KR20130014193A - Liquid crystal display - Google Patents

Liquid crystal display Download PDF

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Publication number
KR20130014193A
KR20130014193A KR1020110076157A KR20110076157A KR20130014193A KR 20130014193 A KR20130014193 A KR 20130014193A KR 1020110076157 A KR1020110076157 A KR 1020110076157A KR 20110076157 A KR20110076157 A KR 20110076157A KR 20130014193 A KR20130014193 A KR 20130014193A
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KR
South Korea
Prior art keywords
guide plate
leds
light guide
liquid crystal
led
Prior art date
Application number
KR1020110076157A
Other languages
Korean (ko)
Inventor
이세민
한재정
손지은
김대용
Original Assignee
엘지디스플레이 주식회사
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Priority to KR1020110076157A priority Critical patent/KR20130014193A/en
Publication of KR20130014193A publication Critical patent/KR20130014193A/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G02B3/0006—Arrays
    • G02B3/0037—Arrays characterized by the distribution or form of lenses
    • G02B3/005—Arrays characterized by the distribution or form of lenses arranged along a single direction only, e.g. lenticular sheets
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
    • G02B6/0011—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being planar or of plate-like form
    • G02B6/0033—Means for improving the coupling-out of light from the light guide
    • G02B6/005—Means for improving the coupling-out of light from the light guide provided by one optical element, or plurality thereof, placed on the light output side of the light guide
    • G02B6/0051—Diffusing sheet or layer
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133603—Direct backlight with LEDs
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133606—Direct backlight including a specially adapted diffusing, scattering or light controlling members
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133602—Direct backlight
    • G02F1/133611—Direct backlight including means for improving the brightness uniformity
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/1336—Illuminating devices
    • G02F1/133615—Edge-illuminating devices, i.e. illuminating from the side

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  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Planar Illumination Modules (AREA)

Abstract

PURPOSE: An LCD(Liquid Crystal Display) device is provided to reduce power consumption by reducing the intensity of current which flows through an LED(Light Emitting Diode) by reducing the number of the used LEDs. CONSTITUTION: A light guide plate is arranged on a rear surface of a liquid crystal panel. A lenticular lens array pattern is prepared on a front surface of the light guide plate. An LED array(129) is arranged on both surfaces of the light guide plate in an extension direction of the array pattern. The LED array divides an area in which a plurality of LEDs(129a) is mounted into three or more sections. An arrangement space of the LEDs is broadened in the three or more sections.

Description

[0001] Liquid crystal display [0002]

Embodiments of the present invention relate to a liquid crystal display, and more particularly, to an edge type and a direct type liquid crystal display including an LED.

LCDs have advantages of small size, thinness, and low power consumption, and are used in notebook PCs, office automation devices, and audio / video devices. In particular, an active matrix type liquid crystal display device using a thin film transistor (hereinafter referred to as "TFT") as a switching element is suitable for displaying dynamic images.

The liquid crystal display device includes a backlight unit, a liquid crystal panel, and a driving circuit unit, and a backlight unit is disposed on a rear surface of the liquid crystal panel in which upper and lower substrates interpose liquid crystal, and a driving circuit unit for controlling each of the liquid crystal panel and the backlight unit. The module is installed and completed.

In this case, the backlight unit is divided into an edge type and a direct type, and the division criterion of the method is related to the position of the light source.

The direct type is a method in which the light source is arranged in a constant arrangement on the rear surface of the light guide plate. The direct type has an advantage that high luminance can be obtained because the area for emitting light is large.

The edge type is a method in which the light source is disposed on at least one side of the light guide plate so that the light guide plate is incident on the upper surface by changing the direction of the light incident from the side surface. The edge type is a commonly used method because of the advantages of low power consumption, low cost, light weight, thinning.

The edge type backlight unit may include a light source that emits light, a light source array that mounts the light source, and a light guide plate that emits light from the light source on the side to a surface light source and emits light to the upper and lower surfaces, and light from the lower surface of the light guide plate. The reflective sheet reflects to the upper surface, and the diffusion sheet for diffusing and uniformizing the surface light source from the upper surface of the light guide plate to convert the surface light source into uniform and highly polished surface light source.

The light source may be any one of a light emitting diode (LED), a cold cathode fluorescent lamp (CCFL), and an external electrofluorescent lamp (EEFL).

On the other hand, since the edge type liquid crystal display device has a light emitting function, the concept of using a separate light source called a backlight unit, the uniformity and luminance of the surface light source emitted from the backlight unit greatly affects the screen quality of the liquid crystal display device.

One of the components influencing the determination of the luminance is a light guide plate that first generates and generates a surface light source.

1 is a plan view of a light guide plate showing luminance measurement points in an edge type liquid crystal display. The luminance measuring points are seventeen points arranged at regular intervals on the light guide plate. The vertical column and horizontal column arrangements of the luminance measurement points are arranged at four constant intervals d and w. The gap between the edge of the light guide plate and the edge of the light guide plate is composed of 1 / 3d and 1 / 3w.

In this case, the first point 10 is disposed at the center of the light guide plate and has the highest luminance.

In addition, the region 30 from the second point to the fourth point and the region 20 from the seventh point to the ninth point are portions in which the luminance is lower than that of the first point but much higher than that of the edge region.

In general, the luminance of the surface light source generated in the light guide plate is the brightest in the center region and gradually decreases from the center region to the edge region.

2 is a spectrum illustrating luminance distribution on an upper surface of the light guide plate.

As shown in the figure, the color changes from red to green as it goes from the center area to the border area, which means that the luminance is reduced. In contrast to FIG. 1, the region 30 (FIG. 1) from the second point to the fourth point and the region 20 (FIG. 1) from the seventh point to the ninth point have luminance such that the edge area and the boundary are visible. Appearing bright.

Here, the light guide plate forms a pattern in the lower portion so as to emit a uniform surface light source whose luminance value decreases while going from the center region to the edge region.

FIG. 3A is a two-edge light guide plate lower pattern density graph in which light sources are disposed on both sides of the light guide plate, and FIG. 3B is a one-edge light guide plate lower pattern density graph in which light sources are disposed on one side of the LGP.

Referring to FIG. 3A, since light is scanned from both sides in the case of the two-edge type, the light emitting part is the central part where the area exposed to the light is the smallest and the area where the light is exposed the most.

Therefore, when the density of the lower pattern of the central portion is increased and the density of the lower pattern of the light incident portion is decreased, a uniform surface light source having the highest luminance in the central region can be obtained.

3B, since light is scanned from one side in the case of the one-edge type, the smallest area exposed to the light is the edge portion opposite to the light incident part, and the most exposed area is the light incident part.

Therefore, the density of the lower pattern is increased from the light incident part to the edge part.

On the other hand, the region 30 (FIG. 1) from the second point to the fourth point and the region 20 (FIG. 1) from the seventh point to the ninth point may have a small luminance between the luminance of the first point and the luminance of the edge area. Even if you have a, may not cause the screen stains or other problems.

However, as shown in FIG. 2, there is a problem that the luminance is higher than necessary to increase power consumption.

Therefore, in order to improve this, the density of the lower pattern of the light guide plate is widened to the left and right of the center area, but the brightness of the fifth and sixth points is also dispersed to the left and right, which may result in the bright area in the center becoming a rectangular shape.

Therefore, in order to solve the above problems, embodiments of the present invention have an object to reduce unnecessary brightness and power consumption by varying the intensity of light emitted from the LED for each section on the LED array.

In order to achieve the above object of the present invention, a liquid crystal display device according to an embodiment of the present invention comprises a liquid crystal panel for displaying an image on the front; A light guide plate disposed on a rear surface of the liquid crystal panel and having a lenticular lens array pattern extending in one direction on an upper surface thereof; And an LED array disposed on both side surfaces of the light guide plate in an extending direction of the array pattern, and including a plurality of LEDs, wherein the LED array includes three regions having the same spacing between the regions where the plurality of LEDs are mounted. It is divided into an odd number of sections, characterized in that the plurality of LED arrangement intervals in each section is widened from the middle section of the odd number of sections to both of the lateral direction.

Preferably, the LED array is characterized in that the arrangement intervals of the plurality of LEDs disposed in a pair of symmetrical intervals with the middle section interposed therebetween.

In addition, the LED array is characterized in that the distance between the plurality of LED arrangement interval between neighboring sections from the middle section to the section of the both sides has a difference of more than 1 times 1.6 times or less.

In addition, the LED array is characterized in that the same arrangement interval of the plurality of LEDs in a pair of symmetrical intervals across the middle section.

On the other hand, the liquid crystal display device according to another embodiment of the present invention includes a liquid crystal panel for displaying an image on the front; A light guide plate disposed on a rear surface of the liquid crystal panel and having a lenticular lens array pattern extending in one direction on an upper surface thereof; And an LED array disposed on both sides of the light guide plate in an extending direction of the array pattern, and configured to mount a plurality of LEDs spaced at equal intervals, wherein the LED array has the same area in which the plurality of LEDs are mounted. It is divided into three or more odd intervals having an interval, and characterized in that to reduce the current flowing in the plurality of LEDs in each interval from the middle section of the odd number of sections to both of the lateral direction.

Preferably, the LED array is characterized by equalizing the amount of current flowing through the plurality of LEDs in a pair of symmetrical intervals across the middle section.

In addition, the LED array is characterized in that the magnitude of the current flowing through the plurality of LEDs of the adjacent sections from the middle section to the section in both the lateral direction has a difference of 0.7 times or more and less than 1 times.

On the other hand, the liquid crystal display device according to another embodiment of the present invention includes a liquid crystal panel for displaying an image on the front; A light guide plate disposed on a rear surface of the liquid crystal panel; And an LED array including a plurality of LEDs disposed on a rear surface of the light guide plate, wherein the LED arrays have a wider LED placement interval from the central area of the light guide plate to the edge area.

On the other hand, the liquid crystal display device according to another embodiment of the present invention includes a liquid crystal panel for displaying an image on the front; A light guide plate disposed on a rear surface of the liquid crystal panel; And an LED array including a plurality of LEDs disposed on a rear surface of the light guide plate, wherein the LED array is characterized in that a current flowing through the plurality of LEDs decreases from the central area of the light guide plate to the edge area. .

A liquid crystal display device according to at least one embodiment of the present invention configured as described above,

Using the number of LEDs less than the prior art or lowering the intensity of the current flowing through the LED has the effect of lowering the power consumption.

By lowering the brightness of the part that does not significantly affect the overall brightness, fewer LEDs can be used to produce better brightness than the prior art.

1 is a plan view of a light guide plate showing luminance measurement points in an edge type liquid crystal display.
2 is a spectrum illustrating luminance distribution on an upper surface of the light guide plate.
FIG. 3A is a graph of lower pattern density of a light guide plate having a two-edge type with light sources disposed on both sides of the light guide plate; FIG.
FIG. 3B is a graph illustrating a lower density of light guide plate of one edge type in which a light source is disposed on one side of the light guide plate.
4 is an exploded perspective view of a liquid crystal display according to a first embodiment of the present invention.
Fig. 5A shows a layout plan of the light guide plate and the LED array according to the first embodiment of the present invention.
FIG. 5B is a diagram illustrating a path of light when light is incident by LEDs on both sides on a light guide plate having a lenticular lens array.
6A is a cross-sectional view when the LED array according to the first embodiment of the present invention is divided into three sections.
6B is a cross-sectional view when the LED array according to the first embodiment of the present invention is divided into five sections.
7A is a cross-sectional view when the LED array according to the second embodiment of the present invention is divided into three sections.
7B is a cross-sectional view when the LED array according to the second embodiment of the present invention is divided into five sections.
8A is a diagram illustrating a luminance measurement point of the light guide plate.
8B is a table comparing the prior art with the first and second embodiments of the present invention.
9A is a plan view showing a luminance distribution diagram of a light guide plate of the prior art.
9B is a plan view showing a luminance distribution diagram of the light guide plate of the first embodiment according to the present invention.
9C is a plan view showing a luminance distribution diagram of the light guide plate of the second embodiment according to the present invention.
10 is a cross-sectional view of a liquid crystal display device according to a third embodiment of the present invention.
FIG. 11 is a layout plan view of an LED array of a liquid crystal display according to a third exemplary embodiment of the present invention.
12 is a layout plan view of an LED array of a liquid crystal display according to a fourth exemplary embodiment of the present invention.

Hereinafter, a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

In the present specification, the same or similar reference numerals are given to different embodiments in the same or similar configurations.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

4 is an exploded perspective view of a liquid crystal display according to a first embodiment of the present invention.

As illustrated, the liquid crystal display device includes a liquid crystal panel 110, a backlight unit 120, a support main 130, and a top cover 140.

First, the liquid crystal panel 110 plays a key role in image expression. A thin film transistor (TFT) substrate 112 and a color filter substrate bonded to each other with a liquid crystal layer interposed therebetween. 114.

At this time, although not shown in the drawing, a plurality of gate lines and data lines intersect on the inner surface of the thin film transistor substrate 112 to define a pixel, and a thin film transistor is provided at each intersection to form a transparent pixel electrode formed in each pixel. And one-to-one correspondence is connected.

The inner surface of the color filter substrate 114 includes color filters of red (R), green (G), and blue (B) colors corresponding to each pixel, and each of them includes a gate line, a data line, and a thin film. A black matrix covering non-display elements such as transistors is provided. In addition, a transparent common electrode covering them is provided.

Polarizers (not shown) for selectively transmitting only specific light are attached to upper and lower outer surfaces of the two substrates 112 and 114, respectively.

In addition, the liquid crystal panel 110 has a circuit board 117 connected to at least one edge through a connecting member 116 such as a flexible circuit board or a tape carrier package (TCP) to support the modularization process. The side surface of the main 130 or the bottom cover 150 is properly folded to be in close contact.

Accordingly, when the thin film transistor selected for each gate line is turned on by the on / off signal of the gate driver circuit which is scanned and transmitted, the liquid crystal panel 110 transfers the signal voltage of the data driver circuit to the corresponding pixel electrode through the data line. As a result, the arrangement direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode, indicating a difference in transmittance.

In addition, the backlight unit 120 is further provided to supply light from the rear surface of the liquid crystal panel 110 so that the difference in transmittance is expressed to the outside.

The backlight unit 120 includes an LED array 129, a white or silver reflective sheet 125, a light guide plate 123 mounted on the reflective sheet 125, and a plurality of optical sheets 121 interposed thereon. ).

The optical sheet 121 disposed parallel to the rear surface of the liquid crystal panel 200 includes a diffusion sheet, a prism sheet, and a protective sheet stacked sequentially.

The diffusion sheet includes a base film (not shown) and a diffusion coating layer (not shown) formed on the entire surface of the base film, and diffuses light from the LED array 129 to supply the liquid crystal panel 110. .

In addition, the prism sheet has a triangular prism-like prism formed on an upper surface thereof, and improves luminance by allowing light passing through the diffusion sheet to proceed vertically.

A protective sheet is provided on the prism sheet to prevent external impact or foreign matters from being introduced to protect the diffusion sheet and the prism sheet which are sensitive to dust and scratches.

Meanwhile, the light guide plate 123 disposed on the rear surface of the optical sheet 121 may be manufactured as a flat plate or wedge plate including a transparent resin. The light guide plate 123 may be made of any one of polymethyl metacrylate (PMMA), polyethylene terephthlate (PET), polycarbonate (PC), and polyethylene naphthalate (PEN).

A curved lenticular lens array may be formed on an upper surface of the light guide plate 123 as shown in the drawing. The surface of each lens of the lenticular lens array formed on the upper surface of the light guide plate 123 is a curved surface having peaks and valleys.

Here, both side surfaces of the lenticular lens array in the direction in which the peaks and valleys face the light guide plate 123.

When light is incident on the light guide plate 123 in a direction parallel to the peak and valley directions of the lenticular lens array, the lenticular lens array induces total reflection from the curved surface of the lens and blocks light diffusion by the bone to guide the light guide plate 123. The straightness of the light propagated within can be improved.

In addition, the LED array 129 may be disposed such that a pair of the LED array 129 faces at least one pair of side surfaces of the light guide plate 123.

For example, when the direction of the peaks and valleys of the lenticular lens array shown in the drawing is referred to as a first direction, when the lenticular lens array of the light guide plate 123 is formed in a second direction perpendicular to the first direction, the LED array ( The pair may face each other with the light guide plate 123 centered in the second direction.

In addition, the first embodiment of the present invention represents only a two-edge type backlight unit in which two LED arrays 129 are disposed in the drawing, but one LED array 129 has a single edge type disposed on the side of the light guide plate 123. It may also include a backlight unit. In this case, the LED array 129 may be disposed on one side of the direction in which the peaks and valleys of the lenticular lens array face.

In addition, the first embodiment of the present invention may be applied to a light guide plate having a prism array formed at an interface, in addition to a light guide plate having a lenticular lens array including a light guide plate having light linearity.

The LED array 129 includes a plurality of LEDs 129a and a printed circuit board 129b mounted on one surface of the plurality of LEDs 129a.

The plurality of LEDs 129a emit light having red (R), green (G), and blue (B) colors toward the light incident surface of the light guide plate 123, respectively, and turn on the plurality of RGB LEDs at once. In this way, white light by color mixing can be realized. On the other hand, by using an LED chip (not shown) that emits all the colors of RGB, white light may be implemented in each LED, or an LED that emits completely white, including a chip emitting white color, may be used. .

Here, the plurality of LEDs 129a are arranged in a line on the printed circuit board 129b. In addition, the plurality of LEDs 129a may be disposed such that the arrangement interval between the LEDs 129a becomes wider from the center area of the printed circuit board 129b toward both sides of the center area.

The light emitted from the plurality of LEDs 129a disposed in the LED array 129 is incident to light in a direction parallel to the peak and valley directions of the lenticular lens array of the light guide plate 129.

The printed circuit board 129b equipped with the plurality of LEDs 129a is an electronic circuit board that enables mounting and electrical connection of various electronic devices by printing a wiring pattern (not shown) on an insulating layer such as resin or ceramic. It can be formed of epoxy based FR4 PCB, FPCB (flexible printed circuit board) or MCPCB.

Recently, in order to quickly dissipate heat generated from a plurality of LEDs (129a), more and more MCPCBs are used. In this case, when forming the MCPCB, it is preferable to further form an insulating layer (not shown) such as a polyimide resin material for electrically insulating the MC printed circuit board and the wiring pattern (not shown) made of a metal material.

In this case, the high temperature heat generated from the plurality of LEDs 129a may be transferred to the printed circuit board 129b and emitted to the outside.

The reflective sheet 125 is disposed on the rear surface of the light guide plate 129. The reflective sheet 125 serves to reflect the surface light source emitted downward from the rear surface of the light guide plate to return to the upper surface, and may be made of polyethylene terephthlate (PET), polycarbonate (PC), or the like.

Although not shown in the drawings, an LED housing (not shown) that supports the rear surface of the reflective sheet 125 and mounts the LED array 129 on one side may be further configured. The LED housing (not shown) serves to arrange the light generated from the LED 129a toward the light incident surface of the light guide plate 123 and also serves to radiate heat by diffusing heat generated from the LED array 129.

In addition, a bottom cover 150 accommodating the reflective sheet 125, the light guide plate 123, and the LED array 129 is disposed at a lower portion thereof, and is coupled to the top cover 140 to form a single liquid crystal display device. can do.

Here, the form and operation principle of the LED array 129 of the first embodiment of the present invention will be examined.

Fig. 5A shows a layout plan of the light guide plate and the LED array according to the first embodiment of the present invention.

A stripe pattern is formed on one surface of the light guide plate 123 in one direction according to the formation of the lenticular lens array. In addition, a pair of LED arrays 129 are disposed on both side surfaces of the light guide plate 123 in one direction.

In this case, the plurality of LEDs 129a disposed in the pair of LED arrays 129 have the same arrangement interval, and the arrangement intervals of the plurality of LEDs 129a disposed in the one LED array 129 are in the center region. It can get wider in both directions of the middle region.

The present invention may further improve the linearity of the light emitted from the LED 129a by having a lenticular lens array shape.

FIG. 5B is a diagram illustrating a path of light when light is incident by LEDs on both sides on a light guide plate having a lenticular lens array.

In the figure, the red area is the path through which most of the incident light travels. The red region does not spread from side to side but has a shape extending in one direction.

In the drawing, it can be seen that the present invention can greatly enhance the linearity of the incident LED by using the light guide plate having the lenticular lens array.

This means that the area where the light emitted by one LED affects the brightness of the light guide plate is defined, and the area may be one line area on the upper surface of the light guide plate according to the shape of the lenticular lens array, and thus part of the light guide plate. It also means that the brightness control for the line region can be adjusted using the placement and brightness of the LEDs.

On the other hand, by dividing a plurality of sections on the LED array to change the arrangement of the LED in each section, it is possible to implement the concept of a plurality of LED arrangement intervals to be widened from the middle section of the LED array toward the sections in both side directions.

In this case, the plurality of sections may be divided into even or odd numbers. However, when divided into odd numbers, since the center area is clearly designated, it is more preferable to divide into odd numbers. In this case, the odd-numbered sections may be divided into three or more odd-numbered sections such as three, five, seven, and the like.

6A is a cross-sectional view when the LED array according to the first embodiment of the present invention is divided into three sections, and FIG. 6B is a view when the LED array according to the first embodiment of the present invention is divided into five sections. The cross section is shown.

In FIG. 6A, the LED array 129 is divided into sections I, II, and II ′.

At this time, section I has a smaller spacing between the plurality of LEDs 129a than section II and section II ', and section II and section II' have the same spacing between the plurality of LEDs 129a. That is, the section II and section II ′ may be arranged to show symmetrical arrangement intervals of the LED 129a with the section I therebetween.

In FIG. 6B, the LED array 129 is divided into sections I, II, II ', III, and III'.

 Here, section II and section II 'have symmetrical arrangement intervals of LED 129a with section I therebetween. Section III and Section III 'have symmetrical arrangement intervals of LED 129a with section I therebetween. In addition, the intervals of arrangement of the LEDs 129a are wider from the section I to section III.

At this time, the difference between the intervals of the LED 129a arrangement between neighboring sections in FIGS. 6A and 6B may be 1.6 times or less. For example, it is possible to form the arrangement interval of section II larger than the LED 129a arrangement interval of section I by more than 1 times and 1.6 times or less. In addition, it is possible to form the arrangement interval of section III more than 1 times and 1.6 times or less than the arrangement interval of LED 129a of section II.

As described above, the brightness of the light guide plate can be adjusted by the structure of the first embodiment of the present invention as described above.

That is, in FIG. 6A and FIG. 6B, the light incident surface of the light guide plate corresponding to section I, section II, section II ', section III and section III' is irradiated with light at the brightness of each section, and the light linearity characteristic of the lenticular lens array is shown. The brightness in each line region extending in one direction corresponding to each section is changed.

In summary, a plurality of line regions extending in one direction corresponding to each section of the light guide plate are defined, and the plurality of line regions may adjust luminance of a part of the light guide plate because the brightness is different.

Meanwhile, according to the second embodiment of the present invention, the plurality of sections may be defined in the LED array 129 and the brightness of light in each section may be implemented by a method of changing the magnitude of the current.

7A is a cross-sectional view when the LED array according to the second embodiment of the present invention is divided into three sections, and FIG. 7B is a view when the LED array according to the second embodiment of the present invention is divided into five sections. The cross section is shown.

The liquid crystal display according to the second embodiment of the present invention differs from the first embodiment of the present invention only in the arrangement and driving principle of the plurality of LEDs 129a of the LED array 129, and thus, the rest of the configuration will be described. Is replaced with that described in the first embodiment.

Here, the second embodiment is structurally different from the first embodiment in that all intervals of the LED 129a are equally spaced in each section.

In FIG. 7A, the LED array 129 is divided into sections I, II, and II ′.

At this time, section I can increase the current flowing through the plurality of LEDs 129a than section II and section II ', and section II and section II' can equalize the current flowing through the plurality of LEDs 129a. That is, it can be said that section II and section II 'have symmetrical LED 129a currents with section I therebetween.

In FIG. 7B, the LED array 129 is divided into sections I, II, II ', III, and III'.

 Here, section II and section II 'have the same magnitude of LED 129a current in symmetry with each other with section I therebetween. Section III and Section III 'have the same magnitude of LED 129a current in symmetrical fashion with section I therebetween. In addition, the magnitude of the current flowing through the LED 129a becomes smaller as it goes from section I to section III.

In this case, in FIG. 7A and FIG. 7B, the magnitude difference between the currents flowing through the LEDs 129a between neighboring sections may be 0.7 times or more. For example, it is possible to make the current of the LED 129a in the II section smaller than the current of the LED 129a in the I section by 0.7 times or more and less than 1 times. Then, the current of the LED 129a in the III section can be made 0.7 times or more smaller than the current of the LED 129a in the II section.

According to the second embodiment of the present invention configured as described above, since the LED 129a having the reduced magnitude of the light emission becomes smaller, the brightness of each section may be adjusted.

Accordingly, similar to the first embodiment, a plurality of line regions extending in one direction corresponding to each section are defined on the light guide plate, and the plurality of line regions may adjust luminance of a part of the light guide plate because the brightness is different.

FIG. 8A is a diagram illustrating a luminance measurement point of the light guide plate, and FIG. 8B is a table comparing the first and second embodiments of the present invention with the prior art.

In FIG. 8A, the regions in which the LED array is disposed are the tenth, thirteenth and fifteen point regions, and the twelfth, fourteenth and seventeenth point regions.

The line region connecting the tenth point and the twelfth point is called an a line, and the line region connecting the fifteenth point and the seventeenth point is called an e line. It is called c line and d line.

Since the brightness of the LED array has the highest value in the middle section, the most light is scanned in the c line. In addition, since the lower pattern density of the LGP is most densely arranged in the central region of the LGP, the luminance is highest at the first point. On the other hand, the lowest luminance appears from the tenth point to the seventeenth point corresponding to the edge of the light guide plate. In this case, the luminance difference from the tenth point to the seventeenth point with respect to the first point is preferably 60% or less.

Next, a second large amount of light is scanned on the b-line and the d-line on either side of the c-line.

In this case, in the prior art, a plurality of LEDs of the LED array are arranged at equal intervals, and thus the same luminance as that of the LEDs scanned on the c line is scanned from the a-line to the e-line so that a higher luminance than necessary is shown at the points of the b-line and the d-line.

However, in the present invention, the luminous intensity of the LED array corresponding to the b-line and the d-line is lower than that of the LED array corresponding to the c-line so that the points of the b-line and the d-line (i.e., the second, third, and fourth points) 7th, 8th, and 9th points), luminance higher than necessary can be reduced.

If so, the first and second embodiments of the present invention will be distinguished from the prior art when the unnecessary luminance is reduced.

In the case of the first embodiment, compared to the prior art in which the spacing of the LEDs in the middle section is equally arranged in the entire area of the LED array in the first embodiment, the LED spacing is further increased from the middle section to the sections in both lateral directions. The wider the number of LEDs to be mounted than in the prior art. In other words, this means that power consumption is consumed smaller.

In addition, when the number of LEDs used in the prior art and the first embodiment is the same, the first embodiment of the present invention can provide a liquid crystal display having better luminance than the prior art.

In the second embodiment, compared to the prior art in which the current flowing through the LEDs in the center section is equally provided to the LEDs in the entire area of the LED array in the second embodiment, the LEDs are provided to the LEDs more gradually from the middle section to the both side sections. Since the current is reduced, the power consumed in the LED array is smaller than in the prior art.

8B, since the first embodiment of the present invention uses fewer LEDs than the prior art, and the second embodiment uses less current than the prior art, the luminous flux of the entire LED is about 10% lower than that of the prior art. .

Accordingly, the luminance of the first point is also about 4% lower than that of the prior art, but the luminance uniformity has a value of about 1.2, which is similar to that of the prior art. In this case, the luminance uniformity is a value obtained by dividing the minimum value from the highest value of the luminance values of 17 points.

According to the above results, the embodiments of the present invention do not deviate significantly from the range of specifications required by the finished product even if the luminance is provided about 4% lower within the range of no problem such as staining on the screen. It can provide a liquid crystal display device.

In addition, it is possible to provide a liquid crystal display device having a uniform luminance uniformity and a power consumption reduced by about 5% compared to the related art.

Here, the reduction of power consumption in the display field, which is becoming increasingly competitive in terms of price and power consumption, can provide a great competitive advantage.

FIG. 9A is a plan view showing a luminance distribution diagram of a light guide plate according to the related art. FIG. 9B is a plan view showing a luminance distribution diagram of a light guide plate according to a first embodiment according to the present invention. FIG. 9C is a plan view showing a luminance distribution diagram of a light guide plate according to a second embodiment according to the present invention. Top view.

In FIG. 9A, the elliptical red stripe region surrounding the center region is distributed up and down widely. In FIGS. 9B and 9C, the red stripe region corresponding to FIG. 9A is distributed in a smaller round shape. The reason for this result is that the luminance of the second, third, fourth point and the seventh, eighth, and ninth points is lower than that of the prior art. However, the red stripe region is applied with a round uniform thickness, so the luminance uniformity is not significantly different from the prior art.

The third and fourth embodiments of the present invention are characterized by introducing the principles applied to the first and second embodiments into a direct type liquid crystal display.

10 is a cross-sectional view of a liquid crystal display device according to a third embodiment of the present invention.

As shown in the drawing, the direct type liquid crystal display according to the third embodiment of the present invention includes a liquid crystal panel 210 including a color filter substrate 214 and a thin film transistor substrate 212 below the color filter substrate 214. The bottom cover 250 which is fastened to the lower surface of the support main 230 by fastening the support main 230 having a rectangular through hole formed from the upper surface to the lower surface of the support main 230, and the bottom cover ( Reflective sheet (not shown) installed on the upper surface of 250 to reflect light, LED array 229 mounted on the upper surface of the reflecting sheet (not shown) to mount a plurality of LEDs 229a for emitting light, and a plurality of It consists of an optical sheet 220 is installed on the top of the LED 229a and the top cover 240 wrapped from the edge of the liquid crystal panel 210 to the side of the support main 230.

In addition, the center area of the LED array 229 may be densely arranged in the LED array 229, and the LED 229a may be arranged to be smaller toward the edge area. This will be described in more detail with reference to FIG. 11.

FIG. 11 is a layout plan view of an LED array of a liquid crystal display according to a third exemplary embodiment of the present invention.

The LEDs are formed at intersections of diagonal lines extending in different directions. The diagonals are arranged such that the center area of the LED array is narrow and the edge area is wide.

At this time, in the drawing, d1 is formed at a narrower interval than d2, and the interval of d2 may become larger toward the edge direction.

12 is a layout plan view of an LED array of a liquid crystal display according to a fourth exemplary embodiment of the present invention.

Here, the fourth embodiment is different from the third embodiment in the arrangement and operation method of the LED array, and the other configuration is the same as the third embodiment, so the description of the other configuration is replaced with that of the third embodiment.

The LEDs are formed at intersections of diagonal lines extending in different directions. The intervals d3 of the diagonals are arranged to be the same in all regions of the LED array.

However, the size of the current supplied to the LED becomes smaller as it goes from the center region to the edge region.

 Similar to the first embodiment, the third embodiment of the present invention has the effect of reducing the power consumption by reducing the number of LEDs mounted in the related art. In addition, there is an effect that the brightness is further improved compared to the prior art in which the same number of LEDs are mounted.

Similar to the second embodiment, the fourth embodiment of the present invention has an effect of lowering power consumption by varying the distribution of the magnitude of current flowing through the LED.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Therefore, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also within the scope of the present invention.

110, 210: liquid crystal panel 121, 221: optical sheet
123: light guide plate 129, 229: LED array
129a, 229a: LED 129b: printed circuit board
130, 230: support main 140, 240: top cover
150, 250: bottom cover

Claims (9)

A liquid crystal panel displaying an image on the front surface;
A light guide plate disposed on a rear surface of the liquid crystal panel and having a lenticular lens array pattern extending in one direction on an upper surface thereof; And
It includes; LED array disposed on both sides of the light guide plate in the extending direction of the array pattern, and equipped with a plurality of LEDs;
The LED array divides the region in which the plurality of LEDs are mounted into three or more odd intervals having the same interval, and the plurality of LEDs in each of the intervals from the middle section to the lateral sections in the odd number section. Liquid crystal display device characterized in that to widen the LED arrangement interval. The method of claim 1,
And wherein the LED array has the same spacing between the plurality of LEDs arranged in a pair of symmetrical sections with the middle section therebetween. The method of claim 2,
The LED array is a liquid crystal display device characterized in that the distance between the plurality of LED arrangement intervals between neighboring sections from the middle section to the section in both the lateral direction has a difference of more than 1 times 1.6 times. The method of claim 3, wherein
And the LED array has the same arrangement interval of the plurality of LEDs within a pair of symmetrical sections with the middle section therebetween. A liquid crystal panel displaying an image on the front surface;
A light guide plate disposed on a rear surface of the liquid crystal panel and having a lenticular lens array pattern extending in one direction on an upper surface thereof; And
It includes; LED array disposed on both sides of the light guide plate in the extending direction of the array pattern, and mounted with a plurality of LEDs spaced at equal intervals.
The LED array divides the region in which the plurality of LEDs are mounted into three or more odd intervals having the same interval, and the plurality of LEDs in each of the intervals from the middle section to the lateral sections in the odd number section. A liquid crystal display device characterized by reducing the current flowing in the LED. The method of claim 5, wherein
And the LED array has the same magnitude of current flowing in the plurality of LEDs within a pair of symmetrical sections with the middle section therebetween. The method according to claim 6,
The LED array is characterized in that the direction of the current flowing through the plurality of LEDs in the adjacent section from the middle section to the section in both sides, the difference between 0.7 times and less than 1 times the liquid crystal display device, characterized in that . A liquid crystal panel displaying an image on the front surface;
A light guide plate disposed on a rear surface of the liquid crystal panel; And
It includes; LED array equipped with a plurality of LEDs disposed on the back of the light guide plate,
And the LED arrays have a plurality of LED arrangement intervals wider from the center area of the light guide plate to the edge area. A liquid crystal panel displaying an image on the front surface;
A light guide plate disposed on a rear surface of the liquid crystal panel; And
And an LED array including a plurality of LEDs disposed on a rear surface of the light guide plate, wherein the LED array reduces current flowing through the plurality of LEDs from the central area of the light guide plate toward the edge area. Display.
KR1020110076157A 2011-07-29 2011-07-29 Liquid crystal display KR20130014193A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN109581738A (en) * 2017-09-29 2019-04-05 夏普株式会社 Lighting device and display device
US10848490B2 (en) 2014-03-07 2020-11-24 Ubiquiti Inc. Cloud device identification and authentication
US11076404B2 (en) 2014-08-31 2021-07-27 Ubiquiti Inc. Methods and apparatuses for graphically indicating station efficiency and pseudo-dynamic error vector magnitude information for a network of wireless stations

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10848490B2 (en) 2014-03-07 2020-11-24 Ubiquiti Inc. Cloud device identification and authentication
US11076404B2 (en) 2014-08-31 2021-07-27 Ubiquiti Inc. Methods and apparatuses for graphically indicating station efficiency and pseudo-dynamic error vector magnitude information for a network of wireless stations
CN109581738A (en) * 2017-09-29 2019-04-05 夏普株式会社 Lighting device and display device

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