Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS1954691 A
Publication typeGrant
Publication dateApr 10, 1934
Filing dateSep 18, 1931
Priority dateSep 27, 1930
Publication numberUS 1954691 A, US 1954691A, US-A-1954691, US1954691 A, US1954691A
InventorsDe Boer Jan Hendrik, Johannes Dippel Cornelis
Original AssigneePhilips Nv
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Process of making alpha layer containing alpha fluorescent material
US 1954691 A
Abstract  available in
Images(1)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

April 10, 1934. J. H. DE BOER ET AL PROCESS OF HAKING A LAYER CONTAINING A FLUORESCENT MATERIAL Filed Sept. 18, 1951 Patented Apr. 10, 1934 UNITED STATES rnocass' OF MAKING A LAYER CONTAIN- me A FLUORESCENT MATERIAL Jan Hendrik de Boer and Cornelis J ohannw Dippel, Eindhoven, Netherlands, assisnors to N. V. Philips Gloeilampenfabrieken, Eindhoven, Netherlands Application September 18, 1931, Serial No. 563,650 In the Netherlands September 2'], 1930 4 Claims.

This invention relates to a method of making a layer containing a fluorescent material. Such fluorescing layers are used for various purposes, for example, as X-ray intensifying screens.

When making such a layer according to the invention the fluorescent material is volatilized and precipitated in a vacuum.

It has been found that a fluorescing layer formed in this manner has a very uniform structure. In fact, all of the molecules precipitated appear to have the same orientation. By this uniform structure the fluorescence of the layer is increased.

In some cases it is desired to obtain fluorescing layers having such a thickness that they are transparent to light. For this purpose the method according to the invention is particularly suitable. In fact, a fluorescing layer formed by means of this method may be given a greater thickness than a fluorescing layer which does not have such a uniform structure without the transparency being unfavourably affected thereby.

An additional advantage of the method according to the invention consists in that the nature 0 of the grain of the fluorescent material precipitated may be varied by modifying the rate of volatilization. As a rule the-size of the grains will be small at a quick volatilization which is of great importance, for example, in the -manufac-' ture of X-ray intensifying screens. It is found that the image taken on such a screen will be sharper as the size of the grains of the fluorescent material is reduced.

. For a better understanding of the present invention, reference should be had to the accompanying drawing, wherein Figure 1 is a sectional view of apparatus that may be used to carry out the improved process according to the invention; and

Fig. 2 is a plan view of the base or sheet on which the fluorescent layer is to be formed showing the filament from which the sensitive material is volatilized.

The apparatus comprises a glass vessel or bulb 1 closed by a stopper 2. Leading-in wires 3 and a suitable source, such as a transformer 9, so as to be heated to incandescence-after the bulb 1 has been evacuated through the connection 10. The wire 8 is coated with fluorescent material, such as zinc sulphide .or calcium tungstate, which is volatilized by the heating of said wire and precipitates in the form of a layer on the upper surface of the sheet 'I. A fluorescent layer having a fine, uniform structure and improved sensitivity is thereby produced. The sheet '1 may, if desired, be first coated with a layer, consisting of a material by which the fluorescent material is perfectly adsorbed, before it is subjected to the described coating process.

The fluorescent layer on the sheet 7 may comprise a mixture of fluorescent substances which i may be volatilized simultaneously. This layer may also contain other substances in addition to the fluorescent material. These substances may be incorporated into the layer, for example, by volatilizing them simultaneously with the fluorescent material in the bulb 1.

The fluorescent layer formed in this manner is found to have novel and unexpected properties.

In comparison with the layers formed by the processes hitherto employed, the layer has a more uniform structure, is much more transparent and possesses enhanced sensitivity. The fluorescence obtained is greatly increased while the light absorption is decreased. I I What we claim is: i 1. A method of making an X-ray intensifying screen, in which a suitable base together with a quantity of fluorescent material is introduced into 4. A method of making a ray-sensitive screen comprising volatilizing and precipitating calcium ungstate on a sheet or base in a vacuum.

' JAN HENDRIK as BOER.

- CORNELIS JOHANN'ES DIPPEL.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2451292 *Dec 20, 1943Oct 12, 1948Rca CorpDark trace screen
US2462517 *Sep 29, 1942Feb 22, 1949Rca CorpMethod of manufacture of luminescent materials
US2497140 *Mar 28, 1946Feb 14, 1950Sylvania Electric ProdMethod of manufacture of luminescent materials
US2511572 *Sep 7, 1946Jun 13, 1950Sylvania Electric ProdLuminescent screen and method of manufacture
US2538562 *May 30, 1945Jan 16, 1951Westinghouse Electric CorpElectrostatic coating method and apparatus
US2600579 *Jun 5, 1946Jun 17, 1952Rca CorpMethod of making phosphor screens
US2616057 *May 20, 1950Oct 28, 1952Westinghouse Electric CorpBlack screen television cathode-ray tube
US2616817 *Feb 14, 1947Nov 4, 1952Hartford Nat Bank & Trust CoLuminescent screen
US2673816 *Dec 21, 1950Mar 30, 1954Leitz Ernst GmbhProcess for making monocrystal actinic screen
US2690979 *Feb 7, 1951Oct 5, 1954Rca CorpMethod of powder-coating television screens
US2998323 *Apr 5, 1957Aug 29, 1961Davohn CorpMethod for making luminescent screens
US3961182 *Aug 18, 1972Jun 1, 1976Varian AssociatesPick up screens for X-ray image intensifier tubes employing evaporated activated scintillator layer
US5600200 *Jun 7, 1995Feb 4, 1997Microelectronics And Computer Technology CorporationWire-mesh cathode
US5601966 *Jun 7, 1995Feb 11, 1997Microelectronics And Computer Technology CorporationMethods for fabricating flat panel display systems and components
US5612712 *Jun 7, 1995Mar 18, 1997Microelectronics And Computer Technology CorporationDiode structure flat panel display
US5614353 *Jun 7, 1995Mar 25, 1997Si Diamond Technology, Inc.Methods for fabricating flat panel display systems and components
US5652083 *Jun 7, 1995Jul 29, 1997Microelectronics And Computer Technology CorporationMethods for fabricating flat panel display systems and components
US5675216 *Jun 7, 1995Oct 7, 1997Microelectronics And Computer Technololgy Corp.Amorphic diamond film flat field emission cathode
US5679043 *Jun 1, 1995Oct 21, 1997Microelectronics And Computer Technology CorporationMethod of making a field emitter
US5686791 *Jun 7, 1995Nov 11, 1997Microelectronics And Computer Technology Corp.Amorphic diamond film flat field emission cathode
US5697824 *Jun 7, 1995Dec 16, 1997Microelectronics And Computer Technology Corp.Method for producing thin uniform powder phosphor for display screens
US5703435 *May 23, 1996Dec 30, 1997Microelectronics & Computer Technology Corp.Diamond film flat field emission cathode
US5763997 *Jun 1, 1995Jun 9, 1998Si Diamond Technology, Inc.Field emission display device
US5861707 *Jun 7, 1995Jan 19, 1999Si Diamond Technology, Inc.Field emitter with wide band gap emission areas and method of using
US6127773 *Jun 4, 1997Oct 3, 2000Si Diamond Technology, Inc.Amorphic diamond film flat field emission cathode
US6629869Jun 7, 1995Oct 7, 2003Si Diamond Technology, Inc.Method of making flat panel displays having diamond thin film cathode
DE977171C *Jan 29, 1952May 6, 1965Gen ElectricVerfahren zur Herstellung eines praktisch kornlosen Leuchtschirmes
Classifications
U.S. Classification427/65, 250/488.1, 976/DIG.439, 427/70, 313/483, 252/301.5, 313/107.5
International ClassificationG21K4/00
Cooperative ClassificationG21K4/00
European ClassificationG21K4/00