JP3053841B2 - Deflection device for in-line color CRT - Google Patents

Description

Description: Object of the Invention (Field of Industrial Application) The present invention relates to a deflecting device for an in-line type color cathode ray tube, and more particularly to a deflecting device for an in-line type color cathode ray tube suitable for a high-resolution color display tube.

(Prior Art) Generally, as shown in FIG.
Three electron beams (2B), (2
G) and (2R) are deflected by the horizontal and vertical deflection magnetic fields of a deflection yoke (4) mounted outside the envelope (3), and the phosphor screen (6) is leveled via a shadow mask (5). The phosphor screen (6) is formed so as to display a color image by vertical scanning.

In particular, for an in-line type color cathode-ray tube that emits three electron beams consisting of a center beam and a pair of side beams arranged in parallel on the same horizontal plane from an electron gun, a non-uniform type in which a horizontal deflection magnetic field is a pincushion type and a vertical deflection magnetic field is a barrel type. A self-convergence type deflection yoke that generates a magnetic field is generally used.

When such a deflection yoke is combined with an in-line type color cathode ray tube, a pair of side beam rasters (9B), (9B), (9B), (8B), as shown in FIG. 9R) can be matched. However, it is difficult to match the center beam raster (9G) with the pair of side beam rasters (9B) and (9R), and the horizontal (x-axis) end and vertical (y-axis) end of the screen (8). Coma aberration indicated by HCR and VCR occurs.
For example, in the case of a 14-inch 90-degree deflecting color picture tube, the HCR is about 0.5 mm and the VCR is about 1.0 to 2.0 mm. A field controller made of a magnetic material that is magnetically coupled to the rear leakage magnetic field is attached, and the correction is made to an almost satisfactory level.

However, as shown in FIG. 8, when the HCR at the horizontal axis end of the screen (8) is optimally corrected, a pair of side beam rasters (9B) and (9R) are provided at the screen diagonal. On the other hand, a green droop HGD occurs in which the center beam raster (9G) is outside. Therefore, the correction that is actually performed is a compromise that sets the HCR at the horizontal axis end to 0.1 to 0.2 mm and the HGD at the screen diagonal to 0.
It is about 1-0.2mm.

Therefore, the misconvergence between the center beam raster (9G) and the pair of side beam rasters (9B) and (9R) in this in-line type color CRT is
0.2 to 0.4 mm, which is inappropriate for a high-resolution color display tube.

(Problems to be Solved by the Invention) As described above, the deflection yoke of the Seleph conversion type in which the horizontal deflection magnetic field is of the pincushion type and the vertical deflection magnetic field is of the barrel type is formed by arranging three electron beams in parallel on the same horizontal plane. When combined with an in-line type color picture tube, it is possible to match the pair of side beam rasters, but it is difficult to match the center beam raster and the pair of side beam rasters. And coma HCR and VCR occur at the vertical axis end.
In order to correct this coma aberration, a field controller made of a magnetic material that is magnetically coupled to a rear leakage magnetic field of a deflection yoke is used in a general color picture tube. However, when the HCR at the horizontal axis end of the screen is optimally corrected, a green droop HGD occurs in which the center beam raster is outside the pair of side beam rasters at the diagonal of the screen. However, it is inevitable to make a compensatory correction, and a high-resolution color display tube cannot be corrected until misconvergence is sufficiently satisfied.

The present invention has been made in view of the above-described problems, and has as its object to configure a deflection device that does not generate a green droop at a diagonal portion of a screen when an HCR at an end of a screen horizontal axis is optimized.

[Means for Solving the Problems] An in-line color cathode ray tube deflection including a deflection yoke having a horizontal deflection coil for generating a pincushion type horizontal deflection magnetic field and a vertical deflection coil for generating a barrel type vertical deflection magnetic field. In the apparatus, two sets of sub-coils that generate magnetic fields in the same and opposite directions corresponding to the pincushion type horizontal deflection magnetic field by supplying a horizontal deflection current flowing through a horizontal deflection coil are provided on the rear end side of the deflection yoke. A saturable core disposed and magnetically biased until immediately before saturation, and a pair of impedance coils connected in series to each of the two sets of subcoils and wound around the saturable core as a magnetic core; An impedance coil parallel circuit in which a pair of series circuits of Current obtained by rectifying the vertical deflection current flowing through the vertical deflection coil is provided with a saturable reactor comprising a magnetic coil supplied by rectifier circuit connected around the wound the vertical deflection coil to the saturable core.

(Operation) As described above, the impedance coil of the saturable reactor is connected in series to each of the two sets of subcoils, and the impedance coil parallel circuit in which the series circuit is connected in parallel is wound around the saturable core to form the vertical deflection coil. When connected to a magnetic coil to which a current obtained by rectifying the vertical deflection current flowing through the vertical deflection coil by the connected rectifier circuit is supplied, the impedance of the impedance coil can be changed in synchronization with the absolute value of the vertical signaling current. By changing the impedance of the impedance coil, the current flowing in one sub-coil and the current flowing in the other sub-coil can be changed differentially. As a result, a magnetic field in the same direction as the horizontal deflection magnetic field is generated in one sub-coil, and a magnetic field in the opposite direction to the horizontal deflection magnetic field is generated in the other sub-coil. That is, one sub-coil generates a main magnetic field, and the other sub-coil generates a bias magnetic field. Since the change in the intensity of the magnetic field generated by the two sets of sub-coils increases in the same direction as the horizontal deflection magnetic field with the increase in the absolute value of the vertical deflection current, the pair of sub-coils moves from the center of the screen toward the periphery in the vertical direction. The horizontal deflection of the side beam becomes stronger than the horizontal deflection of the center beam, so that the HCR at the horizontal axis end of the screen can be optimized and the green droop at the diagonal portion of the screen can be eliminated.

Hereinafter, the present invention will be described based on embodiments with reference to the drawings.

FIG. 1 shows a deflecting device for an in-line type color picture tube as one embodiment, and FIG. 2 shows a deflecting yoke. This deflection device includes a deflection yoke (20), two sets of sub-coils (21) and (22), a rectifier circuit (23), and a saturable reactor (24). Its deflection yoke (20)
Is a saddle-type horizontal coil (26) placed vertically symmetrically inside the mold (25), and a toroidal coil wound vertically around the core (27) and placed vertically symmetrically outside the mold (25). A vertical deflection coil (28) for generating a pincushion-type horizontal deflection magnetic field and a barrel-type vertical deflection magnetic field, respectively.

The two sets of sub-coils (21) and (22) are a pair of U-shaped cores (30) arranged symmetrically on the rear end of the deflection yoke (20) with a vertical axis (Y axis) interposed therebetween. And a pair of series coils (31) wound around the pair of cores (30).
a), (31b) and (32a), (32b), which are symmetrical. Each sub coil (21), (2
2) is connected to a horizontal deflection coil (26) via an impedance coil of a saturable reactor (24), which will be described later, and is supplied with a horizontal deflection current flowing through the horizontal deflection coil (26). On the rear end side, one sub-coil (21) generates a pincushion-type magnetic field in the same direction as the pincushion-type horizontal deflection magnetic field of the horizontal deflection coil (26), and the other subcoil (22) A pincushion-type magnetic field is generated.

The saturable reactor (24) includes a pair of cylindrical saturable cores (35a) and (35b) and one of the two sub-coils (21) and (22). An impedance coil (36a) connected in series and wound around one saturable core (35a) as a magnetic core, and another saturable core (35b) connected in series to the other sub-coil (22). And an impedance coil (36b) wound therearound. These impedance coils (36
a) and (36b) are connected in parallel, and are connected in series with two opposite polarities to reduce the change in inductance due to the effects of the currents I21 and I22 flowing through the two sets of sub-coils (21) and (22). (37a), (37b) and (37c), (37d). Each of the saturable cores (35a) and (35b) has a configuration in which magnets (38) are arranged at both ends so as to operate in a non-linear region, and are magnetically biased by the magnets (38).

Further, the saturable reactor (24) has a magnetic coil (39) wound around the saturable cores (35a) and (35b). This magnetic coil (39) consists of four rectifiers (40)
Are connected in a fridge shape and are parallel to a rectifier circuit (23) for full-wave rectification of the sawtooth vertical deflection current flowing in the vertical deflection coil (28) and a variable resistor (41) for adjusting the current flowing in the magnetic coil (39). Connected to the vertical deflection coil (28) via the rectifier circuit (23) and the variable resistor (41).

Next, the operation of the deflection device will be described. Now, assuming that the electron beam is deflected upward, when a vertical deflection current IV in the direction of arrow (42) flows through the vertical deflection coil (28), the magnetic coil (39) is subjected to full-wave rectification by the rectifier circuit (23). The vertical deflection current adjusted by the variable resistor (41) flows. As a result, saturable cores (35a), (35b)
A magnetic flux φV in the direction of the arrow (43) is generated therein, and the magnetic flux φ in the directions of the arrows (44a) and (44b) is simultaneously applied to the impedance coils (36a) and (36b) connected to the horizontal deflection coil (26).
When L occurs, the impedance coil (36a)
The magnetic flux in the saturable core (35a) is φV + φL The magnetic flux in the saturable core (35b) of the impedance coil (36b) is φV−φL, and the inductance of the impedance coil (36a) is relatively small. Impedance coil (36
The inductance of b) increases. Also, when the electron beam is deflected downward, the magnetic coil (39) receives a vertical deflection current, which has been subjected to full-wave rectification by the rectifier circuit (23) and adjusted by the variable resistor (41), and has the impedance coil (36a). The inductances of () and (36b) change in the same manner as in the case of upward deflection.

Therefore, according to this deflection device, two sets of sub-coils (21) and (22) are synchronized with the scanning cycle in the vertical direction of the screen.
The currents I21., I22 flowing through are as shown by curves (46a), (46b) shown in FIGS. 3 (a) and 3 (b), respectively. As a result, when the electron beams (2B), (2G), and (2R) are deflected to the left of the screen, a pincushion-type magnetic field (47a) shown in FIG. A pincushion-shaped magnetic field (47b) shown in (b) is generated in the other subcoil (22). Further, when the electron beam is deflected rightward on the screen, a pincushion-type magnetic field is generated in the opposite direction to the above-described leftward deflection, and the combined pincushion obtained by the two sets of sub-coils (21) and (22) As shown in FIG. 5, the strength Bab of the shaped magnetic field is strong at the upper and lower ends of the screen, becomes zero at the center of the screen, and the direction of the pincushion magnetic field is the direction of the pincushion horizontal magnetic field generated by the horizontal deflection coil (26). This is the same as the direction of the deflection magnetic field. Therefore, when deflecting the electron beam to the diagonal part of the screen, two sets of sub-coils (2
The pincushion-type magnetic field strength Bab obtained by (1) and (22) can be increased, thereby eliminating the green droop that has occurred at the screen diagonal when the HCR at the horizontal axis end of the screen has been optimally corrected. can do.

That is, in the deflecting device of this example, the intensity Bab of the pincushion magnetic field obtained by the two sets of sub-coils (21) and (22) can be dynamically changed in synchronization with the scanning cycle in the vertical direction of the screen, This makes it possible to optimally correct the HCR at the horizontal axis end of the screen and optimally correct the green droop at the diagonal part of the screen. In addition, the operating point of the saturable reactor (24) can be easily adjusted by the variable resistor (41) connected in parallel with the magnetic coil (39), and the green droop can be easily corrected.

[Effect of the Invention] A horizontal deflection current supplied to the horizontal deflection coil is supplied to the rear end of a deflection yoke having a horizontal deflection coil for generating a pincushion type horizontal deflection magnetic field and a vertical deflection coil for generating a barrel type vertical deflection magnetic field. And two sets of sub-coils for generating magnetic fields in the same and opposite directions corresponding to the pincushion-type horizontal deflection magnetic field are arranged in series with each of the saturable core and the two sets of sub-coils magnetically biased until just before saturation. An impedance coil parallel circuit having a pair of impedance coils connected to each other and wound around the saturable core as a magnetic core, wherein a pair of series circuits of the impedance coil and the sub coil are connected in parallel; and Vertical deflection flowing through the vertical deflection coil by a rectifier circuit wound around a core and connected to the vertical deflection coil By providing a saturable reactor consisting of a magnetic coil to which a rectified current is supplied, the impedance of a pair of impedance coils can be changed in synchronization with the absolute value of the vertical deflection current. The current flowing in the sub-coil and the current flowing in the other sub-coil are changed differentially, whereby a magnetic field in the same direction as the horizontal deflection magnetic field is applied to one sub-coil, and a magnetic field in the opposite direction to the horizontal deflection magnetic field is applied to the other sub-coil. A magnetic field can be generated. That is, one of the sub-coils generates a main magnetic field, and the other sub-coil generates a bias magnetic field. A change in the strength of the magnetic field generated by the two sets of sub-coils is accompanied by an increase in the absolute value of the vertical deflection current. The horizontal deflection of the pair of side beams increases with respect to the horizontal deflection of the center beam from the center of the screen toward the periphery in the vertical direction. Green droop at the corners can be eliminated, and an in-line type color picture tube having good conversion characteristics can be realized.

[Brief description of the drawings]

1 to 5 are explanatory views of an embodiment of the present invention.
FIG. 1 is a circuit diagram showing a configuration of an in-line type color picture tube deflecting device according to an embodiment, FIG. 2 is a perspective view showing the configuration of the deflection yoke, and FIGS. 3 (a) and 3 (b) each show two sets. FIG. 4 is a diagram showing a relationship between currents flowing through the sub-coils of FIG.
Figures (a) and (b) show the directions of a pincushion-type magnetic field generated by two sets of subcoils, respectively, and Figure 5 shows the strength of a pincushion-type magnetic field obtained by combining two sets of subcoils. 6, FIG. 6 is a view showing the structure of a color picture tube, FIG. 7 is an explanatory diagram of coma aberration occurring in an in-line color picture tube, and FIG. 8 is a relation between coma aberration HCR and green droop in the in-line color picture tube. FIG. 20… Deflecting yoke, 21… Sub coil, 22… Sub coil, 23… Rectifier circuit, 24… Saturable reactor, 26 …… Horizontal deflection coil, 28 …… Vertical deflection coil, 30 …… Core, 31a, 31b …… A pair of series coils, 32a, 32b …… A pair of series coils, 35a, 35b …… A pair of saturable cores, 36a, 36b …… A pair of impedance coils, 37a-37d …… Coil, 38… ... magnet, 39 ... magnetic coil, 40 ... rectifier, 41 ... variable resistance.

Claims (1)

(57) [Claims] A deflection yoke having a horizontal deflection coil for generating a pincushion-type horizontal deflection magnetic field and a vertical deflection coil for generating a barrel-type vertical deflection magnetic field; Two sets of sub-coils that generate magnetic fields in the same and opposite directions as the pincushion-type horizontal deflection magnetic field by supplying a horizontal deflection current flowing through the coil; a saturable core magnetically biased until just before saturation; An impedance coil parallel circuit having a pair of impedance coils connected in series to each other and wound around the saturable core as a magnetic core, and a pair of series circuits of the impedance coil and the sub coil connected in parallel; And a rectifier circuit wound around the saturable core and connected to the vertical deflection coil. The rectifying circuit comprises a magnetic coil to which a current obtained by rectifying a vertical deflection current is supplied, and a current rectified by the rectifying circuit and supplied to the magnetic coil causes a winding portion of one impedance coil of the saturable core and the other impedance And a saturable reactor that generates magnetic fluxes of opposite phases to the winding part of the coil and changes the current flowing through the two sets of sub-coils differentially in synchronization with the vertical deflection current by the magnetic fluxes of the opposite phases. A deflector for an in-line type color cathode ray tube, comprising: