US3899709A - Cathode ray tube acoustic transducers - Google Patents

Cathode ray tube acoustic transducers Download PDF

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Publication number
US3899709A
US3899709A US479128A US47912874A US3899709A US 3899709 A US3899709 A US 3899709A US 479128 A US479128 A US 479128A US 47912874 A US47912874 A US 47912874A US 3899709 A US3899709 A US 3899709A
Authority
US
United States
Prior art keywords
layer
envelope
faceplate
acoustic transducer
transducer according
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US479128A
Other languages
English (en)
Inventor
Patrick Harold Brown
Raymond Frank Sivyer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EMI Ltd
Original Assignee
EMI Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EMI Ltd filed Critical EMI Ltd
Application granted granted Critical
Publication of US3899709A publication Critical patent/US3899709A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/495—Pick-up tubes adapted for an input of sonic, ultrasonic, or mechanical vibrations and having an electric output

Definitions

  • An acoustic transducer comprises a cathode ray tube which has an acoustically transmissive faceplate and a layer of piezoelectric material, disposed internally of the tube supported by the faceplate.
  • a layer of resilient material, which is acoustically transmissive and vacuum compatible is interposed between the layer of piezoelectric material and the faceplate to provide vibrational decoupling between them.
  • the sensing element usually a quartz piezoelectric target
  • a vacuum-sealed support window whose physical properties are compatible with vacuum environment and processing, transmission of ultrasonic radiation, and the thermal expansion of the sensing element.
  • a cathode ray tube acoustic transducer including,
  • signal electrode means for deriving electrical output signals from said transducing layer indicative of the spatial variations of pressure applied thereto and g. an acoustically transmissive layer of resilient material separating and in contact with said faceplate and said transducing layer.
  • FIGURE illustrates diagrammatically a sectional view of a cathode ray tube in accordance with the invention.
  • a cathode ray tube has an envelope 1, of good ductile metal such as copper or aluminium.
  • the envelope may be of vitreous material, eg glass.
  • a conventional electron gun 2 produces a beam of electrons for scanning across the target. The electron beam may be focused and scanned in conventional manner by electrostatic or electromagnetic means indicated generally at 13.
  • a conventional wall anode 8 may be provided, with an electrical connection 4. Pins such as 11 are mutually insulated and hermetically sealed by bushes such as 12 through the envelope for effecting electrical connections to the various internal electrodes.
  • the envelope 1 is hermetically sealed to a faceplate 3 by means of a groove 7.
  • the faceplate is formed of a rigid material which will transmit the ultrasonic radiation image for which the device is employed.
  • the terminal expansion coefficients of the faceplate, envelope and, if used, sealing material must be matched to avoid the introduction of thermal stresses which might lead to the breakdown of the hermetic seal. Suitable plastics materials for the faceplate are given by way of example in the aforementioned co-pending patent application.
  • the faceplate 3 may comprise Pyrex.
  • a tessellated target structure comprising plates such as 6 of piezoelectric material.
  • the plates 6 may comprise X-cut crystals of quartz, spaced from each other to allow for expansion.
  • the plates 6 are of a thickness such as to achieve half wave acoustic resonance therein. For example, for use with ultrasonic sound waves having a frequency of 2 MHz, the thickness of the plates 6 would be 1.43 mm.
  • the target includes a signal electrode 5 and a hermetically sealed lead 9. I
  • a resilient layer 10 is interposed between the target and the faceplate.
  • the resilient layer 10 comprises a material which allows the ultrasonic energy to pass through to the target and cause the piezoelectric plates 6 to vibrate in the planar mode while at the same time providing sufficient vibrational decoupling between the plates 6 and the faceplate 3.
  • the layer 10 must also be vacuum compatible so as not to adversely affect the vacuum in the cathode ray tube, and it must also be able to withstand tube processing such as baking.
  • a resilient layer 10 comprising a layer of Viton rubber 0.8mm thick has been found most suitable.
  • the introduction of the resilient layer 10 causes a mismatch of acoustic impedances, sufficient ultrasonic energy is transmitted to the plates 6.
  • the vibrational decoupling provided by the resilient layer 10 allows the resolution to be retained since the plates 6 and the faceplate 3 do not vibrate as a single unit.
  • the resilience of the layer 10 also accommodates the differential thermal expansion encountered during vacuum process baking and, if required, the hot curing schedule for adhesives.
  • the surfaces of the piezoelectric plates 6 are stabilized at some suitable potential by scanning them with the electron beam.
  • the plates 6 are caused to vibrate in the planar mode in dependance upon the distribution of the ultra-sonic energy in the image. This causes a correspondingly distributed variation in the charge on the stabilized surfaces of the plates.
  • the plates are then re-scanned to re-stabilize the surfaces, and in so doing, capacitive coupling produces signals in the signal electrode 5 which correspond to the distribution of the ultra-sonic energy in the image.
  • the piezoelectric target may comprise material other than quartz, and may take forms other than a tessellated structure.
  • other resilient materials may be employed for the layer 10.
  • the envelope can conveniently be sealed to the faceplate 3 by extending the layer 10 beyond the periphery, of the envelope, and clamping the envelope to the faceplate so as to compress the extended part of the layer 10 between the end of the envelope and the faceplate.
  • the compression of the layer 10 produces an adequate seal, and moreover the presence of the Viton rubber between the envelope 1 and the faceplate l permits differential expansion to occur between the two elements.
  • a cathode ray tube acoustic transducer including,
  • an electron gun mounted within said envelope for providing a beam of electrons directed toward said transducing layer
  • signal electrode means for deriving electrical outranged such that part of said layer of resilient material may be compressed between said faceplate and said envelope to provide a hermetic seal.

Landscapes

  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Transducers For Ultrasonic Waves (AREA)
US479128A 1973-01-11 1974-06-13 Cathode ray tube acoustic transducers Expired - Lifetime US3899709A (en)

Applications Claiming Priority (5)

Application Number Priority Date Filing Date Title
GB146673 1973-01-11
GB146573*[A GB1447984A (en) 1973-01-11 1973-01-11 Acoustic transducers
GB1587373 1973-04-03
GB4151273 1973-09-04
GB5075273 1973-11-01

Publications (1)

Publication Number Publication Date
US3899709A true US3899709A (en) 1975-08-12

Family

ID=27515680

Family Applications (1)

Application Number Title Priority Date Filing Date
US479128A Expired - Lifetime US3899709A (en) 1973-01-11 1974-06-13 Cathode ray tube acoustic transducers

Country Status (6)

Country Link
US (1) US3899709A (de)
JP (1) JPS5030414A (de)
DE (1) DE2401356A1 (de)
FR (1) FR2324118A1 (de)
GB (1) GB1447984A (de)
NL (1) NL7400372A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4103203A (en) * 1974-09-09 1978-07-25 Rca Corporation Wafer mounting structure for pickup tube
US6188160B1 (en) 1997-09-12 2001-02-13 University Of Kentucky Research Foundation Smart material control system and related method
US6297579B1 (en) 2000-11-13 2001-10-02 Sandia National Laboratories Electron gun controlled smart structure
US20050212868A1 (en) * 2004-03-26 2005-09-29 Radominski George Z Fluid-ejection device and methods of forming same

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5281887A (en) * 1992-06-15 1994-01-25 Engle Craig D Two independent spatial variable degree of freedom wavefront modulator

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3325777A (en) * 1964-08-26 1967-06-13 Litton Prec Products Inc Image forming apparatus
US3505558A (en) * 1966-09-22 1970-04-07 John E Jacobs Composite target structure for television,x-ray and ultrasound camera tube
US3594583A (en) * 1966-08-22 1971-07-20 Sheldon Edward E Electro-optical devices for detecting images of invisible radiations using interaction of light beams
US3622825A (en) * 1969-03-24 1971-11-23 Litton Systems Inc Mosaic acoustic transducer for cathode-ray tubes

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3325777A (en) * 1964-08-26 1967-06-13 Litton Prec Products Inc Image forming apparatus
US3594583A (en) * 1966-08-22 1971-07-20 Sheldon Edward E Electro-optical devices for detecting images of invisible radiations using interaction of light beams
US3505558A (en) * 1966-09-22 1970-04-07 John E Jacobs Composite target structure for television,x-ray and ultrasound camera tube
US3622825A (en) * 1969-03-24 1971-11-23 Litton Systems Inc Mosaic acoustic transducer for cathode-ray tubes

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4103203A (en) * 1974-09-09 1978-07-25 Rca Corporation Wafer mounting structure for pickup tube
US6188160B1 (en) 1997-09-12 2001-02-13 University Of Kentucky Research Foundation Smart material control system and related method
US6297579B1 (en) 2000-11-13 2001-10-02 Sandia National Laboratories Electron gun controlled smart structure
US20050212868A1 (en) * 2004-03-26 2005-09-29 Radominski George Z Fluid-ejection device and methods of forming same
US7334871B2 (en) 2004-03-26 2008-02-26 Hewlett-Packard Development Company, L.P. Fluid-ejection device and methods of forming same

Also Published As

Publication number Publication date
DE2401356A1 (de) 1974-08-08
FR2324118B1 (de) 1978-09-29
FR2324118A1 (fr) 1977-04-08
GB1447984A (en) 1976-09-02
JPS5030414A (de) 1975-03-26
NL7400372A (de) 1974-07-15

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