the same manner as described herein above in conjunction with  FIGS. 1-4 . Where a portion of an image, pattern, or text is to be printed on media  100  in one or a combination of the colors/characteristics represented by layers  104 ,  106 , and  108 , the radiation sources that are attuned to the selected layers are activated to play light on the desired portion of the media  100 . Where, for example, the portion of the image that is to be printed on the selected portion of media  100  is to be red, the radiation source that outputs light to which the radiation antenna of layers  104  is sensitive is activated. A sufficient portion of light from the selected radiation source passes through layers  106  and  108  and is incident upon layer  104  such that the radiation antenna absorbs the light. Heat is transferred from the radiation antenna of layer  104  to the microstructures  105  thereof, which are modified to exhibit the desired optical characteristic, in this instance the characteristic being to be reflective of red light. The microstructures  107  and  109  of the blue and green pairs of layers, B and G, may be similarly modified. 
     Media  100  may be divided into a grid of locations or pixels P. Each of the pixels P may be colored as described above by modifying the optical characteristics of the microstructures in the layers  104 ,  106 , and  108  of the media  100  at pixel P. Radiation sources may be operated as by a controller (not shown) of printer  30  to form a pattern of colored or modified pixels P across the surface of the media  100  to form a desired image without requiring the application of a colorant such as an ink, dye, or toner to the surface of the media  100 . 
       FIG. 7  illustrates schematically a printing mechanism  30  adapted to carry out a printing process on media  10  according to one or more embodiments of the present invention. Printer  30  may be adapted for use as a line type printer or may incorporate one or more movable printhead, each printhead incorporating in turn one or more radiation sources  20 . Note that as printing processes according to the present invention may be carried out in myriad ways, it is to be understood that the present invention is not limited to printers  30  having a configuration similar to that illustrated in  FIG. 7 . 
       FIGS. 6 and 8  illustrate schematically embodiments of a printer  30  that has a printhead  40  mounted upon shaft  42 . Printhead  40  is laterally movable with respect to media  10  upon shaft  42  and media  10  may be moved with respect to the printhead  30  by a media handling mechanism (not shown). A number of printer architectures of a type that may be adapted to control the relative positions of a printhead  40  and media  10  are described by Bockman et al. in their article “HP DeskJet 1200C Printer”, Hewlett-Packard Journal, February 1994, pages 55-66, hereby incorporated by reference. Note that other printer architectures may also be used or adapted. 
     Printhead  40  includes one or more radiation sources  20   a ,  20   b , and  20   c  that output light within predetermined ranges of wavelengths as described hereinabove. The radiation sources  20   a ,  20   b , and  20   c  may each be adapted to output light in different wavelength ranges, or in the same wavelength ranges, depending on whether the printhead  40  is intended for multicolor printing or the multiple radiation sources  20   a ,  20   b , and  20   c  are simply intended to support one another in a single color printing operation. In use, the printhead  40  and media  10  are manipulated by the printer  30  to align the radiation sources  20   a ,  20   b , and  20   c  with a desired location on the media  10 . One or more of the radiation sources  20   a ,  20   b , and  20   c  are then activated to play light upon the media  10 . The light from radiation sources  20   a ,  20   b , and  20   c  is absorbed by the respective radiation antennas in or on the media  10 , the light energy being absorbed thereby as heat that modifies the selected microstructures to create a secondary image on the media  10 . 
     While the radiation sources  20   a ,  20   b , and  20   c  in  FIG. 9  may be arranged in a parallel fashion as shown, it may be desirable to provide a mounting structure (not shown) in the printhead  40  that will not only provide the necessary electrical and/or control connections between the radiation sources  20   a ,  20   b , and  20   c  and the printer  30 , but will also focus the respective radiation sources  20   a ,  20   b , and  20   c  on the same location of the media  10 . 
       FIG. 9  illustrates schematically another embodiment of a printer  30  that incorporates multiple printheads  40 , each mounted for lateral movement on respective shafts  42 . The multiple printheads  40  may operate independently of one another, each of the printheads  40  operating alone to print an image on media  10 . Alternatively, each of the multiple printheads  40  may be adapted and controlled by printer  30  to operate cooperatively to print a secondary image on media  10 . Note that the printheads  40  illustrated in  FIG. 10  may collectively operate as a line type printhead or may operate individually. 
       FIG. 10  illustrates schematically an embodiment of the present invention in which a radiation source  20  is fixedly mounted within a printer (not shown). Light output by the radiation source  20  is collected by a reflector  44  that is rotatively mounted to reflect and focus the light from the radiation source  20  onto the media  10  as shown. The reflector  20  may be rotated about a single axis, as shown, or may be adapted for rotation about multiple axes. As media  10  moves with respect to the radiation source  20  and reflector  44  (see arrow  46 ), radiation from the radiation source  20  is played across the surface of the media  10  to form a secondary image. 
     As described hereinabove, the radiation antennae act as an efficient energy absorber and are included in the carrier material as a component that optimizes the development of the microstructures upon exposure to radiation at a predetermined exposure time and/or wavelength. In one embodiment, the radiation source and radiation antenna will be optimized to develop the microstructures on the media  10  over a range of wavelengths of about 200 nm to about 900 nm. It is to be understood however, that wavelengths outside this range can be used by adjusting composition or other characteristics of the radiation antenna and/or the radiation source. 
     Suitable radiation antennae can be selected from a number of radiation absorbing materials such as, but not limited to, aluminum quinoline complexes, porphyrins, porphins, indocyanine dyes, phenoxazine derivatives, phthalocyanine dyes, polymethyl indolium dyes, polymethine dyes, guaiazulenyl dyes, croconium dyes, polymethine indolium dyes, metal complex IR dyes, cyanine dyes, squarylium dyes, chalcogeno-pyryloarylidene dyes, indolizine dyes, pyrylium dyes, quinoid dyes, quinone dyes, azo dyes, and mixtures or derivatives thereof. Other suitable radiation antennae can also be used in the present invention and are known to those skilled in the art and can be found in such references as “Infrared Absorbing Dyes”, Matsuoka, Masaru, ed., Plenum Press, New York, 1990 (ISBN 0-306-43478-4) and “Near-Infrared Dyes for High Technology Applications”, Daehne, Resch-Genger, Wolfbeis, Kluwer Academic Publishers (ISBN 0-7923-5101-0), both incorporated herein by reference. 
     Suitable radiation antennae efficiently absorb electromagnetic radiation of a specific wavelength or range of wavelengths. Optimization of a coupled radiation source and radiation antenna involves utilizing a radiation source that emits radiation substantially at or near the wavelength that the radiation antenna most efficiently absorbs. In one embodiment for example, the development of the microstructures is optimized within a range of wavelengths that includes infrared radiation from about 720 nm to about 900 nm. Common CD-burning lasers have a wavelength of about 780 nm and can be adapted for use as a radiation sources for developing selected microstructures on the media  10 . Examples of radiation antennae that are suitable for use in the infrared range can include, but are not limited to, polymethyl indoliums, metal complex IR dyes, indocyanine green, polymethine dyes such as pyrimidinetrione-cyclopentylidenes, guaiazulenyl dyes, croconium dyes, cyanine dyes, squarylium dyes, chalcogenopyryloarylidene dyes, metal thiolate complex dyes, bis(chalcogenopyrylo)polymethine dyes, oxyindolizine dyes, bis(aminoaryl)polymethine dyes, indolizine dyes, pyrylium dyes, quinoid dyes, quinone dyes, phthalocyanine dyes, naphthalocyanine dyes, azo dyes, hexafunctional polyester oligomers, heterocyclic compounds, and combinations thereof. Several specific polymethyl indolium compounds are available from Aldrich Chemical Company and include 2-[2-[2-chloro-3-[2-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)-ethylidene]-1-cyclopenten-1-yl-ethenyl]-1,3,3-trimethyl-3H-indolium perchlorate; 2-[2-[2-Chloro-3-[2-(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)-ethylidene]-1-cyclopenten-1-yl-ethenyl]-1,3,3-trimethyl-3H-indolium chloride; 2-[2-[2-chloro-3-[(1,3-dihydro-3,3-dimethyl-1-propyl-2H-indol-2-ylidene)ethylidene]-11-cyclohexen-1-yl]ethenyl]-3,3-dimethyl-1-propylindolium iodide; 2-[2-[2-chloro-3-[(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl]ethenyl]-1,3,3-trimethylindolium iodide; 2-[2-[2-chloro-3-[(1,3-dihydro-1,3,3-trimethyl-2H-indol-2-ylidene)ethylidene]-1-cyclohexen-1-yl]ethenyl]-1,3,3-trimethylindolium perchlorate; 2-[2-[3-[(1,3-dihydro-3,3-dimethyl-1-propyl-2H-indol-2-ylidene)ethylidene]-2-(phenylthio)-1-cyclohexen-1-yl]ethenyl]-3,3-dimethyl-1-propylindolium perchlorate; and mixtures thereof. Alternatively, the radiation antenna can be an inorganic compound, e.g., ferric oxide, carbon black, selenium, or the like. Polymethine dyes or derivatives thereof such as a pyrimidinetrione-cyclopentylidene, squarylium dyes such as guaiazulenyl dyes, croconium dyes, or mixtures thereof can also be used in the present invention. Suitable infrared sensitive pyrimidinetrione-cyclopentylidene radiation antennae include, for example, 2,4,6(1H,3H,5H)-pyrimidinetrione 5-[2,5-bis[(1,3-dihydro-1,1,3-dimethyl-2H-indol-2-ylidene)ethylidene]cyclopentylidene]-1,3-dimethyl-(9CI) (S0322 available from Few Chemicals, Germany) 
     In another embodiment, a radiation antenna can be selected to optimize the development of microstructures on the media  10  in a wavelength range from about 600 nm to about 720 nm and more specifically at about 650 nm. Non-limiting examples of suitable radiation antennae for use in this range of wavelengths can include indocyanine dyes such as 3H-indolium, 2-[5-(1,3-dihydro-3,3-dimethyl-1-propyl-2H-indol-2-ylidene)-1,3-pentadienyl]-3,3-dimethyl-1-propyl-,iodide), 3H-indolium, 1-butyl-2-[5-(1-butyl-1,3-dihydro-3,3-dimethyl-2H-indol-2-ylidene)-1,3-pentadienyl]-3,3-dimethyl-,perchlorate, and phenoxazine derivatives such as phenoxazin-5-ium, 3,7-bis(diethylamino)-,perchlorate. Phthalocyanine dyes such as silicon 2,3-napthalocyanine bis(trihexylsilyloxide) and matrix soluble derivatives of 2,3-napthalocyanine (both commercially available from Aldrich Chemical), matrix soluble derivatives of silicon phthalocyanine (as described in Rodgers, A. J. et al., 107 J. Phys. Chem. A 3503-3514, May 8, 2003), matrix soluble derivatives of benzophthalocyanines (as described in Aoudia, Mohamed, 119 J. Am. Chem. Soc. 6029-6039, Jul. 2, 1997), phthalocyanine compounds such as those described in U.S. Pat. Nos. 6,015,896 and 6,025,486 (which are each incorporated herein by reference), and Cirrus 715, a phthalocyanine dye available from Avecia, Manchester, England, may also be used. 
     In another embodiment, a radiation source such as a laser that outputs light having blue and indigo wavelengths ranging from about 300 nm to about 600 nm can be used to develop the microstructures on the media  10 . In particular, radiation sources such as the lasers used in certain DVD and laser disk recording equipment emit energy at a wavelength of about 405 nm. Radiation antennae that most efficiently absorb radiation in these wavelengths may include, but are not limited to, aluminum quinoline complexes, porphyrins, porphins, and mixtures or derivatives thereof. Some specific examples of suitable radiation antennae suitable for use with radiation sources that output radiation between 300 and 600 nm include 1-(2-chloro-5-sulfophenyl)-3-methyl-4-(4-sulfophenyl)azo-2-pyrazolin-5-one disodium salt; ethyl 7-diethylaminocoumarin-3-carboxylate; 3,3′-diethylthiacyanine ethylsulfate; 3-allyl-5-(3-ethyl-4-methyl-2-thiazolinylidene) rhodanine (each available from Organica Feinchemie GmbH Wolfen), and mixtures thereof. Other examples of suitable radiation antennae include aluminum quinoline complexes such as tris(8-hydroxyquinolinato) aluminum (CAS 2085-33-8) and derivatives such as tris(5-cholor-8-hydroxyquinolinato) aluminum (CAS 4154-66-1), 2-(4-(1-methyl-ethyl)-phenyl)-6-phenyl-4H-thiopyran-4-ylidene)-propanedinitril-1,1-dioxide (CAS 174493-15-3), 4,4′-[1,4-phenylenebis(1,3,4-oxadiazole-5,2-diyl)]bis N,N-diphenyl benzeneamine (CAS 184101-38-0), bis-tetraethylammonium-bis(1,2-dicyano-dithiolto)-zinc(II) (CAS 21312-70-9), 2-(4,5-dihydronaphtho[1,2-d]-1,3-dithiol-2-ylidene)-4,5-dihydro-naphtho[1,2-d]1,3-dithiole, all available from Syntec GmbH. Other examples of specific porphyrin and porphyrin derivatives can include etioporphyrin 1 (CAS 448-71-5), deuteroporphyrin IX 2,4 bis ethylene glycol (D630-9) available from Frontier Scientific, and octaethyl porphrin (CAS 2683-82-1), azo dyes such as Mordant Orange CAS 2243-76-7, Merthyl Yellow (60-11-7), 4-phenylazoaniline (CAS 60-09-3), Alcian Yellow (CAS 61968-76-1), available from Aldrich chemical company, and mixtures thereof. 
       FIG. 11  illustrates another embodiment of media  120  that may include photosensitive curable polymers such as acrylate derivatives, oligomers, and monomers. These photosensitive curable polymers, such as, for example, certain lacquers, are deposited as a layer  122  on a medium  121 . The layer  122  may incorporate a separate radiation antenna or the curable polymer may itself be a radiation antenna of sorts. Coatings or layers  122  may have incorporated therewith microstructures or may be independent from layers  124  that include microstructures. The absorption of energy by the radiation antenna in layer  122  initiates a chemical reaction(s) that cures the curable polymer. In one embodiment, radiation antennae used in conjunction with the curable polymers are selected for curing the aforementioned polymers using ultraviolet (UV) or electron beam curing systems and may include, by way of example, benzophenone derivatives. Other examples of radiation antennae that are useful as photoinitiators for free radical polymerization monomers and pre-polymers can include, but are not limited to, thioxanethone derivatives, anthraquinone derivatives, acetophenones, and benzoine ethers. Additional examples of UV curable polymers that may be prepared and coated as dispersions in water or solvents, solutions, or solid melts include polyvinyl alcohol, polyvinyl chloride, polyvinyl butyral, cellulose esters and blends such as cellulose acetate butyrate, polymers of styrene, butadiene, ethylene, poly carbonates, polymers of vinyl carbonates such as CR39, available from PPG industries, Pittsburgh, and co-polymers of acrylic and allyl carbonate momoners such as BX-946, available form Hampford Research, Stratford, Conn. These polymers can be dissolved, dispersed, ground and deposited in coatings and films that may be formed or applied to media  120  using commonly known processes such as solvent or carrier evaporation, vacuum heat, drying and processing using light. 
     CONCLUSION 
     Although specific embodiments of media and printers have been illustrated and described herein, it is manifestly intended that this invention be limited only by the following claims and equivalents thereof.