Claims
- 1. A CRT having a surface with reduced gloss comprising a CRT having a coating on the surface thereof, said coating being provided by applying fine droplets of a solution of a silane and a saturated hydrocarbon selected from the group consisting of saturated straight chain paraffinic hydrocarbons having the formula C.sub.n H.sub.2n+2 and saturated cyclic napthenic hydrocarbons having the formula C.sub.n H.sub.2n in a solvent system comprising an alcohol and water onto the surface of said CRT and curing the silane and saturated hydrocarbon for a period of time sufficient to convert said silane to a siloxane being in the form of a random distribution of substantially uniform undulations.
- 2. A CRT in accordance with claim 1 wherein n is an integer of from 8 to 16.
- 3. A CRT in accordance with claim 1 wherein said saturated hydrocarbon is selected from kerosene, jet fuel and mixtures thereof.
- 4. A CRT in accordance with claim 1 wherein said silane is present on the surface of said cathode ray tube at a level of from about 0.3 to about 1.2 milligrams per square centimeter of said surface area of said cathode ray tube.
- 5. A CRT in accordance with claim 1 wherein said solution is applied by spraying a fine mist of said solution onto said surface.
- 6. A CRT in accordance with claim 1 wherein said silane is present in said solution at a level of from about 0.5 percent to about 50 percent, based on the weight of said solution.
- 7. A CRT in accordance with claim 1 wherein said alcohol is propanol.
- 8. A CRT in accordance with claim 1 wherein said solution droplets have a diameter of from about 0.3 to about 0.5 microns.
- 9. A CRT in accordance with claim 1 wherein said silane is an alkoxy or aryloxy silane which is present in said solution at a level of from about 0.5% to about 50%, said saturated hydrocarbon is present in said solution at a level of from about 0.1% to about 10%, said alcohol is present in said solution at a level of from 0% to about 95% and said water is present in said solution at a level of from 5% to 100%.
- 10. A CRT in accordance with claim 1 wherein said surface of said cathode ray tube is preheated prior to application of said solution.
- 11. A CRT in accordance with claim 1 wherein said cathode ray tube is preheated to a temperature in the range of from about 70.degree. C. to about 120.degree. C. prior to applying said solution.
- 12. A CRT in accordance with claim 1 wherein said silane is present on the surface of said cathode ray tube at a level of from about 0.3 to about 1.2 milligrams per square centimeter of said surface area of said cathode ray tube.
- 13. A CRT in accordance with claim 1 wherein said solution is applied to said surface of said cathode ray tube by multiple spray passes.
- 14. A CRT in accordance with claim 13 wherein from 3 to 12 spray passes are used to apply said solution.
- 15. A CRT in accordance with claim 1 wherein said alcohol is a C.sub.1 -C.sub.4 aliphatic alcohol.
- 16. A CRT in accordance with claim 15 wherein said alcohol is ethanol.
- 17. A CRT in accordance with claim 1 wherein said saturated hydrocarbon is present in said solution at a level of from about 0.1% to about 10%.
- 18. A CRT in accordance with claim 17 wherein said saturated hydrocarbon is present in said solution at a level of from about 0.2% to about 1%.
- 19. A CRT in accordance with claim 1 wherein said silane is selected from the group consisting of tetraalkoxy silanes, tetraaryloxy silanes and halogenated silanes.
- 20. A CRT in accordance with claim 19 wherein said silane is selected from the group consisting of tetrachlorosilane, trichlorosilane, tetramethoxysilane and tetraethoxysilane.
- 21. A CRT in accordance with claim 20 wherein said silane is a halogenated silane which is present in said solution at a level of from about 0.5 to about 50%, said saturated hydrocarbon is present in said solution at a level of from about 0.1% to about 10%, said alcohol is present in said solution at a level of from about 55% to about 95% and water is present in said solution at a level of from about 5% to about 45%.
- 22. In a cathode ray tube, a front panel having on a first surface an antiglare, antistatic coating resulting from application of a solution of a silane and a saturated hydrocarbon selected from the group consisting of saturated straight chain paraffinic hydrocarbons having the formula C.sub.n H.sub.2n+2 and saturated cyclic napthenic hydrocarbons having the formula C.sub.n H.sub.2n in a solvent system comprising alcohol and water, said coating having a distinctive topography of a random distribution of substantially uniform undulations which are of uniform texture and which is substantially devoid of craters or other circular formations suggestive of particle spattering.
- 23. A CRT in accordance with claim 22 wherein the gloss is less than about 45 percent.
- 24. A CRT in accordance with claim 22 wherein a 25 Kv surface charge is reduced to less than 1 Kv in less than about 50 seconds.
- 25. A CRT having a surface with reduced gloss comprising a CRT having a coating on the surface thereof, said coating being provided by applying fine droplets of a solution consisting essentially of a silane and a saturated hydrocarbon in a solvent system comprising an alcohol and water onto the surface of said CRT and curing the silane and saturated hydrocarbon for a period of time sufficient to convert said silane to a siloxane coating on the surface of said cathode ray tube.
- 26. A CRT in accordance with claim 25 wherein said saturated hydrocarbon is selected from kerosene, jet fuel and mixtures thereof.
- 27. A CRT in accordance with claim 25 wherein said silane is present on the surface of said cathode ray tube at a level of from about 0.3 to about 1.2 milligrams per square centimeter of said surface area of said cathode ray tube.
- 28. A CRT in accordance with claim 25 wherein said solution is applied by spraying a fine mist of said solution onto said surface.
- 29. A CRT in accordance with claim 25 wherein said silane is present in said solution at a level of from about 0.5 percent to about 50 percent, based on the weight of said solution.
- 30. A CRT in accordance with claim 25 wherein said alcohol is propanol.
- 31. A CRT in accordance with claim 25 wherein said solution droplets have a diameter of from about 0.3 to about 0.5 microns.
- 32. A CRT in accordance with claim 25 wherein said silane is an alkoxy or aryloxy silane which is present in said solution at a level of from about 0.5% to about 50%, said saturated hydrocarbon is present in said solution at a level of from about 0.1% to about 10%, said alcohol is present in said solution at a level of from 0% to about 95% and said water is present in said solution at a level of from 5% to 100%.
- 33. A CRT in accordance with claim 25 wherein said saturated hydrocarbon is present in said solution at a level of from about 0.1% to about 10%.
- 34. A CRT in accordance with claim 33 wherein said saturated hydrocarbon is present in said solution at a level of from about 0.2% to about 1%.
- 35. A CRT in accordance with claim 25 wherein said saturated hydrocarbon is selected from the group consisting of saturated straight chain paraffinic hydrocarbons having the formula C.sub.n H.sub.2n+2 and saturated cyclic napthenic hydrocarbons having the formula C.sub.n H.sub.2n.
- 36. A CRT in accordance with claim 35 wherein n is an integer of from 8 to 16.
- 37. A CRT in accordance with claim 25 wherein said surface of said cathode ray tube is preheated prior to application of said solution.
- 38. A CRT in accordance with claim 37 wherein said cathode ray tube is preheated to a temperature in the range of from about 70.degree. C. to about 120.degree. C. prior to applying said solution.
- 39. A CRT in accordance with claim 37 wherein said silane is present on the surface of said cathode ray tube at a level of from about 0.3 to about 1.2 milligrams per square centimeter of said surface area of said cathode ray tube.
- 40. A CRT in accordance with claim 25 wherein said solution is applied to said surface of said cathode ray tube by multiple spray passes.
- 41. A CRT in accordance with claim 40 wherein from 3 to 12 spray passes are used to apply said solution.
- 42. A CRT in accordance with claim 25 wherein said alcohol is a C.sub.1 -C.sub.4 aliphatic alcohol.
- 43. A CRT in accordance with claim 42 wherein said alcohol is ethanol.
- 44. A CRT in accordance with claim 25 wherein said silane is selected from the group consisting of tetraalkoxy silanes, tetraaryloxy silanes and halogenated silanes.
- 45. A CRT in accordance with claim 44 wherein said silane is selected from the group consisting of tetrachlorosilane, trichlorosilane, tetramethoxysilane and tetraethoxysilane.
- 46. A CRT in accordance with claim 45 wherein said silane is a halogenated silane which is present in said solution at a level of from about 0.5 to about 50%, said saturated hydrocarbon is present in said solution at a level of from about 0.1% to about 10%, said alcohol is present in said solution at a level of from about 55% to about 95% and water is present in said solution at a level of from about 5% to about 45%.
- 47. In a cathode ray tube, a front panel having on first surface an antiglare, antistatic coating resulting from application of a solution consisting essentially of a silane and a saturated hydrocarbon in a solvent system comprising alcohol and water, said coating having a distinctive topography of a random distribution of substantially uniform undulations which are of uniform texture and which is substantially devoid of craters or other circular formations suggestive of particle spattering.
- 48. A CRT in accordance with claim 47 wherein the gloss is less than about 45 percent.
- 49. A CRT in accordance with claim 47 wherein a 25 Kv surface charge is reduced to less than 1 Kv in less than about 50 seconds.
RELATED APPLICATIONS
The present application is a continuation-in-part of United States patent application Ser. No. 558,993, filed on Jul. 27, 1990 and now abandoned.
The present invention relates generally to a cathode ray tube (CRT) having a coating on the face panel thereof which provides antiglare and antistatic properties. More particularly, the present invention relates to a method for providing an antiglare and antistatic coating on the face panel of CRT's.
Cathode ray tubes are increasingly being used as visual display terminals (VDTs) which are scanned at close range by the human eye. It is desirable to minimize the glare that is reflected from the glass surface of the CRT so as to enable the user to more easily read the graphics and other display characters that are shown on the screen.
Various methods are known for reducing the glare on CRT face panels. In one known method, a double layer of ultra fine metal oxide particles are applied onto the surface of the face panel. Tin oxide particles, having a diameter of about 50 nm, are suspended in a solution of ethyl silicate and ethanol. The suspension of tin oxide particles is coated by a spinner onto the exterior surface of the base plate of the CRT to produce a transparent, electro-conductive layer. The coated surface is heated after the application of the tin oxide layer for about thirty minutes at a temperature in the range of 100.degree. C. to 200.degree. C. Thereafter, a second layer of ultra-fine 50 nm diameter silicon oxide particles suspended in a solution of ethyl silicate and ethanol is coated onto the first layer by a spinner to produce a non-glare layer with antistatic properties. The CRT tube with the two layers of particles are again heated for about thirty minutes at temperatures in the range of 100.degree. C. to 200.degree. C.
U.S. Pat. No. 4,563,612 to Deal, et al. describes a cathode ray tube having an antistatic, glare-reducing coating. The coating has a rough surface which is composed essentially of a silicate material and an inorganic metallic compound The coating is applied by spraying a solution of a water soluble salt of one or more of a metal selected from platinum, tin, palladium and gold in a lithium stabilized silica sol onto the surface of the cathode ray tube. A solution of lithium, sodium and potassium silicate or an organic silicate, such as tetraethyl orthosilicate may be substituted for the lithium stabilized silica sol.
U.S. Pat. No. 4,582,761 to Liu discloses an aqueous dispersion of polyvinyl acetate for use as a coating on an electronic viewing screen to provide antiglare properties.
U.S. Pat. No. 3,689,3I2 to Long, et al. is directed to a method for producing a glare-reducing coating on the surface of a cathode ray tube. The method includes the steps of preparing a coating formulation consisting of a solution of a siliceous polymer and an organic polymer in a volatile organic liquid vehicle for the polymers. The solution is then sprayed onto the surface of a cathode ray tube to coat the surface. The cathode ray tube is then baked at a temperature of 100.degree. C. to 200.degree. C. to cure the coating.
A cathode ray tube having an antistatic film is disclosed in U.S. Pat. No. 4,785,217 to Matsuda, et al. The antistatic film is applied by dipping the cathode ray tube into a mixture of tetraethyl silicate, propanol and butanol containing a colloidal solution of metal particles.
It is known to apply a solution of tetrachlorosiliane in an anhydrous alcohol to the surface of a CRT heated to 50.degree. C. to 80.degree. C. to reduce glare. The tube surface is then heated to a temperature up to 200.degree. C. for 15-20 minutes to cause polymerization of the silane to a polysiloxane. In this method, the silane solution is sprayed onto the surface of the CRT in the form of discrete island droplets of the solution. A continuous film of the solution must be avoided to provide optimum antiglare properties.
It is also known to apply coatings of lithium silicate onto the surface of a CRT to provide antiglare properties.
While various prior art methods have been proposed for reducing gloss and providing antiglare properties to the surface of a CRT, such methods have not met with complete success. It is important that any coating provided on the surface of the CRT to reduce gloss does not impart undesirable side effects, such as the provision of a mottled or uneven surface. The diffusive reflectivity of the surface imparted by the coating should also not be substantially different than that of the uncoated CRT.
US Referenced Citations (6)
Continuation in Parts (1)
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Number |
Date |
Country |
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558993 |
Jul 1990 |
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Patent Grant
5150004
