KR20070049293A - Back light assembly and liquid crystal display apparatus having the same - Google Patents

Abstract

Disclosed are a backlight assembly and a liquid crystal display having the same, which can improve light utilization efficiency. The backlight assembly includes first and second lamps and a reflective member. The first lamp generates first visible light. The second lamp generates infrared light. The reflecting member reflects the first visible light and has a semiconductor fluorescent layer that generates the second visible light in response to the infrared light. The second lamp is disposed between the first lamps. Therefore, the light utilization efficiency can be improved and the brightness can be increased.

Description

BACK LIGHT ASSEMBLY AND LIQUID CRYSTAL DISPLAY APPARATUS HAVING THE SAME}

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

FIG. 2 is a combined cross-sectional view of the backlight assembly shown in FIG. 1.

FIG. 3 is a cross-sectional view illustrating a path in which visible light is reflected in the semiconductor fluorescent layer illustrated in FIG. 1.

4 is a cross-sectional view illustrating a path in which visible light is generated by infrared light in the semiconductor fluorescent layer shown in FIG. 1.

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

FIG. 6 is a combined cross-sectional view of the backlight assembly shown in FIG. 5.

7 is a combined cross-sectional view of a backlight assembly according to another embodiment of the present invention.

8 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

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

100: first lamp 110, 120, 220: visible light

200: second lamp 210: infrared light

300: reflection member 310: base substrate

320: semiconductor fluorescent layer 330: electron

400: diffuser 500: optical sheet

600: storage container 700: backlight assembly

800: display unit 810: liquid crystal display panel

820: driving circuit portion 900: top chassis

1000: liquid crystal display

The present invention relates to a backlight assembly and a liquid crystal display device having the same, and more particularly, to a backlight assembly and a liquid crystal display device having the same that can improve the light utilization efficiency.

In general, the liquid crystal display is a flat panel display that displays an image by using the electrical and optical characteristics of the liquid crystal (Liquid Crystal) having the intermediate characteristics of liquid and solid, and is thinner, lighter, and lower than other display devices. There is an advantage of having a driving voltage and low power consumption, which is widely used throughout the industry.

Such a liquid crystal display device requires a backlight assembly for supplying additional light because the liquid crystal display panel for displaying an image is a non-light emitting device that does not emit light by itself.

In the conventional backlight assembly, an elongated cylindrical cold cathode fluorescent lamp (CCFL) is mainly used as a light source. The cold cathode fluorescent lamp includes a lamp body made of glass, an internal electrode disposed inside the lamp body to apply a discharge voltage, and a fluorescent film formed on an inner wall of the lamp body. The discharge gas for emitting light is injected into the inner space of the lamp body. The fluorescent film is excited by the ultraviolet rays generated by the discharge gas through the plasma discharge to emit visible light.

Recently, as a liquid crystal display device is enlarged, a backlight assembly having high brightness and providing uniform light over a large area is required. In order to meet this demand, the backlight assembly needs a plurality of lamps. Here, the plurality of lamps are disposed in parallel on the same plane, and a reflecting member for reflecting light emitted from the lower part of the lamps to the liquid crystal display panel is disposed under the lamps.

However, the reflecting member absorbs some of the light emitted from the lamp, causing a problem that the utilization efficiency of the light is lowered.

Accordingly, the present invention has been made in view of such a problem, and an object of the present invention is to provide a backlight assembly capable of improving light utilization efficiency.

Another object of the present invention is to provide a liquid crystal display device having the above-described backlight assembly.

The backlight assembly according to one aspect of the present invention described above includes first and second lamps and a reflective member. The first lamp generates first visible light. The second lamp generates infrared light. The reflective member has a semiconductor fluorescent layer that reflects the first visible light and generates a second visible light in response to the infrared light.

A liquid crystal display according to an aspect of the present invention described above includes a backlight assembly for generating light, a display unit for displaying an image using light from the backlight assembly, and a top chassis for fixing the display unit. The backlight assembly includes first and second lamps and a reflective member. The first lamp generates first visible light. The second lamp generates infrared light. The reflective member has a semiconductor fluorescent layer that reflects the first visible light and generates a second visible light in response to the infrared light. The display unit includes a liquid crystal display panel for displaying an image and a driving circuit unit for driving the liquid crystal display panel.

According to such a backlight assembly and a liquid crystal display having the same, the reflection member emits light absorbed by the semiconductor fluorescent layer formed on the upper surface of the visible light incident from the lamps by the infrared light to the visible light, thereby utilizing the light. The efficiency can be improved.

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

1 is an exploded perspective view of a backlight assembly according to an exemplary embodiment of the present invention, and FIG. 2 is a combined cross-sectional view of the backlight assembly illustrated in FIG. 1.

1 and 2, a backlight assembly 700 according to an embodiment of the present invention includes first and second lamps 100 and 200 and a reflective member 300.

A plurality of first lamps 100 are arranged in parallel to each other on. The first lamp 100 generates light in response to the driving power applied from the outside. The first lamps 100 are preferably arranged at equal intervals. Here, the number of the first lamps 100 may vary depending on the luminance characteristics.

For example, the first lamp 100 may include a cold cathode fluorescent lamp (CCFL). The first lamp 100 includes a lamp body made of glass, an internal electrode disposed inside the lamp body to apply a discharge voltage, and a fluorescent film formed on an inner wall of the lamp body. The discharge gas for emitting light is injected into the inner space of the lamp body. The fluorescent film is excited by the ultraviolet rays generated by the discharge gas through the plasma discharge to emit visible light 110. In contrast, the first lamp 100 may be formed of an external electrode fluorescent lamp (EEFL) having external electrodes formed at both ends thereof.

The second lamp 200 generates light in response to the driving power applied from the outside. The second lamp 200 has the same structure as the first lamp 100, but generates the infrared light 210 by changing the material of the discharge gas or the fluorescent film.

In general, the infrared light 210 has a longer wavelength and a smaller frequency than the visible light 110. Infrared light 210 is not visible with the naked eye, such as visible light (110).

The diameter of the second lamp 200 is shorter than the first lamp 100. Alternatively, the diameter of the second lamp 200 may have the same length as the one lamp 100.

The second lamp 200 is disposed between the first lamps 100. For example, one first lamp 100 is disposed at both sides of the second lamp 200. Alternatively, two or more first lamps 100 may be disposed on both sides of the second lamp 200. The number of the first lamp 100 and the second lamp 200 has a ratio between 1: 0.1 and 1: 1.

The reflective member 300 is disposed under the first and second lamps 100 and 200. The reflective member 300 includes a base substrate 310 and a semiconductor fluorescent layer 320 formed on an upper surface of the base substrate 310.

The semiconductor fluorescent layer 320 is made of a semiconductor material that generates light in response to energy supplied from the outside. For example, the semiconductor fluorescent layer 320 is made of a semiconductor that reacts with light energy. Alternatively, the semiconductor fluorescent layer 320 may be formed of a semiconductor that reacts to thermal energy and electrical energy.

Most of the visible light 110 generated from the first lamps 100 is reflected by the semiconductor fluorescent layer 320 to generate the visible light 120 again, while a part of the visible light 110 is the semiconductor fluorescent layer Absorbed at 320.

The semiconductor fluorescent layer 320 generates visible light 220 in response to the infrared light 210 generated from the second lamp 200. In detail, the semiconductor fluorescent layer 320 generates the visible light 220 by supplying infrared light 210, that is, light energy, to light absorbed by the semiconductor fluorescent layer 320.

The backlight assembly 700 further includes a diffusion plate 400 disposed on the first and second lamps 100 and 200 and an optical sheet 500 disposed on the diffusion plate 400.

The diffuser plate 400 diffuses the light generated from the lamps to improve the brightness uniformity of the light. The diffusion plate 400 has a plate shape having a predetermined thickness. The diffusion plate 400 is made of a transparent material for transmitting light, and includes a diffusion agent for diffusing light. The diffusion plate 400 is made of, for example, polymethyl methacrylate (PMMA) material.

The optical sheet 500 changes the path of the light diffused through the diffusion plate 400 once again to improve luminance characteristics. The optical sheet 500 may include a light collecting sheet for condensing the light diffused through the diffusion plate 400 in the front direction to improve the front brightness of the light. In addition, the optical sheet 500 may further include a diffusion sheet for diffusing the light diffused through the diffusion plate 400 once again. Meanwhile, an optical sheet 500 having various functions may be further added to the backlight assembly 700 according to required luminance characteristics.

In addition, the backlight assembly 700 further includes a storage container 600 accommodating the first lamps 100, the second lamps 200, and the reflective member 300.

The storage container 600 includes a bottom surface 610 and sidewalls 620 extending or disposed from the bottom surface 610. The storage container 600 has a storage space formed by the bottom surface 610 and the sidewalls 620 to accommodate the first lamps 100, the second lamp 200, and the reflective member 300.

FIG. 3 is a cross-sectional view illustrating a path in which visible light is reflected in the semiconductor fluorescent layer illustrated in FIG. 1.

Referring to FIG. 3, the semiconductor fluorescent layer 320 is composed of electrons 330 including the valence 332 and the excitation electron 334.

The electrons 330 are electrically negative. The electrons 330 have energy of various magnitudes. In general, the electrons 330 are in an unstable state when the magnitude of energy is large, and thus emits a certain amount of energy to stabilize itself. Here, energy release takes many forms. For example, energy release is in the form of generating visible light.

The electrons 330 include the valence electron 332 which is in an energy stable state, and the excitation electron 334 in which the valence electron 332 is excited by the visible light 110.

The excitation electron 334 is in an energy unstable state. Therefore, the excitation electron 334 is about to change into the valence 332 which is itself stable. At this time, the excitation electron 334 is changed to the valence electron 332 by the collision and electrical repulsive force of the neighboring excitation electron 334. The excitation electron 334 is changed into the valence electron 332 to generate the visible light 120. Visible light 120 is emitted upwards, the direction is emitted is irregular.

As such, the visible light 110 excites the valence electrons 332 included in the semiconductor fluorescent layer 320 to be converted into excitation electrons 334, and the excitation electrons 334 are changed back to the valence electrons 332. As the visible light 120 is generated, as a result, the semiconductor fluorescent layer 320 serves to reflect the visible light 110.

4 is a cross-sectional view illustrating a path in which visible light is generated by infrared light in the semiconductor fluorescent layer shown in FIG. 1.

Referring to FIG. 4, the semiconductor fluorescent layer 320 is composed of electrons 330 including a valence electron 332, an excitation electron 334, and a capture electron 336.

The electrons 330 are trapped in the semiconductor fluorescent layer 320 among the electrons 332 in a stable state, the excitation electrons 334 excited by the visible light 110, and the excitation electrons 334. Captured electrons 336.

The trapping electrons 336 are energetically unstable than the valence 332, but have insufficient energy to generate the visible light 120 like the excitation electrons 334 and change into the valence 332. The trapping electrons 336 are formed when some of the visible light 110 is absorbed by the semiconductor fluorescent layer 320.

The trapping electrons 336 are supplied with energy by the infrared light 210 and are converted into the excitation electrons 334. These excitation electrons 334 are about to change into the valence 332 which is itself stable. At this time, the excitation electron 334 is changed to the valence electron 332 by the collision and electrical repulsive force of the neighboring excitation electron 334. The excitation electron 334 is changed into the valence electron 332 to generate the visible light 220. Visible light 220 is emitted upwards, the exit direction is irregular.

As such, the semiconductor fluorescent layer 320 converts the trapped electrons 336 formed by the absorption of the visible light 110 into the semiconductor fluorescent layer 320 to the excitation electrons 334 by the infrared light 210. The excitation electrons 334 are changed back to the valence electrons 332 to generate visible light 220, thereby improving light utilization efficiency of the semiconductor fluorescent layer 320.

5 is an exploded perspective view of a backlight assembly according to another exemplary embodiment of the present invention, and FIG. 6 is a combined cross-sectional view of the backlight assembly illustrated in FIG. 5.

5 and 6, the backlight assembly 750 according to another exemplary embodiment of the present invention may include a first lamp 150 generating visible light 160 and a second lamp generating infrared light 260. 250, a light guide plate 450 disposed on the sides of the first and second lamps 150 and 250, and a lamp cover 180 surrounding the first and second lamps 150 and 250.

The first lamp 150 generates the visible light 160 in response to the driving power applied from the outside. The first lamp 150 is disposed at both sides of the light guide plate 450. Alternatively, the first lamp 150 may be disposed only on one side of the light guide plate 450.

The second lamp 250 generates the infrared light 260 in response to the driving power applied from the outside. The second lamp 250 is disposed at the side of the light guide plate 450 on which the first lamp 150 is disposed. Alternatively, the second lamp 250 may be disposed to face the side of the light guide plate 450 on which the first lamp 150 is disposed.

The light guide plate 450 guides the visible light 160 and the infrared light 260 generated from the first and second lamps 150 and 250 in an upward direction. The light guide plate 450 is made of a transparent material to minimize the loss of light. For example, the light guide plate 450 is made of polymethyl methacrylate (PMMA).

The lamp cover 260 has a shape in which one surface is opened while surrounding the first and second lamps 150 and 250, and a reflective member 350 is formed on an inner surface thereof.

The reflective member 350 includes a base film 360 and a semiconductor fluorescent layer 370 formed on the base film 360. The semiconductor fluorescent layer 370 reflects the visible light 160 and generates the visible light 270 in response to the infrared light 260.

Most of the visible light 160 generated from the first lamps 150 is reflected by the semiconductor fluorescent layer 370 to generate the visible light 170 again, while a part of the visible light 160 is the semiconductor fluorescent layer 370 is absorbed.

The semiconductor fluorescent layer 370 generates visible light 270 in response to the infrared light 260 generated from the second lamps 250. In detail, the semiconductor fluorescent layer 370 generates the visible light 270 by supplying infrared light 260, that is, light energy, to light absorbed by the semiconductor fluorescent layer 370.

The backlight assembly 700 is disposed above the storage container 650 for accommodating the first and second lamps 150 and 250 and the light guide plate 450 and the light guide plate 450 to improve the characteristics of light. And a reflective sheet 660 reflecting light leaking to the lower portion of the light guide plate 450 upward.

7 is a cross-sectional view showing a backlight assembly showing another embodiment of the present invention.

Since FIG. 7 has the same structure as that of FIGS. 5 and 6 except for the structure in which the reflective member is disposed, the same reference numerals are used, and a detailed description thereof will be omitted.

Referring to FIG. 7, in the backlight assembly 760 according to another exemplary embodiment, the reflective member 355 is disposed under the light guide plate 450.

The reflective member 355 includes a base film 365 and a semiconductor fluorescent layer 375 formed on an upper surface of the base film 365. The semiconductor fluorescent layer 375 reflects the visible light 165 and generates the visible light 275 in response to the infrared light 265.

Most of the visible light 165 generated from the first lamps 150 and leaked to the lower portion of the light guide plate 450 is reflected by the semiconductor fluorescent layer 375 to generate the visible light 175 again, while the visible light is emitted. A portion of 165 is absorbed in the semiconductor fluorescent layer 375.

The semiconductor fluorescent layer 375 generates visible light 275 in response to the infrared light 265 generated from the second lamps 250. In detail, the semiconductor fluorescent layer 375 generates the visible light 275 by supplying infrared light 265, that is, light energy, to light absorbed by the semiconductor fluorescent layer 375.

In addition, the backlight assembly 750 reflects the visible light 160 and the infrared light 260 generated from the first and second lamps 150 and 250 on the inner surface of the lamp cover 185 and enters the light guide plate 450. The reflective film 186 is formed to make it.

8 is an exploded perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 8, the liquid crystal display 1000 according to the exemplary embodiment may include a backlight assembly 700 for supplying light, a display unit 800 for displaying an image using the light, and a display unit 800. A top chassis 900 for fixing).

In the present embodiment, since the backlight assembly 700 has the same structure as shown in FIGS. 1 to 4, the same reference numerals are used, and detailed description thereof will be omitted.

The display unit 800 includes a liquid crystal display panel 810 for displaying an image and a driving circuit unit 820 for driving the liquid crystal display panel 810.

The liquid crystal display panel 810 is injected between the array substrate 812 for displaying pixels, the color filter substrate 814 facing the array substrate 812, and the array substrate 812 and the color filter substrate 814. It includes a liquid crystal layer (not shown).

The array substrate 812 is a TFT substrate in which thin film transistors (hereinafter referred to as TFTs) as switching elements are formed in a matrix form. A data line and a gate line are respectively connected to the source terminal and the gate terminal of the TFTs, and a pixel electrode made of a transparent conductive material is connected to the drain terminal.

In the color filter substrate 814, RGB pixels for implementing colors are formed in a thin film form. The common electrode made of a transparent conductive material is formed on the color filter substrate.

In the liquid crystal display panel 810 having such a configuration, when power is applied to the gate terminal of the TFT and the TFT is turned on, an electric field is formed between the pixel electrode and the common electrode. Such an electric field changes the arrangement of the liquid crystal molecules of the liquid crystal layer interposed between the array substrate 812 and the color filter substrate 814, and changes the transmittance of light supplied from the backlight assembly 700 according to the change of the arrangement of the liquid crystal molecules. The image of the desired gradation is displayed.

The driving circuit unit 820 may include a data printed circuit board 822 for supplying a data driving signal to the liquid crystal display panel 810, a gate printed circuit board 824 for supplying a gate driving signal to the liquid crystal display panel 810, and data printing. A data driving circuit film 826 connecting the circuit board 822 to the liquid crystal display panel 810, and a gate driving circuit film 828 connecting the gate printed circuit board 824 to the liquid crystal display panel 810. .

The data driving circuit film 826 and the gate driving circuit film 828 are formed of, for example, a tape carrier package (TCP) or a chip on film (COF). Meanwhile, the gate printed circuit board 824 may be removed by forming separate signal lines on the liquid crystal display panel 810 and the gate driving circuit film 828.

The top chassis 900 is coupled to the storage container 600 to fix the edge of the liquid crystal display panel 810. In this case, the data printed circuit board 822 is bent by the data driving circuit film 826 and fixed to the bottom surface 610 or sidewall 620 of the storage container 600. The top chassis 900 is made of, for example, a metal having little deformation and excellent strength.

According to such a backlight assembly and a liquid crystal display having the same, a visible light incident from an upper portion of the reflective member is formed by forming a semiconductor fluorescent layer on an upper surface of the reflective member and disposing a separate lamp thereon to generate infrared light. Reflected light is partially reflected and absorbed into the semiconductor fluorescent layer by infrared light. Therefore, the utilization efficiency of light can be improved and luminance can be increased.

Although the detailed description of the present invention has been described with reference to the preferred embodiments of the present invention, those skilled in the art or those skilled in the art will have the idea of the present invention 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 (10)

At least one first lamp generating first visible light; At least one second lamp for generating infrared light; And And a reflective member reflecting the first visible light and having a semiconductor fluorescent layer that generates a second visible light in response to the infrared light. The method of claim 1, A plurality of the first lamps are disposed in parallel to each other on the reflective member, And the reflective member is disposed under the first and second lamps. The backlight assembly of claim 2, wherein the second lamp is disposed between the first lamps. The backlight assembly of claim 2, wherein the number ratio of the first lamps to the second lamps is in a range of about 1: 0.1 to about 1: 1. The backlight assembly of claim 2, wherein the semiconductor fluorescent layer is formed on an upper surface of the reflective member. The method of claim 2, Diffuser plates disposed above the first and second lamps; And The backlight assembly further comprises an optical sheet disposed on the diffusion plate. The method of claim 1, A light guide plate disposed at sides of the first and second lamps; And And a lamp cover surrounding the first and second lamps. The backlight assembly of claim 7, wherein the reflective member is formed on an inner surface of the lamp cover. The backlight assembly of claim 7, wherein the reflective member is disposed under the light guide plate. A backlight assembly for supplying light; A display unit including a liquid crystal display panel for displaying an image using light from the backlight assembly and a driving circuit unit for driving the liquid crystal display panel; And A top chassis fixing the display unit, The backlight assembly, At least one first lamp generating first visible light, At least one second lamp for generating infrared light, and And a reflecting member reflecting the first visible light and having a semiconductor fluorescent layer that generates a second visible light in response to the infrared light.

Images