LIGHT EMITTING DEVICE AND LIGHTING SYSTEM HAVING THE SAME

Abstract

A light emitting device including a first light emitting portion that emits white light at a color temperature of 6000K or more and a second light emitting portion that emits white light at a color temperature of 3000K or less, which include light emitting diode chips and phosphors and are independently driven.

Claims

1. A light emitting device, comprising: a base plate; and a plurality of dots disposed on the base plate, each dot comprising: a first light emitting portion comprising a first light emitting chip and a first phosphor configured to combine with the first light emitting chip to emit a first light spectrum; and a second light emitting portion comprising a second light emitting chip and a second phosphor configured to combine with the second light emitting chip to emit a second light spectrum, wherein: the first light emitting portions and the second light emitting portions are disposed on the base plate; the first light emitting chip and the second light emitting chip are configured to emit light with a peak wavelength of blue or ultraviolet (UV) light; a relative intensity of light at the peak wavelength of the first light emitting chip in an emission spectrum of the first light emitting portion is higher than a relative intensity of light at the peak wavelength of the second light emitting chip in an emission spectrum of the second light emitting portion; and the relative intensity of light at the peak wavelength of the second light emitting chip in the emission spectrum of the second emitting portion is lower than a maximum intensity of light within a wavelength range of green light in the emission spectrum of the second emitting portion or a maximum intensity of light within wavelength range of red light in the emission spectrum of the second emitting portion.

2. The light emitting device of claim 1, wherein the first light spectrum comprises a highest peak in a blue wavelength region emitted from the first light emitting chip and a second highest peak in a green wavelength region emitted from the first phosphor.

3. The light emitting device of claim 1, wherein the second light spectrum comprises a highest peak in a red wavelength region emitted from the second phosphor and a second highest peak in a green wavelength region emitted from the second phosphor.

4. The light emitting device of claim 1, wherein each of the first and second phosphors comprise a green phosphor and a red phosphor.

5. The light emitting device of claim 4, wherein peak wavelengths of the first and second light emitting chips are in a range of 405-456 nm, the green phosphor has a peak wavelength in a range of 505-556 nm, and the red phosphor has a peak wavelength equal to or greater than 593 nm.

6. The light emitting device of claim 4, wherein the first light emitting portion and the second light emitting portion have different peak wavelengths.

7. The light emitting device of claim 5, wherein a light spectrum comprises the first light spectrum having a highest peak in a blue wavelength region, a second highest peak in a green wavelength region, and a third highest peak in a red wavelength region.

8. The light emitting device of claim 7, wherein the light emitting device generates the first light spectrum with the first light emitting portion without use of the second light emitting portion.

9. The light emitting device of claim 5, wherein a light spectrum comprises the second light spectrum having a highest peak in a red wavelength region, a second highest peak in a green wavelength region, and a third highest peak in a blue wavelength region.

10. The light emitting device of claim 9, wherein the light emitting device generates the second light spectrum with the second light emitting portion without use of the first light emitting portion.

11. The light emitting device of claim 1, wherein the first light emitting portion and the second light emitting portion have a color temperature difference of at least 3000K.

12. The light emitting device of claim 1, wherein the first light emitting portion and the second light emitting portion are separated by a wall disposed on the base plate.

13. A light emitting device, comprising: a base plate; and a plurality of dots disposed on the base plate, each dot comprising: a first light emitting portion comprising a first light emitting chip and a first phosphor configured to combine with the first light emitting chip to emit daylight having a color temperature equal to or greater than 6000K; and a second light emitting portion comprising a second light emitting chip and a second phosphor configured to combine with the second light emitting chip to emit warm white light having a color temperature less than or equal to 3000K, wherein: the first light emitting portions and the second light emitting portions are disposed on the base plate; the first light emitting portion and the second light emitting portion are arranged alternately with each other; the first light emitting chip and the second light emitting chip are configured to emit light with a peak wavelength of blue or ultraviolet (UV) light; a relative intensity of light at the peak wavelength of the first light emitting chip in an emission spectrum of the first light emitting portion is higher than a relative intensity of light at the peak wavelength of the second light emitting chip in an emission spectrum of the second light emitting portion; and the relative intensity of light at the peak wavelength of the second light emitting chip in the emission spectrum of the second emitting portion is lower than a maximum intensity of light within a wavelength range of green light in the emission spectrum of the second emitting portion or a maximum intensity of light within wavelength range of red light in the emission spectrum of the second emitting portion.

14. The light emitting device of claim 13, wherein a first light spectrum comprises a highest peak in a blue wavelength region emitted from the first light emitting chip and a second highest peak in a green wavelength region emitted from the first phosphor.

15. The light emitting device of claim 14, wherein a second light spectrum comprises a highest peak in a red wavelength region emitted from the second phosphor and a second highest peak in a green wavelength region emitted from the second phosphor.

16. The light emitting device of claim 15, wherein each of the first and second phosphors comprise a green phosphor and a red phosphor.

17. The light emitting device of claim 16, wherein the peak wavelength of the first light emitting chip is in a range of 405-456 nm, the green phosphor has a peak wavelength in a range of 505-556 nm, and the red phosphor has a peak wavelength equal to or greater than 593 nm.

18. The light emitting device of claim 16, wherein the peak wavelength of the second light emitting chip is in a range of 405-456 nm, the green phosphor has a peak wavelength in a range of 505-556 nm, and the red phosphor has a peak wavelength equal to or greater than 593 nm.

19. The light emitting device of claim 18, wherein the light emitting device generates the second light spectrum with the second light emitting portion without use of the first light emitting portion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG. 1 is a conceptual block diagram illustrating a light emitting device according to a first embodiment of the present invention.

[0045] FIG. 2 is a concept block diagram illustrating a light emitting device according another embodiment of the present invention.

[0046] FIGS. 3 and 4 are graphs illustrating an embodiment of first and second controller parts respectively.

[0047] FIGS. 5 and 6 are graphs illustrating another embodiment of first and second controller parts respectively.

[0048] FIGS. 7 and 8 are graphs showing light spectrum of the light emitting device according to a first embodiment.

[0049] FIGS. 9 and 10 are graphs showing light spectrum of the light emitting device according to a second embodiment.

[0050] FIGS. 11 and 12 are graphs showing light spectrum of the light emitting device according to a third embodiment.

[0051] FIGS. 13 to 18 are sectional views of the light emitting devices applying to different structures.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

[0052] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. These embodiments are provided only for illustrative purposes and for full understanding of the scope of the present invention by those skilled in the art. Accordingly, the present invention is not limited to the embodiments but may be implemented into different forms. In the drawings, the width, length, thickness and the like of each component may be exaggerated for convenience and clarity of illustration. Throughout the drawings, like components are designated by like reference numerals.

[0053] A light emitting device according to the present invention is characterized by a first light emitting portion that emits white light with a relatively high color temperature within a single package, a second light emitting portion that emits light with a relatively low color temperature, and possibility of operating independently from the first light emitting portion and the second light emitting portion.

[0054] The first light emitting portion emits white light at a color temperature of 6000K or more, which is known as daylight. The second light emitting portion emits white light at a color temperature of 3000K or less, which is known as warm white.

[0055] The first and second light emitting portions include a light emitting diode chip and phosphor. The white light with a desired light spectrum and color temperature can be realized by combination of blue light or UV light emitted from a light emitting diode chip and wavelength-converted light by phosphor.

[0056] A light emitting diode chip and phosphor forming the first light emitting portion or the second light emitting portion can be diversely comprised. For example, the first light emitting portion or the second light emitting portion can include a single blue light emitting diode chip and a phosphor with yellow emission. The white light is realized by combination of blue light emitted from a light emitting diode chip and wavelength-converted yellow light by phosphor. Further, the first light emitting portion or the second light emitting portion can include a single blue light emitting diode chip, a phosphor with green emission and a phosphor with orange emission. The white light is realized by combination of blue light emitted from a light emitting diode chip and wavelength-converted green and orange light by phosphors. In this case, there is an advantage in that the color rendering index is more improved than that of the white light realized by combination of blue light emitted from a light emitting diode chip and wavelength-converted yellow light by phosphor. Namely, the color rendering index can be improved by using a light emitting diode chip and a plurality of phosphor materials with different emission peaks.

[0057] It is preferable to use a blue light emitting diode chip or a UV light emitting diode chip as the aforementioned light emitting diode chips.

[0058] The aforementioned phosphors are characterized by using phosphor materials with different emission peaks, for example silicate phosphor with emission peaks from green to red. The white light with various light spectrums and color temperatures can be realized by making a variety of colors out of light emitted from a light emitting diode chip. In case of using a plurality of phosphor materials, an influence of phosphor materials on each other can be minimized by using the same series of phosphor materials.

[0059] The aforementioned phosphor materials include aluminates, silicates, oxynitrides, antimonates, germanates, or phosphates. Particularly, use of phosphor materials containing Pb or Cu causes the high stability and excellent photoexcitation.

[0060] The aluminate phosphors include phosphor materials expressed by the following chemical formula 1, 2 and 3.

a(M′O).Math.b(M″.sub.2O).Math.c(M″X).Math.d Al.sub.2O.sub.3.Math.e(M′″O).Math.f(M″″.sub.2O.sub.3).Math.g(M′″″.sub.oO.sub.p).Math.h(M″″″.sub.xO.sub.y)  <Chemical Formula 1>

[0061] wherein the metal M′ is one or more elements from the group of Pb, Cu

[0062] wherein the metal M″ is one or more monovalent elements from the group Li, Na, K, Rb, Cs, Au, Ag,

[0063] wherein M.sup.III is one or more divalent elements from the group of Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn,

[0064] wherein the metal M.sup.IV is one or more trivalent elements from the group of Sc, B, Ga, In,

[0065] wherein the metal M.sup.V is one or more elements from the group of Si, Ge, Ti, Zr, Mn, V, Nb, Ta, W, Mo,

[0066] wherein the metal M.sup.VI is at least one or more elements from the group of Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu

[0067] wherein X is one or more elements from the group of F, Cl, Br, I,

[0068] and wherein a range of a, b, c, d, e, f, g, o, p, h, x and y is 0<a≤2, 0≤b≤2, 0≤c≤2, 0≤d≤8, 0≤e≤4, 0≤f≤3, 0≤g≤8, 1≤o≤2, 1≤p≤5, 0≤h≤2, 1≤x≤2 and 1≤y≤5 respectively.

a(M.sup.IO)b(M.sup.II.sub.2O)c(M.sup.IIIX)4-a-b-c(M.sup.IIIO)7(Al.sub.2O.sub.3)d(B.sub.2O.sub.3)e(Ga.sub.2O.sub.3)f(SiO.sub.2)g(GeO.sub.2)h(M.sup.IV.sub.xO.sub.y)  <Chemical Formula 2>

[0069] wherein M.sup.I is one or more elements from the group of Pb, Cu,

[0070] wherein M.sup.II is one or more monovalent element from Li, Na, K, Rb, Cs, Au, Ag,

[0071] wherein M.sup.III is one or more divalent elements from the group of Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn,

[0072] wherein M.sup.IV is one or more elements from the group of Bi, Sn, Sb, Sc, Y, La, In,

[0073] Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,

[0074] wherein X is one ore more elements from the group F, Cl, Br, I,

[0075] and wherein a range of a, b, c, d, e, f, g, h, x and y is 0<a≤4, 0≤b≤2, 0≤c≤2, a+b+c≤4, 0≤d≤1, 0≤e≤1, 0≤f≤1, 0≤g≤1, 0≤h≤0.5, 1≤x≤2 and 1≤y≤5 respectively.

a(M.sup.IO)b(M.sup.IIO)c(Al.sub.2O.sub.3)d(M.sup.III.sub.2O.sub.3)e(M.sup.IVO.sub.2)f(M.sup.V.sub.xO.sub.y)  <Chemical Formula 3>

[0076] wherein M.sup.I is at least one or more elements from the group of Pb, Cu,

[0077] wherein M.sup.II is at least one or more divalent elements from the group of Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn,

[0078] wherein M.sup.III is one or more elements from the group of B, Ga, In,

[0079] wherein M.sup.IV is one or more elements from the group of Si, Ge, Ti, Zr, Hf,

[0080] wherein M.sup.V is at least one or more elements from the group of Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,

[0081] and wherein a range of a, b, c, d, e, f, x and y is 0<a≤1, 0≤b≤2, 0≤c≤8, 0≤d≤1, 0≤e≤1, 0≤f≤2, 1≤x≤2 and 1≤y≤5 respectively.

[0082] The silicate phosphors include phosphor materials expressed by the following chemical formula 4.

a(M.sup.IO)b(M.sup.IIO)c(M.sup.IIIX)d(M.sup.III.sub.2O)e(MI.sup.V.sub.2O.sub.3)f(M.sup.V.sub.oO.sub.p)g(SiO.sub.2)h(M.sup.VI.sub.xO.sub.y)  <Chemical Formula 4>

[0083] wherein M.sup.I is one or more elements from the group of Pb, Cu,

[0084] wherein M.sup.II is one or more divalent elements from the group of Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn,

[0085] wherein M.sup.III is one or more monovalent elements from the group Li, Na, K, Rb, Cs, Au, Ag,

[0086] wherein M.sup.IV is one or more from the group Al, Ga, In, B,

[0087] wherein M.sup.V is one or more elements from the group Ge, V, Nb, Ta, W, Mo, Ti, Zr, Hf, P,

[0088] wherein M.sup.VI is at least one or more elements from the group of Bi, Sn, Sb, Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,

[0089] wherein X is at least one ore more elements from the group F, Cl, Br, I

[0090] and wherein a range of a, b, c, d, e, f, g, h, o, p, x and y is 0<a≤2, 0≤b≤8, 0≤c≤4, 0≤d≤2, 0≤e≤2, 0≤f≤2, 0≤g≤10, 0≤h≤5, 1≤o≤2, 1≤p≤5, 1≤x≤2 and 1≤y≤5 respectively.

[0091] The antimonate phosphors include phosphor materials expressed by the following chemical formula 5.

a(M.sup.IO)b(M.sup.II.sub.2O)c(M.sup.IIX)d(Sb.sub.2O.sub.5)e(M.sup.IIIO)f(M.sup.IV.sub.xO.sub.y)  <Chemical Formula 5>

[0092] wherein M.sup.I is one or more elements from the group of Pb, Cu,

[0093] wherein M.sup.II is one or more monovalent elements from the group Li, Na, K, Rb, Cs, Au, Ag,

[0094] wherein the metal M.sup.III is one or more divalent elements from the group of Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn,

[0095] wherein the metal M.sup.IV is at least one or more elements from the group of Bi, Sn, Sc, Y, La, Pr, Sm, Eu, Tb, Dy, Gd,

[0096] wherein X is at least one ore more elements from the group F, Cl, Br, I,

[0097] and wherein a range of a, b, c, d, e, f, x and y is 0<a≤2, 0≤b≤2, 0≤c≤4, 0≤d≤8, 0≤e≤8, 0≤f≤2, 1≤x≤2 and 1≤y≤5 respectively.

[0098] The germanate phosphors include phosphor materials expressed by the following chemical formula 6.

a(M.sup.IO)b(M.sup.II.sub.2O)c(M.sup.IIX)dGeO.sub.2e(M.sup.IIIO)f(M.sup.IV.sub.2O.sub.3)g(M.sup.V.sub.oO.sub.p)h(M.sup.VI.sub.xO.sub.y)  <Chemical Formula 6>

[0099] wherein M.sup.I is one or more elements from the group of Pb, Cu

[0100] wherein M.sup.II is one or more monovalent elements from the group Li, Na, K, Rb, Cs, Au, Ag,

[0101] wherein M.sup.III is one or more divalent elements from the group of Be, Mg, Ca, Sr, Ba, Zn, Cd,

[0102] wherein M.sup.IV is one or more trivalent elements from the group of Sc, Y, B, Al, Ga, In, La,

[0103] wherein M.sup.V is one or more element from the group of Si, Ti, Zr, Mn, V, Nb, Ta, W, Mo,

[0104] wherein M.sup.VI is at least one or more elements from the group of Bi, Sn, Pr, Sm, Eu, Gd, Dy,

[0105] wherein X is at least one ore more elements from the group F, Cl, Br, I,

[0106] and wherein a range of a, b, c, d, e, f, g, h, o, p, x and y is 0<a≤2, 0≤b≤2, 0≤c≤10, 0≤d≤10, 0≤e≤14, 0≤f≤14, 0≤g≤10, 0≤h≤2, 1≤o≤2, 1≤p≤5, 1≤x≤2 and 1≤y≤5 respectively.

[0107] The phosphate phosphors include phosphor materials expressed by the following chemical formula 7.

a(M.sup.IO)b(M.sup.II.sub.2O)c(M.sup.IIX)dP.sub.2O.sub.5e(M.sup.IIIO)f(M.sup.IV.sub.2O.sub.3)g(M.sup.VO.sub.2)h(M.sup.VI.sub.xO.sub.y)  <Chemical Formula 7>

[0108] wherein M.sup.I is one or more elements from the group of Pb, Cu,

[0109] wherein M.sup.II is one or more monovalent elements from the group Li, Na, K, Rb, Cs, Au, Ag,

[0110] wherein M.sup.III is one or more divalent elements from the group of Be, Mg, Ca, Sr, Ba, Zn, Cd, Mn,

[0111] wherein M.sup.IV is one or more trivalent elements from the group of Sc, Y, B, Al, La, Ga, In,

[0112] wherein M.sup.V is one or more element from the group of Si, Ge, Ti, Zr, Hf, V, Nb, Ta, W, Mo,

[0113] wherein M.sup.VI is at least one or more elements from the group of Bi, Sn, Pr, Sm, Eu, Gd, Dy, Ce, Tb,

[0114] wherein X is at least one ore more elements from the group F, Cl, Br, I,

[0115] and wherein a range of a, b, c, d, e, f, g, h, x and y is 0<a≤2, 0≤b≤12, 0≤c≤16, 0≤d≤3, 0≤e≤5, 0≤f≤3, 0≤g≤2, 0≤h≤2, 1≤x≤2 and 1≤y≤5 respectively.

[0116] FIG. 1 is a conceptual block diagram illustrating a light emitting device according to a first embodiment of the present invention.

[0117] Referring to FIG. 1, a light emitting device includes a first light emitting portion that emits white light at a color temperature of 6000K or more, second light emitting portion that emits white light at a color temperature of 3000K less, and the said first light emitting portion and second light emitting portion are characterized by independent driving. In this kind of a light emitting device, since a plurality of light emitting portions in a single package (A) can have its own electrical connection, the said first light emitting portion and second light emitting portion can be driven independently. For example, in case that only first light emitting portion is powered on, white light at a color temperature of 6000K or more (daylight) can be realized, and in case that only second light emitting portion is powered on, white light at a color temperature of 3000K or less (warm white) can be realized. Moreover, in case that the first light emitting portion and second light emitting portion are powered on together, white at with a color temperature range in between 3000K and 6000K can be realized by combination of the white light from the first light emitting portion and the second light emitting portion. Therefore, a light emitting device can realize white light with the high CRI, variable spectrum and color temperature by selective driving of a first light emitting device and a second light emitting device. Since a light emitting device according to the present invention can realize variable spectrum and color temperature of white light, it is advantageous that it can be applied variously in desired atmosphere and uses with only single package (A). For instance, driving a first light emitting portion, which emits white light at a color temperature of 6000K or more (daylight) in the daytime, activity and concentration of human brain can be improved, and driving second light emitting portion, which emits white light at a color temperature of 3000K or less (warm white) in the night time, it helps people to have more peaceful and comfortable rest. Especially, it has effect of improving health by controlling wavelength and color temperature of the light appropriately according to circadian function of effects of human being.

[0118] FIG. 2 is a concept block diagram illustrating a light emitting device according to another embodiment of the present invention.

[0119] Referring to FIG. 2, a light emitting device comprises a first light emitting portion that emits white light at a color temperature of 6000K or more, a second light emitting portion that emits white light at a color temperature of 3000K or less, a first controller part connected to the said first light emitting portion, and a second controller part connected to the said second light emitting portion. And the first and second controller parts are characterized by control of input power from the outside to the first and second light emitting portions.

[0120] The said first and second controller part are to control each input voltage to the first and second light emitting portion, for example, the said first and second controller parts control the input voltage from the power by the time and output. So the said first and second controller parts can include timer and voltage controller circuit. That is, input voltage to the controller part from the power outside is controlled through timer and voltage controller circuit by the time then it is passed to the first and second light emitting portions.

[0121] FIGS. 3 and 4 are graphs illustrating an embodiment of the first and second controller parts respectively.

[0122] As shown in FIG. 3, the first controller part passes the voltage from the power outside for first 12 hours of the day, and blocks the voltage for remaining 12 hours of the day. In contrast, the second controller part blocks the voltage for first 12 hours of the day as shown in the FIG. 4, and passes the voltage for remaining 12 hours of the day. That is, for 12 hours of a day, power is delivered to only the first light emitting portion for driving, and for remaining 12 hours of a day, power is delivered to only the second light emitting portion for driving.

[0123] Operation of light emitting device is explained as follows. Power is impressed to the first and second controller parts, and the first and second controller parts control the voltage by the time and deliver to the first and second light emitting portion. As mentioned above, voltage impressed from power outside is delivered to only the first light emitting portion for 12 hours of a day, and it is delivered to only the second light emitting portion for remaining 12 hours of a day.

[0124] That is, for 12 hours of a day, for example, white light at a color temperature of 6000K or more (daylight) can be realized by driving only the first light emitting portion in the daytime, and for remaining 12 hours of a day, for example, white light at a color temperature of 3000K or less (warm white) can be realized by driving only the second light emitting portion.

[0125] The aforementioned is showing an example of power on/off to the first and second light emitting portions, but it is not limited to, it can be applied in various ways. For instance, as it is shown in FIGS. 5 and 6, luminous intensity of the first and second light emitting portions can be increased or decreased as the voltage is increased or decreased by the time. Accordingly, a color temperature of white light emitted from a light emitting device can be increased or decreased gradually.

[0126] Since such a light emitting device can control the operation of the first and second light emitting devices through the first and second controller parts, it can be applied in various ways as desired.

[0127] So that, a light emitting device of which color temperature is controlled automatically can be produced without a separated input by the time. For instance, a light emitting device can be formed to realize a relatively high color temperature during the daytime, and a relatively low color temperature during the nighttime. Especially, it has effect of improving health by controlling wavelength and a color temperature of the light appropriately according to the circadian rhythm of humans.

[0128] The aforementioned embodiment explained a controller part, which controls voltage by the time, but it is not limited to, the said controller part can include an additional separate input part, so that, it can be formed to adjust a color temperature as user's desire. Moreover, the aforementioned embodiment showed that power is impressed to the first and second controller parts at the same time, but it is not limited to, the said first and second controller parts can be connected to separated power, and they can be driven independently. Furthermore, they can be formed to include only one controller, which can control the first and second light emitting portions together.

[0129] Since such a light emitting device can realize various spectrum and color temperature of white light, it is advantageous that it can be applied variously in desired atmosphere and uses with only single package (A). For instance, driving a first light emitting portion, which emits white light at a color temperature of 6000K or more (daylight) in the daytime, activity and concentration of human brain can be improved, and driving second light emitting portion, which emits white light at a color temperature of 3000K or less (warm white) in the night time, it helps people to have more peaceful and comfortable rest. Especially, it has effect of improving health by controlling wavelength and a color temperature of the light appropriately according to the circadian rhythm of humans.

[0130] Moreover, there is an effect of reducing cumbersome in procedure and the cost and increasing effective use of space, since it is formed by a single package, which has been comprised of a separated package to realize white light with various spectrum and color temperatures in prior art.

[0131] The present invention is described more specifically in the following examples.

Example 1

[0132] A first light emitting portion is comprised of a light emitting diode chip with wavelength of 456 nm (blue light), the phosphor consisting of Cu.sub.0.15Ba.sub.1.82Sr.sub.0.03Si.sub.0.99Ge.sub.0.01O.sub.4:Eu with peak emission of 515 nm, and the phosphor consisting of Cu.sub.0.05Sr.sub.1.72Ca.sub.0.23Si.sub.0.99Ge.sub.0.01O.sub.4:Eu with peak emission of 593 nm.

[0133] A second light emitting portion is comprised of a light emitting diode chip with wavelength of 452 nm, the phosphor consisting of Cu.sub.0.15Ba.sub.1.84Sr.sub.0.01Si.sub.0.99Zr.sub.0.01O.sub.4:Eu with peak emission of 508 nm, and the phosphor consisting of Cu.sub.0.05Sr.sub.1.85Ca.sub.0.10SiO.sub.4:Eu with peak emission of 605 nm.

[0134] FIG. 7 shows emission spectrum of the first light emitting portion and FIG. 8 shows emission spectrum of the second light emitting portion. As illustrated in the figure, luminous intensity of the first light emitting portion is relatively high in blue emission region, and luminous intensity of the second light emitting portion is relatively high in yellow or red emission region. That is, a color temperature of the first light emitting portion is relatively high and a color temperature of the second light emitting portion is relatively low.

[0135] The first light emitting portion of this embodiment has 9,500K of a color temperature with excellent color rendering index of 88. Moreover, the second light emitting portion has 2,640K of a color temperature with excellent color rendering index of 83.

[0136] So that, selective driving of first light emitting portion and second light emitting portion, white light with excellent color rendering index and various spectrum can be realized. For example, only driving the first light emitting portion in the daytime, white light with relatively high color temperature, 9,500K is realized, and only driving second light emitting portion in the nighttime, white light with relatively low color temperature, 2,640K is realized.

Example 2

[0137] A first light emitting portion is comprised of a light emitting diode chip with wavelength of 456 nm, the phosphor consisting of Cu.sub.0.15Ba.sub.1.82Sr.sub.0.03Si.sub.0.99Ge.sub.0.01O.sub.4:Eu with peak emission of 515 nm, and the phosphor consisting of Cu.sub.0.05Sr.sub.1.8Ca.sub.0.15SiO.sub.4:Eu with peak emission of 600 nm.

[0138] A second light emitting portion is comprised of a light emitting diode chip with wavelength of 456 nm, the phosphor consisting of Cu.sub.0.15Ba.sub.1.82Sr.sub.0.03Si.sub.0.99Ge.sub.0.01O.sub.4:Eu, with peak emission of 515 nm, and the phosphor consisting of Cu.sub.0.05Sr.sub.1.8Ca.sub.0.15SiO.sub.4:Eu with peak emission of 600 nm.

[0139] The phosphors mixing ratio of the first emitting portion is different from the phosphors mixing ratio of the second emitting portion, so that color temperature and color rendering index of the first emitting portion are different from them of the second emitting portion.

[0140] FIG. 9 shows light spectrum of the first light emitting portion and FIG. 10 shows light spectrum of the second light emitting portion. As shown in FIGS. 9 and 10, a color temperature of the first light emitting portion is relatively high and a color temperature of the second light emitting portion is relatively low.

[0141] The first light emitting portion of this embodiment has 8,800K of a color temperature with an excellent color rendering index of 92. Moreover, the second light emitting portion has 2,550K of a color temperature with an excellent color rendering index of 80.

[0142] The white light with an excellent color rendering index and various light spectrum and color temperatures can be realized by selective driving of first light emitting portion and second light emitting portion. For example, the white light with a color temperature of 8800K which is relatively high is rendered during the day by driving only the first light emitting portion, and the white light with a color temperature of 2550K which is relatively low is rendered during the night by driving only the second light emitting portion.

Example 3

[0143] A first light emitting portion is comprised of a light emitting diode chip that emits UV light with wavelength of 405 nm, the phosphor consisting of Cu.sub.0.02Ba.sub.2.8Sr.sub.0.2Mg.sub.0.98Si.sub.2O.sub.8:Eu with emission peak of 440 nm, the phosphor consisting of Cu.sub.0.15Ba.sub.1.84Sr.sub.0.01Si.sub.0.99Zr.sub.0.01O.sub.4:Eu with emission peak of 508 nm, the phosphor consisting of Cu.sub.0.02Ba.sub.0.98Sr.sub.0.98Ca.sub.0.02SiO.sub.4:Eu with emission peak of 565 nm, and the phosphor consisting of Cu.sub.0.15Mg.sub.0.85BaP.sub.2O.sub.7:Eu, Mn with emission peak of 630 nm.

[0144] A second light emitting portion is comprised of a light emitting diode chip that emits UV light with wavelength of 405 nm, the phosphor consisting of Cu.sub.0.02Ba.sub.2.8Sr.sub.0.2Mg.sub.0.98Si.sub.2O.sub.8:Eu with emission peak of 440 nm, the phosphor consisting of Cu.sub.0.15Ba.sub.1.82Sr.sub.0.03Si.sub.0.99Ge.sub.0.01O.sub.4:Eu with emission peak of 515 nm, the phosphor consisting of Cu.sub.0.05Sr.sub.1.72Ca.sub.0.23Si.sub.0.99Ge.sub.0.01O.sub.4:Eu with emission peak of 593 nm, and the phosphor consisting of Cu.sub.0.15Mg.sub.0.85BaP.sub.2O.sub.7:Eu, Mn with emission peak of 630 nm.

[0145] FIG. 11 shows light spectrum of the first light emitting portion and FIG. 12 shows light spectrum of the second light emitting portion. As shown in FIGS. 11 and 12, a color temperature of the first light emitting portion is relatively high and a color temperature of the second light emitting portion is relatively low.

[0146] The first light emitting portion of this embodiment has 8,800K of a color temperature with an excellent color rendering index of 88. Moreover, the second light emitting portion has 2600K of a color temperature with an excellent color rendering index of 95.

[0147] The white light with an excellent color rendering index and various light spectrum and color temperatures can be realized by selective driving of first light emitting portion and second light emitting portion. For example, the white light with a color temperature of 8800K which is relatively high is rendered during the day by driving only the first light emitting portion, and the white light with a color temperature of 2600K which is relatively low is rendered during the night by driving only the second light emitting portion.

[0148] FIGS. 13 to 17 show the light emitting devices applying to different structures according to the present invention.

[0149] Referring to FIG. 13, a light emitting device comprises a substrate (10), a first light emitting portion (200) and a second light emitting portion (300) mounted on the substrate (10).

[0150] The first light emitting portion (200) comprises a first light emitting diode chip (20) and a first phosphor (30). The first phosphor (30) mixed in thermoset resin(50) such as epoxy and silicon is disposed on the first light emitting diode chip (20). The first light emitting portion (200) renders white light at a color temperature of 6000K or more (daylight) by combination of light emitted from the first light emitting diode chip (20) and wavelength-converted light by the first phosphor (30).

[0151] Likewise, the second light emitting portion (300) comprises a second light emitting diode chip (60) and a second phosphor (70). The second phosphor (70) mixed in thermoset resin(90) such as epoxy and silicon is disposed on the second light emitting diode chip (60). The second light emitting portion (300) renders white light at a color temperature of 3000K or less (warm white) by combination of light emitted from the second light emitting diode chip (60) and wavelength-converted light by the second phosphor (70).

[0152] The substrate (10) can have a predetermined slope on the sidewalls of a cavity by forming a predetermined cavity wherein first and second light emitting portion (200, 300) are formed. Referring to FIG. 14, a light emitting device comprises the substrate (10) with the cavity (100), and the first light emitting portion (200) and the second light emitting portion (300) formed on the bottom of the cavity (100). The first light emitting portion (200) comprising the first light emitting diode chip (20) and the first phosphor (30) and the second light emitting portion (300) comprising the second light emitting diode chip (60) and the second phosphor (70) are formed on the bottom of the cavity (100). A compound (50, 90) of the first and second phosphor (30, 70) and thermoset resin is disposed on the first and second light emitting diode chips (20, 60). A predetermined slope of the sidewalls of the cavity (100) can maximize reflection of light emitted from the light emitting diode chips (20, 60) and increase luminescent efficiency. A molding portion (not shown) can be formed by filling the inside of the cavity (100) with transparent thermoset resin in order to protect the first and second light emitting portion (200, 300).

[0153] Further, a cavity corresponding to each of light emitting portions can be formed to separate the first light emitting portion (200) from the second light emitting portion (300). Referring to FIG. 15, a light emitting device comprises a substrate (10) with a plurality of cavities to separate light emitting portions (200, 300), and the first light emitting portion (200) and the second light emitting portion (300) separately formed on the bottom of the cavity. The first light emitting portion (200) is formed by mounting the first light emitting diode chip (20) on the bottom of a cavity (110) and filling the inside of the cavity (110) with a compound (50) of the first phosphor (30) and thermoset resin. The second light emitting portion (300) can be formed in the same way. At this time, reflection of light emitted from the light emitting diode chips (20, 60) can be maximized and luminescent efficiency can be increased by forming a predetermined slope of the sidewalls of each of the cavities.

[0154] A shape of the sidewalls of the cavity can be curved as well as straight. Referring to FIG. 16, a light emitting device comprises a substrate (10) wherein a cavity (120) is formed with the curved sidewalls, and the first light emitting portion (200) and the second light emitting portion (300) formed on the bottom of the cavity (120). Further, a partition (130) can be formed in a predetermined area of the bottom of the cavity (120) to separate the first light emitting portion (200) from the second light emitting portion (300). The partition (130) can be formed at the same height as the substrate (10) as shown in FIG. 15, or the partition can be formed at a lower height than the substrate (10) to separate the first light emitting portion (200) from the second light emitting portion (300) and a molding portion (140) filling the first and second light emitting portion (200, 300) together can be formed as shown in FIG. 16. In this case, it is advantageous to protect the first and second light emitting portion (200, 300) and make combination of light emitted from the first and second light emitting portion (200, 300) easy.

[0155] FIG. 17 shows an example of a light emitting device for efficiently emitting heat generated from the light emitting diode chips (20, 60). The light emitting device comprises a heat sink (160), the first light emitting portion (200) and the second light emitting portion (300) formed on the heat sink (160), a housing (150) surrounding the heat sink (160) lead frames (170, 180) protruding toward the outside of the housing, and a molding portion (190) filling the first and second light emitting portion (200, 300). At this time, use of excellent thermal conductive materials such as metal as a heat sink (160) can make it more efficient to emit heat generated from the light emitting diode chips (20, 60).

[0156] The heat sink (160) includes a protruding portion corresponding to each of the light emitting portions (200, 300) to make it easy to dispose a compound (50, 90) of the phosphor (30, 70) and thermoset resin on the light emitting diode chips (20, 60), but is not limited to. Further, a light emitting portion may be formed on a plane of the heat sink or on the bottom of the cavity of a heat sink.

[0157] In the aforementioned description, the first and second light emitting portions consist of a light emitting diode chip each, but is not limited to. The first and second light emitting portions may consist of a plurality of light emitting diode chips.

[0158] As the above, the present invention can be applied to various products as well as illumination. A number of light emitting diodes from 50 to 80 are needed to apply to illumination. Accordingly, packages manufactured with different structures may be mounted on a substrate or a number of light emitting diode chips may be mounted directly on a substrate.

[0159] As shown FIG. 18, a number of dots (500) are formed on a substrate (400) and each of dots (500) can comprise the first light emitting portion and the second light emitting portion. That is, each of dots (500) can render daylight and warm white, but is not limited to. Each of dots (500) can include either the first light emitting portion or the second light emitting portion. A dot including the first light emitting portion and a dot including the second light emitting portion may be arranged alternately with each other, or a group of dots including the first light emitting portion and a group of dots second light emitting portion may be arranged separately from each other. Dots can be arranged in various forms according to convenience of process or a desired purpose.

[0160] Hereinafter, preferred embodiments of the present invention have been described, but these embodiments are provided only for illustrative purposes and for full understanding of the scope of the present invention by those skilled in the art. Accordingly, the present invention is not limited to the embodiments but may be implemented into different forms.