An ultrasonic generating screen using a polyimide film and a manufacturing method thereof

Abstract

An ultrasonic generator screen using a polyimide film and a manufacturing method thereof, the ultrasonic generator screen comprises a transparent substrate and a vibration film stretched on the outside of the transparent substrate; a first transparent electrode is provided on the inner side of the vibration film, a second transparent electrode is provided on the outer side of the transparent substrate, an air layer or a transparent insulating medium layer is sandwiched between the first transparent electrode and the second transparent electrode; the vibration film is a polyimide film sandwiched with reinforcing fibers; the vibration film is a fiber mesh pressed on the first layer of polyimide film, and a second layer of polyimide coating is coated on the fiber mesh, which forms an infiltration with the fiber mesh and the first layer of polyimide coating, and the fiber mesh is coated between the first layer of polyimide coating and the second layer of polyimide coating, and then completely cured to form a polyimide film sandwiched with reinforcing fibers. The present invention enables the vibration film to maintain good vibration characteristics, and prevents the vibration film from undergoing large deformation, thereby avoiding the first transparent electrode from breaking.

Description

Technical Field

[0001] The invention relates to the field of ultrasonic technology, and in particular to an ultrasonic generating screen using a polyimide film and a manufacturing method thereof. Background Art

[0002] Ultrasonic wave screen is a screen that emits ultrasonic waves, and can load ordinary sound signals into its ultrasonic waves, thereby realizing directional transmission of sound according to the directionality of ultrasonic waves. Ultrasonic wave screens are generally made transparent to be combined with display screens (such as LCD, OLED, LED screens) to achieve the common output of images and directional sounds.

[0003] The existing ultrasonic wave generating screen generally includes a transparent substrate and a vibrating membrane stretched on the outside of the transparent substrate (stretching is used to keep the vibrating membrane having good vibration characteristics), the inner side of the vibrating membrane and the outer side of the transparent substrate are respectively provided with a first transparent electrode and a second transparent electrode, there is an overlapping area between the first transparent electrode and the second transparent electrode, and a transparent insulating medium or air layer is sandwiched between the first transparent electrode and the second transparent electrode. When an alternating voltage in the ultrasonic frequency band is applied between the first transparent electrode and the second transparent electrode, an alternating electrostatic force can be generated between the first transparent electrode and the second transparent electrode, and the vibrating membrane will vibrate under the action of the electrostatic force and emit ultrasonic waves to the front of the screen. However, in order to ensure insulation and lightness (which is conducive to the vibration of the vibration membrane), the vibration membrane of this ultrasonic generating screen is generally made of colorless polyimide with a thickness of no more than 30μm, but the mechanical strength of the vibration membrane of this thickness is insufficient. After being tightened, it may undergo significant deformation (such as becoming loose) during use and storage, which can easily lead to the rupture of the first transparent electrode (the first transparent electrode is generally made of a relatively brittle indium tin oxide film), thereby causing a malfunction, making the durability of this ultrasonic generating screen insufficient. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an ultrasonic wave generator screen using a polyimide film and a manufacturing method thereof, wherein the ultrasonic wave generator screen can enable the vibration film to maintain good vibration characteristics and prevent the vibration film from being greatly deformed, thereby avoiding the first transparent electrode from being broken, thereby improving the durability of the ultrasonic wave generator screen. The adopted technical solution is as follows:

[0005] An ultrasonic generating screen using a polyimide film comprises a transparent substrate and a vibration membrane stretched on the outside of the transparent substrate; a first transparent electrode is provided on the inner side of the vibration membrane, a second transparent electrode is provided on the outer side of the transparent substrate, and an air layer or a transparent insulating medium layer is sandwiched between the first transparent electrode and the second transparent electrode; the characteristic is that the vibration membrane is a polyimide film sandwiched with reinforcing fibers.

[0006] When a voltage in the ultrasonic frequency band is applied between the first transparent electrode and the second transparent electrode, the vibrating membrane vibrates under the action of electrostatic force, thereby emitting ultrasonic waves towards the front of the screen. In the structure of this ultrasonic transparent screen, after the vibrating membrane is tightened, the tension is basically applied to the reinforcing fibers, enabling the vibrating membrane to maintain good vibration characteristics. Moreover, during use and storage, the reinforcing fibers can better maintain the tension of the vibrating membrane and prevent the vibrating membrane from undergoing large deformations (such as becoming slack). The polyimide attached to the reinforcing fibers is not affected by the tension, and the first transparent electrode plated on the polyimide film will not rupture due to the deformation of the vibrating membrane, making this ultrasonic generating screen have sufficient durability.

[0007] As a preferred embodiment of the present invention, the reinforcing fibers are in a mesh structure.

[0008] As a preferred embodiment of the present invention, the reinforcing fibers are carbon fibers.

[0009] As a further preferred embodiment of the present invention, the tow diameter of the carbon fiber is <5 μm. This can reduce the visibility of the reinforcing fibers to the naked eye and avoid affecting the transparency of the vibrating membrane.

[0010] As another preferred embodiment of the present invention, the reinforcing fibers are glass fibers.

[0011] As a further preferred embodiment of the present invention, the glass fibers are made of colorless polyimide. Specifically, the glass fibers are completely infiltrated by colorless polyimide, thereby not affecting the transparency of the vibrating membrane.

[0012] As a preferred embodiment of the present invention, the first transparent electrode and the second transparent electrode are ITO electrodes.

[0013] As a preferred embodiment of the present invention, the vibrating membrane is tightened outside the transparent substrate through a tightening structure. The tightening structure is arranged around the transparent substrate, and the tightening structure is directly connected to the reinforcing fibers.

[0014] As a further preferred embodiment of the present invention, the tightening structure is a frame-shaped fixing adhesive layer. The material of the fixing adhesive layer can be an ultraviolet curable resin.

[0015] As a further preferred embodiment of the present invention, a transparent insulating dielectric layer is provided between the middle region of the inner side surface of the vibrating membrane and the transparent substrate.

[0016] The present invention also provides a manufacturing method of the above ultrasonic generating screen, which is characterized in that it includes the following steps:

[0017] (1)Coat a layer of colorless polyimide or polyimide precursor coating on the surface of the glass mother board, and form the first polyimide coating through semi-curing;

[0018] (2)Press a layer of tensioned fiber mesh on the first polyimide film, and the fiber mesh is composed of reinforcing fibers;

[0019] (3)Coat another layer of colorless polyimide or polyimide precursor coating on the fiber mesh to form the second polyimide coating, which infiltrates with the fiber mesh and the first polyimide coating, wraps the fiber mesh between the first polyimide coating and the second polyimide coating, and then fully cures the second polyimide coating to form a polyimide film with reinforcing fibers sandwiched therein, obtaining a vibration film;

[0020] (4)Deposit a layer of ITO film on the surface of the vibration film and form a first transparent electrode through patterning;

[0021] (5)Coat an insulating dielectric material on the first transparent electrode to form a dielectric layer, and coat a fixing glue layer as a tensioning structure in the peripheral area of the dielectric layer on the surface of the vibration film;

[0022] (6)Deposit a layer of ITO film on the transparent substrate and form a second transparent electrode through patterning, then cover the transparent substrate with the second transparent electrode on the glass mother board, sandwich the first transparent electrode and the second transparent electrode between the transparent substrate and the vibration film, and then cure the fixing glue layer and the dielectric layer to bond the outer side surface of the transparent substrate and the second transparent electrode to the inner side surface of the vibration film through the fixing glue layer;

[0023] (7)Peel off all the material layers attached to the glass mother board from the glass mother board to obtain the ultrasonic transparent screen.

[0024] As a preferred solution of the present invention, the polyimide precursor used in the steps (1) and (3) is polyamic acid.

[0025] As a preferred solution of the present invention, in the steps (4) and (6), a metal film is deposited on the surface of the ITO film and patterned to form a metal peripheral circuit.

[0026] As a preferred solution of the present invention, the insulating dielectric material coated in the step (5) is silica gel.

[0027] As a preferred solution of the present invention, the material of the fixing glue layer coated in the step (5) is ultraviolet curable resin.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] In the structure of this ultrasonic transparent screen, after the vibration film is tightened, its tensile force is basically applied to the reinforcing fibers, enabling the vibration film to maintain good vibration characteristics. Moreover, during use and storage, the reinforcing fibers can better maintain the tensile force of the vibration film and prevent the vibration film from undergoing significant deformation (such as becoming slack). The polyimide attached to the reinforcing fibers is not affected by the tensile force, and the first transparent electrode plated on the polyimide film will not crack due to the deformation of the vibration film. Therefore, this ultrasonic generating screen has good durability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 FIG. is a schematic structural diagram of the ultrasonic transparent screen provided by a preferred embodiment of the present invention.

[0031] Figure 2 is Figure 1 a schematic cross-sectional view of

[0032] Figure 3 is Figure 1 a schematic exploded view of the structure of the ultrasonic transparent screen shown in

[0033] Figure 4 a schematic structural diagram of the vibration film in a preferred embodiment of the present invention.

[0034] Figure 5 a schematic flow chart of the manufacturing method provided by a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] As Figures 1-4 shown, this ultrasonic generating screen using a polyimide film includes a transparent substrate 1 and a vibration film 2 tightened outside the transparent substrate 1; a first transparent electrode 3 is provided on the inner side surface of the vibration film 2, a second transparent electrode 4 is provided on the outer side surface of the transparent substrate 1, and a transparent insulating dielectric layer 5 is interposed between the first transparent electrode 3 and the second transparent electrode 4; the vibration film 2 is a polyimide film 21 sandwiching reinforcing fibers 22.

[0036] In this embodiment, the reinforcing fibers 22 are in a mesh structure.

[0037] In this embodiment, the reinforcing fibers 22 are carbon fibers, and the filament diameter of the carbon fibers < 5 μm. This can reduce the visibility of the reinforcing fibers 22 to the naked eye and avoid affecting the transparency of the vibration film 2. In another embodiment, the reinforcing fibers 22 are glass fibers, and the material of the glass fibers is colorless polyimide. The glass fibers are completely infiltrated by the colorless polyimide, and thus will not affect the transparency of the vibration film 2.

[0038] In this embodiment, the first transparent electrode 3 and the second transparent electrode 4 are ITO electrodes.

[0039] In this embodiment, the vibrating membrane 2 is tensioned outside the transparent substrate 1 by a tensioning structure 6. The tensioning structure 6 is arranged around the transparent substrate 1, and the tensioning structure 6 is directly connected to the reinforcing fiber 22. The tensioning structure 6 is a frame-shaped fixing adhesive layer 61. A transparent insulating dielectric layer 5 is provided between the middle region of the inner side surface of the vibrating membrane 2 and the transparent substrate 1.

[0040] Reference Figure 5 , this embodiment also provides a manufacturing method of the above ultrasonic generating screen, including the following steps:

[0041] (1) Coat a layer of colorless polyimide or polyimide precursor (such as polyamic acid) coating on the surface of the glass mother board 10, and form the first polyimide coating 211 through semi-curing.

[0042] (2) Press a tensioned fiber mesh on the polyimide film. The fiber mesh is composed of reinforcing fibers 22.

[0043] (3) Coat another layer of colorless polyimide or polyimide precursor (such as polyamic acid) coating on the fiber mesh to form the second polyimide coating 212. It infiltrates with the fiber mesh and the first polyimide coating 211, wraps the fiber mesh between the first polyimide coating and the second polyimide coating 212, and then completely cures the second polyimide coating 212 to form a polyimide film 21 sandwiching the reinforcing fiber 22, obtaining the vibrating membrane 2.

[0044] (4) Deposit a layer of ITO film (i.e., indium tin oxide film) on the surface of the vibrating membrane 2 and pattern it to form the first transparent electrode 3 (a metal film can be further deposited on the surface of the ITO film and patterned to form a metal peripheral circuit).

[0045] (5) Coat an insulating dielectric material (such as silica gel) on the first transparent electrode 3 to form the dielectric layer 5. Coat a UV-curable resin on the peripheral area of the dielectric layer 5 on the surface of the vibrating membrane 2 as the fixing adhesive layer 61 of the tensioning structure 6.

[0046] (6) Deposit a layer of ITO film on the transparent substrate 1 and pattern it to form the second transparent electrode 4 (a metal film can be further deposited on the surface of the ITO film and patterned to form a metal peripheral circuit). Then cover the transparent substrate 1 with the second transparent electrode 4 on the glass mother board 10, sandwich the first transparent electrode 3 and the second transparent electrode 4 between the transparent substrate 1 and the vibrating membrane 2, and then cure the fixing adhesive layer 61 and the dielectric layer 5 to bond the outer side surfaces of the transparent substrate 1 and the second transparent electrode 4 to the inner side surface of the vibrating membrane 2 through the fixing adhesive layer 61.

[0047] (7) Peel all the material layers attached to the glass mother board 10 from the glass mother board 10 to obtain the ultrasonic transparent screen.

[0048] In addition, it should be noted that for the specific embodiments described in this specification, the names of their respective parts and the like can be different. Any equivalent or simple changes made according to the structure, features, and principles described in the inventive concept of this invention patent are included within the protection scope of this invention patent. Those skilled in the technical field to which this invention pertains can make various modifications or supplements to the described specific embodiments or use similar methods for substitution, as long as they do not deviate from the structure of this invention or exceed the scope defined by this claims book, they should fall within the protection scope of this invention.

Claims

1. An ultrasonic generating screen using a polyimide film, comprising a transparent substrate and a vibrating film tensioned outside the transparent substrate; a first transparent electrode is provided on the inner side surface of the vibrating film, a second transparent electrode is provided on the outer side surface of the transparent substrate, and an air layer or a transparent insulating dielectric layer is interposed between the first transparent electrode and the second transparent electrode; characterized in that: The vibration membrane is a polyimide membrane sandwiched with reinforcing fibers; the vibration membrane is tightened on the outside of the transparent substrate through a tightening structure, the tightening structure is arranged around the transparent substrate, and the tightening structure is directly connected to the reinforcing fibers, and the tightening structure is a frame-shaped fixed adhesive layer.

2. The ultrasonic generating screen using a polyimide film according to claim 1, wherein: The reinforcing fibers are in a mesh structure.

3. The ultrasonic generating screen using a polyimide film according to claim 1, wherein: The reinforcing fibers are carbon fibers, and the diameter of the carbon fibers is less than 5 μm.

4. The ultrasonic generating screen using a polyimide film according to claim 1, characterized in that: The reinforcing fiber is glass fiber.

5. The ultrasonic generating screen using a polyimide film according to claim 4, wherein: The material of the glass fiber is colorless polyimide.

6. An ultrasonic generating screen using a polyimide film according to any one of claims 1-5, characterized in that: The material of the fixed adhesive layer is ultraviolet light curing resin.

7. A manufacturing method of an ultrasonic generating screen using a polyimide film as described in any one of claims 1-6, characterized in that: The steps include: (1) coating a layer of colorless polyimide or polyimide precursor coating on the surface of the glass mother plate, and semi-curing to form a first layer of polyimide coating; (2) Pressing a taut fiber mesh on the polyimide film, the fiber mesh is composed of reinforcing fibers; (3) coating the fiber web with a layer of colorless polyimide or a polyimide precursor to form a second polyimide coating layer, which is infiltrated with the fiber web and the first polyimide coating layer, and the fiber web is wrapped between the first polyimide coating layer and the second polyimide coating layer, and the second polyimide coating layer is completely cured to form a polyimide film sandwiched with reinforcing fibers, thereby obtaining a vibration membrane; (4) coating a layer of ITO thin film on the surface of the vibration membrane and patterning it to form a first transparent electrode; (5) coating an insulating dielectric material on the first transparent electrode to form a dielectric layer, and coating a fixing adhesive layer as a tensioning structure on the peripheral area of ​​the dielectric layer on the surface of the vibration membrane; (6) coating a layer of ITO thin film on the transparent substrate and patterning it to form a second transparent electrode, and then covering the transparent substrate with the second transparent electrode on the glass mother board, so that the first transparent electrode and the second transparent electrode are sandwiched between the transparent substrate and the vibration film, and then curing the fixing glue layer and the dielectric layer so that the outer side surfaces of the transparent substrate and the second transparent electrode are bonded to the inner side surface of the vibration film through the fixing glue layer; (7) All material layers attached to the glass mother plate are peeled off from the glass mother plate to obtain the ultrasonic generating screen.

8. The manufacturing method of an ultrasonic generating screen using a polyimide film according to claim 7, characterized in that: The polyimide precursor used in step (1) and step (3) is polyamic acid; the insulating dielectric material applied in step (5) is silica gel; and the material of the fixed adhesive layer applied in step (5) is ultraviolet light curing resin.

9. The manufacturing method of an ultrasonic generating screen using a polyimide film according to claim 7, characterized in that: In the steps (4) and (6), a metal film is plated on the surface of the ITO film and patterned to form a metal peripheral circuit.

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