KR20070081969A - Led lamp and backlight unit having the same - Google Patents

Abstract

An LED(Light Emitting Diode) lamp and a backlight unit having the same are provided to increase the amount of light advancing in right and left directions of an LED lamp, by forming an optical lens of the LED lamp in a prism shape. An LED lamp comprises an LED chip(42). A cathode lead wire(43a) and an anode lead wire(43b) are respectively connected to both ends of a lower portion of the LED chip. A phosphor substance(44) is formed to wrap the LED chip. An optical lens(45) is formed in a prism shape to wrap the LED chip and the phosphor substance. A reflective frame(46) is formed to surround the LED chip, wherein an inside surface of the reflective frame has an inclination structure.

Description

LED lamp and backlight unit having the same {LED lamp and backlight unit having the same}

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

2 is an enlarged cross-sectional view of a conventional LED.

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

4 is a structural diagram of an LED lamp according to an embodiment of the present invention

5A and 5B are a front view and a plan view of the lens of the LED lamp according to FIG.

6 is another exemplary view of changing the shape of the LED lamp according to the present invention.

7 is a structural perspective view of a backlight unit according to a first embodiment of the present invention having the LED lamp of FIG.

8 is a plan view illustrating light distribution when driving the backlight unit according to the first embodiment of the present invention;

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

Explanation of symbols on the main parts of the drawings

41: PCB substrate 42: LED chip

43a: cathode lead wire 43b: anode lead wire

44 phosphor 45 optical lens

46: reflection frame 70, 90: light guide plate

71, 91: LED lamp 72: reflector

80: liquid crystal panel 91a, 91b: first and second LED lamps

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, and more particularly, to an LED lamp and a backlight unit having the same, which are suitable for improving the luminous efficiency and appearance by changing the shape of the light emitting part of the LED lamp or modifying the arrangement of the LED lamp.

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 been recently developed to be able to perform a sufficient role as a flat panel display device, and not only a monitor of a laptop computer but also a desktop computer. The demand for liquid crystal display devices continues to increase as they are used in monitors and large information display devices.

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, 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 21 on one side of the light guide plate 20. It consists of the LED light source comprised and the reflecting plate 22 arrange | positioned at the lower surface of the said light guide plate 20. As shown in FIG.

Although not shown in the figure, a lamp housing having reflective characteristics is further provided to surround the LED lamps 21 as a whole.

As described above, the LED light source is composed of a plurality of LED lamps 21 arranged in one dimension, 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.

Looking at the inside of the LED lamp 21 in more detail, the LED chip 32, the cathode lead wire 33a and the anode lead wire 33b connected to both ends of the lower portion of the LED chip 32, and the LED chip ( A phosphor 34 formed to enclose 32, an optical lens 35 composed of an LED chip 32 and a shell-shaped curved surface to enclose the phosphor 34, and a periphery of the LED chip 32. It is composed of a surrounding reflective frame 36.

In the LED lamp 21 having the above configuration, the light emitted from the LED chip 32 is focused on the optical lens 35 of the shell type, and as shown in FIG. 2, mostly emits light in the vertical direction.

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 having the above structure emit light (ON state), as shown in FIG. 3, light is not uniformly transmitted between the LED lamps 21. That is, a strong light is transmitted to the portion where the LED lamp 21 is located, and a phenomenon in which light is not transmitted well occurs.

Reference numeral '23' is a PCB substrate on which the LED lamp is mounted, and '30' is a metal substrate.

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

As described above, since the LED lamps 21 are point light sources, the uniformity of the light distribution irradiated onto the liquid crystal panel is inferior to that of the CCFL or EEFL which is the linear light source.

In particular, since the LED lamp has a curved optical lens, strong light is emitted only at the center of the LED chip, and light is not transmitted to the side, resulting in a dark area. 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 change the shape of the light emitting portion of the LED lamp or to modify the arrangement of the LED lamp LED lamp suitable for improving the luminous efficiency and appearance quality and the same It is to provide a backlight unit provided.

LED lamp according to the present invention for achieving the above object is an LED chip; A cathode lead wire and an anode lead wire connected to both lower ends of the LED chip, respectively; A phosphor formed to surround the LED chip; An optical lens formed in a prism shape to surround the LED chip and the phosphor; It is characterized by consisting of a reflective frame configured to surround the LED chip.

The reflective frame surrounds the periphery of the LED chip, characterized in that the inner surface is configured in an inclined structure.

The optical lens has a circular shape, characterized in that it is configured to form a step shape that becomes wider from top to bottom.

The optical lens is characterized in that it further comprises being formed in a step shape symmetrical to form a rectangular shape.

The optical lens is configured in a polygonal shape and is characterized in that it further comprises a stepped shape so that at least both sides of the left and right symmetrical.

In one embodiment, a backlight unit includes: a light guide plate; A plurality of LED lamps in which an optical lens has a prism shape on at least one side of the light guide plate; And a reflecting plate disposed on a lower surface of the light guide plate.

The LED lamp has an LED chip, a cathode lead wire and an anode lead wire respectively connected to the lower ends of the LED chip, a phosphor formed to surround the LED chip, and a prism shape to surround the LED chip and the phosphor. It characterized in that it comprises an optical lens, and a reflective frame configured to surround the periphery of the LED chip.

The optical lens of the LED lamp is characterized in that it is composed of a prism shape of at least the left and right side surface forming a step shape.

The backlight unit according to another embodiment of the present invention is characterized by consisting of a light guide plate and LED lamps arranged obliquely in a shape of a mount (triangle) in pairs of two on the light incident surface side of the light guide plate.

Hereinafter, an LED lamp and a backlight unit having the same according to an exemplary embodiment of the present invention will be described with reference to the accompanying drawings.

4 is a structural diagram of an LED lamp according to an embodiment of the present invention, Figures 5a and 5b is a front view and a plan view of the lens of the LED lamp according to Figure 4, Figure 6 is a modified shape of the LED lamp according to the invention Another illustration is.

First, the configuration of the LED lamp according to the present invention will be described.

4, 5A and 5B, the LED lamp according to the embodiment of the present invention, the LED chip 42, and the cathode lead wire 43a connected to both ends of the lower portion of the LED chip 42, respectively; An anode lead wire 43b, a phosphor 44 formed to surround the LED chip 42, and an optical lens 45 formed in a prism shape along a circumference to surround the LED chip 42 and the phosphor 44 ) And a reflection frame 46 having an inclined structure so as to surround the periphery of the LED chip 42.

The optical lens 45 is formed in a circular shape as a whole, and is configured to form a step shape in which its width becomes wider from top to bottom.

As a result, the LED lamp can improve its luminous efficiency not only in the vertical direction but also in the left and right direction as shown in FIG. 4 through the optical lens 45 in which the light emitted from the LED chip 42 has a prism shape. have.

In this case, as shown in FIG. 6, the optical lens may be formed in a stepped shape that is symmetrical to form a square shape.

Although not shown in the drawings, the optical lens of the LED lamp according to the present invention is configured in a polygonal shape including a circular or rectangular shape as described above and is formed in a staircase shape so that at least both sides of the left and right sides are symmetrical. As such, when the left and right side surfaces have a step shape, the light emission region can be extended not only in the upper direction but also in the left and right sides of the LED lamp. That is, the amount of light propagated to the left and right sides of the LED lamp can be increased.

Next, the configuration of the backlight unit according to the first embodiment of the present invention will be described.

7 is a structural perspective view of a backlight unit according to a first embodiment of the present invention having the LED lamp of FIG. 4, and FIG. 8 is a plan view illustrating light distribution when driving the backlight unit according to the first embodiment of the present invention. .

As shown in FIG. 7, the backlight unit according to the first embodiment of the present invention includes a light guide plate 70 formed on the rear surface of the liquid crystal panel 80 and a plurality of LED lamps 71 on one side of the light guide plate 70. LED light source and a reflector 72 disposed on the lower surface of the light guide plate 70.

Although not shown in the figure, a lamp housing having reflective characteristics is further provided to surround the LED lamps 71 as a whole.

As described above, the LED light source is composed of a plurality of LED lamps 71 arranged in one dimension, wherein the LED lamps 71 are a combination of red LED, green LED, blue LED on the PCB substrate It may be arranged, or may be arranged in white LEDs.

Looking at the inside of the LED lamp 71 in more detail, the LED chip 42, the cathode lead wire 43a and the anode lead wire 43b connected to the lower ends of the LED chip 42, respectively, and the LED chip ( A phosphor 44 formed to surround 42, an optical lens 45 formed in a prism shape along a circumference to surround the LED chip 42 and the phosphor 44, and the periphery of the LED chip 42 Consists of a reflective frame 46 configured to be inclined to surround the.

Since the LED lamp 71 having the above configuration is configured in a prism shape in which at least the left and right sides of the optical lens 45 have a step shape, the light emitted from the LED chip 42 emits most of the light in the vertical direction, that is, the upper direction. Instead, the amount of light emitted in the left and right directions is increased.

As a result, the light emitted from the LED lamp 71 emits not only the LED lamps 71 but also the dark areas between the LED lamps 71 to compensate for the dark areas.

That is, the light emitted from the LED lamp 71 may be evenly transmitted to the light incident surface of the light guide plate 70.

In detail, the LED lamp 71 is used as a point light source, and exhibits a hot spot characteristic in a region where light is generated. That is, the peripheral region appears relatively dark because the LED lamp 71 portion is brighter than the peripheral region, so that when viewed from the light incident surface side of the light guide plate 70, it is dark in the incident region between the LED lamps 71. This happens.

In order to solve this problem, the LED lamp 71 is formed in a prism shape to increase the amount of light traveling in the left and right directions so that dark areas between the LED lamps 71 are compensated for.

When the LED lamp 71 is configured in this way, as shown in FIG. 8, the light incident region of the light guide plate 70 is improved compared to the conventional light spot, thereby exhibiting a uniform luminance as a whole.

When the backlight unit configured as described above implements an image on the liquid crystal panel 80, each of the LED lamps 71 constituting the LED light source is turned on, and the light generated by the LED lamp 71 is light guide plate 70. Scattering therein is transmitted to the rear surface of the liquid crystal panel 80.

The reflector 72 is provided to maximize the light utilization efficiency by intensively irradiating the light generated by the LED lamp 71 to the display unit of the liquid crystal panel (not shown).

Light scattering means (not shown) may be further provided between the light guide plate 70 and the liquid crystal panel 80. The light scattering means includes a plurality of diffusion sheets and diffusion sheets on the upper surface of the light guide plate 70 in order to provide a light source having a uniform distribution of light on the display surface of the liquid crystal panel. It consists of a plate (Diffusion plate) and a prism sheet.

Although the backlight unit having the above configuration is not shown in the drawing, the lamp housing further includes a lamp housing so as to surround the LED lamp 71 as a whole, and the light generated from the LED lamp 71 has the light guide plate 70. It is made of reflective material so that it can be delivered to the light-receiving surface.

Reference numeral 41 denotes a PCB substrate for supporting the LED lamp 71.

In the above description, the edge type backlight unit in which the LED lamps are arranged on one side of the LGP is described, but the LED lamps may be arranged on both sides of the LGP.

Next, the configuration of the backlight unit according to the second embodiment of the present invention will be described.

9 is a plan view illustrating a backlight unit according to a second embodiment of the present invention.

The backlight unit according to the second exemplary embodiment of the present invention compensates for a dark area between the LED lamps according to the hot spot characteristic of the LED lamp 91, and as shown in FIG. 9, the light guide plate 90 and The light guide plate 90 includes two pairs of LED lamps 91a and 91b arranged obliquely in a mount shape in pairs of two on the light receiving surface side.

As described above, when the paired first and second LED lamps 91a and 91b are arranged obliquely in a triangle, the amount of light transmission between the LED lamps 91 may be increased rather than when arranged in a line.

This makes it possible to uniformly transmit light to the light incident surface of the light guide plate 90 to compensate for dark areas between the LED lamps.

 In detail, the LED lamp 91 is used as a point light source, and hot spots are exhibited by the strong generation of light in an upward direction. That is, the peripheral region appears relatively dark because the LED lamp 91 portion is brighter than the peripheral region, so that when viewed from the light incident surface side of the light guide plate 90, the dark phenomenon occurs in the light incident region between the LED lamps 91. This happens.

In order to solve the problem, the present invention compensates for the dark area by arranging obliquely in a triangular shape so that two LED lamps are paired so that light travels in the left and right directions of the LED lamp.

A reflector may be disposed on a lower surface of the light guide plate 90 of the backlight unit according to the second embodiment, and light scattering means may be further provided on the upper surface of the light guide plate.

On the other hand, the backlight unit according to the first and second 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. .

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

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

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

First, by forming at least the left and right side surfaces of the optical lens of the LED lamp in a prism shape, the amount of light traveling in the left and right directions of the LED lamp can be increased.

Second, by forming at least the left and right side surfaces of the optical lens of the LED lamp in a prism shape, it is possible to improve the appearance quality by improving the dark phenomenon of the light incident portion of the light guide plate corresponding to the LED lamp.

Third, by arranging two LED lamps diagonally in a pair of triangles, it is possible to improve the appearance quality by improving the dark phenomenon of the light incident portion of the light guide plate corresponding to the LED lamps.

Claims (9)

LED chip; A cathode lead wire and an anode lead wire connected to both lower ends of the LED chip, respectively; A phosphor formed to surround the LED chip; An optical lens formed in a prism shape to surround the LED chip and the phosphor; LED lamp, characterized in that consisting of a reflective frame configured to surround the LED chip. The method of claim 1, The reflecting frame is a LED lamp, characterized in that the inner surface is formed in an inclined structure surrounding the periphery of the LED chip. The method of claim 1, The optical lens has a circular LED lamp, characterized in that the configuration is configured to form a step of widening from the top to the bottom. The method of claim 1, The optical lens is a LED lamp, characterized in that it further comprises formed in a step-like symmetrical square shape. The method of claim 1, The optical lens has a polygonal shape and LED lamp, characterized in that further formed in a staircase shape so that at least both sides of the left and right symmetrical. A light guide plate; A plurality of LED lamps in which an optical lens has a prism shape on at least one side of the light guide plate; And a reflector disposed on a bottom surface of the light guide plate. The method of claim 6, The LED lamp is an LED chip, A cathode lead wire and an anode lead wire respectively connected to both lower ends of the LED chip; Phosphor formed to surround the LED chip (phosphor), An optical lens formed in a prism shape to surround the LED chip and the phosphor; And a reflective frame configured to surround the periphery of the LED chip. The method of claim 6, And the optical lens of the LED lamp is formed in a prism shape in which at least left and right side surfaces form a step shape. The light guide plate, And a pair of LED lamps arranged obliquely in a shape of a mount (triangle) in pairs of two on the light receiving surface side of the light guide plate.

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