KR20160015833A - Backlight device for LCD panel using quantum dot microcapsules - Google Patents

Abstract

The present invention relates to a backlight device for an LCD panel using quantum dot microcapsules, capable of minimizing optical loss by using a green light emitting diode (LED) as a light source and improving light quality by using quantum dot microcapsules. The backlight device for an LCD panel using quantum dot microcapsules includes: a light source generating light; a light guide plate converting a point light source generated at the light source into a surface light source by using internal total reflection; a reflecting plate reflecting the light on a lower surface of the light guide plate into the light guide plate to prevent optical loss of a rear part of the light guide plate; a quantum dot microcapsule layer located on an upper portion of the light guide plate and inducing the surface light source converted on the light guide plate to a uniform light source; a diffusion plate diffusing the surface light source outputted from the quantum dot microcapsule layer; and a prism collecting the light diffused on the diffusion plate at a certain angle and supplying the light to an LCD panel as backlight, thereby minimizing optical loss and increasing light quality and brightness.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight device for an LCD panel using a quantum dot microcapsule,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight for an LCD (Liquid Crystal Display) panel using quantum dot microcapsules. In particular, a blue LED (Light Emitting Diode) is used as a light source to minimize light loss, The present invention relates to a backlight device for an LCD panel using a quantum dot microcapsule capable of improving light quality by using a capsule.

2. Description of the Related Art Generally, a liquid crystal display (LCD) is an apparatus that converts an electrical signal into visual information by using a change in transmittance of a liquid crystal polymer according to an applied voltage.

1, the liquid crystal display comprises a backlight unit consisting of an LCD panel, a prism sheet 11, a diffusion sheet 12, a light guide plate 13, a reflection plate 14, a light source 15, And a control unit. In Fig. 1, the LCD panel, the power supply and the control unit are not shown. Among them, in the case of backlight unit (BLU), there are CCFL (Cold Cathod Fluorescent Lamp) type and LED type according to the type of light source and can be classified into direct type and side type depending on the position of light source .

In recent years, LED type has attracted attention due to low power and volume problems. In the case of LED type, direct type and side type have been released according to panel size. In the case of the side-type BLU, since the LEDs are located on both sides or one side, there is an advantage that the volume and power consumption can be reduced. On the other hand, there are disadvantages that it is difficult to increase the luminance value due to the limitation of the number of LED light sources, and uniformity is reduced when manufacturing a large-sized panel. Accordingly, a light guide plate, which is a necessary component of a liquid crystal panel using a CCFL light source, is used. In addition, the light from the point light source is uniformly dispersed along with the reflector disposed at the lower portion thereof. The light is then uniformly transmitted through the diffusion plate and the prism sheet, It plays a role.

As noted, backlight plays an essential role as a light source for a representative non-emissive LCD product family. Unlike OLED (Organic Light Emitting Diodes) and CRT type products, LCD products can not display any information on the screen when there is no light source, so backlight plays an important role in determining the quality of display products.

In the past, LCD products were mainly used as CCFL type light source, and along with the development of related technologies, slim and long life products were introduced to the market. However, due to the characteristics of CCFL, Related components are essential, and issues such as brightness, uniformity, low power and volume must be addressed in order to serve as a high quality light source.

In recent years, unlike conventional light sources, LEDs have been attracting attention in terms of low power, brightness, and volume, but the LED itself does not emit white light, but rather a combination of blue and yellow And white light is emitted by the light source. In this process, light loss occurs. In addition, since it is a point light source that is not a linear light source such as CCFL, a light guide plate, a diffusion film, and a prism sheet for switching to a planar light source are required. Therefore, there is a limitation in applying CCFL alone. .

On the other hand, since the liquid crystal panel can not emit its own light, it is necessary to irradiate flat light having uniform brightness in order to use it as an information display device.

A structure of a general LCD panel is disclosed in Fig.

The liquid crystal panel located above the backlight (BLU) can control each cell by a transistor (TFT), and can reproduce a desired color and image when a uniform amount of light is irradiated to each cell in the BLU.

In general, a BLU is divided into a direct type and a side type depending on the position of a light source. In the case of a large-sized LCD panel such as an LCD TV, a plurality of light sources are positioned below a BLU, In the case of a small-sized screen, a side-type type was preferred, but in the case of a large-sized LED TV, a side-type product is also being released. In the case of the side-type LED panel, it is divided into a flat type and a wedge type. In case of a flat type, a light source is arranged on both sides, and in case of a wedge type, a light source is disposed on only one side.

FIG. 3A shows the structure of the planar BLU, and FIG. 3B shows the structure of the side-view BLU.

In recent years, flat panel display panels (PDPs) have been becoming larger and thinner, and LEDs have been replaced with CCFLs as light sources. As shown in FIG. 4, the white LED is in a spotlight in terms of low power, brightness, and volume, unlike the conventional light source. However, the LED itself does not emit white light but applies a fluorescent material such as YAG to the blue LED And white light is emitted by a combination of blue and yellow, so that light loss occurs in this process.

However, as shown in FIG. 5, when a blue LED and a fluorescent diffuser are used, light loss is minimized in the LED itself, and light can be transmitted through the light guide plate and the reflector. Therefore, Can be produced.

On the other hand, a conventional technique for a backlight unit of a liquid crystal display device is disclosed in the following Patent Document 1: Korean Patent Laid-Open Publication No. 10-2013-0083807 (published on March 23, 2013).

The prior art disclosed in Patent Document 1 is a light guiding plate for guiding light by total internal reflection, a plurality of short wavelength light sources for emitting short wavelength light into the light guiding plate, a light guiding plate disposed on a lower surface or an upper surface of the light guiding plate, And a lenticular lens array sheet for refracting light of three colors and entering the liquid crystal subpixel, thereby forming a backlight unit. As a result, a backlight unit for directly emitting red, green, and blue light to liquid crystal subpixels and color filters respectively corresponding to red, green, and blue using a three-color light source array corresponding to three color light sources of red, Thereby improving the light transmission efficiency.

Korean Patent Laid-Open Publication No. 10-2013-0083807 (published on July 23, 2013)

However, when the LED is used as a light source, the backlight unit of the conventional liquid crystal display device does not emit white light but applies a fluorescent material such as YAG to the blue LED to emit white light by a combination of blue and yellow There is a disadvantage in that optical loss is generated in this process.

In addition, since the conventional technique requires a light guide plate, a diffusion film, a prism sheet, and the like in order to convert a point light source into a planar light source, there is a disadvantage that it is limited to be solely applied to compensate for the drawbacks of the CCFL.

It is an object of the present invention to provide a light emitting diode (LED) that minimizes light loss by using a blue LED as a light source and can improve light quality by using a quantum dot microcapsule The present invention also provides a backlight device for an LCD panel using a quantum dot microcapsule.

Another object of the present invention is to provide a backlight device for an LCD panel using a quantum dot microcapsule in which quantum dot microcapsules are applied to a backlight device to remove a diffusion plate and increase light quality and brightness.

According to an aspect of the present invention, there is provided a backlight device for an LCD panel using quantum dot microcapsules, comprising: a light source for generating light; A light guide plate for converting a point light source generated in the light source into a surface light source by total internal reflection; A reflection plate for reflecting the light from the lower surface of the light guide plate to the inside of the light guide plate to prevent light loss at the backside of the light guide plate; A quantum dot microcapsule layer disposed on the light guide plate and guiding the converted planar light source from the light guide plate to a uniform light source; And a prism that focuses the surface light source derived from the quantum dot microcapsule layer at a specific angle and supplies the light to the LCD panel as a backlight.

The light source uses a blue LED, and a light source is provided on both sides of the light guide plate.

In the light guide plate, a diffusion layer is added to the lower part of the light guide plate by a silk screen method to disperse the light to be sent to the reflection plate.

The quantum dot microcapsule layer diffuses the planar light source converted from the light guide plate by using hemispherical curvature of the surface of the film.

The quantum dot microcapsule layer is characterized in that a plurality of quantum dot microcapsules are arranged.

The quantum dot microcapsule layer is formed by coating a microcapsule-type undiluted solution having a diameter of 30 탆 with a binder in a comma coating method.

According to the present invention, light loss can be minimized by directly using a blue LED (Light Emitting Diode) as a light source, and optical quality can be improved by performing light diffusion and uniform light transmission using a quantum dot microcapsule.

Further, according to the present invention, by applying quantum dot microcapsules to a backlight device, there is an advantage that a diffusion plate can be removed and light quality and luminance can be increased.

1 is a structural view of a backlight unit using a general white LED,
2 is a structural view of a general LCD panel,
3A is a conceptual diagram of the light guide of the planar light guide plate,
FIG. 3B is a conceptual diagram of the light induction of the side light guide plate,
4 is a structural view of a conventional white LED,
5 is a structural view of a conventional blue LED,
6 is a structural view of a backlight unit for an LCD panel using a quantum dot microcapsule according to a preferred embodiment of the present invention.
7 is a process chart of a quantum dot microencapsulation process,
8 is a view showing a process for manufacturing a quantum dot microcapsule layer.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a backlight device for an LCD panel using quantum dot microcapsules according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 6 is a structural view of a backlight unit for an LCD panel using a quantum dot microcapsule according to a preferred embodiment of the present invention, and is a side-view type structure.

A backlight unit 100 for an LCD panel using a quantum dot microcapsule according to a preferred embodiment of the present invention includes a light source 101, a light guide plate 103, a reflector 104, a quantum dot microcapsule layer 105, ).

The light sources 101 and 102 function to generate light and use a blue LED and provide a light source on both sides of the light guide plate 103.

The light guide plate 103 converts the point light source generated by the light sources 101 and 102 into a surface light source by total internal reflection. The light guide plate 103 serves to disperse light sent to the reflector 104 by adding a diffusion layer in a lower portion in a silk screen manner.

The reflector 104 reflects the light of the lower surface of the light guide plate 103 to the inside of the light guide plate 103 to prevent light loss on the backlight of the light guide plate.

The quantum dot microcapsule layer 105 is positioned above the light guide plate 103 and guides the surface light source converted from the light guide plate 103 to a uniform light source. For example, the quantum dot microcapsule layer 105 serves as a substantial light emission source. The quantum dot microcapsule layer 105 preferably diffuses the surface light source converted by the light guide plate 103 using the surface curvature.

It is preferable that a plurality of quantum dot microcapsules are arranged in the quantum dot microcapsule layer 105, and it is more preferable to coat the undiluted microcapsule liquid having a diameter of 30 μm with a binder in a comma coating method.

The prism 106 focuses the planar light source diffused by the quantum dot microcapsule layer 105 at a specific angle and supplies the focused planar light source to the LCD panel (not shown) as a backlight.

The operation of the LCD panel backlight device 100 using the quantum dot microcapsule according to the preferred embodiment of the present invention will now be described in detail.

First, a quantum dot backlight structure according to a preferred embodiment of the present invention has a structure similar to a conventional structure for applying a basic production process as it is, and a blue LED is used as a light source, .

The light sources 101 and 102 using the blue LED generate light on both sides of the light guide plate 103 and project light into the light guide plate 103. [

The light guide plate (LGP) 103 is designed to meet the recent trend of minimizing the volume by using a product having a thickness within about 2 mm, and a diffusion layer is added to the lower part by a silk screen method, The light transmitted to the reflection plate 104 is more effectively dispersed. The light guide plate 103 converts a point light source generated by the light sources 101 and 102 into a surface light source by total internal reflection and outputs the surface light source. For example, the light guide plate 103 is made mostly of PMMA (Poly Methyl Methacrylate Acrylate), and a pattern is formed on the lower surface of the light guide plate 103 by a silk screen method, So that light that is scattered and directed toward the surface is directed to the LCD panel through the light guide plate.

When the light is incident on the light guide plate 103, the reflection plate 104 positioned below the light guide plate 103 reflects light generated from the light sources 101 and 102 into the light guide plate 103, Minimize losses. For example, a part of the light emitted from the light guide plate 103 is emitted to the opposite side of the panel, and light loss occurs. The reflection plate 104 having a high reflectivity is mounted on the lower end of the light guide plate 103 to re-enter the light guide plate 103 with the lost light. The reflection plate 104 mainly uses a method of coating a base material with a high reflectance, and a high reflection coating agent such as silver and TiO 2 is coated on a base material such as SUS, BRASS, Aluminum, and PET.

Next, the quantum dot microcapsule layer 105 is positioned above the light guide plate 103 and guides the surface light source converted by the light guide plate 103 to a uniform light source. For example, the quantum dot microcapsule layer 105 serves as a substantially planar light emitting source and is interposed between the light guide plate 103 and the prism 106 to induce uniform light emission, Diffusion plate) may be added. The quantum dot microcapsule layer 105 diffuses the planar light source converted by the light guide plate 103 using the curvature of the film surface. As a result, it is possible to remove the diffusing plate, which is essentially used for diffusing the light source.

Here, the quantum dot microcapsule layer 105 is prepared by arranging a plurality of quantum dot microcapsules and coating the undiluted microcapsule liquid having a diameter of 30 μm with a binder in a comma coating method.

The manufacturing process of the quantum dot microcapsules is shown in Fig.

In order to manufacture the Qdot microcapsule, the Qdot stock solution received from domestic and foreign companies is dispersed in a fat-soluble solvent having a large specific gravity, and then made into an emulsion form in an aqueous solution (Micro Emulsion) (S10). Next, a uniform microcapsule is prepared using a complex phase separation method called complex coacervation (S20). At this time, it is preferable to use a transparent polymer material to minimize difference in refractive index between the transparent base material and the transparent base film, and to prevent damage during drying and coating process by applying elastic material. The prepared microcapsules are then cured and washed (S30) to complete the QDs microcapsules (S40).

For quantum dots, it is desirable to minimize Cd exposure using the CdSe type, which has the highest efficiency and relatively good supply and demand.

Next, a quantum dot microcapsule layer is prepared by the process shown in FIG.

The quantum dot microcapsules prepared in FIG. 7 are combined with a water-soluble binder to form a coating solution (S50). At this time, the selection of the binder is a very important factor and usually acrylic type and urethane type are mainly used. Acrylic type has excellent compatibility with microcapsules, which are water-soluble polymers, but has a disadvantage in that the film surface is easily broken when the film is relatively thick with a thickness of 30 μm or more due to lack of durability and elasticity. In case of urethane binder, durability and film characteristics after final drying are very excellent, but when the pH is not controlled, a problem occurs that the composition is not formulated. Therefore, the selection of the binder is very important.

Next, a film is coated after the binder is blended (S60). Film coating is applied by using a comma coater on materials such as PET and PC, and the coating thickness is about 30 to 100 μm. When the film is thin, the luminance is lowered. When the film is too thick, the film is not dried. Therefore, it is preferable to set the film thickness in consideration of this.

Then, the coated quantum dot microcapsule layer is dried and subjected to an aging process (S70), followed by a slitting process to complete the production of the quantum dot microcapsule layer.

The light having passed through the quantum dot microcapsule layer 105 is converged at a predetermined angle through the prism 106 and is provided as a backlight to the LCD panel.

According to the present invention, since the blue LED is used as the light source as it is, the light loss can be minimized and the surface light emission can be provided through the quantum dot microcapsule to increase the light quality and brightness. . ≪ / RTI >

Although the present invention has been described in detail with reference to the above embodiments, it is needless to say that the present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

The present invention is applied to backlight technology in an apparatus for displaying information using a liquid crystal such as a liquid crystal display (LCD).

101, 102: light source
103: light guide plate
104: reflector
105: Quantum dot microcapsule layer
106: prism

Claims (6)

A light source for generating light;
A light guide plate for converting a point light source generated in the light source into a surface light source by total internal reflection;
A reflection plate for reflecting the light from the lower surface of the light guide plate to the inside of the light guide plate to prevent light loss at the backside of the light guide plate;
A quantum dot microcapsule layer disposed on the light guide plate and guiding the converted planar light source from the light guide plate to a uniform light source; And
And a prism that focuses the surface light source output from the quantum dot microcapsule layer at a specific angle and supplies the back light to the LCD panel.
The backlight unit of claim 1, wherein the light source uses a blue LED, and a light source is provided on both sides of the light guide plate.
The backlight unit of claim 1, wherein a diffusion layer is added to the lower surface of the light guide plate by a silk screen method to disperse light to be sent to the reflector.
The backlight unit of claim 1, wherein the quantum dot microcapsule layer diffuses the planar light source converted from the light guide plate using hemispherical curvature of the film surface.
The backlight unit of claim 1 or 4, wherein the quantum dot microcapsule layer has a plurality of quantum dot microcapsules arranged therein.
The quantum dot microcapsule layer as claimed in claim 1 or 4, wherein the quantum dot microcapsule layer is formed by coating a microcapsule-type raw liquid having a diameter of 30 mu m with a binder in a comma coating method. Device.

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