JPS583581B2 - cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube for color television, and more particularly to a spacing between mask display surfaces of a cathode ray tube having a corrugated shadow mask.

In a shadow mask cathode ray tube that generates color images, a plurality of focused electron beams impinge on a mosaic fluorescent display screen through a color selective shadow mask having a large number of apertures.

The path of the beams through the mask is such that each beam impacts and excites only one type of color-forming phosphor on the display surface.

In conventional cathode ray tubes, a portion of each of the three electron beams passes through one aperture in the mask and bombards each adjacent phosphor element of the same phosphor triplet on the display surface.

The interval between the mask phosphor screens of such a cathode ray tube is called the primary interval.

The dimensions in this case are given by the following equation.

Here, q is the distance between the mask and the display surface, L is the distance between the deflection center and the display surface, a is the distance between adjacent apertures in the mask, and S is the distance from the tube axis of the electron beam at the deflection center.

A typical 25V 100 DEG cathode ray tube having a linear fluorescent display screen and an in-line electron gun has a spacing q between mask display surfaces of about 16 to 18.5 mm, measured along the tube axis.

``Journal of the S.S.'' published in July 1952.
M●PTE (Journal of t
he SMPT. E)” Volume 59 Kaplan (S-H-
Kaplan's paper [Parallax Barrier Theory
At the beginning of ``Of Parallax Barrier'', the possibility of higher-order mask display surface spacings to which the above formula is no longer applicable is discussed.

At even higher order spacings, triplet phosphor elements in the display surface are excited by electron beams passing through different mask apertures, but the Kaplan article does not discuss the benefits of using higher order spacings.

In fact, to date, higher order mask display surface spacings have not been known to be commercially available.

On the other hand, US Pat. No. 3,282,691 describes a printing method for a color television fluorescent display screen in which a light source is arranged at the center of a higher order color than the first order.

Although commercial tubes have been manufactured using this method, no commercial tube is known that is configured to operate an electron beam at a higher order color center.

A recent modification of the shadow mask picture tube design has been suggested in U.S. Pat. Apertures are arranged.

The spacing between the rows of apertures within this tube can be changed to some extent in proportion to the horizontal change in the spacing between the mask and the phosphor screen.

Because of this permissible variation, the aperture (inter-row) spacing a can vary by a factor of two across the mask, but the aperture width must also vary by a factor of two to maintain proper electron passage.

Such wide variations in aperture dimensions and matrix apertures remain problematic in shadow mask etching and matrix printing, as it becomes difficult to maintain the required accuracy if the values vary too much. There is.

The present invention overcomes these etching problems associated with the formation of wave masks by using higher order mask locations in cathode ray tube designs.

In the cathode ray tube according to the present invention, the spacing between the corrugated shadow mask and the display surface and the spacing between the apertures in the shadow mask are such that each portion of the different electron beams passing through the different apertures can cause the same triplet fluorescence on the display surface to be generated. Adjacent ones of the body elements are set to be excited.

The present invention will be described in more detail below with reference to the accompanying drawings.

FIG. 1 shows a vacuum glass envelope 20 consisting of a rectangular panel or cap 22, a neck 24, and a funnel 26.
A conventional rectangular cathode ray tube 18 is shown.

The panel 22 consists of a display face plate 28 and a peripheral flange or side wall 30 sealed to the funnel part 26, and a mosaic three-color fluorescent display surface 32 is formed on the inner surface of the face plate 28.

The display surface 32 is a linear display surface consisting of a parallel array of elongated linear phosphor elements substantially parallel to the vertical axis of the tube, that is, perpendicular to the high frequency scanning direction.

The area between each linear phosphor element is filled with light absorbing material.

A wave-shaped color selection electrode, ie, a shadow mask 34, having a large number of apertures is detachably attached to the display surface 32 at a predetermined distance therebetween.

In the mask 34, the parallel wave crests extend vertically and the corrugations extend horizontally, and the apertures in the mask 34 are vertically arranged slits in rows parallel to the wave crests.

As schematically shown in FIG. 1, an in-line electron gun 36 is installed within the neck portion 24, and three electron beams 38B
, 38R, and 38G are generated and irradiated onto the display surface 32 along a coplanar focused path passing through the mask 34.

FIG. 2 shows a color picture tube 40 using one embodiment of the present invention.
shows.

For ease of identification, the same reference numerals are used for components similar to those of the conventional picture tube 18, and different reference numerals are used only for changed parts.

The first difference between this picture tube 40 and the conventional picture tube 18 is the spacing between the mask and the display surface.

That is, the mask 42 of the picture tube 40 is located at a significantly longer distance from the display surface 32 than the mask 34 of the picture tube 18.

Increasing the distance between the mask and the display surface in this manner can be referred to as placing the mask 42 at a secondary or higher-order position with respect to the display surface 32.

At this higher order position, the spacing of the aperture rows and the aperture width change with respect to the first order position.

Conceptual diagrams of a configuration with increased spacing are shown in FIGS. 3 and 4.

3 and 4, the positions of the phosphor elements forming the display surface 32 are the same, but the external beams B, R
The arrangement of is reversed.

In each figure, the mask is shown in multiple locations that can perform color selection functions.

The arrangement of electron guns corresponding to even-numbered positions and the arrangement of electron guns corresponding to odd-numbered positions are reversed.

In each figure, the available mask positions are represented by solid lines, and the mask positions for the opposite electron gun array are represented by dotted lines.

Mask position 1 in FIG. 4 shows the primary mask position of the corrugated mask of the conventional cathode ray tube. Bombard each adjacent three phosphor elements of the phosphor.

The triple phosphor set shown in the figure consists of three phosphor elements arranged adjacently so that the central electron beam hits each central phosphor element.

At even higher order mask positions, various embodiments of the invention ensure that each portion of the electron beam that impinges adjacent phosphor elements does not pass through the same aperture, but always passes through different apertures.

The first possible high-order mask position is shown in FIG. 3 as position 2.

When the mask is placed in position 2, the electron gun arrangement is the same as in the conventional method.
It should be noted that the case of the next mask position is reversed.

In order to make the position and size of the phosphor elements on the display screen the same, it is necessary to change the mask opening size and spacing at position 2 from those when the mask is placed at position 1.

In other words, the apertures in the mask become slightly thinner and the distance between them becomes narrower.

Due to this change, the aforementioned dimension equation q=La/38 no longer holds true, and the equation for the example at position 2 becomes as follows.

If the dimensions of the cathode ray tube are determined in this way, the two outer beams R and B that impact the outer two phosphor elements in the same three-piece phosphor set will be the central part that impacts the central phosphor element. passes through an aperture next to the aperture through which a portion of the beam G passes.

Position 3 is a secondary mask position where, like position 2, the arrangement of the electron guns is reversed.

Again, the two outer beams impinging on a particular phosphor triplet on the display surface pass through apertures next to the aperture through which the central beam passes.

Although mask positions 2 and 3 are called secondary positions (in which case the center beam passes through an aperture next to the aperture through which the outer beam hits a particular triplet phosphor), The distance between the mask and the display surface differs significantly between the two.

This difference is made clear by the following equation at position 3.

q=4La/3S The tertiary mask position is such that the aperture through which the central beam that hits a 3-piece phosphor passes is two spots away from the aperture through which the outer beam that hits the same 3-piece phosphor passes. It's the location.

In other words, the tertiary position is a position where the outer beam that has passed through the same aperture as the central beam hits another 3-piece phosphor that is two spaces away from the 3-piece phosphor that the central beam hits. be.

One example of a tertiary position is shown at position 4 in FIG.

The dimensional equation in this case is as follows.

Another example of a tertiary position is shown at position 5 in FIG.

The dimensional equation for this example is:

Although it is not very desirable to have a mask, display surface, and electron gun assembly whose positional relationship is tertiary or higher, it is possible.

The fourth position is position 6 in Figure 3 and position 7 in Figure 4.
are shown respectively.

The dimensional equation of the mask at position 6 is as follows.The dimensional equation of the mask at position 7 is as follows.

Looking at the quadratic and higher order position equations, it can be seen that the following general dimensional equations are obtained:

Here, n is an integer greater than 1 excluding multiples of 3, i.e. 2
,4,5,7,8,10,11,13,1416,...
・It is.

Although FIGS. 3 and 4 have been described assuming that the phosphor elements forming the display surface have the same display surface arranged in the same orientation, two phosphor elements on the outside of each triple phosphor set It is clear that it is also possible to exchange the electron beam orientation and leave the electron beam orientation in the first-order conventional configuration.

As mentioned above, in the recently suggested cathode ray tube, the aperture spacing a is slightly changed in proportion to the change in the mask-to-phosphor screen spacing q.

It can be seen that by utilizing the idea of increasing the absolute value of q of this invention, it is possible to reduce the change in a even with non-uniform changes in q, as in the case of a cathode ray tube with a wave mask. .

For example, in a conventional cathode ray tube, the distance q is 16
mm, and 18.5 mm at other points, the ratio of the distance q between these two points is 1.16.

However, if we assume that there is a change of 2.5 mm between two points and increase the absolute value of q, the distance q at the first point will be 32 mm, and at the second point the distance q will be 34.5 mm. The ratio is 1.08.

Therefore, since the interval a changes in proportion to the change in the interval q,
The change in spacing a is reduced from approximately 16% to 8%.

The Kaplan paper mentioned above suggests the possibility of using higher order mask positions than second order in cathode ray tubes with flat or spherical masks, but does not say anything about the advantages of such a mask arrangement. Not recognized.

In fact, to date no advantage has been found in the use of higher order mask positions than second order.

However, the present invention provides novel results hitherto unknown to those skilled in the art of cathode ray tube manufacturing due to the unique combination of a second order or higher order mask arrangement and the wave mask concept.

The advantage of this is that varying the aperture width is simplified so that the required tolerances of commercial quality cathode ray tubes can be maintained using current mask etching techniques.

[Brief explanation of drawings]

FIG. 1 is a plan view of a conventional cathode ray tube with a corrugated shadow mask. FIG. 2 is a plan view of a cathode ray tube similar to FIG. 1 using one embodiment of the present invention. FIG. 3 is a schematic diagram showing various mask positions with respect to the display surface and the incidence of each part of the three electron beams. FIG. 4 is a schematic diagram showing various mask positions with respect to the display surface when the outer red and blue electron beams in FIG. 3 are reversed. 18,40...Cathode ray tube, 32...Fluorescent display screen, 34,42...Shadow mask, 3
8...Electron beam.

Claims (1)

[Claims] 1. This mask includes a display surface formed by arranging three sets of vertically elongated phosphor elements that emit light of different colors, and a corrugated porous shadow mask with parallel longitudinal waves attached adjacent to the display surface. is separated from the display surface at a mask position higher than the first order, and adjacent ones of the same triple phosphor elements on that display surface are excited by different electron beams passing through different apertures in the mask. A cathode ray tube characterized in that the cathode ray tube