KR20060079708A - A backlight assembly and a flat display device provided with the same - Google Patents

Abstract

The present invention relates to a backlight assembly having an improved structure of a surface light source, and a flat panel display device having the same. To this end, the backlight assembly according to the present invention includes a bottom chassis including a surface light source for supplying light generated from the channel and an inner space for accommodating the surface light source, including a plurality of channels arranged side by side with electrodes at both ends. Include. In addition, the surface light source forms a spaced space spaced apart from the bottom chassis in the width direction of the channel, and a portion of the light emitted from the surface light source is reflected and emitted through the spaced space.

Backlight assembly, surface light source, liquid crystal display, separation space

Description

Back light assembly and flat panel display device having same {A BACKLIGHT ASSEMBLY AND A FLAT DISPLAY DEVICE PROVIDED WITH THE SAME}

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

2 is a partially coupled perspective view of a backlight assembly according to an embodiment of the present invention.

3 is a cross-sectional view taken along line AA of FIG. 2.

4 is an exploded perspective view of a flat panel display device according to an exemplary embodiment of the present invention.

5 (a) is a graph showing the luminance distribution of the experimental example according to the present invention, Figure 5 (b) is a graph showing the luminance distribution of the comparative example according to the prior art.

The present invention relates to a backlight assembly with improved brightness and a flat panel display device having the same, and more particularly, to a backlight assembly having improved brightness by modifying a structure of a backlight assembly for supplying light and a flat panel display device having the same. will be.

With the recent development of semiconductor technology, which is rapidly developing in recent years, the demand for liquid crystal display devices having improved performance while being miniaturized and lightweight has exploded.

Recently, liquid crystal displays (LCDs), which have been in the spotlight, have advantages such as miniaturization, light weight, and low power consumption, and as an alternative means to overcome the disadvantages of the conventional cathode ray tube (CRT). It has been attracting attention and is currently used in almost all information processing equipment that requires a display device.

A general liquid crystal display device applies voltage to a specific molecular array of a liquid crystal to convert it into another molecular array, and visually changes optical properties such as birefringence, photoreactivity, dichroism, and light scattering characteristics of the liquid crystal cell emitted by the molecular array. It is a light-receiving display device which converts into a change and displays information using the modulation of the light by a liquid crystal cell.

Since the liquid crystal display panel of the liquid crystal display device does not emit light by itself, the liquid crystal display panel includes a backlight for providing light to the liquid crystal display panel from under the liquid crystal display panel. In a large liquid crystal display such as a digital TV, a plurality of tubular lamps are used as backlights. In this case, many components are used, which causes a complicated assembly process. In addition, there is a problem in that uniformity is poor because light is not uniformly supplied to the liquid crystal display panel.

Therefore, as the size of the liquid crystal display device gradually increases, securing high luminance and excellent screen uniformity is of paramount importance. Therefore, a flat panel display device employing a surface light source has been developed to compensate for the shortcomings of the tubular lamp.

However, when a surface light source is used in a large TV, a problem arises in that the upper, lower and corners of the surface light source are adjacent to the fixing member of the surface light source. Conventionally, in order to solve such a problem, the structure which improves the brightness | luminance is employ | adopted by enlarging the width | variety and the length of the electrode installed in the uppermost and the lowermost, and let high current flow. However, this conventional structure has a problem that the luminance is reduced in the upper, lower and corners of the surface light source by blocking the light emitted from the relatively wide electrode.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a backlight assembly and a flat panel display including the same, by improving the structure of the backlight assembly and improving brightness while minimizing internal light loss.

The backlight assembly according to the present invention for achieving the above object includes a surface light source for supplying light generated in the channel, including a plurality of channels arranged side by side with electrodes at both ends, and the surface light source And a bottom chassis having an inner space for accommodating the light source, wherein the surface light source forms a spaced space spaced apart from the bottom chassis in the width direction of the channel, and a part of the light emitted from the surface light source is reflected and spaced apart. It is emitted through space.

Here, the backlight assembly is provided with a reflector between the bottom chassis and the surface light source, and reflects a part of the light emitted from the surface light source by the reflecting plate to emit through the space.

In addition, the reflector may be made of at least one material selected from the group consisting of PC (poly carbonate, polycarbonate), PET (polyethylene terephthalate, polyethylene terephthalate) and PMMA (polymethyl methacrylate, polymethyl methacrylate).

In addition, the reflector is preferably installed over the entire inner space of the bottom chassis.

The reflector is spaced apart from the surface light source.

Further, the distance between the reflecting plate and the surface light source is gradually closer to both ends of the channel in the width direction.

The width of the separation space along the width direction of the channel is preferably formed to be 2% to 8% of the length of the surface light source in the width direction of the channel.

In addition, the flat panel display device according to the present invention includes a flat panel display panel for displaying an image, and the backlight assembly described above.

In the flat panel display device according to the present invention, the flat panel display panel is preferably a liquid crystal display panel.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4. These embodiments of the present invention are merely for illustrating the present invention, but the present invention is not limited thereto.

The structure of the backlight assembly 70 shown in FIG. 1 is merely to illustrate the present invention, but the present invention is not limited thereto. Therefore, the present invention can be applied to the backlight assembly 70 having another structure.

The backlight assembly 70 according to the exemplary embodiment of the present invention shown in FIG. 1 is fixed by a bottom chassis 64 positioned below and a mold frame 62 positioned above. The backlight assembly 70 is installed at the bottom of the surface light source 76 and the surface light source 76 fixedly spaced apart from the bottom chassis 64 by a predetermined distance, and fixes the surface light source 76 to the bottom chassis 64. And a support member 77 spaced apart from the planar light source 76, a reflector 78 installed at the bottom chassis 64 to reflect light supplied from the planar light source 76, and a liquid crystal display panel by securing the luminance characteristic of the light. The optical sheet 72 and the diffuser plate 74 which provide light to 50 are provided.

Although not shown in FIG. 1, when looking at the internal structure of the surface light source 76, the surface light source 76 is formed on the bottom glass forming the bottom and the length of the bottom glass on the bottom glass to emit visible light. A plurality of channels 761 are provided. In addition, the channels 761 extend along the X-axis direction, and a plurality of channels 761 are arranged along the Y-axis direction.

A reflective layer for reflecting light is formed on the bottom of the channel 761, and a top glass formed in an arc shape is provided on the reflective layer. In addition, a phosphor layer that emits visible light is applied to the inner surface of the top glass and the upper surface of the reflective layer, and electrodes that emit electrons are provided at both ends in the longitudinal direction of the channel 761. The structure of the surface light source is only one embodiment of the present invention, and the present invention is not limited thereto.

The bottom chassis 64 is formed in a structure capable of receiving a surface light source, and the bottom of the bottom chassis 64 is provided with a reflector 78 reflecting light emitted from the surface light source 76 to the bottom. In addition, a support member 77 is provided between the surface light source 76 and the reflecting plate 78 to fix the surface light source 76 apart from the reflecting plate 78.

In addition, the width of the surface light source 76 along the Y-axis direction is smaller than the inner width of the bottom chassis 64 to form a space between the side surfaces of the surface light source 76 in the width direction and the inner surface of the bottom chassis. .

Accordingly, light emitted from the bottom of the surface light source 76 may be reflected by the reflector 78 and emitted upward through the space S (shown in FIG. 2).

FIG. 2 is a partially coupled perspective view of the backlight assembly 70 according to an embodiment of the present invention, and illustrates internal components of the backlight assembly 70 shown in FIG. 1.

As shown in FIG. 2, a space S is formed between the widthwise both ends of the surface light source 76 and the side surface of the bottom chassis 64, and the width of the space S is the surface light source 76. It is preferable to form so that it may become 2%-8% of the width | variety.

If the width of the separation space S is made smaller than 2% of the width of the surface light source 76, the width of the separation space S is too small so that the light reflected from the bottom cannot be sufficiently transmitted to the upper portion, and is larger than 8%. When formed, the width of the surface light source 76 is relatively reduced so that the luminance decreases due to a decrease in the intensity of the emitted light.

FIG. 3 is a cross-sectional view taken along the line AA of FIG. 2, and shows an advancing direction of some light emitted from the surface light source 76. The reflector 78 installed on the bottom chassis 64 is selected from the group consisting of polycarbonate (PC), polyethylene terephthalate (PET), and polymethyl methacrylate (PMMA). It may be made of one or more materials.

Since these materials are transparent materials and have a larger refractive index than air, when the light is incident from the air into the reflecting plate, the refractive angle is larger than the incident angle. Therefore, as the light is repeatedly reflected, the angle of incidence and the angle of refraction become larger and easier to emit light laterally.

The reflecting plate 78 forms a central portion lower than both ends. Therefore, as shown in FIG. 2, the light emitted downward from the surface light source 76 is incident on the upper surface of the reflector 78 at a predetermined angle, and is further refracted laterally. Accordingly, the light emitted to the rear surface of the surface light source 76 can be emitted upward through the separation space (S).

In addition, the reflector 78 is provided over the entire inner space of the bottom chassis 64. Therefore, not only the light incident on the bottom surface of the bottom chassis 64 but also the light directed toward the side surface of the bottom chassis 64 are reflected, so that all the light exiting the rear surface of the surface light source 76 is emitted to the front.

4 is an exploded perspective view of a flat panel display device 100 according to an exemplary embodiment of the present invention, and illustrates a flat panel display device having the backlight assembly 70 illustrated in FIG. 1.

Although the liquid crystal display panel 50 is shown as an example of a flat panel display panel in FIG. 4, this is merely to illustrate the present invention and the present invention is not limited thereto. Accordingly, other types of light receiving flat panel display panels may be used.

The flat panel display device 100 according to an exemplary embodiment of the present invention shown in FIG. 4 includes a backlight assembly 70 for supplying light and a liquid crystal display panel 50 for displaying an image corresponding to the light. In addition, a top chassis 60 fixedly supporting the liquid crystal display panel assembly 40 is provided.

The liquid crystal display panel assembly 40 includes a liquid crystal display panel 50, a COF (chip on film) 43 and 44 connected thereto, and a printed circuit board 41 and 42. Include.

The liquid crystal display panel 50 includes a TFT substrate 51 composed of a plurality of TFTs (thin film transistors), a color filter substrate 53 positioned on the TFT substrate 51, and a liquid crystal injected between the substrates. (Not shown). Polarizing plates are attached to the upper portion of the color filter substrate 53 and the lower portion of the TFT substrate 51 to polarize light passing through the liquid crystal display panel 50.

The TFT substrate 51 is a transparent glass substrate on which a matrix thin film transistor is formed, a data line is connected to a source terminal, and a gate line is connected to a gate terminal. In the drain terminal, a pixel electrode made of transparent indium tin oxide (ITO) as a conductive material is formed.

When electrical signals are input from the printed circuit boards 41 and 42 to the data lines and gate lines of the liquid crystal display panel 50 described above, electrical signals are input to the source and gate terminals of the TFT, Depending on the input, the TFT is turned on or off so that an electrical signal necessary for pixel formation is output to the drain terminal.

On the other hand, the color filter substrate 53 is disposed thereon opposite the TFT substrate 51. The color filter substrate 53 is a substrate in which RGB pixels, which are color pixels in which a predetermined color is expressed while light passes, are formed by a thin film process, and a common electrode made of ITO is coated on the entire surface thereof. When power is applied to the gate terminal and the source terminal of the TFT and the thin film transistor is turned on, an electric field is formed between the pixel electrode and the common electrode of the color filter substrate. By this electric field, the arrangement angle of the liquid crystal injected between the TFT substrate 51 and the color filter substrate 53 is changed, and the light transmittance is changed according to the changed arrangement angle to obtain a desired pixel.

The printed circuit boards 41 and 42 for receiving image signals from the outside of the liquid crystal display panel 50 and applying driving signals to the data lines and the gate lines, respectively, are COFs 43 and 44 attached to the liquid crystal display panel 50. ). The printed circuit boards 41 and 42 generate data signals for driving the flat panel display device 100, gate driving signals, and a plurality of driving signals for applying these signals at appropriate times, thereby generating a gate driving signal and a data driving signal. Is applied to the gate line and the data line of the liquid crystal display panel 50 through the COFs 43 and 44 on which the integrated circuit chips 431 and 441 are mounted.

The backlight assembly 70 is provided below the liquid crystal display panel 50 to provide uniform light to the liquid crystal display panel assembly 40.

On the liquid crystal display panel assembly 40, the liquid crystal display panel assembly 40 is removed from the bottom chassis 64 while bending the data side printed circuit board 42 and the gate side printed circuit board 41 to the outside of the mold frame 62. It is provided with a top chassis 60 to prevent the departure. Although not shown in FIG. 4, the front case and the rear case are positioned at the upper portion of the top chassis 60 and the lower portion of the bottom chassis 64, respectively, to form the flat panel display device 100 by combining them.

Since the flat panel display 100 shown in FIG. 4 includes the backlight assembly 70 described above, light having improved brightness can be supplied to the liquid crystal display panel 50. Accordingly, a clearer image may be realized in the liquid crystal display panel 50.

Hereinafter, the present invention will be described in more detail with reference to experimental examples of the present invention. Such experimental examples of the present invention are merely for illustrating the present invention, and the present invention is not limited thereto.

Experimental Example

After installing a surface light source having 26 channels in a 42-inch model having a structure as shown in FIG. 1, the luminance distribution of light emitted from the first channel located at the edge and the second channel adjacent to the first channel was measured. .

Fig. 5A is a graph showing the luminance distribution according to the experimental example of the present invention, and shows the experimental result.

Comparative example

As a conventional technique, a surface light source was installed on a 42-inch model, and then luminance distribution of light was measured. After the 28-channel surface light source was used to adjoin the surface light source to the bottom chassis without a space, the luminance distribution of the light emitted from the first channel closest to the bottom chassis and the second channel adjacent to the first channel was measured.

FIG. 5B is a graph showing luminance distribution according to a comparative example of the related art, and shows experimental results thereof.

The mountains on the left side of FIGS. 5A and 5B show the luminance distribution of the first channel, and the mountains on the right side show the luminance distribution of the second channel. The synthesized luminance obtained by combining the luminance of these two channels is shown thereon.

In the comparative example of the prior art illustrated in FIG. 5B, it can be seen that the composite luminance decreases between the first channel and the bottom chassis. That is, leakage current is generated between the first channel and the bottom chassis, so that the brightness of the light is significantly reduced. On the other hand, in the experimental example of the present invention, as can be seen from (a) of FIG. 5, the synthesized luminance is kept constant from the first channel toward the edge thereof. That is, it can be observed that the luminance near the edges increases through recycling of the lost light. As described above, the luminance of the surface light source may be improved by modifying the structure of the surface light source, thereby realizing a clearer image.

In the backlight assembly according to the present invention, a space is formed between the surface light source and the bottom chassis, and the light emitted to the rear surface of the surface light source is reflected to the space and emitted upward, thereby increasing the supply of light, thereby improving luminance. .

In addition, by providing a reflector between the bottom chassis and the surface light source, it is possible to efficiently reflect the light emitted to the rear surface of the surface light source.

And since the reflector is made of a material such as PC, PET, and PMMA, it is possible to minimize the loss of light by reflecting the light emitted to the back of the surface light source.

In addition, the reflecting plate is installed in front of the inner space of the bottom chassis to reflect the light incident on the side of the surface light source to increase the light utilization efficiency.

In addition, since the distance between the reflecting plate and the surface light source is closer to both ends of the channel in the width direction, the reflecting plate may easily emit light emitted to the rear surface of the surface light source through the separation space.

The width of the separation space along the width direction of the channel is made of 2% to 8% of the length of the surface light source along the width direction of the channel, so that light can be easily emitted by securing an appropriate separation space.

In addition, the flat panel display device employing the above-described backlight assembly can display a clear image.

Since the liquid crystal display panel can be used as the flat panel display panel used in the flat panel display device, there is an advantage that it can be used universally.

Although the present invention has been described above, it will be readily understood by those skilled in the art that various modifications and variations are possible without departing from the spirit and scope of the claims set out below.

Claims (9)

A surface light source for supplying light generated in the channel, including a plurality of channels arranged side by side with electrodes at both ends, and A bottom chassis having an inner space for accommodating the surface light source Including, The surface light source forms a spaced space spaced apart from the bottom chassis in the width direction of the channel, and a portion of the light emitted from the surface light source is reflected and emitted through the spaced space (backlight assembly). In claim 1, And a reflecting plate disposed between the bottom chassis and the surface light source to reflect a portion of the light emitted from the surface light source by the reflecting plate and to emit the light through the space. In claim 1, The reflector is a backlight assembly consisting of at least one material selected from the group consisting of PC (poly carbonate, polycarbonate), PET (polyethylene terephthalate, polyethylene terephthalate) and PMMA (polymethyl methacrylate, polymethyl methacrylate). In claim 1, And the reflector is installed over the entire interior space of the bottom chassis. In claim 1, The reflector is a backlight assembly formed spaced apart from the surface light source. In claim 5, And a distance between the reflective plate and the surface light source is closer to both ends of the channel in the width direction. In claim 1, The width of the separation space along the width direction of the channel is 2% to 8% of the length of the surface light source along the width direction of the channel. A flat panel display panel displaying an image, and A flat panel display device comprising a backlight assembly according to any one of claims 1 to 7 for supplying light to the flat panel display panel. In claim 8, And the flat panel display panel is a liquid crystal display panel.

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