KR20160022994A - Liquid crystal display device - Google Patents

Abstract

The present invention provides a liquid crystal display device, simplifying a process of assembling a backlight unit to reduce a manufacturing cost and improving productivity. According to the present invention, the liquid crystal display device includes a backlight unit, wherein a printed circuit pattern is formed on a reflector member disposed on a cover bottom inner surface and a light source module is mounted on the printed circuit pattern. Therefore, a structure and a manufacturing process of the liquid crystal display device can be simplified, and a mural defect of a screen can be eliminated.

Description

[0001] LIQUID CRYSTAL DISPLAY DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device including a light source module having a simple structure.

When a voltage is applied to a specific molecular arrangement of a liquid crystal, the liquid crystal display device is converted into another molecular arrangement, and changes in optical properties such as birefringence, optical rotation, dichroism, and light scattering characteristics of the liquid crystal cell that emits light by such molecular arrangement, And is a display device that displays information using the modulation of light by the liquid crystal cell.

 In such a liquid crystal display device, a backlight unit is provided below the liquid crystal display panel, and an image is displayed by the light emitted from the backlight unit.

1 is a cross-sectional view illustrating a light source module of a backlight unit applied to a conventional liquid crystal display device.

1, a light source module 40 of a backlight unit applied to a conventional liquid crystal display includes a light source package 48, a circular reflector 42, and a light diffusion lens 41.

The light source package 48 may include a chip-type light emitting diode (LED), for example.

The circular reflector 42 surrounds the light source package 48 in the form of a circular plate and reflects light emitted from the light source package 48 upward.

The light diffusing lens 41 is combined with the circular reflector 42 to cover the light source package 48. The light diffusion lens (41) diffuses the light emitted from the light source package (48).

A plurality of printed circuit boards (PCBs) 35 are arranged on the inner surface of the cover bottom 30 of the backlight unit storing the light source module 40 as described above at regular intervals. The light source module 40 is mounted on each of the plurality of printed circuit boards 35 with heat.

On the cover bottom 30, a reflector sheet 60 in which a plurality of light source modules 40 are passed through is provided.

On the reflective sheet 60, a diffusion plate and an optical sheet portion, which are spaced apart from the plurality of light source modules 40 at a predetermined interval, are disposed, though not shown in the figure.

The backlight unit applied to the conventional liquid crystal display device as described above is constructed by assembling the mechanisms and optical components such as the cover bottom 30, the printed circuit board 35, the light source module 40, the reflective sheet 60, very complicated. Particularly, since the light source module 40 is accurately positioned in the through hole of the reflection sheet 60, accuracy in the backlight unit assembly process is further required. Therefore, the manufacturing cost of the liquid crystal display device can be increased, and the productivity of the product can be lowered.

When the central axis of the light source package 48 and the light diffusion lens 41 are deformed due to misalignment generated in the process of assembling the light source module 40, 40 may be biased toward one side. This causes defective Mura on the screen, which may degrade image quality.

Further, the optical gap between the diffusion sheet and the light source module is small, the number of the light source modules can be increased, and the production cost can be increased.

It is a technical object of the present invention to provide a liquid crystal display device which can simplify the assembling process of the backlight unit, reduce the manufacturing cost, and improve the productivity of the product.

Another object of the present invention is to provide a liquid crystal display device which can simplify a light source module and improve a defective Mura on a screen.

Other features and advantages of the invention will be set forth in the description which follows, or may be learned by those skilled in the art from the description and the claims.

A liquid crystal display device according to the present invention includes a cover bottom, a reflective member disposed on the cover bottom, the printed circuit pattern being formed, a plurality of light source modules mounted on the reflective member, A diffusion plate disposed on an upper end of the reflection member, an optical sheet unit disposed on the diffusion plate, and a liquid crystal display unit disposed on the upper end of the optical sheet unit, the liquid crystal display being formed of a lower substrate and an upper substrate, Panel.

According to the present invention, the printed circuit pattern is formed on the reflective member disposed on the inner surface of the cover bottom, and the light source module is mounted on the printed circuit pattern, so that the structure and manufacturing process of the liquid crystal display device can be simplified.

In addition, it is possible to prevent the light from being biased due to the misalignment occurring when the light source module is assembled, and thus the defective mura of the liquid crystal display device can be improved.

Further, according to the simplification of the structure of the light source module, the optical gap between the diffusion sheet and the light source module can be increased. Accordingly, the number of the light source modules can be reduced and the production cost can be reduced.

1 is a cross-sectional view illustrating a light source module of a backlight unit applied to a conventional liquid crystal display device.
2 is an exploded perspective view of a liquid crystal display device to which a backlight unit according to the present invention is applied.
3 is a cross-sectional view showing a cross section taken along the line I-I of the liquid crystal display of FIG. 2;
FIG. 4 is an exemplary view illustrating a light source module applied to a liquid crystal display device according to the present invention; FIG.
FIG. 5 is a cross-sectional view showing a section of the light source module of FIG. 4 taken along the II-II direction;

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail. In the case where the word 'includes', 'having', 'done', etc. are used in this specification, other parts can be added unless '~ only' is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

In the case of a description of a temporal relationship, for example, if the temporal relationship is described by 'after', 'after', 'after', 'before', etc., May not be continuous unless they are not used.

The first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, and technically various interlocking and driving are possible, and that the embodiments may be practiced independently of each other, It is possible.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is an exploded perspective view of a liquid crystal display device to which a backlight unit according to the present invention is applied, and FIG. 3 is a cross-sectional view illustrating a cross section taken along the line I-I of FIG.

2 and 3, a liquid crystal display device according to the present invention includes a cover bottom 110, a reflective member 120 disposed on the cover bottom 110 and having a printed circuit pattern 125 formed thereon, A plurality of light source modules 130 mounted on the reflective member 120, a diffusion plate 140 supported by the cover bottom 110 and disposed at an upper end of the reflective member 120, An optical sheet unit 150 disposed on the plate 140 and a lower substrate 175 and an upper substrate 176 disposed on the upper side of the optical sheet unit 150 and facing each other with a liquid crystal layer interposed therebetween And a liquid crystal display panel 170.

The cover bottom 110 accommodates the plurality of light source modules 130 and supports the diffusion plate 140, the optical sheet unit 150, the guide panel 160, and the liquid crystal display panel 170.

The cover bottom 110 includes a bottom support portion 111, an inclined portion 112, and an upper support portion 113. The bottom supporting part 111 is formed to face the remaining part except for the edge part of the liquid crystal display panel 170. The inclined portion 112 is bent to have a predetermined height from each side surface of the bottom support portion 111 to form a storage space on the bottom support portion 111. The upper support portion 113 is bent from the upper portion of the inclined portion 112 to support the lower edge portion of the liquid crystal display panel 170 so as to be parallel to the bottom support portion 111.

A reflective member 120 is attached to the upper surface of the bottom support portion 111 and the inclined portion 112 of the cover bottom 130. The reflective member 120 reflects light emitted from the plurality of light source modules 130 toward the liquid crystal display panel 170.

Although not shown in the drawing, a plurality of reflection patterns having different sizes and intervals may be formed on the reflective member 120. The light emitted from the light source modules 130 travels toward the liquid crystal display panel 170 by the reflection patterns.

The reflective member 120 may be made of a polyester (PET) film or the like, but it is not limited thereto, and may be a plate having a plurality of reflective patterns. In addition, the reflective member 120 may be formed in a multi-layer structure in which a reflective sheet in film form is attached on a plastic plate.

A plurality of printed circuit patterns 125 are formed on the reflective member 120 as described above. The printed circuit pattern 125 is formed on a substrate (for example, a reflective member) by a photolithography process in which a thin copper plate is attached and then a fine pattern is formed using photoresist (PR) . However, the present invention is not limited thereto, and may be formed by a silk screen or imprinting.

A backlight driving signal line and a connector are formed on the printed circuit pattern 125. The printed circuit pattern 125 for a light source is connected to an external backlight driver through a connector.

A plurality of light source modules 130 are mounted on a plurality of printed circuit patterns 125 formed on the reflective member 120 using Surface Mount Technology (SMT).

The surface mounting technology is a technique for mounting various electronic components (semiconductors, diodes, etc.) on each of a plurality of printed circuit boards fabricated through a base substrate, and a process in which such a technology is performed is called a surface mounting process (SMT process).

Each of the plurality of light source modules 130 is disposed at a predetermined distance from the bottom support portion 111 of the cover bottom 110 to irradiate the light to the diffusion plate 140.

Each of the plurality of light source modules 130 comprises a light source package composed of a light source and a first mold for protecting the light source, and a second mold covering an upper opening of the light source package.

That is, each of the plurality of light source modules 130 may include an electrode portion having terminals connected to the printed circuit pattern 125, a light source disposed on the electrode portion, A first mold surrounding the electrode portion and the light source, and a second mold covering an upper opening of the first mold.

In this case, chip-type light emitting diodes (hereinafter, simply referred to as LEDs), which are advantageous in terms of energy saving, environment-friendly, and high response speed, .

However, the present invention is not limited thereto, and the light source may include a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), and an external electrode fluorescent lamp (EEFL) May be used.

A second mold is formed on the light source package so as to cover the upper portion of the light source package. The second mold diffuses the light emitted from the light source package to disperse the luminance of the central portion of the light source module 130, thereby preventing hot spots and increasing the light emission area.

In this case, the second mold may have a hemispherical shape, a hemispherical shape with a central concave, and the like, but is not limited thereto, and may be formed to have a shape capable of diffusing light and covering an upper portion of the light source package.

Each of the plurality of light source modules 130 is mounted on the printed circuit pattern 125 and is electrically connected to the backlight driving unit, thereby emitting light by the backlight driving signal supplied from the backlight driving unit.

As described above, the printed circuit pattern 125 is formed on the reflective member 120 disposed on the inner surface of the cover bottom 110, and the light source module 130 is mounted on the printed circuit pattern 125, The structure of the display device and the manufacturing process can be simplified.

In addition, since a separate lens and a reflector are not consumed, it is possible to prevent the light from being biased due to mis-alignment caused when the light source module 130 is assembled. Therefore, the defective Mura of the liquid crystal display device can be improved.

In addition, according to the simplification of the structure of the light source module, the optical gap between the diffusion sheet and the light source module can be increased to reduce the number of the light source modules, thereby reducing the production cost.

Each of the plurality of light source modules 130 will be described in detail below with reference to FIGS. 4 and 5. FIG.

The diffusion plate 140 is formed in a flat plate shape having a predetermined thickness and covers the front surface of the cover bottom 110 and is disposed on the cover bottom 110. The diffusion plate 140 is spaced apart from the light source module 130 by a predetermined distance A. The distance A between the light source module 130 and the diffusion plate 140 is defined as an optical gap (OG). This is an interval required for the light emitted from each light source to diffuse toward the liquid crystal display panel 170.

The diffusion plate 140 diffuses the light emitted from each of the plurality of light source modules 130 and advances the light toward the liquid crystal display panel 170. The diffusion plate 140 is fixed by a guide panel 160.

The optical sheet unit 150 is disposed on the diffusion plate 140 and improves the luminance characteristics of light incident from the diffusion plate 140 to irradiate the liquid crystal display panel 170.

Each of the optical sheets 151, 152, and 153 included in the optical sheet unit 150 may be any one of a prism sheet, a lenticular lens sheet, and a microlens sheet.

The prism sheet may include a plurality of prism patterns formed in parallel to each other so as to have a triangular cross section, and the mountain portion and the valley portion of the prism pattern may be rounded with a certain grain.

The lenticular lens sheet may include a plurality of lenticular lens patterns formed in parallel so as to have a semicircular or semi-elliptical cross section having a predetermined curvature.

The microlens sheet may include a plurality of microlens patterns formed at a constant height so as to have a semicircular or semielliptical shape.

The optical sheet unit 150 performs a function of condensing light and diffusing the light toward the liquid crystal display panel 170 so that the brightness of the liquid crystal display panel 170 can be increased. The optical sheet unit 150 may further include a protective sheet for protecting the optical sheets 151, 152, and 153.

A liquid crystal display panel 170 is disposed on an upper portion of the optical sheet unit 150. The liquid crystal display panel 170 includes a lower substrate 175 and an upper substrate 176 bonded to each other with a liquid crystal layer (not shown) therebetween, a lower polarizing film 171 attached to the rear surface of the lower substrate 175, And an upper polarizing film 172 attached to the front surface of the upper substrate 176. [

Although not shown in the drawing, pixels are formed in the lower substrate 175 at every intersection of the gate lines and the data lines. The pixel includes a thin film transistor (Thin Film Transistor), a common electrode, and a pixel electrode.

The thin film transistors serve as switching for transferring and controlling an electric signal to each pixel. A common voltage for driving the liquid crystal is applied to the common electrode. The pixel electrode is formed on a protective film covering the common electrode, and is connected to the thin film transistor.

The lower substrate 175 controls the light transmittance of the liquid crystal layer by forming an electric field corresponding to a difference voltage between a data voltage and a common voltage applied to each pixel. A pad portion including signal application pads connected to a plurality of data lines is formed at an edge of the lower substrate 175.

The upper substrate 176 includes a black matrix (BM) and a color filter. In the color filter, red (R), green (G), and blue (B) patterns are formed. The black matrix is disposed between the R, G, and B patterns of the color filter, respectively. A column spacer (CS) may be formed on the upper substrate 176 to maintain a cell gap between the upper substrate 176 and the lower substrate 175.

The upper substrate 176 is formed to have a size smaller than that of the lower substrate 175 to open a pad portion of the lower substrate 175 with a liquid crystal layer (not shown) therebetween, Respectively.

The specific configuration of the lower substrate 175 and the upper substrate 176 may be a driving mode of the liquid crystal layer, for example, a TN (Twisted Nematic) mode, VA (Vertical Alignment) And a Fringe field switching (FFS) mode.

The lower polarizing film 171 is attached to a lower surface of the lower substrate 175 to polarize light incident on the lower substrate 175. The upper polarizing film 172 is attached to the front surface of the upper substrate 176 to polarize the light emitted to the outside through the upper substrate 176.

The lower polarizing film 171 and the upper polarizing film 172 have different polarizing functions through a stretching process in directions opposite to each other and have contraction forces in directions opposite to each other in accordance with stretching. Each of the lower polarizing film 171 and the upper polarizing film 172 is attached to the lower substrate 175 and the upper substrate 176 so that the contracting forces of the lower polarizing film 171 and the upper polarizing film 172 respectively cancel each other So that the liquid crystal display panel 170 does not bend upward or downward, but forms a flat state.

The guide panel 160 couples the edge portion of the liquid crystal display panel 170 to the upper support portion 113 of the cover bottom 110. The guide panel 160 may be a photo-curing adhesive, a thermosetting adhesive, a double-sided tape, or a double-sided adhesive pad.

The top case 180 is coupled to the guide panel 160 to fix the liquid crystal display panel 170 supported by the guide panel 160. The top case 180 is coupled to the cover bottom 110 according to a side coupling method using a fastening member such as a screw or a hook so as to be coupled to the front surface of the liquid crystal display panel 170, The edge portion and the guide panel 160 are prevented from being exposed to the outside of the liquid crystal display device.

FIG. 4 is an exemplary view illustrating a light source module applied to a liquid crystal display device according to the present invention, and FIG. 5 is a cross-sectional view illustrating a light source module of FIG. 4 taken along a line II-II.

As shown in FIG. 5, a plurality of printed circuit patterns 125 are formed on the reflective member 120. The printed circuit pattern 125 is not clearly shown in FIG. 4, but may be connected to terminals of the light source module 130, which will be described later with reference to FIG. 5, (Not shown).

In this case, the reflection member 120 may be made of a polyester (PET) film or the like, but it is not limited thereto and may be formed in a plate form. In addition, the reflective member 120 may be formed in a multi-layer structure in which a reflective sheet in film form is attached on a plastic plate.

The printed circuit pattern 125 may be formed by a photolithography process of forming a fine pattern using photoresist (PR).

For example, a metal material (for example, a copper foil) to be used as the printed circuit pattern 125 is deposited on the reflective member 120. A photoresist (PR) is applied on the metal material, and a photomask on which a printed circuit pattern 125 region is patterned is placed on the photoresist. According to the pattern of the photomask, the exposed portion and the non-exposed portion are determined. The photoresist of the non-exposed portion is developed and the metal material is etched to form a printed circuit pattern 125. The exposed portion is exposed to light, and the unexposed portion is not exposed to light. Can be formed. However, the present invention is not limited thereto, and the printed circuit pattern 125 may be formed by a method such as a silk screen or imprinting.

4 and 5, a plurality of printed circuit patterns 125 formed on the reflective member 120 are connected to the light source module 130 using surface mount technology (SMT) Respectively.

Each of the plurality of light source modules 130 includes a light source package 135 including a light source 133 and a second mold 132 covering an upper opening of the light source package 135.

The light source package 135 includes an electrode unit (not shown) having terminals connected to the printed circuit pattern 125 formed on the reflective member 120, a light source 133 disposed on the electrode unit, And a first mold 131 surrounding the electrode part and the light source 133.

The second mold 132 is formed to cover the upper first mold 131 of the light source package 135.

The electrode unit (not shown) may include a lead frame, a first electrode, and a second electrode (not shown). The lead frame supports the light source 133 and receives heat generated from the light source 133 and discharges the light to the outside.

The first electrode and the second electrode of the electrode unit (not shown) are connected to the printed circuit pattern 125 to apply the first power and the second power to the light source 133. The first power source and the second power source may be a plus electrode and a minus electrode.

The light source 133 generates light and emits light by a power source applied from the electrode unit (not shown).

As the light source 133, a light emitting diode (LED) (hereinafter, simply referred to as an LED) having advantages of energy saving effect, environment friendly, and high response speed can be used.

However, the present invention is not limited thereto, and the light source may include a cold cathode fluorescent lamp (CCFL), a hot cathode fluorescent lamp (HCFL), and an external electrode fluorescent lamp (EEFL) May be used.

The first mold 131 protects the light source 133 from the outside. A lead frame is mounted on the inner center of the first mold 131, and a light source 133 is seated on the top of the lead frame. The first mold 131 may be formed of PPA (polyphthalamide) or silicon.

A second mold 132 is formed on the light source package 135 to cover the upper portion of the light source package 135. More specifically, the second mold 132 is formed on the first mold 131 of the light source package 1350 and surrounds the light source 133.

The second mold 132 diffuses the light emitted from the light source package 135 to disperse the luminance of the central portion of the light source module 130 to prevent hot spots and to increase the light emission area do.

In this case, the second mold 132 may have a hemispherical shape, a hemispherical shape having a concave central portion, and the like, but is not limited thereto and may be formed to have a shape capable of diffusing light. In addition, the second mold 132 may be formed of the same material as the first mold 131.

As described above, since the plurality of light source modules 130 are formed, it is possible to prevent the light from being biased due to misalignment, and accordingly, the defective mura of the liquid crystal display device Can be improved.

Each of the plurality of light source modules 130 is mounted on the printed circuit pattern 125 and is electrically connected to the backlight driving signal line, thereby emitting light by the backlight driving signal supplied from the backlight driving signal line.

The interval D between the plurality of light source modules 130 may be defined as a pitch between the center portions of the adjacent light source packages 135. The interval D may be defined by a luminance of the liquid crystal display panel 170 (OG) between the top surface of the printed circuit pattern 125 and the diffusion sheet 140 so that the entire surface of the printed circuit pattern 125 is uniform over the entire area. The optical gap OG is defined as an interval required for light emitted from each of the plurality of light source modules 130 to diffuse.

As described above, the printed circuit pattern 125 is formed on the reflective member 120 disposed on the inner surface of the cover bottom 110, and the light source module 130 is mounted on the printed circuit pattern 125, The structure of the display device and the manufacturing process can be simplified.

In addition, according to the simplification of the structure of the light source module, the optical gap between the diffusion sheet and the light source module can be increased to reduce the number of the light source modules, thereby reducing the production cost.

It will be understood by those skilled in the art that the present invention may be embodied in other specific forms 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. 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 are to be construed as being included within the scope of the present invention do.

110: cover bottom 120: reflective member
130: light source module 140: diffusion plate
170: liquid crystal display panel

Claims (6)

Cover bottom;
A reflective member disposed on the cover bottom and having a printed circuit pattern formed thereon;
A plurality of light source modules mounted on the reflective member;
A diffusion plate supported by the cover bottom, the diffusion plate being disposed at an upper end of the reflection member;
An optical sheet portion disposed on the diffuser plate; And
And a liquid crystal display panel disposed on an upper end of the optical sheet unit, the liquid crystal display panel being formed of a lower substrate and an upper substrate facing each other with a liquid crystal layer interposed therebetween. The method according to claim 1,
Wherein each of the plurality of light source modules comprises:
An electrode part formed with terminals connected to the printed circuit pattern;
A light source disposed on the electrode portion;
A first mold surrounding the electrode portion and the light source; And
And a second mold covering an upper opening of the first mold. The method according to claim 1,
Wherein each of the plurality of light source modules comprises:
And is mounted on the printed circuit pattern on the reflective member, and is electrically connected to the backlight driver. 3. The method of claim 2,
Wherein the second mold is hemispherical and the central portion is concave. 3. The method of claim 2,
Wherein the first mold and the second mold are made of the same material. The method according to claim 1,
Wherein the reflective member comprises a film and a plate on which a reflective pattern is formed.

Images