JPS58100344A - Cathode-ray tube for projection - Google Patents

Abstract

PURPOSE:To offset the generating change of horizontal linearity and fully correct or reduce the misoconvergence caused by the change of horizontal linearity by slanting a projecting optical axis in relation to a screen on a projection screen face. CONSTITUTION:In a CRT1R for projection, the right and left lengths between the central axis 10 of the CRT for projection and the wall surface is assymetrical in the cross section vertical to the central axis 10 of the CRT1R for projection in a funnel and a neck, that is, the left length is shorter than the right length. Therefore, when a deflection yoke is mounted, both the central axis 10 of the CRT for projection and the central axis 14 of the deflection yoke can be made eccentric, and the central axis 10 of the CRT for projection can be set to the left of the central axis 14 of the deflection yoke. On the other hand, a horizontally deflected magnetic field is made more infeuse in its periphery in relation to the central axis 14 of the deflection yoke. As a result, the force 15a of the horizontal deflection of an electron beam, when the beam is deflected left is larger than 15b when it is deflected right.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a projection cathode ray tube (hereinafter referred to as a projection t' RT) used in a projection television apparatus.

Generally, a projection type television apparatus using a projection CRT is composed of a projection CRT 1, a lens 2, a screen 4, etc., as shown in FIG. In such a projection unit television set l11m, as shown in FIG.
' If the projection optical axis 3 formed by RT 1 and lens 2 is IlK with respect to the screen 4, the image of the projection C"RTl will appear on the screen 4 as it is linearly enlarged.

If the image on the projection CRT i is rectangular, it is screen 4.
The image reproduced above also becomes a precise rectangle as shown by the 51st real @S. However, as shown in the second prisoner, the projection optical axis 3 consisting of the projection C'RT1 and the lens 2
is tilted in the horizontal direction by a certain angle with respect to the screen 4, even if the image reproduced on the projection t'RT1 is an exact rectangle, the image reproduced on the screen 4 will be as shown in Figure 5. As shown in , the horizontal linearity changes and the image has horizontal trapezoidal distortion.

In order to correct changes in horizontal linearity and horizontal keystone distortion of the image reproduced on the screen 4, conventionally the projection t'R
The oiu*Y that occurs on T is corrected by electrically distorting it using a distortion correction oil path in advance, and canceling out that electrical distortion with the above-mentioned change in horizontal linearity and horizontal trapezoidal distortion. be.

However, the electric oil path for correcting this distortion is not only complicated, but also has the drawback of being unstable against electrical changes. In particular, as shown in Figure 4, the three primary color lights of red (R), edge (G), and blue (B) are projected from separate positions and mixed on the screen 4 to create a color image. If you are trying to obtain it, what are the changes in the horizontal linearity and horizontal trapezoidal distortion of the red image on the surface of the screen 4 and the changes in the horizontal am characteristic of the blue IIIDI and the horizontal trapezoidal distortion, as shown in No. 5-. There is a misconvergence (color shift) between the green image that is played in the opposite direction and the rectangle shown by the dashed line.
' to occur. In this case, the electrical correction Ig1wI becomes more complicated, and as shown in the fs6 diagram, the electrical correction (, 'R
It is necessary to provide a sub-deflection yoke 8 in 7'1R11B and 1G, and this sub-deflection yoke 8 is supplied with a separate current for all corrections. !
-It has to flow. In this way, it is extremely difficult to adjust conventional projection television equipment! Become something.

In this case, electrical fluctuations worsen misconvergence and degrade image quality, so a high degree of stability is required for the first correction path.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to improve the ability to reproduce water on the screen by changing the horizontal linearity of the raster and by horizontal trapezoidal distortion! Of the misconvergence that occurs in the II image, the misconvergence that occurs due to changes in raster characteristics is sufficiently corrected or reduced,
The object of the present invention is to provide a projection t' RT which makes it possible to eliminate or simplify the electrical correction bwr.

In the present invention, the length from the central axis of the projection t' RT to the wall surface is asymmetrical in the cross section in the direction perpendicular to the central axis of the projection CRT in the funnel and neck of the projection t' RT. This dosing CRT is equipped with a deflection yoke, which is a horizontal deflection coil of #X, in which the strength of the horizontal deflection magnetic field is different between the center axis and the periphery of the deflection yoke in a cross section perpendicular to the center axis of the deflection yoke. It is more biased than the mounting method K.

The present invention will be described below with reference to an actual example of an electrode tube for projection shown in the drawings. As mentioned above, the horizontal [4i] changes that occur in the image reproduced on the screen are corrected.In the present invention, the fluorescence of the projection t' RT is When viewing an image on a surface from the electron gun side, a change in horizontal linearity is created in advance on the fluorescent surface of the projection CRT in the same direction as the change in horizontal linearity that occurs in the image reproduced on the screen. It is necessary to compensate for the change in horizontal linearity that occurs when the image is reproduced on the screen. Therefore, a red projection CRT IR' as shown in FIG.
from the right side.

Blue CRT 1BY: Projection TV installation when projecting from the left side [Red projection t'RT in K
IH will be explained.

In the following description, the image on the phosphor surface of the projection t' Rr, t' RT , and the cutoff of the deflection magnetic field [o@] will be explained as being viewed from the electron gun side. In order to obtain a raster image with no change in horizontal IL linearity on the projection screen surface, the change in horizontal linearity that needs to be formed on the fluorescent surface of the red projection t' RT I H is as shown in Figure 7. Demeri,
The left horizontal line 9α is longer than the right horizontal line @9b.

FIG. 8 shows a plan view of the projection CRT1H according to the present invention, and FIG. 9 shows a plan view of the projection CRT1H according to the present invention.
A sectional view in a direction perpendicular to the central axis 10 of the projection CRT 1R at the annular or neck portion is shown. In the projection t' RT1H according to the present invention shown in FIGS. 8 and 9, the projection t' RT I H in the funnel and neck is
In the cross section perpendicular to the central axis 10 of the projection t
' The length from the central axis 10 of RTlR to the wall [ii] is asymmetrical, with the length on the left side being shorter than the length on the right side. Figure 10 shows the state of the horizontal deflection magnetic field 12 of the horizontal deflection coil 11 that constitutes the deflection yoke attached to the projection CRTK according to the present invention shown in Figures 8 and 9. This is a cross section taken in a direction perpendicular to the central axis 14 of.

The horizontal deflection magnetic field 12 shown in FIG. 10 is stronger at the periphery of the center axis 14 of the deflection yoke.

The shape of the raster reproduced on the projection t' RT fluorescent surface when a deflection yoke is attached to the projection/re-projection CRT 1R according to the present invention will be described. The eleventh diagram is a diagram illustrating the deflection force exerted on the electron beam K in the seven channels or necks of the projection t'RT1R according to the present invention in the horizontal deflection magnetic field 12 of the horizontal deflection coil 11. For projection related to the present invention (,' RT 1H
CRT for projection in funnel and neck trap
Projection t in a cross section perpendicular to the central axis 10 of 1H
' The length from the central axis 10 of the RT to the wall surface is asymmetrical, and the length on the left side is shorter than the length on the right side, so when a deflection yoke is installed, the work shown in l@1t@ The central axis 10 of the projection CRT and the central axis 14 of the deflection yoke can be made eccentric, and the central axis 10 of the projection CRT can be placed to the left of the central axis 14 of the deflection yoke. On the other hand, the horizontal deflection magnetic field is located at the center of the deflection yoke.
In contrast, the surrounding ten thousand people are becoming stronger. Therefore, the horizontal deflection force 15 of the electron beam is larger when the electron beam is deflected to the left (15G) than when it is deflected to the right (154). Therefore, the raster on the fluorescent surface of the projection C''R11H can form a desired change in horizontal linearity that is longer than the horizontal line 9α on the left side or the horizontal line 9b on the right side, as shown in FIG. .

As a result, on the projection screen surface of a projection television set, the horizontal change caused by the projection optical axis being tilted with respect to the screen is offset.
Misconvergence caused by changes in horizontal illumination can be sufficiently compensated for or even reduced.

In the above explanation, the horizontal deflection magnetic field is stronger on the side with respect to the center axis 14 of the deflection yoke, but the horizontal deflection magnetic field 12 is stronger on the side with respect to the center axis 14 of the deflection yoke. If it is weak, use C for projection.

R71R is the left and right reversed haze of the above-mentioned projection t'RT1B, that is, the length from the central axis 10 of the projection CRT to the wall surface in a cross section perpendicular to the central axis 10 of the projection t'RT in the funnel and neck. about,
The length on the left side should be longer than the length on the right side.

Although the above explanation has been made regarding the red projection t'RTIH, it is clear that the blue projection C'R11B can be easily reversed to the left and right of the red C' RT 1R.

As described above, in the funnel and neck of the projection t' RT, in the cross section perpendicular to the central axis of the projection CRT, the length t of the wall surface from the central axis of the dosing t' RT is asymmetrical, so that the deflection yoke is The method of making the center axis of the projection CRT and the center axis of the deflection yoke eccentric when a projection CRT is installed is to make the inner diameter of the deflection yoke larger than the funnel and neck diameter of the projection t'Rr to provide a margin. Compared to a method in which the central axis of the projection C'λT and the central axis of the deflection yoke are made eccentric, this method has the advantage of better deflection sensitivity.

Furthermore, the deflection yaw is small and compact, and the cost of the deflection yoke is reduced.

The present invention is constructed as described above.

Eliminate or simplify the electrical correction circuit that compensates for misconvergence due to changes in horizontal linearity by sufficiently compensating for or reducing changes in horizontal linearity that cause misconvergence on the screen. T
It is possible to obtain economical and stable images.

[Brief explanation of the drawing]

Box 1 and Figure 2 are schematic diagrams showing the relationship between the screen and the projection device in a projection television equipment, tl, 5
@ is a pattern diagram showing changes in the horizontal linearity of the projected image reproduced on the screen surface and horizontal plate engraving, Figure 4 is a schematic diagram showing the color projection device, and Figure 5 is the color projection device shown in Figure 4. Pattern diagram showing the misconvergence pattern that occurs in the y:th image reproduced on the screen surface of
The figure is a plan view showing the structure of the projection t' RT, the false yoke, and the opposite yoke. Figure 7 shows the red projection t'
Horizontal patterns required to be formed on the fluorescent surface of T1H [L4I characteristics change-1] Figure 8 shows the flat pattern of the projection CRT according to the present invention, and Figure 9 shows the flat pattern of the projection CRT according to the present invention. Projection t' in the anneal or neck
10 is a cross-sectional view in a direction perpendicular to the RT central axis; FIG. 10 is a pattern diagram showing the shape of magnetic lines of force on the Ir plane in the direction of the deflection yoke central axis and the angle of the crest of the horizontal deflection coil that constitutes the deflection yoke;
FIG. 11 is a diagram showing the strength of the horizontal deflection applied to the electron beam in the funnel or neck of the projection C''R-T according to the present invention in a horizontal deflection magnetic field. 10...For projection Central axis 11 of L°Rr...Horizontal deflection coil 12...Horizontal deflection magnetic field 1'5...Core 14...One central axis of cylinder yoke 15...Horizontal deflection force 1wJ 2z 3ffi ′″lt′411EI SaiS Figure O6? 7 ferrite ′; F8 drawing size 9 drawing Olθ

Claims (1)

[Claims] t The length from the central axis of the projection cathode ray tube to the wall case in the funnel and neck of the projection cathode ray tube used for projection television installation in a cross section perpendicular to the central axis of the projection cathode ray tube. A cathode ray tube for projection is characterized by asymmetrical projection.