KR100682325B1 - Heat radiation coating component for back-light unit, method of forming heat radiation coating layer, and back-light unit with heat radiation coating layer - Google Patents

Abstract

A radiation coating agent, a method for forming a radiation coating layer, and a backlight unit having the radiation coating layer are provided to effectively radiate the heat generated in the backlight unit to the outside, thereby extending the lifetime of the backlight unit and reducing the possibility of mis-operation of the backlight unit. A backlight unit comprises a substrate chassis(108) and a plurality of light sources formed on the substrate chassis. A radiation coating layer(110) is formed on a rear surface of the substrate chassis to radiate the heat generated from the light sources. The radiation coating layer has at least one of an aluminum anodizing layer and a ceramic coating layer. The ceramic coating layer includes SiO2 as a matrix, at least one component selected from a group consisting of MnO2, Al2O3, SiC, Fe2O3, TiO2, C, K2O, Na2O, and V2O5, as a filler, and Ag as a binder.

Description

Heat radiation coating component for back-light unit, method of forming heat radiation coating layer, and back-light unit with heat radiation coating layer}

1 is a cross-sectional view of a backlight unit using LED as a light source.

2 is a flowchart schematically illustrating a step of forming a heat dissipation coating layer on a backlight unit.

3 is a flowchart illustrating a modification of FIG. 2.

Figure 4 is a graph showing the temperature change with time before and after the heat radiation coating treatment.

<Description of Symbols for Main Parts of Drawings>

100: LED package 102: reflective cover

104: reflective plate 106: metal PCB

108: substrate chassis 110: heat dissipation coating layer

112: diffusion plate 114: DBEF-D sheet

116: BEF sheet 118: diffusion sheet

The present invention relates to a heat dissipation coating agent of a direct type back light unit, a heat dissipation coating layer forming method, and a backlight unit having such a heat dissipation coating layer. The present invention relates to a heat dissipation coating agent for dissipating heat generated in a backlight unit using the same, a method of forming a heat dissipation coating layer, and a backlight unit having such a heat dissipation coating layer.

In general, a flat panel display is classified into a light emitting type and a light receiving type, and the light emitting type includes a cathode ray tube (CRT), an electroluminescent (EL) element, and a plasma display panel (PDP). And the light-receiving type include Liquid Crystal Display (LCD).

 Since the LCD itself is a light-receiving element that emits light and does not form an image, but receives light from the outside to form an image, a separate light source, for example, a so-called backlight is installed to allow an image to be observed in a dark place. .

These backlights for LCD are classified into direct type and edge type according to the installation position of the light source.In the method of generating white light using the LED as a light source, white light is mixed by optically mixing red and green (RGB) LEDs. There is an RGB LED method for generating a light emitting diode, a method for mixing an ultraviolet LED and a red cyan phosphor, and a binary complimentary method for mixing a blue LED and a yellow phosphor. The LED light source has an advantage that it is not only fast response time compared to the CCFL used as a light source in the past, but also does not contain heavy metals such as mercury and is a solid solid device, which is environmentally friendly. In particular, the RGB LED system has excellent color expressing ability as compared to CCFL and other LED methods, which are conventionally used as a light source, and has been adopted for LED backlights for high-quality LCD TVs.

However, in the case of the conventional LED backlight unit, there is a limit to the heat generated in the LED package that serves as a light source through the substrate chassis. That is, since a plurality of LED packages are installed in a unit space, heat generated from the LED package overlaps with heat generated from adjacent LED packages, and thus, heat radiation through a substrate chassis having a flat shape is limited.

Therefore, in the conventional case, when heat is not emitted through the substrate chassis, heat is accumulated in the LED package, thereby reducing the lifetime of the LED package or causing an operation error.

The present invention is to solve the above problems, an object of the present invention is to discharge heat generated from a light source such as an LED package to the outside of the backlight unit can be minimized to minimize the amount of heat remaining inside the backlight unit. To provide a heat dissipation coating agent of the backlight unit, a heat dissipation coating layer forming method, and a backlight unit having such a heat dissipation coating layer.

The heat dissipating coating agent of the backlight unit according to the present invention for achieving the above object, SiO ₂ as a matrix, MnO ₂ , Al ₂ O ₃ , SiC, Fe ₂ O ₃ , TiO ₂ , C as a filler And at least one component selected from the group consisting of K ₂ O, Na ₂ O and V ₂ O ₅ , and Ag as a binder.

Here, the heat dissipation coating agent may further include at least one component selected from the group comprising Cr ₂ O ₃ , B ₂ O _3, and Li ₂ O as a filler.

More specifically, the SiO ₂ component is preferably 30 to 45% by mass percentage.

On the other hand, the heat radiation coating layer forming method of the backlight according to the present invention,

Degreasing the prepared substrate;

Blasting to give a surface roughness to the substrate chassis;

Blowing air;

An electrolyte film deposition step of depositing an electrolyte film on the substrate chassis;

Masking the substrate chassis;

Preheating the substrate chassis;

Forming a ceramic coating on the substrate chassis;

Firing the substrate chassis.

Meanwhile, the masking step may be further performed after the step of blowing the air and before the electrolyte film deposition step.

Here, in the electrolyte film deposition step, the substrate chassis is anodized and colored.

In particular, the substrate chassis is anodized and colored black.

In addition, the color of the substrate chassis is preferably controlled by adjusting the electrolyte.

In addition, the firing temperature of the firing step is preferably 80 ℃ to 150 ℃.

The ceramic coating forming step is preferably carried out by dipping or electrostatic spraying.

On the other hand, the backlight unit according to the present invention,

A substrate chassis;

It is provided on the substrate chassis and has a plurality of light sources for generating light,

A heat radiation coating layer applied to the substrate chassis to radiate heat generated from the light source,

The thermal radiation coating layer comprises an aluminum anodized layer anodized aluminum; Group comprising SiO ₂ as matrix and MnO ₂ , Al ₂ O ₃ , SiC, Fe ₂ O ₃ , TiO ₂ , C, K ₂ O, Na ₂ O and V ₂ O ₅ as filler A ceramic coating layer comprising at least one component selected from Ag and Ag as a binder; At least one of the.

Here, at least one component selected from the group containing Cr ₂ O ₃ , B ₂ O _3, and Li ₂ O may be further provided as a filler.

In addition, the SiO ₂ component is preferably 30 to 45% based on the mass percentage.

Meanwhile, a pattern may be formed on the rear surface of the substrate chassis.

Hereinafter, a heat dissipation coating agent, a heat dissipation coating layer forming method, and a backlight unit having a heat dissipation coating layer according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view of a unit LED package of a backlight unit having an LED heat dissipation coating layer of the present invention.

The LED package 100 installed on the substrate chassis 108 and serving as a light source is a combination of an LED and an LED lens. In addition, the LED package generates and irradiates light in a predetermined direction. A metal printed circuit board (PCB) 106 is disposed between the substrate chassis 108 and the LED package 100. Although not shown in detail in FIG. 1, the metal PCB 106 is a structure in which an insulating layer is formed on a plate made of aluminum and a conductive metal such as copper is provided on the insulating layer.

Meanwhile, the LED package 100 and the reflection plate 104 are installed on the metal PCB 106 positioned on the substrate chassis 110. That is, the LED package 100 is installed in the middle of the installation of the reflective plate on the metal PCB 106.

The periphery of the LED package is mounted downward to the LED edge reflective cover 102 made of a skirt shape to reflect the light generated from the LED package 100 in a predetermined direction to control the path of the light.

On the other hand, the light generated from the LED package 100 is reflected on the reflecting plate 104 and the reflecting cover 102 and then proceeds toward the exit surface direction (the upper direction in the drawing) of the backlight unit. Diffusion plate 112 is disposed spaced apart from 100.

A diffusion sheet 118, a BED sheet 116 (brightness enhancement film sheet) and a DBEF-D sheet 118 (dual brightness enhancement film sheet) may be sequentially stacked on the upper surface of the diffusion plate 112.

The diffusion plate 112 and the optical sheets disposed thereon serve to improve the scattering of the emitted light to improve the brightness of the light and to correct the difference in the local brightness to make the brightness constant.

On the other hand, when the LED package 100 operates to generate light, heat is generated in the LED package 100, and heat generated from the LED package 100 is radiated through the lower structure in which the LED package is mounted. In order to better heat dissipate heat generated from the LED package 100, a pattern (not shown) may be formed on the rear surface of the substrate chassis 108 to increase the heat dissipation area. In addition, the heat dissipation coating layer 110 is formed on the rear surface of the substrate chassis 108.

Accordingly, heat generated in the LED package 100 is transferred to the substrate chassis 108 via the metal PCB 106, and the heat transfer coating layer formed on the rear surface of the substrate chassis 108 is transferred to the substrate chassis 108. It is discharged through the outside.

The heat dissipation coating layer may be a double layer structure in which an anodized aluminum anodized layer and a ceramic coating layer of a ceramic material are formed, or may be a single layer composed of only one of the two layers.

The aluminum anodizing layer is a layer colored in black by controlling the electrolyte in a known anodizing process, that is, anodizing. Thus, its surface is formed a film of Al ₂ O _3.

On the other hand, the ceramic coating layer is SiO 2 as a matrix (matrix), MnO ₂ , Al ₂ O ₃ , SiC, Fe ₂ O ₃ , TiO ₂ , C, K ₂ O, Na ₂ O and V ₂ O as a filler (filler) At least one component selected from the group containing ₅ , and Ag as a binder.

In addition, at least one component selected from the group containing Cr ₂ O ₃ , B ₂ O _3, and Li ₂ O may be further provided as a filler.

The components of the ceramic coating layer exhibiting the optimal emissivity according to the experiment are shown in the table below.

Ingredient

ingredient Usage Mass fraction (%) ingredient Usage Mass fraction (%)

SiO ₂ matrix 30-45 Cr ₂ O ₃ Filler Filler 0-3 MnO ₂ filler 1-5 B ₂ O ₃ filler 0-3 Al ₂ O ₃ filler 1-25 K ₂ O filler 4-10 SiC filler 1-25 Li ₂ O filler 0-3 Fe ₂ O ₃ filler 4-10 Na ₂ O filler 5-10 TiO ₂ filler 8-15 V ₂ O ₅ filler 4-10 C filler 8-15 Ag filler 1-5

According to the ingredient table, the ceramic coating layer contains a plurality of components as a filler in a matrix composed of SiO 2, and Ag binds them as a binder.

Here, SiO 2 is a sol state dispersed in a colloidal state in the liquid.

On the other hand, the filler and the binder is a nano-component material of the particle size of several tens to hundreds of nanometers. In addition, the ceramic coating layer of such a component becomes an electrically insulating coating layer.

On the other hand, the emissivity (?) Of general aluminum, that is, the ratio of the radiant energy radiated from the actual material surface and the black body radiated from the black body, is about 0.02 to 0.1, whereas the emissivity of the ceramic coating layer of these components is 0.92 or more. Very high.

The present invention also describes a method of forming a heat dissipation coating layer capable of effectively dissipating heat generated from the substrate chassis 108.

2 and 3 are process flow diagrams for a process of two embodiments of forming a heat dissipation coating layer having the above components in a substrate chassis.

According to FIG. 2, first, a step S1 of degreasing is performed to wash a portion where a coating layer is to be formed on a substrate chassis. Subsequently, a step S2 of blasting the surface to give a surface roughness of a certain level on the rear surface of the substrate chassis to widen the heat dissipation area is performed.

When the blasting operation is completed, the air blowing step (S3) is performed to blow off the foreign matter on the substrate chassis. Subsequently, the substrate chassis is subjected to the electrolyte film deposition step S4. In this step, the substrate chassis is subjected to an anodizing process to form an oxide film on the surface thereof, and also to control and color the electrolyte. Through the coloring process, the substrate chassis is color coded.

Subsequently, a masking step S5 for exposing only the portion where the ceramic coating is to be formed and covering other portions is performed, and then undergoes a preheating step S6. The preheating step (S6) is a preliminary step to ensure that the coating of the ceramic coating layer is performed well.

Subsequently, a coating step S7 of forming a ceramic coating layer of the above-described component is performed. This coating step S7 includes dipping and coating the substrate chassis with the ceramic coating, or applying the ceramic coating to the substrate chassis using a known electrostatic spray method.

After the coating step (S7) is subjected to a firing step (S8) for firing so that the coating layer is completely attached to the substrate chassis. The firing step is preferably carried out at a temperature of about 80 ℃ to 150 ℃.

Although not separately illustrated in FIG. 2, after the firing step, the step of inspecting and packing the product may be performed.

3 is a modification of the coating layer forming method of FIG. 2, after the air blowing step S3 is performed, before the electrolyte film deposition step S4 is performed, the masking step S5 to expose only the portion where the deposition will occur. Same as the case of FIG. 2 except that ') is additionally performed.

Figure 4 is a graph showing the results of the parallel performance test of the LED backlight unit with a heat dissipation coating layer according to the present invention. In particular, Figure 4 shows the temperature change of the PCB after switching on the LED backlight by installing the temperature sensor on the PCB of the substrate chassis 108.

Referring to FIG. 4, when the pattern is formed on the rear surface of the substrate chassis, the anodizing layer is formed through the electrolytic pretreatment process, and the ceramic coating layer is formed to form the heat dissipation coating layer (A), the pattern is formed on the rear surface of the substrate chassis. The case where no heat dissipation coating process was performed (B) and the case where the surface of the substrate chassis was not formed without any pattern and flattened and without the heat dissipation coating treatment (C) were compared.

In all cases A, B, C, the temperature was about 27 ° C. before the LED backlight unit was initially turned on. When the power is turned on in the LED backlight unit, the temperature rises in each case. In the case of A, since the pattern is formed on the back of the substrate chassis, the heat dissipation area is wide and the heat dissipation coating layer is additionally formed. The temperature of the PCB until it is off is not very high compared to the case of B and C.

According to the experiment, the average value of the PCB temperature and the difference between the temperature and the initial temperature between 50 minutes and 65 minutes after the LED backlight unit is turned on are shown in the table below.

Temperature change table

type PCB average temperature between 50 and 65 minutes [℃] The difference between the average temperature of PCB and the initial temperature [℃] between 50 and 65 minutes A 73.59 54.79 B 88.46 61.06 C 89.76 61.76

As can be seen from the temperature change table and FIG. 4, the degree of dropping the temperature of the PCB by forming a pattern on the back of the substrate chassis is lower than that of the case of forming the heat dissipation coating layer according to the present invention on the back of the substrate. It can be seen.

Therefore, in addition to broadening the heat dissipation area for heat dissipation, when the heat dissipation coating layer according to the present invention is formed on the back of the substrate chassis, the heat dissipation action is significantly promoted so that the internal temperature of the LED backlight unit is maintained at an appropriate level. do.

As described above, according to the present invention, it is possible to effectively discharge heat generated inside the backlight unit due to long time use of the LED backlight unit to the outside of the backlight unit. In addition, due to this, the operating temperature of the backlight unit is lowered, so that the life of the backlight unit can be extended, and the risk of malfunction can be greatly reduced.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (14)

Group comprising SiO ₂ as matrix and MnO ₂ , Al ₂ O ₃ , SiC, Fe ₂ O ₃ , TiO ₂ , C, K ₂ O, Na ₂ O and V ₂ O ₅ as filler A heat dissipating coating agent for a backlight unit comprising at least one component selected from and Ag as a binder. The method of claim 1, A heat dissipating coating agent for a backlight unit, further comprising at least one component selected from the group consisting of Cr ₂ O ₃ , B ₂ O _3, and Li ₂ O as a filler. The method of claim 1, SiO ₂ component is a heat radiation coating agent for a backlight unit, characterized in that 30 to 45% by mass percentage. Degreasing the prepared substrate; Blasting to give a surface roughness to the substrate chassis; Blowing air; An electrolyte film deposition step of depositing an electrolyte film on the substrate chassis; Masking the substrate chassis; Preheating the substrate chassis; Forming a ceramic coating on the substrate chassis; And baking the substrate chassis. The method of claim 4, wherein And performing a masking step after performing the air blowing step and before performing the electrolyte film deposition step. The method of claim 4, wherein The electrolyte film deposition step is a method of forming a heat-dissipating coating layer of the backlight unit, characterized in that for anodizing (coloring) the substrate chassis. The method of claim 6, And the substrate chassis is anodized to be colored black. The method of claim 7, wherein The method of forming a heat-dissipating coating layer of the backlight unit, characterized in that the color of the substrate chassis is colored by controlling the electrolyte. The method of claim 4, wherein The firing temperature of the firing step is a method for forming a heat dissipation coating layer of the backlight unit, characterized in that 80 ℃ to 150 ℃. The method of claim 4, wherein The ceramic coating forming step is a heat-dissipating coating layer forming method of the backlight unit, characterized in that performed by dipping or electrostatic spraying. A substrate chassis; In the backlight unit provided on the substrate chassis and having a plurality of light sources for generating light, A heat radiation coating layer applied to the substrate chassis to radiate heat generated from the light source, The thermal radiation coating layer comprises an aluminum anodizing layer anodized aluminum; Group comprising SiO ₂ as matrix and MnO ₂ , Al ₂ O ₃ , SiC, Fe ₂ O ₃ , TiO ₂ , C, K ₂ O, Na ₂ O and V ₂ O ₅ as filler At least one component selected from, and a backlight unit comprising at least one of a ceramic coating layer comprising Ag as a binder (binder). The method of claim 11, And at least one component selected from the group consisting of Cr ₂ O ₃ , B ₂ O ₃ and Li ₂ O as a filler. The method of claim 11, SiO ₂ component is 30 to 45% based on the mass percentage. The method of claim 11, And a pattern is formed on the rear surface of the substrate chassis.

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