Patents by Inventor George W. Berkstresser
George W. Berkstresser has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5164041Abstract: The invention is a technique for the growth of single crystals of rare earth doped rare-earth orthosilicate crystals which may be used as the laser medium in solid-state non-semiconductor lasers. This type of laser has applications in electronics, communications, aerospace systems, and manufacturing technology where high optical output lasers are utilized. Of particular interest is the Y.sub.2-x Nd.sub.x SiO.sub.5 crystal, with x being up to 0.3, which may be efficiently pumped by a semiconductor laser, solid state non-semiconductor laser, a flashlamp or some other source of light radiation, and has been found to be operable at very high optical output. The rare-earth orthosilicate crystals are grown in accordance with this invention by a Czochralski technique from a molten mixture of constituent oxides in an inert atmosphere containing oxygen.Type: GrantFiled: January 4, 1991Date of Patent: November 17, 1992Assignee: AT&T Bell LaboratoriesInventors: George W. Berkstresser, Charles D. Brandle, Jr.
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Patent number: 4894583Abstract: Certain yttrium orthosillicate phosphors doped with various rare-earths are particularly suitable for use in various display devices including cathode ray tubes. Included are single crystal phosphors which exhibit high brightness and long life under high energy excitation and conventional powder phosphors with great sensitivity.Type: GrantFiled: September 2, 1988Date of Patent: January 16, 1990Assignee: American Telephone and Telegraph Company, AT&T Bell LaboratoriesInventors: George W. Berkstresser, Charles D. Brandle, Jr., Joseph Shmulovich, Alejandro J. Valentino
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Patent number: 4835437Abstract: Light output of single crystal phosphors used on cathode ray tubes can be vastly improved by use of a microfaceted surface structure conveniently produced by use of a single crystal epitaxial layer with lattice constant slightly larger than the single crystal substrate. Such epitaxial layers are conveniently grown using substituents that increase the lattice constant compared to the single crystal substrate.Type: GrantFiled: May 16, 1988Date of Patent: May 30, 1989Assignee: American Telephone and Telegraph Company, AT&T Bell LaboratoriesInventors: George W. Berkstresser, Charles D. Brandle, Jr.
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Patent number: 4807241Abstract: The luminescent screen of a cathode ray tube includes an array of monocrystalline or amorphous phosphor rod-like elements which are covered with a reflective coating except for one end of each element which serves as an output face. The phenomenon of the light trapping is advantageously exploited to achieve enhanced brightness. The screen is illuminated with an electron beam which has an essentially oblong cross section and which is oriented along the elongated dimension of the elements. In one embodiment the elements comprise epitaxial Lu.sub.3 Al.sub.3 Ga.sub.2 O.sub.12 :Ce on the top of a YAG substrate, and a light absorbing layer of Lu.sub.3 Al.sub.3.5 Fe.sub.1.5 O.sub.12 is formed on the bottom of the substrate. A printer utilizing such a CRT is described. Also described is a configuration in which each of the rod-like elements functions as a laser.Type: GrantFiled: July 10, 1987Date of Patent: February 21, 1989Assignee: American Telephone and Telegraph Company AT&T Bell LaboratoriesInventors: George W. Berkstresser, Joseph Shmulovich
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Patent number: 4757232Abstract: A novel epitaxial phosphor having high luminosity at about 540 nm has the composition (Y.sub.3-x-y Tb.sub.x RE.sub.y)(Al.sub.5-w Ga.sub.w)O.sub.12, with RE being one (or more) 4f-type rare earth(s) other than Tb, 0.09<x<0.7, and 1.5<w<2.5. In preferred embodiments, RE is Lu, Yb, or Tm, 0.1<x<0.3, and 1.8<w<2.2. In further preferred embodiments, the phosphor composition is adjusted to yield a material having a lattice constant within 0.002 nm of the lattice constant of the substrate, typically Y.sub.3 Al.sub.5 O.sub.12. The phosphor is typically grown by liquid phase epitaxy and has application in a variety of apparatus, including avionic displays and flight simulators.Type: GrantFiled: January 16, 1985Date of Patent: July 12, 1988Assignee: American Telephone and Telegraph Company, AT&T Bell LaboratoriesInventors: George W. Berkstresser, Tai-Chan D. Huo, Joseph Shmulovich
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Patent number: 4755715Abstract: A phosphor for use in CRTs comprises (Y.sub.3-p-m-n R.sub.p Pr.sub.m Tb.sub.n)(Al.sub.5-q Z.sub.q)O.sub.12, where R is a lanthanide element and Z is a Group III element. One embodiment described is a single crystal of (Y.sub.3-m-n Pr.sub.m Tb.sub.n)Al.sub.5 O.sub.12 in which the trivalent Pr and Tb activators exhibit co-emission and the phosphor emits white light.Type: GrantFiled: February 28, 1986Date of Patent: July 5, 1988Assignee: American Telephone & Telegraph Company, AT&T Bell LaboratoriesInventors: George W. Berkstresser, Joseph Shmulovich
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Patent number: 4695762Abstract: The luminescent screen of a cathode ray tube includes an array of monocrystalline or amorphous phosphor rod-like elements which are covered with a reflective coating except for one end of each element which serves as an output face. The phenomenon of the light trapping is advantageously exploited to achieve enhanced brightness. The screen is illuminated with an electron beam which has an essentially oblong cross section and which is oriented along the elongated dimension of the elements. In one embodiment the elements comprise epitaxial Lu.sub.3 Al.sub.3 Ga.sub.2 O.sub.12 :Ce on the top of a YAG substrate, and a light absorbing layer of Lu.sub.3 Al.sub.3.5 Fe.sub.1.5 O.sub.12 is formed on the bottom of the substrate. A printer utilizing such a CRT is described. Also described is a configuration in which each of the rod-like elements functions as a laser.Type: GrantFiled: June 28, 1985Date of Patent: September 22, 1987Assignee: American Telephone and Telegraph Company, AT&T Bell LaboratoriesInventors: George W. Berkstresser, Joseph Shmulovich
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Patent number: 4550256Abstract: The disclosed display apparatus comprises a novel high intensity broadband-emitting phosphor. The phosphor is single crystal material in which Tb acts as sensitizer of Ce, the activator. The composition of the phosphor is (Y.sub.3-x-y-z Ce.sub.x Tb.sub.y RE.sub.z) Al.sub.5-w X.sub.w O.sub.12, where RE is one or more 4f-type rare earths other than Y, Ce, and Tb, X is Sc, Ga, or In, and 0<x.ltoreq.0.06, 0<y.ltoreq.0.5, 0.ltoreq.z.ltoreq.2, 0.ltoreq.w.ltoreq.3. In preferred embodiments z and w are either zero, or RE is Lu and X is Ga. The phosphor is typically grown epitaxially by LPE on a Y.sub.3 Al.sub.5 O.sub.12 substrate, and has application in a variety of apparatus, including aircraft cockpit head-up displays and flight simulators.Type: GrantFiled: October 17, 1983Date of Patent: October 29, 1985Assignee: AT&T Bell LaboratoriesInventors: George W. Berkstresser, Tai-Chan D. Huo, Joseph Shmulovich
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Patent number: 4400445Abstract: The manufacture of magnetic bubble devices typically involves a step of epitaxially depositing a layer of a garnet material on a substrate having suitable lattice parameters, e.g., layers of certain rare earth-iron garnets are conveniently deposited on a gallium-gadolinium garnet substrate. Deposition by liquid epitaxy has been preferred and, in particular, deposition from a melt comprising garnet materials in a PbO--B.sub.2 O.sub.3 flux.According to the invention, garnet layers are epitaxially grown from a melt comprising a PbO--V.sub.2 O.sub.5 flux. Growth from such melt has desirably slow kinetics, resulting in slow deposition as is beneficial especially for the growth of layers on an assembly of substrates. Additional benefits are ease of removal of liquid droplets remaining on a grown film upon removal from the melt, both by spinning and by rinsing.Type: GrantFiled: November 18, 1981Date of Patent: August 23, 1983Assignee: Bell Telephone Laboratories, IncorporatedInventors: George W. Berkstresser, Stuart L. Blank