KR101296467B1 - back light unit and display device having it - Google Patents

Abstract

The present invention proposes a backlight unit capable of selectively using internal light and external light and a display device having the same.

The present invention provides a backlight unit having a light emitting area and a non-light emitting area around the light emitting area, the light guide plate disposed in the light emitting area; At least one lamp forming one surface with the light guide plate and disposed in the non-light emitting area; And a bottom case accommodating the light guide plate and the lamp and having an opening at a bottom thereof corresponding to the light emitting area.

The display device according to the present invention displays an image on the display panel using the external light as a backlight when the external light is sufficient, and displays an image on the display panel by driving the backlight unit when the external light is insufficient. Provided is a display device having a backlight unit that can flexibly cope with and reduce backlight power consumption.

Backlight unit, display device, light reflecting member, opening

Description

Back light unit and display device having it

1 is an exploded perspective view illustrating a display device according to a first exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view of the display device taken along the line II ′ of FIG. 1. FIG.

3a and 3b are perspective views showing the characteristics of the light reflection transmitting member according to the present invention.

4A is an exploded perspective view illustrating a display device using internal light in the present invention.

4B is a cross-sectional view taken along line II-II 'of FIG. 4A.

5A is an exploded perspective view illustrating a display device using internal light in the present invention.

FIG. 5B is a cross-sectional view taken along line III-III ′ of FIG. 5A;

6 is a cross-sectional view of a display device according to a second exemplary embodiment of the present invention.

7 is a cross-sectional view of a display device as a third embodiment according to the present invention.

8 is a cross-sectional view of a display device as a fourth embodiment according to the present invention;

Description of the Related Art [0002]

100, 200, 300, 400: display device 110, 210, 310, 410: display panel

120, 220, 320, 420: backlight unit 165, 265, 365, 465: first light

166, 266, 366, 466: Second light 170, 270, 370, 470: Light reflecting member

180, 280, 380, 480: Bottom case 181, 281, 381, 481: Opening

248: sensor 372, 472: diffusion sheet

376: light efficiency enhancing film 474: prism sheet

The present invention proposes a backlight unit capable of selectively using internal light and external light and a display device having the same.

With the development of the information society, in recent years, there have been various liquid crystal display devices (LCDs), plasma display panels (PDPs), electroluminescent displays (VFDs), and vacuum fluorescent displays (VFDs). Flat panel display devices have been studied.

Among these display devices, a liquid crystal display device is a flat panel display device that displays an image using liquid crystal, and is thinner and lighter than other display devices, and has low power consumption and low driving voltage. Its advantages are widely used throughout the industry.

The liquid crystal display has a structure in which a liquid crystal is interposed between two substrates. In this case, the liquid crystal is controlled by the voltage applied between the two substrates to display a predetermined image. Since the LCD does not emit light by itself, a backlight unit for irradiating light from the outside is required. However, the backlight unit for providing light to the liquid crystal display device is a high power consumption device.

In recent years, as the demand for large display devices of consumers increases, studies on the substrate size and the size of the backlight unit have been actively conducted.

In order to increase the size of the backlight unit, it is necessary to overcome technical limitations in manufacturing the backlight unit such as increasing the size of the lamp, delaying the lighting time of the lamp, and increasing the power consumption.

As such, the burden on research and development costs and investment costs for a large backlight unit is increasing, but there is a problem that it is difficult to overcome the technical limitations of the backlight unit manufacturing.

The present invention has a first object to provide a backlight unit capable of providing an external light incident through the opening to a display panel by forming an opening corresponding to an active area of the display panel in a bottom case accommodating the backlight unit. .

The display device according to the present invention displays an image on the display panel using the external light as a backlight when the external light is sufficient, and displays an image on the display panel by driving the backlight unit when the external light is not sufficient. It is a second object to provide a display device having a backlight unit that can flexibly cope with the problem and can reduce the power consumption of the backlight.

According to an aspect of the present invention, there is provided a light emitting device including: a light guide plate disposed in the light emitting area in a backlight unit having a light emitting area and a non-light emitting area around the light emitting area; At least one lamp forming one surface with the light guide plate and disposed in the non-light emitting area; And a bottom case accommodating the light guide plate and the lamp and having an opening at a bottom thereof corresponding to the light emitting area.

According to an aspect of the present invention, a display device includes: a display panel; And a backlight unit having a light emitting area for providing light to the display panel and a non-light emitting area around the light emitting area, wherein the backlight unit comprises: a light guide plate disposed corresponding to the light emitting area; At least one lamp forming one surface with the light guide plate and disposed in the non-light emitting area; And a bottom case accommodating the light guide plate and the lamp and having an opening at a bottom thereof to receive external light corresponding to the light emitting area.

According to the present invention, when the external light is sufficient to display the image on the display panel using the external light as a backlight, if the external light is not enough to drive the backlight unit to display the image on the display panel to be flexible to the surrounding environment It is possible to reduce the backlight power consumption.

Hereinafter, a backlight unit and a display device according to the present invention will be described in detail with reference to the accompanying drawings.

1 is an exploded perspective view illustrating a display device according to a first exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view of the display device taken along the line II ′ of FIG. 1.

1 and 2, the display device 100 according to the present invention includes a display panel 110 for displaying an image and a backlight for providing light of an internal light source or an external light source to the display panel 110. Unit 120.

The backlight unit 120 includes a lamp 160 and a light guide plate 150 to provide light of an internal light source to the display panel 110.

In the backlight unit 120, a predetermined opening 181 is formed in the backlight unit 120 disposed between the display panel 110 and the external light source to transmit light of an external light source to the display panel 110. do.

Preferably, the backlight unit 120 is made of an opaque metal material, and preferably does not include a reflector that reflects all incident light.

The display panel 110 is an element that displays an image by using light, for example, a liquid crystal panel.

The display panel 110 has an active area that substantially displays an image and a non-active area around the active area.

The display device 100 further includes a top case 111 provided to surround the inactive region of the display panel 110 and coupled to the backlight unit 120.

The display panel 110 may include, for example, a first substrate 115 on which a thin film transistor array is bonded and a second substrate 116 on which a color filter pattern is formed so that the liquid crystal panel is opposed to each other to maintain a uniform cell gap. And a liquid crystal layer interposed between the first substrate 115 and the second substrate 116.

In detail, the display panel 150 according to the present invention includes a plurality of unit pixels in the active area.

The unit pixels P include a red pixel R, a green pixel G, and a blue pixel B.

The first substrate 115 is formed by crossing a plurality of gate lines and a plurality of data lines.

An area formed by crossing the gate line and the data line forms the unit pixel.

The unit pixel includes at least one thin film transistor (TFT) and a pixel electrode connected to the thin film transistor (TFT).

The thin film transistor may include a gate electrode electrically connected to the gate wiring, a semiconductor pattern formed on the gate electrode, a gate insulating layer interposed between the semiconductor pattern and the gate electrode, and contacting one side of the semiconductor pattern and connected to the data wiring. A source electrode and a drain electrode contacting the other side of the semiconductor pattern and spaced apart from the source electrode.

A passivation layer may be formed on the entire surface of the first substrate 115 to cover the thin film transistor TFT. In this case, the passivation layer may further include a contact hole exposing a part of the drain electrode.

The unit pixel further includes a pixel electrode electrically connected to the thin film transistor TFT.

The pixel electrode is made of a transparent conductive electrode material.

The transparent conductive electrode material includes at least one selected from the group consisting of indium tin oxide (ITO) and indium zinc oxide (IZO).

The second substrate 116 facing the first substrate 115 has red, green, and blue color filter patterns corresponding to the red, green, and blue pixels, respectively.

The second substrate 116 may further include a light blocking pattern in a region corresponding to the gate wiring, the data wiring, and the thin film transistor TFT.

The gate wiring, the data wiring, the thin film transistor, and the like may not substantially transmit light, and may cause light leakage around them, thereby degrading image quality. Therefore, the light blocking pattern serves to block light leakage.

The light blocking pattern may be formed of at least one of a metal, a metal oxide, and an organic material.

A common electrode may be further formed on the entire surface of the second substrate 116.

An electric field is generated between the pixel electrode on the first substrate 115 and the common electrode on the second substrate 116.

A sealant is formed around the inactive region of the outer side of the first substrate 115 and the second substrate 116, and both substrates are bonded by the encapsulant.

The liquid crystal layer is interposed between the first substrate 115 and the second substrate 116.

In addition, a first polarizing film may be disposed on an outer surface of the first substrate 115, and a second polarizing film may be disposed on an outer surface of the second substrate 120.

The first polarization direction of the first polarizing film and the second polarization direction of the second polarizing film may coincide with each other. In addition, the first polarization direction and the second polarization direction may be perpendicular to each other. In addition, the first polarization direction and the second polarization direction may have different directions.

The arrangement of the liquid crystal molecules of the liquid crystal layer is changed by an electric field generated between the pixel electrode and the common electrode. According to the arrangement of the liquid crystal molecules, the transmittance of polarized light incident and passing through the display panel 110 is changed.

The backlight unit 120 may include a lamp 160 disposed at one side to emit light, a light guide plate 150 arranged to form one surface with the lamp 160, and converting the linear light incident from the lamp into surface light; A lamp housing 161 provided to surround the lamp 160 to inject light emitted from the lamp 160 into the light guide plate 150, and an optical lens disposed on the light guide plate 150 to diffuse and collect light. Sheets 130 are included.

The backlight unit 120 has a frame-shaped support main 140 in which the lamp 160, the lamp housing 161, the light guide plate 150, and the optical sheets 130 are accommodated, and a box shape having an upper surface open. The bottom case (bottom case, 180) further comprises.

The bottom case 180 has a predetermined opening 181 on the bottom surface.

The opening 181 corresponds to the active area of the display panel 110.

The opening 181 may have the same size as the active area. Alternatively, the size of the opening 181 may be larger than the active area.

The opening 181 receives external light generated outside the display device 100 so that the external light can be provided to the display panel 110.

The external light passes through the light guide plate 150 and the optical sheets 130 and then enters the display panel 110.

The external light may be a natural light source, for example, light provided from the sun, an artificial light source, for example, light provided from a lamp or the like.

The support main 140 and the bottom case 180 may be fastened by a screw or hook structure.

The light emitted from the lamp 160 may be divided into light incident directly on the incident surface of the light guide plate 150 and light incident on the incident surface of the light guide plate 150 by being reflected by the lamp housing 161.

The lamp 160 is disposed to form one surface on one side of the light guide plate 150, and the lamp 160 may be further disposed while forming one surface on the other side of the light guide plate 150.

The lamp 160 may be at least one of a Cold Cathode Fluorescence Lamp (CCFL), an External Electrode Fluorescent Lamp (EEFL), and a light emitting diode (LED).

The lamp 160 has a side of the light guide plate 150 such that 'a', 'c', 'ㅁ' and '| | ' It may be arranged in any one of the shape.

The light guide plate 150 guides the light incident from the lamp 160 to convert the light guide plate into a surface light source and direct the light to the panel.

The light guide plate 150 may be made of poly methyl metharylate acrylate (PMMA).

The light guide plate 150 may have a wedge shape in which the thickness becomes thinner as it moves away from the incident surface on which the lamp 160 is disposed. In addition, the light guide plate 150 may have a uniform thickness.

A pattern for refracting incident light in the direction of the optical sheets 130 may be formed on the rear surface of the light guide plate 150.

In the embodiment according to the present invention, the light reflection transmitting member 170 may be disposed between the bottom case 180 and the light guide plate 150.

The light reflection transmitting member 170 includes at least one of a light efficiency enhancing film, a diffusion sheet, and a prism sheet.

A transparent protective plate may be further disposed between the light reflection transmitting member and the bottom case. The transparent protective plate may protect the light reflective member from foreign matter, and serves to support the light reflective member.

The transparent protective plate may be a plastic substrate or a glass substrate.

The light efficiency enhancing film may be at least one of a dual brightness enhancement film (DBEF) and a brightness enhancement film (BEF).

The light efficiency improving film transmits a part of light incident in the light propagation direction as it is, and reflects another part.

The diffusion sheet may include, for example, at least one of acrylic, polycarbonate, and polyester.

The diffusion sheet not only serves to diffuse the incident light to have a uniform distribution, but may also reflect a portion of the light incident on the surface of the diffusion sheet.

The prism sheet serves to adjust the traveling direction of the light, for example, may have a prism acid on one surface of the prism sheet.

For example, the light efficiency improving film may be disposed between the light guide plate 150 and the bottom case 180 of the light reflection transmitting member 170. In this case, the optical efficiency enhancing film selectively reflects internal light incident from the lamp 160 to the display panel 110, and external light entering through the opening 181 is selectively displayed on the display panel 110. Permeate through. A diffusion sheet may be further disposed on the light efficiency enhancing film.

As another example, the diffusion sheet and the prism sheet may be disposed between the light guide plate 150 and the bottom case 180. In this case, a prism sheet may be disposed below the light guide plate 150, and a diffusion sheet may be disposed between the prism sheet and the bottom case 180. The diffusion sheet and the prism sheet selectively reflect internal light incident from the lamp 160 to the display panel 110. The surface of the diffusion sheet may reflect the incident internal light. The prism sheet may improve the brightness by collecting the direction of the internal light reflected randomly. The diffusion sheet and the prism sheet transmit external light that enters through the opening 181 of the bottom case 180 to the display panel 110.

Meanwhile, a diffusion sheet may be disposed below the light guide plate 150, and a prism sheet may be disposed between the diffusion sheet and the bottom case 180.

The intensity of the internal light generated from the lamp 160 is lower than that of the bottom case 180.

When the cell is larger than the intensity of the external light incident through the opening 181, the internal light is reflected by the light reflecting member 170 and is incident on the display panel 110. For example, since the display panel uses the lamp as a main light source at night, the internal light intensity is greater than the external light intensity.

When the intensity of the external light incident to the opening 181 of the bottom case 180 is greater than the intensity of the internal light generated from the lamp 160, the external light passes through the light reflecting member 170. The light enters the display panel 110. For example, since the display panel uses external light as a main light source during the day, the intensity of the external light is greater than that of the internal light.

The display device 100 having the above structure can be driven in various ways.

For example, the display device 100 turns off the lamp when sufficient external light is provided. In addition, external light incident through the opening 181 of the bottom case 180 is used as a backlight. The external light is incident on the light reflecting member 170, the light guide plate 150, the optical sheets 130, and the display panel 110 to display an image.

In this case, the display device 100 may be disposed such that a rear surface of the display device 100 faces the external light source so that external light may be incident through the opening 181 of the bottom case 180. . For example, the display device 100 may be attached to a window of a building.

For example, the display device 100 turns on the lamp 160 when there is insufficient external light. In addition, the internal light generated by the lamp 160 is used as a backlight. The internal light is incident on the light guide plate 150 from the lamp 160. The incident internal light becomes surface light from the light guide plate 150 to be incident on the display panel 110, and the internal light irradiated to the rear surface of the light guide plate 150 is reflected by the light reflecting member 170 and is again reflected by the light guide plate. And incident to the display panel 110.

The display device 100 having the above structure is only an embodiment of the display device according to the present invention, and the display panel 110 of the present invention can be applied to any structure capable of displaying an image using incident light. .

For example, the display device 100 of the present invention may be applied to a liquid crystal display device in an in-plane switching mode (IPS mode) in which a pixel electrode and a common electrode are formed on one substrate.

In addition, the display device 100 of the present invention may be applied to a transmissive display device that displays an image by transmitting only light of the backlight unit to the display panel. The display device 100 of the present invention may be applied to a reflection type display device in which internal light generated by the backlight unit is incident on a display panel and reflects external light incident on the front surface of the display panel to display an image.

The gate driving circuit unit may be connected to the gate lines to apply a gate signal to the gate lines, and the data driving circuit unit may be connected to the data lines to apply a data signal to the data lines. Can be deployed.

The gate driving circuit unit and the data driving circuit unit may be formed on the inactive region NA of the first substrate 110.

Preferably, the printed circuit board as well as the gate driving circuit unit and the data driving circuit unit are disposed so as not to cover the opening 181 of the bottom case 180.

The display device 100 according to the present invention can implement a lightweight and thin display device, and can selectively drive the backlight unit 120 according to a situation without always driving the backlight unit 120, thereby consuming power of the display device 100. Can save considerable.

3A and 3B are perspective views showing the characteristics of the light reflection transmitting member according to the present invention.

Referring to FIG. 3A, the light reflection transmitting member 170 according to the present invention emits the first light 165 incident to the first surface in the first direction to the second surface.

For example, when the light reflection transmitting member 170 has a laminated structure of a diffusion sheet and an optical efficiency enhancing film, the first surface becomes one surface of the diffusion sheet and the second surface becomes one surface of the optical efficiency enhancing film. . In contrast, the first surface is one surface of the light efficiency enhancing film and the second surface is one surface of the diffusion sheet.

While the first light 165 passes through the light reflective member 170, some light may be reflected or absorbed by the light reflective member 170, but even if some light is lost, the light reflective member ( The first light 166 transmitted through the 170 may sufficiently display an image.

Referring to FIG. 3B, the light reflecting member 170 according to the present invention reflects the second light 166 incident on the second surface in a second direction opposite to the first direction.

For example, when the light reflection transmitting member 170 has a laminated structure of a diffusion sheet and a light efficiency enhancing film, part of light incident from a lamp is reflected by the light efficiency enhancing film and other light is transmitted. The transmitted light is partially reflected by the diffusion sheet and is incident to the light efficiency improving film. Some of the incident light is transmitted and some other light is reflected. The above process is repeated, and most of the second light 166 incident to the light reflective member 170 is reflected by the light reflective member 170 to be incident on the light guide plate 150.

While the second light 166 is reflected from the light reflecting member 170, some light may pass through the light reflecting member 170 as it is, but some light may be left as it is. Even if it passes through, the image may be sufficiently displayed by using the second light 166 reflected by the light reflection transmitting member 170.

4A is an exploded perspective view illustrating a display device using internal light in the present invention, and FIG. 4B is a cross-sectional view taken along line II-II ′ of FIG. 4A.

As shown in FIGS. 4A and 4B, the first light 165 incident from the outside through the opening 181 of the bottom case 180 of the display device 100 may be formed of the light reflecting member 170 and the first light 165. The light guide plate 150 passes through the optical sheet 130 and is incident to the display panel 110.

The first light 165 incident to the display panel 110 passes through the display panel 150 and the transmittance is changed to display an image on the screen.

5A is an exploded perspective view illustrating a display device using internal light in the present invention, and FIG. 5B is a cross-sectional view taken along line III-III ′ of FIG. 5A.

As shown in FIGS. 5A and 5B, the second light 166 generated from the lamp 160 is reflected by the light reflecting member 170 so that the light guide plate 150 and the optical sheet 130 are formed. After passing through the light, the light is incident on the display panel 110.

The second light 166 incident on the display panel 110 transmits the second light 166 while passing through the display panel 110 to display an image in the active area of the display panel.

6 is a cross-sectional view of a display device according to a second exemplary embodiment of the present invention.

Detailed description of the same parts as those described above with reference to FIGS. 1 and 2 will be omitted.

As illustrated in FIG. 6, the display device 200 includes a bottom case 280 having an opening 281.

The display device 200 may further include at least one sensor 248 for measuring the amount of external light generated from an external light source and incident on the opening 281 of the display panel 210.

The sensor 248 measures the amount of light of external light (hereinafter referred to as 'first light').

The first light 265 may be natural light or artificial light.

The natural light may be, for example, sunlight.

The artificial light may be, for example, illumination light.

For example, the first light 265, the amount of light varies depending on the time of day, dawn, morning, afternoon, evening, night. In addition, the sun may be obscured by clouds or the amount of light may change from time to time depending on the state of the atmosphere. In addition, the sun has a different amount of light even in the same time zone depending on the season. In addition, the sun has a different amount of light even in the same time zone depending on the region. In addition, according to the surrounding conditions of the place where the display device is installed, for example, a building, the amount of light incident on the display device may vary.

The sensor 248 measures the amount of light of the first light 265 that changes with time as described above.

The display device may further include a sensor configured to measure internal light (hereinafter, referred to as “second light”) generated from the lamp of the backlight unit.

The sensor 248 may be attached to one side of the display panel 210.

The sensor 248 may be included in the backlight unit.

The sensor 248 may be disposed on a portion of an outer surface of the bottom case 280.

The sensor 248 may be formed in a space provided in the bottom case 280.

Optionally, the sensor 248 and the backlight unit may be connected to each other by a connection part.

The sensor 248 may control the lamp 260 by measuring the amount of light of the first light 265.

For example, when the light amount of the first light 265 is reduced, the sensor 248 may detect this and increase the light amount of the second light 266 of the lamp 260. Accordingly, the sum of the amounts of light of the first light 265 and the second light 266 incident on the display panel 210 may be kept constant.

The connection part may be an electrical wiring. In addition, the connection unit may be a control unit. The controller may be a switching member, a signal conversion member, or the like.

The connection part electrically connects the sensor 248 and the lamp 260, and the connection part inputs information on the amount of light incident from the sensor 248 into the opening 281 of the bottom case 280. It may also serve to adjust the intensity of the light of the lamp 260 compared to the reference.

The sensor 248 may be powered off or on by the user.

The first light 265 entering the opening 281 of the bottom case 280 passes through the light reflecting member 270, the light guide plate 250, and the optical sheets 230, and enters the display panel 210. do.

A portion of the second light 266 generated from the lamp 260 is incident to the display panel 210 via the light guide plate 250 as a surface light source, and another portion of the second light 266 is applied to the display panel 210. Reflected by the light reflection transmitting member 270 is incident to the display panel 210.

The first light 265 and the second light 266 incident on the display panel 210 are transmitted through the display panel 210 and the transmittance is changed to display an image on the screen.

7 is a cross-sectional view of a display device as a third embodiment according to the present invention.

Here, the detailed description of the same parts as those described above with reference to FIGS. 1 and 2 will be omitted.

 As shown in FIG. 7, the display device 300 according to the present invention includes a display panel 310 for displaying an image and a backlight unit for providing light to the display panel 310.

The backlight unit includes a frame main support 340 in which the lamp 360, the lamp housing 361, the light guide plate 350, and the optical sheets 330 are accommodated, and a bottom case having a box shape with an upper surface open. 380 is further included.

The bottom case 380 has a predetermined opening 381 in the bottom surface thereof.

The opening 381 corresponds to the active area of the display panel 310.

A light reflection transmitting member 370 is further formed between the bottom case 380 and the light guide plate 250.

The light reflection transmitting member 370 includes a diffusion sheet 372 and a light efficiency improving film 376.

The diffusion sheet 372 is made of acrylic material, and the diffusion sheet 372 reflects a part of light at the surface and transmits the other part.

The light efficiency enhancing film 376 may be at least one of a dual brightness enhancement film (DBEF) and a brightness enhancement film (BEF).

The light efficiency improving film 376 transmits a part of light incident in the light propagation direction as it is, and reflects another part.

Here, the vibration direction of the light reflected by the light efficiency enhancing film and the polarization axis of the lower polarizer disposed below the display panel are preferably coincident with each other.

The first light 365 introduced through the opening 381 of the bottom case 380 passes through the diffusion sheet 372 and the light efficiency enhancing film 376 and then the light guide plate 350 and the optical sheet 330. And enters the display panel 310.

The second light 366 generated by the lamp 360 is reflected by the diffusion sheet 372 and the light efficiency enhancing film 376 to the light guide plate 350, the optical sheets 330, and the display panel 310. Enter.

Thus, when sufficient external light is provided, the display device 300 may use external light incident through the opening 381 of the bottom case 380 as a backlight.

In addition, when the external light is not sufficient, the display device 300 may use the internal light generated by the lamp 360 as a backlight.

8 is a cross-sectional view of a display device as a fourth embodiment according to the present invention.

Here, the detailed description of the same parts as those described above with reference to FIG. 7 will be omitted.

A light reflection transmitting member 470 is further formed between the bottom case 480 and the light guide plate 450.

The light reflection transmitting member 470 includes a diffusion sheet 472 and a prism sheet 474.

The diffusion sheet 472 is made of an acrylic material, and the diffusion sheet 472 reflects a part of light from the surface and transmits another part thereof.

The prism sheet 474 serves to adjust a traveling direction of light, and for example, may have a prism acid on one surface of the prism sheet 474.

A prism sheet 474 is disposed below the light guide plate 350, and a diffusion sheet 472 is disposed between the prism sheet 474 and the bottom case 480.

The diffusion sheet 472 and the prism sheet 474 selectively reflect the second light 466 incident from the lamp 460 to the display panel 410, and open the opening of the bottom case 480. The first light 465 incident through the 481 passes through the display panel 410.

The surface of the diffusion sheet 472 may reflect a portion of the second light 466 that is incident.

The prism sheet 474 may improve luminance by collecting the direction of the second light 466 that is randomly reflected to the front.

The diffusion sheet 472 may be disposed below the light guide plate 450, and a prism sheet 474 may be disposed between the diffusion sheet 472 and the bottom case 480.

When the external light is sufficient, the display device 410 may use external light incident through the opening 481 of the bottom case 480 as a backlight.

The external light is incident on the diffusion sheet 472 and the prism sheet 474, the light guide plate 450, the optical sheets 430, and the display panel 410 to display an image.

In addition, the display device may use the internal light generated by the lamp as a backlight when the external light is insufficient.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

The display device according to the present invention displays an image on the display panel using the external light as a backlight when the external light is sufficient, and displays an image on the display panel by driving the backlight unit when the external light is insufficient. It can cope flexibly and reduce the power consumption of the backlight.

Claims (14)

In the backlight unit having a light emitting area and a non-light emitting area around the light emitting area, A light guide plate disposed in the light emitting area; At least one lamp forming one surface with the light guide plate and disposed in the non-light emitting area; A lamp housing surrounding the lamp and reflecting light generated from the lamp; A bottom case accommodating the light guide plate and the lamp and having an opening at a bottom thereof corresponding to the light emitting area; And A light reflecting member disposed between the light guide plate and the bottom case and reflecting a part of the light incident from the lamp and transmitting a part of the light incident through the opening; The light reflection transmitting member, An upper surface is in contact with the rear surface of the light guide plate, The end of the rear surface is in contact with the end of the inner surface of the lamp housing, The edge unit is in contact with one end of the bottom case, the backlight unit, characterized in that. The method of claim 1, The backlight unit further comprises an optical sheet disposed on the light guide plate. delete The method of claim 1, The light reflecting member includes at least one of a light efficiency enhancing film, a diffusion sheet, and a prism sheet. delete Display panel; And A backlight unit having a light emitting area for providing light to the display panel and a non-light emitting area around the light emitting area; The backlight unit includes: A light guide plate disposed corresponding to the light emitting area; At least one lamp forming one surface with the light guide plate and disposed in the non-light emitting area; A lamp housing surrounding the lamp and reflecting light generated from the lamp; A bottom case accommodating the light guide plate and the lamp and having an opening at a bottom thereof to receive external light corresponding to the light emitting area; And A light reflecting member disposed between the light guide plate and the bottom case and reflecting a part of the light incident from the lamp and transmitting a part of the light incident through the opening; The light reflection transmitting member, An upper surface is in contact with the rear surface of the light guide plate, The end of the rear surface is in contact with the end of the inner surface of the lamp housing, An edge area is in contact with one end of the bottom case. The method according to claim 6, And an optical sheet disposed on a rear surface of the display panel corresponding to the emission area. The method according to claim 6, In the display panel, A first substrate; A display element formed on the first substrate; A second substrate bonded to the first substrate; A liquid crystal layer interposed between the first substrate and the second substrate; A first polarizing film disposed on one surface of the first substrate; And And a second polarizing film disposed on one surface of the second substrate. The method according to claim 6, The display device may include a thin film transistor and a pixel electrode connected to the thin film transistor. The method according to claim 6, And the second substrate further comprises a color filter pattern. The method according to claim 6, And a top case surrounding the edge of the display panel and fastened to the bottom case. delete The method according to claim 6, The light reflecting member includes at least one of an optical efficiency enhancing film, a diffusion sheet, and a prism sheet. delete

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