KR100771650B1 - Backlight panel employing white light emitting diode having red phosphor and green phosphor - Google Patents

Abstract

A backlight panel employing a white light emitting diode is disclosed. This white light emitting diode has a blue light emitting diode chip and a red phosphor and a green phosphor located above the blue light emitting diode chip. Accordingly, color reproducibility is good by backlighting white light having clear wavelengths of red, green, and blue, and white can be realized using a single light emitting diode, thereby reducing the manufacturing cost and thickness of the backlight panel.

Backlit Panels, Light Emitting Diodes, Phosphors

Description

BACKLIGHT PANEL EMPLOYING WHITE LIGHT EMITTING DIODE HAVING RED PHOSPHOR AND GREEN PHOSPHOR}

1 is a cross-sectional view illustrating a conventional backlight panel.

2 is a cross-sectional view illustrating a backlight panel according to an embodiment of the present invention.

3 is a cross-sectional view for describing another embodiment of the backlight panel according to an embodiment of the present invention.

4 is a cross-sectional view for describing a backlight panel according to another embodiment of the present invention.

5 is a cross-sectional view illustrating a white light emitting diode of the present invention.

The present invention relates to a backlight panel for backlighting a display panel. More particularly, the present invention relates to a backlight panel in which a white light emitting diode having a red phosphor and a green phosphor is used as a light source to improve color reproducibility and luminance of a display panel.

Passive display devices, such as liquid crystal displays, can reflect or absorb ambient sunlight or room light to produce an image. Thus, ambient sunlight or room light is required to view the displayed image. However, there is a problem in that the displayed image cannot be viewed when the intensity of ambient sunlight or room light is not sufficient to illuminate the display panel. As an alternative to this problem, a backlight panel for backlighting the display panel is generally adopted.

The backlight panel includes a light source such as an incandescent lamp, a fluorescent lamp or a light emitting diode (LED). The light emitted from the light source illuminates the LCD panel to realize the image. On the other hand, LED is often used as a backlight light source due to its excellent color reproduction, and it is expected to increase its use in the future as it is environmentally friendly.

1 is a partial cross-sectional view for explaining a conventional backlight panel that backlights the LCD panel 17 by adopting a light emitting diode.

Referring to FIG. 1, an LED array is positioned on a printed circuit board 1. The LED array is an array in which red (3r), green (3g) and blue (3b) LEDs are arranged at predetermined intervals.

These LEDs are arranged regularly on the printed circuit board 1 to form an LED module, and a plurality of LED modules are used to backlight the LCD panel 17.

The LEDs employ a lens designed to emit side light and emit daylight almost in the lateral direction.

The reflective sheet 5 is positioned below the light exit surface of the LEDs. The reflective sheet may have a reflective layer 5a thereon. The reflective sheet reflects the light emitted from the LEDs to the upper side.

Meanwhile, the light transmitting layer 7 is positioned on the LEDs. The light transmitting layer is a layer through which light emitted from the LEDs can pass, and is made of a transparent resin such as poly methyl methacrylate (PMMA). The light transmitting layer 7 has light blocking patterns 9 at positions corresponding to the LEDs.

The light blocking patterns are used to prevent light emitted upward from the LEDs from passing through the light-transmitting layer and directed toward the LCD 17. The light-shielding patterns are formed by ESR (eletroslag remelting).

The light transmitting layer 7 and the reflective sheet 5 are spaced apart by a predetermined interval to form a first gap 6a formed of an air layer. The first interval is an area in which red, green, and blue light emitted from the LEDs 3r, 3g, and 3b are mixed with each other.

The diffusion plate 11 is positioned on the light transmission layer 7 to be spaced apart from the light transmission layer 7. The diffusion plate 11 diffuses the incident light to make the light uniform. The diffusion plate and the light transmitting layer 7 are spaced apart by a predetermined interval to form a second gap 10a formed of an air layer. Therefore, the light transmitted through the light transmitting layer 7 is mixed again in the second gap 10a and is incident on the diffusion plate 11.

A brightness enhancement film (BEF) 13, such as a prism sheet, is positioned on the diffusion plate 11. The BEF may consist of two sheets, each of which has an upward prism formed in the longitudinal and transverse directions, respectively. In addition, a dual brightness enhancement film (DBEF) 15, such as a dual brightness enhancement-embossed DBEF-E, may be positioned on the BEF 13. These BEF films 13 and 15 refract light emitted from the diffuser plate 11 at a large directing angle at a narrow directing angle to enter the LCD panel 17. Accordingly, the brightness of the LCD panel is increased.

According to the prior art, since the red, green and blue LEDs are used as the light source, color reproducibility can be improved. However, as using red, green and blue LEDs, it is necessary to mix the light emitted from the LEDs to get uniform light. Accordingly, it is necessary to prevent the light emitted from the LEDs from passing through the light-transmitting layer 7 toward the diffuser plate 11 by using the light shielding pattern 7, and the first spacing 6a and the second. An air layer such as the spacing 10a is required. This leads to an increase in the thickness of the backlight panel.

In addition, light loss occurs while mixing the light emitted from the LEDs. Therefore, this light loss is compensated for by increasing the amount of current supplied to the LEDs, using a larger number of LEDs, or using BEF 13 and DBEF 15 or the like. However, increasing the amount of current or using multiple LEDs increases power consumption. In particular, an increase in the amount of current leads to an increase in heat generated in the LEDs, which may degrade the light shielding layer. In addition, the use of BEF films further increases the thickness of the entire backlight panel and increases the manufacturing cost of the backlight panel.

The technical problem to be achieved by the present invention is to provide a backlight panel that can reduce the manufacturing cost compared to the prior art, and has a thinner thickness.

Another object of the present invention is to provide a backlight panel capable of improving luminance as compared with the prior art.

In order to achieve the above technical problem, the present invention provides a backlight panel employing a white light emitting diode having a red phosphor and a green phosphor. The backlight panel according to an aspect of the present invention includes a light guide plate for emitting light incident from the side direction upward. White light emitting diodes are positioned on the side of the light guide plate to emit white light into the light guide plate. Each of the white light emitting diodes has a blue light emitting diode chip and a red phosphor and a green phosphor positioned on the blue light emitting diode chip. Meanwhile, a diffusion plate is positioned on the light guide plate. According to one aspect of the present invention, by adopting a white light emitting diode having three wavelengths of red, green, and blue, the thickness of the backlight panel can be reduced while ensuring color reproducibility of the liquid crystal display screen.

Meanwhile, a brightness enhancing film and / or a dual brightness enhancing film may be positioned on the diffusion plate. These brightness enhancing films improve the brightness of the backlight panel.

A backlight panel according to another aspect of the present invention includes a diffuser plate having a bottom surface and a top surface. White light emitting diodes are spaced apart from the diffusion plate and arranged below the bottom surface. Each of the white light emitting diodes has a blue light emitting diode chip and a red phosphor and a green phosphor positioned on the blue light emitting diode chip. On the other hand, a reflective sheet is located below the exit surface of the white light emitting diodes. The reflective sheet reflects the light traveling in the direction opposite to the diffuser plate to the diffuser plate. Accordingly, it is possible to reduce the intervals for mixing the light while reducing the color reproducibility of the liquid crystal display screen, thereby reducing the thickness of the backlight panel. In addition, it is possible to improve the brightness by using a light source emitted upwards, it is possible to omit the brightness enhancement films.

Meanwhile, brightness may be further increased by disposing a brightness enhancing film and / or a dual brightness enhancing film on the diffusion plate.

Red phosphors according to aspects of the invention are phosphors that are excited by blue light emitted from a blue LED chip and emit red.

The red phosphor is represented by the following <Formula 1>,

 <Formula 1>

(Ca, Sr) _1-xy Eu _x C _y (S _1-z Se _z )

C is at least one element selected from the group containing Mn and Pb, x is set within the range of 0.0005 to 0.1, y is set within the range of 0.0002 to 0.1, z is within the range of 0 to 1 It may be an alkaline earth metal sulfide system to be set.

Preferably, the alkaline earth metal sulfide-based phosphor is represented by the following <Formula 2>,

<Formula 2>

(Ca, Sr) _{1-x- y} Eu _x Pb _y S

X is set in the range of 0.0005 to 0.01 and y is set in the range of 0.0002 to 0.05.

The green phosphor according to aspects of the invention is a phosphor that is excited by blue light emitted from a blue light emitting diode chip and emits green.

The green phosphor is represented by the following <Formula 3>,

<Formula 3>

a (M ^I O) b (M ^II O) c (M ^III A) d (M ^III ₂ O) e (M ^IV ₂ O ₃ ) f ( ^MV _o O _p ) · g (SiO ₂ ) h ( ^MVI _x O _y )

The M ^I is at least one element selected from the group consisting of lead (Pb) and copper (Cu), the M ^II is beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), At least one element is selected from the group consisting of barium (Ba), zinc (Zn), cadmium (Cd) and manganese (Mn), wherein ^MIII is lithium (Li), sodium (Na), potassium (K) , At least one element is selected from the group consisting of rubidium (Rb), cesium (Cs), gold (Au) and silver (Ag), wherein M ^IV is aluminum (Al), gallium (Ga) and indium (In At least one element is selected from the group containing, and ^MV is germanium (Ge), vanadium (V), neodymium (Nd), tantalum (Ta), tungsten (W), molybdenum (Mo), titanium ( At least one element is selected from the group consisting of Ti), zirconium (Zr) and hafnium (Hf), wherein ^MVI is bismuth (Bi), tin (Sn), antimony (Sb), scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), Odymium (Nd), Promethium (Pm), Samarium (Sm), Europium (Eu), Gadolinium (Gd), Terbium (Tb), Dysprosium (Dy), Holmium (Ho), Erbium (Er), Thulium ( At least one element is selected from the group comprising Tm), ytterbium (Yb) and lutetium (Lu), wherein A comprises fluoro (F), chlorine (Cl), bromine (Br) and iodine (I) At least one element is selected from the group wherein a, b, c, d, e, f, g, h, o, p, x, y are 0≤a≤2, 0≤b≤8, 0≤ c≤4, 0≤d≤2, 0≤e≤2, 0≤f≤2, 0≤g≤10, 0≤h≤5, 1≤o≤2, 1≤p≤5, 1≤x≤ 2, 1≤y≤5 may be an orthosilicate phosphor.

Preferably, the orthosilicate-based phosphor is represented by the following <Formula 4>,

<Formula 4>

((Ba, Sr, Ca) _1-x (Pb, Cu) _x ) ₂ SiO ₄ : Eu, B

B is at least one element selected from the group consisting of Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu X is set in the range of 0 to 1, and Eu and B are set in the range of 0 to 0.2.

Hereinafter, with reference to the accompanying drawings will be described embodiments of the present invention; The following embodiments are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the invention is not limited to the embodiments described below and may be embodied in other forms. In the drawings, widths, lengths, thicknesses, and the like of components may be exaggerated for convenience. Like numbers refer to like elements throughout the specification.

2 is a cross-sectional view for describing a backlight panel for backlighting a liquid crystal display panel 37 (hereinafter, referred to as an LCD panel) according to an embodiment of the present invention.

Referring to FIG. 2, the light guide plate 27 is positioned under the LCD panel 37. The light guide plate converts light emitted from the light source 23w into surface light and emits the light upward. The light guide plate 27 may be made of transparent resin such as transparent acrylic resin, polycarbonate or epoxy resin, glass, or the like. Both surfaces of the light guide plate may be processed into various patterns, such as V-shaped grooves, lens shapes, prism shapes, or hologram patterns. In addition, the reflective sheet 25 may be disposed under the light guide plate.

White light emitting diodes (hereinafter, referred to as LEDs) are provided adjacent to the side surface of the light guide plate. The white LED emits white light toward the side of the light guide plate 27. The white LED may be mounted on the printed circuit board 21, and a plurality of LEDs may be mounted on one printed circuit board 21 to constitute an LED module. The LEDs 23w mounted on the printed circuit board 21 may be simultaneously driven through a circuit printed on the printed circuit board. Meanwhile, the LEDs may be disposed on both side surfaces of the light guide plate 27. Accordingly, the luminance of the LCD panel 37 can be further improved.

The white LED 23w has a blue LED chip, and has a green phosphor positioned on the blue LED chip and converting a part of blue light into green light and a red phosphor converting wavelength into red light. The white LED 23w will be described in detail later with reference to FIG. 5.

Meanwhile, light blocking walls 29 are positioned above and below the white LED 23w. The light shielding wall prevents light emitted from the white LED 23w from being emitted to an area other than the side surface of the light guide plate 27. A reflective layer may be coated on an inner wall of the light blocking wall 27 to reflect light incident on the light blocking wall. The reflective layer may also be formed on an upper surface of the printed circuit board 21.

The diffusion plate 31 is positioned on the light guide plate 27. The diffusion plate 31 may be a thin sheet. The diffusion plate 31 diffuses the light incident from the light guide plate 27 into a uniform light. In addition, a brightness enhancement film 33 and / or a dual brightness enhancement film 35 may be further interposed between the diffusion plate 31 and the LCD panel 37. The BEFs 33 and 35 condense the light emitted from the light guide plate 27 within a predetermined direction to increase luminance.

Since the backlight panel according to an aspect of the present invention is equipped with a white LED and emits uniform white light from the LED, in contrast to the prior art, an air layer for mixing red, green, and blue light is not required. Can be reduced. In addition, since the light emitted from the white LED is directly incident on the light guide plate 27, the light emission luminance can be improved, and the BEFs 33 and 35 can be omitted. In addition, when using BEFs, the brightness can be further improved, thereby reducing the number of LEDs used.

3 is a cross-sectional view for describing another embodiment of the backlight panel according to an embodiment of the present invention.

Referring to FIG. 3, as described with reference to FIG. 2, the diffusion plate 31, the BEFs 33 and 35, and the LCD panel 37 are positioned. Hereinafter, a difference from the backlight panel of FIG. 2 will be described in detail.

The light guide plate 47 is positioned under the diffusion plate 31. The light guide plate 47 has an accommodating groove 47a for accommodating the LEDs on its side. As described with reference to FIG. 2, the light guide plate 47 may be made of a transparent resin such as a transparent acrylic resin, a polycarbonate, or an epoxy resin, glass, or the like, and both surfaces of the light guide plate may have a V-groove as necessary. ), A lens shape, a prism shape, or a hologram pattern. In addition, the reflective sheet 25 may be disposed under the light guide plate. The reflective sheet 25 may be attached to the lower surface of the light guide plate 47, extend to the side of the light guide plate, and have a through hole to accommodate the LEDs in the light guide plate 47.

The white LED 43w is accommodated in the accommodation groove 47a. The white LED is a side emitting LED that emits light substantially parallel along the surface of the light guide plate 47, that is, light perpendicular to the side surface. The side-emitting LED can adjust the direction of the light emitted more narrowly than the LED emitting upward, so that the thickness of the light guide plate 47 can be reduced.

The white LED may be mounted on the printed circuit board 41, and a plurality of LEDs may be mounted on one printed circuit board 41 to constitute an LED module. The LEDs 43w mounted on the printed circuit board 41 may be driven simultaneously through a circuit printed on the printed circuit board. Meanwhile, the LEDs may be disposed on both side surfaces of the light guide plate 47. Accordingly, the luminance of the LCD panel 37 can be further improved.

According to the present embodiment, the thickness of the light guide plate may be reduced by mounting a side light emitting LED that can narrowly adjust the directivity angle.

4 is a cross-sectional view for describing a backlight panel according to another embodiment of the present invention.

Referring to FIG. 4, the diffusion plate 61 is positioned below the LCD panel 67. The diffuser plate has an upper surface and a lower surface. A BEF 63 and / or a DBEF 65 may be interposed between the diffusion plate and the LCD panel 67.

Meanwhile, the white LEDs 53w are spaced apart from the diffuser plate 61 and arranged below the bottom surface of the diffuser plate. Each of the white LEDs 53w has a blue LED chip and a red phosphor and a green phosphor positioned on the blue LED chip. The white LEDs 53w will be described in detail later with reference to FIG. 5.

The white LEDs 53w emit white light toward the diffusion plate 61. The white LED may be mounted on the printed circuit board 51, and a plurality of LEDs may be mounted on one printed circuit board 51 to constitute an LED module. The LEDs 53w mounted on the printed circuit board 51 may be simultaneously driven through a circuit printed on the printed circuit board 51. A plurality of LED modules may be disposed below the diffuser plate 61 for uniform backlighting.

On the other hand, the reflective sheet 55 is located under the exit surface of the white LEDs (53w). The reflective sheet 55 may have a reflective layer 55a thereon. The reflective sheet may be formed of an aluminum sheet, and a reflective layer 55a may be coated thereon. In addition, the reflective sheet 55 may be attached to the printed circuit board 51, as shown.

The reflective sheet 55 and the diffusion plate 61 are spaced apart from each other at a predetermined interval to form a gap 60a formed of an air layer. White light emitted from the white LED 53w is mixed with each other in the gap 60a and is incident on the diffusion plate 61.

The backlight panel according to the present embodiment does not use a separate light guide plate. Therefore, the diffuser plate 61 may be thicker than the diffuser plate 31 of FIG. 2 or FIG. 3 to make the light emitted from the white LED 53w uniform.

On the other hand, the backlight panel according to the present embodiment, unlike the prior art, and employs the top emitting white LED, it is possible to omit the light-transmitting layer (7 of FIG. 1) having the light shielding pattern (9 of FIG. 1). In addition, since the light emitted from the white LEDs 53w is incident directly to the diffuser plate 61, light loss can be reduced, so that the brightness of the LCD panel 67 can be increased. Therefore, the BEF 63 and DBEF 65 can be omitted, so that the thickness of the backlight panel can be reduced.

5 is a cross-sectional view illustrating a white LED 23w, 43w or 53w used in embodiments of the present invention.

Referring to FIG. 5, the white LED has a package body 71. The package body may be formed using an injection, pressing or processing technique, and in particular, may be injection molded using a plastic resin. The package body is formed to have a recess, and lead terminals 73 are exposed in the recess. In addition, the side wall of the groove portion is formed of an inclined surface inclined at a predetermined angle.

The lead terminals 73 extend outside to protrude out of the package body 71. Lead terminals 73 protruding to the outside are connected to the printed circuit board and electrically connected to an external power source. The lead terminals 73 may be bent from outside to enable surface mounting.

Meanwhile, the heat sink 75 may be mounted on the lower portion of the package body 71. The heat sink is mounted to easily dissipate heat generated from the LED chip 77 to the outside. The heat sink 75 may have a base portion and a protrusion protruding upward from the center portion of the base portion. The protrusion is inserted into the package body and exposed to the recess. The heat sink may be inserted into the through hole of the package body after forming the package body 71 having the through hole. Alternatively, the heat sink 75 may be mounted on the package body 71 by placing the lead terminals 73 and the heat sink 75 and forming a package body using an insert molding technique. The heat sink 75 may be electrically insulated from the lead terminals 73, but may be electrically connected to one of the lead terminals.

The blue LED chip 77 emitting blue light is mounted on the heat sink 75. The LED chip 77 is a GaN, InGaN, AlGaN or AlGaInN-based light emitting diode, and emits blue light in the range of 420 to 480 nm. The LED chip 77 has two electrodes to be connected to an external power source. The electrodes may be located on the same side or opposite sides of the LED chip 77. The electrodes may be electrically connected to the lead terminal through an adhesive, or as shown, may be connected to the lead terminal through a bonding wire. In the case of the LED chip having electrodes formed on the same side, as shown in the drawing, two bonding wires may be electrically connected by connecting the LED chip 77 and the lead terminals, respectively. On the other hand, when the electrodes are located on opposite sides of each other, one electrode is connected to the heat sink 75 using a conductive adhesive, and one lead terminal and the heat sink 75 are connected to each other by a bonding wire. The lead terminals can be electrically connected to the LED chip 77.

On top of the blue LED chip 77 is mixed with a portion of the light emitted from the LED chip 77 is excited by blue light to emit white light and excited by the red phosphor 81r and blue light to emit red light, green light A green phosphor 81g emitting light is positioned. The red and green phosphors may be coated on the LED chip 77 or may be contained and positioned in the molding member 79 as illustrated. The molding member 79 may be formed of an epoxy resin or a silicone resin, and may be formed of a single layer or multiple layers.

The red phosphor 81r may be, for example, an alkaline earth metal sulfide-based red phosphor, and the green phosphor 81g may be an orthosilicate green phosphor. More specifically, the alkaline earth metal sulfide-based red phosphor is represented by the following <Formula 1>,

 <Formula 1>

(Ca, Sr) _1-xy Eu _x C _y (S _1-z Se _z )

C is at least one element selected from the group containing Mn and Pb, x is set within the range of 0.0005 to 0.1, y is set within the range of 0.0002 to 0.1, z is within the range of 0 to 1 Is set.

Preferably, the alkaline earth metal sulfide-based phosphor is represented by the following <Formula 2>,

<Formula 2>

(Ca, Sr) _1-xy Eu _x Pb _y S

X is set in the range of 0.0005 to 0.01 and y is set in the range of 0.0002 to 0.05.

The alkaline earth metal sulfide-based phosphor may emit light having a wavelength of 600 nm to 660 nm depending on the composition.

In addition, the orthosilicate-based phosphor is represented by the following <Formula 3>,

<Formula 3>

a (M ^I O) b (M ^II O) c (M ^III A) d (M ^III ₂ O) e (M ^IV ₂ O ₃ ) · ｆ (M ^V _O O _p ) · g (SiO ₂ ) · ｈ ( ^MⅥ _x O _y )

The M ^I is at least one element selected from the group consisting of lead (Pb) and copper (Cu), the M ^II is beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), At least one element is selected from the group consisting of barium (Ba), zinc (Zn), cadmium (Cd) and manganese (Mn), wherein ^MIII is lithium (Li), sodium (Na), potassium (K) , At least one element is selected from the group consisting of rubidium (Rb), cesium (Cs), gold (Au) and silver (Ag), wherein M ^IV is aluminum (Al), gallium (Ga) and indium (In At least one element is selected from the group containing, and ^MV is germanium (Ge), vanadium (V), neodymium (Nd), tantalum (Ta), tungsten (W), molybdenum (Mo), titanium ( At least one element is selected from the group consisting of Ti), zirconium (Zr) and hafnium (Hf), wherein ^MVI is bismuth (Bi), tin (Sn), antimony (Sb), scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), Odymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) , At least one element is selected from the group containing ytterbium (Yb) and lutetium (Lu), wherein A is a group containing fluorine (F), chlorine (Cl), bromine (Br) and iodine (I) At least one element is selected from and a, b, c, d, e, f, g, h, o, p, x, y are 0≤a≤2, 0≤b≤8, 0≤c≤ 4, 0≤d≤2, 0≤e≤2, 0≤f≤2, 0≤g≤10, 0≤h≤5, 1≤o≤2, 1≤p≤5, 1≤x≤2, It is set in the range of 1≤y≤5.

Preferably, the orthosilicate-based phosphor is represented by the following <Formula 4>,

<Formula 4>

((Ba, Sr, Ca) _1-x (Pb, Cu) _x ) ₂ SiO ₄ : Eu, B

B is at least one element selected from the group consisting of Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu X is set in the range of 0 to 1, and Eu and B are set in the range of 0 to 0.2.

The orthosilicate phosphor may emit light having a wavelength of 505 nm to 605 nm, depending on the composition.

Accordingly, the blue LED chip 77 and the phosphors may emit white light having distinct wavelengths of red, green, and blue, thereby improving color reproducibility of the LCD panel.

Meanwhile, a lens 83 covers the LED chip 77 and the phosphors 81r and 81g. The lens may have various shapes. For example, to implement a top emitting LED according to aspects of the invention, the lens may have the shape of a convex lens, as shown. At this time, the curvature of the lens is determined according to the required orientation angle. On the other hand, in order to implement the side-emitting LED as shown in Figure 2 the lens is designed to emit light emitted from the LED chip 77 to the side. Examples of such side-emitting LEDs are the LEDs shown in FIG. 1, and the side-emitting LEDs may be implemented in various lens shapes.

 According to embodiments of the present invention, it is possible to reduce the manufacturing cost compared to the prior art, it is possible to provide a backlight panel having a thinner thickness. In addition, it is possible to provide a backlight panel with improved luminance compared to the prior art.

On the other hand, when using red, green and blue LEDs, as in the prior art, the lifetime and deterioration degree of the LEDs are different. Therefore, it is necessary to attach a color sensor to the upper part of the LCD panel to detect their deterioration and then perform compensation work. However, according to embodiments of the present invention, since the same type of white LEDs are used, the lifespan and deterioration are generally similar, so there is less need for a color sensor and compensation work. Therefore, the operation circuit of the LCD panel can be simplified more.

Claims (8)

A backlight panel comprising light emitting diodes for generating light and a diffusion plate for diffusing light, Each of the light emitting diodes is a blue light emitting diode chip and white light emitting diodes having a red phosphor and a green phosphor positioned on the blue light emitting diode chip. The red phosphor is represented by the following <Formula 1>,  <Formula 1> (Ca, Sr) _1-xy Eu _x C _y (S _1-z Se _z ) C is at least one element selected from the group containing Mn and Pb, And x is set within a range of 0.0005 to 0.1, y is set within a range of 0.0002 to 0.1, and z is an alkaline earth metal sulfide-based red phosphor that is set within a range of 0 to 1. A backlight panel comprising light emitting diodes for generating light and a diffusion plate for diffusing light, Each of the light emitting diodes is a blue light emitting diode chip and white light emitting diodes having a red phosphor and a green phosphor positioned on the blue light emitting diode chip. The red phosphor is represented by the following <Formula 2>, <Formula 2> (Ca, Sr) _1-xy Eu _x Pb _y S X is an alkaline earth metal sulfide-based red phosphor that is set within a range of 0.0005 to 0.01 and y is set within a range of 0.0002 to 0.05. A backlight panel comprising light emitting diodes for generating light and a diffusion plate for diffusing light, Each of the light emitting diodes is a blue light emitting diode chip and white light emitting diodes having a red phosphor and a green phosphor positioned on the blue light emitting diode chip. The green phosphor is represented by the following <Formula 3>, <Formula 3> a (M ^I O) .b (M ^II O) .c (M ^III A) .d (M ^III ₂ O) .e (M ^IV ₂ O ₃ ) .f (M ^V _O O _p ) .g (SiO ₂ ) .h ( ^MVI _x O _y ) The M ^I is at least one element selected from the group consisting of lead (Pb) and copper (Cu), the M ^II is beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), At least one element is selected from the group consisting of barium (Ba), zinc (Zn), cadmium (Cd) and manganese (Mn), wherein ^MIII is lithium (Li), sodium (Na), potassium (K) , At least one element is selected from the group consisting of rubidium (Rb), cesium (Cs), gold (Au) and silver (Ag), wherein M ^IV is aluminum (Al), gallium (Ga) and indium (In At least one element is selected from the group containing, and ^MV is germanium (Ge), vanadium (V), neodymium (Nd), tantalum (Ta), tungsten (W), molybdenum (Mo), titanium ( At least one element is selected from the group consisting of Ti), zirconium (Zr) and hafnium (Hf), wherein ^MVI is bismuth (Bi), tin (Sn), antimony (Sb), scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), Odymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm) , At least one element is selected from the group containing ytterbium (Yb) and lutetium (Lu), wherein A is a group containing fluorine (F), chlorine (Cl), bromine (Br) and iodine (I) At least one element is selected, The a, b, c, d, e, f, g, h, o, p, x, y is 0≤a≤2, 0≤b≤8, 0≤c≤4, 0≤d≤2, 0 ≤e≤2, 0≤f≤2, 0≤g≤10, 0≤h≤5, 1≤o≤2, 1≤p≤5, 1≤x≤2, 1≤y≤5 And a silicate-based green phosphor. A backlight panel comprising light emitting diodes for generating light and a diffusion plate for diffusing light, Each of the light emitting diodes is a blue light emitting diode chip and white light emitting diodes having a red phosphor and a green phosphor positioned on the blue light emitting diode chip. The green phosphor is represented by the following <Formula 4>, <Formula 4> ((Ba, Sr, Ca) _1-x (Pb, Cu) _x ) ₂ SiO ₄ : Eu, B B is at least one element selected from the group consisting of Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu Become, X is set within a range of 0 to 1, and Eu and B are silicate-based green phosphors which are set within a range of 0 to 0.2. The light guide plate according to any one of claims 1 to 4, further comprising a light guide plate for emitting light incident from the side direction upwards, and a diffusion plate positioned above the light guide plate, The white light emitting diodes are positioned on side surfaces of the light guide plate to emit white light into the light guide plate. The backlight panel of claim 5, further comprising at least one of a brightness enhancement film and a dual brightness enhancement film on the diffusion plate. The light emitting device of claim 1, wherein the diffusion plate has a bottom surface and an upper surface, and the white light emitting diodes are spaced apart from the diffusion plate and arranged below the bottom surface, and the emission surface of the white light emitting diodes is disposed. And a reflective sheet for reflecting light propagating in a direction opposite to the diffuser plate to the diffuser plate. The backlight panel of claim 7, further comprising at least one of a brightness enhancing film and a dual brightness enhancing film on the upper surface of the diffusion plate.

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