KR20060077796A - Light emitting diode package and display device having the same - Google Patents

Abstract

Disclosed is a light emitting package or a display device having the same, in which light emitted from a light source is uniformly emitted. And a lens including a light emitting diode, a reflective surface on which light propagating from the light emitting diode is reflected, a refractive surface refracting the reflected light or light traveling on the light emitting diode, and a light path changing layer formed on the reflective surface, The light path changing layer uses a material larger than the refractive index of the lens. This increases the difference in refractive index between the air and the lens so that the light is reflected into the lens, thereby providing a light emitting package having a small amount of light emitted through the reflecting surface.

Display, Light Emitting Diode, Lens, Light Path Change

Description

LIGHT EMITTING DIODE PACKAGE AND DISPLAY DEVICE HAVING THE SAME}

1 is a side view of a light emitting package (LED PACKAGE) according to an embodiment of the present invention.

FIG. 2 is a view of a cross section of the LED package of FIG. 1.

3 is a perspective view of a backlight structure according to an embodiment of the present invention.

4 is a cross-sectional view of a portion of the backlight structure of FIG. 3.

5 is a perspective view of a liquid crystal display according to an exemplary embodiment of the present invention.

The present invention relates to a light source for a display device. More particularly, the present invention relates to a light source for a display device with improved luminance uniformity.

Display devices used for computer monitors and TVs include electroluminescence (EL), vacuum fluorescent display (VFD), field emission display (FED) and plasma display (plasma display). panels, PDPs) and the like, and liquid crystal displays (LCDs) that require a separate light source and do not emit light by themselves.                         

A general liquid crystal display device includes two display panels provided with a field generating electrode and a liquid crystal layer having dielectric anisotropy interposed therebetween. A voltage is applied to the field generating electrode to generate an electric field in the liquid crystal layer, and the voltage is changed to adjust the intensity of the electric field, thereby adjusting the transmittance of light passing through the liquid crystal layer to obtain a desired image.

In this case, the light may be provided by an artificial light source provided separately or may be natural light.

Artificial light sources for liquid crystal displays, or back light devices, use multiple fluorescent lamps, such as cold cathode fluorescent lamps (CCFL) or external electrode fluorescent (EEFL), or multiple light emitting diodes as light sources. do.

Since the dual light emitting diodes do not use mercury, they are environmentally friendly, mechanically stable, have long lifespan, and have excellent color reproducibility.

Such a light emitting diode emits light in the form of a point light source, and in the case of applying it as a surface light source, developments such as employing a lens structure that emits light to the side have been in progress. However, even a lens structure that emits side light cannot block the light directed directly to the entire surface, thereby inhibiting uniform distribution of light. In order to secure uniformity, a method of forming a pattern or attaching a reflective material to one surface of a light guide plate disposed on a light emitting lens has been proposed. In this method, as the size of the backlight device increases, precision of pattern printing and alignment miss with the light emitting package are caused, which eventually affects light uniformity.

An object of the present invention is to provide a light emitting package in which light is evenly distributed in a backlight using a light emitting diode (LED) as a light source.

Another object of the present invention is to provide a display device using the light emitting package as a light source.

The light emitting package for achieving the above object of the present invention includes a light source, a bottom surface disposed on the light source, a first outer surface extending from the bottom surface, and a second outer surface extending from the first outer surface. And a lens having an outer central surface extending from the second outer surface and forming a conical groove, and an optical path changing layer formed on the outer central surface.

The optical path changing layer has a refractive index different from that of the lens, and when the refractive index of the lens is n1 and the refractive index of the optical path changing layer is n2, n1 <n2 is preferable.

In addition, the light path changing layer is preferably made of a poly ethlyelene terephthalate (PET) material.

The light emitting package may include a light emitting diode as a light source.

A part of the light incident on the outer central plane proceeding from the light emitting diode is reflected from the outer central plane to the second outer surface and refracted by the second outer surface, or reflected

A part of the light incident on the outer central plane is refracted by the light path changing layer, reflected from the upper surface of the light path changing layer, and proceeds into the lens.

That is, the outer surface of the lens in contact with the air has a structure including both the refractive surface and the reflective surface.

Here, the amount of light passing through the light path changing layer is preferably less than 10% of the light generated from the light source, 2 to 3%.

According to another aspect of the present invention, there is provided a display device including a light emitting diode, a reflecting surface on which light propagating from the light emitting diode is reflected, and a reflecting surface on which the reflected light or light propagating from the foot and diode is refracted And a light emitting package including a light path changing layer formed on the reflective surface, and a display panel displaying an image using light passing through the light emitting package.

DETAILED DESCRIPTION Embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, area, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle.

1 is a side view of a light emitting package according to an embodiment of the present invention, Figure 2 is a cross-sectional view of the light emitting package of FIG. 2 is a view for explaining an optical path in the light emitting package according to the present invention, a partial cross-sectional view of the light emitting package of FIG.

Referring to FIG. 1, the light emitting package 344 includes a support 13, a light scattering lens 10, and an optical path changing layer 30.

The light scattering lens 10 includes a first portion 11 and a second portion 12.

The first portion 11 has a hemispherical or semi-elliptic shape and a conical groove 15 having the same central axis as the hemisphere or semi-ellipse is formed into a base of the hemisphere or semi-ellipse, and the second portion 12 ) Has a shape in which the cone from which the vertices are cut out is inverted (hereinafter referred to as an inverted cone), and the groove of the inverted cone 16 has the same central axis as that of the inverted cone whose corner is cut out from the top surface thereof. It is formed in the form.

The second part 12 is disposed on the first part 11 so as to coincide with the central axis, and these two parts are integrally formed.

The material constituting the light scattering lens 10 is a material having a refractive index of about 1.5, and may be made of polymethyl mata acrylate (PMMA) or cyclic olefin copolymer (COC).

The light path changing layer 30 is formed in the groove 16 of the second portion of the light scattering lens 10.

The light path changing layer 30 is a material having a larger refractive index than the light scattering lens 10, and preferably has a refractive index of 1.7 to 2.0. In this case, the light path changing layer 30 may serve as an auxiliary lens to scatter light incident from the light scattering lens 10. In addition, the light path changing layer 30 may serve as an auxiliary lens for condensing light incident from the light scattering lens 10.

In addition, it is preferable to use PET (poly-etylene-terephthalate) as a material satisfying such refractive index.

The light path changing layer 30 is formed to fill the groove 16 of the second portion of the light scattering lens 10, but may be formed integrally with the light scattering lens.

In the drawing, all of the grooves 16 are formed to fill the shape, but the shape of enclosing the outer surface of the grooves 16 may be possible, and a prism pattern may be formed on the outer surface of the light path changing layer 30.

The support 13 has a light emitting diode chip (not shown, hereinafter referred to as a light emitting diode) mounted thereon, and lead wires 17 and 18 for applying power to the chip are formed.

Referring to FIG. 2, a path in which light travels in the light emitting package including the light path changing layer will be described.

The light scattering lens 10 has a bottom surface 45, an elliptical outer surface 41 extending from the bottom 45, an inverted conical outer surface 42 extending from the elliptic outer surface 41, and an inverted conical outer surface. It consists of an outer central plane 46 which forms an elongated conical groove.

In addition, the outer surface 40 of the lens 10 serves as a refractive surface, and the outer central surface 46 serves as a total reflection surface.                     

Light emitted from a light emitting diode (not shown) is largely divided into light reaching the outer side and light reaching the outer center side. Light that is refracted by the outer surface and emitted is defined as side light, and light emitted from the outer central surface is called vertical light.

Part of the light reaching the outer central plane proceeds inside the lens 10 in a straight line direction and is totally reflected at the conical outer central plane 46 to travel toward the outer surface 40, and the light reaching the outer surface 40 is transmitted to the outer surface ( It is refracted by 40 and exits the lens 10.

The light that is not totally reflected among the light reaching the outer central plane 46 is refracted by the light path changing layer 30, and is reflected at the interface where the light path changing layer 30 is in contact with air, and then proceeds back into the lens. By repeating the reflection and refraction such that the light is refracted to the outer surface 40 can reduce the amount of vertical light.

In other words, the light path changing layer 30 serves to recycle the light that is not reflected and refracted by the outer central surface 46 serving as the total reflection surface.

The light path changing layer 30 preferably uses a material having a larger refractive index than the light scattering lens 10.

This is based on the principle that the reflectance of light at an interface between materials having different refractive indices is larger as the difference in refractive index is larger.

For example, when the refractive index of the light scattering lens 10 is 1.5 and the refractive index of the light path changing layer 30 is 1.8, the difference in refractive index between the light path changing layer 30 and air is 0.8 and the light path changing layer is Since the refractive index difference is greater than 0.5 when only the light scattering lens 10 is used without using the 30, a relatively large reflectance can be ensured.                     

The refractive index of the light path changing layer is preferably about 1.7 to 2.0, and it is preferable to use polyethylene terephthalate (PET) as a material having such a refractive index.

By filling the light path changing layer 30, the amount of vertical light of the light emitting package is secured at a level of 1 to 5% of light emitted from the light emitting diode chip.

3 is a backlight assembly according to an embodiment of the present invention.

Since the light emitting package applied to the backlight assembly is the same as the above description, duplicate description thereof will be omitted, and the same reference numerals and names will be used for the same parts. .

Referring to Figure 3, the backlight assembly according to an embodiment of the present invention

The light source body 349, the reflection member 341, the diffusion member 342, the plurality of optical sheets 343, the support member 364, and the light source driver 920 are included.

The light source body 349 includes a printed circuit board 345 and a light emitting package 344.

 The light emitting package 344 may be a white light emitting package that emits white light or a red, green, and blue light emitting package. Alternatively, a red light emitting package or the like may be auxiliary to the white light emitting package.

The light source body 349 includes a light emitting package 344 mounted on one surface of the printed circuit board 345.

4 and 5, the light emitting packages 344 are regularly arranged at regular intervals, but a structure in which a plurality of light emitting packages 344 are arranged in a zigzag manner may also be used.

Although the number of the light source bodies 349 is three, the number may be increased or decreased depending on the required brightness and the screen size of the liquid crystal display.

The diffusion member 342 is disposed on the light source body 349 to mix and diffuse light emitted from the light emitting package 344. The diffusion member is preferably made of PMMA (Poly Methyl Mata Acrylate) in the form of a thick plate.

The plurality of optical sheets 341 are positioned on the diffusion member 342 and include a diffusion sheet or a prism sheet, and serve to diffuse the light diffused from the diffusion member 342 again.

The reflective member 341 has a plurality of holes positioned on the printed circuit board 345 and protruding the light emitting portion of the light emitting package 344, and directs light from the light emitting package 344 to the diffusion member 342. Reflect.

 The supporting member 364 is mounted between the reflecting member 341 and the diffusing member 342 to maintain a constant distance between the light source body 349 and the diffusing member 342, and the diffusing member 342 and the optical sheet 343. Support.

 The support member 364 has a stepped portion for accommodating the diffusion member 342 and the plurality of optical sheets on an upper surface thereof. Here, the support member 364 has a rectangular frame shape, but may be separated into four rod shapes and separately assembled to the storage container 362.

The light source driver 920 controls the current applied to the light source body 349 to blink the current of the light emitting package 344 constituting the light source body and to control the brightness thereof.                     

The storage container 362 accommodates the above-described light source body 349, the support member 364, the diffusion member 342, the light source body 349, the reflective member 341, and the like.

 Referring to FIG. 4, the light paths emitted from the light emitting package will be described in the backlight assembly.

As described above, the light propagating in the light emitting package is largely divided into side light and vertical light. Most of the side light is reflected by Fresnel Reflection on the first surface 142 of the diffusion member, and a large amount of the side light is reflected, and the remaining light enters the diffusion member 342 after refraction and then exits the diffusion member by refraction on the second surface 242. do.

In addition, the side light directed to the reflective member is divided into the light reflected by the Fresnel reflection from the first surface 142 and the refracted light after the reflection from the reflective member 341 and some of the light continues to propagate Is emitted out of the diffusion member 342.

Vertical light (the light incident vertically with an angle of radiation) is first Fresnel Reflection on the first surface 142. This angle has a small radiation angle, so the Fresnel Reflection is relatively small and refracted. And exits mainly out of the diffusion member 342.

This process is an essential process for securing color mixing space and increasing uniformity. The core of the present invention is to apply the light emitting package 344 having a structure that maintains this process and optimizes the amount of vertical light.

5 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention.                     

In this embodiment, the configuration of the light source body 349, the reflection member 341, the diffusion member 342, the plurality of optical sheets 343, the support member 364, the light source driver 920, the storage container 362 is Since the same description as in the above-described embodiment of the backlight assembly will not be repeated, the same reference numerals and names will be used for the same parts.

Referring to FIG. 5, the liquid crystal display 900 according to the exemplary embodiment of the present invention includes a display unit 350, a backlight assembly 340, and a liquid crystal panel 300 for providing light to the display unit 350. A front chassis 361 and a fixing member 363 for fixing to the backlight assembly 340 are included.

The display unit 350 includes a liquid crystal panel assembly 300 for displaying an image, data and gate printed circuit boards 450 and 550 which provide driving signals for driving the liquid crystal panel assembly 300. In this case, the data and gate printed circuit boards 450 and 550 are electrically connected to the liquid crystal panel assembly 300 through a data tape carrier package (TCP) 510 and a gate TCP 410.

The liquid crystal panel assembly 300 is interposed between a thin film transistor (TFT) substrate 100, a color filter substrate 200 coupled to the TFT substrate 712, and the two substrates 100 and 200. A liquid crystal layer (not shown).

The TFT substrate 100 is a transparent glass substrate in which a switching element TFT (not shown) is formed in a matrix form. Data and gate lines are respectively connected to the source and gate terminals of the TFTs, and a pixel electrode (not shown) made of a transparent conductive material is connected to the drain terminal.

The color filter substrate 200 is a substrate in which RGB pixels (not shown) which are color pixels are formed by a thin film process. A common electrode (not shown) made of a transparent conductive material is coated on the front surface of the color filter substrate 200.

A backlight assembly 340 is provided below the display unit 350 having the above configuration to provide uniform light to the display unit 350.

The backlight assembly 340 is mounted below the liquid crystal panel assembly 300 and includes a light source body 349 and an assembly 300 in which a plurality of light emitting diodes 344 are mounted on a printed circuit board (PCB) substrate 345. And a diffusion member 342 and a plurality of optical sheets 343 and a PCB substrate 345 positioned between the light emitting diodes 344 and diffusing light from the light emitting diodes 344 to the assembly 300. And a plurality of holes protruding the light emitting portion of the light emitting package 344, a reflecting member 341 reflecting light from the light emitting package 344 toward the assembly 300, and a reflecting member 341 and a diffusing member 342. And a support member 364 which maintains a distance between the light source body 349 and the diffusion member 342 and supports the diffusion member 342 and the optical sheet 343.

According to the present invention, it is possible to effectively adjust the traveling direction of the light emitted from the light emitting package, so that the mixed color section for making white light and the uniform dispersion section for forming uniform surface light in the backlight for the liquid crystal display device can be reduced. Therefore, it can contribute to the thinning of the liquid crystal display device.

In addition, it is possible to form a reflective pattern on a conventional light guide plate or to secure a uniform light distribution only by manufacturing a light emitting package instead of a reflector attached to a light guide plate, thereby easily aligning with the light guide plate, thereby contributing to manufacturing efficiency.

Claims (14)

Light source; A lens having a bottom surface disposed on the light source, an outer surface extending from the bottom surface, and an outer central surface forming a conical groove extending from the outer surface; And And a light path changing layer formed on the outer central surface, wherein the refractive index of the light path changing layer is larger than the refractive index of the lens. In claim 1, The light path changing layer is a light emitting package consisting of a poly-etylene-terephthalate (PET) material  In claim 1, The light source further includes a light emitting package disposed on a central axis of the lens. In claim 3, The amount of light transmitted from an upper surface of the light path changing layer is less than 5% of the amount of light emitted from the light emitting diode. 4. The lens of claim 3, wherein the outer surface of the lens includes a first outer surface extending from the bottom surface and a second outer surface extending from the first outer surface and formed between the bottom surface and the outer central surface. Luminous package. In claim 5, Light incident on the outer central plane proceeding from the light emitting diode is reflected from the outer central plane to the second outer surface, refracted and emitted from the second outer surface, and the light incident on the first outer surface is A light emitting package that is refracted by the first outer surface and emitted out of the lens The light emitting diode of claim 5, wherein a part of the light traveling from the light emitting diode and incident on the outer center plane is reflected from the outer center plane to the second outer plane, and is refracted and emitted from the second outer plane. The light emitting package is refracted by the light change layer, reflected from the upper surface of the light path change layer, and proceeds into the lens. Light emitting diodes; A lens including a reflective surface on which light propagating from the light emitting diode is reflected, and a refractive surface on which the reflected light or light propagating from the light emitting diode is refracted; And And a light path changing layer formed on the reflective surface, wherein the refractive index of the lens is smaller than that of the light path changing layer. Light source; A lens having a bottom surface disposed on the light source, an outer surface extending from the bottom surface, an outer central surface extending from the outer surface and forming a conical groove; And A light emitting package comprising an auxiliary lens formed on the outer central surface, wherein the refractive index of the lens is smaller than the refractive index of the auxiliary lens. The light emitting package of claim 9, wherein a refractive index of the light path changing layer is 1.7 to 2.0. In claim 9, The light path changing layer is a light emitting package consisting of a poly-etylene-terephthalate (PET) material. A lens comprising a light emitting diode, a reflective surface on which the light traveling from the light emitting diode is reflected, a refractive surface on which the reflected light or the light traveling from the foot and the diode is refracted, formed on the reflective surface and passing through the reflective surface A light emitting package including a light path changing layer for changing a path of light; And And a display panel configured to display an image by using the light passing through the light emitting package. The liquid crystal display of claim 12, wherein a refractive index of the lens is smaller than a refractive index of the light path changing layer. In claim 12, The light path changing layer is a liquid crystal display device composed of a poly-etylene terephthalate (PET) material.

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