KR20130019853A - Backlight unit - Google Patents

Abstract

PURPOSE: A backlight unit is provided to improve the degree of freedom of the backlight unit by separating a light source part from a bottom cover. CONSTITUTION: A bottom cover(1011) includes an accommodating part(1012). A light guide plate(1041) is arranged on the bottom cover. A light source part(100) is separated from the bottom cover. A light transmission part(200) transmits the light of the light source part to the light receiving part of the light guide plate. The light transmission part includes multiple optical fibers(211).

Description

Backlight unit {BACKLIGHT UNIT}

An embodiment relates to a backlight unit.

Light emitting diodes (LEDs) are a type of semiconductor device that converts electrical energy into light. Light emitting diodes have the advantages of low power consumption, semi-permanent life, fast response speed, safety and environmental friendliness compared to conventional light sources such as fluorescent and incandescent lamps. Accordingly, much research has been conducted to replace an existing light source with a light emitting diode, and a light emitting diode has been increasingly used as a light source for various lamps used in indoor / outdoor, a liquid crystal display, a display board, and a streetlight.

The embodiment provides a backlight unit in which a light source unit is spaced apart from a bottom cover in which a new light guide plate is accommodated.

The embodiment provides a backlight unit including a light transmission unit between a bottom cover in which the light guide plate is accommodated and a light source unit.

According to an embodiment, a backlight unit may include: a bottom cover having a housing; A light guide plate arranged on the bottom cover; A light source unit spaced apart from the bottom cover to provide light; And a light transmission unit configured to transfer the light provided from the light source unit to the light incident unit of the light guide plate, and the light transmission unit includes a plurality of optical fibers.

In an embodiment, local dimming may be performed in the display device.

The embodiment may improve the degree of freedom of the backlight unit by separating the light source from the bottom cover.

The embodiment can improve the heat radiation efficiency of the light source unit.

The embodiment has the effect of easy replacement of the light source unit.

The embodiment can improve the reliability of the light emitting device and the light unit having the light emitting device.

1 is a perspective view of a display device according to an exemplary embodiment.
FIG. 2 is a diagram illustrating an example of the light source unit and the light transmitting unit of FIG. 1.
3 is a view illustrating coupling the light guide plate and the optical fiber of FIG. 1.
4 is a diagram illustrating an example in which light of the light guide plate of FIG. 1 is incident.
5 is a view illustrating another example of coupling the light guide plate and the optical fiber of FIG. 1.

In the description of the embodiments, each layer, region, pattern, or structure is formed “on” or “under” of a substrate, each layer (film), region, pad, or pattern. In the case where it is described as, “on” and “under” include both “directly” or “indirectly” formed through another layer. In addition, the criteria for above or below each layer will be described with reference to the drawings. The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size of each component does not entirely reflect the actual size.

Hereinafter, a display device according to an exemplary embodiment will be described with reference to the accompanying drawings.

1 is a perspective view of a display device according to an exemplary embodiment.

Referring to FIG. 1, the display device 1000 includes a plurality of light guide plates 1041, a reflective member 1022 under the light guide plate 1041, an optical sheet 1051 on the light guide plate 1041, and the optical sheet. The bottom cover 1011 in which the display panel 1061, the light guide plate 1041, and the reflecting member 1022 are housed, the light source unit 100 that emits light, and the light of the light source unit 100 are disposed on the display panel 1061. The light transmitting unit 200 may include, but is not limited to.

The bottom cover 1011, the light source unit 100, the light transmission unit 200, the reflective member 1022, the light guide plate 1041, and the optical sheet 1051 may be defined as a light unit 1050.

The bottom cover 1011 may be formed of a metal material, for example, a metal having good thermal conductivity. For example, the bottom cover 1011 may include aluminum (Al), magnesium (Mg), zinc (Zn), titanium (Ti), tantalum (Ta), Hafnium (Hf), niobium (Nb) may be selectively formed from an alloy of any one of the above metals.

A reflecting member 1022 may be disposed in the accommodating portion 1012 of the bottom cover 1011, and the reflecting member 1022 reflects light leaked to lower surfaces of the plurality of light guide plates 1041. By supplying to 1061, the luminance of the display panel 1061 can be improved. The reflective member 1022 may be formed of, for example, PET, PC, or PVC resin, but is not limited thereto. The reflective member 1022 may be a reflective layer formed on an upper surface of the bottom cover 1011, but is not limited thereto.

The plurality of light guide plates 1041 may serve to diffuse a light provided from the light transmitting part 200 to make a surface light source. The light guide plate 1041 is made of a transparent material, for example, acrylic resin-based such as polymethyl metaacrylate (PMMA), polyethylene terephthlate (PET), polycarbonate (PC), cycloolefin copolymer (COC), and polyethylene naphthalate (PEN). It may include one of the resins.

The plurality of light guide plates 1041 may be arranged in a matrix form (N * M, N, M is an integer of 2 or more), 1 * M, or N * 1 in the bottom cover 1011. The number and individual areas of the light guide plate 1041 may be variously changed as necessary, and a partial driving area, a degree of light loss, and an appearance may be considered. In addition, although the shape of the light guide plate 1041 is illustrated in a quadrangular shape, it may be implemented in a polygon such as a triangle or a pentagon.

The lower surface of the light guide plate 1041 may be formed with a reflective pattern of a predetermined shape at a predetermined interval, the shape and the interval of such a reflective pattern may be changed within the technical scope of the embodiment.

An optical sheet 1051 is disposed on the light guide plate 1041, and a display panel 1061 is disposed on the optical sheet 1051.

The optical sheet 1051 is disposed between the display panel 1061 and the light guide plate 1041 and includes at least one light transmitting sheet. The optical sheet 1051 may include, for example, at least one of a sheet such as a diffusion sheet, horizontal and vertical prism sheets, a brightness enhanced sheet, and the like. The diffusion sheet diffuses the incident light, the horizontal or vertical prism sheet focuses the incident light onto the display panel 1061, and the brightness enhancement sheet reuses the lost light to improve luminance. Let it be. In addition, a protective sheet may be disposed on the display panel 1061, but is not limited thereto.

The display panel 1061 is, for example, an LCD panel, and includes a first and second substrates of transparent materials facing each other, and a liquid crystal layer interposed between the first and second substrates. A polarizing plate may be attached to at least one surface of the display panel 1061, but the present invention is not limited thereto. The display panel 1061 displays information by transmitting or blocking light provided from the light guide plate 1041. The display device 1000 can be applied to video display devices such as portable terminals, monitors of notebook computers, monitors of laptop computers, and televisions.

An outer side of the bottom cover 1011 includes a light source unit 100 and a light transmission unit 200 for transmitting the light provided from the light source unit 100 into the bottom cover 1011. The light transmitting part 200 protrudes through the hole 1013 of the bottom cover 1011 to the accommodating part 1012 of the bottom cover 1011. The optical fiber 211 disposed in the accommodating part 1012 of the bottom cover 1011 may be disposed on the reflective member 1022 or may be disposed under the reflective member 1022, but is not limited thereto. .

2, the light emitting module 120 is disposed inside the case 113 of the light source unit 100. The light emitting module 120 includes a module substrate 121 and a plurality of light emitting diodes 123. The module substrate 121 is made of a metal core PCB, a FR-4 PCB, a general PCB, a flexible substrate, and the like. Various changes may be made within the technical scope of the embodiment.

The module substrate 121 may be in close contact with the case 111 to dissipate heat generated from the plurality of light emitting diodes 123.

The plurality of light emitting diodes 123 may be mounted on the module substrate 120, and may selectively emit light in a range of ultraviolet light to visible light, for example, at least one of red, blue, green, and white light. Can be. The plurality of light emitting diodes 123 may be an LED chip or a package in which the LED chip is packaged, but is not limited thereto.

The intervals D1 between the plurality of light emitting diodes 123 may be arranged at regular intervals or at irregular intervals.

The plurality of light emitting diodes 123 and the light transmitting unit 200 may be spaced apart at predetermined intervals T1, and may be disposed in close contact with each other, but embodiments are not limited thereto.

A phosphor layer may be disposed in the light emission path of the light emitting diode 123, and the phosphor layer may include a phosphor for changing a wavelength of emitted light, and the phosphor is emitted from the light emitting diode 123. Part of the light is excited to emit light of a different wavelength. The phosphor may be selectively formed from YAG, TAG, Silicate, Nitride, and Oxy-nitride based materials. The phosphor may include at least one of a red phosphor, a yellow phosphor, and a green phosphor, but the present invention is not limited thereto.

The light source unit 100 includes a heat dissipation fan 131 installed in the case interior 113, and the heat dissipation fan 131 subtracts heat generated from the plurality of light emitting modules 120 to the outside, thereby providing the light emitting diode. Do not affect the operation of the (123).

The case 111 may be a broadcast receiving device that outputs a broadcast signal, for example, a set top box, but is not limited thereto.

The light transmitting unit 200 includes a plurality of optical fibers 211, and the optical fibers 211 are surrounded by a core layer made of a transparent glass or plastic fiber that transmits light and a clad layer having a low refractive index. The core layer has a higher refractive index than the cladding layer. The light is totally reflected on the boundary between the core layer and the cladding layer so that the light penetrates the core layer and propagates in the long direction.

The plurality of optical fibers 211 guides and condenses the light incident from the condenser 212 provided at the optical input terminal. The light collecting part 212, which is an optical input end of the optical fiber 211, is formed to have a diameter larger than that of the optical fiber 211, and may effectively receive light.

One light emitting diode 123 may correspond to each of the light collecting units 212, which are optical input terminals of the optical fiber 211, or a plurality of light emitting diodes 123 may correspond to each other. In addition, the optical fiber 211 may receive the reflected light without receiving light directly from each light emitting diode 123. The distance D2 between the optical fibers 211 may be narrower or wider than the distance between the light emitting diodes 123, but is not limited thereto.

The optical fiber 211 may be disposed in one or two or more numbers in each of the light guide plates 1041 of FIG. 1.

Referring to FIG. 3, the optical fibers 211 may be disposed to correspond to the cell regions A1 to A8 of the plurality of light guide plates 1041, respectively. The optical output end of the optical fiber 211 is coupled to correspond to one side of each of the light guide plates 1041, thereby providing light to each of the light guide plates 1041. Accordingly, the light guide plate 1041 guides the incident light and outputs the light to the surface light source.

Each of the optical fibers 211 may have a light output end corresponding to a light incident region of the light guide plates A1 to A8, for example, a central portion of one side or a different region of one side.

Referring to FIG. 4, a reflective pattern 1042 is disposed on a lower surface of the light guide plate 1041, and the reflective pattern 1042 reflects light incident from the light guide plate 1041 toward the upper surface of the light guide plate 1041. Release it.

One or two or more optical fibers 211 may be disposed on one side surface S1 of the light guide plate 1041 in parallel with the light guide plate 1041. In addition, the light output end of the optical fiber 211 may be in contact with one side (S1) of the light guide plate (1041).

Referring to FIG. 5, the light incidence part 411 of the light guide plate 1041 is formed in a stepped structure in a region between one side surface S1 and the bottom surface of the light guide plate 1041, and the light incidence part 411 of the stepped structure is formed. The optical fiber 211 is disposed correspondingly. The optical fiber 211 may be disposed in an inclined form with respect to the lower surface of the light guide plate 1041 so that the optical fiber 211 may not be bent. When the optical fiber 211 is bent, a defect may occur, so that the optical fiber 211 corresponds to the light incident part 411 of the light guide plate 1041 in a curved or oblique shape. An adhesive tape or a fastening member for fixing the position of the optical fiber 211 may be further disposed in the bottom cover, but is not limited thereto.

As described above, the backlight unit 1050 may be an edge type that receives light incident on the optical fiber 211 and enters the side of the light guide plate 1041.

1 and 2, the plurality of light emitting diodes 123 may be selectively driven to provide light for each area of the light guide plate 1041. When the plurality of light emitting diodes 123 are driven by a local dimming method, the plurality of light emitting diodes 123 may be adjusted by stars of the plurality of light guide plates 1041, and thus light may be adjusted by stars of the light guide plate 1041.

The plurality of light emitting diodes 123 may be driven in an impulsive manner. In this case, each of the driving regions may be sequentially turned on in synchronization with the display panel 1061.

The light guide plate 1041 may be divided into multiple regions to realize low power consumption, and the gap between the boundaries of the light guide plate 1041 may be reduced to obtain light loss and a uniform appearance. In addition, uniform appearance quality and luminance may be improved.

In addition, by installing the light source unit 100 outside the bottom cover 1011, the width of the housing portion of the bottom cover 1011 and the overall width of the plurality of light guide plates 1041 may be the same. In addition, it is possible to improve the design freedom in the bottom cover 1011.

By disposing the light source unit 100 outside the bottom cover 1011, the light source unit 100 may be easily replaced.

In addition, by disposing the light source unit 100 outside the bottom cover 1011, unnecessary side regions of the display device may be minimized.

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. Furthermore, the features, structures, effects, and the like illustrated in each embodiment 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.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

1000: display device, 100: light source unit, 120: light emitting module, 121: module substrate, 123: light emitting diode, 131: heat dissipation fan, 200: light transmitting unit, 211: optical fiber, 1011: bottom cover, 1022: reflective member, 1041: Light guide plate, 1051: Reflective sheet, 1061: Display panel

Claims (11)

A bottom cover having a housing;
A light guide plate arranged on the bottom cover;
A light source unit spaced apart from the bottom cover to provide light;
It includes a light transmission unit for transmitting the light provided from the light source unit to the light incident portion of the light guide plate,
The light transmitting unit includes a plurality of optical fibers. The backlight unit of claim 1, wherein the plurality of light guide plates are arranged in a matrix. The light emitting device of claim 1, wherein the light source unit comprises: a plurality of light emitting diodes providing light to each of the plurality of optical fibers; And a module substrate on which the plurality of light emitting diodes are mounted. The backlight unit of claim 3, wherein the light source unit comprises a case having the plurality of light emitting diodes and a module substrate. The backlight unit of claim 4, wherein the light source unit comprises a heat dissipation fan installed in the case. The backlight unit of claim 3, wherein the optical fibers are disposed at each side of the plurality of light guide plates. The backlight unit of claim 3, further comprising a reflective pattern on a lower surface of each of the light guide plates. The backlight unit of claim 3, wherein one or two optical fibers are disposed in each of the light guide plates. The backlight unit of claim 3, further comprising a light collecting unit configured to guide light emitted from the light emitting diode to an optical input terminal of each optical fiber. The backlight unit of claim 3, wherein the light incident portion of the light guide plate is a stepped region between one side surface and a bottom surface of the light guide plate. The backlight unit of claim 4, wherein the light source unit directly or reflects the light emitted from the light emitting diode to provide the optical fiber.

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