Lighting device

A light emitting device package may be provided that includes: a package body which includes a first cavity and a second cavity which are formed to be depressed in at least a portion of the package body; a first light emitting device and a second light emitting device, each of which is disposed in the first cavity and the second cavity respectively; and a first fluorescent substance and a second fluorescent substance, each of which is filled in the first cavity and the second cavity respectively.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority under 35 U.S.C. §119(e) of Korean Patent Application No. 10-2011-0086885 filed Aug. 30, 2011 the subject matters of which are incorporated herein by reference.

BACKGROUND

This embodiment relates to a light emitting device package capable of controlling a color temperature.

In general, an electric bulb or a fluorescent lamp is commonly used as an indoor or outdoor lighting lamp. However, the electric bulb or the fluorescent lamp has a short life span, so that it should be frequently changed. Moreover, a conventional fluorescent lamp is degraded due to elapse of time for its use. As a result, it is often that its illuminance is gradually decreased.

In order to overcome such problems, a lighting apparatus is now being developed by using a light emitting device (hereinafter, referred to as LED). The LED is easy to control and has a rapid response speed, high electro-optic conversion efficiency, a long life span, low power consumption and high luminance. The LED is also used to create emotional lighting.

Recently, there is a requirement for emotional lighting. Therefore, technologies for effectively controlling a color temperature of the light emitting device are being developed.

However, according to a general method for controlling a color temperature, at least two light emitting device package are required.

SUMMARY

One embodiment is a lighting module. The lighting module includes: a package body which includes a first cavity which is formed to be depressed in at least a portion of the package body and a second cavity which is formed to be depressed in at least a portion of the bottom surface of the first cavity; a first light emitting device and a second light emitting device, each of which is disposed in the first cavity and the second cavity respectively; and a first fluorescent substance and a second fluorescent substance, each of which is filled in the first cavity and the second cavity respectively.

Another embodiment is a lighting module. The lighting module includes: a first fluorescent substance which receives an output of a first light emitting device and emits light;

a second fluorescent substance which receives an output of a second light emitting device and emits light; and a package body which receives the first fluorescent substance and the second first fluorescent substance such that the first fluorescent substance is disposed on the second fluorescent substance.

DETAILED DESCRIPTION

A thickness or a size of each layer may be magnified, omitted or schematically shown for the purpose of convenience and clearness of description. The size of each component may not necessarily mean its actual size.

It should be understood that when an element is referred to as being ‘on’ or “under” another element, it may be directly on/under the element, and/or one or more intervening elements may also be present. When an element is referred to as being ‘on’ or ‘under’, ‘under the element’ as well as ‘on the element’ may be included based on the element.

An embodiment may be described in detail with reference to the accompanying drawings.

FIG. 1is a view for describing a method for controlling a color temperature for a light emitting device.

Referring toFIG. 1, a plurality of light emitting device packages10and20may be used to control a color temperature.

For example, when it is assumed that a first light emitting device package10represents a color temperature of 5,000 K and a second light emitting device package20represents a color temperature of 3,000 K, if only the first light emitting device package10becomes in an ON-state, light having a color temperature of 5,000 K is emitted, and if only the second light emitting device package20becomes in an ON-state, light having a color temperature of 3,000 K is emitted. Also, if both of the first and the second light emitting device packages10and20become in an ON-state, it is possible to emit light having a color temperature between 3,000 K and 5,000 K by controlling the luminance ratio thereof.

FIG. 2is a view showing the range of light which is emitted by the above-described method.

FIG. 3is a plan view showing a configuration of an embodiment-based light emitting device package capable of controlling the color temperature.FIG. 4is a cross sectional view of the light emitting device package ofFIG. 3taken along line A-A′.FIG. 5is a cross sectional view of the light emitting device package ofFIG. 3taken along line B-B′.

Referring toFIGS. 3 to 5, the light emitting device package according to the embodiment includes a first cavity110, a second cavity120, light emitting devices111and121, each of which is disposed in the cavities110and120respectively.

The first and the second cavities110and120are formed by depressing at least a portion of a package body100. The first cavity110may be formed in at least a portion of the package body100, and the second cavity120may be formed in another portion of the package body100independently of the first cavity110. It is recommended that the first cavity110is formed by depressing the top surface of the package body100, and then the second cavity120is formed by depressing at least a portion of the bottom surface of the first cavity110. Referring toFIGS. 3 to 5, the first cavity110is formed by forming a first depression having a first radius based on a particular point of the package body100(for example, a central point). The second cavity120is formed by forming a second depression having a second radius less than the first radius on the basis of a particular point of the first depression (for example, a central point). However, there is no limit to this. In other words, the cavities110and120are not necessarily formed in the form of a circle as viewed from the top of the package body100, and it is enough as long as the second cavity120is formed at at least one point within the first cavity110.

The at least one light emitting device111is disposed on the bottom surface of the first cavity110. The at least one light emitting device121is disposed on the bottom surface of the second cavity120. Though the drawings show that the one light emitting device111is disposed at the center of the bottom surface of the first cavity110and the two light emitting devices121are disposed symmetrically on the bottom surface of the second cavity120on the basis of the center of the bottom surface of the first cavity110, there is no limit to this. That is, the number of the light emitting devices111and121which are disposed in the first and the second cavities110and120may be different from that of the above-mentioned case shown in the drawings. Also, it can be considered that a plurality of the light emitting devices111and121are not necessarily symmetrically disposed. It is possible that a height from the bottom surface of the first cavity110to the surface of the package body100(depth of the first cavity110) is different from a height from the bottom surface of the first cavity110to the bottom surface of the second cavity120(depth of the second cavity120).

While the light emitting devices111and121can be preferably implemented by a light emitting diode (LED), any device capable of emitting light can be used as the light emitting devices111and121according to the embodiment. At least one of the light emitting device111disposed in the first cavity110and the light emitting device121disposed in the second cavity120may be a light emitting device emitting blue light. However, there is no limit to this.

Fluorescent substances112and122are filled in the first cavity110and the second cavity120respectively. Specifically, the fluorescent substance122is filled in the second cavity120up to the height from the bottom surface of the second cavity120to the bottom surface of the first cavity110. The fluorescent substance112is filled in the first cavity110from the bottom surface thereof to the top surface of the package body100in such a manner as to cover the entire second cavity120. Any one of the fluorescent substance112filled in the first cavity110and the fluorescent substance122filled in the second cavity120may be a red fluorescent substance, and the other one may be either a yellow fluorescent substance or a green fluorescent substance. However, there is no limit to this. As the mutually different fluorescent substances or the fluorescent substances emitting mutually different color light are filled in the first and the second cavities110and120, the color temperature or color of the light emitted from the entire light emitting device package can be changed. For example, a light output of any one of the light emitting device111of the first cavity110and the light emitting device121of the second cavity120is adjusted, so that the color temperature can be controlled.

Insulators131,132and133are further formed in the package body100in order to insulate each of the light emitting devices111and121. The insulators131,132and133may be formed to insulate the anode from the cathode of one of the light emitting devices111and121, or may be formed to insulate the light emitting devices111and121. For example, the first insulator131shown inFIGS. 3 and 4is formed to insulate an anode connection line from a cathode connection line of the light emitting device121disposed in the second cavity120. Meanwhile, the second insulator132and the third insulator133shown inFIGS. 3 and 5may be foamed to insulate the light emitting device111disposed in the first cavity110from another light emitting device111. Since each of the insulators131,132and133is formed to vertically penetrate the package body100, complete electrical insulation can be obtained.

According to the embodiment, a plurality of the cavities110and120are formed, the light emitting devices111and121, each of which is disposed in the cavities110and120respectively, and the cavities110and120are filled with mutually different fluorescent substances. As a result, the outputs of the light emitting devices111and121, each of which is disposed in the cavities110and120respectively, are controlled even only by one package, so that it is possible to control the color or color temperature of the light emitted from the light emitting device package.