KR102151059B1 - liquid crystal display device - Google Patents

Abstract

The present invention, a liquid crystal panel; A backlight unit positioned below the liquid crystal panel and including a reflector, a light guide plate, and a plurality of light sources; A support main surrounding an edge of the backlight unit; The support main includes a cover top and is assembled and fastened, the PCB on which the plurality of light sources are mounted, and the plurality of light sources are formed to be spaced apart from each other, and the plurality of light sources also guide light emitted from the light source to the A plurality of first portions formed in correspondence with the light guide plate so as to be incident on the light guide plate, and fastened to the upper portion of the light source to be positioned between the PCB and the light guide plate, and the edge of the light source and the light guide plate perpendicular to the first portion There is provided a liquid crystal display device in which a partial housing including a second portion that can be partially covered is further formed.

Description

Liquid crystal display device

The present invention relates to a liquid crystal display device using an LED as a light source, and in particular, to a liquid crystal display device capable of preventing a light source from being pressed by expansion of a light guide plate as well as preventing light loss.

The liquid crystal display device (LCD), which is advantageous for displaying moving images and has a high contrast ratio, is actively used in TVs and monitors. The optical anisotropy and polarization of liquid crystals The principle of image implementation is shown.

Such a liquid crystal display device uses a liquid crystal panel bonded by interposing a liquid crystal layer between two parallel substrates as an essential component, and a difference in transmittance is realized by changing the alignment direction of liquid crystal molecules by an electric field in the liquid crystal panel. do.

However, since the liquid crystal panel does not have its own light emitting element, a separate light source is required to display the difference in transmittance as an image, and for this purpose, a backlight with a light source is disposed on the back of the liquid crystal panel.

Here, as a light source of the backlight unit, a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp, and a light emitting diode (LED, hereinafter referred to as LED) are used. .

Among them, LEDs, in particular, have features such as small size, low power consumption, and high reliability, and are being widely used as a display light source.

1 is a cross-sectional view of a backlight of a liquid crystal display device using a general LED as a light source.

As shown, a general backlight is composed of a support main (1), a cover top (2), a light source (5), a light guide plate (4), and a plurality of optical sheets (3).

The backlight unit includes a plurality of light sources 5 arranged along the height direction of at least one edge of the support main 1, a white or silver reflecting plate 7 mounted on the cover butt 2, and such a reflecting plate 7 It includes a light guide plate 4 mounted thereon and a plurality of optical sheets 3 interposed thereon. In addition, an LED housing (not shown in the drawing) is further configured to be formed under the reflector 7 to emit heat generated from the light source 5 to the outside.

At this time, a plurality of light sources 5 emitting white light are configured on one side of the light guide plate 4, and are mounted on a printed circuit board (PCB) 6, hereinafter, referred to as a PCB.

Such a liquid crystal panel (not shown) and the backlight unit have a top cover (not shown) surrounding the upper edge of the liquid crystal panel (not shown) and a cover covering the back of the backlight unit with the edge surrounded by a rectangular frame-shaped support main (1). The buttum (2) is combined in the front and rear, respectively, and integrated through the support main (1).

As shown, a plurality of light sources 5 are arranged along one side of the light guide plate 4 of the modularized liquid crystal display module, and the plurality of light sources 5 are mounted on the PCB 6. Here, as the PCB 6, a metal core printed circuit board (MCPCB) formed of metal may be used to dissipate high temperature heat generated from the plurality of light sources 5 to the outside.

The plurality of light sources 5 are fixed in position by bonding or the like, and the emitted light faces the light guide plate 4 to face the light-incident surface. For this purpose, one edge of the cover bottom 2 is bent upward to form a side surface. .

At this time, in order to discharge the high-temperature heat generated from the plurality of light source LEDs 5 to the outside, the lower surface of the PCB 6 and the cover top 2 formed of a metal material are in contact with each other. That is, heat generated from the plurality of light sources 5 is radiated to the outside through the PCB 6 and the cover top 2.

Such a conventional liquid crystal display device has the following problems.

First, the light guide plate 4 is formed of resin, which is a material weak to heat. Accordingly, there is a problem that the light guide plate is expanded by heat at a high temperature, and the expanded light guide plate presses the light source 5, and the light source 2 and the light guide plate are deformed.

.

In addition, in order to efficiently incident the light emitted from the light source 5 to the light guide plate 4, the light emitting surface of the light source 5 and the incident surface of the light guide plate 4 must correspond to each other, and a certain alignment must be aligned.

However, due to the deformation of the light guide plate 4 and the light source 5, the light guide plate 4 and the light source 5 are tilted to create a gap, and all the light emitted from the light source 5 through the generated gap is the light guide plate 4 There is a problem of light leakage that cannot be incident to and leaks out.

The present invention provides a liquid crystal display device capable of preventing not only loss of light but also damage to a light source due to expansion of a light guide plate.

The present invention, a liquid crystal panel; A backlight unit positioned below the liquid crystal panel and including a reflector, a light guide plate, and a plurality of light sources; A support main surrounding an edge of the backlight unit; The support main and the cover buttoum is assembled and fastened, the PCB on which the plurality of light sources are mounted, and the plurality of light sources are formed to be spaced apart from each other, and the plurality of light sources also guide the light emitted from the light source to the A plurality of first portions formed in correspondence with the light guide plate so as to be incident on the light guide plate, and fastened to the upper portion of the light source to be positioned between the PCB and the light guide plate, and the edge of the light source and the light guide plate perpendicular to the first portion There is provided a liquid crystal display device in which a partial housing including a second portion that can be partially covered is further formed.

The partial housing is formed in the form of'┍ ', and the plurality of first portions are formed by being fastened between the plurality of light sources.

The first portion is formed to protrude toward the light guide plate rather than the light source to prevent the light source from being pressed due to expansion of the light guide plate, and the partial housing is made of a material having a thermal expansion coefficient greater than that of resin.

The width of the first portion is formed to be smaller than the interval between the light sources.

An inner side of the partial housing is a reflective layer that reflects light or an absorbing layer that absorbs light. In addition, the partial housing is further assembled and fastened with the cover butt, and the liquid crystal display includes a liquid crystal display having a curved shape.

The present invention has an effect of forming a partial housing between the light source and the light guide plate to prevent pressure on the light source while the light guide plate expands due to heat.

In addition, the present invention has the effect of solving the light leakage generated from the gap generated when the light guide plate and the light source are misaligned due to the second portion formed on the upper portion of the light source and the partial housing.

In addition, the present invention has an effect of improving luminance and image quality of a liquid crystal display because light emitted from the reflective layer formed inside the partial housing can be incident on the light guide plate again without loss.

1 is a cross-sectional view of a general liquid crystal display device.
2 is a cross-sectional view of a liquid crystal display device according to an embodiment of the present invention.
FIG. 3 is a cross-sectional view of a liquid crystal display taken along line AA' of FIG. 1;
4 is a perspective view showing a partial housing according to a second embodiment of the present invention.
5 is a perspective view showing a partial housing according to a third embodiment of the present invention.
6 is a cross-sectional view of a partial housing of the present invention

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

2 is a cross-sectional view of a liquid crystal display module according to an embodiment of the present invention.

The liquid crystal display module may include a liquid crystal panel (not shown), a backlight unit, a support main 10, a cover top 20, and a top cover (not shown).

First, although not shown, the liquid crystal panel plays a key role in image expression, and includes a first substrate and a second substrate bonded to each other with a liquid crystal layer therebetween.

In this case, a pixel is defined by crossing a plurality of gate lines and data lines on an inner surface of the first substrate called a lower substrate or an array substrate. In addition, a thin film transistor (TFT) is formed at each intersection of a plurality of gate lines and data lines to be connected to corresponding pixel electrodes.

In addition, color filters of red, green, and blue colors are formed on the inner surface of the second substrate called the upper substrate or the color filter substrate as an example corresponding to each pixel. In addition, a black matrix corresponding to non-display elements of the first substrate, such as gate lines, data lines, and thin film transistors, is provided to cover them. Here, when the liquid crystal display is driven in the vertical electric field mode, a color filter and a common electrode covering the black matrix may be further formed on the second substrate.

In addition, polarizing plates (not shown) that selectively transmit only specific light are attached to outer surfaces of the first and second substrates, respectively.

In addition, in the liquid crystal panel, a printed circuit board is connected along at least one edge through a connecting member such as a flexible circuit board or a tape carrier package (TCP).

The backlight unit, for example, is located on the rear surface of the liquid crystal panel and serves to supply light to the liquid crystal panel.

To this end, the backlight unit includes a plurality of light sources 50, a white or silver reflecting plate 170, a light guide plate 40 mounted on the reflecting plate 70, and a plurality of optical sheets 30 interposed thereon. Can include.

First, a plurality of light sources 50 are located on one side of the light guide plate 40 so as to face the light incident surface of the light guide plate 40, and these light sources 50 are mounted on the PCB 60 at regular intervals. .

At this time, the plurality of light sources 50 emit light having colors of red, green, and blue, respectively, toward the light-incident surface of the light guide plate 40, and white light due to color mixing by turning on the plurality of RGB light sources 50 at once. Can be implemented.

On the other hand, by using a light source 50 configured with a light source chip (not shown) that emits all RGB colors, white light may be implemented in each light source 50, or complete white color including a chip emitting white An emitting light source 50 may also be used.

The PCB 560 may be composed of a metal core printed circuit board (MCPCB) having a heat dissipation function. That is, by using the metal PCB 60 having a high thermal conductivity, high temperature heat generated from the light source 50 can be quickly released to the outside. In this case, when the PCB 60 is formed of MCPCB, an insulating layer (not shown) such as a polyimide resin material for electrical insulation between a metal core and a wiring pattern (not shown) may be formed. .

The light guide plate 40 provides a surface light source to the liquid crystal panel by dispersing light emitted from the light source 50. Specifically, the light emitted from the light source 50 is totally reflected several times while traveling inside the light guide plate 40. Accordingly, the light is evenly spread over a wide area of the light guide plate 40 and is incident on the liquid crystal panel as a surface light source.

In this case, the light guide plate 40 may include, for example, a pattern of a specific shape on the rear surface to supply a uniform surface light source to the liquid crystal panel. The pattern may be formed in various ways, such as an elliptical pattern, a polygon pattern, a hologram pattern, etc. to guide the light incident into the light guide plate 40. I can. Such a pattern is formed on the rear surface of the light guide plate 14 by a printing method or an injection method.

The reflecting plate 70 is located on the rear surface of the light guide plate 40 and reflects the light passing through the rear surface of the light guide plate 40 toward the liquid crystal panel, thereby improving the luminance of light.

The plurality of optical sheets 30 on the upper part of the light guide plate 40 includes a diffusion sheet and at least one light collecting sheet, and diffuses or condenses the light that has passed through the light guide plate 40 to provide a more uniform surface light source to the liquid crystal panel. Let's join.

The liquid crystal panel and the backlight unit are modularized through a top cover (not shown), a support main 10, and a cover bottom 20.

The cover bottom 20, which is a basis for assembling the entire fixture of the liquid crystal display module by mounting the liquid crystal panel and the backlight unit, is formed in a single plate-shaped horizontal plane of a square shape.

At this time, the PCB is formed at one edge of the cover buttoum 20 perpendicular to the horizontal plane. Also,

The support main 10 is fastened while surrounding the outside of the cover buttum 20.

In addition, a partial housing including the light source 50 and a second portion covering one edge of the upper portion of the light guide plate 40 so that light emitted from the light source 50 does not leak and can be efficiently incident to the light guide plate 40. 80) is formed. Through this, light emitted from the light source 50 can be concentrated in the direction of the light guide plate 40 to prevent light loss.

At this time, the partial housing 80 includes a first portion formed between the PCB 60 and the light guide plate 40 while being fastened between the plurality of light sources 50. Therefore, it is possible to prevent the light guide plate 40 from being expanded or pushed to press or press the light source 50.

The backlight unit having the above-described structure is generally referred to as a side light method, and a plurality of light sources 50 may be arranged on the PCB 60 according to the purpose. In addition, it is obvious to those skilled in the art that it is possible to further include the light source 50 in a plurality of sets, respectively, to interpose each other along both edges facing each other of the cover bottom 20.

Hereinafter, FIGS. 3 to 5 show embodiments of the liquid crystal display taken along line A-A'. With reference to FIGS. 3 to 5, the cover bottom 20 and the plurality of light sources 50 and partial housing 80 of the present invention will be described in more detail.

As shown in FIG. 3, a PCB 60 is formed at an edge of the cover bottom 20 perpendicular to the horizontal bottom, and a plurality of light sources 50 are mounted on the PCB 60.

In addition, the plurality of first portions 80b inserted between the plurality of light sources 50 and the plurality of first portions extend in a vertical direction so that the upper surface of the light source 50 and a part of the edge of the light guide plate (not shown) The partial housing 80 including the covering second portion 80a is fastened to the light source.

It may be further fixed with an adhesive between the partial housing 80 and the PCB 60.

The partial housing 80 is formed integrally with a material such as PC or metal, which is more resistant to heat than resin.

The first portion 80b and the second portion 80a are connected to each other to form a'┏' shape.

Here, the width of the first portion 80b may have a value smaller than the interval between the plurality of light sources. In addition, the thickness of the first portion 80b is larger than the thickness of the light source 50 and thus protrudes from the light source 50 toward the light guide plate 40. At this time, it is possible to prevent the light guide plate 40 from being damaged by pressing the light source 50 by being expanded or pushed by heat.

In addition, due to a portion of the edge of the light guide plate 40 and the second part 80a covering the upper surface of the light source 50, the alignment between the light guide plate 40 and the light source 50 is alleviated to prevent light leakage. Plays a role.

4 is a cross-sectional view schematically showing a light incident part according to a second embodiment of the present invention taken along line A-A'.

Hereinafter, a second embodiment of the partial housing of the present invention will be described with reference to FIG. 4.

First, descriptions of parts that are the same or similar to those of the first embodiment are omitted.

As shown in Fig. 4, in the second embodiment of the present invention, the partial housing 81 is further provided with a fastening portion 81c.

Specifically, the fastening part 81c of the partial housing 81 and the cover bottom 21 are assembled and fastened to each other. To this end, the fastening portion 81c is formed to extend vertically in the direction of the first portion 81b from the second portion 81a.

At this time, the fastening part 81c surrounds the outer surface of the cover butt 21 and is completely assembled and fastened through screws or hooks.

Through this, the partial housing 81 serves to guide the light guide plate 41 and the plurality of light sources 51 more stably by preventing the separation and flow of the cover buttum 21 and the partial housing 81 even in the event of an external impact. .

In addition, the second portion 81a of the partial housing 81 covers the upper surface of the plurality of light sources 51 and a part of the edge of the light guide plate 41 to prevent twisting, thereby preventing light leaking from the light source 51. It can be as described above. Accordingly, the first portion 81b protrudes in the direction of the light guide plate 41 rather than the light source 51 to prevent damage to the light source 51 due to expansion or push of the light guide plate as described above.

5 is a cross-sectional view schematically showing a light incident part according to a third embodiment of the present invention taken along line A-A'.

Hereinafter, descriptions of parts that are the same as those of the first and second embodiments of the third embodiment of FIG. 5 will be omitted.

As shown in Fig. 5, the first portion 81a of the partial housing 82 is fastened to one of two of the plurality of light sources 52.

Specifically, the first portion 82b is not formed between the plurality of light sources 52, but is formed between two or more light sources. Here, the partial housing 82 may further include a fastening portion that is fastened to the cover buttum 22.

Fig. 6 shows a cross-sectional view of a partial housing of the present invention.

As shown in FIG. 6, the partial housing 86 of the present invention includes a first portion 86a and a second portion 86b.

Specifically, a reflective layer 90 for reflecting light is formed on the inner surface of the partial housing 86. The reflective layer 90 reflects light emitted from the light source 50 and makes it incident on the light guide plate (40 in FIG. 2). To this end, the reflective layer 90 is formed only on the inner wall surface of the first part 86b of the partial housing 86, or is formed at the same time as the inner wall surface of the first part 86b and the second part 86a.

A reflective layer RP having high light reflection efficiency is formed on the reflective layer 90 of the partial housing 86. At this time, the reflective film RP may be formed by, for example, bonding a material used for the reflective plate (70 in FIG. 2) or coating a synthetic resin having high reflective efficiency. In addition, when the partial housing 86 is made of a metal material, it may be formed by mirror-finishing the inner surface.

Accordingly, a plurality of light sources (50 in Fig. 2) efficiently reflects light emitted from a plurality of light sources to the light guide plate (40 in Fig. 2) through the reflective layer 90 formed in the partial housing, and is emitted from the light source 50a. Guided light to enter the light guide plate without loss.

In addition, an absorbing layer 91 for absorbing light may be formed on an inner wall surface of the second portion 86a of the partial housing. Specifically, the absorption layer 91 may prevent leakage of light emitted from the light source (50 in FIG. 2) to the outside by attaching a light shielding tape, for example, a gray or black pad or double-sided tape capable of blocking light. Therefore, it may be formed by coating the gray or black light absorption layer 91 on the inner wall surface of the first part 86a to prevent light leakage due to leakage of light emitted from the light source to the outside.

The light absorbing layer 91 is a light leaking from the gap so that a gap is created when the alignment of the light guide plate (40 in FIG. 2) and a plurality of light sources (50 in FIG. 2) are misaligned to prevent a hot spot. Absorbs.

The above-described embodiment of the present invention is an example of the present invention, and can be freely modified within the scope of the spirit of the present invention. Accordingly, the present invention includes modifications of the present invention within the scope of the appended claims and equivalents thereto.

10: support main 20: cover strength
30: optical sheet 40: light guide plate
50: light source 60: PCB
70: reflector 80: partial housing
80a: second part 80b: first part
90: reflective layer 91: light absorbing layer

Claims (12)

A liquid crystal panel;
A backlight unit located under the liquid crystal panel and including a reflector, a light guide plate, a plurality of light sources, and a PCB on which the plurality of light sources are mounted;
A support main surrounding an edge of the backlight unit;
A cover butt that is assembled and fastened to the support main;
A plurality of first portions fastened to the upper portion of the light source and positioned between the PCB and the light guide plate, and a first portion perpendicular to the first portion and covering the light source and a portion of the edge of the light guide plate and extending along the length direction of the PCB. Part 2; It includes a partial housing including a fastening portion that extends from both ends of the second portion toward the bottom surface of the cover bottom to the outside of the side surface of the cover bottom to be fastened with the cover bottom,
The plurality of light sources are disposed to be spaced apart from each other, and the first portion has a thickness greater than that of the light source, so that the first portion protrudes toward the light guide plate from the light source.
The method of claim 1,
The plurality of first portions are fastened between the plurality of light sources to have a'┍ ' shape.
Liquid crystal display. delete The method of claim 1,
The partial housing is made of a material that is more resistant to heat than resin.
Liquid crystal display.
The method of claim 2,
The width of the first portion is formed to be smaller than the interval between the light sources.
The method of claim 2,
The first portion is formed in correspondence between the plurality of light sources.
delete The method of claim 1,
The inner side of the partial housing has a reflective layer that reflects light
Liquid crystal display.
The method of claim 1,
An absorbing layer for absorbing light is formed inside the second part of the partial housing.
Is a liquid crystal display.
delete The method of claim 1,
The liquid crystal display device has a curved shape.
The method of claim 1,
The first portion is formed between two or more light sources of the plurality of light sources.

Images