JPS5885258A - Deflection york for projection tube - Google Patents

Abstract

PURPOSE:To remove the horizontal trapezoidal distortion or the like of a projected image by means of a simple constitution, without increasing consumption electric power, by enabling the raster distortion formed on a projection screen to be cancelled by making the distribution of the deflected magnetic field of an electron beam asymmetrical relative to the axis of a projection tube by means of a deflecting coil. CONSTITUTION:A vertically deflecting coil 13 consists of a pair of coils 131 and 132, which are wound into saddle-like form and face to one another being located on both sides of a vertical surface 18 including a tube axis 16. Here, the numbers of turns of the coils 131 and 132 are equal. However, when the diameters of the fringed parts 151 and 152 on the fluorescent screen side of the coils 131 and 132, respectively, are represented by R1 and R2, the relationship of R1<R2 is satisfied. Thus, the diameters of the fringed parts 151 and 152 are differed by making R1 smaller and R2 larger than the diameter of a fringed part which can realize a raster with a normal fineness ratio. As a result, a desired distortion can be given to a raster by means of a simple constitution, consumption electric power is reduced, and a deflection york with a stable operation can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deflection field of a projection tube suitable for a projection television apparatus.

As the demand for the image reproduction surface of the television receiver's image reproduction screen became stronger and the image was reproduced on the fluorescent surface of the cathode ray tube, nine images were reproduced on the fluorescent surface of the cathode ray tube. 2. Description of the Related Art So-called projection preview devices (hereinafter referred to as PTVs), which obtain large-sized television images by projecting onto a screen using a projection optical system such as a reflecting mirror, have become widely used.

As shown in Figure 1, this PTV has a cathode blue tube (hereinafter referred to as a projection tube) 1B that projects the red light.
1 green light gIt - projection y1G, evening light*'e projection tube 1B, lenses 2R, 2G.

2B and screen 4, projection tube 1R2iG,
Each color light projected by lB is projected by lens 2R.

The image is enlarged by 2G and 2B, and one image is projected onto the screen 4 to be enlarged and projected into nine color images.

Such a PTV has one projection tube on the center line (hereinafter referred to as the vertical center line) 3G perpendicular to the screen 4,
For example, projection tube IQ? and the other two projection tubes 1R, 1
B is placed on the center lines 3R, 3B at an equiangular angle θ in the horizontal direction with respect to the vertical center line 3q.By the way, the rasters formed on each projection tube 1R, 1G, 1B are rectangles with exact specified ratios. If so, the raster projected onto the screen 4 by the projection tube 1G located on the vertical center line 3G will be a rectangle with an exact specified ratio, but the raster projected onto the screen 4 by the projection tubes IR and IB will be Since the two stars on the tube will be projected diagonally onto the screen 4, they will not be rectangular but will be distorted.

That is, as shown in FIG. 2, the raster 5GH projected on the screen 4 by the projection tube 1GK becomes a rectangle symmetrical to the X and Y axes, but the raster 5R by the projection tube 1R
is compressed on the right side of the Y axis and expanded on the left side, forming a trapezoid symmetrical to the Y axis.
l-1, conversely, Y expanded on the right side of the Y axis and compressed on the left side
It becomes a trapezoid that is symmetrical about the axis.

Such changes in the horizontal expansion and contraction of the projection rasters 5R and 5G (hereinafter referred to as changes in horizontal linearity) and trapezoidal distortion (hereinafter referred to as horizontal trapezoidal distortion) are caused by the projection tubes 1R and 1B.
In order to project onto the screen 4 obliquely by an angle θ with respect to the vertical center line 3G on the upper raster', the distance between each point of the raster of the projection tube and each point on the screen where they are projected is These changes in horizontal linearity and raster distortion on the screen 4 due to horizontal trapezoidal distortion are caused by differences in each projection tube 1R.

1(j, 1BK-by each color light gII meeting and power j-i1
Naturally, when displaying my own image, color shift, ie, misconvergence, occurs. To my friend, this pageant (−
For those who want to correct 0 misconvergence who need a means to correct the 0 misconvergence, taking the projection tube 1R as an example, the raster 5R on the screen 4 is as shown in FIG. Therefore, it is sufficient to generate a raster 6 on the projection tube 1R, which has a distortion opposite to that of the raster 5R as shown in FIG.

That is, in FIG. 3, straight lines 5a, 5c, and 5b.

The raster 6 surrounded by 6d is distorted into a trapezoidal shape to offset the horizontal trapezoidal distortion of Lascu 5R shown in Figure 2, the right side of the Y axis of Mayu and Lascuro is extended horizontally, and the left side is Compress horizontally and make each horizontal length J1
Raster 5 shown in Fig. 2 is different from r12.
This method is conventionally used to offset all changes in horizontal linearity, as shown in Figure 11!4 (a), horizontal linearity as shown in Figure 11! Direct deflection coil 12.13? The projection tube 1 having the deflection eye 8 is further provided with an auxiliary deflection yoke 9t, and the electron beam 11t-1 from the electron gun 10 is deflected horizontally and vertically by the deflection yoke 8 in the normal manner. There is a type of yoke 9 that deflects the beam in a predetermined direction to obtain a raster with distortion as shown in FIG.

But according to this conventional method, what about the auxiliary deflection yoke and its electrical circuit? 6b111, which not only complicates the configuration and increases costs, but also increases power consumption due to the flow of correction current and unstable operation due to electrical fluctuations. ,
Therefore, until now, it has not been possible to obtain a projection television device with good image quality and low power consumption at a low cost.An object of the present invention is to eliminate the drawbacks of the above-mentioned prior art, and to produce a raster image with a simple configuration. The object of the present invention is to provide a projection tube deflection yoke t'' that can produce the desired distortion, reduce power consumption, and be inexpensive to operate.

In order to achieve this object, the present invention is characterized in that the deflection coil is entirely wound in a circular shape, and the deflection coil makes the deflection magnetic field distribution of the electron beam asymmetrical with respect to the tube axis of the projection tube.

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

FIG. 5 is a perspective view showing an embodiment of the deflection yoke of the projection tube according to the present invention, in which 8 is a deflection yoke, 12 is a horizontal deflection coil, 13 is a vertical deflection coil, 14 is a core, 15x,
15z is a fringe portion of the 1iiffi deflection coil, and 16 is the central axis of the deflection yoke, that is, the tube axis of the projection tube.

FIG. 6 is a structural diagram of one embodiment of the vertical deflection coil viewed along the tube axis 16 from the fluorescent surface side of the projection tube.

In FIGS. 5 and 6, the vertical deflection coil 13 is a pair of two coils 13t and 13t wound in a hollow shape,
A perpendicular surface 18' including the tube axis 16 is provided as an opposing surface. Each coil 131, 131 has the same number of coil windings, but if the diameter of the fringe portion 151.15g0 on the fluorescent surface side is R1* R*, then R1<R, and the raster with the normal aspect ratio. (hereinafter referred to as regular raster)
By increasing 1, the fringe portions 151, 151
have different radii. Note that 13m-13b are coil portions (hereinafter referred to as
1T is the surface of the deflection coil 13 on the electron gun side.

With this structure, when a deflection current t is applied to the 7t coils 131 and 13, the electron beam is deflected in a predetermined direction by the magnetic fields of the respective fringes 515s and 15g, producing a trapezoidal raster on the fluorescent surface.

Next, the function of the vertical deflection coil 13 will be explained in detail with reference to FIGS. 7 and 8.

FIG. IN7 is an explanatory diagram for explaining the action of the vertical deflection coil in FIG. 6, and parts corresponding to those in FIG. 6 are given the same reference numerals.

Now, assuming that a deflection current of 11 is applied to each coil 131, 131, an electron beam traveling from the electron gun (not shown) along the tube axis 16 toward us from the back side of the paper is transmitted to each coil 13t. , 132 conduct groups 13m, 13
It is deflected in the direction of arrow 19 by the magnetic field generated by bK and vertically scans the tube above the fluorescent surface. At the same time, this electron beam is deflected in the direction of arrow B by the magnetic field generated by the conductor group of the horizontal deflection coil 12 (FIG. 5), and horizontally scans the fluorescent surface.

Based on this method, point a1 * aj l R31R in Figure 8
A regular raster of rectangles indicated by dotted lines with 4t-vertices will be obtained.

By the way, due to the current flowing through the fringe portions 151 and 151 of the coils 131 and 13g, a current flows in the vicinity of the plane including the fringe portions 151-15s' perpendicular to the tube axis 16 (hereinafter referred to as the fringe portion surface) in a direction perpendicular to the fringe portion surface. Therefore, a magnetic field is generated parallel to the tube axis 16, but the magnetic fields due to the fringe portion 151 and the edge of the fringe portion 15 have opposite directions and different strengths, and are asymmetrical with respect to the tube axis 16.

Therefore, considering the case where the electron beam scans the upper half of the raster, the direction of the deflection current flowing through each coil 131, 131 is the direction of the arrow 20, and the direction of the deflection current flowing through the fringe portion 15 is
The direction of the magnetic field due to the fringe portion 15 is from the back to the front of the paper, and the direction of the magnetic field due to the fringe portion 15 is in the opposite direction.

The conductor group 13a of each coil 131.131
, 13b causes the electron beam to be deflected (
However, when the horizontal deflection is also performed at the same time), when the point P on the fringe part surface is reached, the Lorentz force F! due to the magnetic field B1 from the fringe part 151! receive. Assuming that it is an alternating electron beam that reaches this point P or reaches the upper right corner of the raster on the fluorescent surface (point a1 in Figure 8), the radius R1 of the fringe m1st of the coil 131 will produce a normal rask. If it is a radius, the constant electron beam that passes the point Pt- reaches the raster point Ji1 (FIG. 8) while receiving the Lorentz force Fst due to the magnetic field B1, but the fringe portion 151
Since the radius R1 of 9 is also set small to produce a regular Laskue, the strength of the magnetic field B1 due to the fringe 5151 increases, and the four-Lenz force F acting on the electron beam at point P increases. do. Therefore, the velocity vector V1 of the electron beam at point P rotates counterclockwise (hereinafter the same) with respect to the axis perpendicular to the plane of the paper at a larger rotation angle than when generating a regular raster, and The electron beam that should reach a1 is located at point b to the upper left of this point.
It will be different from 1.

In this way, when the electron beam is scanning the upper right half of the Lascou, the electron beam is completely affected by the magnetic field generated by the fringe part 151, and the velocity vector of the electron beam rotates counterclockwise. However, as the electron beam scans the fluorescent surface, horizontal,
(ii) Since the magnitude of the deflection current flowing through the direct deflection coil is changed, the strength of the magnetic field due to the fringe section 151 and the velocity vector of the electron beam vary depending on the position of the electron beam when it crosses the fringe section surface. For this reason, the counterclockwise rotation angle of the velocity vector of the electron beam is different.

In summary, in FIG. 8, since the vertical deflection current is zero on the X-axis, the velocity vector of the electron beam does not rotate due to the magnetic field of the fringe section 151. Also, on the Y-axis, the horizontal deflection current R is Since it is zero, the velocity vector of the electron beam does not have a component in the Fix axis direction, and the fringe portion 15
Due to the rotation of the velocity vector by the magnetic field of 1, the electron beam does not reach the Y-axis of the fluorescent surface, but reaches the lower left of it.0th order K, when the electron beam scans the upper left half of the fluorescent surface. The action of the fringe portion 15g of the coil 132 will be explained.

The radius R8 of the edge of the fringe portion 15 also increases the radius of the fringe portion when generating a regular raster. This means that the strength of the magnetic field due to the fringe part when a regular Lascou is produced is also small.

When the electron beam is scanning the upper left half of the fluorescent surface, the deflection current I5 of the coil 132! is the direction of the arrow 20, and the direction of the magnetic field generated by the fringe portion 15 is from the front to the back of the page.The velocity vector Vl of the electron beam passing through the magnetic field of the O-fringe 515t is 131,131
Conduct group 13m.

Due to the action of the magnetic field B2 of the fringe portion 152, it is directed diagonally upward to the left with respect to the plane of the paper, but due to the action of the magnetic field B2 of the fringe portion 152, the edge rotates counterclockwise.

Therefore, considering the electron beam that has reached point Q on the fringe section surface, if the radius R of the fringe section 152 is set to produce a regular raster, then the velocity vector Vl of the electron beam that has reached point QK Assuming that the magnetic field BxK area due to the fringe portion 152 rotates counterclockwise and reaches a point aS (FIG. 8) at the upper left corner of the regular raster,
Since the radius of the fringe portion 152 is larger than the radius required to generate a regular raster, the strength of the magnetic field due to the fringe portion 152 is small, and the counterclockwise direction of the velocity vector v2 of the electron beam that has reached point Q is The rotation angle of the direction becomes smaller.

For this reason, the position where the electron beam reaches the fluorescent surface is relatively to point b, which is to the lower left of area a2! becomes.

Contrary to the effect on the electron beam due to the magnetic field of the fringe portion 151 of the coil 131, the magnetic field of the 7-lunge 5152 of the coil 13+ causes the electron beam's speed vector v
2 rotates clockwise, but the rotation angle is smaller than that for producing a regular raster, and the Y axis,
The counterclockwise rotation angle decreases as the distance from the Y-axis increases, so in the Lascue region in the upper left half of the fluorescent surface, the Y-axis.

The further away from the Y-axis the position where the electron beam hits the fluorescent surface shifts toward the lower left to a greater extent than the position where the electron beam hits the fluorescent surface during regular two-star scanning.

When scanning the area below the fluorescent surface, the coil 13
Since the polarity of the deflection current flowing at s, 13 mK is reversed, the direction of the magnetic field due to the fringe section 151.15 iK is reversed, and as is clear from what has been explained so far, the normal The position where the electron beam hits the fluorescent surface is shifted to the lower left than in the case of two-star scanning, and in the lower left half region of the fluorescent surface, it is shifted to the upper left.

Therefore, the asymmetric fringe*1 of coil 13*-138
2 stars obtained by the magnetic field of 5x, 15 snow are:
The solid line with the vertex at point b1 l ba * bs e ba in Figure 8 is l! 1, the left and right boundaries 5c and 5d of the Rascou are curved to the right, and in this way above and below, a raster with a trapezoidal distortion t is obtained, but the border line It is clear from 5c and 5d that they curve in the upward and downward directions and include t-distortion, and this curvature distortion must be corrected. This correction is performed by creating an asymmetrical magnetic field by a group of conductors in the vertical deflection coil.

Next, this correction will be explained with reference to FIGS. 9 to #111.

In FIG. 9, facing ends 13'a, ? of conductors 13a, 13b of coils 131, 132 are shown. 3'b, a surface including these ends m 13'a = 13'b' and including the tube axis 16 (hereinafter referred to as conductor group 13a-
19 and 19' (referred to as opposing surfaces of 13b) are planes that intersect at the tube axis 16. That is, coils 131, '132
conductor groups 13a, 13bfl, and their opposing surfaces 1
9.19' is an angle β toward the vertical plane 18 including the tube axis 16t, respectively, toward the coil 131 whose fringe portion has a smaller radius.
〇The direction of the magnetic field lines due to the conductor group 13a113bK is -
In the direction perpendicular to the surface 18, that is, in the direction parallel to the horizontal plane 22, as described above, the conductor group 13m-1
When the winding angle of 3b is set, the lines of magnetic force due to the conductor group 13aK become relatively uniform, and the conductor lI'P13b
Kz magnetic field lines become relatively sparse.

The magnetic force ll1I at this time is #! It becomes as shown in Figure 10.

FIG. 10 shows the magnetic field lines due to the fundaduct group 13m = 13b K in a plane perpendicular to the tube axis 16 in FIG. ) When scanning above the horizontal line [22, as shown by the solid line, the magnetic force! 21 direction is curved upper left 9
When the electron beam scans below the horizontal center line of the fluorescent surface, the polarity of the vertical deflection current is reversed, so as shown by the dotted line below the horizontal surface 22, the magnetic force M 21
' direction is curved upper right. And curved upper left 9
, the upward right angle becomes smaller as it approaches the horizontal plane 22.

When an electron beam passes through such a magnetic field, the electron beam is directed in a direction perpendicular to the lines of magnetic force.

In this way, the electron beam is vertically deflected, but if the magnetic field lines 21 are curved upward to the left as described above,
The electron beam is directed perpendicularly to the upper right 9 with respect to the straight upward direction. Furthermore, if the magnetic lines of force 21' are curved upward to the right, the electron beam is perpendicular to the slightly right edge with respect to the vertical downward direction.

Therefore, the contour of the Lascue obtained by applying the magnetic field due to the conductor group 13a-13bK is as shown in FIG.
The upper and lower boundaries 5a and 5b are straight lines approaching each other in the left direction, but the left and right boundaries 116C and 6d are curved to the left to form nine curved lines, which are curved in the opposite direction to that shown in FIG.

Therefore, if a vertical deflection coil tube is formed using a coil pair having a conductor group and a fringe portion formed as described above, the curvature distortion in the left and right direction in FIGS. 8 and 11 cancels each other out, and as shown in FIG. ↓A Lascou with a trapezoidal distortion is obtained on the fluorescent surface, which is shown in Figure 2. Next, the horizontal trapezoidal distortion t of the projected image of the screen 4 (Figure 1) by the projection tube 1B
Can be corrected.

In FIG. 1, the horizontal trapezoidal distortion t for the projection tube 1B is corrected by the shape t1 of each vertical deflection coil.
It is clear that it would be better to do the opposite of the above.

Next, correction of changes in horizontal linearity will be explained. This correction is performed by the horizontal deflection coil 12 shown in the thirteenth factor.

In FIG. 13, the horizontal deflection coil 12 is vertically opposed and consists of a pair of coils 12s and 12g.
However, by determining the angle 11m% in the winding of the coil part (hereinafter referred to as the side conductor) that forms the magnetic field in the horizontal wound of the coil 121.12m, it is formed asymmetrically with respect to the -plane 18. .

In other words, the angle α1. α5t14, coil 12 side conductor 12b-xt 12b-
Angle α3 of the winding width of z. Different α4. However, angles α1 and α3 are equal, ! ! Friend, let α3 and α4 be equal.

FIG. 14 shows lines of magnetic force due to the side conductors of the horizontal deflection coil formed in this manner.

In the same figure, as mentioned above, the coil pair 121°122
From the tube axis 16 to the side; Rusk)
Angle r1 taking into account 12a-1, 12b-t and angle r taking side conductor 12a-in and 12b-it into account.
.

It is different from that.

Therefore, side conductor 12 a-1-12a-
12b-x.

The magnetic field lines 21' generated by 12b-z have a vertically curved shape curved to the left in the horizontal direction.

Now, if we assume that the electron beam scans to the right of the vertical line 18, the lines of magnetic force 21' will become as shown by solid lines, and the electron beam will be horizontally deflected by receiving a force psi perpendicular to the lines of magnetic force 21'. However, because the direction of the magnetic field lines 21' is curved, when the electron beam is above the fluorescent surface, it is deflected to the lower right, and when it is below, it is deflected upward to the wiping cloth, and the tube axis 16t - containing horizontal line 22
When it is above, it is deflected to the right.〇On the other hand, if the electron beam is to scan the vertical line 18 area left, the magnetic force 1!21' will be shown by the dotted line, and the electron beam will be deflected by the magnetic force i121'. Horizontal deflection is performed by receiving a vertical force Fs*, but contrary to the above, when the electron beam is above the fluorescent surface, it is deflected to the upper left, and when it is below, it is deflected to the lower left, and vice versa. When it is on the horizon 22, it is deflected to the left.

Note that when the electron beam is on the vertical line 1B, the horizontal deflection current is zero, so it is not horizontally deflected.

Therefore, the raster obtained on the fluorescent surface has a trapezoidal shape in the horizontal direction, as shown in FIG. Then, in the horizontal direction, the right side of Lascoux expands and the width becomes 11,
The left side of the 2 star is compressed and the width becomes 1□. These widths J, , J, are shown in 11. of Fig. 3. j! And #I
The amount of horizontal linearity change tube correction for the raster 5R in Figure 2 is 0. Formed as above, the raster appearing on the fluorescent surface is , the trapezoidal rask shown in FIG. 13 is distorted in the horizontal direction shown in FIG. 15, resulting in the raster shown in FIG. 3. Here, trapezoidal distortion occurs in the raster shown in Fig. 15 in the opposite direction to the raster shown in Fig. 12, but these trapezoidal distortions are combined to form the desired trapezoidal distortion shown in Fig. 3. do.

It is clear that the projection tube 1B in FIG. 1 must be formed to have a shape opposite to that of the horizontal deflection coil 12t-projection tube 1R.

In this way, by making the shape of the deflection coil asymmetrical, the magnetic field generated by K is made asymmetrical with respect to the tube axis, and a raster of a desired shape can be formed on the fluorescent surface of the projection tube with a simple configuration. In this case, the asymmetric magnetic field due to the shape of the conductor P group of the horizontal deflection coil and the shape of the fringe section combine to cause a horizontal trapezoidal distortion in the raster, and the asymmetric magnetic field due to the shape of the side conductor of the horizontal deflection coil causes the raster to be distorted. In the above embodiment, each coil of the single direct deflection coil has the same number of turns,
Although the case where the shape is asymmetrical to the t'1taI plane has been described, it is clear that the same effect can be obtained by changing the number of windings to make the shape symmetrical or asymmetrical to the shape tlii plane.

As explained above, according to the present invention, horizontal.

By forming the vertical deflection coil asymmetrically, a horizontal and deflection magnetic field sound asymmetrical with respect to the tube axis is generated, and a raster with the desired distortion t is generated.The operation is stable without increasing the distortion t, and the operation is stable. It is possible to sufficiently eliminate horizontal trapezoidal distortion and changes in horizontal linearity of the above projection 1, and to provide a projection tube deflection yoke with excellent functions at a low cost while eliminating the drawbacks of the conventional technology.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing a projection television apparatus, Fig. 2 is an explanatory drawing showing the projection twister of each projection tube on the screen, and Fig. 3 is an explanatory diagram showing the projection twister of each projection tube on the screen. An explanatory diagram showing an example of a raster, FIG. 4 is a configuration diagram showing an example of a configuration for completely correcting the distortion of the image on the projection screen of FIG. The sixth factor is a front view showing an example of the vertical deflection coil, Figure 7 is an explanatory diagram showing the action of the vertical deflection coil in Figure 6, and Figure 8 is a projection due to the action. 9 is a front view showing another embodiment of the vertical deflection coil of the deflection yoke shown in FIG. 5; FIG. 10 is an explanatory view showing the action of the vertical deflection coil shown in FIG. 9; FIG. 11 is an explanatory diagram showing the projection tube's rask due to its effect, FIG. 12 is an explanatory diagram showing the composite raster of the rasters shown in FIGS. 8 and 11, and FIG. FIG. 14 is a front view showing an example of the horizontal deflection coil, FIG. 13 is an explanatory diagram showing the action of the horizontal deflection coil, and FIG. 0 12...Horizontal deflection coil, 12a-1-12a
-z. 12b-1, 12b-I... Side conductor of horizontal deflection coil, 13... Vertical deflection coil,
13a, 13b...1 conductor group of direct deflection coil, 15t-15z...-fringe portion of deflection coil, 19, 19'...opposite surface 0 years IFi'I 72bu Go b 4th mouth (a) 78 Maro lb '210 Figure 79 Figure 711

Claims (1)

[Scope of Claims] (1) A pair of coils wound in a hollow shape used in a projection television device that projects images from a direction oblique to the vertical center line of a projection screen. In the deflection yoke of a projection tube, the deflection yoke of a projection tube is provided with means for making the magnetic field distribution by the deflection coil asymmetrical with respect to the tube axis of the projection tube, and the raster on the projection tube is distorted. A deflection yoke of a projection tube characterized in that it is configured to cancel the Lascou distortion on the projection screen. A deflection yoke of a projection tube characterized in that the deflection yokes are different from each other. (3) Claim 1: tfc is #! A deflection yoke of a projection tube characterized in that the deflection yoke of a projection tube is constructed of two intersecting planes including: - Deflection eye of projection tube characterized by (5) 41 Claim iL In paragraph 1, the means is characterized in that the coil pair is symmetrical with respect to a plane facing the coils, and A deflection yoke for a projection tube, characterized in that the deflection yoke is asymmetrical with respect to a plane that is perpendicular to the surface facing the coil and that includes the tube axis.