Radiation imagery chemistry: process – composition – or product th – Radiation modifying product or process of making – Screen other than for cathode-ray tube
Reexamination Certificate
2000-07-21
2002-03-19
McPherson, John A. (Department: 1756)
Radiation imagery chemistry: process, composition, or product th
Radiation modifying product or process of making
Screen other than for cathode-ray tube
C313S504000
Reexamination Certificate
active
06358652
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a fluorescent conversion filter that converts light, emitted by a light-emitting device, in near ultraviolet to visible region light to light in different visible region. The invention also relates to an organic light-emitting device equipped with a fluorescent conversion filter. The fluorescent conversion filter and the organic light-emitting device are applicable to both consumer and industry display apparatuses such as a self-emitting multicolored or full colored-display, a display panel, and a backlight.
Increasing demand for flat panel displays to replace conventional cathode ray tube (CRT) displays, has promoted active development and practical application of various display devices. An electroluminescent device (hereinafter referred to as light-emitting device) is one of the devices created to meet the demand. The light-emitting device has received attention as an all solid state self light-emitting device. The light-emitting device exhibits high resolution and high visibility not readily attained by other display devices.
In a known method for multi-colored or full-colored displays, such as a flat panels, organic light-emitting elements corresponding to the three primary colors of red, blue and green are separately arranged in a matrix form and each of them is caused to emit light. This method is disclosed by Japanese Unexamined Patent Application Publication Nos. S57-157487, S58-147989 and H3-214593. However, the color display using an organic light-emitting device requires precise matrix arrangement of three kinds of light-emitting material for red, blue and green. The technology for this arrangement is difficult and costly to manufacture. Additionally, the chromaticity gradually deviates because the lifetime of the three light-emitting materials differs each other.
In another known method for color display, white light emitted from a backlight is passed through filters and three primary colors are obtained. This method is disclosed by Japanese Unexamined Patent Application Publication Nos. H1-315988, H2-273496 and H3-194895. However, to attain red, green and blue light of high brightness a white-light-emitting device requires high brightness. A white-light emitting device exhibiting both a long life and high brightness has not been obtained yet.
In another known method for color display, fluorescent elements separately arranged in a plane, absorb light from a light-emitting body and each of the fluorescent elements emits multi-colored fluorescent light. This method is disclosed by Japanese Unexamined Patent Application Publication No. H3-152897. This method uses a light-emitting body and fluorescent elements to create multi-colored fluorescent light. This method applied to CRT and plasma display.
In recent years, a color conversion method has been developed in which fluorescent material is used as a filter. The fluorescent material absorbs light from an organic light-emitting element and emits fluorescent light in a visible light region. This method is disclosed by Japanese Unexamined Patent Application Publication Nos. H3-152897 and H5-258860. In this method, the color of the light emitted from the organic light-emitting element is not limited to white light. This method allows use of a brighter organic light-emitting element as a light source. In an example of the color conversion method using an organic light-emitting element emitting blue light, wave length conversion is performed from blue light to green light or to red light. This example is disclosed by Japanese Unexamined Patent Application Publication Nos. H3-152897, H8-286033 and H9-208944.
Organic fluorescent dyes such as rhodamine dye, pyridine dye, oxadine dye and coumarin dye are used for the fluorescent material described above. This use is disclosed by Japanese Unexamined Patent Application Publication Nos. H8-78158, H8-222369, H8-279394, H8-286033, H9-106888, H9-208944, H9-245511, H9-330793 and H10-12379.
Where low energy rays, such as radiation in a near ultraviolet to visible light region, from an organic light-emitting element are used, a full-colored self-emitting display device could be constructed by precisely patterning a fluorescent conversion filter containing such organic fluorescent dye.
There are two methods, among the known methods, for patterning a fluorescent conversion filter. In the first method, similar to the case of inorganic fluorescent material, an organic fluorescent dye is dispersed in a liquid photoresist that is a photo-reactive polymer. The resulting material is then laminated by spin-coating, followed by patterning by means of photolithography. This method is disclosed by Japanese Unexamined Patent Application Publication Nos. H5-198921 and H5-258860.
In the second method, organic fluorescent dye or organic fluorescent pigment is dispersed in a basic binder. The resulting article is then etched by acidic aqueous solution. This method is disclosed by Japanese Unexamined Patent Application Publication No. H9-208944.
The first above-described method of patterning, by means of photolithography, raises a problem where organic fluorescent dye is dispersed in a liquid photoresist. Since the liquid photoresist contains a photopolymerizaion agent, an agent for thermosetting (or polymerization initiator), and a reactive multifunctional monomer or oligomer, decomposition and quenching of the organic dye often occur. Decomposition and quenching of the organic dye can occur due to radicals originated from the photopolymerization initiator or due to propagation radicals of the reactive multifunctional monomer.
The second above-described method of patterning, by means of an acidic aqueous solution, raises a problem when photoresist is coated on the fluorescent conversion filter comprised of a basic binder and later followed by patterning. Since manufacturing a filter requires many steps cost and time are increased. Additionally, as a further disadvantage, this method creates a narrowing of the pattern, caused by side etching.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the invention to provide a fluorescent conversion filter that facilitates controlling the radicals originated from the photopolymerization initiator and the propagation radicals of reactive multifunctional monomer in the photolithography process. This will suppress decomposition and quenching of the fluorescent dye.
It is another object of the invention to provide an organic light-emitting device having such a fluorescent conversion filter.
An organic light-emitting device may be equipped with a fluorescent conversion filter which suppresses decomposition and quenching of fluorescent dyes or pigments. The fluorescent conversion filter is formed by coating with a coating material, followed by patterning by photolithography. The coating material consists of a mixture of organic fluorescent dye or pigment that absorbs light in the ultraviolet to visible light region. The coating also includes a photo-setting or photo-and-thermo-setting resin containing a photopolymerizaion initiator of a hydrogen abstraction type having a benzophenone skeleton within the molecule. As a result, an organic light-emitting device is produced by combining the a fluorescent conversion filter with an organic light-emitting element.
According to an embodiment of the invention, there is provided a fluorescent conversion filter comprising: an organic fluorescent dye or an organic fluorescent pigment that absorbs light in a near ultraviolet to visible light region emitted from a light-emitting element, the organic fluorescent dye or pigment emitting different visible light, a matrix resin bearing the organic fluorescent dye or pigment, the resin matrix being a photo-setting resin or a photo-and-thermo-setting resin containing a photopolymerization initiator, the photopolymerization initiator of a hydrogen abstract type, the photopolymerization initiatory having a benzophenone skeleton represented by the following general formula (I) or (II):
Wherein each of R
1
through R
10
, i
Kobayashi Ryoji
Shiraishi Yotaro
Tomiuchi Yoshimasa
Fuji Electric & Co., Ltd.
McPherson John A.
Morrison Law Firm
LandOfFree
Fluorescent conversion filter and organic light-emitting... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fluorescent conversion filter and organic light-emitting..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fluorescent conversion filter and organic light-emitting... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2847916