Light emitting apparatus and surface light source apparatus having the same

Provided are a light emitting apparatus and a surface light source apparatus having the same. The light emitting apparatus comprises a package body, a first color light emitting part in a first cavity of the package body, and a second color light emitting part in a second cavity of the package body. The package body comprises a plurality of cavities.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119 to Korean Patent Application No. 10-2007-0060930 (filed on Jun. 21, 2007), which is hereby incorporated by reference in its entirety.

BACKGROUND

Nitride semiconductors in III-V groups are variously applied to a light device such as blue/green light emitting diodes (LEDs), a high speed switching device such as a metal oxide semiconductor field effect transistor (MOSFET) and a hetero junction field effect transistor (HEMT), and a light source of a lighting unit and a display device.

SUMMARY

Embodiments provide a light emitting apparatus that can realize a white light emitting part and a green light emitting part in one package, and a surface light source apparatus having the same.

Embodiments provide a light emitting apparatus that operates in cooperation with an external apparatus to illuminate white light and/or green light in the form of surface light, and a surface light source apparatus having the same.

An embodiment provides a light emitting apparatus comprising: a package body comprising a plurality of cavities; a first color light emitting part in a first cavity of the package body; and a second color light emitting part in a second cavity of the package body.

An embodiment provides a surface light source apparatus comprising: a light emitting unit comprising at least one light emitting apparatus comprising a first color light emitting part in a first cavity of a package body, and a second color light emitting part in a second cavity of the package body; and a surface light source unit one side of the light emitting unit, the surface light source unit illuminating light incident from the first color light emitting part and the second color light emitting part in a form of surface light.

An embodiment provides a surface light source apparatus comprising: a light emitting unit comprising at least one light emitting apparatus comprising a first color light emitting part in a first cavity of a package body, and a second color light emitting part in a second cavity of the package body, and a substrate to which the light emitting apparatus is electrically connected; a driving control circuit selectively controlling driving of the first color light emitting part and the second color light emitting part as a door is opened; and a surface light source unit one side of the light emitting apparatus, the surface light source unit illuminating light incident from the first color light emitting part and the second color light emitting part in a form of surface light.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1is a front view of a light emitting apparatus according to a first embodiment,FIG. 2is a cross-sectional view ofFIG. 1taken along a line A-A, andFIG. 3is a cross-sectional view ofFIG. 1taken along a line B-B.

Referring toFIG. 1, the light emitting apparatus100comprises a package body110, a first color light emitting part120, and a second color light emitting part130.

The package body110can be formed in a silicon-based wafer level package (WLP), Also, the package body110can be formed in one of a ceramic type substrate, a printed circuit board (PCB) type substrate, and a lead frame type substrate using materials such as a bismaleimide-triazine (BT)-resin and an FR-4. Also, the package body110can be formed in a single layer substrate or a multi-layered substrate. There is no limitation for a material of the package body110.

The package body110comprises a first cavity121and a second cavity131. The first color light emitting part120can be realized in the first cavity121, and the second color light emitting part130can be realized in the second cavity131. The first cavity121and the second cavity131can be arranged in a vertical direction or a horizontal direction in the upper surface of the package body110. The locations of the first and second cavities121and131can change.

The first and second cavities121and131of the package body110are divided by a divider116.

The first and second cavities121and131can be formed in a cup shape or a bathtub shape to have a predetermined depth on the upper surface of the package body110. The surface shapes of the first and second cavities121and131can be a square or a rectangle, and are not limited thereto.

Lateral sides122and132of the first and second cavities121and131can be formed slope. The lateral sides122and132are inclined at a predetermined angle (for example, about 120°) with respect to the bottom of the cavities, respectively, to reflect incident light.

First to fourth electrodes141,142,143, and144are formed on the surface of the package body110. The first and second electrodes141and142extend from the bottom of the first cavity121up to the upper side, the lateral sides, and a portion of the rear side of the package body110. The first and second electrodes141and142are electrically open by a first dielectric part123formed in the first cavity121. The first to fourth electrodes141,142,143, and144can be formed by a plating method. First dielectric part123may separate first and second electrodes141and142via an angle so as to have a first portion closer to the first electrode141than second electrode142, and an opposite second portion closer to the second electrode142than first electrode141.

The third and fourth electrodes143and144extend from the bottom of the second cavity131up to the upper side, the lateral sides, and the rear side of the package body110. The third and fourth electrodes143and144are electrically separated by a second dielectric part133formed in the second cavity131. Second dielectric part133may separate third and fourth electrodes143and144via an angle so as to have a first portion closer to the third electrode143than fourth electrode144, and an opposite second portion closer to the fourth electrode144than third electrode143.

Referring toFIGS. 1 and 2, the first color light emitting part120is realized in the first cavity121, and comprises first light emitting diodes (LEDs)126and a first resin material128, and emits first color light.

The first LEDs126comprises at least one blue LED. The first LED126is attached on the first electrode141or the second electrode142located at the first cavity121, and is electrically connected to the first electrode141and the second electrode142using wires127.

The first resin material128is formed in the first cavity121, and can be formed of a resin material such as transparent epoxy and silicon, and comprises a phosphor129therein. The phosphor129absorbs a portion of blue light from the first LEDs126to emit yellow light, and can comprise YAG or silicate-based yellow phosphor, for example. The first color light emitting part120emits white light by mixing blue light from the first LEDs126with yellow light emitted from the phosphor129.

For another example of the first color light emitting part120, the first LEDs126can comprise a red LED, a green LED, and a blue LED. In this case, the first color light emitting part120can emit white light using these three color LEDs. In this case, phosphor do not need to be added to the first resin material128.

For still another example of the first color light emitting part120, the first LEDs126can comprise at least one ultraviolet (UV) LED, and the phosphor129added to the first resin material128can comprise red phosphor, green phosphor, and blue phosphor.

Referring toFIGS. 1 and 3, the second color light emitting part130is formed in the second cavity131, and comprises second LEDs136and a second resin material138, and emits second color light.

The second LEDs136are green LEDs. The second LED136is attached on the third electrode143or the fourth electrode144located on the bottom of the second cavity131, and is electrically connected to the third electrode143and the fourth electrode144using wires137.

The second resin material138is formed in the second cavity131, protects the second LEDs136, and can be formed of transparent epoxy or silicon.

For another example of the second color light emitting part130, the second LEDs136are UV LEDs, and green phosphor can be added to the second resin material138. Light emitted from the UV LEDs are changed into green light by the green phosphor.

Meanwhile, each of the first and second LEDs126and136is mounted in a chip shape. In case of a horizontal device, a plurality of wires can be connected to two electrodes. In case of a vertical device, each chip can be attached on one of the electrodes using a conductive adhesive, and connected to the other using a wire. Also, the first and second LEDs126and136can be connected to two electrodes in a flip-chip method. The first and second LEDs126and136can change depending on a mounting method and the kind of the chip, and are not limited thereto.

Referring toFIGS. 2 and 3, the first and second color light emitting parts120and130can emit target color light through selective combination of LEDs of various colors, UV LEDs, and phosphor of various colors.

The surfaces of the first resin material128and the second resin material138can be at lease one of a concave shape, a convex shape, and a flat shape. A lens can be formed on the first resin material128and/or the second resin material138.

In the case where a plurality of first LEDs126are provided, they can be connection in series or in parallel. Also, in the case where a plurality of second LEDs136are provided, they can be connection in series or in parallel.

An electrostatic discharge (ESD) device can be mounted in the package body110. The ESD device is connected to the first LEDs126and the second LEDs136in parallel, and protects the first and second LEDs126and136from an overvoltage that may be applied thereto.

The first LEDs126of the first color light emitting part120, and the second LEDs136of the second color light emitting part130can be driven independently. For example, the first LEDs126and the second LEDs136can operate in inverted states, respectively, or can be turned-on/off simultaneously.

FIG. 4is a perspective view of a surface light source apparatus having the light emitting apparatus ofFIG. 1, andFIG. 5is a side cross-sectional view ofFIG. 4.

Referring toFIGS. 4 and 5, the surface light source apparatus150comprises a light emitting unit151and a surface light source unit153.

The light emitting unit151comprises a substrate101and at least one light emitting apparatus100. The substrate101can be realized in one of a metal substrate (for example, metal core PCB), a general PCB, and a flexible substrate. The substrate101can be another kind of substrate.

At least one light emitting apparatus100can be electrically connected on the substrate101. In the case where a plurality of light emitting apparatuses100are provided, they can be arranged on the substrate101in a predetermined direction with a predetermined interval.

A water-proof member such as silicon or epoxy can be formed between the substrate101and the light emitting apparatus100in order to protect an electrical characteristic.

The first color light emitting part120of the light emitting apparatus100is disposed on an upper portion of the substrate101, and the second color light emitting part130is disposed on a lower portion of the substrate101. Here, the disposed positions of the first color light emitting part120and the second color light emitting part130can change.

The surface light source unit153is disposed on one side of the light emitting unit151. The surface light source unit153is disposed in a light emission direction of the light emitting unit151to change incident point light into surface light and emit the same.

The surface light source unit153comprises a light guide plate (LGP)160and a reflector170. The LGP160guides light incident from the first color light emitting part120and/or the second color light emitting part130to illuminate the light in the form of surface light.

The LGP160can be formed of an acryl-based resin, for example, polymethyl methacrylate (PMMA). Reflective patterns (not shown) can be formed on an upper surface161of the LGP160. The reflective patterns are formed in a constant interval or a random interval to reflect incident light to a lower surface162.

Also, the reflector170is attached on the upper surface of the LGP160to reflect back light that leaks to the upper surface161of the LGP170. Also, the reflector170blocks light that leaks between the light emitting apparatus100and the LGP160. That is, the length of the reflector170can be longer than that of the LGP160.

A reflective material can be coated on surfaces160except the incident surface, the upper surface161, and the lower surface162of the LGP160to prevent light leakage.

Referring toFIG. 5, the substrate101comprises a driving control circuit105. The driving control circuit105selectively controls the first color light emitting part120and the second color light emitting part130to on/off modes.

When the first LEDs126of the first color light emitting part120are turned on, white light emitted from the first color light emitting part120is incident to the LGP160of the surface light source unit153. The light incident to the LGP160is guided into the LGP160, reflected by the reflector170and the reflective patterns (not shown), and illuminated in the form of surface light through the lower surface162of the LGP162. At this point, the second color light emitting part130can operate in the off mode.

When the second LEDs136of the second color light emitting part130are turned on, green light emitted from the second color light emitting part130is incident to the LGP160of the surface light source unit153. The light incident to the LGP160is guided into the LGP160, reflected by the reflector170and the reflective patterns (not shown), and illuminated in the form of surface light through the lower surface162of the LGP162.

The surface light source apparatus150can be applied to an apparatus requiring white light and green light, for example, to a cooling room and a freezing room of a refrigerator. In the case where the light emitting unit151is installed in a cooling room, the first color light emitting part120is turned on when a cooling room door is opened to illuminate white light to the inside of the cooling room, and is turned off when the cooling room door is closed. The second color light emitting part130is turned on when a refrigerator door is closed to illuminate green light to the inside of the cooling room, and is turned off when the refrigerator door is opened. The green light can maintain freshness of vegetables disposed inside the cooling room.

The light emitting unit151illuminates white light or green light as the refrigerator door is opened/closed to perform a lighting function and maintain freshness of vegetables disposed inside the cooling room. Embodiments can be applied to the field of a lighting as well as a general refrigerator and a kimchi refrigerator.

FIG. 6is a front view of a light emitting apparatus according to a second embodiment. In description of the second embodiment, explanations of the same parts as those of the first embodiment are omitted.

Referring toFIG. 6, a light emitting apparatus200comprises a package body210, a first color light emitting part220emitting blue light, and a second color light emitting part230emitting green light.

The first color light emitting part220is realized in a first cavity221of the package body210, and comprises first LEDs226and a first resin material228. The first LEDs226are blue LEDs, and the first resin material228is formed of transparent epoxy or silicon.

The second color light emitting part230is realized in a second cavity231of the package body210, and comprises second LEDs236and a second resin material238. The second LEDs236are green LEDs, and the second resin material238is formed of transparent epoxy or silicon. Here, in the second color light emitting part230, the second LED236can be UV LEDs and green phosphor can be added to the second resin material238to emit green light.

The first cavity221and the second cavity231of the package body210is divided by a divider216.

The first color light emitting part220emits blue light, and the second color light emitting part230emits green light. Unlike the first embodiment, the second embodiment does not use phosphor, and the blue light can be changed into white light by phosphor disposed on an external light path.

FIG. 7is a perspective view of a surface light source apparatus having the light emitting apparatus ofFIG. 6, andFIG. 8is a side cross-sectional view ofFIG. 7. In description of the surface light source apparatus, explanations of the same parts are omitted.

Referring toFIGS. 7 and 8, the surface light source apparatus250comprises a light emitting unit251and a surface light source unit253.

The light emitting unit251comprises a light emitting apparatus200and a substrate201. At least one light emitting apparatus200can be disposed on the substrate201. In the case where a plurality of light emitting apparatuses200are disposed, they can be disposed in a predetermined direction.

A first color light emitting part220is disposed on the upper portion of the light emitting unit251, and a second color light emitting part230is disposed on the lower portion of the light emitting unit251. The first color light emitting part220emits blue light, and the second color light emitting part230emits green light.

A driving control circuit205can be disposed on a predetermined portion of the substrate201to control the first color light emitting part220and the second color light emitting part230.

The surface light source unit253comprises a first LGP260A, a second LGP260B, a reflector270, and a color filter film275.

The first LGP260A corresponds to the first color light emitting part220, and the second LGP260B corresponds to the second color light emitting part230.

The first LGP260A changes incident blue light into white light. For this purpose, yellow phosphor can be added to the first LGP260A when the first LGP260A is manufactured. Alternatively, at least one of the incident surface, the upper surface, and the lower surface, which is a light emission surface of the first LGP260A, can be coated with yellow phosphor.

The reflector270is disposed on the first LGP260A, and the color filter film275is dispose between the first LGP260A and the second LGP260B.

A reflective material can be coated on surfaces except the incident surface, the upper surface, and the lower surface of the first LGP260A and the second LGP260B to block light leaking to the outside.

The color filter film275is disposed between the first LGP260A and the second LGP260B. The color filter film275transmits all of light incident from the first LGP260A, and reflects green light incident from the second LGP260B.

Blue light emitted from the first color light emitting part220is incident to the first LGP260A, and a portion of the blue light is guided to the inside of the first LGP260A and changed into yellow light by phosphor coated inside the first LGP260A. At this point, yellow light, blue light, and white light obtained by mixing the yellow light and the blue light can be emitted to the lower surface, which is a light emission surface of the first LGP260A.

Also, light incident to the first LGP260A is emitted to the lower direction in the form of surface light by reflective patterns (not shown) of the first LGP260A and the reflector270. At this point, the light emitted from the first LGP260A passes through the color filter film275and is illuminated as white light by way of the second LGP260B.

Green light emitted from the second color light emitting part230is incident to the second LGP260B. The green light incident to the second LGP260B is guided to the inside of the second LGP260B, and reflected by reflective patterns of the second LGP260B and the color filter film275, and illuminated to the lower surface of the second LGP260B in the form of surface light.

Referring toFIG. 8, a driving control circuit205can be disposed on a predetermined portion of the substrate201.

The light emitting unit251emits at least one of blue light and green light. The blue light is emitted as white surface light L1by the first LGP260A, and the green light is emitted as green surface light L2by the second LGP260B. The color filter film275transmits light incident from the first LGP260A, and reflects light incident to the second LGP260B. This structure selectively transmits or reflects light using the color filter film275located between the first LGP260aand the second LGP260B, so that the light can be illuminated as white light or green light.

The disposed positions of the first color light emitting part220, the first LGP260A, the second color light emitting part230, and the second LGP260B can change.

FIG. 9is a front view of a light emitting apparatus according to a third embodiment, andFIG. 10is a cross-sectional view ofFIG. 9, taken along a line C-C.

Referring toFIGS. 9 and 10, the light emitting apparatus300comprises a package body310, a first cavity321, a second cavity331, a plurality of lead frames341,342,343, and344, a first color light emitting part320, and a second color light emitting part330.

The package body310can be formed of one of poly phthal amid (PPA), liquid crystal polymer (LCP), and syndiotactic polystyrene (SPS).

A first lead frame341and a second lead frame342are formed in the first cavity321of the package body310. The first lead frame341and the second lead frame342pass through the package body310at the bottom of the first cavity321and is exposed to the outside, and used as electrode terminals. Also, a third lead frame343and a fourth lead frame344are formed in the second cavity331of the package body310. The third lead frame343and the fourth lead frame344pass through the package body310at the bottom of the second cavity331and is exposed to the outside, and used as electrode terminals.

The first color light emitting part320is formed in the first cavity321, and comprises first LEDs326and a first resin material338. The first LED326is attached on one of the first lead frame341or the second lead frame342, and electrically connected to the first and second lead frames341and342using wires327.

The second color light emitting part330is formed in the second cavity331, and comprises second LEDs336and a second resin material338. The second LED336is attached on one of the third lead frame343or the fourth lead frame344, and electrically connected to the third and fourth lead frames343and344using wires337.

The first and second LEDs326and336can be connected to the plurality of lead frames using a flip-chip method or at least one wire, and there is no limitation in connection the first and second LEDs326and336.

Also, the first LEDs326of the first color light emitting part320can be formed in one group of a blue LED group, a UV LED group, a red/green/blue LED group. The first color light emitting part320can emit white light. The white light can be realized using a blue LED and a yellow LED, or using the UV LED and red/green/yellow phosphor, or the red/green/blue LEDs.

The second LEDs336of the second color light emitting part330comprise a green LED or a UV LED. The second color light emitting part330emits green light. The green light can be realized using a green LED, or using a UV LED and green phosphor.

A surface light apparatus can be realized by disposing the surface light source unit of the first embodiment or the surface light source unit of the second embodiment in the light emission direction of the light emitting apparatus300. Accordingly, at least one of white light and green light can be provided in the form of surface light.

According to the embodiments, since one package emits white light and green light, the package can be installed in a place requiring white light and green light, for example, the inside of a refrigerator. Therefore, the white light is illuminated when a door of the refrigerator is opened, and green light is illuminated when the door of the refrigerator is closed to maintain freshness of vegetables in a cooling room.

Also, the white light and the green light can be provided in the form of surface light.