KR101002310B1 - Fluorescent lamp and backlight unit by using the same - Google Patents

Abstract

The present invention is to provide a light emitting lamp that can lower the tube voltage, the partial luminance control and a backlight unit using the same, the light emitting lamp for achieving the above object is a tube (tube) defined by divided into N region; And a plurality of external electrodes formed at both ends of the tube and at the boundary portions of the respective divided regions.

In addition, the backlight unit according to the present invention includes a tube divided into N regions and first to (N + 1) external electrodes formed at both ends of the tube and at boundary portions of the respective divided regions. A plurality of light emitting lamps configured; The plurality of first to (N + 1) common electrodes configured to bundle the light emitting lamps in a predetermined unit so that the first to (N + 1) external electrodes of the light emitting lamps of each unit are commonly connected to each other. It is characterized by including.

Light emitting lamp, external electrode, common electrode, inverter

Description

Light emitting lamp and backlight unit using same {FLUORESCENT LAMP AND BACKLIGHT UNIT BY USING THE SAME}

1 is a schematic structural diagram of a conventional edge type backlight unit

2 is a schematic structural diagram of a conventional direct type backlight unit

3 is a structural diagram of a light emitting lamp according to an embodiment of the present invention;

4A and 4B are diagrams illustrating a connection structure of the light emitting lamp and the inverter of FIG. 3 and a tube voltage waveform diagram applied to each external electrode of the light emitting lamp.

5 is a top plan view of a backlight unit according to a first embodiment of the present invention;

6 is a top plan view of a backlight unit according to a second embodiment of the present invention;

Explanation of symbols on the main parts of the drawings

30, 50, 60: light emitting lamps 31a, 51a, 61a: first external electrode

31b, 51b, 61b: second external electrode 31c, 51c, 61c: third external electrode

31d, 51d, and 61d: fourth external electrode 40: inverter

50a, 60a: tube 52a, 62a: first common electrode

52b, 62b: second common electrode 52c, 62c: third common electrode

52d, 62d: fourth common electrode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, and more particularly, to a light emitting lamp capable of lowering a tube voltage and adjusting partial luminance, and a backlight unit using the same.

CRT (Cathode Ray Tube), one of the commonly used display devices, is mainly used for monitors such as TVs, measuring devices, and information terminal devices.However, due to the weight and size of the CRT itself, Could not respond actively to demands.

Therefore, in the trend of miniaturization and weight reduction of various electronic products, CRT has a certain limit in weight and size, and is expected to replace the liquid crystal display device (LCD) using the electro-optic effect, and gas discharge. There are plasma display panels (PDPs) and electroluminescent displays (ELDs) using electroluminescent effects, among which researches on liquid crystal displays (LCDs) are being actively conducted.

In order to replace the CRT, liquid crystal display devices having advantages such as small size, light weight, and low power consumption have been actively developed. In recent years, an ultra-thin flat display display having a thickness of only a few centimeters (Cm) is used. Developed enough to fulfill its role as a device, it is used in spacecraft, aircraft, laptop computers, laptop computer monitors, desktop computer monitors, and large information display devices. The demand for liquid crystal display devices continues to increase. to be.                         

Since most of the liquid crystal display devices are light-receiving devices that display images by controlling the amount of light coming from the outside, a separate light source, that is, a backlight unit, for irradiating light to the LCD panel is necessary.

In general, a backlight unit used as a light source of a liquid crystal display device is classified into an edge method and a direct method according to a method of arranging a cylindrical light emitting lamp.

First, the edge method is that the lamp unit is installed on the side of the light guide plate for guiding the light, the lamp unit is a lamp that emits light, the lamp holder which is inserted at both ends of the lamp to protect the lamp and the outer peripheral surface of the lamp and one side It is provided with a lamp reflection plate fitted to the side of the light guide plate to reflect the light emitted from the lamp toward the light guide plate.

The edge method in which the lamp unit is installed on the side of the light guide plate is applied to a relatively small liquid crystal display device such as a monitor of a laptop computer and a desktop computer, and has good light uniformity and a long durability life. It is advantageous to thin the liquid crystal display device.

On the other hand, the direct method began to be developed mainly as the size of the liquid crystal display device became larger than 20 inches, and arranged a plurality of lamps in a row on the lower surface of the diffuser plate to direct light directly to the front of the LCD panel. will be.

The direct method is mainly used for a large screen liquid crystal display device requiring high luminance because the light utilization efficiency is higher than that of the edge method.

However, the liquid crystal display device adopting the direct method is used as a large monitor or a television, so it takes longer to use than a laptop computer and the number of lamps is larger, so that the liquid crystal of the direct method is lower than the edge type liquid crystal display device. It is more likely that a lamp that will not turn on will appear due to the failure and life of the lamp in the display.

In addition, in the edge method in which the lamp units are installed on both side surfaces of the light guide plate, due to the life and failure of the lamp, for example, when only one lamp is not turned on, only the brightness on the screen is lowered. However, in the direct method, since a plurality of lamps are installed at the bottom of the screen, for example, due to the life and failure of the lamp, if one lamp does not light up, the part where the lamp is not lit becomes significantly darker than the other part. The part that does not appear immediately on the screen.

For this reason, since the lamp is frequently replaced in the direct type liquid crystal display device, the direct type liquid crystal display device should have an easy structure for disassembling and assembling the lamp unit.

Hereinafter, a backlight unit according to the related art will be described with reference to the accompanying drawings.

1 is a schematic structural diagram of a conventional edge type backlight unit, Figure 2 is a schematic structural diagram of a conventional direct type backlight unit.

A general edge type backlight unit includes a lamp 10 emitting light as shown in FIG. 1, and a light guide plate 11 guiding light emitted from the lamp 10 and reflecting the light to the LCD panel 14. A diffusion sheet 12 for diffusing the light emitted from the upper portion of the light guide plate 11 at a predetermined angle, a prism sheet 13 for condensing the diffused light and transferring the light to the LCD panel 14; The LCD panel unit 14 formed on the top of the prism sheet 13, the fixing unit (not shown) formed on the lower portion of the light guide plate 11, and the light transmitted to the fixing unit. It is composed of a reflecting plate 16 to reflect the light to minimize the loss of light.

In addition to the above configuration, the lamp housing 18 surrounding the outside of the lamp 10 except for the light incident surface of the light guide plate 11 to reduce the loss of the outgoing light of the lamp 10 emitted to the light incident surface of the light guide plate 11 and In addition, a lamp holder 17 is further provided at both ends of the lamp 10 to fix the lamp 10 at a predetermined position and prevent excessive entry of the light guide plate 11 into the lamp 10 area.

In the above, a plurality of diffusion sheets 12 may be formed as necessary.

In FIG. 1, two lamps 10 and a lamp housing 18 are formed.

The above-described backlight unit arranges lamps on both sides of the light guide plate for a monitor, and may be applied to a notebook PC by disposing the lamp only on one side of the light guide plate differently from the above.

Next, a description will be given of a conventional direct type backlight unit as follows.

As shown in FIG. 2, a conventional backlight for a liquid crystal display device includes a plurality of light emitting lamps 1, an outer case 3 for fixing and supporting the light emitting lamps 1, and the light emitting lamps 1. Light scattering means 5a, 5b, 5c disposed between the liquid crystal panels (not shown).

The light scattering means (5a, 5b, 5c) is to prevent the shape of the light emitting lamp from appearing on the display surface of the liquid crystal panel and to provide a light source having a uniform brightness distribution as a whole, to enhance the light scattering effect A plurality of diffusion sheets, diffusion plates, and the like are disposed between the liquid crystal panels.

The inner surface of the outer case 3 is disposed with a reflector 7 so that the light emitted from the light emitting lamp 1 can be concentrated to the display unit of the liquid crystal panel, which is to maximize the utilization efficiency of the light.

The light emitting lamp 1 is a Cold Cathode Fluorescent Lamp (CCFL), and electrodes are disposed at both ends of a tube to emit light when power is applied to the electrodes, and both ends of the light emitting lamp 1 are discharged. Is fitted into grooves formed on both sides of the outer case 3.

Power lead wires 9 and 9a for transmitting power for driving the lamp are connected to both electrodes of the light emitting lamp, and the power lead wires 9 and 9a are connected to a separate connector and connected to the driving circuit. Therefore, a separate connector is required for each light emitting lamp 1.

That is, the power lead wire 9 connected to one electrode of the light emitting lamp and the power lead wire 9a connected to the other electrode are connected to one connector, and one of the power lead wires 9 and 9a is connected to the outer case 3. Bends down to connect with the connector.

However, the above-described conventional edge and direct backlight unit has the following problems.

First, since each lamp has a length corresponding to that of the liquid crystal display panel, it is difficult to adjust local brightness.                         

That is, the edge type backlight unit may improve light uniformity by using light scattering means, but it is impossible to adjust local screen brightness due to the structure using the light guide plate.

In addition, the direct type backlight unit has been researched to improve the image quality by sequentially flashing a plurality of lamps, but there is a limit in controlling the local brightness only by the method of flashing the lamps sequentially.

Second, since each lamp has a length corresponding to the length of the liquid crystal display panel, the tube voltage for driving the lamp increases as the large area liquid crystal panel is used.

The present invention has been made to solve the above problems, an object of the present invention is to provide a light emitting lamp that can lower the tube voltage, the partial luminance control and a backlight unit using the same.

The light emitting lamp according to the present invention for achieving the above object is a tube (tube) defined divided into N region; And a plurality of external electrodes formed at both ends of the tube and at boundary portions of the respective divided regions.

The external electrodes may be connected to one inverter and receive a tube voltage required for driving.

A tube voltage is applied to the adjacent external electrodes so as to have a phase difference of 180 °.                     

The backlight unit according to the present invention includes a tube divided into N regions and a plurality of first to (N + 1) external electrodes formed at both ends of the outer tube and boundary portions of the respective divided regions. Light emitting lamps; The plurality of first to (N + 1) common electrodes configured to bundle the light emitting lamps in a predetermined unit so that the first to (N + 1) external electrodes of the light emitting lamps of each unit are commonly connected to each other. It is characterized by including.

The tube of the light emitting lamp is characterized in that it is defined to be divided into N areas.

The first to (N + 1) external electrodes of the light emitting lamps provided at both ends of the outside of the tube and at the boundary of each divided area are formed at the same position.

The external electrodes of the light emitting lamps provided at the boundary of each divided region are arranged in a zigzag pattern, and the common electrodes connecting the external electrodes provided at the boundary of each divided region are also arranged in a zigzag pattern.

The light emitting lamps bundled in one unit are configured to be connected to one inverter.

Each of the adjacent first to (N + 1) external electrodes of the light emitting lamps receives a tube voltage having a phase difference of 180 ° through the first to (N + 1) common electrodes.

Hereinafter, a light emitting lamp and a backlight unit using the same according to the present invention will be described with reference to the accompanying drawings.

3 is a structural diagram of a light emitting lamp according to an embodiment of the present invention, Figures 4a and 4b is a structural diagram of the connection between the light emitting lamp and the inverter of Figure 3 and the tube voltage waveform applied to each external electrode of the light emitting lamp.

First, the light emitting lamp according to the present invention is an external electrode light emitting lamp in which a tube is dividedly driven to an N region and an external electrode is formed at both ends of the tube and at the boundary of each divided driving region.

In this case, the tube may be configured to have two or more divided regions. Hereinafter, the light emitting lamp divided into three regions will be described.

As shown in FIG. 3, the tube 30 is defined to have first, second, and third regions, and the outer ends of the tube 30 and boundary regions of the first to third divided regions. The first to fourth external electrodes 31a, 31b, 31c, and 31d are formed in the respective electrodes.

As shown in FIG. 4A, the light emitting lamp configured as described above, the first to fourth external electrodes 31a, 31b, 31c, and 31d are connected to one inverter 40 to receive a tube voltage required for driving.

In this case, as shown in FIG. 4B, each tube voltage applied from the inverter 40 to the first to fourth external electrodes 31a, 31b, 31c, and 31d has a tube voltage of 180 ° so that the adjacent external electrodes have a phase difference of 180 °. It was applied to make the voltage difference per each area maximum.

In addition, the tube voltage applied to the first to fourth external electrodes 31a, 31b, 31c, and 31d is adjusted to divide the luminance into three parts.

FIG. 4B illustrates an example in which a tube voltage is applied such that brightness is adjusted to the first region <second region <third region of the light emitting lamp.                     

In order to adjust the brightness of each region as described above, the first external electrode 31a and the second external electrode 31b have a phase difference of 180 °, apply a tube voltage of the same magnitude, and apply the third external electrode 31c and the third external electrode. 4 The external electrode 31d has a phase difference of 180 ° and a tube voltage having the same magnitude is applied, wherein the tube voltage magnitudes of the third and fourth external electrodes 31c and 31d are the first and second external electrodes 31a and 331b. ) Is larger than the tube voltage.

When the tube voltage applied to each external electrode is adjusted in this way, the luminance can be adjusted by dividing into three regions of the first region <the second region <the third region.

Hereinafter, the backlight unit using the light emitting lamp having the above configuration will be described in accordance with preferred embodiments.

First embodiment

5 is a top plan view of a backlight unit according to a first embodiment of the present invention.

As shown in FIG. 5, the backlight unit according to the first exemplary embodiment of the present invention includes a tube 50a defined in three regions, and first to second edges formed at both ends of the tube 50a and the boundary between the divided regions. A plurality of light emitting lamps 50 formed of fourth external electrodes 51a, 51b, 51c, and 51d; The first to fourth external electrodes 51a, 51b, 51c, and 51d of the light emitting lamps 50 of the respective units may be commonly connected to each other by grouping the light emitting lamps 50 in a predetermined unit. Fourth common electrodes 52a, 52b, 52c, and 52d are included.

At this time, each of the light emitting lamps 50 is defined to be divided into three, and the first to fourth external electrodes 51a, 51b, 51c, and 51d of the light emitting lamps 50 provided at the boundary of each divided region are located at the same position. Formed.                     

In the above, an example of dividing the tube 50a into three regions is provided, but the tube may be divided into two or more regions.

That is, the tube may be divided into N regions, in which case, the first to N + 1 external electrodes and the first to N + 1 common electrodes are formed.

In addition, the backlight unit according to the present invention having the above-described configuration includes, for example, 16 light emitting lamps 50, and bundles and drives four light emitting lamps 50 in units of four, and includes a tube 50a. ) Is divided into three regions, the light emitting surface of the entire backlight unit can be divided into 12 regions to differentiate the luminance to drive.

Although not shown in the drawing, the light emitting lamps bundled in one unit are driven under the control of one inverter.

As shown in FIG. 4B, a tube voltage is applied to adjacent external electrodes to have a phase difference of 180 °, and the magnitude of the tube voltage applied to each external electrode can be adjusted. In this case, a tube voltage is applied to each of the external electrodes of the light emitting lamps through the first to fourth common electrodes 52a, 52b, 52c, and 52d, and to the first to fourth common electrodes 52a, 52b, 52c, and 52d. The luminance can be controlled for each divided light emitting region by adjusting the applied tube voltage.

Second embodiment

6 is a top plan view of a backlight unit according to a second exemplary embodiment of the present invention.

Compared to the first embodiment of the present invention, the backlight unit according to the second embodiment of the present invention is characterized in that the external electrodes formed at the boundary of each divided region are arranged so that dark lines due to the external electrodes are not visible.

As illustrated in FIG. 6, a tube 60a divided into three regions, first to fourth external electrodes 61a and 61b formed at both ends of the tube 60a and at the boundary between the respective divided regions, A plurality of light emitting lamps 60 consisting of 61c and 61d; The first to fourth external electrodes 61a, 61b, 61c, and 61d of the light emitting lamps 60 of each unit may be commonly connected to each other by grouping the light emitting lamps 60 in a predetermined unit. 4 common electrodes 62a, 62b, 62c, and 62d.

In order to prevent the dark wire from being generated by the external electrodes as described above, in the second embodiment of the present invention, the second and third external electrodes 61b and 61c formed at the boundary of each divided region are arranged in a zigzag pattern. The second and third common electrodes 62b and 62c connecting the second and third external electrodes 61b and 61c to each other are also arranged in a zigzag manner.

In the above, an example of dividing the tube 60a into three regions is provided, but the tube may be divided into two or more regions.

That is, the tube may be divided into N regions, in which case, the first to N + 1 external electrodes and the first to N + 1 common electrodes are formed.

In the backlight unit according to the present invention having the above-described configuration, for example, 16 light emitting lamps 60 are provided, the light emitting lamps 60 are driven in a unit of four, and a tube 60a is driven. When divided into three regions, the light emitting surface of the entire backlight unit may be divided into 12 regions to differentiate and drive the luminance.                     

Although not shown in the drawing, the light emitting lamps bundled in one unit are driven under the control of one inverter.

As shown in FIG. 4B, a tube voltage is applied to adjacent external electrodes to have a phase difference of 180 °, and the magnitude of the tube voltage applied to each external electrode can be adjusted. In this case, a tube voltage is applied to each of the external electrodes of the light emitting lamps through the first to fourth common electrodes 62a, 62b, 62c, and 62d, and is applied to the first to fourth common electrodes 62a, 62b, 62c, and 62d. The luminance can be controlled for each divided light emitting region by adjusting the applied tube voltage.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the above embodiments, but should be defined by the claims.

The light emitting lamp of the present invention and the backlight unit using the same have the following effects.

First, by configuring a backlight unit using a light emitting lamp N divided by the external electrodes, it is possible to control the luminance by dividing the backlight unit for each divided light emitting region.

Second, when driving the light emitting lamp N divided by the external electrodes, the tube voltage for driving each divided region can be lowered by forming and driving at least three parts of the external electrode.

Claims (9)

A tube divided into N regions; A plurality of external electrodes formed at both ends of the tube and at boundary portions of the respective divided regions; Light emitting lamps, characterized in that the external electrodes formed in the boundary portion of each divided region are arranged in a zigzag. The method of claim 1, The external electrodes are connected to one inverter, respectively, the light emitting lamp, characterized in that receiving the tube voltage required for driving. The method of claim 2, And a tube voltage is applied to the adjacent external electrodes to have a phase difference of 180 °. A plurality of light emitting lamps comprising a tube divided into N regions and first to (N + 1) external electrodes formed at both ends of the tube and at boundary portions of the respective divided regions; The plurality of first to (N + 1) common electrodes configured to bundle the light emitting lamps in a predetermined unit so that the first to (N + 1) external electrodes of the light emitting lamps of each unit are commonly connected to each other. Including; And external electrodes formed at the boundary of each of the divided regions are arranged in a zigzag pattern. The method of claim 4, wherein The tube of the light emitting lamp is a backlight unit, characterized in that it is defined to be divided into N areas. delete The method of claim 4, wherein And a common electrode connecting the external electrodes formed at the boundary of each divided area to each other in a zigzag arrangement. The method of claim 4, wherein The light emitting lamps grouped in the predetermined unit are configured to be connected to one inverter. The method of claim 4, wherein And each of the adjacent first to (N + 1) external electrodes of the light emitting lamps receives a tube voltage having a phase difference of 180 ° through the first to (N + 1) common electrodes.

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