US3879700A - Device for converting an acoustic pattern into a visual image - Google Patents

Device for converting an acoustic pattern into a visual image Download PDF

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Publication number
US3879700A
US3879700A US314313A US31431372A US3879700A US 3879700 A US3879700 A US 3879700A US 314313 A US314313 A US 314313A US 31431372 A US31431372 A US 31431372A US 3879700 A US3879700 A US 3879700A
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United States
Prior art keywords
acoustic
pattern
electron
converting
electron current
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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
US314313A
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English (en)
Inventor
Sarkis Barkhoudarian
Charles Bruce Johnson
George G Goetz
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.)
Bendix Corp
Original Assignee
Bendix Corp
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 Bendix Corp filed Critical Bendix Corp
Priority to US314313A priority Critical patent/US3879700A/en
Priority to GB5425873A priority patent/GB1407156A/en
Priority to FR7342473A priority patent/FR2210324A6/fr
Priority to NL7316659A priority patent/NL7316659A/xx
Priority to DE2361116A priority patent/DE2361116A1/de
Priority to JP48137879A priority patent/JPS4990434A/ja
Application granted granted Critical
Publication of US3879700A publication Critical patent/US3879700A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
    • G01H3/00—Measuring characteristics of vibrations by using a detector in a fluid
    • G01H3/10—Amplitude; Power
    • G01H3/12—Amplitude; Power by electric means
    • G01H3/125—Amplitude; Power by electric means for representing acoustic field distribution
    • 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
    • H01J31/50—Image-conversion or image-amplification tubes, i.e. having optical, X-ray, or analogous input, and optical output
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2231/00—Cathode ray tubes or electron beam tubes
    • H01J2231/50—Imaging and conversion tubes
    • H01J2231/50005—Imaging and conversion tubes characterised by form of illumination
    • H01J2231/50052—Mechanical vibrations, e.g. sound
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2231/00—Cathode ray tubes or electron beam tubes
    • H01J2231/50—Imaging and conversion tubes
    • H01J2231/50057—Imaging and conversion tubes characterised by form of output stage
    • H01J2231/50063—Optical
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2231/00—Cathode ray tubes or electron beam tubes
    • H01J2231/50—Imaging and conversion tubes
    • H01J2231/501—Imaging and conversion tubes including multiplication stage
    • H01J2231/5013—Imaging and conversion tubes including multiplication stage with secondary emission electrodes
    • H01J2231/5016—Michrochannel plates [MCP]

Definitions

  • An acoustic pattern imaged on a piezoelectric transducer is converted to an electronic charge pattern.
  • a source of electrons such as a photocathode illuminated by a radiation source, is closely associated with the transducer and electrons are liberated in accordance with the pattern.
  • the electrons are multiplied by a microchannel plate electron multiplier and are converted into photon energy by a phosphor screen to provide a visual image of the acoustic pattern.
  • a grid is positioned between the piezoelectric transducer and the microchannel plate electron multiplier and is maintained at a potential so that the average electron current varies in accordance with the acoustic input.
  • PHENTEU APR 2 2 i575 SHEET 2 of '3 omuzu i 1 SNOHLOBIH :D BBBWON uaauris HOHdSOHd 1v maaana Nouns-13 A ssaumslua uaauas aoHdsoHd CURRENT PATENTEBAPR22I915 3,879 700 sum 3 9 "3 III II CURRENT THROUGH GRID VERSUS GRID BIAS VOLTAGE FOR A Cs I PHOTOCATHODE Vg 0. 925v 0.00: l 1
  • the invention relates to a device for converting an acoustic pattern to a visual image.
  • Devices as used heretofore for converting an acoustic pattern to a visual image used an electron gun for scanning the acoustic pattern and the resulting current was amplified and converted to a visual picture using scanning techniques. Such a device was complicated and relatively large in size and required adequate power to operate.
  • the present application is an improvement on copending application Ser. No. 3 4,314 assigned to the same assignee as the present application and provides an improved visual image by biasing the electron cur rent so that the average electron current varies in accordance with the acoustic input.
  • the invention contemplates a device for converting an acoustic pattern into a visual image, comprising a piezoelectric transducer for receiving the acoustic pattern and providing an electronic charge pattern corresponding thereto, a source of electrons associated with the piezoelectric transducer for providing an electron current, means for biasing the electron current so that the electronic charge pattern modulates the electron current to provide an average electron current which varies in accordance with the acoustic input, a microchannel plate electron multiplier for amplifying the modulated electron current, and means for converting the amplified electron current to a visual image corresponding to the acoustic pattern.
  • One object of the present invention is to provide a device for converting an acoustic pattern to an electrical current pattern directly without the use of an electron gun or video processing.
  • Another object of the invention is to provide a device for converting an acoustic pattern into an electron current pattern for remote readout, that is, display and/or storage.
  • Another object of the invention is to use a piezoelectric transducer for providing an electronic charge or voltage pattern corresponding to an acoustic pattern imaged on the piezoelectric transducer.
  • Another object of the invention is to provide a spatial electron current modulated by the voltage pattern by illuminating a photocathode from a radiation source and using a microchannel plate electron multiplier for amplifying the electron current.
  • Another object is to utilize a phosphorous screen for converting the amplified electron current to photon energy to provide a visual image of the acoustic pattern.
  • a more specific object of the invention is to bias the electron current so that the electron current is modulated by the acoustic pattern to provide an average electron current which varies in accordance with the acoustic input.
  • FIG. I is a schematic diagram of a device constructed according to the invention for con verting an acoustic pattern to a visual image.
  • FIG. 2 shows the energy distribution of electrons emitted from a Cesium Iodide photocathode
  • FIG. 3 shows the electron current at the input of each channel in the microchannel plate electron multiplier from a Cesium Iodide photocathode plotted as ordinate in logarithmic scale and bias voltage plotted linearly as abscissa.
  • FIG. 4 is a schematic diagram showing the phosphorous screen brightness distribution resulting from a square wave acoustic pattern
  • FIG. 5 is a perspective view of a device constructed according to the invention.
  • FIG. 6 shows how modulation varies as a function of grid bias.
  • FIG. 1 a novel converter constructed according to the invention is shown in FIG. 1 as comprising a piezoelectric transducer 1, such as a quartz crystal or barium titanate ceramic.
  • a piezoelectric transducer such as a quartz crystal or barium titanate ceramic.
  • An acoustic pattern shown by broken line arrows, is imaged by an acoustic lens 2 on the piezoelectric transducer and a corresponding electronic charge or voltage pattern is formed on the transducer as shown by the plus and minus signs.
  • the transducer has a photocathode 3 asso ciated therewith, preferably on one surface, and the photocathode is uniformly illuminated by a radiation source, such as ultraviolet, infrared, electromagnetic or radio active, as shown by the solid line arrows.
  • the photocathode may be Cesium Iodide which has a nonlinear electron energy distribution.
  • the irradiated photocathode 3 is a source of photoelectrons, and electrons are released from the photo cathode having a spatial distribution of electron energies corresponding to the acoustic input pattern.
  • a grid in the form ofa fine mesh 5 is positioned adjacent the photocathode and is maintained at a potential V,, to provide an average electron current I' which varies in accordance with the acoustic input.
  • the grid voltage may vary between approximately eight tenths (0.8) volt and 0.950 volt below the potential of the piezoelectric transducer and photocathode which may be at ground potential.
  • grid 5 passes the higher energy electrons and repels the lower energy electrons as shown by the dotted line arrows and the electron current passing through the grid is modulated by the acoustic pattern and has an average value which varies in accordance with the acoustic input.
  • the modulated electron current is linearly amplified by a microchannel plate electron multiplier 7, as shown by the dash-dot arrows, and the spatially distributed current from the microchannel plate is imaged on a high potential phosphorous screen 9 where it is converted to photon energy to provide a visual image of the acoustic pattern.
  • the input potential V,- of the microchannel plate is maintained at about 300 volts higher than the grid potential V, and the output potential V of the microchannel plate electron multiplier is adjusted to give the required gain and may be approximately 1,000 volts higher than V
  • the phosphorous screen potential V is about 5.000 volts higher than V In some instances it may be desirable to avoid using a separate grid in the form of a fine mesh and instead maintain the input face of the microchannel plate at the potential V, to modulate the electron current as described above.
  • FIG. 2 shows the non-linear energy distribution of electrons emitted from an irradiated Cesium Iodide photocathode. The number of electrons is plotted as the ordinate and the energy of the electrons is plotted as the abcissa.
  • the dotted line shows the energy distribution of the electrons in the absence of an acoustic pattern and the solid lines show the energy distributions of the electrons when modulated by the acoustic pattern with a maximum variation of V,,, volts.
  • Electron currents correspond to the areas under the curves.
  • the grid potential V preferably is selected so that modulation of the electron current from the photocathode by the electronic charge pattern occurs in the non-linear region of the curves so that the average electron current I varies in accordance with the acoustic input.
  • FIG. 3 the electron current I through the grid for each element of the Cesium Iodide photocathode is plotted in logarithmic scale as the ordinate for various grid bias voltages V plotted in linear scale as the abcissa.
  • a grid voltage of 0.925 volts and an input sine voltage V from the quartz crystal having am amplitude and frequency of the acoustic input an electron output current I which varies from 0.00l5 to 0.0070 passes through the grid.
  • the average electron current I' shown by the dotted lines has a value of 0.0043.
  • the current I shown by the solid line has a value of 0.0035 and is the average current when the input voltage V from the quartz crystal is zero, that is, I is the average current without an acoustic input.
  • the modulation M is 0. l0 and is given by the following equation:
  • the acoustic-waveinduced piezoelectric modulation voltage, the grid bias potential, the wavelength distribution of the radiation source, and the emitted electron energy distribution is chosen to maximize the difference between I' and I.
  • a suitable balance must be maintained between tube brightness as determined by the average electron current I and the modulation.
  • the grid voltage V is 0.85 volts and the electron current L, varies between 0.032 and 0.013 and the average electron current I' is 0.023.
  • I equals 0.02I and M is equal to 0.04.
  • the grid voltage V is 0.75 volts and the electron current I varies between 0.090 and 0.058.
  • the average current I is the same as l and is equal to 0.074 and the modulation M is zero.
  • FIG. 6 shows that the modulation M increases as the grid bias V, increases negatively. Even greater modulation M and better contrast can be obtained by increasing the negative bias V so that the lower portions of the electron current I are cut off to increase the difference between the average currents I and I. This can be done by increasing V negatively to about 0.950 volts.
  • the grid voltages are selected so that modulation of the electron current by the acoustic input occurs on the non-linear portion of the electron current curve and M is greater than zero.
  • the phosphorous screen brightness distribution for a square wave acoustic pattern is shown in FIG. 4.
  • the waves show the instantaneous electron current to the phosphorous screen due to acoustic modulation and the amplitude and frequency of the acoustic input.
  • the average screen brightness due to emission produced by the radiation source and modulation of the electron current by an acoustic input is shown by the line B and the screen brightness due to photocathode emission produced by the radiation source only is shown by the line B,,.
  • the resulting modulation (M) in the phosphor screen brightness (FIG. 4) is given by the equation:
  • the acoustic pattern may have any desired frequency (such as subsonic, sonic or ultrasonic) given by the equation:
  • the conductivity of the photocathode should be great enough to allow the photocathode current to remain at equilibrium with the piezoelectric modulation potential, but small enough to eliminate image quality degradation due to charge conduction.
  • the values of the volume resistivity (p) and permitivity (e) of the photocathode material should be such that the characteristic time constant (7) of the photocathode is much larger than the applied acoustical period:
  • f is the applied acoustical frequency
  • a device constructed according to the invention for converting an acoustic pattern into a visual image may be packaged in an evacuated circular envelope as shown in FIG. 5.
  • the envelope need not be more than several inches in diameter and less than an inch thick. In some instances it may be desirable to incorporate the device in a compact package, e.g., goggles, for underwater detection of acoustic patterns.
  • a direct-view visual image of an acoustic input image is produced at the phosphorous screen.
  • a device for converting an acoustic pattern into a visual image comprising a piezoelectric transducer for receiving the acoustic pattern and providing an electronic charge pattern corresponding thereto, a source of electrons associated with the piezoelectric transducer for providing an electron current, means for biasing the electron current at a potential to provide an electron current modulated by the electronic charge pattern and having an average which varies in accordance with the acoustic pattern, a microchannel plate electron multiplier for amplifying the modulated electron current, and means for converting the amplified electron current to a visual image corresponding to the acoustic pattern.
  • a device for converting an acoustic pattern into a visual image as described in claim I in which the source of electrons includes a photocathode and a radiation source for irradiating the photocathode.
  • a device for converting an acoustic pattern into a visual image as described in claim I in which the image converting means comprises a phosphorous screen for converting the amplified electron current to photon energy for providing the visual image.
  • a device as described in claim 2 in which the grid is maintained at a potential to repel low energy electrons and pass high energy electrons.
  • microchannel plate electron multiplier has input and output electrodes at a potential for the required gain and the potential of the input electrode is several hundred volts higher than the grid potential.
  • a device as described in claim 5 in which the charge pattern voltage, the biasing potential, the wavelength distribution of the radiation source, and the photocathode spectral response cooperate to provide nonlinear modulation of the electron current.
  • a device as described in claim 1 which includes means for imaging the acoustic pattern on the piezoelectric transducer.
  • a device for converting an acoustic pattern into a visual image as described in claim 15 in which the biasing potential causes the electronic charge pattern to modulate the electron current in a non-linear region.
  • a device for converting an acoustic input into a visual image comprising a piezoelectric transducer, means for imaging the acoustic input on the piezoelectric transducer for providing an electronic charge pattern corresponding thereto, a photocathode having a non-linear electron energy distribution associated with the piezoelectric transducer, a radiation source for irradiating the photocathode to provide a source of electrons, a grid postitioned adjacent the photocathode and maintained at a potential to bias the electron current at a level of nonlinear electron energy distribution to provide an electron current modulated by the electronic charge pattern and having a spatial distribution of electron energies corresponding to the acoustic pattern, a microchannel plate electron multiplier positioned adjacent the grid for amplifying the modulated electron current, and a phosphorous screen positioned adjacent the microchannel plate electron multiplier for converting the electron current therefrom to photon energy for providing a visual image of the acoustic input.
  • a device for converting an acoustic input into a visual image as described in claim 17 in which the grid is maintained at a potential to provide an electron current modulated by the electronic charge pattern and having an average which varies in accordance with the acoustic input.
  • a device for converting an acoustic input into a spatial electron current comprising a piezoelectric transducer for receiving the acoustic input and providing an electronic charge pattern corresponding thereto, a source of electrons associated with the piezoelectric transducer for providing an electron current, means for biasing the electron current at a potential to provide an electron current modulated by the electron charge pattern and having an average which varies in accordance with the acoustic input, and a microchannel plate elec tron multiplier for amplifying the modulated electron current.
  • biasing means includes means for maintaining the grid at a potential below the potential of the source of electrons.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • General Physics & Mathematics (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Transforming Light Signals Into Electric Signals (AREA)
US314313A 1972-12-12 1972-12-12 Device for converting an acoustic pattern into a visual image Expired - Lifetime US3879700A (en)

Priority Applications (6)

Application Number Priority Date Filing Date Title
US314313A US3879700A (en) 1972-12-12 1972-12-12 Device for converting an acoustic pattern into a visual image
GB5425873A GB1407156A (en) 1972-12-12 1973-11-22 Device for converting an acoustic pattern into a visual image
FR7342473A FR2210324A6 (de) 1972-12-12 1973-11-29
NL7316659A NL7316659A (de) 1972-12-12 1973-12-05
DE2361116A DE2361116A1 (de) 1972-12-12 1973-12-07 Vorrichtung zum umwandeln eines akustischen zeichens oder bildes in ein sichtbares zeichen oder bild
JP48137879A JPS4990434A (de) 1972-12-12 1973-12-12

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Application Number Priority Date Filing Date Title
US314313A US3879700A (en) 1972-12-12 1972-12-12 Device for converting an acoustic pattern into a visual image

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US (1) US3879700A (de)
JP (1) JPS4990434A (de)
DE (1) DE2361116A1 (de)
FR (1) FR2210324A6 (de)
GB (1) GB1407156A (de)
NL (1) NL7316659A (de)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3996552A (en) * 1975-04-28 1976-12-07 The Bendix Corporation Device for providing a hologram of an insonified object
WO1982004352A1 (en) * 1981-06-01 1982-12-09 Kodak Co Eastman High resolution optical-addressing apparatus
EP0586144A1 (de) * 1992-08-21 1994-03-09 Sharp Kabushiki Kaisha Photoemissionvorrichtung
US20100058870A1 (en) * 2008-09-10 2010-03-11 Canon Kabushiki Kaisha Photoacoustic apparatus

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001319565A (ja) * 2000-05-11 2001-11-16 Hamamatsu Photonics Kk 光電陰極

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2739243A (en) * 1953-01-08 1956-03-20 Sheldon Edward Emanuel Composite photosensitive screens
US2816236A (en) * 1956-06-19 1957-12-10 Gen Electric Method of and means for detecting stress patterns
US2855531A (en) * 1957-01-04 1958-10-07 Rca Corp Electroluminescent devices and systems
US2903617A (en) * 1957-06-20 1959-09-08 William R Turner Electronic ultrasonic image converter
US3243508A (en) * 1963-03-22 1966-03-29 Nuclear Corp Of America Resonance electroluminescent display panel
US3505558A (en) * 1966-09-22 1970-04-07 John E Jacobs Composite target structure for television,x-ray and ultrasound camera tube
US3603828A (en) * 1969-01-28 1971-09-07 Sheldon Edward E X-ray image intensifier tube with secondary emission multiplier tunnels constructed to confine the x-rays to individual tunnels
US3622825A (en) * 1969-03-24 1971-11-23 Litton Systems Inc Mosaic acoustic transducer for cathode-ray tubes
US3675028A (en) * 1969-08-13 1972-07-04 Itt Image intensifier with electroluminescent phosphor
US3716740A (en) * 1970-09-18 1973-02-13 Bell Telephone Labor Inc Photocathode with photoemitter activation controlled by diode array
US3742284A (en) * 1971-04-02 1973-06-26 Us Navy Ultrasonic camera tube

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2739243A (en) * 1953-01-08 1956-03-20 Sheldon Edward Emanuel Composite photosensitive screens
US2816236A (en) * 1956-06-19 1957-12-10 Gen Electric Method of and means for detecting stress patterns
US2855531A (en) * 1957-01-04 1958-10-07 Rca Corp Electroluminescent devices and systems
US2903617A (en) * 1957-06-20 1959-09-08 William R Turner Electronic ultrasonic image converter
US3243508A (en) * 1963-03-22 1966-03-29 Nuclear Corp Of America Resonance electroluminescent display panel
US3505558A (en) * 1966-09-22 1970-04-07 John E Jacobs Composite target structure for television,x-ray and ultrasound camera tube
US3603828A (en) * 1969-01-28 1971-09-07 Sheldon Edward E X-ray image intensifier tube with secondary emission multiplier tunnels constructed to confine the x-rays to individual tunnels
US3622825A (en) * 1969-03-24 1971-11-23 Litton Systems Inc Mosaic acoustic transducer for cathode-ray tubes
US3675028A (en) * 1969-08-13 1972-07-04 Itt Image intensifier with electroluminescent phosphor
US3716740A (en) * 1970-09-18 1973-02-13 Bell Telephone Labor Inc Photocathode with photoemitter activation controlled by diode array
US3742284A (en) * 1971-04-02 1973-06-26 Us Navy Ultrasonic camera tube

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3996552A (en) * 1975-04-28 1976-12-07 The Bendix Corporation Device for providing a hologram of an insonified object
WO1982004352A1 (en) * 1981-06-01 1982-12-09 Kodak Co Eastman High resolution optical-addressing apparatus
EP0586144A1 (de) * 1992-08-21 1994-03-09 Sharp Kabushiki Kaisha Photoemissionvorrichtung
US6057639A (en) * 1992-08-21 2000-05-02 Sharp Kabushiki Kaisha Photoemission apparatus with spatial light modulator
US20100058870A1 (en) * 2008-09-10 2010-03-11 Canon Kabushiki Kaisha Photoacoustic apparatus
US8397573B2 (en) * 2008-09-10 2013-03-19 Canon Kabushiki Kaisha Photoacoustic apparatus

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Publication number Publication date
NL7316659A (de) 1974-06-14
GB1407156A (en) 1975-09-24
FR2210324A6 (de) 1974-07-05
JPS4990434A (de) 1974-08-29
DE2361116A1 (de) 1974-06-20

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