Radiation imagery chemistry: process – composition – or product th – Color imaging process – Forming combined chromatic and achromatic images
Reexamination Certificate
2002-07-16
2003-10-28
Schilling, Richard L. (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Color imaging process
Forming combined chromatic and achromatic images
C430S432000, C430S434000, C430S021000, C430S139000, C430S503000, C430S510000, C430S512000, C430S519000, C430S520000, C430S521000, C430S522000, C430S523000, C430S508000, C430S933000
Reexamination Certificate
active
06638696
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to producing a photographic image that may be, upon excitation with ambient light, visible in the dark. The photographic image is developed on a display element that contains at least one silver halide emulsion layer and a phosphorescent material.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 4,543,308 describes a photosensitive photographic recording material which contains at least one layer comprising photosensitive silver halide and at least one compound capable of luminescence, whereby the recording material is exposed imagewise and developed resulting in a silver image and a latent luminescent image superimposed on the silver image. U.S. Pat. No. 3,107,138 describes a recording oscillograph in which the recording medium includes silver halide in combination with one or more fluorescent, phosphorescent, and/or heat sensitive materials. By this means a record is obtained which becomes immediately visible due to the action of the fluorescent, phosphorescent, or heat sensitive material and which record remains permanently visible due to the action of the silver halide. There is additionally a large body of patent literature which describes radiographic elements which contain phosphorescent materials or comprise phosphor screens; however, the purpose of the phosphorescent materials in the radiographic elements is to expose the silver halide upon excitation by x-rays. None of these photographic materials are intended for use as glow-in-the-dark materials. Rather, the fluorescent or phosphorescent materials are excited by the electromagnetic radiation used to expose the silver halide.
U.S. Pat. No. 4,745,286 discloses a self-supporting sheet of phosphorescent material, suitable for subsequent use as wallpaper, capable of producing a photographic image that will glow in the dark. The exposure necessary for creating the latent image in an emulsion layer, however, may cause excitation of the phosphorescent layer and thereby result in unwanted exposure to the emulsion. The result is a poorer quality photographic image. U.S. Pat. Nos. 6,071,855 and 5,965,242 describe a medium comprising a phosphorescent layer having a phosphorescent material and an image receiving layer disposed over the phosphorescent layer. The image receiving layer is substantially translucent and capable of retaining an image from a digital printer, more specifically an inkjet printer. These two patents do not involve a silver halide system.
It is still desired to provide a glow-in-the-dark display material that has a high quality photographic image.
SUMMARY OF THE INVENTION
This invention provides a display element comprising a support, a phosphorescent material, and at least one layer containing a silver halide emulsion, wherein the phosphorescent material is not excited upon exposure of the silver halide emulsion. In one embodiment this invention provides a display element comprising a support, a phosphorescent material, and at least one layer containing a silver halide emulsion, wherein the display element also comprises a filter dye which absorbs electromagnetic energy at wavelengths which excite the phosphorescent material, said filter dye being contained in a layer above the phosphorescent material. In another embodiment this invention provides a display element comprising a support, a phosphorescent material, and at least one layer containing a silver halide emulsion, wherein the silver halide emulsion is primarily sensitive to electromagnetic energy at wavelengths which do not excite the phosphorescent material.
This invention also provides a method of exposing and processing a display element which will glow in the dark comprising providing a display element comprising a support, a phosphorescent material, and at least one layer containing a silver halide emulsion; wherein said display element also comprises a filter dye which filters electromagnetic energy at wavelengths which excite the phosphorescent material, said filter dye being contained in a layer above the phosphorescent material; exposing said photographic element to form a latent image; and processing said exposed photographic element in a manner which will develop the latent image and remove the filter dye. It further provides a method of exposing and processing a display element which will glow in the dark comprising providing a display element comprising a support, a phosphorescent material, and a layer containing a silver halide emulsion, said silver halide emulsion being primarily sensitive to electromagnetic energy at wavelengths which do not excite the phosphorescent material; exposing said photographic element to a light source which will cause the silver halide emulsion to form a latent image but which will not excite the phosphorescent material; and processing said exposed photographic element in a manner which will develop the latent image.
This invention provides a novel photographic print media capable of being viewed in the dark after excitation of the phosphor(s). Said image is improved over the prior art by reducing the unwanted exposure to the emulsion from the excited phosphor(s), thereby resulting in a sharper image. The display element of the invention provides a novel photographic print media that can be used in current photographic print systems. In one embodiment the phosphor(s) are coated onto a support without admixing into the support material. This allows for use of a common support for various types of display materials and limits any negative interaction between the support components and the phosphorescent material.
DETAILED DESCRIPTION OF THE INVENTION
The display element of the invention comprises a support, a phosphorescent material, and at least one layer containing a silver halide emulsion, and meets the criteria that the phosphorescent material is not substantially excited upon exposure of the silver halide emulsion to form a latent image. This minimizes unwanted exposure to the photographic emulsion due to phosphorescence and results in a sharper image. This may be accomplished in one of two main fashions. The first is to use filter dyes as a means to avoid excitation of the phosphor(s) during the photographic exposure. The second is to use photographic emulsions sensitized to electromagnetic energy bands that will not excite the phosphor layer to create the photographic image.
In the following discussion, the term “above” will mean closer to any intended source of electromagnetic energy used to expose the silver halide emulsion, and the term “below” will mean further from any intended source of electromagnetic energy used to expose the silver halide emulsion. The phosphorescent material may be contained in either the support or in a layer above or below the support. It is anticipated that generally the phosphorescent material will be contained in either the support or in a layer above the support (i.e., between the support and the intended source of exposure), particularly when the support of the display element is opaque. However, in the situation where the support is transparent, the phosphorescent material may also be contained in a layer below or behind the support, i.e., the support is between the phosphorescent material and the intended exposure source. From the intended use of the display material it will be clear to those skilled in the art that any layers of the display material which are between the layer comprising the phosphorescent material and any intended viewer of the glow-in-the-dark display will be translucent or transparent so as not to interfere with the glow-in-the-dark effect.
Preferably the phosphorescent material is contained in a layer separate from the support. The separate layer containing the phosphorescent material preferably also contains a binder such as gelatin or some other polymer, or a mixture thereof. The gelatin may be any number of commercially available gelatins that are well known to those skilled in the art. The polymer may be AQ55, available from Eastman Chemical Corporation. Another polymer may be an acrylic latex such
Meeks Roberts Sarah
Schilling Richard L.
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