Coated phosphors

Claim 2

A PHOSPHOR COMPOSITE IN PARTICULATE FORM, EACH PARTICLE COMPRISING A PHOSPHOR CORE OF SUBSTANTIALLY UNIFORM COMPOSITION THROUGHOUT, SUBSTANTIALLY COMPLETELY SURROUNDED BY A COATING WHICH MODIFIES THE LUMINESCENT QUALITY OF THE COMPOSITE, SAID COATING COMPRISING A FILTER COATING (A) BEING OF A THICKNESS SUCH AS TO PERMIT THE TRANSMISSION THERETHROUGH OF AT LEAST A PORTION OF THE LIGHT EMITTED BY THE PHOSPHOR CORE PARTICLE, (B) BEING OF SUBSTANTIALLY UNIFORM COMPOSITION THROUGHOUT ITS THICKNESS, AND (C) BEING COALESCED INTO A SUBSTANTIALLY CONTINUOUS FILM ENVELOPING THE UNDERLYING PHOSPHOR CORE PARTICLE AND LEAVING SUBSTANTIALLY NO PORTION THEREOF UNCOVERED, THERE BEING NO BARRIER LAYER BETWEEN SAID PHOSPHOR CORE AND SAID COATING.

Claim 3

A phosphor composite according to claim 1, wherein each phosphor core particle is completely surrounded by a filter coating, said coating being sintered into a substantially continuous film forming a filter layer about the phosphor particles and being substantially free of discrete granules of the coating material, there being essentially no interdiffusion of said coating with said phosphor.

Claim 4

A phosphor composite according to claim 2 wherein one or more alkali metals is present at the juncture between the phosphor and the coating.

Claim 5

A phosphor composite according to claim 3 wherein the alkali metal comprises below about 0.5% by weight of the phosphors, said alkali metal selected from the group consisting of sodium, potassium, lithium and mixtures thereof.

Claim 6

A phosphor composite according to claim 2 wherein a substantially transparent protective coating of a resin surrounds said filter layer.

Claim 7

A phosphor composite according to claim 5 wherein the resin is polyvinyl alcohol.

Claim 8

A phosphor composite according to claim 2 wherein the phosphor particles are red emitting phosphors and the filter layer is cadmium sulfoselenide.

Claim 9

A phosphor composIte according to claim 7 wherein the phosphor is a red rare earth phosphor selected from the group consisting of red rare earth oxide phosphors, red rare earth oxysulfide phosphors and red rare earth vanadate phosphors.

Claim 10

A phosphor composite according to claim 8 wherein the red phosphor is a europium activated rare earth phosphor selected from the group consisting of gadolinium oxide, yttrium oxide, gadolinium oxysulfide, lanthanum oxysulfide and yttrium oxysulfide.

Claim 11

A phosphor composite according to claim 2 wherein the phosphor particles are yellow emitting phosphors and the filter layer is cadmium sulfide.

Claim 12

A rare earth phosphor composition comprising particles of a europium-activated red rare earth phosphor selected from the group consisting of gadolinium oxide, yttrium oxide, gadolinium oxysulfide, lanthanum oxysulfide and yttrium oxysulfide, each particle being substantially completely surrounded by a filter coating of cadmium sulfoselenide, said coating being sintered into a substantially continuous film forming a red transmitting filter layer and being substantially free of discrete granules of the coating material, and each particle further having a substantially transparent protective coating of a resin surrounding said filter layer, there being essentially no interdiffusion of said coating with said phosphor, there being no barrier layer between said particles and said filter layer.

Claim 13

A rare earth phosphor composition comprising particles of a europium-activated red rare earth phosphor selected from the group consisting of gadolinium oxide, yttrium oxide, gadolinium oxysulfide, lanthanum oxysulfide and yttrium oxysulfide, each particle being substantially completely surrounded by a filter coating of cadmium sulfoselenide, said coating being sintered into a substantially continuous film forming a red transmitting filter layer and being substantially free of discrete granules of the coating material, and each particle further having a substantially transparent protective coating of a resin surrounding said filter layer, there being essentially no interdiffusion of said coating with said phosphor, there being no barrier layer between said particles and said filter layer.

Claim 14

The rare earth phosphor composition according to claim 11 wherein the resin is polyvinyl alcohol.

Claim 15

A rare earth phosphor composition comprising europium activated gadolinium oxide particles, each particle being substantially completely surrounded by a filter coating of cadmium sulfoselenide, said coating being sintered into a substantially continuous film forming a red transmitting filter layer and being substantially free of discrete granules of the coating material, and a protective coating of a polyvinyl alcohol resin surrounding said filter layer, there being essentially no interdiffusion of said coating with said phosphor, there being no barrier layer between said particles and said filter layer.

Claim 16

A rare earth phosphor composition comprising europium activated gadolinium oxide particles, each particle being substantially completely surrounded by a filter coating of cadmium sulfoselenide, said coating being sintered into a substantially continuous film forming a red transmitting filter layer and being substantially free of discrete granules of the coating material, and a protective coating of a polyvinyl alcohol resin surrounding said filter layer, there being essentially no interdiffusion of said coating with said phosphor, there being no barrier layer between said particles and said filter layer.

Claim 17

A rare earth phosphor composition comprising europium activated yttrium oxide particles, each particle being substantially completely surrounded by a filter coating of cadmium sulfoselenide, said coating being sintered into a substantially continuous film forming a red transmitting filter layer and being substantially free to discrete granules of the coating material, and a protective coating of a polyvinyl alcolhol resin surrounding said filter layer, there being essentially no interdiffusion of said coating with said phosphor.

Claim 18

A rare earth phosphor composition comprising europium activated yttrium oxide particles, each particle being substantially completely surrounded by a filter coating of cadmium sulfoselenide, said coating being sintered into a substantially continuous film forming a red transmitting filter layer and being substantially free to discrete granules of the coating material, and a protective coating of a polyvinyl alcolhol resin surrounding said filter layer, there being essentially no interdiffusion of said coating with said phosphor.

Claim 19

A rare earth phosphor composition comprising europium activated lanthanum oxysulfide particles, each particle being substantially completely surrounded by a filter coating of cadmium sulfoselenide, said coating being sintered into a substantially continuous film forming a red transmitting filter layer and being substantially free of discrete granules of the coating material, and a protective coating of a polyvinyl alcohol resin surrounding said filter layer, there being essentially no interdiffusion of said coating with said phosphor.

Claim 20

A rare earth phosphor composition comprising europium activated lanthanum oxysulfide particles, each particle being substantially completely surrounded by a filter coating of cadmium sulfoselenide, said coating being sintered into a substantially continuous film forming a red transmitting filter layer and being substantially free of discrete granules of the coating material, and a protective coating of a polyvinyl alcohol resin surrounding said filter layer, there being essentially no interdiffusion of said coating with said phosphor.

Claim 21

A phosphor composite according to claim 1, wherein each phosphor core particle is substantially completely surrounded by a phosphor coating which emits light of different color than the phosphor core.

Claim 22

A phosphor composite according to claim 16 wherein a substantially transparent protective coating of a resin surrounds said phosphor coating.

Claim 23

A phosphor composite according to claim 16 disposed on the image screen of a cathode ray tube, whereby said screen luminesces with light predominantly of the color emitted by the phosphor core wherein the energy of the cathode ray beam is relatively high and luminesces with light predominantly of the coloremitted by the phosphor coating when the energy of the cathode ray beam is relatively low and luminesces with light of a mixture of said colors when the enregy of the cathode ray beam is intermediate said relatively high and relatively low energies.

Claim 24

A cathode ray tube comprising a phosphor-coated image screen and means for projecting a beam of cathode ray electrons against said phosphor coating, characterized in that said phosphor coating comprises a phosphor composite according to claim 16.

Claim 25

A red phosphor composition comprising particles of a red emitting phosphor, each phosphor particle being substantially completely surrounded by a coating of cadmium sulfoselenide, said coating being sintered into a substantially continuous film forming a red transmitting filter layer about the phosphor particle and being substantially free of discrete granules of the coating material, there being essentially no interdiffusion of said coating with said phosphor, there being no barrier layer between said particles and said coating.

Claim 26

A red phosphor composition comprising particles of a red emitting phosphor, each phosphor particle being substantially completely surrounded by a coating of cadmium sulfoselenide, said coating being sintered into a substantially continuous film forming a red transmitting filter layer about the phosphor particle and being substantially free of discrete granules of the coating material, there being essentially no interdiffusion of said coating with said phosphor, there being no barrier layer between said particles and said coating.

Claim 27

A phosphor composition according to claim 20 characterized in that one or more alkali metals is present at the juncture between the phosphor and the coating.

Claim 28

A phosphor composition according to claim 21 in which the alkali metal comprises below about 0.5% by weight of the phosphors, said alkali metal selected from the group consisting of sodium, potassium, lithium and mixtures thereof.

Claim 29

A phosphor composition accoring to claim 20 characterized in that a substantially transparent protective coating of a resin surrounds said filter layer.

Claim 30

A phosphor composition according to claim 20 in which the red phosphor is a red earth phosphor selected from the group consisting of red rare earth oxide phosphors and red rare earth oxysulfide phosphors.

Claim 31

A phosphor composition according to claim 20 in which the red phosphor is a europium activated rare earth phosphor selected from the group consisting of gadolinium oxide, yttrium oxide, gadolinium oxysulfide, lanthanum oxysulfide and yttrium oxysulfide.