KR20080106870A - Scanning backlight unit - Google Patents

Abstract

A scanning backlight unit is provided to prevent motion blurring phenomenon of a moving picture without changing design of a valance board. A valance board(200) distributes current by the plurality of parallel fluorescent lamps by being connected with the plurality of parallel fluorescent lamp. A plurality of bank parts(203a, 203b, 203c, 203d) turn on/off or dimming the respective block by block lamp. A control unit(201) enables scanning drive by operating on/off or dimming by parallel fluorescent block by controlling the plurality of bank parts by the image information signal.

Description

Scanning backlight unit

The present invention relates to a scanning backlight unit.

More specifically, in a backlight unit including a balance board and a plurality of parallel fluorescent lamps, each of which is divided into a plurality of parallel fluorescent lamps by receiving an integrated power supply to drive the lamps, dimming for each blocked parallel fluorescent lamp. Or it relates to a scanning backlight unit for driving the scanning to be on / off.

Unlike CRTs, PDPs, and FFDs, the display by the LCD itself is non-luminescent, so it cannot be used in the absence of light. The backlight unit is a device for uniformly irradiating the information display surface for the purpose of making it possible to use in a dark place to compensate for this disadvantage.

The backlight unit generally includes a lamp that receives power and emits light, and an optical member that collects, diffuses, and polarizes light of the lamp to uniformly supply the front surface of the liquid crystal panel. It may also include an inverter for controlling the intensity of light by supplying power to the lamp and controlling the tube current. The backlight unit for LCD can be classified into two types according to the position of the lamp. There are two types of backlight units such as a metering type provided on the side of the liquid crystal display and a direct type type provided with a plurality of lamps corresponding to the front surface of the liquid crystal panel. In the direct type, a plurality of lamps are arranged on a plane, and a diffusion plate is installed between the lamp and the liquid crystal panel to maintain a constant between the liquid crystal panel and the lamp. In addition, the metering type is a lamp installed outside the flat plate, the light is incident from the lamp to the entire surface of the liquid crystal panel using a light guide plate. Recently, as a liquid crystal display device having a higher luminance is required in LCD-TV, a direct type backlight unit is mainly used for LCD-TV.

Fluorescent lamps used as a light source in the backlight unit include a cathode fluorescent lamp (CFL) and an external electrode fluorescent lamp (EEFL). Cathode fluorescent lamps include Cold Cathode Fluoresence Lamps (CCFLs) and Hot Cathode Fluoresence Lamps (HCFLs). In the case of large size, CCFL is mainly used (the diameter of CCFL is usually 1.6mm ~ 2.2mm and the life span is about 15,000 ~ 60,000 hours).

The light metering type includes a light guide panel (LGP) that uniformly spreads the light flowing from the lamp to the entire screen, and may be classified into a side type and an edge type according to the shape of the light guide plate. In the case of the direct type method, the light guide plate may be included in the same manner as in the case of the photometric type in the case where a lamp is disposed in a part of the lower part of the liquid crystal panel.

As the optical member used in the backlight unit, generally, the light from the lamp is reflected to the front of the light guide plate by the total reflection of the light guide plate to the front to increase the overall brightness and to prevent the loss of light from the back of the light guide plate. Reflector sheet, diffuser sheet to make the light emitted from the light guide plate more uniform, and soften overall, and to increase the brightness by refracting and condensing the luminance by the diffuser sheet. Prisms (Prism or BEF: Brightness Enhencement Film). The prism sheet has a mountain-shaped fine pitch. The lower part is vertical and the upper part is horizontal, and these two sheets are usually used as a set. In addition, as a frame for assembling the BLU parts such as a lamp reflector, a light guide plate, sheets, and a lamp into one, the mold frame may include a mold frame having a shape maintaining function.

Since the present invention relates to a scanning backlight unit in a backlight unit driven by dividing and distributing a current by a parallel fluorescent lamp supplied with an integrated power source, a direct type backlight unit will be described.

1 is a block diagram of a backlight unit driven by dividing and distributing a current by a parallel fluorescent lamp supplied with an integrated power source from a conventional IP board (Integrated Power Board). For example, in FIG. 1, when 20 lamps (lamps) are required, 6 mA per lamp is required, and in the case of a backlight unit of 20 lamps, a total current I _ttl = 6 × 20 = 120 mA is required, and the IP-board is only 120 mA. If present, the current is distributed equally to 1/20 on the balance board, keeping the current supplied to each lamp constant at 6mA. Such a conventional LCD backlight unit is difficult to implement a scanning function to sequentially change the brightness by dividing the screen partition when using the current balance board when dividing the power output of the IP-board to drive several lamps at the same time. Therefore, when a moving image is implemented by LCD, there is a problem that a moving object such as a motion blurring due to an afterimage of a screen cannot be clearly seen due to the response speed of the liquid crystal.

The present invention has been made to solve the above-described problems, divided the area of the LCD backlight unit, according to the screen image information provided to the LCD panel, the lamp of the backlight unit (On / Off) or weakens the current strength The purpose of the present invention is to provide a scanning backlight unit that easily prevents motion blurring without changing the design of an existing balance board through partial dimming.

In order to solve the above-mentioned problems, in one aspect of the present invention, a backlight unit comprising a balance board and a plurality of parallel fluorescent lamps to drive the lamp by being divided into a plurality of parallel fluorescent lamps supplied with an integrated power supply; The balance board comprises: a plurality of banks each connected to a plurality of parallel fluorescent lamps each blocked to divide and distribute current for each block of the plurality of parallel fluorescent lamps and to dimm or turn on / off the lamps for each of the blocks; bank; And a control unit receiving the image information signal from the LCD driving system and controlling a plurality of bank units according to the image information signal so as to dim or turn on / off each block of the parallel fluorescent lamp to enable scanning driving. Provided is a scanning backlight unit, characterized in that made.

In addition, in one preferred aspect of the present invention, the plurality of parallel fluorescent lamps are uniformly blocked by at least two or more, and the plurality of bank units are sequentially arranged corresponding to the sequential driving directions of the LCD panel under the control of the controller. Dividing and dividing the current into the blocked parallel fluorescent lamps to be dimmed (dimming) or on / off for each block of the parallel fluorescent lamps.

Further, in another preferred aspect of the present invention, the plurality of parallel fluorescent lamps are made of cold cathode fluorescent lamps (CCFL), and in another aspect, the plurality of parallel fluorescent lamps are external electrode fluorescent lamps (EEFL). It can be made of).

As described above, the scanning backlight unit according to an aspect of the present invention, when a moving image is implemented in LCD, etc., moving objects such as motion blurring due to an afterimage of the screen due to the response speed of the liquid crystal cannot be clearly seen. In order to solve the problem that the phenomenon occurs, by providing a scanning backlight unit that can be dimmed (dimmed) or off (divided) partially by dividing the area of the LCD backlight unit, without changing the design of the existing balance board There is an effect that can easily solve the motion blur (Motion Blurring).

Hereinafter, embodiments of the present invention for achieving the above object are described with reference to the accompanying drawings. In describing the present embodiments, redundant additional descriptions may be omitted below.

Hereinafter, a scanning backlight unit according to an exemplary embodiment of the present invention will be described in more detail with reference to FIG. 2.

2 is a block diagram of a scanning backlight unit according to an exemplary embodiment of the present invention.

Referring to Figure 2 in detail with reference to the configuration according to an embodiment of the present invention, the scanning backlight unit comprises a plurality of fluorescent lamp 300 and the balance board 200.

The integrated power supply unit 100 shown in FIG. 2 is an inverter (Inverter) and power supply that converts the DC current input to an alternating current, such as an IP board (Integrated Power Board) or LIPS (LCD Inverter Power Supply) board to provide a lamp It may be an integrated power supply including an apparatus or an integrated inverter in which current is supplied to a plurality of parallel fluorescent lamps by one inverter. In a broad sense, the backlight unit may be referred to as an inverter or the like. Power supply used for IP board is SMPS (Switching Mode Power Supply). In other words, the IP board is an integrated power supply that converts the DC power supplied to the power supply from an inverter to an alternating current and provides it to the lamp. The LIPS board also integrates an inverter and a power supply, and is an integrated power supply that is substantially the same as an IP board. Even if the power supply and the inverter are not integrated, it is obvious that the integrated inverter supplying the integrated power to the balance board 200 may also be the integrated power supply 100.

As shown in FIG. 2, the plurality of parallel fluorescent lamps 300 forming a part of the scanning backlight unit constitute a light source of the backlight unit, and the lamp 300 includes a cathode fluorescent lamp (CFL) and an external electrode fluorescent lamp ( External Electrode Flourscent Lamp, EEFL) may be used. Cathode fluorescent lamps include Cold Cathode Fluoresence Lamps (CCFLs) and Hot Cathode Fluoresence Lamps (HCFLs). have. It is obvious that EEFL or HCFL can be used.

As shown in FIG. 2, the plurality of parallel fluorescent lamps 300 are divided into blocks 301, 303, 305, and 307 so as to correspond to the plurality of banks 203a, 203b, 203c, and 203d, respectively. The blocked lamps receive current from the plurality of bank units 203a, 203b, 203c, and 203d, respectively, to form a light source. Blocked lamps may be partitioned and partitioned evenly by at least two or more.

The balance board 200 receives the output power from the integrated power supply unit 100 and divides and distributes the plurality of lamps 300 to the plurality of lamps 300 to drive the plurality of lamps 300. As described above, the control unit 201 and the bank units 203a, 203b, 203c, and 203d are included.

The control unit 201 receives an image information signal from the LCD driving system by the signal connection line 400. Preferably, the image information signal includes end and / or start information of a unit frame as frame information. Blocked parallel fluorescent lamps corresponding to the sequential driving direction of the LCD panel according to the end information of the unit frame which are sequentially provided to the LCD panel sequentially control off or weakly the current intensity, thereby reducing the screen image signal and The plurality of bank units 203a, 203b, 203c, and 203d are controlled to drive scanning in association with each other.

The bank units 203a, 203b, 203c, and 203d may include one or more blocked lamps 301, 303, and 305 connected to the bank units 203a, 203b, 203c, and 203d by the control of the controller 201. 307 to distribute the current selectively. Each of the blocked lamps connected to each of the banks 203a, 203b, 203c, and 203d is dimmed and / or turned on / off under the control of the controller 201.

Of course, the configuration as described above is not limited to this configuration for one embodiment, it is obvious that it can be changed in various forms by those skilled in the art.

Hereinafter, the operation principle of the scanning backlight unit according to an embodiment of the present invention as described above with reference to FIG. 2 will be described in more detail.

Since the backlight unit in the present invention receives the integrated power and divides and distributes the light into a plurality of parallel fluorescent lamps to drive the lamp, first, an integrated driving power supply from an integrated power supply for an LCD TV or an LCD monitor, for example, an IP board or an integrated inverter. This is applied to the Balance board. The balance board 200 includes the controller 201 and the bank units 203a, 203b, 203c, and 203d. Conventionally, it is difficult to drive the scan by performing a function of distributing current power to each parallel-connected lamp in the balance board receiving the integrated supply power, but as in the embodiment of the present invention, the control board (200) 201 and a plurality of banks 203a to 203d corresponding to the blocked lamps, and the fluorescent lamps 301 and 303 blocked by the plurality of banks 203a to 203d under the control of the control unit 201. The scanning function is performed by turning on / off or dimming 305 and 307.

In detail, the control unit 201 receives a screen image signal from the LCD driving system through the signal connection line 400. The screen image signal is shown as a control signal in FIG. 2. The screen image signal or the image information signal is image frame information and includes end and / or start information of a unit frame.

 In LCD panels, data signals constituting pixels are sequentially provided at a high speed, for example, at a 120 Hz frame frequency. In this case, when data is sequentially transmitted from one video frame to the next video frame due to the delay of the response speed of the liquid crystal, the data of the previous video frame remains while the data of the next video frame is provided. Will be displayed. Especially in the case of video, such afterimages are visually recognized. Therefore, when data transmission of one image frame is completed, the completed information is transmitted to the control unit 201 to turn off the light source of the backlight unit corresponding to the pixel region where the image frame transmission is completed or to decrease the current intensity. By lowering the luminance, the visual afterimage effect can be reduced.

That is, the control unit 201 receives the end information of the unit image frame from the image information signal and time-synchronizes with the received image information signal to timely transmit the unit image frame data. Corresponding bank portions 203a, 203b, 203c and 203d are controlled to turn off or dimm the blocked fluorescent lamps 301, 303, 305 or 307. The corresponding bank unit is controlled to turn on the blocked fluorescent lamp which is temporarily turned off by receiving the start information of the next unit image frame from the image information signal and time synchronization with the received image information signal. In other words, according to the end / start information of the unit frame which is sequentially provided to the LCD panel, the blocked parallel fluorescent lamps corresponding to the sequential driving direction of the LCD panel are sequentially turned off or turned on or off. By controlling the intensity, scanning driving is linked with the screen image signal. The controller 201 controls the bank unit to be sequentially turned on / off or the intensity of the current is sequentially adjusted for each blocked lamp corresponding to an area sequentially provided on the LCD panel.

The bank units 203a, 203b, 203c, and 203d are electrically connected to the control unit 201 and turned on / off under the control of the control unit 201 according to the image information signal or the screen image information received from the control unit 201. The fluorescent lamps 301, 303, 305, and 307 are turned on or off by selectively supplying current to the fluorescent lamps 301, 303, 305, and 307 that are blocked on and off, respectively, or dimming. Control as possible.

Accordingly, the balance board 200 selectively distributes current to the blocked fluorescent lamp 300 of the backlight unit according to the screen image information received from the LCD driving system to project the backlight onto the LCD panel, thereby scanning according to the screen image. ) Enable driving to remove the afterimage on the screen.

The scanning driving refers to visually and artificially removing the afterimage of the moving image of the LCD panel by quickly turning on / off the lamp 300 of the backlight unit or adjusting the current intensity.

In the above, the present invention has been described in detail with reference to the accompanying drawings and embodiments, the accompanying drawings and the above embodiments are described by way of example to help those of ordinary skill in the art to understand the present invention. It is. Accordingly, the above embodiments are to be considered as illustrative and not restrictive, and the scope of the invention should be construed in accordance with the invention set forth in the appended claims, the scope of which is to be understood by those of ordinary skill in the art. It includes various changes, alternatives, and equivalents by the person who possesses it.

1 is a block diagram of a backlight unit driven by dividing and distributing integrated power supplied from a conventional IP board into parallel fluorescent lamps.

2 is a block diagram of a scanning backlight unit according to an embodiment of the present invention.

*** Explanation of symbols for the main part of the drawing ***

100: integrated power supply 200: balance board

201: control unit 203a, 203b, 203c, 203d: bank unit

300: fluorescent lamp 400: signal connection line

Claims (4)

A backlight unit comprising a balance board and a plurality of parallel fluorescent lamps for driving a lamp by being divided into a plurality of parallel fluorescent lamps supplied with an integrated power source, The balance board is: A plurality of bank units connected to the plurality of parallel fluorescent lamps each blocked to divide and distribute currents for each block of the plurality of parallel fluorescent lamps and to dimm or turn on / off the lamps for each of the blocks; ; And A control unit configured to receive an image information signal from an LCD driving system and to control the plurality of bank units according to the image information signal to enable dimming or on / off of each block of a parallel fluorescent lamp to enable scanning driving; Scanning backlight unit, characterized in that made. The method of claim 1, The plurality of parallel fluorescent lamps are uniformly blocked by at least two, The plurality of banks divide and distribute current into the blocked parallel fluorescent lamps sequentially according to the sequential driving direction of the LCD panel under the control of the controller to dimm or turn on / off the respective blocks of the parallel fluorescent lamps. Scanning backlight unit, characterized in that to be off. The method according to claim 1 or 2, The plurality of parallel fluorescent lamps are cold cathode fluorescent lamps (CCFL) scanning backlight unit, characterized in that. The method according to claim 1 or 2, The plurality of parallel fluorescent lamps are external electrode fluorescent lamps (EEFL) scanning backlight unit, characterized in that.

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