JPS5927058B2 - Cathode ray tube manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention has a screen made of a mosaic-like structure of fluorescent dots that emit light in three colors of red, green, and blue when an electron beam strikes the screen, and is arranged at a predetermined distance from the screen. The present invention relates to a method for manufacturing a cathode ray tube in which the position of the electron beam reaching the screen is determined by a shadow mask or grid electrode (hereinafter collectively referred to as shadow mask).

A typical example of the cathode ray tube is a shadow mask type color picture tube, and the shadow mask type color picture tube will be explained below with reference to the drawings.

As shown in Figure 1, a conventional shadow mask type color picture tube has a neck part 1 containing an electron gun, and a funnel part 2.
and a dish-shaped face plate 3, and on the inside of the dish-shaped face plate 3 are phosphor dots (including stripes in the present invention) 4 coated in a regular mosaic-like batten structure and a metal back covering the entire dots. 5 and a shadow mask γ.

The shadow mask 1 is held at a predetermined distance from the screen by a shadow mask holding pin stud 8 and a shadow mask holder 9 attached to the inner surface of the face plate.

The electron beams passing through the holes (or slots) of the shadow mask 7 must correctly strike the corresponding phosphor dots 4 on the screen, so the positional relationship between the shadow mask 7 and the screen must be very precisely determined. Must be retained.

For this reason, in manufacturing conventional shadow mask type color picture tubes, the dish-shaped face plate 3 and the shadow mask 7 are assembled in pairs using the mask holder 9 in advance.
Then, a phosphor suspension is applied to the inner surface of the dish-shaped face plate 3, and a light beam from an exposure device as shown in FIG. The trajectory of the electron beam was approximated by a correction lens 11, and the phosphor dots 4 were created by burning through a shadow mask 1.

According to this method (hereinafter referred to as the pair method), the accuracy of assembling the shadow mask γ opposite the face plate 3 is approximately ±0.5 in the tube axis direction, and ±0.5 in the X-Y direction of the screen perpendicular to the cage tube axis. A thickness of about 1 mm is sufficient, and this can be easily achieved with current assembly technology.

Even if the shadow mask 7 is assembled with a slight deviation from the face plate 3, the phosphor dots 4 can be printed by exposure using a pair of the face plate 3 and the shadow mask T. In the case of a finished product, the position of the electron beam that has passed through the hole in the shadow mask 7 and the screen does not have a large error with respect to the position of the dots, so that correct operation can be performed.

However, the drawbacks of the pair method are: 1. When making a screen, you need to put on and take off the shadow mask about 6 to 7 times (one time for taking it off and putting it on).
must be performed (counted as times).

2. Attaching and detaching the shadow mask is a task that requires extremely delicate control, making it difficult to automate and requiring manual labor by skilled workers.

3. Occurrence of deformation of the shadow mask due to attachment/detachment work is unavoidable.

Also 4. The reproducibility of the position of the shadow mask upon attachment and detachment is very important, and an accuracy of 0.005 mm or less is desired, but this is not always satisfactory.

5. There were other things. For this reason, a manufacturing method called the so-called master shadow mask method has been considered for the purpose of greatly simplifying the process and saving labor.

In this method, a dedicated master shadow mask is used to manufacture the screen, and then the finished product shadow mask and face plater are assembled and fixed to be incorporated into the finished product, and until the screen is manufactured, the finished product shadow mask and (pairs) are not assembled, so the process involves only the dish-shaped face plate, and since there is no process for attaching and detaching the shadow mask, almost no human labor is required, making it possible to produce a manufacturing method that is close to full automation.

Next, a general example of the master shadow mask method will be described. The shadow mask for finished products and the master shadow mask for screen production use the same hole device.

These shadow masks have reference holes for positioning the screen in a subsequent process.

That is, the phosphor dots 4 on the screen are exposed by an exposure device having a built-in master shadow mask 12 as shown in FIG.
At the same time, a reference dot is printed on the inner surface of the face plate through the reference hole.

In the process of assembling the product shadow mask 7 to the face plate 3, for example, as shown in FIG. A microscope 14 for observing a light spot passing through a reference hole with respect to a shadow mask positioning mechanism 13 that can be moved to a reference driver l-4' and a shadow mask 7 are attached to a shadow mask fixing stud (not shown) of the face plate 3. Device for fixing to (
After positioning the shadow mask 1 with the microscope 14 using a shadow mask/face plate assembly device (not shown) so that the light spot passing through the reference hole of the shadow mask 7 coincides with the reference dot 4', The shadow mask 1 is fixed to the shadow mask fixing stud of the face plate 3.

In this method, the printing of the reference dots 4' is performed using the same light source as used for printing ordinary phosphor dots, so the printing strength of the reference dots is insufficient, and as a result, the dots do not have a constant shape. Adjustment of the light source device, etc. may result in insufficient reference dots being obtained because there are no or no links, and it is difficult to clearly observe the light point when positioning the shadow mask. Shadow mask positioning accuracy is required due to easy errors etc. ±0.0
0.05 mm or less, only about ±0.02 mm was obtained, and it was not possible to obtain the same quality as the pair method described above.

The present invention improves the drawbacks of the master shadow mask method described above, provides a method for combining the positioning of a face plate and a shadow mask with high accuracy, and enables automation and labor saving of screen production, which are the advantages of the master shadow mask method. It is something to do.

Next, the manufacturing method according to the present invention will be explained using a method of manufacturing a shadow mask type color picture tube using flat glass as a face plate.

FIG. 5 shows a color picture tube manufactured by the manufacturing method of the present invention. The face plate 17 is composed of a neck part 15 housing an electron gun, a funnel part 16, and a face plate 17. A phosphor is provided on the inner surface of the face plate 17. The screen is configured.

The shadow mask 18 has a box-shaped peripheral portion, and a plurality of shadow mask holders 19 are attached to the peripheral portion.

The shadow mask 18 has a large number of through holes arranged in a regular arrangement, and a plurality of reference holes 20 are formed outside the outermost edge of the through hole surface.

The shape of the reference hole 20 may be round, square, or, for example, cross-shaped. A fixing stud 21 for fixing the mask holder 19 is attached to the inner surface of the face plate 17 at a position facing the mask holder 19. .

A phosphor screen according to this method is produced by the following steps.

First, a phosphor retentate liquid of a first luminescent color is uniformly applied to the inner surface of the face plate and dried to form a phosphor coating film.

Next, this face plate 1.7 is accurately positioned and mounted on the exposure apparatus shown in FIG.

This exposure device has a light source 2 located near the center of deflection.
1 and correction lens 22 and master shadow mask 23
The light beam passing through the light-transmitting portion of this master shadow mask 23 photosensitively solidifies a predetermined portion of the phosphor coating film.

At the same time, parallel rays of light in the perpendicular direction are transmitted through a plurality of reference holes 24 formed in the master shadow mask 23 to the surface of the master shadow mask placed at positions corresponding to the respective reference holes 24. A reference dot 26 is printed on the face plate 17 by the light beam emitted from the light source device 25.

This light source device has a light source 2 that burns the effective diameter of the screen.
Adjustments are made so that the reference dots 26 are printed firmly and clearly independently of the reference dots 1.

After that, the faceplate is developed and the unexposed areas are washed away.

This process is repeated for the second and third luminescent color phosphors.

In these cases, it is not necessary to bake the reference dots.

A shadow mask as shown in FIG. 1 is applied to the face plate N7 having the phosphor screen thus formed.
Assemble the finished product shadow mask 1B using a face plate assembly device.

The shadow mask/face plate assembly device for finished products supports a light source device 27 and a shadow mask 1-8, which are disposed at positions corresponding to the reference holes 20 of the shadow mask, respectively, like the exposure device, and supports X-Y and A shadow mask positioning mechanism 28 that can be moved in the rotational direction as necessary, a microscope 29 for observing a light spot passing through a reference hole on a reference dot, and a shadow mask 18 are mounted on a mask fixing stud (not shown) of the face plate 17. (not shown).

After positioning the shadow mask so that the light spot passing through the reference hole of the shadow mask matches the reference dot using the microscope, the shadow mask is fixed to the mask fixing stud of the face plate.

According to this method, the reference dots are formed very clearly, and since the light rays incident on the reference dots do not pass through a correction lens or the like and each uses an independent light source that is easy to adjust, the positioning accuracy of the shadow mask is sufficient. ±0.005
It was possible to keep it within mm.

In addition, if necessary, the diameter of the light source for irradiating the reference hole of the shadow mask/face plate positioning device can be made smaller than the diameter of the light source for printing the reference dots on the face plate, thereby making it easier to assemble the shadow mask/face plate. This makes it easy to align the light spot that has passed through the reference hole of the mask with respect to the reference dot, thereby increasing precision.

In addition, the wavelength of the light source for the reference dot printing light source is selected from the area with the most efficient dot burning sensitivity, and the light source for irradiating the reference hole of the shadow mask/face plate assembly equipment is selected from a luminous or other light sensing element. It is possible to further improve the accuracy by selecting the most efficient region for the sensitivity of .

In the above example, a method was explained in which a light spot passing through a reference hole is visually compared to a reference dot in a shadow mask/face plate assembly device using a microscope. There is a method in which the position is determined by recognition of the button and this signal is fed back to the mask moving device to perform positioning, or the light source of the mask/face plate is a laser beam and multiple reference holes are made at one location as necessary (in this case, It is also possible to automate positioning by detecting interference fringes (referred to as reference holes in the present invention) and feeding back signals from the interference fringes to the shadow mask moving device.

Further, although the above description has been made regarding the production of phosphor screens, it goes without saying that the present invention can also be applied to the production of black stripe screens and other general mosaic screens.

Further, although a method of using an exposure process to produce a mosaic screen has been described, it goes without saying that a method of spraying a predetermined mosaic pattern may also be used.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view for explaining a color picture tube as a conventional cathode ray tube, Fig. 2 is a simplified cross-sectional view for explaining the pair exposure method, and Fig. 3 is a conventional master shadow mask method. FIG. 4 is a simplified sectional view illustrating the method of aligning the face plate exposed as shown in FIG. 3 and the shadow mask for finished products;
The figure is an explanatory partially cutaway perspective view of an example of a cathode ray tube completed by the manufacturing method of the present invention, and FIG. 6 shows phosphor dots and FIG. 1 is a simplified sectional view illustrating a method of exposing reference dots. FIG. 1 is a simplified sectional view illustrating a method of aligning a face plate formed by the exposure method of FIG. 6 and a shadow mask for a product. 7.18・・・Shadow mask for finished product, 4,26
...Reference dot, 10, 21 ... Phosphor dot exposure light source, 25 ... Reference dot exposure light source, 12゜23 ... Master shadow mask,
27...Reference dot alignment light source, 14, 29
······microscope.

Claims (1)

[Claims] 1. A screen comprising a group of phosphor dots having a mosaic pattern formed on the inner surface of the face plate, and a shadow mask spaced apart from the screen at a predetermined distance to determine the position at which the electron beam reaches the screen. A method for manufacturing a cathode ray tube includes the step of installing the face plate in an exposure device, and forming a group of phosphor dots having a mosaic pattern on the inner surface of the face plate using a master shadow mask installed in the exposure device. Also, a step of forming a reference dot on the inner surface of the face plate using a light source device corresponding to each of the reference holes through a plurality of reference holes provided in the master shadow mask, and a master shadow mask installed in the exposure device. A step of placing a product shadow mask having a plurality of reference holes at the same position on an assembly device having the same mechanical and optical arrangement as the exposure device, and forming a group of phosphor dots having the mosaic pattern. placing the face plater on the product shadow mask at a predetermined interval on the assembly device; and the step of placing the face plater on the product shadow mask at a predetermined interval, and the reference dots and reference holes of the product shadow mask printed on the face plate using the light source device of the assembly device. 1. A method for manufacturing a cathode ray tube, comprising the steps of: aligning the product shadow mask; and fixing the product shadow mask to the inner surface of the face plate. 2. Claim 1, characterized in that the diameter of the light source from the light source device of the assembly device with respect to the reference holes of the master shadow mask and the shadow mask for finished products is made smaller than the diameter of the light source from the light source device of the screen making device. A method for manufacturing cathode ray tubes. 3 Select the wavelength distribution of the light from the light source device of the assembly equipment to be in an efficient region for the visibility or the sensitivity of other light sensing elements, and also select the wavelength distribution of the light from the light source device of the exposure device to be efficient with respect to the reference dot. 2. The method of manufacturing a cathode ray tube according to claim 1, wherein the area is selected to have a good temperature. 4. In the assembly device, the position of the light spot that passes through the reference hole of the product shadow mask relative to the reference dot formed on the inner surface of the face plate and impinges on the reference dot formed on the inner surface of the face plate is sensed, and the position of the light spot is detected by this. A patent characterized in that the information provided by the product is processed by a computer, and the position of the product shadow mask is mechanically controlled by the output from the computer, so that the product shadow mask can be moved to an optimal position on the face plate. A method for manufacturing a cathode ray tube according to claim 1.