KR20050100930A - A liquid crystal display provided with an improved capability for radiating beams - Google Patents

Abstract

The present invention relates to a liquid crystal display device in which the shape of the light guide plate is modified to improve light emission characteristics. To this end, the liquid crystal display device of the present invention includes a liquid crystal display panel assembly in which an image is displayed and a backlight assembly having at least one light emitting diode LED for supplying light to the liquid crystal display panel assembly and a light guide plate for guiding the light. Light emitted from the diode is incident on the light incident portion formed on one side of the light guide plate, and a plurality of protrusions corresponding to the light are formed on the light incident portion. Through the present invention, light may be refracted at various angles to minimize dark area and at the same time, uniform light may be supplied over the entire liquid crystal display panel.

Description

Liquid crystal display with improved light emission characteristics {A LIQUID CRYSTAL DISPLAY PROVIDED WITH AN IMPROVED CAPABILITY FOR RADIATING BEAMS}

The present invention relates to a liquid crystal display device having improved light emission characteristics, and more particularly, to a liquid crystal display device having improved light emission characteristics by modifying a shape of a light guide plate.

With the recent development of semiconductor technology, which is rapidly developing in recent years, the demand for flat panel display devices that are smaller and lighter and has improved performance is exploding.

The liquid crystal display (LCD), which has recently been in the spotlight among the flat panel display devices, has advantages such as miniaturization, light weight, and low power consumption, thereby overcoming the disadvantages of the conventional cathode ray tube (CRT). As an alternative means, it has been gradually 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 display apparatus which displays information using the modulation of the light by a liquid crystal cell as converting into a change.

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 under the liquid crystal display panel. In the case of a small liquid crystal display panel used in a mobile product such as a mobile phone, a small light emitting diode (LED) is used as a backlight due to space constraints. Since the light emitting diode is a semiconductor device, it has a long life, a fast ignition speed, low power consumption, strong impact resistance, and suitable for miniaturization and thin film, and is also a means for gradually replacing lamps used in small and medium-sized LCD products. Is being developed.

However, the light emitting diode has a disadvantage in that light cannot be emitted from the light emitting diode in all directions due to the characteristics of the light emitting diode. In particular, in the case of LCD products using three light emitting diodes of red (R), green (G), and blue (B), a hot spot is formed around the light emitting diodes between the light emitting diodes due to the light emission angle limit. There is a problem that is formed to lower the display characteristics of the LCD product.

The present invention is to solve the above-mentioned problems, to modify the shape of the light guide plate for guiding the light emitted from the light emitting diode to improve the radiation characteristics of the light.

According to an aspect of the present invention, there is provided a liquid crystal display device including: a liquid crystal display panel assembly in which an image is displayed; and a backlight assembly including at least one light emitting diode for supplying light to the liquid crystal display panel assembly and a light guide plate for guiding the light. It includes a (light backlight assembly), the light emitted from the light emitting diode is incident to the light incident portion formed on one side of the light guide plate, a plurality of protrusions corresponding to the light is formed in the light incident portion.

Here, it is preferable that the light incidence portion is formed in the light guide plate in a concave shape as a whole, and the front end of the light emitting diode protrudes into the light incidence portion.

In addition, the light incidence portion is formed by opposing surfaces opposing the front end and the front surface of the light emitting diode and side surfaces connected to the opposing surfaces on both sides of the opposing surface, and the side surfaces are formed in a notch shape protruding toward the center of the light incidence portion. Can be formed.

The light incidence part may be formed on the opposing surface opposing the front end and the front surface of the light emitting diode and the side surfaces connected to the opposing surface on both sides of the opposing surface, and the width between the sides may be narrower as the opposing surface is closer to the opposing surface.

In addition, the light incident part may be formed in an arc shape.

In addition, a plurality of light emitting diodes may be arranged in an array.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 5. These embodiments of the present invention are merely for illustrating the present invention, but the present invention is not limited thereto.

1 is an exploded perspective view of a liquid crystal display device according to a first embodiment of the present invention, which illustrates a liquid crystal display device used in a mobile LCD product such as a cellular phone.

The liquid crystal display device 100 according to the first exemplary embodiment of the present invention shown in FIG. 1 includes a backlight assembly 20 for supplying light and a liquid crystal display panel assembly 70 in which an image is displayed by receiving light. Is made of. In addition, a top chassis 60, a mold frame 22, and a bottom chassis 28 for fixing and holding them are provided. The backlight assembly 20 illustrated in FIG. 1 supplies and guides light to the liquid crystal display panel assembly 70, and the liquid crystal display panel assembly 70 positioned on the backlight assembly 20 displays an image. Control 75.

The liquid crystal display panel assembly 70 includes a liquid crystal display panel 75, an integrated circuit chip (IC chip) 77, and a flexible printed circuit board (FPC) 79.

The liquid crystal display panel 75 includes a TFT substrate 73 composed of a plurality of TFTs (thin film transistors), a color filter substrate 71 positioned on the TFT substrate 73, and a liquid crystal injected between these substrates ( Not shown). The integrated circuit chip 77 is mounted on the TFT substrate 73 to control the liquid crystal display panel 75.

The TFT substrate 73 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.

The data line and gate line of the liquid crystal display panel 75 described above are connected to the flexible printed circuit board 79, and when an electrical signal is input from the flexible printed circuit board 79, electrical signals are input to the source terminal and the gate terminal of the TFT. The TFTs are turned on or off in accordance with the input of these electrical signals, and the electrical signals necessary for pixel formation are output to the drain terminal. The flexible circuit board 79 receives an image signal from the outside of the liquid crystal display panel 75 and applies driving signals to data lines and gate lines of the liquid crystal display panel 75, respectively.

On the other hand, a color filter substrate 71 is disposed thereon facing the TFT substrate 73. The color filter substrate 71 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 71 and the color filter substrate 73 is changed, and the light transmittance is changed according to the changed arrangement angle to obtain a desired pixel.

The flexible printed circuit board 79 generates a data signal, a gate driving signal, which are signals for driving the liquid crystal display device 100, and a plurality of timing signals for applying these signals at an appropriate time, and the gate driving signal and data driving. The signal is applied to the gate line and the data line of the liquid crystal display panel 75, respectively.

A backlight assembly 20 is provided below the liquid crystal display panel assembly 70 to provide uniform light to the liquid crystal display panel assembly 70 and is stored on the bottom chassis 28.

One or more light emitting diodes (12) fixed to the mold frame (22) and supplying light to the liquid crystal display panel assembly (70), a substrate (14) supplying power to the light emitting diodes (12), and emitting from the light emitting diodes (12). The light guide plate 10 for guiding the light to be supplied to the liquid crystal display panel assembly 70, the reflective sheet 26 positioned at the lower front surface of the light guide plate 10 to reflect the light, and the luminance of the light from the light emitting diode 12. An optical sheet 24 is provided for securing the characteristics to the liquid crystal display panel assembly 70.

Although not shown in FIG. 1, an inverter board, which is a power supply PCB, and a signal conversion PCB are installed on the bottom of the bottom chassis 28. The inverter board transforms an external power supply to a constant voltage level and provides the LED 12 with a signal conversion PCB. The PCB for signal conversion is connected to the flexible circuit board 79 to convert an analog data signal into a digital data signal, thereby converting an LCD into a liquid crystal display panel 75. To provide.

The top chassis 60 for preventing the liquid crystal display panel assembly 70 from being separated from the bottom chassis 28 while bending the flexible circuit board 79 to the outside of the mold frame 22 on the liquid crystal display panel assembly 70. It is provided. Although not shown in FIG. 1, a front case and a rear case are positioned at an upper portion of the top chassis 60 and a lower portion of the bottom chassis 28, respectively, to form a liquid crystal display device 100 by combining them.

In the first embodiment of the present invention, as shown in the enlarged circle of FIG. 1, a light incidence portion 102 having a concave shape is formed on one side of the light guide plate 10, and is emitted from the light emitting diode 12. Light is incident through the light incident part 102. The light incident part 102 is formed in a concave shape as a whole to narrow the distance from the light emitting diode 12. As a result, the loss of light due to space is reduced, so that the luminance characteristic of the light can be further improved.

Although the light guide plate 10 of FIG. 1 is illustrated as having three light incidence portions 102 formed therein, this is merely to illustrate the present invention and the present invention is not limited thereto. Accordingly, in the case of LCD products requiring a plurality of light emitting diodes, a plurality of light incident portions may be formed in the light guide plate.

As shown in the enlarged source of FIG. 1, a plurality of protrusions 104 corresponding to the light emitted from the light emitting diodes 12 are formed in the light incident part 102 in an embossing form. Light emitted from the light emitting diode 12 is refracted at various angles due to the protrusion 104. Therefore, the light can be guided to the dark portion between the light emitting diodes 104, which cannot reach the light due to the light emission angle limit of the light emitting diodes 104, so that uniform light can be supplied throughout the entire liquid crystal display panel.

FIG. 2 is a rear perspective view of the liquid crystal display according to the first exemplary embodiment of the present invention. FIG. 2 is a view illustrating the liquid crystal display shown in FIG. In FIG. 2, for convenience of description of the shape of the light guide plate 10, illustration of the reflective sheet 26 and the bottom chassis 28 of FIG. 1 is omitted. In addition, below, the closest part of a light emitting diode with respect to a light guide plate is called a front end.

As shown in FIG. 2, in the first embodiment of the present invention, the front end 122 of the light emitting diode 12 protrudes into the light incident part 102. In the present invention, the distance between the light emitting diodes 12 and the light guide plate 10 is as close as possible through this method, thereby greatly reducing the space between the two, thereby minimizing the difference in refractive index of the light emitted from the light emitting diodes 12, and thus the loss of luminance. Can also be minimized.

As shown in FIG. 2, the light incident part 102 includes an opposing surface 106 facing the front end 122 of the light emitting diode 12 from the front surface, and opposing surfaces (both sides of the opposing surface 106). 106 is formed with a side surface 108. Here, the side surface 108 is formed in the shape of a notch protruding toward the center of the light incident portion 102. Since the light is refracted at various angles through the structure of the light incident part 102, the dark part generating area can be minimized.

3 is a rear perspective view of the liquid crystal display 300 according to the second exemplary embodiment of the present invention, except for the shape of the light incident part 302 formed on one side of the light guide plate 30. Same as the example. Therefore, the same parts as those in the first embodiment of the present invention will be omitted, and the description will be given focusing on the light guide plate 30 different from the first embodiment of the present invention.

In FIG. 3, the light incident part 302 formed on one side surface of the light guide plate 30 includes an opposing surface 306 facing the front end 122 of the light emitting diode 12 from the front surface, and both sides of the opposing surface 306. It is formed by the opposing face 306 and the lateral side 308 connected, and the width between the lateral face 308 becomes narrower as it gets closer to the opposing face 306. On the opposing surface 306 and the side surface 308 forming the light incident portion 302, a plurality of protrusions 304 are formed in an embossed shape.

In the light incident part 302, the width between the side surfaces 308 is formed to become narrower as the opposite surface 306 gets closer, so that the light emitted from the light emitting diode 12 is refracted at various angles. 12) It is possible to minimize the dark areas generated between.

4 is a rear perspective view of the liquid crystal display 400 according to the third exemplary embodiment of the present invention, except for the shape of the light incident part 402 formed on one side of the light guide plate 40. Same as the example. Therefore, the same parts as those in the first embodiment of the present invention will be omitted, and the description will be given focusing on the light guide plate 40 different from the first embodiment of the present invention.

In FIG. 4, the light incident part 402 is formed in an arc shape, and a plurality of protrusions 404 are formed to correspond to the light emitted from the light emitting diode 12. Such a structure can easily refract the light emitted from the light emitting diodes 12 at various angles, and also facilitate the fabrication process when the light incident part is formed on the light guide plate 40.

FIG. 5 is an exploded perspective view of a liquid crystal display device 500 according to a fourth embodiment of the present invention, and shows an example in which the present invention is applied to small and medium-sized LCD products such as notebook computers, and the basic structure thereof is the same as that of the first embodiment of the present invention. . Therefore, the same parts as those in the first embodiment of the present invention will be omitted, and the description will be mainly given for parts different from the first embodiment of the present invention. The structure of the liquid crystal display shown in FIG. 5 is merely for illustrating the present invention, and the present invention is not limited thereto. Therefore, the liquid crystal display device may be modified into another structure.

The liquid crystal display device 500 according to the fourth exemplary embodiment of the present invention includes a liquid crystal display panel 95 on which an image is displayed, and the gate line and the data line of the liquid crystal display panel 95 each use a separate PCB and TCP. It is connected through. The data line and the gate line are electrically connected to the data PCB (printed circuit board) 96 and the gate PCB 94 through the data TCP 99 and the gate TCP 97, respectively, to drive signals and timing signals. Receive the back. The backlight assembly including the light emitting diode 12 is received in the bottom chassis 58 and fixed to the mold frame 59. The edge of the liquid crystal display panel 95 is surrounded by the top chassis 65 to be combined and protected.

In the LCD 500 according to the fourth embodiment of the present invention, a plurality of light emitting diodes 12 are attached to a substrate 54 and then fixed to a middle mold frame 55 to form an array. It can be formed as. Since medium and large LCD products have a large image display area, it is suitable to use a plurality of light emitting diodes 12 arranged in an array form in order to improve display quality. In order to obtain high brightness, as shown in the enlarged circle of FIG. 5, it is preferable to form a light concave portion 502 which is concave entirely on one side of the light guide plate 50, and to form a plurality of protrusions 504. Although the light incident part 502 of FIG. 5 faces in the Y-axis direction, for explanation of the internal shape, in the enlarged circle of FIG. Shown.

The shape of the light incidence portion 502 formed in the light guide plate 50 in the fourth embodiment of the present invention shown in FIG. 5 is shown in the light guide plate 10 (FIGS. 1 and 2) in the first embodiment of the present invention. Is the same as the shape of the light incident part 102 (shown in FIG. 1 and FIG. 2) formed in FIG. Although not shown, the light incidence part 502 can also be modified into the light incidence part of the second embodiment of the present invention and the light incidence part of the third embodiment of the present invention.

As described above, in the liquid crystal display according to the present invention, a plurality of protrusions corresponding to the light are formed on the light incident part formed on one side of the light guide plate to refract the light at various angles, thereby providing a dark part between the light emitting diodes. By guiding the light up to uniform light can be supplied over the entire liquid crystal display panel.

In addition, the front end of the light emitting diode may be projected into the light incident part to minimize the distance between the light emitting diode and the light guide plate, thereby reducing the difference in the refractive index of the emitted light, thereby reducing the loss of luminance.

In addition, the light incident part may be formed as an opposite surface facing the light emitting diode and a side surface connected to both sides, and the side may be formed in a notch shape, thereby minimizing dark areas by refraction of light at various angles.

In addition, the light incidence part may be formed of an opposing surface facing the light emitting diode and a side surface connected to both sides, and the width between the sides may be narrower as it approaches the opposing surface, thereby minimizing dark areas by refraction of light at various angles. .

In addition, the light incident part of the light emitting diode may be formed in an arc shape, and light may be refracted at various angles, thereby minimizing dark areas.

In addition, in the present invention, since an array may be formed by arranging a plurality of light emitting diodes, there is an advantage that it is easy to apply to small and medium-sized LCD products.

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.

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

2 is a rear perspective view of the liquid crystal display according to the first embodiment of the present invention.

3 is a rear perspective view of a liquid crystal display according to a second exemplary embodiment of the present invention.

4 is a rear perspective view of a liquid crystal display according to a third exemplary embodiment of the present invention.

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

Claims (6)

A liquid crystal display panel assembly in which an image is displayed, and A backlight assembly having at least one light emitting diode (LED) for supplying light to the liquid crystal display panel assembly and a light guide plate for guiding the light. Including, The light emitted from the light emitting diode is incident to the light incident portion formed on one side of the light guide plate, and a plurality of protrusions corresponding to the light is formed in the light incident portion. In claim 1, And the light incidence part is formed in the light guide plate in a concave shape as a whole, and a front end of the light emitting diode protrudes into the light incidence part. In claim 2, The light incidence part is formed of an opposing surface opposing the front end and the front surface of the light emitting diode, and a side surface connected to the opposing surface on both sides of the opposing surface, The side surface of the liquid crystal display device is formed in the shape of a notch protruding toward the center of the light incident portion. In claim 2, The light incidence part is formed of an opposing surface opposing the front end and the front surface of the light emitting diode, and a side surface connected to the opposing surface on both sides of the opposing surface, And a width between the side surfaces narrows closer to the opposite surface. In claim 2, The light incidence part is formed in an arc shape. In claim 2, And a plurality of light emitting diodes arranged in an array.