Double-indium-sealed image tube and manufacturing method thereof

Abstract

The invention discloses a double-indium-sealed image tube which comprises a tube shell, a photoelectric cathode assembled with a first end of the tube shell and a fluorescent screen assembly assembled with a second end opposite to the tube shell. A first indium sealing layer for fixing the first end and the photoelectric cathode together is arranged between the first end of the tube shell and the photoelectric cathode, and a second indium sealing layer for fixing the second end and the fluorescent screen assembly together is arranged between the second end of the tube shell and the fluorescent screen assembly. According to the double-indium-sealed image tube, pollution to the tube shell and the surface of the fluorescent screen is effectively reduced. In addition, the invention also discloses a manufacturing method of the double-indium-sealed image tube.

Description

Technical Field

[0001] This invention relates to the technical field of image tube manufacturing, and more particularly to a double indium sealed image tube and its manufacturing method. Background Technology

[0002] An image tube, also known as an image intensifier, is a vacuum optoelectronic device that uses the photoelectric effect to convert weak light signals into visible light images. It is a type of low-light detector.

[0003] The image tube consists of a shell, a photocathode, and a fluorescent screen, with the shell located between the photocathode and the fluorescent screen. To ensure the image tube's airtightness, sealed connections are required between the shell and the photocathode, and between the shell and the fluorescent screen.

[0004] For example, in the manufacturing process of an indium-sealed phosphor screen and a picture tube using the phosphor screen disclosed in Chinese Patent Application No. 200610022073.6, since the indium-sealed phosphor screen is first welded and sealed to the tube shell, and then the tube shell is sealed to the photocathode through photocathode indium sealing, the surface of the tube shell and the phosphor screen are contaminated during the welding and sealing process between the indium-sealed phosphor screen and the tube shell, thereby affecting the quality of the picture tube.

[0005] Therefore, there is an urgent need for a double indium-sealed image tube and its manufacturing method to reduce contamination on the tube shell and phosphor screen surface and overcome the above-mentioned defects. Summary of the Invention

[0006] One object of the present invention is to provide a dual indium-sealed image tube that reduces surface contamination of the tube casing and the phosphor screen. Another object of the present invention is to provide a method for manufacturing a dual indium-sealed image tube that reduces surface contamination of the tube casing and the phosphor screen.

[0007] To achieve the above objectives, the dual indium-sealed image tube of the present invention includes a tube shell, a photocathode assembled to a first end of the tube shell, and a phosphor screen assembly assembled to a second end opposite to the tube shell. A first indium sealing layer is provided between the first end of the tube shell and the photocathode to fix the first end and the photocathode together, and a second indium sealing layer is provided between the second end of the tube shell and the phosphor screen assembly to fix the second end and the phosphor screen assembly together.

[0008] Compared with the prior art, since a first indium sealing layer is provided between the first end of the tube shell and the photocathode to fix the first end and the photocathode together, and a second indium sealing layer is provided between the second end of the tube shell and the fluorescent screen assembly to fix the second end and the fluorescent screen assembly together, this design can perform indium sealing between the first end of the tube shell and the photocathode and between the second end of the tube shell and the fluorescent screen assembly in a vacuum environment (e.g., in a vacuum chamber), effectively preventing contaminants from entering the closed space defined by the photocathode, the tube shell and the fluorescent screen assembly, thereby reducing contamination on the surface of the tube shell and the fluorescent screen.

[0009] Preferably, the fluorescent screen assembly includes a fluorescent screen and a metal ring fitted over the fluorescent screen. The inner side of the metal ring is sealed to the fluorescent screen, and the outer side of the metal ring extends outward to form an outwardly protruding ring that is stacked with the end face of the second end of the housing. The second indium sealing layer is located between the outwardly protruding ring and the end face of the second end of the housing.

[0010] Preferably, the fluorescent screen assembly further includes a glass sealing ring for sealingly connecting the inner side of the metal ring to the fluorescent screen.

[0011] Preferably, the glass sealing ring is made of aluminosilicate glass and boron oxide, the metal ring is made of Kovar alloy, and the fluorescent screen is made of fiber optic glass.

[0012] Preferably, the metal ring has a first ring segment extending in the stacking direction of the outer convex ring and a second ring segment extending in the extending direction of the outer convex ring at a position away from the outer convex ring and extending into the tube shell. The second ring segment is arranged closer to the center line of the metal ring, and the first ring segment is arranged away from the center line of the metal ring. The first ring segment is also arranged side by side with the sidewall of the second end of the tube shell. The fluorescent screen extends partially out of the second ring segment in a direction away from the outer convex ring. The inner side of the metal ring is located on the second ring segment. The glass sealing ring is connected to both the second ring segment and the fluorescent screen.

[0013] Preferably, the metal ring further comprises a third ring segment and a fourth ring segment at a position away from the outer convex ring and extending into the tube shell. The third ring segment and the fourth ring segment are arranged sequentially towards the center line of the metal ring. The third ring segment extends along the extension direction of the outer convex ring and is connected to the first ring segment. The fourth ring segment extends along the stacking direction of the outer convex ring and is connected between the second ring segment and the third ring segment.

[0014] Preferably, the convex ring is perpendicularly connected to the first ring segment, and the convex ring, the first ring segment, the second ring segment, the third ring segment, and the fourth ring segment together form an integral structure.

[0015] To achieve the above objectives, the manufacturing method of the double indium-sealed image tube of the present invention is as follows: In a vacuum environment, an indium layer is melted on the sealing surface of the first end of the tube shell and an indium layer is melted on the sealing surface of the phosphor screen assembly; in a vacuum environment, a photocathode is assembled at the first end of the tube shell and a phosphor screen assembly is assembled at the second end of the tube shell to obtain an image tube to be sealed; in a vacuum environment, the image tube to be sealed is pressure-sealed, so that the indium layer on the sealing surface of the tube shell forms a first indium sealing layer that fixes the first end of the tube shell and the photocathode together, while the indium layer on the sealing surface of the phosphor screen assembly forms a second indium sealing layer that fixes the second end of the tube shell and the phosphor screen assembly together.

[0016] Preferably, in the manufacturing process of the fluorescent screen assembly, the metal ring, the glass sealing ring and the fluorescent screen are first placed into the fixture of the oven in sequence. Then, the oven temperature is heated to a preset temperature and held for a preset time. Then, the temperature is cooled to room temperature with the oven to obtain a fluorescent screen assembly in which the metal ring and the fluorescent screen are sealed together by the glass sealing ring.

[0017] Preferably, a nickel layer is plated on the sealing surface of the fluorescent screen assembly before melting an indium layer thereon.

[0018] Preferably, a nickel layer is plated on the sealing surface of the tube shell before melting an indium layer thereon. Attached Figure Description

[0019] Figure 1 This is an internal view of the double indium-sealed image tube of the present invention after being cut by a plane passing through its center line.

[0020] Figure 2 yes Figure 1 Enlarged view of section B.

[0021] Figure 3 yes Figure 1 The diagram shows the interior of the casing in a double indium-sealed image tube.

[0022] Figure 4 yes Figure 1 The diagram shows the internal structure of the phosphor screen assembly in a dual indium-sealed image tube.

[0023] Figure 5 It is a diagram showing the state of an indium layer melting on the sealing surface of the tube shell inside the vacuum chamber.

[0024] Figure 6 This is a diagram showing the state of an indium layer melting on the sealing surface of a display screen assembly within a vacuum chamber.

[0025] Figure 7 The diagram shows the state of the image tube to be sealed under pressure within the vacuum chamber.

[0026] Figure 8 It is by Figure 7 The diagram shows the internal structure of the double indium-sealed image tube obtained after pressure sealing of the image tube to be sealed. Detailed Implementation

[0027] To illustrate the technical content and structural features of the present invention in detail, the following description is provided in conjunction with the embodiments and accompanying drawings.

[0028] Please see Figure 1 The dual indium-sealed image tube 100 of the present invention includes a tube shell 10 and a first end 10a of the tube shell 10 (see...). Figure 1 , Figure 7 and Figure 8 The photocathode 20 is assembled at the upper end of the tube (see upper end) and the second end 10b opposite to the tube shell 10 (see upper end). Figure 1 , Figure 7 and Figure 8 The lower end of the housing 10 is equipped with a fluorescent screen assembly 30. A first indium sealing layer 40 is provided between the first end 10a of the housing 10 and the photocathode 20, fixing the first end 10a of the housing 10 and the photocathode 20 together, achieving a fixed seal between them. A second indium sealing layer 50 is provided between the second end 10b of the housing 10 and the fluorescent screen assembly 30, fixing the second end 10b of the housing 10 and the fluorescent screen assembly 30 together, achieving a fixed seal between them.

[0029] Since the first indium sealing layer 40 between the first end 10a of the housing 10 and the photocathode 20 and the second indium sealing layer 50 between the second end 10b of the housing 10 and the phosphor screen assembly 30 are in a vacuum environment (for example, see...), Figure 7 In the vacuum chamber referred to by reference numeral 200, indium sealing is performed once between the first end 10a of the tube shell 10 and the photocathode 20, and between the second end 10b of the tube shell 10 and the phosphor screen assembly 300. That is, in a single indium sealing process, a first indium sealing layer 40 is formed between the first end 10a of the tube shell 10 and the photocathode 20, and a second indium sealing layer 50 is formed between the second end 10b of the tube shell 10 and the phosphor screen assembly 30. Therefore, the efficiency is higher and the contamination prevention effect is better. Thus, under the action of the first indium sealing layer 40 and the second indium sealing layer 50, the quality of the double indium sealed image tube 100 of the present invention is ensured. More specifically, see the description below.

[0030] Combination Figure 1 , Figure 2 and Figure 4As an example, the fluorescent screen assembly 30 includes a fluorescent screen 31 and a metal ring 32 fitted over the fluorescent screen 31. The inner side 321 of the metal ring 32 is sealed to the fluorescent screen 31, and the outer side 322 of the metal ring 32 extends outward to form a protruding ring 323. The protruding ring 323 is stacked with the end face 11 of the second end 10b of the housing 10. At this time, the second indium sealing layer 50 is located between the end face 11 of the second end 10b of the housing 10 and the protruding ring 323. Therefore, the reliability of the indium sealing connection between the fluorescent screen assembly 30 and the second end 10b of the housing 10 is improved more effectively by means of the metal ring 32, and the sealing connection between the fluorescent screen 31 and the metal ring 32 is facilitated. See the description below for details.

[0031] At Figure 1 , Figure 2 and Figure 4 As an example, the phosphor assembly 30 also includes a glass sealing ring 33, which is used to seal the inner side 321 of the metal ring 32 to the phosphor 31. Alternatively, as an example, the glass sealing ring 33 is made of aluminosilicate glass and boron oxide, the metal ring 32 is made of Kovar alloy, and the phosphor 31 is made of fiber optic glass. This design makes the coefficient of thermal expansion of the glass sealing ring 33 between that of the metal ring 32 and the phosphor 31, which more effectively prevents thermal stress from causing cracks during cooling, thereby ensuring the quality of the phosphor assembly 30.

[0032] At Figure 1 , Figure 2 and Figure 4 As an example, the metal ring 32, located at position 32a away from the outer convex ring 323 and extending into the tube shell 10, has a first ring segment 32a1 extending in the stacking direction of the outer convex ring 323 (see the direction indicated by arrow A) and a second ring segment 32a2 extending in the extension direction of the outer convex ring 323 (i.e., the direction of the metal ring 32 from the inner side 321 to the outer side 322). The second ring segment 32a2 is arranged closer to the center line 324 of the metal ring 32, while the first ring segment 32a1 is arranged away from the center line 324 of the metal ring 32. The first ring segment 32a1 is also arranged side by side with the sidewall 12 of the second end 10b of the tube shell 10. This arrangement makes the sidewall 12 of the second end 10b of the tube shell 10 more compact with the first ring segment 32a1 of the metal ring 32, and also provides a larger clearance space for the fluorescent screen 31, thus allowing the fluorescent screen 31 to be made larger using this clearance space. The fluorescent screen 31 extends partially from the second ring segment 32a2 in a direction away from the outer convex ring 323 (also the direction indicated by arrow A). At this time, the inner side 321 of the metal ring 32 is located on the second ring segment 32a2, and the glass sealing ring 33 connects both the second ring segment 32a2 and the fluorescent screen 31, as shown in the diagram. Figure 2As shown; therefore, with the help of the second ring segment 32a2, the glass sealing ring 33 is positioned before sealing the metal ring 32 with the fluorescent screen 31, thereby improving the reliability and convenience of sealing the metal ring 32 with the fluorescent screen 31 by the glass sealing ring 33. Specifically, in Figure 1 , Figure 2 and Figure 4 In one example, at a position 32a of the metal ring 32 away from the outer convex ring 323 and extending into the tube shell 10, there are a third ring segment 32a3 and a fourth ring segment 32a4. The third ring segment 32a3 and the fourth ring segment 32a4 are arranged sequentially towards the center line 324 of the metal ring 32. The third ring segment 32a3 extends along the extension direction of the outer convex ring 323 (i.e., the direction of the metal ring 32 from the inner side 321 to the outer side 322), and the third ring segment 32a3 is connected to the first ring segment 32a1. The fourth ring segment 32a4 extends along the stacking direction of the outer convex ring 323, and the fourth ring segment 32a4 is connected between the second ring segment 32a2 and the third ring segment 32a3. Alternatively, in Figure 2 In this example, the convex ring 323, the first ring segment 32a1, the second ring segment 32a2, the third ring segment 32a3, and the fourth ring segment 32a4 together form an integrated structure. This design allows the metal ring 32 to be manufactured through multiple bending processes, thus simplifying the manufacturing process of the metal ring 32. In addition, it can provide more space for the fluorescent screen 31, thus allowing the fluorescent screen 31 to be made larger with the help of this space.

[0033] Among them, Yu Figure 2 In the example, the outer convex ring 323 is perpendicularly connected to the first ring segment 32a1, the third ring segment 32a3 is perpendicular to both the first ring segment 32a1 and the fourth ring segment 32a4, and the second ring segment 32a2 is perpendicular to the fourth ring segment 32a4. This further improves the ease of processing the metal ring 32. In addition, the junctions between the outer convex ring 323 and the first ring segment 32a1, the third ring segment 34a3 and the first ring segment 34a1, the third ring segment 34a3 and the fourth ring segment 34a4, and the fourth ring segment 34a4 and the first ring segment 34a1 are all arc-shaped transitions to prevent stress concentration defects in the metal ring 32 during bending and forming.

[0034] In summary, the manufacturing method of the dual indium-sealed image tube of the present invention is as follows: In a vacuum environment, for example, at... Figure 5 Inside the vacuum chamber 200 referred to by reference numeral 200, an indium layer 14 is melted on the sealing surface 13 of the first end 10a of the shell 10. Figure 6 Within the vacuum chamber 200 referred to by reference numeral 200, an indium layer 34 is melted on the sealing surface 3231 of the fluorescent screen assembly 30; in a vacuum environment, for example, in Figure 7Within the vacuum chamber 200 indicated by reference numeral 200, a photocathode 20 is assembled at the first end 10a of the tube shell 10, and a fluorescent screen assembly 30 is assembled at the second end 10b of the tube shell 10 to obtain the image tube 100a to be sealed; Figure 7 Inside the vacuum chamber 200 indicated by reference numeral 200, pressure sealing is performed on the image tube 100a to be sealed in the direction indicated by arrow F. This causes the indium layer 14 on the sealing surface 13 of the tube shell 10 to form a first indium sealing layer 40 that fixes the first end 10a of the tube shell 10 and the photocathode 20 together. Simultaneously, the indium layer 34 on the sealing surface 3231 of the fluorescent screen assembly 30 forms a second indium sealing layer 50 that fixes the second end 10 of the tube shell 10 and the fluorescent screen assembly 30 together. See the attached diagram for details. Figure 8 As shown, in a vacuum environment (vacuum chamber 200), by applying pressure to the image tube 100a to be sealed, the indium layer 14 on the sealing surface 13 of the tube shell 10 can form a first indium sealing layer 40, and the indium layer 34 on the sealing surface 3231 of the phosphor screen assembly 30 can form a second indium sealing layer 50. Furthermore, the manufacturing method of the double indium-sealed image tube of the present invention is described in more detail below.

[0035] Before melting an indium layer 14 on the sealing surface 13 of the housing 10, a nickel layer is first plated on the sealing surface 13; before melting an indium layer 34 on the sealing surface 3231 of the fluorescent screen assembly 30, a nickel layer is first plated on the sealing surface 3231; thus, with the help of the nickel layer, the nickel surface and the molten indium have good wettability, so that the molten indium can be easily spread on the nickel surface to form a uniform and dense film, thereby ensuring the formation of a complete and flawless indium layer 14 (34). Furthermore, during the manufacturing process of the fluorescent screen assembly 30, the metal ring 32, the glass sealing ring 33, and the fluorescent screen 31 are first placed sequentially into the fixture of an oven; then, the oven temperature is heated (e.g., gradually heated) to a preset temperature (e.g., 500 degrees Celsius, obviously, it could also be 460 degrees Celsius, 480 degrees Celsius, 520 degrees Celsius, or 540 degrees Celsius) and held at that temperature for a preset time (e.g., 1 hour, obviously, it could also be 0.6 hours, 0.8 hours, 1.2 hours, or 1.4 hours); then, the oven is cooled to room temperature, resulting in the fluorescent screen assembly 30 in which the metal ring 32 and the fluorescent screen 31 are sealed together by the glass sealing ring 33; thereby improving the reliability of the sealed connection between the metal ring 32 and the fluorescent screen 31 by the glass sealing ring 33.

[0036] Compared with the prior art, since a first indium sealing layer 40 is provided between the first end 10a of the tube shell 10 and the photocathode 20 to fix the first end 10a and the photocathode 20 together, and a second indium sealing layer 50 is provided between the second end 10b of the tube shell 10 and the fluorescent screen assembly 30 to fix the second end 10b and the fluorescent screen assembly 30 together, this design can perform indium sealing between the first end 10a of the tube shell 10 and the photocathode 20 and between the second end 10b of the tube shell 10 and the fluorescent screen assembly 30 in a vacuum environment (e.g., in a vacuum chamber 200) at one time, effectively preventing contaminants from entering the closed space 16 defined by the photocathode 20, the tube shell 10 and the fluorescent screen assembly 30, thereby reducing surface contamination of the tube shell 10 and the fluorescent screen 31.

[0037] It should be noted that, at Figure 2 In the case where the phosphor screen assembly 30 includes a phosphor screen 31, a metal ring 32, and a glass sealing ring 33, the sealing surface 3231 of the phosphor screen assembly 30 is formed by the surface of the protruding ring 323 outside the metal ring 32, and this surface faces the end face 11 of the second end 10b of the housing 10. Furthermore, indium sealing is a technology that utilizes the low-temperature melting characteristics of indium to achieve vacuum device or semiconductor packaging. Its core is to form an airtight seal by heating indium to melt it.

[0038] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are within the scope of the present invention.

Claims

1. A dual indium-sealed image tube, comprising a tube shell, a photocathode assembled to a first end of the tube shell, and a phosphor screen assembly assembled to a second end opposite to the tube shell, characterized in that, A first indium sealing layer is provided between the first end of the tube shell and the photocathode to fix the first end and the photocathode together, and a second indium sealing layer is provided between the second end of the tube shell and the fluorescent screen assembly to fix the second end and the fluorescent screen assembly together.

2. The dual indium-sealed image tube according to claim 1, characterized in that, The fluorescent screen assembly includes a fluorescent screen and a metal ring fitted over the fluorescent screen. The inner side of the metal ring is sealed to the fluorescent screen. The outer side of the metal ring extends outward to form an outwardly convex ring that is stacked with the end face of the second end of the housing. The second indium sealing layer is located between the outwardly convex ring and the end face of the second end of the housing.

3. The dual indium-sealed image tube according to claim 2, characterized in that, The fluorescent screen assembly also includes a glass sealing ring for sealingly connecting the inner side of the metal ring to the fluorescent screen.

4. The dual indium-sealed image tube according to claim 3, characterized in that, The glass sealing ring is made of aluminosilicate glass and boron oxide, the metal ring is made of Kovar alloy, and the fluorescent screen is made of fiber optic glass.

5. The dual indium-sealed image tube according to claim 3, characterized in that, The metal ring, located away from the outer convex ring and extending into the tube shell, has a first ring segment extending in the stacking direction of the outer convex ring and a second ring segment extending in the extending direction of the outer convex ring. The second ring segment is arranged closer to the center line of the metal ring, and the first ring segment is arranged away from the center line of the metal ring. The first ring segment is also arranged side by side with the sidewall of the second end of the tube shell. The fluorescent screen extends partially from the second ring segment in a direction away from the outer convex ring. The inner side of the metal ring is located on the second ring segment, and the glass sealing ring connects the second ring segment and the fluorescent screen.

6. The dual indium-sealed image tube according to claim 5, characterized in that, The metal ring has a third ring segment and a fourth ring segment at a position away from the outer convex ring and extending into the tube shell. The third ring segment and the fourth ring segment are arranged sequentially towards the center line of the metal ring. The third ring segment extends along the extension direction of the outer convex ring and is connected to the first ring segment. The fourth ring segment extends along the stacking direction of the outer convex ring and is connected between the second ring segment and the third ring segment.

7. The dual indium-sealed image tube according to claim 6, characterized in that, The convex ring is perpendicularly connected to the first ring segment, and the convex ring, the first ring segment, the second ring segment, the third ring segment, and the fourth ring segment together form an integral structure.

8. A method for manufacturing a double indium-sealed image tube, characterized in that, In a vacuum environment, an indium layer is melted on the sealing surface of the first end of the tube shell and an indium layer is melted on the sealing surface of the fluorescent screen assembly. In a vacuum environment, the photocathode is assembled at the first end of the tube shell and the fluorescent screen assembly is assembled at the second end of the tube shell to obtain the image tube to be sealed. In a vacuum environment, the image tube to be sealed is pressure sealed, so that the indium layer on the sealing surface of the tube shell forms a first indium sealing layer that fixes the first end of the tube shell and the photocathode together, and at the same time, the indium layer on the sealing surface of the fluorescent screen assembly forms a second indium sealing layer that fixes the second end of the tube shell and the fluorescent screen assembly together.

9. The method for manufacturing a double indium-sealed image tube according to claim 8, characterized in that, In the manufacturing process of the fluorescent screen assembly, the metal ring, the glass sealing ring and the fluorescent screen are first placed into the fixture of the oven in sequence. Then, the oven temperature is heated to the preset temperature and held for the preset time. Then, the temperature is cooled to room temperature with the oven to obtain the fluorescent screen assembly in which the metal ring and the fluorescent screen are sealed together by the glass sealing ring.

10. The method for manufacturing a double indium-sealed image tube according to claim 8, characterized in that, Before melting an indium layer on the sealing surface of the fluorescent screen assembly, a nickel layer is first plated on the sealing surface; before melting an indium layer on the sealing surface of the housing, a nickel layer is first plated on the sealing surface.

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