KR20110021315A - Backlight unit and display device having same - Google Patents

Abstract

An embodiment relates to a backlight unit and a display device having the same.

The backlight unit according to the embodiment, the light guide plate; An edge type first light emitting part including a plurality of light emitting diodes disposed on at least one side of the light guide plate; And a direct type third light emitting unit including a plurality of light emitting diodes disposed in a lower region of the light guide plate.

Description

BACKLIGHT UNIT AND DISPLAY APPARATUS HAVING THEREOF}

An embodiment relates to a backlight unit and a display device having the same.

In today's information society, display elements are more important than ever as visual information transfer media. The flat panel display device includes a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an electroluminescence (EL). Most are commercially available and commercially available. In particular, the liquid crystal display has advantages of high image quality and low power consumption, and has recently been rapidly developed in size and high resolution due to the recent mass production technology and R & D.

In the liquid crystal display, two substrates on which the field generating electrodes are formed are disposed so that the surfaces on which the two electrodes are formed face each other, and a liquid crystal material is injected between the two substrates. Then, the liquid crystal molecules are moved by the electric field generated by applying a voltage to the two electrodes, thereby representing the image by the transmittance of light that varies accordingly. However, the liquid crystal display does not emit light by itself and merely adjusts a light transmittance, and thus requires a separate light source. Accordingly, an image is displayed by arranging a backlight under the liquid crystal display panel and injecting light from the backlight into the liquid crystal display panel to adjust the amount of light according to the arrangement of liquid crystals.

Such backlight is divided into a direct method of directly dimming the front surface of the substrate by placing a lamp, which is a light source, on the bottom of the liquid crystal panel, and a side method of reflecting and diffusing light by a light guide plate and a reflecting plate by placing the lamp on one or both sides of the liquid crystal panel. Lose.

The direct method does not need a light guide plate because the light emitted from the lamp is directly emitted to the front of the liquid crystal panel, whereas the side method requires a light guide plate that emits the light emitted from the side lamp to the front of the backlight. In general, the backlight used in the notebook computer adopts a side method with less luminance unevenness, a thin film type, and low power consumption.

The embodiment provides a backlight unit in which an edge type light emitting unit and a direct type light emitting unit are mixed, and a display device having the same.

The embodiment provides a backlight unit including an edge type main light emitting part and a direct type sub light emitting part, and a display device having the same.

The embodiment provides a backlight unit including a direct type main light emitting part and an edge type sub light emitting part, and a display device having the same.

The embodiment provides a backlight unit including an edge type light emitting unit and a dimming light emitting unit, and a display device having the same.

The backlight unit according to the embodiment, the light guide plate; An edge type first light emitting part including a plurality of light emitting diodes disposed on at least one side of the light guide plate; And a direct type third light emitting unit including a plurality of light emitting diodes disposed in a lower region of the light guide plate.

According to an exemplary embodiment, a display device may include a light guide plate; An edge type first light emitting part including a plurality of light emitting diodes disposed on at least one side of the light guide plate; A second direct light emitting part including a plurality of light emitting diodes disposed under the light guide plate; At least one optical sheet on the light guide plate; And a display panel on the optical sheet.

The embodiment can provide a backlight unit employing fewer LEDs than a direct type.

The embodiment can reduce light loss and improve luminance uniformity.

According to the embodiment, the local dimming may be expressed by mixing the edge type light emitting part and the direct type light emitting part.

According to the embodiment, the number of LEDs of the edge type light emitting part may be reduced, and the heat radiation of the direct type light emitting part may be effectively performed.

In the description of an embodiment, each layer (film), region, pattern, or structure is formed “on” or “under” a substrate, each layer (film), region, pad, or pattern. In the case where it is described as "to", "on" and "under" include both "directly" or "indirectly" formed. Also, the criteria for top, bottom, or bottom of each layer will be described with reference to the drawings.

In the drawings, the thickness or size of each layer is exaggerated, omitted, or schematically illustrated for convenience and clarity of description. In addition, the size of each component does not necessarily reflect the actual size.

Hereinafter, with reference to the accompanying drawings as follows.

1 is a perspective view illustrating a display device according to a first embodiment, and FIG. 2 is a side cross-sectional view of the backlight unit of FIG. 1.

1 and 2, the display apparatus 100 includes a first light emitting unit 110, a second light emitting unit 115, a third light emitting unit 120, a light guide plate 130, an optical sheet 140, The reflective plate 150 and the display panel 101 are included.

The first light emitting unit 110, the second light emitting unit 115, the third light emitting unit 120, the light guide plate 130, the optical sheet 140, and the reflective plate 150 are connected to the backlight unit 105. Can be defined.

The first light emitting unit 110 includes a first substrate 111 and a plurality of first light emitting diodes 113 and is disposed on one side of the light guide plate 130. A plurality of first light emitting diodes 113 are mounted in at least one row on the first substrate 111. The plurality of first light emitting diodes 113 may be arranged at regular intervals, at irregular intervals, and at different intervals for certain regions / sections.

The second light emitting unit 115 includes a second substrate 116 and a plurality of second light emitting diodes 118 and is disposed on the other side of the light guide plate 130. A plurality of second light emitting diodes 118 are mounted in at least one row on the second substrate 116. The plurality of second light emitting diodes 118 may be arranged at regular intervals, at irregular intervals, and at different intervals for certain regions / sections. The first light emitting diode 113 and the second light emitting diode 118 may be arranged to face each other or may be arranged to be offset from each other.

In the first light emitting diode 116 and the second light emitting diode 118, a first interval of a center section may be greater than a second interval of a side section on both sides of the light guide plate 130. It may be changed by the arrangement area of the light emitting unit 120.

The light guide plate 130 guides the light incident from the first light emitting unit 110 and / or the second light emitting unit 115 disposed on at least one side to be uniformly transmitted to the display panel 101 as a surface light source. It plays a role.

Under the light guide plate 130, a dot or V-shaped groove pattern made through a printing method may be formed to diffuse light to form a uniform surface light source, and such a structure may improve light diffusion function and brightness. And the like, but are not limited thereto.

V-shaped groove patterns, polygonal patterns, hemispherical patterns, or scratches may be formed on both sides of the light guide plate 130, that is, part or all sides of the light-receiving portion, to diffuse the emission light of the first and second light emitting diodes 113 and 118. It may be formed in a columnar shape in the vertical direction.

The light guide plate 130 is formed of a light transmissive material such as polycarbonate or acrylic having a predetermined thickness and is formed to have a size corresponding to that of the display panel 101. There are two types of light guide plate 130, a flat plate type and an inclined type, but are not limited thereto.

The light guide plate 130 converts the light incident from the edge-type first light emitting unit 110 and / or the edge-type second light emitting unit 115 into a surface light source and outputs the light.

The third light emitting unit 120 is disposed under the light guide plate 130. The third light emitting unit 120 includes a third substrate 121 and a plurality of third light emitting diodes 123 to provide a direct light source to the light guide plate 130.

The third light emitting unit 120 may be disposed in a predetermined area of the light guide plate 130, for example, near the center A0 or in the center area A1 of FIG. 2. The third light emitters 120 may be disposed at corners of the light guide plate 130 instead of the center area A1, but the present invention is not limited thereto. The third light emitting unit 120 is disposed in an area (A1 of FIG. 2) capable of compensating for the light distribution emitted from the first light emitting unit 110 and the second light emitting unit 115. The interval between the light emitting diode 113 and the second light emitting diode 118 may be wider than the side section of the light guide plate 130.

Accordingly, since the edge type and the direct type are mixed in the first to third light emitting diodes 113, 118 and 123, the first to third light emitting diodes 113, 118 and 123 may be reduced rather than the number of light emitting diodes applied to the backlight unit.

Here, the third light emitting unit 120 is disposed in the center section of the light guide plate 130, and the luminance uniformity of the light emitted to the center section of the first light emitting unit 110 and the second light emitting unit 115. I can keep it.

The plurality of third light emitting diodes 123 of the third light emitting unit 120 may be selectively turned on / off to express a part or the whole of the center area by local dimming.

The third substrate 121 of the third light emitting unit 120 may be in direct contact with the bottom cover, so that heat radiation may be effectively performed.

The first to third light emitting diodes 113, 118 and 123 may emit white light or emit light of at least one color (red / green / blue), and the first and second light emitting diodes 113 and 118 may emit light. ) May arrange LEDs of a multi-color color (Red / Blue / Green), and the third light emitting diode 123 may arrange a white LED, and may be disposed in a reverse configuration thereof. The configuration of such LED may be variously changed within the technical scope of the embodiment.

An interval T1 between the light guide plate 130 and the third light emitting unit 120 may be spaced apart from each other by a distance at which the light emitted from the third light emitting diode 123 may be diffused.

The reflective plate 150 may be disposed under the light guide plate 130. The reflective plate 150 reflects the light leaking downward from the light guide plate 130 to prevent light loss. The reflective plate 150 may be a sheet member that is hardly reflective such as a white polyethylene terephthalate (PET) film, or a sheet member that is positively reflective such as silver foil, but is not limited thereto.

An arrangement position of the reflective plate 150 is disposed under the third light emitting unit 120, and the light leaked below the light guide plate from the light emitted from the first to third light emitting diodes 113, 118, and 123 is disposed on the light guide plate. 130 may be reflected.

At least one optical sheet 140 may be disposed on the light guide plate 130. The optical sheet 140 may include at least one of a prism sheet, a diffusion sheet, and a brightness enhancement sheet. The prism sheet may include a horizontal and / or vertical prism sheet, and may refract and collect incident light into a display area, and the diffusion sheet may diffuse the incident light. In addition, a protective sheet may be disposed on the optical sheet 140, and the protective sheet protects sheets sensitive to dust and scratches and also prevents flow of the sheets when only the backlight unit is transported.

The display panel 101 is disposed on the optical sheet 140, and the display panel 101 includes a liquid crystal display panel. The display panel 101 displays information using light transmitted through the optical sheet 140.

The embodiment can provide a backlight unit employing a smaller number of light emitting diodes than the direct type, and can reduce light loss and improve luminance uniformity. In addition, the direct light emitter 120 may be disposed to express local dimming. In addition, the number of LEDs of the edge type light emitting parts 110 and 115 may be reduced, and heat radiation of the direct type light emitting part 120 may be effectively performed.

3 is a diagram illustrating a modification of FIG. 2. In the description of FIG. 2, the same parts as those of FIG. 2 are denoted by the same reference numerals, and reference will be made to FIG. 2.

Referring to FIG. 3, the backlight unit 105A forms a plurality of diode holes 151 in the reflection plate 150, and the light emitting diodes 123 of the third light emitting part 120 are formed in the diode holes 151. ) Is inserted and protrudes.

The reflective plate 150 may effectively reflect light leaking from the light guide plate 130.

In addition, a diode hole of the reflective plate 150 is disposed around the outer circumference of the third light emitting diode 123 to prevent the light emitted from the third light emitting diode 123 from being dispersed to the periphery and toward the panel. You can guide them to proceed. The diode hole 151 is formed in a circular columnar shape with a lower diameter and a wider upper diameter, thereby effectively guiding light emitted from the third light emitting diode 123.

4 is a diagram illustrating a modified example of FIG. 3. In the description of FIG. 4, the same parts as in FIG. 3 are referred to with reference to FIG. 3, and redundant descriptions thereof will be omitted.

Referring to FIG. 4, the backlight unit 105B includes a light dispersing member 155 between the third light emitting unit 120 and the light guide plate 130. The light dispersing member 155 may optionally include a light dispersing lens, a diffusing agent, and / or a light dispersing sheet, and may disperse the light incident from the third light emitting part 120 to prevent hot spots. have. The light dispersing member 155 may be formed in a lens shape or a structure or sheet coated with a diffusing agent under the light guide plate 130.

The light dispersing member 155 may be disposed for each dimming area of the third light emitting part 120 to prevent light leakage due to dimming.

By disposing the light dispersing member 155 between the third light emitting unit 120 and the light guide plate 130, the thickness of the backlight unit 105B may be improved than that of the direct type backlight unit.

5 to 12 are plan views illustrating modified examples of the light emitting unit in the backlight unit according to the embodiment. In the description, the same parts as those of FIG. 2 are referred to with reference to FIG. 2, and descriptions thereof will not be repeated.

Referring to FIG. 5, first and second light emitting units 110 and 115 are disposed on both sides of the light guide plate 130, and the first light emitting diode 113 and the second light emitting unit 115 of the first light emitting unit 110 are disposed. The second light emitting diodes 118) are arranged at regular intervals and arranged to face each other.

 The third light emitting unit (120 of FIG. 2) is disposed in at least one module in the center area A1 under the light guide plate 130, and the third light emitting diode 123 of the third light emitting unit (120 of FIG. 2). May be disposed in the local dimming area A11 of the center area A1, respectively. Here, the size of the third light emitting part may be formed to be equal to the sum of the local dimming areas.

Referring to FIG. 6, the first light emitting unit 110 is disposed on one side of the light guide plate 130, and the first light emitting diode 113 of the first light emitting unit 110 is disposed in the Y-axis direction of the light guide plate 130. It can be arranged at different intervals. The interval between the first light emitting diode 113 is greater than that of the center sections L1 of the light guide plate 130 than the side sections L2 and L3, thereby reducing the number of light emitting diodes due to the mixing of the direct type. have.

The third light emitting diode 123 of the third light emitting unit is disposed in the center area A2 of the light guide plate 130 to compensate for the light efficiency of the center section L1 of the first light emitting unit 110. Can be. The third light emitting diode 123 of the third light emitting unit may be selectively driven to be implemented as a plurality of local dimming regions A12.

The center section L1 of the first light emitting unit 110 has the same length as the sum L1 = L2 + L3 of both side sections L2 and L3, and the light uniformity and the brightness uniformity in the mixed light source structure. Can improve.

FIG. 7 illustrates a structure in which the first light emitting unit 110 is arranged in the X-axis direction from the structure of FIG. 6. In this configuration, when the length of the X-axis direction and the Y-axis direction is different according to the size of the light guide plate 130, the first light emitting unit 110 is disposed in a relatively long Y-axis direction or a short X-axis direction, and the light guide plate 130 is disposed. The third light emitting part is disposed under the center area A3 of the bottom side. The local dimming area A13 may be expressed using the plurality of third light emitting diodes 123 of the third light emitting unit.

Referring to FIG. 8, the first light emitting unit 110 and the second light emitting unit 115 are disposed on both sides of the light guide plate 130, and the first light emitting diode 113 and the first light emitting unit 110 of the first light emitting unit 110 are disposed. The second light emitting diode 118 of the second light emitting unit 115 has a center section L1 disposed at a wider interval than the side sections L2 and L3 of the light guide plate 130, and thus has a direct structure in the mixed light source structure. The number of light emitting diodes can be reduced.

The third light emitting unit 120 may be disposed in the center area A4 corresponding to both center sections L1 of the light guide plate 130 to compensate for light efficiency.

The third light emitting diode 123 of the third light emitting unit disposed under the center area A4 of the light guide plate 130 may be selectively turned on or off for local dimming.

Referring to FIG. 9, the first and second light emitting parts 110 and 115 are disposed on both sides of the light guide plate 130, and the center section L11 of the first and second light emitting parts 110 and 115 may include a side section L12, It can be allocated at least twice as large as the sum of L13). The center section L11 of the first and second light emitting units 110 and 115 may have a larger spacing of the light emitting diodes than the side sections L12 and L13.

The center area A5 of the light guide plate 130 may be divided into a plurality of dimming areas A15 by the third light emitting diode 123 of the third light emitting part, and the plurality of dimming areas A15 may be M * N. The area M may be formed along the center section L11, and the area N may be formed in at least one column according to the width D1 of the center section. That is, by taking the center section L11 of the light guide plate 130 relatively long, the dimming area using the third light emitting part 120 may be further subdivided and implemented in a wider area.

Referring to FIG. 10, edge-shaped first and second light emitting units 110 and 115 are disposed on both sides of the light guide plate 130, and the first light emitting diode 113 and the second light emitting unit of the first light emitting unit 110 are disposed. The second light emitting diodes 118 of the unit 115 may correspond to each other, and may be disposed at equal equal intervals on both sides of the light guide plate 130.

The third light emitting diode 123 of the third light emitting part disposed under the light guide plate 130 is directly below the region A6 in the longitudinal direction L14 (edge-shaped arrangement direction) and the width D2 of the light guide plate 130. It is arranged in the form, it can implement a plurality of local dimming area (A16).

Here, the local dimming regions A15 and A16 of FIGS. 9 and 10 may have the same size or different sizes, and the size of the regions may be controlled in a modular manner.

11 and 12, the first and second light emitting parts 110 and 115 are disposed on both sides of the light guide plate 130, and the light emitting diodes are arranged at regular equal intervals. do. Herein, another example structure may be applied to the gap between the light emitting diodes of the first and second light emitting parts 110 and 115, but is not limited thereto.

The third light emitting part disposed below the light guide plate 130 may be disposed in a plurality of module types in the center areas A7 and A7 of the light guide plate 130, and each module may be formed in a polygon such as a rectangle or a triangle. The local dimming areas A17 and A18 may be represented by polygons.

13 is a plan view illustrating a backlight unit according to a second embodiment. In FIG. 13, the same parts as those in the first embodiment are referred to the first embodiment, and redundant description thereof will be omitted.

Referring to FIG. 13, the LEDs 113 and 118 of the light emitting units 110 and 115 are disposed at regular intervals on both side center sections of the light guide plate 130 to implement an edge type light source. In this case, the light emitting diodes 113 and 118 may generate dark portions in the corner regions due to the directivity angle characteristic of the light.

The third light emitting unit 120 is disposed under the corner region of the light guide plate 130 to provide the direct type third light emitting unit 120A with respect to the area not covered by the first and second light emitting units 110 and 115. You can place each one. In this case, the direct type third light emitting unit 120A may be expressed by local dimming.

The backlight unit of the embodiment may be applied to a TV, a monitor, a notebook, and the like.

Features, structures, effects, and the like described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. In addition, the features, structures, effects, and the like illustrated in the embodiments may be combined or modified with respect to other embodiments by those skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

Although the above description has been made with reference to the embodiments, these are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains are not illustrated above without departing from the essential characteristics of the present embodiments. It will be appreciated that many variations and applications are possible. For example, each component specifically shown in the embodiment can be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

1 is a perspective view illustrating a display device according to a first embodiment.

FIG. 2 is a side cross-sectional view illustrating the backlight unit of FIG. 1.

3 and 4 are diagrams showing a modified example of FIG.

5 to 12 are diagrams illustrating a modified example of the light emitting unit of FIG. 2.

14 is a diagram illustrating a backlight unit according to a second embodiment.

Claims (16)

Light guide plate; An edge type first light emitting part including a plurality of light emitting diodes disposed on at least one side of the light guide plate; And And a third light emitting unit of a direct type including a plurality of light emitting diodes disposed in a lower region of the light guide plate. The backlight unit of claim 1, further comprising a reflective plate disposed under the light guide plate. The backlight unit of claim 1, wherein the first light emitting portion is disposed at both sides of the light guide plate. The backlight unit of claim 1, wherein the light emitting diodes of the first light emitting part are disposed at equal intervals on the side surfaces of the light guide plate. 3. The backlight unit of claim 1, wherein the plurality of light emitting diodes of the first light emitting unit are arranged to have a distance in a center section of the light guide plate greater than a gap in both side sections. 4. According to claim 1 or 2, wherein the plurality of light emitting diodes of the first light emitting unit is disposed in the center section of the light guide plate, The third light emitting unit is disposed in the corner area of the light guide plate. The backlight unit of claim 1, wherein the plurality of light emitting diodes of the third light emitting unit are arranged in at least one module type below a center area of the light guide plate. 8. The backlight unit of claim 1, wherein at least one light emitting diode of the third light emitting unit is disposed under a center area of the light guide plate to operate by local dimming. The backlight unit of claim 8, wherein the local dimming area comprises a polygonal shape. The backlight unit of claim 1, further comprising a light dispersing member between the third light emitting portion and the light guide plate. The backlight unit of claim 1, further comprising at least one optical sheet disposed on the light guide plate. The backlight unit of claim 3, wherein both side surfaces of the light guide plate face at least one of a V-shaped groove pattern, a polygonal pattern, a hemispherical pattern, and a scratch facing the light emitting diodes of the first light emitting unit. Light guide plate; An edge type first light emitting part including a plurality of light emitting diodes disposed on at least one side of the light guide plate; A direct type third light emitting unit including a plurality of light emitting diodes disposed under the light guide plate; At least one optical sheet on the light guide plate; And And a display panel on the optical sheet. The display apparatus of claim 13, wherein the display panel comprises a liquid crystal display panel. The display apparatus of claim 13, wherein the plurality of light emitting diodes of the third light emitting part are disposed in a center area or a corner area of the light guide plate and selectively operate by local dimming. The display device of claim 15, wherein the first light emitting parts are disposed at both sides of the light guide plate, and the plurality of light emitting diodes are disposed at equal intervals or at different intervals for each section.

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