JPS61237340A - Assembling method for shadow-mask - Google Patents

Abstract

PURPOSE:To position and adjust the shadow-masks simply and in a high accuracy, by positioning them through detecting the variation of light quantity passing through the main mask and the submask. CONSTITUTION:When the light 15 radiated from a light source 11 passes through the opening 70 of a subshadow-mask 30, then through the opening 7 of the main shadow-mask 3, and goes into a light detector 12, an output indicator 14 displays an index value proportional to the quantity of the incident light. The figure a shows the case when the centers of the openings 70 and 7 are not at the same point, and the passing light 20a through he opening 7 has a lack, making the light quantity 21 smaller than the maximum value. On the other hand, the figure b shows the case when the centers of the openings 70 and 7 are almost at the same point, and the passing light 20b through the open ing 7 has no lack, making its quantity 22 maximum. Therefore, if the main shadow-mask 3 is positioned to show a maximum value of the output indicator 14, the centers of openings 70 and 7 are almost coincide. Such a positioning is carried out one by one at the positions selected adequately, and the main shadow-mask 3 is fixed at the position to be the best position as the whole shadow-masks, and welded at the frame.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for assembling a shadow mask assembly having two main and sub shadow masks.

[Conventional technology]

FIG. 4 is a schematic cross-sectional view showing the structure of a conventional general color cathode ray tube. αQ is made of glass pulp, and the inside of its front surface is coated with a phosphor screen (1) consisting of three-color phosphor dots or stripes that emit red, green, and blue colors. (3) is a shadow mask placed at a predetermined distance from the phosphor screen (1), and has a large number of apertures (7) formed in a predetermined shape at a predetermined position.
) and is fixed to the frame (6) by welding.

(4) is stored in the rear neck of the glass bulb αq.
:ill subgun, (6R), (5G).

(5B) are red, green, and blue electron beams emitted from the electron gun (4), and (2) is the electron beam (
5R), (5G), and (5B) are this deflection yoke (2
) is deflected by the magnetic field of the shadow mask (3), passes through the aperture (7) of the shadow mask (3), and strikes each of the eight color phosphors of the phosphor screen free layer (1), projecting an image on the phosphor screen (1). do. In the diagram, L is the axis! , 0 is the deflection point from which the electron beam can be considered to be radiated.

Figure 5 shows the phosphor screen (1) and shadow mask (3).
] is a partially enlarged view. In Fig. 5, red phosphor dots (IR), green phosphor dots (IG), and blue phosphor dots (IB) are coated on the inside front surface of the glass bulb αQ, and a phosphor screen (1 ) is formed.The fluorescent screen (1) and a predetermined distance D1 are formed.
The opening of the shadow mask (3) provided at
7) and 8-color phosphor dots (IR), (IG), (
IB) are arranged in a predetermined geometrical relationship; for example, the electron beam (5R) corresponding to the red phosphor dot (IR) passes through the aperture (7) of the shadow mask (3). (51R) and hits only the red phosphor dot (IR), which excites it and causes it to emit light.

Conventional color cathode ray tubes are constructed as described above, but when the flow rate of the electron beam is extremely large, such as in the highlight area, the shadow mask (3) is heated by the electron beam and causes thermal deformation. As shown in FIG. 5, the shadow mask (3) is displaced to the position shown by the broken line, and the distance between the phosphor screen (1) and the shadow mask (3) is D2.
Changes to Therefore, eight color phosphor dots (IR),
The geometric relationship between (IG), (IB) and the aperture (7) of the shadow mask (3) also changes, so that the electron beam (6R) passes through the aperture (7) of the shadow mask (3).
) has a different trajectory from the trajectory (51R) of the electron beam before the thermal deformation of the shadow mask (3), and does not accurately hit the red phosphor dot (IR) as shown by the trajectory (52R).
Other phosphor dots, such as green phosphor dots (IG) in the example shown in FIG. 5, also hit, causing a problem of color shift.

In order to eliminate such problems, a color cathode ray tube equipped with a sub shadow mask has been devised. Figure 6 is a cross-sectional view of a color cathode ray tube equipped with a sub shadow mask, showing the main shadow mask (3). In addition, a sub-shadow mask is provided. This sub-shadow mask is attached to the frame (6) on the electron gun (4) side of the main shadow mask (3) at a predetermined interval, and as shown in Figure 7, it has eight color phosphor dots. (IR), (IG)
, (IB) and the main shadow mask (3 holes (7)
and the aperture (70) of the sub-shadow mask are arranged in a predetermined geometrical relationship. The area of the aperture (70) of the sub shadow mask is the area of the main shadow mask (3
) is formed to be larger than the area of the opening (7) by a predetermined amount.

With a shadow mask configured in this way, even if the secondary shadow mask is thermally deformed by the electron beam (5R) in the highlight part of the image, for example, most of the energy of the electron beam (5R) is absorbed by the secondary shadow mask. Shadow mask (
′:! Since it is absorbed by A, the main shadow mask (
The energy of the electron beam (58R) hitting the main shadow mask (3) becomes extremely low, and the main shadow mask (3) does not undergo thermal deformation, or even if it does, the amount of displacement is extremely small. Therefore, no color shift occurs.

On the other hand, the thermally deformed secondary shadow mask is displaced to the position shown by the broken line in FIG.
Although the trajectory changes as shown in the figure compared to fζ, the area of the aperture (70) is larger than the area of the aperture (7), so
The electron beam passes through the aperture (7) without chipping, hits only the corresponding red phosphor dot (IR), and hits the other green phosphor dot (IG), as shown by the trajectory (55R).
Since the light does not hit the blue phosphor dots (IB), no color shift occurs.

[Problems to be Solved by the Invention] In manufacturing the color cathode thin tube that uses the sub-shadow mask-tH as described above, the main shadow mask (3) and the sub-shadow mask (31jl) are placed on the frame (6) in advance. The openings (7) and (To) must be aligned and fixed with high accuracy over the entire surface.

However, with general mechanical positioning methods, there is a problem in that it is extremely difficult to perform the above positioning with a predetermined accuracy.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a method for accurately and easily assembling a main shadow mask and a sub-shadow mask.

[Means for Solving the Problems] The present invention is characterized in that one of the main and sub shadow masks is fixed to a frame, and the other shadow mask is held on the frame so as to be movable in the plane direction at predetermined intervals. , on the expected trajectory of the electron beam passing through both apertures of both shadow masks, a light source that sandwiches both shadow masks and emits a light beam along the same optical path as the predicted trajectory; A light m+detecting photodetector is arranged,
The movable shadow mask is positioned so that the sum of the amount of transmitted light at a plurality of preset positions on the surface of the shadow mask is maximum or the weighted evaluation value is the best, and then the shadow mask is This is an assembly method in which it is fixed to the frame.

[Effect]

The assembly method of the present invention detects changes in the light source passing through the main/adverbial mask 8 and performs positioning, so positioning and matching can be performed extremely easily and with good stacking.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing an example of the configuration of a one-time apparatus for carrying out the present invention. In the figure, the secondary shadow mask is welded to the frame (6) in advance, and the main shadow mask (3) is installed on the front side with a predetermined distance from the secondary shadow mask. June ζ is not yet fixed by welding and can be moved freely up, down, left and right.The light source (11) is installed at the position corresponding to deflection point 0, and this light source (on the opposite side A photodetector (+21) is installed at a predetermined position on the front side of the main shadow mask (3).The output of the photodetector (!) is amplified by a predetermined amount by an amplifier (α).

The output is displayed by an output indicator (14).

Next, a positioning method using this device will be explained.

The light (IQ) emitted from the light source (11) passes through the aperture (70) of the secondary shadow mask, and then passes through the aperture (7) of the main shadow mask (3) and reaches the photodetector α. incident.

The output display meter α displays an indication value proportional to the amount of light incident on the photodetector (121).
) to explain the relationship between the position of the aperture (70) and the amount of light passing through, Figure (3) shows the case where the centers of the aperture (70) and the aperture (7) are misaligned; ) passing light (20a)
There is a chip, and the luminous intensity circle is smaller than the maximum value.

7: The same figure (b) shows the case where the centers of the aperture (70) and the aperture (7) almost coincide, and there is no chipping in the light (20b) passing through the aperture (7). , its light weight (4 is the maximum value. Therefore, if the main shadow mask (3) is aligned so that the displayed value of the output display meter α becomes the maximum, the aperture (70) and the aperture ( 7) will almost coincide.

This alignment work is performed one after another on appropriately selected parts, such as the center of the shadow mask surface, and the four intermediate parts between the center and the four corners, until the entire shadow mask surface is aligned. The main shadow mask (3) is fixed at a position considered to be best and welded to the frame (6). If the position and shape of each hole (7), (70) of the main/adverbial shadow mask (3), G30) is formed as designed, there will be at least two holes (7), (7G). If the positions of the holes are aligned, the positions of the openings on the entire surface of the shadow mask should also match. However, since there are variations in the positions and shapes of the apertures (7) and (70) formed in the actual shadow mask, alignment is performed at multiple locations as described above, and the position-based weighting evaluation is performed. You need to select the file that you think is the best. Performing such work using one photodetector α'4 not only takes a long time, but also makes it extremely difficult to align it to the best position.

FIG. 8(a) is a diagram illustrating another example of the configuration of a γ-coupling device implementing the present invention, which solves the above-mentioned problems. In this example, five photodetectors (12a) to (121) are arranged at the center part of the shadow mask surface and four peripheral parts between the center part and the corner parts, as shown in FIG. 8(b). The detection signals of these photodetectors (12a) to (12e) are assigned a large weight to the detection value of the central photodetector (12b), and the other four The detection values of the photodetectors (12a), (12c) to (12e) are amplified by reducing the weighting, and the added value is displayed on the output display (I4).

When using this device, if the main shadow mask (3) t is positioned so that the display value of the output display α is maximized, the main shadow mask (3) t will be at the best position for the entire shadow mask surface. ) It is sufficient to fix it in the position of t and weld it to the frame (6).

In this way, the main shadow mask can be quickly and accurately aligned, and the shadow masks that form the main and sub shadow masks can be assembled quickly and accurately.

As explained above, 7: In the embodiment, the end of the sub-shadow mask is fixed to the frame (6), and the main shadow mask (3) is moved to perform alignment, but the reverse may be used.

In addition, although we have explained an example in which the light source (11) is installed at the deflection point of the electron beam, if the light source (11) is on the expected trajectory of the beam passing through the apertures (7) and (70), it can be placed on either side of the shadow mask. However, it can be placed in any position, and the number is not limited to one. It goes without saying that the photodetector should be installed on the opposite side from the light source.

〔Effect of the invention〕

As described above, according to the invention of B, the positioning and matching of the main shadow mask and the sub shadow mask is carried out by placing a light source on the front and rear sides of both shadow masks, and installing a photodetector on the opposite side. The photodetector is fixed to the frame at the position where the detection value is maximum.1 This has the effect of quickly and accurately assembling a shadow mask having two main and sub shadow masks. .

[Brief explanation of drawings]

Fig. 1 shows an example of the configuration of an apparatus for carrying out the present invention, Fig. 2 shows the relationship between the positional relationship of the apertures of the main/adverbial shadow mask and the amount of light passing through it, and Fig. 8 (a) FIG.
b) is a diagram showing the arrangement position of the photodetector, FIG. 4 is a schematic cross-sectional view of a conventional color cathode ray tube, FIG. 5 is a partially enlarged view of the phosphor screen and shadow mask in FIG. 4, and FIG. 6 7 is a schematic sectional view of a color cathode ray tube with a main shadow mask and a sub shadow mask tV, and FIG. 7 is a partially enlarged view of the phosphor screen and the main/adverbial shadow mask in FIG. (3)...Main shadow mask, (6)...Frame, (7)...Aperture of main shadow mask, (! Leaf...Light source, (121, (12a) to (12e)...・Light emitter, H...Output indicator, ('!A...Sub shadow mask, (70)...Aperture of sub shadow mask. In addition, in the figures, the same symbols are the same or A considerable portion is shown.

Claims (1)

[Claims] (1) Either one of the main and sub shadow masks is fixed to the frame, and the other is movable in the plane direction and held at a predetermined interval, and the electron beam passing through the front or rear shadow masks is A light source disposed on the predicted trajectory and a photodetector disposed on the opposite side of the light source to detect the amount of light passing through both of the shadow masks are provided, and the sum of the amounts of light passing through multiple parts of the shadow mask surface is provided. A method for assembling a shadow mask, in which the position of the movable shadow mask is adjusted so that the evaluation value is maximized or the evaluation value weighted by position is the best, and then the shadow mask is fixed to the frame.