WO2000025338A1 - Structure de cathode pour tube cathodique - Google Patents
Structure de cathode pour tube cathodique Download PDFInfo
- Publication number
- WO2000025338A1 WO2000025338A1 PCT/JP1999/005887 JP9905887W WO0025338A1 WO 2000025338 A1 WO2000025338 A1 WO 2000025338A1 JP 9905887 W JP9905887 W JP 9905887W WO 0025338 A1 WO0025338 A1 WO 0025338A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- electron
- substrate
- cathode
- emitting material
- material layer
- Prior art date
Links
Classifications
-
- 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
- H01J29/04—Cathodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/13—Solid thermionic cathodes
- H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2201/00—Electrodes common to discharge tubes
- H01J2201/19—Thermionic cathodes
- H01J2201/193—Thin film cathodes
Definitions
- the present invention relates to a cathode structure provided in an electron gun of a cathode ray tube used for a television / computer monitor or the like.
- the cathode ray tube 1 has a face plate portion 3 having a fluorescent screen 2 on the inner surface, a funnel portion 4 adhered behind the face plate portion 3, and a neck portion 7 of the funnel portion 4. And an electron gun 6 for emitting an electron beam 5 disposed therein.
- cathode structure 1 0 8 indirectly heated are provided, the cathode structure 1 0 8, the cap on one end of the tubular sleeve 1 0 9
- the substrate 110 is covered with an electron-emitting material layer 111 composed of an electron-emitting emitter that emits thermoelectrons on the surface of the substrate 110.
- a coil-shaped heating heater 115 having an alumina insulating layer 113 on the metal wire coil 112 and a dark layer 114 on the upper layer is provided. Have been.
- the electron-emitting material layer 111 is formed on the entire substrate surface 120 facing the electron-emitting side.
- the reducing element for example, magnesium, silicon, etc.
- the reducing element contained in the substrate is converted into an interface between the electron-emitting substance and the substrate. It diffuses heat to the surface, reduces electron-emitting materials (mainly alkaline earth oxides such as barium oxide), and generates free barium to enable electron emission.
- This reduction reaction is represented by the following equation.
- the above-mentioned conventional cathode assembly has a problem that sufficient electron emission cannot be obtained in the initial activation step, and a problem that electron emission during operation greatly decreases with time.
- the shrinkage of the electron-emitting material layer during operation due to the progress of the reduction reaction becomes excessive, and the fluctuation of the cut-off voltage (electron beam erasing voltage), which is inversely proportional to the distance between the counter electrode and the electron-emitting material, increases.
- the amount of the electron-emitting substance and the size of the substrate are set so as to satisfy a predetermined relationship. It has been found that if adjusted, the above-described reduction reaction proceeds appropriately and the above-mentioned problem can be solved.
- An object of the present invention is to provide a cathode assembly having improved characteristics by optimizing the relationship between the size of the substrate and the size of the electron-emitting material layer.
- One embodiment of the cathode assembly of the present invention is a cathode assembly for a cathode ray tube in which an electron emitting material layer is formed on a substrate containing a reducing element, wherein the area of the layer forming surface of the substrate is A, and When the contact area with the electron emitting material layer is B, 0.24 ⁇ BZA ⁇ 0.93.
- the layer forming surface of the substrate refers to the surface facing the electron emission side of the substrate, and does not correspond to the side surface of the substrate.
- the area of this surface can be obtained by ⁇ (d / 2) 2 based on its diameter d if the layer forming surface is circular.
- cathode structure of the present invention is a cathode in which an electron-emitting material layer is formed on a substrate containing a reducing element, wherein the thickness of the substrate is C, and the thickness of the electron-emitting material layer is C. It is characterized by satisfying the relationship of 0.4 ⁇ DZC ⁇ 0.7 when D is D.
- the cathode structure satisfies both of the above relationships (0.24 ⁇ B / A ⁇ 0.93, 0.4 ⁇ D / C ⁇ 0.7), it has a long life and small fluctuations in cutoff voltage. it can.
- FIG. 1 is a cross-sectional view of one embodiment of the cathode structure of the present invention.
- FIG. 2 is a sectional view showing an example of a cathode ray tube.
- FIG. 3 is a diagram showing the relationship between the G1 voltage and the cathode current during the accelerated life test.
- FIG. 4 is a diagram showing the relationship between the ratio BZ A and the zero field saturation current density.
- FIG. 5 is a schematic partial cross-sectional view of the cathode structure for explaining a chemical reaction occurring between the substrate and the electron-emitting material layer.
- FIG. 6 is a diagram showing the relationship between the ratio DZC and zero field saturation current density.
- FIG. 7 is a diagram showing the relationship between the ratio D / C and the cut-off voltage reduction rate.
- FIG. 8 is a cross-sectional view of one embodiment of a conventional cathode structure.
- a cap-shaped base 10 is welded to the sleeve 9 so as to cover one end of the cylindrical sleeve 9.
- an electron emitting material layer 11 composed of an electron emitting emitter emitting thermoelectrons is formed.
- a coil-shaped heating heater 15 having an alumina insulating layer 13 on a metal wire coil 12 and a dark layer 14 on the alumina insulating layer 13 is provided.
- the base 10 is mainly composed of nickel and contains reducing elements such as magnesium and silicon. Tungsten, aluminum, or the like may be used as the reducing element.
- the ratio BZA is in the range of 0.24 to 0.93.
- the thickness of the substrate 10 is (:, and the thickness of the electron-emitting material layer 11 is D
- the ratio D / C is in the range of 0.4 or more and 0.7 or less. Is the area of the upper surface 20 facing the electron emission side, excluding the side surface 21 of the base 10.
- the zero field saturation current density becomes 6.4 (A / cm 2) after 500 hours of the accelerated life test. )
- the cutoff voltage is within 85% of the initial value, which is a sufficiently good performance in normal operation.
- a powder mainly composed of alkaline earth metal carbonate is dissolved in an organic solvent consisting of 85% [%] of diethyl carbonate and 15% [%] of nitric acid to prepare a mixed coating solution (resin solution).
- the powder contains at least barium carbonate, strontium and It shall contain at least one of calcium.
- the content ratio of barium carbonate to strontium carbonate is preferably 1: 1 by weight.
- this mixed coating solution is sprayed and applied to the surface 20 of the substrate 10.
- a frame (not shown) having an opening corresponding to a predetermined electron-emitting material coating portion on the base 10 and spraying, the electron-emitting material layer 11 can be formed only on a predetermined portion.
- the thickness of the electron emitting material layer 11 can be controlled by adjusting the spray time.
- the thickness of the electron-emitting material layer 11 is measured, for example, by pressing a metal plate from above the electron-emitting material layer 11 and measuring the total thickness of the substrate 10 and the electron-emitting material layer 11. It can be measured by subtracting the thickness of the substrate 10 from the value.
- An appropriate weight of the metal plate is about 20 [g].
- decomposition of carbonate to oxide and activation to reduce a part of oxide are performed according to a conventional method in a conventional cathode structure.
- the cathode shown in Fig. 1 was fabricated by changing the size of the base (circular top surface) and the area or thickness of the electron emitting material layer (also circular) sprayed thereon.
- the cathode In order to confirm the relationship between the surface area A of the substrate and the area B of the electron-emitting substance layer as the cathode, three types of substrates with a layer forming surface diameter of 0.1, 0.2, and 0.3 (mm) were used. For each, a cathode having five types of electron emitting material layers formed so that the ratio BZA was 1.0, 0.88, 0.62, 0.24, and 0.1 was prepared. The thickness of the substrate was constant at 100 [m], and the thickness of the electron emitting material layer was constant at 65 iiim).
- the thickness of the three types of substrates with a thickness of 0.1, 0.15, and 0.2 mm was confirmed.
- three types of electron emitting material layers having ratios D / C of 0.32, 0.65, and 0.937, that is, a total of nine types of cathodes were prepared.
- the diameter of the layer forming surface of the substrate was constant at 0.2 [mm]
- the diameter of the electron emitting material layer was constant at 1.6 [mm].
- a life test was performed using the dummy tube thus manufactured.
- the conditions of the life test were as follows: the cathode temperature was 820 [° C] and the cathode extraction current was DC 300 [A]. The test performed under these conditions is equivalent to the accelerated life test for normal operation (760 C ° C).
- the effect of the ratio BZA between the substrate surface area A and the electron emitting material layer area B on the electron emission characteristics was investigated.
- the electron emission capability was evaluated by using the electric field saturation current density of the cell and the power source cutoff voltage. These values are described below.
- Figure 3 shows the relationship between the pulse voltage applied to the G1 electrode and the cathode current (electron emission), and shows the measurement results at a life of 5000 hours during the life test as an example.
- the G1 electrode is an electrode facing the cathode of the pole portion, and in this case, is an extraction electrode for extracting electrons from the cathode.
- the curve a in Fig. 3 is obtained by measuring the cathode current flowing when a positive pulse voltage is applied to the electrode G1, and plotting the logarithm of the cathode current against the square root of the applied voltage (Schottky plot). Curve.
- the cathode current sharply increases with the increase in the G1 voltage, and in the region where the G1 voltage is sufficiently high, it saturates and becomes a straight line. This linear part is reduced to G1 voltage 0.
- the current value J at G 1 voltage 0 of the line b extrapolated by Is called the zero field saturation emission.
- Zero field saturation emission indicates the intrinsic electron emission capability of the cathode excluding the effects of the electric field.
- This zero field saturation emission J The value obtained by dividing by the surface area of the electron emitting material layer is defined as zero field saturation current density. The higher the zero field saturation current density, the better the cathode has the ability to emit electrons.
- the power source cutoff voltage is the G1 voltage at which the cathode current becomes zero when a voltage is applied to the power source and driven in triode operation.
- Curve a in FIG. 4 shows the case where the diameter of the substrate is 0.3 [mm]
- curve b shows 0.2 [mm]
- curve c shows the case where the diameter is 0.3 [mm]. From Fig. 4, it is practically sufficient if the ratio BZA is in the range of 0.24 or more and 0.93 or less, regardless of the diameter of any substrate, that is, zero field saturation current density of 6.4 [A / cm 2 ] or more. Can be obtained.
- FIG. 5 schematically shows a phenomenon occurring inside the substrate 10 and the electron-emitting material layer 11.
- the reducing elements magnesium, silicon, etc.
- the reducing element 51 a in the portion in contact with the electron emitting material layer 11 is consumed to reduce the electron emitting material in the electron emitting material layer 11.
- the reduced electron-emitting material becomes free barium, generating emitted electrons 52.
- Let 5 lb of the reducing element present in the portion where the electron emitting material layer 11 is not in contact diffuses according to the concentration gradient of the reducing element in the substrate 10, and the portion where the electron emitting material layer 11 is in contact To reach. Then, the action of reducing the electron emitting material layer 11 is increased. This series of processes is considered to proceed properly when the area ratio BZA at the cathode is within the numerical range of 0.24 to 0.93.
- the ratio BZA is 0.88 or less, the zero field saturation current density is further improved to 6.65 [A / cm 2] . Further, when the ratio BZA is 0.62 or less, the amount of the electron-emitting substance can be significantly reduced, which is more preferable from the viewpoint of cost reduction.
- the ratio B / A is 0.35 or more, no equipment change is required at the time of production, and peeling of the emitter can be suppressed, thus further improving the quality. It is particularly preferable to set the ratio BZ A to 0.40 or more, since the life up to the end of life (cutoff fluctuation: 10%, emission reduction rate: 30%) can be extended.
- the ratio D / C of the thickness C of the substrate to the thickness D of the electron emitting material layer is determined by the electron The effects on radiation characteristics were investigated.
- Figure 6 shows the relationship between the ratio DZC and the zero field saturation current density after 50,000 hours of life test (500 hours of life).
- Curve a in FIG. 6 shows the case where the thickness of the substrate is 0.1 [mm]
- curve b shows the case where the thickness is 0.15 [mm]
- curve c shows the case where the thickness of the substrate is 0.2 [mm].
- D / C when the D / C is 0.4 or more, a zero field saturation current density of 6.4 (A / cm 2 ] or more can be obtained at a life of 5000 hours. Is proportional to the ratio between the valley of the electron-emitting material layer and the number of reducing elements, so if the ratio DZC is too small, the reduction reaction decreases and the electron emission decreases.
- FIG. 7 also shows the relationship between the ratio D / C and the rate of decrease in cutoff voltage at a life of 500 hours.
- Curve a in FIG. 7 shows the case where the thickness of the substrate is 0.1 [mm]
- curve b shows the case where the thickness is 0.15 [mm]
- curve c shows the case where the thickness of the substrate is 0.2 [mm].
- the cut-off voltage can be kept within 115%, that is, a value of 85% or more of the initial value.
- the electron-emitting layer shrinks in proportion to its thickness due to a reduction reaction during operation.
- the ratio DZC increases, the thickness of the electron emitting material layer becomes relatively large, so that the shrinkage during operation increases, and the fluctuation of the cutoff voltage increases. Therefore, in order to suppress a decrease in the electron emission ability, it is preferable that DZC is equal to or less than a predetermined value.
- the ratio DZC is preferably 0.4 or more and 0.7 or less.
- the present invention it is possible to provide an electron-emitting material layer having an optimal size corresponding to substrates having various sizes, and to realize a zero electric current for each cathode. It is possible to provide a long-life cathode structure with a small variation in field saturation current density and a small change in cut-off voltage. In addition, if the size of the base is determined, the size of the electron emitting material layer required for practical operation can be easily determined, so that the cathode structure can be designed easily and quickly. As described above, the present invention has great industrial value in the technical field of cathode ray tubes.
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP99949406A EP1126493B1 (en) | 1998-10-28 | 1999-10-25 | Cathode structure for cathode ray tube |
US09/830,444 US6492765B1 (en) | 1998-10-28 | 1999-10-25 | Cathode structure for cathode ray tube |
DE69938053T DE69938053T2 (de) | 1998-10-28 | 1999-10-25 | Kathodenstruktur für eine kathodenstrahlröhre |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP30659098 | 1998-10-28 | ||
JP10/306590 | 1998-10-28 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2000025338A1 true WO2000025338A1 (fr) | 2000-05-04 |
Family
ID=17958906
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1999/005887 WO2000025338A1 (fr) | 1998-10-28 | 1999-10-25 | Structure de cathode pour tube cathodique |
Country Status (7)
Country | Link |
---|---|
US (1) | US6492765B1 (ja) |
EP (1) | EP1126493B1 (ja) |
KR (1) | KR100400587B1 (ja) |
CN (1) | CN1159745C (ja) |
DE (1) | DE69938053T2 (ja) |
TW (1) | TW430842B (ja) |
WO (1) | WO2000025338A1 (ja) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB0131097D0 (en) | 2001-12-31 | 2002-02-13 | Applied Materials Inc | Ion sources |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60165021A (ja) * | 1984-02-08 | 1985-08-28 | Hitachi Ltd | 陰極線管 |
JPH05174701A (ja) * | 1991-12-24 | 1993-07-13 | Hitachi Ltd | 陰極構体 |
JPH0744048U (ja) * | 1990-08-30 | 1995-10-24 | エルジー電子株式会社 | 電子管用陰極構造体 |
Family Cites Families (18)
Publication number | Priority date | Publication date | Assignee | Title |
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JPS5936379B2 (ja) * | 1976-01-14 | 1984-09-03 | 株式会社東芝 | 陰極構体 |
JPS52122456A (en) * | 1976-04-07 | 1977-10-14 | Toshiba Corp | Indirectly heat type cathode |
NL8304401A (nl) * | 1983-12-22 | 1985-07-16 | Philips Nv | Oxydkathode. |
KR930007588B1 (ko) * | 1986-09-29 | 1993-08-13 | 주식회사 금성사 | 음극선관의 방열형 캐소드 구조체 |
KR920001337B1 (ko) * | 1989-09-07 | 1992-02-10 | 삼성전관 주식회사 | 전자관음극 및 그 제조방법 |
NL9002291A (nl) * | 1990-10-22 | 1992-05-18 | Philips Nv | Oxydekathode. |
KR940006919Y1 (ko) * | 1991-12-03 | 1994-10-06 | 주식회사 금성사 | 전자관용 방열형 음극 구조체 |
KR930014719A (ko) * | 1991-12-13 | 1993-07-23 | 이헌조 | 브라운관용 전자총 |
JPH05334954A (ja) | 1992-05-29 | 1993-12-17 | Nec Kansai Ltd | 陰極構体およびその製造方法 |
JP3181119B2 (ja) | 1992-11-18 | 2001-07-03 | キヤノン株式会社 | 防振装置 |
KR970009208B1 (en) * | 1993-07-26 | 1997-06-07 | Lg Electronics Inc | Cathode structure of electron gun for crt |
JPH0744048A (ja) | 1993-07-29 | 1995-02-14 | Toray Ind Inc | 複写機用熱定着ローラーの駆動歯車 |
JPH0778549A (ja) * | 1993-09-10 | 1995-03-20 | Hitachi Ltd | 陰極線管 |
KR970007196U (ko) * | 1995-07-31 | 1997-02-21 | 음극선관의 전자총용 함침형 음극구조체 | |
JPH09102266A (ja) * | 1995-10-03 | 1997-04-15 | Matsushita Electron Corp | 傍熱型陰極およびこれを用いた陰極線管 |
JPH10125214A (ja) * | 1996-10-24 | 1998-05-15 | Hitachi Ltd | 酸化物陰極 |
TW388048B (en) * | 1997-04-30 | 2000-04-21 | Hitachi Ltd | Cathode-ray tube and electron gun thereof |
KR100244175B1 (ko) * | 1997-11-13 | 2000-02-01 | 구자홍 | 전자관용 음극 |
-
1999
- 1999-10-21 TW TW088118201A patent/TW430842B/zh not_active IP Right Cessation
- 1999-10-25 KR KR10-2001-7005388A patent/KR100400587B1/ko not_active IP Right Cessation
- 1999-10-25 US US09/830,444 patent/US6492765B1/en not_active Expired - Fee Related
- 1999-10-25 DE DE69938053T patent/DE69938053T2/de not_active Expired - Fee Related
- 1999-10-25 WO PCT/JP1999/005887 patent/WO2000025338A1/ja active IP Right Grant
- 1999-10-25 CN CNB998152196A patent/CN1159745C/zh not_active Expired - Fee Related
- 1999-10-25 EP EP99949406A patent/EP1126493B1/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS60165021A (ja) * | 1984-02-08 | 1985-08-28 | Hitachi Ltd | 陰極線管 |
JPH0744048U (ja) * | 1990-08-30 | 1995-10-24 | エルジー電子株式会社 | 電子管用陰極構造体 |
JPH05174701A (ja) * | 1991-12-24 | 1993-07-13 | Hitachi Ltd | 陰極構体 |
Non-Patent Citations (1)
Title |
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See also references of EP1126493A4 * |
Also Published As
Publication number | Publication date |
---|---|
CN1332886A (zh) | 2002-01-23 |
US6492765B1 (en) | 2002-12-10 |
DE69938053T2 (de) | 2009-01-15 |
EP1126493A4 (en) | 2004-03-10 |
DE69938053D1 (de) | 2008-03-13 |
TW430842B (en) | 2001-04-21 |
EP1126493B1 (en) | 2008-01-23 |
KR20010089378A (ko) | 2001-10-06 |
CN1159745C (zh) | 2004-07-28 |
KR100400587B1 (ko) | 2003-10-08 |
EP1126493A1 (en) | 2001-08-22 |
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