KR20180018867A - Back light unit and liquid crystal display with the same - Google Patents

Abstract

The present invention relates to a backlight unit capable of implementing finer and more precise local dimming in comparison with a conventional one and capable of further improving performance such as power consumption, brightness, visibility, contrast ratio and the like in comparison with the conventional one, and to a liquid crystal display device having the same. The backlight unit according to the present invention comprises: a light source unit; and a light guide panel to which light is incident from the light source unit. The light guide panel includes a light guide panel body, a first light incident unit which is formed on a lower side surface of the light guide panel body and to which light is incident, and a second light incident unit which is formed on an upper side surface of the light guide panel body and to which light is incident. The light source unit includes a first array which consists of a plurality of light emitting elements and is arranged on a side of the first light incident unit, and a second array which consists of a plurality of light emitting elements and is arranged on a side of the second light incident unit.

Description

BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY WITH THE SAME [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a liquid crystal display, and more particularly, to a backlight unit for local dimming in a local dimming of a liquid crystal display.

Currently, smart phones have been actively researched and developed for long-lasting battery power due to portability, and there is a great demand for consumers to reduce their power consumption.

In the current display market, liquid crystal display (LCD) is becoming popular, and such LCD display is continuously developed, and the technology such as 3D-like function or the number of pixels like UHD is implemented, Technological advances are being made to deliver image quality. These developments require that backlighting, which acts as a backlight, also has a differentiating technology.

Currently, liquid crystal display devices require low power consumption technology for backlights that occupy 70% of power consumption. However, in the case of notebooks, tablets, and smartphones where current small and medium-sized displays are used, type backlight of the structure is mainly adopted.

The current liquid crystal display divides the backlight into a plurality of regions for efficient power consumption of the backlight and connects the luminance to the video signal to turn off the backlight or reduce the light in the dark portion of the image, A local dimming method which significantly improves the contrast ratio and the power consumption is applied.

In order to realize such a local dimming technique more effectively, it is necessary to subdivide the backlight driving area into a larger number, and particularly to control the driving of the upper area and the lower area of the light guide plate individually.

However, in the conventional liquid crystal display device, the light source is disposed only on one side of the light guide plate and the local dimming is realized by only one light source as in the prior patent 1 because of the problems such as increase of the bezel size and increase of the optical length of the backlight unit And for this reason, there is a limitation in that it is difficult to realize finer and finer local dimming in the present backlight unit structure.

Prior Patent 1. Korean Patent Publication No. 2015-0062857 (June 2015)

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a backlight unit capable of realizing more precise and detailed local dimming.

It is still another object of the present invention to provide a backlight unit capable of overcoming the limitation of the optical length of the conventional backlight unit and finally reducing the size of the bezel of the liquid crystal display device.

It is still another object of the present invention to provide a backlight unit capable of further improving performance such as power consumption, brightness, visibility, and contrast ratio compared with the conventional one.

According to an aspect of the present invention, there is provided a backlight unit including: a light source; And a light guide plate portion through which light is incident from the light source portion. The light guide plate portion includes a light guide plate main body, a first light entrance portion formed on a lower side portion of the light guide plate main body to which light is incident, Wherein the light source unit comprises a first array formed of a plurality of light emitting devices and disposed on the first light entrance unit side and another light emitting device arranged on the second light entrance unit side, And a second array in which the second array is disposed.

The first light-incident portion and the second light-incident portion each include a serration pattern formed in a serrated shape, and the backlight unit has a first distance between the light-exiting screen of the light guide plate main body and the light- And a second spacing distance between the light exiting screen of the light guide plate main body and the light emitting element of the second array is less than 3.2 mm, and the serration pattern is formed such that the pitch of the saw teeth is 0.06 mm or less .

The first array is composed of N light emitting elements, and the N light emitting elements are grouped in units of M to form N / M (where N > M) first unit luminous bodies, and the second The array is composed of N 'light emitting devices, and the N' light emitting devices are grouped in units of M 'to form N' / M '(where N' M ') second unit light emitters.

The N / M number of the first unit light-emitting bodies is divided into N / M number of driving regions by the N / M number of first unit light-emitting bodies, And the N '/ M' second unit light-emitting bodies are individually controlled so that the upper region of the light guide plate body is divided into N '/ M' The backlight unit is configured to have a driving region divided into a total of N / M + N '/ M' (hereinafter, referred to as a unit driving region).

According to the backlight unit and the liquid crystal display device of the present invention, it is possible to realize finer and finer local dimming compared to the conventional dimming, further improve the brightness, contrast, visibility, etc. of the display device, There is an excellent effect that can save 20% more.

According to the backlight unit and the liquid crystal display of the present invention, it is possible to manufacture a backlight unit having an optical length shorter than the optical length critical point of the related art, and a narrow bezel, Can be implemented.

1 is an exploded perspective view of a liquid crystal display device according to the present invention.
2 is a plan view of a backlight unit according to the present invention;
3 is a side view of the backlight unit according to the present invention
4 is a sectional view of a backlight unit according to the present invention.
5 is a perspective view of a light guide plate according to the present invention.
6 is a sectional view showing a serration pattern according to the present invention.
7 is a plan view showing a unit luminous body and a unit driving region according to the present invention.
8 is a simulated data showing a hot spot phenomenon per pitch of the serration pattern of the present invention.
9A and 9B are graphs showing relative sizes of hot spots per pitch of the serration pattern according to the present invention.
10 is an exemplary diagram for explaining local dimming according to the present invention;

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Also, in the present specification, the term " above or above "means to be located above or below the object portion, and does not necessarily mean that the object is located on the upper side with respect to the gravitational direction. It will also be understood that when an element such as a region, plate, or the like is referred to as being "above or above another portion ", this applies not only to the presence or spacing of another portion & And the like.

Also, in this specification, when an element is referred to as being "connected" or "connected" with another element, the element may be directly connected or directly connected to the other element, It should be understood that, unless an opposite description is present, it may be connected or connected via another element in the middle.

Also, in this specification, the terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

Hereinafter, preferred embodiments, advantages and features of the present invention will be described in detail with reference to the accompanying drawings.

2 is a plan view of a backlight unit according to the present invention, FIG. 3 is a side view of a backlight unit according to the present invention, and FIG. 4 is a cross-sectional view of a backlight unit according to the present invention. FIG. 5 is a perspective view of a light guide plate according to the present invention. FIG.

1 to 5, a liquid crystal display device according to the present invention includes a liquid crystal display panel 100 displaying an image and a backlight unit 140 for providing light to the liquid crystal display panel 100.

The liquid crystal display panel 100 includes a pair of substrates disposed opposite to each other, and a liquid crystal layer interposed between the pair of substrates. The pixel region is defined by a plurality of gate lines and data lines arranged in a matrix on the substrate do. A thin film transistor for controlling a signal supplied to each pixel and a pixel electrode connected to a thin film transistor are formed on a substrate where a gate line and a data line intersect and a color filter and a common electrode are formed on another substrate. And a polarizing plate may be provided on the back surface of the two substrates, respectively.

The backlight unit 140 includes a light source unit 130 for emitting light, a light guide plate 145 for changing the distribution of light provided from the light source unit 130, Optical sheets 110 and 120 for uniforming the luminance distribution and improving vertical incidence, and a reflective sheet 150 for allowing light emitted to the rear of the light guide plate main body 10 to enter the light guide plate.

The light source unit 130 includes a plurality of light emitting devices disposed on both sides of the light guide plate unit 145 and a reflector for reflecting the light emitted from the light emitting device toward the light guide plate. The light emitting element is preferably formed of a point light source such as an LED (Light Emitting Diode), but a tube light source such as a cold cathode tube (fluorescent lamp) for emitting white light may be used.

The light source unit 130 is divided into a first array 20 disposed on one side of the light guide plate unit 145 and a second array 22 disposed on the other side.

The first array 20 is composed of a plurality of light emitting devices 21, and the light emitting devices 21 are arranged in a line on the same axis with mutual spacing. The first array 20 is disposed on the first light-incident portion 31 side of the light guide plate portion 145. More specifically, in the first array 20, the light emitting elements 21 constituting the first array 20 are disposed so as to face the light-entering surface 35 of the first light-incident portion 31, that is, a serration pattern SP to be described later, The light emitting surface of the light emitting element 21 is arranged to be in contact with the light incidence surface 35.

The second array 22 is made up of yet another plurality of light emitting elements 23, which are arranged in a line with mutual spacing on the same axis. The second array 22 is disposed on the side of the second light-incident portion 32 of the light guide plate portion 145. More specifically, in the second array 22, the light emitting elements 23 constituting the second array 22 are disposed so as to face the light incidence surface 37 of the second light-incident portion 32, that is, a serration pattern SP to be described later, The light emitting surface of the light emitting element 23 is arranged to be in contact with the light incidence surface 37.

The optical sheet includes a diffusion sheet 120 for diffusing light incident from the light guide plate main body 10 toward the liquid crystal display panel 100 and a prism sheet 110 for enhancing vertical incidence by condensing the diffused light .

The reflective sheet 150 reflects light emitted to the lower portion of the light guide plate body 10 and re-enters the light guide plate body 10, and any conventional reflective sheet used in the technical field can be used without any particular limitation .

The light guide plate portion 145 includes the light guide plate main body 10 and the light entrance portions 31 and 32 and the light entrance portions 31 and 32 are formed on both sides of the light guide plate main body 10 respectively.

The light guide plate main body 10 has a structure for uniformly changing an optical distribution concentrated on a narrow area over a large area, and is a light guide plate having a structure in which light from the light source unit 130 is repeatedly reflected and refracted, And then exits to the outside.

At this time, the surface light source emergent region of the light guide plate main body 10 is referred to as "effective screen or effective area of the backlight unit 140 ". In the present invention, an effective screen or an effective area (Light Area) of the backlight unit 140 is referred to as an exit screen (L / A). As shown in FIG. 4, the light-exiting screen L / A may correspond to the remaining area excluding the area where the light-out is shielded by the shielding layer 40 from the entire upper surface of the light guide plate.

On the other hand, there is an active area (A / A) in contrast to the light exiting screen L / A. The active area A / A refers to an effective area in which an image is substantially displayed on the liquid crystal display panel 100, and typically a part of the outgoing light screen L / A is used as an active area A / A .

That is, the liquid crystal display device generally forms a larger size of the outgoing light screen L / A than the active area A / A. Normally, the active area A / For example, 0.3 mm) corresponds to the emergence screen (L / A).

The light guide plate main body 10 is a thin plate or film-like member formed of a transparent resin material, and may have a rectangular shape. As the usable resin material, an acrylic resin such as polymethyl methacrylate (PMMA) A polycarbonate resin, a styrene resin, an olefin resin, a polyester resin, or the like can be used.

Also, the light guide plate main body 10 may be provided with light scattering patterns 11 and 13 on at least one surface thereof to supply a uniform surface light source. The light scattering patterns 11 and 13 may be formed in an embossed pattern such as a dot / round-prism / triangular-prism pattern / lenticular pattern, or may be formed in an engraved pattern such as a U cut / V cut / lenticular pattern .

The light scattering patterns 11 and 13 are provided for light scattering, and may be integrally formed with the light guide plate main body 10, and may be formed by a direct processing method, an etching method, a laser processing method, or a sandblasting method.

The light scattering patterns 11 and 13 are configured to have a structure in which the spacing between neighboring intaglio angles (or positive angles) decreases toward the center C1 and is densely arranged. In other words, the distance between the light source unit 130 and the light source unit 130 becomes larger.

3, the backlight unit 140 according to the present invention includes the light source unit 130 on both sides of the light guide plate main body 10 and the left light scattering pattern 11 with respect to the center C1. The pattern interval gradually becomes closer to the central portion C1 from the second array 22 toward the central portion C1 and the pattern interval becomes gradually closer to the central portion C1 from the second array 22 to the light guide plate main body 10 ) At the central portion of the substrate.

It should be noted that the light scattering pattern may be formed so that the embossed pattern gradually increases in size toward the central portion C1 of the light guide plate main body 10. [

The light-incident portion is a region through which the light emitted from the light source 130 is incident. The light-incident portion includes a first light-incident portion 31 formed on the lower side portion of the light guide plate main body 10 and receiving light emitted from the first array 20, And a second light-incident portion 32 formed on the upper side of the light guide plate main body 10 to receive light emitted from the second array 22. [ For reference, the "lower side portion" refers to one edge portion of the light guide panel main body 10, and the "upper side portion" refers to the opposite corner portion of the "lower side portion".

The first light-incident portion 31 and the second light-incident portion 32 may be formed integrally with the light guide plate main body 10 or may be formed separately or in the form of a lens adjacent to or disposed on both sides of the light guide plate main body 10 .

A sawing serration pattern is formed on the light incidence surface 35 of the first light incidence portion 31 and the light incidence surface 37 of the second light incidence portion 32. The serration pattern functions to increase the angle of incidence of light and broaden the scattering range.

6 is a cross-sectional view showing a serration pattern according to the present invention. The characteristic elements of the serration pattern of the present invention will be described in detail with reference to FIG.

Even if the light incident on the first and second light-incident portions 31 and 32 is refracted according to the refractive index of the light guide plate main body 10, the light-shielding portion where the incident light does not overlap with each other appears near the light-incident portion.

When the light emitting surfaces 35 and 37 are provided with a serrated pattern, the light emitted radially from the light source 130 enters the light guide plate 145, is refracted and diffused while passing through the serration pattern SP, . Such a serration pattern SP may be formed in a saw-tooth shape or a semicircular shape along the longitudinal direction of the light incidence surface.

According to the conventional arrangement of the backlight unit, when the optical length of the backlight unit is reduced to less than 3.2 mm, the light emitted from the light source unit 130 is not diffused in the light guide plate main body 10, A phenomenon to be irradiated, that is, a hot spot phenomenon occurs.

The optical length of the backlight unit refers to the distance between the light exiting screen L / A of the light guide plate main body 10 and the light emitting elements 21 and 23 of the light source unit 130 as shown in FIG. L2). In other words, the optical lengths L1 and L2 are the distance from the end of the light emitting elements 21 and 23 (that is, the portion of the light emitting element contacting the light incident surfaces 35 and 37) to the end of the shielding layer 40 . ≪ / RTI > The term " shielding layer 40 "refers to a portion of the bezel region located vertically above the light guide plate main body 10, and the" one end portion of the shielding layer 40 " ) In the longitudinal direction.

This will be described in more detail as follows. In a conventional liquid crystal display device, a light source is provided only on one side of a light guide plate, and a bezel area of about 5.5 mm is formed in accordance with the light source. In other words, in order to ensure the minimum luminance performance required for a liquid crystal display device, a light emitting device having a capacity corresponding to the minimum luminous efficiency should be constructed. To install the light emitting device having such a configuration on one side of the light guide plate, ) Area is essentially required. When a bezel region of about 5.5 mm is formed, an optical length of 3.2 mm or more is provided. This is because, according to the conventional backlight unit structure, when the optical length is less than 3.2 mm, hot spot phenomenon is strongly generated and the display performance is rapidly deteriorated.

However, in the liquid crystal display of the present invention, the light source unit 130 is divided into two (that is, first and second arrays), and the two light source units 130 are disposed on both sides of the light guide plate unit 145 . Accordingly, the first array 20 can be configured as a light emitting device having a capacity smaller than that of the conventional light source unit, thereby reducing the bezel area to a value smaller than 5.5 mm in the prior art. Specifically, the bezel area As shown in FIG. In addition, the optical lengths L1 and L2 can be formed to be smaller than a conventional value, that is, less than 3.2 mm, along with a bezel area of about 3.0 mm.

However, when the optical lengths L1 and L2 are less than 3.2 mm, hot spot phenomenon occurs as described above. The present inventors have found that the pitch P 1 of the serration pattern SP It is possible to improve the hot spot phenomenon caused by the reduction of the optical lengths L1 and L2 when the inclination angle of the serration pattern SP is reduced within a predetermined angle range.

More specifically, according to the present invention, the optical length of the backlight unit 140, that is, the light exit screen L / A of the light guide plate main body 10, And the distance L1 between the light emitting elements of the first array 20 can be less than 3.2 mm and can be reduced to a maximum of 1.35 mm. Similarly, the distance L2 between the light exit screen L / A of the light guide plate main body 10 and the light emitting element of the second array 22 can be reduced to a range of 3.2 mm to 1.35 mm.

The first and second light-incident portions 31 and 32 of the present invention have the following light-incident surfaces 35 and 37 on their light-incident surfaces 35 and 37, respectively, in order to eliminate the hot spot phenomenon caused by the optical lengths L1 and L2 And a serration pattern satisfying the condition is formed.

That is, the serration pattern SP of the present invention is formed such that the pitch P1 of the teeth is 0.06 mm or less, and the angle? 1 between adjacent teeth is 85 to 95 degrees. Here, the "pitch P1 of teeth" means the maximum width of one tooth, which can also be expressed as a distance between the center of the first tooth and the center of the second tooth immediately adjacent thereto. The "inter-tooth angle? 1" means the angle between a pair of adjacent teeth. Therefore, when the angle? 1 between the teeth is formed at 90 °, one tooth is configured to have an upward slope of 45 °.

FIG. 8 shows experimental data showing the hot spot phenomenon for each pitch of the serration pattern SP when the optical lengths L1 and L2 described above are formed to be less than 3.2 mm (1.35 mm in FIG. 8) ) and (b) are comparative graphs showing the relative sizes of hot spots per pitch in FIG.

9 shows that the hot spot value is low as the length of the bar is small in FIG. 9, and the hot spot value is low as the curve chart is positioned below the Y axis in FIG. 9, 1 is formed at 90 [deg.].

9 (a), 9 (b) and FIG. 9, when the tooth pitch P1 of the serration pattern SP is formed at the same value as the conventional one (i.e., 0.1 mm or more), the optical lengths L1, L2 is conventionally smaller than 3.2 mm, hot spot phenomenon occurs strongly, and the display performance required for a normal liquid crystal display device can not be satisfied.

However, the inventor of the present invention has found that even when the optical lengths L1 and L2 are configured to be 1.35 mm, which is reduced from the conventional 3.2 mm width, the toothed pitch P1 of the serration pattern SP is less than 0.1 mm (that is, 0.08 mm) (See Fig. 8 (c)). Particularly, when the thickness is formed to 0.06 mm or less (preferably 0.04 mm or less), the hot spot value is reduced to a level required for a normal liquid crystal display device And it was found.

That is, if the tooth pitch P1 of the serration pattern SP is 0.06 mm or less, the hot spot value begins to decrease rapidly, as shown in Fig. 8 (d) and Fig. 9, The hot spot phenomenon is drastically improved as shown in FIG. 8 (e), so that the normal display performance required for the liquid crystal display device can be satisfied.

As a result, according to the backlight unit 140 of the present invention, the size of the lower bezel of the display device can be further reduced compared with the conventional one by separating the light source unit 130 into two, L1 and L2 are also reduced, the hot spot value can be improved to a level suitable for a normal display device through the above-described serration pattern (SP) structure.

Hereinafter, the local dimming of the present invention driven by the above-described backlight unit configuration will be described.

The backlight unit 140 of the present invention is configured such that the first array 20 and the second array 22 can be independently controlled to be turned on and off so that the driving region is divided into at least an upper region and a lower region of the light guide plate body 10 .

According to a preferred embodiment, the first array 20 is composed of N light emitting elements, and N light emitting elements are bundled in units of M to form N / M (where N M, N / M is a natural number) first And the N / M number of first unit light-emitting bodies are individually configured to be turned on and the amount of light to be controlled.

Similarly, the second array 22 is composed of N 'light emitting elements, and N' light emitting elements are grouped in units of M 'to form N' / M '(where N'≥M', N '/ M' And the N '/ M' second unit light emitters are individually configured to be turned on and the amount of light to be controlled individually.

Therefore, the lower region of the light guide plate main body 10 of the backlight unit 140 is divided into N / M number of driving regions by N / M first unit luminaries, and the upper region is divided into N / M ' The driving area is divided into N '/ M' by the unit luminous body, and the display screen (that is, the light guide plate main body 10) is divided into a driving area divided into a total of N / M + N '/ M' Unit driving region ").

The N / M first unit light emitters and the N '/ M' second unit light emitters are arranged such that a constant brightness is determined according to the value of the current / voltage applied to each of the unit light emitters, .

7 is a plan view showing a unit luminous body and a unit driving region according to the present invention. The local dimming of the present invention will be described in more detail with reference to FIG. 7, for example. The light source unit 130 of FIG. 7 includes a first array 20 including 12 (N) light emitting devices and a second array 22 including 12 (N ') total light emitting devices. The first arrays 20 are grouped in units of 3 (M) and have a total of 4 (N / M) units. The second arrays 22 are grouped in units of 3 (M ') And a total of 4 (N '/ M') unit light emitters.

In this case, the driving area of the display screen (i.e., the light guide plate main body 10) is largely divided into a lower area controlled by the first array 20 and a lower area controlled by the second array 22 To 8).

The lower region is divided into four unit driving regions (1 to 4 in FIG. 7) in detail, and the upper region is divided into four unit driving regions (5 to 8 in FIG. 7) in detail.

More specifically, the first unit driving area (1) is driven by a first unit light emitter including three '21a' light emitting elements, and the second unit driving area (2) ) Is controlled by the first unit light emitting device including three '21b' light emitting devices, and the third unit driving area (3 ') is controlled by the first unit light emitting device of the first (That is, lighting and luminance) is controlled by the unit luminous body, and the fourth unit driving area (4) is driven by the first unit luminous body composed of three '21d' luminous elements, Is controlled.

The fifth unit driving area (5) is driven by the second unit light emitter including three 23a light emitting elements, and the sixth unit driving area (6) is controlled by three (That is, lighting and luminance) is controlled by a second unit light emitter composed of a light emitting element '23b', and the seventh unit driving region (7) is controlled by a second unit light emitter composed of three '23c' The driving (that is, the lighting and the luminance) is controlled, and the eighth unit driving area (8) is controlled by the second unit light emitter composed of three '23d' light emitting elements.

Hereinafter, a method of realizing finer and more accurate local dimming using a plurality of first and second unit luminous bodies and a plurality of unit driving regions as described above will be described.

The backlight unit 140 of the present invention analyzes video signals in a program in brightness control for a certain portion of a screen, compares the cell light amount in each unit driving area, and compares the light amount with a unit Into a power value to be applied to the light-emitting body to finally implement the screen division dimming.

More specifically, in order to realize local dimming, the liquid crystal display device is configured to be able to compute brightness values for each unit driving region divided into a plurality of units as shown in FIGS. 7 and 10. Here, the brightness value may be calculated as a relative ratio (%) to a maximum brightness (i.e., maximum light amount) of the light emitting device.

For example, in the case of a dual view screen as shown in FIG. 10 (a), the right display area is displayed as a normal brightness screen, and the brightness value in this case is calculated as '100%'. The left display area is displayed in a darker screen than the right display area. In this case, a brightness value less than the maximum light amount (for example, 20%) is calculated. Here, the brightness value of '100%' means that the unit light emitting device, that is, the light emitting device is turned on at the maximum amount of light.

For reference, the brightness value of the display area (i.e., the unit driving area) may be calculated by analyzing the image data signal of the image analysis unit, the image analysis unit may be provided in the control unit, and the control unit may include a CPU, Lt; / RTI >

In this way, when the brightness value of each region of the display image is calculated, the backlight unit 140 is controlled to calculate the power value to be applied to each unit luminous body.

For example, when the image data is inputted, the brightness values are compared and calculated for each unit driving area. In the example of Fig. 10 (a), the unit driving areas corresponding to?,?,?, And? Value is 100%, and the unit driving area corresponding to (1), (2), (5), and (6) can be calculated to have a brightness value of 20%.

The brightness value calculated for each unit driving area is converted into the power value of the corresponding unit driving area. Here, the "power value of the unit driving area" means a power value to be applied to the unit luminous body that is responsible for the unit driving area to implement the brightness value calculated through the image data analysis.

When the power value for each unit driving area is calculated through the above process, the control unit is configured to implement local dimming by individually controlling each of the unit luminous bodies according to the power value.

For example, in the case of Figs. 10 (a) and 10 (b), the maximum power for the maximum light quantity of the unit light emitting device (i.e., the brightness value 100%) may be defined as 0.21 mW (10.5v, 20mA) (0.21mW × 20%) are supplied to each unit luminous body which is responsible for the unit driving area of (1), (2), (5) and (6) ) mW of power is supplied, it is possible to implement local division driving, that is, local dimming.

According to the above-described structure, it is possible to realize finer and finer local dimming compared to the conventional dimming, thereby reducing the power consumption by 5 to 20% compared to the prior art, and further improving the brightness, contrast ratio, It was.

While the preferred embodiments of the present invention have been described and illustrated above using specific terms, such terms are used only for the purpose of clarifying the invention, and it is to be understood that the embodiment It will be obvious that various changes and modifications can be made without departing from the spirit and scope of the invention. Such modified embodiments should not be understood individually from the spirit and scope of the present invention, but should be regarded as being within the scope of the claims of the present invention.

10: light guide plate main body 20: first array
21: light emitting element of the first array 22:
23: light emitting element of the second array 31: first light-
32: second light entrance part 35: entrance face of the first light entrance part
37: light-entering surface of the second light-incident portion 40: shielding layer
50: frame 100: liquid crystal display panel
110: prism sheet 120: diffusion sheet
130: light source unit 140: backlight unit
145: light guide plate part 150: reflective sheet

Claims (10)

A light source; And a light guide plate portion on which light is incident from the light source portion,
The light-
A light guide plate main body; A first light-entering portion formed on a lower side portion of the light guide plate main body and receiving light; And a second light-incident portion formed on an upper surface of the light guide plate main body to receive light,
The light source unit includes:
A first array formed of a plurality of light emitting elements and disposed on the first light incoming portion side; And a second array formed of another plurality of light emitting elements and disposed on the second light incoming portion side,
The method according to claim 1,
Wherein each of the first and second light-incoming portions includes a serration pattern formed in a serrated shape,
The backlight unit includes:
(L / A) of the light guide panel main body and a distance L1 between the light emitting elements of the first array is less than 3.2 mm,
(L / A) of the light guide panel main body and a distance L2 between the light emitting elements of the second array is less than 3.2 mm,
The serration pattern
And the pitch (P1) of the teeth is 0.06 mm or less.
3. The method of claim 2,
The spacing distance L1, L2 is 1.35 mm,
And the pitch P1 of the teeth is 0.04 mm.
3. The method of claim 2,
Wherein the first array is composed of N light emitting devices, the N light emitting devices are grouped in units of M to form N / M (N? M) first unit light emitters,
The second array is composed of N 'light emitting devices, and the N' light emitting devices are bundled in units of M 'to form N' / M '(where N' M ') second unit light emitters And,
Wherein the N / M number of first unit light-emitting bodies are respectively controlled so that the N / M number of first unit light-emitting bodies is divided into N / M number of driving regions in a lower region of the light guide plate main body,
The N '/ M' number of second unit light emitters are individually controlled, and the upper region of the light guide plate main body is divided into N '/ M' second unit light emitters by N '/ M' Divided,
Wherein the backlight unit is configured to have a driving region divided into a total of N / M + N '/ M' (hereinafter, referred to as unit driving region).
5. The method of claim 4,
Further comprising a control unit for analyzing the input image data and controlling the driving of the first unit light emitting unit and the second unit light emitting unit,
Wherein,
A first function for calculating a brightness value for each unit driving area based on input image data;
A second function for converting a brightness value calculated by the first function into a power value to be applied to the first unit light emitter or the second unit light emitter responsible for the unit driving area; And
And a third function of controlling the amount of light of the first unit light emitter or the second unit light emitter according to the power value derived by the second function.
6. The method of claim 5,
Wherein the brightness value is calculated as a relative ratio (%) to a maximum light amount of the light emitting device.
3. The method of claim 2,
And a light scattering pattern formed on the upper surface or the lower surface of the light guide plate main body in a negative or positive shape,
Wherein the light scattering pattern is densely arranged closer to a central portion of the light guide plate.
3. The method of claim 2,
Wherein the serration pattern is configured so that an angle? 1 between adjacent teeth between the adjacent serrations is 85 ° to 95 °.
3. The method of claim 2,
Wherein the first light-incident portion and the second light-incident portion are formed integrally with the light guide plate main body, or formed in a lens form separately formed and disposed adjacent to both sides of the light guide plate main body.
A liquid crystal display panel comprising a pair of substrates disposed opposite to each other, and a liquid crystal layer interposed between the pair of substrates; And a backlight unit according to any one of claims 1 to 9.

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