KR101428001B1 - Flexible liquid crystal display and manufacturing method for the same - Google Patents

Abstract

A flexible liquid crystal display comprising: a first plastic substrate; A backlight unit provided on the first plastic substrate; A second plastic substrate provided on the backlight unit; A liquid crystal layer provided on the second plastic substrate; And a third plastic substrate provided on the liquid crystal layer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a flexible liquid crystal display

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible liquid crystal display device and a manufacturing method thereof, and more particularly, to a flexible liquid crystal display device and a manufacturing method thereof, which can perform a transmissive mode through a method of forming a barrier rib for each pixel through UV irradiation without using spacers .

The LCD, which is a liquid crystal display device, displays letters and images by injecting liquid crystals between two glass plates, arranging the liquid crystals, and applying electrical pressure to change the arrangement of the liquid crystal molecules. It operates at 1.5 ~ 2V power source and low power consumption. It is used for clock, calculator, notebook computer and so on. However, there is a drawback that it does not work at low temperatures below minus 20 ° C and high temperatures above 70 ° C.

Two types of LCDs, STN and TFT, are used depending on the level of technology. STN (super twisted nematic) products are used in low-end products because their image quality is low but their price is low. Thin film transistor (TFT) products are used for professional products such as high-priced notebook computers because of their high speed and high image quality, but they are expensive. UFB (Ultra Fine & Bright) -LCD, which has both advantages of STN and TFT, is getting popular recently. UFB-LCD achieves high definition close to natural color, and has a brightness ratio more than twice that of STN, a screen brightness of 200%, and a color gamut of 38%.

Flexible LCD technology has been actively studied. Flexible LCDs can be classified into reflective mode and transmissive mode. Of these, the reflection type flexible LCD is implemented, but it is not yet implemented in the transmissive mode. Therefore, it is necessary to describe a structure of a flexible LCD in a transmissive mode and a manufacturing method for the flexible LCD.

Therefore, a problem to be solved by the present invention is to provide a liquid crystal display device having a flexible structure of a new structure and a manufacturing method thereof.

In order to solve the above problems, the present invention provides a flexible liquid crystal display device comprising: a plastic substrate; A flexible GaN backlight unit provided on the first plastic substrate; And a liquid crystal layer provided on the flexible GaN backlight unit.

According to an embodiment of the present invention, the backlight unit may include: a metal electrode laminated on the plastic substrate; And at least one or more vertical unit LED elements provided on the metal electrode, wherein the n-GaN layer, the multiple quantum well layer (MQW) and the p-GaN layer are sequentially stacked vertically.

According to an embodiment of the present invention, the at least one vertical unit LED element is commonly connected to the metal electrode.

According to an embodiment of the present invention, the flexible liquid crystal display comprises: a first plastic substrate; A flexible GaN backlight unit provided on the first plastic substrate; And a second plastic substrate provided on the backlight unit; A liquid crystal layer provided on the second plastic substrate; And a third plastic substrate provided on the liquid crystal layer.

According to an embodiment of the present invention, the flexible liquid crystal display further comprises a phosphor, a diffusion film, a polarizing film, and a wide viewing angle film which are sequentially stacked on the backlight unit, And is provided on a viewing angle film.

According to an embodiment of the present invention, the flexible liquid crystal display may further include: an electrode line patterned to correspond to the unit LED element on the second plastic substrate; A thin film transistor provided on the electrode line; A transparent conductive electrode provided on an electrode line without the thin film transistor; And an alignment film provided on the second plastic substrate and the electrode line; A liquid crystal layer provided on the alignment layer; An alignment layer provided on the liquid crystal layer; A transparent conductive electrode laminated on the alignment film; And a color filter provided on the transparent conductive electrode.

According to an embodiment of the present invention, the flexible liquid crystal display includes: a wide viewing angle film provided on the second plastic substrate; A polarizing film provided on the wide viewing angle film; And a protective film provided on the polarizing film.

According to an embodiment of the present invention, the electrode line includes chromium and the transparent conductive electrode includes ITO.

According to an embodiment of the present invention, the thin film transistor corresponds to each of the at least one or more unit LED elements.

The present invention also relates to a method of manufacturing a flexible liquid crystal display device, comprising the steps of: stacking a flexible GaN backlight unit on a first plastic substrate; Sequentially stacking a phosphor, a diffusion film, a polarizing film, and a wide viewing angle film on the backlight unit; Stacking a second plastic substrate on the wide viewing angle film; Stacking an electrode line on the second plastic substrate, a thin film transistor provided on the electrode line, and a transparent conductive electrode stacked on the electrode line; Laminating an alignment film on the transparent conductive electrode and the thin film transistor; Laminating a liquid crystal layer on the alignment layer; Stacking a transparent conductive electrode on the liquid crystal layer; Laminating a color filter on the transparent conductive electrode; Stacking a third plastic substrate on the color filter; And sequentially stacking a wide view angle film, a polarizing film and a protective film on the third plastic substrate.

According to an embodiment of the present invention, the flexible GaN backlight unit includes: a metal electrode laminated on the first plastic substrate; And at least one or more unit LED elements provided on the metal electrode, wherein the n-GaN layer, the multiple quantum well layer (MQW) and the p-GaN layer are sequentially stacked.

According to an embodiment of the present invention, the at least one unit LED element is commonly connected to the metal electrode.

According to an embodiment of the present invention, the thin film transistor corresponds to each of the at least one or more unit LED elements.

The present invention also provides a flexible liquid crystal display device manufactured by the flexible liquid crystal display device manufacturing method described above.

The present invention also provides a method of fabricating a flexible GaN backlight unit, comprising the steps of sequentially laminating a buffer layer, an n-GaN layer, a multiple quantum well layer (MQW) and a p-GaN layer on a sapphire substrate to form an element layer; Forming a plurality of unit element layers on the sapphire substrate by patterning the element layer; Depositing a metal layer on the p-GaN layer to form a p-GaN ohmic contact layer; Depositing an alloy layer for eutectic bonding on the sapphire substrate and the unit element layer; Eutectic bonding a silicon substrate coated with an alloy of the same material as the alloy layer to the alloy layer; And applying a laser to the back surface of the sapphire substrate to lift off the device layer from the sapphire substrate; Depositing a metal layer on the n-GaN layer to form an n-GaN ohmic contact layer; Bonding a thermal isolation tape to the bottom of the n-GaN ohmic contact layer; Bonding the flexible substrate to the p-GaN layer after removing the alloy layer; Applying heat to the thermal isolation tape to remove the thermal isolation tape from the n-GaN ohmic contact layer; And depositing a protective layer on the flexible substrate. The present invention also provides a method of manufacturing a flexible GaN backlight unit.

According to an embodiment of the present invention, a metal line and an anisotropic conductive film sequentially stacked on the flexible substrate are provided, and the anisotropic conductive film and the p-GaN layer are bonded.

According to an embodiment of the present invention, there is provided a method for manufacturing a backlight unit of a flexible liquid crystal display device, comprising the steps of: patterning a part of the protective layer to deposit the n-GaN ohmic contact layer and the p - exposing the GaN ohmic contact layer to the outside.

The present invention also provides a flexible GaN backlight unit manufactured by the above-described method.

As described above, in the present invention, three flexible plastic substrates are used in the form of a sandwich, a vertical GaN LED backlight unit and a liquid crystal layer are provided on each of the plastic substrates to manufacture a flexible transmissive liquid crystal display device Thus, the transmissive mode flexible liquid crystal display device is completed. Furthermore, a vertical flexible backlight unit can be effectively fabricated using a laser lift-off and an anisotropic conductive film (ACF), which can be used in a flexible liquid crystal display device.

1 to 23 are views for explaining a manufacturing method of a flexible liquid crystal display device according to an embodiment of the present invention.
24 to 42 are views illustrating a method of manufacturing an LED backlight unit according to an embodiment of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an adhesive resin and a manufacturing method thereof according to embodiments of the present invention will be described with reference to the accompanying drawings.

The following examples are intended to illustrate the present invention and should not be construed as limiting the scope of the present invention. Accordingly, equivalent inventions performing the same functions as the present invention are also within the scope of the present invention.

In addition, in adding reference numerals to the constituent elements of the drawings, it is to be noted that the same constituent elements are denoted by the same reference numerals even though they are shown in different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the constituent elements from other constituent elements, and the terms do not limit the nature, order or order of the constituent elements. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; may be "connected," "coupled," or "connected. &Quot;

1 to 23 are views for explaining a manufacturing method of a flexible liquid crystal display device according to an embodiment of the present invention.

1 is a view of a backlight unit of a flexible liquid crystal display device manufactured according to an embodiment of the present invention.

1, the backlight unit includes a first plastic substrate 100, a metal electrode 400 formed of a metal material such as Ni / Cu stacked on the plastic substrate 100, And a p-GaN layer 203, which are sequentially stacked on the n-GaN layer 201, the multiple quantum well layer (MQW) 202, and the p-GaN layer 203, And a metal electrode (400). In an embodiment of the present invention, the unit elements are spaced apart from each other by a predetermined distance, but are connected to one common metal electrode 400 in common. Further, the LED-based backlight unit according to the present invention is sealed in a polymer resin such as SU-8 to form a flat surface. The present invention is a backlight unit of a flexible liquid crystal display (LCD), and uses a flexible vertical structure LED as shown in Fig.

Referring to FIG. 2, a phosphor 500 is stacked on the backlight unit of FIG. The phosphor is irradiated with light emitted from the backlight unit of FIG. 1 and performs a function of converting the light into white.

3 to 5, a diffusion film 501, a prism sheet 502 for improving luminance, and a polarizing film 503 for adjusting the direction of light generated from the light source are sequentially formed on the phosphor film 500 Are stacked. The function of each functional film is the same as or similar to that of the functional film of the conventional liquid crystal display device, and a detailed description thereof will be omitted herein.

6 and 7, a first adhesive layer 504 is laminated on the polarizing film 503, and then, on the adhesive layer 504, light that can control the angle of light emitted from the backlight unit A viewing angle film 505 is laminated.

8 and 9, a second adhesive layer 504 is laminated on the wide viewing angle film 505, another second plastic substrate 100 is laminated on the second adhesive layer 505, .

Referring to FIG. 10, an electrode line 600 made of a metal material such as chrome is deposited on another plastic substrate 100, and then patterned.

Referring to FIG. 11, a thin film transistor (TFT) 700 is stacked on the electrode line 600. Here, the electrode layer 600 is used as a source electrode of the thin film transistor 700. Since the patterns and functions of the electrode layer, the thin film transistor, and the transparent conductive electrode 800 to be described next are in accordance with the prior art, A detailed description thereof is omitted.

Referring to FIG. 12, a transparent conductive electrode 800 such as ITO is deposited on the electrode layer 600, and then patterned. In accordance with the patterning, the thin film transistor 700 is exposed between the transparent conductive electrodes 800, and in particular, the light from the LED backlight unit is emitted to the outside through the transparent electrode 800.

13 to 15, a first alignment layer 506 is laminated on the front surface of the device, and a nematic liquid crystal 900 and a second alignment layer 506 are sequentially laminated.

Referring to FIG. 16, another transparent conductive electrode 800 is stacked on the second alignment layer 506.

17 and 18, a color filter 508 is laminated on the second alignment layer 506, and a flexible third plastic substrate 100 is provided on the color filter 508 again.

19 and 20, another wide viewing angle film 505 is laminated on the third plastic substrate 100 through the adhesive layer 504. [

21 and 22, another polarizing film 503 is laminated through another adhesive layer 504 after another adhesive layer 504 is coated with the another wide viewing angle film 505. [ Thereafter, the protective film 507 is laminated on the polarizing film 503 to complete the flexible liquid crystal display device according to the present invention (see FIG. 23).

In the present invention, three flexible plastic substrates are used in the form of a sandwich as described above, and a backlight unit and a liquid crystal layer are provided on each plastic substrate to realize a flexible transmissive liquid crystal display device.

As described above, the present invention is a backlight unit shown in Fig. Particularly, the LED backlight unit used in the embodiment of the present invention has a vertical structure, excellent in efficiency and heat dissipation characteristics, excellent in performance and service life, and can be used as a backlight unit of a liquid crystal display device in structure.

24 to 42 are views illustrating a method of manufacturing an LED backlight unit according to an embodiment of the present invention.

Referring to FIG. 24, a buffer layer (undoped GaN, 200) / n-GaN 201 / quantum well layer 202 / p-GaN layer sequentially stacked on a sapphire substrate 100 is shown. In an embodiment of the present invention, the quantum well layer 202 is made of GaN / InGaN, and the stacking of the functional layers is in accordance with the prior art, and a detailed description thereof will be omitted below.

25 and 26, the functional layer of the sapphire substrate 100 is patterned through a photolithography and an etching process. Thus, an array structure of a plurality of unit element layers aligned on the sapphire substrate 100 is completed. In one embodiment of the present invention, the photoresist 300 is a polymeric resin such as SU-8, which is removed after patterning.

Referring to FIG. 27, a metal layer 400 is stacked on a p-GaN layer 203, which is an upper layer of the unit device layer, to complete a p-GaN ohmic contact.

Referring to FIG. 28, an alloy layer 450 is deposited on the sapphire substrate and the element layer and the metal layer 400, and the alloy layer is a material capable of eutectic bonding, which proceeds in the future. In the embodiment of the present invention, In / Pd / Cr is used as the alloy layer, but the scope of the present invention is not limited thereto.

29, a silicon substrate 150 deposited with the same material layer 450 as the alloy layer 450 is brought into contact with an alloy layer 450 covering the device layer and the metal layer 400, Heat and pressure are applied to conduct the eutectic bonding. In one embodiment of the present invention, the eutectic bonding is performed at 2-3 MPa and the temperature is 200 ° C. However, the scope of the present invention is not limited thereto.

Referring to FIG. 30, the alloy layer 450 is melted by the eutectic bonding process of FIG. 29, thereby completing a form in which the silicon substrate 150 is bonded onto the alloy layer 450.

31 and 32, a laser is applied to the rear end of the sapphire substrate 100, thereby lifting off the element layer from the sapphire substrate. The laser irradiated according to the above process causes decomposition of GaN on the surface of the buffer layer 200, and the sapphire substrate 100 and the upper element layer are separated from each other due to the generated nitrogen pressure.

Referring to FIG. 33, the buffer layer 200 is plasma-etched to expose the underlying n-GaN layer 201 at the bottom.

Referring to FIG. 34, another metal layer 400 is deposited under the n-GaN layer 201 to form an n-GaN ohmic contact.

Referring to FIG. 35, a thermal separation tape 600 is bonded to the metal layer 400 forming the n-GaN ohmic contact. The thermal separation tape 600 is a tape that loses its adhesive force due to heat above a certain temperature.

Referring to FIG. 36, the alloy layer 450 is removed by a wet etching process. In the wet etching process, the alloy layer 450 is removed by immersing the alloy layer 450 in a solution for specifically removing indium (In). Alternatively, a dry etching method may be used. And the upper p-GaN ohmic contact is exposed to the outside as the alloy layer is removed.

37 and 38, devices on a thermal release tape 600 are bonded to each other using a flexible substrate 160 on which a metal line 400 is formed and an anisotropic conductive film (ACF) . At this time, a p-GaN interconnection layer 401 is formed on the side of the device region between the p-GaN contact and the flexible substrate, and the interconnection layer 401 has a path of electric signal transmission and heat dissipation do.

39 to 41, the heat separation tape is removed through the application of heat, the device is turned over, and the device is coated with a protective layer 301 having good light transmittance. Thereby, a plurality of LED unit elements of the array structure formed on the flexible plastic substrate 160 are completed. Then, the protective layer 301 is partly patterned to expose the p-GaN interconnection layer 401 and the n-GaN ohmic contacts 400 on the device to the outside.

Referring to FIG. 42, a metal layer is deposited and then patterned by a photolithography process to complete a metal line 402 formed on the ohmic contact 400. As a result, a vertical LED backlight unit for a flexible liquid crystal display device as shown in Fig. 1 or the like is completed. The LED backlight unit of the vertical type according to the present invention has a vertical structure and is capable of effectively dispersing the heat generated during the operation of the device to the side, in addition to the stable light emission through the p-GaN contact extended from the side.

It is to be understood that the terms "comprises", "comprising", or "having" as used in the foregoing description mean that the constituent element can be implanted unless specifically stated to the contrary, But should be construed as further including other elements. All terms, including technical and scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. Commonly used terms, such as predefined terms, should be interpreted to be consistent with the contextual meanings of the related art, and are not to be construed as ideal or overly formal, unless expressly defined to the contrary.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.

Claims (18)

A flexible liquid crystal display device comprising:
A first plastic substrate;
A flexible GaN backlight unit provided on the first plastic substrate; And
A liquid crystal layer provided on the flexible GaN backlight unit;
/ RTI >
The backlight unit includes:
A metal electrode laminated on the first plastic substrate; And
And at least one vertical unit LED element provided on the metal electrode and including an n-GaN layer, a multiple quantum well layer (MQW) and a p-GaN layer sequentially stacked vertically,
Wherein the at least one vertical unit LED element is commonly connected to the metal electrode. delete delete 2. The flexible liquid crystal display device according to claim 1,
A second plastic substrate provided on the backlight unit;
And a third plastic substrate provided on the liquid crystal layer,
Wherein the liquid crystal layer is provided on the second plastic substrate. 5. The flexible liquid crystal display according to claim 4,
A first polarizing film, and a first wide viewing angle film, wherein the second plastic substrate is provided on the first wide viewing angle film, A flexible liquid crystal display device. 6. The flexible liquid crystal display device according to claim 5,
An electrode line patterned to correspond to the unit LED element on the second plastic substrate;
A thin film transistor provided on the electrode line;
A first transparent conductive electrode provided on the electrode line;
A first alignment layer provided on the first transparent conductive electrode;
A second alignment layer provided on the liquid crystal layer;
A second transparent conductive electrode laminated on the second alignment layer; And
And a color filter provided on the second transparent conductive electrode,
Wherein the liquid crystal layer is provided on the first alignment layer. 7. The flexible liquid crystal display device according to claim 6,
A second wide viewing angle film provided on the third plastic substrate;
A second polarizing film provided on the second wide viewing angle film; And
And a protective film provided on the second polarizing film. Claim 8 has been abandoned due to the setting registration fee. 8. The method of claim 7,
Wherein the electrode line comprises chromium and the transparent conductive electrode comprises ITO. Claim 9 has been abandoned due to the setting registration fee. 9. The method of claim 8,
Wherein the thin film transistor corresponds to each of the at least one or more unit LED elements. The present invention relates to a method of manufacturing a flexible liquid crystal display device,
Stacking a flexible GaN backlight unit on the first plastic substrate;
Sequentially stacking a phosphor, a diffusion film, a polarizing film, and a wide viewing angle film on the backlight unit;
Stacking a second plastic substrate on the wide viewing angle film;
Laminating an electrode line on the second plastic substrate, a thin film transistor provided on the electrode line, and a laminated transparent conductive electrode patterned to expose the thin film transistor on the electrode line;
Laminating an alignment film on the transparent conductive electrode and the thin film transistor;
Laminating a liquid crystal layer on the alignment layer;
Stacking a transparent conductive electrode on the liquid crystal layer;
Laminating a color filter on the transparent conductive electrode;
Stacking a third plastic substrate on the color filter; And
And sequentially laminating a wide view angle film, a polarizing film and a protective film on the third plastic substrate. 11. The method of claim 10,
Wherein the flexible GaN backlight unit comprises: a metal electrode laminated on the first plastic substrate; And at least one unit LED element provided on the metal electrode, the unit LED element including an n-GaN layer, a multi quantum well layer (MQW), and a p-GaN layer sequentially stacked . 12. The method of claim 11,
Wherein the at least one unit LED element is commonly connected to the metal electrode. Claim 13 has been abandoned due to the set registration fee. 13. The method of claim 12,
Wherein the thin film transistor corresponds to each of the at least one or more unit LED elements. A flexible liquid crystal display device manufactured by the method for manufacturing a flexible liquid crystal display device according to any one of claims 10 to 13. A flexible GaN backlight unit manufacturing method according to claim 1,
Forming a device layer by sequentially laminating a buffer layer, an n-GaN layer, a multiple quantum well layer (MQW) and a p-GaN layer on a sapphire substrate;
Forming a plurality of unit element layers on the sapphire substrate by patterning the element layer;
Depositing a metal layer on the p-GaN layer to form a p-GaN ohmic contact layer;
Depositing an alloy layer for eutectic bonding on the sapphire substrate and the unit element layer;
Eutectic bonding a silicon substrate coated with an alloy of the same material as the alloy layer to the alloy layer; And
Applying a laser to the back surface of the sapphire substrate to lift off the device layer from the sapphire substrate;
Depositing a metal layer on the n-GaN layer to form an n-GaN ohmic contact layer;
Bonding a thermal isolation tape to the bottom of the n-GaN ohmic contact layer;
Bonding the flexible substrate to the p-GaN layer after removing the alloy layer; And
Applying heat to the thermal isolation tape to remove the thermal isolation tape from the n-GaN ohmic contact layer; And
And depositing a protective layer on the flexible substrate. ≪ RTI ID = 0.0 > 21. < / RTI > 16. The method of claim 15,
Wherein the anisotropic conductive film and the p-GaN layer are bonded to each other on the flexible substrate, wherein the metal line and the anisotropic conductive film are sequentially laminated on the flexible substrate. 17. The backlight unit manufacturing method according to claim 16,
Further comprising the step of exposing the n-GaN ohmic contact layer and the p-GaN ohmic contact layer to the outside by patterning a portion of the passivation layer after the step of depositing the passivation layer. Lt; / RTI > 18. A flexible GaN backlight unit manufactured by the method according to any one of claims 15 to 17.

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