Dry, impulse-resistant implosion protection system for large screen cathode ray tubes

Claim 2

A large screen cathode ray tube having an improved dry, impulse-resistant implosion protection system, comprising: a glass bulb consisting of a front panel having a faceplate whose inner surface is coated with red-emissive, blue-emissive and green-emissive phosphor elements, and a funnel section terminating in a neck in which one or more electron guns are situated for generating electron beams to illuminate said phosphor elements, said front panel and funnel section being joined together to form an air-tight envelope; a strip of relatively incompressible tape secured to and encircling the bulb and situated on the forward part of the bulb near the faceplate; a first steel tension band placed directly over the tape and tensed to provide hoop compression on the bulb, the opposite ends of said tension band being secured together to prevent relative motion thereof; a second steel tension band placed directly over the first band and also tensed to provide hoop compression on the bulb, the opposite ends of said second tension band being secured together to prevent relative motion thereof, said first and second tension bands being tensed to provide a relatively high cumulative compression on the front panel while having a rigidity and being so tightly secured at their respective ends that when a fracture of the front panel occurs, the resulting tensil strain in each band is small enough to inhibit the propagation of a fracture impulse so as to substantially confine bulb devacuation to the front panel, thus ensuring that a front panel fracture impulse will not propagate to the weaker funnel or neck portions of the bulb until the bulb has been substantially devacuated.

Claim 3

A cathode ray tube as set forth in claim 1 wherein said tape is a relatively hard plastic-impregnated cloth tape having a smooth surface over which said first tension band is placed, said smooth surface acting to enhance the distribution of the hoop compression of the bands and to prevent point loading of the bulb, particularly at the corners thereof, and wherein said tape is relatively hard throughout in order to remain incompressible in the presence of a bulb fracture so that a traveling fracture impulse in the bulb will not be able to compress the tape but will be transmitted by the tape to the tension bands.

Claim 4

A cathode ray tube as set forth in claim 1 wherein each of said tension bands is secured with a heavy duty steel seal for notch-joining their opposite ends to form a non-slip notched joint having a joint strength of approximately 2,500 pounds, thus ensuring a non-yielding, non-slip, joint between opposite ends of each tension band to prevent relative slipping and expansion of the bands during a glass fracture and thereby inhibiting the glass beneath the bands from expanding and transmitting the fracture impulse.

Claim 5

A large screen cathode ray tube having an improved dry impulse-resistant implosion protection system, comprising: a front panel having a faceplate whose inner surface is coated with red-emissive, blue-emissive and green-emissive phosphor elements, and having a flange consisting of a wrap-around skirt protruding rearwardly from the faceplate; a funnel section terminating in a neck in which one or more electron guns are situated for generating electron beams to illuminate said phosphor elements, said front panel and funnel section being joined together to form an airtight envelope; a pressure-adhesive strip of tape encircling the panel skirt and situated on the forward part of the skirt near the faceplate; a first steel tension band placed directly over the tape and tensed to approximately 1,500 pounds so as to provide a hoop compression on the front panel, said band having a breaking tensile strength of approximately 135,000 pounds per square inch and a rigidity which limits the tensile strain of the band to no more than 0.5 percent; a First heavy duty steel seal for notch-joining opposite ends of said first steel tension band to form a notched joint having a joint strength of approximately 2,500 pounds, to thereby prevent relative movement of said tension band ends; a second steel tension band having the aforesaid physical characteristics of said first tension band, tensed to approximately 1,500 pounds, and placed directly over said first steel tension band to provide additional hoop compression on the front panel; a second heavy duty steel seal for notch joining opposite ends of said second steel tension band to form a notched joint having a joint strength of approximately 2,500 pounds to thereby prevent relative movement of the ends of said second tension band, the rigidity of said first and second tension bands and the strength of the notch joints in the bands being such that, when a fracture of the front panel occurs, the resulting tensile strain in each band is small enough to inhibit the propagation of a fracture impulse so as to substantially confine bulb devacuation to the front panel, thus ensuring that a front panel fracture impulse will not propagate to the weaker funnel or neck portions of the bulb until the bulb has been substantially devacuated.

Claim 6

A large screen cathode ray tube having an improved dry impulse-resistant implosion protection system, comprising: a front panel having a faceplate whose inner surface is coated with red-emissive, blue-emissive and green-emissive phosphor elements, and having a flange consisting of a wrap-around skirt protruding rearwardly from the faceplate; a funnel section terminating in a neck in which one or more electron guns are situated for generating electron beams to illuminate said phosphor elements, said front panel and funnel section being joined together to form an airtight envelope; a pressure-adhesive strip of tape encircling the panel skirt and situated on the forward part of the skirt near the faceplate; a first steel tension band placed directly over the tape and tensed to approximately 1,500 pounds so as to provide a hoop compression on the front panel, said band having a breaking tensile strength of approximately 135,000 pounds per square inch and a rigidity which limits the tensile strain of the band to no more than 0.5 percent; a First heavy duty steel seal for notch-joining opposite ends of said first steel tension band to form a notched joint having a joint strength of approximately 2,500 pounds, to thereby prevent relative movement of said tension band ends; a second steel tension band having the aforesaid physical characteristics of said first tension band, tensed to approximately 1,500 pounds, and placed directly over said first steel tension band to provide additional hoop compression on the front panel; a second heavy duty steel seal for notch joining opposite ends of said second steel tension band to form a notched joint having a joint strength of approximately 2,500 pounds to thereby prevent relative movement of the ends of said second tension band, the rigidity of said first and second tension bands and the strength of the notch joints in the bands being such that, when a fracture of the front panel occurs, the resulting tensile strain in each band is small enough to inhibit the propagation of a fracture impulse so as to substantially confine bulb devacuation to the front panel, thus ensuring that a front panel fracture impulse will not propagate to the weaker funnel or neck portions of the bulb until the bulb has been substantially devacuated.

Claim 7

A cathode ray tube as set forth in claim 4, wherein said tape is an approximately 3/4 inch wide by 14 mils thick cloth tape impregnated with plastic to present a relatively hard, smooth surface over which said first tension band may be placed in order to enhance the distribution of the hoop compression of the bands and to prevent point loading of the bulb, particularly at the corners thereof; wherein said tape is relatively hard throughout in order to remain substantially incompressible in the presence of a fracture of the front panel so that a traveling fracture impulse in the front panel will not be able to compress the tape, but will be transmitted by the tape to the tension bands; and wherein said steel tension bands are made of high tensile strength steel having a Young''s modulus of approximately 30 X 106 pounds per square inch and are approximately 3/4 inch wide by 31 mils thick.