KR101148102B1 - Back light umit within resin layer for light-guide and LCD using the same - Google Patents

Abstract

The present invention relates to a backlight unit, comprising: a plurality of LED light sources formed on a printed circuit board on which reflective films are stacked; and a resin layer laminated on the LED light sources to diffuse and radiate the emitted light to the front; And a diffusion plate on which an optical pattern for shielding light emitted from the LED light source is printed. In particular, the diffusion pattern includes at least one layer of the optical pattern, or the diffusion pattern layer. The light shielding pattern for shielding light is formed in a combined structure.
According to the present invention, an optical pattern capable of shielding or diffusing light on the surface of the diffuser plate of the backlight unit is realized, and further, the uniformity of light and the blocking of yellow light are realized by the combination of the diffusion pattern and the metal pattern. There is an effect to derive the light quality.

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 having a diffuser plate having a pattern for removing a structure of a light guide plate and increasing a light blocking and haze effect.

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.

In addition, the diffusion plate or diffusion sheet 31 used to diffuse light in the conventional backlight unit forms a light shielding pattern to prevent light concentration, and the light shielding pattern implements light shielding effect using Ag. . However, the optical pattern using Ag, which realizes such a shading effect, has a disadvantage that it is difficult to secure the uniformity of the overall light due to the complete shading on the pattern portion. Finally, white light is finally generated by the derivation of yellow light generated from the LED light source itself. This results in lowering the reliability of the backlight unit.

The present invention has been made to solve the above-described problems, an object of the present invention is to implement an optical pattern that can shield or diffuse the light on the surface of the diffuser plate of the backlight unit, further by combining a diffusion pattern and a metal pattern It is to provide a backlight unit that can obtain a uniform light quality by ensuring the uniformity of light and blocking the yellow light.

In addition, another object of the present invention is to remove the light guide plate necessary for the structure of the general backlight unit, and to form a structure to guide the light source using a film-type resin layer, it is possible to reduce the number of light sources, It is to provide a backlight unit that can reduce the thickness and increase the degree of freedom of product design.

As a means for solving the above problems, the present invention is a plurality of LED light source formed on a printed circuit board on which a reflective film is laminated; and a resin layer laminated on the LED light source, to diffuse the light emitted forward ; It is possible to provide a backlight unit including a; diffusion plate printed with an optical pattern for shielding the light emitted from the LED light source.

The optical pattern may be formed on a surface of the diffusion plate, and may include a diffusion pattern formed of at least one layer, or a combination of a light shielding pattern that shields light from the diffusion pattern layer.

In particular, the optical pattern is a first pattern which is a diffusion pattern formed using a light shielding ink including any one or more materials selected from TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and silicon, or a mixture of two or more thereof. Can be formed.

Alternatively, the optical pattern may be formed of a first pattern, which is a diffusion pattern for diffusing light, and a second pattern, which is a light shielding pattern formed on or under the first pattern.

In addition, the optical pattern may include a second pattern which is a light shielding pattern printed on the upper or lower portion of the first pattern, which is a diffusion pattern for partially diffusing or shielding the emitted light, and printed to block or reflect the emitted light, and the first and The structure may further include a third pattern which is a diffusion pattern formed to cover the second pattern.

In the structure of the above-mentioned pattern, TiO ₂ or TiO ₂ And it may be made of a material containing CaCo ₃ , the light-shielding ink containing a mixture of TiO ₂ to Al or Al, the third pattern is TiO ₂ or TiO ₂ And CaCo ₃ .

Particularly, in this case, the first pattern or the second pattern may be formed in a structure further including a bead for shielding and diffusing outgoing light. The first to third patterns may have a thickness of 4 to 100 μm. Can be.

The reflective film constituting the backlight unit according to the present invention may be formed in a structure in which at least one reflective pattern is printed, the reflective pattern using a reflective ink containing any one of TiO ₂ , Al ₂ O ₃ . Can be formed.

In addition, the inside of the resin layer according to the present invention may further comprise a bead (Bead) to reflect or diffuse light.

According to the present invention, an optical pattern capable of shielding or diffusing light on the surface of the diffuser plate of the backlight unit is realized, and further, the uniformity of light and the blocking of yellow light are realized by the combination of the diffusion pattern and the metal pattern. There is an effect to derive the light quality.

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

In addition, by mounting the side-emitting light emitting diode in a direct type, it is possible to secure the optical characteristics while significantly reducing the number of light sources, and can 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.
2 is a conceptual view illustrating main parts of a backlight unit according to the present invention.
3 is a plan view showing the arrangement of the optical pattern of the LED and the diffusion plate according to the present invention.
4 is a view showing an example of manufacturing an optical pattern according to the present invention.
5 is an exemplary view showing a reflection pattern according to the present invention.
6 is a view showing the structure and 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. 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 can increase the efficiency of light by forming a diffuser plate having an optical pattern layer that can effectively block and diffuse light in the backlight unit, remove the light guide plate from the structure of the conventional backlight unit, and form it as a resin layer Therefore, it is an object of the present invention to provide a structure that can reduce the total thickness of the backlight unit while reducing the number of light sources.

Referring to FIG. 2, which illustrates the structure of a backlight unit according to the present invention, the backlight unit according to the present invention includes a plurality of LED light sources 111 formed on the printed circuit board 110 and the LED light sources ( The resin layer 140 may be stacked on the 111 to include a resin layer 140 that induces the emitted light to diffuse forward. 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, the diffusion plate 150 in the above-described structure performs a function of diffusing the light emitted through the resin layer 140, in particular, the light is excessively strong so that the optical characteristics deteriorate or yellow light is derived In order to prevent the phenomenon of being yellowish, it is preferable that the optical pattern 151 is formed so that a part of the shading effect can be realized. That is, the light shielding pattern may be printed using the light shielding ink so that light does not concentrate.

The optical pattern according to the present invention is a diffusion pattern formed using a light shielding ink containing any one or more selected from among TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon on the lower surface of the diffusion plate in the direction of light emission And a light shielding pattern using a light shielding ink including Al or a mixture of Al and TiO ₂ may be formed in a printed structure by overlapping a single layer or a composite layer.

3 shows an exemplary view of forming an optical pattern according to the present invention.

Referring to the embodiment of the optical pattern with reference to this, in the implementation of the optical pattern 151, in the light emitting direction of the diffusion plate selected from TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon The diffusion pattern 151a formed by using the shading ink containing at least one material and the shading pattern 151b using the shading ink including Al or a mixture of Al and TiO ₂ may be implemented. have. 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 apparent that the patterned design of the pattern may be variously modified in consideration of light efficiency, intensity, and light blocking rate.

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-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.

A process of forming the optical pattern will be described with reference to FIG. 4.

Referring to the embodiment through the drawings, the optical pattern according to the invention can be formed in a structure that is printed on the upper or lower surface of the diffusion plate 150, (a) one pattern layer (first pattern; 151a) to implement first degree printing, or (b) to superimpose the second pattern 151b on the first pattern, or (c) after printing the first and second patterns, the upper part thereof. The third pattern can be formed in a triple layer structure to be overprinted. The superimposed printing structure refers to a structure that forms one pattern and prints another pattern shape on the upper portion thereof.

As shown in (a), when the optical pattern is implemented on the surface of the diffusion plate 150 by 1 degree printing, printing is performed by using a light shielding ink containing TiO 2 basically, thereby implementing an effective light shielding effect. At the same time, it is desirable to implement a diffusion effect. In this case, the light-shielding ink may be embodied by adding a inorganic pigment such as TiO ₂ to a hydrocarbon-based or ester-based solvent to a resin such as an acrylic polyol, for example, in particular a silicone type It may be formed by further comprising an additive (additive) such as a wetting and dispersing agent or a leveling agent.

In addition, it is possible to use any one or more materials selected from CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and Silicon for TiO ₂ or TiO ₂ .

In this case, in the case of the inorganic pigment, those having a particle size of 500 to 550 nm can be used. As one test example, a mixture of 20 to 25% of an acrylic polyol resin, 20 to 29% of a solvent, 50 to 55% of an inorganic pigment, and 1 to 2% of an additive may be used relative to the weight of the total shading ink.

(b) Next, another optical pattern according to the present invention has a double structure in which a diffusion pattern (first pattern) implementing a diffusion or shading effect and a light shielding pattern (second pattern) implementing a shading effect are superimposed. It can be formed to implement. That is, after printing the first pattern described in the above (a), it can be formed in a structure for printing the second pattern through the light-shielding ink using a metal-based material on the upper portion. The second pattern may be printed using a light shielding ink including Al or a material in which TiO ₂ is mixed with Al. Of course, in this case, the stacking order of the first pattern and the second pattern may be different.

The second pattern is characterized in that it comprises a metal-based pigment, for example, a light-shielding ink constituting the same, such as resins such as acrylic polyols, hydrocarbon- or ester-based solvents, metal-based pigments, and wetting / dispersing agents or defoamers / The substance which mixed additives, such as a leveling agent, can be used. As a composition example, it can form with an acrylic polyol resin 36-40%, a solvent 33-40%, an inorganic pigment 20-25%, and an additive 1-2%. In addition, the solvent 33 to 40% may be formed by mixing 10-15% hydrocarbon solvent and 23-25% ester solvent which is a low boiling point solvent. The second pattern, which is a metal pattern, may basically implement a light blocking effect.

In the case of forming a stacked structure of two pattern structures, a diffusion pattern and a light shielding pattern as in the present embodiment, at least one material selected from CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and silicon may be used as the diffusion pattern as the first pattern. It can be implemented in a structure formed by a diffusion pattern formed using a light shielding ink including a.

(c) In addition, the optical pattern according to the present invention may be formed of a superimposed printing structure of a triple structure.

That is, the intermediate layer of the optical pattern may be implemented as a light shielding pattern layer composed of a metal pattern, and a structure for implementing a diffusion pattern on the upper and lower portions thereof.

The light shielding pattern (second pattern), which is the metal pattern, is formed as a printed pattern using a light shielding ink including a material in which Al or Al is mixed with TiO ₂ as described above. ) And (b) may be implemented to form a diffusion pattern described above.

For example, the first and third patterns, which are the outermost patterns, are configured as diffusion patterns, but TiO ₂ or At least one material selected from CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon, or TiO ₂ Wow It may be composed of a light shielding ink layer containing a material of any one of CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon. In addition, each pattern (first, second, third pattern) constituting the optical pattern can be formed in the thickness of 4 ~ 100㎛.

5 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 .

6 is an operational state diagram showing an operation state of the structure of the backlight unit according to the present invention described above. (The overall configuration and operation will be described with reference to the basic structure diagram of FIG. 2).

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 can use a side view LED (side view LED). 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. In this case, the resin layer 140 may include a bead 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. 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 addition, in the structure of the backlight unit according to the present invention, in particular, in the above-described structure, the present invention is the optical pattern between the resin layer 140 and the optical pattern 151 formed on the surface of the diffusion plate 150 A surface treatment layer (not shown) may be further provided to planarize pattern irregularities of the air gap, and the air layer may be formed due to a step generated when the optical pattern 151 of the diffusion plate is adhered to the resin layer 140 disposed below the diffuser plate. In order to exclude the difference between the dark portion and the bright portion generated by the formation, it is preferable to implement a flattened layer (layer) structure to cover the step of the entire optical pattern 151. In addition, the surface treatment layer is more preferably to improve the adhesion using the same material as the resin layer 140.

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 .

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.

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 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
160: prism sheet

Claims (16)

A plurality of LED light sources formed on the printed circuit board;
A resin layer stacked on the printed circuit board having a structure filling the LED light source and diffusing the emitted light forward;
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 optical pattern is formed on the surface of the diffusion plate, a backlight unit formed of at least one or more layers, or a backlight unit is formed of a structure in which a light shielding pattern for blocking light to the diffusion pattern is combined.
delete The method according to claim 1,
The optical pattern is
A backlight unit formed of a first pattern, which is a diffusion pattern formed by using a light shielding ink including at least one selected from TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and a mixture of two or more materials.
The method according to claim 1,
The optical pattern is a first pattern which is a diffusion pattern for diffusing light;
The backlight unit is formed of a second pattern that is a light shielding pattern formed on the upper or lower portion of the first pattern.
The method according to claim 1,
The optical pattern may include a second pattern, which is a light shielding pattern printed on the upper or lower portion of the first pattern, which is a diffusion pattern that partially diffuses or shields the emitted light, and is printed to block or reflect the emitted light;
And a third pattern which is a diffusion pattern formed in a structure covering the first and second patterns.
The method according to any one of claims 3 to 5,
The first pattern is TiO ₂ or TiO ₂ And a material comprising CaCo ₃ .
The method of claim 6,
The first pattern is a backlight unit, characterized in that the thickness of 4 ~ 100㎛.
The method according to claim 4 or 5,
The second pattern is,
And a light blocking ink including Al or a material in which TiO ₂ is mixed with Al.
The method according to claim 8,
The first pattern or the second pattern further comprises a bead (Bead) to shield the diffused light out.
The method according to claim 8,
The second pattern is a backlight unit, characterized in that the thickness of 4 ~ 100㎛.
The method according to claim 5,
The third pattern is TiO ₂ Or a material comprising TiO ₂ and CaCo ₃ .
The method of claim 11,
The third pattern is a backlight unit, characterized in that the thickness of 4 ~ 100㎛.
The method according to any one of claims 1 and 3 to 5,
The backlight unit,
The backlight unit further comprises a reflective film on which at least one reflective pattern is printed.
The method according to claim 13,
The reflection pattern is,
TiO ₂ Or a reflective ink including Al ₂ O ₃ .
The method according to claim 13,
The interior of the resin layer further comprises a bead (Bead) to reflect or diffuse light (Bead).
Side view LED is used as a light source,
A plurality of LED light sources formed on the printed circuit board;
A resin layer stacked on the printed circuit board having a structure filling the LED light source and diffusing the emitted light forward;
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 optical pattern may be formed on a surface of the diffusion plate, and may be formed of a diffusion pattern formed of at least one layer, or may be formed in a structure in which a light shielding pattern that shields light from the diffusion pattern is combined. Liquid crystal display comprising a backlight unit.

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