KR20060116879A - Light guide unit, back light assembly having the light guide unit and display device having the same - Google Patents

Abstract

A light guiding plate, a backlight assembly having the same, and a display device having the same are provided to reduce the number of constituent components of the light guiding plate, thereby improving the assembling efficiency, by forming a light guiding plate and a light reflecting member in a single body. A light guiding plate comprises a body(230) and a light reflecting member(250). The body includes a light entering portion(205), a light exiting portion(210), and a rear surface portion(220). The light exiting portion receives the light supplied through the light entering portion, guides the received light, and outputs the guided light. The rear surface portion is disposed to face the light exiting portion, and has a convex shape. The light reflecting member is closely attached onto the rear surface portion.

Description

LIGHT GUIDE UNIT, BACK LIGHT ASSEMBLY HAVING THE LIGHT GUIDE UNIT AND DISPLAY DEVICE HAVING THE SAME}

1 is a perspective view of a light guide unit according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the light guide unit shown in FIG. 1.

3 is a perspective view of a light guide unit according to another embodiment of the present invention.

4 is an exploded perspective view of the light guide unit shown in FIG. 3.

5 is a perspective view of a light guide unit according to another embodiment of the present invention.

FIG. 6 is an exploded perspective view of the light guide unit shown in FIG. 5.

7 is a perspective view of a backlight assembly according to an embodiment of the present invention.

8 is an exploded perspective view of a backlight assembly according to another embodiment of the present invention.

FIG. 9 is a cross-sectional view of the backlight assembly illustrated in FIG. 8 taken along the line II ′.

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

FIG. 11 is a cross-sectional view of the display device illustrated in FIG. 10 taken along the line II-II ′.

<Explanation of symbols for the main parts of the drawings>

100: light guide unit 130: body

150: light reflection member 223: uneven surface 223

322, 324, 326, and 328: first to fourth sub back portions

500: backlight assembly 510: light source

700: display device 730: display panel

The present invention relates to a light guide unit, a backlight assembly having the same, and a display field having the same. More particularly, the present invention relates to a light guide unit for changing and converging a light path, a backlight assembly having the same, and a display field having the same.

In general, the liquid crystal has both electrical and optical characteristics that change the transmittance of light according to the intensity of the electric field. A liquid crystal display device (LCD) displays an image by using the electro-optical characteristics of the liquid crystal (LC).

Since the liquid crystal is a passive element that does not generate light by itself, the liquid crystal display includes a backlight assembly to display an image in a dark place.

Background Art A backlight assembly employed in a conventional display device is classified into a direct downward type back light assembly and an edge type back light assembly according to an arrangement of a light source.

In the direct type backlight assembly, a plurality of light sources are disposed under the display panel. In the edge type backlight assembly, a light source is disposed on a side of the light guide plate to provide light to the display panel.

The edge type backlight assembly includes a plurality of optical sheets to improve light utilization efficiency. The optical sheet includes, for example, a reflection sheet for reflecting and re-incident the light leaking from the light guide plate, and a diffusion sheet and a light collecting sheet for improving the optical characteristics of the light emitted from the light guide plate.

As the backlight assembly includes a plurality of optical sheets, assembly time is required to align the reflective sheet at a designated position, and the volume and weight of the backlight assembly and the display device having the same are increased.

The technical problem of the present invention is to solve such a conventional problem,

One object of the present invention is to provide a light guide unit having a light guide function and a light condensing function.

Another object of the present invention is to provide a backlight assembly including the light guide unit with reduced components.

It is still another object of the present invention to provide a display device including the backlight assembly with reduced components.

In order to realize the above object of the present invention, the light guide unit according to an embodiment of the present invention includes a body and a light reflecting member. The body includes a light incident part, an exit part and a convex back part. The light exits the path guided light with respect to the light provided as the light is provided through the light incident part. The rear portion is disposed to face the exit portion. The light reflecting member is disposed in close contact with the back portion.

Optionally, the back portion includes surfaces having a concave-convex shape for condensing. The concave-convex surfaces progress in the body and condense light incident on the rear portion and exit through the exit portion.

Optionally, said back portion comprises a plurality of convex sub back portions. Optionally, the sub back portions include surfaces having a concave-convex shape for condensing. Preferably, the rear portion includes two or more of the sub rear portions having different extending directions of the uneven surfaces.

In order to realize the above object of the present invention, the backlight assembly according to an embodiment of the present invention includes a light guide unit and a light source. The light guide unit includes a body and a light reflecting member. The body includes an exit portion, a convex back portion and a light incident portion. The rear portion is disposed to face the emitting portion, and the light incident portion connects the rear portion and the emitting portion. The light source provides light to the light incident portion.

Optionally, the back portion includes faces having a concave-convex shape for condensing. Optionally, said backlight assembly further comprises an optical sheet. The optical sheet is disposed on the exit portion and condenses in a direction different from the direction in which the rear portion condenses.

In order to achieve the above object of the present invention, a display device according to an embodiment of the present invention includes a light guide unit, a light source, and a display panel. The display panel displays an image based on the light provided by the light guide unit.

According to the light guide unit, it is possible to provide a light guide unit for changing the path of the light at the same time. In addition, according to the backlight assembly and display device, an optical sheet may be reduced or omitted to provide a backlight assembly and a display device with reduced weight and volume.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Light guide unit

1 is a perspective view of a light guide unit according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the light guide unit shown in FIG. 1.

1 and 2, the light guide unit 100 includes a body 130 and a light reflecting member 150.

The body 130 includes a light incident part 105, an emission part 110, and a rear part 120. The rear part 120 has a convex shape facing the exit part 110. The light incident part 105 connects the emission part 110 and the rear part 120. As the light emitter 110 provides light through the light incident part 105, the light emitter 110 emits light guided by a path with respect to the provided light.

The body 130 is preferably made of a material excellent in light transmittance, heat resistance, chemical resistance and mechanical strength. The body 130 is made of, for example, polymethyl methacrylate (PMMA, PolyMethylMethArylate).

The light reflecting member 150 is disposed in close contact with the back portion 120. Preferably, the light reflecting member 150 is integrally formed with the body 130 on the back portion 120. Accordingly, one surface 151 of the light reflecting member 150 facing the rear part 120 has a concave shape. The light reflection member 150 is preferably made of a metal having excellent light reflection efficiency. The light reflection member 150 includes, for example, silver or aluminum.

The light reflecting member 150 reflects the light incident through the light incident part 105 and leaked to the rear part 120 toward the exit part 110. In this case, since the rear part 120 has a convex shape, the path of the light reflected by the rear part 120 is changed to be closer to the normal direction of the exit part 110.

3 is a perspective view of a light guide unit according to another embodiment of the present invention. 4 is an exploded perspective view of the light guide unit shown in FIG. 3.

3 and 4, the light guide unit 200 includes a body 230 and a light reflecting member 250. Since the light guide unit 200 is the same as the light guide unit 100 illustrated in FIGS. 1 and 2 except that the rear part 220 includes surfaces having an uneven shape, duplicate description thereof will be omitted.

The body 230 includes a light incident part 205, an emission part 210, and a rear part 220. The back portion 220 includes surfaces 223 having a concave-convex shape for condensing. The uneven surfaces 223 extend in one direction from the rear surface portion 220 and are disposed in parallel to each other. Accordingly, the concave-convex surfaces 223 form a condensing pattern 221. 3 and 4, due to the concave-convex surfaces 223, the body 230 includes prism portions forming the rear portion 220.

The light reflection member 250 is disposed to be in close contact with the back portion 220. Preferably, the light reflecting member 250 is formed integrally with the body 230 on the back portion 220. Accordingly, one surface 251 of the light reflecting member 250 facing the rear part 220 may have a concave shape as a whole. In addition, the one surface 251 of the light reflecting member 250 has concave-convex surfaces in close contact with the concave-convex surfaces 223 of the back portion 220.

The light reflecting member 250 is incident through the light incidence part 205 and reflects the light leaking to the back part 220 toward the output part 210. In this case, the back portion 220 has a convex shape as a whole, and the back portion 220 includes surfaces 223 having the concave-convex shape. Accordingly, the path of the light reflected by the rear part 220 is changed to be closer to the normal direction of the exit part 210.

5 is a perspective view of a light guide unit according to another embodiment of the present invention. FIG. 6 is an exploded perspective view of the light guide unit shown in FIG. 5.

5 and 6, the light guide unit 300 includes a body 330 and a light reflecting member 350. The light guide unit 300 includes the light guide unit 200 illustrated in FIGS. 3 and 4 except that the rear part 320 has the first to fourth sub back parts 322, 324, 326, and 328. Duplicate description is omitted since it is the same as.

The body 330 includes a light incident part 305, an emission part 310, and a rear part 320.

The rear part 320 is disposed to face the exit part 310 and has a convex shape. The back part 320 includes first to fourth sub back parts 322, 324, 326, and 328.

In FIG. 6, the rear part 320 has a rectangular shape with respect to the front of the light guide unit 300. The two diagonal lines of the rectangular shape divide the back part 320 into the first to fourth sub back parts 322, 324, 326, and 328. Accordingly, the first to fourth sub back parts 322, 324, 326, and 328 also have convex shapes.

The first sub back part 322 and the third sub back part 326 are arranged symmetrically with respect to the center of the back part 320. The second sub back part 324 and the fourth sub back part 328 are disposed symmetrically with respect to the center of the back part 320.

The first to fourth sub back parts 322, 324, 326, and 328 respectively include surfaces 321, 323, 325, and 327 having concave-convex shapes for condensing. Here, in order to efficiently collect the light traveling in various directions, the uneven surfaces 321, 323, 325, and 327 are arranged in different directions from each other.

For example, the first and third sub back parts 322 and 326 include the uneven surfaces 321 and 325 extending in a first direction, and the second to fourth sub back parts 324. , 328 includes the uneven surfaces 323 and 327 extending in a second direction perpendicular to the first direction.

The light reflecting member 350 is disposed in close contact with the back portion 320. Preferably, the light reflecting member 350 is formed integrally with the body 330 on the back portion 320. Accordingly, the light reflecting member 350 includes reflective surfaces 352, 354, 356, and 358 facing the first to fourth sub back portions 322, 324, 326, and 328 and having a concave shape. .

In addition, the reflective surfaces 352, 354, 356, and 358 of the light reflection member 350 may have the uneven surfaces 321 of the first to fourth sub back parts 322, 324, 326, and 328. , 323, 325, and 327.

Backlight assembly

7 is a perspective view of a backlight assembly according to an embodiment of the present invention.

Referring to FIG. 7, the backlight assembly 500 includes a light guide unit 100 and a light source 510.

Since the light guide unit 100 is the same as the light guide unit 100 shown in FIGS. 1 and 2, the same reference numerals are used, and redundant description thereof will be omitted.

The light source 510 provides light to the light incident part 105 of the light guide unit 100. The light source 510 is disposed to face the light incident part 105. The light source 510 includes a lamp 511 and a lamp reflector 515.

The lamp 511 includes a lamp tube having a straight tube shape and a discharge gas enclosed in the lamp tube. Electrode portions are disposed at both ends of the lamp tube, and a fluorescent layer is disposed on an inner wall of the lamp tube. When a predetermined driving voltage is applied to the electrode portions, the discharge gas emits invisible light by discharge. The fluorescent layer converts the invisible light into visible light.

The lamp reflector 515 reflects the light emitted from the lamp 511 toward the light incident part 105.

In FIG. 7, in order to clearly show the shape of the rear part 120, the thickness of the light reflecting member 150 is exaggerated and shown to be similar to the thickness of the lamp reflector 515. However, the actual thickness of the light reflecting member 150 is much smaller than the thickness of the lamp reflector 515, and the sum of the height of the light incident part 105 and the thickness of the light reflecting member 150 is the lamp. It is similar to the height of the reflector 515.

Light entering the body 130 through the light incidence part 105 is mostly totally reflected by the light emitting part 110 or the light incidence part 105. However, the light propagating inside the body 130 and incident on the rear part 120 is scattered by the light reflecting member 150. As a result, most of the scattered light enters the output unit 110 at an incident angle smaller than the critical angle (incident angle at which total reflection occurs) of the output unit 110, and is emitted through the output unit 110.

At this time, when the rear part 120 faces the rear part 120 in the direction toward the exit part 110, the rear part 120 has a convex shape, but the rear part 120 in the exit part 110. When looking at the back portion 120 in the direction toward), the back portion 120 has a concave shape. Therefore, the light proceeds inside the body 130 and the light incident on the rear part 120 is focused in a direction closer to the normal direction of the exit part 110.

8 is an exploded perspective view of a backlight assembly according to another embodiment of the present invention. FIG. 9 is a cross-sectional view of the backlight assembly illustrated in FIG. 8 taken along the line II ′.

8 and 9, the backlight assembly 600 includes a light guide unit 200 and a light source 610. The light guide unit 200 is the same as the light guide unit 200 shown in FIGS. 3 and 4, and the light source 610 is the same as the light source 510 shown in FIGS. 5 and 6. The description is omitted.

In FIG. 8, the lamp 611 is disposed in a first direction, which is an extension direction of the uneven surfaces 223 formed on the back portion 220. Accordingly, the light guide unit 200 first emits the light provided from the lamp 611 by condensing the light.

Referring to FIG. 9, the light L1 incident on the rear part 220 is due to the concave-convex surfaces 223, and thus the emission part L2 may be larger than the reflected light L2 when the rear part 220 is flat. The light is focused to be closer to the normal direction of 210.

The backlight assembly 600 further includes an optical sheet 650. The optical sheet 650 is disposed on the emission unit 210. The optical sheet 650 is emitted by improving the optical characteristics of the light emitted from the light guide unit 200.

The optical sheet 650 includes a diffusion sheet 630 and a light collecting sheet 640. The diffusion sheet 630 is disposed on the emission unit 210 to improve luminance uniformity of the light emitted from the light guide unit 200.

The light collecting sheet 640 is disposed on the diffusion sheet 630. The light collecting sheet 640 includes prism portions 641 extending in a second direction perpendicular to the first direction. Accordingly, the light collecting sheet 640 secondly collects the light emitted from the diffusion sheet 630. Since the first direction and the second direction are perpendicular to each other, it is obvious that the first condensing direction and the second condensing direction are substantially perpendicular.

Display device

10 is an exploded perspective view of a display device according to an exemplary embodiment. FIG. 11 is a cross-sectional view of the display device illustrated in FIG. 10 taken along the line II-II ′.

10 and 11, the display device 700 includes a light guide unit 200, a light source 610, and a display panel 730. Since the light guide unit 200 and the light source 610 are the same as the light guide unit 200 and the light source 610 illustrated in FIGS. 8 and 9, the same reference numerals are used, and a redundant description thereof will be omitted. The display device 700 further includes an optical sheet 650, and the optical sheet 650 is the same as the optical sheet 650 shown in FIGS. Description is omitted.

The display device 700 further includes a first accommodating member 750 and a second accommodating member 770.

The first accommodating member 750 accommodates the light guide unit 200, the light source 610, and the optical sheet 650. To this end, the first receiving member 750 includes a bottom plate 751 and a first side wall 755.

The light guide unit 200 is disposed on the bottom plate 751. Openings are formed in the bottom plate 751 to reduce the weight of the display device 700. The first sidewall 755 is disposed at the periphery of the bottom plate 751. The light source 610 is accommodated between the light incident part 205 of the light guide unit 200 and the first sidewall 755.

The second accommodating member 770 prevents the light guide unit 200, the light source 610, and the optical sheet 650 from being separated from the first accommodating member 750. The second accommodating member 770 includes a support plate 771 and a second sidewall 775.

The support plate 771 is disposed to face the bottom plate 751. The support plate 771 presses an edge of the optical sheet 650 to support the display panel 730, which will be described later. The second sidewall 775 extends from the edge of the support plate 771 to cover the first sidewall 755.

The display panel 730 displays an image based on the light provided by the light guide unit 200. The display panel 730 is disposed on the stepped portion formed on the support plate 771. The display panel 730 includes a first substrate 710, a second substrate 720, and a liquid crystal layer (not shown).

The first substrate 710 is a transparent glass substrate in which a thin film transistor, which is a switching element, is formed in a matrix form. The pixel electrode made of a transparent conductive material is formed on the first substrate 710.

The second substrate 720 is disposed to face the first substrate 710 at a predetermined interval. The second substrate 720 is a substrate in which RGB pixels, which are color pixels that are expressed in a predetermined color when light passes, are formed by a thin film process. A common electrode made of a transparent conductive material is formed on the entire surface of the second substrate 720 facing the first substrate 710 to correspond to the pixel electrode formed on the first substrate 710.

The display panel 730 further includes a printed circuit board 715 and a connection film 718. The printed circuit board 715 generates a driving signal for driving the display panel 730. The printed circuit board 715 is electrically connected to one edge of the first substrate 710 through the connection film 718. The printed circuit board 715 is disposed on the bottom surface of the bottom plate 751 as the connection film 718 is bent to surround the second sidewall 775.

When an electric field is formed between the first substrate 710 and the second substrate 720 according to the driving signal applied from the printed circuit board 715, the first substrate 710 and the second substrate The arrangement of the liquid crystal layer interposed between 720 is changed. As a result, the transmittance of light provided from the optical sheet 650 is changed, and the display apparatus 700 displays an image having a desired gray scale.

10 and 11, the light reflecting member 250 includes a metal such as silver or aluminum, for example. Therefore, the light reflection member 250 blocks the electromagnetic waves generated from the printed circuit board 715 from being emitted to the front face of the display device 700. In addition, the light reflection member 250 prevents the electromagnetic waves generated from the display panel 730 from being emitted to the rear face of the display device 700.

10 and 11, the display device 700 guides the display panel 730 and is coupled to the second accommodating member 770 or the first accommodating member 750. More). The third accommodating member 790 covers an edge of the display panel 730 to expose the effective display area of the display panel 730.

As described in detail above, according to the present invention, the light guide unit includes a light reflecting member formed integrally with the body. Therefore, the components of the backlight assembly and the display device are reduced, thereby improving the assemblability of the backlight assembly and the display device.

In addition, the body includes a convex back portion, and a light reflecting member is disposed in close contact with the back portion. Therefore, the light guide unit changes and condenses the path of the incident light and emits the light. Thus, the front luminance of the display device is improved. In addition, the light collecting sheet may be reduced or omitted in the backlight assembly and the display device. As a result, the volume and weight of the backlight assembly and the display device are reduced.

In addition, the light reflection member blocks electromagnetic waves. Therefore, in the backlight assembly and the display device, the cover member made of a metal material for blocking the propagation of electromagnetic waves generated in the printed circuit board or the display panel may be omitted.

In the detailed description of the present invention described above with reference to the preferred embodiments of the present invention, those skilled in the art or those skilled in the art having ordinary skill in the art will be described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the scope of the present invention.

Claims (8)

A body including a light incident part, an emission part for emitting a light guided by a path with respect to the provided light, as the light is provided through the light incident part, and a rear part convex while facing the emission part; And And a light reflecting member disposed to be in close contact with the back portion. The light guide unit according to claim 1, wherein the rear portion includes surfaces having concave-convex shapes for condensing. The light guide unit of claim 1, wherein the back portion comprises a plurality of convex sub back portions. The method of claim 3, wherein the sub back portion includes a surface having a concave-convex shape for condensing, And the back portion comprises at least two sub back portions having different extending directions of the uneven surfaces. A light guide unit including an emission unit, a body having a convex rear surface facing the emission unit, a light incident unit connecting the emission unit and the rear surface, and a light reflection member disposed in close contact with the rear surface; And And a light source for providing light to the light incident portion. The backlight assembly of claim 5, wherein the rear portion comprises surfaces having concave-convex shapes for condensing. The backlight assembly of claim 6, further comprising an optical sheet disposed on the emission unit and configured to collect the light in a direction different from a light condensing direction in which the rear surface is condensed. A light guide unit including a light emitting part, a body having a convex back surface facing the light emitting part and a light incident part connecting the light emitting part and the back part, and a light reflecting member disposed in close contact with the back part; A light source providing light to the light incident part; And And a display panel configured to display an image based on the light provided by the light guide unit.

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