JP2003217445A - Deposition method, x-ray image tube manufacturing method, deposition device and x-ray image tube manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a X-ray image tube manufacturing device enabling the proper vapor deposition of a material to be deposited. <P>SOLUTION: A vacuum sealed chamber 11 is put in a vacuum pressure condition and a crucible heater 3 is electrified by a power supply device 11. Cesium iodide is evaporated, diffused into the vacuum sealed chamber 1 and deposited on an input substrate 9. The total weight of a heating crucible 4 is measured by a gravimeter 6 and a weight signal is input to a control device 14 for every ten seconds. When an actual evaporation amount is larger than the preset evaporation amount of the cesium iodide per unit time, a heating value for the crucible heater 3 is reduced to reduce the evaporation amount of the cesium iodide. When the actual evaporation amount is smaller, the heating value for the crucible heater 3 is increased to increase the evaporation amount of the cesium iodide. Thus, a constant evaporation amount of cesium iodide per unit time is achieved. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor deposition method, an X-ray image tube manufacturing method, a vapor deposition apparatus and an X-ray image tube manufacturing apparatus capable of controlling a vapor deposition amount.

[0002]

2. Description of the Related Art Generally, an X-ray image tube is provided with an input surface having a photoelectric surface of, for example, cesium iodide for converting X-rays into photoelectrons at one end of a vacuum vessel, and the photoelectrons into a visible image at the other end. An output surface for conversion is provided, and an electron lens composed of a plurality of focusing electrodes for increasing the brightness of the output surface is provided between the input surface and the output surface, and X-rays input to the input surface are output. It is projected as a visible image on the surface.

The quality of an image cannot be improved unless the film thickness of cesium iodide and the state of vapor-deposited crystals are improved. It is necessary to control the deposition rate and the deposition amount of cesium. For example,
It is conceivable that the weight of the input substrate is measured by a weighing machine during the vapor deposition process, and the heater is controlled to control the evaporation amount according to the weight measured by the weighing machine.

[0004]

However, according to such a method, not all of the evaporated cesium iodide is deposited on the input substrate, but the evaporated cesium iodide is instantly deposited on the input substrate. Therefore, even if the heater is controlled by measuring the weight of the input board, it does not always correspond to the evaporation amount of cesium iodide at that time. It is not possible to control the evaporation amount of cesium iodide.
For example, when the evaporation amount of cesium iodide is large, a large amount of cesium iodide is deposited in the center of the input substrate, and it is difficult for cesium iodide to be deposited in the surroundings. Even if the amount of cesium iodide is equal, cesium iodide is not uniformly vapor-deposited.

When the amount of cesium iodide remaining in the crucible decreases as the vapor deposition progresses, the heat capacity of the heater increases with respect to the amount of cesium iodide remaining, and the cesium iodide evaporates vigorously. As a result, the amount of evaporation per unit time greatly changes, and the crystal columns of cesium iodide become thick, which makes it impossible to maintain the optical performance of each other.

Therefore, the reproducibility of the cesium iodide film deposited on the input substrate cannot be maintained, and the uniformity of the cesium iodide film cannot be maintained. Therefore, the cesium iodide film cannot be properly deposited. There is.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an evaporation method, an X-ray image tube manufacturing method, an evaporation apparatus and an X-ray image tube manufacturing apparatus which can appropriately evaporate an evaporation material. To do.

[0008]

SUMMARY OF THE INVENTION The present invention evaporates a vapor deposition material to be vapor-deposited on an object to be vapor-deposited, measures the weight of the vaporized vapor deposition material, and sets a preset value based on the measured weight of the vapor deposition material. The evaporation amount of the evaporation material is controlled according to the evaporation amount of the evaporation material that exists.By measuring the weight of the evaporation material to be evaporated, it is possible to evaporate according to the amount of the evaporation material that remains, and the evaporation amount per unit time. By appropriately controlling the above, the deposition material to be deposited can be appropriately deposited on the object to be deposited.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An X-ray image tube manufacturing apparatus which is a vapor deposition apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a vacuum airtight chamber 1 having a hollow interior is provided, and the vacuum airtight chamber 1 is evacuated to the outside so that the air inside the vacuum airtight chamber 1 is exhausted to a vacuum pressure state. A pump 2 is provided.

Further, a cylindrical crucible heater 3 as an evaporation means is provided below the vacuum airtight chamber 1.
The crucible heating heater 3 can accommodate a heating crucible 4 which is heated by the crucible heating heater 3, and the cesium iodide (CsI) powder 5 is accommodated in the heating crucible 4. Further, a weight scale 6 using a piezoelectric element or the like as a measuring means is disposed below the vacuum airtight chamber 1, and the weight scale 6 is housed in the heating crucible 4 and the heating crucible 4. The weight of the cesium powder 5 is measured. Since the weight of the cesium iodide powder 5 is measured, it is preferable that the resolution is small, but if the resolution is too small, the apparatus becomes extremely large. Therefore, the resolution is preferably about 0.1 g.

Further, in the upper part of the vacuum airtight chamber 1,
A rotating mechanism 7 is provided, and a holder 8 is suspended from the rotating mechanism 7, and the holder 8 is rotated by the rotating mechanism 7 at a constant angular velocity. Then, an input substrate 9 of an X-ray image tube, which is an object to be vapor-deposited, is placed on the holder 8, and a surface of the input substrate 9 on which cesium iodide is vapor-deposited faces downward and faces the heating crucible 4.

Further, it has a power supply device 11, and this power supply device 11 is connected to a crucible heating heater 3 via a power meter 12, and the crucible heating heater 3 is supplied with electric power from the power supply device 11.
To heat.

Further, a control device 14 as a control means is provided, and the power signal of the power meter 12 and the weight signal from the weight meter 6 are inputted to the control device 14, and the rotation mechanism 7 is supplied from the control device 14. And the control signal of the power supply device 11 is output.

Next, the operation of the above embodiment will be described.

First, the controller 14 presets the evaporation amount of cesium iodide according to time.

On the other hand, the vacuum pump 2 evacuates the air in the vacuum airtight chamber 1 to a vacuum pressure state.

In this way, the inside of the vacuum airtight chamber 1 is set to a vacuum pressure state, and the power source device 11 moves the crucible heater 3
When the power is turned on, the temperature of the crucible heating heater 3 rises to heat the heating crucible 4. Due to the heating of the heating crucible 4, the temperature of the cesium iodide powder 5 contained in the heating crucible 4 rises, and the cesium iodide evaporates and diffuses inside the vacuum hermetic chamber 1.

As described above, when the cesium iodide is evaporated and diffused into the vacuum airtight chamber 1, a part of the diffused cesium iodide is deposited on the input substrate 9.

Further, in order to reduce the unevenness of vapor deposition of cesium iodide on the input substrate 9, the rotating mechanism 7 is operated and the holder 8 is rotated to rotate the input substrate 9 at a constant angular velocity.

On the other hand, the power meter 12 detects the power supplied from the power supply device 11 to the crucible heater 3.
The electric power detected in step 2 is input to the control device 14 as a power signal, and the control device 14 controls the electric power from the power supply device 11 so as to keep the value of the power meter 12 constant.

In this state, when the evaporation of the cesium iodide powder 5 progresses, the weight of the entire heating crucible 4 decreases. Therefore, the weight scale 6 measures the weight of the entire heating crucible 4 and outputs the weight signal for a predetermined time. For example, it is input to the control device 14 every 10 seconds.

Further, the controller 14 calculates the difference between the value of the last weight signal read last time and the value of the current weight signal, calculates the weight of cesium iodide evaporated in the last 10 seconds, and calculates the weight of 10 seconds. The change in the evaporation amount of cesium iodide is obtained for each.

In the control device 14, the amount of cesium iodide vaporized per unit time, which is set in advance,
When the evaporation amount of cesium iodide measured for the last 10 seconds is large, the output of the power supply device 11 is lowered so that the electric power value measured by the electric power meter 12 decreases, and the calorific value of the crucible heating heater 3 is reduced. To reduce the evaporation amount of cesium iodide. On the contrary, if the amount of cesium iodide vaporized for the last 10 seconds is less than the preset amount of cesium iodide vaporized per unit time, the power meter 12
The output of the power supply device 11 is increased so that the electric power value measured by
Increases evaporation of cesium iodide. By performing such control, as shown in FIG. 2, the evaporation amount of cesium iodide per unit time can be set to a preset value. In addition, when the reduction amount of cesium iodide by the weight scale 6 is not fed back, FIG.
As shown in, when the cesium iodide evaporates and the amount of the remaining cesium iodide decreases, the heat capacity of the crucible heating heater 3 increases with respect to the cesium iodide. The evaporation amount of cesium increases.

When the evaporation amount of cesium iodide per unit time is made constant as shown in FIG. 2, the evaporation amount of cesium iodide changes as shown in FIG. The optical independence of the crystal columns of cesium chloride can be improved to reduce the variation between the formation of crystal columns, and the thickness of the cesium iodide deposited on the input substrate 9 can also be reduced during the deposition time. .

The amount of vapor deposition requires a film pressure of about 400 μm in order to reliably absorb X-rays, but since the diameter of the input substrate 9 is different from about 100 mm to 500 mm, the weight varies depending on the diameter. Has a diameter of 240
In the case of the mm input board 9, it is about 240 g.

However, even if the amount of cesium iodide deposited per unit time is kept constant, the tendency that the tips of the cesium iodide columnar crystals become thicker does not change, but the progress of vapor deposition is improved. The amount of cesium iodide evaporated per unit time should be reduced accordingly.

Specifically, as the evaporation of the cesium iodide powder 5 progresses, the total weight of the heating crucible 4 decreases, so that the weight of the heating crucible 4 at the start of vapor deposition and
By calculating the current difference in weight of the heating crucible 4, the total weight of the cesium iodide powder 5 evaporated from the start of vapor deposition can be calculated.

Therefore, as shown in FIG. 4, the controller controls so that the change in the evaporation amount of cesium iodide per unit time is inversely proportional to the total evaporation amount of the cesium iodide powder 5.
By setting the set value of 14 in advance, it is possible to prevent the tip of the cesium iodide columnar crystal from becoming thick.

As described above, by arbitrarily controlling the evaporation amount of cesium iodide per unit time as shown in FIG. 2 or FIG. 4, the vapor deposition film of cesium iodide on the input surface of the X-ray image tube can be formed. An X-ray image tube with improved quality and high image quality can be manufactured.

In the case of a thin film, it may not be so effective in terms of the resolution of the weighing scale 6 and the like, but the film thickness is 1
It is effective in the case of a thick film of μm or more.

[0032]

According to the present invention, by measuring the weight of the vapor deposition substance to be vaporized, it is possible to perform vaporization corresponding to the amount of the vaporized substance remaining, and it is possible to appropriately control the vaporization amount per unit time. The deposition material to be deposited can be appropriately deposited on the deposition target.

[Brief description of drawings]

FIG. 1 is a block diagram showing an X-ray image tube manufacturing apparatus according to an embodiment of the present invention.

FIG. 2 is a graph showing a case where the evaporation amount of cesium iodide per unit time is made constant.

FIG. 3 is a graph showing a case where the evaporation amount of cesium iodide per unit time increases in the comparative example.

FIG. 4 is a graph showing a case where the evaporation amount of cesium iodide per unit time is gradually reduced.

[Explanation of symbols]

3 Crucible heater as evaporation means 6 Weighing scale as measuring means 9 Input substrate as an object to be evaporated 14 Control device as control means

Continued front page    (72) Inventor Koji Masuda             8 East Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa             Shiba Electronics Engineering Co., Ltd. (72) Inventor Atsuya Yoshida             1385 Higashiyama, Shimoishi, Otawara, Tochigi Prefecture             Toshiba Nasu Electronic Tube Factory (72) Inventor Yoshinobu Sekijima             8 East Shinsugita-cho, Isogo-ku, Yokohama-shi, Kanagawa             Shiba Electronics Engineering Co., Ltd. F-term (reference) 4K029 BA41 BC07 CA01 DB05 DB18                       EA02                 5C027 EE01 EE04

Claims (4)

[Claims] 1. An evaporation material to be evaporated on an object to be evaporated is evaporated, the weight of the evaporated evaporation material is measured, and evaporation is performed according to a preset evaporation amount of the evaporation material based on the measured weight of the evaporation material. A vapor deposition method characterized by controlling the evaporation amount of a substance. 2. Evaporating the cesium iodide to be deposited on the substrate of the input surface of the X-ray image tube, measuring the weight of the cesium iodide, and presetting based on the measured weight of the cesium iodide. An X-ray image tube manufacturing method, characterized in that the evaporation amount of a vapor deposition material is controlled according to the evaporation amount of cesium iodide. 3. An evaporation means for evaporating an evaporation material to be deposited on an object to be evaporated, a measuring means for measuring the weight of the evaporation material, and a preset value based on the weight of the evaporation material measured by the measuring means. And a control unit for controlling the evaporation amount of the evaporation material by controlling the evaporation unit according to the evaporation amount of the evaporation material. 4. An evaporation means for evaporating cesium iodide to be deposited on the substrate on the input surface of the X-ray image tube, a measuring means for measuring the weight of the evaporated cesium iodide, and a measuring means for measuring the measured cesium iodide. An apparatus for producing an X-ray image tube, comprising: a control means for controlling the evaporation amount of a vapor deposition material by controlling the evaporation means according to a preset evaporation amount of cesium iodide based on the weight.