EP0383672A1 - Flache Beleuchtungseinheit - Google Patents

Flache Beleuchtungseinheit Download PDF

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Publication number
EP0383672A1
EP0383672A1 EP19900400385 EP90400385A EP0383672A1 EP 0383672 A1 EP0383672 A1 EP 0383672A1 EP 19900400385 EP19900400385 EP 19900400385 EP 90400385 A EP90400385 A EP 90400385A EP 0383672 A1 EP0383672 A1 EP 0383672A1
Authority
EP
European Patent Office
Prior art keywords
source
electrode
electrodes
wall
electrons
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.)
Granted
Application number
EP19900400385
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English (en)
French (fr)
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EP0383672B1 (de
Inventor
Jean-Frédéric Clerc
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.)
Commissariat a lEnergie Atomique et aux Energies Alternatives CEA
Original Assignee
Commissariat a lEnergie Atomique CEA
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Publication of EP0383672A1 publication Critical patent/EP0383672A1/de
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Anticipated expiration legal-status Critical
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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J63/00—Cathode-ray or electron-stream lamps
    • H01J63/06—Lamps with luminescent screen excited by the ray or stream

Definitions

  • the present invention relates to a planar light source and relates more generally to the production of wide planar sources of small thickness as used for the rear lighting of display devices (liquid crystal screen), the rear lighting of photographic films, etc.
  • the first technique consists in using fluorescent sources and in particular such sources in the form of tubes which are juxtaposed one beside the other in more or less number.
  • fluorescent tubes such as discharge tubes are used which are juxtaposed side by side, which leads to illuminating surfaces whose uniformity of lighting is imperfect and whose thickness is at a minimum. of the order of 1 cm, taking into account the minimum dimensions of commercially available fluorescent tubes.
  • the second technique consists in using sources of the electroluminescent type. Unlike fluorescent sources, there are electroluminescent sources consisting of plates but these devices have a very poor performance and the heat they give off to obtain a certain intensity of lighting is quite significant. Furthermore, the life of such devices is limited. The two previous drawbacks have considerably limited the use of electroluminescent sources apart from very specific applications such as night use.
  • the subject of the present invention is a flat light source, which is easy to produce using simple means and which leads to a device of small thickness (approximately 2 mm) with high gloss (several thousand candela per square meter). with very good uniformity of lighting and a very long service life.
  • the planar light source object of the invention, is characterized in that it comprises: - a vacuum enclosure limited by a side wall and two parallel and insulating flat walls, - on each preceding flat wall, and inside the enclosure, a conductive electrode covered with an insulating layer, at least one of these two wall-electrode-insulating layer assemblies being transparent, - on one of the insulating layers, a layer of cathodoluminescent material, - in the vicinity of the side wall and externally to the two conductive electrodes, a source of electrons, a voltage source making it possible to apply alternately to the two conductive electrodes two distinct potentials (V anode , V rest ) such that the electrons emitted by said electron source are alternately collected by said electrodes.
  • the planar light source which is the subject of the invention uses the cathodoluminescence effect already employed for example in the cathode ray tubes of our television sets.
  • a material is said to be cathodoluminescent when under the effect of a bombardment by electrons of a certain kinetic energy, it emits radiation luminous.
  • Such known cathodoluminescent bodies are often wrongly called "phosphors".
  • a conventional cathodoluminescent material covers the internal face of one of the armatures of a planar capacitor, the corresponding electrode consisting of a conductive material covered with a layer of electrical insulator, such as the electrode of the opposite armature of the planar capacitor, moreover.
  • the source object of the invention When the source object of the invention is made to light from only one of its flat walls, at least the corresponding wall as well as the electrode and the insulating material placed on this wall must be transparent, in other words capable of allowing passage the light emitted by cathodoluminescence.
  • this source When this source is made to light from its two flat walls, these as well as the electrodes and the corresponding insulating materials must be transparent.
  • a source of electrons of a type known per se which allows, after putting under high tension of the armature chosen as anode, to charge the preceding plane capacitor by depositing electrons which will localize in the form of a cloud of negative electricity in the vicinity of this anode, the insulating material deposited on the electrode preventing these same negative electric charges from flow through the anode.
  • the electrons When the charge of the capacitor is thus achieved, if the electrons are made to oscillate by a voltage source applying alternately to the two conductive electrodes two distinct potentials such that the electrons are alternately collected by these electrodes, the electrons then oscillate at the frequency of the signal applied between the reinforcements in the zone which separates them thus causing an excitation of the cathodoluminescent material which they come to strike at each period by causing an emission of light.
  • the electron source located in the vacuum enclosure practically no longer delivers current, except to compensate at all times for the leakage of electrons by electrical faults in the insulators, keeping these at a constant number.
  • the usable electron source can be either a hot source (heated filament) or a cold source (photoemission, field effect).
  • the number of electrons in oscillation in the light source corresponds to the capacity of the planar capacitor thus produced and is therefore entirely determined by the dimensions of the capacitor, the thickness of the insulators and the voltage applied to the armatures. In particular, it does not depend on the emission characteristics of the auxiliary electron source used. In other words, during permanent operation, the light sensation felt by an observer of the source therefore only depends on the frequency of oscillation because the quantity of light emitted in each period is constant. This guarantees the uniformity of the illumination produced by cathodoluminescence.
  • planar light source which is the subject of the invention lies in the fact that its structure is perfectly compatible with the manufacture of planar sources of thin thickness (up to 2 mm) and of very large surface (several square decimetres per example without difficulty).
  • the plane light source which is the subject of the invention can emit with a very high brightness which is adjustable both by the voltage imposed on the armatures and the frequency of the source, two parameters which influence this same brightness approximately linearly.
  • FIG. 1 there is shown in a vacuum enclosure 1 limited by a side wall 2 and two flat, parallel and transparent walls of glass for example, respectively upper 3 and lower 4, the elements of a planar light source conforming to the invention and which comprises: a transparent conductive electrode 5 situated inside the enclosure 1 on the wall 3; a conductive electrode 6 inside the enclosure 1 on the wall 4; two layers of insulating material 7 and 8 respectively covering the conductive electrodes 5 and 6 and on one of the armatures, here the lower armature, a layer of cathodoluminescent material 9.
  • a voltage generator 10 makes it possible to control the potential of the electrodes 5 and 6.
  • the device is supplemented by the electron source 11, for example of the heating filament type at the terminals of which the voltages V 1s and V 2s are applied.
  • the side walls 3 and 4 are produced by glass plates sealingly sealed on the side wall 2.
  • the upper glass substrate 3 is covered with the transparent conductor 5, consisting of indium oxide doped with tin, with a thickness of approximately 1000 Angstroms and the insulating layer 7 which covers the preceding conductor 5 is a layer of silica. about 5 micrometers.
  • the lower glass substrate 4 is covered with a metallic conductor 6.
  • this conductor 6 can be produced by an aluminum deposit with a thickness of approximately 1000 Angstroms.
  • a thin insulating layer 8 produced, like the homologous layer 7, by a deposit of silica about 5 micrometers thick.
  • a layer 9 of cathodoluminescent material produced either by screen printing from a powder, or directly by deposition in a thin layer, with a thickness of the order of 1 micrometer.
  • cathodoluminescent bodies which can be used in the context of the invention and they may for example have recourse to oxysulfide Y2O2S doped with europium to obtain a light emission in red, or to zinc sulfide ZnS doped with copper and aluminum for a light emission in green, and zinc sulfide ZnS doped with silver for a light emission in blue.
  • the electron emitting source 11 can be produced from any known means, such as for example the heated filaments emitting by thermoelectric effect, the conductive microtips emitting by field effect and the thin layers emitting by photoemissive effect .
  • the electron source 11 consists of a photoemissive layer, only one connection with the outside is necessary.
  • the person skilled in the art will in any case be able to use the electron source 11 to obtain, after having chosen one of the two conductors 5 or 6 as the anode, the charge of the plane capacitor formed by these two same conductors 5 and 6.
  • one of the wall assemblies 3 - conductive electrode 5 - insulating layer 7 alone is transparent and the source emits only on one side. It would also be possible, without departing from the scope of the invention, to produce a planar source emitting on the two faces by manufacturing the two walls 3 and 4, the two electrodes 5 and 6 and the two insulating layers 7 and 8 in transparent materials.
  • planar light source comprises two stages, namely: - firstly a step which will be called a static regime and during which the voltage source 10 carries the electrodes 5 and 6 to constant potentials and the electron source 11 is used to charge the capacitor formed by the two electrodes conductors 5 and 6 above. During this static loading, the source emits no light radiation.
  • This static regime will be described with reference to Figures 2 (2a, 2b, 2c).
  • a second regime termed dynamic, which in fact corresponds to the periods of operation of the light emission source and will be described next with reference to FIG. 3.
  • the voltage source 10 delivers constant potentials V sup and V inf .
  • the FIG. 2b shows the variation 12 of the density of these same electrons in the vicinity of the upper wall 3.
  • the electrons thus collected by the upper conductor 5 are not eliminated by the latter since the insulating layer 7 prevents them from s '' flow directly into the condenser circuit. These same electrons therefore accumulate at the interface between the vacuum of the enclosure 1 and the insulating layer 7, until the local potential reaches the same value as the potential of the emissive source.
  • the potential in the vicinity of the insulation layer is approximately that which is applied between the emissive electron source 11 and the upper conductor 5 acting as an anode. This potential is therefore, in the example chosen, of the order of 1 kilovolt, which justifies the thicknesses of 5 micrometers chosen for the insulating layers 7 and 8.
  • the number of electrons collected by the upper anode conductor 5 to the state of equilibrium is proportional both to the difference in potential between the source 11 and the collecting electrode 5 and, conversely, to the thickness of the insulator 7, as is the capacity of the capacitor thus formed.
  • FIG. 2a The right part of FIG. 2a as well as FIG. 2c illustrate the symmetrical choice in which the user would have put the upper electrode 5 at rest and would have chosen to bring the lower electrode 6 to a potential of 1 kilovolt to make it the 'anode electrode.
  • This mode of implementation which is rigorously symmetrical to the previous one and will be deduced therefrom without difficulty for those skilled in the art, will not be described any further.
  • the dynamic regime of the source will be described, that is to say the regime during which, after the previous static charge phase, the potentials of the conducting electrodes 5 and 6 are periodically reversed. to obtain, by impact on the cathodoluminescent layer 9 of negative electrical charges, the effect of light emission.

Landscapes

  • Discharge Lamps And Accessories Thereof (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Electroluminescent Light Sources (AREA)
EP90400385A 1989-02-15 1990-02-13 Flache Beleuchtungseinheit Expired - Lifetime EP0383672B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8901960A FR2643191B1 (fr) 1989-02-15 1989-02-15 Source lumineuse plane
FR8901960 1989-02-15

Publications (2)

Publication Number Publication Date
EP0383672A1 true EP0383672A1 (de) 1990-08-22
EP0383672B1 EP0383672B1 (de) 1994-01-12

Family

ID=9378809

Family Applications (1)

Application Number Title Priority Date Filing Date
EP90400385A Expired - Lifetime EP0383672B1 (de) 1989-02-15 1990-02-13 Flache Beleuchtungseinheit

Country Status (5)

Country Link
US (1) US5045754A (de)
EP (1) EP0383672B1 (de)
JP (1) JP2799436B2 (de)
DE (1) DE69005844T2 (de)
FR (1) FR2643191B1 (de)

Families Citing this family (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5543691A (en) * 1995-05-11 1996-08-06 Raytheon Company Field emission display with focus grid and method of operating same
US6252347B1 (en) 1996-01-16 2001-06-26 Raytheon Company Field emission display with suspended focusing conductive sheet
US5982092A (en) * 1997-10-06 1999-11-09 Chen; Hsing Light Emitting Diode planar light source with blue light or ultraviolet ray-emitting luminescent crystal with optional UV filter
US20040145381A1 (en) * 2001-12-28 2004-07-29 Jun Su Test fixture for die-level testing of planar lightwave circuits
JP4631716B2 (ja) * 2006-01-18 2011-02-16 パナソニック電工株式会社 放電プラズマ生成補助装置
JP4618145B2 (ja) * 2006-01-31 2011-01-26 パナソニック電工株式会社 放電プラズマ装置
JP4944503B2 (ja) * 2006-06-09 2012-06-06 パナソニック株式会社 放電点灯装置およびそれを用いた照明器具
JP4944502B2 (ja) * 2006-06-09 2012-06-06 パナソニック株式会社 放電点灯装置および照明器具。
DE202007005027U1 (de) * 2007-04-03 2008-08-07 Gies, Johannes Energiespar-Flachleuchte
US9242019B2 (en) 2014-03-13 2016-01-26 Stellarray, Incorporated UV pipe
US11253996B1 (en) 2021-06-30 2022-02-22 Toyota Motor Engineering & Manufacturing North America, Inc. Artificial muscles having vacuum coupled electrode insulators and methods of manufacturing the same

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2437661A1 (fr) * 1978-09-27 1980-04-25 Smiths Industries Ltd Dispositif d'affichage par luminescence cathodique
FR2438337A1 (fr) * 1978-10-05 1980-04-30 Brady Co W H Procede et dispositif de production de lumiere ultraviolette

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4928185A (de) * 1972-07-13 1974-03-13
US4126384A (en) * 1976-08-13 1978-11-21 Rca Corporation Self-illuminated liquid crystal display device
US4274028A (en) * 1978-10-05 1981-06-16 W. H. Brady Company Ultraviolet light generation
US4429303A (en) * 1980-12-22 1984-01-31 International Business Machines Corporation Color plasma display device
JPS5810481U (ja) * 1981-07-10 1983-01-22 シャープ株式会社 液晶表示装置
JPS61107653A (ja) * 1984-10-31 1986-05-26 Futaba Corp 光源用真空螢光管とその製造方法
US4772885A (en) * 1984-11-22 1988-09-20 Ricoh Company, Ltd. Liquid crystal color display device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2437661A1 (fr) * 1978-09-27 1980-04-25 Smiths Industries Ltd Dispositif d'affichage par luminescence cathodique
FR2438337A1 (fr) * 1978-10-05 1980-04-30 Brady Co W H Procede et dispositif de production de lumiere ultraviolette

Also Published As

Publication number Publication date
EP0383672B1 (de) 1994-01-12
JP2799436B2 (ja) 1998-09-17
FR2643191A1 (fr) 1990-08-17
DE69005844T2 (de) 1994-07-14
FR2643191B1 (fr) 1991-05-10
US5045754A (en) 1991-09-03
DE69005844D1 (de) 1994-02-24
JPH02242561A (ja) 1990-09-26

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