KR20010001119A - Backlight unit for liquid crystal display device - Google Patents

Abstract

PURPOSE: A backlight unit for an LCD(Liquid Crystal Display) is provided to prevent a generation of a stray capacitance between a lamp and an inverter by improving a structure of a lamp and reducing a distance between the lamp and the inverter. CONSTITUTION: An inverter(60) is arranged in an end of a light incident plate corresponding to a folded portion of lamps(20). The inverter(60) is electrically connected with each lamp(20) with a wire(21) and a connector(61). The inverter(60) converts a DC from an external power to an AC and outputs into the lamps(20). Each lamps(20) is formed an L-character shape in a front edge of the light incident plate(40) by folding in left and right corners of the light incident plate(40). Thereby, the lamps(20) are arranged near the inverter(60).

Description

Backlight unit for liquid crystal display device

The present invention relates to a backlight unit for a liquid crystal display device, and more particularly, through an improvement in the structure of a lamp, by greatly increasing the overall amount of light incident on the light guide plate, the image panel has a luminance of a certain level or more without assistance of sheets. The present invention relates to a backlight unit for a liquid crystal display device capable of displaying an image.

Recently, as the modern society becomes information socialized, the importance of the liquid crystal display, which is one of the information display devices, is gradually increasing.

In such a liquid crystal display device, in particular, the role and function of the backlight unit is becoming an important task. This is because the size and light efficiency of the liquid crystal display device vary depending on the structure of the backlight unit, so that the overall mechanical and optical characteristics of the liquid crystal display device are many. Because it is affected.

The structure of a conventional backlight for a liquid crystal display device is, for example, US Patent No. 5567042 "Reflector for flat panel display backlight unit", US Patent No. 5592193 "Backlit array for LCD display panel" (Backlighting arrangement for LCD display panel), US Patent No. 5608553 "Back light for liquid crystal display", US Patent No. 5640483 "Backlighting system using total internal reflection utilizing total internal reflection ".

In such a conventional backlight unit for a liquid crystal display device, a plurality of sheets are generally interposed between the front of the light guide plate and an image panel such as an LCD panel. By spreading in the direction, the final output image through the image panel serves to maintain the brightness of a predetermined level or more.

On the other hand, in a conventional backlight unit for a liquid crystal display device, a lamp used as a light source of the device, for example, a straight-type lamp is arranged on one side of the light guide plate, and the lamp is surrounded by a lamp cover. Form a structure.

At this time, the lamp is driven by the electrical energy input from the inverter in the state of being connected to the inverter through an electric conductor having a length of 50 mm or more, for example, by injecting a predetermined amount of light rays into the light guide plate, the image information desired by the user is displayed on the image panel. To be displayed quickly. In this case, the lamp is disposed on one side of the light guide plate, for example, a long axis, and the inverter is disposed on the other side of the light guide plate, for example, a short axis.

In the conventional production line, the light quantity of the lamp and the number of sheets are linked to each other to adjust the brightness of the image finally output through the image panel to an appropriate range, so that the image output through the image panel is always above a certain level. It is trying to maintain the image quality.

However, there are some serious problems in operating such a conventional backlight unit for a liquid crystal display.

As described above, the conventional straight-type lamp is arranged on the long axis of the light guide plate, while the inverter is arranged on the short axis of the light guide plate. In this case, the distance between the lamp and the inverter is farther than necessary. Inevitably, the production line has to bear the problem of generating unnecessary stray capacitance around the wire connecting the lamp and the inverter. Such stray capacitance is continuously present in the assembled liquid crystal display device, and acts as a defect factor that degrades the function of the liquid crystal display device, resulting in a poor quality of the finally shipped liquid crystal display device.

In order to remove such stray capacitance, it is best to reduce the distance between the lamp and the inverter. However, as described above, the conventional lamp has a straight structure and is arranged on the side of the light guide plate, for example, on the long axis. In addition, since the inverter has a structure arranged on the other side of the light guide plate, for example, a short axis, the production line does not provide any other countermeasures for reducing the distance between the lamp and the inverter.

On the other hand, as described above, the conventional production line proceeds the process of linking the number of sheets of light and the number of sheets so that the image output through the image panel can maintain a certain level or more image quality.

However, when the sheets are arranged in the structure of the backlight unit for the liquid crystal display device, the advantages such as "improving the brightness of the output light" and "improving the viewing angle of the output light" can be secured. Rises, mechanical reliability is greatly degraded, and other problems arise that the thickness of the device becomes very difficult. Therefore, the conventional production line is making an effort to reduce the overall number of these sheets.

However, if the number of sheets is reduced, the brightness of the image finally output to the image panel is greatly reduced, and thus, the production line does not significantly reduce the number of sheets, while reducing the problems of sheets.

Accordingly, it is an object of the present invention to improve the structure of a lamp and thereby significantly reduce the distance between the lamp and the inverter, thereby preliminarily suppressing the generation of stray capacitance existing between the lamp and the inverter.

Another object of the present invention is to ensure the quality of the final liquid crystal display device to a predetermined level or more by suppressing stray capacitance.

Another object of the present invention is to increase the overall amount of light incident on the light guide plate through the structure improvement of the lamp, so that the image panel can display an image having a certain level or more of brightness without assistance of sheets.

Still another object of the present invention is to significantly reduce the total number of sheets disposed in the backlight unit, thereby reducing the overall manufacturing cost of the apparatus and stably securing mechanical reliability.

Still other objects of the present invention will become more apparent from the following detailed description and the accompanying drawings.

1 is a perspective view illustrating a rear surface of a backlight unit for a liquid crystal display according to the present invention.

2A to 2C are enlarged views of main parts of FIG. 1;

3 is a perspective view illustrating a rear surface of a backlight unit for a liquid crystal display according to another exemplary embodiment of the present invention.

In order to achieve the above object, in the present invention, the lamps are arranged to be paired with each other on both sides of the light guide plate, and the respective lamps are first bent at the left and right corners of the light guide plate, so that each lamp is formed on both sides of the long axis of the light guide plate and either side. For example, the front short edge may be wrapped in an "L" character shape. In this case, the lamps are changed from the conventional "straight-type structure" to the "el-shaped structure", and the light guide plate is formed by a lamp wrapped around its left and right major axis edges and the front minor axis edge, which is larger than the conventional case. By being irradiated with the light beam, it is possible to expand its overall effective light emission field, and eventually output a larger amount of light to the image panel disposed above it. As a result, in the production line, it is possible to obtain the effect that the brightness of the image finally output to the image panel is greatly increased.

When the present invention is achieved, since the total amount of light incident on the light guide plate is greatly increased, the production line can display an image having a certain level or more of brightness without the assistance of sheets, and thus is disposed in the backlight unit. The total number of sheets can be greatly reduced, and as a result, the overall manufacturing cost of the apparatus can be greatly reduced, as well as the mechanical reliability of the apparatus can be secured stably.

At this time, as described above, each of the lamps of the present invention are first bent at the left and right corners of the light guide plate to form an "L" shape at the front short edge of the light guide plate, and thus, a distance very close to the inverter disposed at the short edge of the light guide plate. Can be maintained.

When the present invention is achieved, since both the "end of the lamp and the inverter" is arranged in the short axis of the light guide plate, the production line can achieve the effect of greatly reducing the distance between the lamp and the inverter, and eventually, the lamp The generation of stray capacitance existing between the inverter and the inverter can be suppressed in advance, and as a result, the quality of the finally shipped liquid crystal display device can be secured to a predetermined level or more.

Hereinafter, a backlight unit for a liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, in the backlight unit for a liquid crystal display according to the present invention, a light guide plate 40 is disposed inside a storage space of a mold frame 10 having a rectangular ring shape by sidewalls 11. The light guide plate 40 changes the light beam of the line light source output from the lamp 20 into the light beam of the surface light source, and then outputs the changed light beam toward the image panel (not shown) disposed on the front surface of the light guide plate 40. In this case, a back chassis 80 is disposed on the rear surface of the mold frame 10, and the back chassis 80 covers the rear surface of the light guide plate 40 and the lamp 20 to protect them from external shocks. Play a role. Of course, on the opposite side of the back chassis 80, that is, the front of the light guide plate 40, a plurality of sheets (not shown) are arranged to diffuse the light beams output from the lamp 20, and the front of the sheets An image panel is placed in the display panel, and serves to display image information desired by a user to the outside.

At this time, both sides of the light guide plate 40 are provided with a lamp 20 used as a light source of the liquid crystal display device, such a lamp 20 forms a structure wrapped by the lamp cover (30).

Here, as shown in the figure, the lamp 20 of the present invention has a structure that is arranged opposite to each other on both sides of the light guide plate 40, and, for example, primary in the front left and right corners of the light guide plate 40 It is bent to form a structure that surrounds both the long axis edges of the light guide plate 40 and the front minor axis edges of the light guide plate 40 in an "L" shape.

Such a structure of the lamp 20 forms the gist of the present invention, and, of course, the conventional lamp is completely different from the "intuitive", and has a structure that is arranged on both sides of the light guide plate.

When the lamp 20 of the present invention has the above-described structure, the light guide plate 40 is irradiated with a greater amount of light rays than the conventional case by the lamp 20 wrapped around its left and right long axis and front short axis. By doing so, it is possible to greatly enlarge the overall effective light emission area of the user, and finally, it is possible to output a larger amount of light rays toward the image panel disposed on the front side. As a result, in the production line, it is possible to obtain the effect that the brightness of the image finally output to the image panel is greatly increased.

When the present invention is achieved, since the total amount of light incident on the light guide plate 40 is greatly increased, in the production line, an image having a certain level or more of brightness can be displayed to the outside without the assistance of sheets. The total number of sheets disposed in the backlight unit can be greatly reduced. In this case, in the production line, the overall manufacturing cost of the device is greatly reduced, and the mechanical reliability of the device can be obtained.

In this case, as shown in the figure, the inverter 60 is disposed on the short axis of the light guide plate corresponding to the portion where the lamps 20 are bent, and the inverter 60 is connected to the wire 21 and the connector 61. As a result, a structure is electrically connected to each of the lamps 20. In this case, the inverter 60 receives a DC voltage from an external power source, converts the DC voltage into an AC voltage suitable for driving the lamp 20, and outputs the DC voltage to the lamps 20.

Here, as described above, each of the lamps 20 of the present invention is first bent at the left and right corners of the light guide plate 40, so as to form an "L" shape on the front short edge of the light guide plate 40, the light guide plate ( It is possible to maintain a very close distance to the inverter 60 disposed on the short edge of the 40.

When the present invention is achieved, since the "end of the lamp and the inverter" can all be arranged in the short axis of the light guide plate 40, the distance between the lamp 20 and the inverter 60 in the production line is significantly A reduction effect can be obtained, and eventually, generation of stray capacitance existing between the lamp 20 and the inverter 60 can be suppressed in advance, and finally, the quality of the liquid crystal display device finally delivered to a certain level or more is secured. can do.

At this time, as shown in the figure, the mold frame containing the light guide plate 40, the lamp 20, etc. forms a structure in which the side wall 11 corresponding to the bent portion of the lamps 20 is opened. The open area of the mold frame serves as an entrance gate for smooth entry and exit of the lamps 20 when replacement of the lamps 20 is required.

In the production line, when the lamps 20 stored in the storage space of the mold frame 10 run out, and the lamps 20 need to be replaced with new lamps, the open area of the mold frame 10 described above. After securing the entrance gate of the lamps 20 through, by pulling the lamp cover 30 covering the lamps in the direction of the arrow, to achieve a smooth replacement of the lamps 20, the liquid crystal display Allows the device to maintain image quality above acceptable levels for a long time.

In this case, a cover plate 70 covering the lamps 20 is additionally mounted in the open area of the mold frame 10. In the production line, when the lamps 20 and the light guide plate 40 described above are accommodated in the storage space of the mold frame 10, and the rear surface of the mold frame 10 is covered by the back chassis 80, the cover plate 70 is entered into the open area of the mold frame 10, and the work of fixing the cover plate 70 to the mold frame 10, the back chassis 80, etc. is performed. In this case, in the production line, the screw is inserted into the screw hole 71 to fix the upper plate of the cover plate 70 to the back chassis 80, and the screw is inserted into the screw hole 72 to cover the plate 70. The lower plate of the is fixed to the mold frame 10.

When the cover plate 70 covers the open area of the mold frame 10 through this process, in the production line, foreign matters of the outside may contaminate the problem of contaminating the inside of the mold frame 10, as well as lamps. The mounting reliability of 20 can also be ensured stably.

On the other hand, as shown in Figure 2a, the above-described light guide plate 40 is formed with a plurality of reflective dots 41 for diffusing the light incident from the lamps (20). The reflecting dots 41 keep their size small in the area adjacent to the lamps 20, for example, the left and right sides of the light guide plate 40, leading to a decrease in the total amount of light diffusion and constant with the lamps 20. In the distance-distance region, for example, the center of the light guide plate 40, the size is kept large, leading to an increase in the total amount of light diffusion. In this case, the light guide plate 40 may maintain a uniform amount of light spread over its entire surface. As a result, the light beam output to the image panel via the light guide plate 40 may have uniform luminance across the front surface of the light guide plate 40. Can be represented.

At this time, in the production line, as shown in the drawing, compared to other areas of the light guide plate 40, an area in which the "light rise phenomenon" is expected, for example, the bent portion of the lamps 20, the lamps 20 are spaced apart from each other. The density of the reflective dots 41 formed in the region corresponding to the marked portion is greatly increased.

For example, in the production line, the light beams output from the regions A and C are increased by densifying the intervals of the reflection dots 41 formed in the regions A and C corresponding to the bent portions of the lamps 20 and increasing their density. This leads to a significant increase in the diffusion of. In this case, although the amount of the incident light beams due to the bending of the lamps 20 decreases, the light guide plate 40 can greatly increase the luminance of the output light beams through the auxiliary action of the reflective dots 41. As a result, the production line can achieve an effect of blocking the unexpected light shine phenomenon.

In another example, in the production line, the distance between the reflecting dots 41 formed in the region B corresponding to the spaced portions of the lamps 20 is dense, and the density thereof is increased, whereby the amount of light emitted from the region B is diffused. Induce it to increase significantly. In this case, although the amount of the incident light beams due to the separation of the lamps 20 decreases, the light guide plate 40 may greatly increase the luminance of the output light beams through the auxiliary action of the reflecting dots 41. As a result, the production line can achieve an effect of blocking the unexpected light shine phenomenon.

Such increase in density of the reflecting dots 41 may be achieved by adjusting the spacing between the reflecting dots 41 as described above, but in another example, may be achieved by increasing the size of the reflecting dots 41. have. In this case, in the production line, the size of the reflecting dots 41 formed in the regions A, B, and C are enlarged, and the density thereof is increased, so that the amount of diffused light rays output from the regions A, B, and C can be greatly increased. Induce. Of course, even in this case, even though the light guide plate 40 has a small amount of incident light due to the bending of the lamp 20, the separation of the lamp 20, or the like, through the auxiliary action of the reflective dots 41, Luminance of the output light beams can be greatly increased, and as a result, an effect of blocking the "light lumping phenomenon" which is unexpected in the production line can be obtained.

On the other hand, as shown in the figure, the stopper 50 is further disposed on at least one edge of the light guide plate 40, for example, the front left and right edges of the light guide plate 40. The stopper 50 has a cylindrical shape, for example, a rectangular cylindrical shape, protrudes from the bottom surface of the mold frame 10, and is formed integrally with the mold frame 10. In this case, the stopper 50 is in close contact with the front left and right edges of the light guide plate 40 to limit the flow width of the light guide plate 40 to a certain range, so that the light guide plate 40 may be exposed even if an external impact reaches the light guide plate 40. The movement is blocked to prevent flow toward these ramps 20.

Due to the action of the stopper 50, the light guide plate 40 can maintain a stable fixed state for a long time, as a result, "damage of the lamp" due to the collision with the light guide plate 40 can be prevented in advance.

In this case, as illustrated in FIG. 2B, a plurality of impact dispersion walls 51 are formed inside the stoppers 50 to disperse the shock transmitted from the light guide plate 40.

Such impact dispersion walls 51 may have, for example, a “+” shape and may be formed across the inside of the stoppers 50, and as another example, as shown in FIG. It forms a shape and may be formed across the inside of the stoppers 50. Due to the action of the impact dispersion walls 51, the impact transmitted from the light guide plate 40 to the stopper 50 may be dispersed in various directions, and the stopper 50 may stabilize the light guide plate 40 fixed role given thereto. It can be done with Of course, the impact dispersion walls 51 described above may have various shapes, for example, an “×” shape, a “＼” shape, and the like, in addition to the structure shown in the drawing. Each shape of the impact dispersion walls 51 may be variously selected according to the situation of the production line.

On the other hand, as shown in Figure 3, in another embodiment of the present invention, the inverter 60 is divided and disposed in pairs so as to correspond to each of the lamps one-to-one.

As such, when the inverters 60 are divided and arranged in pairs, the assembly process of the whole apparatus is more complicated, but the lamp 20 in charge of the inverter 60 is divided into left and right sides, and each inverter 60 may control the tube current input to each of the lamps 20 on the left and right differently, and thus, in the production line, the number of lamps 20 arranged on the left and right sides may be advantageously obtained.

In addition, according to another embodiment of the present invention, the cover plate 70 is disposed by dividing the cover plate 70 into pairs so as to correspond one to one with each other.

Of course, even in this case, the assembly process of the overall apparatus will be more complicated, but the lamp 20 covered by the cover plate 70 is divided into left and right sides, and each cover plate 70 is disposed on the left and right sides. Since the open area of the mold frame 10 can be selectively opened and closed according to the individual situation of the lamps 20, the production line can obtain the advantage of more effectively managing the inflow of foreign objects.

For example, when the lamp 20 disposed on the left side of the light guide plate 40 is to be replaced, in the production line, the left lamp cover cover plate 100 is dismantled to secure an entrance gate of the lamps 20. The lamp 20 arranged on the left side can be pulled in the direction of the arrow to achieve smooth replacement of the lamp 20 arranged on the left side. In this case, since only the lamp 20 arranged on the left side of the light guide plate 40 is opened, the lamp 20 arranged on the right side of the light guide plate 40 is covered by the right lamp cover plate 90, so that the production In the line, it is possible to minimize the inflow of foreign foreign matter.

Of course, in another embodiment of the present invention, the lamps 20 are first bent at the front left and right corners of the light guide plate 40, so that both long axis edges of the light guide plate 40 and the front short axis edges of the light guide plate 40 are “el. "Because the structure is wrapped in a shape, the light guide plate 40 is irradiated with a larger amount of light rays than the conventional case by the lamp 20 wrapped around its left and right long axis borders and front side short edges, The overall effective light emission field can be greatly enlarged, and as a result, a larger amount of light can be output to the image panel disposed on the front side. As a result, in the production line, it is possible to obtain the effect that the brightness of the image finally output to the image panel is greatly increased.

In addition, since both the "end of the lamp and the inverter" can be arranged in the short axis of the light guide plate 40, the production line can obtain the effect that the distance between the lamp 20 and the inverter 60 is significantly reduced. As a result, generation of stray capacitance existing between the lamp 20 and the inverter 60 can be suppressed in advance, and as a result, the quality of the finally shipped liquid crystal display device can be secured to a predetermined level or more.

As described above, in the present invention, through the structural improvement of the lamp, the amount of light of the entire lamp incident on the light guide plate is greatly increased, so that the image panel can display an image having a certain level or more of brightness without assistance of sheets. Can be induced.

The present invention has an overall useful effect in all kinds of liquid crystal display devices, for example, liquid crystal display devices for monitors manufactured in the production line.

And while certain embodiments of the invention have been described and illustrated, it will be apparent that the invention may be embodied in various modifications by those skilled in the art.

Such modified embodiments should not be understood individually from the technical spirit or point of view of the present invention and such modified embodiments should fall within the scope of the appended claims of the present invention.

As described in detail above, in the backlight unit for a liquid crystal display according to the present invention, the lamps are arranged to be paired with each other on both sides of the light guide plate, and the respective lamps are first bent at the left and right corners of the light guide plate, so that each lamp is light guide plate. Both sides of the long axis border and front short axis border to be wrapped in the "L" shape.

When the present invention is achieved, since the total amount of light incident on the light guide plate is greatly increased, the production line can display an image having a certain level or more of brightness without the assistance of sheets, and thus is disposed in the backlight unit. The total number of sheets can be greatly reduced, and as a result, the overall manufacturing cost of the apparatus can be greatly reduced, as well as the mechanical reliability of the apparatus can be secured stably.

In addition, when the present invention is achieved, since both the "end of the lamp and the inverter" is arranged in the short axis of the light guide plate, in the production line it is possible to obtain the effect of greatly reducing the distance between the lamp and the inverter, The generation of stray capacitance existing between the lamp and the inverter can be suppressed in advance, and as a result, the quality of the finally shipped liquid crystal display device can be secured to a predetermined level or more.

Claims (11)

A mold frame having a rectangular ring shape having a storage space; A light guide plate accommodated in a storage space of the mold frame and having a plurality of reflective dots; First bent at the left and right corners of the light guide plate, and wrapped around the long axis border and one short axis border of the light guide plate in the form of an "L" (L-character), are arranged opposite to each other, the electrical energy input from the outside A pair of lamps driven by the lamp to irradiate a predetermined amount of light to the light guide plate; An inverter disposed on one axis of the light guide plate corresponding to the bent portion of the lamps, electrically connected to the lamps via a wire, and converting an external DC voltage into an AC voltage to output the lamps; Backlight unit for a liquid crystal display device comprising a. The backlight unit of claim 1, wherein the mold frame has a structure in which sidewalls corresponding to the bent portions of the lamps are opened so that the lamps can be smoothly replaced. The backlight unit of claim 2, wherein a cover plate covering the lamps is further mounted in an open area of the mold frame. The backlight unit of claim 1, wherein a stopper is further disposed at at least one edge of the light guide plate to prevent the light guide plate from flowing. The backlight unit of claim 4, wherein the stopper is integrally formed with the mold frame. 6. The backlight unit of claim 5, wherein the stopper has a cylindrical shape. The backlight unit of claim 6, wherein the stoppers further include a plurality of impact dispersion walls therein so that impacts transmitted from the light guide plate may be dispersed. The backlight unit of claim 1, wherein the inverters are divided into pairs so as to correspond one-to-one with each of the lamps. The backlight unit of claim 1, wherein the reflective dots maintain a higher density in a region corresponding to the bent portion of the lamps than in other regions. The backlight unit of claim 9, wherein the reflective dots maintain a high density by increasing their size. 10. The backlight unit of claim 9, wherein the reflective dots maintain a high density by adjusting a gap between them.