KR20070118388A - Backilght unit and liquid crystal display device module with the same - Google Patents

Abstract

A backlight unit and an LCD(Liquid Crystal Display) module using the same are provided to apply all light emitted from a fluorescent lamp to a light guide plate by mounting the fluorescent lamp within the light guide plate and configuring both four edges of the light guide plate with parabolic mirrors, thereby preventing light loss caused by a lamp guide and reducing costs. A backlight unit comprises a reflecting plate, a light guide plate(123) and plural optical sheets. The light guide plate is mounted on an upper part of the reflecting plate. Within the light guide plate, a fluorescent lamp(129) is mounted. The plural optical sheets are mounted on the light guide plate. Both four edges of the light guide plate are configured with parabolic mirrors. One side of a light guide plate length direction is configured with a first parabolic mirror(133a), and the other side of the light guide plate length direction facing the first parabolic mirror is configured with a second parabolic mirror(133b).

Description

Backlight unit and liquid crystal display device module with the same

1 is a view schematically showing a structure of a general light guide plate and a fluorescent lamp for injecting light into the light guide plate.

2 is an exploded perspective view of a liquid crystal display module according to the present invention.

Figure 3 is a schematic view showing the structure of a light guide plate mounted therein a fluorescent lamp according to the present invention.

4 is a view schematically illustrating a path of light in a light guide plate in which the fluorescent lamp of FIG. 3 is mounted;

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

123: light guide plate 129: fluorescent lamp

133a, 133b: first and second parabolic diameters

The present invention relates to a backlight unit for a liquid crystal display device, and more particularly to a structure of a light guide plate.

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 an anisotropy having an orientation in the array. It is polarized. 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, it requires a separate light source. 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 largely divided into a direct method and an edge method. The direct method includes a fluorescent lamp located at a lower end of the liquid crystal panel, in which light is directly incident on the front surface of the liquid crystal panel, and consumes high power. It is expensive and has a disadvantage in that the thickness of the liquid crystal display becomes thick.

In contrast, in the edge method, a cold cathode flurescent lamp (CCFL) is mainly used as a method of injecting light into a light guide plate and a reflecting plate by placing a fluorescent lamp on one or both sides of the liquid crystal panel. Lightweight and low power consumption is currently being used widely.

In the edge-type backlight unit, a light guide panel (LGP) for scattering light emitted from the fluorescent lamp and implementing it as a surface light source will be described in more detail.

1 is a view schematically illustrating a structure of a general light guide plate and a fluorescent lamp for injecting light into the light guide plate.

As shown, the light guide plate 23 is configured such that the parallel upper surface and the lower surface corresponding to the upper surface is inclined, that is, the light guide plate 23 is a thick light incident portion provided with a fluorescent lamp 29 and the fluorescent light It is formed in the form of a panel inclined to become thinner away from the lamp (29).

The fluorescent lamp 29 is arranged along the length direction of the light receiving part of the light guide plate 23, and guides the upper and lower outer sides of the fluorescent lamp 23 to emit light F above and below the fluorescent lamp 29. ) Is further provided with a lamp guide 33 for re-incident toward the light guide plate 23.

As a result, the light F emitted from the fluorescent lamp 29 is incident into the light guide plate 23 through the light incidence part of the light guide plate 23 through the opened surface of the lamp guide 33.

The incident light F spreads evenly over a wide area of the light guide plate 23 while traveling in the light guide plate 23 by a plurality of total reflections, thereby providing a surface light source to the liquid crystal panel (not shown).

That is, the light F emitted from the fluorescent lamp 29 is spread widely inside the light guide plate 23 through the light guide plate 23 incident part, and passes through the plurality of optical sheets 21 interposed on the light guide plate 23. It is delivered to a liquid crystal panel (not shown).

However, the light F emitted from the fluorescent lamp 29 does not all enter the light guide plate 23. This is because the light F emitted from the fluorescent lamp 29 is partially diffused by the light incident part of the light guide plate 23, which is another medium, and is lost. Also, the fluorescent lamp 29 is not the direction in which the light guide plate 23 is located. This is because light is also emitted to the upper and lower sides of (29).

In this case, the light emitted upward and downward of the fluorescent lamp 29 may be reflected by the lamp guide 33 and re-entered into the light incident part of the light guide plate 23, and the light reflected by the lamp guide 29 may be used. (F) is also multiplexed within the lamp guide 33, the light intensity is weakened. Therefore, the amount of light F re-incident into the light guide plate 23 is not so large.

In addition, the light F incident to the inside of the light guide plate 23 after being multi-reflected is incident at an angle smaller than the total reflection grain boundary angle of the light guide plate 23, and thus bright lines are generated. Will not have

The present invention has been made to solve the above problems, and aims to minimize the loss of light emitted from the fluorescent lamp, and the first object is to inject a lot of light into the light guide plate.

In addition, it is a second object to have uniform luminance with respect to the entire liquid crystal panel.

In order to achieve the object as described above, the present invention is a reflection plate; A light guide plate mounted on an upper portion of the reflective plate and having a fluorescent lamp mounted therein; It includes a plurality of optical sheets seated on the light guide plate, both edges of the light guide plate provides a backlight unit, characterized in that consisting of a parabolic mirror.

The light guide plate is configured such that a parallel upper surface and a lower surface corresponding to the upper surface are inclined, and one side surface of the light guide plate in a longitudinal direction includes a first parabolic mirror, and the light guide plate longitudinal direction facing the first parabolic mirror. The other side of is characterized in that composed of a second parabolic, the fluorescent lamp is characterized in that provided in the focal point of the first parabolic along the longitudinal direction of the light guide plate.

The first and second parabolic mirrors may be mirror-coated or the first and second parabolic mirrors may be formed of silver (Ag) or aluminum (Al) metal. A variety of patterns such as dot patterns are printed.

The light guide plate may be formed of polymethylmethacrylate (PMMA), which is one of acrylic transparent resins, which are transparent materials.

The present invention also includes a liquid crystal panel mounted above the backlight unit including a light guide plate mounted inside the fluorescent lamp; A support main frame that borders the backlight unit and the liquid crystal panel; A cover bottom covering a rear surface of the support main; It includes a top cover that borders the front edge of the liquid crystal panel, both sides of the light guide plate provides a liquid crystal display module, characterized in that consisting of a parabolic mirror.

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

2 is an exploded perspective view of a liquid crystal display module according to the present invention.

As illustrated, the liquid crystal display module includes a liquid crystal panel 111, a backlight unit 120, a support main 127, a cover bottom 135, and a top cover 113.

That is, as shown in the figure, the backlight unit 120 and the liquid crystal panel 111 are sequentially stacked on the upper surface of the rectangular main frame support main shape 127 having one edge open, thereby preventing the deformation of the support main shape 127. The cover bottom 135 is coupled along the rear surface of one open edge of the support main 127, and the top cover 113 bordering the edge of the liquid crystal panel 111 is fixed to the support main 127 so as to fix them all. ) And the cover bottom 135 is assembled and fastened.

In this case, a printed circuit board 117 connected through a flexible printed circuit board 115 is connected along at least one side of the liquid crystal panel 111, and the backlight unit 120 is connected to the backlight unit 120. A reflector plate 125 of a white or silver sheet interposed on an upper surface of the support main 127, a light guide plate 123 mounted on the reflector plate 125, and a fluorescent lamp 129 mounted therein; The optical sheet 121 of the.

The plurality of optical sheets 121 serve to propagate the light emitted from the fluorescent lamp 129 toward the liquid crystal panel 111 and to allow incident light at a wide range of angles, thereby improving light efficiency. Play a role.

In this case, one side of the light guide plate 123 in which the fluorescent lamp 129 is mounted, and the other side includes first and second parabolic diameters.

In the above-described configuration, one fluorescent lamp 129 is mounted on one side of the light guide plate 123, but a plurality of fluorescent lamps 129 may be mounted depending on the purpose.

3 is a view schematically illustrating a structure of a light guide plate having a fluorescent lamp mounted therein according to the present invention.

As illustrated, the light guide plate 123 is configured such that a parallel upper surface and a lower surface corresponding to the upper surface are inclined, and one side surface in the longitudinal direction of the light guide plate 123 is formed of a first parabolic diameter 133a. The other side surface in the longitudinal direction of the light guide plate 123 facing the first parabolic mirror 133a includes a second parabolic mirror 133b.

That is, the light guide plate 123 is formed on the first parabolic mirror 133a by one side surface formed of the first parabolic mirror 133a and a lower surface of the light guide plate 133a that is inclined further away from the first parabolic mirror 133a. In contrast, the panel is formed of the other side surface of the second parabolic diameter 133b having a thin thickness.

The light guide plate 123 is manufactured using a plastic or resin such as PMMA (polymethylmethacrylate), an acrylic transparent resin, which is one of transparent materials capable of transmitting light.

In the light guide plate 123, a predetermined groove is formed along the longitudinal direction of the first parabolic mirror 133a, and the fluorescent lamp 129 is mounted. In this case, the fluorescent lamp 129 is mounted at the focal point of the first parabolic mirror 133a.

Therefore, since the fluorescent lamp 129 is inserted into the light guide plate 123, all of the light emitted from the fluorescent lamp 129 is incident evenly into the light guide plate 123, and thus the fluorescent lamp 129 The loss of light can be minimized as compared with the configuration of the light guide plate 123.

In addition, the fluorescent lamp 129 can be protected from an external shock, etc., and there is no need to provide a separate reflective member, and the backlight unit (120 of FIG. 2) of the liquid crystal display device can be easily assembled.

In this case, various patterns such as a fine dot pattern for changing the traveling direction of the light generated from the fluorescent lamp 129 toward the liquid crystal panel (111 of FIG. 2) are printed on the lower surface of the light guide plate 123. Inner surfaces of the first and second parabolic mirrors 133a and 133b are mirror-coated to reflect light emitted from the fluorescent lamp 129 to increase the efficiency of light emitted from the fluorescent lamp 129.

In this case, the first and second parabolic diameters 133a and 133b may be formed in the first and second parabolic diameters 133a and 133b in addition to mirror coating, such as silver (Ag) and aluminum (Al) having a reflectance of 95% or more. It can be formed using a metal.

As described above, the side edges of the light guide plate 123 are formed of parabolic mirrors 133a and 133b having high reflectance, which will be described in more detail with reference to FIG. 4.

FIG. 4 is a view schematically illustrating a path of light in a light guide plate in which the fluorescent lamp of FIG. 3 is mounted.

As shown, when the light F is emitted from the fluorescent lamp 129 mounted inside the edge side of the light guide plate 123 formed of the first parabolic diameter 133a, the light F is the light guide plate 123. As it proceeds inside, it spreads evenly over a wide area of the light guide plate 123.

At this time, since the fluorescent lamp 129 is located at the focal point of the first parabolic mirror 133a, the light F emitted from the upper and lower outer sides of the fluorescent lamp 129 is parabolic based on the first parabolic principle. Reflected by 133a, the light becomes parallel light.

That is, this is a principle that is used for headlights in a vehicle and a light fixture that is far from the target object, and when the fluorescent lamp 129 is located at the focus of the first parabolic mirror 133a, the fluorescent lamp 129 The light F emitted from is reflected by the first parabolic mirror 133a, so that the light F travels straight in a direction parallel to the axis of the first parabolic mirror 133a.

The parallel light is stronger than the non-parallel light, which is the light not reflected by the first parabolic mirror 133a, and is more widely spread. Therefore, the light F reflected by the first parabolic diameter 133a reaches the second parabolic diameter 133b as it is and is reflected again by the second parabolic diameter 133b.

At this time, the light F reflected by the second parabolic mirror 133b passes through the focal point of the second parabolic mirror 133b due to the focus reflection property of the parabola.

The focus reflection property of the parabola means that the light (F) is reflected by the first parabolic mirror (133a) and becomes parallel light. On the contrary, light or radio waves that enter parallel to the axis of the parabola are transmitted to the parabola. When the light is reflected by the parabola, the light F reflected by the second parabolic mirror 133b converges and spreads to the focal point of the second parabolic mirror 133b.

The parabolic definition by the first and second parabolic diameters 133a and 133b, that is, the light F reflected by the parabolic diameter are all directed parallel to the axis of the parabolic diameter.

As such, some of the parallel light passing through the focal point of the second parabola 133b is directed toward the upper surface of the light guide plate 123, and the plurality of optical sheets 121 interposed on the light guide plate 123 as they are. Permeate.

In addition, parallel light directed toward the lower surface of the light guide plate 123 is perpendicular to the liquid crystal panel (111 in FIG. 2) by various patterns such as a dot pattern 131 formed on the lower surface of the light guide plate 123. Will be irradiated in the direction.

As a result, the light F emitted upward and downward from the fluorescent lamp 129 is irradiated toward the liquid crystal panel (111 in FIG. 2), thereby obtaining light F having a uniform and higher luminance than the conventional light.

The light F having high luminance passes through the plurality of optical sheets 121 interposed on the light guide plate 123 and then enters the liquid crystal panel 111 of FIG. 2. 111 of FIG. 2 can finally display an image of desired luminance to the outside.

As described above, by mounting the fluorescent lamp 129 in the light guide plate 123, the light F emitted from the existing fluorescent lamp (29 in FIG. 1) is inside the light guide plate (23 in FIG. 1). It is possible to prevent the problem that part of the light (F) is lost when incident to the light, and the light (F) emitted from the upper and lower outside of the fluorescent lamp (29 of FIG. 1) of the light guide plate (23 of FIG. 1) The lamp guide (33 of FIG. 1) separately provided for re-incident to the light incident part may be deleted, and the problem that the intensity of light is weakened by multiple reflection by the lamp guide (33 of FIG. 1) is also prevented in advance. .

In addition, the fluorescent lamp 129 may be protected from an external shock, etc., and the assembling of the backlight unit 120 of FIG. 2 may be easily performed.

In addition, by configuring both longitudinal directions of the light guide plate 123 as parabolic diameters 133a and 133b, the traveling path and the reflection direction of the light F in the light guide plate 123 can be predicted. It becomes easy to design the pattern 131 provided on the lower surface of the light guide plate 123.

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 fluorescent lamp is mounted in the light guide plate according to the present invention, and both edges of the light guide plate are formed of parabolic diameters so that the light emitted from the conventional fluorescent lamp does not enter all of the light guide plate. There is an effect to prevent the problem that the light is partially lost, and by removing the lamp guide provided separately to re-enter the light emitted from the top and bottom of the fluorescent lamp to the light incident portion of the light guide plate, due to the lamp guide Light loss can be prevented and process cost can be reduced.

In addition, the fluorescent lamp can be protected from an external shock, etc., and the backlight unit of the liquid crystal display device can be easily assembled.

In addition, by configuring the longitudinal direction of both sides of the light guide plate to each of the parabolic diameter, it is possible to predict the traveling path and the reflection direction of the light inside the light guide plate, it is easy to design the pattern provided on the lower surface of the light guide plate There is.

Claims (7)

A reflector; A light guide plate mounted on an upper portion of the reflective plate and having a fluorescent lamp mounted therein; A plurality of optical sheets seated on the light guide plate And a light emitting plate having both edges formed of a parabolic mirror. The method of claim 1, The light guide plate is configured such that a parallel upper surface and a lower surface corresponding to the upper surface are inclined, and one side surface of the light guide plate in a longitudinal direction includes a first parabolic mirror, and the light guide plate longitudinal direction facing the first parabolic mirror. The other side of the backlight unit, characterized in that consisting of a second parabolic mirror. The method of claim 2, And the fluorescent lamp is provided at the focal point of the first parabolic mirror along the longitudinal direction of the light guide plate. The method of claim 2, And the first and second parabolic mirrors are mirror-coated, or the first and second parabolic mirrors are formed of silver (Ag) or aluminum (Al) metal. The method of claim 2, And a plurality of patterns, such as a fine dot pattern, are printed on the lower surface of the light guide plate. The method of claim 1, The light guide plate is a backlight unit, characterized in that formed of polymethylmethacrylate (PMMA) which is one of the transparent transparent resin material. A liquid crystal display module comprising a backlight unit according to any one of claims 1 to 6, A liquid crystal panel mounted to an upper portion of a backlight unit including a light guide plate mounted inside the fluorescent lamp; A support main frame that borders the backlight unit and the liquid crystal panel; A cover bottom covering a rear surface of the support main; Top cover that borders the front edge of the liquid crystal panel Includes, wherein both sides of the light guide plate in the longitudinal direction is composed of a parabolic mirror.

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