JPS6236343B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image pickup tube, for example, a phase-separated single-color image pickup tube.

An image pickup tube according to the present invention will be explained with reference to the drawings. The illustrated example is a single-tube type image pickup tube using a phase separation method, for example, as shown in FIG. That is, a face plate 20 having an optical color filter 3 and a target 4 disposed thereon is sealed to the inner surface of a glass face plate. An electron gun 6 is disposed within the tube 1, and the electron beam emitted from the gun scans the target 4. 7 is a field mesh electrode disposed inside 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; 9 is a conductive layer for horizontal and vertical electrostatic deflection; A focusing coil, 10, is an alignment coil. Further, the face plate 20 is sealed to the tube body 1 by sealing the indium ring 12 attached to the inner peripheral surface of the ring electrode 11 to the front end surface of the tube body 1 or to the front end surface of the tube body 1 (not shown). The ring is sandwiched between the front end surface of the ring and the face plate 20, and then crushed and sealed. Target 4
is mainly a transparent conductive film, that is, a transparent electrode 13
and a photoconductive film 14 deposited thereon. As shown in FIG. 3, the transparent conductive film 13 has, for example, a group of parallel electrodes arranged in the center of a transparent thin plate, that is, a thin glass plate 15, extending in a direction substantially perpendicular to the scanning direction of the beam in the scanning area of the beam. The electron beam scanning area 131, which has an overall square shape, for example, a rectangular shape, and its parallel electrodes are connected to each other in the ineffective portion of the imaging surface so as to pass through the face plate 20, as shown by chain lines in FIG. Terminal pins 17a and 17 provided in
Terminal derivation area 13 where terminal derivation is performed by b
2 and a rectangular electron beam scanning area 131 that extends in an arc shape along the periphery of the thin plate 15 so as to surround the electron beam scanning area 131 that has a rectangular shape as a whole. Electrode portion 1 having an outer peripheral region 134 provided through a removed portion 133
3a and 13b.

On the other hand, the optical color filter 3 includes, for example, red, green, and blue parallel filter groups (not shown) arranged on the inner surface of the face plate 2 in a predetermined positional relationship 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, that is, the transparent conductive film 13 is formed, is attached to the face plate 2 on which the optical color filter 3 is formed with an adhesive 16.
is glued to the inner surface of the

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

The ring electrode 11 is the field mesh electrode 7
In this case, the supporting flange portion 7a of the mesh electrode 7 is embedded and supported within the indium ring 12, and is electrically connected to the ring electrode 11.

In creating the face plate 20, the optical color filter is made of an organic material that can be easily patterned with relatively high precision. It is not possible to apply transparent electrodes to the surface. 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, which are separate bodies, respectively, 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
Due to the optical characteristics of the face plate 20, it is necessary to make it as thin as about 20 μm, and it is extremely difficult to handle such a thin glass plate without damaging it and form the transparent electrode 13 on it. Therefore, 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 side of the glass plate that has the electrode 13. Temporarily join the reinforcing smooth plate by
After that, the glass plate was rough-polished and mirror-polished from the back side to a required thin thickness, and this polished side was adhered to the face plate 2 on which the optical color filter was formed, and the above-mentioned temporary bonding was performed. The method used is to remove the reinforcing smooth plate.

However, when such a method is used, micro-cracks occur in the periphery of the thin glass plate when the glass plate is polished to reduce its thickness after the reinforcing smooth plate has been temporarily bonded as described above. This may damage the fine pattern of the transparent electrode 13 during, for example, peeling off the smooth plate.
This causes damage to the electrode 13, breakage, etc. In addition, the airtightness of the thin glass plate 15 may be impaired due to the cracks in the periphery caused by the above-mentioned polishing of the glass plate, or due to 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.

A method of manufacturing a face plate for a color image pickup tube that can avoid these drawbacks and provide various other benefits will be described with reference to FIG. 4 and subsequent figures.

First, as shown in Figure 4, for example, if the diameter is 22.8
Glass plate 2 as a transparent plate with a thickness of 2.5 mm
Prepare 1. One main surface 21a of this glass plate 21
The surface 21a has excellent smoothness, and a transparent electrode having a pattern as explained in FIG. 3, for example, is formed on this surface 21a. To achieve this, first, a transparent conductive film 22, such as a film of SnO ₂ , In ₂ O ₃ , In ₂ O ₃ -SnO ₂ or the like, is coated on the surface 21a of the glass plate 21 by a well-known technique such as vapor deposition or sputtering. It adheres to the skin. For this deposition, as mentioned above, since there is no optical color filter with relatively low heat resistance, this vapor deposition or sputtering is performed at the high temperature necessary to make this deposition strong. be able to.

Then, a photoresist film such as positive type AZ1350 (trade name manufactured by Shippray Co., Ltd.) or OFPR (trade name manufactured by Tokyo Ohka Co., Ltd.) is coated on this transparent conductive film 22, and photographic technology, that is, exposure and development processing is performed. A photoresist film 23 having a pattern corresponding to the transparent electrode pattern is then deposited. The transparent conductive film 22 is etched using the photoresist film 23 as an etching mask, and as shown in FIG. A transparent electrode 13 is formed. Then, a photoresist film 2 is placed on this transparent electrode 13.
3 remains attached, and a smooth plate 24 is adhered thereon. The smooth plate 24 is made of a glass plate having a diameter of 23 mm, for example, and a thickness of 1.0 mm, which is the same as or larger than the diameter of the substrate 21. 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 Alecom). It is desirable that the adhesive 25 and the photoresist film 23 be selected from materials that are soluble in the same solvent. Therefore, as mentioned above, the adhesive 2
Crystal bond which is soluble in acetone can be used as the photoresist film 23, and AZ1350 which is also 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. i.e. for example 150℃
Heating is performed at a temperature of about 160 DEG C. under a vacuum of about 0.1 torr to bring the smooth plate 24 and the transparent plate 21 into close contact with each other by removing air bubbles between them. After that, the vacuum is broken to atmospheric pressure and cooled. In this way, the smooth plate 24 is joined with the transparent electrode 13 on the transparent plate 21 sandwiched therebetween. In this case, the thickness of the adhesive after drying can be selected to be about 2 to 3 μm.

Next, the transparent plate 21 is rough-polished and mirror-polished from the surface 21b opposite to the side to which the smooth plate 24 is joined to a thickness of, for example, 20 μm, forming the transparent thin plate 15 explained in FIG. do. 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 with a smooth plate 24 such as beeswax,
A brazing material whose melting point is lower than that of the adhesive 25 used for bonding to the transparent plate 21 is used.

Then, as shown in FIG. 7, the transparent plate 21 is polished using abrasive grains of #1500 such as alumina abrasive.
The transparent plate 21 is roughly polished to a required thickness that is thicker than the transparent thin plate 15 finally obtained by lapping from the 1b side, but sufficiently thinner than the initial thickness of the transparent plate 21. Thereafter, running water cleaning and ultrasonic cleaning are performed to remove abrasive grains.
Next, the beeswax is melted by heating, and the smooth plate 2 is
4 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. agent 25
There is no possibility that the smooth plate 24 and the transparent plate 21 will be tilted or misaligned due to melting or softening.

Next, the lapped surface of the transparent plate 21 is polished to a mirror finish to give the transparent thin plate 1 a desired thickness, for example, 20 μm.
5, but prior to this mirror polishing, as shown in FIG. The circumferential surface is obliquely polished into a conical or curved surface, such as a spherical surface, having an angle θ ₁ to reduce the diameter. This peripheral surface diagonal polishing can be done by grinding into a conical shape as shown in the example with a chamfer grinder using a #1200 or larger diamond wheel, or by grinding a part of a spherical surface by using a grindstone with a concave surface. form like this. 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 to be 30° to 60°.

Thereafter, as shown in FIG. 9, the surface of the smooth plate 24 is placed on a polishing smooth surface plate 28 using beeswax whose melting point is lower than that of the adhesive 25, as described above.
4a is adhered, and the lap surface at the end of the transparent plate 21 is mirror-polished using, for example, CeO ₂ abrasive.

Next, the beeswax is similarly melted by heating, and the smooth plate 24 is peeled off from the surface plate 28. In this way, as shown in FIG. 10, a transparent thin plate 15 having a required thin thickness is formed of the transparent plate 21.

On the other hand, as shown in FIG. 11, a transparent substrate, that is, a smooth inner surface 2a of the glass face plate 2 of the image pickup tube, is coated by a well-known method in the usual manner.
An optical color filter 3 having a desired pattern is deposited and placed.

As shown in FIG. 12, a joined body of a transparent thin plate 15 and a smooth plate 24 is bonded to the surface of the face plate 2 on the side where the filter 3 is formed, on the lap side surface of the thin plate 15. This bonding is performed by using an adhesive 25 and an adhesive 26 that is resistant to solvents for the photoresist film 23, such as a photocurable epoxy photosensitive resin.

Then, as shown in FIG. 13, the circumferential surface of this joined body, especially the circumferential surface of the transparent thin plate 15, is set at an angle θ ₂ such that the circumferential surface of the smooth plate 24 is included and the smooth plate 24 side has a smaller diameter. Polishing of the diagonal circumferential surface is performed in the same manner as described above to remove portions 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 θ ₂ is desirably selected to be 30° to 60°, particularly 30° to 45°. 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, and a photoresist film 2
3. For example, dissolve the adhesive 25 and the photoresist film 23 using a common solvent with AZ1350, such as acetone, remove the smooth plate 24, and remove the photoresist film 23 covering the transparent electrode 13.
remove.

After that, as shown in FIG.
A photoconductive film 14 is formed on the thin glass plate 15 including the top.
be coated with. The face plate 20 is obtained in this way, and it should be noted that the face plate 20 has an inclined surface 29 on the circumferential surface of the transparent thin plate 15.

When constructing an image pickup tube using the face plate 5 obtained in this way, as shown in FIG. 1 or a ring (not shown) sealed to the front end surface of the tube body 1.

In this way, the face plate 20 is attached to the indium ring 12.
When sealing to the tube body 1 by crushing the face plate 20
Due to the presence of the inclined surface 29 around the sealing side of the transparent thin plate 15, when the face plate 20 is pressed together to crush the indium when sealing the face plate 20 to the tube body 1. The pressure applied to the periphery is reduced to the inclined surface 29.
This makes it possible to avoid accidents such as damage to the peripheral edge of the thin plate 15. That is, when manufacturing the face plate 20 shown in FIG.
0 is performed, and 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 20. That is,
Since the peripheral surface of the thin plate 15 is perpendicular to the plate surface direction, the shoulder portion of the inner peripheral edge of the thin plate 15 is perpendicular to the cross section. Therefore, in this case, indium ring 1
When 2 is crushed, a large force is applied to this right-angled shoulder, which tends to cause damage to the right-angled shoulder, but in the present invention, since the slope is a gentle surface due to the presence of the slope 29, such a right-angled shoulder is Accidents can be effectively avoided.

Furthermore, in particular, by polishing the circumferential surface by diagonal polishing, the occurrence of scratches and other flaws caused by this polishing can be drastically reduced. That is, when the relationship between the angle θ and the occurrence of scratches in this oblique circumferential polishing was measured, the results shown in FIG. 16 were obtained. According to this, the angle θ is 60° or less, especially
It can be seen that when the angle is set to 45° or less, the occurrence of scratches is drastically reduced. This measurement measures scratches within 0.5mm in length.
For example, a scratch with a length of 1 mm was counted as two, a scratch with a length of 1.5 was counted as three, and so on. Note that this angle θ
If the angle is less than 30°, the edges of the thin plate 15 will become sharp, causing a problem of chipping. Here, the angle θ,
That is, the angles θ ₁ and θ ₂ mentioned above are set to 30° to 60°.
There is a reason why the angle is selected from 30° to 45°.

Further, the measurement results of the relationship between the grain size of the diamond wheel used for polishing the oblique peripheral 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

In this way, by effectively avoiding defects such as cracks that occur or remain in the thin glass plate 15 of the face plate 20, it is possible to avoid deterioration of the degree of vacuum in the image pickup tube and obtain a highly reliable image pickup tube. can.

Furthermore, as described above, when the smooth plate 24 is bonded to the photoresist film 23 on the transparent electrode 13, the electrode 13 is protected by the photoresist film 23. Therefore, for example, foreign matter mixed in the adhesive 25 or the transparent plate 2
This has the advantage of avoiding the possibility that the electrode 13 will be damaged by cracks or glass fragments during polishing, for example, when the smooth plate 24 is peeled off.

Furthermore, when the size of the smooth plate 24 is made equal to or larger than that of the transparent plate 21, there is an effect of avoiding the inclusion of crack fragments generated during polishing of the transparent plate 21 between the smooth plate 24 and the transparent electrode 13. .

In the example described above, in order to obtain the thin transparent plate 15 with a small thickness from the transparent plate 21 with a large thickness, diagonal peripheral surface polishing at an angle θ ₁ is performed after rough polishing, and then mirror polishing is performed. As shown in Fig. 18, diagonal peripheral surface polishing is performed for rough polishing, and then
As shown in the figure, rough polishing and mirror polishing can also be performed.

Furthermore, in the above-mentioned example, the transparent electrode, that is, the transparent conductive film 13 is patterned, for example, in a comb-like shape, but when the transparent electrode 13 is not patterned and is formed entirely, The invention can be applied, and 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.

According to the present invention, as described above, by forming the transparent conductive film of the target into a special pattern, it is possible to reduce the stray capacitance of the target and improve the linearity of electron beam scanning. . That is, as explained in FIG. 1, in an image pickup tube in which the deflection means is constituted by the electrostatic deflection conductive layer 9 provided in the tube body 1, the terminal lead-out of the field mesh electrode 7 is What is done from the terminal pin 23 disposed on the stem of the tube body 1 as in a normal image pickup tube is the space in which the conducting wire connecting the terminal pin 23 and the field mesh electrode 7 is surrounded by the conductive layer 8 for electrostatic deflection. The electrostatic deflection electric field may be disturbed by passing through the electrostatic field.
This is undesirable because electrical insulation with the conductive layer for electrostatic deflection becomes a problem.

Therefore, in this type of image pickup tube, the terminals from the field mesh electrode 7 are led out from the ring electrode 11 at the front of the tube body 1, as described above.

In an image pickup tube having such a configuration, for example, a voltage of +50V is applied to the target, a voltage of 300 to 400V is applied to the field mesh electrode 5, and a center voltage of 330V is applied to the electrostatic deflection conductive layer 8, which is horizontally applied. A voltage on which a vertical deflection voltage is superimposed is applied, but in the above-described configuration, the electric field due to the indium ring 12 to which the power supply voltage to the field mesh electrode 7 is applied is applied to the front part between the target 4 and the field mesh electrode 7. There is a risk that the periphery of the surrounding electric field will be bent and the electron beam heading towards the target will be curved and its linearity will be lost.

However, according to the configuration of the present invention, the electron beam scanning area 13 of the transparent conductive film 13 of the target 4 is
By providing the outer circumferential region 134 surrounding the indium ring 1, it is possible to prevent the electric field from entering due to the indium ring 12 described above, and it is possible to avoid the problem of inhibiting the linearity of the electron beam due to the penetration of the electric field.

However, the outer peripheral area 134 is scanned by the scanning area 131.
When installing over an area other than Target 4
This increases the parasitic capacitance, causing significant afterimages and lowering the S/N ratio. However, in the present invention, the outer circumferential area 134 is formed in an arc shape along the periphery of the face plate, and the scanning area 131 is rectangular.
Since a large half-moon-shaped cutout 133 is created between the
It was possible to effectively avoid the decrease in .

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of the configuration of the image pickup tube, Fig. 2 is a sectional view of its main parts, Fig. 3 is a plan view of its electrodes, and Fig. 4 is a schematic diagram of the configuration of the image pickup tube.
Figures 1 to 15 are schematic cross-sectional views of an example of the face plate in each process, and Figures 16 and 17 are the measurement results of the angle of oblique peripheral surface polishing, the roughness of the grindstone, and the number of scratches, respectively. 18 and 19 are schematic cross-sectional views of some manufacturing steps in other examples of the present invention. 1 is an image pickup tube tube body, 20 is a face plate for the image pickup tube, 2 is a transparent substrate, 3 is an optical color filter, 15 is a transparent thin plate,
4 is the target, 7 is the field mesh electrode,
13 is a transparent conductive film, 131 is its electron beam scanning area, 132 is a terminal lead-out area, and 134 is an outer peripheral area.

Claims (1)

[Claims] 1. An image pickup tube body in which an electron gun and its attached structure are accommodated, and a disk sealed to the front end surface of the tube body via an indium ring, and a transparent conductive film and a photoconductive film are arranged on the inner surface. In an image pickup tube comprising a shaped face plate and a field mesh electrode disposed opposite to the inner surface of the face plate, a supporting part of the field mesh electrode is embedded in the indium ring, and the supporting part of the field mesh electrode is embedded in the indium ring. A transparent conductive film, which mechanically supports the field mesh electrode and leads out a power supply terminal, and which is arranged on the inner surface of the disc-shaped face plate, has a terminal lead-out area for leading out electrical signals to the outside, and a transparent conductive film arranged on the inner surface of the disc-shaped face plate. a rectangular electron beam scanning area extending from each other;
It is characterized by having an outer circumferential area extending in an arc shape along the periphery of the face plate outside the scanning area and facing the scanning area with an approximately half-moon-shaped cutout interposed therebetween. An image pickup tube.