CN114975043A - Sub-light fluorescent screen for low-light image intensifier and preparation method thereof - Google Patents

Abstract

The invention discloses a matt fluorescent screen for a low-light-level image intensifier and a preparation method thereof. The preparation method comprises respectively preparing ultrathin glue solution, potassium silicate solution and organic film solution; and sequentially coating the ultrathin glue, the fluorescent powder, the organic film solution and the aluminum film on the optical fiber panel substrate. The fluorescent screen has the matte characteristic, and can greatly reduce the light emissivity, thereby reducing the light feedback of the fluorescent screen, improving the imaging contrast of the image intensifier, and enabling the imaging to be clearer and more striking and the color to be brighter and more beautiful. The method has the advantages of low production cost, high efficiency and the like.

Description

Sub-light fluorescent screen for low-light image intensifier and preparation method thereof

Technical Field

The invention relates to the field of low-light-level image intensifiers, in particular to a matte fluorescent screen for an image intensifier and a preparation method thereof.

Background

The fluorescent screen is an important component of the low-light level image intensifier, can convert an electronic image into a visible light image, and the performance of the fluorescent screen directly influences the image quality and the observation effect of the image output by the image intensifier. The imaging performance of the fluorescent screen has a close relationship with the fluorescent powder material and the screen manufacturing process, such as the size and the shape of fluorescent powder particles, the agglomeration condition, the thickness of a powder layer, the thickness of an aluminum film, the thickness of a substrate adhesive, the thickness of an organic film, the film forming mode thereof and the like, which all affect the imaging performance of the fluorescent screen. In the process of preparing the fluorescent screen, the structure of the fluorescent screen comprises a substrate glue layer, a fluorescent powder layer, an organic film layer and an aluminum film layer. After the preparation is finished, the substrate adhesive layer and the organic film layer are removed under the high-temperature condition, and finally, only the fluorescent powder layer and the aluminum film layer are left on the glass or optical fiber panel substrate. The aluminum film layer is used as the surface of the fluorescent screen, has certain light reflectivity, and can reflect a part of light input by the photocathode and light generated by the fluorescent screen to the photocathode so as to generate optical feedback. The optical feedback phenomenon can seriously reduce the contrast performance of the image intensifier, so that the imaging is not clear and the imaging picture is blurred. The conventional method for eliminating the optical feedback phenomenon is to increase the thickness of the aluminum film layer, but this method causes an increase in production cost and a decrease in production efficiency. Here, we propose a new method, through optimizing the process, in the manufacturing process of the fluorescent screen, make the aluminium membranous layer into the rugged structure, make it have sub-light characteristic, thus reduce the light reflectance of the aluminium membranous layer, dispel the optical feedback, promote the image intensifier and image the contrast.

Disclosure of Invention

The invention mainly aims to provide a sub-light fluorescent screen for an image intensifier and a preparation method thereof, which reduce the light reflectivity of the fluorescent screen by improving the preparation process of the fluorescent screen, further eliminate the light feedback phenomenon of the image intensifier and improve the imaging contrast of the image intensifier.

In order to achieve the above purposes, the technical scheme adopted by the invention is as follows: a sub-light fluorescent screen for an image intensifier comprises a fiber panel substrate, a fluorescent powder layer and an aluminum film layer.

Preferably, a substrate glue layer is prepared on the optical fiber panel base, and the glue used is ultrathin glue.

Preferably, the phosphor layer is brushed on the glue layer.

Preferably, the phosphor layer is dry-sprayed with an organic film, and the organic film solution is diluted and then sprayed onto the phosphor layer to attach to the edges of the phosphor particles, thereby forming an uneven structure.

Preferably, the aluminum layer is evaporated on the organic film layer twice.

The invention also provides a preparation method of the fluorescent screen, which comprises the following steps:

step 1: respectively preparing ultrathin gel, potassium silicate and organic film solution;

and 2, step: coating the ultrathin glue solution on the optical fiber panel substrate by a centrifugal method to prepare an ultrathin glue layer of the substrate;

and step 3: coating fluorescent powder on the substrate ultrathin glue layer by a brush coating method;

and 4, step 4: removing the substrate adhesive layer in an oven under a high temperature condition;

and 5: immersing the optical fiber panel substrate coated with the fluorescent powder in a potassium silicate solution, fishing out, spin-drying by a centrifugal method, and reinforcing the fluorescent powder layer;

step 6: spraying the organic film solution onto the fluorescent powder layer by a dry spraying method to form an organic film layer;

and 7: evaporating the aluminum film onto the organic film layer by using a vacuum evaporation device, wherein the thickness of the aluminum film is

And 8: removing the organic film in an oven under a high temperature condition;

and step 9: evaporating the aluminum film layer again by using vacuum evaporation equipment, wherein the thickness of the evaporated aluminum film layer is equal to

Step 10: inspecting the pinhole, crack, etc. of the fluorescent screen under a microscope by using transmitted light and oblique light;

step 11: checking fluorescent screen points, dark prints and the like by using an electron gun detector under a microscope;

step 12: cleaning the polishing flange plate by using polishing felt, polishing paste and a cotton swab;

step 13: and coating silver dots on the coating to obtain the matt fluorescent screen.

Preferably, when the ultrathin glue solution is prepared, raw materials such as butyl acetate, 2046 resin, dibutyl phthalate and isobutanol are selected for preparation.

Preferably, when preparing the organic film solution, polyvinyl alcohol, isopropanol, polyethylene oxide, acrylic resin, deionized water and the like are selected as raw materials.

Preferably, when the organic film solution is sprayed onto the phosphor layer by a dry spraying method, the organic film solution is diluted to form an irregular structure of a concavo-convex shape along edges of phosphor particles on the phosphor layer.

Preferably, the fluorescent powder is ZnS: Cu-Al fluorescent powder.

The mechanism of the invention is as follows:

if the concentration of the organic film solution is too high, the surface of the formed organic film layer is necessarily a flat structure. Therefore, the organic film solution needs to be diluted before being coated on the phosphor layer to form an organic film layer with a concave-convex structure along the edges of the phosphor particles. And then, aluminum is evaporated to form an aluminum film layer with a concave-convex surface structure on the organic film layer.

First of all, evaporation

And (4) placing the aluminum film with the thickness in an oven, and removing the organic film layer at high temperature. Re-evaporation plating

Thickness of the aluminum layer. The two-step evaporation is to remove the organic film easily if the evaporation is performed directly

The thickness of the aluminum film is too thick, so that the organic film cannot be completely removed; on the other hand, the organic film layer is penetrated by huge energy impact during aluminum evaporation, so that the fluorescent powder layer is damaged. The requirement of thinness when primary aluminum plating is carried out is to avoid the high energy from impacting the organic film layer so as to damage the fluorescent powder layer; on the other hand, the organic film layer is of an uneven surface structure, aluminum films with uniform thickness cannot be formed on the surface of the organic film during evaporation of aluminum, and as a result of actual evaporation, the aluminum films at the convex positions and the concave positions of the organic film layer are thick, so that the aluminum films are thin when the aluminum is plated for one time, and the aluminum film layer with the uneven surface structure can be formed.

Because the aluminum film layer has uneven structure, when light emitted by the fluorescent screen is emitted along the direction of the photocathode, the light is refracted along the normal direction on the concave-convex surface of the aluminum film layer, and finally, only a few parts or even no light energy reaches the photocathode. In addition, a small part of optical signals are mixed in the electronic signals input by the photocathode, and because the structure of the aluminum film layer is uneven, when the part of optical signals reaches the aluminum film layer, the part of optical signals are refracted along the normal direction of the concave-convex surface of the aluminum film layer, so that the part of light cannot be directly returned to the photocathode. In conclusion, the aluminum film layer is of a concave-convex uneven structure, so that visible light emitted by the fluorescent screen can be reduced and returned to the photocathode, and meanwhile, a small part of light signals input by the photocathode can be reduced and returned to the photocathode, and light feedback is reduced.

The invention has the beneficial effects that:

(1) the aluminum film layer of the fluorescent screen has a non-flat and uneven structure and has the matte characteristic, and the optical index can be greatly reduced, so that the optical feedback of the fluorescent screen is reduced, the imaging contrast of the image intensifier is improved, the image is clearer and more striking, and the color is more vivid and bright.

(2) The invention also provides a method for preparing the fluorescent screen, which has simple preparation process and low production cost and can effectively improve the production efficiency.

Drawings

Fig. 1 is a schematic diagram of the working principle of the micro-optical image intensifier.

FIG. 2 is a schematic view of the operating principle of the phosphor screen of the present invention.

In the figure: 1-optical fiber panel substrate, 2-fluorescent powder layer and 3-aluminum film layer.

Detailed Description

The following description is presented to disclose the invention so as to enable any person skilled in the art to practice the invention. The preferred embodiments in the following description are given by way of example only, and other obvious variations will occur to those skilled in the art.

As shown in fig. 2, the fluorescent screen for low-light level image intensifier of the invention is a multi-layer structure, comprising a fiber panel substrate 1, a phosphor layer 2 and an aluminum film layer 3.

The optical fiber panel substrate 1 adopts a small-diameter optical fiber panel to support the fluorescent powder layer 2 and the aluminum film layer 3. And the fluorescent powder layer 2 is used for converting an electronic image input by the photoelectric cathode into an optical image. The aluminum film layer 3, on one hand, emits the light generated by the fluorescent powder to the anode direction to increase the brightness of the light; on the other hand, the protective layer can be used for preventing the fluorescent powder layer from being polluted and poisoned by cesium vapor.

The working principle of the micro-optical image intensifier is shown in figure 1. The objective lens images a weak optical image on the optical fiber panel, the image is transmitted to a photocathode of an image intensifier through an input window of the optical fiber panel, a corresponding electronic image is generated by the photocathode, an electronic image beam is amplified through a microchannel plate, then is converted into an optical image with enhanced brightness through an anode high-voltage accelerated excitation fluorescent screen, and finally is output through an output window of the optical fiber panel. The whole image intensifier completes the conversion of 'inputting weak optical image → corresponding electronic image → high energy high beam current electronic image → outputting light image'. The working principle of the fluorescent screen for the image intensifier is shown in fig. 2, electrons penetrate through an aluminum film layer 3 to excite a fluorescent powder layer 2, the fluorescent powder absorbs the electrons and emits visible light, and a visible light image is output through an output window of an optical fiber panel substrate 1. As shown in fig. 2, the aluminum film layer has an uneven structure, which can reduce the visible light emitted from the fluorescent screen to return to the photocathode, and also can reduce a small portion of the optical signals input by the photocathode to return to the photocathode, thereby reducing the optical feedback.

The embodiment is as follows: the above screen can be prepared by the following route:

the invention provides a preparation method of a matte fluorescent screen for a low-light-level image intensifier. Firstly, selecting a small-wire-diameter optical fiber panel substrate and cleaning; uniformly coating the glue solution on the optical fiber panel substrate by adopting a centrifugal method to form a substrate glue layer; uniformly coating fluorescent powder (ZnS: Cu-Al micron fluorescent powder) on the substrate glue by a brush coating method to form a fluorescent powder layer; removing the glue layer in an oven at 400 ℃; immersing the powder layer into 5% potassium silicate solution to fix the powder layer; spraying the diluted organic film solution on the fluorescent powder layer to form an organic film layer; evaporating an aluminum film layer in a vacuum coating machine with a thickness of

Adding the organic film into an oven to remove the organic film; evaporating an aluminum film layer in a vacuum coating machine with the thickness of

After the aluminum plating process is finished, inspecting pinholes, cracks and the like of the fluorescent screen by using transmitted light and oblique light under a microscope; inspecting fluorescent screen dark spots, dark prints and the like by using a detector under an electron gun under a microscope; polishing the flange plate by using polishing felt and polishing paste to obtain a bright surface; and after the coating is qualified, coating silver dots on the coating. Thus, the sub-luminescent screen described in the present invention can be prepared.

The foregoing has described the general principles, principal features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are merely illustrative of the principles of the invention, but that various changes and modifications may be made without departing from the spirit and scope of the invention, which fall within the scope of the invention as claimed.

Claims (10)

1. The matt fluorescent screen for the low-light-level image intensifier is characterized by further comprising a fluorescent powder layer (2) on an optical fiber panel substrate (1) and an aluminum film layer (3) supported on the fluorescent powder layer (2), wherein the surface of the aluminum film layer (3) is uneven and has matt properties.

2. The matte screen for a micro-optic image intensifier according to claim 1, characterized in that a substrate glue layer is arranged between the fiber panel base (1) and the phosphor layer (2).

3. The matte screen for a micro-optical image intensifier according to claim 1 or 2, characterized in that between the phosphor layer (2) and the aluminum film layer (3), an organic film layer is also applied on the phosphor layer (2), and the phosphor layer (2) is strengthened with potassium silicate solution before the organic film layer is applied.

4. The sub-luminescent screen for micro-optical image intensifier as claimed in claim 1 or 2, wherein the substrate glue layer is prepared by selecting ultra-thin glue solution.

5. The matte screen for a low-light level image intensifier as claimed in claim 3, wherein the organic film solution is diluted before being sprayed on the phosphor layer (2) so as to form the irregular structure of the concavo-convex shape along the edges of the phosphor particles on the phosphor layer (2).

6. A method of manufacturing a matt fluorescent screen for a micro-optic image intensifier as claimed in any one of claims 1 to 5, comprising the steps of:

step 1, respectively preparing ultrathin glue, potassium silicate and organic film solution;

step 2, coating the ultrathin glue solution on the optical fiber panel substrate (1) by a centrifugal method to prepare a substrate ultrathin glue layer;

step 3, coating the fluorescent powder on the substrate ultrathin glue layer by a brush coating method;

step 4, removing the substrate adhesive layer in an oven under a high temperature condition;

step 5, immersing the optical fiber panel substrate coated with the fluorescent powder into potassium silicate solution, fishing out, spin-drying by a centrifugal method, and reinforcing the fluorescent powder layer (2);

step 6, spraying the organic film solution onto the fluorescent powder layer (2) by a dry spraying method to form an organic film layer;

step 7, evaporating the aluminum film to the organic film layer by using vacuum evaporation equipment;

step 8, removing the organic film in an oven at a high temperature;

step 9, evaporating the aluminum film layer (3) by using vacuum evaporation equipment again;

step 10, checking and confirming no fluorescent screen pinholes and cracks under a microscope by using transmitted light and oblique light;

step 11, checking a fluorescent screen by using an electron gun detector under a microscope to confirm that no dark spot or dark print exists;

step 12, cleaning the polishing flange plate by using a polishing felt, polishing paste and a cotton swab;

and step 13, coating silver dots on the coating to obtain the matt fluorescent screen.

7. The method of claim 5, wherein:

in the step 1, when preparing the ultrathin glue solution, selecting butyl acetate, 2046 resin, diacetone alcohol and isobutanol as raw materials for preparation; when preparing the organic membrane solution, polyvinyl alcohol, isopropanol, polyethylene oxide, acrylic resin and deionized water are selected as raw materials.

8. The method of claim 5, wherein:

in step 7, the aluminum film is evaporated by a vacuum evaporation apparatusTo the aluminum film on the organic film layer with a thickness of

9. The method of claim 5, wherein:

in step 9, the aluminum film layer is again deposited by vacuum deposition equipment to a thickness of

10. The method of any one of claims 6 to 9, wherein the fiber optic faceplate substrate (1) is selected from a small-gauge fiber optic faceplate; the fluorescent powder is ZnS-Cu-Al fluorescent powder.

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