KR101225612B1 - 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 diffuser plate on which an optical pattern for blocking or reflecting light transmitted through the resin layer is printed, wherein the optical pattern includes a light blocking ink including an acrylic polyol resin, a hydrocarbon-based and ester-based solvent, and a pigment. It is characterized in that formed using.
According to the present invention, a light shielding ink capable of realizing an optical pattern capable of shielding or diffusing light on a surface of a diffuser plate of a backlight unit may be provided to further secure light uniformity and a blocking effect of yellow light due to a combination of a diffusion pattern and a metal pattern. By implementing the has the effect of deriving a reliable 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 provide a light shielding ink that can implement an optical pattern capable of blocking or diffusing light on the surface of the diffuser plate of the backlight unit and further the diffusion pattern and It is to provide a backlight unit that can achieve a reliable light quality by securing the uniformity of light and blocking the yellow light by the combination of metal patterns.

As a means for solving the above problems, the present invention is a plurality of LED light source formed on a printed circuit board; and a resin layer laminated on the LED light source, to diffuse the light emitted forward; And a diffuser plate on which an optical pattern for blocking or reflecting light transmitted through the resin layer is printed, wherein the optical pattern includes a light blocking ink including an acrylic polyol resin, a hydrocarbon-based and ester-based solvent, and a pigment. It is possible to provide a backlight unit, characterized in that formed using.

In particular, the optical pattern 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 layer is combined.

In this case, the first light-shielding ink for forming the diffusion pattern is 20 to 25% of acrylic polyol resin, 20 to 29% of hydrocarbon and ester solvents, and 50 to inorganic pigments based on the total weight of the first light-emitting ink. 55% may be included, and the inorganic pigment may use TiO ₂ or Al ₂ O ₃ .

Alternatively, the second light-shielding ink for forming the diffusion pattern described above, 20 to 25% of the acrylic polyol resin, 20 to 30% of hydrocarbon and ester solvents, inorganic pigments 45 It may comprise ~ 55%, in this case, the inorganic pigment, any one selected from CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon, or a mixture of TiO ₂ in any one selected material. It is available.

The light shielding pattern constituting the optical pattern according to the present invention is formed by using a third light shielding ink including an inorganic pigment containing an acrylic polyol resin, a hydrocarbon-based and ester-based solvent, and a metal material. In this case, 36 to 40% of the acrylic polyol resin, 33 to 40% of the hydrocarbon and ester solvents, and 20 to 25% of the metal pigment are used. In particular, the metal pigment may be used including Al or a mixture of Al and TiO ₂ .

In addition, the backlight unit according to the present invention may further include a reflective film having a reflective pattern stacked on the printed circuit board, the reflective pattern is formed on the reflective film, the reflective pattern is acrylic polyol (Acryl Polyol) may comprise 20 to 25% of resin, 20 to 29% of hydrocarbon and ester solvents, and 50 to 55% of inorganic pigments.

According to the present invention, a light shielding ink capable of realizing an optical pattern capable of shielding or diffusing light on a surface of a diffuser plate of a backlight unit may be provided to further secure light uniformity and a blocking effect of yellow light due to a combination of a diffusion pattern and a metal pattern. By implementing the has the effect of deriving a reliable 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 table showing a composition example of the ink constituting the optical pattern and the reflective pattern according to the present invention.
4 is a view illustrating various embodiments of an optical pattern according to the present invention.
5 is a view showing a manufacturing example implementing the optical 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.

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 A diffusion pattern formed using a light shielding ink including any one or more materials, and a light shielding pattern using a light shielding ink including Al or a mixture of Al and TiO ₂ may be implemented.

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 each of the upper and lower portions thereof to implement a diffusion pattern. 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.

3 illustrates the composition ratio of the light shielding ink and the reflective ink constituting the above-described optical pattern and reflective pattern as an example. 1, 2, and 3 degrees of the light shielding ink shown in the illustrated table implement a diffusion pattern, respectively, and FIG. 2 shows a composition example of the light shielding ink implementing the light shielding pattern. The above-described shading ink may have a different structure depending on the structure of the optical pattern to be formed, and a configuration thereof will be described with reference to FIG. 4.

3 and 4, the optical pattern according to the present invention may be formed in a structure that is printed on the upper or lower surface of the diffusion plate 150, and (a) one pattern layer (first pattern; 151a). (B) the second pattern 151b is superimposed on the first pattern, or (c) the first and second patterns are printed thereon, The third pattern may be formed in a triple layer structure for overprinting. The superimposed printing structure refers to a structure that forms one pattern and prints another pattern shape on the upper portion thereof.

1. Implement optical pattern with single layer diffusion pattern

As shown in (a), when the optical pattern is implemented on the surface of the diffusion plate 150 by printing, it may be formed in a structure having a single diffusion pattern.

That is, it is preferable to print by using a light shielding ink containing TiO ₂ basically, so as to implement an effective light shielding effect and at the same time 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 . As with the shading ink of FIG. 3, 20 to 25% of acrylic polyol resin, 20 to 29% of solvent (5 to 10% of hydrocarbon, 15 to 19% of hydrocarbon), and TiO ₂ 50 as inorganic pigment A mixture of ˜55% and an additive of 1% to 2% (0.5% to 1% of a silicon-based wet dispersion agent and 0.5% to 1% of a defoaming leveling agent of a silicon type) may be used. In this case, in the case of the inorganic pigment, those having a particle size of 500 to 550 nm can be used.

Alternatively, such a single layer diffusion pattern may use the light shielding ink of FIG. 1.

That is, 20 to 25% of acrylic polyol resin, 20 to 29% of solvent (5 to 10% of hydrocarbon, 15 to 19% of ester), and 20 to 20% of TiO ₂ and CaCO3 as inorganic pigments. What mixes -35% and the additive 1-2% (0.5-1% of a silicone type moisture dispersing agent, 0.5-1% of a defoaming leveling agent of a silicone type) can be used. In this case, in the case of the inorganic pigment, those having a particle size of 500 to 550 nm can be used. In this case, in particular, CaCO ₃ has the function of subtracting the exposure of yellow light to finally realize the white light to realize a more stable light, CaCO ₃ In addition, as described above, a large particle size such as BaSO ₄ , Al ₂ O ₃ , or silicon beads, and inorganic materials having a similar structure may be used. In this case, CaCO ₃ may be used having a particle size of 1 ~ 2㎛.

2. Formation of Two-layered Optical Pattern (Diffusion Pattern + Shading Pattern)

As shown in (b), the optical pattern of the superimposed printed structure may be implemented.

That is, another optical pattern according to the present invention is formed to implement a double structure in which a diffusion pattern (first pattern) for implementing a diffusion or shading effect and a light shielding pattern (second pattern) for implementing a shading effect are superimposed. can do. 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 this case, Al used as the inorganic pigment may have a particle size of 5 ~ 15㎛.

In the case of forming a stacked structure of two pattern structures of a diffusion pattern and a light shielding pattern as in the present embodiment, it is preferable to select and apply one of the light shielding ink of FIG. 1 and the light shielding ink of FIG. Of course it is possible.

3. Optical pattern of three-layer structure (diffusion pattern + shading pattern + diffusion pattern)

As shown in (c), the optical pattern according to the present invention may be formed as a superimposed printed 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 by using the light shielding ink of FIG. 2 including a material in which TiO ₂ is mixed with Al or Al, and above or below the metal pattern. It is possible to implement a structure in which a diffusion pattern is formed using the light shielding inks of FIGS. 1 and 3 described above in steps (a) and (b). Of course, the diffusion patterns stacked above or below the light shielding pattern may be formed in different stacking orders.

In any case, each of the diffusion and light shielding patterns constituting the optical pattern may have a thickness of 4 to 10 μm.

5 illustrates an example of implementing the above-described optical pattern.

That is, as shown in the illustrated example, the diffusion pattern 151a and the light shielding pattern 151b may be printed on the diffusion plate 150. Of course, the present embodiment has a structure superimposed in a double structure, as described above, of course, can be formed in a single layer or triple structure. 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. In addition, it is preferable in view of light efficiency that the optical pattern of the illustrated structure is formed by adjusting the pattern density so that the pattern density becomes lower as the LED light source moves away from the emission direction.

6 is an operational state diagram showing an operating state of the structure of the backlight unit according to the present invention with reference to FIG. 6 (total structure 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.

The reflective film 120 is stacked on the printed circuit board, and the LED light source 111 protrudes to the outside through the hole 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 region farther from the emission direction than the region closer 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 .

The composition of the reflective ink constituting such a reflective pattern is exemplified through FIG. 3 as follows. The reflective ink is based on the weight of the total reflective ink, acrylic polyol resin 20-25%, solvent 20-29% (hydrocarbon 5-10%, ester 15-19%), inorganic pigments TiO ₂ 50-55%, A mixture of additives 1 to 2% (silicone type wet dispersion agent 0.5 to 1%, silicone type defoaming leveling agent 0.5 to 1%) can be used.

As shown in FIG. 6, the backlight unit according to the present invention emits light laterally from the side emitting type LED 111, and the emitted light is reflected from the resin layer 140 formed instead of the structure of the conventional light guide plate. In this case, the reflection efficiency is further increased by the reflective film 120 and the reflective pattern 130, so that light can be guided 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 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.

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 (12)

A plurality of LED light sources formed on a printed circuit board, and a resin layer stacked on the LED light sources to diffuse and radiate the emitted light forward; And a diffuser plate on which an optical pattern for blocking or reflecting light transmitted through the resin layer is printed.
The optical pattern is a backlight, characterized in that the first pattern formed using a light shielding ink containing an inorganic pigment consisting of acrylic polyol (Acryl Polyol) resin, hydrocarbon and ester solvents, TiO ₂ or Al ₂ O ₃ unit.
The method according to claim 1,
The first pattern is a diffusion pattern printed by the first light blocking ink,
The first light blocking ink for forming the diffusion pattern,
A backlight unit comprising 20 to 25% of an acrylic polyol resin, 20 to 29% of hydrocarbon and ester solvents, and 50 to 55% of inorganic pigments, based on the total weight of the first light-blocking ink.
The method according to claim 1,
The optical pattern,
And a second pattern which is a diffusion pattern printed on the first pattern.
The method according to claim 3,
The second light blocking ink for forming the second pattern,
It comprises acrylic polyol (Acryl Polyol) resin, hydrocarbon-based, ester-based solvents and all inorganic pigments, the inorganic pigment is made of any one selected from CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon, or CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , Silicon comprising a mixture of TiO ₂ in any one of the materials selected from, the backlight unit.
The method of claim 4,
The second light blocking ink for forming the second pattern,
A backlight unit comprising 20 to 25% of acrylic polyol resin, 20 to 30% of hydrocarbon and ester solvents, and 45 to 55% of inorganic pigments, based on the total weight of the second shading ink.
The method according to claim 3,
The optical pattern,
And a third pattern which is a light shielding pattern printed on the first pattern and the second pattern.
The method of claim 6,
The third pattern is,
And a third shading ink including an inorganic pigment including an acrylic polyol resin, a hydrocarbon-based and ester-based solvent, and a metal material.
The method of claim 7,
The third light blocking ink constituting the light blocking pattern is
A backlight unit comprising 36 to 40% of acrylic polyol resins, 33 to 40% of hydrocarbon and ester solvents, and 20 to 25% of metal pigments, based on the total weight of the third light-blocking ink.
The method according to claim 8,
The metal pigment is a backlight unit, characterized in that it comprises Al or a mixture of Al and TiO ₂ .
The method according to claim 8,
The backlight unit includes:
And a reflective film having a reflective pattern stacked on an upper surface of the printed circuit board.
The method of claim 10,
The reflective pattern is formed on the reflective film,
The reflective pattern is a backlight unit comprising 20 to 25% of acrylic polyol (Acryl Polyol) resin, 20 to 29% of hydrocarbon and ester solvents, 50 to 55% of inorganic pigments.
Side view LEDs;
A resin layer stacked on the side light emitting diodes to diffuse outgoing light forward; And
And a diffuser plate on which an optical pattern for blocking or reflecting light transmitted through the resin layer is printed.
The optical pattern includes a backlight unit which is a first pattern formed using a light blocking ink including an inorganic pigment composed of an acrylic polyol resin, a hydrocarbon-based and ester-based solvent, and TiO ₂ or Al ₂ O ₃ . LCD display device.

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