KR20160009832A - Lighting device - Google Patents

Abstract

An embodiment relates to a light emitting device. The light emitting device according to the present invention includes a substrate; a light emitting element arranged on the substrate; a first wavelength conversion layer which is arranged on the light emitting element and converts part of a beam emitted from the light emitting element into a beam having a wavelength different from the wavelength of the beam emitted from the light emitting element; and a second wavelength conversion layer which is arranged on the first wavelength conversion layer and converts part of a beam emitted from the first wavelength conversion layer into a beam having a wavelength different from the wavelength of the beam emitted from the first wavelength conversion layer. The first wavelength conversion layer and the second wavelength conversion layer include light transmission materials. At least one of the light transmission material of the first wavelength conversion layer and the light transmission material of the second wavelength conversion layer is ceramic.

Description

[0001] LIGHTING DEVICE [0002]

An embodiment relates to a light emitting device.

Light emitting diodes (LEDs) are a type of semiconductor devices that convert electrical energy into light. The light emitting diode has advantages of low power consumption, semi-permanent lifetime, fast response speed, safety, and environmental friendliness compared with conventional light sources such as fluorescent lamps and incandescent lamps. Therefore, much research has been conducted to replace conventional light sources with light emitting diodes. Light emitting diodes are increasingly used as light sources for various lamps used in indoor / outdoor, liquid crystal display devices, electric sign boards, streetlights, and the like .

Conventionally, there is a light emitting device using a single wavelength conversion layer on the light emitting surface of a light emitting diode among light emitting devices using light emitting diodes.

In such a conventional light emitting device, there is a problem that it is somewhat difficult and cumbersome to implement a desired color temperature by a designer using one wavelength conversion layer.

Embodiments provide a light emitting device that can easily implement color temperature and can extend the range of color temperature.

In addition, the embodiment provides a light emitting device capable of removing stains on the light emitting surface.

Further, the embodiment provides a light emitting device capable of improving light extraction efficiency.

Further, the embodiment provides a light emitting device capable of improving the color rendering property of emitted light.

A light emitting device according to an embodiment includes: a substrate; A light emitting element disposed on the substrate; A first wavelength conversion layer disposed on the light emitting element and converting part of the light emitted from the light emitting element into light having a wavelength different from a wavelength of the light emitted from the light emitting element; And a second wavelength conversion layer disposed on the first wavelength conversion layer and converting part of the light emitted from the first wavelength conversion layer into light having a wavelength different from a wavelength of the light emitted from the first wavelength conversion layer, Wherein the first wavelength conversion layer and the second wavelength conversion layer comprise a transmissive material, and at least one of the transmissive material of the first wavelength conversion layer and the transmissive material of the second wavelength conversion layer is a ceramic to be.

A light emitting device according to an embodiment includes: a substrate; A light emitting element disposed on the substrate; A first wavelength conversion layer disposed on the light emitting element, the first wavelength conversion layer including a first fluorescent material; And a second wavelength conversion layer disposed on the first wavelength conversion layer and including a second fluorescent material, wherein the first wavelength conversion layer includes a plurality of wavelength conversion layers, and the plurality of wavelengths Each of the conversion layers includes either glass or ceramic, and the second wavelength conversion layer includes glass.

When the light emitting device according to the embodiment is used, the color temperature can be easily implemented and the range of the color temperature can be expanded.

In addition, there is an advantage that stains on the light emitting surface can be removed.

Further, there is an advantage that the light extraction efficiency can be improved.

Further, there is an advantage that the color rendering property of emitted light can be improved.

1 is a perspective view of a light emitting device according to a first embodiment;
2 is a cross-sectional view of the light emitting device shown in Fig.
3 is a cross-sectional view of a modification of the light emitting device shown in Fig. 2
4 is a color coordinate diagram for explaining the effect of the light emitting device according to the first embodiment shown in Fig.
5 to 6 are diagrams for explaining the effect when at least one or both of the transmissive materials of the first wavelength conversion layer 150 and the second wavelength conversion layer 160 are ceramics.
7 is a perspective view of a light emitting device according to a second embodiment;
8 is a cross-sectional view of the light emitting device shown in Fig.
Fig. 9 is a color coordinate diagram for explaining the effect of the light emitting device according to the second embodiment shown in Fig. 7; Fig.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size of each component does not entirely reflect the actual size.

In the description of the embodiments according to the present invention, in the case where an element is described as being formed "on or under" another element, the upper (upper) or lower (lower) (On or under) all include that the two elements are in direct contact with each other or that one or more other elements are indirectly formed between the two elements. Also, when expressed as "on or under", it may include not only an upward direction but also a downward direction with respect to one element.

Hereinafter, a light emitting device according to an embodiment of the present invention will be described with reference to the accompanying drawings.

≪ First Embodiment >

FIG. 1 is a perspective view of a light emitting device according to a first embodiment, and FIG. 2 is a cross-sectional view of the light emitting device shown in FIG.

1 and 2, a light emitting device according to the first embodiment includes a substrate 110, a first electrode layer 120, a second electrode layer 130, a light emitting element 140, a first wavelength conversion layer 150 and a second wavelength conversion layer 160. [

The first electrode layer 120 and the second electrode layer 130, the light emitting device 140, the first wavelength conversion layer 150, and the second wavelength conversion layer 160 may be disposed on the substrate 110.

The substrate 110 serves as a body and may be various types such as a printed circuit board (PCB), a silicon wafer, a resin, and a sub-mount. In addition, the substrate 110 may be classified into a plastic package, a ceramic package, a metal package, or the like depending on the material used.

An insulating layer (not shown) may be disposed on the substrate 110. The insulating layer (not shown) serves to cut off the electrical connection between the substrate 110 and other components. However, if the substrate 110 is made of a nonconductive material, an insulating layer (not shown) may not be disposed.

The first electrode layer 120 and the second electrode layer 130 are disposed on the upper surface of the substrate 110. The first electrode layer 120 and the second electrode layer 130 are spaced apart from each other on the upper surface of the substrate 110. Accordingly, the first electrode layer 120 and the second electrode layer 130 are electrically separated from each other.

The first electrode layer 120 and the second electrode layer 130 are electrically conductive materials and are electrically connected to the light emitting device 140.

The light emitting device 140 is disposed on the first electrode layer 120. The first electrode layer 120 is electrically connected to one of the two electrodes of the light emitting device 140.

The light emitting device 140 may be disposed on the substrate 110 and disposed on the upper surface of the first electrode layer 120.

The light emitting device 140 may include a light emitting structure including a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer. For example, the light emitting structure may include an active layer disposed between the first conductive semiconductor layer and the second conductive semiconductor layer.

The first conductive semiconductor layer may include an n-type semiconductor layer and may be selected from among GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, An n-type dopant such as Se or Te can be doped.

In the active layer, electrons (or holes) injected through the first conductive type semiconductor layer and holes (or electrons) injected through the second conductive type semiconductor layer meet with each other to form an energy band corresponding to the formation material of the active layer, Is a layer which emits light due to a difference in band gap of the light emitting layer. The active layer may be formed of any one of a single well structure, a multi-well structure, a quantum dot structure, or a quantum wire structure, but is not limited thereto.

The second conductivity type semiconductor layer may be a p-type semiconductor layer and may be selected from GaN, AlN, AlGaN, InGaN, InN, InAlGaN, AlInN, AlGaAs, GaP, GaAs, GaAsP, AlGaInP, A p-type dopant such as Sr, Ba or the like may be doped.

Meanwhile, the first conductivity type semiconductor layer may include a p-type semiconductor layer and the second conductivity type semiconductor layer may include an n-type semiconductor layer. Further, a semiconductor layer including an n-type or p-type semiconductor layer may be further formed under the second conductive type semiconductor layer. Accordingly, the light emitting structure may include at least one of an n-p junction structure, a p-n junction structure, an n-p-n junction structure, and a p-n-p junction structure.

The light emitting device 140 can selectively emit light in the range of the visible light band to the ultraviolet light band, and emit light having a color inherent to the semiconductor material.

The light emitting devices 140 may be disposed on the upper surface of the first electrode layer 120 in a single or a plurality of layers. The light emitting device 140 may be a light emitting diode chip that emits visible light such as red, green, or blue light, or a light emitting diode chip that emits ultraviolet light.

The light emitting device 140 may have a first electrode (not shown) and a second electrode 147. The first electrode (not shown) of the light emitting device 140 is formed on the lower surface of the light emitting device 140 and electrically connected to the first electrode layer 120 directly. The second electrode 147 is electrically connected to the second electrode layer 130, And may be electrically connected through wires W.

Here, as shown in the figure, the second electrode 147 of the light emitting device 140 may be plural. For example, the number of the second electrodes 147 may be two. The two second electrodes 147 may be connected to the second electrode layer 130 through two wires, respectively. When the second electrode 147 of the light emitting element 140 is connected to the second electrode layer 130 through a plurality of wires, the luminance distribution of the light emitting surface is higher than the light emitting element or the flip- And there is also an advantage that the color deviation is reduced. Thereby, there is an advantage that the reliability of the light emitting element is improved and the unevenness due to the light emission can be reduced.

The first wavelength conversion layer 150 is disposed on the light emitting device 140. The light emitting device 140 may include an upper surface 141 on which the first wavelength conversion layer 150 is disposed.

The upper surface 141 of the light emitting device 140 may include a portion where the second electrode 147 connected to the wire W is disposed and includes a light emitting surface 145 through which light is actually emitted. Here, the area of the light emitting surface 145 is smaller than the area of the top surface 141.

The first wavelength conversion layer 150 is disposed on the light emitting element 140.

The first wavelength conversion layer 150 may be disposed on the upper surface 141 of the light emitting device 140. Here, the first wavelength conversion layer 150 may not be disposed on the second electrode 147 of the light emitting device 140. This is for connecting the second electrode 147 to the wire W. [ Therefore, the first wavelength conversion layer 150 may have a predetermined groove 157 at one corner.

The area of the lower surface 153 of the first wavelength conversion layer 150 may be smaller than the area of the upper surface 141 of the light emitting device 140. This is because the second electrode 147 of the light emitting element 140 can be disposed on the upper surface 141 of the light emitting element 140.

The area of the lower surface 153 of the first wavelength conversion layer 150 may be larger than the area of the light emitting surface 145 of the light emitting element 140. This is because all the light emitted from the light emitting surface 145 passes through the first wavelength conversion layer 150.

The lower surface 153 of the first wavelength conversion layer 150 may cover the entire light emitting surface 145 of the light emitting device 140. This is because all the light emitted from the light emitting surface 145 passes through the first wavelength conversion layer 150.

The thickness of the first wavelength conversion layer 150 may be 50um or more and 200um or less. The thickness of the first wavelength conversion layer 150 depends on the target color temperature of the light emitting device according to the embodiment.

The first wavelength conversion layer 150 may convert a part of the light emitted from the light emitting device 140 into light having a different wavelength from that of the light emitted from the light emitting device 140. Specifically, the first wavelength conversion layer 150 converts part of the main light emitted from the light emitting device 140 into first light having a different wavelength from the wavelength of the main light, It is possible to emit the non-converted primary light and the first light which are not converted to light.

The first wavelength conversion layer 150 may include a fluorescent material capable of converting the primary light emitted from the light emitting device 140 into the first light. The fluorescent material is described later together with the fluorescent material of the second wavelength conversion layer 160.

The first wavelength conversion layer 150 may include the fluorescent material and the light transmitting material. Here, the light transmitting material may be glass or ceramic.

The second wavelength conversion layer 160 is disposed on the first wavelength conversion layer 150. The lower surface 163 of the second wavelength conversion layer 160 is disposed on the upper surface 151 of the first wavelength conversion layer 150.

The width of the second wavelength conversion layer 160 may be smaller than the width of the first wavelength conversion layer 150. The area of the lower surface 163 of the second wavelength conversion layer 160 may be smaller than the area of the upper surface 151 of the first wavelength conversion layer 150. However, the width of the second wavelength conversion layer 160 may be larger than the width of the first wavelength conversion layer 150. Will be described with reference to FIG.

3 is a cross-sectional view of a modification of the light emitting device shown in Fig.

3, the lower surface 163 'of the second wavelength conversion layer 160' is disposed on the upper surface 151 of the first wavelength conversion layer 150, and the width of the second wavelength conversion layer 160 ' Is larger than the width of the first wavelength conversion layer 150, all light emitted from the first wavelength conversion layer 150 is incident on the second wavelength conversion layer 160 '. Therefore, when the light emitting device is viewed from the outside There is an advantage that no unevenness is generated in the light emitting surface 161 'of the light emitting device.

The area of the lower surface 163 'of the second wavelength conversion layer 160' is larger than the area of the upper surface 151 of the first wavelength conversion layer 150. The lower surface 163 'of the second wavelength conversion layer 160' is disposed on the upper surface 151 of the first wavelength conversion layer 150 and the area of the lower surface 163 'of the second wavelength conversion layer 160' Is larger than the area of the upper surface 151 of the first wavelength conversion layer 150, all the light emitted from the first wavelength conversion layer 150 is incident on the second wavelength conversion layer 160 ' There is an advantage that no unevenness is generated on the light emitting surface of the light emitting device when the device is viewed from the outside.

Referring again to FIGS. 1 and 2, the thickness of the second wavelength conversion layer 160 may be 50um or more and 200um or less. The thickness of the second wavelength conversion layer 160 depends on the color temperature of the target of the light emitting device according to the embodiment.

The second wavelength conversion layer 160 may convert part of the light emitted from the first wavelength conversion layer 150 into light having a different wavelength from that of the light emitted from the first wavelength conversion layer 150. Specifically, the second wavelength conversion layer 160 reflects a part of the non-converted main light emitted from the light emitting device 140 and not converted into the first light in the first wavelength conversion layer 150 by the wavelength of the main light and the wavelength of the first light The second light having different wavelengths from the non-converted main light, and the remaining unconverted main light can be emitted as it is. Also, the second wavelength conversion layer 160 emits the first light emitted from the first wavelength conversion layer 150 as it is. Accordingly, in the second wavelength conversion layer 160, the main light of the light emitting device 140 including the second light and the first light of the first wavelength conversion layer 150 can be mixed and emitted.

The second wavelength conversion layer 160 may include a fluorescent material capable of converting the main light emitted from the light emitting device 140 into the second light. The fluorescent material will be described later together with the fluorescent material of the first wavelength conversion layer 150.

The second wavelength conversion layer 160 may include the fluorescent material and the light transmitting material. Here, the light transmitting material may be glass or ceramic.

The first wavelength conversion layer 150 and the second wavelength conversion layer 160 will be described in detail below.

Since the light emitting device according to the first embodiment includes the first wavelength conversion layer 150 and the second wavelength conversion layer 160, it is easy to adjust the color temperature to easily realize a desired color temperature of the designer, Can be expanded. This will be described in detail with reference to FIG.

4 is a color coordinate diagram for explaining the effect of the light emitting device according to the first embodiment shown in Fig.

4, a straight line A is a straight line of a color coordinate system by the first wavelength conversion layer 150, and a straight line B is a straight line of a color coordinate system by the second wavelength conversion layer 160.

Referring to FIG. 4, since there is only one wavelength conversion layer, the color temperature changes only on the straight line of the corresponding color coordinate. Therefore, the color temperature control of the light emitting device having only one wavelength conversion layer is very limited. However, as in the light emitting device according to the first embodiment, when the wavelength conversion layer is two or more, it is easy for the designer to adjust the desired color temperature in the range between the straight line A and the straight line B, The desired color temperature can be determined and the color temperature range is advantageously enlarged.

1 and 2, each of the first wavelength conversion layer 150 and the second wavelength conversion layer 160 may include a fluorescent material and a light transmitting material.

The light transmitting material of each of the first wavelength conversion layer 150 and the second wavelength conversion layer 160 may be any one of glass and ceramics. If the light-transmitting material is glass, there is an advantage that two or more different phosphors can be mixed.

Here, at least one of the light transmitting materials of the first wavelength conversion layer 150 and the second wavelength conversion layer 160 may be a ceramic. If at least one of the light transmitting materials of the first wavelength conversion layer 150 and the second wavelength conversion layer 160 is a ceramic, a uniform color temperature distribution can be obtained on the light emitting surface of the light emitting device. Will be described with reference to Figs. 5 to 6. Fig.

5 to 6 are diagrams for explaining the effect when at least one or both of the transmissive materials of the first wavelength conversion layer 150 and the second wavelength conversion layer 160 are ceramics.

5 illustrates a case where only the first wavelength conversion layer 150 including glass and a phosphor is formed on the light emitting device 140 shown in FIG. 1 (the second wavelength conversion layer 160 is removed) And a light emitting surface on which light is emitted from the conversion layer 150. Referring to FIG. 5, it can be seen that the color temperature distribution on the upper surface of the first wavelength conversion layer 150, that is, the light emitting surface is somewhat uniform.

6 (a) is a diagram illustrating a method of selecting a plurality of points arbitrarily from the light emitting surface of the first wavelength conversion layer 150 of FIG. 5, calculating the color temperature x coordinate and the color temperature y coordinate at each point, (x-axis) and the number of stars (y-axis). Here,? X is obtained by subtracting the x-coordinate calculated from the target x-coordinate, and? Y is obtained by subtracting the y-coordinate calculated from the target y-coordinate.

6 (b) is a graph when the glass of the first wavelength conversion layer 150 of FIG. 5 is replaced with a ceramic.

6 (a) and 6 (b), it can be confirmed that the color temperature distribution is uneven because the color temperature distribution is somewhat wider in the glass, and since the ceramic color temperature distribution is narrow, Uniformity can be confirmed.

5 to 6, when any one of the first wavelength converter 150 and the second wavelength converter 160 is a ceramic material, the second wavelength converter 150 and the second wavelength converter 160 may be disposed on the light emitting surface of the second wavelength converter 160 It can be expected that the color temperature distribution becomes uniform.

Accordingly, the light transmitting material of the first wavelength conversion layer 150 may be glass, and the light transmitting material of the second wavelength conversion layer 160 may be ceramic. In addition, the light transmitting material of the first wavelength conversion layer 150 may be ceramic, and the light transmitting material of the second wavelength conversion layer 160 may be glass.

Here, the translucent material of the second wavelength conversion layer 160 is glass rather than ceramics, which is more effective in light extraction efficiency of the light emitting device. Specifically, when the light transmitting material of the first wavelength conversion layer 150 is ceramic and the light transmitting material of the second wavelength conversion layer 160 is glass, the light extraction efficiency of the light emitting device can be further improved have. The reason for this is as follows. When the light transmitting material of the first wavelength conversion layer 150 is glass and the light transmitting material of the second wavelength conversion layer 160 is ceramic, the upper surface 161 of the second wavelength conversion layer 160 is made of air . When the second wavelength conversion layer 160 is made of ceramics such as sapphire (Al 2 O 3), the refractive index of sapphire is higher than that of air or glass The amount of light that can not transmit the upper surface 161 of the second wavelength conversion layer 160 among the light incident on the second wavelength conversion layer 160 in the first wavelength conversion layer 150 is larger than the amount of light that is transmitted through the second wavelength conversion layer 160. [ May be greater than when glass 160 is glass. Therefore, if one of the first wavelength conversion layer 150 and the second wavelength conversion layer 160 is a ceramic and the other is a glass, the second conversion layer 160, which is in direct contact with air, .

The fluorescent material of the first wavelength conversion layer 150 and the second wavelength conversion layer 160 may be a phosphor.

The phosphor may include at least one of a garnet system (YAG, TAG), a silicate system, a nitride system, and an oxynitride system.

The phosphor may include a yellow phosphor, a green phosphor, and a red phosphor.

The yellow phosphor is excited by light of 500 nm or less and emits light having a peak wavelength between 530 nm and 580 nm. The yellow phosphor may be a silicate-based, garnet-based YAG or oxynitride-based phosphor. The yellow phosphor may be selected from among phosphors selected from Y3Al5O12: Ce3 + (Ce: YAG), CaAlSiN3: Ce3 +, Eu2 + -SiAlON series, and / or BOSE series. The yellow phosphor may also be doped to any suitable level to provide light output of the desired wavelength. Ce and / or Eu may be doped into the phosphor at a dopant concentration ranging from about 0.1% to about 20%.

The green phosphor is excited by light of 400 nm or less and emits light having a dominant wavelength between 450 nm and 530 nm. The green phosphor may be a silicate-based, nitride-based or oxynitride-based phosphor.

The red phosphor is excited by light of 580 nm or less and emits light having a dominant wavelength between 600 nm and 650 nm. The red phosphor may be a nitride-based or sulfide-based phosphor. The red phosphors may include CaAlSiN3: Eu2 + and Sr2Si5N8: Eu2 +. This phosphor can maintain the quantum efficiency at 80% or higher at a temperature of 150 캜 or higher. Other red phosphors that may be used include phosphors selected from CaSiN2: Ce3 +, CaSiN2: Eu2 + as well as Eu2 + -SiAlON phosphor series, and / or phosphors selected from the (Ca, Si, Ba) SiO4: Eu2 + (BOSE) series.

The first wavelength conversion layer 150 may include a yellow phosphor and the second wavelength conversion layer 160 may include a red phosphor. However, the present invention is not limited thereto, and the first wavelength conversion layer 150 may include a red phosphor and the second wavelength conversion layer 160 may include a yellow phosphor. When the first wavelength conversion layer 150 includes a red phosphor and the second wavelength conversion layer 160 includes a yellow phosphor, light extraction efficiency may be improved as compared with the opposite case. If the first wavelength conversion layer 150 includes a yellow phosphor and the second wavelength conversion layer 160 includes a red phosphor, the light emitted from the yellow phosphor of the first wavelength conversion layer 150 580 nm) excites the red phosphor of the second wavelength conversion layer 160 and can not be transmitted through the second wavelength conversion layer 160 and can be absorbed by the red phosphor.

Referring again to FIGS. 1 and 2, the thickness of the first wavelength converter 150 may be equal to or different from the thickness of the second wavelength converter 160. When the thickness of the first wavelength converter 150 and the thickness of the second wavelength converter 160 are different from each other, different effects can be obtained. Specifically, if the thickness of the second wavelength converter 160 is larger than the thickness of the first wavelength converter 150, the light emitting device according to the first embodiment can be used for a fluorescent lamp that emits white light . Conversely, if the thickness of the first wavelength converter 150 is larger than the thickness of the second wavelength converter 160, the light emitting device according to the first embodiment can be used for an incandescent lamp that emits orange light.

The light emitting device 140 and the first wavelength conversion layer 150 and the first and second wavelength conversion layers 150 and 160 may be bonded to each other through an adhesive (not shown). It is possible to prevent light from leaking into a gap between the first wavelength conversion layer 150 and the light emitting device 140 and between the second wavelength conversion layer 160 and the first wavelength conversion layer 150 have. The first wavelength conversion layer 150 is bonded to the light emitting device 140 and the second wavelength conversion layer 160 is bonded to the first wavelength conversion layer 150 to form the first and second wavelength conversion layers 150, and 160 can stably light the light from the light emitting device 140. [

The adhesive material (not shown) may be made of heat-resistant or light-resistant material. For example, it may be silicon, fluorine resin, or inorganic (glass) paste. When the adhesive material (not shown) has high heat resistance and high light resistance, the reliability of the light emitting device is improved, and the light flux maintaining rate can be improved.

The wire W can be selected in consideration of the reliability, productivity, cost, and performance of the product. As the material of the wire W, metals such as gold (Au), silver (Ag), copper (Cu), and aluminum (Al)

≪ Second Embodiment >

Fig. 7 is a perspective view of the light emitting device according to the second embodiment, and Fig. 8 is a sectional view of the light emitting device shown in Fig.

7 to 8, the light emitting device according to the second embodiment includes a substrate 110, a first electrode layer 120, a second electrode layer 130, a light emitting element 140, a second wavelength conversion layer 250, a second wavelength conversion layer 260, and a third wavelength conversion layer 270.

Since the substrate 110, the first electrode layer 120, the second electrode layer 130, and the light emitting device 140 are the same as those of the light emitting device according to the first embodiment shown in FIGS. 1 and 2, And the first to third wavelength conversion layers 250, 260, and 270 will be described in detail below.

The first wavelength conversion layer 250 is disposed on the light emitting device 140 and the second wavelength conversion layer 260 is disposed on the first wavelength conversion layer 250. The third wavelength conversion layer 270 is disposed on the first wavelength conversion layer 250, And is disposed on the second wavelength conversion layer 260.

The first wavelength conversion layer 250 is the same as the first wavelength conversion layer 150 of the light emitting device shown in FIGS. 1 and 2, and the third wavelength conversion layer 270 is the same as the first May be the same as the second wavelength conversion layer 160 of the device. Therefore, the light emitting device according to the second embodiment may further include the second wavelength conversion layer 260 in the light emitting device according to the first embodiment.

The third wavelength conversion layer 270 may convert part of the light emitted from the second wavelength conversion layer 260 into light having a different wavelength from that of the light emitted from the second wavelength conversion layer 260.

In the figure, the first wavelength conversion layer 250 and the second wavelength conversion layer 260 have the same size, and the third wavelength conversion layer 270 has a smaller size than the second wavelength conversion layer 260 But is not limited thereto. 3, the second wavelength conversion layer 260 may be larger than the first wavelength conversion layer 250, and the third wavelength conversion layer 270 may be larger than the second wavelength conversion layer 250. For example, Layer 260 may be larger. Accordingly, the sizes of the first to third wavelength conversion layers 250, 260, and 270 can be variously designed and changed.

Each of the first to third wavelength conversion layers 250, 260, and 270 includes a fluorescent material and a light transmitting material.

Transparent materials of each of the first to third wavelength conversion layers 250, 260, and 270 may be glass or ceramic.

At least one of the light-transmitting materials of the first to third wavelength conversion layers 250, 260, and 270 may be a ceramic. Concretely, a combination like the following Examples 1) to 6) is possible.

Example. 1) The transmissive material of the first wavelength conversion layer 250 may be glass, the transmissive material of the second wavelength conversion layer 260 may be glass, and the transmissive material of the third wavelength conversion layer 270 may be ceramics.

Example. 2) The transmissive material of the first wavelength conversion layer 250 may be glass, the transmissive material of the second wavelength conversion layer 260 may be ceramics, and the transmissive material of the third wavelength conversion layer 270 may be glass.

Example. 3) The transmissive material of the first wavelength conversion layer 250 may be ceramic, the transmissive material of the second wavelength conversion layer 260 may be glass, and the transmissive material of the third wavelength conversion layer 270 may be glass.

Example. 4) The transmissive material of the first wavelength conversion layer 250 may be glass, the transmissive material of the second wavelength conversion layer 260 may be ceramics, and the transmissive material of the third wavelength conversion layer 270 may be ceramics.

Example. 5) The transmissive material of the first wavelength conversion layer 250 may be ceramic, the transmissive material of the second wavelength conversion layer 260 may be glass, and the transmissive material of the third wavelength conversion layer 270 may be ceramics.

Example. 6) The transmissive material of the first wavelength conversion layer 250 may be ceramic, the transmissive material of the second wavelength conversion layer 260 may be ceramics, and the transmissive material of the third wavelength conversion layer 270 may be glass.

Example 2), 3) and 6) in which the third wavelength conversion layer 270 is glass in the above Examples 1) to 6) are the same as Example 3) and 6) in which the third wavelength conversion layer 270 is a ceramic. 1), 4) and 5). The reason is that since the refractive index of ceramics is larger than that of air or glass, the amount of light extracted is larger when the third wavelength conversion layer 270 is glass than when the third wavelength conversion layer 270 is a ceramic to be.

The first to third wavelength conversion layers 250, 260, and 270 may have different fluorescent materials. For example, the fluorescent material of the first wavelength conversion layer 250 includes a yellow fluorescent material, the fluorescent material of the second wavelength conversion layer 260 includes a green fluorescent material, and the fluorescent material of the third wavelength conversion layer 270 The material may comprise a red phosphor. However, the present invention is not limited to this. The fluorescent material of the first wavelength conversion layer 250 is one of the yellow, green, and red phosphors, the fluorescent material of the second wavelength conversion layer 260 is one of the remaining two phosphors, And the fluorescent material of the third wavelength conversion layer 270 may be the other one.

Thus, if the first to third wavelength conversion layers 250, 260, and 270 of the light emitting device according to the second embodiment shown in Figs. 7 to 8 have different fluorescent materials, the light emission according to the second embodiment The device may have a wider color temperature range than the light emitting device according to the first embodiment shown in Figs. More specifically, the description will be made with reference to Fig.

9 is a color coordinate diagram for explaining the effect of the light emitting device according to the second embodiment shown in Fig.

9, a straight line A is a straight line of a color coordinate by the first wavelength conversion layer 250, a straight line B is a straight line of a color coordinate by the second wavelength conversion layer 260, and a straight line C is a straight line by a third wavelength conversion layer 270 Is a straight line of color coordinates.

9, it is easy to control the designer's desired color temperature in the range between A straight line, B straight line and C straight line when there are three or more wavelength conversion layers. In the range between A straight line, B straight line and C straight line, The desired color temperature can be determined, and the color temperature range is further enlarged than that shown in Fig.

In the light emitting device according to the second embodiment shown in Figs. 7 to 8, since the first to third wavelength conversion layers 250, 260, and 270 have different fluorescent materials, There is an advantage that light having better color rendering property can be emitted from the light emitting device according to the first embodiment shown in the drawing.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

110: substrate
120: first electrode layer
130: second electrode layer
140: Light emitting element
150: first wavelength conversion layer
160, 160 ': a second wavelength conversion layer

Claims (10)

Board;
A light emitting element disposed on the substrate;
A first wavelength conversion layer disposed on the light emitting element and converting part of the light emitted from the light emitting element into light having a wavelength different from a wavelength of the light emitted from the light emitting element; And
A second wavelength conversion layer disposed on the first wavelength conversion layer and converting part of the light emitted from the first wavelength conversion layer into light having a wavelength different from a wavelength of the light emitted from the first wavelength conversion layer; / RTI >
Wherein the first wavelength conversion layer and the second wavelength conversion layer comprise a light-transmitting material,
Wherein at least one of the light transmitting material of the first wavelength conversion layer and the light transmitting material of the second wavelength conversion layer is a ceramic. The method according to claim 1,
Wherein the light-transmitting material of the second wavelength conversion layer is glass. 3. The method of claim 2,
Wherein each of the first and second wavelength conversion layers includes a fluorescent material,
Wherein the fluorescent materials of the first and second wavelength conversion layers are different from each other. The method of claim 3,
Wherein the fluorescent material of the first wavelength conversion layer comprises a red phosphor,
And the fluorescent material of the second wavelength conversion layer comprises a yellow phosphor. The method according to claim 1,
The light emitting device includes a second wavelength conversion layer disposed on the second wavelength conversion layer and configured to convert part of the light emitted from the second wavelength conversion layer into light having a wavelength different from a wavelength of the light emitted from the second wavelength conversion layer 3 wavelength conversion layer,
Wherein the third wavelength conversion layer comprises a light-transmitting material,
Wherein the light-transmitting material of the third wavelength conversion layer is glass or ceramic. 6. The method of claim 5,
Wherein each of the first through third wavelength conversion layers includes a fluorescent material,
Wherein the fluorescent materials of the first to third wavelength conversion layers are different from each other. 7. The method according to any one of claims 1 to 6,
Wherein the light emitting element includes an upper surface including a light emitting surface for emitting light,
The area of the lower surface of the first wavelength conversion layer is larger than the area of the light emitting surface of the light emitting element and is smaller than the area of the upper surface of the light emitting element. 7. The method according to any one of claims 1 to 6,
Wherein the light emitting device includes a first electrode layer and a second electrode layer disposed on the substrate,
Wherein the light emitting element is disposed on the first electrode layer,
Wherein the light emitting element and the second electrode layer are electrically connected through at least two wires. Board;
A light emitting element disposed on the substrate;
A first wavelength conversion layer disposed on the light emitting element, the first wavelength conversion layer including a first fluorescent material; And
And a second wavelength conversion layer disposed on the first wavelength conversion layer and including a second fluorescent material,
Wherein the first wavelength conversion layer includes a plurality of wavelength conversion layers,
Wherein each of the plurality of wavelength conversion layers includes one of glass and ceramic,
Wherein the second wavelength conversion layer comprises glass. 10. The method of claim 9,
Wherein the first fluorescent material is different from the second fluorescent material.

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