Abstract:
A method of tailoring the shape of a plurality of relief printing dots created in a photosensitive printing blank during a platemaking process is provided. The photocurable layer is exposed to actinic radiation using an array of UV LED light assemblies and the use of the array of UV LED light assemblies produces relief printing dots having at least one geometric characteristic selected from the group consisting of a desired planarity of a top surface of the relief printing dots, a desired shoulder angle of the relief printing dots and a desired edge sharpness of the relief printing dots.
Abstract:
A method of making a relief image printing element from a photosensitive printing blank is provided. A photosensitive printing blank with a laser ablatable layer disposed on at least one photocurable layer is ablated with a laser to create an in situ mask. The printing blank is then exposed to at least one source of actinic radiation through the in situ mask to selectively cross link and cure portions of the photocurable layer. Diffusion of air into the at least one photocurable layer is limited during the exposing step and preferably at least one of the type, power and incident angle of illumination of the at least one source of actinic radiation is altered during the exposure step. The resulting relief image comprises a plurality of dots and a dot shape of the plurality of dots that provide optimal print performance on various substrates, including corrugated board.
Abstract:
A method and apparatus for printing a pattern of periodic features into a photosensitive layer, including the steps of providing a substrate bearing the layer, providing a mask, arranging the substrate such that it has a tilt angle with respect to the substrate in a first plane orthogonal thereto, providing collimated light for illuminating the mask pattern so as to generate a transmitted light-field composed of a range of transversal intensity distributions between Talbot planes separated by a Talbot distance, and so that said transmitted light-field has an intensity envelope in the first plane, illuminating the mask with said light whilst displacing the substrate relative to the mask in a direction parallel to the first plane and to the substrate, wherein the tilt angle and the intensity envelope are arranged so that the layer is exposed to an average of the range of transversal intensity distributions.
Abstract:
A method of making a relief image printing element from a photosensitive printing blank is provided. A photosensitive printing blank with a laser ablatable layer disposed on at least one photocurable layer is ablated with a laser to create an in situ mask. The printing blank is then exposed to at least one source of actinic radiation through the in situ mask to selectively cross link and cure portions of the photocurable layer. Diffusion of air into the at least one photocurable layer is limited during the exposing step and preferably at least one of the type, power and incident angle of illumination of the at least one source of actinic radiation is altered during the exposure step. The resulting relief image comprises a plurality of dots and a dot shape of the plurality of dots that provide optimal print performance on various substrates, including corrugated board.
Abstract:
The present invention solves the stitching problem and the problem of a predetermine integer number of grating lines per closed circle of a cylindrical grating by resorting to a novel phase mask method which proposes to geometrically transform and to optically transfer a standard planar radial grating pattern (1) into a cylindrical photoresist pattern (9) at the circularly cylindrical wall (7) of a given element (3). The planar radial grating pattern can be easily written with an integer number of lines having strictly constant period without any stitching problem by means of the available tools of planar technologies such as a laser or electron beam generator and reactive ion etching. The photolithographic transfer is made by illumination means (19) which permit the needed geometrical transformation from a planar radial grating to a circularly cylindrical grating, in particular by providing a cylindrical wave having a non-zero axial component and the same central axis (A) as said circularly cylindrical wall or a spherical wave (B) with its center on this central axis.
Abstract:
A method of fabricating an optical element including a liquid crystal layer having a spatially-varying tilt angle includes coating a substrate with a linearly photopolymerizable polymer layer, irradiating the linearly photopolymerizable polymer layer with linearly polarized ultra-violet light at a oblique angle, and coating a layer of liquid crystal material on a surface of the irradiated linearly photopolymerizable polymer layer. The liquid crystal material has a predetermined relationship between its tilt angle and a total dose of the linearly polarized ultra-violet light. The linearly photopolymerizable polymer layer is irradiated with at least one dose of linearly polarized ultra-violet light that is sufficient to induce formation of a plurality of discrete regions within the liquid crystal layer having a larger in-plane birefringence than an adjacent or surrounding region.
Abstract:
What is described is a lithographic method for fabricating three-dimensional structures on the micrometric and submicro-metric scale, including the operations of: - depositing a layer (L1) of a first resist (R1) on a substrate (S); - depositing a layer (L') of a second resist (R2) on the layer (L1) of the first resist (R1); - forming a pattern of the second resist (R2) by lithography; - depositing a further layer (L2) of the first resist (R1) on the previous layers; and - forming a pattern of the first resist (R1) by lithography. The second resist (R2) is sensitive to exposure to charged particles or to electromagnetic radiation in a different way from the first (R1); in other words, it is transparent to the particles or to the electromagnetic radiation to which the first resist (R1) is sensitive, and therefore the processes of exposure and development of the two resists (R1, R2) are mutually incompatible to the extent that the exposure and development of one does not interfere with the exposure and development of the other.
Abstract:
Disclosed are methods for making large area antiscatter grids consisting of focussed and unfocussed holes in sheets of metal. The grid consists of thin metal walls (30) surrounding hollow openings (31). The projections of all walls converge to a focal spot in the focussed grid, and are parallel in an unfocussed grid. A grid having a large area is made by interlocking together smaller grid pieces. A tall device is made by stacking layers of focussed grids. The openings of the grid can be filled with phosphor or other scintillating material (33) to make an integrated grid/scintillator structure.