JPS5924485B2 - Method for manufacturing face plate for image pickup tube with built-in stripe filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a face plate for an image pickup tube with a built-in stripe filter.

Generally, an image pickup tube has a face plate having a structure in which one or more types of stripe filters 1 are adhered to a glass substrate 2, as shown in FIG.
The optical signal from the subject is sampled using the method, and an electrical signal corresponding to the color is obtained.

However, when operating an image pickup tube having a face plate having such a configuration, the following drawback occurs. That is, the surface of the stripe filter 1 is an uneven surface, and if a transparent conductive film or a photoelectric conversion film, such as a photoconductive film, is directly formed on this uneven surface, an abnormal electric field due to the uneven surface will cause an abnormal current when the image pickup tube is operated. There is a risk that this may be mistakenly recognized as a color signal. Therefore, in order to eliminate such defects, normally, as shown in FIG. The uneven surface is smoothed by bonding using an adhesive 4 having an equal value. Thereafter, the side 5 of the second glass substrate 3 that is not attached to the stripe filter 1 is polished to a predetermined thickness using the highly polished first glass substrate 2 as a reference. If the stripe filter pitch is about 50 to 60 pm, as described in the magazine "Television", Vol. 26, No. 2, 1972, page 105,
As described on page 08, it is necessary to reduce the distance between the stripe filter forming surface and the photoelectric conversion surface to several tens of μm in order to keep the blur of the image projected onto the photoelectric conversion surface of the stripe filter within a practical range. In order to obtain such a thickness, it is necessary to set the accuracy of the thickness of the first glass substrate 2 to a high accuracy of 3 to 5 μm in advance. On the other hand, the surface of the first glass substrate 2 may be scratched or damaged before the second glass substrate 3 is bonded, such as during the stripe filter manufacturing process.

When the second glass substrate 3 is bonded to the first glass substrate 2 that has been scratched in this way and a predetermined thickness is set, not only the second glass substrate 3 is polished; In order to remove scratches and the like, it is necessary to re-polish the first glass substrate 2, which has been set with high precision. However, re-polishing in this manner is impossible because the thickness will be distorted, and such a substrate 2 has no choice but to be discarded. Therefore, the glass substrate 2 whose thickness is set with high precision as described above.
The unit price is high, and the fact that it cannot be recycled in the manufacturing process of striped filters also increases the unit price of the finished product. Therefore, an object of the present invention is to improve the economic efficiency of the face plate itself by making it possible to use the first glass substrate 2 as a finished product even if it is scratched during the manufacturing process of the stripe filter 1. It is something to do.

In order to achieve such an object, the present invention has the gist of polishing the glass substrate 2 on which the stripe filter 1 is attached to set the thickness to a predetermined value, and will be described in detail below using examples. explain.

FIG. 3 is an explanatory diagram showing an embodiment of the method for manufacturing a face plate for an image pickup tube with a built-in stripe filter according to the present invention.
First, in the present invention, as shown in FIG. A Strife filter 31 is formed by a conventional method.

In the process of forming the stripe filter 31, the surface of the glass substrate 30, especially the surface on which the stripe filter 31 is not formed, is likely to be scratched due to repeated contact between the glass substrate 30 and the forming apparatus and handling of the substrate.
If it is installed in the image pickup tube with such scratches,
The shadows of scratches caused by light incident on the photoelectric conversion layer made of a transparent conductive film and, for example, a photoconductive film, are formed on the imaging surface, resulting in defects on the image playback screen. 4, or the glass substrate 30 must be discarded, which is a big disadvantage in terms of production. According to the present invention, it is sufficient that the thickness accuracy of the first glass substrate 30 is about ±0.2 degrees. Next, the accuracy of the thickness is almost ±(
3-5) Prepare a transparent second glass substrate 32 polished to a high precision of μ, and then attach the first and second glass substrates 3
Using the adhesive 33 having a refractive index equal to 0.32, the second
A glass substrate 32 is bonded to the filter forming surface of the first glass substrate 30. Next, the first glass substrate 30 is polished using the highly precisely set second glass substrate 32 as a reference to form a surface on which a photoelectric conversion layer is to be formed. The distance between the surface on which the stripe filter is formed and the surface on which the photoelectric conversion layer is to be formed, that is, the thickness of the glass substrate 30, is determined according to the following conditions: Since the imaging light is generally not parallel light, the projected image will be blurred, so it is necessary to keep it thin until the blurring is within an acceptable range. Therefore, according to the method of manufacturing a face plate for an image pickup tube with a built-in stripe filter of the present invention, the thickness is set to a predetermined value by polishing the first glass substrate 30 on which the stripe filter 31 is formed. Even if the first glass substrate 30 is slightly scratched before the filter is manufactured, the scratches can be removed by polishing.

Therefore, the first glass substrate 30 can be effectively reused,
It becomes economical. Note that in this case, the second glass substrate 32
Needless to say, since the thickness is set in advance with high precision, there is no need for polishing. Further, according to the present invention, the following effects are achieved.

That is, it is better for the adhesive 33 to be thin in terms of optical properties, but if it is too thin, Newton rings will occur even if there is a small thickness, so it cannot be made very thin. The thickness of practical soil is 5 to 10 microns. For this reason, in the conventional face plate, the thickness of the glass substrate 3 is set to 40 μm.
In this case, the distance between the stripe filter 1 and the photoconductive film is 45 to 50 μ. Note that in this case, the thickness of the transparent conductive film is ignored as it is sufficiently thin. On the other hand, according to the present invention, if the thickness of the glass substrate 30 is 40 μm as described above, the distance between the stripe filter 31 and the photoconductive film can be set to 40 μm since there is no need to consider the thickness of the adhesive 33.
Therefore, assuming that the lens of the television camera is the same, the blurring of the image projected onto the photoconductive film by the stripe filter 31 will be less with the lens of the present invention.As explained above, According to the method of manufacturing a face plate for an image pickup tube with a built-in stripe filter according to the present invention,
Even if the glass substrate on which the stripe filter is formed is scratched, the glass substrate can be effectively reused, which improves economic efficiency. In addition, when the face plate obtained by the method of the present invention is used, the projected image on the photoconductive film can be easily reused. This has the effect of reducing blur.

[Brief explanation of drawings]

1 and 2 are simplified configuration diagrams showing an example of a conventional face plate for an image pickup tube with a built-in stripe filter, and FIG. 3 is a simplified configuration diagram showing an example of a method for manufacturing a face plate for an image pickup tube with a built-in stripe filter according to the present invention. It is a diagram. 2, 3, 30, 32...Glass substrate, 1, 31
...Stripe filter, 4,33...
·glue.

Claims (1)

[Claims] 1. In a method for manufacturing a face plate for an image pickup tube with a built-in stripe filter in which a stripe filter is sandwiched between two glass substrates, a first glass substrate on which a stripe filter is formed on the surface of one of the glass substrates, The second glass substrate is bonded with an adhesive, and the surface of the first glass substrate is thinned to such an extent that blurring of the projected image on the photoconductive film of the stripe filter due to incident light to the image pickup tube does not pose a practical problem. A method for manufacturing a face plate for an image pickup tube with a built-in stripe filter, which comprises polishing and forming a photoelectric conversion layer made of a transparent conductive film, a photoconductive film, etc. thereon.