KR102262667B1 - Led array and liquid crystal display device inculding the same - Google Patents

Abstract

The present invention discloses an LED array. More particularly, the present invention relates to an LED array in which a voltage difference (ΔVf) between a plurality of LED strings provided on a straight substrate is improved, and a liquid crystal display including the same.
According to an embodiment of the present invention, by optimizing the width of the cathode wiring according to a plurality of LED strings provided in the LED array for a liquid crystal display device, the voltage deviation (ΔVf) between each LED string is minimized to minimize the localization of the LED array. It has the effect of improving the heat problem and the luminance deviation problem.

Description

LED array and liquid crystal display including same {LED ARRAY AND LIQUID CRYSTAL DISPLAY DEVICE INCULDING THE SAME}

The present invention relates to an LED array, and more particularly, to an LED array in which a voltage difference (ΔVf) between a plurality of LED strings provided on a straight substrate is improved, and a liquid crystal display including the same.

A flat panel display (FPD) replaces a conventional cathode ray tube (CRT) display to reduce the size and weight of not only desktop computer monitors, but also portable computers such as notebook computers and PDAs or mobile phone terminals. It is an essential display device for realizing the system. Currently commercialized flat panel displays include a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting diode (OLED). The device is spotlighted as a display device used in mobile devices, computer monitors, HDTVs, etc. due to advantages such as excellent visibility, easy thinning, low power and low heat generation.

Since the liquid crystal display device is a non-emissive device, a backlight unit is provided for more efficiently providing light to the liquid crystal panel.

The backlight unit includes an LED array including one or more LED packages, and an optical member provided on a path of light emitted from a light source to minimize light loss and to be incident on the liquid crystal panel.

1 is a diagram schematically showing the structure of a backlight unit provided in a conventional liquid crystal display device.

Referring to FIG. 1 , the backlight unit of a conventional liquid crystal display includes one or more LED arrays, and a plurality of LED packages 10 and 16 are connected in series to form a plurality of LED strings st1 to st6, and each string (st1 to st6) are connected in parallel with respect to the connector unit 40 to form one LED array.

Typically, one LED array is mounted on a straight LED substrate (not shown), and each LED string st1 to st6 may include 6 to 8 LED packages 10 and 16 . When the backlight unit is a direct type, a plurality of LED arrays are arranged side by side on the rear surface of the liquid crystal panel to realize a surface light source, and when the backlight unit is a photometric type, one LED array is arranged to correspond to one side of the liquid crystal panel to provide a linear light source. will achieve

In the LED array, the LED packages 10 and 16 in each LED string st1 to st6 have an anode and a cathode connected between neighboring packages, and the first LED packages 10 in each LED string st1 to st6 are It is connected to a plurality of cathode wirings 30 , and the eighth LED packages 16 are connected to one branched anode wiring 20 .

According to this structure, in the conventional LED array 1, the anode wiring 20 is commonly connected with one wiring, but the first to third LED strings st1 to st3 disposed adjacent to the connector part 40 are The cathode wirings 30 connected to the are relatively short, and the cathode wirings 30 connected to the fourth to sixth LED strings st4 to st6 are formed to have a relatively long length.

Accordingly, the length of the cathode wiring 30 increases from the first LED string st1 to the sixth LED string st6, and thus a voltage deviation ΔVf for driving the LED packages 10 and 16 occurs. will do

That is, when a driving voltage is applied to each of the LED strings st1 to st6, the voltage applied to the cathode wiring 30 is lowered by IR drop, and the first LED string st1 is connected to the connector part. As it is disposed adjacent to 40, the resistance of the cathode wiring 30 is relatively low, and as the resistance of the cathode wiring 30 increases toward the sixth LED string st1, each LED string st1 to st6) A deviation occurs in the voltage applied to the

The above voltage deviation (ΔVf) causes a local heating problem and luminance non-uniformity between the LED packages 10 and 16 .

The present invention has been devised to solve the above problems, and the present invention is to provide an LED array in which the voltage deviation (ΔVf) problem between a plurality of strings in an LED array for a liquid crystal display is improved, and a liquid crystal display including the same. There is a purpose.

In order to achieve the above object, an LED array according to a preferred embodiment of the present invention is an LED array used in a backlight unit of a liquid crystal display device, and includes a plurality of LED packages mounted on a straight LED substrate.

In particular, in the present invention, the plurality of LED packages are connected in series to each other to form a plurality of LED strings arranged in a line, and have a structure in which the plurality of LED strings are connected in parallel. In particular, it is characterized in that the thickness of the signal wires connecting the LED string and the connector is determined so that the voltage deviation (ΔVf) is minimized in proportion to their separation distance.

According to an embodiment of the present invention, by optimizing the width of the cathode wiring according to a plurality of LED strings provided in the LED array for a liquid crystal display device, the voltage deviation (ΔVf) between each LED string is minimized to minimize the localization of the LED array. It has the effect of improving the heat problem and the luminance deviation problem.

1 is a diagram schematically showing the structure of a backlight unit provided in a conventional liquid crystal display device.
2 is a plan view showing an LED array for a liquid crystal display according to an embodiment of the present invention.
3A to 3C are enlarged views of portions P1 to P3 of FIG. 2 .
4 is an exploded perspective view of a liquid crystal display including an LED array according to an embodiment of the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be embodied in various different forms, only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

When 'to include', 'includes', 'have', 'consists of', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the case in which the plural is included is included unless otherwise explicitly stated.

Although the first, second, etc. are used to describe various components, these components are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the spirit of the present invention.

Each feature of the various embodiments of the present invention may be partially or wholly combined or combined with each other, technically various interlocking and driving are possible, and each embodiment may be implemented independently of each other or may be implemented together in a related relationship may be

Hereinafter, a structure of an LED array for a liquid crystal display according to an embodiment of the present invention will be described with reference to the drawings.

2 is a plan view showing an LED array for a liquid crystal display according to an embodiment of the present invention.

2, the LED array 100 for a liquid crystal display of the present invention includes a plurality of LED strings (st1 to st6) to which a plurality of LED packages 110 are connected in series, and the plurality of LED strings (st1 to st6). ) a first signal wiring 120 connected in parallel to the first end, and a plurality of second signal wiring 130 respectively connected to the second end of the plurality of LED strings st1 to st6, and the The thickness of the plurality of second signal wires 130 is determined in proportion to the distance between the connector unit 140 and the LED strings st1 to st6.

In detail, the plurality of LED packages 110 is a light emitting diode package in which 6 to 8 are connected in series with each other, each of which emits monochromatic light of red, green, and blue. They may be used in combination, or one type of package emitting only white light may be used.

When the LED package 110 emitting monochromatic light is used, red, green, and blue monochromatic LED packages 110 are arranged at regular intervals so that each color alternates on the LED substrate 115, and the monochromatic light emitted therefrom is disposed. White light, which is mixed light, is used. In addition, when the LED package 110 emitting white light is used, a plurality of packages are arranged at regular intervals to use the white light.

In addition, when the light emitting diode device mounted therein is a red light emitting device that emits red light in the LED package 110 , the inside of the encapsulant included in the LED package 110 is cyan fluorescent material made of a fluorescent material and a blue fluorescent material More layers are added. In addition, when the light emitting diode device is a green light emitting device emitting green light, a red and blue fluorescent layer made of a red fluorescent material and a blue fluorescent material is further added to the inside of the encapsulant. And, in the case of a blue light emitting device emitting blue light, a red-green fluorescent layer made of a red fluorescent material and a green fluorescent material is added to the inside of the encapsulant.

These LED packages 110 are mounted in a line on a straight LED substrate 115 through the SMT technique.

In the LED substrate 115, a plurality of signal wires 120 and 130 made of copper foil are formed on a base substrate having rigid or flexible characteristics, and a soldering resist is applied thereon. At the portion where the LED packages 110 are mounted on the LED substrate 115, pads (not shown) connected to the signal wirings 120 and 130 are exposed through the opening of the soldering resist, and on the pad. The LED packages 110 are bonded.

At one end of the LED board 115 , the connector unit 140 to which the first and second signal wires 120 and 130 connected to the LED package 110 are in contact is provided. Although not shown, the connector unit 140 is electrically connected to a driving driver (not shown) including a DC-DC converter provided outside to receive a voltage when driving. To facilitate connection with the driving driver, the connector unit 140 may be formed in a portion that is bent in a vertical direction from the end of the straight LED board 115 to protrude, and the arrangement of the connector unit 140 is the liquid crystal display device. It can be changed depending on the type.

Meanwhile, 6 to 8 of each LED package 110 are connected in series to form one LED string, and a plurality of LED strings st1 to st6 are connected in parallel with respect to the connector unit 140 to form one LED array. (100) is achieved.

The plurality of LED strings st1 to st6 are connected to one first signal line 120 to receive a positive voltage, and are respectively connected to a plurality of second signal lines 130 to receive a negative voltage. That is, assuming that each LED string st1 to st6 is one LED package, the first signal wiring 120 can be viewed as an anode wiring connected to the anode electrode of the LED package, and the second signal wiring 130 is It can be seen as a cathode wiring connected to the cathode electrode.

That is, the LED strings st1 to st6 have a structure connected to one anode wire and a plurality of cathode wires. Accordingly, each of the LED strings st1 to st6 is a separate cathode wiring and is connected to the second signal wiring 130 having different lengths. The first signal wiring 120 is connected in a branched form for each LED string st1 to st6 by forming one wiring parallel to the longitudinal direction of the LED substrate 115 , and the second signal wiring 130 is Each LED string (st1 ~ st6) is independently connected.

In particular, the LED array 100 according to the embodiment of the present invention is characterized in that the thickness of the second signal wiring 130 increases in proportion to the distance spaced apart from the connector unit 140 .

Specifically, as the connector unit 140 is disposed on one side of the LED board 115, the distance from each LED string st1 to st6 is different, so that the length of the second signal wiring 130 is changed. Accordingly, a voltage deviation (ΔVf) due to the IR drop occurs. In order to improve this problem, the LED array 100 according to the embodiment of the present invention has a first area A/ in which the first signal wiring 120 and the LED strings st1 to st6 are disposed on the LED substrate 115 . A) and the thickness of the second signal line 130 in the second area B/A among the second area B/A in which the second signal line 130 is disposed in consideration of the voltage deviation ΔVf to decide That is, in the present invention, as the distance between the connector unit 140 and the LED strings st1 to st6 increases in the LED array 100 , the thickness of the second signal wiring 130 increases.

In the LED substrate 115 , the first area A/A and the second area B/A may be formed to have a width of about 2.8 mm and 5.6 mm, respectively.

Hereinafter, a structure of an LED array according to an embodiment of the present invention will be described in more detail with reference to an enlarged view of a partial region of FIG. 2 .

3A to 3C are enlarged views of portions P1 to P3 of FIG. 2 .

3A is an enlarged view of a region P1 where the connector unit 140 and the first and second signal wirings 120 and 130 are connected. Referring to FIG. 3A , one side of the LED board 115 is shown in FIG. The first signal wiring 120 and the plurality of third signal wirings 130 are disposed and electrically connected to the connector unit 140 .

The first signal wiring 120 serves to transmit the anode voltage applied to each string, is formed on the first area A/A, and is connected to the first signal line 120 of the connector unit 140 through the connection line L1. It is electrically connected to the connect pad 141 .

The plurality of second signal wires 130 serves to transmit the cathode voltage applied to each string, and is divided into six LED strings and six wires 131 to 136 electrically connected to each other. Most of these second signal wires 130 are formed on the second region B/A, and are connected to the second connect pads 142 to 147 of the connector unit 140 through connection wires L2 to L7. do.

The connector unit 140 is connected to an external driving driver (not shown) to supply a driving voltage to the first and second signal lines, and includes a plurality of connector pads 141 to 149 . Each of the plurality of connect pads 141 to 149 is applied with an anode voltage and a cathode voltage supplied to the LED package, and other driving voltages and ground voltages for driving the LED array. In the drawing, an anode voltage is applied to the first connect pad 141 , a cathode voltage is applied to the second to seventh connect pads 142 to 147 , and the eighth connect pad 148 is one of the connection structures in a floating state. An example is shown, and the connection structure between each wire and the pad is not limited thereto.

In this structure, the first and second signal wirings 120 and 130 are formed in parallel with the longitudinal direction of the LED substrate 110 , and the connector unit 140 is vertically formed in a convex shape of the LED substrate 110 . As it is formed, the connecting wirings L1 to L7 must be connected to the first and second signal wirings 120 and 130 in a bent form, and in the drawing, an example of a structure connected in a bent form twice or more through a contact point represents

Here, each of the connecting wires L1 to L7 may have a thickness of 0.1 mm to 0.15 mm, respectively. In addition, the first to sixth wirings 131 to 136 of the second signal wiring connected to the connecting wirings L2 to L7 are 0.1 mm to 0.15 mm (131), 0.1 mm to 0.15 mm (132), and 0.2 mm, respectively. ~ 0.4 mm (133), 0.2 mm ~ 0.6 mm (134), 0.2 mm ~ 0.85 mm (135), and may be formed to a thickness of 0.2 mm ~ 1.8 mm (136).
Specifically, when it is assumed that the plurality of LED strings st1 to st6 consists of first to sixth LED strings st1 to st6 sequentially spaced apart from the connector unit 140, the first wiring 131 . is connected to the first LED string st1 closest to the connector unit 140 among the plurality of LED strings st1 to st6. In addition, the second wiring 132 is connected to the second LED string st2 adjacent to the connector unit 140 after the first LED string st1.
As shown in FIG. 3A , the first wiring 131 and the second wiring 132 are arranged in parallel with the third to sixth wirings 133 to 136 . Accordingly, the first wiring 131 and the second wiring 132 may be formed to have a relatively small thickness of 0.1 mm to 0.15 mm.
In addition, in a partial area adjacent to the first LED string st1 and the second LED string st2 of the second area B/A, the remaining third to second wirings 131 and 132 are excluded. The six wirings 133 to 136 may have a thickness of 0.2 mm to 0.4 mm greater than that of the first and second wirings 131 and 132 .
As shown in FIG. 3B , in a partial area adjacent to the third LED string st3 of the second area B/A, the remaining fourth to third wirings 131 to 133 are excluded. 6 wirings 134 to 136 are arranged in parallel with each other. That is, in a partial area adjacent to the third LED string st3 of the second area B/A, unlike a partial area adjacent to the second LED string st2 , the third wiring 133 is not disposed, and thus the third wiring 133 is not disposed. Extra width is generated in area 2 (B/A). Accordingly, the fourth to sixth wirings 134 to 136 in a partial area adjacent to the third LED string st3 of the second area B/A are larger than a partial area adjacent to the second LED string st2. It may have a thickness of 0.4 mm to 0.6 mm.
Similarly, in a partial area adjacent to the fourth LED string st4 of the second area B/A, the remaining fifth and sixth wirings excluding the first, second, third, and fourth wirings 131 to 134 . (135~136) are arranged side by side. The fifth and sixth wirings 135 to 136 in a partial area adjacent to the fourth LED string st4 among the second area B/A are 0.6 mm larger than in a partial area adjacent to the third LED string st3. It can be made to a thickness of ~ 0.85 mm.
And, as shown in FIG. 3C , only the sixth wiring 136 is disposed in a partial area adjacent to the fifth LED string st5 of the second area B/A. Accordingly, one end of the sixth wiring 136 connected to the sixth LED string st6 may have a thickness of 1.8 mm or less.

According to this structure, in the LED array of the present invention, the thickness of the second signal line connected to the cathode end of the LED string is determined according to the position of the LED string, so that the voltage deviation ΔVf can be minimized.

On the other hand, the first signal wiring 120 is branched in the middle and connected to a plurality of pads to which the anode electrode of the LED package is bonded, and one pad 120P is shown in FIG. 3A . In addition, the second signal wiring 130 is connected to a pad to which the LED package is bonded at an end thereof, and FIG. 3A shows a pad 131p connected to the first wiring 131 .

Hereinafter, a wiring structure in another area of an LED array according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 3B is an enlarged view of region P2 of FIG. 3 , and referring to FIG. 3B , indicates the end of the third LED string ( st2 of FIG. 2 ).

As shown, in the same manner as in the P2 region, the first signal wiring 120 is branched and bent so that the LED package can be bonded, and is connected to the pad 123P at an end thereof. In addition, a front end pad 132P is formed opposite to the pad 123P and electrically connected to a third line (not shown) of the second signal line.

In addition, the third to sixth wires 133 to 136 of the second signal wire 130 pass through the second region, and the third wire 133 moves upward and is connected to the pad 133P. Accordingly, a space in which the fourth to sixth wirings 134 to 136 of the second signal wiring 130 in the second region can be formed is further secured. Accordingly, in the portion A, the thickness of the third to sixth wirings 133 to 136 is 0.370 mm to 0.390 mm, and in the B portion, the thickness of the fourth to sixth wirings 134 to 136 is 0.545 mm to 0.545 mm. It is formed to 0.0565 mm.

FIG. 3C is an enlarged view of region P3 of FIG. 3 , and referring to FIG. 3C , indicates the end of the fifth LED string ( st5 of FIG. 2 ).

As shown, the first signal wiring 120 is branched and bent so that the LED package can be bonded, is connected to the pad 124P at the end thereof, faces the pad 124P, and is the third of the second signal wiring. A front end pad 134P electrically connected to a wiring (not shown) is formed.

In addition, the fifth and sixth wirings 135 and 136 of the second signal wiring 130 pass through the second region, and the fifth wiring 135 moves upward and is connected to the pad 135P. . A cathode electrode of an LED package included in a corresponding LED string is bonded to the pad 135P, and a pad 135P1 of an anode electrode bonded to the pad 135P is disposed opposite to the pad 135P.

In addition, only the sixth wiring 136 of the second signal wiring 130 is formed in the second region, so that the space for the sixth wiring 136 is maximally secured. Therefore, as the second region is 5.6 mm, the sixth wiring 136 is formed to have a maximum width of less than 5.6 mm in consideration of the minimum separation distance between the wirings.

Hereinafter, a liquid crystal display including an LED array according to an embodiment of the present invention will be described with reference to the drawings.

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

Referring to FIG. 4 , a liquid crystal display 200 according to an embodiment of the present invention includes a liquid crystal panel 210 displaying an image, an LED array 220 including a plurality of LED packages 221 , and an optical member. It includes (230, 232) and the mechanism structures (230, 235) for coupling them.

The liquid crystal panel 210 is composed of a liquid crystal layer interposed therebetween, in which two substrates are bonded by being spaced apart from each other by a predetermined distance. Of the two substrates, the lower substrate is larger than the upper substrate, and the driving IC 215 is mounted on the non-overlapping area. A plurality of pixels are defined in the liquid crystal panel 210 , and by adjusting the light transmittance of each pixel according to an image signal, an image is displayed through the light emitted from the LED array 220 .

The LED array 220 includes a plurality of LED packages 221 , and is mounted on a straight substrate 225 to form a plurality of LED strings. In particular, in the LED array 220 according to the embodiment of the present invention, in proportion to the distance between the mounted LED string and the connector part 224, the thickness of the signal wiring connected to the cathode electrode of the LED string is determined, The voltage deviation (ΔVf) between strings is minimized.

In addition, as the light emitting surface of the LED array 220 , the light guide plate 230 guides the emitted light toward the liquid crystal panel 210 , and the light is provided between the liquid crystal panel 210 and the light guide plate 230 and guided therefrom. It includes an optical sheet 232 made of one or more diffusion sheets and prism sheets for diffusing and condensing the light.

In addition, the liquid crystal panel 210 is mounted on the guide panel 242, the LED array 220 and the light guide plate 230 are mounted on the bottom surface of the cover bottom 235, the guide panel 242 and the cover As the bottom 235 is combined, one liquid crystal display 200 is formed.

According to the above structure, in the liquid crystal display 200 of the present invention, the voltage deviation (ΔVf) according to the length of the signal wiring formed in the LED array 220 is minimized, and the problem of local heating of the LED array 220 and It is possible to improve the luminance deviation problem.

Although preferred embodiments of the present invention have been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom.

100: LED array 110: LED package
115: LED substrate 120: first signal wiring
130: second signal wiring 140: connector part
A/A: first area B/A: second area
st1 to st6: first to sixth LED strings

Claims (8)

It includes a plurality of LED packages connected in series, a plurality of LED strings arranged in a line;
a first signal line connected in parallel to a first end of the plurality of LED strings;
and a plurality of second signal wires respectively connected to second ends of the plurality of LED strings,
The plurality of LED strings are disposed in a first region of the substrate and include first, second and third LED strings adjacent to each other,
The first LED string is closest to the connector part,
The second LED string is disposed between the first LED string and the third LED string and is spaced apart from the connector part further than the first LED string,
The third LED string is spaced apart from the connector part further than the second LED string,
the plurality of second signal wires are disposed in a second region of the substrate;
Among the plurality of second signal wires, any two connected to the first and second LED strings have a first thickness,
In a partial region adjacent to the first LED string and the second LED string in the second region, second signal wirings remaining except for any two connected to the first and second LED strings among the plurality of second signal wirings are made of a second thickness greater than the first thickness,
In a partial region adjacent to the third LED string among the second regions, second signal wirings other than any three connected to the first, second, and third LED strings among the plurality of second signal wirings are An LED array comprising a third thickness greater than two thicknesses. The method of claim 1,
The first and second signal wires are
An LED array to which the anode voltage and the cathode voltage of the LED package are applied, respectively. The method of claim 1,
The plurality of LED strings is an LED array arranged in a line on a straight LED substrate. 4. The method of claim 3,
The plurality of LED strings is an LED array including 6 to 8 LED packages, respectively. 5. The method of claim 4,
It further includes a plurality of connection wires connected between each of the plurality of second signal wires and a pad of the connector part and bent at least twice in a vertical direction,
The plurality of second signal wiring is an LED array arranged in parallel with the longitudinal direction of the LED substrate. The method of claim 1,
The first thickness is 0.1 mm to 0.15 mm,
The second thickness is 0.2 mm to 0.4 mm,
The third thickness of the LED array is 0.4 mm ~ 0.6 mm or less. 6. The method of claim 5,
One end of the second connecting wire connected to the LED string farthest from the connector part among the plurality of LED strings is made of a thickness of 1.8 mm or less. An LED array according to any one of claims 1 to 7;
an optical member disposed on the light emitting surface of the LED array;
a liquid crystal panel disposed on the optical member and displaying an image with light emitted from the LED array; and
A liquid crystal display device including a mechanical structure on which the liquid crystal panel and the LED array are mounted.

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