JP2005159805A - Projection color display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce horizontal trapezoidal distortion of R and B screens with no increase in the amount of power consumption of a projection color display. <P>SOLUTION: There are provided a screen (5) and red, green, and blue cathode ray tubes (1R, 1G, and 1B) which are attached with deflection yokes (3R, 3G, and 3B) comprising a pair of vertical deflection coils (6-9) for projecting the images of red, green, and blue. In projection configuration, the cathode ray tubes (1R, 1G, and 1B) are arranged in parallel in the order of red, blue, and green, and the images are synthesized on the screen (5). In the cathode ray tubes (1R, and 1B) for red and blue, the numbers of turns are different among the pair of vertical deflection coils (6-9). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projection color display.

The projection type color display includes a projection cathode ray tube with a deflection yoke mounted on the neck portion, which projects each color image of red (R), green (G), and blue (B), and the R, G, B images thereof. Are combined with an optical lens while being magnified and projected onto a screen.
As a conventional example of this projection type color display, there is one described in Patent Document 1.

In this conventional projection type color display, a deflection yoke with a convergence yoke for correcting image distortion is mounted on the neck portion of each color projection tube, and the deflection sensitivity of the convergence yoke mounted on the R projection tube and the B projection tube is improved. The deflection sensitivity of the convergence yoke mounted on the G projection tube is improved.
Japanese Patent Application Laid-Open No. 7-232145

In general, the cathode ray tubes 1R, 1G, and 1B of the projection type color display are arranged in the order of R, G, and B, and the R and B cathode ray tubes 1R and 1B on both ends are set at a predetermined angle θ with respect to the screen 5. Is fixed to a display casing (not shown) (see FIG. 5).
In FIG. 5, a deflection yoke 30 and a convergence yoke 40 are mounted on the neck portions of the cathode ray tubes 1R, 1G, and 1B, and an image is enlarged by the magnifying lens 2 and projected onto the screen 5. Therefore, as shown in FIGS. 6A, 6B, and 6C, the projection distortion of the R and B images is larger than that of the image of the G cathode ray tube. That is, the R image exhibits a horizontal trapezoidal distortion that opens right and the B image exhibits a left opening. FIG. 6 is a view when the screen 5 is viewed from the opposite side of the cathode ray tube.

The projection type color display described in Patent Document 1 is intended to correct this horizontal trapezoidal distortion by making a difference in the deflection sensitivity of the convergence yoke.
However, there is a problem that the cost is increased due to the increase in the size of the core and the number of parts increases.

On the other hand, a method of correcting this by increasing the current flowing through the convergence yoke 4 is also known.
However, in this case, the power consumption increases, and a correction circuit (not shown) for driving the heat generation generates a larger amount of heat, and the components for heat dissipation are increased in size.
In particular, in recent years when power saving is required, this power consumption must be reduced as much as possible, which is a big problem.

  Therefore, an object of the present invention is to provide a projection color display that reduces horizontal trapezoidal distortion of R and B screens without increasing power consumption.

In order to solve the above problems, the present invention has the following configuration as means.
That is, the invention according to claim 1 is equipped with a screen (5) and a deflection yoke (3R, 3G, 3B) having a pair of vertical deflection coils (6-9), and displays each image of red, green and blue. The cathode ray tubes (1R, 1G, 1B) for red, green, and blue that project respectively, and the cathode ray tubes (1R, 1G, 1B) are arranged in parallel in the order of red, blue, and green. A projection color display configured to project the images on the screen (5) so as to be combined on the screen (5),
A projection-type color display (50), wherein the red and blue cathode-ray tubes (1R, 1B) have different numbers of turns in the pair of vertical deflection coils (6-9). .

  According to the present invention, there is an effect that horizontal trapezoidal distortion can be reduced without increasing power consumption.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram showing an embodiment of a projection type color display of the present invention.
FIG. 2 is a diagram for explaining the first main part and its operation in the embodiment of the projection color display of the present invention,
FIG. 3 is a diagram for explaining a second main part and its operation in the embodiment of the projection color display of the present invention,
FIG. 4 is a diagram for explaining an image projected in the embodiment of the projection type color display of the present invention.

FIG. 1 is a schematic plan view for explaining an embodiment of a projection color display of the present invention.
The projection color display 50 projects images of the screen 5 and three colors of red (R), green (G), and blue (B) (hereinafter referred to as R, G, and B) onto the screen 5. Cathode ray tubes 1R, 1G, and 1B, and a magnifying lens 2 for enlarging the display images of the cathode ray tubes 1R, 1G, and 1B are provided.

Deflection yokes 3R, 3G, 3B and convergence yokes 4, 4, 4 are mounted on the respective cathode ray tubes 1R, 1G, 1B.
Further, B, G, and R cathode-ray tubes 1B, 1G, and 1R are arranged in the horizontal direction in order from the left side in FIG. 1, and a projected image of G is projected perpendicularly to the screen 5, and R and B Is projected at a predetermined angle θ with respect to the screen 5.

FIG. 2A is a schematic diagram of the deflection yoke 3R mounted on the R cathode-ray tube 1R in the projection color display embodiment of the present invention, taken along the line YY in FIG. The vertical deflection coils 9 and 8 are shown.
In this deflection yoke 3R, the number of turns of the right vertical deflection coil 8 (shaded portion) is larger than the number of turns of the left vertical deflection coil 9.
Therefore, the magnetic field generated by the right vertical deflection coil 8 is stronger than the magnetic field generated by the left vertical deflection coil 9, and the vertical amplitude when the electron beam on the right side of the screen is vertically deflected is higher than that on the left side. growing. The length of the arrow in FIG. 2 (a) indicates the magnitude of the vertical amplitude at this time.
As a result, as shown in FIG. 2B, the displayed image is subjected to right-opening correction as viewed from the cathode line side, which cancels out the left-open image distortion before correction.
Therefore, an R image without distortion can be obtained as shown in FIG.

On the other hand, in the deflection yoke 3B, the number of wire turns of the left vertical deflection coil 7 (shaded portion) is larger than the number of wire turns of the right vertical deflection coil 6.
For this reason, the magnetic field generated by the left vertical deflection coil 7 is stronger than the magnetic field generated by the right vertical deflection coil 6, and the vertical amplitude when the electron beam on the left side of the screen is vertically deflected is higher than that on the right side. growing. The length of the arrow in FIG. 3A indicates the magnitude of the vertical amplitude at this time.
As a result, as shown in FIG. 3B, the displayed image is subjected to left-open correction as viewed from the cathode ray tube side, which cancels out the right-open image distortion before correction.
Therefore, a B image without distortion can be obtained as shown in FIG.
On the other hand, since the G image is an image having no horizontal trapezoidal distortion (see FIG. 4B), the projected image obtained by combining the R, G, and B images also has a high quality without horizontal trapezoidal distortion.
The projected image also has vertical and horizontal pincushion distortion, which can be corrected by applying an appropriate correction current to the convergence yoke. FIG. 4 shows a case where this pincushion distortion is appropriately corrected.

  In the embodiment described above, the pair of left and right vertical deflection coils 9, 8, 7, 6 in the R and B image deflection yokes 3 </ b> R and 3 </ b> B are not increased without increasing the current flowing through the vertical deflection coils 6 to 9. Horizontal trapezoidal distortion can be corrected by making the number of turns unbalanced. Therefore, this correction does not increase the power consumption of the projection type color display.

An example of horizontal trapezoidal distortion correction in the above embodiment will be described next.
In a projection type color display in which the horizontal trapezoidal distortion ratio on the screen on the projection screen before correction is about 8 to 9% with respect to the normal screen, the right and left turn ratio of the vertical deflection coils 7 and 6 of the R deflection yoke 3R. Was set to 1: 2, and the left / right turn ratio of the vertical deflection coils 9 and 8 of the B deflection yoke 3B was set to 2: 1.
At this time, the horizontal trapezoidal distortion ratio on the display screen of the R and B cathode-ray tubes 1R and 1B is about 8% with respect to the regular screen, which is offset by the horizontal trapezoidal distortion ratio on the projection screen. Was almost corrected.

  In this case, the wire cross-sectional area of the coil with a turns ratio of 1 is set to be twice that of the coil with a turns ratio of 2, and the space factor in the cavity in the coil winding mold is made equal. The method includes doubling the wire diameter of a coil having a turns ratio of 1, or using bifilar winding.

  By the way, it is possible to change the horizontal trapezoidal distortion correction amount by changing the left and right turn ratio of the vertical deflection coil, and increasing this turn ratio increases the correction amount. This relationship is shown in Table 1.

投写スクリーン面上の水平台形歪み量は、Ｂ，Ｒの画像がスクリーン５に投写する所定の角度θによって決まるので、この角度θに応じて垂直偏向コイル６〜９の左右の巻数比を、その巻数比で得られる表１に示すような補正量とスクリーン５面上画面の水平台形歪み量とが相殺するように設定すればよい。

Since the amount of horizontal trapezoidal distortion on the projection screen surface is determined by a predetermined angle θ at which the B and R images are projected onto the screen 5, the right and left turn ratios of the vertical deflection coils 6 to 9 are determined according to the angle θ. What is necessary is just to set so that the amount of correction shown in Table 1 obtained by the winding ratio and the amount of horizontal trapezoidal distortion of the screen on the screen 5 may cancel each other.

The embodiment of the present invention is not limited to the configuration and procedure described above, and it goes without saying that modifications may be made without departing from the scope of the present invention.
In the above-described embodiment, a general example in which three cathode ray tubes are arranged in the order of B, G, and R from the left has been described. However, the present invention is not limited to this, and this color arrangement may be freely set. . In that case, the above-described configuration in which the turn ratio is changed may be applied to the vertical deflection coils of the deflection yokes of the two outer cathode ray tubes among the three cathode ray tubes arranged in a row.

It is a figure which shows the Example of the projection type color display of this invention. It is a figure explaining the 1st principal part in the Example of the projection type color display of this invention, and its effect | action. It is a figure explaining the 2nd principal part in the Example of the projection type color display of this invention, and its effect | action. It is a figure explaining the image projected in the Example of the projection type color display of this invention. It is a figure explaining the conventional projection type color display. It is a figure explaining horizontal trapezoid distortion.

Explanation of symbols

1R, 1G, 1B Cathode ray tube 2 Magnifying lens 3R, 3G, 3B Deflection yoke 4 Convergence yoke 5 Screen 6-9 Vertical deflection coil 10 Case 50 Projection type color display θ (projection) angle

Claims (1)

Screen,
A deflection yoke having a pair of vertical deflection coils is mounted, and comprises red, green and blue cathode ray tubes for projecting red, green and blue images, respectively.
A projection color display in which the cathode ray tubes are arranged in parallel in the order of red, blue, and green, and the respective images are projected onto the screen so as to be combined on the screen,
A projection-type color display, wherein the red and blue cathode-ray tubes have different numbers of turns in the pair of vertical deflection coils.

Images