JPS6057175B2 - Manufacturing method for image pickup tube face plate - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a face plate for a color image pickup tube, for example, a phase separation type single image pickup tube system.

For example, a single-tube type image pickup tube using a phase separation method has a first
As shown in the figure, a drawing plate 5 is sealed at the front end of the tubular body 1, as shown in FIG. It consists of being worn.

An electron gun 6 is disposed within the tube 1, and an electron beam emitted from the gun scans the target 4. 7 is a mesh electrode placed in the tube 1 facing the target 4; 8 is a conductive layer for horizontal and vertical electrostatic deflection deposited on the inner peripheral surface of the tube 1; and 9 is a focusing coil. , 10 are alignment coils.

Further, the sealing of the drawing board 5 to the tube body 1 is performed using a ring electrode 11.
The indium ring 12 adhered to the inner peripheral surface of the tube body 1
or the front end surface of a ring (not shown) sealed to the front end surface of the tubular body 1 and the drawing board 5 and is sealed by being crushed. Target 4 is
It mainly comprises a transparent electrode 13 and a photoconductive film 14 deposited thereon. As shown in FIG. 3, the transparent electrode 13 is composed of a group of parallel electrodes arranged on a transparent thin plate, that is, a glass thin plate 15, extending in a direction substantially perpendicular to the scanning direction of the beam. are connected to each other in the ineffective portion of the imaging surface to form comb-shaped electrode portions 13a and 1.
3b. On the other hand, the optical color filter 3 includes, on the inner surface of the face plate 2, red, green, and blue parallel filter groups (not shown) are sequentially arranged in predetermined positional relationships with the parallel electrode groups of the transparent electrode 13. Consists of an organic filter.

The transparent thin plate 15 on which the transparent electrode 13 is formed is
An adhesive 16 is used to adhere the optical color filter 3 to the inner surface of the face plate 2 formed thereon.

A photoconductive surface, ie a photoelectric conversion surface 14, made of antimony trisulfide, for example, is deposited on the transparent electrode 13.

Terminals for the pair of electrode parts 13a and 13b of the transparent electrode 13 are led out by terminal pins 17a and 17b provided so as to penetrate the face plate 5, as shown by chain lines in FIG.

Further, the ring electrode 11 is, for example, a terminal of the mesh electrode 7, and in this case, the flange portion of the mesh electrode 7 is embedded in the indium ring 12 to be electrically connected to the ring electrode 11. obtain. As mentioned above, when producing a picture plate for a color image pickup tube, the optical color filter is usually made of an organic material that can be easily patterned with relatively high precision. Because of its low properties, transparent electrodes cannot be directly deposited on it. That is, the transparent electrode 13 is deposited by sputtering, vapor deposition, or the like while being heated to, for example, about 400° C., and this heat causes a change in the spectral characteristics of the color filter. Therefore, as described above, the optical color filter 3 and the transparent electrode 13 are formed in advance on the face plate 2 and the thin glass plate 15, respectively, which are separate bodies, and then the two are bonded together using the adhesive 16. A manufacturing method is used. However, when using such a method, the thin glass plate 15 needs to be as thin as 20 μm due to the optical characteristics of the drawing plate 5, and it is difficult to handle such a thin glass plate without damaging it. Since it is extremely difficult to form the transparent electrode 13 on
Normally, when forming the transparent electrode 13, the transparent electrode 13 is first formed on a relatively thick transparent plate, that is, a glass plate, and then an adhesive is applied to the surface of the glass plate on the side where the electrode 13 is provided. A reinforcing smooth plate is temporarily bonded, and then the glass plate is rough-polished and mirror-polished from the back side to a required thin thickness, and this polished side is used as a face plate 2 on which an optical color filter is formed. and temporarily joined as described above.
The method used is to remove the reinforcing smooth plate.

However, when such a method is used, as described above, after the reinforcing smooth plate is temporarily bonded, when the glass plate is polished to reduce its thickness, microcracks are generated in the peripheral area of the thin glass plate. However, this may damage the fine pattern of the transparent electrode 13 during, for example, peeling off the smooth plate, resulting in damage or disconnection of the electrode 13.

In addition, the airtightness of the thin glass plate 15 may be impaired due to cracks in the peripheral area caused by the above-mentioned polishing of the glass plate, scratches caused by glass fragments caused by the cracks, or due to the growth of cracks, resulting in poor imaging. This leads to a decrease in the vacuum level of the tube. The present invention avoids the above-mentioned drawbacks, and furthermore, as will become clear from the description of the embodiments of the manufacturing method of the present invention, a color that can provide various benefits that cannot be obtained by conventional manufacturing methods. image pickup tube)
There is also one that provides a method for manufacturing a face plate.

The manufacturing method of the present invention will be explained in detail with reference to FIG. 4 and subsequent figures.

First, as shown in FIG. 4, a glass plate 21 as a transparent plate having a diameter of, for example, 22.8 mm and a thickness of 2.5 mm is prepared.

One main surface 21a of this glass plate 21 is made to be a surface with excellent smoothness, and a transparent electrode having a pattern as described in FIG. 3, for example, is formed on this surface 21a. To do this, first, a transparent conductive film 2 is placed on the surface 21a of the glass plate 21.
2. For example, SrlO2, Irl2O3, In2O3-
A film such as SnO2 is deposited by well known techniques such as evaporation and sputtering. For this deposition, as mentioned above, since there is no optical color filter with relatively low heat resistance, this vapor deposition or puttering must be performed at a high temperature necessary to make this deposition strong. I can do it. Then, on this transparent conductive film 22, a photoresist film, for example, a positive type AZl35O (trade name manufactured by Shupley Co., Ltd.) is applied.
, or 0FPR (trade name, manufactured by Tokyo Ohka Co., Ltd.) is applied, and a photoresist film 23 having a pattern corresponding to the transparent electrode pattern is formed by applying a photographic technique, that is, exposure and development processing.

Using this photoresist film 23 as an etching mask, the transparent conductive film 22 is etched, as shown in FIG.
A transparent electrode 13 having a pattern corresponding to the pattern of the photoresist film 23, ie, the transparent electrode 13 having the pattern explained in FIG. 3, for example, is formed. Then, with the photoresist film 23 remaining on the transparent electrode 13, a smooth plate 24 is adhered thereon. The diameter of this smooth plate 24 is about the same as or larger than the diameter of the substrate 21, for example, 23w! It is composed of a glass plate with a thickness of 1.0 m. The smooth plate 24 is composed of glass plates whose opposing main surfaces 24a and 24b are mutually smooth and have excellent parallelism. The smooth plate 24 can be bonded to the transparent plate 21 using an adhesive 25 having a relatively high melting point and soluble in a solvent such as acetone, for example, a thermoplastic polymer crystal bond (trade name manufactured by Alemco). . This adhesive 25 and photoresist film 23
It is desirable that the material be selected from materials that are soluble in the same solvent. Therefore, as mentioned above, the adhesive 2
As 5, acetone-soluble crystal bond is used,
Similarly, AZl35O, which is soluble in acetone, can be used as the photoresist film 23. The transparent plate 21 and the smooth plate 24 are bonded together by, for example, vacuum heat treatment. That is, the smooth plate 24 and the transparent plate 21 are brought into close contact with each other by removing air bubbles between them by heating to about 150'C to 160'C and reducing the vacuum to about 0.1 torr. After that, the vacuum is broken to atmospheric pressure and cooled. In this way, the transparent electrode 13 on the transparent plate 21
A smooth plate 24 is joined between the two. In this case, the thickness of the adhesive after drying can be selected to be about 2 to 3 μm. Next, the surface 21b opposite to the side where the transparent plate 21 and the smooth plate 24 are joined is roughly polished and mirror polished to a thickness of, for example, 20 pm, and the transparent thin plate 15 explained in FIG. Configure.

Therefore, as shown in FIG. 6, first, the joined body of the transparent plate 21 and the smooth plate 24 is adhered to the smooth surface plate 27 for lapping and polishing on the outer surface 24a side of the smooth plate 24. This adhesion is performed between a smooth plate 24 such as beeswax and a transparent plate 21.
A brazing material whose melting point is lower than that of the adhesive 25 used for bonding is used. As shown in FIG. 7, the alumina abrasive is thicker than the transparent thin plate 15 finally obtained by lapping the transparent plate 21 from the surface 21b side using #1500 abrasive grains, but it is transparent. The plate 21 is roughly polished to a required thickness that is sufficiently thinner than the initial thickness.

Thereafter, running water cleaning and ultrasonic cleaning are performed to remove abrasive grains. Next, the beeswax is melted by heating, and the smooth plate 24 is
The joined body of the transparent plate 21 and the transparent plate 21 is peeled off from the smooth surface plate 27.
In this case, the adhesive 25 that joins the smooth plate 24 and the transparent plate 21 is an adhesive whose melting point is higher than that of the adhesive for the surface plate 27, so that when bonding to the surface plate 27 and peeling off, the adhesive 25 is used. The agent 25 is melted or softened, and the smooth plate 2
4 and the transparent plate 21 will not be tilted or misaligned. Next, the lapped surface of the transparent plate 21 is mirror-polished to form a transparent thin plate 15 having a required thickness, for example, 20 μm. The circumferential surface of the joined body, especially the circumferential surface of the transparent plate 21, is formed into a conical or curved surface having an angle 01 such that the wrap surface side of the transparent plate 21 has a smaller diameter, for example, a spherical circumferential surface obliquely. Perform polishing.

This circumferential surface diagonal polishing can be done by grinding into a conical surface as shown in the example shown in the figure with a chamfer grinder using a #1200 or larger diamond wheel, or by grinding a part of a spherical surface with a grindstone having a concave surface. to form. This oblique polishing of the peripheral surface is based on the discovery that cracks occurring in the peripheral portion during the next mirror polishing can be effectively avoided. The angle θ1 of this oblique polishing is selected from 30 to 60. After that, as shown in FIG. 9, the smooth surface plate 2 for polishing is
8, the surface 24a of the smooth plate 24 is bonded using beeswax whose melting point is lower than that of the adhesive 25, as described above, and the lapped surface at the end of the transparent plate 21 is bonded with, for example, CeO2 abrasive. Polish to a mirror finish.

Next, the beeswax is similarly melted by heating, and the smooth plate 24 is peeled off from the surface plate 28. In this way, the 10th
As shown in the figure, a transparent thin plate 15 having a required thin thickness is composed of a transparent plate 21. On the other hand, as shown in FIG. 11, an optical color filter 3 having a desired pattern is formed on a smooth inner surface 2a of a transparent substrate, that is, a glass face plate 2 of an image pickup tube, by a well-known method. Form the adhesion and leave it.

As shown in FIG.
A transparent thin plate 15 and a smooth plate 24 are placed on the side where
The joined body is joined on the lap side surface of the thin plate 15.

This bonding is performed using an adhesive 25 and an adhesive 26 that can withstand solvents for the photoresist film 23, such as a photocurable epoxy photosensitive resin. and,
As shown in FIG.
A diagonal peripheral surface polishing having an angle 02 similar to that described above is performed such that the diameter on the 4th side is reduced to remove a portion of the thin plate 15 where defects such as cracks have occurred at the peripheral portion.

This diagonal circumferential surface polishing is also performed to form a curved surface such as a conical surface or a spherical surface. In this case, the angle θ2 is desirably selected to be 30 to 60 degrees, particularly 30 to 45 degrees. Note that this diagonal polishing can be performed by holding the peripheral portion of the outer surface of the face plate 2 in a jig. Next, as shown in FIG. 14, an adhesive 25, for example, crystal bond, is applied.
The adhesive 25 and the photoresist film 23 are dissolved using a solvent common to the photoresist film 23, such as AZl35O, such as acetone, the smooth plate 24 is removed, and the photoresist film 23 covering the transparent electrode 13 is removed. Remove.

Thereafter, as shown in FIG. 15, a photoconductive film 14 is deposited on the thin glass plate 15, including the transparent electrode 13.

If this is followed, a face plate 20 for a color image pickup tube can be obtained. However, it should be noted that the picture plate 20 obtained by the manufacturing method of the present invention has an inclined surface 29 on the circumferential surface of the transparent thin plate 15. This is an important point. Then, the face plate 2 obtained in this way
0, as shown in FIG. 16, the face plate 20 is attached to the front end surface of the tube body 1 or
A ring (not shown) is sealed to the front end face of the holder.

In FIG. 16, parts corresponding to those in FIG. 2 are designated by the same reference numerals, and redundant explanation will be omitted. In this way, the face plate 20 is
When sealing to the tube body 1 by crushing the indium ring 12, the presence of the inclined surface 29 around the sealing side of the face plate 20 prevents the sealing of the face plate 20 to the tube body 1. When pressing both together to crush the indium,
The pressure applied to the periphery of the transparent thin plate 15 can be dispersed along the inclined surface 29, and accidents such as damage to the periphery of the thin plate 15 can be avoided.

That is, when manufacturing the conventional face plate 5, the peripheral surface of the face plate 5 is finally polished and removed in order to remove defects such as cracks that occur during polishing of the peripheral portion of the thin plate 15. In this case, the finished polished surface of the peripheral surface is formed into a cylindrical surface having the same diameter at each part along the axis of the face plate 5. That is, since the peripheral surface of the thin plate 15 is perpendicular to the direction of the plate surface, the shoulder portion of the inner peripheral edge of the thin plate 15 is perpendicular to the cross section. Therefore, in this case, when the indium ring 12 is crushed, a large bulge is given to this right-angled shoulder, which tends to cause damage to the right-angled shoulder, but in the present invention, the presence of the inclined surface 29 creates a gentle surface. Therefore, such accidents can be effectively avoided. Furthermore, especially when the circumferential surface is polished by diagonal polishing, the occurrence of scratches such as cracks accompanying this polishing can be drastically reduced.

That is, when the relationship between the angle 0 and the occurrence of scratches in this oblique peripheral surface polishing was measured, the results shown in FIG. 17 were obtained. According to this, it can be seen that when the angle θ is set to 60 or less, especially 45 or less, the occurrence of scratches is drastically reduced. This measurement is 0.5T in length! r! One flaw is within FL, and for example, the length is 1T! r! There are 2 scratches on n, 1.5
T! r! Number n scratches were counted as 3, and so on. If the number of angles 0 is less than 30, the edges of the thin plate 15 will become sharp, causing a problem of chipping. This is the reason why the angle 0, that is, the angles 01 and 02 mentioned above, are selected to be between 30 degrees and 60 degrees, especially between 30 degrees and 45 degrees. Furthermore, the measurement results of the relationship between the grain size # of the diamond wheel polished on the oblique circumferential surface and the number of similar scratches are shown in FIG. As is clear from this, the occurrence of scratches is drastically reduced with #600 and above. Furthermore, as explained in FIG. 10, when performing diagonal circumferential polishing in which the diameter is gradually increased in the direction in which the polishing progresses prior to mirror polishing, the occurrence of cracks during mirror polishing can be drastically reduced. It was also confirmed that

As described above, according to the configuration of the present invention, the face plate 20
Since defects such as cracks that occur or remain in the glass thin plate 15 can be effectively avoided, deterioration of the degree of vacuum in the image pickup tube can be avoided and a highly reliable image pickup tube can be obtained.

Further, as described above, in a state where the photoresist film 23 is coated on the transparent electrode 13, the smooth plate 24 is placed on top of the photoresist film 23.
When bonding, since the electrode 13 is protected by the photoresist film 23, for example, foreign matter mixed in the adhesive 25, cracks or glass fragments during polishing of the transparent plate 21, etc. When the smooth plate 24 is peeled off, the electrode 13
There is an advantage in avoiding the risk of being harmed.

Further, when the size of the smooth plate 24 is made equal to or larger than that of the transparent plate 21, it is possible to avoid the crack fragments generated during polishing of the transparent plate 21 from entering between the smooth plate 24 and the transparent electrode 13.

In the above example, in order to obtain the thin transparent plate 15 from the thick transparent plate 21, diagonal peripheral surface polishing at an angle of 01 was performed after rough polishing, and mirror polishing was then performed. As shown in FIG. 19, oblique peripheral surface polishing can be performed before rough polishing, and then, as shown in FIG. 20, rough polishing and mirror polishing can be performed. Furthermore, in the above-mentioned example, the transparent electrode 13 is patterned into a comb-like shape, but the present invention can be applied to a case where the transparent electrode 13 is not patterned and is formed over the entire surface. In this case, the step of depositing the photoresist film 23 and the step of etching the transparent conductive film explained in FIG. 4 are omitted.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the image pickup tube, Fig. 2 is a sectional view of the main parts of the image pickup tube with a face plate obtained by the conventional method, Fig. 3 is a plan view of the electrodes, and Figs. Fig. 15 is a linear cross-sectional view of each step of an example of the method of the present invention, Fig. 16 is a cross-sectional view of the main part of an image pickup tube using a face plate obtained by the manufacturing method of the present invention,
Fig. 17 and Fig. 18 are diagrams showing the measurement results of the angle of oblique circumferential polishing, the roughness of the grindstone, and the number of scratches, respectively, and Fig. 19 and Fig. 20 are diagrams showing the results of measuring the angle of oblique circumferential polishing, the roughness of the grindstone, and the number of scratches, respectively. It is a line sectional view of a part of the process. 1 is an image pickup tube body, 20 is a face plate for the image pickup tube, 2 is a transparent substrate,
3 is an optical filter, 15 is a transparent thin plate, 4 is a target,
13 is its transparent electrode, and 14 is a photoconductive film.

Claims (1)

[Claims] 1 A step of depositing a transparent conductive film on a transparent plate and depositing a resist film having a desired pattern on the transparent conductive film, and etching the transparent conductive film using the resist film as an etching resist to form the desired pattern. a step of forming a transparent electrode, a step of bonding a smooth plate on the transparent plate having the transparent electrode, and a step of polishing the transparent plate from the side opposite to the side having the transparent electrode to form a transparent thin plate. a step of bonding a transparent substrate with a filter to the transparent thin plate; a step of obliquely polishing the peripheral surface of the transparent thin plate together with the smooth plate;
A method for manufacturing a picture plate for an image pickup tube, comprising the steps of removing the resist film and the smooth plate, and forming a photoconductive film on the transparent electrode.