CA1110054A - Cerium activated phosphor and method of making same - Google Patents
Cerium activated phosphor and method of making sameInfo
- Publication number
- CA1110054A CA1110054A CA304,420A CA304420A CA1110054A CA 1110054 A CA1110054 A CA 1110054A CA 304420 A CA304420 A CA 304420A CA 1110054 A CA1110054 A CA 1110054A
- Authority
- CA
- Canada
- Prior art keywords
- mixture
- fluoride
- sintering
- oxide
- mols
- 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
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
- C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
- C09K11/7767—Chalcogenides
-
- 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
- C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
- C09K11/7774—Aluminates
-
- 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
- C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
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 luminescent material having an improved ratio of peak intensity to decay time and excitable by an electron beam, the material being prepared by providing a mixture of yttrium oxide, aluminum oxide, gallium oxide, cerium oxide, and all inorganic fluoride which decomposes to liberate fluorine at the sintering temperature of the mixture, and sintering the mixture to produce a material having a higher peak intensity than results from the sintering of the mixture in the absence of the fluoride.
-i-
A luminescent material having an improved ratio of peak intensity to decay time and excitable by an electron beam, the material being prepared by providing a mixture of yttrium oxide, aluminum oxide, gallium oxide, cerium oxide, and all inorganic fluoride which decomposes to liberate fluorine at the sintering temperature of the mixture, and sintering the mixture to produce a material having a higher peak intensity than results from the sintering of the mixture in the absence of the fluoride.
-i-
Description
~1103S4 B~CK GROUND_OF THE INVENTION
FIELD OF THE INVENTION
____ _ _ _ __ This invelltion relates to a pho~phor used in a cathode ray tube, for example7 a beam indexing color cathode ray tu~e, or a flying spot scanner tube and being esenti~1y a cerium activated yttrium aluminum gallium oxide material which has been activated by rneans of an inorganic fluoride.
OESCRIPIlON OF THE_RIOR ART
It is desirable for a phosphor used in a cathode ray tube to have a high peak intensity of emission and a short decay time in order to obtain a beam indexing signal in a beam inde~ing color cathode ray tube or in a flying spot scanner tube. Generally speaking, the shorter the decay time of a phospllor, the lower its peak intensity and the higher the pcak intensity7 thé longer he decay time.
It is well known that a cerium activated phospllor containing -yttrium, for example, Y3A15012:Ce has a relatively high peak intensity and a long life. The cerium activated phospllor having the following formula:
Y3Al3Ga2l2~ e has a relatively high peak intensity and a shorter decay time than the cerium activated pllosphor containing no gallium SUMMARY OF THE_I_VENIION
The present invention provides a means for improving the ratio of peak intensity (PH) to decay time (t) and a lligher absolute peak intensity than previously available cerium activated yttrium -~5~
aluminum gallium oxide phosphors. In summary, the new phosphor is produced by providing a mixture of yttrium oxide, aluminum oxide, gallium oxide, cerium oxide, and an inorganic fluoride which is preferably either barium fluoride or ammonium difluoride, and heating the mixture under sealed conditions to a sintering temperature to produce a material having a higher peak intensity than results from the sintering mixture in the absence of the fluoride. The fluoride acts as a flux at sintering temperatures.
The fluoride is present in an amount of from 1 to 50 mols for every 100 mols of the remainder of the mixture, and preferably from 2.5 to 40 mols per 100 mols. The sintering temperature ranges from about 1400 to 1700C for periods of time ranging from 1 to 6 hours. Particularly good results are obtained when the mixture is sintered at 1500 to 1600C for from 2 to 4 hours.
More particularly, there is provided a method of manufacturing a luminescent material excitable by an electron beam and consisting essentially of cerium activated yttrium aluminum gallium oxide crystals of the form Y3 Alx Gay 12:CE
whereas X+Y=5, X=l to 4, Y=4 to 1 comprising the steps of providing a mixture of yttrium oxide, aluminum oxide, gallium oxide, cerium oxide and an inorganic fluoride which melts to liberate fluorine at the sintering temperature of said mixture, and heating said mixture under sealed conditions to a sintering temperature and sintering the mixture to produce a material having a higher ratio of peak intensity to decay time than results from the sintering of said mixture in the absence of said fluoride.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plot of the relative peak intensity of emission against the concentration of barium fluoride at various aluminum to gallium molecular ratios;
lllQQS~
FIG 2 is a plot of decay time against the concentration of barium fluoride at various ratios of aluminum to gallium molar concentration; and 1~ IG 3 is a plot: of the relative ratio of peak intensity of emission to the decay time against the concentration of barium fluoride present at various aluminum to gallium molar ratios.
DESCRIP~ON OF THE PREFERRED EMBODIMENTS
In accordance with the present invention, we prepare a phosphor composition having a higher peak intensity of emission and shor-er decay times than heretofore common in cerium activated yt~rium aluminum gallium oxide phosphors.
The method involves tlle steps of mixing raw materials to produce a mixture having the following generic formula:
Y3AIXGayl2:Ce where x ~ y = 5 x = 1 t~ 4 y= 4 to 1 The reaction mixture comprises yttrium oxide, aluminum oxide, gallium oxide, and cerium o~iide together with an inorganic fluoride compound such as barium fluoride or ammonium difluoride The fluoride compound is present in an amount of from 1 to 50 mols per 100 mols of the remainder of the mixture and more preferably at 2. 5 to 40 mols per 100 mols of the remaining mixture. The mixture is then sintered at temperatures ranging from about 1400 to 1700~C at times ranging from 1 to 6 hours. This treatment schedule is effective to decrease the decay time. Where the peak intensity is to be increased and the decay time decreased, a treatment at 1500 to 1600C for from 2 to 4 hours is definitely preferred.
At the sintering temperature, barium fluoride melts and ammonium difluoride sublimates. The melt or vapor reacts on the mixture as a flux providing improved mobility for the atoms, promoting the formation of phosphor crystals withou~ defects which cause heat loss. ~he barium and ammonium cations are sufficien~ly large so that they do no~ appear in the crystal lattice of the final produc~.
111~54 The following specific example illustrates the preparation oE the improved pllospllors o~ the presen; invention.
EXAM LE
A cerium activated phosphor having the formula:
Y3AI3Ga212 Ce is made up of raw materials comprising yttrium oxide (3/2 x 0. 98 mol), aluminum oxide (3/2 mol), gallium oxide (1 mol) and cerium oxide (3/2 x 0. 02 mol). These raw materials are combined with 0.1 to 0. 2 mol of barium fluoride and mixed in a ball mill using ethyl alcollol as a solvent. Next the mixture is dried at 80"C, and then heated in an alumina crucible with a sealed lid in place in air at 1550~ for 2 to 4 hour s.
The sintering produces some barium aluminate by the reaction of barium fluoride and alumina, along with some flurine gas.
The barium aluminate may be eliminated by washing with water or acid, and the fluorine gas is volatilized.
The pcalc intensity of the phosphor produced according to this example was more ~han 2 times as high as was observ~d in the case of the cerium activated phosphor which had not been sintered in the presence of the fluoride. Moreover, the decay time which is the time that the emissiYe intensity decays to û. 1 of the peak intensity, was measured to be 110 nanoseconds in the case of the phosphor produ^ed according to the example, whereas a phospllor which is prepared without the fluoride compound evidenced a decay time of 120 nanoseconds. Thus, in accordance with the present invention, the peak intensity is increased and th2 decay time is decreased so that the ratio of pealc intensity to decay time is substantially increased.
?54 The relationship bctween the relative peal~ intensity and the decay time to the concentration of barium fluoride is shown in FIGS.
1 and 2 of the drawings. In FIGS. 1 and 2, the ~bscissae refer to the molar concentration of barium fluoride. As shown in these two Figures, when the concentration of the barium compound is between 1 and 50 mol percent, preferably between 2. 5 and 40 mol percent, the relative peak intensity and the dccay time are improved.
The ratio of the relative peak intensity to the deca~r time is plotted as a function of the concentration of barium fluoride in FIG
3. It is apparent from this Figure that the phosphor has optimum properties by using a concentration of barium fluoride or other fluoride between 1 and 50 mol percent. Since the phosphor produced according to the present invention has characteristics of higher peak intensity oE emission and shorter decay time than those of the conventional phospllor, it can conveniently be used as a phosphor in a beam indexing color cathode ray tube or in a flying spot scanner tube.
Although the invention has been described in connection with preferred embodiments, it is not to be so limited as changes and modifications can be made which are within the full intended scope as de~ined by the appended claims.
FIELD OF THE INVENTION
____ _ _ _ __ This invelltion relates to a pho~phor used in a cathode ray tube, for example7 a beam indexing color cathode ray tu~e, or a flying spot scanner tube and being esenti~1y a cerium activated yttrium aluminum gallium oxide material which has been activated by rneans of an inorganic fluoride.
OESCRIPIlON OF THE_RIOR ART
It is desirable for a phosphor used in a cathode ray tube to have a high peak intensity of emission and a short decay time in order to obtain a beam indexing signal in a beam inde~ing color cathode ray tube or in a flying spot scanner tube. Generally speaking, the shorter the decay time of a phospllor, the lower its peak intensity and the higher the pcak intensity7 thé longer he decay time.
It is well known that a cerium activated phospllor containing -yttrium, for example, Y3A15012:Ce has a relatively high peak intensity and a long life. The cerium activated phospllor having the following formula:
Y3Al3Ga2l2~ e has a relatively high peak intensity and a shorter decay time than the cerium activated pllosphor containing no gallium SUMMARY OF THE_I_VENIION
The present invention provides a means for improving the ratio of peak intensity (PH) to decay time (t) and a lligher absolute peak intensity than previously available cerium activated yttrium -~5~
aluminum gallium oxide phosphors. In summary, the new phosphor is produced by providing a mixture of yttrium oxide, aluminum oxide, gallium oxide, cerium oxide, and an inorganic fluoride which is preferably either barium fluoride or ammonium difluoride, and heating the mixture under sealed conditions to a sintering temperature to produce a material having a higher peak intensity than results from the sintering mixture in the absence of the fluoride. The fluoride acts as a flux at sintering temperatures.
The fluoride is present in an amount of from 1 to 50 mols for every 100 mols of the remainder of the mixture, and preferably from 2.5 to 40 mols per 100 mols. The sintering temperature ranges from about 1400 to 1700C for periods of time ranging from 1 to 6 hours. Particularly good results are obtained when the mixture is sintered at 1500 to 1600C for from 2 to 4 hours.
More particularly, there is provided a method of manufacturing a luminescent material excitable by an electron beam and consisting essentially of cerium activated yttrium aluminum gallium oxide crystals of the form Y3 Alx Gay 12:CE
whereas X+Y=5, X=l to 4, Y=4 to 1 comprising the steps of providing a mixture of yttrium oxide, aluminum oxide, gallium oxide, cerium oxide and an inorganic fluoride which melts to liberate fluorine at the sintering temperature of said mixture, and heating said mixture under sealed conditions to a sintering temperature and sintering the mixture to produce a material having a higher ratio of peak intensity to decay time than results from the sintering of said mixture in the absence of said fluoride.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plot of the relative peak intensity of emission against the concentration of barium fluoride at various aluminum to gallium molecular ratios;
lllQQS~
FIG 2 is a plot of decay time against the concentration of barium fluoride at various ratios of aluminum to gallium molar concentration; and 1~ IG 3 is a plot: of the relative ratio of peak intensity of emission to the decay time against the concentration of barium fluoride present at various aluminum to gallium molar ratios.
DESCRIP~ON OF THE PREFERRED EMBODIMENTS
In accordance with the present invention, we prepare a phosphor composition having a higher peak intensity of emission and shor-er decay times than heretofore common in cerium activated yt~rium aluminum gallium oxide phosphors.
The method involves tlle steps of mixing raw materials to produce a mixture having the following generic formula:
Y3AIXGayl2:Ce where x ~ y = 5 x = 1 t~ 4 y= 4 to 1 The reaction mixture comprises yttrium oxide, aluminum oxide, gallium oxide, and cerium o~iide together with an inorganic fluoride compound such as barium fluoride or ammonium difluoride The fluoride compound is present in an amount of from 1 to 50 mols per 100 mols of the remainder of the mixture and more preferably at 2. 5 to 40 mols per 100 mols of the remaining mixture. The mixture is then sintered at temperatures ranging from about 1400 to 1700~C at times ranging from 1 to 6 hours. This treatment schedule is effective to decrease the decay time. Where the peak intensity is to be increased and the decay time decreased, a treatment at 1500 to 1600C for from 2 to 4 hours is definitely preferred.
At the sintering temperature, barium fluoride melts and ammonium difluoride sublimates. The melt or vapor reacts on the mixture as a flux providing improved mobility for the atoms, promoting the formation of phosphor crystals withou~ defects which cause heat loss. ~he barium and ammonium cations are sufficien~ly large so that they do no~ appear in the crystal lattice of the final produc~.
111~54 The following specific example illustrates the preparation oE the improved pllospllors o~ the presen; invention.
EXAM LE
A cerium activated phosphor having the formula:
Y3AI3Ga212 Ce is made up of raw materials comprising yttrium oxide (3/2 x 0. 98 mol), aluminum oxide (3/2 mol), gallium oxide (1 mol) and cerium oxide (3/2 x 0. 02 mol). These raw materials are combined with 0.1 to 0. 2 mol of barium fluoride and mixed in a ball mill using ethyl alcollol as a solvent. Next the mixture is dried at 80"C, and then heated in an alumina crucible with a sealed lid in place in air at 1550~ for 2 to 4 hour s.
The sintering produces some barium aluminate by the reaction of barium fluoride and alumina, along with some flurine gas.
The barium aluminate may be eliminated by washing with water or acid, and the fluorine gas is volatilized.
The pcalc intensity of the phosphor produced according to this example was more ~han 2 times as high as was observ~d in the case of the cerium activated phosphor which had not been sintered in the presence of the fluoride. Moreover, the decay time which is the time that the emissiYe intensity decays to û. 1 of the peak intensity, was measured to be 110 nanoseconds in the case of the phosphor produ^ed according to the example, whereas a phospllor which is prepared without the fluoride compound evidenced a decay time of 120 nanoseconds. Thus, in accordance with the present invention, the peak intensity is increased and th2 decay time is decreased so that the ratio of pealc intensity to decay time is substantially increased.
?54 The relationship bctween the relative peal~ intensity and the decay time to the concentration of barium fluoride is shown in FIGS.
1 and 2 of the drawings. In FIGS. 1 and 2, the ~bscissae refer to the molar concentration of barium fluoride. As shown in these two Figures, when the concentration of the barium compound is between 1 and 50 mol percent, preferably between 2. 5 and 40 mol percent, the relative peak intensity and the dccay time are improved.
The ratio of the relative peak intensity to the deca~r time is plotted as a function of the concentration of barium fluoride in FIG
3. It is apparent from this Figure that the phosphor has optimum properties by using a concentration of barium fluoride or other fluoride between 1 and 50 mol percent. Since the phosphor produced according to the present invention has characteristics of higher peak intensity oE emission and shorter decay time than those of the conventional phospllor, it can conveniently be used as a phosphor in a beam indexing color cathode ray tube or in a flying spot scanner tube.
Although the invention has been described in connection with preferred embodiments, it is not to be so limited as changes and modifications can be made which are within the full intended scope as de~ined by the appended claims.
Claims (7)
1. A method of manufacturing a luminescent material excitable by an electron beam and consisting essentially of cerium activated yttrium aluminum gallium oxide crystals of the form Y3 Alx Gay 012:CE whereas X+Y-5, X=1 to 4, Y=4 to 1 com-prising the steps of providing a mixture of yttrium oxide, aluminum oxide, gallium oxide, cerium oxide and an inorganic fluoride which melts to liberate fluorine at the sintering tem-perature of said mixture, and heating said mixture under sealed conditions to a sintering temperature and sintering the mixture to produce a material having a higher ratio of peak intensity to decay time than results from the sintering of said mixture in the absence of said fluoride.
2. The method of claim 1 in which said fluoride is barium fluoride.
3. The method of claim 1 in which said fluoride is ammonium difluoride.
4. The method of claim 1 in which said fluoride is present in an amount of from 1 to 50 mols for every 100 mols of the remainder of said mixture.
5. The method of claim 1 in which said fluoride is present in an amount of 2.5 to 40 mols for every 100 mols of the remainder of said mixture.
6. The method of claim 1 in which the mixture is sintered at a temperature of from 1400 to 1700°C for from 1 to 6 hours.
7. The method of claim 1 in which the mixture is sintered at 1500 to 1600°C for from 2 to 4 hours.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP66078/77 | 1977-06-03 | ||
| JP6607877A JPS541287A (en) | 1977-06-03 | 1977-06-03 | Fluorescent substance |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1110054A true CA1110054A (en) | 1981-10-06 |
Family
ID=13305445
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA304,420A Expired CA1110054A (en) | 1977-06-03 | 1978-05-30 | Cerium activated phosphor and method of making same |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS541287A (en) |
| CA (1) | CA1110054A (en) |
| DE (1) | DE2824255A1 (en) |
| FR (1) | FR2393047A1 (en) |
| GB (1) | GB1597306A (en) |
| NL (1) | NL7805931A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5857491A (en) * | 1981-09-30 | 1983-04-05 | Sony Corp | Preparation of green fluorescent material |
| CN101128563B (en) * | 2005-02-28 | 2012-05-23 | 三菱化学株式会社 | Phosphor, its manufacturing method and application |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3657140A (en) * | 1970-05-26 | 1972-04-18 | Edward F Gibbons | Cerium activated solid solution yttrium gallium oxide phosphor |
| JPS5246190B2 (en) * | 1973-01-31 | 1977-11-22 | ||
| JPS5918433B2 (en) * | 1975-06-02 | 1984-04-27 | 松下電器産業株式会社 | fluorescent material |
-
1977
- 1977-06-03 JP JP6607877A patent/JPS541287A/en active Granted
-
1978
- 1978-05-23 GB GB21512/78A patent/GB1597306A/en not_active Expired
- 1978-05-29 FR FR7815963A patent/FR2393047A1/en active Granted
- 1978-05-30 CA CA304,420A patent/CA1110054A/en not_active Expired
- 1978-05-31 NL NL7805931A patent/NL7805931A/en not_active Application Discontinuation
- 1978-06-02 DE DE19782824255 patent/DE2824255A1/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| NL7805931A (en) | 1978-12-05 |
| JPS541287A (en) | 1979-01-08 |
| FR2393047B1 (en) | 1980-10-31 |
| GB1597306A (en) | 1981-09-03 |
| DE2824255C2 (en) | 1991-01-03 |
| FR2393047A1 (en) | 1978-12-29 |
| DE2824255A1 (en) | 1978-12-14 |
| JPS6136038B2 (en) | 1986-08-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |