KR101269952B1 - Back light unit within resin layer for light-guide and LCD using the same - Google Patents

Abstract

The present invention relates to a backlight unit, and in particular, a plurality of LED light sources formed on a printed circuit board on which a reflective film is stacked, and a resin layer laminated on the LED light sources to diffuse and radiate the emitted light to the front; And a diffuser plate on which an optical pattern for blocking or reflecting light transmitted through the resin layer is printed, further comprising a surface treatment layer formed in a structure accommodating the optical pattern.
According to the present invention, the number of light sources can be reduced, and the overall thickness of the backlight unit can be reduced by removing a light guide plate essential to the structure of a general backlight unit and forming a structure for inducing a light source using a film type resin layer. This has the effect of increasing the degree of freedom in product design.
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 ensuring stable light emitting characteristics.

Description

Back light unit within resin layer for light-guide and LCD using the same}

The present invention relates to a backlight unit capable of thinning the structure of a backlight unit by removing the structure of the light guide plate and securing a 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.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to remove the light guide plate essential to the structure of a general backlight unit and to form a structure for inducing a light source using a film-type resin layer, The present invention provides a backlight unit and a liquid crystal display device using the same, which can reduce the cost, reduce the overall thickness of the backlight unit, and increase the degree of freedom of product design.

As a means for solving the above problems, the present invention is a backlight unit using an LED light source as a light emitting device, a plurality of LED light sources formed on a printed circuit board; and the light emitted by being stacked on the LED light source It is possible to provide a backlight unit comprising a; a resin layer to induce a diffusion forward.

In particular, the LED light source used in the backlight unit according to the present invention described above may be formed using a side view light emitting diode (side view).

In addition, the backlight unit according to the present invention may further include a reflective film having a reflective pattern stacked on an upper surface of the printed circuit board.

The backlight unit may further include a diffusion plate formed on an upper surface of the resin layer and printed with an optical pattern for blocking or reflecting the emitted light.

The resin layer according to the present invention may further comprise a bead (bead) to increase the reflection of light compared to the total resin layer 0.01 ~ 0.3%.

In addition, the optical pattern formed on the diffusion plate of the backlight unit according to the present invention, is formed on the lower surface of the diffusion plate, it may be formed on the vertical upper surface or the light emission direction surface of the LED light source. In this case, the optical pattern, the diffusion pattern is formed using a light shielding ink containing any one or more materials selected from TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon, Al or Al and TiO ₂ It may be made of a superposition structure of the light shielding pattern using a light shielding ink containing a mixture of.

In this case, the optical pattern may have a structure in which a diffusion pattern is printed on the light blocking pattern or a structure in which the diffusion pattern is printed on and under the light blocking pattern.

In addition, the optical pattern according to the present invention, the pattern density is lower the farther away from the emitting direction of the LED light source, the reflective pattern, the farther away from the light emitting direction of the LED light source can be arranged so as to increase the pattern density. .

In this case, the reflective pattern may be formed by applying a reflective ink including any one of TiO ₂ and Al ₂ O ₃ .

The backlight unit may further include a prism sheet or a protective sheet stacked on the diffusion plate.

The backlight unit having the above-described structure according to the present invention uses a side view LED as a light source and includes the above-described structure having a resin layer stacked in a structure for receiving the light source. Of course, it can be applied.

According to the present invention, the number of light sources can be reduced, and the overall thickness of the backlight unit can be reduced by removing a light guide plate essential to the structure of a general backlight unit and forming a structure for inducing a light source using a film type resin layer. This has the effect of increasing the degree of freedom in product design.

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 ensuring stable light emitting characteristics.

1A and 1B are conceptual views illustrating a structure of a backlight unit according to the prior art.
2A is a conceptual view illustrating main parts of a backlight unit according to the present invention.
2B is a functional state diagram illustrating the functions of the resin layer and the surface treatment layer of the backlight unit according to the present invention.
Figure 2c is a plan view showing the arrangement of the optical pattern of the LED and the diffusion plate according to the present invention.
2d is an exemplary view showing an optical pattern according to the present invention.
2E is an exemplary view showing a reflection pattern according to the present invention.
3 is a view showing an operating state of the backlight unit 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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description with reference to the accompanying drawings, the same reference numerals denote the same elements regardless of the reference numerals, and redundant 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 provides a structure in which the light guide plate is removed from the structure of a conventional backlight unit, and formed into a resin layer, thereby innovatively reducing the overall thickness of the backlight unit and reducing the number of light sources, while providing a diffuser plate and a resin layer. Summary of the Invention It is an object of the present invention to provide a backlight unit having a surface treatment layer capable of removing an air layer generated at a step of an optical pattern generated at the time of coupling.

2A to 2B, this is a conceptual view showing the main part of the structure of the backlight unit according to the present invention, and FIG. 2B is a conceptual view showing the functions of the resin layer and the surface treatment layer.

The backlight unit according to the present invention includes a plurality of LED light sources 111 formed on the printed circuit board 110 and a resin layer 140 stacked on the LED light sources 111 to diffuse and radiate the emitted light to the front. It may be configured to include). Of course, in this case, the reflective film 120 may be stacked on the upper surface of the printed circuit board, and the diffusion plate 150 may be provided on the resin layer 140, and the prism sheet 160 may be disposed thereon. ), The protective sheet 170 may be additionally provided.

In particular, in the above-described structure, the present invention is a surface treatment layer that can planarize the pattern irregularities of the optical pattern between the resin layer 140 and the optical pattern 151 formed on the surface of the diffusion plate 150 ( It is desirable to further have 152).

The surface treatment layer 152 excludes a difference between a dark portion and a curved portion caused by the formation of an air layer due to a step generated during adhesion between the optical pattern 151 of the diffusion plate and the resin layer 140 disposed below the diffuser plate. In order to do so, it is preferable that the planarization layer is implemented as a structure covering the level of the entire optical pattern 151. Therefore, as shown, the surface treatment layer is preferably formed to be equal to or greater than the height of the optical pattern.

In addition, the surface treatment layer 152 is more preferably to improve the adhesion using the same material as the resin layer 140 basically.

As shown, the LED light source 111 is arranged on at least one or more numbers on the printed circuit board 110 to emit light, in a preferred embodiment of the present invention is to use a side view LED (side view LED) Can be. That is, the direction of the light emitted from the LED light source 111 does not go straight to the top, but may use a light source having a structure that exits toward the side. In addition, the layout method is arranged in a direct type by using a side type light emitting diode, and by utilizing a resin layer that implements light diffusion and reflection functions, the total thickness of the backlight unit can be innovatively reduced while reducing the total number of light sources. Will be.

The resin layer 140 is stacked in a structure surrounding the LED light source 111 to perform a function of dispersing light of the light source emitted laterally. That is, the resin layer 140 may perform a 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 this case, as shown in FIG. 2B, the resin layer 140 may include beads 141 to increase light diffusion and reflection. Preferably, the bead comprises 0.01 to 0.3% by weight of the total resin layer. That is, the light emitted laterally from the LED is diffused and reflected through the resin layer 140 and the bead 141 to proceed upwards, and the reflective film 120 and the reflective pattern 121 to be described later When provided, this 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.

The reflective film 120 is more preferably provided with a reflective pattern 121 through the white (whitr) printing to have a reflective material so as to disperse the light emitted from the light source and to promote the dispersion of light. The reflective pattern may be printed by using a reflective ink including any one of TiO ₂ and Al ₂ O ₃ .

The diffusion plate 150 serves to diffuse the light exiting through the resin layer 140, and in particular, the light is excessively strong to prevent the optical property from deteriorating or yellowish light. In order to achieve a predetermined light shielding effect, the optical pattern 151 is preferably formed. That is, the light shielding pattern may be printed using the light shielding ink so that light does not concentrate. In addition, the surface treatment layer 152 is formed on the optical pattern 151 formed under the diffusion plate to eliminate the dark portion due to the air layer generated during printing of the optical pattern as described above. To improve the adhesion between the 150 and the resin layer 140. In particular, for this purpose, the surface treatment layer 152 may be formed of the same material as that of the resin layer, as described above.

Referring to FIG. 2C, this is a conceptual diagram illustrating a structure in which the diffusion plate 150 is covered on the LED light source 111, and in particular, illustrates a positional relationship with the optical pattern 151. The optical pattern 151 may be implemented in a manner that is basically printed on the lower surface or the upper surface of the diffuser plate 150, particularly preferably at the position of the LED light source 111 disposed below the diffuser plate It is preferable to arrange | position in the direction in which light exits (pre-direction). That is, it may be disposed on the diffuser plate at a position corresponding to the vertical upper surface or the light exit direction surface of the LED light source.

2D is a plan view conceptually illustrating an example of implementing such an optical pattern.

The LED light source 111 is disposed below the diffusion plate 150, and the optical pattern 151 is formed on the bottom surface of the diffusion plate toward the light emission direction. 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 151, a light shielding ink including any one or more materials selected from TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and Silicon on a lower surface of the diffusion plate in the light emitting direction It is possible to implement a superimposed printed structure of the diffusion pattern 151a formed by using and the light shielding pattern 151b using a light shielding ink including Al or a mixture of Al and TiO ₂ . In other words, after the diffusion pattern 151a is formed by white printing on the surface of the diffusion plate, the light shielding pattern 151b may be formed thereon or may be formed in a double structure in the reverse order. Of course, it will be obvious that the formation design of such a pattern can be variously modified in consideration of light efficiency, intensity, and shading ratio.

Alternatively, the light blocking pattern 151b, which is a metal pattern, may be formed in the middle layer in the sequential layer structure, and may be formed in a triple structure that implements the diffusion pattern 151a on the upper and lower portions thereof. In such a triple structure, it is possible to select and implement the above-mentioned materials. As a preferable example, one of the diffusion patterns is realized by using TiO ₂ having excellent refractive index, and CaCO ₃ excellent in light stability and color is used together with TiO ₂ The light diffusing pattern can be realized and the light efficiency and homogeneity can be ensured through the triple structure which realizes a light shielding pattern by using Al which is excellent in 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.

Figure 2e is a plan view showing the structure of a reflective film and a reflective pattern according to the present invention.

That is, the reflective film 120 according to the present invention is stacked on the printed circuit board, and the LED light source 111 protrudes to the outside through the holes formed on the reflective film. When the LED light source is implemented in a side-emitting type structure, the number of light sources can be greatly reduced as described above, and the reflection pattern 130 is implemented to greatly improve the reflectance of light in order to reduce the reduction rate. desirable.

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. That is, by increasing the pattern density of the second region 132 far from the emission direction than the first region 131 close to the emission direction, the reflectance can be increased. Of course, the structure of the pattern can be implemented in various shapes according to the design intention. In addition, the reflective pattern may be formed by printing using a reflective ink including any one of TiO ₂ and Al ₂ O ₃ .

3 is an operating state diagram showing an operating state of the structure of the backlight unit according to the present invention described above.

As shown in the drawing, the backlight unit according to the present invention emits light laterally from the side-emitting LED 111, and the emitted light is reflected and diffused from the resin layer 140 formed instead of the structure of the conventional light guide plate. In particular, the reflection film 120 and the reflection pattern 130 by the reflection efficiency is further increased, it is possible to guide the light forward. The light passing through the resin layer 140 is subjected to a process of being diffused or shielded through the optical pattern 151 formed on the diffusion plate 150, and the light L thus purified is optical such as the prism sheet 160. White light enters the LCD panel through the sheet. In particular, the optical pattern 151 is provided with a surface treatment layer 152 to improve the adhesion to the resin layer 140, and to remove the formation of the air layer during adhesion to improve the generation and reliability of the dark portion This is more preferable.

As described above, the backlight unit according to the present invention removes the structure of the light guide plate, applies a side light-emitting LED as a light source, diffuses light through the resin layer, and induces light through reflection, thereby reducing the thickness and the number of light sources. On the other hand, the luminance reduction and uniformity problems caused by the reduction of the light source can be compensated for by the optical patterns such as the reflection pattern, the light shielding pattern, and the diffusion pattern, thereby realizing the uniformity of the image quality. In addition, a reliable backlight unit may be provided by further including a surface treatment layer in order to remove the adhesive force that may occur due to the step of the optical pattern when the resin layer and the diffusion plate are adhered, and to generate dark areas due to the formation of the air layer. It can be applied to a liquid crystal display device having the same.

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: printed circuit board
111: LED light source
120: reflective film
130: reflection pattern
140: Resin layer
150: diffusion plate
151: optical pattern
151a: diffusion pattern
151b: shading pattern
152: surface treatment layer
160: prism sheet

Claims (9)

A plurality of LED light sources formed on the printed circuit board; and
A resin layer in close contact with the LED light source and stacked on the printed circuit board in a structure in which the LED light source is buried, and inducing diffused light forward;
A diffusion plate on which an optical pattern for shielding or reflecting light transmitted through the resin layer is printed;
And a surface treatment layer formed between the resin layer and the diffuser plate to accommodate the optical pattern.
The optical pattern is a diffusion pattern formed by using a light shielding ink containing at least one material selected from TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and silicon, or by mixing TiO ₂ with Al or Al. A light shielding pattern formed of a light shielding ink including a material,
The resin layer includes a mixture of a urethane acrylate oligomer, a polyacryl polymer type, and any one monomer selected from IBOA (isobornyl acrylate), HPA (Hydroxypropyl Acrylate) and 2-HEA (2-Hydroxyethyl Acrylate). Backlight unit.
The method according to claim 1,
The surface treatment layer is a backlight unit, characterized in that formed in the same or greater than the height of the optical pattern.
The method according to claim 1,
And the surface treatment layer is formed of the same material as the resin layer.
The method according to claim 1,
The backlight unit includes:
And a reflective film having a reflective pattern stacked on an upper surface of the printed circuit board.
The method according to claim 1,
The optical pattern is formed on the surface of the diffusion plate,
Or a diffusion pattern implemented with at least one layer, or
Or a light blocking pattern for shielding light from the diffusion pattern.
The method according to claim 1,
The resin layer,
The backlight unit further comprises a bead (bead) to increase the reflection of light relative to the total resin layer weight 0.01 ~ 0.3%.
delete The method of claim 4,
The reflective film has at least one reflective pattern
The reflective pattern is a backlight unit, characterized in that formed using a reflective ink containing TiO ₂ or Al ₂ O ₃ .
A liquid crystal display device comprising the backlight unit of claim 1.

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