KR101212155B1 - backlight unit - Google Patents

Abstract

The present invention is to provide a backlight unit suitable for alleviating the hot spot phenomenon of the LED lamp by using a lamp housing, thereby eliminating the darkness of the light incident region corresponding to the LED lamp to improve the overall appearance quality. The backlight unit for achieving the same object and the light guide plate; A plurality of LED lamps arranged at a predetermined interval on at least one side of the light guide plate; It includes a lamp housing having a plurality of bent portion in the upper direction on the upper surface corresponding to the area where the light is dark, and configured to surround the LED lamps.

LED, lamp housing

Description

Backlight unit

1 is a perspective view of a backlight unit having a conventional LED

2 is a plan view of a backlight unit using a conventional LED

3 is a plan view showing light distribution when driving a conventional backlight unit;

4 is a perspective view of a backlight unit according to a first embodiment of the present invention;

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

6A and 6B are plan views illustrating the light extension and the overall light distribution by the lamp housing when the backlight unit is driven according to the first embodiment of the present invention.

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

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

9A and 9B are plan views illustrating light concentration and overall light distribution by the lamp housing when the backlight unit is driven according to the second embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

41, 71: LGP 42, 72: LED lamp

43, 73: light scattering means 46, 76: reflector

47, 77: lamp housing 48, 78: PCB board

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, and more particularly, to a backlight unit suitable for improving appearance quality by resolving a dark phenomenon in an incident region between LED lamps.

CRT (Cathode Ray Tube), one of the commonly used display devices, is mainly used for monitors such as TVs, measuring devices, information terminal devices, etc., but the miniaturization of electronic products due to the weight and size of CRT itself It was unable to actively respond to the demand for weight reduction.

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 be replaced. Liquid crystal display (LCD) and gas discharge using electro-optic effects Plasma Display Panel (PDP) and Electro Luminescence Display (ELD) using the electroluminescent effect, among others, are being actively studied for the liquid crystal display device.

In order to replace the CRT, a liquid crystal display device having advantages such as small size, light weight, and low power consumption has recently been developed to be able to perform a sufficient role as a flat panel display device. As used in monitors and large information display devices, the demand for liquid crystal display devices continues to increase.

The liquid crystal display may be classified into a liquid crystal panel displaying an image and a driving unit for applying a driving signal to the liquid crystal panel. The liquid crystal panel may include first and second glass substrates bonded to each other with a predetermined space, and It consists of the liquid crystal layer injected between the 1st, 2nd glass substrate.

The first glass substrate (TFT array substrate) may include a plurality of gate lines arranged in one direction at a predetermined interval, a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate lines, A plurality of pixel electrodes formed in a matrix form in each pixel region defined by crossing a gate line and a data line, and a plurality of thin films which are switched by signals of the gate line to transfer the signal of the data line to each pixel electrode Transistors are formed.

The second glass substrate (color filter substrate) includes a black matrix layer for blocking light in portions other than the pixel region, an R, G and B color filter layer for expressing color colors, and a common electrode for implementing an image. Is formed.

The first and second glass substrates are bonded to each other by a seal material having a predetermined space by a spacer and having a liquid crystal injection hole, so that the liquid crystal is injected between the two substrates.

On the other hand, since most of the liquid crystal display devices are light-receiving elements that display an image by controlling the amount of light source coming from the outside, a separate light source for illuminating the liquid crystal panel, that is, a backlight unit, is necessary. The unit is divided into the edge method and the direct method according to the position where the lamp unit is installed.

The light source may be an EL (Electro Luminescence), an LED (Light Emitting Diode), a CCFL (Cold Cathode Fluorescent Lamp), a HCFL (Hot Cathode Fluorescent Lamp), an external electrode light emitting lamp (EEFL) and the like.

In the above, CCFL, HCFL, and EEFL are used to represent line light sources and surface light sources, and LEDs can be used to represent point light sources.

In addition, the backlight unit has been used as a function for reading information displayed on the screen of the liquid crystal display in a dark place, but recently, the light guide plate has been formed thinner due to various requirements such as design, low power consumption, and thinning. In addition to a function capable of expressing various colors, technology development for reducing power consumption by using the LED (Light Emitting Diode) has been made.

The LED is a solid-state device using a photoelectric conversion effect of a semiconductor, a semiconductor device that emits light when a forward voltage is applied, and emits light at a lower voltage than a lamp using tungsten filament, the filament is not heated and shining, but electrons recombine with holes Since it emits light due to the difference in energy, it has been widely used in various display devices for a long time.

By using the LED as a light source for illuminating the liquid crystal panel, it is possible to easily achieve low power consumption and miniaturization of electronic devices such as a notebook PC.

In addition, since a DC voltage of about V is required to emit LEDs, a DA-AC converter is not required, and thus a driving device is simple and power consumption can be greatly reduced.

Moreover, since LED is a semiconductor element, it is more reliable than a cathode ray tube, and is small and long life.

Hereinafter, a conventional backlight unit will be described with reference to the accompanying drawings.

1 is a perspective view illustrating a backlight unit using a conventional LED, FIG. 2 is a plan view of a backlight unit using a conventional LED, and FIG. 3 is a plan view illustrating light distribution when driving the conventional backlight unit.

As shown in FIG. 1 and FIG. 2, a conventional backlight unit having LEDs includes a light guide plate 20 formed on the rear surface of the liquid crystal panel 10 and a plurality of LED lamps provided on one side of the light guide plate 20. 21, a lamp housing 24 surrounding the LED lamps 21, and a reflector 22 disposed on a lower surface of the light guide plate 20.

The lamp housing 24 configured to surround the LED lamps 21 has a reflective characteristic and is configured to surround the LED lamps 21 as a whole except for one side from which light is emitted. Reference numeral '23' is a PCB board for supporting the LED lamp 21.

The lamp housing 24 surrounding the LED lamps 21 is configured as an upper surface, a lower surface parallel to the upper surface, and a side surface vertically connecting the upper and lower surfaces. That is, the upper surface and the side forms 90 °, and the lower surface and the side forms 90 °. In addition, the LED lamps 21 are disposed at the center of the upper and lower surfaces so as to face the light incident surface of the light guide plate 20. As a result, the light emitted from the LED lamp 21 is strongly advanced in the light incident surface direction, that is, in the horizontal direction.

As described above, the LED light source is composed of a plurality of LED lamps 21 arranged one-dimensionally, wherein the LED lamps 21 sequentially red LED, green LED, blue LED on the PCB substrate It may be arranged, or may be arranged in white LEDs.

When the backlight unit configured as described above implements an image on the liquid crystal panel 10, each of the LED lamps 21 constituting the LED light source is turned on, and the light generated by the LED lamp 21 is light guide plate 20. Scattering therein is transmitted to the back of the liquid crystal panel 10.

At this time, when the LED lamps 21 disposed at the center portion of the lamp housing 24 emit light (ON state), as shown in FIG. 3, light is uniformly provided between the LED lamps 21. It is not delivered. That is, strong light is transmitted to the light incident surface of the light guide plate 20 only at the portion where the LED lamp 21 is positioned, and light transmission is not well performed therebetween.

The conventional backlight unit configured as described above has the following problems.

Since the LED lamps 21 are point light sources, the light distribution of the LED lamps 21 is inferior to that of CCFLs or EEFLs. In particular, since the LED lamp is a point light source in which light propagation to the left and the right is unfavorable, strong light is transmitted only to a portion adjacent to the portion where the LED lamp 21 is located, and light is not transmitted well to other portions. An area occurs. This causes a problem of poor appearance of the backlight unit.

The present invention has been made to solve the above problems, an object of the present invention is to alleviate the hot spot phenomenon of the LED lamp by using a lamp housing, thereby eliminating the darkness of the light incident region corresponding to the LED lamp It is to provide a backlight unit suitable for improving the overall appearance quality.

A backlight unit according to an embodiment of the present invention for achieving the above object is a light guide plate; A plurality of LED lamps arranged at a predetermined interval on at least one side of the light guide plate; It characterized in that it comprises a lamp housing having a portion extending in the direction of the light incident surface of the light guide plate on the upper surface corresponding to the dark visible region, and configured to surround the LED lamps.

A plurality of extended portions formed on the upper surface of the lamp housing is characterized in that formed between the LED lamps.

The extended portion of the upper surface of the lamp housing is characterized in that it comprises a round semi-circle, square, triangular or other shapes that can extend the light.

In another embodiment, a backlight unit includes: a light guide plate; A plurality of LED lamps arranged at a predetermined interval on at least one side of the light guide plate; It characterized in that it comprises a lamp housing configured to have a plurality of bent in the upper direction on the upper surface corresponding to the area where the light is dark, and to surround the LED lamps.

A plurality of curved portions formed on the upper surface of the lamp housing is formed between the LED lamps.

The curved portion of the upper surface of the lamp housing is characterized in that it is composed of an arcuate round roof shape.

The lamp housing is characterized in that it is composed of a reflective material.

The backlight unit may further include a reflecting plate on a lower surface of the light guide plate and light scattering means on an upper portion of the light guide plate.

The light scattering means is characterized by consisting of a plurality of diffusion sheet (Diffusion sheet), a diffusion plate (Diffusion plate) and a prism sheet.

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

First Embodiment

4 is a perspective view of a backlight unit according to a first embodiment of the present invention, FIG. 5 is a plan view of a backlight unit according to a first embodiment of the present invention, and FIGS. 6A and 6B are diagrams illustrating a first embodiment of the present invention. According to the driving of the backlight unit is a plan view showing the light extension and overall light distribution by the lamp housing.

As shown in FIGS. 4 and 5, the backlight unit according to the first embodiment of the present invention is a light guide plate 41 having a predetermined thickness for guiding light and a light incident surface of the light guide plate 41. A plurality of LED lamps 42 arranged at regular intervals on a side surface, a light scattering means 43 provided on an upper surface of the light guide plate 41, a reflecting plate 46 formed on a lower surface of the light guide plate 41, It is configured to include a lamp housing 47 surrounding the LED lamps 42 to extend in the direction of the light incident surface of the light guide plate 41 in the various areas of the upper surface.

In the above, the plurality of extended portions formed on the upper surface of the lamp housing 47 is a region where the light of the LED lamp 42 is not transmitted well, which is dark, that is, the LED lamp 42 in which the LED lamp 42 is not disposed. It is formed between them.

The lamp housing 47 is made of a reflective material so that all of the light generated from the LED lamp 42 is not transmitted to the light incident surface of the light guide plate 41 to be transmitted to the light incident region of the light guide plate 41.

Reference numeral 48 denotes a PCB substrate for supporting the LED lamp 42.

In addition, the extended portion of the upper surface of the lamp housing 47 may be formed to have a round semicircle, a square, a triangle, or any other shape capable of extending light.

In FIG. 6A, an example in which the extended portion of the upper surface of the lamp housing 47 is a round semi-circle shape is illustrated. In this way, when the upper surface of the lamp housing 47 extends in a round semi-circle shape, light is incident on the light guide plate 41. And the light generated from the LED lamp 42 extends into the dark areas between the LED lamps 42 to compensate for the dark areas.

In detail, the LED lamp 42 is a point light source and exhibits a hot spot characteristic in a region where light is generated. That is, the peripheral area appears relatively dark due to the phenomenon that the portion of the LED lamp 42 is brighter than the peripheral area, so that the dark phenomenon occurs in the light receiving area between the LED lamps 42 when viewed in the light receiving area of the light guide plate 41. Occurs.

In order to solve this problem, the present invention is formed by extending the upper surface of the lamp housing 47 corresponding to the region where the light is relatively dark, in particular, the region between the LED lamps 42. That is, the lamp housing 47 corresponding to the LED lamp 42 has a short length so that the light exits early, whereas the lamp housing 47 corresponding to the LED lamp 42 extends through the upper surface extending to the lamp housing 47 corresponding to the LED lamps 42. The dark region is compensated by extending in the light incident region direction.

When the light extends to the dark region between the LED lamps 42 as described above, as shown in FIGS. 6A and 6B, the hot spot area in the area of the LED lamps 42 is alleviated. As a result, the light incident region can exhibit uniform light emission characteristics (light distribution) as a whole.

The extended portion of the lamp housing 47 can be formed by a simple cutting process, it can be designed without further variation in thickness.

The light scattering means 43 is a plurality of diffusion sheets (Diffusion) on the upper surface of the light guide plate 41 in order to provide a light source having a uniform distribution of brightness as a whole light emitted from the LED lamp 42 on the display surface of the liquid crystal panel sheet, diffusion plate and prism sheet.

The reflector 46 is provided to maximize light utilization efficiency by intensively irradiating the light generated by the LED lamp 42 to the display unit of a liquid crystal panel (not shown).

In addition, although the configuration of the backlight unit in which the LED lamps are arranged on one side of the LGP is described above, the LED housing is arranged on both sides of the LGP, and a lamp housing corresponding to a relatively dark area between the LED lamps arranged on both sides is provided. It can also be formed by extending the upper surface of the.

The edge type backlight unit configured as described above condenses the light emitted from the LED lamp 42 to the light incident surface of the light guide plate 41, and then sequentially passes through the light scattering means 43 through the light guide plate 41 to the liquid crystal panel. To pass.

Meanwhile, the backlight unit of the present invention may be used as a light source at the rear or front of various display devices including a liquid crystal display device, and may be used as a light emitting device as it is.

Second Embodiment

7 is a perspective view of a backlight unit according to a second embodiment of the present invention, FIG. 8 is a plan view of a backlight unit according to a second embodiment of the present invention, and FIGS. 9A and 9B are diagrams illustrating a second embodiment of the present invention. FIG. 2 is a plan view illustrating light concentration and overall light distribution by the lamp housing when the backlight unit is driven.

As shown in FIGS. 7 and 8, the backlight unit according to the second embodiment of the present invention is a light guide plate 71 having a predetermined thickness for guiding light and a light incident surface of the light guide plate 71. A plurality of LED lamps 72 arranged at regular intervals on a side surface, a light scattering means 73 provided on an upper surface of the light guide plate 71, a reflecting plate 76 formed on a lower surface of the light guide plate 71, It is configured to include a lamp housing 77 surrounding the LED lamps 72 to be bent upward in various areas of the upper surface.

The lamp housing 77 is made of a reflective material so that all of the light generated from the LED lamp 72 can be transmitted to the light incident region of the light guide plate 71.

Reference numeral '78' is a PCB substrate that supports the LED lamp 72.

The plurality of curved portions formed on the upper surface of the lamp housing 77 is formed between the portions where the light appears dark, for example, between the LED lamps 72 in which the LED lamps 72 are not disposed.

And the curved part of the upper surface of the lamp housing 77 is comprised so that it may become an arcuate round roof shape.

As such, when the upper surface of the lamp housing 77 between the LED lamps 72 is formed in an arcuate shape, as shown in FIG. 9A, the surrounding light (light of the LED lamp 42) is concentrated in this portion. To augment the light into the dark areas between the LED lamps 72.

In detail, the LED lamp 72 is a point light source and exhibits a hot spot characteristic in a region where light is generated. That is, the peripheral area appears relatively dark due to the phenomenon that the portion of the LED lamp 72 is brighter than the surrounding area, so that the dark phenomenon occurs in the light receiving area between the LED lamps 72 when viewed in the light receiving area of the light guide plate 71. Occurs.

In order to solve this problem, the present invention has formed an arcuate convex upper surface of the lamp housing 77 corresponding to the region where the light is relatively dark, in particular, the region between the LED lamp 72. That is, the light of the LED lamp 72 is distributed to the arcuate roof of the lamp housing 77 corresponding to the LED lamps 72 to alleviate the hot spot characteristic in the area of the LED lamp 72, Dark areas are compensated for.

When light is compensated for in the dark region between the LED lamps 72 as described above, as shown in FIGS. 9A and 9B, the light incident region may exhibit uniform light emission characteristics (light distribution) as a whole.

The light scattering means 73 is a plurality of diffusion sheets (Diffusion) on the upper surface of the light guide plate 71 in order to provide a light source with a uniform distribution of light as a whole generated by the light emitted from the LED lamp 72 on the display surface of the liquid crystal panel sheet, diffusion plate and prism sheet.

The reflector 76 is provided to maximize the light utilization efficiency by intensively irradiating the light generated by the LED lamp 72 to the display unit of the liquid crystal panel (not shown).

In addition, although the configuration of the backlight unit in which the LED lamps are arranged on one side of the LGP is described above, the LED housing is arranged on both sides of the LGP, and a lamp housing corresponding to a relatively dark area between the LED lamps arranged on both sides is provided. It is also possible to form the upper surface of the arcuate convex.

The edge type backlight unit configured as described above condenses the light emitted from the LED lamp 72 to the light incident surface of the light guide plate 71, and sequentially passes through the light scattering means 43 through the light guide plate 41 to the liquid crystal panel. To pass.

Meanwhile, the backlight unit of the present invention may be used as a light source at the rear or front of various display devices including a liquid crystal display device, and may be used as a light emitting device as it is.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit of the 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 backlight unit according to the present invention as described above has the following effects.

By extending or reinforcing the light by changing the shape of the lamp housing corresponding to the relatively dark areas, in particular, between the LED lamps, the hot spot phenomenon of the LED lamps can be alleviated so as to exhibit uniform light emission characteristics as a whole.

Thereby, the external appearance quality of a backlight unit can be improved.

Claims (9)

delete delete delete A light guide plate; A plurality of LED lamps arranged at a predetermined interval on at least one side of the light guide plate; And a lamp housing configured to have a plurality of curved portions in an upward direction on an upper surface corresponding to an area where light is dark, and include a lamp housing configured to surround the LED lamps. 5. The method of claim 4, And a plurality of curved portions formed on an upper surface of the lamp housing are formed between the LED lamps. 5. The method of claim 4, And a curved portion of the upper surface of the lamp housing is formed in an arcuate round roof shape. 5. The method of claim 4, And the lamp housing is made of a reflective material. 5. The method of claim 4, The backlight unit may include a reflector on a bottom surface of the light guide plate, The backlight unit, characterized in that the light scattering means is further provided on the light guide plate. 9. The method of claim 8, The light scattering means is a backlight unit, characterized in that consisting of a plurality of diffusion sheet (Diffusion sheet), a diffusion plate (Diffusion plate) and a prism sheet.

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