KR101887623B1 - Printed-Circuit Board and Back Light Unit including the same - Google Patents

Abstract

The present invention relates to a light source; A printed circuit board including a circuit pattern region for mounting the light source, a heat radiation region for radiating heat generated from the light source, and a drill region between the circuit pattern region and the heat radiation region; And a light guide plate including a side surface facing the light source mounted on the circuit pattern region. Here, the drill region is thinner than the circuit pattern region and the heat radiation region.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a printed circuit board and a backlight unit including the printed circuit board.

The present invention relates to a printed circuit board and a backlight unit including the same.

Generally, the backlight unit includes a light source and a light guide plate that converts the light emitted from the light source into a surface light source, and is provided as a separate light source in a flat panel display device including a non-luminescent display panel. Here, a typical example of a flat panel display device including a non-luminescent display panel is a liquid crystal display (LCD).

Such a backlight unit can be divided into a direct type and an edge type depending on the arrangement region of the light source. The direct-type backlight unit directly irradiates the display panel with light as it includes a light source disposed in the display area of the flat panel display. On the other hand, since the edge type backlight unit is disposed in a non-display area (for example, a bezel) of the flat panel display device and includes a light source that emits light toward the side face of the light guide plate, As shown in FIG.

A cold cathode fluorescent lamp (CCFL) has been applied as a light source of a backlight unit. In recent years, however, a light emitting diode (LED) capable of realizing lower power consumption, Is applied.

However, when the light source is applied to a light emitting diode emitting more heat than other light source means, the backlight unit must have a separate heat dissipating means for emitting heat of the light emitting diode in order to prevent deterioration of the light emitting diode .

Accordingly, the backlight unit including the light source of the light emitting diode generally includes a heat dissipating member separately attached to a printed circuit board on which the light emitting diode is mounted, in order to emit a large amount of heat generated in the light emitting diode.

In order to improve the heat dissipation characteristics of the backlight unit, the surface area of the heat dissipation member must be increased. Since the width of the non-display area (for example, the bezel) of the flat panel display is limited, There is a problem with limit. Further, since a pressure sensitive adhesive material for adhering them is interposed between the printed circuit board and another heat radiation member, the heat radiation property due to the pressure sensitive adhesive material is expected to deteriorate.

In recent years, the flat panel display has become larger, and the backlight unit needs to include a larger number of light emitting diodes as much as that, so it is necessary to further improve the heat generating characteristics.

Accordingly, it is necessary to search for a method of effectively emitting heat of a light emitting diode while applying the light emitting diode as a light source.

The present invention provides a printed circuit board integrated with a heat dissipating means and a backlight unit including the same to improve heat dissipation characteristics.

According to an aspect of the present invention, there is provided a light emitting device including: a circuit pattern region for mounting a light source; A heat radiation region for radiating heat generated from the light source; And a drill region between the circuit pattern region and the heat dissipation region. Here, the drill region is thinner than the circuit pattern region and the heat radiation region.

According to another aspect of the present invention, A printed circuit board including a circuit pattern region for mounting the light source, a heat radiation region for radiating heat generated from the light source, and a drill region between the circuit pattern region and the heat radiation region; And a light guide plate including a side surface facing the light source mounted on the circuit pattern region. Here, the drill region is thinner than the circuit pattern region and the heat radiation region. In the printed circuit board, the printed circuit board has a shape in which the circuit pattern region and the heat dissipation region are bent with the drill region as an axis.

A printed circuit board according to the present invention includes a substrate base including a circuit pattern region, a heat radiation region, and a drill region. That is, the circuit pattern region in which the light source is mounted and the heat radiation region serving as the heat radiation means for emitting heat generated in the light source are integrated.

As a result, since the circuit pattern region and the heat dissipation region are integrated and realized without a separate bonding means, it is possible to prevent deterioration of heat dissipation characteristics by a separate bonding means.

Then, the printed circuit board is bent between the circuit pattern region and the heat radiation region with the drill region as an axis, and is engaged with the bottom cover of the display device with the circuit pattern region bent with respect to the heat radiation region. At this time, the circuit pattern region and the heat radiation region are disposed on mutually different surfaces.

Thus, in order to provide the heat dissipating means, it is not necessary to increase the width of the space in which the circuit pattern region is to be arranged, and thus the slimness of the flat panel display device can be improved.

In addition, the width of the heat radiation region can be increased regardless of the width of the space in which the circuit pattern region is to be arranged, and the surface area of the heat radiation region can be further increased, thereby further improving the heat radiation characteristics.

1 is an exploded perspective view illustrating a backlight unit according to an embodiment of the present invention.
2 is a perspective view showing the light source and the printed circuit board of FIG.
3 is a plan view of the printed circuit board of FIG.
4 is a cross-sectional view showing I-I 'of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In the drawings, the same reference numbers are used throughout the specification to refer to the same or like parts.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . Also, when an element is referred to as "comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

FIG. 1 is an exploded perspective view illustrating a backlight unit according to one embodiment of the present invention, and FIG. 2 is a perspective view illustrating a light source and a printed circuit board of FIG. 1. Referring to FIG. FIG. 3 is a plan view of the printed circuit board of FIG. 1, and FIG. 4 is a cross-sectional view taken along line I-I 'of FIG.

1, a backlight unit 100 according to an exemplary embodiment of the present invention includes a light source 110, a printed circuit board 120, a reflective sheet 130, a light guide plate 140, at least one optical sheet (not shown) 150).

The light source 110 may be a light emitting diode (LED).

The printed circuit board 120 includes a circuit pattern region 121 on which the light source 110 is mounted, a heat radiation region 122 for radiating heat generated in the light source 110, a circuit pattern region 121 and a heat radiation region 122, And a drill area 123 between them.

At this time, the printed circuit board 120 is coupled to the bottom cover (not shown) of the display device in such a manner that the circuit pattern region 121 and the heat radiation region 122 are bent together with the drill region 123 as an axis .

In other words, in combination with the reflective sheet 130, the light guide plate 140, and the at least one optical sheet 150, including the bottom cover (not shown) of the display, the printed circuit board 120 includes a curved drill area The circuit pattern region 121 and the heat radiation region 122 are arranged on a plane in which the circuit pattern region 121 and the heat radiation region 122 are different from each other. In this case, the circuit pattern region 121 and the heat radiation region 122 may be bent to each other at a predetermined angle, where the predetermined angle may range from 45 degrees to less than 180 degrees, 90 [deg.]).

In this manner, the circuit pattern region 121 and the heat radiation region 122 can be arranged in a planar space that is different from each other, and a space in which the circuit pattern region 121 is disposed (for example, a bezel of a display device) The width of the heat radiation region 122 can be increased regardless of the width of the heat radiation region 122 (region). In particular, the heat radiation area 122 may be arranged along a plane corresponding to the display area of the display device, and may be formed as large as the width of the display area of the display device. As a result, the surface area of the heat radiation region 122 is increased, and the heat radiation characteristics can be improved.

In the printed circuit board 120 of Fig. 1, the circuit pattern region 121 in which the light source 110 is mounted and the heat radiation region 122, which is the heat radiation means for emitting heat generated in the light source 110, are integrated.

The printed circuit board 120 will be described in more detail below.

The reflective sheet 130 is disposed on the heat radiation region 122 of the printed circuit board 120 and reflects light incident into the light guide plate 140 through the side surface of the light guide plate 140 toward the optical sheet 150 side. 1, a display panel (not shown) is disposed above the optical sheet 150, so that the light reflected by the reflective sheet 130 is irradiated to the display panel (not shown) .

The light guide plate 140 is disposed on the reflective sheet 130. The light guide plate 140 includes at least one side surface opposed to the heat radiation region 122 of the printed circuit board 120 and a circuit pattern region 121 of the printed circuit board 120. [ That is, at least one side surface of the light guide plate 140 faces the light source 110 mounted on the circuit pattern region 121.

The light guide plate 140 converts light emitted from a plurality of light sources 110, which are point light sources, into a surface light source.

The at least one optical sheet 150 may include a diffusion sheet 151, a prism sheet 152, and a protective film 153.

2 and 3, the light source 110 and the printed circuit board 120 according to an embodiment of the present invention will be described in more detail. 2 and 3 show the printed circuit board 120 in a state in which the circuit pattern region 121, the drill region 123, and the heat radiation region 122 are laid out side by side.

2, the light source 110 includes a body portion 111 including a cavity 112, a light emitting diode chip 123 mounted on the cavity 112, and a light emitting diode chip 123 electrically connected to the light emitting diode chip 123 (Not shown) for molding the cavity 112 and a molding member (not shown) for molding the cavity 112.

The light source 110 may be formed in a top view type in which the cavity 112 is corresponded to the surface of the printed circuit board 120 facing the light guide plate 140. To this end, the light sources 110 further include first and second lead terminals (not shown) spaced apart from each other in the cavity 112 and exposed to the bottom surface of the body portion 111. The light source 110 may be a chip on board (COB) type including a light emitting diode chip and a molding member covering the light emitting diode chip.

As shown in FIGS. 2 and 3, the printed circuit board 120 includes a substrate base 124.

The substrate base 124 includes a circuit pattern region 121, a heat radiation region 122, and a drill region 123. At this time, the heat dissipation area 122 and the drill area 123 may be regions formed only of the substrate base 124, respectively.

A light source 110 is mounted on the circuit pattern region 121 of the substrate base 124. In the circuit pattern region 121, a circuit for driving the light source 110 is mounted.

Although not shown separately in FIGS. 1 and 2, the printed circuit board 120 includes an electrode pad (not shown) formed to be connected to the second metal layer 222 on the circuit pattern region 121 of the substrate base 124, ). The electrode pad (not shown) is bonded to the light source 110.

The printed circuit board 120 is connected to the bottom cover (not shown) of the display device in a state in which the circuit pattern area 121 and the heat radiation area 122 are bent with the drill area 123 as an axis. do.

In the circuit pattern region 121 in which the light source 110 and the electrode pad (not shown) to be bonded thereto are arranged so that the center of the light source 110 can be positioned corresponding to the center of the thickness of the light guide plate 130 The position is adjusted according to the thickness of the light guide plate 130.

The electrode pad (not shown) and the light source 110 are arranged on one side of the edge of the circuit pattern region 121, spaced apart from the drilled region 123, so that the light source 110 faces the side surface of the light guide plate 130. [ As shown in FIG. That is, the light source 110 and the electrode pad (not shown) are disposed in the circuit pattern region 121 along the direction parallel to the drill region 123, and the drill region 123 As shown in Fig.

 When the printed circuit board 120 is in a state in which the circuit pattern region 121 and the heat radiation region 122 are folded with each other so as to be engaged with the bottom cover (not shown) of the display device, the light source 110 The closer to one side of the edge of the circuit pattern area 121 from the drilled area 123 than to the heat radiation area 122, the closer to the side center of the relatively thick light guide plate 130 .

At least one screw hole 125 formed through the substrate base 124 may be formed in the heat radiation region 122 of the substrate base 124. At this time, the screw hole 125 may be disposed at one side edge of the heat radiation region 122 of the printed circuit board 120. Although not shown in FIG. 1, the screw holes 125 may be disposed anywhere in the heat radiation region 122, not only on one side edge of the heat radiation region 122 of the printed circuit board 120.

At least one screw hole 125 may be used to couple the printed circuit board 120 to the bottom cover (not shown) of the display device. That is, the printed circuit board 120 can be fixed to the bottom cover (not shown) of the display device by inserting a screw (not shown) passing through the bottom cover (not shown) of the display device into the screw hole 125 . Thus, the printed circuit board 120 can directly contact the bottom cover without the adhesive material to improve the heat radiation efficiency.

The drill region 123 of the substrate base 124 is a groove for bending between the circuit pattern region 121 and the heat radiation region 122.

The printed circuit board 120 is bonded to the bottom cover (not shown) of the display device in a state where the circuit pattern region 121 is bent with respect to the heat radiation region 122. As described above,

When the stress for bending the circuit pattern region 121 and the heat radiation region 122 is applied to the drill region 123 of the substrate base 124, the drill region 123 is compressed while being folded.

The drill region 123 of the substrate base 124 is formed to be thinner than the circuit pattern region 121 and the heat radiation region 122. [ By doing so, it is possible to prevent the substrate base 124 from being cleaved by the stress that bends the drilled region 123 of the substrate base 124.

At least one through hole 126 formed through the substrate base 124 and spaced apart from each other may be formed in the drilled region 123 of the substrate base 124.

The drill region 123 of the substrate base 124 is compressed by the bending stress between the circuit pattern region 121 and the heat radiation region 122 and is supplemented by the through hole 126, The length of the drill region 123 can be prevented from being extended by being pushed longer than the pattern region 121 and the heat radiation region 122.

As shown in FIG. 4, the circuit pattern region 121 of the printed circuit board 120 has a plurality of layers stacked on the substrate base 124 for heat radiation and circuit formation.

That is, the printed circuit board 120 includes a first insulating layer 211 formed on the circuit pattern region 121 of the substrate base 124, a first metal layer 221 formed on the first insulating layer 211, A second insulating layer 212 formed on the first metal layer 221, a second metal layer 222 formed on the second insulating layer 212, and an ink layer (not shown) formed on the second metal layer 222 230, and a protective layer 240 formed on the ink layer 230.

The substrate base 124 may be formed of a conductive or insulating material. The substrate base 124 may be formed of a flexible material. In this case, the printed circuit board 120 is implemented as a flexible printed circuit board (FPCB). Illustratively, the substrate base 124 may comprise Al.

The first and second insulating layers 211 and 212 may be formed of an insulating material, particularly Pre-Plug (P / P).

The first metal layer 221 may be formed of a metal material known to have excellent heat dissipation. Illustratively, the first metal layer 221 may be a multilayer or alloy comprising Cu or Al, or at least one of them.

The second metal layer 222 may be formed of a metal material known to have excellent conductivity. Illustratively, the first metal layer 221 can be Cu, or a multilayer or alloy comprising it.

The second metal layer 222 is patterned and formed in the circuit pattern region 121 of the substrate base 124 in a circuit pattern for driving the light source 110 (FIGS. 1 and 2).

The first metal layer 221 is formed to have a thickness larger than that of the second metal layer 222 to improve the heat dissipation characteristics. In particular, the thickness of the first metal layer 221 may be at least twice the thickness of the second metal layer 222.

The ink layer 230 protects the circuit pattern formed of the patterned second metal layer 222.

The protective layer 240 is for protecting the circuit pattern formed of the patterned second metal layer 222 from external (e.g., external force, dust, static electricity, etc.).

On the other hand, the back surface of the substrate base 124 may be covered with a protective film 251 and protected from the outside. In this case, the threaded hole 125 and the through hole 126 may be formed through the protective film 251 further.

As described above, the printed circuit board 120 according to one embodiment of the present invention includes the circuit pattern region 121 and the heat dissipation region 122 integrated through the drill region 123. The printed circuit board 120 is engaged with the bottom cover (not shown) of the display device in a state in which the drilled area 123 is bent to bend the circuit pattern area 121 and the heat radiation area 122. As a result, the surface area of the heat radiation region 122 is increased regardless of the size of the space in which the circuit pattern region 121 is to be arranged, because the circuit pattern region 121 and the heat radiation region 122 are not arranged in a space on an axis parallel to each other. . As a result, the heat radiation characteristics of the printed circuit board 120 and the backlight unit 100 including the printed circuit board 120 can be improved.

Since the printed circuit board 120 includes the first metal layer 221 having a thickness larger than that of the second metal layer 222 separately from the second metal layer 222 serving as the circuit pattern, .

The drilled region 123 is formed to be thinner than the circuit pattern region 121 and the heat dissipation region 122 and includes at least one through hole 126 so that the circuit pattern region 121 and the heat dissipation region 122 The drill region 123 can be prevented from being split and extended. Thus, the yield of the printed circuit board 120 can be improved.

It will be understood by those of ordinary skill in the art that the foregoing description of the embodiments is for illustrative purposes and that those skilled in the art can easily modify the invention without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention.

100: backlight unit 110: light source
120: printed circuit board 121: circuit pattern area
122: heat radiating area 123: drill area
124: substrate base 125: screw hole
126: through hole 130: reflective sheet
140: light guide plate 150: optical sheet
211, 212: first and second insulating layers
221, 222: first and second metal layers

Claims (12)

A circuit pattern region for mounting the light source;
A heat radiation region for radiating heat generated from the light source; And
A drill region between the circuit pattern region and the heat dissipation region,
Wherein the drill region is thinner than the circuit pattern region and the heat radiation region,
Wherein the light source is disposed closer to one side of the edge of the circuit pattern area than the drill area. A circuit pattern region for mounting the light source;
A heat radiation region for radiating heat generated from the light source; And
A drill region between the circuit pattern region and the heat dissipation region,
Wherein the drill region is thinner than the circuit pattern region and the heat radiation region,
And at least one through hole formed through the drill region and spaced apart from each other. 3. The method according to claim 1 or 2,
And at least one screw hole in which the heat radiation region is formed. 3. The method according to claim 1 or 2,
A first insulating layer formed on the circuit pattern region;
A first metal layer formed on the first insulating layer;
A second insulating layer formed on the first metal layer; And
And a second metal layer formed on the second insulating layer,
And the second metal layer includes a circuit pattern electrically connected to the light source. 5. The method of claim 4,
Wherein the first metal layer is thicker than the second metal layer. Light source;
A printed circuit board including a circuit pattern region for mounting the light source, a heat radiation region for radiating heat generated from the light source, and a drill region between the circuit pattern region and the heat radiation region; And
And a light guide plate including a side surface facing the light source mounted on the circuit pattern region,
Wherein the drill region is thinner than the circuit pattern region and the heat radiation region,
Wherein the light source is disposed closer to one side of the edge of the circuit pattern area than the drill area so as to be positioned in correspondence with the center axis of the light guide plate. Light source;
A printed circuit board including a circuit pattern region for mounting the light source, a heat radiation region for radiating heat generated from the light source, and a drill region between the circuit pattern region and the heat radiation region; And
And a light guide plate including a side surface facing the light source mounted on the circuit pattern region,
Wherein the drill region is thinner than the circuit pattern region and the heat radiation region,
Wherein the printed circuit board is formed through the drill region and includes at least one through hole spaced apart from each other. 8. The method according to claim 6 or 7,
Wherein the printed circuit board has a shape in which the circuit pattern region and the heat dissipation region are bent together with the drill region as an axis. 8. The method according to claim 6 or 7,
Wherein the printed circuit board further comprises at least one screw hole formed through the heat radiation region. 8. The method according to claim 6 or 7,
The printed circuit board
A first insulating layer formed on the circuit pattern region;
A first metal layer formed on the first insulating layer;
A second insulating layer formed on the first metal layer; And
And a second metal layer formed on the second insulating layer,
The second metal layer includes a circuit pattern electrically connected to the light source,
Wherein the first metal layer is thicker than the second metal layer.
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