TWI645012B - Bendable structure - Google Patents

Abstract

A flexible structure can achieve an internal radius of flexure less than or equal to 1 mm and can be flexed more than 50,000 times. The flexible structure includes two substrates and an optical glue. Optical glue is located between the two substrates to adhere to each other. After the two substrates are bonded with the optical glue, the total thickness is less than or equal to 100 microns and the storage modulus of the optical glue is less than or equal to 90 kPa, or the total thickness is less than or equal to 75 microns and the storage modulus of the optical glue is less than or equal to 250 kPa.

Description

Flexible structure

The present invention relates to a flexible structure, and more particularly, to a flexible structure of a display.

In recent years, major brand manufacturers in the market have successively launched flexible electronic device products. At present, in evaluating the technical development of flexible devices, polyimide has been initially proved to be the most suitable substrate type, but Studies of other materials or studies of stacking / electrical properties have not been fully implemented, so there is no evaluation data on the number of times the whole structure is flexible.

When a flexible device needs to include a display and its touch module, different modules need to be bonded with optical glue. Whether the flexible properties of the overall structure of the optical adhesive is affected by different types of optical adhesives has not been evaluated.

How to make the flexible device including the display and its touch module more reliable and reliable requires more efforts.

Therefore, one aspect of the present invention is to provide a flexible structure capable of achieving an inner radius of deflection of less than or equal to 1 millimeter and capable of being bent more than 50,000 times. The flexible structure includes two substrates and an optical glue. Optical glue is located on the two substrates In order to adhere to each other. The total thickness of the two substrates after being bonded with the optical adhesive is less than or equal to 100 microns and the storage modulus of the optical adhesive is less than or equal to 90 kPa.

According to an embodiment of the present invention, the material of the optical adhesive includes silicon, acrylic or polyurethane adhesive, and the material of the substrate includes polyimide, polyethylene terephthalate, polycarbonate, and cycloolefin copolymerization. Materials, polyethylene naphthalate or flexible glass.

Another aspect of the present invention is to provide a flexible structure capable of achieving an inner radius of deflection less than or equal to 1 mm and capable of being flexed more than 50,000 times. The flexible structure includes two substrates and an optical glue. Optical glue is located between the two substrates to adhere to each other. The total thickness of the two substrates after being bonded with the optical adhesive is less than or equal to 75 microns and the storage modulus of the optical adhesive is less than or equal to 250 kPa.

According to an embodiment of the present invention, the storage modulus of the optical adhesive is greater than or equal to 90 kPa.

According to an embodiment of the present invention, the material of the optical adhesive includes silicon, acrylic or polyurethane adhesive, and the material of the substrate includes polyimide, polyethylene terephthalate, polycarbonate, and cycloolefin copolymerization. Materials, polyethylene naphthalate or flexible glass.

Another aspect of the present invention is to provide a flexible structure, which can achieve an inner radius of deflection of less than or equal to 1 mm and can be flexed more than 20,000 times. The flexible structure includes two substrates and an optical glue. Optical glue is located between the two substrates to adhere to each other. The total thickness of the two substrates after being bonded with the optical adhesive is less than or equal to 150 microns and the storage modulus of the optical adhesive is less than or equal to 90 kPa.

According to an embodiment of the present invention, the material of the optical adhesive includes silicon, acrylic, or polyurethane adhesive, and the material of the substrate includes polyimide, Polyethylene terephthalate, polycarbonate, cyclic olefin copolymer, polyethylene naphthalate or flexible glass.

Another aspect of the present invention is to provide a flexible structure, which can achieve an inner radius of deflection of less than or equal to 1 mm and can be flexed more than 20,000 times. The flexible structure includes two substrates and an optical glue. Optical glue is located between the two substrates to adhere to each other. The total thickness of the two substrates after being bonded with the optical adhesive is less than or equal to 100 microns and the storage modulus of the optical adhesive is less than or equal to 250 kPa.

According to an embodiment of the present invention, the storage modulus of the optical adhesive is greater than or equal to 90 kPa.

According to an embodiment of the present invention, the material of the optical adhesive includes silicon, acrylic or polyurethane adhesive, and the material of the substrate includes polyimide, polyethylene terephthalate, polycarbonate, and cycloolefin copolymerization. Materials, polyethylene naphthalate or flexible glass.

To sum up, the specification data of the flexible structure substrate and the optical adhesive summarized by the present invention can be used by those skilled in the art to quickly select an appropriate material to achieve the required reliability of the number of flexures.

100‧‧‧ flexible structure

102‧‧‧Optical glue

104a‧‧‧Polyimide substrate

104b‧‧‧Polyimide substrate

106a‧‧‧Touch Module

106b‧‧‧Display Module

T‧‧‧Total thickness

R1‧‧‧ radius

R2‧‧‧radius

In order to make the above and other objects, features, advantages, and embodiments of the present invention more comprehensible, the detailed description of the drawings is as follows: FIG. 1 is a diagram illustrating the flexibility according to an embodiment of the present invention. A partial cross-sectional view of a structure; FIG. 2 is a schematic diagram showing a bending of a flexible structure according to an embodiment of the present invention; and FIG. 3 is a performance diagram of a storage modulus of an optical adhesive used in a flexible structure according to an embodiment of the present invention.

One aspect of the present invention is to provide an electronic device with a flexible structure with a touch display, so that the trust performance of the electronic device's bending or flexing function can be effectively improved.

Please refer to FIGS. 1 and 2 at the same time. FIG. 1 is a partial cross-sectional view of the flexible structure 100 according to an embodiment of the present invention; FIG. 2 is a diagram according to an embodiment of the present invention. Bending diagram of the flexible structure. At present, the selection of substrate materials in flexible electronic devices has initially confirmed that polyimide is a more suitable substrate. After the flexural test with a radius of 1 mm in this case, only polyimide was used. The substrate can pass 200,000 times, and the other substrates are damaged less than 100,000 times. When a touch display is included in an electronic device, an optical adhesive (Optical Clear Adhesive) is necessary to adhere the substrate, for example, the flexible structure 100 in FIG. 1 is adhered to the upper touch module 106a and the lower touch module 106a with an optical adhesive 102. Display module 106b. Since the above-mentioned modules usually require a substrate, and the best flexible substrate is currently a polyimide substrate, this case uses an optical glue 102 to adhere to a diimide substrate (104a, 104b) as the test structure. To meet the needs of most current flexible electronic devices.

Please refer to FIG. 2, the flexible structure of the present case includes a three-layer structure, and the optical glue 102 is located between the dimerimine substrates (104 a and 104 b) to adhere to each other. When the flexural test was performed with the above-mentioned flexible structure in this case, it was found that the degree of softness and hardness of the optical adhesive 102 was one of the factors affecting the result of the flexural test. Specifically and In other words, with a softer optical adhesive, when the total thickness T of the flexible structure is equal to 100 micrometers (μm), it can pass the deflection test with an inner radius of 1 mm and 200,000 times, but the flexibility of the harder optical adhesive is used. The structure cannot pass.

In addition, the damages in the above-mentioned bending test results are all in the outer layer structure. For example, as shown in FIG. 2, the damages in the bending test results are all on the polyimide substrate 104 a. After analysis, in the flexure test, the length of the inner arc caused by the flexure (that is, the inner edge of the polyimide substrate 104b) is a radius R1 * π, and the outer arc caused by the flexure (that is, the polyimide substrate 104a) The length of the outer edge) is the radius R2 * π, that is, (R1 + T) * π, and the difference between the inner and outer arcs is the total thickness T * π. The test results show that the larger the difference between the inner and outer arcs, the higher the damage rate of the polyimide substrate 104a of the outer arcs. Therefore, the gap between the inner and outer arcs is also one of the factors affecting the bending test results. Because the flexed product has a difference between the inner and outer arcs when it is actuated, the gap is the total thickness T * π, so the total thickness of the product must be somewhat different. Limit to avoid excessive differences that cause breaks.

Regarding the degree of softness and hardness of the optical gel 102, after testing and analysis in this case, the storage modulus (Storage Modulus) above -20 ° C was selected as the basis for judging the degree of softness and hardness, and the following four models A, B, C, and D were used Material for testing. Please also refer to Figure 3 and Table 1 below. After testing and comparison, at low temperatures, the storage modulus of Models C and D, which are mainly acrylic, exceeds 250 kPa. In the current test results, once the optical adhesive- The storage modulus above 20 ° C exceeds 250kPa. Even if the total thickness is reduced (for example, to less than 75 microns), the number of deflections is still less than 20,000 (the inner radius of deflection is 1 mm). In addition, Model A and B are optical adhesives mainly based on silicone and modified acrylic formulations. If the storage modulus above -20 ℃ is less than 250kPa, they can pass. Requirements for testing.

After testing and comparison, in addition to the above-mentioned materials, the material of the optical glue 102 can also be silicone, acrylic, or polyurethane, but it is not limited to this, as long as the optical glue- Storage modulus above 20 ° C less than 250kPa should be able to meet the preliminary requirements for the glue in this case.

In this case, tests were performed on various combinations of "storage modulus" and "total thickness" of a storage modulus of -20 ° C or higher of less than or equal to 250 kPa, and the results obtained are as follows.

When the storage modulus of -20 ° C or higher of the optical glue is less than or equal to 90kPa and the total thickness T is 100 microns (for example, the thickness of the optical glue is 50 microns, the thickness of the two substrates are each 25 microns), the inner radius of the deflection is 1 mm The number of deflections can exceed 200,000 times.

When the storage modulus of the optical adhesive is lower than or equal to 90kPa and the total thickness T is 150 micrometers (for example, the optical adhesive thickness is 50 micrometers, and the thickness of the two substrates is 50 micrometers each), the inner radius of the deflection is 1 millimeter. The number of deflections is less than 50,000.

When the storage modulus of the optical adhesive above -20 ℃ is greater than 90kPa and When the total thickness T is less than or equal to 250 kPa and the total thickness T is 75 micrometers (for example, the thickness of the optical adhesive is 25 micrometers, and the thickness of the two substrates is 25 micrometers each), the number of flexures with a radius of 1 mm can exceed 200,000 times.

When the storage modulus of the optical adhesive above -20 ° C is greater than 90kPa and less than or equal to 250kPa, and the total thickness T is 100 microns (for example, the thickness of the optical adhesive is 50 microns, and the thickness of the two substrates is 25 microns each), the inner radius of the deflection The number of deflections for 1 mm is less than 50,000.

If the above data is considered conservatively from the perspective of product reliability, the following specifications can be summarized when designing products.

When the storage modulus of the optical adhesive above -20 ° C is less than or equal to 90kPa and the total thickness T is less than or equal to 100 microns (for example, the thickness of the optical adhesive is less than or equal to 50 microns, and the thickness of each of the two substrates is less than or equal to 25 microns), the deflection The number of deflections with an inner radius of 1 mm or less can exceed 50,000.

When the storage modulus of the optical glue is higher than 90kPa and less than or equal to 250kPa, and the total thickness T is less than or equal to 75 microns (for example, the thickness of the optical glue is less than or equal to 25 microns, and the thickness of the two substrates is less than or equal to 25 microns) ), The number of deflections within a deflection radius of 1 mm or less can also exceed 50,000 times.

When the storage modulus of the optical adhesive above -20 ° C is less than or equal to 90kPa and the total thickness T is less than or equal to 150 microns (for example, the thickness of the optical adhesive is less than or equal to 50 microns, and the thickness of each of the two substrates is less than or equal to 50 microns), the deflection The number of deflections with an inner radius less than or equal to 1 mm can exceed 20,000 times.

When the storage modulus of the optical adhesive above -20 ° C is greater than 90kPa and less than or equal to 250kPa, and the total thickness T is less than or equal to 100 microns (for example The thickness of the optical adhesive is less than or equal to 50 micrometers, and the thickness of the two substrates is less than or equal to 25 micrometers each.

The specification data of the above two sets of deflection times is more than 20,000 times and the second set of deflection times is more than 50,000 times, which can be used by ordinary knowledgeable persons in this field to quickly select appropriate materials to achieve the required deflection times reliability.

The aforementioned faceplates with which the flexible structure can be matched can be, for example, various flexible flexible panels such as Organic Light-Emitting Diode, electronic paper, or electrophoretic display panel.

Although the above tests are mainly based on polyimide substrates, and only the polyimide substrates can pass the 200,000 tests, but in terms of the reliability of more than 20,000 or 50,000 deflections, other The base material can also be used. According to the test of the number of deflections of the inner radius of 1 mm in this case, the reliability of the substrate material can be more than 20,000 or 50,000 times. ), Cyclic olefin copolymers (Cyclo Olefin Polymers, COP), polyethylene naphthalate (Polythy-lene Naphtalate, PEN) or flexible glass, but it is not limited to this.

To sum up, the specification data of the flexible structure substrate and the optical adhesive summarized by the present invention can be used by those skilled in the art to quickly select an appropriate material to achieve the required reliability of the number of flexures.

Although the present invention has been disclosed as above with several embodiments, it is not intended to limit the present invention. Any person with ordinary knowledge in the technical field to which the present invention pertains can make various modifications without departing from the spirit and scope of the present invention. Changes and retouching, so the scope of protection of the present invention should be defined by the scope of the attached patent application Prevail.

Claims (10)

A flexible structure capable of achieving an internal radius of deflection of less than or equal to 1 mm and capable of being flexed more than 50,000 times. The flexible structure includes: two substrates; and an optical glue located between the two substrates to adhere to each other. The total thickness of the two substrates after being bonded with the optical adhesive is less than or equal to 100 microns, and the storage modulus of the optical adhesive above -20 ° C is less than or equal to 90 kPa. The flexible structure according to item 1 of the scope of the patent application, wherein the material of the optical glue comprises silicon glue, acrylic glue or polyurethane glue, and the material of the substrate comprises polyimide, polyethylene terephthalate , Polycarbonate, cycloolefin copolymer, polyethylene naphthalate or flexible glass. A flexible structure capable of achieving an internal radius of deflection of less than or equal to 1 mm and capable of being flexed more than 50,000 times. The flexible structure includes: two substrates; and an optical glue located between the two substrates to adhere to each other. The total thickness of the two substrates after being bonded with the optical adhesive is less than or equal to 75 microns, and the storage modulus of the optical adhesive above -20 ° C is less than or equal to 250 kPa. The flexible structure according to item 3 of the scope of the patent application, wherein the material of the optical glue comprises silicon glue, acrylic glue or polyurethane glue, and the material of the substrate comprises polyimide, polyethylene terephthalate , Polycarbonate, cycloolefin copolymer, polyethylene naphthalate or flexible glass. The flexible structure according to item 3 of the scope of patent application, wherein the storage modulus of the optical adhesive is greater than or equal to 90 kPa. A flexible structure capable of achieving an internal radius of deflection of less than or equal to 1 mm and capable of being flexed more than 20,000 times. The flexible structure includes: two substrates; and an optical glue located between the two substrates to adhere to each other. The total thickness of the two substrates after being bonded with the optical adhesive is less than or equal to 150 microns, and the storage modulus of the optical adhesive above -20 ° C is less than or equal to 90 kPa. The flexible structure according to item 6 of the scope of the patent application, wherein the material of the optical glue includes silicon glue, acrylic glue or polyurethane glue, and the material of the substrate comprises polyimide, polyethylene terephthalate , Polycarbonate, cycloolefin copolymer, polyethylene naphthalate or flexible glass. A flexible structure capable of achieving an internal radius of deflection of less than or equal to 1 mm and capable of being flexed more than 20,000 times. The flexible structure includes: two substrates; and an optical glue located between the two substrates to adhere to each other. The total thickness of the two substrates after being bonded with the optical adhesive is less than or equal to 100 microns, and the storage modulus of the optical adhesive above -20 ° C is less than or equal to 250 kPa. The flexible structure according to item 8 of the scope of the patent application, wherein the material of the optical glue comprises silicon glue, acrylic glue or polyurethane glue, and the material of the substrate comprises polyimide, polyethylene terephthalate , Polycarbonate, cycloolefin copolymer, polyethylene naphthalate or flexible glass. The flexible structure according to item 8 of the scope of patent application, wherein the storage modulus of the optical adhesive is greater than or equal to 90 kPa.