KR102090457B1 - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device, and a liquid crystal display device having a narrow bezel and not generating LED stains.
A feature of the present invention is to form a crescent-shaped hole on a light path through which light from the light guide plate of the backlight unit is incident.
Through this, by widening the angle of incidence of the light incident into the light guide plate, even if the gap between the light guide plate and the LED, which is the optical gap or air gap of the backlight unit, is narrowed to realize the narrow bezel, a dark portion occurs in the region between adjacent LEDs. This can prevent the occurrence of the LED mura phenomenon.
Accordingly, it is possible to prevent a problem of a decrease in display quality of the liquid crystal display device due to luminance unevenness.

Description

Liquid crystal display device

The present invention relates to a liquid crystal display device, and a liquid crystal display device having a narrow bezel and not generating LED stains.

The liquid crystal display device (LCD), which is actively used in TVs, monitors, etc. because it is advantageous for moving picture display and has a large contrast ratio, is an optical anisotropy and polarization of liquid crystal. It shows the principle of image implementation.

This liquid crystal display device is a liquid crystal panel (liquid crystal panel) bonded by interposing a liquid crystal layer between two substrates (substrate) as an essential component, the electric field in the liquid crystal panel to change the arrangement direction of the liquid crystal molecules to realize the difference in transmittance do.

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

The backlight unit uses a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp, and a light emitting diode (LED).

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

On the other hand, the general backlight unit is divided into a direct type (Direct type) and an edge type (Edge type) method according to the arrangement structure of the lamp. In the edge type method, one or a pair of light sources has one or two or two pairs of light guide plates. A light source has a structure disposed on each side of each of the light guide plates, and the direct type method is a structure in which several light sources are disposed on a lower portion of the liquid crystal panel.

Here, the direct-type method has a limitation in thinning, and is mainly used in a liquid crystal display device in which brightness is more important than the thickness of the screen. The edge-type method that is lighter and thinner than the direct-type method is the same as a notebook PC or a monitor PC. It is mainly used in liquid crystal displays where thickness is important.

1 is a cross-sectional view of a liquid crystal display device including a general edge type backlight unit using an LED as a light source, and FIG. 2 is a diagram schematically showing an emission angle through which light is emitted from the LED of FIG. 1.

As illustrated, a liquid crystal display device including a general edge type backlight unit 20 includes a liquid crystal panel 10 and a backlight unit 20, a guide panel 30, a cover bottom 50, and a top cover ( 40).

The liquid crystal panel 10 is a part that plays a key role in image display, and is composed of first and second substrates 12 and 14 adhered to each other with a liquid crystal layer interposed therebetween.

The backlight unit 20 is provided behind the liquid crystal panel 10.

The backlight unit 20 is arranged along the longitudinal direction of at least one edge of the guide panel 30, a plurality of LEDs 29a and an LED assembly 29 made of a PCB 29b on which the LEDs 29a are mounted, It includes a white or silver reflective plate 25 mounted on the cover bottom 50, a light guide plate 23 mounted on the reflective plate 25, and an optical sheet 21 positioned thereon.

The liquid crystal panel 10 and the backlight unit 20 have a top cover 40 that surrounds the top edge of the liquid crystal panel 10 and a back surface of the backlight unit 20 in a state where the edges are surrounded by a rectangular frame-shaped guide panel 30. Cover cover (50) covering each is coupled in front and rear respectively, and is integrated through the guide panel (30).

In addition, reference numerals 19a and 19b denote a polarizing plate attached to the front and rear surfaces of the liquid crystal panel 10 to control the polarization direction of light, respectively.

At this time, the LED assembly 29 is disposed on one side of the light guide plate 23 to distribute the light to the entire surface using the light guide plate 23 to supply a surface light source to the liquid crystal panel 10.

On the other hand, in recent years, such liquid crystal display devices, as well as portable computers, desktop computer monitors, and wall-mounted televisions, etc., are increasingly in use, and researchers who want to have a significantly reduced weight and volume while having a large display area. It is actively progressing.

Particularly, in recent years, a liquid crystal display device is required for a liquid crystal display device having a narrow bezel that is lightweight and thin, and has a wide display area and a non-display area bezel area as small as possible. Is becoming.

Therefore, in order to implement the narrow bezel, the width called the optical gap or air gap of the backlight unit 20, that is, the gap B between the LED 29a and the light guide plate 23 is narrowed. Now, if the distance B between the LED 29a and the light guide plate 23 is reduced, an LED mura phenomenon occurs.

However, in order to supply the 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 for this are considered, one of which is between the LED 29a and the light guide plate 23. Maintaining the interval (B) of the key serves as an important factor.

In particular, in the case of the LED 29a having a certain directivity angle, light emitted from 2 to 3 LEDs 29a adjacent to each other overlaps and mixes with each other, and then enters the light guide plate 23, wherein the LED 29a As shown in FIG. 2, the narrower the distance B between the light guide plate 23 and the light guide plate 23, the light guide plate 23 has a dark portion (A) that does not reach the light between the adjacent regions of the LED 29a. Is done.

Due to this, the LED mura phenomenon occurs, and further causes a problem of deterioration in display quality of the liquid crystal display device due to luminance unevenness.

Thus, by reducing the distance (P) between the LED (29a) and the adjacent LED (29a) to solve this problem, this causes an increase in the cost and heat dissipation (放熱) problems such as the increase in the number of LED (29a) It is becoming a factor that increases power consumption.

Also, a lightweight liquid crystal display device cannot be implemented.

The present invention is to solve the above problems, and a first object of the present invention is to provide a liquid crystal display device having a lightweight, thin, and narrow bezel.

In addition, the second object is to solve the defects such as LED unevenness (mura), and through this, the third object is to prevent the problem of deterioration in display quality due to uneven luminance of the liquid crystal display device.

In order to achieve the object as described above, the present invention is a plurality of LEDs on the PCB LED assembly is mounted spaced apart at regular intervals; A light guide plate including an incident surface on which light emitted from the LED assembly is incident, and having a crescent shape hole formed on the optical path to which the light is incident; A reflector positioned on the rear surface of the light guide plate; An optical sheet positioned above the light guide plate; It provides a liquid crystal display device including a liquid crystal panel mounted on the optical sheet.

At this time, the crescent-shaped hole is formed of first and second arcs having different curvature radii, respectively, and the radius of curvature of the first arc is larger than that of the second arc, and the first and second arcs Has a radius of curvature convex to the opposite side of the light incident surface of the light guide plate.

And, inside the crescent-shaped hole is filled with a resin having a lower refractive index than air or the light guide plate, the length of the string of the crescent-shaped hole is larger than the width of the LED, and the crescent-shaped hole is Located in correspondence with the LED.

Here, the length of the string of the crescent-shaped hole corresponds to the width of the LED, and the crescent-shaped hole is located in correspondence with an area between the LEDs adjacent to each other, and each of the first arc or the second arc is A micro serration pattern is formed, or a micro serration pattern is formed in the first and second arcs.

At this time, the micro serration pattern (micro serration pattern) is made of a lenticular lens (lenticular lens) or a prism lens (prism lens).

As described above, by forming a crescent shape hole on a light path through which the light of the light guide plate of the backlight unit is incident, according to the present invention, thereby widening the directivity of the light incident into the light guide plate, Even if the distance between the light guide plate and the LED, which is the optical gap or air gap of the backlight unit, is reduced to implement the narrow bezel, it is possible to prevent the dark portion from occurring in the region between adjacent LEDs, resulting in an LED mura phenomenon. There is an effect that can be prevented.

Accordingly, there is an effect of preventing a problem of a decrease in display quality of the liquid crystal display device due to luminance unevenness.

1 is a cross-sectional view of a liquid crystal display including a general edge type backlight unit using an LED as a light source.
2 is a view schematically showing an emission angle through which light is emitted from the LED of FIG. 1;
3 is an exploded perspective view of a liquid crystal display device according to an embodiment of the present invention.
4 is a perspective view schematically showing a light guide plate according to an embodiment of the present invention.
Figure 5a is a perspective view schematically showing the LED assembly and the light guide plate according to an embodiment of the present invention.
5B is a plan view schematically showing a traveling path of light of FIG. 5A.
Figure 5c is an enlarged view showing the enlarged C of Figure 5b.
6 is a plan view schematically showing an LED assembly and a light guide plate according to another embodiment of the present invention.
7A to 7D are views schematically showing various structures of a crescent-shaped hole according to an embodiment of the present invention.
8A to 8C are simulation results obtained by comparing optical progress of a liquid crystal display device according to an embodiment of the present invention with a general liquid crystal display device.

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

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

As illustrated, the liquid crystal display device is composed of a liquid crystal panel 110, a backlight unit 120, a guide panel 130, a cover bottom 150, and a top cover 140.

Looking at each of these in detail, first, the liquid crystal panel 110 is a part that plays a key role in image display, and includes first and second substrates 112 and 114 bonded to each other with a liquid crystal layer interposed therebetween. .

At this time, under the premise of an active matrix method, although not clearly shown in the drawings, a plurality of gate lines and data lines cross each other, and pixels are defined on the inner surface of the first substrate 112, which is usually called a lower substrate or an array substrate. In addition, a thin film transistor (TFT) is provided at each intersection, and is connected one-to-one to a transparent pixel electrode formed in each pixel.

And the inner surface of the second substrate 114, called an upper substrate or a color filter substrate, is an example corresponding to each pixel, such as red (R), green (G), blue (B) color filter (color filter) and these A black matrix is provided to cover non-display elements such as a gate line, a data line, and a thin film transistor. In addition, transparent common electrodes are provided to cover them.

The gate and the data printed circuit board 117 are connected via a connecting member 116 such as a flexible circuit board along at least one edge of the liquid crystal panel 110 so that the guide panel 130 side or cover cover in the modularization process. It is in close contact with the back surface of (150).

In addition, although not clearly shown in the drawings, an alignment layer for determining the initial molecular alignment direction of the liquid crystal is interposed at the boundary between the two substrates 112 and 114 of the liquid crystal panel 110 and the liquid crystal layer, and the liquid crystal layer filled therebetween. Seal patterns are formed along the edges of both substrates 112 and 114 to prevent leakage.

At this time, polarizing plates (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 the rear surface of the liquid crystal panel 110 so as to express the difference in transmittance.

The backlight unit 120 includes an LED assembly 129 arranged along at least one edge length direction of the guide panel 130, a white or silver reflective plate 125, and a light guide plate 200 mounted on the reflective plate 125 ) And includes an optical sheet 121 interposed thereon.

The aforementioned LED assembly 129 is a light source of the backlight unit 120, and is located on one side of the light guide plate 200 so as to face the light incident surface 201 of the light guide plate 200, and the LED assembly 129 includes a plurality of LEDs. It includes (129a), and a plurality of LED (129a) PCB (129b) is mounted spaced apart at regular intervals.

In this case, the plurality of LEDs 129a emit light having the colors of red (R), green (G), and blue (B), respectively, toward the light incident surface 201 of the light guide plate 200, and such multiple RGB By lighting the LED 129a at once, white light by color mixing can be realized.

In particular, in order to improve luminous efficiency and brightness, in particular, blue LED 129a including a blue LED chip having excellent luminous efficiency and brightness is used, and as a phosphor, 'cerium doped yttrium aluminum garnet (YAG: Ce)', That is, a blue LED 129a made of a yellow phosphor is used.

The blue light emitted from the LED 129a passes through the phosphor and is mixed with the yellow light emitted by the phosphor, thereby realizing white light.

The light guide plate 200 into which the light emitted from the plurality of LEDs 129a is incident spreads evenly over a wide area of the light guide plate 200 as the light incident from the LED 129a proceeds within the light guide plate 200 by total reflection of the light several times. A surface light source is provided on the liquid crystal panel 110.

Here, a characteristic configuration of the present invention is that a plurality of crescent shape holes (210) are formed corresponding to the light incident portion of the light guide plate (200).

A plurality of crescent-shaped holes 210 are positioned corresponding to the respective LEDs 129a, so that light emitted from the LEDs 129a enters the light guide plate 200 through the light guide plate 200 incident surface 201 , The crescent-shaped hole 210 is refracted above the directivity of the light emitted from the LED 129a.

The light emitted from the LED 129a in the region between adjacent LEDs 129a can be prevented from overlapping and mixing (A of FIG. 2), so that the LED mura phenomenon occurs. Can be prevented. We will look at this in more detail later.

The reflective plate 125 is positioned on the rear surface of the light guide plate 200 to reflect light passing through the rear surface of the light guide plate 200 toward the liquid crystal panel 110 to improve the luminance of the light.

The optical sheet 121 on the light guide plate 200 includes a diffusion sheet and at least one light collecting sheet, and diffuses or collects light passing through the light guide plate 200 to provide a more uniform surface light source to the liquid crystal panel 110. Try to join.

The liquid crystal panel 110 and the backlight unit 120 are modularized through the top cover 140, the guide panel 130, and the cover bottom 150. The top cover 140 includes the top edge of the liquid crystal panel 110 and Configured to cover the sides.

Here, the top cover 140 is a rectangular frame shape in which the cross-section is bent in an “a” shape to cover the top and side edges of the liquid crystal panel 110, and the front surface of the top cover 140 is opened to open the liquid crystal panel 110. It is configured to display an image implemented in.

In addition, the cover bottom 150 on which the liquid crystal panel 110 and the backlight unit 120 are seated and which is the basis for assembling the entire liquid crystal display device is made up of a horizontal surface and an edge portion whose edges are vertically bent.

In addition, a guide frame 130 having a rectangular frame shape with one edge opening around the edges of the liquid crystal panel 110 and the backlight unit 120 and mounted on the cover bottom 150 is covered with the top cover 140. It is combined with the bottom 150.

At this time, the top cover 140 is sometimes called a case top or a top case, the guide panel 130 is also called a support main or main support, a mold frame, and the cover bottom 150 is also called a bottom cover or a bottom cover. Sometimes it loses.

Meanwhile, in order to implement a lightweight and thin liquid crystal display device, the top cover 140 and the cover bottom 150 have been removed, and the liquid crystal panel 110 and the backlight are provided through an adhesive tape (not shown) and a guide panel 130. The unit 120 may be modularized. Through this, material costs can also be reduced.

The above-described liquid crystal display device forms a crescent-shaped hole 210 in the light input portion of the light guide plate 200, thereby widening the direct angle of the light entering the light guide plate 200 than the direct angle of light emitted from the LED 129a. .

Through this, it is possible to prevent the light emitted from the LED 129a from overlapping and not being mixed (A in FIG. 2) from occurring in the region between adjacent LEDs 129a, thereby preventing the LED mura phenomenon. It can be prevented from occurring. Accordingly, it is possible to prevent a problem of a decrease in display quality of the liquid crystal display device due to luminance unevenness.

4 is a perspective view schematically showing a light guide plate according to an embodiment of the present invention.

As shown, the light guide plate 200 according to the embodiment of the present invention is a plastic material such as polymethyl methacrylate (polymethylmethacrylate: PMMA), which is an acrylic transparent resin, which is one of the transmissive materials capable of transmitting light, or It can be manufactured as one selected from polycarbonate (PC), and PMMA, which induces light diffusion when light is transmitted because of its excellent transparency, weatherability, and colorability, is the most widely used.

The light guide plate 200 is connected to the LED assembly (129a in FIG. 3) corresponding to the light incident surface 201 and the opposite side of the light incident surface 203 and the light incident surface 201 and the light incident surface 203 to connect the light It consists of an upper surface 205 to be emitted, a reflecting plate (125 in FIG. 3), a lower surface 207 facing each other, and two side surfaces 209a and 209b facing each other.

The light guide plate 200 includes a pattern of a specific shape on the lower surface 207 to supply a uniform surface light source, and the pattern is an elliptical pattern in order to guide light incident into the light guide plate 200. ), Polygonal patterns, and hologram patterns.

At this time, in order to reduce the thickness d1 of the light guide plate 200 that has the greatest influence on the thickness of the backlight unit (120 in FIG. 3) to realize a light weight and thin liquid crystal display device, the light guide plate 200 has a steeply reduced slope ( 205b) and other portions of the light guide plate 200 except for the light guide portion are formed to have a narrower thickness d2 than the light guide portion of the light guide plate 200.

That is, the upper surface 205 of the light guide plate 200 is formed from the inclined surface 205b and the inclined surface 205b that are inclined from the first upper surface 205a and the first upper surface 205a of the light incident portion of the light guide plate 200. Made of a second upper surface 205c extending in parallel, compared to the thickness d1 from the lower surface 207 to the first upper surface 205a, from the lower surface 207 to the second upper surface 205c The thickness of is formed narrow.

At this time, the optical sheet (121 in FIG. 3) seated on the upper portion of the light guide plate 200 is mounted on the second upper surface 205c of the light guide plate 200, at this time, the light guide plate 200 and the optical sheet (121 in FIG. 3) ), The total thickness d1 of the backlight unit (120 of FIG. 3) does not exceed the thickness d1 from the lower surface 207 of the light incident portion of the light guide plate 200 to the first upper surface 205a.

Through this, the thickness d1 of the backlight unit 120 (of FIG. 3) and the thickness of the liquid crystal display may be reduced.

On the other hand, the light guide plate 200 of the present invention is characterized in that a plurality of crescent-shaped holes 210 are formed on the second upper surface 205c adjacent to the inclined surface 205b.

Here, the crescent-shaped hole 210 is formed to be convex toward the light guide plate 203 of the light guide plate 200, and is composed of first and second arcs 211a and 211b having different curvature radii, respectively. As the radius of curvature of (211a) is formed larger than the radius of curvature of the second circular arc 211b, the first and second circular arcs 211a and 211b define a predetermined space therein, and the gap becomes narrower toward both ends. Is made of

Therefore, it forms a crescent shape in a plane.

Here, air is embedded in a predetermined space inside the first and second arcs 211a and 211b.

The crescent-shaped hole 210 is positioned on an optical path where light emitted from the LED (129a of FIG. 3) of the LED assembly (129 of FIG. 3) enters the light guide plate 200.

Accordingly, the crescent-shaped hole 210 serves as a diffusion portion formed of a light guide plate 200 and a different medium having a different refractive index by air in a predetermined space of the crescent-shaped hole 210 when light is incident.

Through this, the light incident into the light guide plate 200 is refracted beyond the directivity of the LED (129a in FIG. 3), thereby widening the directivity of the light.

Therefore, in order to implement a narrow bezel, even if the gap between the light guide plate 200 and the LED (129a in FIG. 3), which is the optical gap or the air gap of the backlight unit (120 in FIG. 3), is narrowed, the neighbors In the region between the LEDs (129a in FIG. 3), the light emitted from the LEDs (129a in FIG. 3) can be prevented from overlapping and mixing, so that the dark portion (A in FIG. 2) can be prevented, and the LED mura phenomenon This can be prevented from occurring.

This will be described in more detail with reference to FIGS. 5A to 5C.

5A is a perspective view schematically showing an LED assembly and a light guide plate according to an embodiment of the present invention, and FIG. 5B is a plane schematically showing a path of light of FIG. 5A.

And, Figure 5c is an enlarged view showing the enlarged C of Figure 5b.

As shown in the drawing, a plurality of LEDs 129a on the PCB 129b are spaced apart at regular intervals, and the LED assembly 129 mounted on the PCB 129b faces the light incident surface 201 of the light guide plate 200, at this time, the light guide plate 200 On the second upper surface 205c adjacent to the inclined surface 205b, a crescent-shaped hole 210 is formed corresponding to each LED 129a.

At this time, the crescent-shaped hole 210 is formed to be convex toward the light-receiving surface of the light guide plate 200 (203 in FIG. 4), respectively, and is composed of first and second arcs 211a and 211b having different curvature radii, As the radius of curvature of the first circular arc 211a is formed to be larger than the radius of curvature of the second circular arc 211b, the first and second circular arcs 211a and 211b define a predetermined space therein, and the interval becomes larger toward both ends. It is made in a narrowing form.

Here, air is embedded in a predetermined space inside the first and second arcs 211a and 211b.

The crescent-shaped hole 210 is located on an optical path where light emitted from the LED 129a of the LED assembly 129 enters the light guide plate 200.

The light emitted from the LED 129a of the LED assembly 129 facing the light incident surface 201 of the light guide plate 200 is incident into the light guide plate 200 through the light incident surface 201 of the light guide plate 200. , Light emitted from the LED 129a has a constant directivity angle and enters the light guide plate 200.

At this time, the light incident into the light guide plate 200 passes through a crescent-shaped hole 210 in a medium having a large refractive index and a medium having a small refractive index.

That is, since the light guide plate 200 has a refractive index of 1.45-1.59, and the refractive index of air filled in the crescent-shaped hole 210 is 1, light entering the light guide plate 200 is a crescent-shaped hole from the light guide plate 200 In the process of passing through 210, a medium having a large refractive index proceeds to a medium having a small refractive index.

Here, the light is totally reflected in a process in which light progresses from a medium having a large refractive index to a medium having a small refractive index.

Accordingly, the light incident into the light guide plate 200 passes through the light guide plate 200 having a large refractive index, and then passes through the air having a small refractive index, and a critical angle is greater than or equal to a critical angle on a slope of the crescent-shaped hole 210 that becomes a boundary between media having different refractive indexes Will be refracted.

The light refracted along the crescent-shaped hole 210 refracts beyond the directivity of the light emitted from the LED 129a, so that the light refracted by the crescent-shaped hole 210 has a directivity from the LED 129a. It becomes wider than the directivity angle of the emitted light.

As described above, by increasing the directivity of light, it is possible to obtain a result that the color mixing space is increased, and through this, even if the separation distance between the LED 129a and the light guide plate 200 is minimized, in the region between adjacent LEDs 129a. The dark portion (A of FIG. 2) in which light emitted from the LED 129a does not overlap and is not mixed can be prevented from occurring, so that the LED mura phenomenon can be prevented from occurring.

At this time, the length h1 of the string of the crescent-shaped hole 210 may be formed to have a length corresponding to the directivity angle of the light emitted from the LED 129a of the LED assembly 129, and in this case, the crescent-shaped hole ( The length h1 of the string of 210 is preferably formed larger than the width s of the LED 129a that emits light.

On the contrary, as shown in FIG. 6, the length h2 of the string of the crescent-shaped hole 210 may be formed to correspond to the width s of the LED 129a, but of the crescent-shaped hole 210 When the length h2 of the string is formed to correspond to the width s of the LED 129a, it is preferable that the crescent-shaped holes 210 are positioned to correspond to regions between the adjacent LEDs 129a. .

Through this, the light passing through the crescent-shaped hole 210 is refracted above the directivity of the light emitted from the LED 129a, so that the directivity of the light refracted by the crescent-shaped hole 210 is the LED 129a. It becomes wider compared to the directivity angle of the light emitted from it.

7A to 7D are views schematically showing various structures of a crescent-shaped hole according to an embodiment of the present invention.

As shown, the crescent-shaped hole 210 is made of first and second arcs 211a and 211b, which have different curvature radii, respectively, and the radius of curvature of the first arc 211a is that of the second arc 211b. As it is formed to be larger than the radius of curvature, the first and second arcs 211a and 211b define a predetermined space therein, and the gap is narrowed toward both ends.

Here, as shown in FIGS. 7A to 7B, micro serration patterns (213) may be formed in the first and second arcs 211a and 211b, respectively, and the first as shown in FIG. 7C. And micro serration patterns 213 may be formed on both the second arcs 211a and 211b.

The micro serration pattern 213 may be formed of a lenticular lens or a prism lens.

Through the micro serration pattern 213, light diffusion and scattering effects may be further enhanced.

At this time, the height and width of the micro serration pattern 213 of the lenticular lens and the prism lens are irregularly formed, so it is preferable to further increase the light diffusion and scattering effects.

Also, as illustrated in FIG. 7D, the resin 215 may be filled in the crescent-shaped hole 210. The resin 215 filled in the crescent-shaped hole 210 has a transmittance of 90 in a visible light region. It may be made of an acrylic or silicon-based resin having more than%, any resin can be filled if the resin has a lower refractive index than the light guide plate 200.

As described above, the liquid crystal display device of the present invention by forming a crescent shape hole (210) on the optical path to which the light of the light guide plate (200 of FIG. 6) of the backlight unit (120 of FIG. 3) is incident , Widening the angle of incidence of light incident inside the light guide plate (200 in FIG. 6).

Through this, in order to realize a narrow bezel, even if the distance between the light guide plate (200 in FIG. 6) and the LED (200 in FIG. 6), which is the optical gap or air gap of the backlight unit (120 in FIG. 3), is narrowed, the neighboring LED ( In the region between 129a of FIG. 6, the light emitted from the LED (129a of FIG. 6) can be prevented from overlapping and mixing, so that the dark portion (A of FIG. 2) can be prevented from occurring, resulting in an LED mura phenomenon. Can be prevented.

Accordingly, it is possible to prevent a problem of a decrease in display quality of the liquid crystal display device due to luminance unevenness.

8A to 8C are simulation results obtained by comparing optical progress of a liquid crystal display device according to an embodiment of the present invention with a general liquid crystal display device.

Here, FIG. 8A is a simulation result of measuring the optical progress of the general liquid crystal display device, and FIGS. 8B and 8C are simulation results of specifying the optical progress of the liquid crystal display device according to an embodiment of the present invention.

Referring to FIG. 8A, it can be seen that in the case of a general liquid crystal display, a dark portion in which light emitted from the LED is not overlapped and mixed in the region between the LEDs is generated.

On the other hand, referring to Figure 8b, it can be seen that the light emitted from the LED overlaps and mixes in the region between the LEDs.

This is because, as shown in FIG. 8C, the directing angle of the light incident into the light guide plate through the crescent-shaped hole becomes wider.

Through this, even if the distance between the light guide plate and the LED, which is the optical gap or air gap of the backlight unit, is narrowed to realize the narrow bezel, it is possible to prevent the dark portion from occurring in the region between the neighboring LEDs, and the LED mura. There is an effect that can be prevented from occurring.

Accordingly, there is an effect of preventing a problem of a decrease in display quality of the liquid crystal display device due to luminance unevenness.

The present invention is not limited to the above-described embodiments, and can be implemented by variously changing within the limits without departing from the gist of the present invention.

129: LED assembly (129a: LED, 129b: PCB)
200: light guide plate (201: light incident surface)
210: crescent-shaped hole (211a: first arc, 211b: second arc)

Claims (8)

An LED assembly in which a plurality of LEDs are mounted at regular intervals on the PCB;
A light guide plate including a light incident surface from which light emitted from the LED assembly is incident, a crescent shape hole is formed on the optical path from which the light is incident, and having a first refractive index;
A reflector positioned on the rear surface of the light guide plate;
An optical sheet positioned above the light guide plate;
Liquid crystal panel seated on the optical sheet
It includes,
Each of the crescent-shaped holes is composed of first and second arcs having different curvature radii, and the first and second arcs have a convex radius of convexity from the light incident surface of the light guide plate toward the opposite light incident surface,
The vertices of the first and second arcs coincide with the center of the LED,
The inside of the crescent-shaped hole has a second refractive index lower than the first refractive index, and the light emitted from the LED is diffused through the crescent-shaped hole and diffused.
According to claim 1,
The radius of curvature of the first arc located on the side of the light guide plate is greater than the radius of curvature of the second arc located on the side of the light guide plate of the light guide plate. And a second arc, wherein the radius of curvature of the first arc is larger than the radius of curvature of the second arc.
delete According to claim 1,
A liquid crystal display in which the crescent-shaped hole is filled with air or a resin having a lower refractive index than the light guide plate.
According to claim 1,
The length of the string of the crescent-shaped hole is larger than the width of the LED, and the crescent-shaped hole is positioned in correspondence with the LED.
According to claim 1,
The length of the string of the crescent-shaped hole corresponds to the width of the LED, and the crescent-shaped hole is located in correspondence with an area between the adjacent LEDs.
According to claim 2,
A liquid crystal display device in which a micro serration pattern is formed on each of the first arc or the second arc, or a micro serration pattern is formed on the first and second arcs.
The method of claim 7,
The micro serration pattern is a liquid crystal display comprising a lenticular lens or a prism lens.

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