KR101258593B1 - Backlight unit and liquid crystal display module - Google Patents

Abstract

The present invention is directed to a direct type liquid crystal display device using an external electrode fluorescent lamp as a light source, in order to configure a common electrode for applying a voltage collectively to a plurality of external electrode fluorescent lamps having optimal efficiency.

According to the present invention, by forming each corner of the common electrode provided to apply voltage to the external electrode fluorescent lamp in a curved shape, it is possible to prevent the skin effect (skin effect) caused by the conventionally formed corners, the gripper ( By configuring the holder of the gripper as a single plate, it is possible to prevent the proximity effect of intensively flowing high-frequency currents in adjacent portions of the holders adjacent to each other.

Accordingly, a uniform voltage can be applied to each of the plurality of external electrode fluorescent lamps, and energy loss due to the existing deterioration phenomenon can be prevented in advance.

In addition, it maximizes the contact area between the external electrode and the common electrode of the external electrode fluorescent lamp to improve electrical continuity / conductivity, which improves the efficiency of the inverter driving the fluorescent lamp and also improves the efficiency of the fluorescent lamp. have.

Description

Backlight unit and liquid crystal display module

1 is a cross-sectional view of a liquid crystal display device using a general direct type backlight unit.

2 is a view schematically showing the appearance of a common electrode applying a voltage to the external electrode and the external electrode fluorescent lamp of the external electrode fluorescent lamp.

3 is an exploded perspective view schematically showing a liquid crystal display module according to an embodiment of the present invention.

4 is a view schematically showing the appearance of a common electrode applying a voltage to the external electrode and the external electrode fluorescent lamp of the external electrode fluorescent lamp.

FIG. 5 is a view schematically illustrating an external electrode of an external electrode fluorescent lamp and a common electrode applying a voltage to the external electrode fluorescent lamp according to another embodiment of the present invention.

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

121: gripper 123: common electrode

124: external electrode fluorescent lamp 125: stopper

127a, 127b, 127c: holder

128: external electrode

129a and 129b: first and second common electrode lines

B, C, D, E: corner

The present invention is directed to a direct type liquid crystal display device using an external electrode fluorescent lamp as a light source, in order to configure a common electrode for applying a voltage collectively to a plurality of external electrode fluorescent lamps having optimal efficiency.

The image realization principle of a general liquid crystal display device uses the optical anisotropy and polarization property of the liquid crystal. The liquid crystal has a thin and long molecular structure and polarization in which the direction of the molecular array changes according to its size when placed in an electric field and an anisotropy having an orientation in the array. It has a nature. The liquid crystal display is an essential component of a liquid crystal panel composed of a pair of transparent insulating substrates, each having a liquid crystal layer interposed therebetween, and having a field generating electrode formed therebetween. Various images are displayed by artificially adjusting the arrangement direction of the molecules and using the light transmittance which is changed at this time.

Since the liquid crystal panel does not have a light emitting element, a separate light source is required. As a result, a backlight unit having a fluorescent lamp is provided on the rear surface to irradiate light toward the front of the liquid crystal panel, thereby realizing an image of identifiable luminance. The backlight unit is classified into an edge type and a direct type according to its illumination method.

The edge type has a structure in which one or a pair of lamps are disposed on one side of the light guide plate and two or two pairs of lamps on each side of the light guide plate, and the direct type is a structure in which several lamps are disposed below the light guide plate. The edge type has the advantage of being easy to manufacture, while the direct type has a relatively advantageous advantage over a large liquid crystal display in terms of high uniformity of light.

In addition, the fluorescent lamp used for the backlight includes a Cold Cathode Fluorescent Lamp (CCFL) having electrodes at both ends, and an External Electrode Fluorescent Lamp (EEFL) and electrodes at which both electrodes are formed outside the tube. And an electrodeless fluorescent lamp that does not form a light source.

1 is a cross-sectional view of a liquid crystal display using a general direct type backlight unit.

As shown in the figure, a general liquid crystal display module includes a liquid crystal panel 10, a backlight unit 20, a support main body 30, a cover bottom 50, and a top cover 40.

The backlight unit 20 includes a reflective sheet 22 and a plurality of fluorescent lamps 24 arranged on an upper surface thereof, and a plurality of optical sheets 26 interposed therebetween. In this case, the plurality of fluorescent lamps 24 are fixed by a pair of side supports (not shown) fastened to the cover bottom 50.

In addition, the liquid crystal panel 10 is stacked in front of the backlight unit 20, and the backlight unit 20 and the liquid crystal panel 10 are surrounded by the top cover 40 that is bound to the edge of the backlight unit 20 and is coupled to the cover bottom 50. This is fixed integrally.

In addition, a printed circuit board (not shown) is formed at one side of the liquid crystal panel.

In this case, the fluorescent lamp 24 used as the light source of the backlight unit 20 is an external electrode fluorescent lamp having an external electrode formed on the outer surface of both ends of the glass tube. The external electrode fluorescent lamp 24 is a reflective sheet 22. A plurality of electrodes are arranged side by side at a predetermined interval, and a voltage is generated by a common electrode (23 in FIG. 2) which simultaneously connects the external electrodes and applies an external voltage to the plurality of external electrode fluorescent lamps 24 simultaneously. To be authorized.

FIG. 2 is a view schematically illustrating an appearance of a common electrode applying a voltage to an external electrode and an external electrode fluorescent lamp of the external electrode fluorescent lamp.

As shown, the external electrode fluorescent lamp 24 is formed such that the electrode 28 surrounds the outer surface of both ends of the glass tube, and the external electrode fluorescent lamp 24 is in contact with the external electrodes 28 at both ends of the external electrode fluorescent lamp 24. Is applied, and an integrated common electrode 23 for fixing the external electrode fluorescent lamp 24 is configured.

The common electrode 23 is formed in a gripper type, that is, is in direct contact with the external electrodes 28 across the external electrode fluorescent lamp 24, and directly fixes the external electrode fluorescent lamp 24. Holders 27a, 27b, and 27c are formed spaced apart from each other to form a gripper 21.

These grippers 21 are connected to both sides via first and second common electrode lines 29a and 29b. Accordingly, a plurality of grippers 21 are formed at predetermined intervals along the first and second common electrode lines 29a and 29b, and each gripper 21 is provided through holders 27a, 27b and 27c. The external electrode fluorescent lamp 24 is fixed.

In addition, in order to prevent the left and right flow of the external electrode fluorescent lamp 24, a stopper (upper) is formed perpendicular to the end of the second common electrode line (29b) on which the end of the external electrode fluorescent lamp 24 is seated: 25) is configured.

As a result, the external electrode fluorescent lamps 24 arranged in parallel by the common electrode 23 are electrically connected to each other, and the plurality of external electrode fluorescent lamps 24 are driven by one inverter (not shown).

However, the common electrode 23 exhibits some disadvantages. First, as shown in the drawing, all the corners A of the common electrode 23 are formed to be angled. This causes a skin effect in which current flows to the angled corner A portion.

Here, the skin effect is described in more detail. As the frequency of the high frequency current increases, the current is concentrated on the surface of the conductor, and the current is concentrated at the angled corners. The depth at which the current flows is called a skin depth. do.

In other words, if the frequency is low, the charge is carried in the entire area of the conductor, but if the frequency is increased, the induced magnetic force is changed because the increased magnetic field in the middle of the conductor changes to a resistance that prevents the charge. This occurs inside the conductor, reducing the current density at the center of the conductor and increasing the current density at the surface of the conductor.

Therefore, since the corners A of the common electrode 23 are formed to be sharp, the current is concentrated in the corner A portion of the common electrode 23 by the skin effect. As such, when the current is concentrated at a certain place, energy loss may occur due to deterioration of the corner portion A of the common electrode 23 where the current is concentrated, and a plurality of currents are applied through the common electrode 23. Application of a uniform voltage to the external electrode fluorescent lamp 24 becomes difficult.

In addition, the common electrode 23 is affected by the proximity effect by the holders 27a, 27b, and 27c that directly fix the external electrode fluorescent lamp 24. That is, the gripper 21 forms a gripper 21. A plurality of holders (27a, 27b, 27c) are arranged spaced apart from each other by a predetermined interval, so that the high-frequency current flows intensively to the parts close to each other adjacent to each other.

In this case, energy loss may occur due to deterioration due to concentration of current, and uniform current may not be transmitted to the holders 27a, 27b, and 27c.

This proximity effect increases as the current flowing through the common electrode 23 is high frequency, and the holders 27a, 27b, and 27c are disposed closer to each other and separated into several strands.

The present invention is to solve the above problems, the first object is to improve the efficiency by minimizing the energy loss of the common electrode provided for applying a voltage to the external electrode fluorescent lamp.

In addition, the second object is to improve the efficiency of the external electrode fluorescent lamp by minimizing the energy loss of the common electrode.

The present invention to achieve the above object and the first and second common electrode line; A gripper connecting the first and second common electrode lines and configured along a length direction of the first and second common electrodes; A stopper vertically upwardly formed at an outer edge of the second common electrode line, wherein the first and second common electrode lines, the gripper and the stopper have a curved common electrode of the backlight unit in which all corners of the stopper are curved; to provide.

The gripper may include an extension part vertically extending from the first and second common electrode lines, and a plurality of holders configured to be bent upwardly and vertically along a length direction of the extension part. And a holder of a single plate extending vertically from the first and second common electrode lines and vertically bent along the longitudinal direction of the extension.

In this case, the extension unit may connect the first and second common electrode lines to each other, and the stopper may be configured to correspond to the gripper.

In addition, the present invention and the reflection sheet; A plurality of fluorescent lamps arranged side by side on the reflective sheet; A common electrode contacting electrodes on both ends of the plurality of fluorescent lamps to apply a voltage, the common electrode being curved at all corners; A plurality of optical sheets interposed on the plurality of fluorescent lamps; A backlight unit for a liquid crystal display device includes a pair of side supports for fixing and supporting the plurality of fluorescent lamps and a common electrode and forming a gap between the fluorescent lamps and the optical sheet.

The common electrode may include a gripper connecting the first and second common electrode lines, the first and second common electrode lines, and a stopper upwardly perpendicular to an end of the second common electrode line. The gripper may include an extension part vertically extending from the first and second common electrode lines, and a plurality of holders configured to be bent upwardly and vertically along a length direction of the extension part. It features.

The gripper may include an extension part vertically extending from the first and second common electrode lines, and a holder of a single plate configured to be bent vertically along the longitudinal direction of the extension part. An external power source or an inverter connected to one end of the first and second common electrode lines may be further provided.

The plurality of fluorescent lamps may be external electrode fluorescent lamps having electrodes formed on both outer surfaces of glass tubes, and the electrodes of the plurality of fluorescent lamps may be in contact with the gripper and the stopper of the common electrode.

In addition, the present invention is a liquid crystal display module having the above-described backlight unit, the liquid crystal panel mounted on the optical sheet; A support main surrounding the edge of the liquid crystal panel and the backlight unit; A cover bottom adhered to the rear surface of the reflective sheet, and the pair of side supports fixed thereto; The present invention provides a liquid crystal display module including a top cover covering a front edge of the liquid crystal panel.

Hereinafter, the embodiment according to the present invention will be described in detail.

In the present invention, as a method for preventing energy loss due to the skin effect of the common electrode, it is possible to prevent a phenomenon in which current is concentrated in the corner portion of the common electrode by using a conductor having good conductivity.

This is because the skin effect is determined by the frequency and the material, and since the material also varies in resistivity with temperature, the skin depth of the same material is different depending on the temperature. Therefore, the effect of the skin effect is different. do.

The table below shows the penetration depth of the current by the surface depth depending on the temperature of the material.

material Temperature frequency 50 500 1K 3K 10K 400 K iron Room temperature 0.32 0.11 0.08 0.02 0.02 1200 ℃ 6.6 2.3 1.62 0.95 0.52 0.08 s stainless Room temperature 5.7 1.97 1.39 0.8 0.44 0.07 1200 ℃ 7.5 2.6 1.84 1.06 0.58 0.09 copper Room temperature 0.95 0.33 0.23 0.12 0.07 0.01 850 ℃ 1.93 0.66 0.47 0.27 0.15 0.02 aluminum Room temperature 1.07 0.37 0.26 0.14 0.08 0.01 500 ℃ 1.93 0.6 0.47 0.27 0.15 0.02

                                                                    (Unit cm)

Penetration depth (conductivity) according to material and its temperature ............ Table 1

As can be seen from the table, it can be seen that the amount of current flowing through a conductor varies with frequency, and even the same metal varies with temperature.

Here, the depth of penetration can be considered as the conductivity of the conductor. As the depth of penetration increases, charge is carried out over the entire area of the conductor, so that a uniform current flows in the conductor.

Therefore, if the common electrode is configured by adjusting the temperature according to the metal and the penetration depth of the metal as described above, it is possible to prevent the problems caused by the current flow to the surface of the common electrode due to the existing skin effect. Will be.

In addition, the present invention will propose a way to suppress the occurrence of the skin effect by changing the shape of the common electrode in addition to the material change of the common electrode.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings.

3 is an exploded perspective view schematically showing a liquid crystal display module according to an embodiment of the present invention.

As illustrated, the liquid crystal display module includes a liquid crystal panel 110, a backlight unit 120, a support main 130, a cover bottom 150, and a top cover 140.

The backlight unit 120 arranges the reflective sheet 122 and the plurality of external electrode fluorescent lamps 124 side by side on the upper surface thereof, and the plurality of optical sheets 126 on the external electrode fluorescent lamp 124. Configure

In this case, an integrated common electrode 123 for applying a voltage through electrodes across the plurality of external electrode fluorescent lamps 124 is provided, and the plurality of external electrode fluorescent lamps 124 and the common electrode 123 are fixed / A pair of side support 133 is provided to support and is fastened to the cover bottom 150.

In this case, the side support 133 may be interposed on the external electrode fluorescent lamp 124 and the external electrode fluorescent lamp 124 in addition to fixing the common electrode 123 and the external electrode fluorescent lamp 124. The gap between the plurality of optical sheets 126 serves to be constant.

Here, the common electrode 123 is formed of a metal material in the form of a plate, and a plurality of grippers 121 of FIG. 4 are coupled to the electrodes of the respective external electrode fluorescent lamps 124.

Also, the backlight unit 120 and the liquid crystal panel 110 are overlapped by the top cover 140 which overlaps the liquid crystal panel 110 and borders the edge of the backlight unit 120. To be fixed integrally.

At this time, the gate printed circuit board and the source printed circuit board are connected to each other along the edge of the liquid crystal panel 110 by the flexible printed circuit board, and are folded and adhered to the side or the back of the cover bottom 150 during the modularization process. Two adjacent edges of the liquid crystal panel 110 are divided into a gate printed circuit board which scan-transmits the on / off signal of the thin film transistor to a plurality of gate lines and a source printed circuit board which transmits image signals for each frame to a plurality of data lines. Each is provided with.

The above-described configuration is similar to a general liquid crystal display module, but the present invention is particularly effective in that the common electrode 123 applying a voltage to the external electrode fluorescent lamp 124 is not affected by the skin effect or the proximity effect. Characterized in that configured to have. This will be described in more detail with reference to FIG. 4.

FIG. 4 is a view schematically illustrating an appearance of a common electrode applying a voltage to an external electrode and an external electrode fluorescent lamp of the external electrode fluorescent lamp.

As illustrated, the external electrode fluorescent lamp 124 has an electrode 128 surrounding the outer surface of both ends of the glass tube, and an inert discharge gas made of mixed inert gas, mercury (Hg) molecules, or the like inside the glass tube. It is filled with fluorescent material on the inner wall of the glass tube.

The external electrode 128 at both ends of the external electrode fluorescent lamp 124 is contacted to apply a voltage, and an integral common electrode 123 is formed to fix the external electrode fluorescent lamp 124.

At this time, although not shown, a lead wire (not shown) connected to an external power source or an inverter (not shown) is provided at one end of the common electrode 123, and thus the plurality of external electrode fluorescent lamps 124 are provided. Apply the same voltage to each.

The common electrode 123 is formed in a gripper type, and in more detail, the common electrode 123 is in direct contact with the external electrodes 128 at both ends of the external electrode fluorescent lamp 124, and the external electrode fluorescent lamp 124 is provided. Holders 127a, 127b, and 127c for directly fixing them are formed spaced apart from each other to form a gripper 121.

First and second common electrode lines 129a and 129b are formed at both sides of the gripper 121 for connecting the grippers 121.

A plurality of grippers 121 are formed at predetermined intervals along the first and second common electrode lines 129a and 129b, and the grippers 121 have external electrodes through holders 127a, 127b, and 127c. The fluorescent lamp 124 is fixed.

In this case, the structure of the gripper 121 will be described in more detail. The gripper 121 includes an extension part vertically extended to connect the first and second common electrode lines 129a and 129b to each other, and the extension part. It consists of a plurality of holders 127a, 127b, 127c that are bent vertically upward along the longitudinal direction.

The holders 127a, 127b, and 127c are arranged side by side at regular intervals. In this case, a plurality of grippers 121 is configured in proportion to the number of external electrode fluorescent lamps 124.

In addition, in order to prevent the left and right flow of the external electrode fluorescent lamp 124, the stopper 125 is formed perpendicular to the end of the second common electrode line 129b on which the end of the external electrode fluorescent lamp 124 is seated. Is composed.

The external electrode fluorescent lamps 124 arranged in parallel by the common electrode 123 are electrically connected to each other, and the plurality of external electrode fluorescent lamps 124 are driven by one inverter (not shown).

At this time, the gripper 121 including the holders 127a, 127b, and 127c of the common electrode 123, the first and second common electrode lines 129a and 129b connecting the grippers 121, and a stopper ( Each corner (B, C, D, E) of 125) is characterized in that all configured by the curved process.

That is, the first and second common electrode lines 129a and 129b and the gripper 121 are connected to each other through a gripper 121 that vertically connects the first and second common electrode lines 129a and 129b. The corner B is made of a smooth curve.

In addition, the holders 127a, 127b, and 127c of the gripper 121 are bent upwardly and vertically in extension portions extending from the first and second common electrode lines 129a and 129b, thereby forming an edge C and the The corners (D) at which the stoppers are formed perpendicularly to the end of the second common electrode line are bent in a curved shape as well as the edges of the holders (127a, 127b, 127c) and the stopper (125) of the gripper (121). (E) is also formed in a curved line.

As a result, as the frequency of the high frequency current increases, the current is concentrated on the conductor surface, and the skin effect is prevented from flowing through the concentration of the current to the angular corner (A in FIG. 2).

FIG. 5 is a structure for preventing a proximity effect caused by the plurality of holders (127a, 127b, and 127c of FIG. 4 being configured in close proximity to each other as an embodiment of the present invention). FIG. 2 is a view schematically illustrating the common electrode 223 applying a voltage to the external electrode 228 and the external electrode fluorescent lamp 224.

For the same elements performing the same role as in FIG. 4, duplicate description will be omitted.

As shown, the gripper 221 is in direct contact with the external electrodes 228 at both ends of the external electrode fluorescent lamp 224, and is constituted by a holder 227 directly fixing the external electrode fluorescent lamp 224. do.

That is, the holder 227 is formed to surround a part of the external electrode 228 on both ends of the external electrode fluorescent lamp 224, is formed of a single plate, the external electrode 228 of the external electrode fluorescent lamp 224 Maximizes the contact area with and improves electrical continuity / conductivity.

In addition, a plurality of holders (127a, 127b, and 127c of FIG. 4) constituting the conventional gripper 221 are arranged to be spaced apart from each other at a predetermined interval, so that a high frequency current flows intensively in a portion close to each other adjacent to each other. The effect can be prevented beforehand.

In addition, both ends of the external electrode fluorescent lamp 224 and the external electrode 228 are in contact with the stopper 225, so that energy is transmitted by increasing the contact area between the external electrode 228 and the common electrode 223. Make this an optimal state.

As described above, the edges B, C, D, and E of the common electrode 123, which are provided to apply voltage to the external electrode fluorescent lamp 124, are curved to form corners (Fig. It is possible to prevent the epidermal phenomenon caused by A) of 2 in advance.

As a result, a uniform voltage is applied to each of the plurality of external electrode fluorescent lamps 124, and current is concentrated at an angled corner (A of FIG. 2) due to the existing skin phenomenon, thereby preventing energy loss due to deterioration. You can prevent it.

In addition, by configuring the holder (227 of FIG. 5) of the gripper (221 of FIG. 5) as a single plate, a plurality of existing holders (127a, 127b, and 127c of FIG. 4) are arranged to be spaced apart from each other at regular intervals. It is possible to prevent the proximity effect of intensively flowing high-frequency current in adjacent parts of adjacent holders.

In addition, the contact area of the external electrode fluorescent lamp (224 of FIG. 5) with the external electrode (228 of FIG. 5) is maximized to improve electrical continuity / conductivity.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

As described above, the present invention forms a curved shape of each corner of the common electrode provided to apply the voltage to the external electrode fluorescent lamp to prevent the skin phenomenon, thereby providing a uniform voltage to each of the plurality of external electrode fluorescent lamps. There is an effect that is applied, it is possible to prevent the energy loss due to deterioration caused by the current concentrated in the angled corner portion due to the existing skin phenomenon.

In addition, it is possible to prevent the proximity effect in advance by configuring the holder of the gripper in a single plate, and improve the electrical continuity / conductivity by maximizing the contact area with the external electrode of the external electrode fluorescent lamp. have.

This improves the efficiency of the inverter for driving the fluorescent lamp, thereby improving the efficiency of the external electrode fluorescent lamp.

Claims (13)

First and second common electrode lines; Connecting the first and second common electrode lines and extending vertically from the first and second common electrode lines along the length direction of the first and second common electrodes; A gripper composed of a holder configured to be bent upwardly vertically along the gripper; A stopper formed vertically upward at an outer edge of the second common electrode line. And first and second common electrode lines, all edges of the stopper are curved, and the holders face each other in parallel to each other and extend from the extension part, and the first and second surfaces thereof. And first to third side surfaces connecting edges of the second surface, and corners formed by the respective edges of the first to third side surfaces are all curved. The method of claim 1, The holder is a common electrode of the backlight unit, characterized in that a plurality of vertically bent from the extension portion is configured. delete The method of claim 1, And the extension part connects the first and second common electrode lines to each other. The method of claim 1, The stopper may be configured to correspond to the gripper, the common electrode of the backlight unit. A reflective sheet; A plurality of fluorescent lamps arranged side by side on the reflective sheet; A common electrode contacting electrodes on both ends of the plurality of fluorescent lamps to apply a voltage, the common electrode being curved at all corners; A plurality of optical sheets interposed on the plurality of fluorescent lamps; A pair of side supports for fixing and supporting the plurality of fluorescent lamps and common electrodes, forming a gap between the fluorescent lamp and the optical sheet The common electrode includes a gripper including an extension and a holder configured to be bent upwardly and vertically along the longitudinal direction of the extension, wherein the holders face each other in parallel with each other. The first and second sides extending and the first to third side surfaces connecting the edges of the first and second sides, the corners of each of the first to third sides meet each other in a curved line A backlight unit for a liquid crystal display device formed. The method of claim 6, The common electrode includes first and second common electrode lines, the gripper connecting the first and second common electrode lines, and a stopper formed upwardly perpendicular to an end of the second common electrode line. A backlight unit for a liquid crystal display device, characterized in that. The method of claim 6, And a plurality of the holders are bent vertically from the extension part. delete Claim 10 has been abandoned due to the setting registration fee. The method of claim 7, wherein And an external power source or an inverter connected to one end of the first and second common electrode lines. The method of claim 6, And the plurality of fluorescent lamps are external electrode fluorescent lamps having electrodes formed on both exterior surfaces of glass tubes. The method of claim 11, And a plurality of fluorescent lamp electrodes are in contact with the gripper and the stopper of the common electrode. A liquid crystal display module comprising a backlight unit according to claim 6, A liquid crystal panel seated on the optical sheet; A support main surrounding the edge of the liquid crystal panel and the backlight unit; A cover bottom adhered to the rear surface of the reflective sheet and the pair of side supports fixed thereto; Top cover covering the front edge of the liquid crystal panel Liquid crystal display module comprising a.

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