US3705324A - Fluorescent display tubes - Google Patents

Fluorescent display tubes Download PDF

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Publication number
US3705324A
US3705324A US183054A US3705324DA US3705324A US 3705324 A US3705324 A US 3705324A US 183054 A US183054 A US 183054A US 3705324D A US3705324D A US 3705324DA US 3705324 A US3705324 A US 3705324A
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US
United States
Prior art keywords
electrons
fluorescent display
display tube
phosphor
insulator base
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
US183054A
Other languages
English (en)
Inventor
Mitsuru Masuda
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.)
Noritake Itron Corp
Original Assignee
Ise Electronics 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
Priority claimed from JP9483570U external-priority patent/JPS4914286Y1/ja
Priority claimed from JP9483470U external-priority patent/JPS4914285Y1/ja
Application filed by Ise Electronics Corp filed Critical Ise Electronics Corp
Application granted granted Critical
Publication of US3705324A publication Critical patent/US3705324A/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
    • H01J29/18—Luminescent screens
    • 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
    • H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
    • H01J31/12—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen
    • H01J31/15—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen with ray or beam selectively directed to luminescent anode segments

Definitions

  • ABSTRACT In a fluorescent display tube of the type comprising an insulator base having a plurality of recess 45 84 33 00 88 44 In NH Bk 5s 1 0 s m m" 5 u. a n n n mm 0 n mm m QM m .t mm m a mm Wmh M .Mll r. 55 lb. 0 22 CG .F LL
  • This invention relates to a fluorescent display tube and more particularly to a low power type fluorescent tube.
  • a fluorescent tube generally comprises a base of insulator, for example ceramic, having a plurality of recesses on one surface and a plurality of phosphor segments received in the recesses.
  • FlGpl'of the accompanying drawing shows-a typical construction of a prior art fluorescent tube comprising a ceramic base 1 provided with seven recesses which are arranged generally to form a FIG. 8.
  • a phosphor segment 2 is received or embedded as more clearly shown in FIG. 2.
  • Each phosphor segment 2 comprises an anode electrode 2b positioned at the bottom of the recess and provided'vwith a terminal lead 2a extending through the rear surface of the ceramic base 1 and a phosphor 3 covering the surface of anode electrode 2b.
  • a screen grid 4 of metal sheet and provided with a plurality of windows 3 of the number and configuration corresponding to those of phosphor segments 2 is provided to cover the ceramic base. 1.
  • An electron accelerating mesh 5 is provided above the screen grid,4 to cover the entire surface thereof. Accordingly, the electrons emitted from a heaterfi positioned in front of the electron accelerating screen 5 are accelerated and their distribution is made uniform while they pass through electron accelerating mesh 5. Portion of the electrons collide upon the screen grid 4 and are prevented from reaching the ceramic base 1. Remaining portions of the electrons pass through windows 3 to reach phosphor segments 2 to excite phosphors 2c.
  • the percentage of the electrons intercepted by the screen grid 4 is very high so that the value of the screen grid current often amounts to about one-fifth -of the anode current.
  • this grid current constitutes a waste current that does not contribute to the excitation of s the phosphors, it is necessary to decrease as far as possible thiswaste current in order to realize a fluorescent tube of low power. For this reason it has beenproposed to eliminate the screen grid 4, as shown in FIG. 3.
  • the screen grid is removed, the electrons that reach the surface of the ceramic base 1 charge negatively the same.
  • Another object of this invention is to provide an improved fluorescent display tube which is not provided with a screen grid so that it can greatly reduce the waste current but yet increase the brightness of the luminescence of phosphor segments without being affected by the negative charge collected upon the portions of the insulator base about respective phosphor segments.
  • a fluorescent display tube of the type comprising an insulator base having a plurality of recesses on one surface thereof, the recesses being desposed to form selected patterns to be displayed, a phosphor segment and an electrode contained in each recess, and a source of electrons for impinging electrons upon the phosphor segments to cause them to luminesce, characterized in that there is provided a relatively low resistance path directly on the surface of the insulator base for draining electrons impinging upon the surface thereof.
  • the low resistance path takes the form of a mask of metal wire net provided with windows corresponding to the phosphor segments anddirectlyapplied on the surface of the insulator ciently drain to ground. the electrons impinging upon the surface of the insulator base.
  • FIG. 1 is an exploded perspective view of the principal elements of a prior art fluorescent display tube
  • FIG. 2 is an enlarged sectional view of a portion of the fluorescent display tube shown in FIG. 1
  • FIG. 3 is a view similar to FIG. 2 but the screen grid has been removed
  • FIG. 4 is an exploded perspective view of an improved fluorescent display tube embodying the invention
  • FIG. 5 is an enlarged view of a portion of the display tube shown in FIG. 4 and FIG. 6 is a similar view of a modified embodiment of this invention.
  • the fluorescent display tube shown therein comprises a ceramic base 1 having a construction substantially identical to that shown in FIG. 1.
  • Component parts of the display tube corresponding to those shown in FIGS. 1 and 2 are designated by the same reference numerals so it is believed unnecessary to repeat their description.
  • a mask 7 of a fine metal wire mesh is provided directly on the surface of the ceramic base 1. Further, an electron accelerating mesh 5 is disposed at a small distance from the mask 7 to cover the entire surface thereof. It is advantageous to make sufficiently different the mesh sizes of mask 7 and electron accelerating mesh 5 for the purpose of preventing an interference therebetween. As shown by dotted With this improved construction, electrons emitted from heater 6 positioned in front of the electron accelerating mesh are accelerated and their distribution is made uniform while they pass through the electron accelerating mesh 5.
  • the improved fluorescent tube since the mask 7 of a metal wire mesh is mounted directly upon the surface of the ceramic base 1, electrodes colliding upon this surface will be drained to the ground. In other words, the mask 7 provides a low resistance grounding path for the colliding electron, thus efficiently preventing them from negatively charging the surface of the ceramic base 1 thereby ensuring uniform luminescence over the entire areas of respective phosphor segments 2. Further, the improved mask of a metal wire mesh collects much smaller quantity of the waste current than the conventional screen of metal plate. For this reason the efficiency of the fluorescent display tube can be greatly improved and the power consumption can also be decreased greatly.
  • the construction of the fluorescent display tube is much simplified by eliminating the screen of metal sheet shown in FIG. 1 and the mesh of metal wire net shown in FIGS. 4 and 5.
  • the low resistance grounding path for the colliding electrons is provided by using a relatively low resistivity ceramic base 1 having a conductivity of the order of about 3 X10 to 10 ohm-cm.
  • a low resistivity ceramic base can be readily preparing by firing a mixture of a ceramic raw material and a small quantity of an electroconductive material.
  • the resistivity of the ceramic base I is much higher than that of metal or ordinary conductor so that it is possible to maintain the potential impressed upon respective phosphors 2c or anode electrodes but the electrons impinging upon the surface of the ceramic base can efficiently be drained to the ground through the ceramic body.
  • a fluorescent display tube of the type comprising a insulator base having a plurality of recesses on one surface thereof, said recesses being disposed to form selected patterns to be displayed, a phosphor segment and an electrode contained in each of said recesses, and a source of electrons for impinging electrons upon said phosphor segments to cause them to luminesce, the improvement which comprises a relatively low resistance path provided directly on the surface of said insulator base for draining said electrons imaging upon the surface thereof.

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  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
US183054A 1970-09-25 1971-09-23 Fluorescent display tubes Expired - Lifetime US3705324A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP9483570U JPS4914286Y1 (OSRAM) 1970-09-25 1970-09-25
JP9483470U JPS4914285Y1 (OSRAM) 1970-09-25 1970-09-25

Publications (1)

Publication Number Publication Date
US3705324A true US3705324A (en) 1972-12-05

Family

ID=26436077

Family Applications (1)

Application Number Title Priority Date Filing Date
US183054A Expired - Lifetime US3705324A (en) 1970-09-25 1971-09-23 Fluorescent display tubes

Country Status (4)

Country Link
US (1) US3705324A (OSRAM)
DE (1) DE2147797B2 (OSRAM)
FR (1) FR2108526A5 (OSRAM)
GB (1) GB1321956A (OSRAM)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3836806A (en) * 1972-09-20 1974-09-17 Nippon Electric Kagoshima Ltd Luminescence display tube base plate comprising protrusions extended sideways beyond grid supports
US4047072A (en) * 1975-03-28 1977-09-06 Futaba Denshi Kogyo Kabushiki Kaisha Multi-digit fluorescent display tube
EP1709708A1 (en) * 2004-01-29 2006-10-11 Anders Thulin Consulting AB A device for dissipating static electricity

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4337411A (en) * 1980-04-10 1982-06-29 Mcgraw-Edison Company Application of insulation to ride frame of vacuum fluorescent display

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3836806A (en) * 1972-09-20 1974-09-17 Nippon Electric Kagoshima Ltd Luminescence display tube base plate comprising protrusions extended sideways beyond grid supports
US4047072A (en) * 1975-03-28 1977-09-06 Futaba Denshi Kogyo Kabushiki Kaisha Multi-digit fluorescent display tube
EP1709708A1 (en) * 2004-01-29 2006-10-11 Anders Thulin Consulting AB A device for dissipating static electricity
US20080055812A1 (en) * 2004-01-29 2008-03-06 Anders Thulin Consulting Ab Device for Dissipating Static Electricity
US7573696B2 (en) * 2004-01-29 2009-08-11 Anders Thulin Consulting Ab Device for dissipating static electricity

Also Published As

Publication number Publication date
DE2147797A1 (de) 1972-03-30
DE2147797B2 (de) 1975-10-02
FR2108526A5 (OSRAM) 1972-05-19
GB1321956A (en) 1973-07-04

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