TWI493254B - Fabricating method of thick film on large area substrate, thick film structure thereof, and back light unit and lcd using the same - Google Patents

Description

Method for manufacturing thick film on large-area substrate and structure thereof and backlight unit and use thereof LCD of the backlight unit

The present invention relates to a method of coating a thick film on a large area substrate and a thick film; a backlight unit to remove a light guide plate to use the thick film to ensure its light efficiency; and an LCD using the backlight unit.

Generally, a liquid crystal display (LCD) is a pixel that can separately provide a data signal according to image information to pixels arranged in a matrix array, and adjust optical transmittance of the pixels (optical transmittance) ) to form a desired image. Since the LCD itself does not emit light, a backlight unit is mounted on the rear surface of one of the LCDs to display an image.

Referring to FIG. 1, a backlight unit 1 is formed such that a planar light guide plate 30 is disposed on a substrate 20, and a plurality of side view LEDs (only one of which is shown) It is arranged on one side of the light guide plate 30.

In the LED 10, the light L incident on the light guide plate 30 is reflected by a fine reflection pattern or a reflection plate 40 formed on one of the bottom surfaces of the light guide plate 30 to an upper portion, and is a self-light guide plate. 30 is emitted to provide backlighting to an LCD panel 50 located above the next light guide plate 30. As shown in FIG. 2, the backlight unit can be formed in a structure, which is further provided with a plurality of optical sheets such as a diffusion sheet 31; prism sheets 32, 33 (prism sheets); And a protective sheet 34 and the like between the light guide plate 30 and the LCD panel 50.

The backlight unit is configured to uniformly illuminate the LCD from the back side of the LCD (the LCD is not self-illuminating) to display an image, and further, the light guide plate is configured to uniformly light the light from a light source (eg, light) A plastic molded lens that is delivered to an integral surface of one of the LCDs and that provides brightness and uniform illumination to the backlight unit.

Therefore, the light guide plate is used as an essential component of the backlight unit; however, because of the thickness of the light guide plate, the overall product is difficult to achieve the thin and light requirements, and when the backlight unit has a large area, the image quality may be degraded. .

The present invention is to solve the above-mentioned drawbacks, and an aspect of the present invention relates to providing a backlight unit which is obtained by removing a light guide plate which is a constituent element in a conventional backlight unit, and using a film type resin layer (film type) Resin layer) to guide light, thereby reducing the number of light sources. Meanwhile, according to the structure of the backlight unit of the present invention, by providing a hard coating resin layer on the resin layer, the coupling force between the layers can be improved and the durability can be improved; and further, the overall thickness of one of the backlight units The system is shrunk, which increases the freedom of product design. In particular, an aspect of the invention resides in a technique for implementing a multilayer resin for the backlight unit wherein the uniformity and reliability of the coating is applied by applying a double coating method during coating Different directions To improve.

According to an embodiment of the present invention, there is provided a method for improving the thickness uniformity of a resin forming a thick film to promote adhesion to an upper plate; and the thick film can be implemented as a flat to improve the product. Reliability.

In addition, according to an embodiment of the present invention, there is provided a backlight unit in which a light guide plate is removed in a conventional backlight unit, and a resin layer having the above two-layer structure is used, whereby The thickness of the backlight unit is reduced. Meanwhile, by printing a hard coat resin layer on the upper surface of one of the resin layers, the resin layer can be protected, and the adhesion in each structure can be improved.

According to an embodiment of the present invention, there is provided a thick film on a large-area substrate, wherein when coating a thick film on a large-area substrate, uniformity and reliability of the coating are applied by applying a double coating method Improve in different directions.

In particular, a multilayer resin which is implemented in the above double coating method is used to remove a light guide plate which is a constituent element in a conventional backlight unit, and a structure in which a film type resin layer is used to guide light can be formed. So that the number of light sources can be reduced. In addition, the hard coating resin layer may be provided on the resin layer to enhance the coupling force between the layers and improve durability; and, the overall thickness of one of the backlight units is reduced, thereby increasing the degree of freedom in product design. .

In particular, one side of the LED can be directly mounted downward to significantly reduce the number of light sources and achieve optical characteristics; and a reflective film comprising a reflective microstructure on the resin layer and a diffusion Sheets are provided to enhance stable luminescent properties and optical uniformity optical properties.

The aspects, functions, and advantages of the above and other embodiments of the invention will be described in conjunction with the drawings.

Best Mode

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The same reference numerals will be assigned to the same elements in the illustrated explanation, and the repeated explanation will be omitted. It should be understood that the terms "first," "second," and the like are used herein to describe various elements; these elements are not limited to such terms. These terms are used to distinguish between components.

1. First embodiment

In Fig. 3, there is shown a flow of forming a resin layer (thick film) on a conventional large-area substrate. As shown in FIG. 3, the resin layer may be formed substantially as a metal jig formed on a base substrate S, and a thick film coating material is applied to the metal mold. On the inner surface of M, the metal mold M is then removed.

However, as shown in Fig. 3(b) (shown along the line A-A' in Fig. 3(a)), The surface tension of the covering material itself is such that when the thick film coating material C is applied to the inner surface of the metal mold M, a constant gap G is formed, and the coating is lowered due to the generation of the gap. Uniformity and reduce the reliability of a product such as protrusions of internal structures.

Therefore, according to an embodiment of the present invention, a resin layer (thick film) applied to a large-area substrate can be formed by applying the method shown in FIG.

Referring to FIG. 4, a manufacturing method according to an embodiment of the present invention may include a first step of coating a first resin on a base substrate 110 in a first direction X of a base substrate 110. This forms a first resin layer 120; and a second step of applying a second resin layer 130 to the upper surface of one of the first resin layers 120 in a second direction Y (S1 to S3).

In particular, in the first step, the base substrate 110 may be coated with the first resin in the first direction X, and then coated with a second resin in the second direction Y opposite to the first direction X.

In particular, in this case, the first resin and the second resin may be made of the same or different materials.

When the same material is used to manufacture the thick film, the reliability of adhesion between the first resin and the second resin can be enhanced, and uniformity can be improved. In addition, the errors of flatness caused by surface tension can be removed. In this case, the material of the first resin layer and the second resin layer may be a thermosetting resin. (thermosetting resin) or a photocurable resin, and one of the materials may comprise a urethane acrylate oligomer using a synthetic resin. Further, when the first and second resin layers, instead of the light guide plate of the backlight unit (which will be described in detail later), are used, they may be mainly formed of an urethane acrylate resin. For example, a mixture of an acrylic urethane oligomer and a polymer type polyacryl as a synthetic oligomer can be used. Of course, the mixture may further comprise a diluted type-reactive monomer having a low boiling point, mixed with isobornyl acrylate (IBOA) and hydroxylpropyl acrylate (HPA), 2-hydroxyethyl acrylate (2-HEA); and an additive, a photo initiator such as 1-Hydroxycyclohexyl Phenyl-Ketone, etc. An antioxidant can be mixed.

Further, when the first resin layer 120 and the second resin layer 130 are formed of different materials, either of the first resin layer 120 and the second resin layer 130 may preferably be formed of a transparent material. In addition, one of the beads for enhancing light reflection may be contained in the resin forming the first resin layer or the second resin layer of the above structure, and when the first resin layer 120 and the second resin layer 130 are a light guide plate of a backlight unit (which will be described later in detail), when used, the beads can be held according to the overall weight of the first region 0.01 to 0.03%.

In the manufacturing process of the thick film on the large-area substrate, the thickness uniformity and the flatness can be basically achieved by applying a double coating method in different directions when applying the large-area substrate, thereby improving It adheres to the upper plate and is used in a device such as a backlight unit in the future, thereby achieving reliable optical characteristics.

2. Second Embodiment

Hereinafter, a backlight unit in a second embodiment will be described in detail, in which a thick film on a large-area substrate having a multilayer resin structure implemented in the first embodiment is applied.

In the multilayer resin structure of the second embodiment, one of the second resin layers may be laminated on the upper surface of the first resin layer by a hard coating method, thereby protecting the first resin layer and improving The adhesion between the various structures.

FIG. 5 is a cross-sectional view showing a backlight unit according to an embodiment of the invention.

Referring to FIG. 5, the backlight unit includes a plurality of LED light sources 130 formed on the printed circuit board 110. A first resin layer 140 is used to diffuse and guide the light forward. The two resin layer 150 is formed on the first resin layer 140; and a diffusion sheet 160 is disposed on the second resin layer 150.

In addition, a die and a protective sheet may be further provided over the diffusion sheet 160. In particular, according to the present invention, one of the optical microstructures 161 for shielding or reflecting light may be disposed between the second resin layer 150 and the diffusion sheet 160. In this situation, The optical microstructure 161 may be integrally formed on one surface or the lower surface of the diffusion sheet 160, or may be integrally formed on one surface or the lower surface of the second resin layer 150, or may be integrally formed. Printing is performed on a transparent substrate disposed between the second resin layer 150 and the diffusion sheet 160.

In particular, the first resin layer 140 can be used to guide light forward without removing an existing light guide plate and replacing it with a film type resin; and preferably, it can be further laminated to the printed light emitting diode 230. Above the board. In addition, the second resin layer 150 formed on the first resin layer 140 may be formed as a hard coating layer on the upper surface of the first resin layer 140 to form another resin layer, thereby protecting the first resin layer 140, And improve the coupling force and adhesion between various structures such as optical microstructures, diffusers and the like.

The material forming the second resin layer 150 may be a resin including an oligomer, a monomer-type ultraviolet-curing resin, or a mixture thereof. In this case, the oligomer may use any one of acryl urethane, epoxy acrylate, polyester acrylate, and Acrylic Acrylate; The monomer may use a monofunctional monomer, a bifunctional monomer, a trifunctional monomer, and a tetrafunctional monomer. In addition, one of the hard coating resin layers may have a thickness of 10 Μm to 100 μm, and one of the hard coat resin layers may have a hardness corresponding to a pencil hardness: B to 2H.

A structure according to the present invention will be explained hereinafter.

At least one of the light emitting diodes 230 can be arranged above the base substrate 110 to emit light, and a side optical LED can be used in a preferred embodiment of the present invention. That is to say, with respect to the direction of the light from the light-emitting diode light source 230, a light source can be used, wherein the light passes through the light source and travels to the side instead of directly upward. In addition, the edge-lit LED can be directly mounted downward, so that a resin layer for performing a light diffusion and reflection function can be used to reduce the number of the entire light source, thereby reducing the overall thickness of the backlight unit. As shown in FIG. 5, a back cover B can be bonded to the lower surface of one of the base substrates 110 by an adhesive P.

The first resin layer 140 may be laminated to surround the light emitting diode light source 230, and may diffuse light from a light source in one side. That is, the first resin layer 140 can be used as a conventional light guide plate.

The first resin layer 140 may be formed of any resin material that can diffuse light. One of the main materials of the resin layer according to an embodiment of the present invention may be a resin containing an urethane acrylate oligomer. For example, a mixture of an acrylic urethane oligomer and a polymer type polyacryl as a synthetic oligomer can be used. Of course, the mixture may further comprise one having a low boiling point Diluted type-reactive monomer mixed with isobornyl acrylate (IBOA) and hydroxylpropyl acrylate (HPA), 2-hydroxyethyl acrylate, 2 -HEA); and an additive, a photo initiator such as 1-Hydroxycyclohexyl Phenyl-Ketone, etc., an antioxidant can be mixed.

In the first resin layer 140 or the second resin layer 150, one of the beads 141 for enhancing light diffusion and light reflection may be included. The beads 141 are 0.01 to 0.3% by weight based on the total weight of the entire first resin layer 140. That is, light emitted from the side of the LED can be diffused and reflected through the first resin layer 140 and the beads 141 to travel upward. Here, when a reflective film 220 and a reflective microstructure 121 (which will be described later in detail) are provided, this reflective function can be promoted. Generally, the thickness of a product occupied by a conventional light guide plate can be remarkably reduced by the above-mentioned resin layer, thereby making the product light and thin, and the resin layer, due to one of the ductile materials, can be Applied to a flexible display to achieve versatility.

In addition, the reflective film 220 can provide a reflective microstructure 121 via a white printing method to diffuse light from the source and promote light reflection. The reflective microstructure 121 can be printed using a reflective ink comprising any of TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , silicon, and PS.

The diffusion sheet 160 may diffuse through the first resin layer 140 to be emitted light, and includes an optical microstructure 161 formed on a lower surface of the diffusion sheet. The optical microstructure 161 can be a light shielding pattern to prevent the optical properties from being attenuated due to a very strong light intensity, or to avoid yellowing of the light, thereby partially implementing a light blocking effect. That is, the light-shielding microstructure can be printed using a light shielding ink to avoid light convergence. The optical microstructure can be implemented to adjust the degree of diffusion or to use a single optical microstructure to illuminate and thereby partially shield or diffuse light, rather than completely shielding only light. Additionally, preferably, the optical microstructures according to embodiments of the present invention can be implemented in a superposition printing structure of a composite pattern. The overlay printed structure can refer to a structure in which a single microstructure is printed and another microstructure is printed on the single microstructure.

In one example of the overlapping printed structure of the optical microstructure 161, the light-shielding ink may be used to comprise a diffusion microstructure formed by a light-emitting direction selected from at least one of TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and silicon. A lower surface of a polymer film to provide the diffusion microstructure; and a light-shielding ink comprising Al or a mixture of Al and TiO ₂ may be used to provide a light-shielding microstructure. That is, a two-layer structure having a diffusion microstructure formed on the surface of the polymer film in a black-and-white printing method and then forming a light-shielding microstructure on the diffusion microstructure (or vice versa) can be implemented.

It will be apparent that the shape of the microstructure varies depending on light efficiency, light intensity, and a light shielding ratio. The microstructure may be formed in a triple-layered structure, wherein the light-shielding microstructure (also a metal microstructure) is formed as an intermediate layer in a sequential laminated structure, and the diffusion microstructures are respectively formed For the upper and lower layers. Preferably, a three-layer structure is used in which a single diffusion microstructure is formed using TiO ₂ having an excellent refractive index, and the other diffusion microstructure is used with excellent light stability and The color sense of TiO ₂ is formed with CaCO ₃ , and the light-shielding microstructure is formed using Al having excellent concealment properties, thereby obtaining light efficiency and light uniformity.

In particular, CaCO ₃ can ultimately perform white light by attenuating the exposure of yellow light, thereby obtaining a relatively stable and efficient light; and in addition to CaCO ₃ , an inorganic material having a large particle size and a similar structure such as BaSO can be applied. ₄ , Al ₂ O ₃ , silicon, a bead, etc. Additionally, depending on the light efficiency, one of the microstructures of the optical microstructure can be adjusted to reduce the density of the microstructure as the microstructure becomes distant from the direction of illumination of the LED source.

In addition, the reflective film 220 according to an embodiment of the present invention may be laminated onto the printed circuit board 210, and the light emitting diode light source 230 may protrude to the outside through a hole formed in the reflective film 220. When the light-emitting diode light source 230 is implemented as a one-side light LED structure, as described above, the number of light sources can be significantly reduced, and the reflective microstructure can be implemented to significantly improve the reflectance of light.

As shown in FIG. 5, the reflective microstructure can be formed in one of the LED light sources, and in particular can be configured such that its microstructure density can be increased as the microstructure becomes farther away from the direction of illumination of the LED source. Additionally, the reflective microstructure can be printed using an ink comprising a reflective layer selected from at least one of TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and silicon.

The backlight unit according to an embodiment of the present invention can be implemented as one of light source illuminating light L, as shown in FIG. That is to say, in order to reduce the number of light sources, a light-emitting diode light source 230 of an edge-lit LED can be provided.

Further, the backlight unit according to an embodiment of the present invention can be applied to an LCD through the following structure and function. That is, the light is emitted from the light-emitting diode light source 230, and then reflected and diffused in the first resin layer 140 formed to replace the conventional light guide plate. Here, the reflection efficiency can be enhanced by the reflective film 220 and the reflective microstructure 121 so that the light can be guided forward. In this manner, light passing through the first resin layer 140 and the second resin layer 150 can be diffused or shielded through the optical microstructure 161, and the purified light has purified optical properties to improve uniformity. . Here, the light of an optical sheet such as a cymbal sheet 170, a polarizing plate 180 (DBEF) or the like is incident on the LCD panel in the form of a white light.

FIG. 7 illustrates a backlight unit in accordance with another embodiment of the present invention. In the backlight unit according to the present embodiment, the light is emitted from one side of the light-emitting diode light source 230 in one direction, and then formed in accordance with the present embodiment to replace one of the conventional light guide plates. The resin layer is diffused and reflected. Here, the reflection efficiency can be further improved by a reflective film 220 and a reflective microstructure 221 so that light can be directed forward. In this manner, the light passing through the first resin layer 240 can be diffused or shielded through one of the optical microstructures 261 formed on the diffusion sheet 260, and the purified light L passes through an optical sheet such as the cymbal sheet 270 or the like. It is incident on the LCD panel in the form of a white light. The resin layer may substantially include the first resin layer 240 and the second resin layer 250, and may be used as a substitute for a conventional light guide plate, thereby achieving flatness, thereby achieving reliable light diffusion. In this case, in the first resin layer 240 or the second resin layer 250, one bead may be included as described above. In addition, when the first resin layer 240 and the second resin layer 250 do not use the same material, either of the first resin layer 240 and the second resin layer 250 may include a transparent material as described above. In particular, the difference from the structure in FIG. 5 is that the optical microstructures 261 are formed on the lower surface of the diffusion sheet 260, and the optical microstructures 261 are filled in the second resin layer 250.

As described above, in the backlight unit according to the embodiment of the present invention, the light guide plate can be removed, and the edge-lit LED can be applied as a light source; the light can be guided by the diffusion and reflection of the resin layer to narrow the product. Thickness and reduce the number of light sources. Further, the hard coat resin layer may be printed on the upper surface of the resin layer to protect the resin layer and improve the adhesion between the respective structures. Moreover, the brightness reduction and uniformity which may occur due to the reduction of the light source can be adjusted by using the reflective microstructure and the light-shielding microstructure, thereby improving the optical properties.

While the embodiments have been described with reference to the embodiments of the embodiments the embodiments Therefore, the scope of the present invention should be construed as being included in the scope of the appended claims, and all modifications within the scope of the present invention should be construed as being included in the scope of the present invention. within.

1‧‧‧Backlight unit

10‧‧‧Side-light LEDs

20‧‧‧Substrate

30‧‧‧Flat light guide

40‧‧‧reflector

50‧‧‧LCD panel

31, 160, 260‧‧‧ diffuser

32, 33, 170, 270‧‧‧ pictures

34‧‧‧Protection film

110‧‧‧Base substrate

120, 140, 240‧‧‧ first resin layer

130, 150, 250‧‧‧ second resin layer

121, 221‧‧‧reflective microstructure

141‧‧‧ beads

161, ‧ ‧ ‧ optical microstructure

180‧‧‧Polarized film

210‧‧‧Printed circuit board

220‧‧‧Reflective film

230‧‧‧Lighting diode source

B‧‧‧Back cover

C‧‧‧Thick film coating material

G‧‧‧Fixed clearance

L‧‧‧Light

M‧‧‧ metal mold

P‧‧‧Adhesive

S‧‧‧ base substrate

S _1~ S ₃ ‧‧‧Steps

X‧‧‧ first direction

Y‧‧‧second direction

1 and 2 are structural diagrams of a backlight unit according to a prior art; FIG. 3 illustrates a method of applying a thick film to a conventional large-area substrate; and FIG. 4 is an embodiment of the present invention. For example, a process for forming a thick film on a large-area substrate is shown; FIG. 5 is a main portion of a structure of a backlight unit according to an embodiment of the invention; FIG. 6 is an embodiment of the present invention, An arrangement of an LED light source is shown; and FIG. 7 illustrates an application example of a backlight single source according to another embodiment of the present invention.

S ₁ ~S ₃ ‧‧‧Steps

110‧‧‧Base substrate

120‧‧‧First resin layer

130‧‧‧Second resin layer

X, Y‧‧ direction

Claims (20)

A thick film on a substrate comprising: a base substrate; a first resin layer laminated on the base substrate; and a second resin layer laminated on the first resin layer and having a hardness Greater than the hardness of the first resin layer, wherein the first resin layer or the second resin layer comprises a bead, which is 0.01 to 0.3 wt% of the weight of each of the resin layers, wherein the second resin layer The hardness corresponds to a pencil hardness of B to 2H. The thick film on the substrate of claim 1, wherein the first resin layer and the second resin layer are made of the same material. The thick film on the substrate of claim 1, wherein the second resin layer is formed of an oligomer or a monomeric ultraviolet curable resin, or a mixture thereof. The thick film on the substrate of claim 3, wherein the oligomer comprises any one of acrylic urethane, epoxy acrylate, polyester acrylate, and acrylic acrylate. The thick film on the substrate of claim 4, wherein the first resin layer comprises a mixture of an urethane acrylate oligomer and a polymer resin, and a monomer. The thick film on the substrate according to claim 5, wherein the single system comprises isobornyl acrylate (IBOA), hydroxylpropyl acrylate (HPA), and 2-hydroxyethyl acrylate. A mixture of 2-hydroxyethyl acrylate (2-HEA). The thick film on the substrate of claim 6, wherein the first resin layer further comprises a photoinitiator and an antioxidant. A method of manufacturing a thick film on a large-area substrate, comprising: coating a first resin on a base substrate in a first direction to form a first resin layer; and forming a second resin layer a second direction opposite to the first direction is provided on an upper surface of the first resin layer, wherein a hardness of the second resin layer is greater than a hardness of the first resin layer, wherein the first resin layer or the first The two resin layer comprises a bead which accounts for 0.01 to 0.3% by weight of each of the resin layers, wherein the hardness of the second resin layer corresponds to a pencil hardness of B to 2H. A backlight unit includes: a plurality of light emitting diode light sources mounted on a printed circuit board; a first resin layer laminated on the printed circuit board to embed the light emitting diode light sources, And guiding the emitted light to the front; a second resin layer laminated on the first resin layer and having a hardness greater than a hardness of the first resin layer; a diffusion sheet disposed on the second resin Above the layer; and an optical microstructure disposed between the second resin layer and the diffusion sheet, wherein the optical microstructure is formed as an overlapping structure, comprising using a layer selected from the group consisting of TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ A diffusion microstructure formed by the light-shielding ink of at least one of O ₃ and 矽, and a light-shielding microstructure formed by using a light-shielding ink comprising one of Al, Al or TiO ₂ . The backlight unit of claim 9, wherein the second resin layer is formed of an oligomer or a monomer type ultraviolet curable resin, or a mixture thereof. The backlight unit of claim 10, wherein the oligomer comprises any one of acrylic urethane, epoxy acrylate, polyester acrylate, and acrylic acrylate. The backlight unit of claim 10, wherein the second resin layer has a thickness of 10 to 100 μm. The backlight unit of claim 10, wherein one of the second resin layers has a hardness corresponding to a pencil hardness of B to 2H. The backlight unit of claim 10, wherein the first resin layer comprises a mixture of an acrylic urethane oligomer and a polymer resin, and isobornyl acrylate (IBOA), Acrylic acid A mixture of hydroxypropyl acrylate (HPA) and 2-hydroxyethyl acrylate (2-HEA). The backlight unit of claim 10, wherein the first resin layer or the second resin layer further comprises a bead, which accounts for 0.01 to 0.3 wt% of the total weight of the resin layers to increase Light reflection. The backlight unit of claim 9, wherein the optical microstructure is directly formed on a lower surface of the diffusion sheet or formed in a transparent manner between the diffusion sheet and the second resin layer. On one of the surfaces of the substrate. The backlight unit of claim 16, further comprising: a reflective film laminated on an upper surface of the printed circuit board and having a reflective microstructure formed thereon. The backlight unit of claim 17, wherein the reflective microstructure is printed using an ink comprising a reflective layer selected from at least one of TiO ₂ , CaCO ₃ , BaSO ₄ , Al ₂ O ₃ , and silicon. The backlight unit of claim 17, further comprising: a cymbal sheet or a protective sheet laminated on the diffusion sheet. An LCD comprising the backlight unit according to claim 9 and using a light-emitting diode as a light source, comprising: a first resin layer laminated to accommodate the light source, and a second resin layer printed On an upper surface of one of the first resin layers; A diffusion sheet is disposed on a hard coating resin layer and an optical microstructure.