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AssigneeE. I. Du Pont de Nemours and Company
InventorsGerald D. Andrews, Jonathan V. Caspar
Estimating the term…
A process for making a radiation filter element comprises the steps of: exposing part of an assemblage to infrared radiation, the assemblage comprising a donor comprising (1) a support capable of transmitting infrared light, and (2) a transferable layer comprising a transferable material and an infrared-absorbing dye, the transferable layer of the donor being in contact with a receiver to provide an exposed assemblage comprising an exposed part of the transferable layer and an unexposed part of the transferable layer; separating the receiver and the support of the exposed assemblage to obtain an imaged receiver and a spent donor, wherein the imaged receiver comprises the receiver, a transferred portion of the transferable material and a transferred portion of the infrared-absorbing dye, said transferred portion of the IR dye having a color and the spent donor comprises the support and a retained portion of the transferable layer; and heating the transferred portion of the transferable material and the transferred portion of the infrared-absorbing dye at a temperature ranging from about 100 degrees Celsius to about 350 degrees Celsius for a period of time sufficient to thermally decolorize 50% to 100% of the transferred portion of the infrared-absorbing dye, the heating being in the absence of a thermal bleaching agent to provide a radiation filter element suitable for use in a liquid crystal display. Preferably color filter elements of this invention are used in liquid crystal display devices.
A method for making a radiation filter element, comprising the steps of:
A method for making a monochrome or color filter element suitable for use in a liquid crystal display device, comprising the steps of:
Dependencies are inferred from the claim text.
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Characterised by the base backcoat, intermediate, or covering layers, e.g. for thermal transfer dye-donor or dye-receiver sheets; Heat,…
Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used: for the production…
Contact thermal transfer or sublimation processes: characterised by aspects not provided for in groups B41M5/385 - B41M5/395
Contact thermal transfer or sublimation processes: characterised by the use of an intermediate receptor
Term ended 7 Jul 2023 (estimated)
This invention relates to a monochrome or color filter array element. More particularly this invention relates to display devices incorporating the monochrome or color filter array element such as liquid crystal displays.
Thermal transfer processes that selectively impinge radiation on a layer to transfer a material such as a colorant to a receiver are known. Lasers are useful sources of such radiation, particularly infrared lasers, which are readily available, easily used, and powerful. Thermal transfer processes are imaging processes used in applications such as color proofing, electronic circuit manufacture, monochrome and color filters, and lithography.
Monochrome and color filters are useful for liquid crystal display devices such as flat panel display devices. Liquid crystal display devices are known for digital display in electronic calculators, clocks, household appliances, audio and visual equipment, etc.
Embodiments of the present invention comprise: a thermally-imageable assemblage comprising a donor with a transferable infrared-absorbing dye and a first receiver; an imaging process that causes heating and transfer of an unchanged portion of the infrared-absorbing dye to the first receiver; and heating of the transferred and unchanged portion of the infrared-absorbing dye to thermally decolorize a fraction (greater than 0.5 and less than or equal to 1) of the transferred infrared-absorbing dye.
The invention uses an assemblage of a donor and a receiver suitable for thermal imaging. The donor can be a complex multilayer structure as is known in the art, comprising a support and a material to be transferred. The support may optionally comprise any one or more of: a base layer, a radiation to heat conversion layer; a release layer; an ejection layer; an adhesive layer and other layers of materials as known in the art.
The base layer of the support serves at least two functions: to provide a surface holding other layers, and to transmit a portion of infrared radiation during the exposure step. The base layer may comprise a dimensionally stable, flexible, sheet material. Examples of transparent, flexible films appropriate for use as the base layer include, for example, films of polyesters (such as polyethylene terephthalate), polyether sulfone, polyimides, poly(vinyl alcohol-co-acetal), polyethylenes, or cellulose esters, such as cellulose acetate, and polyvinyl chloride. In one embodiment, the base layer of the donor support is polyethylene terephthalate that has been plasma treated. Other materials can be present as additives in the base layer, as long as they do not interfere with the essential function of the support. Examples of such additives include plasticizers, coating aids, flow additives, slip agents, antihalation agents, antistatic agents, surfactants, and others which are known for use in the formulation of films. The base layer generally has a thickness in the range of 5–200 microns, preferably 38–102 microns.