JP2565863B2 - Color picture tube device - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an improvement of an in-line type color picture tube device.

[Technical background of the invention]

The envelope of the color picture tube comprises a neck containing a three-electron gun, a face plate having a fluorescent screen, and a funnel interposed between the neck and the face plate.

The three-electron gun is mounted in the neck in a horizontal direction in an in-line shape, and the emitted electron beam is made to strike the fluorescent surface on which the fluorescent material layer is formed to emit light.
In order to realize the light emission of the phosphor layer with good color reproducibility, it is necessary to selectively project the electron beam onto a predetermined phosphor layer. Therefore, a shadow mask with a large number of apertures is close to the face plate. Are placed.

The in-line electron gun is designed to generate three electron beams on a common plane by a cathode and concentrate these three electron beams in the vicinity of the face plate. A method of concentrating three electron beams is disclosed in, for example, US Pat. No. 295710.
There is a technique in which an electron beam emitted from a cathode is inclined from the beginning as shown in US Pat. Among the 3 electron beam passage apertures, there is a technique that concentrates the electron beam by slightly displacing the apertures on both sides of the electrode to the outside of the central axis of the electron gun. Has been done.

In order to display a television image on the screen (fluorescent screen) of a color picture tube, a deflecting device for scanning the electron beam emitted from the electron gun over the entire fluorescent screen is required. This is located outside the funnel cone. Mounted. The deflection device basically has a horizontal deflection coil for generating a horizontal deflection magnetic field for horizontally deflecting the electron beam and a vertical deflection coil for generating a vertical deflection magnetic field for vertically deflecting the electron beam. ing. In an actual color picture tube device, when the electron beam is deflected, the concentration of the three electron beam spots on the face plate is lost,
Some measures have been taken to prevent this loss of concentration.
This is called a convergence-free system, in which the horizontal deflection magnetic field is a pincushion type and the vertical deflection magnetic field is a barrel type so that three electron beams are concentrated on the entire phosphor screen. As a result, this system eliminates the need for a parabola current generation circuit for convergence correction and a convergence yoke for generating a convergence correction magnetic field, which results in many effects such as cost reduction and productivity improvement.

[Problems of background technology]

As described above, the quality of the color CRT has been improved by adopting many development techniques, but new problems are being highlighted as the size of the tube becomes widespread.

That is, the beam spot emitted from the three-electron gun and concentrated on the face plate presents only a circular core at the center of the screen that is not deflected, but a flat core at the peripheral portion of the screen where the deflection is directed. And offers flares that spread up and down. As a result, the size of the electron beam increases at the peripheral portion of the screen, and the focus performance and the resolution deteriorate.

[Object of the Invention]

The present invention has been made in order to solve the above-mentioned conventional drawbacks. Instead of the conventional convergence-free system, a bright high-resolution color is obtained over the entire screen with less distortion of the electron beam spot at the peripheral portion of the screen. An object is to provide an image receiving device.

[Outline of Invention]

The present invention provides a neck in which three electron guns are horizontally installed inline, and three colors of red, green, and blue are formed by a bombardment of an electron beam emitted from the electron gun on the inner surface of the neck connected to the neck through a funnel. A face plate having a fluorescent surface on which a phosphor layer for emitting light is regularly formed and deposited, and a large number of apertures arranged in proximity to the face plate for selectively projecting the electron beam onto the phosphor layer. In a color picture tube device having a shadow mask and a deflection device which is mounted on the outer wall of the funnel and generates a horizontal deflection magnetic field for horizontally deflecting an electron beam emitted from the electron gun and a vertical deflection magnetic field for vertically deflecting the electron beam. The three electron beams emitted from the electron gun are substantially parallel to each other, the horizontal deflection magnetic field forms a substantially uniform magnetic field distribution, and the vertical deflection magnetic field Generated by applying different currents to a pair of coils arranged on the lower side and the lower side, and the shape of the magnetic field is vertically asymmetrical with respect to the horizontal plane including the color picture tube axis and in the vertical direction including the color picture tube axis. The color picture tube device is characterized in that it is composed of a deflection magnetic field which is symmetrical with respect to.

Example of Invention

The present invention will be described below based on examples. FIG. 1 is a schematic sectional view of a 20-inch 90-degree deflection color picture tube device of the present invention.

(1) is a face plate, (2) is a funnel,
(4) is a neck, both made of glass. Red (R), green (G), blue (B) on the inner surface of the face plate (1)
Phosphor dots or phosphor stripes that emit light of each color are regularly arranged to form a phosphor screen (5) for image display.
A shadow mask (6) is arranged in close proximity to the phosphor screen (5). The shadow mask (6) is usually made of a thin iron plate having a dome shape similar to the inner surface of the face plate (1), so that the electron beam can correctly hit the phosphor at the portion facing the phosphor screen (5). It has a large number of open holes.

Inside the neck (4), three electron guns (7) corresponding to three colors of red, green and blue are enclosed. This three-electron gun is arranged in a line in the horizontal direction so that the emitted electron beams are parallel to each other with an interval of about 6.6 mm. Each electron gun is a cathode control electrode of an electron beam source,
It is composed of a closing electrode, a focusing electrode, and a high-voltage electrode, to which a predetermined voltage is applied. The high-voltage electrode voltage is usually an ultra-high voltage of 25 kv, and the inside of the color tube is maintained at a constant voltage of 25 kv.

The vicinity of the neck (4) connection part of the funnel (2) is called a cone part (3), and the deflecting device (9) is usually attached to this part.

The deflection device includes a horizontal deflection magnetic field that generates a magnetic field that horizontally deflects the electron beam and a vertical deflection magnetic field that generates a magnetic field that vertically deflects the electron beam.

The horizontal deflection magnetic field will be described. FIG. 2 shows the magnetic field shape of the horizontal deflection coil of the present invention.

FIG. 3 shows the shape of the beam spot at the peripheral portion of the screen. (A) shows the beam spot shape of the present invention,
(B) is a conventional beam spot shape using a pincushion type magnetic field shape.

In the present invention, the uniform magnetic field as shown in FIG. 2 greatly improves the shape of the horizontally deflected electron beam spot.

Next, the vertical deflection magnetic field will be described. FIG. 4 shows an example of a vertically asymmetrical deflection magnetic field shape used in the present invention when viewed from the screen side. (A) shows a state in which an electron beam is deflected upward, and (b) shows a downward deflection. It shows the situation when doing. FIG. 5 shows the balance of currents applied to the upper and lower toroidal winding coils of the deflection yoke in association with the deflection direction and the deflection amount, and the horizontal axis represents the time axis t. In FIG. 5, the solid line energizes the coil placed on the lower side while the electron beam scans one screen, and the broken line energizes the coil placed on the upper side while the electron beam scans one screen. The current is shown as
The currents shown by the solid line and the broken line corresponding to arbitrary points in the above flow in the coils arranged on the lower side and the upper side, respectively, and the solid line and the broken line intersect on the time axis t.

In this asymmetric deflection magnetic field, the distance D between the magnetic field symmetry axis and the electron beam axis increases as the strength of the deflection magnetic field increases. That is, in the structure of the present invention, the electron beams on both sides receive an outward force in proportion to the strength of the asymmetric magnetic field, and have the effect of widening the electron beam interval when deflected to the vertical axis end. By appropriately selecting the strength of the asymmetric magnetic field, the beam spacing at the vertical axis end can be made equal to the spacing at the center of the screen.

This asymmetric magnetic field can minimize the deflection distortion of the electron beam spot. That is, in the asymmetric magnetic field shown in FIG. 4, the correction strength of both side beam intervals is determined in proportion to the strength of the magnetic field. In other words, the relationship between the beam interval correction and the distortion amount of each beam at that time is in a proportional relationship. In contrast,
In the conventional vertically symmetrical vertical deflection magnetic field, the beam spacing cannot be corrected when each electron beam is not deflected or is slightly deflected.

On the other hand, the distortion itself of each beam naturally causes a large distortion because the magnetic flux density varies depending on the position as is clear from the figure.

FIG. 6 schematically shows the beam shape on the screen of a color picture tube using the vertically asymmetric additional deflection magnetic field of the present invention. Seventh
The figure schematically shows the beam shape of a conventional color picture tube using the symmetrical deflection magnetic field.

As can be seen from FIG. 6, in the color picture tube of the present invention, both side beams are made more circular and the tilt of the beam is small.

 This tendency appears over the entire screen.

In the color picture tube having the above-described structure, as shown in FIG. 8, the red, green, and blue three-color beams are horizontally separated from each other by a predetermined amount Δ. If the image is displayed as it is, the image of each color of red (R), green (G), and blue (B) is color-shifted by the above-mentioned Δ. This color shift can be easily matched with a certain delay with respect to the signal applied to the electron gun.

That is, when performing white display with a conventional color picture tube,
In the color picture tube of the present invention, the G electron gun is delayed by a predetermined time τ and the B electron gun is delayed by 2τ, while the transfer signals are simultaneously applied to the R, G, and B electron guns. This delay time τ is determined by τ = C · Δ / _H H. (FIG. 9) Here, H is the width of the screen, _H is the horizontal deflection frequency, and C is a constant determined by overscan or the like.

〔The invention's effect〕

The present invention realizes a screen in which the distortion of the electron beam spot is reduced over the entire screen by the above-described configuration and operation, and a bright high-resolution color picture tube device can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a color picture tube device of the present invention, and FIG.
FIG. 3 is a diagram for explaining the shape of the horizontal deflection magnetic field of the deflection device according to the present invention, FIG. 3 is a diagram showing the shape of the electron beam spot,
FIG. 4 is a diagram for explaining the shape of the vertical deflection magnetic field of the present invention, FIG. 5 is a diagram for explaining the state of the current applied to the vertical deflection coil of the present invention, and FIGS. 6 and 7 are electron beams. FIG. 8 is a diagram for explaining the shape of the spot, FIG. 8 is a diagram for explaining the deviation amount Δ of the three electron beams on the screen, and FIG. 9 is a diagram for explaining the delay time τ of the signal transferred to the three electron beams. 1 ... Face plate, 2 ... Funnel, 3 ... Neck, 5 ... Phosphor screen, 6 ... Shadow mask, 7 ... Electron gun

Claims (1)

(57) [Claims] 1. A neck in which three electron guns are horizontally installed inline, and a red, green, and blue neck 3 connected to the neck through a funnel and struck by an electron beam emitted from the electron gun to the inner surface. A face plate having a phosphor surface on which phosphor layers emitting light of different colors are regularly formed and deposited, and a large number of apertures arranged close to the face plate to selectively project the electron beam onto the phosphor layer. A color picture tube having a shadow mask having an outer wall and a deflection device which is mounted on the outer wall of the funnel and generates a horizontal deflection magnetic field for horizontally deflecting an electron beam emitted from the electron gun and a vertical deflection magnetic field for vertically deflecting the electron beam. In the apparatus, the three electron beams emitted from the electron gun are substantially parallel to each other, the horizontal deflection magnetic field forms a substantially uniform magnetic field distribution, and the vertical deflection magnetic field is generated. Is generated by applying different currents to a pair of coils arranged on the upper side and the lower side, and the shape of the magnetic field is vertically asymmetrical with respect to the horizontal plane including the color picture tube axis and in the vertical direction including the color picture tube axis. A color picture tube device comprising a deflection magnetic field symmetrical to the plane.