KR101408689B1 - Direct liquid crystal display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device, and more particularly, to a direct-type liquid crystal display device module.

A feature of the present invention is that a bar-type light guide plate is arranged in a spaced-apart area between lamps arranged in parallel in a direct-type liquid crystal display device so that light emitted to the lower side of the lamp is refracted and transmitted through a bar- And is emitted toward the liquid crystal panel.

Therefore, it is possible to realize a thin shape of the liquid crystal display device, and to prevent defects such as a lamp mura phenomenon which has occurred due to the low brightness of the spacing region between the conventional lamps. In addition, the leakage current generated between the lamp and the cover bottom can be cut off, thereby improving the efficiency of the lamp.

As a result, the luminance uniformity of the liquid crystal display device is improved, and the overall luminance is also improved.

A bar type light guide plate, a lamp mura, a liquid crystal display

Description

[0001] The present invention relates to a direct liquid crystal display device,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display device, and more particularly, to a direct-type liquid crystal display device module.

2. Description of the Related Art In recent years, the display field has rapidly developed in line with the information age. In response to this trend, a flat panel display device (FPD) having a thinness, light weight, A plasma display panel (PDP), an electroluminescence display device (ELD), and a field emission display device (FED) : CRT).

Among these, liquid crystal display devices are excellent in moving picture display and are most actively used in the fields of notebooks, monitors, and TV due to their high contrast ratios. Such liquid crystal display devices have no self-luminous elements, A light source is required.

Accordingly, a backlight unit having a lamp is provided on the back surface, and light is irradiated toward the front of the liquid crystal panel, thereby realizing an image of a brightness that can be recognized only through the backlight unit.

In general, an ordinary backlight unit is divided into an edge type and a direct type according to the arrangement structure of the lamp. The edge type has a structure in which one or a pair of lamps are disposed on one side of the light guide plate, Two or two pairs of lamps are disposed on both side portions of the light guide plate, and the direct type lamp has a structure in which several lamps are disposed under the optical sheet.

In recent years, research has been actively conducted on large-sized liquid crystal display devices with a size of 20 inches or more according to the demand of a consumer, a direct-type method of directly irradiating light toward a liquid crystal panel is more suitable for a large- Do.

1 is a cross-sectional view of a liquid crystal display device using a general direct type backlight unit.

As shown in the figure, a typical liquid crystal display device includes a liquid crystal panel 10 composed of first and second substrates 12 and 14 and a backlight unit 20 behind the liquid crystal panel 10.

Here, the backlight unit 20 includes a reflection plate 22, and a plurality of lamps 24 are arranged in parallel on a top surface of the backlight unit 20. Above the lamps 24, a diffusion plate 26 and a plurality of optical sheets 29).

The liquid crystal panel 10 and the backlight unit 20 are modularized through the top cover 40, the guide panel 30 and the cover bottom 50, that is, the edges of the liquid crystal panel 10 and the backlight unit 20 A top cover 40 covering the front edge of the liquid crystal panel 10 and a cover bottom 50 covering the back surface of the backlight unit 20 are coupled to the guide panel 30 in a front- 30).

On the other hand, in recent years, large area liquid crystal display devices have been widely used, and research on thin liquid crystal display devices has been progressing actively with a wide display area.

Therefore, in recent years, by reducing the interval d1 between the lamp 24 and the diffuser plate 26 of the backlight unit 20 and by decreasing the interval d2 between the lamp 24 and the reflector 22, An attempt has been made to provide a liquid crystal display device.

However, in order to supply a high-quality surface light source, which is the most important role of the backlight unit 20, to the liquid crystal panel 10, various optical designs are considered, one of which is a lamp 24 and a diffusion plate 26, And the distance d2 between the lamp 24 and the reflector 22 are important factors.

Therefore, when the distance d1 between the lamp 24 and the diffusion plate 26 is too small or the distance d2 between the lamp 24 and the reflection plate 22 is small, the light from the lamp 24 is strong The spacing D between adjacent lamps 24 is relatively lower than that of the region C where the lamps 24 are located.

Such a difference in brightness causes a lamp mura phenomenon such as unevenness on the display screen, which causes the display quality of the liquid crystal display device to deteriorate.

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a thin liquid crystal display device and to solve the problem of a lamp mura or the like.

Another object of the present invention is to prevent deterioration of display quality due to uneven luminance of the liquid crystal display device.

In order to achieve the above-mentioned object, the present invention provides an electronic device comprising: a cover bottom; A plurality of lamps arranged on the cover burdens and spaced apart from each other; A plurality of bar type light guide plates formed along the longitudinal direction of the lamp in the spaced spaces of the plurality of lamps; A plurality of optical sheets positioned above the plurality of lamps; The lamp includes a first upper side surface of a first bar type light guide plate and a second upper side surface of a second bar type light guide plate adjacent to the first upper side surface of the first bar type light guide plate And one half of the outer circumferential surface of the lamp is wrapped around the lamp.

And a half of the outer circumferential surface of the lamp is an outer circumferential surface facing the cover bottom about a virtual line of the lamp center portion. The bar type light guide plate includes upper and lower surfaces parallel to each other, First and second lower side surfaces bent obliquely upwardly and first and second upper side surfaces connecting the first and second lower side surfaces and the upper surface, the cross-section of the first and second upper surfaces being substantially hexagonal in cross section.

The first and second upper side surfaces are concavely rounded to surround a part of the outer circumferential surface of the lamp. The first and second upper side surfaces are inclined at a predetermined angle so as to surround a part of the outer circumferential surface of the lamp, .

In this case, the first and second lower side surfaces are coated with a reflective material, and an insulating material corresponding to the lamp is formed between the first and second lower side surfaces.

In addition, a diffusion pattern is formed on the lower surface, and both ends of the lower surface are inclined at a predetermined inclination to form a reflective jaw protruding upward toward the center of the bar type light guide plate. And a diffusion plate on the lamp.

As described above, a light guide plate of a bar type is arranged at angularly spaced areas between lamps arranged in parallel according to the present invention, and light emitted to the lower side of the lamp is guided through the bar type light guide plate to the liquid crystal panel The distance between the lamp and the reflecting plate or the distance between the lamp and the reflecting plate can be reduced. Therefore, it is possible to realize the thinness of the liquid crystal display device, It is possible to prevent defects such as a lamp mura phenomenon that has occurred due to a low temperature.

In addition, the leakage current generated between the lamp and the cover bottom can be cut off, thereby improving the efficiency of the lamp.

This has the effect of improving the luminance uniformity of the liquid crystal display device and improving the overall luminance.

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

2 is an exploded perspective view illustrating a liquid crystal display device according to an embodiment of the present invention.

As shown, the liquid crystal display comprises a liquid crystal panel 110, a backlight unit 120, a support main 130, a cover bottom 150, and a top cover 140.

First, the liquid crystal panel 110 plays a key role in image display and includes first and second substrates 112 and 114 which are bonded to each other with a liquid crystal layer interposed therebetween.

At this time, a plurality of gate lines and data lines intersect to define a pixel on the inner surface of the first substrate 112, which is usually referred to as a lower substrate or an array substrate, although not clearly shown in the drawing, And a thin film transistor (TFT) is provided at each intersection point, and is connected to the transparent pixel electrode formed in each pixel in a one-to-one correspondence manner.

On the inner surface of the second substrate 114 called an upper substrate or a color filter substrate, a color filter of red (R), green (G), and blue (B) And a black matrix for covering non-display elements such as a gate line, a data line, and a thin film transistor. In addition, a transparent common electrode covering these elements is provided.

The printed circuit boards 117a and 117b are connected to each other along at least one edge of the liquid crystal panel 110 via a connecting member 116 such as a flexible printed circuit board so that the side surfaces or the cover bottoms 140).

Although not clearly shown in the drawing, an upper and a lower alignment film (not shown) for determining the initial alignment direction of the liquid crystal are interposed between the two substrates 112 and 114 of the liquid crystal panel 110 and the liquid crystal layer A seal pattern is formed along the edges of both substrates 112 and 114 to prevent leakage of the liquid crystal layer filled therebetween.

At this time, upper and lower polarizers (not shown) are attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

A backlight unit 120 for supplying light is provided on a back surface of the liquid crystal panel 110 so that a difference in transmittance represented by the liquid crystal panel 110 is externally expressed.

The backlight unit 120 includes a reflection plate 122, a plurality of lamps 124 and a diffusion plate 126 and a plurality of optical sheets 129. The present invention is particularly applicable to a plurality of bar- (Hereinafter referred to as a bar-type light guide plate) 200.

In other words, a plurality of lamps 124 are arranged on the reflector 122 in a spaced-apart relation to each other, and a plurality of bar-type light guide plates 200 are arranged in the spaced apart areas of the lamps 124, The diffusion plate 126 and the plurality of optical sheets 129 are positioned.

In this case, the lamp 124 may be a light source such as a fluorescent lamp such as a cathode cathode fluorescent lamp or an external electrode fluorescent lamp.

And a pair of side supports 128 for fixing / supporting the plurality of lamps 124 are provided and fastened to the cover bottom 150.

At this time, in addition to fixing the lamp 124, the side support 128 maintains a constant gap between the lamp 124 and the diffusion plate 126.

The plurality of optical sheets 129 include a diffusion sheet and at least one light collecting sheet and the like and the bar type light guide plate 200 is configured to condense light emitted toward the lower side of the lamp 124 toward the liquid crystal panel 110 .

Here, the lower side of the lamp 124 is an outer circumferential surface facing the reflector 122 around a virtual horizontal line at the center of the lamp 124.

 The reflective plate 122 is disposed on the rear surface of the plurality of lamps 124 and reflects some light that is not incident on the bar type light guide plate 200 out of the light emitted to the lower side of the lamp 124, Thereby improving the luminance of the light.

Accordingly, the light emitted from the plurality of lamps 124 is processed uniformly and in a high-quality state while passing through the diffusion plate 126 and the plurality of optical sheets 129 through the direct or bar-type light guide plate 200 And is incident on the post-liquid crystal panel 110, and the liquid crystal panel 110 can display an image of high brightness only by using it.

The liquid crystal panel 110 and the backlight unit 120 are modularized through a top cover 140, a support main body 130 and a cover bottom 150. The top cover 140 is disposed on the top surface of the liquid crystal panel 110 And the front cover 140 is opened to display an image to be displayed on the liquid crystal panel 110. The liquid crystal panel 110 may be a liquid crystal display.

In addition, the cover bottom 150, which is a base for assembling the entire liquid crystal display device with the liquid crystal panel 110 and the backlight unit 120 mounted thereon, is formed into a rectangular plate shape with its longitudinally opposite side edges bent .

The support main body 130 which is mounted on the cover bottom 150 and has a rectangular frame shape covering the edges of the liquid crystal panel 110 and the backlight unit 120 is combined with the top cover 140 and the cover bottom 150.

The top cover 140 may be referred to as a case top or a top case. The guide panel 130 may be referred to as a support main or a main support or a mold frame. The cover bottom 150 may be referred to as a bottom cover.

The liquid crystal display device of the present invention as described above is modularized as compared with the conventional liquid crystal display device, which will be described in detail with reference to FIG. 3 below.

3 is a cross-sectional view schematically showing a modularized state of the liquid crystal display device of FIG.

As shown in the figure, the liquid crystal display device of the present invention has a reduced total height compared to the conventional liquid crystal display device. This is because the interval between the lamp 124 of the backlight unit 120 and the diffusion plate 126 d1 'between the lamp 124 and the reflector 122 and the interval d2' between the lamp 124 and the reflector 122 are reduced compared to the conventional spacing (d1, d2 in FIG. 1).

Although the present invention reduces the distance d1 'between the lamp 124 and the diffuser plate 126 and the distance d2' between the lamp 124 and the reflector 122, A lamp mura phenomenon does not occur due to the difference in luminance between the region C 'in which the lamps 124 are located and the spacing region D' between the lamps 124 adjacent to each other, This is because the bar-type light guide plate 200 is arranged.

Since the bar-type light guide plate 200 can be divided into several embodiments according to its detailed configuration, the light guide plate 200 will be described separately.

- First Embodiment -

FIG. 4 is a perspective view illustrating a bar type light guide plate and a lamp according to a first embodiment of the present invention, and FIG. 5 is a schematic diagram illustrating a path of light incident on a bar type light guide plate.

As shown in the figure, a plurality of lamps 124 are arranged in parallel with each other at a predetermined interval, and a bar-type light guide plate 200 is disposed along a length direction of the lamp 124 in a spaced-

Here, the shape of the bar-type light guide plate 200 will be described in more detail. The bar-type light guide plate 200 is made of an acrylic resin having a high transparency and a light transmittance of at least 90% (polymethyl methacrylate) or a cycloolefin resin (zeonor).

The bar-type light guide plate 200 has a substantially hexagonal cross-sectional shape perpendicular to the longitudinal direction.

That is, the upper and lower surfaces 202 and 204 are arranged so as to correspond to each other, the first and second lower side surfaces 208a and 208b that are upwardly bent upward at a predetermined angle from the lower surface 204 and the first and second lower surfaces 208a and 208b, And first and second upper side surfaces 206a and 206b which are concavely rounded to connect a part of the outer circumferential surface of the lamp 124 and connect the upper surface 202 and the upper surface 202b.

Here, the lower surface 204 is one surface facing the reflection plate 122 (FIG. 3) and the upper surface 202 is one surface facing the diffusion plate (126 in FIG. 3) to the opposite surface of the lower surface 204. The first lower side 208a and the second upper side 206b and the second lower side 208b and the first upper side 206a correspond to each other diagonally.

The lower surface 204 may include a pattern of a specific shape to supply a uniform surface light source, such as a prism pattern, an elliptical pattern, a polygon pattern, (hologram pattern).

At this time, the pattern becomes denser toward the central portion of the lower surface 204 of the light guide plate 200, and the light can be further concentrated to the center portion of the light guide plate 200.

The first and second lower side faces 208a and 208b are bent upward at a predetermined angle from the lower face 204 to concentrate light as much as possible toward the center of the bar type light guide plate 200 , And the first and second lower side surfaces 208a and 208b thereof are coated with a reflective material 210.

The reflective material 210 may further condense light toward the center of the bar-type light guide plate 200 through the reflective material 210, such as a synthetic resin having high light reflection efficiency.

Each of the first and second upper side surfaces 206a and 206b is configured to surround at least a quarter of the outer circumferential surface of the lamp 124 so that the first upper side surface 206a of the bar- It is preferable that the second upper side surface 206b of the neighboring bar-type light guide plate 200 surrounds half of the outer circumferential surface of the lamp 124. [

Therefore, all the light emitted to the lower side of the lamp 124 is incident into the bar-type light guide plate 200.

The reflective jaw 230 is configured to be convex on the lower surface toward the center of the bar-type light guide plate 200, and the reflection jaw 230 Are formed along the longitudinal direction of the bar-type light guide plate 200.

Both ends of the reflective jaw 230 are formed in a taper shape whose diameter gradually decreases from the lower surface 204 toward the center of the bar-type light guide plate 200.

The reflective jaw 230 guides the light reflected from the first and second lower sides 208a and 208b toward the center of the bar type light guide plate 200. [

At this time, the upper and lower surfaces 202 and 204 of the bar-type light guide plate 200 are formed to have the same width d as the interval D 'between adjacent lamps 124, ) Type light guide plate 200 preferably corresponds to the distance from the reflective sheet 122 (Figure 3) to the lamp 124. In this case, the height h does not exceed the position of the lamp 124 .

In order to prevent light emitted to the upper side of the lamp 124 from being incident into the inside of the bar type light guide plate 200, light emitted to the upper side of the lamp 124 is guided to the bar type light guide plate The brightness of the area D 'of the adjacent lamps 124 may be higher than that of the area where the lamps 124 are located (C' of FIG. 3).

In addition, the bar-type light guide plate 200 is configured so as to correspond to the entire lengthwise side of the light-emitting side of the lamps 124, but not to both ends of the lamps 124. That is, the bar-type light guide plate 200 has a length shorter than the length of the lamp 124.

This is because the lamp 124 is inserted and fixed to the support side (128 in Fig. 2), so that the length of the bar-type light guide plate 200 is set at the support side 128). ≪ / RTI >

As described above, by arranging the bar-type light guide plate 200 between the plurality of lamps 124 arranged in parallel and spaced apart from each other by a predetermined distance, the light is emitted to the lower side of the lamp 124 as shown in FIG. The majority of the light is incident into the bar-type light guide plate 200 and the incident light is reflected by the bar-type light guide plate 200 by total reflection by the reflective material 210, The light is condensed at the center of the bar-type light guide plate 200 and is emitted to the outside.

Accordingly, the brightness of the spacing region D 'between the neighboring lamps 124 can be improved, and the brightness of the neighboring lamps 124 can be improved compared to the region (C' of FIG. 3) (D 'in FIG. 3) is relatively low to prevent a problem that a lamp mura phenomenon such as a stain defect occurs on the display screen.

Thus, the luminance uniformity of the liquid crystal display device is improved and the overall luminance is also improved.

At this time, though not shown in the figure, the light diffused and reflected from the lower surface 204 is condensed on the upper surface 202 to be incident on the diffuser plate (126 in FIG. 3) and the plurality of optical sheets (129 in FIG. 3) A prism pattern can be formed.

6, the first and second upper side surfaces 206a and 206b may be inclined at a predetermined angle so that the first upper side surface 206a of one bar-type light guide plate 200 may be inclined, And the second upper side surface 206b of the adjacent bar type light guide plate 200 may have a V-cut shape to cover a part of the outer circumferential surface of the lamp 124. [

- Second Embodiment -

Referring again to FIG. 3, the present invention is characterized in that the distance d1 'between the lamp 124 and the diffuser plate 300 of the backlight unit 120 and the distance d2' between the lamp 124 and the reflector 122, When the gap d2 'between the lamp 124 and the reflector 122 is reduced, the gap between the cover bottom 150 and the lamp 124, which is made of a metal material, A leakage current is generated, thereby lowering the light efficiency of the lamp 124.

Therefore, in the second embodiment, the liquid crystal display device is configured to be thin, and a lamp mura phenomenon such as unevenness on the display screen is prevented, and a leakage generated between the cover bottom 150 and the lamp 124 The current is also to be cut off.

FIG. 7 is a perspective view illustrating a bar type light guide plate and a lamp according to a second embodiment of the present invention, and FIG. 8 is a schematic diagram illustrating a path of light incident on a bar type light guide plate.

In this case, the same reference numerals are assigned to the same structures in the description of FIGS. 4 to 5, and duplicated descriptions will be omitted and only differences will be described.

As shown in the figure, a plurality of lamps 124 are arranged in parallel with each other at a predetermined interval and a bar type light guide plate (not shown) is formed along the length direction of the lamp 124 in a spaced- 300).

At this time, an insulating material 320 for blocking a leakage current generated between the lamp 124 and the cover bottom (150 in FIG. 3) is attached to the bar type light guide plate 200 corresponding to the lower part of the lamp 124 Respectively.

That is, the insulating material 320 is formed in a region between the first lower side surface 208a of the bar type light guide plate 200 and the second lower side surface 208b of the bar type light guide plate 200 adjacent thereto The insulating material 320 may be a PET (polyethylene terephthalate) material having excellent electrical insulation.

As described above, by arranging the bar-type light guide plate 200 between the plurality of lamps 124 arranged at regular intervals and spaced apart from each other, the light is emitted to the lower side of the lamp 124 as shown in FIG. Type light guide plate 200 by the total reflection by the reflective material 210 or the reflective jaw 230 or the like so as to be incident on the bar type light guide plate 200, The light is condensed at the center of the bar-type light guide plate 200 and is emitted to the outside.

Accordingly, the brightness of the spacing region D 'between the neighboring lamps 124 can be improved, and the brightness of the neighboring lamps 124 can be improved compared to the region (C' of FIG. 3) (D 'in FIG. 3) is relatively low to prevent a problem that a lamp mura phenomenon such as a stain defect occurs on the display screen.

The leakage current generated between the lamp 124 and the cover bottom (150 in FIG. 3) can be reduced by forming the insulating material 320 on the bar type light guide plate 200 corresponding to the lower portion of the lamp 124 So that the efficiency of the lamp 124 can be improved.

Thus, the luminance uniformity of the liquid crystal display device is improved and the overall luminance is also improved.

The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

1 is a sectional view of a liquid crystal display device using a general direct-type backlight unit.

2 is an exploded perspective view illustrating a liquid crystal display device according to an embodiment of the present invention.

3 is a cross-sectional view schematically showing a modular appearance of the liquid crystal display of FIG. 2;

4 is a perspective view showing a bar type light guide plate and a lamp according to the first embodiment of the present invention.

5 is a schematic view schematically showing a path of light incident on a bar-type light guide plate;

FIG. 6 is a schematic view schematically showing another light guide plate of a bar type according to the first embodiment of the present invention. FIG.

7 is a perspective view showing a bar type light guide plate and a lamp according to a second embodiment of the present invention.

8 is a schematic view schematically showing a path of light incident on a bar-type light guide plate;

Claims (10)

Cover cover and; A plurality of lamps arranged on the cover burdens and spaced apart from each other; A plurality of bar type light guide plates having a first and a second upper side surfaces, the first and second upper side surfaces being spaced apart from each other along the longitudinal direction of the lamp; A plurality of optical sheets positioned above the plurality of lamps; And a liquid crystal panel Wherein the lamp is surrounded by the first upper side surface of the first bar type light guide plate and the second upper side surface of the second bar type light guide plate adjacent thereto by a half of the outer circumferential surface of the lamp, Wherein the liquid crystal display device is a liquid crystal display device. The method according to claim 1, And one half of the outer circumferential surface of the lamp is an outer circumferential surface facing the cover bottom about a virtual line at the center of the lamp. The method according to claim 1, The bar type light guide plate includes upper and lower surfaces that are parallel to each other, first and second lower surfaces that are upwardly bent at a predetermined angle from the lower surface, and first and second lower surfaces, Wherein the bar-type light guide plate has a hexagonal cross-section, and the first and second upper side surfaces are connected to each other. The method of claim 3, Wherein the first and second upper side surfaces are concave and round to surround a part of the outer circumferential surface of the lamp. The method of claim 3, Wherein the first and second upper side surfaces are inclined at a predetermined angle so as to surround a part of an outer circumferential surface of the lamp. The method of claim 3, And a reflective material is coated on the first and second lower side surfaces. The method of claim 3, And a dielectric material corresponding to the lamp is formed between the first and second lower side surfaces. The method of claim 3, And a diffusion pattern is formed on the lower surface. 9. The method of claim 8, Wherein the lower surface is inclined at both ends with a predetermined inclination to form a reflective protrusion protruding upward toward the center of the bar type light guide plate. The method according to claim 1, Further comprising a diffusion plate on the lamp.

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