GB2239148A - Dynamic focus voltage generator - Google Patents
Dynamic focus voltage generator Download PDFInfo
- Publication number
- GB2239148A GB2239148A GB9027094A GB9027094A GB2239148A GB 2239148 A GB2239148 A GB 2239148A GB 9027094 A GB9027094 A GB 9027094A GB 9027094 A GB9027094 A GB 9027094A GB 2239148 A GB2239148 A GB 2239148A
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- GB
- United Kingdom
- Prior art keywords
- focus
- voltage
- voltage generator
- dynamic
- direct
- 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.)
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
- H04N3/16—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by deflecting electron beam in cathode-ray tube, e.g. scanning corrections
- H04N3/26—Modifications of scanning arrangements to improve focusing
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N3/00—Scanning details of television systems; Combination thereof with generation of supply voltages
- H04N3/10—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical
- H04N3/16—Scanning details of television systems; Combination thereof with generation of supply voltages by means not exclusively optical-mechanical by deflecting electron beam in cathode-ray tube, e.g. scanning corrections
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- Engineering & Computer Science (AREA)
- Multimedia (AREA)
- Signal Processing (AREA)
- Details Of Television Scanning (AREA)
Abstract
A focus-voltage generator for the focusing electrode of a cathode ray tube is disclosed, which seeks to provide improved focusing, especially away from the centre of the picture. It comprises a direct-current focus-voltage generator 100, 200 for generating a direct-current focus voltage and a dynamic focus-voltage generator for generating direct-current focus voltages for a horizontal and a vertical period. The dynamic focus-voltage generator includes a horizontal focus- voltage generator 300 and a vertical focus-voltage generator 400 and a modulator 500, 600 for modulating the output from the horizontal focus-voltage generator 300 with the vertical period. Alternative embodiments are disclosed (Figs 4 and 5). The Fig 5 embodiment uses an inductance coupled to a D.C. source to modulate the horizontal dynamic focus-voltage waveform. <IMAGE>
Description
4 1 :2::z- 3 S, J_.4 a FOCUS-VOLTAGE GENERATOR FOR A CATHODE RAY TUBE 1
This invention relates to a generator of a focus voltage for a cathode ray tube in a television receiver, etc.
Television receivers have focus circuits for supplying a direct-current focus voltage to a focus electrode of a cathode ray tube. By supplying this focus voltage, an electro-static lens for converging an electron beam is formed between the focus electrode and an anode electrode.
A dynamic focus circuit is widely used as the focus circuit for improving the focus characteristic In peripheral portions of a picture. This dynamic focus circuit supplies the direct-current focus voltage plus parabola voltages of horizontal and vertical periods to the focus electrode.
As mentioned above, the focus characteristic can be A 1 1 obtained to some extent by superimposing parabola voltages of horizontal and vertical periods onto the direct-current voltage. However, it has been found that the focus voltage is not optimum for focus on skew direction of the picture: the optimum focus was not obtained on all portions of the picture because the waveform of the optimum focus voltage for a cathode ray tube (hereinafter called CRT) is not a parabola wave form.
Accordingly, the present invention seeks to provide an improved focus-voltage generator for cathode ray tube which generates a focus voltage close to optimum for any portion of the picture. According to a first aspect of the present Invention, there is provided a focus-voltage generator for a cathode ray tube having a focus electrode, comprising a direct-current focus-voltage generator for generating a direct-current focus voltage, a dynamic focus- voltage generator for generating dynamic focus voltages for a horizontal and a vertical period, a superimposing circuit superimposing the dynamic focus voltage for the horizontal and the vertical periods from the dynamic focus-voltage generator onto the directcurrent focus voltage from the direct-current focus-voltage generator, and a focus voltage supply means for supplying the output focus voltage from the superimposing circuit to the focus electrode of the cathode ray tube, wherein the dynamic focus-voltage generator includes a first focus-voltage generator for generating a dynamic focus voltage of horizontal period, a second focus-voltage generator for generating a dynamic focus voltage for the vertical period, and a modulator for modulating the output from the first focus-voltage generator with the vertical period.
According to a second aspect of the present invention, there is provided a focus-voltage generator 1 for a cathode ray tube having a focus electrode, comprising a direct- current focus-voltage generator for generating a direct-current focus voltage, a dynamic focus-voltage generator for generating a dynamic focus voltage for a horizontal period, a superimposing means for superimposing the dynamic focus voltage for the horizontal period onto the output of the direct-current focus-voltage generator, and a focus voltage supply means for supplying the output of the superimposing means to the focus electrode of the cathode ray tube wherein the dynamic focus-voltage generator generates dynamic focus voltage which is flatter at the centre portion of the picture and rises more sharply at the edge portions of the picture than a parabola voltage waveform.
According to a third aspect of the present invention, there is provided a focus-voltage generator for a cathode ray tube having a focus electrode, comprising a direct-current focus-voltage generator for generating a direct-current focus voltage, a dynamic focus-voltage generator for generating a dynamic focus voltage for a horizontal period, a superimposing means for superimposing the dynamic focus voltage for the horizontal period onto the dynamic focus voltage for the horizontal period onto the output of the directcurrent focus-voltage generator, and a focus voltage supply means for supplying the output of the superimposing means to the focus electrode of the cathode ray tube wherein the dynamic focus-voltage generator includes a drive-pulse supply circuit for tAe horizontal period, a transistor receiving the output of the drive-pulse supply circuit at its base, a damper diode and a resonance capacitor connected across the collector and the emitter of the transistor, a directcurrent power source, and an inductor connected between the collector of the transistor and the direct-current 1 power source and outputting the dynamic focus voltage for the horizontal period.
According to a fourth aspect of the present invention, there is provided a method of generating a focus voltage for a cathode ray tube having a focus electrode, comprising:
generating a direct-current focus voltage with a first focus-voltage generator; generating with a second focus-voltage generator a horizontal-period dynamic focus voltage which is flat and at a low level near the centre portion of a picture to be displayed by the cathode ray tube and rises sharply at the edge portions of the picture; generating with a third focus-voltage generator a vertical-period dynamic focus voltage which is flat and at a low level near the centre portion of a picture to be displayed by the cathode ray tube and rises sharply at the edge portions of the picture; modulating in a modulator the horizontal-period dynamic focus voltage with the vertical period; superimposing the output of the modulator and the vertical-period dynamic focus voltage onto the directcurrent focus voltage; and supplying the superimposed signal to the focus electrode.
Other features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
1 W f A more complete appreciation of the present invention and many of Its attendant advantages will be readily obtained by reference to the following. detailed description considered in connection with the accompanying drawings, in which:
Figure 1 provides a circuit diagram of a generator of a focus voltage for a cathode ray tube according to the present invention.
Figure 2 illustrates waveforms at some points of the generator of a focus voltage for a cathode ray tube shown in Figure 1.
Figure 3 provides a circuit diagram of one example of the wave form generating circuit shown in Figure 1.
Figures 4 to 5 provide other circuit diagrams, respectively, of a generator of a focus voltage for a cathode ray tube according to the present invention.
The preferred.embodiment Of the present invention will now be described in more detail with reference to the accompanying drawings.
Fig. 1 is a circuit diagram of a generator of L'focus voltage for a CRT of one embodiment of the invention.
t 1 1 1 This generator has 5 blocks, namely, a horizontal output circuit 100, an output circuit 200, a dynamic. focus voltage generating circuit for the horizontal period 300, a dynamic focus voltage generating circuit for the vertical period 400,'and a modulating circuit 500.
In the horizontal output circuit 100, a horizontal drive pulse supply circuit 102 supplies a horizontal drive pulse. The base of a horizontal output transistor 104 is connected to this circuit 102, the emitter is connected to the ground, and the collector is connected to one side of the primary winding L1 of a flyback transformer 106. A damper diode 108, a resonance capacitor 110, and a series circuit of a horizontal deflection coil 112 and a character compensation capacitor 114 are connected In parallel across the collector and the emitter of the transistor,104, respectively. The other side of the primary winding L1 of the flyback transformer 106 Is connnected to a direct-current source V=.
The secondary winding L2 of the flyback transformer 106 has a series circuit 202 of coils and diodes. One side of this secondary winding L2 is connected to an output terminal 204 which delivers a high anode voltage E. rom the output circuit 200, and the other side of the secondary winding L2 is connected to an ABL (Automatic Brightness LimiterY circuit which Is not shown. In the output circuit 200, a seties circuit of resistors 206 and 208 is connected between the 1.
i output terminal 204 and the ground. The output terminal 210 of the direct current focus voltage E F is connected at the.connection point of the resistors 206 and 208.
The dynamic focus voltage generating circuit for the horizontal period 300 is similar.to thh horizontal output circuit 100 in composition. The base of a transistor 302 is connected to a drive pulse supply circuit 304 which outputs the drive pulse of the horizontal period. A damper diode 306 and a series circuit of resonance capacitors 308 and 310 are connected across the collector and the emitter of the transistor 302, respectively. One side of the primary winding L3 of a pulse transformer 312 is connected tp.the collector of the transistor 302. Other side of the primary winding L3 of the pulse transformer 302 Is connected to a direct-current source WC2. The other side of the secondary,winding L4 of the pulse transformer 312 is connected to the output terminal 210 through a coupling capacitor 314. The other side of the secondary winding of the pulse transformer 312 is connected to the dynamic focus voltage generating circuit for the vertical period 400.
In the dynamic focus voltage generating circuit 400, the base of a transistor 402 is connected to the waveform generating circuit 404 which outputs a voltage wave form which is high at the center portion and is low at the peripheral portions during the vertical period. The' collector of the transistor 402 is connected to a power source WC3 through a resistor 406.
The collector of the transistor 402 is.also connected to the other side of the secondary winding L4 of the pulse transformer 312 and a capacitor 408 through a resistor 410. The capacitor 408 Is grounded. The emitter of the transistor 402 is grounded through a resistor 412.
The modulating circuit 500 is connected at the connection point of the capacitors 308 and 310. In the modulating circuit 500, the base of a transistor 502 is connected to a waveform generating circuit 504. A capacitor 506 and a series circuit of diodes 508 and 510 are connected across the collector and the emitter of the transistor 502. The connecting point of the diodes 506 and 508 Is connected to that of the capacitors 308 and 310.
Additionally, the waveform generating circuit 504 may.be replaced by the waveform generating circuit 404.
The operation of the above-described focus voltage generator Is detailed below.
In this focus voltage generator, the horizontal drive pulse (a rectangular wave) is input to the base of the transistor 104 from the drive pulse supply circuit 102. The output waveform from the collector of the transistor 104 (flyback pulse voltage) Is shown in Fig. 2(A). From the horizontal deflection coil 112, saw-tooth waveforms for horizontal scanning are obtained (a detailed descriptlon is omitted).
Z i t 1 The high anode voltage E H is obtained from the secondary winding L2 of the flyback transformer 106. The ordinary focus voltage is obtained from the connection point of the resistors 206 and 208.
The output waveform- fi?om the collector of the transistor 302 is shown in Fig. 2(B) which is similar to the waveform in Fig. 2(A). The pulse width of the waveform in Fig. 2(B) is designed to be broader than the horizontal flyback period by designing the primary winding L3 of the pulse transformer 312 and the characteristics of the resonance capacitors 308 and 310.
The output from the collector of the transistor 302,.obtained from the secondary winding L4 of the pulse transformer 312 after boosting the voltage if necessary, is superimposed onto the ordinary focus voltage through the coupling capacitor 314. By doing this, a dynamic focus voltage for the horizontal period is obtained which rises sharply to a high level at both sides of the picture.
Additionally, In the modulating circuit 500, the collector current of the transistor 502 is changed by the vertical period modulation signal from the waveform generating circuit 504. This change results in the effective modulation of the capacitance of the resonance capacitor 310. That is, the change brings a change of the resonance condition of resonance capac'Itors 308, 310 and the primary winding L3 of the pulse transformer i 'I 1 312. The peak-to-peak (hereinafter called p-p) value of the pulse wave form shown in Fig. 2(B) is thus modulated.. If the waveform generating circuit 504 supplies a raodulation voltage of a high level at the centre portion and of a low level at the peripheral portions to the base of the transistor 502, the dynamic focus voltage waveform for the horizontal period, which is superimposed on the directcurrent focus voltage, is modulated so that the p-p value of the voltage becomes small at the centre portion and becomes large at the peripheral portions. The focus voltages at the four corners of the picture become highest.
Additionally, In the dynamic focus voltage generating. circuit 400, If the waveform. generating circuit 404 supplies a voltage waveform having a vertical period (rising more sharply to a high level than the parabola wave -form at the peripheral portions, and comparatively flatter than the parabola wave form at the centre portion) such as shown In Fig. 2(C), or a similar voltage waveform such as a rectangular wave form, to the collector of the transistor 402, the focus voltage shown in Fig. 2(D), more suited to the characteristics of a CRT, is obtained at the secondary winding L4 of the pulse transformer 312.
The phases of the dynamic focus voltage waveform for the horizontal period and the picture may coincide if the drive pulse supply circuit 304 has a means for modulting the phase of the drive pulse with the vertical period. This 1 j modulating signal may be supplied from the waveform generating circuit 404. Fig. 3 shows a circuit diagram of one example of the waveform generating circuit 404.
This circuit 404 uses an output of a vertical deflection circuit in a CRT.
An Input terminal 404a receives a vertical deflection voltage. A vertical deflection coil 404b is connected to the input terminal 404a. An electrolytic capacitor 404c is connected to the coil 404b. A feedback resistor 404d is connected between the capacitor 404c and the ground. The portion of the circuit surrounded by the dotted line is in the CRT in general. A non-inverting input of an operational amplifier 404e Is connected at the connection point of the capacitor 404c and the resistor 404d. An inverting input of the amplifier 404e is grounded through a constant voltage.source 404f. The output of the amplifier 404e is connected to the output terminal 404g of the circuit 404 and is also connected to a zener diode 404h which is grounded. A feedback capacitor 404i is connected between the output and the non-inverting input terminal of the amplifier 404e.
In this circuit, saw-tooth waveforms are obtained for vertical deflection from the connection point between the coil 404b and the capacitor 404c. The voltage waveform being high at the center portion and low at the edge portions of the picture, which waveform is detailed above, is output from output terminal 404g.
1 1 Fig. 4 Is a circuit diagram of another embodiment of the Invention.
In the above-described embodiment shown in Fig. 1, the equivalent capacitance of the resonance capacitor is modulated to modulate the p-p value of the focus waveform with a vertical period.
In this embodiment, the voltage of the power source of the dynamic focus voltage generating circuit 300 in Fig. 1 Is modulated instead. That is, the difference between the embodiments shown In Figs. 1 and 4 is that in the embodiment shown In Fig. 4, there is no capacitor 310 used as a resonance capacitor, no modulating circuit 500, and there is a power source voltage control circuit 600 between the primary winding L3 of the pulse transformer 312 and the direct-current power source WC2.
The power voltage control circuit 600 has a waveform generating circuit 602 which generates a modulation signal for the vertical period. This circuit 602 generates a wavt-form similar to that of the waveform generating circuit 404. The circuit 404 may be. used instead of the circuit 602.
The bise ofa transistor 604 is connected to the circuit 602 and the emitter is grounded. The collector of the transistor 604 is connected to the base of a transistor 606 through a resistor 608. The emitter and the collector of the transistor 606 are connected to the primary winding i j 1 1 1 i 1 1 i 2 L3 of the pulse transformer 312 and the direct-current power source WC2, respectively. A resistor 610 is connected between the base and the collector of the transistor 606.
The operation of this embodiment is detailed below. However, the operation of this embodiment, except for the power voltage control circuit 600, is the same as that of the embodiment shown in Fig. 1. Thus, only the operation of the power voltage control circuit 600 is described below.
The voltage across the collector and the emitter of the drive transistor 604 (i.e. the voltage at the base of the transistor 606 for voltage control) is changed. And the voltage at the emitter of the transistor 606 is modulated by the modulation signal from the circuit 602. Thus, the p-p value of the dynamic focus voltage waveform for the horizontal period is modulated.
Fig. 5 Is a circuit diagram of a third embodiment of the invention. - This embodiment is adapted for CRTs such as small CRTs which may not need modulation with the vertical period in the dynamic focus of the horizontal period. That is, in the third embodiment, the dynamic focus voltage generating circuit and the power voltage.control circuit 600 are eliminated fram the embodiment shown in Fig. 4. An inductor 316 is used instead of the pulse transformer 312.
The inductor 316 is connected the capacitor 314 and a power source WC. The inductor 316 generates a dynamic focus voltage waveform for the horizontal period. This dynamic focus voltage waveform is superimposed on the direct-current focus voltage from the connection point of the resistors 206 and 208 through the capacitor 314.
The dynamic focus voltage waveform formed by the Inductor 316 rises more sharply at the peripheral portions and Is flatter at thecentre portions of the picture than the parabola waveform- \ 1 1 1
Claims (11)
1. A focus-voltaqe generator for a cathode ray tube having a focus electrode, comprising a direct-current focus-voltage generator for generating a direct current focus voltage, a dynamic focus-voltage generator for generating dynamic focus voltages for a horizontal and a vertical period, a superimposing circuit superimposing the dynamic focus voltage for the horizontal and the vertical periodsfrom the dynamic focus-voltage generator onto the direct-current focus voltage from the direct-current focus voltage generator and a focus voltage supply means for supplying the output focus.voltage from the superimposing circuit to the focus electrode of the cathode ray tube, wherein the dynamic focus-voltage generator includes a first focus-voltage generator for generating a dynamic fo.ctis voltage of horizontal period, a second focus-voltage generator for generating a dynamic focus voltage for the vertical period, and a modulator for modulating the output from the first focus-voltage generator with the vertical period.
2. A focus-voltage generator for a cathode ray tube according to Claim 1wherein the first focus-voltage generator comprises:
a horizontal-period drivepulse supply circuit a transistor drive pulse at its base a damper diode connected across the transistor a direct-current power source a pulse transformer having a primary winding connected between the direct-current power source the collector of the transistor and a secondary winding outputtinq the dynamic focus voltage for the horizontal period.
receiving the horizontal period.
and a resonance capacitor the collector and the emitter of and
3. A focmltaqe generator for a cathode ray tube according to Claim 2, wherein the modulator is connected to-the resonance capacitor - and modulates the equivalent capacitance ofthe resonance capacitor with the vertical period.
4. A focus-voltage generator for a cathode ray tube according to Claim 2, wherein the modulator is connected between the direct-current power source and the primary winding of the pulse transformer and modulates the voltage of the direct-current power source supplied to the primary winding of the pulse transformer with the vertical period.
2 1 1 1
5. A focus-voltage generator for a cathode ray tube according to Claim 2, wherein the second generator connected to the secondary winding of the pulse transformer
6. A focus- voltage generator for a cathode ray tube according to Claim 1, wherein the first focus-voltage generator generates the dynamic focus voltage which is f latter at the centre portion of the picture and rises more sharply at the edge portions of the picture than a parabola voltage waveform, the second focus-voltage generator generates the dynamic focus voltage which is flatter at the centre portion of the picture and rises more sharply at the edge portions of the picture than a parabola voltage wave form, and the modulator modulates the output from the first focus---voltagegenerator so that the peak:!-t6-peak value of the output becomes small at the center portion of the picture and becomes large at the edge portions of the picture.
7. A focus-voltage generator for a cathode ray tube having a focus electrode, comprising a direct-current focus-voltage generator for generating a direct-current focus voltage, a dynamic focus-voltage generator for generating a dynamic focus voltage for a horizontal period, a superimposing means for superimposing the dynamic focus voltage for the horizontal period onto the output of the direct-current focus-voltage generator, and a focus voltage supply means for supplying the output of the superimposing means to the focus electrode of the cathode ray tube wherein the dynamic fociis-voltage generator generates a dynamic focus voltage which is flatter at the centre portion of the picture and rises more sharply at the edge portions of the picture than a parabola voltage waveform.
8. A focusltage generator for a cathode ray tube having a focus electrode, comprising a direct-current focus-voltage generator for generating a direct-current focus voltage, a dynamic focus-voltage generator for generating a dynamic focus voltage for a horizontal period, -a superimposing means for superimposing the dynamic focus voltage for the horizontal period onto the output of the direct-current focus-voltage generator, and a focus voltage supply means for supplying the output of the superimposing means to the focus electrode of the cathode ray tube wherein the dynamic focus-voltage generator Includes a drive-pulse supply circui.t for the horizontal period, a transistor receiving the output of the drive-pulse supply circuit at its base, a damper diode and a resonance capacitor connected across the collector and the emitter of 1 1 0 A the transistor, and an inductor 1 a d'.lrect-current power source connected between the collector of the transistor and the direct-current power source and output-ting the dynamic focus voltage for the horizontal period.
9. A method of generating a focus voltage for a cathode ray tube having a focus electrode, comprising:
generating a direct-current focus voltagewith a first focus-voltage generator generating with a second f ocus-voltage generator a horizontal-period dynamic focus voltage which is flat andat a low level near the centre portion of a picture to be displayed by the cathode ray tube and rises sharply at the edge portions of the picture; generating with a third focus -voltage generator a vertical-period dynamic focus voltage which isflat and at a low level near the centre portion of a picture to be displayed by the cathode ray tube and rises sharply at the edge portions of the picture; modulating in a modulator the horizontal period dynamic focus voltage with the vertical period; superimposing the output of the modulator and the vertical-period dynamic focus voltage onto the direct-current focus voltage; and supplying the superimposed signal to the focus 1 1 electrode.
10. A focus-voltage generator for a cathode ray tube substantially as described hereinbefore with reference to the drawings.
11. A method for generating a focus voltage for a cathode tube ray substantially as described hereinbefore with reference to the drawings.
r Publish d 1991 atThe PatentOffice. State House. 66171 HighHolborn. London WC1R41P. Further copies may be obtained from Sales Branch, Unit 6. Wince Mile Point Cwmfelinfach. Cross Keys. Newport. NPI 7HZ. Printed by Mulfiplex techniques lid, St Mary Cray, Kent.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1324821A JPH03184479A (en) | 1989-12-13 | 1989-12-13 | Focus voltage generator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9027094D0 GB9027094D0 (en) | 1991-02-06 |
| GB2239148A true GB2239148A (en) | 1991-06-19 |
Family
ID=18170052
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9027094A Withdrawn GB2239148A (en) | 1989-12-13 | 1990-12-13 | Dynamic focus voltage generator |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPH03184479A (en) |
| KR (1) | KR940008800B1 (en) |
| DE (1) | DE4039838A1 (en) |
| GB (1) | GB2239148A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL9301756A (en) * | 1992-12-17 | 1994-07-18 | Samsung Display Devices Co Ltd | dynamically focusing electron gun. |
| EP0682446A2 (en) * | 1994-05-11 | 1995-11-15 | Thomson Consumer Electronics, Inc. | High voltage vertical dynamic focus amplifier |
| GB2292296A (en) * | 1994-08-08 | 1996-02-14 | Lg Electronics Inc | Dynamic focus circuit |
| EP0720353A1 (en) * | 1994-12-28 | 1996-07-03 | Thomson Consumer Electronics, Inc. | Dynamic focus coupling |
| US6504326B2 (en) | 2000-06-08 | 2003-01-07 | Koninklijke Philips Electronics N.V. | Focusing circuit for a cathode ray tube |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6115085A (en) * | 1998-06-19 | 2000-09-05 | Thomson Licensing S.A. | Focus voltage tracking circuit |
| CN1189015C (en) * | 1998-08-14 | 2005-02-09 | 索尼公司 | Scanning speed modulating circuit for picture display |
| JP3581310B2 (en) | 2000-08-31 | 2004-10-27 | Ｔｄｋ株式会社 | Semiconductor wafer processing equipment with dustproof function |
| US7537425B2 (en) | 2002-12-30 | 2009-05-26 | Tdk Corporation | Wafer processing apparatus having dust proof function |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60160267A (en) * | 1984-01-30 | 1985-08-21 | Pioneer Electronic Corp | Dynamic focus circuit |
-
1989
- 1989-12-13 JP JP1324821A patent/JPH03184479A/en active Pending
-
1990
- 1990-12-13 GB GB9027094A patent/GB2239148A/en not_active Withdrawn
- 1990-12-13 KR KR1019900020464A patent/KR940008800B1/en not_active IP Right Cessation
- 1990-12-13 DE DE4039838A patent/DE4039838A1/en not_active Ceased
Non-Patent Citations (1)
| Title |
|---|
| IBM Technical Disclosure Bulletin, Vol.31, No.2, July 1988, pages 263 to 265 * |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL9301756A (en) * | 1992-12-17 | 1994-07-18 | Samsung Display Devices Co Ltd | dynamically focusing electron gun. |
| EP0682446A2 (en) * | 1994-05-11 | 1995-11-15 | Thomson Consumer Electronics, Inc. | High voltage vertical dynamic focus amplifier |
| EP0682446A3 (en) * | 1994-05-11 | 1996-03-27 | Thomson Consumer Electronics | High voltage vertical dynamic focus amplifier. |
| GB2292296A (en) * | 1994-08-08 | 1996-02-14 | Lg Electronics Inc | Dynamic focus circuit |
| GB2292296B (en) * | 1994-08-08 | 1998-12-30 | Lg Electronics Inc | Dynamic focus circuit |
| EP0720353A1 (en) * | 1994-12-28 | 1996-07-03 | Thomson Consumer Electronics, Inc. | Dynamic focus coupling |
| US5565746A (en) * | 1994-12-28 | 1996-10-15 | Thomson Consumer Electronics, Inc. | Dynamic focus coupling |
| CN1110940C (en) * | 1994-12-28 | 2003-06-04 | 汤姆森消费电子有限公司 | Dynamic focus coupling |
| US6504326B2 (en) | 2000-06-08 | 2003-01-07 | Koninklijke Philips Electronics N.V. | Focusing circuit for a cathode ray tube |
Also Published As
| Publication number | Publication date |
|---|---|
| KR940008800B1 (en) | 1994-09-26 |
| GB9027094D0 (en) | 1991-02-06 |
| KR910013853A (en) | 1991-08-08 |
| DE4039838A1 (en) | 1991-07-11 |
| JPH03184479A (en) | 1991-08-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |