JPH02186536A - Shadow mask-type color cathode ray tube - Google Patents

Abstract

PURPOSE:To make moire almost unnoticeable by making the lengths of pitches in vertical direction of each slot in row in a shadow mask completely at random order. CONSTITUTION:When longitudinally long slots 6 are ranged in vertical direction having bridges parts 7 between each other and keeping a specified pitch Pv, the length of the pitch Pv in the vertical direction in each row of slots is set completely at random order. As a result, the positions of the bridge parts 7 in each row of the slots become completely at random order in horizontal direction and the shadow of the bridge parts 7 projected to a fluorescent plane also become completely irregular and optical interference between stripes of scanning rays of electron beams alters randomly in each slot row. By this structure, as a whole, moire can be made almost unnoticeable.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a shadow mask type color cathode ray tube,
For details, refer to the shadow mask's electric r-beam passage hole (hereinafter referred to as "
[Prior art] Fig. 2 is a schematic cross-sectional view of a conventional shadow mask type color cathode ray tube.
3 emitted from an electric gun (2) stored in the neck of
The wooden electron beam is deflected by the horizontal deflection magnetic field of the deflection yoke (3) and the eastward deflection magnetic field so as to scan over the entire surface of the fluorescent surface (4), and passes through the corresponding slot (6) of the shadow mask (5). The light impinges on the phosphor stripes of each flower, excites the phosphors and causes them to emit light, forming a color image.

Figure S: The well-known Knot-horn style shadow mask (
It is a partially enlarged view showing an example of 5). Vertical slot (
6) are connected in the vertical direction at a constant pitch [)v through the bridge part (7), and are formed in parallel at a constant pitch in the horizontal direction, and the length of each slot (6) is The open Rono method in the T=direction is constant, and the slot positions of each slot row are formed by even intersecting rj by Pv. When the electric beam is scanned over the bridge part (7) which is the part between the slots 1 to 1 of this slot row and the slot, the electric r beam is 1f14 in this part, so let it be in the fluorescent direction 1.
Part 1. ! 3 is projected in the water direction at a distance of +p H1'l, which is multiplied by the dimensional magnification factor applied to the horn direction. As is well known, the number of scanning lines of the electric beam is 525 in the NTC system, 1) AI, h
The formula specifies 625 trees, and the electric beam also has a certain size, so when the fluorescent surface is scanned, a shadow appears between the scanning lines. Light and dark stripes are emitted. As a result, light and dark stripes caused by the bridge portion (6) of the shadow mask (5) and light and dark stripes caused by the scanning line cause optical interference, resulting in dryness. In order to reduce this dryness as much as possible, the vertical pitch of the shadow mask slots l)v (ll'i) is selected, but this selection is usually made in the next step.

Vertical pitch of the slots of the shadow mask [) projected onto the light surface of v]〆l, 1'vo □ 1) A, scanning line II 11. If the moiré repetition interval (dry arepitch) in the fluorescent direction 1 is 1)II, then the moiré repetition interval in the fluorescent direction 1 is expressed as (1).These can be expressed as: Of the dry group, actually rl 1'
According to the experimental results, the problem with [)2(1
, :3) , l'w (1,4) , l'1l(1
, 5): Three cases: 3, normalized moiré pitch (P.

/Longitudinal direction I1 effective diameter) and L-shaped slot pitch (1'
Taking the case of a color cathode ray tube with a deflection of 3.2 inches as an example, the relationship between Currently, the 1. slot bit is least prone to dryness at 1.28XIOmm, and I)v in this case is 0.91mm. In order to eliminate dryness, it is sufficient to make (l' from the lj formula) A large, but as is well known, the shadow mask needs to be formed into an almost spherical structure, and the forming f1 requires ≦1. It will be about 5mm. In addition, from the perspective of the transmittance of the electric r beam to the shadow mask, it is preferable that l'lV be as compact as possible; To be elected. Furthermore, as shown in Fig. 3, P v≦1.5
Also specify mm and IJI.1. slot bit≦2.1X
In the range of IO-", it is impossible to completely eliminate dryness. Also, the bridge part of the shadow mask (
If the width 13w of 7) is reduced, the moiré will be reduced in the same way as making Pv more attractive, but it is not preferable because of the moldability of the shadow mask, as is the case with making Pv more attractive.
1) Regardless of 4, a certain range of 4+'i is required, and 5 usually requires a planting of 0゜mm≦BWS2.15mm. The size of the shadow of the fluorescence direction due to the influence of the width I3w of the bridge portion (7) becomes as large as the deflection angle of the electron beam. Furthermore, the width of the shadow portion of the scanning line tends to increase as the focusing performance of the electric r beam improves. In particular, in a color cathode ray tube using an electric r-gun, in which a modulation voltage synchronized with the deflection current of the deflection yoke (3) is applied to the focus electrode of the electric r-gun to improve focus characteristics over the entire fluorescent surface. The bright and dark stripes of the scanning line in the direction I become salmon bright, making it easy to stand up. Furthermore, if the shape of the face plate on which the fluorescent surface is formed is an aspherical structure, as is the case recently, the spacing between the scanning lines at each position in fluorescent direction 1 changes, and the pattern of dryness also changes. It becomes a very complicated shape.

[Problems to be Solved by the Invention] As described in 1 above, in the conventional color cathode ray tube of the Sha-Umasuf method, a bridge portion of a finite width is formed between the slots arranged in the vertical direction. (as long as rl+1-, between the striped pattern caused by the scanning line), the 1,000-color difference was unavoidable, no matter how bad it was.

This invention was made to solve the problems mentioned in V.
The purpose is to obtain a color cathode ray tube with no shadow mask.

[Just steps to solve the problem] The shadow mask type 11 color cathode ray tube according to the present invention has a completely irregular ( It is characterized by points set in a random) arrangement.

[Operation] The shadow mask according to the present invention has a completely irregular pitch (1) of the slots in each slot row in the vertical direction.
Since the arrangement is random), the position of the bridge part for each slot row is completely irregular in the water/1ε horn direction, and the shadow projected by the bridge part on the fluorescent surface is also completely regular in the horizontal direction. Since the optical interference between the striped pattern of the scanning line of the electric r beam and the striped pattern of the scanning line changes randomly for each slot row, the overall difference is 1.
11°l, it becomes small.

[Embodiments of the invention] An embodiment of the present invention will now be described with reference to FIG.

In this embodiment, the vertically elongated slots (6) are arranged in a row at a constant pitch in the longitudinal direction via the bridge part (7), as in the conventional example. However, in this embodiment, the vertical pitch Pv of each slot row is set to be completely irregular (random).

To determine the value of Pv for this completely irregular array, a random number generator performs a completely irregular process 1.1. If the vertical pitch Pv for each slot row is randomly determined in this way, a bright and dark striped pattern due to the shadow of the bridge part (7) projected in the fluorescent direction for each slot row and a pattern due to the scanning line of the electron beam will be created. Fine moiré, which is determined by the horizontal slot arrangement pitch, occurs between the bright and dark striped patterns, but because the bangs or the small and random changes occur in each slot row, the overall appearance is very dry. °Becomes less fragile.

In addition, from the viewpoint of the transparency of the electric r beam, Pv≧0.3m
J is preferably as large as possible within the range of m, but from the viewpoint of moldability of the shadow mask, it is better to set the value to 1) ≦1.5 mm. In addition, when forming the fluorescent light direction, by placing a long linear light source in the longitudinal direction of the slot of the shadow mask and exposing it, the effect of the shadow of the bridge part of the shadow mask is eliminated and the light is continuous in the vertical direction. It is well known that striped fluorescent surfaces are formed by photolithography, but when determining the exposure conditions, it is undesirable for the range of 1) 9 to be too wide. 3. Shikarun, the 1 mentioned before
, in the range of 5mm≧Pv≧0.3mm, by performing exposure while reciprocating the linear light source in the direction of the long hairs, continuous stripe-like fluorescence is produced in the vertical direction using conventional photolithography technology. It was experimentally confirmed that it is possible to form a surface.

〔Effect of the invention〕

As described above, according to the present invention, the vertical slot pitch Pv of each slot row of the shadow mask of the shadow mask type color cathode ray tube is set to rung t\, so that the shadow mask is projected in the direction of the fluorescent light. The shadow of the bridge section and the ttr-
Since the optical 1' cross-over between the beam and the scanning line varies minutely for each slot row, the shadow mask type color cathode ray reduces the occurrence of shadow rays as a whole and can reproduce very high quality images. There is an effect that the tube can be obtained.

Furthermore, if the slot pitches of the rows are the same and the pitch of each slot row is random, it will be easier to produce patterns for photolithography than if the slot pitch is random regardless of the slot row. It also has the effect of making it easier.

[Brief explanation of the drawing]

FIG. 1 shows a shadow mask according to an embodiment of the present invention.
・Figure 2 is a schematic cross-sectional view of a shadow mask type color cathode ray tube, Figure 3 is a partially enlarged view of a conventional shadow mask, and Figure 4 is a small diagram of a dry area. be. (1)...Shadow mask type color cathode ray tube. (5)...Shadow mask, (6)...Slot, (7)...Bridge part. <) In each figure, are they the same? ] The bow indicates the same or +1 part.

Claims (1)

[Claims] (1) A shadow mask in which three in-line electron guns and vertically elongated slots are arranged in parallel in the horizontal direction at a constant pitch P_v; In a shadow mask type color cathode ray tube having a striped fluorescent surface continuous in the vertical direction, the vertical pitch (P_v) of the slots in each slot row is set to 1.5≧P_v≧0.
．． 3. A shadow mask type color cathode ray tube, characterized in that the color cathode ray tube is formed in a completely irregular arrangement within the range of 3.