KR20110016156A - Backlight module and liquid crystal display device having the same - Google Patents

Abstract

PURPOSE: A backlight module and a liquid crystal display device having the same are provided to reduce the power loss and increase the definition of an image by applying a local dimming method. CONSTITUTION: A surface light source unit(210) emits light. A dimming panel(230) is arranged to the light emitting direction of the surface light source unit, divided into matrix shape and includes a plurality of blocks having mutually independent space. Operating electrode and electro-wetting is includes in each block of the dimming panel.

Description

BACKLIGHT MODULE AND LIQUID CRYSTAL DISPLAY DEVICE HAVING THE SAME}

The present invention relates to a backlight module employing a local dimming technique for realizing an image or an image by adjusting the peripheral contrast of an image or an image output through a display, and more particularly, to a liquid crystal display device including the same. The present invention relates to a backlight module and a liquid crystal display including the same.

BACKGROUND ART In general, liquid crystal display devices have tended to be gradually widened due to their light weight, thinness, and low power consumption. In accordance with this trend, liquid crystal displays have been used in office automation equipment, audio / video equipment, and the like. In such a liquid crystal display, a wide transmittance is adjusted according to a signal applied to a plurality of control switches arranged in a matrix to display a desired image on a screen.

In particular, the liquid crystal display (TFT-LCD) has been greatly advanced for many years as a next-generation advanced display device having lower power consumption, lighter weight, and no harmful electromagnetic wave than the cathode ray tube (CRT). In the era of high-definition digital broadcasting, LCD displays (TFT-LCD) along with Plasma DisplayPanel (PDP) are attracting attention as large-screen displays over 30 inches. The development of liquid crystal displays (LCDs) has been devoted. Since the liquid crystal display (TFT-LCD) is not a self-light emitting device unlike a plasma display panel (PDP) or a cathode ray tube (CRT), the liquid crystal display (TFT-LCD) is a TFT array for transmitting and controlling an electrical signal; It includes a liquid crystal (Liquid Crystal) to determine the transmission of light by varying the molecular structure according to the applied voltage, and a Back Light Unit (BLU) used as a light source on the back along with a color filter.

In the backlight unit, surface light sources such as a cold cathode fluorescent lamp (CCFL) are mainly used. As technology advances, by using a combination of several backlight units together instead of using one large CCFL plate, it is possible to vary the intensity of light supplied from the backlight depending on the location. In other words, the distribution of the video signal within a screen is grasped so that the low brightness video signal is concentrated in the backlight unit corresponding to it, and the high brightness video signal is concentrated in the corresponding backlight unit. By supplying high intensity light, the contrast ratio can be improved. This feature is called local dimming.

In recent years, in order to improve display quality, various methods for outputting a clearer, more realistic, or three-dimensional image have emerged. In order to give an image clarity and a three-dimensional effect, such local dimming is mainly used to increase the contrast ratio through partial luminance increase, and liquid crystal display devices having such a function have been released.

Hereinafter, dimming means of a conventional liquid crystal display will be described in detail with reference to the accompanying drawings.

5 is a conceptual diagram illustrating an image realization principle of a liquid crystal display device employing a local dimming method. The backlight 1 is divided into a plurality of blocks and a light source is provided for each block to individually adjust the illuminance of the light source. When the scaling system is applied to the local dimming method, the light transmittance of the liquid crystal for each block is shown in FIG. 5. Can be maximized and the illuminance of the light source can be lowered, thereby greatly reducing the power loss. When each block corresponds to a plurality of pixels, the light transmittance of the pixel having the largest luminance among the pixels corresponding to the block is maximized, and the light transmittance of the other pixels is adjusted in comparison with the pixel having the maximum luminance. Such a local dimming method can greatly reduce power consumption as described above, and has an advantage of increasing image sharpness. However, in order to adjust the illuminance of the light sources provided in each block, a separate driving circuit must be configured for each block, thereby increasing the manufacturing cost of the liquid crystal display.

In addition, according to another example, a liquid crystal display device in which a plurality of small LEDs are closely arranged has been proposed. When displaying an image such as a bright light on a liquid crystal display, the LED at the point corresponding to the position of the image becomes a high brightness LED, and an LED arranged around the high brightness LED becomes a low brightness LED, and the other LEDs are off LEDs. By being able to give a three-dimensional image to the image.

Using a liquid crystal display device in which a large number of small LEDs are arranged in this way can not only display a smaller image, but also individually operate LEDs located on the left and right sides and top and bottom sides of the image. Since the light emitting part can be represented in more detail, there is an advantage in that the image can be represented more realistically.

However, since a large number of LEDs must be installed, manufacturing cost is high, power consumption is high, and high heat is emitted from each LED. Therefore, a separate heat dissipation structure has to be installed. In addition, the conventional liquid crystal display device has a problem in that an internal configuration is complicated and a lot of circuit components are required because wirings must be separately configured for each LED so as to control each LED independently.

In order to solve the above problems, the present invention can improve image clarity and reduce power loss by applying a local dimming method. It is an object of the present invention to provide a backlight module of a liquid crystal display device, and a liquid crystal display device including the same, which can reduce ice manufacturing.

The backlight module of the present invention for achieving the above object is a dimming panel including a surface light source unit and a plurality of blocks disposed in the light output direction of the surface light source unit, partitioned in a matrix form having a mutually independent space; Each block of the dimming panel includes: an operation electrode for applying power; An electrowetting body injected into the inside of the block with a volume smaller than the volume of the independent space and spread or locally collected on the side of the operation electrode of the block according to the on / off state of the power supply by the electrode; do.

In addition, the backlight module of the present invention includes a dimming control unit for outputting a control signal for controlling the application of power to the operation electrode provided in each block.

In addition, in the backlight module of the present invention, the control signal of the dimming controller is a signal having a constant amplitude, and the dimming is controlled by varying a signal application time to each block.

Further, in the backlight module of the present invention, the control signal of the dimming controller is a pulse signal, and the dimming is controlled by varying the number of pulse signals in each block.

In addition, the electrowetting body in the backlight module of the present invention is characterized in that the color of the black (Color).

In addition, in the backlight module of the present invention, the light source unit includes a light guide plate for guiding the incident light, and a light source installed at one edge of the light guide plate.

Meanwhile, the liquid crystal display of the present invention includes the backlight module as described above.

In the liquid crystal display of the present invention, each of the blocks has a size that corresponds to at least one pixel of the display panel.

As described above, the present invention uses a local dimming method to deliver light individually adjusted to each block of the backlight module to the corresponding pixel, thereby improving the sharpness of the displayed image and reducing power loss.

As the inventive concept allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Terms including ordinal numbers such as first and second may be used to describe various components, but the components are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another.

For example, without departing from the scope of the present invention, the second component may be referred to as the first component, and similarly, the first component may also be referred to as the second component.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, the terms "comprises", "having", and the like are used to specify that a feature, a number, a step, an operation, an element, a component, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Now, a backlight module and a liquid crystal display device employing the same according to an embodiment of the present invention will be described in detail with reference to the drawings. The description may be omitted.

1 is a view schematically showing a liquid crystal display device according to an exemplary embodiment of the present invention, FIG. 2 is a view for explaining the dimming panel of the backlight module shown in FIG. 1 in detail, and FIG. 3 illustrates the operation of the backlight module. 4 is a schematic diagram for illustrating the operation of the electrowetting body according to the embodiment of the present invention.

Referring to FIG. 1, a liquid crystal display includes a display panel 100 and a backlight module 200 including a TFT array substrate 130, a color filter array substrate 110, and a liquid crystal 120 positioned therebetween. It is done by The liquid crystal display adjusts an electric field applied to the TFT array substrate 130 and the color filter array substrate 110 by using the light 240 transmitted from the backlight module 200 to change the inclination of the liquid crystal and thus transmittance of light. By adjusting, the image is realized.

The backlight module 200 improves the brightness ratio of the image displayed by appropriately adjusting the light source 210, the light guide plate 220 for guiding the light emitted by the light source 210, and the light emitted from the light guide plate 220. And a dimming controller 300 for controlling the application of power to the dimming panel 230.

The dimming panel 230 is shown in detail in FIG. 2.

2, the upper plate 235 and the lower plate 236 are provided, and the ground electrode 232 and the operation electrode 233 are provided on the surface facing each other, and each electrode has a water repellent layer 238. It is provided. In addition, a plurality of partitions 234 are provided with a block having an independent space 237 in the form of a matrix, and the block has a lower surface, that is, an operation electrode side surface according to power on / off of the operation electrode 233. An electrowetting body 231 is installed that spreads or collects locally.

The size of the block may be provided in a size corresponding to a pixel of the display panel 100 or in a size corresponding to a plurality of pixels.

 The electrowetting body 231 is provided smaller than the volume of the space 237 of the block. The electrowetting body 231 as described above is implemented as a drop oil, which is used in the dimming of the present embodiment by providing a drop oil of a black series. The black series includes black to close to the black body and gray to controlled contrast. In addition, since the droplet oil is already well known, a detailed description thereof will be omitted.

That is, as shown in FIGS. 3 and 4, in the state where no power is applied to the operation electrode 233, the electrowetting body is widely spread in the block. In this state, since the electrowetting body 231 has a black color, the light emitted from the light guide plate 220 is blocked in the block. When power is applied to the operation electrode 233, the electrowetting body 231 has a shape that is gathered to one side in the block. In this state, the light emitted from the light guide plate 220 is transmitted to the display panel 100 as it is.

The application of power to the operation electrode 233 of the dimming panel 230 is controlled by the output signal of the dimming controller 300. Since the light emitted from the block is controlled by the electrowetting body 231 according to the power on / off of the operation electrode 233, the operation electrode 233 of each block is individually controlled on / off or several It is possible to group blocks of on and off / on control for each group. The dimming control unit 300 may control the application of the operation electrode 233 to the pulse width control method (PWM) or turn on the pulse to control the number of pulses.

On the other hand, the backlight module 200 is an edge type, that is, a method in which the light source 210 is disposed on one side of the light guide plate 220 as an example, but is not limited thereto. The dimming method of the present embodiment can also be applied to the direct type.

One embodiment of the present invention described above should not be construed as limiting the technical spirit of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention as long as it will be apparent to those skilled in the art.

1 is a schematic view of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 2 is a diagram for describing a dimming panel of the backlight module illustrated in FIG. 1 in detail.

3 is a simplified diagram for explaining the operation of the backlight module;

4 is a view for showing the operation of the electrowetting body according to an embodiment of the present invention;

5 is a view for explaining a conventional dimming apparatus

Claims (8)

Surface light source unit, A dimming panel disposed in the light output direction of the surface light source unit, the dimming panel including a plurality of blocks having a mutually independent space partitioned in a matrix form, Each block of the dimming panel, An operation electrode for applying power; An electrowetting body injected into the inside of the block with a volume smaller than the volume of the independent space and spread or locally collected on the side of the operation electrode of the block according to the on / off state of the power supply by the electrode; Backlight module. The method of claim 1, And a dimming control unit for outputting a control signal for controlling the application of power to the operation electrodes provided in the respective blocks. The method of claim 2, The control signal of the dimming controller is a signal of a constant amplitude, A backlight module for controlling dimming by varying the signal application time to each block. The method of claim 2, The control signal of the dimming controller is a pulse signal, A backlight module that controls dimming by varying the number of pulse signals in each block. The method of claim 1, The electro wetting body is a black-based color (Color) backlight module. The method according to any one of claims 2 to 5, The light source unit, A light guide plate for guiding the incident light; And a light source installed at one edge of the light guide plate. A display panel having a plurality of pixels; And a dimming panel including a surface light source unit and a plurality of blocks arranged in the light output direction of the surface light source unit and partitioned in a matrix to have mutually independent spaces. Each block of the dimming panel includes a power source. An operation electrode for applying; An electrowetting body having a volume smaller than that of the independent space is injected into the block and spread or locally gathers on the side of the operation electrode of the block according to the on / off state of the power supply by the electrode. Backlight module; Liquid crystal display comprising a. The method of claim 7, wherein Each block is And a size of a size corresponding to at least one pixel of the display panel.

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