CN103177656A - Flexible back plate for flexible display - Google Patents

Abstract

The invention relates to a flexible backplane of a flexible display, comprising a structural layer and a laying layer, the structural layer adopts a negative Poisson's ratio honeycomb structure, the laying layer is evenly laid on the central plane of the structural layer, and the structural layer adopts a shape memory polymer It is made of carbon fiber or its composite material, and the laying layer is made of carbon fiber, and the laying layer is provided with two electrode leads; when the two electrodes are energized, the laying layer generates heat, and the structural layer is heated to reach the glass transition temperature of the structural layer material , and apply an external force to the honeycomb structure to achieve the purpose of deforming the honeycomb. After the heating is stopped, the shape of the honeycomb can be fixed, and its size becomes larger in two directions, thereby increasing the size of the back plate; when it is subjected to unidirectional compression , its size shrinks in the plane, thereby reducing the size of the back plate; the negative Poisson's ratio honeycomb structure has double curvature characteristics. The invention has the characteristics of bendability, double curvature, impact resistance, shock resistance, intelligent driving, light weight and beautiful appearance.

Description

A flexible backplane for a flexible display

technical field

The invention relates to a flexible backplane of a flexible display.

Background technique

As a new generation of display devices, flexible displays are widely used in mobile phones, personal digital assistants (PDAs), digital cameras, car displays, notebook computers, wall-mounted TVs, and military fields due to their advantages of portability, light weight, and unfavorable breakage. It has very broad application prospects. The main technical challenge today lies in the manufacture of flexible thin film transistor substrates.

In the prior art, for flexible displays, polymer materials such as polyimide (Polyimide) are generally used as the material of the flexible substrate in the flexible display. Using this flexible substrate does not cause plasticity within a few millimeters of curvature radius. Deformation (permanent deformation), however, if it is bent beyond the range of elastic deformation, it will cause permanent deformation, and the deformed part will become white and turbid, which will affect its display quality. In addition, when the flexible substrate is bent, the electronic devices attached to the flexible substrate are squeezed or stretched. After repeated bending and deformation, the flexible substrate will be fatigued due to stress, making the electronic devices on the flexible substrate The device is damaged and the circuit is damaged, resulting in malfunction.

Negative Poisson's ratio materials are an emerging material research direction. Its characteristics are: when a negative Poisson's ratio material is stretched, it will expand perpendicular to the direction of the tensile stress instead of the usual contraction; when compressed, the material will shrink perpendicular to the direction of the stress instead of the usual expansion ; When subjected to bending, a hollow low-pressure zone (double curvature characteristic) will be formed inside the material, which can improve the back support of the material. At the same time, the structure also has comprehensive functions such as light weight, high specific strength, high specific stiffness, high shear modulus, impact resistance, and heat insulation. The special properties of negative Poisson's ratio materials make it gradually become a class of new materials worth paying attention to, with broad application space.

At the same time, with the discovery and use of new smart material shape memory polymers, we found that using this large deformation shape memory material can well solve some problems in the manufacture of flexible display substrates. When the shape memory polymer is below the transition temperature, it has the basic characteristics of the polymer; above the transition temperature, it can have a large deformation, and the deformation can be fixed, and at the same time, such deformation can be completely restored; shape memory The deformation of the polymer material can be intelligently driven according to the design; at the same time, its polymer material has excellent mechanical properties such as high specific strength and high specific stiffness that resin-based polymer materials have.

Contents of the invention

Based on the above deficiencies, the present invention discloses a flexible backplane of a flexible display, which utilizes the negative Poisson's ratio effect of a special honeycomb structure and the shape memory effect of a new smart material shape memory polymer and its composite material. When the external temperature influence factor reaches the glass transition temperature or melting transition temperature of the material, the size change or shape change may occur. Under the condition of lowering the temperature, the new shape can be fixed again. When the material reaches its After the transition temperature, the body of the support member and the bracket can automatically return to their original shape. And the above process can be repeated.

The technology adopted in the present invention is as follows:

A flexible backplane for a flexible display, comprising a structural layer and a laying layer, the structural layer adopts a negative Poisson's ratio honeycomb structure, the laying layer is evenly laid on the central plane of the structural layer, and the structural layer adopts a shape memory polymer or its composite The material of the laying layer is made of carbon fiber and its composite material, silicon carbide fiber and its composite material, copper wire, nickel wire or carbon-based nano-paper material, and the laying layer is provided with the lead ends of two electrodes; when the two electrodes are When electricity is applied, the laying layer generates heat, and the structural layer is heated to reach the glass transition temperature of the structural layer material, and an external force is applied to the honeycomb structure to achieve the purpose of deforming the honeycomb. After the heating is stopped, the shape of the honeycomb can be fixed, and its size can be adjusted in two directions. becomes larger, thereby increasing the size of the back plate; when it is subjected to unidirectional compression, its size shrinks in the plane, thereby reducing the size of the back plate; the negative Poisson’s ratio honeycomb structure has double curvature characteristic.

The present invention also has the following features:

1. The negative Poisson’s ratio honeycomb structure mentioned above adopts a chiral honeycomb structure with a negative Poisson’s ratio effect, including a plurality of rigid blocks and their connected ligaments that are evenly spaced from each other, and the change of its size depends on the bending of the connecting ligaments , each rigid layer block corresponds to the area where the pixel unit in the display function layer of the flexible display is located, and the gap between each rigid block can ensure that the electronic device in the adjacent block does not occur during the bending process of the flexible display. Collide and squeeze each other, so as to ensure that the flexible display can still be displayed normally after being bent many times.

2. The above-mentioned shape memory polymer material is shape memory polyurethane resin, polyurethane type shape memory polymer, isocyanate type shape memory polymer, styrene type shape memory polymer, epoxy type Thermoplastic shape memory polymers or thermoset shape memory polymers.

3. A high-elastic rubber ring is provided on the periphery of the above-mentioned structural layer.

4. The above-mentioned structural layer adopts three-ligament overchiral honeycomb, four-ligament overchiral honeycomb, four-ligament overchiral honeycomb or anti-honeycomb three-ligament overchiral honeycomb.

5. A flexible display using the flexible backplane of the above-mentioned flexible display.

The backplane of the flexible display provided by the present invention has the characteristics of being bendable, double-curvature, capable of dimensional changes, intelligently driven, lightweight and beautiful. Moreover, due to the particularity of its structure, when choosing a chiral honeycomb structure, it can be considered that it is provided with rigid layer blocks arranged at intervals to protect the electronic devices in the flexible display. Therefore, when the flexible display is bent, each The gap between the rigid layer blocks ensures that the electronic devices in adjacent blocks will not collide and squeeze each other during the bending process. In this way, the bending life of the flexible display can be extended. Compared with the ordinary honeycomb structure, the honeycomb structure with negative Poisson's ratio effect has the advantage of light weight and is easy to carry under the same bearing capacity. At the same time, the structure has the characteristics of shock resistance and shock resistance.

Description of drawings

Fig. 1 is the schematic diagram of structure of the present invention;

Fig. 2 is anti-cellular structure diagram;

Fig. 3 is the dimensional change diagram of the reverse honeycomb structure of Fig. 2;

Figure 4 is a chiral honeycomb structure,

Fig. 5 is the dimensional deformation figure a and b of the chiral honeycomb structure in Fig. 4;

Figure 6 is triligament backchiral honeycomb;

Figure 7 is a four-ligament chiral honeycomb;

Figure 8 is four ligament backchiral honeycomb;

Figure 9 is an anti-cellular triligament inverse chiral honeycomb.

Detailed ways

Below according to the accompanying drawing of the description, give an example to further illustrate:

Example 1

As shown in Figure 1, a flexible backplane for a flexible display includes a structural layer 2 and a laying layer 3. The structural layer adopts a negative Poisson’s ratio honeycomb structure, and the laying layer is evenly laid on the central plane of the structural layer. The structural layer Made of shape-memory polymer or its composite material, the laying layer is made of carbon fiber and its composite material, silicon carbide fiber and its composite material, copper wire, nickel wire or carbon-based nano-paper material, and the laying layer is provided with two electrodes Lead end 4; as shown in Figure 2, when the two electrodes are energized, the laying layer generates heat, the structural layer is heated to reach the glass transition temperature of the structural layer material, and an external force is applied to the honeycomb structure to achieve the purpose of deforming the honeycomb , the shape of the honeycomb can be fixed after heating is stopped, and its size becomes larger in two directions, thereby increasing the size of the back plate; as shown in Figure 3, when it is subjected to unidirectional compression, its size shrinks in the plane, Therefore, the size of the back plate is reduced; the negative Poisson's ratio honeycomb structure has double curvature characteristics.

Example 2

As shown in Figures 4-5, this embodiment is like Embodiment 1, and the negative Poisson's ratio honeycomb structure adopts a chiral honeycomb structure with a negative Poisson's ratio effect, including a plurality of rigid blocks 5 that are evenly spaced from each other and connected The ligament 1, the change of its size depends on the bending of the connecting ligament 1, each rigid layer block corresponds to the area where the pixel unit in the display function layer of the flexible display is located, and the gap between each rigid block can ensure that the flexible display During the bending process, there is no mutual collision and extrusion between electronic devices in adjacent blocks, so as to ensure that the flexible display can still be displayed normally after multiple bendings. And a highly elastic rubber ring can be set on the periphery of the structure layer to protect the structure and users. Furthermore, the honeycomb structure of the flexible display backplane designed by the present invention has designable structural dimensions, and if a chiral honeycomb structure is used, the designer can adjust the length of the circular area and ligaments as required.

Example 3

As shown in FIG. 6 , the difference between this embodiment and Example 2 is that the structural layer 2 is a triligamentous inverse chiral honeycomb.

Example 4

As shown in FIG. 7 , the difference between this embodiment and Example 2 is that the structural layer 2 is a four-ligament chiral honeycomb.

Example 5

As shown in FIG. 8 , the difference between this embodiment and Example 2 is that the structural layer 2 is a four-ligamentary inverse chiral honeycomb.

Example 6

As shown in FIG. 9 , the difference between this embodiment and Example 2 is that the structural layer 2 is an anti-cellular triligament inverse chiral honeycomb.

Example 7

Furthermore, the honeycomb structure of the flexible display backplane designed in the present invention has a double curvature characteristic, that is, when it is bent in one direction, the direction perpendicular to it does not bend in the opposite direction, but bends in the same direction. This feature makes the bending of the backboard fully conform to the shape of the human body, so that it can be shaped into beautiful decorations according to the needs of users, such as bracelets, pendants, etc., which are beautiful and easy to carry.

The flexible display backplane produced by this method, its special honeycomb structure endows the backplane with excellent deformation and mechanical properties, and at the same time, the use of shape memory materials solves the complexity, high labor cost, and Problems such as high material production cost and poor production efficiency. At the same time, the honeycomb structure has designability, so that the structure has its own rigid blocks spaced apart from each other, and each rigid layer block can correspond to the area where the pixel unit in the display function layer of the flexible display is located to ensure that the flexible display is in the same position. During the bending process, there is no mutual collision and extrusion between electronic devices in adjacent blocks, thereby prolonging the service life of the flexible display.

Claims (6)

1. A flexible backplane for a flexible display, comprising a structural layer and a laying layer, characterized in that: the structural layer adopts a negative Poisson’s ratio honeycomb structure, the laying layer is evenly tiled in the central plane of the structural layer, and the structural layer adopts a shape It is made of memory polymer or its composite material, and the laying layer is made of carbon fiber and its composite material, silicon carbide fiber and its composite material, copper wire, nickel wire or carbon-based nano-paper material, and the laying layer is provided with two electrode leads ; When the two electrodes are energized, the laying layer generates heat, the structural layer is heated to reach the glass transition temperature of the structural layer material, and an external force is applied to the honeycomb structure to achieve the purpose of deforming the honeycomb. After the heating is stopped, the shape of the honeycomb can be fixed. Its size becomes larger in two directions, thereby increasing the size of the back plate; when it is subjected to unidirectional compression, its size shrinks in the plane, thereby reducing the size of the back plate; the negative Poisson Compared with the honeycomb structure, it has double curvature characteristics. 2. The flexible backplane of a flexible display according to claim 1, characterized in that: the negative Poisson's ratio honeycomb structure adopts a chiral honeycomb structure with a negative Poisson's ratio effect, including a plurality of mutually averagely spaced The rigid block and its connected ligaments change in size depending on the bending of the connecting ligaments. Each rigid layer block corresponds to the area where the pixel unit in the display function layer of the flexible display is located. The distance between each rigid block The gap can ensure that the electronic devices in adjacent blocks do not collide and squeeze each other during the bending process of the flexible display, so as to ensure that the flexible display can still be displayed normally after multiple bendings. 3. The flexible backplane of a flexible display according to claim 1, wherein the shape memory polymer material is shape memory polyurethane resin, polyurethane type shape memory polymer, isocyanic acid Vinegar-based shape memory polymers, styrenic shape-memory polymers, epoxy-based thermoplastic shape-memory polymers, or thermosetting shape-memory polymers. 4. The flexible backplane of a flexible display according to claim 1 or 2, characterized in that: the structure layer adopts three-ligament reverse chiral honeycomb, four-ligament chiral honeycomb, four-ligament reverse chiral honeycomb or reverse honeycomb Triligamentous backchiral honeycomb. 5 . The flexible backplane of a flexible display according to claim 1 or 2 , wherein a highly elastic rubber ring is arranged on the periphery of the structural layer. 6 . 6. A flexible display using the flexible backplane of a flexible display according to any one of claims 1-3.

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