JPH04233879A - Projection television - Google Patents

Abstract

PURPOSE:To eliminate the uneven luminance caused by seizure of a fluorescent screen of a projection tube, to reduce the power consumption per unit of the fluorescent screen, and to reduce the aberration of a projection lens at the time of converting a luminous flux. CONSTITUTION:By using a projection tube 31 having an aspect ratio of a standard television system or between the standard television system and other television system than the standard television system, images of the standard television system and other television system than the standard television system are projected selectively onto its fluorescent screen in a state that raster dimensions are held constant, and also, in accordance with a signal of the inputted television system, a conforming projection lens 32 is selected, by which the image having an aspect ratio confirming the television system concerned is projected onto a screen 33.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention selectively projects signal images of different aspect ratios (vertical and horizontal ratios) on the fluorescent screen of a projection cathode ray tube (projection tube) in the same raster size. The present invention relates to an improvement in a projection television in which a signal image of the original aspect ratio is projected onto a screen through a projection lens.

0002

2. Description of the Related Art Conventionally, an image of a high-definition television (HDTV) (hereinafter referred to as television) signal having an aspect ratio of 16:9 and an image of a standard television signal having an aspect ratio of 4:3 have conventionally been used. A projection television that projects images in the same raster size onto the same projection tube and selectively projects the projected images onto the screen using the same optical device is disclosed in Japanese Patent Application Laid-Open No. 2-194783. something is known.

The invention described in the above-mentioned publication has a configuration as shown in FIG. When projecting an image of a high quality television signal, the image is projected onto a screen 44 through a normal projection lens 42.
Furthermore, when projecting an image of a standard television signal onto the projection tube 41, the standard television signal input to the projection tube 41 is converted in advance so that it has an aspect ratio equal to that of a high-definition television signal. However, to project the image onto the screen 44, the normal projection lens 42 and the luminous flux conversion lens 43 are used together as a projection lens to convert the luminous flux, and the aspect ratio of the standard television signal is projected onto the screen 44. The image is projected as an image equal to the ratio.

With this configuration, it is possible to eliminate uneven brightness caused by burn-in on the fluorescent screen of the projection tube 41, which tends to occur in this type of projection television.

[0005]

[Problems to be Solved by the Invention] Although it is possible to eliminate uneven brightness due to burn-in of the phosphor screen of the projection tube in the conventional projection television, it is difficult to solve the problem of the shape of the phosphor screen of the projection tube and the power consumption of the projection tube. , no consideration is given to lens aberrations of the projection lens, etc.

[0006] To further discuss this point, because the conventional projection television uses a projection tube for high-definition television signals, the phosphor screen is considerably longer in width than in height, and red, blue, green, and red. When arranging the tubes in parallel, there is a limit to their width. Furthermore, in the projection tube for high-quality television signals, the horizontally elongated shape of the phosphor screen increases power consumption per unit area of the phosphor screen. Furthermore, when the standard television signal image projected on the high-definition television signal projection tube is converted into a luminous flux by the projection lens, the aspect ratio conversion rate is relatively large, so lens aberrations during the conversion are reduced. It becomes impossible to ignore.

The present invention has been devised to eliminate such problems, and can eliminate uneven brightness caused by burn-in on the projection screen, and also has a To provide a projection television that does not require much consideration to the width of the phosphor screen of a projection tube, consumes less power per unit area of the phosphor screen, and can significantly reduce lens aberrations during luminous flux conversion by the projection lens. It is intended to.

[0008]

Means for Solving the Problems In order to achieve the above object, the first aspect of the present invention is to provide a projection tube with a constant raster dimension on a phosphor screen of a projection tube having an aspect ratio of a standard television signal. Selectively projects images of standard television format signals and television format signals other than the standard television format, such as high-definition television format signals, depending on which of the aforementioned formats the input signal is. By converting the lens, an image having an aspect ratio corresponding to both of the above-mentioned systems is projected onto the screen.

[0009] The second aspect of the present invention is that a signal of a standard television system and a signal of a television system other than the standard television system,
For example, an image of a standard television system signal and a high definition television system signal can be selectively displayed on a fluorescent screen of a projection tube that has an aspect ratio intermediate to that of a high definition television system signal, while keeping the raster dimension constant. By converting the projection lens depending on which of the above methods the input signal is, an image having an aspect ratio compatible with both of the above methods is projected onto the screen. It is.

0010

[Operation] The aspect ratio (4:3) obtained by converting the signal of a television system other than the standard television system, such as a high-definition television system, is displayed on the fluorescent screen of the projection tube which has the aspect ratio of the standard television system (4:3). 3) Projects a high-definition television system signal image, converts the light flux of the image using a projection lens such as an anamorphic lens used in cinemascope projection, and displays it on a screen. When projected, a high-quality television signal image with an aspect ratio of 16:9 can be obtained on the screen.

[0011] Furthermore, the signal of the high-definition television system is displayed on the phosphor screen of the projection tube, which has an aspect ratio between the signal images of the standard television system and the television system other than the standard television system, for example, the high-definition television system. selectively displaying a high-definition television system signal image with an intermediate aspect ratio obtained by conversion, or a standard television system signal image with an intermediate aspect ratio obtained by converting a standard television system signal; If this image is converted into luminous flux using each projection lens such as an anamorphic lens and projected onto a screen, a high-definition television with an aspect ratio of 16:9 will be displayed on the screen. method signal image,
Alternatively, a standard television format signal image with an aspect ratio of 4:3 can be selectively obtained.

0012

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

FIG. 1 shows a first embodiment of the present invention, in which numeral 11 is a projection tube whose phosphor screen has an aspect ratio of 4:3 for a standard television system signal image; A normal projection lens 13 is used when the image of the projection tube 11 is a signal of a television system other than the standard television system, in this example, a high-definition television system. 14 is a projection screen.

Normally, when the projection lens 12 is inserted into the projection optical path, the anamorphic projection lens 13 is removed from the optical path, and as shown in the figure, the anamorphic projection lens 13 is inserted into the projection optical path. When the projection lens 12 is inserted into the optical path, the projection lens 12 is normally removed from the optical path. Further, the anamorphic projection lens 13 used in this embodiment is 4/3
It has a conversion ratio of , and is composed of a combination of multiple anamorphic lenses.

Now, when a converted high-definition television system signal image is being projected on the fluorescent screen of the projection tube 11,
As shown, anamorphic projection lens 1
3 is selectively inserted into the projection optical path, and the image with an aspect ratio of 4:3 projected on the fluorescent screen is projected onto the screen 14 as an image with an aspect ratio of 16:9. On the other hand, when a standard television system signal image is projected on the fluorescent screen of the projection tube 11, the projection lens 12 is normally switched and inserted into the optical path, and the aspect ratio of the image projected on the fluorescent screen is 4:
3 is displayed on the screen 14 with an aspect ratio of 4.
: Projected as an image of 3.

In this case, the conversion between the normal projection lens 12 and the anamorphic projection lens 13 is performed by converting the lens 12,
Although this is done by replacing the entire lens 13, instead of such replacement, the anamorphic ratio may be changed by replacing or moving a part of the lenses 12, 13.

Furthermore, if zooming is performed using a combination of the anamorphic projection lens 13 and a zoom lens, projection is less affected by lens aberrations than when the anamorphic projection lens 13 is used alone. You can get the image.

FIG. 2 shows a block diagram of a signal conversion circuit used in the present invention, and 21 is a signal input terminal for a television system other than the standard television system, for example, a high-definition television system;
22 is a standard television system signal input terminal, 23 is a sync separation circuit, 24 is a video signal processing circuit, 25 is a vertical deflection circuit, 26 is a horizontal deflection circuit, and 27 is an adjustment circuit.

In the figure, a high-definition television system signal input to an input terminal 21 has a synchronization signal separated in a synchronization separation circuit 23, and a video signal obtained at the output of the synchronization separation circuit 23 is processed in a signal processing circuit 24. and is supplied to the projection tube 11. Further, the amplitude of the separated synchronization signal is adjusted in the adjustment circuit 27, and then the projection tube 11
supplied to As a result, the fluorescent screen of the projection tube 11 has 4
A high-definition television signal image adjusted to have an aspect ratio of :3 is displayed on the entire phosphor screen in a slightly elongated format.

On the other hand, the synchronization signal of the standard television system signal inputted to the input terminal 22 is separated in the synchronization separation circuit 23, and the video signal obtained as the output thereof is processed in the signal processing circuit 24, as described above. As in the case, the separated synchronization signal is supplied to the projection tube 11 without any adjustment, and a standard television signal image is displayed on the entire phosphor screen of the projection tube 11.

According to this embodiment, since the projection tube 11 has a phosphor screen with an aspect ratio of 4:3 for a standard television signal image, the phosphor screen has an aspect ratio of 16:9. Compared to conventional projection TVs, when the width of the projection tube is held constant, the vertical width can be expanded, so the area of the phosphor screen can be expanded by that amount, which reduces the amount of power consumed per unit area of the phosphor screen. can be reduced. Therefore, the temperature rise of the projection tube is suppressed, and the reliability of the projection tube can be improved, and the saturation of the phosphor can also be improved. Furthermore, since the spacing between raster scanning lines is widened, vertical resolution is improved when the spot diameter of the electron beam is kept constant.

FIG. 3 shows a second embodiment of the present invention, in which a phosphor screen 31 has a television system other than the standard television system, for example, the aspect ratio of each signal image of the high-definition television system and the standard television system. A projection tube having an intermediate aspect ratio of 8:3√3, 32 an anamorphic projection lens used for light flux conversion, and 33 a projection screen.

[0023] Then, the anamorphic projection lens 32
is the first position as shown and then 90
It is configured such that it can be selectively set to a second position rotated by a degree. In this case, the anamorphic projection lens 32 has a conversion ratio of 2/√3 when in the first position, and has a conversion ratio of √3/2 when in the second position. As in the above-described embodiment, it is constructed by a combination of a plurality of anamorphic lenses.

In this embodiment, when a converted high-definition television signal image is projected on the fluorescent screen of the projection tube 31, the projection anamorphic lens 32 is moved to the first position as shown in the figure. and projected on the fluorescent screen with an aspect ratio of 8:3√
The image No. 3 is subjected to luminous flux conversion by the anamorphic projection lens 32 with a conversion ratio of 2/√3 located at the first position, and is projected onto the screen 33 as an image with an aspect ratio of 16:9.

On the other hand, when a standard television system signal image is projected on the fluorescent screen of the projection tube 1, the anamorphic projection lens 32 is selectively arranged at the second position, and the fluorescent screen Aspect ratio 8:3√3 projected on the screen
The image is subjected to luminous flux conversion by an anamorphic projection lens 32 with a conversion ratio of √3/2 located at a second position, and is projected onto a screen 33 as an image with an aspect ratio of 4:3.

In this embodiment as well, a signal conversion circuit as shown in FIG. 2 is used to convert the high-definition television system signal and the standard television system signal. Deflection circuit 15 and/or horizontal deflection circuit 16
At , the conversion is performed by adjusting the deflection voltage amplitude.

According to this embodiment, in addition to retaining the advantages of the previous embodiments, the anamorphic projection lens 32
Since the conversion ratio can be reduced to 1/2, the aberration of the anamorphic projection lens 32 can be drastically reduced compared to the above embodiment.

Also, in this embodiment, as in the previous embodiment, if zooming is performed by combining the anamorphic projection lens 32 and the zoom lens, it is possible to perform zooming by using the anamorphic projection lens 32 alone. It is possible to obtain a projected image that is more unaffected by lens aberrations than in the case of the present invention.

In this embodiment, the aspect ratio of the phosphor screen of the projection tube 31 is set to an aspect ratio between the aspect ratio of 16:9 for the signal image of the high-definition television system and the aspect ratio of 4:3 for the signal image of the standard television system. Although a ratio of 8:3√3 is selected, the aspect ratio of the phosphor screen of the projection tube 31 may not be in the middle of these, but may be selected to have an aspect ratio that is slightly biased towards one of them. can.

In this case, for the transformation of the projection lens,
Either two anamorphic projection lenses 32 are prepared and they are selectively replaced, or one anamorphic projection lens 32 is selectively rotated by 90 degrees and the other anamorphic lens is simultaneously rotated. Additional use is preferred.

For example, if the aspect ratio of the phosphor screen of the projection tube 31 is selected to be an intermediate point closer to the aspect ratio of 16:9 of the signal image of the high-definition television system,
The aberration of the signal image of the high-definition television system can be made smaller than the aberration of the signal image of the standard television system.

In the above embodiment, the aspect ratio of the signal image of the standard television system is 4:3, and the aspect ratio of the signal image of the high-definition television system is 16:9. It goes without saying that the present invention can be implemented in the same manner even if it has a different aspect ratio, as long as it targets each signal image of a television system other than the standard television system.

Furthermore, in the above embodiments, the projection lens needs to be replaced depending on the type of television signal input to the projection television, but the type of the signal is automatically detected and the The conversion is automatically performed by replacing or rotating the projection lens depending on the type. For example, each input terminal 21 in FIG.
, 22 and the synchronous separation circuit 23, and the projection lens may be replaced or rotated based on the detection output of the circuit. Of course, the projection lens may be replaced or rotated manually as necessary.

Note that the present invention can be applied to both front projection and rear projection.

[0035]

According to the present invention, it is possible to eliminate uneven brightness due to burn-in on the phosphor screen of the projection tube, and there are fewer restrictions on the width of the phosphor screen of the projection tube than in conventional projection televisions of this type. , the power consumption per unit area of the phosphor screen is relatively small. Further, lens aberration in the projection lens is considerably reduced during luminous flux conversion, resulting in the effect that vertical resolution can be improved.

[0036] Also, in connection with the relatively low power consumption, the temperature rise of the projection tube can be suppressed;
This also has the secondary effect of improving the reliability of the projection tube and improving phosphor saturation.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of the present invention.

FIG. 2 is a block diagram showing a signal conversion circuit.

FIG. 3 is a perspective view showing a second embodiment of the invention.

FIG. 4 is a perspective view showing a conventional example.

[Explanation of symbols]

11 a projection tube 12 with a phosphor screen aspect ratio of 4:3;
42 Normal projection lens 13 Anamorphic projection lens 14, 33, 44 Projection screen 21 High quality TV signal input terminal 22 Standard TV signal input terminal 23 Sync separation circuit 24 Signal processing circuit 25 Vertical deflection circuit 26 Horizontal deflection circuit 27 Adjustment circuit 31 Projection tube 3 with a phosphor screen aspect ratio of 8:3√3
2 Anamorphic projection lens 4 that can be rotated 90 degrees
1 Projection tube 43 with a phosphor screen aspect ratio of 16:9
Lens for light flux conversion.

Claims (6)

[Claims] Claim 1: In a projection television that selectively projects each projection image of a standard television system signal and a television system signal other than the standard television system on a screen, the aspect ratio of the standard television system is changed. By selectively projecting the images of both of the above methods on the fluorescent screen of the projection tube with the raster size held constant, and converting the projection lens according to the input signal method, each method can be projected. A projection television characterized by projecting an image having an aspect ratio corresponding to a screen onto a screen. 2. In a projection television that selectively projects each projection image of a standard television system signal and a signal of a television system other than the standard television system on a screen, an intermediate between the two television systems is provided. Selectively displaying images of both television systems on a fluorescent screen of a projection tube having an aspect ratio while keeping raster dimensions constant, and converting a projection lens according to the input signal system. A projection television characterized by projecting an image having an aspect ratio corresponding to each method onto a screen. 3. A projection television according to claim 1 or 2, wherein the television system other than the standard television system is a high-definition television system. 4. A projection television according to claim 1, wherein the projection lens is converted between a normal lens and an anamorphic lens. 5. The projection television according to claim 2, wherein the transformation of the projection lens is performed by rotating an anamorphic lens. 6. The projection television according to claim 1 or 2, in addition to converting the projection lens.
A projection television characterized in that a zooming function is added to the projection lens.