KR102398552B1 - Flexible display device having bending sensing device - Google Patents

Abstract

The present invention relates to a flexible display device having a bending sensing device capable of forming an external resistance together with a bending sensor inside the flexible display device to lower an output offset voltage and reduce a resistance value change according to a temperature change. At least one bending sensor is embedded in a bending region of a film (layer) in which tensile deformation occurs and/or a film (layer) in which shrinkage deformation occurs when a flexible display device composed of two films (layers) is bent, and the tensile One or more reference resistors are embedded in the film (layer) in which the deformation occurs and/or in the non-bending region of the film (layer) in which the shrinkage deformation occurs.

Description

Flexible display device having bending sensing device

The present invention relates to a flexible display device, and in particular, by forming an external resistance together with a bending sensor inside the flexible display device, it is possible to reduce an output offset voltage and reduce a change in resistance due to temperature change, as well as to prevent distortion. The present invention relates to a flexible display device having a bending sensing device capable of sensing.

The field of display that processes and displays a large amount of information has developed rapidly, and various display devices are being developed.

Examples of the display device include a liquid crystal display device (LCD), a plasma display panel device (PDP), a field emission display device (FED), and an electroluminescence display device (ELD). Luminescence Display Device), etc. have been developed, and these display devices are evolving in the direction of pursuing thinner, lighter, and lower power consumption. However, since the above-mentioned display devices use a glass substrate to withstand high heat generated during the manufacturing process, there is a limit in realizing lightweight and thinning or flexibility.

Accordingly, in recent years, a flexible display device manufactured to maintain display performance even when bent like paper by using a flexible material that can be folded and unfolded, such as a plastic film, instead of a conventional inflexible glass substrate is the next generation. It is emerging as a flat panel display device. Such a flexible display device is not only thin and light, but also has strong impact resistance, and can be bent or bent, so that it can be folded or rolled to be portable. In addition, since it has the advantage that it can be manufactured in various forms, its utility can be expanded in the future.

This flexible display technology has passed the experimental stage and is now on the verge of mass-production. The flexible display based on the flexible display is expected to provide a new type of input/output interface different from the conventional electronic devices having a rigid display, thereby providing a new user experience.

Recently, a device for detecting a shape of a flexible display capable of disposing a plurality of bending sensors at the edge of the flexible display device and detecting a shape of the flexible display device from the plurality of bending sensors has been proposed. There has been a bar (refer to Korean Patent Application Laid-Open No. 10-2014-0132569).

1 is a diagram illustrating a conventional flexible display device in which a plurality of bending sensors are disposed, and FIG. 2 is a diagram illustrating a configuration of a conventional measurement unit. 3A and 3B are diagrams illustrating a strain gauge circuit, and FIG. 4 is a block diagram illustrating a detailed configuration of the microprocessor of FIG. 2 .

Referring to FIG. 1 , bending sensors 101 and 102 capable of detecting bending of the flexible display panel are disposed along an edge (or edge) of the flexible display device 100 at regular intervals.

The bending sensors 101 and 102 are strain gauges. The strain gauge has a characteristic in which resistance between terminals changes according to physical elongation and contraction. In order to detect the shape of the flexible display device 100 using such a sensor, a measurement unit in charge of signal processing is required, which may be implemented as shown in FIG. 2 .

A conventional measurement unit may include a bridge circuit 210 , an amplifier 220 , an analog to digital converter (ADC) 230 , and the like.

The bridge circuit 210 is implemented as a Wheatstone bridge including one or more strain gauges. That is, since most of the resistance variations of the strain gauges are very small, as shown in FIG. 2 , a Wheatstone bridge is configured to convert a change in resistance into a change in voltage, and then amplify it through the amplifier 220 .

On the other hand, the Wheatstone bridge uses a quarter-bridge circuit for detecting a change in one strain gauge as shown in FIG. 3A, or the change in tension and contraction is reversed as shown in FIG. 3B. A half-bridge circuit is used to detect changes in a pair of strain gages. That is, when one strain gauge sensor is mounted on both sides of the arrangement position where each of the bending sensors 101 and 102 is disposed in the flexible display panel 100 of FIG. It is possible to obtain the effect of improving the sensitivity of the sensor.

On the other hand, when the bridge circuit 210 of FIG. 2 is configured as a quarter bridge circuit as shown in FIG. 3A , R1, R2, R3 and one strain gauge 330a may constitute the quarter bridge circuit 320a. In addition, when power is distributed to each resistor by the power supply of the power supply unit 310 , the magnitude of the voltage output from the bridge circuit varies according to a change in the resistance of the strain gauge 330a.

In addition, when the bridge circuit 210 of FIG. 2 is configured as a half-bridge circuit as shown in FIG. 3b, R1, R3 and two strain gauges 330b may constitute the half-bridge circuit 320b, When power is distributed to each resistor by the power supply of the power supply unit 310 , the magnitude of the voltage output from the bridge circuit changes according to a change in the resistance of each strain gauge 330b and 330c. The shape of the flexible display device is sensed by the voltage value output from the bridge circuit.

The output voltage of the bridge circuit 210 is input to the amplifier 220 , the small voltage change is amplified into a large voltage value, and then input to the analog-to-digital converter 230 . The analog-to-digital converter 230 converts an analog signal into a digital value and outputs it to a microprocessor 240 . The microprocessor 240 detects the shape of the flexible display panel 100 from measurement values sensed by the respective sensors.

A detailed configuration of the microprocessor 240 is shown in FIG. 4 .

That is, the microprocessor 240 includes a noise filter 402, a channel compensator 403, a curve point detector 404, and a VGA gain controller 405 ), a bending line detector (Bending Line Detector; 406), a slope compensator (Slope Compensator; 407), a feature extractor (408) and the like.

The noise filter unit 402 functions to filter a change in a sensor value caused by a factor other than a user's bending motion in the flexible display panel 100 from a meaningful signal.

The channel compensator 403 functions to compensate for a deviation between sensors disposed on the flexible display panel 100 , and may compensate for deviation between different sensors for each of the flexible display panels 100 . there is.

The inflection point detection unit 404 analyzes the measured values (eg, voltage values) sensed from the sensors 101 and 102 arranged in a line on each side (edge), and the inflection point formed on each edge (ie, each outer region) to extract the location and features of

The gain adjusting unit 405 is configured to output an amplifier (such as an output of each of the sensors 101 and 102 that is smaller than a predetermined reference value or out of an input range of the analog-to-digital converter 230 based on the output value of the inflection point detection unit 404). 220) (eg, a variable gain amplifier), when it is necessary to adjust the gain, an appropriate gain control signal is generated and provided to the amplifier 220 .

Meanwhile, the inflection point information detected from each of the outer regions 111 , 112 , 113 and 114 by the inflection point detector 404 is input to the bending line detector 406 and is used to detect the shape of the flexible display panel 100 .

The inclination compensator 407 compensates for bending information of the bending line based on the inclination information of the bending line.

The feature extracting unit 408 extracts the positions, slopes, angles, thicknesses, directions, etc. of the detected bending lines and transmits them to an upper layer.

However, the conventional bending sensing device and bending sensing method of the flexible display device have the following problems.

First, since the conventional bending sensing device of the flexible display device has a type in which the bending sensor is attached to the surface of the flexible display device, it is impossible to accurately sense the deformation of the entire flexible display device, and the stress and strain of each layer inside the flexible display device cannot be accurately measured. It cannot be measured and the deterioration characteristics of the display device according to time and environment cannot be predicted.

The reason is that, in the case of the strain gauge (SG) used in the prior art, the thickness is about 75㎛ (commercial product standard), and in order to adhere to the parent body, an additional special adhesive of several tens of ㎛ is required. When the thickness is reduced as in a flexible display device, the elasticity of the mother body is not mainly, but the elasticity of the SG is mainly, and the deformation of the matrix cannot be accurately sensed.

In addition, since the special adhesive between the matrix and SG has a different elastic modulus from the matrix and has viscous properties as well as elastic properties, the value measured in SG is not linear even if the matrix is linearly deformed.

Second, when the bridge circuit is configured as a quarter bridge circuit as shown in FIG. 3A , the bending sensor (strain gauge) is disposed at the edge of the flexible display device, and the remaining resistors R1, R2, and R3 are Since it is formed on the circuit board, an offset and tolerance are generated due to a difference in wiring length between the bending sensor (strain gauge) and the remaining resistors R1, R2, and R3.

When amplifying in a state having an offset value in this way, an input margin of the analog/digital converter is caused, and the digitally converted value becomes saturated.

Third, when the bridge circuit is configured as a half-bridge circuit as shown in FIG. 3B, the two bending sensors (two strain gauges) must be located at the position of the tensile strain state and the position of the contractile strain state. There is a downside to In this case, there may be restrictions in terms of system design.

Fourth, since the conventional flexible display device has a bending sensor attached to the surface of the flexible display device, routing lines for transmitting an output signal of each bending sensor are formed by a separate process or are separately required, such as FPC. production cost will increase.

Fifth, in the conventional flexible display device, since the bending portion has more flexibility than the other portions, the flexible display device may be twisted. can

The present invention is to solve the problems of the related art, and not only is a bending sensor built into the flexible display device, but also the external resistance is built into the flexible display device together with the bending sensor to increase the output offset voltage. An object of the present invention is to provide a flexible display device having a bending sensing device capable of lowering and reducing a change in a resistance value according to a temperature change, as well as detecting a twist of the flexible display device.

In a flexible display having a bending sensing device according to the present invention for achieving the above object, a film (layer) and/or contraction in which tensile deformation occurs when the flexible display device composed of a plurality of films (layers) is bent One or more bending sensors are embedded in a bending region of the film (layer) in which deformation occurs, and one or more bending sensors are embedded in a non-bending region of the film (layer) in which the tensile deformation occurs and/or the film (layer) in which the shrinkage deformation occurs. A reference resistor is built-in.

That is, one bending sensor is built in the bending region of the film (layer) in which the shrinkage deformation occurs, and one reference resistance is built in the non-bending region of the film (layer) in which the shrinkage deformation occurs, or the tensile deformation One bending sensor is embedded in the bending region of the film (layer) in which this occurs, and one reference resistance is embedded in the non-bending region of the film (layer) in which the tensile strain is generated.

Here, the signal detected by the one bending sensor is output through a bridge circuit, wherein the bridge circuit includes a first connection part in which R1 and R3 are connected in series through a first load between both ends of a power supply, and R2 and R4 are a second connection part connected in series through a second rod, the first connection part and the second connection part are connected in parallel to each other, an output terminal AB is provided between the first rod and the second rod, and the R1 to A selected one of R4 is configured as the one bending sensor, and a resistance adjacent to the selected one is configured as the reference resistance.

That is, R1 is composed of the one bending sensor, R2 or R3 is composed of the reference resistance, or R2 is composed of the one bending sensor, and R1 or R4 is composed of the reference resistance, R3 is configured as the single bending sensor, R1 or R2a is configured as the reference resistor, R4 is configured as the single bending sensor, and R1 or R2 is configured as the reference resistor.

Alternatively, a first bending sensor is embedded in a bending region of the film (layer) in which the shrinkage deformation occurs, and a first reference resistance is embedded in a non-bending region of the film (layer) in which the shrinkage deformation occurs, and the The second bending sensor may be embedded in a bending region of the film (layer) in which the tensile strain is generated, and the second reference resistance may be embedded in a non-bending region of the film (layer) in which the tensile strain is generated.

In this case, the first and second bending sensors may be built in one side of the bending area of the flexible display device or one at both sides of the bending area of the flexible display device.

As described above, when two bending sensors are built in the flexible display device, the signals detected by the first and second bending sensors are output through a bridge circuit, and the bridge circuit uses R1 and R3 between both ends of the power supply. A first connection portion connected in series through a first load and a second connection portion in which R2 and R4 are connected in series through a second load are provided, wherein the first connection portion and the second connection portion are connected in parallel to each other, and the first rod and An output terminal AB is provided between a second load, wherein R1 and R2 are the first and second bending sensors, and R3 and R4 are first and second reference resistors, or R1 and R3 is composed of the first and second bending sensors, R2 and R4 are composed of first and second reference resistors, or R3 and R4 are composed of the first and second bending sensors, and the R1 and R2 is composed of first and second reference resistors, R2 and R4 are composed of the first and second bending sensors, and R1 and R3 are composed of first and second reference resistances.

In another method, two bending sensors are built in the bending region of the film (layer) in which the shrinkage deformation occurs, and two reference resistors are built in the non-bending region of the film (layer) in which the shrinkage deformation occurs, or Two sensors may be embedded in a bending region of the film (layer) in which the tensile strain is generated, and two reference resistors may be embedded in a non-bending region of the film (layer) in which the tensile strain is generated.

As described above, when the two bending sensors are built in the flexible display device, signals detected by the two bending sensors are output through a bridge circuit, wherein R1 and R3 are connected to the first load between both ends of the power supply. A first connection part connected in series through and a second connection part where R2 and R4 are connected in series through a second load, wherein the first connection part and the second connection part are connected in parallel to each other, and the first load and the second An output terminal (AB) is provided between the rods, wherein R1 and R4 are the two bending sensors, and R2 and R3 are the two reference resistors, or R2 and R3 are the two bending sensors. and R1 and R4 may be composed of the two reference resistors.

In addition, in a flexible display having a bending sensing device according to the present invention for achieving the above object, one or more bending sensors are embedded in a bending region of the flexible display device to be inclined, and one or more bending sensors are installed in a non-bending region of the flexible display device. A reference resistor is embedded in a direction parallel to or perpendicular to the flexible display device.

Here, the bending sensor and the reference resistor are provided in two pieces, the first and second bending sensors are built in one side of the bending area, and the first and second reference resistors are also built in one side of the non-bending area.

Each of the bending sensor and the reference resistance includes two, a first bending sensor is built in one side of the bending area, a second bending sensor is built in the other side of the bending area, and the first reference resistance is at one side of the non-bending area. and a second reference resistor is built into the other side of the non-bending region.

The first bending sensor and the second bending sensor are installed to be inclined opposite to each other.

The flexible display device having the bending sensing device according to the present invention having the above characteristics has the following effects.

First, in the flexible display device having the bending sensing device of the present invention, since the bending sensor and the reference resistance are built in the flexible display device, the bending sensor and the reference resistance have the same tolerance range, and an output offset voltage value It is possible to lower the temperature and reduce the resistance deviation due to temperature change.

Second, in the flexible display device having the bending sensing device of the present invention, a bending sensor is embedded in a film in which tensile deformation occurs and a film in which shrinkage deformation occurs, so that a small change in resistance of the bending sensor is converted into a large output voltage and output. is improved, the double-a bending angle can be accurately measured, and it is easy to integrate UI/UX.

Third, in the present invention, since the bending sensor and the reference resistor are built in the flexible display device composed of a plurality of films (layers), the bending sensor and the bending sensor are conductive materials used in the process of the film (layer) in which the bending sensor is embedded. Since it is possible to form a routing line for outputting a signal detected in , an additional process is not required, and the unit cost can be reduced.

Fourth, since the bending sensor embedded in the bending area of the flexible display device is built in an inclined manner, normal bending and distortion can be distinguished and sensed.

1 is a view showing a conventional flexible display panel on which a plurality of bending sensors are disposed;
2 is a diagram showing the configuration of a conventional measurement unit;
3A and 3B show a strain gauge circuit, wherein FIG. 3A is a quarter-bridge circuit, and FIG. 3B is a half-bridge circuit diagram.
4 is a block diagram showing a detailed configuration of the microprocessor of FIG.
5 is an explanatory view for explaining the bending sensing principle of the flexible display device according to the present invention;
6 is an explanatory view for explaining a case in which a bending sensor and a reference resistor are mounted on one side or both sides of a bending area of the flexible display device according to the present invention;
7A is an explanatory diagram illustrating a bending sensor and a reference resistance embedded in a flexible display device according to the present invention, and FIG. 7B is an explanatory diagram illustrating a position in which the bending sensor and reference resistance according to the present invention are embedded in the flexible display device.
8 is an explanatory view for explaining a relationship between tension and contraction in a bending region in the flexible display device according to the present invention;
9A is a configuration diagram of a bridge circuit according to a first embodiment of the flexible display device having a bending sensing device according to the first embodiment of the present invention;
9B is a configuration diagram of a bridge circuit according to a second embodiment of the bending sensing device of the flexible display device according to the first embodiment of the present invention;
10A is a bridge circuit diagram of a third embodiment in a flexible display device having a bending sensing device according to a second embodiment of the present invention;
10B is a bridge circuit diagram of a fourth embodiment in a flexible display device having a bending sensing device according to a second embodiment of the present invention;
10C is a diagram illustrating a bridge circuit configuration of a fifth embodiment in a flexible display device having a bending sensing device according to a second embodiment of the present invention;
10D is a bridge circuit diagram of a sixth embodiment in a flexible display device having a bending sensing device according to a second embodiment of the present invention;
11 is an explanatory view for explaining a flexible display device having a bending sensing device according to a third embodiment of the present invention;
12A is a bridge circuit diagram of a seventh embodiment in a flexible display device having a bending sensing device according to a third embodiment of the present invention;
12B is a block diagram of a bridge circuit of an eighth embodiment in a flexible display device having a bending sensing device according to a third embodiment of the present invention;
13A to 13B are explanatory views when the bending area is normally bent at 90 degrees. 13b is a state diagram of the bending sensor when the bending sensor is built at the point where tensile deformation occurs and the bending area is not bent, and the state diagram when the bending sensor is built at the point where tensile deformation occurs and the bending area is normally bent.
14A to 14B are explanatory diagrams illustrating a case in which distortion occurs, and FIG. 14A is an explanatory diagram illustrating a case in which the flexible display device having the bending sensing device according to the second and third embodiments of the present invention is distorted; is the state diagram of the bending sensor when the bending sensor is built at the point where tensile deformation occurs and the bending area is not bent, and the state diagram when the bending sensor is built at the point where tensile deformation occurs and the bending area is warped
15A to 15B are explanatory diagrams for explaining changes in length and width of a bending sensor when a bending sensor is embedded in a bending region of a flexible display device to be inclined and the bending region is normally bent according to a fourth embodiment of the present invention; 15A is an explanatory diagram for explaining that the bending sensor is embedded in a bending area of the flexible display device to be inclined, and FIG. 15B is a state diagram and the bending sensor when the bending area is not bent when the bending sensor is embedded in the bending area to be inclined. When the bending area is built in an inclined way, the bending area is not distorted and is bent normally.
16A to 16B are explanatory diagrams for explaining changes in length and width of the bending sensor when the bending sensor is embedded in the bending area of the flexible display at an angle and distortion occurs in the bending area according to the fourth embodiment of the present invention; FIG. 16A is an explanatory diagram for explaining that the bending sensor is embedded in a bending area of the flexible display device to be inclined, and FIG. 16B is a first bending sensor when distortion occurs in the bending area in the inclined direction of the first bending sensor R1. A state diagram of (R1) and a state diagram of the second bending sensor R3 when distortion occurs in the bending region in the oblique direction of the first bending sensor R1
17 is a plan view illustrating a bending sensor and a reference resistance built in a flexible display device according to the second and third embodiments of the present invention;
18 is a plan view illustrating a bending sensor and a reference resistance built in a flexible display device according to a fourth embodiment of the present invention;

A flexible display device having a bending sensing device according to the present invention having the above characteristics will be described in more detail with reference to the accompanying drawings.

5 is an explanatory diagram for explaining the principle of an apparatus and method for sensing bending of a flexible display device according to the present invention, and FIG. 6 is a case in which bending sensors are mounted on one side or both sides of a bending area of the flexible display device according to the present invention. It is an explanatory diagram for explaining.

As shown in FIG. 5 , when the flexible display device is bent, stress (σ) and strain (ε) occur at the inflection point, and the stress (σ) and strain (ε) have a proportional relationship. is in When the flexible display device is bent, the thickness t, the width w, and the length L of the inflection point change according to the strain ε.

At this time, in the case of tensile deformation, the width w and the thickness t decrease and the length L increases, so that the resistance increases. In addition, in the case of shrinkage deformation, the width w and the thickness t increase and the length L decreases, so that the resistance decreases.

As shown in FIG. 6 , in a flexible display device having a bending sensing device according to the present invention, a bending sensor (BS) is built in one or both sides of a bending region of the flexible display device, and a reference resistance is provided in the non-bending region. (RR) is built-in.

7A is an explanatory diagram illustrating a bending sensor and a reference resistance embedded in the flexible display device of the present invention, and FIG. 7B is an explanatory diagram illustrating a position embedded in the bending sensor and the reference resistance flexible display device according to the present invention.

Both the bending sensor BS and the reference resistance RR according to the present invention are formed in the same shape as a conductive material having an electrical resistance, as shown in FIG. 7A . Accordingly, the bending sensor BS and the reference resistance RR are formed to have the same resistance value. However, since the bending sensor BS is formed in the bending area, the resistance value varies according to the degree of bending (bending angle), and the reference resistance RR is formed in the non-bending area, so the resistance value does not change.

In addition, as shown in FIG. 7B , the flexible display device according to the present invention includes a plurality of back plates, pixel arrays (TFT+Encap), touch sensors (Touch), and cover plates (Cover+Pol). It is composed of two films (layers).

Therefore, as described above, since the flexible display device is formed of a plurality of films (layers), the films or films (layers) in which tensile deformation and shrinkage deformation occur in the plurality of films (layers) in the bending region are different. As described above, since tensile strain and contractile strain are generated according to the position of the film or film (layer) in the bending region, the bending sensor (BS) and the reference resistance (RR) according to the present invention are the pixel array (TFT+Encap) of FIG. 7B . It will be embedded in one of the layer, the touch sensor layer and the cover plate (Cover +Pol) layer.

Here, the bending sensor BS and the reference resistance RR may be formed on different layers, but since the bending sensor BS and the reference resistance RR must have the same resistance value, they are preferably formed on the same layer. . However, the bending sensor (BS) is formed in a bending area, and the reference resistance RR is formed in a non-bending area.

8 is an explanatory diagram for explaining a relationship between tension and contraction in a bending region in the flexible display device according to the present invention.

First, it is considered that the flexible display device is composed of a plurality of films (layers) as described above, and FIG. 8 exemplifies that it is composed of four films (U1, U2, U3, U4). When such a flexible display device is bent, a depth at which tensile strain occurs in a thickness direction and a depth at which shrinkage strain occurs are different even in a bending region.

[Flexible display device having bending sensing device according to the first embodiment]

In FIG. 8 , when the flexible display device is bent toward the first film U1 , shrinkage deformation occurs in the third film U3 and tensile deformation occurs in the second film U2 .

Accordingly, in the flexible display device having the bending sensing device according to the first embodiment of the present invention, one bending sensor (strain gauge, BS) is built in one side of the bending area shown in FIG. 6 , and at least one bending sensor is built in the non-bending area. Built-in reference resistor (RR). At this time, the bending sensor BS and the reference resistance RR may be embedded in the third film U3 in which the shrinkage deformation described with reference to FIG. 8 occurs, and are embedded in the second film U2 in which the tensile deformation occurs. can be

9A is a block diagram of a bridge circuit of the first embodiment in the flexible display device having the bending sensing device according to the first embodiment of the present invention, and FIG. 9B is the flexible display having the bending sensing device according to the first embodiment of the present invention. It is a bridge circuit configuration diagram of the second embodiment in the device.

In the flexible display device having the bending sensing device according to the first embodiment of the present invention, the bridge circuit configuration of the first embodiment is, as shown in FIG. 9A , one bending sensor (strain gauge) R1 and three references. It consists of resistors R2, R3 and R4. A reference resistor R2 of the three reference resistors R2 , R3 , and R4 is built in the flexible display device, like the bending sensor. However, the present invention is not limited thereto, and the remaining reference resistors R3 and R4 may also be built in the flexible display device.

That is, as described in FIG. 8 , the bending sensor R1 is embedded in the bending region of the third film U3 in which the shrinkage deformation occurs or the second film U2 in which the tensile deformation occurs, and the shrinkage deformation is A reference resistance R2 is embedded in a non-bending region of the third film U3 or the second film U2 in which the tensile deformation occurs.

That is, a first connection part in which R1 and R3 are connected in series through a first load and a second connection part in which R2 and R4 are connected in series through a second load are provided between both ends of the power, and the first connection part and the second connection part A third film ( U3) or a reference resistance built in the non-bending region of the second film U2 in which the tensile deformation occurs.

When the bridge circuit is configured as shown in FIG. 9A , the voltage value V _AB between terminals AB is as follows.

Here, since R1 is a bending sensor that senses tensile strain or contraction strain, resistance varies when the flexible display device is bent, and even when the flexible display device is bent, R2 is formed in the non-bending region, so there is no change in resistance. Accordingly, since the bending sensor R1 and the reference resistor R2 are built into the flexible display device, the bending sensor R1 and the reference resistor R2 have the same tolerance range, and an output offset voltage value It is possible to lower the temperature and reduce the resistance deviation due to temperature change.

In addition, in the flexible display device having the bending sensing device according to the first embodiment of the present invention, as shown in FIG. 9B , in the bridge circuit configuration of the second embodiment, one bending sensor (strain gauge) R1 and three It consists of two reference resistors (R2, R3, R4). A reference resistor R3 among the three reference resistors R2 , R3 , and R4 is built in the flexible display device, like the bending sensor. However, the present invention is not limited thereto, and the remaining reference resistors R2 and R4 may also be built in the flexible display device.

That is, as described in FIG. 8 , the bending sensor R1 is embedded in the bending region of the third film U3 in which the shrinkage deformation occurs or the second film U2 in which the tensile deformation occurs, and the shrinkage deformation is The reference resistance R3 is built in the non-bending region of the third film U3 or the second film U2 where the tensile deformation occurs.

That is, a first connection part in which R1 and R3 are connected in series through a first load and a second connection part in which R2 and R4 are connected in series through a second load are provided between both ends of the power, and the first connection part and the second connection part A third film ( U3) or a reference resistance built in the non-bending region of the second film U2 in which the tensile deformation occurs.

When the bridge circuit is configured as shown in FIG. 9B , the voltage value (V _AB ) between terminals AB is as in [Equation 1].

V _AB = [R3 / ( R1 + R3 ) - R4 / (R2 + R4)] × Vs

Here, since R1 is a bending sensor sensing tensile strain or contraction strain, resistance varies when the flexible display device is bent, and R3 is formed in the non-bending region even when the flexible display device is bent, so there is no change in resistance. Therefore, since the bending sensor R1 and the reference resistor R3 are built in the flexible display device, the bending sensor R1 and the reference resistor R3 have the same tolerance range, and an output offset voltage value It is possible to lower the temperature and reduce the resistance deviation due to temperature change.

Although not shown in the drawings, in the bridge circuit of the first and second embodiments, high, the R2 may be configured as the bending sensor, the R1 or R4 may be configured as the reference resistor, and R3 may be the bending sensor , R1 or R2 may be configured as the reference resistor, R4 may be configured as the bending sensor, and R2 or R3 may be configured as the reference resistor.

That is, in the bridge circuit of the first and second embodiments, one of R1 to R4 may be configured as a bending sensor, and a resistance adjacent thereto may be configured as a reference resistance.

[Soft display device having bending sensing device according to the second embodiment]

In the flexible display device having the bending sensing device according to the second embodiment of the present invention, two bending sensors (strain gauges) are built in a bending region of one side of the flexible display device, and two standards are applied to a non-bending region of one side of the flexible display device. Resistors are built in, or one bending sensor (strain gauge) is built in each bending area on both sides of the flexible display device, and one reference resistor is built in each non-bending area on both sides of the flexible display device.

At this time, one bending sensor is embedded in the third film U3 in which the shrinkage deformation described with reference to FIG. 8 occurs, and the other bending sensor is embedded in the second film U2 in which the tensile deformation occurs.

10A is a block diagram of a bridge circuit of a third embodiment in a flexible display device having a bending sensing device according to a second embodiment of the present invention, and FIG. 10B is a flexible display having a bending sensing device according to a second embodiment of the present invention. It is a bridge circuit configuration diagram of a fourth embodiment in the device, FIG. 10C is a bridge circuit configuration diagram of a fifth embodiment in a flexible display device having a bending sensing device according to a second embodiment of the present invention, and FIG. 10D is a second embodiment of the present invention A bridge circuit diagram of the sixth embodiment in the flexible display device having the bending sensing device according to the second embodiment.

In the flexible display device having the bending sensing device according to the second embodiment of the present invention, the bridge circuit configuration of the third embodiment includes two bending sensors (strain gauges) R1 and R2 and two bending sensors (strain gauges) R1 and R2 as shown in FIG. It consists of two reference resistors R3 and R4. That is, as described in FIG. 8 , one bending sensor (strain gauge) embedded in the third film U3 in which the shrinkage deformation occurs is expressed as R2 in FIG. 10A, and the second film in which the tensile deformation occurs ( Another bending sensor (strain gauge) built into U2) is expressed as R1.

That is, a first connection part in which R1 and R3 are connected in series through a first load and a second connection part in which R2 and R4 are connected in series through a second load are provided between both ends of the power, and the first connection part and the second connection part are connected in parallel to each other, and in the bridge circuit in which the output terminal AB is formed at the first rod and the second rod, the R1 is configured as a bending sensor embedded in the second film U2 in which the tensile strain occurs, , R2 is constituted by one bending sensor (strain gauge) embedded in the third film U3 in which the shrinkage deformation occurs. In addition, the reference resistances R3 and R4 are composed of reference resistances respectively built in non-bending regions of the third film U3 in which the shrinkage deformation occurs and the second film U2 in which the tensile deformation occurs.

When the bridge circuit is configured as shown in FIG. 10A , the voltage value (V _AB ) between terminals AB is as in [Equation 1].

V _AB = [R3 / ( R1 + R3) - R4 / ( R2 + R4)] × Vs

Here, since R1 is a bending sensor sensing tensile strain, resistance increases, and R2 is a bending sensor sensing contraction strain, so resistance decreases. Accordingly, the output voltage of the bridge circuit according to the present invention is doubled compared to that of the conventional bridge circuit as shown in FIG. 3A.

In addition, since the bending sensors R1 and R2 and the reference resistors R3 and R4 are built into the flexible display device, the bending sensors R1 and R2 and the reference resistors R3 and R4 have the same tolerance range. , it is possible to lower the output offset voltage value and reduce the resistance deviation due to temperature change.

In the bridge circuit of FIG. 10A , one bending sensor (strain gauge) built into the third film U3 in which the shrinkage deformation occurs is configured as R1, and the second film U2 in which the tensile deformation occurs. It is okay to configure the other built-in bending sensor (strain gauge) as R2.

Meanwhile, in the flexible display device having the bending sensing device according to the second embodiment of the present invention, as shown in FIG. 10B , the bridge circuit configuration of the fourth embodiment includes two bending sensors (strain gauges) R1 and R3. and two reference resistors (R2, R4). That is, as described in FIG. 8 , one bending sensor (strain gauge) embedded in the third film U3 in which the shrinkage deformation occurs is expressed as R1 in FIG. 10A, and the second film in which the tensile deformation occurs ( Another bending sensor (strain gauge) built into U2) is expressed as R3.

That is, a first connection part in which R1 and R3 are connected in series through a first load and a second connection part in which R2 and R4 are connected in series through a second load are provided between both ends of the power, and the first connection part and the second connection part are connected in parallel to each other, and in the bridge circuit in which an output terminal AB is formed at the first rod and the second rod, one bending sensor embedded in the third film U3 in which the shrinkage deformation occurs, R1 ( strain gauge), and the R3 is configured as a bending sensor embedded in the second film U2 in which the tensile strain occurs. In addition, the reference resistances R3 and R4 are composed of reference resistances respectively built in non-bending regions of the third film U3 in which the shrinkage deformation occurs and the second film U2 in which the tensile deformation occurs.

When the bridge circuit is configured as shown in FIG. 10B, the voltage value (V _AB ) between the AB terminals is the same as Equation 1 above, R3 is a bending sensor that senses tensile strain, so the resistance increases, and R1 is a contraction strain As it is a bending sensor that senses, the resistance decreases. Accordingly, the output voltage of the bridge circuit according to the present invention is doubled compared to that of the conventional bridge circuit as shown in FIG. 3A.

In addition, since the bending sensors R1 and R3 and the reference resistors R2 and R4 are built into the flexible display device, the bending sensors R1 and R2 and the reference resistors R3 and R4 have the same tolerance range. , it is possible to lower the output offset voltage value and reduce the resistance deviation due to temperature change.

In the bridge circuit of FIG. 10B, one bending sensor (strain gauge) built into the third film U3 in which the shrinkage deformation occurs is configured as R3, and the second film U2 in which the tensile deformation occurs. It is okay to configure the other built-in bending sensor (strain gauge) as R1.

Meanwhile, in the flexible display device having the bending sensing device according to the second embodiment of the present invention, the bridge circuit configuration of the fifth embodiment includes two bending sensors (strain gauges) R3 and R4 as shown in FIG. 10C . and two reference resistors R1 and R2. That is, as described in FIG. 8 , one bending sensor (strain gauge) embedded in the third film U3 in which the shrinkage deformation occurs is expressed as R3 in FIG. 10c, and the second film in which the tensile deformation occurs ( Another bending sensor (strain gauge) built into U2) is expressed as R4.

That is, a first connection part in which R1 and R3 are connected in series through a first load and a second connection part in which R2 and R4 are connected in series through a second load are provided between both ends of the power, and the first connection part and the second connection part is connected in parallel to each other, and in the bridge circuit in which the output terminal AB is formed at the first rod and the second rod, one bending sensor embedded in the third film U3 in which the shrinkage deformation occurs, R3 ( strain gauge), and the R4 is configured as a bending sensor built into the second film U2 in which the tensile strain occurs. In addition, the reference resistances R1 and R2 are composed of reference resistances respectively built in non-bending regions of the third film U3 in which the shrinkage deformation occurs and the second film U2 in which the tensile deformation occurs.

When the bridge circuit is configured as shown in FIG. 10C, the voltage value (V _AB ) between the AB terminals is the same as in [Equation 1], R3 is a bending sensor that senses the contraction strain, so the resistance decreases, and R4 is the tensile strain As it is a bending sensor that senses, the resistance increases. Accordingly, the output voltage of the bridge circuit according to the present invention is doubled compared to that of the conventional bridge circuit as shown in FIG. 3A.

In addition, since the bending sensors R3 and R4 and the reference resistors R1 and R2 are built in the flexible display device, the bending sensors R3 and R4 and the reference resistors R1 and R2 have the same tolerance range. , it is possible to lower the output offset voltage value and reduce the resistance deviation due to temperature change.

In the bridge circuit of FIG. 10C, one bending sensor (strain gauge) built into the third film U3 where the shrinkage deformation occurs is configured as R4, and the second film U2 where the tensile deformation occurs is It is okay to configure the other built-in bending sensor (strain gauge) as R3.

Meanwhile, in the flexible display device having the bending sensing device according to the second embodiment of the present invention, in the bridge circuit configuration of the sixth embodiment, as shown in FIG. 10D , two bending sensors (strain gauges) R2 and R4 and two reference resistors (R1, R3). That is, as described in FIG. 8 , one bending sensor (strain gauge) embedded in the third film U3 in which the shrinkage deformation occurs is expressed as R2 in FIG. 10d, and the second film in which the tensile deformation occurs ( Another bending sensor (strain gauge) built into U2) is expressed as R4.

That is, a first connection part in which R1 and R3 are connected in series through a first load and a second connection part in which R2 and R4 are connected in series through a second load are provided between both ends of the power, and the first connection part and the second connection part is connected in parallel to each other, and in the bridge circuit in which an output terminal AB is formed at the first rod and the second rod, one bending sensor embedded in the third film U3 in which the shrinkage deformation occurs ( strain gauge), and the R4 is configured as a bending sensor built into the second film U2 in which the tensile strain occurs. In addition, the reference resistances R1 and R3 are composed of reference resistances respectively built in non-bending regions of the third film U3 in which the shrinkage deformation occurs and the second film U2 in which the tensile deformation occurs.

When the bridge circuit is configured as shown in FIG. 10D , the voltage value (V _AB ) between the AB terminals is the same as in [Equation 1], R2 is a bending sensor that senses the shrinkage strain, so the resistance is reduced, and R4 is the tensile strain As it is a bending sensor that senses, the resistance increases. Accordingly, the output voltage of the bridge circuit according to the present invention is doubled compared to that of the conventional bridge circuit as shown in FIG. 3A.

In addition, since the bending sensors R2 and R4 and the reference resistors R1 and R3 are built in the flexible display device, the bending sensors R2 and R4 and the reference resistors R1 and R3 have the same tolerance range. , it is possible to lower the output offset voltage value and reduce the resistance deviation due to temperature change.

In the bridge circuit of FIG. 10D , one bending sensor (strain gauge) built into the third film U3 in which the shrinkage deformation occurs is configured as R4, and the second film U2 in which the tensile deformation occurs. It is okay to configure the other built-in bending sensor (strain gauge) as R2.

[Flexible display device having bending sensing device according to the third embodiment]

11 is an explanatory diagram for explaining a flexible display device having a bending sensing device according to a third embodiment of the present invention, and FIG. 12A is a third embodiment of the flexible display device having a bending sensing device according to the third embodiment of the present invention. A bridge circuit configuration diagram according to a seventh embodiment, and FIG. 12B is a bridge circuit configuration diagram according to an eighth embodiment in a flexible display device having a bending sensing device according to a third embodiment of the present invention.

As shown in FIG. 11, in the flexible display device having a bending sensing device according to a third embodiment of the present invention, two bending sensors are embedded in a bending region of the second film U2 in which tensile deformation occurs, Two reference resistances are embedded in a non-bending region of the second film U2 in which the tensile deformation occurs, or the two bending sensors are embedded in a bending region of the third film U3 in which the contractile deformation occurs, 2 The reference resistances are built in the non-bending region of the third film U3 where the shrinkage deformation occurs.

11 shows that the two bending sensors are built in the bending area of the third film U3 in which the shrinkage deformation occurs. Although not shown in FIG. 11 , it can be sufficiently deduced that the two bending sensors are embedded in the bending region of the second film U2 in which tensile deformation occurs.

In addition, in the flexible display device having a bending sensing device according to the third embodiment of the present invention, the bridge circuit configuration of the seventh embodiment includes two bending sensors (strain gauges) R1 and R4, as shown in FIG. 12A . and two reference resistors (R2, R3).

In Fig. 11, two bending sensors built in the bending region of the second film U2 in which the tensile deformation occurs or two bending sensors embedded in the bending region of the third film U3 in which the contractile deformation occurs ( strain gauge) is expressed as R1 and R4 in FIG. 12A, and two reference resistances embedded in the non-bending region of the second film U2 in which the tensile deformation occurs or the third film U3 in which the shrinkage deformation occurs. Two reference resistors built in the non-bending region of , are expressed as R2 and R3 in FIG. 12A.

That is, a first connection part in which R1 and R3 are connected in series through a first load and a second connection part in which R2 and R4 are connected in series through a second load are provided between both ends of the power, and the first connection part and the second connection part are connected to each other in parallel, and in a bridge circuit in which an output terminal AB is formed at the first rod and the second rod, the R1 and R4 are embedded in a bending region of the third film U3 in which the shrinkage deformation occurs It is composed of two bending sensors (strain gauges) or two bending sensors embedded in the bending region of the second film U2 in which the tensile strain occurs.

When the bridge circuit is configured as shown in FIG. 12A, as described above, the output voltage of the bridge circuit according to the present invention is doubled compared to the conventional bridge circuit shown in FIG. 3A, and the bending sensor and the reference resistance are It has the same tolerance range, and it is possible to reduce the output offset voltage value and reduce the resistance deviation due to temperature change.

Meanwhile, in the flexible display device having the bending sensing device according to the third embodiment of the present invention, the bridge circuit configuration of the eighth embodiment is, as shown in FIG. 12B , two bending sensors (strain gauges) R2, R3) and two reference resistors (R1, R4).

In FIG. 11, two bending sensors embedded in the bending region of the second film U2 in which the tensile deformation occurs or two bending sensors embedded in the bending region of the third film U3 in which the contractile deformation occurs ( strain gauge) is expressed as R2 and R3 in FIG. 12B, and two reference resistances embedded in the non-bending region of the second film U2 in which the tensile deformation occurs or the third film U3 in which the shrinkage deformation occurs Two reference resistors built in the non-bending region of , are expressed as R1 and R4 in FIG. 12B .

That is, a first connection part in which R1 and R3 are connected in series through a first load and a second connection part in which R2 and R4 are connected in series through a second load are provided between both ends of the power, and the first connection part and the second connection part are connected in parallel to each other, and in a bridge circuit in which an output terminal AB is formed at the first rod and the second rod, the R2 and R3 are embedded in a bending region of the third film U3 in which the shrinkage deformation occurs It is composed of two bending sensors (strain gauges) or two bending sensors embedded in the bending region of the second film U2 in which the tensile strain occurs.

When the bridge circuit is configured as shown in FIG. 12B, as described above, the output voltage of the bridge circuit according to the present invention is doubled compared to the conventional bridge circuit shown in FIG. 3A, and the bending sensor and the reference resistance are It has the same tolerance range, and it is possible to reduce the output offset voltage value and reduce the resistance deviation due to temperature change.

In each embodiment of the present invention described above, it is possible to form a bending sensor and a routing line for outputting a signal detected by the bending sensor with the conductive material used in the process of the film (layer) in which the bending sensor is embedded.

For example, assuming that the film (layer) in which the shrinkage deformation occurs is the pixel array (TFT+Encap) layer, and the film (layer) in which the tensile deformation occurs is the touch sensor (Touch) layer, transistors constituting the pixel array A bending sensor and routing line can be formed with the material forming the gate electrode, data electrode, scan line and data line of can do.

As a result of the experiment of the present invention, when the reference resistor is in the board circuit as shown in FIG. 3A, the offset of the output voltage is -0.123 mV to 0.135 mV, whereas when the reference resistor is built in the flexible display device as in the present invention, The offset of the output voltage ranges from -0.004 mV to 0.004 mV, and it can be seen that the offset of the output voltage according to the present invention is reduced by about 97% compared to the offset of the conventional output voltage.

However, in the flexible display device having the bending sensing device according to each embodiment of the present invention as described above, when the bending sensor as shown in FIG. 7A is installed in the bending area, the bending area is not bent but is distorted (torsioned) in the bending area When this occurs, it may not be possible to measure the exact bending angle.

[Flexible display device having bending sensing device according to the fourth embodiment]

13A to 13B are explanatory views when the bending area is normally bent at 90 degrees. 13b is a state diagram of the bending sensor when the bending sensor is built at the point where tensile deformation occurs and the bending area is not bent, and the state diagram when the bending sensor is built at the point where tensile deformation occurs and the bending area is normally bent. .

That is, as described in the bending sensing device according to the second and third embodiments of the present invention, the bending sensor has two bending sensors (strain gauges) in a bending area on one side of the flexible display device in a direction perpendicular to the flexible display device. ) and two reference resistors are built-in in the non-bending area of one side of the flexible display device, or one bending sensor (strain gauge) is built in each bending area on both sides of the flexible display device and the ratio of both sides of the flexible display device is built in. One reference resistor may be built in each of the bending regions.

In FIG. 13A, two bending sensors (strain gauges) are expressed as R1 and R3, and two reference resistances are expressed as R2 and R4.

In this configuration, when the bending region of the soft display device is not bent, the bending sensor R1 or R3 has a length L, a width W, and a thickness t as shown in FIG. 13B . Also, when the bending region of the flexible display device is bent, the bending sensor R1 or R3 has a length L′, a width W′, and a thickness t′ as shown in FIG. 13B . That is, as described above, when the bending sensor is built at a point where tensile deformation occurs and the bending region of the flexible display device is bent, the length of the bending sensor R1 or R3 increases (L→L′) , the thickness and width decrease (W→W', t→t') to increase the resistance.

When the bending region is bent as described above, the length (L'), width (w'), and thickness (t') of the bending sensor R1 or R3 are expressed by an equation using the characteristics described in FIG. 5 . As follows.

In the above formula, in consideration of the values of length (L, L'), width (W, W') and thickness (t, t'), strain (ε) and resistance change ((R-R') )/R) is calculated.

Calculating in this way, when the strain ε is 1% (0.01) and the resistance change rate of the two bending sensors R1 and R3 is 1.68% (0.0168), the bending area of the flexible display is It is recognized that it is bent about 90 degrees.

Even when the bending area of the flexible display is not bent normally and the bending area is twisted, strain and resistance change rates of the two bending sensors R1 and R3 occur.

14A to 14B are explanatory views when distortion occurs, and FIG. 14A is an explanatory view for explaining a flexible display device having a bending sensing device according to the second and third embodiments of the present invention, and FIG. 14B is a bending sensor. A state diagram of the bending sensor when it is embedded in a point where tensile deformation occurs and the bending region is not bent, and a state diagram when the bending sensor is embedded in a point where tensile deformation occurs and the bending region is twisted.

That is, as shown in FIG. 14A , when the bending region of the flexible display device is distorted, as shown in FIG. 14B , the length of the bending sensor R1 or R3 increases (L→L′), and the thickness and the width may be decreased (W→W′, t→t′) to increase the resistance.

As described above, when the bending region of the flexible display device is distorted, the strain and the resistance change rate of the two bending sensors R1 and R3 are calculated under the same conditions as in Equation 2, so that the strain ε is 0.5% (0.005) and the resistance change rate of the two bending sensors R1 and R3 is 0.84% (0.0084), it can be recognized that the bending area of the flexible display is bent by about 45 degrees.

As described above, when the bending region of the flexible display device does not bend normally and distortion occurs in the bending region of the flexible display device, it is impossible to determine whether the bending region is normally bent or distorted.

Accordingly, it is possible to detect that distortion occurs in the bending area of the flexible display device by arranging the bending sensor to be inclined in the bending area.

15A to 15B are explanatory diagrams for explaining changes in length and width of a bending sensor when a bending sensor is embedded in a bending area of the flexible display device to be inclined and the bending area is normally bent according to a fourth embodiment of the present invention; 15A is an explanatory diagram for explaining that the bending sensor is embedded in a bending region of the flexible display device to be inclined, and FIG. 15B is a state diagram and the bending sensor when the bending sensor is not bent when the bending sensor is embedded in the bending region to be inclined It is a state diagram when the bending area is normally bent without being twisted when the slanted is embedded in the bending area.

As shown in FIG. 15A , two bending sensors (strain gauges) are built in, respectively, in bending areas on both sides of the flexible display device, and two reference resistors, one in each non-bending area on both sides of the flexible display device, are built in. Of course, two bending sensors (strain gauges) may be embedded in a bending region of one side of the flexible display device and two reference resistors may be embedded in a non-bending region of one side of the flexible display device.

In this case, the two bending sensors (strain gauges) built into the bending area are built to be inclined, and the two reference resistors built into the non-bending area are built vertically.

In addition, one of the two bending sensors (strain gauges) built into the bending area may be built to be inclined to the left, and the other may be built to be built to be inclined to the right. In FIG. 15A, two bending sensors (strain gauges) are expressed as R1 and R3, and two reference resistances are expressed as R2 and R4.

In this way, normal bending and distortion can be distinguished by the bending sensor that is built in the bending area to be inclined.

That is, as shown in FIG. 15B , when the bending region of the soft display device is not bent, the bending sensor R1 or R3 has a length L and a width W, but since the bending sensor is built to be inclined, the length ( It is expressed as L1 = (L+W)/√2) and width (W1 = (L+W)/√2)).

When the bending region of the soft display device is bent, the bending sensor R1 or R3 has a length L′ and a width W′.

When the bending region is bent as described above, the length (L'), width (w'), and thickness (t') of the bending sensor R1 or R3 are expressed by an equation using the characteristics described in FIG. 5 . As follows.

In Equation 3 above, assuming that L=4, W=2, L'=4.0134 (0.34% increase), W'=2.0067 (0.34% increase), and resistance change ((R-R')/ R) = 0.34%.

When the bending sensor is built vertically like the reference resistors R2 and R4, the resistance change rate of the bending sensor before and after bending is about 1.68%, whereas when the bending sensor is built in an inclined way, the resistance change rate of the bending sensor is small, but the signal level that can be sensed.

Accordingly, even when the bending sensor is disposed at an angle in the bending area, the bending area of the flexible display device is not distorted, and bending can be sensed even though the bending area is normally bent.

Meanwhile, FIGS. 16A to 16B are explanatory diagrams for explaining changes in length and width of the bending sensor when the bending sensor is embedded in the bending area of the flexible display at an angle and distortion occurs in the bending area according to the fourth embodiment of the present invention As such, FIG. 16A is an explanatory diagram for explaining that the bending sensor is embedded in the bending area of the flexible display device to be inclined, and FIG. 16B is the first bending sensor when distortion occurs in the bending area in the inclined direction of the first bending sensor R1. A state diagram of the bending sensor R1 and a state diagram of the second bending sensor R3 when distortion occurs in a bending area in an inclined direction of the first bending sensor R1 is shown.

As shown in FIG. 16A , two bending sensors (strain gauges) are embedded, one in each bending area on both sides of the flexible display device, and two reference resistors, one in each non-bending area on both sides of the flexible display device, are built in. Of course, two bending sensors (strain gauges) may be embedded in a bending region of one side of the flexible display device and two reference resistors may be embedded in a non-bending region of one side of the flexible display device.

In this case, the two bending sensors (strain gauges) built into the bending area are built to be inclined, and the two reference resistors built into the non-bending area are built vertically.

Among the two bending sensors (strain gauges) built into the bending area, the first bending sensor R1 is built to be inclined in the right direction, and the second bending sensor R3 is built to be inclined in the left direction. In FIG. 16A, two bending sensors (strain gauges) are expressed as R1 and R3, and two reference resistances are expressed as R2 and R4.

In this way, normal bending and distortion can be distinguished by the bending sensor that is built in the bending area to be inclined.

That is, when distortion occurs in the bending region in the oblique direction of the first bending sensor R1, there is no change in resistance of the first bending sensor R1 as shown in FIG. 16B, and the second bending sensor R3 ), the resistance change rate is relatively large compared to the first bending sensor R1.

Therefore, when the resistance change rate of the second bending sensor R3 is relatively larger than the resistance change rate of the first bending sensor R1, the flexible display device is assumed to be twisted in the right direction (the inclined direction of the first bending sensor). may be determined, and the angle of distortion may be sensed according to a difference value between the rate of change of resistance of the first bending sensor R1 and the rate of change of resistance of the second bending sensor R3 .

Conversely, when the resistance change rate of the first bending sensor R1 is relatively larger than the resistance change rate of the second bending sensor R3, the flexible display is warped in the left direction (the inclined direction of the second bending sensor). may be determined, and the angle of distortion may be sensed according to a difference value between the rate of change of resistance of the first bending sensor R1 and the rate of change of resistance of the second bending sensor R3 .

Accordingly, as in the fourth embodiment of the present invention, the first and second bending sensors are embedded in a bending area of the flexible display to be inclined in different directions, and the resistance change rate of the first bending sensor R1 and the second By measuring the resistance change rate of the bending sensor R3, if the resistance change rate of the first bending sensor R1 and the resistance change rate of the second bending sensor R3 are similar to each other, it is determined that the bending area is normally bent, The strain ε when not bent and when bent and the resistance change rate of the two bending sensors R1 and R3 are calculated, and the bending angle of the flexible display device is measured according to the calculated values.

Conversely, by measuring the resistance change rate of the first bending sensor R1 and the resistance change rate of the second bending sensor R3, the resistance change rate of the first bending sensor R1 is the rate of change of the second bending sensor R3. If it is relatively larger than the resistance change rate, it is determined that distortion has occurred in the inclined direction of the second bending sensor, and if the resistance change rate of the second bending sensor R3 is relatively larger than the resistance change rate of the first bending sensor R1 It is determined that distortion has occurred in the inclined direction of the first bending sensor. And, according to the difference value between the resistance change rate of the first bending sensor R1 and the resistance change rate of the second bending sensor R3, the angle of distortion is sensed.

In the flexible display device having the bending sensing device according to the fourth embodiment of the present invention described above, the bending sensor is embedded in the bending area under the same conditions as the first to third embodiments of the present invention, but the bending sensor is embedded in an inclined manner. can do.

17 is a diagram illustrating a bending sensor and a reference resistance embedded in the flexible display device according to the second and third embodiments of the present invention, and FIG. 18 is a bending diagram embedded in the flexible display device according to the fourth embodiment of the present invention. The sensor and reference resistance are shown.

As described above, in the second and third embodiments of the present invention, as shown in FIG. 17 , the bending sensors R1 and R3 and the reference resistors R2 and R4 are parallel to the flexible display device (vertical). in one direction), and in the fourth embodiment of the present invention, as shown in FIG. 18 , the bending sensors R1 and R3 are inclined in the flexible display device (the first bending sensor R1 is a right rule). In the direction, the second bending sensor R3 is embedded in a left-side inclined direction), and the reference resistors R2 and R4 are embedded in a direction parallel to the flexible display device (vertical direction).

That is, the bending sensors R1 and R3 are built to be inclined in opposite directions.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and it is common in the technical field to which the present invention pertains that various substitutions, modifications and changes are possible within the scope without departing from the technical spirit of the present invention. It will be clear to those who have the knowledge of

Claims (15)

At least one bending sensor is embedded in a bending region of a film (layer) in which tensile deformation occurs and/or in a film (layer) in which shrinkage deformation occurs when a flexible display device composed of a plurality of films (layers) is bent; A flexible display device having a bending sensing device in which one or more reference resistors are built in a non-bending region of a film (layer) in which tensile deformation is generated and/or in a film (layer) in which shrinkage deformation occurs. The method of claim 1,
Flexible having a bending sensing device in which one bending sensor is built in a bending region of the film (layer) in which the shrinkage deformation occurs, and one reference resistance is built in a non-bending region of the film (layer) in which the shrinkage deformation occurs display device. The method of claim 1,
Flexible having a bending sensing device in which one bending sensor is embedded in a bending region of the film (layer) in which the tensile strain is generated, and one reference resistance is embedded in a non-bending region of the film (layer) in which the tensile strain is generated display device. 4. The method of claim 2 or 3,
The signal detected by the one bending sensor is output through a bridge circuit,
The bridge circuit includes a first connection portion in which R1 and R3 are connected in series through a first load and a second connection portion in which R2 and R4 are connected in series through a second load, between both ends of the power supply, and the first connection portion and The second connection parts are connected in parallel to each other, and an output terminal AB is provided between the first rod and the second rod,
and a bending sensing device configured to configure a selected one of R1 to R4 as the one bending sensor, and configure a resistance adjacent to the selected one as the reference resistance. 5. The method of claim 4,
wherein R1 is composed of the one bending sensor, and R2 or R3 is composed of the reference resistance,
wherein R2 is composed of the one bending sensor, and R1 or R4 is composed of the reference resistance,
wherein R3 is composed of the one bending sensor, and R1 or R2 is composed of the reference resistance,
A flexible display device having a bending sensing device, wherein R4 is the one bending sensor, and R1 or R2 is the reference resistance. The method of claim 1,
A first bending sensor is embedded in a bending region of the film (layer) in which the shrinkage deformation occurs, and a first reference resistance is embedded in a non-bending region of the film (layer) in which the shrinkage deformation occurs,
Flexible having a bending sensing device in which a second bending sensor is embedded in a bending region of the film (layer) in which the tensile strain is generated, and a second reference resistance is embedded in a non-bending region of the film (layer) in which the tensile strain is generated display device. 7. The method of claim 6,
The first and second bending sensors have a bending sensing device embedded in one side of a bending area of the flexible display device. 7. The method of claim 6,
The flexible display device having a bending sensing device, wherein the first and second bending sensors are built in one at both sides of a bending area of the flexible display device. 7. The method of claim 6,
Signals detected by the first and second bending sensors are output through a bridge circuit,
The bridge circuit includes a first connection portion in which R1 and R3 are connected in series through a first load and a second connection portion in which R2 and R4 are connected in series through a second load, between both ends of the power supply, and the first connection portion and The second connection parts are connected in parallel to each other, and an output terminal AB is provided between the first rod and the second rod,
wherein R1 and R2 are composed of the first and second bending sensors, and R3 and R4 are composed of first and second reference resistors,
wherein R1 and R3 are composed of the first and second bending sensors, and R2 and R4 are composed of first and second reference resistors,
wherein R3 and R4 are composed of the first and second bending sensors, and R1 and R2 are composed of first and second reference resistors,
wherein R2 and R4 are configured with the first and second bending sensors, and R1 and R3 are configured with first and second reference resistors. The method of claim 1,
Two bending sensors are built in the bending region of the film (layer) in which the shrinkage deformation occurs, and two reference resistors are built in the non-bending region of the film (layer) in which the shrinkage deformation occurs,
Flexible display having a bending sensing device in which two sensors are embedded in a bending region of the film (layer) in which the tensile strain is generated, and two reference resistors are embedded in a non-bending region of the film (layer) in which the tensile strain is generated Device. 11. The method of claim 10,
Signals detected by the two bending sensors are output through a bridge circuit,
The bridge circuit includes a first connection portion in which R1 and R3 are connected in series through a first load and a second connection portion in which R2 and R4 are connected in series through a second load, between both ends of the power supply, and the first connection portion and The second connection parts are connected in parallel to each other, and an output terminal AB is provided between the first rod and the second rod,
wherein R1 and R4 are composed of the two bending sensors, and R2 and R3 are composed of the two reference resistors,
A flexible display having a bending sensing device in which R2 and R3 are configured by the two bending sensors, and R1 and R4 are configured by the two reference resistors. One or more bending sensors are embedded in a bending region of the flexible display device to be inclined, and one or more reference resistances are embedded in a non-bending region of the flexible display device in a direction parallel to or perpendicular to the flexible display device. flexible display. 13. The method of claim 12,
Each of the bending sensor and the reference resistor is provided in two pieces, the first and second bending sensors are built in one side of the bending area, and the first and second reference resistors are also built in one side of the non-bending area. A flexible display device with 13. The method of claim 12,
Each of the bending sensor and the reference resistor is provided in two pieces, a first bending sensor is built in one side of the bending area and a second bending sensor is built in the other side of the bending area, and the first reference resistance is at one side of the non-bending area A flexible display device having a bending sensing device embedded therein and the second reference resistor being embedded in the other side of the non-bending region. 15. The method of claim 13 or 14,
and a bending sensing device in which the first bending sensor and the second bending sensor are built to be inclined in opposite directions.

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