RU2236764C1 - Large television screen - Google Patents

Abstract

FIELD: electrical engineering; large television screens assembled of picture tubes.

SUBSTANCE: large television screen is assembled of picture tubes whose screens are disposed in same plane and light-guide plates covering screen surfaces; light-guide plates are installed over raster perimeter in each picture tube and are assembled of horizontal, vertical, and angle plates, plates of adjacent picture tubes being in contact; plate width is chosen to cover part of raster receiving pre-compressed image. Light-guide plates are made of light guides whose inlet ends disposed in picture-tube screen plane have sectional area smaller than that of outlet ends; light guides forming outer surface of plates have similar inlet and outlet ends, respectively. Light guides are bent and their length increases toward light-guide plate of adjacent picture tube.

EFFECT: simplified design due to reduced number of light guides and enhanced brightness of image due to unidirectional emission of light by all light guides.

3 cl, 14 dwg

Description

The invention relates to the field of television technology, based on the use of receiving cathode ray tubes, and can be used in show business for showing enlarged images of artists performing on stage, for showing films, as displays for representing graphic and digital information, as well as in household appliances - in televisions with oversized screens, widescreen type and the new standard with an increased number of lines.

In the currently widely used large screens made up of picture tubes, dark streaks appear between the picture tube screens in the image. They arise due to the fact that the size of the raster on the picture tube is smaller than the dimensions of the latter in the plane of the screen.

Dark stripes are eliminated by various means, for example, in the RF patent No. 2094954 "Device for forming an image on a large screen" (1997, IPC N 01 N 5/72) afocal raster systems are installed along the perimeter of the radiating surface.

In German patent No. 3424877, IPC H 04 N 5/72, 1984, selected as a prototype, a large television screen is proposed, consisting of picture tubes, in which dark stripes are eliminated. In this device, the entire surface of the screen is blocked by light guide plates. These plates are made of optical fibers. Their input ends are located in the plane of the tubes of the picture tubes and are connected, and the output ends are apart. As a result, the optical fibers transmit images to the plane of the large screen in which the output ends are located. The latter are added to the television frame.

The disadvantages of this device are: 1 A very large number of optical fibers installed on the entire surface (on the rasters) of the picture tubes 2. Uneven brightness of the image on the large screen arising from different angles of inclination of the optical fibers. Very high complexity of manufacturing the entire structure

The objective of the invention is to simplify the design by reducing the number of optical fibers while improving the transmission quality of the brightness of the generated image due to the fact that all the optical fibers emit light in one direction.

For this, a large television screen is proposed, consisting of picture tubes whose screens are in the same plane, light guide plates overlapping the screen surface, while light guide plates are installed along the perimeter of the raster of each picture tube and are formed of horizontal, vertical and angular plates, and the plates of adjacent picture tubes are in contact, and the width of the plates is chosen such that it overlaps the part of the raster onto which a pre-compressed image is supplied, the light guide plates are made of light guides with the cross section of the input ends located in the plane of the tubes of the picture tubes smaller than the cross section of the output ends forming the outer surface of the light guide plates, while the cross sections of the input and output ends are the same, the light guides are curved, and the length of the light guides increases in the direction of the light guide plate neighboring picture tube.

In addition, the light guide plates can be made of light guides and gradan.

Also, light guide plates made of glass fibers can be embedded in the screens of the picture tubes so that their outer surfaces are one plane with the plane of the screen.

This television screen uses narrow waveguide plates with a small number of waveguides. The total number of optical fibers is tens of times less than in the prototype. Narrow light guide plates are placed at the edges of the rasters in the area of the picture tube docking, where dark bands are “formed” in commonly used devices, the rest of the picture tube screens are open. The task of narrow light guide plates is to “stretch” the part of the image specially compressed by the sweeps at the edges of the raster, before meeting the image of the adjacent picture tube. The brightness of the image on the open part of the kinescope screen and on the output ends of the narrow light guide plates is the same. A system with narrow light guide plates is much more economical to manufacture than a system with light guide plates occupying the entire screen area of the picture tubes.

Figure 1 shows a fragment of a large television screen, consisting of four picture tubes.

Figure 2 shows a cross section along AB in figure 1.

Figure 3 shows a cross section along the DS in figure 1.

Figure 4 shows a sectional view of vertical and horizontal light guide plates.

Figure 5 shows the characteristics of the deflecting currents in lines Y _c = f (t) and in frames Y _to f (t), as well as time intervals in lines t _c and in frames t _k during which the television signal illuminates the compressed image.

Figure 6 shows schematically the position of the lower and upper ends of the corner light guide plate (letter designations correspond to figure 5).

7 shows a section of an angled light guide plate.

On Fig shows a light guide plate made of plastic.

Fig. 9 shows a light guide plate with a lens array.

Figure 10 shows a light guide plate of gradanov.

Figure 11 shows the screen of the kinescope with light guide plates embedded in the frontal plane of the kinescope.

On Fig shows a section along the AV of Fig.11 and the connection of the light guide plates of two picture tubes in a large screen.

On Fig shows the connection of three flat plasma screens.

On Fig shows a section along the AV of Fig 13.

Designations in the figures:

1 - picture tube

2 - horizontal light guide plate

3 - vertical light guide plate

4 - angular light guide plate

5 - raster

6 - phosphor

7 - input ends of the optical fibers

8 - output ends of the optical fibers

9 - light guide

10 - area of the open part of the screen

11 is a compressed image area

12 - matching fibers

13 - characteristic deflecting current line

14 - characteristic deflecting current frame

15 - front glass of the tube

16 - lens matrix

17 - gradan

18 - plasma screen

In the proposed design of a large television screen (FIGS. 1, 2, 3) composed of picture tubes 1, dark stripes appearing on the image are excluded due to the fact that the picture tube dimensions in the screen plane are larger than the sizes of their rasters 5. For this, each Using a kinescope, an electronic scan compresses a small part of the image near the edges of the raster. Light guide plates 2, 3, 4 are superimposed onto this compressed image. They are made of optical guides 9 (Fig. 4) of complex shape with a size of their input ends 7 significantly smaller than the size of the output ends 8. The light guide plate stretches the compressed image and transfers it to the upper ends, which extends to the boundary of the connection of the light guide plates of adjacent picture tubes. As a result, a single image of a television frame is formed on the entire large screen.

Note that it is not difficult to compress part of the image in the large screen, because the lines here are sparse. In a screen made up of K horizontal rows of picture tubes, the number of lines on their screens is K times less than on a television frame.

Consider the operation of the device in detail.

Figure 1 shows a part of a large screen, consisting of 4 picture tubes 1 with light guide plates SP installed on them. In sections AB of FIG. 2 and DS of FIG. 3, sections of vertical 3 and horizontal 2 light guide plates are visible. The design of the light guide plates is visible in FIG. 4 and will be discussed in more detail below. The curved shape of the optical fibers 9 is necessary in order to receive a compressed (in this case, doubled) image a / 2 wide (input region 11) located at the edges of the raster onto the input torps 7 and stretch it to a normal size in the plane of the output ends 8 up to to the border of the connection with the plate of the adjacent picture tube (point O in figure 4).

Figure 5 shows an enlarged one kinescope with light guide plates installed on its screen - four rectangular plates - two horizontal 2 (upper and lower) and two vertical 3 (left and right), as well as 4 small square corner plates 4, located in the corners. All light guide plates are filled with optical fibers 9 (Fig. 4), the input ends 7 of which lie in the plane of the tubes of the picture tubes, and the output ends 8 form the plane of the large screen.

Figure 5 also shows the characteristics of the currents in the deflecting coils of electronic devices in rows 13 U _c = f (t) in frames 14 U _k = f (t), which respectively create a deflection of the light spot in rows and frames. Temporal characteristics are combined with the axes x and y of the light guide plates. Characteristics have a different slope. In the central linear part, the slope of the characteristics is determined by the angle β _c and β _k , at the edges it is half as much and equal to β _{c / 2} and β _{k / 2} , therefore, on the open part of the screen 10 of the picture tube 1, the light spot moves at normal speed, and under the light guide plates at half the speed. As a result, the normal part of the raster is formed on the open part of the screen 10 of the kinescope - the rows are spaced, and under the horizontal, upper and lower plates, the rows are vertically compressed, they are also compressed in square corner plates.

The effect of delayed scanning along rows also leads to the fact that in the vertical left and right plates, as well as in all square plates, the light spot moves with a slowed down speed twice, which leads to the fact that the ends of the lines have a brightness twice as large as in the open part screen.

The light guide plates double the compressed image both in rows and frames. Therefore, the viewer looking at the kinescope sees a normally illuminated open image inside the frame and at the output ends of the light guide plates. The light guide plates are very short and light losses are negligible, therefore, the brightness of the image on the open portion of the screen 10 and on the light guide plates is the same.

If necessary, to increase the brightness of the image on the light guide plates, it is possible to apply to the picture tubes in the interval t _c and t _to (Fig. 5) television signals of larger amplitude.

The height of the light guide plates above the plane of the large screen is negligible (1-2 cm) and does not interfere with the viewer in a large audience. But so that when viewing the image from the side and from a smaller distance, the light guide plates do not reduce the angle at which the image is observed, their height is limited and at the edges of the plates adjacent to the open part of the screen 10, you can enter “matching” optical fibers 12 with the same input sizes and output ends. These fibers “raise” the image due to the plates

In the square corner light guide plates 4, the placement and shape of the light guides are different than in the rectangular plates of FIG. 5. The lower (input) ends of the square plates are located in the small square p, b, m, w, in the plane of the kinescope screen, and the upper (output) ends are located in the plane of the big screen in the large square p’, in ’, m’, w ’. The position of the lower and upper ends is schematically shown in Fig.6. In the plane of the lower ends (p, b, m, w) the image is compressed uniformly in two directions vertically and horizontally. Therefore, the image in this square is not distorted, but reduced. To obtain a normal-sized image, it is necessary to connect the same cells (1-1, 2-2, 16-16) in the lower and upper plane of Fig. 6 with optical fibers.

In square plates, the same types of optical fibers can be used as in rectangular plates. For corner plates, you can apply flexible fibers from the bundles of focons of Fig.4. The optical fibers are combined in sections placed in a certain direction, for example, in the direction of the cells of the plate 13, 14, 15, 16 ’, 9, 10, 11, 12, etc. In the section, optical fibers are mounted on thin plastic plates. A square light guide plate is assembled from the sections. 7 shows a section of optical fibers (13-16). The light guide plate of a simpler design than that shown in FIG. 4 can be made of total internal reflection optical fibers made of plastic and coated with aluminum (FIG. 8).

When installing the examined light guide plates on picture tubes with a thick front glass 15, a lens matrix 16 should be introduced to improve light collection (Fig. 9).

For monochromatic screens it is rational to make fiber-optic plates of optical fibers 9 and gradans 17 (gradient lenses). The height of this design (figure 10) may be several mm. Small diameter gradans are installed at the bottom, they receive light from the phosphor 6 of the tube and transmit it through thin optical fibers to the gradients of the upper row, which have a large diameter. In the plane of the output ends of the upper gradans, a stretched (normal) image is formed.

In this device, as in other large-screen systems, it is important to have good stability of the deflecting systems both in rows and in frames. Therefore, stable forming circuits and amplifiers with negative current feedback should be used. To obtain a scan that provides different speeds of the light spot on the picture tube screen, various formation methods can be used. In particular, a good deflection characteristic can be achieved by adding magnetic zeros of the main deflection tube of the picture tube and a small additional coil through which a current of the required shape is passed.

To improve the collection of light from the phosphor 6 of the tube with a thick front glass 15 and to simplify the design of the large screen, light guide plates made of glass fibers are embedded (the plate can be pressed into the front glass and then sintered with it) in the tubes of the tube so that their outer surfaces make up one plane with the plane of the screen (Fig.11 and 12).

For television, computer technology and show business, flat displays, plasma screens are used 18. Large screens can be created from these devices. 13 and 14 show the connection of three flat plasma screens. On the adjacent edges of the screens, vertical light guide plates are installed, similar to those shown in Figs. 8 and 9. The input ends of the light guide plates are superimposed on horizontally compressed portions of the images located at the edges of the neighboring screens.

The proposed large television screen with a simpler design will improve the quality of the formed image.

Claims (3)

1. A large television screen consisting of picture tubes whose screens are in the same plane, light guide plates overlapping the screen surface, characterized in that the light guide plates are installed along the perimeter of the raster of each of the picture tubes and are formed of horizontal, vertical and angular plates picture tubes are in contact, and the width of the plates is chosen such that it overlaps the part of the raster, which serves a pre-compressed image, the light guide plates are made of light guides with a cross the cross section of the input ends located in the plane of the tubes of the picture tubes is smaller than the cross section of the output ends forming the outer surface of the light guide plates, and at the edges of the plates adjacent to the open part of the screen, with the cross section of the input and output ends identical, the fibers are made curved while the length of the light guides increases in the direction of the light guide plate of the adjacent picture tube. 2. The large television screen according to claim 1, characterized in that the light guide plates are made of optical fibers and optical fibers in the form of gradan. 3. The large television screen according to claim 1, characterized in that the light guide plates made of glass fibers are embedded in the screens of the picture tubes so that their outer surfaces are one plane with the plane of the screen.

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