Resistive touch screen with three-layer structure

Abstract

The invention relates to a resistive touch screen with a three-layer structure. The resistive touch screen sequentially comprises a cover plate layer, a first conductive circuit layer, a rubber frame layer and a second conductive circuit layer, the cover plate layer is bonded with the first conductive circuit layer through optical cement; the first conductive circuit layer and the second conductive circuit layer are connected through the rubber frame layer, the rubber frame layer is provided with a sealable gas port, and a space between the rubber frame layers can be filled with gas through the gas port. The resistance-type touch screen of the three-layer structure is provided with an inflatable internal structure and is formed by the first conductive circuit layer and the second conductive circuit layer which are connected through the rubber frame layer, a gap exists between the first conductive circuit layer and the second conductive circuit layer and is supported by the filled gas, the phenomenon that the middle portion is close to the first conductive circuit layer and the second conductive circuit layer is not prone to occurring, and the touch effect is good. Therefore, Newton rings in the touch screen are avoided, and the product quality of the resistive touch screen is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of resistive touch screens, and in particular to a resistive touch screen with a three-layer structure. Background Art

[0002] The G+G (glass+glass) structure four-wire resistive touch screen consists of two layers of ITO (indium tin oxide) glass circuits, and its upper circuit is made of 0.2mm thick ITO glass. Compared with the traditional F+G (film+glass) structure four-wire resistive touch screen, it has an incomparable service life. The G+G structure four-wire resistive touch screen, because the upper layer is a glass structure, the ITO of the upper circuit set on the upper glass is very difficult to be worn during the use of the product, so the service life of this product can reach 20 years. This product is very popular in occasions where the product service life is extremely high.

[0003] However, the G+G (glass+glass) structure four-wire resistive touch screen also has serious weaknesses. One is poor impact resistance. That is, in order to ensure touch sensitivity, the ITO glass of the upper circuit cannot be thick and can only be developed in the direction of ultra-thin. If the ITO glass is too thin, its ability to resist mechanical impact will be poor and it will be easily broken by external impact. The second is that Newton rings are easily generated on the touch screen. Due to its own gravity, molecular force or electrostatic attraction, the ITO glass in the middle position is prone to natural bending, making the spacing between the upper and lower ITO glasses in the touch component uneven, thus generating Newton rings. Summary of the invention

[0004] Based on this, it is necessary to provide a three-layer resistive touch screen to address at least one of the above-mentioned problems.

[0005] The three-layer resistive touch screen provided by the present invention comprises: a cover layer, a first conductive circuit layer, a glue frame layer and a second conductive circuit layer in sequence; the cover layer and the first conductive circuit layer are bonded by optical glue;

[0006] The first conductive circuit layer and the second conductive circuit layer are connected via the glue frame layer. The glue frame layer is provided with a closable air port, through which gas can be filled into the space between the glue frame layers.

[0007] In one of the embodiments, a polyethylene terephthalate layer is disposed on the surface of the cover layer.

[0008] In one embodiment, the polyethylene terephthalate layer has a thickness of 0.2 mm.

[0009] In one embodiment, the optical adhesive is a UV optical adhesive.

[0010] In one of the embodiments, the optical adhesive has a thickness of 50 μm and a light transmittance greater than or equal to 98%.

[0011] In one embodiment, the first conductive circuit layer and the second conductive circuit layer both include indium tin oxide glass and silver wire circuits.

[0012] In one embodiment, the thickness of the indium tin oxide glass of the first conductive circuit layer is 0.2 mm, and the thickness of the indium tin oxide glass of the second conductive circuit layer is 0.7 mm or 1.1 mm.

[0013] In one embodiment, the first conductive circuit layer and the second conductive circuit layer are both connected to a flexible circuit board.

[0014] In one embodiment, the material of the glue frame layer includes epoxy resin and glass powder.

[0015] In one of the embodiments, the weight ratio of the epoxy resin to the glass powder is 5:1; and the maximum particle size of the glass powder is 9 μm.

[0016] The technical solution provided in the embodiments of the present invention brings the following beneficial technical effects:

[0017] The three-layer resistive touch screen provided by the present invention has an inflated internal structure, which is formed by a first conductive circuit layer and a second conductive circuit layer connected by a rubber frame layer. There is a gap between the first conductive circuit layer and the second conductive circuit layer, which is supported by the filled gas, so that the middle parts will not be close to each other easily, thereby avoiding the generation of Newton rings in the touch screen and improving the product quality of the resistive touch screen.

[0018] Additional aspects and advantages of the present application will be given in subsequent parts and will be understood in detail from the subsequent description or learned through specific implementations of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the layered structure of a three-layer resistive touch screen according to an embodiment of the present invention;

[0020] Figure 2 A schematic diagram of the planar structure of a three-layer resistive touch screen according to an embodiment of the present invention;

[0021] Figure 3 The schematic diagram is a planar structural diagram of a three-layer resistive touch screen after removing the cover plate and the first conductive circuit layer in one embodiment of the present invention.

[0022] Description of reference numerals:

[0023] 100-cover layer, 200-first conductive circuit layer, 300-glue frame layer, 400-second conductive circuit layer;

[0024] 110-optical glue, 310-air port. DETAILED DESCRIPTION

[0025] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Possible embodiments of the present invention are shown in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein by the drawings. The embodiments described with reference to the drawings are exemplary and are used to make the understanding of the disclosure of the present invention more thorough and comprehensive, and cannot be interpreted as limiting the present invention. In addition, if the detailed description of the known technology is non-essential technology for the features of the present invention shown, these technical details may be omitted.

[0026] It will be understood by those skilled in the relevant art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with those in the prior art, and will not be interpreted with idealized or overly formal meanings unless specifically defined as herein.

[0027] It will be understood by those skilled in the art that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present application refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. It should be understood that the term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items.

[0028] The technical solution of the present invention and how the technical solution solves the above-mentioned technical problems are described in detail below with specific embodiments.

[0029] The three-layer resistive touch screen provided by the present invention, as shown in the figure, includes: a cover layer 100, a first conductive circuit layer 200, a glue frame layer 300 and a second conductive circuit layer 400 from the surface of the touch screen to the inside; the cover layer 100 and the first conductive circuit layer 200 are bonded by an optical glue 110. That is, the resistive touch screen provided by the present invention adopts a three-layer structure design, and the main components are the cover layer 100 (called LENS in the industry, and will be used hereinafter), the upper conductive circuit and the lower conductive circuit. In one embodiment, a polyethylene terephthalate layer is provided on the surface of the cover layer 100. The polyethylene terephthalate layer is referred to as PET, and PET is provided on the surface of the LENS, or PET is directly used as the LENS, and the thickness of PET is 0.2mm. It can be used as a panel installed on the touch screen, printed with LOGO characters and other patterns required by customers, to meet the customer's requirements for simplifying the design of their complete product, and also has a certain explosion-proof performance, which can improve the mechanical impact resistance of the upper ultra-thin circuit (that is, the first conductive circuit layer 200).

[0030] The first conductive circuit layer 200 and the second conductive circuit layer 400 are connected through the rubber frame layer 300. The rubber frame layer 300 is provided with a closable air port 310. Through the air port 310, gas can be filled into the space between the rubber frame layers 300. The first conductive circuit layer 200 and the second conductive circuit layer 400 overlap and stack, are connected and supported by the rubber frame layer 300, and a certain gap is provided between them. Except for the air port 310 that can communicate with the outside world, the rest of the rubber frame layer 300 is a sealed structure, that is, a separation space is formed between the first conductive circuit layer 200 and the second conductive circuit layer 400. Gas, such as dry air, is introduced into the separation space through the air port 310. The air pressure can be slightly greater than that of the outside world. If the air port 310 is not closed, the gas in the separation space will be ejected outward. Therefore, through the inflated separation space, the first conductive circuit layer 200 and the second conductive circuit layer 400 maintain a balanced spacing to avoid the appearance of Newton rings.

[0031] The three-layer resistive touch screen provided by the present invention has an inflated internal structure, which is formed by a first conductive circuit layer 200 and a second conductive circuit layer 400 connected by a rubber frame layer 300. There is a gap between the first conductive circuit layer 200 and the second conductive circuit layer 400, which are supported by the filled gas, so that the middle parts will not be easily close to each other, thereby avoiding the generation of Newton rings in the touch screen and improving the product quality of the resistive touch screen.

[0032] Specifically, in one embodiment of the present invention, the optical adhesive 110 is a UV optical adhesive 110. UV optical adhesive 110, namely SCA, is more suitable for a wide range of bonding sizes than ordinary OCA, and is more advantageous for medium and large sizes, and has strong rework performance. The surface of SCA optical adhesive 110 is non-sticky, easy to operate during bonding, fast to adjust, and has high alignment and bonding accuracy. Furthermore, SCA optical adhesive 110 can flow under certain hot pressing conditions, and has a low bubble generation rate. SCA optical adhesive 110 is a neutral product, which is not eroded and damaged by external moisture and water vapor, and can protect the appearance of the product and the stability of the ITO circuit. In one of the optional implementations, the thickness of the optical adhesive 110 is 50μm, and the transmittance is greater than or equal to 98%. The use of SCA, due to its strong adhesive force, can ensure that the transmittance of the touch screen reaches more than 80%, and ensure the reliable connection between LEMS and the first conductive circuit layer 200.

[0033] Specifically, in another embodiment of the present invention, the first conductive circuit layer 200 and the second conductive circuit layer 400 both include indium tin oxide glass and silver wire circuits. Further, in another embodiment of the present invention, the thickness of the indium tin oxide glass of the first conductive circuit layer 200 is 0.2 mm, and the thickness of the indium tin oxide glass of the second conductive circuit layer 400 is 0.7 mm or 1.1 mm. In one embodiment, the first conductive circuit layer 200 and the second conductive circuit layer 400 are both connected to a flexible circuit board. The first conductive circuit layer 200 uses 0.2 mm thick tempered ITO glass, which is composed of ITO circuits and silver wire circuits, and has two lead wires connected to the external control circuit through conductive glue and FPC. Since this ultra-thin glass has a certain elasticity, the user touches the touch surface of the glass to make the conductive circuit of the upper layer contact the conductive circuit of the lower layer to achieve the touch function. The second conductive circuit layer 400 uses 0.7 mm or 1.1 mm thick ITO glass, which is composed of ITO circuits and silver wire circuits, and also has two lead wires connected to the external control circuit through FPC. The upper and lower layers of circuits together form a four-wire resistive touch screen, realizing the electrical functions of the four-wire resistive touch screen.

[0034] In combination with the aforementioned embodiments, in one of the specific implementations of the present invention, the material of the glue frame layer 300 includes epoxy resin and glass powder. More specifically, the weight ratio of epoxy resin to glass powder is 5:1; the maximum particle size of the glass powder is 9μm. Epoxy resin is printed on the four sides of the product to bond the upper and lower circuits. 9μm glass powder is evenly mixed into the epoxy resin, and the weight ratio of glass powder to epoxy resin is 1:5. After the upper and lower circuits are completed through the high-temperature pressing process, the distance between the upper and lower circuits is about 9μm. Such a distance can avoid the uniform spacing between the upper and lower circuits of the touch screen and avoid the generation of Newton rings, and can also reduce the operating force of the touch screen (because the spacing between the upper and lower circuits is small enough, the operator can apply a small force to the touch screen to make the upper and lower circuits contact and realize the touch function).

[0035] The three-layer resistive touch screen provided by the present invention is provided with a notch of annular epoxy resin glue to inflate the cavity of the touch screen in order to prevent the middle part of the touch screen from collapsing under the action of gravity and generating Newton rings. After the notch is inflated, the notch is sealed with sealing glue. When inflating, the notch of the epoxy resin glue of the product should be upward and placed in the middle of a clamp to avoid the collapse of the upper and lower circuits during inflation. After inflation, the air port 310 is sealed with epoxy resin, and the supporting effect of the gas can prevent the middle part of the touch screen from collapsing under the action of gravity.

[0036] It will be understood by those skilled in the art that the terms "first" and "second" discussed in this application are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0037] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0038] In the description of this specification, specific features, structures, materials or characteristics may be combined in an appropriate manner in any one or more embodiments or examples.

[0039] The above description is only a partial implementation method of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A three-layer resistive touch screen, characterized in that: Including: A cover layer, a first conductive circuit layer, a rubber frame layer, and a second conductive circuit layer; The cover plate layer and the first conductive circuit layer are bonded together by optical adhesive; The first conductive circuit layer and the second conductive circuit layer are connected via the glue frame layer. The glue frame layer is provided with a closable air port, through which gas can be filled into the space between the glue frame layers.

2. The three-layer resistive touch screen according to claim 1, characterized in that: A polyethylene terephthalate layer is arranged on the surface of the cover plate layer.

3. The three-layer resistive touch screen according to claim 1, characterized in that: The polyethylene terephthalate layer has a thickness of 0.2 mm.

4. The three-layer resistive touch screen according to claim 1, characterized in that: The optical adhesive is an ultraviolet optical adhesive.

5. The three-layer resistive touch screen according to claim 1, characterized in that: The optical adhesive has a thickness of 50 μm and a light transmittance greater than or equal to 98%.

6. The three-layer resistive touch screen according to claim 1, characterized in that: The first conductive circuit layer and the second conductive circuit layer both include indium tin oxide glass and silver wire circuits.

7. The three-layer resistive touch screen according to claim 6, characterized in that: The thickness of the indium tin oxide glass of the first conductive circuit layer is 0.2 mm, and the thickness of the indium tin oxide glass of the second conductive circuit layer is 0.7 mm or 1.1 mm.

8. The three-layer resistive touch screen according to claim 1, characterized in that: The first conductive circuit layer and the second conductive circuit layer are both connected to a flexible circuit board.

9. The three-layer resistive touch screen according to claim 1, characterized in that: The material of the glue frame layer includes epoxy resin and glass powder.

10. The three-layer resistive touch screen according to claim 1, characterized in that: The weight ratio of the epoxy resin to the glass powder is 5:1; and the maximum particle size of the glass powder is 9 μm.

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