KR20010089166A - Color display device having quadrupole convergence coils - Google Patents

Abstract

The present invention provides an inline electron gun 5 for generating three electron beams 6, 7 and 8, a convergence unit 14 ′ which dynamically affects the convergence of the electron beam, and the electron beams 6, 7 and 8. It relates to a color display device comprising a deflection means 51 for deflecting < RTI ID = 0.0 > Convergence unit 14 'comprises a ring-shaped element 21', the ring-shaped element comprising two parts, the first part 60 being the inline electron gun 5 rather than the second part 68. Closer to, the first and / or second portions have four coils 22 'that produce a four-pole magnetic field.

Description

COLOR DISPLAY DEVICE HAVING QUADRUPOLE CONVERGENCE COILS with 4-pole convergence coil

Such display devices are known.

The conventional purpose is to make the outer surface of the color display window flatter so that the image displayed on the display window is perceived by the viewer as flat. However, increasing the radius of curvature of the outer surface will cause an increase in many problems. The radius of curvature of the color selection electrode and the inner surface of the display window should increase, and as the color selection electrode becomes flatter, the mechanical strength of the color selection electrode decreases, thus increasing the sensitivity to doming and vibration. An alternative solution to this problem is to bend the inside of the display window larger than the outside. Because of this, a color selection electrode having a relatively small radius of curvature can be used. Because of this, the domming and vibration problems are reduced, but other problems occur instead. The display window is much thicker on the edge than the center. Therefore, the weight of the display window increases, and the image intensity decreases substantially as it goes out.

European patent EP 0,421,523 describes a color cathode ray tube with an in-brow gun, a pincushion correcting yoke and an eyebrow effect electron-optical distortion correction device comprising two pairs of coils. Each pair has a coil in the beam plane, on each outer electron beam side of the neck. Coil pairs are sawtooth waves with a bow-tie envelope, spaced along the Z axis between the electron gun and the yoke and synchronized with the raster scan to correct dynamic and asymmetric eyebrow effects, which are manifested as purity defects on the raster. Driven by current.

International patent WO 99/34392 discloses an inline electron gun for generating three electron beams, deflection means for deflecting an electron beam located at the deflection plane with a color selection electrode, and a dynamic influence on the convergence of the electron beam at the deflection plane position. A color display device is described, comprising a color cathode ray tube with first and second influencing means for reducing the distance between electron beams.

The presence of induction means can cause some unwanted imaging defects. It can affect the so-called East / West raster distortion and also affect the electron beam linearity of the deflection in the vertical direction. In conventional cathode ray tubes, deflection in the vertical direction is not a linear function of deflection current. This nonlinearity is corrected electronically. The introduction of the first and second inducing means results in a cathode ray tube in which the nonlinearity is reduced or even overcompensated. These results are undesirable.

The present invention relates to a color display device comprising an in-line electron gun for generating three electron beams, and a unit for deflecting the electron beam across the color selection electrode.

1 is a cross-sectional view of a color display device.

2a and 2b show ring-shaped elements of the first part and the second part according to the invention;

3 shows a deflection unit according to the invention.

4A and 4B illustrate an embodiment of the present invention.

The figures are not drawn to scale. In the drawings, like reference numerals refer to like parts throughout.

It is an object of the present invention to provide an improved color display device. For this purpose, the present invention provides a deflection unit and color display device as defined in the independent claims. The dependent claims describe advantageous embodiments.

These and other objects of the present invention will become apparent and clear with reference to the embodiments described below.

The display device shown in FIG. 1 comprises a color cathode ray tube having a display window 2, a conical portion 3 and an evacuated envelope 1 comprising a neck 4. The neck 4 has an inline electron gun 5 which produces three electron beams 6, 7 and 8 directed in the X direction of the vertical X-Z coordinate system, ie in the in-line plane. In the unbiased state, the central electron beam 7 substantially coincides with the central axis 9 of the cathode ray tube, which is directed in the Z direction. The third direction, the Y direction, is directed in a direction perpendicular to the inline plane (not shown in the figure). In general, during operating operating conditions, the cathode ray tube is positioned in such a way that the X-Z plane coincides with the horizontal plane and the Y direction coincides with the vertical direction.

The display screen 10 is provided on an inner surface of the display window. The display screen 10 includes a number of phosphorescent elements emitting red, green and blue. On the way to the display screen, the electron beam is deflected across the display screen by an electromagnetic deflection unit 51 and comprises a thin plate disposed in front of the display window 2 and having apertures 12. The color selection electrode 11 passes through. Since the three electron beams 6, 7 and 8 pass through the aperture 12 of the color selection electrode at a small angle with respect to each other, each electron beam hits only one phosphor element of one color. The deflection unit 51 includes, in addition to the coil holder 13, a deflection coil 13 ′ which deflects the electron beam in two directions perpendicular to each other. The ring shaped element 21 ', the so-called yoke ring, is located around the deflection coil 13'. The reason for using the yoke ring (usually containing ferrite) is to "short-circuit" the magnetic flux outside the coil. Without the yoke ring, an excessively large current passing through the deflection coil It will be common, and also disturbing stray fields will occur The display device also includes means for generating a voltage for supplying the electron gun component through feedthroughs during operation. The surface 20 is schematically shown, and the distance p between the electron beams 6 and 8 is also shown on this surface, and the distance q between the color selection electrode and the display screen is also shown. Inversely proportional to distance p.

The color display device comprises two beam convergence inducing units 14, 14 ′, which, during operation, dynamically move the outermost electron beams towards each other as a deflection function in one direction. Used to bend, the second unit 14 'dynamically bends the outermost electron beam in the opposite direction. Unit 14 bends the electron beams toward each other, and unit 14 'bends the electron beams in the opposite direction. As a result, the distance between the deflected electron beams becomes smaller than the distance between unbiased beams. Since the distance p is smaller, the distance q can be increased, which frees up the design regarding the curvature of the color selection electrode. In design, this freedom increases the curvature of the color selection electrode, which positively affects the color selection electrode strength, and reduces the sensitivity to domming and vibration.

The two units 14, 14 ′ are located at a constant distance from each other. The first unit 14 is located close to the electron gun and is called a "gun quadrupole", and the second unit 14 'is located close to the deflection unit or this deflection unit and is referred to as "yoke quadrupole". It is called. It is easy to integrate the unit 14 'and the deflection unit 51 by winding four coils around the ring-shaped element 21' to create a dynamic four-pole electromagnetic field.

In operation, the units 14, 14 ′ affect the deflection of the electron beams, which may cause unwanted defects in the image displayed in the window 2.

In a conventional cathode ray tube (CRT), the deflection in the vertical (Y axis) direction is a nonlinear phenomenon, that is, the displacement of the electron beam is not a linear function of the current passing through the deflection coil. The deflection of the beams requires a relatively small current on the extreme sides of the display window. An electronic method of correcting nonlinearity, called vertical S-correction, takes place in a television receiver to which the cathode ray tube is applied. Due to the operation of the yoke quadrupole, the deflection of the electron beam becomes a more linear process, which means that the S-correction overcorrects the non-linear deflection phenomenon. This is not desirable.

Existing CRTs are also corrected for so-called east / west pincushion raster distortion, where east and west represent two vertical sides of the display window. This means that the image consisting of the horizontal and vertical lines of the right angle raster is displayed on the screen in the form of a distorted cushion, where the vertical lines of the raster near the boundary of the display window are bent inward. This appears to be the application of unit 14'increasing such image defects.

It is an object of the present invention to reduce the effect of unit 14 'on the previously mentioned image defects. The present invention is based on the recognition that the unit 14 'has its main influence on the side of the ring-shaped element 21' facing the display window 2. Therefore, it is proposed to divide the ring-shaped element 21 'into two (divided by axes) parts and wind a four-pole coil on one side of these two parts. Preferably, a four pole coil is wound around the core portion closest to the electron gun. The measurement gives the opportunity to move the two core parts independently of each other, thus improving the raster and convergence performance of the cathode ray tube.

2A and 2B show an embodiment of the present invention. 2a shows a first part 60 of the ring-shaped element 21 ′, which is closest to the electron gun 5. This part 60 has four coils 22 'that produce a four-pole magnetic field. Coils are shown wound around a ring-shaped element in a toroidal way. However, this manner of winding is not essential to the present invention. The quadrupole coil can also be wound in a saddle-like shape around the ring shaped element. In order to facilitate the winding process and to maintain the individual wire elements of the coil 22 ′ in the proper position of the first part 60, the first part is located where the wound coil is located. Rings 64 and 66 with grooves are provided at their ends. 2b shows a second portion 68 of the ring-shaped element 21 ′, which is closest to the display window 2. When applied to a cathode ray tube, these two parts 60, 68 can be connected to one another by any existing connection means, ie adhesives or tapes. The connection between these two parts is not essential for proper performance.

3 shows the two parts 60, 68 according to the invention when the two parts 60, 68 are located around the deflection coil 13 ′ and the coil holder 13. The first portion 60 has four coils 22 'and rings 64, 66 that generate a four-pole magnetic field.

4A and 4B show an embodiment of the invention, wherein the coil 22 ′ around the first portion 60 of the ring-shaped element 21 is an electrical conductor, which is N ( ) = N ₀ cos (2 Winding density distribution given by }), It is wound in a winding direction in the form of a donut. here, Is the angle surrounded by the X-direction and the line connecting the coil element to the center, the range of which is between 0 ° and 360 °, N ₀ is Winding density when is 0 °, N ( ) Indicates the winding direction.

This embodiment has the advantage that almost pure quadrupole magnetic fields can be generated, that is, the presence of other multipolar magnetic fields is greatly suppressed.

Since the line size is finite, in practice it can only be realized as an approximation of the winding density. In this embodiment, the winding density, that is, N ( ) = N ₀ cos (2 ), A package 30 made of an electric conductor is wound around the yoke ring 21 'along a donut shape.

In this particular embodiment, the electrical leads are wound in the grooves 34 of the rings 64, 66, 15 degrees apart from each other. Winding method is as follows.

= 18 turns in a groove at 0 ° (a position),

= 15 turns in groove with 15 ° (b position),

= 9 turns at 30 ° (c position),

= 45 ° (d position) without detection

In a groove with = 60 ° (e position), wind nine times in the opposite direction,

= 15 turns at 75 ° (f position),

= 90 ° (g position), 18 turns. Ideal winding density {N ( This approximation to) proves to be in fact good.

In summary, the present invention provides an inline electron gun 5 for generating three electron beams 6, 7 and 8, a convergence unit 14 ′ which dynamically affects the convergence of the electron beams, and an electron beam 6, 7 and 8. It relates to a color display device comprising a deflection means 51 for deflecting < RTI ID = 0.0 > The convergence unit 14 'comprises a ring-shaped element 21', which in turn comprises two parts, the first part 60 being in the inline electron gun 5 rather than the second part 68. Closer, this first and / or second portion has four coils 22 'that generate a four-pole magnetic field.

It should be noted that the foregoing embodiments are intended to illustrate, not limit the invention, and those skilled in the art can design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprises" and their conjugates does not exclude the presence of elements or steps other than those stated in a claim. Singular words used herein do not exclude the presence of a plurality of such elements.

Claims (5)

An in-line electron gun 5 for generating three electron beams 6, 7 and 8, deflection means 51 for deflecting the electron beams 6, 7 and 8, and a ring-shaped element 21 ′. A color display device comprising a convergence unit 14 'that dynamically affects the convergence of the electron beam, The ring-shaped element 21 ′ comprises two parts 60, 68, the first part 60 being closer to the inline electron gun 5 than the second part 68, and the first part ( 60) and / or the second portion (68) is characterized in that it comprises four coils (22 ') for generating a four-pole magnetic field. The method of claim 1, wherein the coils 22 ', N ( ) = N ₀ cos (2 Winding density distribution given by )}, In the direction of toroidally winding, comprising a wound electrical conductor, wherein Is an angle surrounded by a line connecting the coil element with the center in the X direction, and the range is between 0 ° and 360 °, and N ₀ is Winding density when is 0 °, N ( Denotes the wound direction. 2. The coil of claim 1 wherein the coils 22 'comprise a package 30 of electrical conductors, the package 30 being N ( ) = N ₀ cos (2 Winding density distribution given by )} Is wound in the direction of winding in the form of a donut, where Is an angle surrounded by the X direction and a line connecting the element and the center of the package. Deflection coils 13, 13 ′, and convergence means 14 ′ that dynamically affect the convergence of the electron beams 6, 7, and 8, wherein the convergence means 14 ′ are ring-shaped elements 21 ′. Wherein the ring-shaped element comprises two portions 60, 68, wherein the first portion 60 is located closer to the inline electron gun 5 than the second portion 68. 60) and / or the second portion (68) comprises four coils (22 ') generating a four-pole magnetic field. 5. The coil of claim 4 wherein the coils 22 ' ) = N ₀ cos (2 Winding density distribution given by ), In the direction of winding in the form of a donut, comprising the wound electrical conductor, wherein Is an angle surrounded by a line connecting the coil element with the center in the X direction, and the range is between 0 ° and 360 °, and N ₀ is Winding density when is 0 °, N ( Is a deflection unit (51).