MXPA99003548A - Catodi rays tube - Google Patents

Abstract

A cathode ray tube that includes a rectangular panel in which a fluorescent screen is formed, a neck in which an electron gun assembly emits three electron beams and a funnel. The funnel which is comprised of a body portion and a cone portion wherein a contour of the cross section of the cone portion is a non-circular shape and the perpendicular distance from the axis of the tube to the contour occurs in the direction of a substantially diagonal, which makes an angle 0ï with respect to the horizontal axis according to the following inequality 0 - [4.3+ (S / 3.8)] < 0ï < 0 + [4.3+ (S / 3.8)] where 0 is an angle in degrees, the diagonal of the face panel makes with respect to the horizontal axis, S is the distance in mm between the electron centers passing the holes of the assembly of the electron gun

Description

CATHODE RAYS TUBE DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube (CRT), and more particularly, to a cathode ray tube capable of reducing the power consumption and preventing the magnetic fields of electromagnetic deflection from the escape to the outside of the cathode ray tube. A CRT is a device for displaying an image on a screen by electron beams of electromagnetic deflection horizontally and vertically generated from an electron gun and landing deflected electron beams on the phosphor layers formed on the screen. The electromagnetic deflection of the electron beam is controlled by an electromagnetic deflection gasket mounted on an outer surface of a CRT funnel and which forms horizontal and vertical magnetic fields. CRTs are generally used for color televisions (TVs), monitors and high definition televisions (HDTV) and with the increased use of CRTs there is a need to reduce the length of CRTs to increase brightness and image display and to reduce the size of the final products, as well as TVs, monitors and HDTVs. When they reduce the length of the CRT, the electron beams must be deflected by wide angles, and the frequency of electromagnetic deflection and the supply of Current to the electromagnetic deflection board must be increased by wide angle deflections to the electron beams. Like the electromagnetic deflection frequency and the current increase, the magnetic field of electromagnetic deflection tends to escape to the outside of the cathode ray tube and increase the power consumption. To reduce the magnetic field leakage, a compensating coil is generally mounted with the electromagnetic deflection joint. When, however, the compensation coil is used, the power consumption and the cathode ray tube is increased further. Alternatively, to reduce the electromagnetic deflection power and the magnetic field leak at the same time, it is conventionally preferable to reduce the neck diameter of the cathode ray tube and the outer diameter of the funnel near the neck side from which the electromagnetic deflection joint it is mounted, so the electromagnetic deflection field acts efficiently on the electron beams. However, when the diameter of the neck is simply reduced, there are disadvantages that the resolution of the image deteriorates due to the reduced diameter of the electron gun, and the external electron beams are suitable for bombarding the inner wall of the funnel, this way it turns out that the beams of Bombed electrons are not landed properly in the phosphor layer of the screen. To solve these problems, US Pat. No. 3,731,129 discloses a funnel having a wider peripheral portion sealed to the periphery of the panel and an electromagnetic deflection portion whose cross sectional configuration varies gradually from a rectangular shape substantially similar to that of the image. rectangular produced in the panel to a circular shape. Therefore, the vertical and horizontal coils of the electromagnetic deflection joint are located closely to the passage of the electron beams, and deflects the electron beams with reduced electromagnetic deflection power and without bombarding the electron beams to the inner wall of the electron beam. funnel. However, if the funnel has a rectangular cross-section it is designated without considering precisely the passage of the electron beams, the electromagnetic deflection magnetic fields generated by the electromagnetic deflection joint can not effectively deflect the electron beams, and the power consumption and electromagnetic deflection magnetic field leakage can not be minimized. To overcome the defect, the Japanese patent open to the public Pyung 9-320492 describes the funnel, whose The cross section of the outer surface to the neck side is changed from a circular shape to a non-circular shape which has a maximum diameter along a direction (diagonal direction) different from the horizontal axis and the vertical axis. The angle between the diagonal direction and the horizontal axis is changed according to the distance of the electron gun. The Japanese patent discloses that the CRT has the funnel that can reduce the electromagnetic deflection power and the magnetic field leakage by mounting the electromagnetic deflection joint to the position less close to the passage of the electron beams. However, the outer shape of the funnel in which the electromagnetic deflection joint is mounted, is designated without considering precisely the passages of the electron beams and the S value (ie a distance between the holes through the electron gun through of which the electron beams pass) and whereby the convergence and the focused characteristics of the electron beams are changed. Therefore, the power of electromagnetic deflection and magnetic field leakage of electromagnetic deflection can not be effectively minimized. Accordingly, the present invention is directed to a cathode ray tube which evidences substantially one or more of the problems due to the limitations and disadvantages of the related art. It is an object of the present invention to provide a cathode ray tube capable of minimizing the power consumption and preventing magnetic fields of electromagnetic deflection from the exhaust to the outside of the cathode ray tube. Another object of the present invention is to provide a cathode ray tube having a funnel whose outer surface is designated similar to the passage of the electron beams. A further object of the present invention is to provide a cathode ray tube suitable particularly for the flat panel cathode ray tube. To achieve this and other advantages, the cathode ray tube includes a rectangular panel in which a fluorescent screen is formed, a neck in which an assembly of the electron gun to emit three electron beams is arranged and a funnel. The funnel that is comprised of a body portion and a cone portion wherein a cross-sectional contour of the cone portion is in a non-circular shape and the perpendicular distance from the tube axis to the contour causes in the direction of a diagonal substantially which makes an angle? ' with regarding the horizontal axis according to the following? =. { 4.3+ (S / 3.8)} < ? ' < ? + { 4.3-r (S + 3.8)} where ? is the angle in degrees of the diagonal that the face panel makes with respect to the horizontal axis; S is the distance in mm between the electron centers that pass the holes of the assembled electron gun. The objects and other advantages of the invention will be realized and obtained by means of the structure indicated particularly in the written description and claims, as well as the attached drawings. It will also be understood that both of the foregoing general description and the following detailed description are exemplified and explained and are intended to provide a further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification, illustrate a particular embodiment of the invention and, together with the description, serve to explain the principles of the invention. In the drawings: Figure 1 is a perspective view in partial section of a cathode ray tube according to an embodiment of the present invention; Figure 2 is a perspective view of a cathode ray tube according to an embodiment of the present invention; Figure 3 is a graph to illustrate the shape of the cone part of a funnel according to an embodiment of the present invention; and Figure 4 is a partial sectional view of a funnel-like part according to an embodiment of the present invention. Preferred embodiments of the present invention should be described with reference to the accompanying drawings. As shown in Figures 1 and 2, a CRT is a casting development having a substantially rectangular face panel 3, a funnel 7 and a cylindrical neck 11. The face panel 3 has a phosphor layer covered on its inner surface 1. It also has a default aspect ratio. An electromagnetic deflection joint 5 is mounted on a portion of the funnel 7 near the neck 11 and an assembled electron gun 9 for emitting 3 electron beams that are arranged on the neck 11. The three electron beams emitted from the cannon assembly of electrons 9 are deflected horizontally and vertically by the vertical and horizontal magnetic fields generated by the deflection joint electromagnetic 5 and pass openings 13a in a shadow mask shown on the inner surface of the face panel 3 before hitting the phosphor layer which as a result, emits light of different colors depending on the phosphor material used. The funnel 7 is comprised of two distinct anterior portions, a cone portion 70b and a body portion 70c, which are contiguously formed. The electromagnetic deflection joint 5 is mounted on the cone portion 70b. And the present invention consists of the particular dimensional shapes of the cone portion 70b as described in the following. The cone portion 70b has a circular cross section of the point 70a where the cone portion is connected contiguously to the neck portion. The cross-sectional shape of the cone, however, changes gradually from the circular to the non-circular form as they are taken towards the funnel body. When the CRT is seen directly behind, the perpendicular distance of the central axis of the tube to the contour of the cross section is larger in diagonal direction substantially due to the cross sections, they should look more like a rectangle that like this one closer to the funnel body . A cone portion that has rectangular cross sections gradually has an advantage of attracting fields magnetic electromagnetic deflection generated from the electromagnetic deflection joint 5 closest to the passage of the electron beam. Figure 3 illustrates overlapping cross sections, marked by "A" and "B" of the cone portion at the point 70a where the cone portion starts and at the point where the cone portion ends respectively. inventively, the cone portion 70b is designated in such a way that the maximum distance from the tube axis to the contour of the cross section occurs in a substantially diagonal direction, here the tube axis is on an axis which passes to the center of the face 3 and the neck 11. More specifically the cone portion 70b can be defined by the following, which represents an angle? ' the diagonal substantially of the non-circular cross section made with respect to the horizontal axis.? - { 4.3+ (S / 3.8).}. <? ' <? + { 4.3+ (S / 3.8).} where? is the angle in degrees of the diagonal of the face panel made with respect to the horizontal axis, S is the distance in mm between the electron centers that passes the holes of the electron guns Figure 4 shows a cross-sectional view of a cone portion 70b in the first quadrant-in accordance with the present invention.

Cross section can be considered as having three curves connected in series. The first curvature C / Al represents the contour side and the second curvature C / As represents the upper part of the contour. The third C / Ad curvature is located between the first and second curvatures as illustrated in Figure 1. More particularly, the third curvature should be presented within the angle ?? ' between ?- . { 4.3 + S / 3.8)} and? +. { 4.3+ (S / 3.8)} . - The experiments shown, with such cone portion as configured in the above, the electromagnetic deflection joint 5 can become closer to the passage of the electron beams that result in the efficient beam of electromagnetic deflection so that the consumption of Electromagnetic deflection power is reduced to a minimum. The electromagnetic deflection power consumption of the CRTs with various configurations of the cone portion 70b is measured and the results are shown in the following table for a CRT where the aspect ratio is 4: 3,? 36.87 °, and S 5.6mm. [Table] As shown in the Table, the substantially diagonal axis of the cross section of the cone portion 70b is located within ±. { 4.3+ (S / 3.8)} to the angle? diagonal of the face panel, the power consumption of electromagnetic deflection is reduced. So far the description has been made as the outer surface of the funnel, more particularly the cone portion 70b. However, since the funnel of a CRT has a certain thickness, the inner surface of the cone portion preferably has a similar configuration. For the words of the inner contour of the cross section of the cone portion 70b it also gradually changes from a circular in the neck to a circular or rectangular substantially, to be specific, such that the maximum substance from the tube axis to the contour internal cross section occurs in a substantially diagonal direction. It will be apparent to those skilled in the art that various modifications and variations should be made in the present invention, without departing from the spirit and scope of the invention. This, intends that the present invention cover the modifications and variations of this invention with the condition that they come within the scope of the appended claims and their equivalents. This application is based on application No. 98-41356 filed in the Office of Korean Industrial Property on October 1, 1998, the content of which is incorporated herein for reference.

Claims (3)

1. CLAIMS 1. A cathode ray tube characterized in that it comprises: a face panel with a fluorescent screen; a neck in which an electron gun is arranged assembled; and a funnel which is comprised of a body portion and a cone portion wherein a contour of the cross section of the cone portion is in a non-circular shape and the perpendicular distance from the tube axis to the contour occurs in the diagonal direction substantially which makes an angle? ' with respect to the horizontal axis according to the following inequality? -. { 4.3+ (S / 3.8)} < ? ' < ? +. { 4.3+ (S / 3.8)} where ? is the angle in degrees, the diagonal of the face panel is made with respect to the horizontal axis; S is the distance in mm between the electron centers that passes the holes in the electron gun assembly.
2. 2. The cathode ray tube according to claim 1, characterized in that the contour is in the external contour of the cross section.
3. 3. The cathode ray tube according to claim 2, characterized in that the contour is in the internal contour of the cross section.