KR20110126839A - Back light umit within resin layer for light-guide and lcd using the same - Google Patents

Abstract

PURPOSE: A back light unit in a resin layer for light-guide and LCD using the same are provided to realize high luminance and optical uniformity in the same light source. CONSTITUTION: A plurality of LED printing circuit board(120) is mounted to a back cover(110). A resin layer(150) diffuses and induces the light to front direction. A surface of a back cove and the LED has at least one slope area with an inclination angle. The back cover realizes the slope area by forming the back cover surface between neighboring LEDs into a wedge shape.

Description

Back light unit and liquid crystal display using the same {Back light umit within resin layer for light-guide and LCD using the same}

The present invention relates to a backlight unit capable of removing the structure of the light guide plate, modifying the structure of the back cover, reducing the structure of the backlight unit, and ensuring light efficiency, and a liquid crystal display device using the same.

A liquid crystal display (LCD) is a display device that can control a desired image by individually supplying data signals according to image information to pixels arranged in a matrix form and adjusting light transmittance of the pixels. Since it does not emit light, it is designed to display an image by installing a back-light unit on its back side.

Referring to FIG. 1A, in the backlight device 1, a flat light guide plate 30 is disposed on a substrate 20, and a plurality of side type LEDs 10 (only one) are disposed on the side of the light guide plate 30. Is placed.

The light L incident from the LED 10 to the light guide plate 30 is reflected upward by a minute reflection pattern or a reflective sheet 40 provided on the bottom surface of the light guide plate 30, and exits from the light guide plate 30. 30) the backlight is provided to the upper LCD panel 50. In the backlight unit, as shown in FIG. 1B, a plurality of optical devices, such as a diffusion sheet 31, a prism sheet 32 and 33, a protective sheet 34, and the like are disposed between the light guide plate 30 and the LCD panel 50. It can be formed into a structure for further adding a sheet.

The backlight unit serves to evenly illuminate the display image on the back of the LCD which does not emit light itself, and the light guide plate is a component that performs brightness and uniform illumination of the backlight unit. It is one of the plastic molded lenses that uniformly transmits the emitted light to the entire LCD surface. Therefore, such a light guide plate is basically used as an essential component of such a backlight unit, but because of this, the thickness of the entire product can be reduced due to the thickness of the light guide plate itself. Is causing.

The present invention has been made to solve the above problems, an object of the present invention is to implement a slim structure by removing the PSA through the LED PCB that is surface-mounted integrally to the back cover, draining the surface of the back cover, etc. It is to provide a backlight unit that can implement a high luminance and light uniformity in the same light source by implementing to have an inclined region of.

In addition, another object of the present invention is to remove the light guide plate, and to form a structure to induce a light source using a film-type resin layer, it is possible to reduce the number of light sources, to reduce the overall thickness of the backlight unit, product design To provide a backlight unit and a liquid crystal display device using the same to increase the degree of freedom.

As a means for solving the above problems, the present invention provides a backlight unit using an LED light source as a light emitting device, comprising: a plurality of LED printed circuit boards (SMT) surface-mounted on the back cover; Resin layer is formed on the back cover, the resin layer to induce the emitted light to the front; including, wherein the surface of the LED and the back cover has an inclination angle (θ) characterized in that at least one or more formed It is possible to provide a backlight unit.

In particular, the back cover may have the wedge shape of the back cover surface between adjacent LEDs to implement the inclined region.

The LED light source in the above-described structure may be formed using a side type light emitting diode (side view).

The backlight unit may further include a reflective film having a reflective pattern stacked on an inclined region of the back cover. In this case, the reflective pattern may include TiO ₂ , CaCO ₃ , BaSO ₄ , and Al ₂ O _3. It may be formed as a reflective ink containing any one of, Silicon, PS.

In addition, the above-described backlight unit may be configured to further include a diffusion plate formed on the upper surface of the resin layer, the printed optical pattern for blocking or reflecting the emitted light, in this case, the optical pattern, TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon, Light shading including a diffusion pattern formed by using a shading ink containing at least one material selected from PS, Al or a mixture of Al and TiO ₂ It may be made of an overlapping structure of the light shielding pattern using the ink.

In addition, the resin layer in the backlight unit according to the present invention may be configured to further include a bead (bead) to increase the reflection of light compared to the total resin layer 0.01 ~ 0.3%.

In addition, the backlight unit according to the present invention may further include a prism sheet or a protective sheet stacked on the diffusion plate.

In addition, as described above, a liquid crystal display device may be manufactured by applying a backlight unit according to the present invention using a side view LED as a light source and having a back cover for receiving the light source and the printed circuit board. Of course it can.

According to the present invention, a slim structure is realized by removing the PSA through the LED PCB that is integrally mounted on the back cover, and implements to have an inclined area such as a shape of draining the surface of the back cover. There is an effect that can implement a light uniformity.

In addition, the number of light sources can be reduced, the overall thickness of the backlight unit can be reduced, and the product design can be reduced by removing a light guide plate essential to the structure of a general backlight unit and forming a structure that induces a light source using a film type resin layer. It is effective to increase the degree of freedom.

In particular, by mounting the side-emitting light emitting diode in direct type, it is possible to secure the optical characteristics while greatly reducing the number of light sources, and to be applied to the structure of the flexible display by removing the light guide plate, and a reflective film including a reflective pattern in the resin layer And a diffusion plate including a light shielding pattern, thereby achieving stable light emission characteristics.

1A and 1B are conceptual views illustrating a structure of a backlight unit according to the prior art.
2 is a conceptual view illustrating main parts of a backlight unit according to the present invention.
3 shows the relationship between the inclined region and the light efficiency of the back cover according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation according to the present invention. In the description with reference to the accompanying drawings, the same components are given the same reference numerals regardless of the reference numerals, and duplicate description thereof will be omitted. The terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

The present invention removes the light guide plate from the structure of the conventional backlight unit and forms it as a resin layer to innovatively reduce the overall thickness of the backlight unit, while implementing the same to implement the inclined region such as the shape of the surface of the back cover It is an object of the present invention to provide a structure capable of reducing the number of light sources by implementing high luminance and light uniformity in a light source.

2 is a conceptual diagram illustrating a cross section of the backlight unit according to the present invention.

The backlight unit according to the present invention includes a plurality of LED printed circuit boards 120 surface-mounted on the back cover 110 and stacked on the back cover 110 to emit light. It is configured to include a resin layer 150 to induce diffusion to the front. In this case, it is preferable that the surfaces of the LED 130 and the back cover 110 have an inclined area having an inclination angle θ.

The LED light source 130 is formed on the printed circuit board 120 to emit light, in a preferred embodiment of the present invention may use a side view LED. That is, the direction of the light emitted from the LED light source 130 may not use the light source having a structure that is directed toward the side rather than going straight upward. In addition, the arrangement method is arranged in a direct type by using a side type light emitting diode, utilizing the resin layer 150 for implementing light diffusion and reflection functions, while reducing the total number of light sources and innovatively reducing the overall thickness of the backlight unit. Can be reduced.

In particular, the LED light source 130 is formed on the printed circuit board 120 as shown, the printed circuit board is preferably formed of a structure that is integrally inserted into the back cover (110). Of course, the LED light source and the printed circuit board 120 is preferably disposed a plurality.

In particular, the back cover 110 according to the present invention may be formed such that the back cover surfaces between adjacent LEDs have a wedge shape to have the inclined region. Here, the inclined region is defined as a structure in which the surfaces of the back cover are inclined at a predetermined angle between adjacent LEDs as shown in the drawing, and the inclination angle θ is shown as shown in FIG. It may be defined as θ ₁ , which is the angle between the horizontal line and the surface at the beginning of the inclination, or θ ₂ , which is the angle between the top surface of the inclined region and the vertical line at the side of the LED light source. Can be. In addition, the inclined region may have a three-dimensional shape in the entire plane, but may be embodied in a cross-sectional shape.

In addition, it is preferable that the surface of the inclined region of the back cover 110 further comprises a reflective film 140 having a reflective pattern, and the reflective pattern is TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O It may be implemented in a patterned form with a reflective ink including any one of ₃ , Silicon, PS. The reflective pattern is preferably formed in the light exit direction of the LED light source, as shown in the example, and may be arranged such that the pattern density becomes higher as the distance from the light exit direction of the LED light source increases. Such a reflection pattern, when implementing the above-described LED light source structure of the side-emitting type, can greatly reduce the number of light sources, it is possible to significantly improve the reflectance of the light.

The resin layer 150 is stacked in a structure surrounding the LED light source 130 to perform a function of dispersing light of the light source emitted laterally. That is, the resin layer 150 may perform the function of the conventional light guide plate. It is needless to say that the resin layer can be basically made of any resin capable of diffusing light. For example, the main material of the resin layer according to one embodiment of the present invention may be a resin having urethane acrylate oligomer as a main material. For example, a mixture of urethane acrylate oligomer, which is a synthetic oligomer, with a polymer type of polyacrylic can be used. Of course, it may further comprise a monomer mixed with a low-boiling-point diluent type reactive monomer such as isobornyl acrylate (IBOA), hydroxypropyl acrylate (HPA), or 2-hydroxyethyl acrylate (HPA). A photoinitiator -hydroxycyclohexyl phenyl-ketone) or an antioxidant.

In particular, the resin layer 150 may include beads to increase the diffusion and reflection of light. Preferably, the bead comprises 0.01 to 0.3% by weight of the total resin layer. That is, the light emitted from the LED in the lateral direction is diffused and reflected through the resin layer 150 and the beads so that the light can travel upward, and the reflective film 140 and the reflective pattern 141 are provided. As a result, the reflection function can be further promoted. The presence of the resin layer innovatively reduces the thickness occupied by the conventional light guide plate, thereby realizing thinning of the entire product, as well as having a soft material, and thus having a versatility applicable to a flexible display. do.

A diffusion plate 160 may be further included on the resin layer 150, and the diffusion plate 160 may serve to diffuse light emitted through the resin layer 150. In particular, the optical pattern 170 is preferably formed so that a part of the light shielding effect can be implemented in order to prevent the phenomenon that the light is excessively strong and the optical characteristics deteriorate or yellowish light is emitted. That is, the light shielding pattern may be printed using the light shielding ink so that light does not concentrate.

The optical pattern 170 is preferably formed as a light shielding pattern so that a part of the light shielding effect can be implemented in order to prevent a phenomenon in which the light is excessively strong and the optical characteristics deteriorate or yellowish light is emitted. That is, the light shielding pattern may be printed using the light shielding ink so that light does not concentrate. The optical pattern may not be a function of completely blocking light, but may be implemented to control light blocking degree or diffusing degree of light with one optical pattern to perform a function of partially blocking and diffusing light. Furthermore, more preferably, the optical pattern according to the present invention may be implemented as a superimposed printed structure of a complex pattern. The superimposed printing structure refers to a structure that forms one pattern and prints another pattern shape on the upper portion thereof.

For example, in implementing the optical pattern 170, a light shielding ink including at least one selected from TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon on the lower surface of the polymer film in the light emitting direction It can be implemented as a superimposed printing structure of the light shielding pattern using a diffusion pattern formed by using a, and a light shielding ink containing Al or a mixture of Al and TiO ₂ . That is, after forming the diffusion pattern on the surface of the polymer film by white printing, it is also possible to form a light shielding pattern thereon, or to have a double structure in the reverse order. Of course, it will be apparent that the patterned design of the pattern may be variously modified in consideration of light efficiency, intensity, and light blocking rate. Alternatively, in the sequential layer structure, a light shielding pattern, which is a metal pattern, may be formed on the middle layer, and a triple structure may be formed on the upper and lower portions thereof to implement a diffusion pattern, respectively. In such a triple structure, it is possible to select and implement the above-described materials. As a preferred example, one of the diffusion patterns is implemented using TiO ₂ having excellent refractive index, and CaCO ₃ having excellent light stability and color sense is used together with TiO _2. It is possible to realize different diffusion patterns, and to secure light efficiency and uniformity through the triple structure of the structure implementing the light shielding pattern using Al having excellent concealment. In particular, CaCO ₃ functions to subtract the exposure of yellow light to finally implement white light, thereby realizing more stable light. In addition to CaCO ₃ , particles such as BaSO ₄ , Al ₂ O ₃ , and silicon beads Larger, similarly structured inorganic materials may be used. In addition, it is preferable in view of light efficiency that the optical pattern is formed by adjusting the pattern density so that the pattern density is lowered away from the emitting direction of the LED light source.

3 illustrates the light extraction and the light efficiency when the light emitted from the LED light source 130 passes through the resin layer 150 when the surface of the back cover according to the present invention has an inclined area in a neighboring area of the light source. A comparison (see image in (d)).

(a) shows the light efficiency when the surface of the back cover is flat, (b) is a structure in which the surface of the back cover is formed to have a constant inclination, and the resin layer is also inclined, and (c) shows the surface of the back cover. The light efficiency in the case of increasing the inclination angle is shown. Comparing the results, the light extraction and light efficiency effects were significantly increased in the cases of (b) and (c), which formed the inclined region on the back cover surface and the inclined surface of the resin layer. You can check it.

The structure of the liquid crystal display device using the backlight unit will be described with reference to the drawings of FIGS. 2 and 3. That is, the backlight unit according to the present invention can be applied to the LCD through the following configuration and operation. That is, the light is emitted from the side-emitting type LED 130 in the lateral direction, and the emitted light is reflected and diffused in the resin layer 150 formed instead of the structure of the conventional light guide plate, which is particularly the reflection film 140 and The reflection pattern 141 further increases the reflection efficiency, thereby allowing the light to be guided forward. The light passing through the resin layer 150 is subjected to a process of being diffused or shielded through the optical pattern 170 formed in the diffuser plate 160, and thus the light thus purified can increase uniformity, which is added later. White light is incident on the LCD panel via an optical sheet such as a prism sheet.

In the foregoing detailed description of the present invention, specific examples have been described. However, various modifications are possible within the scope of the present invention. The technical idea of the present invention should not be limited to the embodiments of the present invention but should be determined by the equivalents of the claims and the claims.

110: back cover
120: printed circuit board
130: LED light source
140: reflective film
141: reflection pattern
150: resin layer
160: diffusion plate
161: optical pattern

Claims (10)

In the backlight unit using an LED light source as a light emitting element,
A plurality of LED printed circuit boards surface-mounted on a back cover;
And a resin layer formed on the back cover to diffuse and induce light emitted forward.
And at least one inclined region having inclined angles (θ) on the surfaces of the LED and the back cover.
The method according to claim 1,
The back cover,
And a back cover surface having a wedge shape between adjacent LEDs to implement the inclined region.
The method according to claim 1,
The LED light source is a backlight unit is formed using a side light emitting diode (side view).
The method according to claim 3,
The backlight unit,
And a reflective film having a reflective pattern stacked on the inclined region of the back cover.
The method of claim 4,
The reflective pattern is a backlight unit formed of a reflective ink containing any one of TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon, PS.
The method of claim 4,
The backlight unit,
And a diffuser plate formed on an upper surface of the resin layer and printed with an optical pattern for blocking or reflecting the emitted light.
The method of claim 6,
The optical pattern,
A diffusion pattern formed using a light shielding ink including at least one material selected from TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon, and PS;
A backlight unit comprising an overlapping structure of a light shielding pattern using a light shielding ink containing Al or a mixture of Al and TiO ₂ .
The method of claim 4,
The resin layer further comprises a bead (bead) to increase the reflection of light compared to the entire resin layer 0.01 to 0.3%.
The method of claim 6,
The backlight unit,
And a prism sheet or a protective sheet stacked on the diffusion plate.
Side view LED is used as a light source,
A liquid crystal display device comprising the backlight unit of claim 1 having a back cover for receiving the light source and the printed circuit board.

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