CN107300809B - Flexible LCD - Google Patents

Abstract

Embodiments of the present invention relate to a flexible liquid crystal display, which includes a liquid crystal layer; and a first flexible substrate and a second flexible substrate sandwiching the liquid crystal layer. The first flexible substrate has a first thickness direction phase difference value, the second flexible substrate has a second thickness direction phase difference value, and the sum of the first thickness direction phase difference value and the second thickness direction phase difference value is is 20nm to 220nm. The above-mentioned flexible liquid crystal display operates in an in-plane switching (IPS) mode or a fringe field switching (FFS) mode.

Description

Flexible LCD

technical field

Embodiments of the present invention relate to a liquid crystal display, and in particular, to a flexible liquid crystal display.

Background technique

With the widespread use of portable displays, the development of flexible displays has become more active. At present, the development of flexible displays is mainly based on flexible organic light emitting diode (OLED) displays, but the manufacturing cost thereof is relatively high.

On the other hand, due to the low cost and good moisture resistance of liquid crystal displays, flexible liquid crystal displays have also become the object of development by various manufacturers. In order to meet the requirement of "flexibility", the traditional glass substrate is generally replaced by a plastic substrate. However, whether the plastic substrate can be matched with the optical properties of the liquid crystal layer is also an important key that affects the display effect.

Therefore, how to match the optical properties of the liquid crystal and the plastic substrate to improve the overall optical performance is an important issue in the development of the flexible liquid crystal display.

SUMMARY OF THE INVENTION

An embodiment of the present invention provides a flexible liquid crystal display, including: a liquid crystal layer; and a first flexible substrate and a second flexible substrate sandwiching the liquid crystal layer. The first flexible substrate has a first thickness direction retardation value, the second flexible substrate has a second thickness direction retardation value, and the sum of the first thickness direction retardation value and the second thickness direction retardation value is 20nm to 220nm. The above-mentioned flexible liquid crystal display operates in an in-plane switching (IPS) mode or a fringe field switching (FFS) mode.

An embodiment of the present invention also provides a flexible liquid crystal display, including: a liquid crystal layer; a first flexible substrate and a second flexible substrate sandwiching the liquid crystal layer; and a first optical compensation film disposed on the first on a flexible substrate. The first flexible substrate has a first thickness direction retardation value, the second flexible substrate has a second thickness direction retardation value, the first optical compensation film has a third thickness direction retardation value, and the first thickness direction retardation value is The sum of the retardation value, the second thickness direction retardation value, and the third thickness direction retardation value is 20 nm to 220 nm. The above-mentioned flexible liquid crystal display operates in an in-plane switching (IPS) mode or a fringe field switching (FFS) mode.

An embodiment of the present invention further provides a flexible liquid crystal display, comprising: a liquid crystal layer; a first flexible substrate and a second flexible substrate sandwiching the liquid crystal layer; a first optical compensation film disposed on the first flexible substrate on the flexible substrate; and a second optical compensation film disposed on the second flexible substrate. The above-mentioned first flexible substrate has a first thickness direction retardation value, the second flexible substrate has a second thickness direction retardation value, the first optical compensation film has a third thickness direction retardation value, and the second optical compensation film has a thickness direction retardation value. There is a fourth thickness direction retardation value, and the sum of the first thickness direction retardation value, the second thickness direction retardation value, the third thickness direction retardation value and the fourth thickness direction retardation value is 20 nm to 220 nm. The above-mentioned flexible liquid crystal display operates in an in-plane switching (IPS) mode or a fringe field switching (FFS) mode.

Description of drawings

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in accordance with standard practice in the industry, the various features are not drawn to scale and are illustrative only. In fact, the dimensions of elements may be arbitrarily enlarged or reduced to clearly characterize the embodiments of the invention.

1 shows the sum of the retardation values in the thickness direction of the films disposed on one side of the liquid crystal layer and the light leakage of the IPS/FFS liquid crystal display when the retardation value (Delta_nd) of the liquid crystal layer is 350 nm according to some embodiments of the present invention relationship between quantities;

2 shows a cross-sectional view of the flexible liquid crystal display 10 according to the first embodiment of the present invention;

3 shows a cross-sectional view of the flexible liquid crystal display 20 according to the second embodiment of the present invention;

4 illustrates a cross-sectional view of the flexible liquid crystal display 30 according to the third embodiment of the present invention;

5A is a diagram illustrating the distribution of light leakage at various viewing angles of an IPS/FFS liquid crystal display using a glass substrate;

5B is a diagram illustrating the light leakage distribution at each viewing angle of an IPS/FFS liquid crystal display using a polyimide substrate according to an embodiment of the present invention;

6A is a diagram illustrating the distribution of light leakage at various viewing angles of an IPS/FFS liquid crystal display using a glass substrate;

FIG. 6B is a diagram illustrating the distribution of light leakage at various viewing angles of an IPS/FFS liquid crystal display using a polyimide substrate and an optical compensation mode according to an embodiment of the present invention.

【Symbol Description】

10, 20, 30～Flexible LCD

100～Liquid crystal layer

100'～LCD display unit

102～The first flexible substrate

104～Second flexible substrate

106～First polarizer

108～Second polarizer

200～The first optical compensation film

300～Second Optical Compensation Film

Detailed ways

A number of different implementations or examples are disclosed below for carrying out the various features of the invention, and examples of specific elements and arrangements thereof are described below to illustrate the invention. Of course, these examples are only for illustration, and should not limit the scope of the present invention. For example, it is mentioned in the specification that the first element is formed on the second element, which includes an embodiment in which the first element and the second element are in direct contact, and also includes other elements between the first element and the second element. Embodiments of the elements, ie the first element and the second element are not in direct contact. In addition, repeated reference numerals or symbols may be used in different embodiments, and these repetitions are only for the purpose of simply and clearly describing the embodiments of the present invention, and do not represent a specific relationship between the different embodiments and/or structures discussed.

In addition, where spatially relative terms such as "below", "below", "lower", "above", "higher" and similar terms may be used, these spatially relative terms are For convenience in describing the relationship between one element or feature(s) and another element or feature(s) in the figures, these spatially relative terms include different orientations of the device in use or operation, as well as the descriptions in the figures. orientation. The device may be turned in a different orientation (rotated 90 degrees or otherwise) and the spatially relative adjectives used therein are to be interpreted in the same way.

In addition, the definitions of terms related to optical properties in the embodiments of the present invention are as follows:

(1) n _x is the refractive index in the direction of the maximum in-plane refractive index of the film layer (that is, the direction of the slow axis), and _ny is the direction perpendicular to the direction of the slow axis in the film layer (that is, the direction of the advancing axis) ), n _z is the refractive index in the thickness direction of the film, and d is the thickness of the film.

(2) The film in-plane retardation value R0 is defined as (n _{x -ny} )×d. In general, the film in-plane retardation value is measured using light having a wavelength of 590 nm (nanometer).

(3) The thickness direction retardation value Rth is defined as {[(n _x + _ny )/2]-n _z }×d. In general, the thickness direction retardation value is measured using light having a wavelength of 590 nm.

Generally speaking, an In-Plane-Switching (IPS) liquid crystal display panel includes a pair of substrates and a liquid crystal layer disposed between the substrates, and the liquid crystal molecules in the liquid crystal layer are arranged parallel to the substrates. One of the substrates is a transistor array substrate and includes a plurality of pixel electrodes and common voltage electrodes, wherein the pixel electrodes and the common voltage electrodes are located on a coplanar and arranged in a cross. In addition, a fringe-field switching (FFS) liquid crystal display panel also includes a pair of substrates and a liquid crystal layer disposed between the substrates, and the liquid crystal molecules in the liquid crystal layer are arranged parallel to the substrates. Different from IPS, the pixel electrode and common voltage electrode in the transistor array substrate of FFS are not located on the same plane. Although the IPS and FFS structures are slightly different, the modes of operation are very similar. When a corresponding signal is given to the pixel electrode, the pixel electrode and the common voltage electrode form an electric field, and the liquid crystal molecules can be driven by the electric field to be horizontally twisted (parallel to the substrate) so that part of the light can pass through the liquid crystal plane. Since the liquid crystal molecules are horizontally twisted, the IPS or FFS liquid crystal display panel can obtain a better viewing angle (eg, a viewing angle of 178 degrees up and down, left and right). However, because the liquid crystal molecules of the IPS/FFS liquid crystal display panel are arranged horizontally, the transmittance of light is also poor. In order to have a better display of bright colors, it is necessary to increase the luminosity of the backlight, which leads to the problem of light leakage, which makes the contrast of the IPS/FFS LCD panel poor.

Accordingly, the present invention provides a structure for an IPS/FFS mode liquid crystal display, especially for a flexible liquid crystal display, which not only has the characteristics of good viewing angle, but also has the characteristics of low light leakage and high contrast.

Please refer to FIG. 1 , according to some embodiments of the present invention, when the retardation value (Delta_nd) of the liquid crystal layer is 350 nm, the sum of the retardation value in the thickness direction of the film layer disposed on one side of the liquid crystal layer and IPS/ The relationship between the light leakage amount of the FFS liquid crystal display. It can be clearly seen from FIG. 1 that when the sum of the retardation values in the thickness direction of the film layers disposed on one side of the liquid crystal layer is 10 nm to 110 nm (preferably 40 nm to 80 nm), the FFS/IPS display can have better performance. optical performance. In other words, if the sum of the retardation values in the thickness direction of the films disposed on one side of the liquid crystal layer can be controlled within 10 nm to 110 nm (preferably 40 nm to 80 nm), the light leakage of the FFS/IPS display can be controlled below 0.006% ( Preferably it is 0.005% or less, more preferably 0.004% or less), so the contrast ratio of the FFS/IPS display at each viewing angle can be improved.

[First Embodiment]

In this embodiment, according to the result of FIG. 1 , the phase difference between the flexible substrate and the liquid crystal layer is matched, so that the flexible liquid crystal display can have good optical performance.

Please refer to FIG. 2 , which illustrates the flexible liquid crystal display 10 of the present embodiment, which includes a liquid crystal display unit 100 ′, a first polarizer 106 and a second polarizer 108 , wherein the liquid crystal display unit 100 ′ includes a liquid crystal layer 100 , the first flexible substrate 102 and the second flexible substrate 104 . In this embodiment, the flexible liquid crystal display 10 operates in the IPS mode or the FFS mode. In other words, the liquid crystal molecules in the liquid crystal layer 100 are arranged horizontally with the first flexible substrate 102 and the second flexible substrate 104 , and the pixel electrode and the common voltage electrode (not shown in the drawings) are located on the same side of the liquid crystal layer 100 (That is, the pixel electrode and the common voltage electrode are co-located on the first flexible substrate 102 or co-located on the second flexible substrate 104).

In some embodiments, the phase difference value (Delta_nd) of the liquid crystal layer 100 may be 310 nm to 370 nm, wherein the refractive index difference Δn of the liquid crystal layer 100 may be between about 0.09 and 0.12.

Please continue to refer to FIG. 2 , the first flexible substrate 102 and the second flexible substrate 104 sandwich the liquid crystal layer 100 . In some embodiments, the first flexible substrate 102 and the second flexible substrate 104 are each in direct contact with the liquid crystal layer 100 .

For example, the first flexible substrate 102 can be an active matrix substrate, which is provided with switching elements (eg, thin film transistors) for controlling electro-optical properties of liquid crystals, and scan lines and supplies for supplying gate signals to the switching elements For the signal line of the source signal, the second flexible substrate 104 may be a color filter substrate, which is provided with a color filter. However, the above-mentioned color filters can also be disposed on the active matrix substrate.

For example, the first flexible substrate 102 and the second flexible substrate 104 may be formed of polyimide (PI), which is different from the traditional glass substrate. The substrate formed of polyimide has a high polymer structure. and process conditions, etc., it has the characteristics of optical anisotropy, thus resulting in optical retardation value. Therefore, when using it with the liquid crystal layer, it is necessary to consider the combination of the optical properties of the liquid crystal layer and the liquid crystal layer to obtain better optical performance. For example, the aforementioned substrates 102 and 104 formed of polyimide may each have appropriate optical anisotropy, eg, n _x = _ny >n _z . In addition, the visible light transmittances of the first flexible substrate 102 and the second flexible substrate 104 may each be greater than 90% (eg, 90.99% to 99.99%). In addition, the above-mentioned substrates 102 and 104 formed of polyimide have the characteristic of being flexible, so as to meet the flexibility requirement of the flexible liquid crystal display 10 . For example, a polyimide material can be coated on a substrate such as glass, and removed after film formation as the first flexible substrate 102 and the second flexible substrate 104 .

The first flexible substrate 102 has a first thickness direction retardation value R1, and the second flexible substrate 104 has a second thickness direction retardation value R2. According to the results presented in FIG. 1, the matching retardation value is 310 nm to For the liquid crystal layer 100 of 370 nm, the sum R1+R2 of the first thickness direction retardation value and the second thickness direction retardation value may be 20 nm to 220 nm, preferably 80 nm to 160 nm, so that the flexible liquid crystal display 10 has a lower high light leakage and better optical performance (eg high contrast). In some embodiments, the in-plane retardation values of the first flexible substrate 102 and the second flexible substrate 104 may each be 0 nm. In some embodiments, the thickness of at least one of the first flexible substrate 102 and the second flexible substrate 104 may be 1 μm to 25 μm, preferably 5 μm to 20 μm, so that the first thickness direction phase difference is At least one of R1 and the second thickness direction retardation value R2 is controlled to be 10 nm to 110 nm, preferably 40 nm to 80 nm. It should be noted that the first thickness direction retardation value R1 and the second thickness direction retardation value R2 may be the same or different. Thereby, the light leakage amount of the flexible liquid crystal display 10 operating in the IPS mode or the FFS mode can be controlled below 0.006% (preferably below 0.005%, more preferably below 0.004%), so that the contrast ratio at each viewing angle can be improved .

Please refer to FIG. 5A and FIG. 5B , which respectively illustrate the IPS/FFS liquid crystal display using a glass substrate and the IPS/FFS liquid crystal display using a polyimide substrate (eg, R1+R2=120 nm) in this embodiment. The amount of light leakage at each viewing angle, where block R represents the part with a larger amount of light leakage (the amount of light leakage is greater than 0.006%), and LV represents the maximum amount of light leakage in the entire area. It can be clearly seen from FIG. 5A and FIG. 5B , the sum R1+R2 of the first thickness direction retardation value R1 of the first flexible substrate 102 and the second thickness direction retardation value R2 of the second flexible substrate 104 At 120 nm, compared with the liquid crystal display of the glass substrate, the light leakage amount of each viewing angle is significantly reduced, and the maximum light leakage amount of the whole area is reduced from 0.0071% to 0.0045%.

Please continue to refer to FIG. 2 , the first polarizer 106 and the second polarizer 108 are sandwiched between the first flexible substrate 102 , the second flexible substrate 104 and the liquid crystal layer 100 . In some embodiments, the first polarizer 106 is in direct contact with the first flexible substrate 102 and the second polarizer 108 is in direct contact with the second flexible substrate 104 without any other film layers therebetween. Each of the first polarizer 106 and the second polarizer 108 may have an appropriate thickness. Each of the first polarizer 106 and the second polarizer 108 may include a hydrophilic polymer film that is uniaxially stretched after adsorbing iodine or a dichroic dye, such as polyvinyl alcohol-based film, partially dimethoxymethanated polyethylene Alcohol-based films, ethylene-vinyl acetate copolymer-based partially saponified films, combinations of the above, or other suitable materials.

To sum up the above, in this embodiment, the first flexible substrate 102 and the second flexible substrate 104 have an appropriate thickness direction retardation value (for example, the sum of the thickness direction retardation values of the two is 20 nm to 220 nm, which is relatively Preferably, it is 80 nm to 160 nm), so that it can have better optical performance when used together with the liquid crystal layer 100 with a retardation value of 310 nm to 370 nm.

[Second Embodiment]

Please refer to FIG. 3 , which illustrates the flexible liquid crystal display 20 of the present embodiment. The difference between the flexible liquid crystal display 20 and the flexible liquid crystal display 10 of the first embodiment lies in the first flexible substrate 102 of the flexible liquid crystal display 20 A first optical compensation film 200 is further disposed between the first polarizing plate 106 . In addition, the flexible liquid crystal display 20 can have good optical performance by properly matching the optical compensation film 200 , the first flexible substrate 102 , the second flexible substrate 104 and the retardation value of the liquid crystal layer.

The above-mentioned first optical compensation film 200 can have appropriate optical anisotropy, for example, n _x = _ny <n _z , and can be combined with the first substrate 102 and the second substrate 104 (whose optical anisotropy can be n _x =n ) _y >n _z ) are matched with each other to obtain an appropriate sum of the retardation values in the thickness direction, thus increasing the flexibility of the film design. In this embodiment, the first flexible substrate 102 has a first thickness direction retardation value R1, the second flexible substrate 104 has a second thickness direction retardation value R2, and the first optical compensation film 200 has a third thickness Direction phase difference value R3. For example, the third thickness direction retardation value R3 may be 0 to -500 nm. In order to match the liquid crystal layer 100 with the retardation value of 310 nm to 370 nm, the sum R1+R2+R3 of the first thickness direction retardation value R1, the second thickness direction retardation value R2 and the third thickness direction retardation value R3 may be 20 nm. to 220 nm, preferably 80 nm to 160 nm, so that the flexible liquid crystal display 20 has lower light leakage and better optical performance (eg, high contrast).

For example, at least one of the sum R1+R3 of the first thickness direction retardation value and the third thickness direction retardation value and the second thickness direction retardation value R2 is 10 nm to 110 nm, preferably 40 nm to 80 nm. It should be noted that the sum R1+R3 of the first thickness direction retardation value and the third thickness direction retardation value and the second thickness direction retardation value R2 may be the same or different. Thereby, the light leakage amount of the flexible liquid crystal display 20 operating in the IPS mode or the FFS mode can be controlled below 0.006% (preferably below 0.005%, more preferably below 0.004%), so that the contrast ratio at each viewing angle can be improved .

The thickness of the first optical compensation film 200 may be 0.1 to 50 μm, preferably 1 to 20 μm, so that the third thickness direction retardation value R3 is controlled to be 0 nm to −500 nm. For example, the first optical compensation film 200 may be formed of polyamide, polyimide, polyester, polyetherketone, polyamideimide, polyesterimide, a combination of the above, or other suitable materials. For example, the first optical compensation film 200 can be formed by a liquid crystal coating method or other suitable methods. In some embodiments where the first optical compensation film 200 is formed by a liquid crystal coating method, it can be a disc-shaped liquid crystal form.

In some embodiments, the first optical compensation film 200 may be in direct contact with the first flexible substrate 102 and/or the first polarizer 106 without other film layers interposed therebetween. In addition, although in this embodiment, the first optical compensation film 200 is a single film layer, in some other embodiments, the first optical compensation film 200 may also include multiple sublayer.

[Third Embodiment]

Please refer to FIG. 4 , which illustrates the flexible liquid crystal display 30 of the present embodiment. The difference from the flexible liquid crystal display 20 of the second embodiment lies in the second flexible substrate 104 of the flexible liquid crystal display 30 There is a second optical compensation film 300 between it and the second polarizing plate 108 . The second optical compensation film 300 may include the same or similar properties as the first optical compensation film 200 .

The above-mentioned second optical compensation film 300 can have appropriate optical anisotropy, for example, n _x = _ny <n _z , and can be matched with the first substrate 102 , the second substrate 104 and the first optical compensation film 200 to obtain an appropriate optical anisotropy. The sum of the retardation values in the thickness direction can increase the flexibility of the film design.

In this embodiment, the first flexible substrate 102 has a first thickness direction retardation value R1, the second flexible substrate 104 has a second thickness direction retardation value R2, and the first optical compensation film 200 has a third thickness The direction retardation value R3, the second optical compensation film 300 has a fourth thickness direction retardation value R4. For example, at least one of the third thickness direction retardation value R3 and the fourth thickness direction retardation value R4 may be 0 to -500 nm. In order to match the liquid crystal layer 100 with the retardation value of 310 nm to 370 nm, the sum of the first thickness direction retardation value, the second thickness direction retardation value, the third thickness direction retardation value and the fourth thickness direction retardation value R1+R2 +R3+R4 can be 20nm to 220nm, preferably 80nm to 160nm, so that the flexible liquid crystal display 30 has lower light leakage and better optical performance (eg, high contrast).

For example, at least one of the sum R1+R3 of the first thickness direction retardation value and the third thickness direction retardation value and the sum R2+R4 of the second thickness direction retardation value and the fourth thickness direction retardation value is 10 nm to 110 nm, preferably 40 to 80 nm. It should be noted that the sum R1+R3 of the first thickness direction retardation value and the third thickness direction retardation value and the sum R2+R4 of the second thickness direction retardation value and the fourth thickness direction retardation value may be the same or different. Thereby, the light leakage amount of the flexible liquid crystal display 30 operating in the IPS mode or the FFS mode can be controlled to be less than 0.006% (preferably less than 0.005%, more preferably less than 0.004%), so that the contrast ratio at each viewing angle can be improved .

Please refer to FIG. 6A and FIG. 6B , which respectively illustrate an IPS/FFS liquid crystal display using a glass substrate, and a polyimide substrate and an optical compensation film in this embodiment (for example: R1+R3=60nm, R2+R4=60nm) ) of the IPS/FFS liquid crystal display at each viewing angle, where the block R represents the larger part of the light leakage (light leakage is greater than 0.006%), and LV represents the maximum light leakage of the entire area. It can be clearly seen from FIG. 6A and FIG. 6B , the first thickness direction retardation value R1 of the first flexible substrate 102 , the second thickness direction retardation value R2 of the second flexible substrate 104 , and the optical compensation film 200 When the sum of the third thickness direction retardation value R3 and the fourth thickness direction retardation value R4 of the optical compensation film 300 is R1+R2+R3+R4 at 120nm, compared with the liquid crystal display of the glass substrate, the amount of light leakage at each viewing angle There is a significant reduction in all of them, in which the maximum light leakage of the entire area is reduced from 0.0071% to 0.0057%.

In some embodiments, the second optical compensation film 300 may be in direct contact with the second flexible substrate 104 and/or the second polarizer 108 without other film layers therebetween. In addition, although in this embodiment, the second optical compensation film 300 is a single film layer, in some other embodiments, the second optical compensation film 300 may also include multiple sublayer.

To sum up, the liquid crystal display of the embodiments of the present invention makes the flexible substrate and the optical compensation film have an appropriate thickness direction retardation value, so as to reduce the light leakage of the liquid crystal display and improve its optical performance. In addition, a flexible substrate with an appropriate thickness-direction retardation value can improve the optical performance of the liquid crystal display, and at the same time, it can also meet the requirements of flexibility.

Although the present invention has been disclosed above with several preferred embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make any modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope defined by the appended claims.

Claims (18)

1. a flexible liquid crystal display, is characterized in that, comprises: a liquid crystal layer; and a first flexible substrate and a second flexible substrate sandwiching the liquid crystal layer; Wherein the first flexible substrate has a first thickness direction retardation value, the second flexible substrate has a second thickness direction retardation value, and the first thickness direction retardation value and the second thickness direction retardation value The sum of the phase difference values is 20nm to 220nm; Wherein the flexible liquid crystal display operates in a lateral electric field switching mode or a boundary electric field switching mode; And wherein the optical anisotropy of the first flexible substrate and the second flexible substrate is respectively n _x = _ny >n _z , wherein n _x is the refractive index in the direction with the largest in-plane refractive index, n _y is the refractive index in the direction perpendicular to the direction in which the in-plane refractive index is the largest, and n _z is the refractive index in the thickness direction of the film. 2 . The flexible liquid crystal display of claim 1 , wherein at least one of the first thickness direction retardation value and the second thickness direction retardation value is 10 nm to 110 nm. 3 . 3 . The flexible liquid crystal display of claim 1 , wherein the sum of the first thickness direction retardation value and the second thickness direction retardation value is 80 nm to 160 nm. 4 . 4 . The flexible liquid crystal display of claim 3 , wherein at least one of the first thickness direction retardation value and the second thickness direction retardation value is 40 nm to 80 nm. 5 . 5. A flexible liquid crystal display, characterized in that, comprising: a liquid crystal layer; a first flexible substrate and a second flexible substrate sandwiching the liquid crystal layer; and a first optical compensation film disposed on the first flexible substrate; The first flexible substrate has a first thickness direction retardation value, the second flexible substrate has a second thickness direction retardation value, and the first optical compensation film has a third thickness direction retardation value , and the sum of the first thickness direction retardation value, the second thickness direction retardation value and the third thickness direction retardation value is 20 nm to 220 nm; Wherein the flexible liquid crystal display operates in a lateral electric field switching mode or a boundary electric field switching mode; And wherein the amount of light leakage of the flexible liquid crystal display is 0.006% or less. 6 . The flexible liquid crystal display of claim 5 , wherein the sum of the first thickness direction retardation value and the third thickness direction retardation value and the second thickness direction retardation value are at least one of 6 . which is 10nm to 110nm. 7 . The flexible liquid crystal display of claim 5 , wherein the sum of the first thickness direction retardation value, the second thickness direction retardation value and the third thickness direction retardation value is 80 nm to 70 . 160nm. 8 . The flexible liquid crystal display of claim 7 , wherein the sum of the first thickness direction retardation value and the third thickness direction retardation value and the second thickness direction retardation value are at least one of: 8 . Which is 40nm to 80nm. 9 . The flexible liquid crystal display of claim 5 , wherein the third thickness direction retardation value is 0 nm to −500 nm. 10 . 10. A flexible liquid crystal display, comprising: a liquid crystal layer; a first flexible substrate and a second flexible substrate sandwiching the liquid crystal layer; a first optical compensation film disposed on the first flexible substrate; and a second optical compensation film disposed on the second flexible substrate; The first flexible substrate has a first thickness direction retardation value, the second flexible substrate has a second thickness direction retardation value, and the first optical compensation film has a third thickness direction retardation value , the second optical compensation film has a fourth thickness direction retardation value, and the first thickness direction retardation value, the second thickness direction retardation value, the third thickness direction retardation value and the fourth thickness direction retardation value The sum of the phase difference values is 20nm to 220nm; Wherein the flexible liquid crystal display operates in a lateral electric field switching mode or a boundary electric field switching mode; And wherein the amount of light leakage of the flexible liquid crystal display is 0.006% or less. 11. The flexible liquid crystal display of claim 10, wherein the sum of the first thickness direction retardation value and the third thickness direction retardation value, the second thickness direction retardation value and the third thickness direction retardation value At least one of the sum of the four thickness-direction retardation values is 10 nm to 110 nm. 12 . The flexible liquid crystal display of claim 10 , wherein the first thickness direction retardation value, the second thickness direction retardation value, the third thickness direction retardation value and the fourth thickness direction difference value are 12 . The sum of the directional retardation values is 80 nm to 160 nm. 13 . The flexible liquid crystal display of claim 12 , wherein the sum of the first thickness direction retardation value and the third thickness direction retardation value and the second thickness direction retardation value are equal to the At least one of the sum of the fourth thickness direction retardation values is 40 nm to 80 nm. 14 . The flexible liquid crystal display of claim 10 , wherein at least one of the third thickness direction retardation value and the fourth thickness direction retardation value is 0 nm to −500 nm. 15 . 15. The flexible liquid crystal display of claim 1, 5 or 10, wherein the first flexible substrate and the second flexible substrate comprise polyimide, and/or the first flexible substrate The thickness of at least one of the flexible substrate and the second flexible substrate is between 1 μm and 25 μm. 16. The flexible liquid crystal display of claim 1, 5 or 10, further comprising a first polarizer and a second polarizer, respectively disposed on the first flexible substrate and the first polarizer on two flexible substrates. 17. The flexible liquid crystal display of claim 1, 5 or 10, wherein the first flexible substrate has a first film in-plane retardation value and the second flexible substrate has a The second film in-plane retardation value, wherein the first film in-plane retardation value and the second film in-plane retardation value are respectively 0 nm. 18. The flexible liquid crystal display according to claim 5 or 10, wherein the optical anisotropy of the first flexible substrate and the second flexible substrate is n _x = _ny >n respectively _z , where n _x is the refractive index in the direction of the maximum in-plane refractive index, _ny is the refractive index in the direction perpendicular to the direction of the maximum in-plane refractive index, and n _z is the refractive index in the thickness direction of the film.

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