Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
  • H01J9/20—Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
  • H01J9/22—Applying luminescent coatings
  • H01J9/227—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
  • H01J9/20—Manufacture of screens on or from which an image or pattern is formed, picked up, converted or stored; Applying coatings to the vessel
  • H01J9/22—Applying luminescent coatings
  • H01J9/227—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines
  • H01J9/2271—Applying luminescent coatings with luminescent material discontinuously arranged, e.g. in dots or lines by photographic processes

Definitions

• the invention relates to a method for producing fluorescent screens for cathode ray tubes by applying a pattern made of luminous pigments to the inside of the screen support made of glass.
• it relates to a method for fixing the luminous pigment pattern on the glass faceplate.
• luminous pigments have to be applied to the inside of the screen in the form of relatively fine patterns.
• To create these patterns one starts from the light patterns that are easily available with the shadow mask and converts them into luminous pigment patterns using light-sensitive, mostly organic substances or preparations.
• this process must be carried out separately for each pigment.
• phototackifiable materials There are also known substances and preparations which become sticky on exposure (so-called phototackifiable materials). These are preferred because they enable the production of color picture screens by means of only one light-sensitive layer.
• the organic components must be removed from the luminescent pigment layer by heating or by a dissolving process before the cathode ray tube is finished, in order to ensure a stable vacuum in the finished tube.
• the object of the invention is to provide a method with which the luminous pigment pattern can be fixed on the faceplate after the photosensitive material has been removed without the pattern or the glass faceplate being damaged.
• Another object of the invention is to provide a method which leads to fluorescent screens with good optical properties.
• the new process should be able to be carried out at temperatures below 300 ° C and without an additional drying step. This object is achieved by the method described in the characterizing part of the main claim.
• the luminescent pigment patterns can be fixed on the screen support if, after removal of the photosensitive substance, they are alternately repeated at a temperature below 300 ° C. in an atmosphere which contains a hydrolysis-sensitive gaseous silicon compound and an atmosphere which contains water vapor , suspends.
• Suitable hydrolysis-sensitive silicon compounds are primarily those compounds which have a vapor pressure of 30 hPa at the working temperature. Examples of such compounds are silicon tetrachloride, hexachlorodisilane, silicon tetrabromide, trichlorosilane and tribosilane. Silicon tetrachloride is preferred for working temperatures below 100 ° C.
• the working temperature is below 300 ° C. This prevents the glass support of the luminescent screen from deforming or losing its hardening. However, it is preferably carried out at 20 to 50 ° C.
• Air is preferably used as the carrier gas for the atmospheres, which contain vapors of the reaction partners, and is appropriately dried before being mixed with the vapor of the hydrolysis-sensitive silicon compound.
• any other gases which are inert with respect to the reactants in the temperature range of the working process for example nitrogen, argon or mixtures of such gases.
• Suitable light-sensitive organic substances are preferably those which become tacky on exposure or lose their tackiness which is present at the beginning. Layers of these substances can be toned with the after the exposure of the light pattern powdered luminous pigment can be provided with the desired luminous pigment pattern. Suitable substances can be found, for example, in patent publications DE 12 10321, DE 19 04 059, DE 1944311, DE 2758209, DE 28 15894, DE 3023247, DE 3048490 and DE 3429615.
• the luminescent pigments can also be mixed with substances that change their solubility in a suitable solvent by exposure to light.
• the luminous pigment pattern is formed in layers of such mixtures by exposing the light pattern and washing it out.
• the light-sensitive organic substances are removed.
• this can be done by heating under reduced pressure.
• the method according to the invention makes it possible to fix luminous pigments loosely adhering to glass screen supports without any mechanical action on them. This prevents damage to the pigment pattern.
• the powder according to the invention achieves uniform fixation; the strength of the fixation can easily be adapted to the needs by changing the number of cycles. In general, a small number of cycles, for example 2 to 5, is sufficient to anchor the pigment pattern sufficiently firmly. There is no additional drying step. For these reasons, the method according to the invention can work much faster than according to the prior art.
• luminescent screens of high optical quality and high emission are obtained.
• the invention is used in the manufacture of fluorescent screens for cathode ray tubes, in particular for color television tubes.
• the screen was treated with methyl ethyl ketone vapor analogously to the process described in EP 01 92 301 - A2, p.7.
• the dried screen was placed on a flat base plate, which was provided with openings for the supply of air silicon tetrachloride vapor and moist air and for the removal of the used gases, and formed a reaction chamber of about 4 l with the screen.
• the gap between the screen and the base plate was sealed with elastic material.

Landscapes

• Engineering & Computer Science (AREA)
• Manufacturing & Machinery (AREA)
• Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
• Luminescent Compositions (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

Family

ID=6369792

Family Applications (1)

Country Status (5)

Citations (1)

Family Cites Families (5)

• 1988
  • 1988-12-22 DE DE3843157A patent/DE3843157C1/de not_active Expired - Fee Related
• 1989
  • 1989-12-21 JP JP90501727A patent/JPH04503130A/ja active Pending
  • 1989-12-21 WO PCT/EP1989/001589 patent/WO1990007189A1/de not_active Ceased
  • 1989-12-21 KR KR1019900701818A patent/KR910700537A/ko not_active Withdrawn
  • 1989-12-21 EP EP90900826A patent/EP0449914A1/de not_active Withdrawn

Patent Citations (1)

Also Published As

Similar Documents

Legal Events