JPH021339B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube used for displaying television images, and provides a cathode ray tube that can improve the raster density of images projected on a phosphor screen. .

Recently, advances in cathode ray tube manufacturing technology and circuit technology have improved the focusing state of electron beams, making it possible to irradiate a fluorescent screen with an electron beam having a small spot diameter. Along with this, it has also been possible to improve the horizontal resolution by widening the frequency band of the applied video signal. However, in conventional cathode ray tubes, the phosphor screen is scanned with only one electron beam, so as the spot diameter becomes smaller, a non-emitting part is created in the middle between horizontal scanning lines. The disadvantage is that the image appears coarse in the vertical direction.

In view of this, the present invention provides a cathode ray tube that can increase the apparent number of horizontal scanning lines in the vertical direction and improve the vertical density of the image even if the spot diameter of the electron beam becomes small. The purpose is to

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings showing one embodiment implemented in an in-line color cathode ray tube. Figure 1 shows the schematic structure of its main parts.
FIG. 2 shows the focused state of the electron beam, and FIG. 3 shows the displayed state of the horizontal scanning lines on the fluorescent screen. In the figure, 1R, 1G, and 1B are cathodes that emit electrons, and 2 to 5 are cathodes that emit electrons, and electrons 2 to 5 are drawn out from cathode 1, focused by an electron lens, and further accelerated to become electron beams 6R and 6.
G, 6B to collide on the phosphor screen.
~The fourth grid. In this embodiment, each grid 2 to 5 has electron beams 6R, 6G,
Passing holes 7R to 10R, 7 for passing through 6B
G~10G and 7B~10B are provided, and two passing holes are provided at a constant interval in the vertical direction, so that the electron beams 6R, 6G, 6B are provided.
Two lines are formed in the vertical direction.
When the electron beams 6R, 6G, and 6B formed in two vertical directions collide with a phosphor screen, two beams separated vertically are formed on the phosphor screen as shown in Figure 3. horizontal scanning lines can be displayed simultaneously. In FIG. 3, "a" reduces the prism effect generated between the third grid 4 and the fourth grid 5 to form two electron beams 6R and 6.
The state when the interval between G and 6B is made smaller and the interval l between the scanning lines displayed at the same time is made smaller;
This is the state when the interval between G and 6B is increased and the interval L between the scanning lines displayed at the same time is increased. In the diagram,
A, B,... are the first line, second line...
A', B', . . . are the horizontal scanning lines of the first line, second line, . . . when interlaced scanning is performed.

As can be seen from Figure 3, this cathode ray tube reduces the apparent number of horizontal scanning lines in the vertical direction to 2
In other words, the image density in the vertical direction can be doubled compared to the conventional image density, and the apparent density of the image can be significantly improved.
Therefore, even if the spot diameters of the electron beams 6R, 5G, and 6B are made smaller, the roughness of the image will not be noticeable. It is possible to improve the definition of images and display beautiful images.

In the above embodiment, two electron beam passing holes are provided in each vertical direction to form two electron beams in each vertical direction, but it goes without saying that the number may be further increased. Nor.

As described above, according to the present invention, two or more horizontal scanning lines separated in the vertical direction are simultaneously displayed on the phosphor screen, thereby improving the vertical direction of the television image displayed on the phosphor screen. It is possible to increase the apparent horizontal scanning lines, improve the vertical density of the image, and realize a useful cathode ray tube that can project beautiful images with high definition.

[Brief explanation of drawings]

FIG. 1 is a perspective view of essential parts of a cathode ray tube according to an embodiment of the present invention, FIG. 2 is a sectional side view thereof, and FIGS. 3a and 3b are front views of a phosphor screen showing its display state. 1R, 1G, 1B...Cathode, 2-5...1st
~4th grid, 6R, 6G, 6B...Electron beam, 7R~10R, 7G~10G, 7B~10
B...Electron beam passage hole.

Claims (1)

[Claims] 1 A cathode that emits electrons, and a plurality of grids that extract, focus and accelerate electrons from the cathode and impinge on a phosphor screen as an electron beam, and at least one of the grids is spaced vertically. Two or more electron beam passing holes are provided at intervals to form two or more electron beams in the vertical direction, so that two or more horizontal scanning lines separated in the vertical direction are simultaneously displayed on the phosphor screen. A cathode ray tube characterized by: