CA1278180C - White fluorescent material - Google Patents
White fluorescent materialInfo
- Publication number
- CA1278180C CA1278180C CA000514359A CA514359A CA1278180C CA 1278180 C CA1278180 C CA 1278180C CA 000514359 A CA000514359 A CA 000514359A CA 514359 A CA514359 A CA 514359A CA 1278180 C CA1278180 C CA 1278180C
- Authority
- CA
- Canada
- Prior art keywords
- fluorescent material
- white
- white fluorescent
- emission
- mol
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
- C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
- C09K11/7783—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals one of which being europium
- C09K11/7784—Chalcogenides
- C09K11/7787—Oxides
- C09K11/7789—Oxysulfides
Landscapes
- Chemical & Material Sciences (AREA)
- Inorganic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Luminescent Compositions (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A white fluorescent material containing Y2O2S as a matrix and activators consisting of Tb and Eu both added within the range of 0.05 to 0.3 mol %. The white fluorescent material exhibits neither color shading nor uneven light emission and is readily dispersible.
A white fluorescent material containing Y2O2S as a matrix and activators consisting of Tb and Eu both added within the range of 0.05 to 0.3 mol %. The white fluorescent material exhibits neither color shading nor uneven light emission and is readily dispersible.
Description
~78~8~
S ~ E C I F I C A rr I O N
.
T I T L E
HIT~ FLUOR~SCE~T ~ATERIAL"
BACKGROUND OF T~IE INVEi~TION
Field_of the Invention 'rhis invention involves a white fluorescent material for use in the fluorescent surface of a single tube type kinescope, for example, used to record on color films. iilore specifically, it relates to a white fluorescent material which comprises light-emitting ingredients for red, green and blue colors and e.-nits white light.
Descriptlon of the Prior Art An electron beam exposure system utilizing direct irradiation of electron beams on photographic films for obtaining video images has been previously used as a method for converting video signals into film images. ~owever, this system requires extremely large~scaled equipment for electron beam exposure, including high vacuum equipment having a section for arranging the film and the handling thereof is extremely complicated.
A method of projecting cathode ray tube images on photographic films for exposure has also been proposed as an alternate method. However, it is necessary in this case -to align three different types of images from cathode ray tubes for the red, green and blue colors on a filrn with no deviation.
In the case of a single type kinescope, film images are prepared by using a single tube type white cathode ray tube :,1, !, ~:7~
having a whit~ fluorescent surface in wnich Eluorescent materials of red, green and blue colors ar~ disperseæ. ~eproduced images are developed thereon successively by means of video signals for the respective red, green and blue color ingredients and the thus obtained images are exposed on an identical film by way of filters corresponding to the respective colors while being superimposed successively, thereby obtaining a color image for one frame on the film. This system provides various advantages such as relatively convenient handling for the device and preparation of color lmages with no deviation between the images for each of the colors.
The white fluorescent material of the prior art contains light-emitting fluorescent materials of the constituent color ingredients. These have been prepared by mixing ingredients for blue fluorescent materials such as ZnS : Ag, a green fluorescent material such as ZnS : CuAl, and a red fluorescent material such as Y202S : Eu, all of which have been used in ordinary color television image receiving tubes. However, since these white producing fluorescent materials are prepared by mixing fluorescent materials having diff~rent physical properties such as specific gravity, they have the disadvantage that the dispersibility is poor and the fluorescen-t materials coagulate upon preparation of the fluorescent surface to cause uneven light emission for each of the colors.
SUMMARY OF T~IE INVENTIO~
I'he present invention provides a white Eluorescent makerial free from the problem of dispersibility in the fluorescent material for each of the colors as described above, so that it causes neither shading nor uneven light emission.
~278~
The present invention involves the use of a white fluorescent material comprising a matrix of Y202S and activators of Tb and Eu, both added in a quantity of 0.05 to 0.3 mol %. The total of the two activators is governed by the following general formula:
(Yl_p~qTbpEUq) 22S . ~ .... ( 1 ) the individual values oE p and q are selected to be in the range from 0.05 to 0.3 mol ~ with the further relationship that the sum of p and y is e~ual to or greater than 0.1 and equal to or less than 0.5.
One of the features of the present invention resides in the fact that the white ~luorescent material comprises a single fluorescent material composed of red, green and blue emission ingredients while effecting white emission, and does not consist of a mixture of a plurality of species of ~luorescent materials whereby the problem of dispersibility experienced in the use of a plurality of fluorescent materials in admixture can be overcome completely.
Since the fluorescent material described above is constituted of a single fluorescent material in which a common matrix of Y202S is activated simultaneously with the activators Tb and ~u, the Tb producing green and blue color emission and Eu producincJ red color emission, ~luorescent material with neither shading nor uneven light emission can be obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
.. . . _ . _ Other objects, features and advantages of the presen-t invention will become apparent from the following description ~8~
reFe~ring to ~re~erred embodiments, as illustrated in the accompanying drawings:
FI~. 1 is a chart identifying various compositions coming within the scope of the present invention and some of tneir physical characteristics;
FIGS. 2 through 13 are emission spectra charts for each of the fluorescent materials labeled Samples Nos. 1-12, respectively, in FIG. 1 in that order;
FIG. 14 is a diagrarn plotting the position for each o~
tAe sampies in a chromaticity diagram;
FIG. 15 is a graph plotting relative emission luminance against Eu concentration; and FIG. 16 is a pair of curYes plotting relative luminance against current density.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The fluorescent material according to the present invention can be prepared as follows. Powders of Y2O3, S, Tb407 and Eu2O3 are used as the starting materials and are admixed with sodium carbonate and diammonium phosphate as a flux. The mixture is sintered in an alumina crucible at temperatures ranging from 1000 to 1200C for several hours. After sintering, the desired powdery fluorescent material is obtained by washing to remove excess S, ~la2CO3, (NH4)2HPO~, and the like with hot water. Then, -the luminance characteristics of the thus obtained fluorescent material is measured under electron ray excitation. The measurement is conducted by coating a fluorescent material to be measured to the inner surface of a front panel oE a cathode ray tube with a so-called demandable device detachably disposed to ~2S7~
the main Dody OL the cathode ray tube, then mounting the panel in ar. air-tight man~er to the main tube body. That is, the panel is moonted to the frontal portion and the cathode ray tube is operatea after the evacuation of the tube so that the emission characteristics thereof were measured under normal electron excitation.
Example 1 Y2O3 powder of 99.99% purity and activators consisting of Tb~07 and Eu2O3 were weighed out such that the values for p and q in equation (1) were: p = 0.1, q = 0.05. These materials were milled in alcohol for two hours and then filtered and dried. 30.06 g of S, 52.99 g of Na2CO3 and 4.95 g of (NH4)2HPO4 were mixed with the product thus obtained and these starting materials were put into an alumina crucible and sintered at 1050C for one hour. After sintering, the sintered product was washed with hot water to obtain a powdery fluorescent material.
This material will hereinafter be referred to as sample No. 1.
The powdery fluorescent materials of samples Nos. 2-12, respectively, were also prepared with the same procedures as in Example 1 while varying the respective amounts. The relative amoun~s as well as the p and q values in equation (1) for each of these samples will be set forth below.
FIGS. 2-13 show the emission spectrum diagrams for samples 1-12, respectively, in that order. All of the samples produced red emission at 6200 A, green emission at 5400 A, and blue emission at 4200 and 4400 ~ in common although there were difEerences in intensity. It will be seen from FIG. 1 which sets forth the x and y values of the coordinates of the CIE
chromaticity diagram for each, the various samples being id~nti~Le~l r)y number, that all of them were within a wllite region surrounded by the broken line a in FIG. 14 within the range wherein Tb and Eu each constituted from 0.05 to 0.3 mol %. The emitted light approached red as the Eu concentration was raised. The samples labeled 1, 2, 6, 7 and 8 producing red, green and blue light emissions at relatively high levels in the emlssion spectrum chart can be consiaered as the more ~referred white fluorescent materials. Other samples can also be used Eor the preparation of color film images using them in the kinescope as previously described by selec-ting them wi-th proper variation of exposure time to the film for each of the colors. According to the chart, the Tb concentration is preferably smaller than 0.3 mol ~. If the Tb concentration is adjusted to 0.3 mol ~, it is desirable that the Eu concentration be selected as low as about 0.05 mol %. However, it is necessary to add each of the activators Tb and Eu in amounts more than about 0.05 mol % in order to obtain effective activator function.
Curves (1), (2) and (3~ in FI~. 15 show the results of measurement of the emission luminance relative to the Eu concentration when the Tb concentration is at 0.1, 0.2 and 0.3 mol %. It will be seen that the luminance is lowered as the Eu concentration is increased. Although the usual red fluorescent material Y202S : Eu has a high eMission luminance at an Eu concentration from 2 to 5 mol %, the Eu concentration is lowered to 0.05 to 0.3 mol % fGr the purposes of this invention. This is due to the fact that if the Eu concentration is hiyher the activator function thereof is increased and predominates as compared with that of Tb, thereby hindering the Tb activating effect.
~78~8~
Curve (~) in FI~. 16 shows the current-luminance characteristics of the fluorescent material of sample No. 1 according to this invention. Curve (5) shows the relative luminance for the white fiuorescent material prepared by mixing tne fluore~cent materials for each of the colors, that is, ZnS : Ag, Zn : CuAl and Y202S : Eu as described previously. As apparent from an inspection of curves (4) and (5), there is less saturation in ~he luMinance occurring even at a large current in the composition of the present invnetion.
Since the white fluorescent material according to the present invention emits white color as a whole, by including light emission ingredients of red, green and blue, the composition constitutes a single yttrium rare earth fluorescent material and is free from the problem of dispersibility, ~hile possessing the advantages of causing neither color shading nor uneven luminance.
Accordingly, the fluorescent material according to the present invention can desirably be used as a white fluorescent material on the fluorescent surface of a kinescope.
Further, as described in connection with FIG. 16, since the white fluorescent material according to this invention causes less luminance saturation even at large currents, it can advantageously provide high luminance exposure to photographic films to thereby obtain clear film images.
It will be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention.
,~ .
S ~ E C I F I C A rr I O N
.
T I T L E
HIT~ FLUOR~SCE~T ~ATERIAL"
BACKGROUND OF T~IE INVEi~TION
Field_of the Invention 'rhis invention involves a white fluorescent material for use in the fluorescent surface of a single tube type kinescope, for example, used to record on color films. iilore specifically, it relates to a white fluorescent material which comprises light-emitting ingredients for red, green and blue colors and e.-nits white light.
Descriptlon of the Prior Art An electron beam exposure system utilizing direct irradiation of electron beams on photographic films for obtaining video images has been previously used as a method for converting video signals into film images. ~owever, this system requires extremely large~scaled equipment for electron beam exposure, including high vacuum equipment having a section for arranging the film and the handling thereof is extremely complicated.
A method of projecting cathode ray tube images on photographic films for exposure has also been proposed as an alternate method. However, it is necessary in this case -to align three different types of images from cathode ray tubes for the red, green and blue colors on a filrn with no deviation.
In the case of a single type kinescope, film images are prepared by using a single tube type white cathode ray tube :,1, !, ~:7~
having a whit~ fluorescent surface in wnich Eluorescent materials of red, green and blue colors ar~ disperseæ. ~eproduced images are developed thereon successively by means of video signals for the respective red, green and blue color ingredients and the thus obtained images are exposed on an identical film by way of filters corresponding to the respective colors while being superimposed successively, thereby obtaining a color image for one frame on the film. This system provides various advantages such as relatively convenient handling for the device and preparation of color lmages with no deviation between the images for each of the colors.
The white fluorescent material of the prior art contains light-emitting fluorescent materials of the constituent color ingredients. These have been prepared by mixing ingredients for blue fluorescent materials such as ZnS : Ag, a green fluorescent material such as ZnS : CuAl, and a red fluorescent material such as Y202S : Eu, all of which have been used in ordinary color television image receiving tubes. However, since these white producing fluorescent materials are prepared by mixing fluorescent materials having diff~rent physical properties such as specific gravity, they have the disadvantage that the dispersibility is poor and the fluorescen-t materials coagulate upon preparation of the fluorescent surface to cause uneven light emission for each of the colors.
SUMMARY OF T~IE INVENTIO~
I'he present invention provides a white Eluorescent makerial free from the problem of dispersibility in the fluorescent material for each of the colors as described above, so that it causes neither shading nor uneven light emission.
~278~
The present invention involves the use of a white fluorescent material comprising a matrix of Y202S and activators of Tb and Eu, both added in a quantity of 0.05 to 0.3 mol %. The total of the two activators is governed by the following general formula:
(Yl_p~qTbpEUq) 22S . ~ .... ( 1 ) the individual values oE p and q are selected to be in the range from 0.05 to 0.3 mol ~ with the further relationship that the sum of p and y is e~ual to or greater than 0.1 and equal to or less than 0.5.
One of the features of the present invention resides in the fact that the white ~luorescent material comprises a single fluorescent material composed of red, green and blue emission ingredients while effecting white emission, and does not consist of a mixture of a plurality of species of ~luorescent materials whereby the problem of dispersibility experienced in the use of a plurality of fluorescent materials in admixture can be overcome completely.
Since the fluorescent material described above is constituted of a single fluorescent material in which a common matrix of Y202S is activated simultaneously with the activators Tb and ~u, the Tb producing green and blue color emission and Eu producincJ red color emission, ~luorescent material with neither shading nor uneven light emission can be obtained.
BRIEF DESCRIPTION OF THE DRAWINGS
.. . . _ . _ Other objects, features and advantages of the presen-t invention will become apparent from the following description ~8~
reFe~ring to ~re~erred embodiments, as illustrated in the accompanying drawings:
FI~. 1 is a chart identifying various compositions coming within the scope of the present invention and some of tneir physical characteristics;
FIGS. 2 through 13 are emission spectra charts for each of the fluorescent materials labeled Samples Nos. 1-12, respectively, in FIG. 1 in that order;
FIG. 14 is a diagrarn plotting the position for each o~
tAe sampies in a chromaticity diagram;
FIG. 15 is a graph plotting relative emission luminance against Eu concentration; and FIG. 16 is a pair of curYes plotting relative luminance against current density.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The fluorescent material according to the present invention can be prepared as follows. Powders of Y2O3, S, Tb407 and Eu2O3 are used as the starting materials and are admixed with sodium carbonate and diammonium phosphate as a flux. The mixture is sintered in an alumina crucible at temperatures ranging from 1000 to 1200C for several hours. After sintering, the desired powdery fluorescent material is obtained by washing to remove excess S, ~la2CO3, (NH4)2HPO~, and the like with hot water. Then, -the luminance characteristics of the thus obtained fluorescent material is measured under electron ray excitation. The measurement is conducted by coating a fluorescent material to be measured to the inner surface of a front panel oE a cathode ray tube with a so-called demandable device detachably disposed to ~2S7~
the main Dody OL the cathode ray tube, then mounting the panel in ar. air-tight man~er to the main tube body. That is, the panel is moonted to the frontal portion and the cathode ray tube is operatea after the evacuation of the tube so that the emission characteristics thereof were measured under normal electron excitation.
Example 1 Y2O3 powder of 99.99% purity and activators consisting of Tb~07 and Eu2O3 were weighed out such that the values for p and q in equation (1) were: p = 0.1, q = 0.05. These materials were milled in alcohol for two hours and then filtered and dried. 30.06 g of S, 52.99 g of Na2CO3 and 4.95 g of (NH4)2HPO4 were mixed with the product thus obtained and these starting materials were put into an alumina crucible and sintered at 1050C for one hour. After sintering, the sintered product was washed with hot water to obtain a powdery fluorescent material.
This material will hereinafter be referred to as sample No. 1.
The powdery fluorescent materials of samples Nos. 2-12, respectively, were also prepared with the same procedures as in Example 1 while varying the respective amounts. The relative amoun~s as well as the p and q values in equation (1) for each of these samples will be set forth below.
FIGS. 2-13 show the emission spectrum diagrams for samples 1-12, respectively, in that order. All of the samples produced red emission at 6200 A, green emission at 5400 A, and blue emission at 4200 and 4400 ~ in common although there were difEerences in intensity. It will be seen from FIG. 1 which sets forth the x and y values of the coordinates of the CIE
chromaticity diagram for each, the various samples being id~nti~Le~l r)y number, that all of them were within a wllite region surrounded by the broken line a in FIG. 14 within the range wherein Tb and Eu each constituted from 0.05 to 0.3 mol %. The emitted light approached red as the Eu concentration was raised. The samples labeled 1, 2, 6, 7 and 8 producing red, green and blue light emissions at relatively high levels in the emlssion spectrum chart can be consiaered as the more ~referred white fluorescent materials. Other samples can also be used Eor the preparation of color film images using them in the kinescope as previously described by selec-ting them wi-th proper variation of exposure time to the film for each of the colors. According to the chart, the Tb concentration is preferably smaller than 0.3 mol ~. If the Tb concentration is adjusted to 0.3 mol ~, it is desirable that the Eu concentration be selected as low as about 0.05 mol %. However, it is necessary to add each of the activators Tb and Eu in amounts more than about 0.05 mol % in order to obtain effective activator function.
Curves (1), (2) and (3~ in FI~. 15 show the results of measurement of the emission luminance relative to the Eu concentration when the Tb concentration is at 0.1, 0.2 and 0.3 mol %. It will be seen that the luminance is lowered as the Eu concentration is increased. Although the usual red fluorescent material Y202S : Eu has a high eMission luminance at an Eu concentration from 2 to 5 mol %, the Eu concentration is lowered to 0.05 to 0.3 mol % fGr the purposes of this invention. This is due to the fact that if the Eu concentration is hiyher the activator function thereof is increased and predominates as compared with that of Tb, thereby hindering the Tb activating effect.
~78~8~
Curve (~) in FI~. 16 shows the current-luminance characteristics of the fluorescent material of sample No. 1 according to this invention. Curve (5) shows the relative luminance for the white fiuorescent material prepared by mixing tne fluore~cent materials for each of the colors, that is, ZnS : Ag, Zn : CuAl and Y202S : Eu as described previously. As apparent from an inspection of curves (4) and (5), there is less saturation in ~he luMinance occurring even at a large current in the composition of the present invnetion.
Since the white fluorescent material according to the present invention emits white color as a whole, by including light emission ingredients of red, green and blue, the composition constitutes a single yttrium rare earth fluorescent material and is free from the problem of dispersibility, ~hile possessing the advantages of causing neither color shading nor uneven luminance.
Accordingly, the fluorescent material according to the present invention can desirably be used as a white fluorescent material on the fluorescent surface of a kinescope.
Further, as described in connection with FIG. 16, since the white fluorescent material according to this invention causes less luminance saturation even at large currents, it can advantageously provide high luminance exposure to photographic films to thereby obtain clear film images.
It will be evident that various modifications can be made to the described embodiments without departing from the scope of the present invention.
,~ .
Claims (2)
1. A single white fluorescent material comprising a matrix of Y2O2S and activators of Tb and Eu, each activator being present at a concentration of from 0.05 to 0.3 mol %.
2. A single white fluorescent material according to claim 1 wherein said material has the general formula (Y1-p-qTbpEuq)2O2S
wherein the sum of p + q is equal or greater than 0.1 and equal to or less than 0.5.
wherein the sum of p + q is equal or greater than 0.1 and equal to or less than 0.5.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP16264785A JPS6222888A (en) | 1985-07-23 | 1985-07-23 | White phosphor |
| JP162647/85 | 1985-07-23 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1278180C true CA1278180C (en) | 1990-12-27 |
Family
ID=15758595
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000514359A Expired - Lifetime CA1278180C (en) | 1985-07-23 | 1986-07-22 | White fluorescent material |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS6222888A (en) |
| CA (1) | CA1278180C (en) |
| GB (1) | GB2178050B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0617108A1 (en) * | 1993-03-26 | 1994-09-28 | Eastman Kodak Company | Improved CRT phosphor for the reproduction of color photographs |
| WO2018211829A1 (en) * | 2017-05-15 | 2018-11-22 | 根本特殊化学株式会社 | Afterglowing acid sulfide fluorescent body, and luminescent composition for authentication |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4113648A (en) * | 1974-11-20 | 1978-09-12 | Gte Sylvania Incorporated | Terbium-activated rare earth oxysulfide phosphors with controlled decay |
-
1985
- 1985-07-23 JP JP16264785A patent/JPS6222888A/en active Pending
-
1986
- 1986-07-22 GB GB8617883A patent/GB2178050B/en not_active Expired
- 1986-07-22 CA CA000514359A patent/CA1278180C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6222888A (en) | 1987-01-31 |
| GB8617883D0 (en) | 1986-08-28 |
| GB2178050A (en) | 1987-02-04 |
| GB2178050B (en) | 1989-04-05 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |