KR20080069743A - Transformer, back-light unit and liquid crystal display having it - Google Patents

Abstract

A transformer, a back-light unit and a liquid crystal display having the same are provided to reduce noise and protect a bobbin against external impact by forming a protrusion unit with rigid material having high surface density. A transformer includes at least one bobbin unit, a cap(20), and at least one core unit. At least one bobbin unit has a hollow body wound by a coil and is inserted into the cap. The cap includes a plurality of protrusion units(25) to the bobbin unit. At least one core unit is inserted into a hollow of the bobbin unit through both sides of the cap. The protrusion units are made of flexible material, include an infinitesimal protrusion unit, is integrated into the cap, and is formed through an etching or scratch process.

Description

Transformer, backlight unit and liquid crystal display device having the same {Transformer, back-light unit and liquid crystal display having it}

1 is an exploded perspective view of a backlight unit and a liquid crystal display device having a transformer according to an embodiment of the present invention;

2 is an exploded perspective view showing a transformer according to an embodiment of the present invention;

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

4 is an enlarged view of a portion B of FIG. 3.

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

10a, 10b ... core, 20 ... bobbin cap,

30 ... bobbins, 700 ... transformers,

2000 ... backlight unit.

The present invention relates to a transformer, a backlight unit having the same, and a liquid crystal display device, and more particularly, to a transformer having a noise reduction structure, a backlight unit having the same, and a liquid crystal display device.

In general, a liquid crystal display (LCD), which is one of flat panel displays, has better visibility than a cathode ray tube (CRT), and is smaller than the CRT of a screen size having the same average power consumption, and also generates less heat. As a result, plasma display panels (PDPs) and field emission displays (FEDs) have recently been in the spotlight as the next generation display devices of mobile phones, computers, monitors and televisions.

The liquid crystal display device injects a liquid crystal material, which is an intermediate between solid and liquid, between two surface-treated thin substrates to change the arrangement of liquid crystal molecules by the voltage difference between the electrodes on the upper and lower substrates, thereby generating an image. The liquid crystal display device requires a light source such as a lamp in order to visually recognize the display contents because the panel on which the image is displayed does not emit light by itself.

Typically, for displaying the screen of a large liquid crystal display, a back-light unit is provided for supplying light from its rear surface.

The backlight unit is provided with a cold cathode fluorescent lamp (CCFL) as a light source, and a structure using a transformer is widely used to drive the cold cathode fluorescent lamp.

However, when driving the liquid crystal display, not only mechanical noise but also electromagnetic noise are generated. In particular, noise in a transformer for driving a cold cathode fluorescent lamp occupies the largest part.

Conventionally, a circuit and mechanical improvement method has been proposed to reduce the noise of such a transformer. However, despite such conventional techniques, efficient noise reduction has not been achieved. .

The present invention has been made to solve the conventional problems as described above, a transformer, a backlight unit having the same to efficiently attenuate the noise with only a simple structural change while maintaining the mechanical and circuit structure as possible and It is an object to provide a liquid crystal display device.

In order to achieve the above object, the transformer according to the present invention, at least one bobbin portion having a hollow body wound around the coil, the bobbin portion is inserted, both sides of the cap and the cap is formed with a plurality of protrusions toward the bobbin portion At least one core portion penetrated and inserted into the hollow of the bobbin portion.

Here, the plurality of protrusions may be made of a soft material such as at least one or more selected from the group consisting of glass fiber, rock wool, felt, cork and soft fiber plate, the plurality of protrusions are porous, or at least two or more members May be arranged in a vacuum to each other.

Furthermore, a plurality of protrusions may be further formed with minute protrusions.

At this time, the plurality of protrusions is preferably configured integrally with the cap, it may be formed by an etching or scratch process.

The backlight unit according to the present invention includes at least one transformer which supplies power to at least one light source and at least one light source and has a cap having a plurality of protrusions.

The liquid crystal display according to the present invention includes a backlight unit including at least one or more transformers having a cap having a plurality of protrusions, and a liquid crystal display panel displaying an image using light supplied from the backlight unit.

Hereinafter, a preferred embodiment of a transformer, a backlight unit having the same, and a liquid crystal display according to the present invention will be described in detail with the accompanying drawings.

1 is an exploded perspective view of a backlight unit and a liquid crystal display including a transformer according to an exemplary embodiment of the present invention.

Referring to FIG. 1, a liquid crystal display device having a transformer 700 according to the present invention includes a display assembly 1000 disposed above and a backlight unit 2000 disposed below.

The display assembly 1000 includes a liquid crystal display panel 100, driving circuits 200 (210, 230), and an upper accommodating member 250.

The liquid crystal display panel 100 includes a color filter substrate 110 and a thin firm transistor (TFT) substrate 120. In this case, the color filter substrate 110 is a substrate in which RGB pixels, which are color pixels in which predetermined colors are expressed while light passes, are formed by a thin film process. The front surface of the color filter substrate 110 is coated with a common electrode made of a transparent conductor such as indium tin oxide (ITO) or indium zinc oxide (IZO).

The TFT substrate 120 is a transparent glass substrate on which TFTs in matrix form are formed. The data line is connected to the source terminal of the TFTs, and the gate line is connected to the gate terminal. In addition, a pixel electrode made of a transparent electrode made of a transparent conductive material is formed in the drain terminal. When an electrical signal is input to the data line and the gate line, each TFT is turned on or turned off to apply an electrical signal necessary for pixel formation of the drain terminal. When the TFT is turned on by applying power to the gate terminal and the source terminal of the TFT substrate 120, an electric field is formed between the pixel electrode and the common electrode of the color filter substrate 110, thereby forming the TFT substrate 120 and the color. The arrangement of the liquid crystals injected between the filter substrates 110 is changed, and the light transmittance is changed according to the changed arrangement to obtain a desired image.

The driving circuit unit 200 connected to the liquid crystal display panel 100 includes a data side printed circuit board 210b for mounting a control IC and applying a predetermined data signal to a data line of the TFT substrate 120. And a gate-side printed circuit board 230b for mounting a control IC and applying a predetermined gate signal to a gate line of the TFT substrate 120, and a TFT substrate 120 and a data-side printed circuit board having an exposed ground pattern. Data-side flexible printed circuit board 210a for connecting between 210b and gate-side flexible printed circuit board for connecting between TFT substrate 120 and gate-side printed circuit board 210b with an exposed ground pattern. 230a.

The data side and gate side printed circuit boards 210b and 230b are connected to the data side and gate side flexible printed circuit boards 210a and 230a to apply external image signals and gate driving signals. The data side and gate side printed circuit boards 210b and 230b may be integrated into one printed circuit board and connected to one side of the liquid crystal display panel 100. Of course, for this purpose, the data line and the gate line of the TFT substrate 120 may be exposed to one side.

The data side and gate side flexible printed circuit boards 210a and 230a are respectively connected to the data line and the gate line of the TFT substrate 120 to apply the data driving signal and the gate driving signal to the thin film transistor. In addition, a flexible printed circuit board (210a, 230a) is equipped with a tap (TAB) IC, RGB (Read, Green, Blue) signal, SSC (Shift Start Clock) signal, LP (Latch Pulse) generated from the printed circuit board ) Signal, a gamma analog ground signal, a digital ground signal, a digital power supply, an analog power supply common voltage, and a storage voltage are transmitted to the liquid crystal display panel 100. Of course, an IC may be mounted on the TFT substrate 120.

The upper accommodating member 250 is bent at a right angle to protect the liquid crystal display panel 100 or the backlight unit 2000 that are fragile by an externally applied shock while preventing components of the display assembly 1000 from being separated. It is manufactured in the form of a square frame having a flat portion and a side wall portion.

The backlight unit 2000 may include a lamp unit 300 for generating light, a reflector plate 400 disposed under the lamp unit 300, a plurality of optical plates 500 disposed on the lamp unit 300, A lower accommodating member 600 for accommodating the reflective plate 400, the lamp unit 300, and the optical plate 500, and a socket board disposed on the rear surface of the lower accommodating member 600 and connected to the lamp unit 300. 800, and a transformer 700 for converting the magnitude of the AC power supplied from the inverter not shown. In this case, the socket board 800 is electrically connected to the transformer 700.

Here, the lamp unit 300 includes a plurality of rod-shaped lamps 310 arranged in parallel, a plurality of lamp fixing parts 320 for fixing the lamp 310, and a plurality of lamp fixing parts 320 are accommodated. Lamp support 330 is included. The lamp 310 generates light by a power source applied from the outside. Here, the lamp fixing part 320 corresponding to the single electrode is connected to the socket board 800. In this case, the lamp support 330 is formed of an insulating material to electrically insulate the electrode of the lamp 310 and the lower housing member 600.

The plurality of lamps 310 mainly use cold cathode fluorescent lamps, and each lamp 310 includes a glass tube, inert gases included in the glass tube, and a negative electrode and a positive electrode installed at both ends of the glass tube. At this time, the phosphor is coated on the inner wall of the glass tube. The lamps 310 are preferably arranged at equal intervals for luminance uniformity, and the number of lamps 310 is preferably determined according to the required luminance. Each of the lamp fixing parts 320 includes a base substrate on which one end of the lamp is mounted, and a fixing clip and a fixing protrusion for protruding from the base substrate to fix the lamp. The lamp support 330 includes a bottom surface on which the plurality of lamp fixing parts 320 are mounted and a sidewall extending vertically from the bottom surface.

As the reflective plate 400, a plate having a high light reflectance is used to reflect light emitted from the lower portion of the lamp unit 300 to the optical sheet 500 to reduce light loss. The reflective plate 400 is installed to contact the bottom surface of the lower accommodating member 600. Although the reflective plate 400 is illustrated as having a flat shape in the drawing, the reflective plate 400 may be manufactured in a curved shape having a reference reflective surface and a triangular protrusion protruding from the reference reflective surface. In addition, the reflective plate 400 may be omitted by forming a material having excellent reflection efficiency on the bottom surface of the lower accommodating member 600, or the lower accommodating member 600 and the reflective plate 400 may be integrally formed.

The plurality of optical sheets 500 include a diffusion sheet and a prism sheet, which are disposed above the lamp unit 300 to uniform the luminance distribution of the emitted light. The diffusion sheet directs the light incident from the lamp unit 300 toward the front of the liquid crystal display panel 100, and diffuses the light to have a uniform distribution in a wide range so that the liquid crystal display panel 100 is irradiated. As the diffusion sheet, it is preferable to use a film composed of a transparent resin coated with a predetermined light diffusion member on both surfaces. The prism sheet serves to change the light incident obliquely among the light incident on the prism sheet to be emitted vertically. This is because the light efficiency increases when the light incident on the liquid crystal display panel 100 is perpendicular to the liquid crystal display panel 100. Therefore, at least one prism sheet may be disposed under the liquid crystal display panel 100 to vertically convert the light emitted from the diffusion sheet. In this embodiment, two prism sheets are used, and a first prism sheet for polarizing light in one direction and a second prism sheet for polarizing light in a direction perpendicular to the first prism sheet.

The lower accommodating member 600 is formed in a box shape of a rectangular parallelepiped in which an upper surface is opened, and an accommodating space having a predetermined depth is formed therein. The lower accommodating member 600 includes a bottom surface and sidewalls extending vertically from each edge from the bottom surface.

The socket board 800 is a board for applying power to the lamp unit 300. The socket board 800 is disposed on the bottom of the lower accommodating member 600 and is connected to the lamp unit 300 by wires (not shown).

Transformer 700 is for supplying the socket board 800 by changing the size of the power to fit the lamp unit 300 receives the power converted into alternating current from an inductor (not shown), the inductor (not shown) The magnitude of the power is changed to apply the converted and applied power to the plurality of lamps 310. At this time, the transformer 700 adjusts the size of the power to be output to the internal coil.

2 is an exploded perspective view showing a transformer according to an embodiment of the present invention.

As shown in FIG. 2, in the transformer 700 according to the embodiment of the present invention, at least one bobbin portion 30 and a bobbin portion 30 having a hollow body in which a coil is wound are inserted, At least one core portion inserted into the hollow 51 of the bobbin portion 30 through the bobbin cap 20 and the both sides of the bobbin cap 20, the plurality of protrusions 25 are formed toward the hollow portion 30 ( 10a, 10b).

The cores 10a and 10b are composed of a first side portion 10a and a second side portion 10b having an approximately 'E' shape. The cores 10a and 10b pass through the core through-holes 21 to be described later of the bobbin cap 20 and are inserted into the core inserting portions 51 to be described later of the bobbin 30.

The bobbin 30 may include a winding part 40 having at least one coil winding point and a bobbin jaw portion. The winding part 40 has a hollow shape in which a core inserting part 51 through which the cores 10a and 10b are inserted is formed.

The primary coil winding point of the winding portion 40 is formed with a plurality of slots for winding the primary coil to which the DC power from the PFC rectifier (not shown) is applied, and each slot is partitioned by a partition wall portion. . The barrier rib portion is provided with a fixing groove for fixing the lead wire and / or the lead wire of the primary coil. Accordingly, when the primary coil is wound around the winding unit 40, the lead wire and / or the lead wire of the primary coil may be stably fixed.

In addition, a plurality of slots for winding the secondary coil connected to the lamp 310 is formed at the secondary coil winding point of the winding unit 40, and the secondary coil is formed by the winding ratio between the primary coil and the secondary coil. Induced high voltage direct current power flows. At this time, the slot of the secondary coil winding point is also partitioned by the partition wall.

On the other hand, the bobbin 30 includes a first support plate portion 52 integrally formed at the coil winding point side end, and a second support plate portion 55 integrally formed at the other end thereof.

The first support plate part 52 supports the first connection pins 53 to which the lead wires and the lead wires of the primary coils are respectively connected. In addition, a first guide groove (not shown) in which the lead wire and the lead wire of the primary coil are inserted between the primary coil winding point and the first connection pin 53 is provided on the lower surface of the first support plate 52. Accordingly, the lead wire and the lead wire of the primary coil may be inserted into the first guide groove to be stably fixed between the primary coil winding point and the first connecting pin 53.

The second support plate part 55 supports the second connection pins 56 to which the lead wires and the lead wires of the secondary coils are respectively connected. In addition, a second guide groove (not shown) is provided on a lower surface of the second support plate part 55 to insert the lead wire and the lead wire of the secondary coil between the winding part 40 and the second connecting pin 56. Lead wires and lead wires of the secondary coil are inserted into the second guide grooves so as to be stably fixed between the winding part 40 and the second connection pin 56.

Meanwhile, the bobbin cap 20 has a receiving space in which the bobbin 30 is accommodated, corresponding to the shape of the bobbin 30. The core through-holes 21 through which the cores 10a and 10b penetrate are formed at both sides of the bobbin cap 20 so that the cores 10a and 10b are inserted into the core inserting portions 51 of the bobbin 30.

Here, a coupling rib (not shown) protruding toward the bobbin 30 may be provided inside the bobbin cap 20.

3 is a cross-sectional view taken along the line AA ′ of FIG. 2, and FIG. 4 is an enlarged view of a portion B of FIG. 3.

The bobbin cap 20 has a plurality of protrusions 25 facing the bobbin 30 inserted therein, as shown in FIG. The protrusion 25 is to reduce the noise of the transformer 700, but may be configured to be attached to the inner surface of the bobbin cap 20, it is preferably formed integrally with the bobbin cap 20.

When integrally formed with the bobbin cap 20, the protrusion 25 may be formed by an etching process, a scratch process, or the like.

In the case of a detachable form attached to the bobbin cap 20, the protrusion 25 is made of a soft material such as glass fiber, rock wool, felt, cork, soft fiber board, etc., and is referred to as felt, so-called "Velcro®". It can include loops, small pieces of fiberglass, cotton or all bets from hook-loop fasteners that are to be made.

The protrusion 25 may be manufactured in a form in which a plurality of members are arranged in a vacuum to each other, such as a so-called dewar bottle structure. In this case, since a plurality of interfaces exist in the acoustic path from the bobbin 20 to the outside and must pass through the path in which the vacuum is formed, the noise attenuation ability may be further improved.

In general, in order to attenuate the noise generated by the transformer 700 itself, it is preferable that the acoustic transmission loss TL defined by Equation 1 is large.

(Equation 1)

TL = L ₁ -L ₂ + 10 log 10 (S / A)

Here, L ₁ is the average sound pressure level (dB) of the sound source, L ₂ is the average sound pressure level (dB) of the sound receiver, A is the total sound absorption area of the sound receiver, and S is the total surface area of the sound receiver.

As shown in Equation 1, it is preferable to increase the total sound absorption area at the sound receiver in order to increase the acoustic transmission loss value.

Therefore, in the present invention, as shown in FIG. 4, the minute protrusions 26 may be further formed on the individual protrusions 25, or the protrusions 25 may be made porous to increase the sound absorption area.

In the noise attenuation, in particular, the noise in the low frequency region is governed by the transmission loss due to the stiffness of the shielding material, and is determined by the damping of the shielding material near the resonance frequency of the shielding material. At frequencies above the resonant frequency, the acoustic transmission loss is determined by the mass of the shield.

For example, as the frequency or the surface density of the shielding material is doubled, the acoustic transmission loss increases by 6 dB, as shown in Equation 2 below.

(Equation 2)

TL = 20 logρ + 20 logf-c (dB)

Where f is frequency, ρ is the surface density of the shield, and c is a constant depending on the shape of the incident wave.

As in Equation 2, when the frequency is constant, the higher the surface density, the higher the acoustic transmission loss.

Therefore, the protruding portion 25 may also be formed of a rigid material having a high surface density, and the greater the specific gravity and the better the air barrier property, the greater the damping effect.

When the protrusion 25 is integrally formed with the bobbin cap 20 to form a rigid material having a high surface density, the noise attenuation ability can be improved and the internal element, that is, the bobbin 30 can be protected from external impact. Ability can be improved.

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

As described above, the transformer according to the present invention, the backlight unit and the liquid crystal display device having the same, it is possible to efficiently attenuate the noise by only a simple structural change while maintaining the mechanical and circuit structure to the maximum.

Claims (10)

At least one bobbin portion having a hollow body in which a coil is wound; A cap in which the bobbin part is inserted and a plurality of protrusions are formed toward the bobbin part; And At least one core portion penetrating both sides of the cap and inserted into the hollow of the bobbin portion; Transformer comprising a. The transformer of claim 1, wherein the plurality of protrusions are made of a flexible material. The transformer of claim 2, wherein the soft material is at least one selected from the group consisting of glass fiber, rock wool, felt, cork, and soft fiber board. The transformer of claim 1, wherein the plurality of protrusions are porous. The transformer according to claim 1, wherein at least two or more of the plurality of protrusions are arranged in vacuum to each other. The transformer of claim 1, wherein each of the plurality of protrusions further includes a minute protrusion. The transformer of claim 1, wherein the plurality of protrusions are integrally formed with the cap. 8. The transformer of claim 7, wherein the plurality of protrusions are formed by an etching or scratching process. At least one light source; And At least one transformer for supplying power to the at least one light source and having a cap having a plurality of protrusions; A backlight unit comprising a. A backlight unit including at least one transformer having a cap having a plurality of protrusions; And A liquid crystal display panel displaying an image using light supplied from the backlight unit; Liquid crystal display comprising a.

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