KR101107716B1 - Backlight unit - Google Patents

Abstract

To provide a backlight unit having a light emitting lamp that can increase the effective light emitting area by reducing the width of the bezel, the backlight unit for achieving the above object is the main external electrodes formed at both ends of the outside of the tube arranged in a line And a plurality of light emitting lamps having a negative external electrode extending to the transparent outside the tube; A lower supporter formed with a groove in a lower portion of the light emitting lamp and a lower end of the light emitting lamp to accommodate both ends of the plurality of light emitting lamps; First and second upper side supporters for fixing and supporting both ends of the light emitting lamp together with the lower supporters and having the same groove; And a plurality of conductive layers formed on surfaces of the lower supporter and the grooves of the first and second upper side supporters, respectively, for supplying power to the light emitting lamp.

Primary external electrode, negative external electrode, bezel, effective light emitting area, light emitting lamp

Description

Backlight Unit {BACKLIGHT UNIT}

1 is a perspective view of a conventional direct type backlight unit

2 is a view showing a connector connected to a conventional light emitting lamp

3 is a plan view illustrating a direct backlight unit according to another conventional technology

4 is a cross-sectional view taken along line II ′ of FIG. 3.

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

6 is a cross-sectional view taken along line II-II ′ of FIG. 5.

7 is a plan view illustrating a backlight unit according to a second embodiment of the present invention;

FIG. 8 is a cross-sectional view taken along line III-III ′ of FIG. 7;

Explanation of symbols on the main parts of the drawings

51, 71: light emitting lamps 52a, 52b, 72a, 72b: main external electrode

53a, 53b, 73a, 73b: negative external electrode 61, 81: lower supporter

62a, 82a: first upper side supporter 62b, 82b: second upper side supporter

The present invention relates to a backlight unit, and more particularly to a backlight unit having a light emitting lamp suitable for increasing the effective light emitting area by reducing the bezel width.

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 light weight of various electronic products, CRT has a certain limit in weight and size, and is expected to replace the liquid crystal display (LCD) and gas discharge using electro-optic effects. Plasma Display Panels (PDPs) and Electro Luminescence Displays (ELDs) using electroluminescent effects are used. Among them, research on liquid crystal displays is 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. Recently, the liquid crystal display device has been developed enough to perform a role as a flat panel display device. As it is used for a monitor of a desktop computer and a large information display device, the demand for a liquid crystal display device is continuously increasing.

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

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

In the double-edge method, the lamp unit is installed on the side of the light guide plate for guiding the light, and the lamp unit covers a lamp emitting light, a lamp holder inserted at both ends of the lamp to protect the lamp, and an outer circumferential surface of the lamp, and one side It is provided with a lamp reflector 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 uniformity of light and a long service life. It is advantageous to thin the liquid crystal display device.

On the other hand, the direct type method has been developed mainly as the size of the liquid crystal display device has increased to 20 inches or more, and a plurality of lamps are arranged 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 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 one lamp is not lit, 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 direct backlight for a liquid crystal display device according to the prior art will be described with reference to the accompanying drawings.

1 is a perspective view of a direct backlight for a conventional liquid crystal display, and FIG. 2 is a view showing a power lead wire connected to a conventional light emitting lamp and a connector.

As shown in FIG. 1, 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 an overall uniform brightness distribution, in order to enhance the light scattering effect A plurality of diffusion sheets, diffusion plates, and the like are disposed between the cells.

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) as shown in FIG. 2, and electrodes 2 and 2a are disposed at both ends of a tube to emit light when power is applied to the electrode. Both ends of the light emitting lamp 1 are fitted in grooves formed on both sides of the outer case 3 as shown in FIG. 1.

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 11 and connected to the driving circuit. Therefore, a separate connector 11 is required for each light emitting lamp 1.

That is, a power lead wire 9 connected to one electrode 2 of the light emitting lamp and a power lead wire 9a connected to the other electrode 2a are connected to one connector 11, and among the power lead wires 9 and 9a. One is bent to the bottom of the outer case (3) is connected to the connector (11).

However, in such a backlight for a liquid crystal display device, since a connector is connected to a power supply lead of a light emitting lamp and connected to a driving circuit, a connector is required for each light emitting lamp so that wiring is complicated and the thickness of the backlight is reduced. By connecting the connector to the connector by bending the power lead line, not only the work efficiency is lowered, but also a separate work is required for this, which increases the process time and decreases the productivity.

In addition, in order to connect the electrode and the connector, a hole penetrating the outer case must be drilled and both electrodes of the light emitting lamp must be inserted into the hole so that both electrodes of the light emitting lamp are exposed to the outside of the outer case. Falling and maintenance of the luminous lamp is difficult.

On the other hand, instead of the Cold Cathode Fluorescent Lamp (CCFL), a light emitting lamp is an external electrode emitting lamp (EEFL) having electrodes on both ends of the tube in order to increase the price competitiveness of a large TV. A study using lamps is being conducted.

Hereinafter, a backlight unit according to another conventional technology using an external electrode light emitting lamp will be described.

3 is a plan view illustrating a structure of a direct backlight unit according to another conventional technology, and FIG. 4 is a cross-sectional view taken along line II ′ of FIG. 3.

As shown in FIGS. 3 and 4, a plurality of light emitting lamps 31 having external electrodes 33a and 33b are disposed at both ends of the outside of the tube arranged in a line, and both ends of the plurality of light emitting lamps 31 are disposed. A lower supporter 41 formed with a groove in the lower portion and lower ends of the light emitting lamp 31 and the lower supporter 41 to fix and support both ends of the light emitting lamp 31 together with the lower supporter 41 to accommodate the same groove. It is composed of the formed first and second upper side supporters 43a and 43b. And conductive layers 42a, 42b, 42c formed on the grooved surfaces of the lower supporter 41 and the first and second upper side supporters 43a and 43b, respectively, to apply power to the light emitting lamp 31. And 42d).

The light emitting lamp 31 is configured such that the external electrodes 33a and 33b at both ends thereof are surrounded by the first and second upper side supporters 43a and 43b.

The backlight unit may be divided into an effective light emitting area and a non-light emitting area.

In this case, the non-light emitting area is a region in which the luminance falls below 1/2 of the central brightness of the lamp in the entire region of the lamp, similarly to the definition of the time until the lifetime of the lamp falls below 1/2 of the initial luminance. .

Since the non-light emitting area is lowered in luminance relative to the effective light emitting area, shortening of the non-light emitting area becomes an important factor for increasing lamp efficiency.

As described above, the non-light emitting area of the conventional backlight unit having the external electrode is defined by the first and second upper side supporters 43a and 43b formed to cover the external electrodes 33a and 33b.

As described above, the external electrodes 33a and 33b of the light emitting lamp 31 substantially coincide with the first and second upper side supporters 43a and 43b that support the lamp, and are not exposed to the inside of the effective light emitting area. .

As such, when the external electrodes 33a and 33b of the light emitting lamp 31 are configured to substantially match the first and second upper side supporters 43a and 43b, the first and second upper parts supporting the light emitting lamp 31 are provided. Since the width of the bezel corresponding to the width of the side supporters 43a and 43b should always be maintained by the width of the first and second upper side supporters 43a and 43b, the width of the bezel is narrowed so as not to emit light. There is a limit to reducing the area.

In addition, in order to apply to a large backlight unit, the length of the light emitting lamp 31 must be lengthened, and the length of the external electrodes 33a and 33b must be lengthened in proportion to the length of the light emitting lamp 31 being longer. Even in this case, the ratio of the bezel to the size of the entire liquid crystal display module increases.

Accordingly, there is a limit in reducing the non-light emitting area while maintaining the effective light emitting area in the unit light emitting module (effective light emitting area + non-light emitting area).

In addition, when the width of the bezel is narrowed, the lengths of the external electrodes 33a and 33b of the light emitting lamp 31 should be shortened to match the width of the bezel.

The present invention has been made to solve the above problems, and in particular, it is an object of the present invention to provide a backlight unit having a light emitting lamp that can increase the effective light emitting area by reducing the width of the bezel.

A backlight unit according to the present invention for achieving the above object is a plurality of light emission having a main external electrode formed at both ends of the outside of the tube arranged in a line and a negative external electrode extending to the transparent outside the tube Lamps; A lower supporter formed with a groove in a lower portion of the light emitting lamp and a lower end of the light emitting lamp to accommodate both ends of the plurality of light emitting lamps; First and second upper side supporters for fixing and supporting both ends of the light emitting lamp together with the lower supporters and having the same groove; And a plurality of conductive layers formed on surfaces of the lower supporter and the grooves of the first and second upper side supporters, respectively, for supplying power to the light emitting lamp.

The upper portion of the lower supporter is characterized in that the reflection plate is further provided.

The first and second upper side supporters may be formed to surround only the main external electrodes of the light emitting lamp.

The negative external electrode may protrude into the light emitting area.

The main outer electrode is characterized in that the same diameter as the negative outer electrode.

The main external electrode may have a larger diameter than the negative external electrode.

The conductive layers are formed by digging a groove in the longitudinal direction of the lower supporter and the first and second upper side supporters and having a conductive material embedded in the groove, or coating the conductive material on a surface on which the groove is formed without embedding. It characterized by forming.

Hereinafter, a backlight unit according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

First embodiment

FIG. 5 is a plan view illustrating the backlight unit according to the first embodiment of the present invention, and FIG. 6 is a cross-sectional view of the structure taken along line II-II ′ of FIG. 5.

As shown in FIGS. 5 and 6, the backlight unit according to the first exemplary embodiment of the present invention has main outer electrodes 52a and 52a formed at both ends of the outside of the tube arranged in a line, and extends to the outside of the tube. A lower portion of the light emitting lamp 51 and a lower portion of both ends of the plurality of light emitting lamps 51 including the transparent external negative electrodes 53a and 53b and both ends of the plurality of light emitting lamps 51. A lower supporter 61 formed with a groove in the first support, and first and second upper side supporters 62a and 62b having the same groove formed by fixing and supporting both ends of the light emitting lamp 51 together with the lower supporter 61. And conductive layers 63a, 63b, and 63c formed on surfaces of the lower supporter 61 and the grooves of the first and second upper side supporters 62a and 62b, respectively, to apply power to the light emitting lamp 51. , 63d). In addition, a reflection plate (not shown) is further provided on the lower supporter 61.

The main external electrodes 52a and 52b of the light emitting lamp 51 are surrounded by the first and second upper side supporters 62a and 62b and have the same diameter as the external external electrodes 53a and 53b.

The negative external electrodes 53a and 53b are not surrounded by the first and second upper side supporters 62a and 62b and protrude into the light emitting area. In addition, the negative external electrodes 53a and 53b are composed of transparent electrodes covered with a transparent conductive material on the outside of the tube.

The conductive layers 63a, 63b, 63c, and 63d are formed on a surface of which the grooves of the lower supporter 61 and the first and second upper side supporters 62a and 62b are formed, respectively. It may be formed by embedding a conductive material in the grooves or by coating a conductive material on the surface on which the grooves are formed without embedding.

At this time, the conductive layers 63a, 63b, 63c, and 63d serve as a power connection part connecting the light emitting lamps 51 having electrodes formed at both ends of the tube.

Although not shown in the drawing, the backlight unit having the above configuration is connected to the driving circuit through the connector connected to the light emitting lamps 51a, 63b, 63c, and 63d. The number of connectors can be greatly reduced, thereby simplifying the wiring with the driving circuit and maximizing the work efficiency.

The backlight unit configured as described above may be divided into an effective light emitting area and a non-light emitting area.

In this case, the non-light emitting area is a region in which the luminance falls below 1/2 of the central brightness of the lamp in the entire region of the lamp, similarly to the definition of the time until the lifetime of the lamp falls below 1/2 of the initial luminance. .

Since the non-light emitting area is lowered in luminance relative to the effective light emitting area, shortening of the non-light emitting area becomes an important factor for increasing lamp efficiency.

In the backlight unit of the present invention having the main external electrodes 52a and 52b and the sub external electrodes 53a and 53b as described above, the non-light emitting area includes the first and the second covering the main external electrodes 52a and 52b. It is defined by two upper side supporters 62a and 62b.

As described above, the first and second upper side supporters 62a and 62b of the light emitting lamp 51 are configured to cover only the main external electrodes 52a and 52b and extend from the main external electrodes 52a and 52b. When the external electrodes 62a and 62b are provided to protrude into the light emitting area, the widths of the first and second upper side supporters 52a and 52b supporting the main external electrodes 52a and 52b of the light emitting lamp 51 are provided. It is possible to reduce the width of the corresponding bezel, thereby increasing the effective light emitting area. That is, the width of the bezel of the entire liquid crystal display module can be reduced.

In addition, as described above, reducing the width of the bezel and increasing the effective emission area may increase the overall light efficiency.

In addition, when applied to a large backlight unit, the length of the electrode portion of the light emitting lamp 51 should be lengthened. In this case, the transparent external electrodes 53a, which are transparent to extend from the main outer electrodes 52a and 52b of the light emitting lamp 51, 53b) can reduce the ratio of the bezel to the size of the entire liquid crystal display module even if the total length of the external electrode portion is increased.

Accordingly, the effective light emitting area can be increased in the unit light emitting module (effective light emitting area + non-light emitting area) while the non-light emitting area can be reduced.

In addition, even when the main outer electrodes 52a and 52b corresponding to the bezel width are narrowly formed, the transparent outer electrodes 53a and 53b do not require a high driving voltage to emit the lamps.

Second Embodiment

FIG. 7 is a plan view illustrating the backlight unit according to the second embodiment of the present invention, and FIG. 8 is a cross-sectional view of the structure taken along line III-III ′ of FIG. 7.

As shown in FIGS. 7 and 8, the backlight unit according to the second exemplary embodiment of the present invention has main outer electrodes 72a and 72a formed at both ends of the outside of the tube arranged in a line, and extends to the outside of the tube. A lower portion of the light emitting lamp 71 and a lower portion of both ends of the plurality of light emitting lamps 71 having transparent externally formed negative electrodes 73a and 73b and both ends of the plurality of light emitting lamps 71. A lower supporter (81) formed with a groove in the first support, and first and second upper side supporters (82a and 82b) having fixed and supported both ends of the light emitting lamp (81) together with the lower supporter (81). And conductive layers 83a, 83b, and 83c formed on the surfaces of the lower supporter 81 and the grooves of the first and second upper side supporters 82a and 82b, respectively, to apply power to the light emitting lamp 71. , 83d). In addition, a reflection plate (not shown) is further provided on the lower supporter 81.

The main external electrodes 72a and 72b of the light emitting lamp 71 are surrounded by the first and second upper side supporters 82a and 82b and have a larger radius of the tube than the negative external electrodes 73a and 73b. Consists of. As described above, since the diameter of the electrode portion of the main external electrodes 72a and 72b of the light emitting lamp 71 is larger than that of the negative external electrodes 73a and 73b, the wall charge amount may be increased.

In addition, the negative external electrodes 73a and 73b are not covered by the first and second upper side supporters 82a and 82b and protrude into the light emitting area to be exposed. In addition, the negative external electrodes 73a and 73b are composed of transparent electrodes covered with a transparent conductive material on the outside of the tube.

The conductive layers 83a, 83b, 83c, and 83d are formed on a surface where the grooves of the lower supporters 81 and the first and second upper side supporters 82a and 82b are formed, and grooves are formed in the longitudinal direction of each supporter. It may be formed by embedding a conductive material in the grooves or by coating a conductive material on the surface on which the grooves are formed without embedding.

At this time, the conductive layers 83a, 83b, 83c, and 83d serve as a power connection part for connecting the light emitting lamps 71 in which electrodes are formed at both ends of the outer tube.

Although not shown in the drawing, the backlight unit having the above structure is connected to the driving circuit through one connector connected to the conductive layers 83a, 83b, 83c and 83d. The number of connectors can be greatly reduced, thus simplifying the wiring with the driving circuit and maximizing the work efficiency.

The backlight unit configured as described above may be divided into an effective light emitting area and a non-light emitting area.

In this case, the non-light emitting area is a region in which the luminance falls below 1/2 of the central brightness of the lamp in the entire region of the lamp, similarly to the definition of the time until the lifetime of the lamp falls below 1/2 of the initial luminance. .

Since the non-light emitting area is lowered in luminance relative to the effective light emitting area, shortening of the non-light emitting area becomes an important factor for increasing lamp efficiency.

In the backlight unit of the present invention having the main external electrodes 72a and 72b and the sub external electrodes 73a and 73b as described above, the non-light emitting area includes the first and the second covering the main external electrodes 72a and 72b. It is defined by two upper side supporters 82a and 82b.

As described above, the first and second upper side supporters 82a and 82b of the light emitting lamp 71 are configured to cover only the main external electrodes 72a and 72b and extend from the main external electrodes 72a and 72b. When the external electrodes 82a and 82b are provided to protrude into the light emitting area and are exposed, the first and second upper side supporters 72a and 72b of the main external electrodes 72a and 72b of the light emitting lamp 71 are exposed. It is possible to reduce the width of the bezel corresponding to the width, thereby increasing the effective light emitting area. That is, the width of the bezel of the entire liquid crystal display module can be reduced.

In addition, as described above, reducing the width of the bezel and increasing the effective emission area may increase the overall light efficiency.

In addition, when applied to a large backlight unit, the length of the electrode portion of the light emitting lamp 71 should be lengthened. In this case, the transparent external electrode 73a, which extends from the main external electrodes 72a and 72b of the light emitting lamp 71, is used. 73b) can reduce the ratio of the bezel to the size of the entire liquid crystal display module even if the total length of the external electrode portion is increased.

Accordingly, the effective light emitting area can be increased in the unit light emitting module (effective light emitting area + non-light emitting area) while the non-light emitting area can be reduced.

In addition, even when the main external electrodes 72a and 72b corresponding to the bezel width are narrowly formed, the transparent external external electrodes 73a and 73b do not require a high driving voltage to emit the lamps.

In addition, the main external electrodes 72a and 72b according to the embodiment have a larger wall charge than the external electrodes having the same length. Conversely, in order to maintain the same wall charge amount, the length thereof can be made shorter than that of the external electrode having a narrow diameter. As such, when the length of the main external electrode is short, the width of the first and second upper side supporters 72a and 72b surrounding the main external electrode may be reduced, and thus the width of the bezel may be reduced.

The present invention is not limited to the above embodiments, and includes various forms that can be easily derived by those skilled in the art from the above embodiments.

On the other hand, such embodiments of the present invention can be used as a light source at the rear or front of various display devices, including a liquid crystal display device, as well as a light emitting device itself.

The backlight unit according to the present invention as described above has the following effects.

First, an effective light emitting area of the entire backlight unit can be increased by providing transparent negative external electrodes so as to protrude into the light emitting area so as to extend with the main external electrode at both ends of the tube.

Second, since the main outer electrode is formed with a wide diameter, the length of the main outer electrode can be reduced when the same wall charge is to be realized, and thus the width of the first and second upper side supporters can be reduced. Therefore, the light efficiency can be further increased by increasing the effective light emitting area of the backlight unit.

Claims (7)

A plurality of light emitting lamps having main external electrodes formed at both ends of the outside of the tube arranged in a row and negative external electrodes extending to the main external electrode to be transparent; A lower supporter having grooves formed below the light emitting lamp and below both ends of the light emitting lamp to accommodate both ends of the plurality of light emitting lamps; First and second upper side supporters for fixing and supporting both ends of the light emitting lamp together with the lower supporters and having grooves identical to those of the lower supporters; And a plurality of conductive layers formed on surfaces of the lower supporter and the grooves of the first and second upper side supporters, respectively, for supplying power to the light emitting lamp. The main external electrode has a larger diameter than the negative external electrode. The method of claim 1, The backlight unit, characterized in that the upper portion of the lower supporter is further provided with a reflecting plate. The method of claim 1, The first and second upper side supporters are formed so as to surround only the main external electrodes of the light emitting lamp. The method of claim 1, The negative external electrode protrudes into the light emitting area. delete delete The method of claim 1, The conductive layers are formed by digging a groove in the longitudinal direction of the lower supporter and the first and second upper side supporters to form a conductive material embedded in the groove, or to coat a surface on which the groove is formed without being embedded. The backlight unit, characterized in that formed by.

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