KR20170029234A - Light emitting device - Google Patents

Abstract

The present invention relates to a light emitting device, and specifically, to a light emitting device including a light emitting diode (LED). According to the present invention, the light emitting device comprises: an LED; a first fluorescent body excited by light emitted from the LED to emit light of which a central wavelength is in a band of 520 to 550 nm; and a second fluorescent body excited by the light emitted from the LED to emit light of which a central wavelength is in a band of 560 to 560 nm. Moreover, the light emitting device additionally comprises at least one of a third fluorescent body excited by the light emitted from the LED to emit light of which a central frequency is in a band of 500 to 520 nm, and a fourth fluorescent body excited by the light emitted from the LED to emit light of which a central frequency is in a band of 620 to 660 nm.

Description

Light emitting device

The present invention relates to a light emitting device, and more particularly, to a light emitting device including a light emitting diode.

BACKGROUND ART [0002] Light emitting diodes (LEDs) are one of the next-generation light emitting device candidates that can replace fluorescent light, which is one of the most typical conventional lighting.

LEDs have less power consumption than conventional light sources, and unlike fluorescent lamps, they do not contain mercury and can be said to be environmentally friendly. In addition, it has a longer life span and faster response time than conventional light sources.

Such an LED can be used with a phosphor that emits light of various colors by absorbing light emitted from the LED. Such phosphors can usually emit yellow, green and red light.

The white LED is currently fabricated with a blue LED and a phosphor that converts the emission wavelength. As the use range of such a white LED becomes larger, a more efficient LED is required. For this purpose, improvement of the luminous efficiency of the phosphor is required. In addition, there is a growing demand for more reliable LEDs.

A YAG (Yttrium Aluminum Garnet) phosphor represented by US Pat. No. 5,999,925, which is an oxide phosphor, is known as a yellow phosphor. However, such a YAG phosphor has poor thermal stability. When the YAG phosphor has a high temperature, Can cause problems. Further, there is a problem that the luminous color tone is limited and the reproduction range of the color is narrow, and the phosphor absorbs a part of the blue LED light.

Further, oxide phosphors and silicate phosphors are known as yellow to green phosphors, but they have a relatively low thermal stability and poor moisture resistance, which may adversely affect the reliability of the LED package.

Accordingly, it is required to develop a phosphor with high efficiency and high reliability that can produce white light together with an LED.

Furthermore, as the blue emission LED becomes higher in output, the wavelength can be shifted to the short wavelength side. Accordingly, development of a yellow emission phosphor having a high excitation efficiency even in a short wavelength is required.

In addition, when a white light is used together with an LED, development of a phosphor excellent in color rendering characteristics is required.

The present invention provides a light emitting device having high efficiency and high color rendering property in a light emitting device.

According to a first aspect of the present invention, there is provided a light emitting device comprising: a light emitting element; A first phosphor that is excited by light emitted from the light emitting device and emits light having a center wavelength in a range of more than 520 nm to 550 nm; And a second phosphor which is excited by light emitted from the light emitting device and emits light having a center wavelength in a range of 560 to 600 nm, the second phosphor being excited by the light emitted from the light emitting device, A third phosphor that emits light positioned in a band of 520 nm and a fourth phosphor that emits light having a center wavelength in the range of 620 to 660 nm by being excited by the light emitted from the light emitting device, .

Here, the first phosphor is BaSi ₄ N ₇ : Eu, Ba ₃ Si ₆ O ₁₂ N ₂ : Eu, CaSi ₂ O ₂ N ₂ : Eu, SrYSi ₄ N ₇ : Eu, SiAlON (Ca-alpha-SiAlON: Yb), LuAG (Lu ₃ Al ₅ O ₁₂ : Ce), and SrSi ₂ O ₂ N ₂ : Eu.

Here, the first phosphor may have an amount of 50.6 to 67.7 wt% based on 100 wt% of the sum of the first to fourth phosphors.

The second phosphor is, α-type SiAlON having Li of a metal component (Li-α-SiAlON: Eu ), α -type SiAlON having the Ca of a metal component (Ca-α-SiAlON: Eu ) and Ba ₂ Si ₅ And N ₈ : Eu.

Here, the second phosphor is represented by the following formula (1)

≪ Formula 1 >

M and n may satisfy at least one of 0? M? 2 and 0? N? 1.

Here, the second phosphor may have a content of 16.7 to 28.7 wt%, assuming that the sum of the first to fourth phosphors is 100 wt%.

Here, the third phosphor, BaSi may include at least one of the _{2 O 2 N 2, BaAl 2} O 4 and SrAl ₂ O _4.

Here, the third phosphor may have a content of 21.4 to 27.5 wt% based on 100 wt% of the sum of the first to fourth phosphors.

Herein, the fourth fluorescent material is at least one selected from the group consisting of CaAlSiN ₃ : Eu, (Sr, Ca) AlSiN ₃ : Eu, Sr ₂ Si ₅ N ₈ : Eu, K ₂ SiF ₆ : Mn, La ₃ Si ₆ N ₁₁ : Ce, SrAlSiN ₃ Eu, SrCN ₂ : Eu, Ca ₂ Si ₅ N ₈ : Eu, SrAlSi ₄ N ₇ : Eu, and (Sr, Ba) SiN ₂ : Eu.

Here, the fourth fluorescent material may have an amount of 3.6 to 11.3 wt% based on 100 wt% of the sum of the first to fourth phosphors.

Here, the mixture of at least one of the first and second phosphors, and the third and fourth phosphors may have a CRI index of 82 to 97. [

According to a second aspect of the present invention, there is provided a light emitting device comprising: a light emitting element; A first phosphor that is excited by light emitted from the light emitting device and emits light having a center wavelength in a range of more than 520 nm to 550 nm; A second phosphor which is excited by light emitted from the light emitting device and emits light having a center wavelength in a range of 560 to 600 nm; A third phosphor that is excited by light emitted from the light emitting device and emits light having a center wavelength in a range of 500 to 520 nm; And a fourth phosphor that is excited by the light emitted from the light emitting device and emits light whose center wavelength is located in the 620 to 660 nm band.

Here, the weight ratio of the first phosphor, the second phosphor, the third phosphor and the fourth phosphor is 21.4 wt% based on the sum of the first phosphor, the second phosphor, the third phosphor and the fourth phosphor, %, 50.6 wt%, 16.7 wt% and 11.3 wt%, respectively.

Here, the fourth phosphor may be excited by the light emitted from the light emitting device, and the center wavelength may be located in the 640 to 660 nm band.

The present invention has the following effects.

Firstly, the present invention can provide a light emitting device including a yellow light emitting phosphor having excellent light emission characteristics, and this yellow light emitting phosphor can minimize light flux (luminance) degradation and improve color rendering index (CRI).

The color rendering index can be improved by the continuous spectrum design of the present invention, and by providing an optimal mixing ratio of the phosphors, the color of the light color region can be expressed in the display through the implementation of the light emitting device having a wide spectrum .

Fig. 1 is a graph showing the visual acuity of a person.
2 is a graph showing the emission spectrum of a conventional light emitting device.
3 is a graph showing an emission spectrum of an example of the light emitting device.
4 is a graph showing a luminescence spectrum according to another example of the light emitting device.
5 is a graph showing an example of an excitation spectrum according to a red emission wavelength.
6 is a cross-sectional view showing an example of a light emitting device package using the yellow light emitting phosphor of the present invention.
7 is a cross-sectional view showing another example of a light emitting device package using the yellow light emitting phosphor of the present invention.
FIG. 8 is a partial enlarged view of FIG. 6 for explaining the process of realizing white light using the yellow light-emitting fluorescent material of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. Rather, the intention is not to limit the invention to the particular forms disclosed, but rather, the invention includes all modifications, equivalents and substitutions that are consistent with the spirit of the invention as defined by the claims.

It will be appreciated that when an element such as a layer, region or substrate is referred to as being present on another element "on," it may be directly on the other element or there may be an intermediate element in between .

Although the terms first, second, etc. may be used to describe various elements, components, regions, layers and / or regions, such elements, components, regions, layers and / And should not be limited by these terms.

According to the present invention, at least one of green and amber (hereinafter referred to as amber) phosphors, which are excellent in excitation efficiency by near ultraviolet and blue excitation sources, and short wavelength green and red phosphors are further included on the blue light emitting element It is possible to realize yellow light having excellent brightness and high color rendering property.

These phosphors constitute a yellow light-emitting phosphor. The first phosphor (green phosphor) emits light whose center wavelength is in a range of more than 520 nm and 550 nm, excited by the blue light-emitting device, and has a center wavelength in the range of 560 to 600 nm (Amber phosphor) that emits light having a center wavelength in a range of 500 to 520 nm and a third phosphor (short wavelength green phosphor) that emits light having a center wavelength in a range of 500 to 520 nm and a second phosphor And a fourth phosphor that emits light positioned in a band of the second phosphor.

Hereinafter, the first phosphor is referred to as a green phosphor, the second phosphor as an amber phosphor, the third phosphor as a short-wavelength green phosphor, and the fourth phosphor as a red phosphor.

The green phosphor, the amber phosphor, the short wavelength green phosphor, and the red phosphor may include the following materials.

In other words, the green phosphor is composed of BaSi ₄ N ₇ : Eu, Ba ₃ Si ₆ O ₁₂ N ₂ : Eu, CaSi ₂ O ₂ N ₂ : Eu, SrYSi ₄ N ₇ : Eu, And at least one of SiAlON (Ca-α-SiAlON: Yb), LuAG (Lu ₃ Al ₅ O ₁₂ : Ce) and SrSi ₂ O ₂ N ₂ : Eu.

Such a green phosphor can emit light having a central wavelength in the above-mentioned 520 to 550 nm band.

The amber phosphors include? -Type SiAlON (Li-? -SiAlON: Eu) having Li as a metal component,? -Type SiAlON (Ca-? -SiAlON: Eu) having Ca as a metal component and Ba ₂ Si ₅ N ₈ : Eu Or the like.

Such an amber phosphor can emit light having a center wavelength in the range of 560 to 600 nm.

The short-wavelength green phosphor may include at least one of BaSi ₂ O ₂ N ₂ , BaAl ₂ O _4, and SrAl ₂ O ₄ . Such a short-wavelength green phosphor can emit light having a center wavelength in a range of 500 to 520 nm.

The red phosphor may be at least one selected from the group consisting of CaAlSiN ₃ : Eu, (Sr, Ca) AlSiN ₃ : Eu (SCASN), Sr ₂ Si ₅ N ₈ : Eu, K ₂ SiF ₆ : Mn, La ₃ Si ₆ N ₁₁ : Ce, SrAlSiN ₃ : Eu, SrCN ₂ : Eu, Ca ₂ Si ₅ N ₈ : Eu, SrAlSi ₄ N ₇ : Eu and (Sr, Ba) SiN ₂ : Eu.

Such a red phosphor can emit light having a center wavelength in a range of 620 to 660 nm.

Although the green phosphor, the amber phosphor, the short wavelength green phosphor and the red phosphor are mainly the nitride phosphor or the oxynitride phosphor, other phosphor may be used.

Here, the amber phosphor is represented by the following chemical formula 1, x is 0.01? X? 0.1, m and n are at least one of 0? M? 2 and 0? N? 1.

≪ Formula 1 >

On the other hand, the red phosphor may have a light absorptance of 50% or less at a wavelength of 550 nm. That is, the ratio of excitation by light having a wavelength of 550 nm may be 50% or less. This will be described in detail later.

Based on the green phosphor and the amber phosphor having such characteristics, the yellow light-emitting phosphor realized by mixing the phosphor including at least one of the short-wavelength green fluorescent material and the red fluorescent material has an emission spectrum in the wavelength band of 480 nm to 780 nm May be at least 120 nm. This may mean that the color rendering property of light is greatly increased.

Here, the green phosphor may have a content of 50.6 to 67.7 wt% when the sum of these green phosphor, amber phosphor, short wavelength green phosphor and red phosphor is 100 wt% (weight ratio).

Here, the amber phosphor may have an amount of 16.7 to 28.7 wt%, assuming that the sum of these green phosphor, amber phosphor, short wavelength green phosphor and red phosphor is 100 wt%.

Here, the short-wavelength green phosphor may have a content of 21.4 to 27.5 wt%, assuming that the sum of these green phosphor, amber phosphor, short-wavelength green phosphor and red phosphor is 100 wt%.

Here, the red phosphor may have an amount of 3.6 to 11.3 wt%, assuming that the sum of the green phosphor, amber phosphor, short wavelength green phosphor and red phosphor is 100 wt%.

In addition to such green phosphors and amber phosphors, a mixture realized by mixing phosphors further including at least one of a short-wavelength green fluorescent material and a red fluorescent material is excited by near-ultraviolet light or blue light to emit yellow light of high luminance It can emit light. Further, such yellow light is mixed with blue light, which is excitation light, to emit white light having high luminance and high color rendering property. The excitation ratio is excellent in such near ultraviolet light or blue light, and high-efficiency phosphor characteristics can be exhibited.

The? -Type SiAlON having Ca as a metal component has a luminescent center wavelength of about 600 nm. However, when Li -? - SiAlON having a central wavelength of 550 to 590 nm is used as described above, The characteristic can be increased by 25%. More preferably, allowing the light having the center wavelength in the 578 to 588 nm band to emit light can further improve the luminosity characteristic. Further, it is possible to further improve the color rendering property by increasing the luminance by mixing the red phosphor whose absorption is controlled in the 550 to 560 nm band. However, as mentioned above, in some cases, the characteristics of the present invention can also be achieved in the case of a phosphor emitting light whose central wavelength lies in the 560 to 600 nm band.

1 is a photonic curve showing a person's visual sense characteristic.

As shown, the value of human visibility has a maximum at a wavelength of approximately 555 nm. That is, for light of the same intensity, one perceives light in the 555 nm wavelength band as the strongest.

Therefore, Li-α-SiAlON having a central wavelength of 550 to 590 nm, which is used in the present invention, is superior to the? -Type SiAlON having a luminescence center wavelength of about 600 nm, which is superior to the visual sensitivity.

That is, since the light of the same intensity can be detected more brighter, the adjustment of the emission wavelength can act as an effect of increasing the luminance.

The Li-α-SiAlON which can be used as the amber phosphor of the present invention can improve the luminous characteristic by about 25% as compared with Ca-α-SiAlON for the emission of the same peak intensity.

In the present invention, in order to realize light emission having a center wavelength of 550 to 590 nm, it is possible to control the substitution amount of Li and the amount of oxygen during SiAlON synthesis.

Table 1 shows the emission wavelength (peak wavelength) and the emission luminance of the phosphor obtained by adjusting the oxygen content (n: the value in Chemical Formula 1) in the implementation of such an amber phosphor.

For such luminescence, m and n in formula (1) may satisfy at least one of 0? M? 2 and 0? N? 1. In the general formula (1), x represents the content of the activator (Eu), and it is usually substituted within 10% with metal ions (lithium (Li) and aluminum (Al)). That is, x may have a value between 0.01 and 0.1.

As shown in Table 1, it can be seen that the emission wavelength can be changed depending on the content of oxygen (Oxygen) in the amber phosphor. That is, when the content (n) of oxygen is 0, the emission wavelength is 588 nm and the emission luminance at this time is 95%. When the content (n) of oxygen is 1, Lt; RTI ID = 0.0 > 578 nm. ≪ / RTI >

When the content (n) of oxygen is changed to 1? N? 2 in order to improve the luminous efficiency through the additional luminosity characteristic, it is possible to change the emission wavelength to 560 nm. Thus, by adjusting the oxygen content, it is particularly easy to move the emission wavelength to a short wavelength by increasing the oxygen content.

Table 1 shows that the emission luminance is highest when the content (n) of oxygen (oxygen) is 0.1 and the emission wavelength is 583 nm.

As described above, in the present invention, the first phosphor as the green light emitting phosphor and the second phosphor as the amber color light emitting phosphor are mixed to realize yellow light having excellent brightness.

Further, by adjusting the emission wavelength and mixing ratio of each of the green phosphor and the amber phosphor, the emission luminance can be improved. In addition, the color rendering index (CRI) indicating the color rendering property of the light source can be improved together.

For this purpose, characteristics can be controlled between the luminance of the phosphor and the color rendering index. For example, if the emission wavelength is 583 nm, a phosphor having an emission wavelength of 580 nm can be used to improve the color rendering index even if the emission luminance is high.

The color rendering index (CRI) is an index for indicating the color rendering property of a light source, and is a numerical value indicating the degree to which the color perception of the object under the sample light source matches the color perception of the same object under the reference light prescribed.

Table 2 shows that the luminance and the CRI can be improved by mixing the green phosphor and the amber phosphor in this manner.

That is, in contrast to the implementation of a yellow light-emitting phosphor using a conventional yellow phosphor (yellow phosphor, commonly used YAG (Yttrium Aluminum Garnet) phosphor) and Ca-? -SiAlON, Green) phosphor (having a peak wavelength of 535 nm) and an Amber phosphor (having a peak wavelength of 583 nm), the light emission luminance and CRI can be improved as compared with the conventional yellow phosphor.

As described above, since the conventional light emitting device or illumination device using LEDs emits white light by a combination of blue light and yellow phosphor, it is difficult to obtain a high color rendering light (natural light or incandescent light) because of lack of green and red light elements There is a disadvantage in that the color recognized by a person and the color felt by a person in a low color rendering LED illumination are different.

As shown in FIG. 2, in the conventional LED light emitting device, the spectrum region A between 480 and 530 nm and the color information in the region B between 630 nm and 730 nm are different from each other It is possible to express distorted colors such as light transmitted through the cellophane.

3 is a graph showing an emission spectrum of an example of the light emitting device.

3, when a light emitting device is implemented using a green phosphor emitting light of a wavelength of 520 to 550 nm band and an amber phosphor emitting light of a wavelength of 560 to 600 nm on a blue LED, Respectively.

As shown in the figure, it can be seen that the color spectrum in the spectral region C between 480 nm and 530 nm and the region D between 630 nm and 730 nm are improved as compared with the case of FIG.

4 is a graph showing a spectrum showing another example of the light emitting device.

The light emitting device shown in Fig. 4 includes a green phosphor emitting light of a wavelength in the range of 520 to 550 nm and an amber phosphor emitting light of a wavelength in the range of 560 to 600 nm. The light emitting device includes at least one of a short wavelength green fluorescent material and a red fluorescent material Is used as the phosphor. As an example, FIG. 4 shows a spectrum when both the green phosphor and the amber phosphor include both the short-wavelength green phosphor and the red phosphor.

As shown in FIG. 4, it can be seen that the blue excitation light and the yellow light emitted by the excitation of the yellow light-emitting phosphor by the blue light are mixed with each other to emit white light of excellent quality.

That is, the yellow phosphor including the green phosphor and the amber phosphor, and further including at least one of the short-wavelength green phosphor and the red phosphor, is mixed with the green phosphor and the amber phosphor, It can be seen that the color information is rich in the spectral region C between 530 nm and 530 nm and in the region D between 630 nm and 730 nm.

As described above, a light emitting device package that emits yellow light by a combination of a green phosphor and an amber phosphor has a strong peak intensity around a wavelength of 555 nm, which is excellent in luminous efficiency.

However, the half width of the wavelength in the 500 to 600 nm band may not be sufficiently wide in view of high quality illumination.

Therefore, by improving the spectrum of the spectral range between 480 and 530 nm (C) and the range between 630 nm and 730 nm (D) in order to realize high-quality color representation in illumination, The color rendering property can be improved to a level close to the sunlight.

Further, through the implementation of the light emitting device package having such a wide spectrum, the color of the light gamut can be expressed in the display using the light emitting device package.

As mentioned above, such a color rendering index (CRI) is an index for indicating the color rendering property of a light source, which is the degree to which the color perception of the object under the sample light source coincides with the color perception of the same object under the prescribed reference light .

The color rendering index in the illumination is a numerical value indicating how much the visual environment recognizing the color is similar to the environment under the sunlight. Specifically, the degree of matching of the reflection color of the object with the reference color in the test light source It is expressed numerically to indicate the quality of illumination.

As described above, the yellow phosphor including the green phosphor and the amber phosphor, and further including at least one of the short-wavelength green phosphor and the red phosphor, can be obtained by mixing the green phosphor and the amber phosphor described above The color rendering property can be improved. At this time, the color rendering property can be improved without lowering the light efficiency.

That is, in order to improve the spectrum in such a form, a phosphor of a short wavelength green phosphor or a red phosphor of a long wavelength may be added to the green phosphor and the amber phosphor, or both of the green phosphor of short wavelength and the red phosphor of long wavelength may be mixed. Through this, the color rendering property can be greatly improved, and even peak intensity can be realized.

On the other hand, as shown in Fig. 5, the red phosphors can emit light (excitation) by emitting green phosphors and amber phosphors, as well as yellow luminescence, which is a mixed light of these luminescence, in addition to blue excitation light.

Such a red phosphor may use a phosphor having a wavelength band of 630 nm or a phosphor having a wavelength band of 650 nm.

5, the dotted line on the left shows the excitation spectrum, that is, the spectrum of the light absorbed by the red phosphor, and the solid line on the right shows the emission spectrum.

Therefore, by adjusting the excitation spectrum of such a red phosphor, absorption of light other than blue excitation light by the red phosphor can be minimized. Accordingly, the luminous efficiency of the yellow phosphor can be prevented from decreasing. As a result, the luminous efficiency can be increased while improving the color rendering.

For this purpose, the absorption intensity at a wavelength of 550 nm of the red phosphor can be adjusted to be 50% or less. That is, the absorption at 50% of the absorption spectrum intensity of the red phosphor can be adjusted to the wavelength of 550 nm or less to minimize the absorption of the luminescence of the green, amber and yellow phosphors.

The design of such a red phosphor is described in detail as follows.

As described above, when the red phosphor is mixed for improving the light emitting property such as improving the color rendering property, as shown in Fig. 5, the emission wavelength band (for example, green 530 nm and 560 nm in a yellow color) is absorbed, and thus the luminance of the light can be lowered.

In order to minimize such a phenomenon, the excitation spectrum of the red phosphor is shifted to a short wavelength so that the amount of absorption of light at a wavelength of 550 nm or less is 50%, thereby minimizing the absorption of light other than the excitation light.

FIG. 5 shows an example of excitation spectrum according to each red emission wavelength.

In this example, it can be seen that the red phosphor having a peak wavelength of 610 nm has an absorption rate of 50% or less at a wavelength of 550 nm. Exactly, it can be seen that the absorption rate is 50% at a wavelength of 547 nm. In addition, the red phosphor having a peak wavelength of 630 nm has an absorption rate of 50% at a wavelength of 564 nm, a red phosphor having a peak wavelength of 650 nm has an absorption rate of 50% at a wavelength of 585 nm and a red phosphor having a peak wavelength of 660 nm Shows that the absorption ratio becomes 50% at a wavelength of 600 nm.

Through this design, it can be seen that the absorption by light other than the excitation light can be minimized by using a red phosphor having a peak wavelength of 610 nm with a water absorption of 50% or less at a wavelength of 550 nm. However, in some cases, red phosphors having peak wavelengths of 630 nm, 650 nm and 660 nm may be used in the above examples.

As described above, it is possible to control the absorptivity of the red phosphor and to select the phosphor according to the peak wavelength of the adjusted red phosphor, thereby improving the color rendering property and increasing the luminous efficiency at the same time.

<Examples>

Table 3 shows the CRI according to the phosphor content ratio used in the light emitting device of the present invention.

In Table 3, a short wavelength green phosphor having a peak wavelength of 500 nm, a green phosphor having a peak wavelength of 530 nm, an amber phosphor having a peak wavelength of 580 nm and an emission wavelength of 600 nm, and a red phosphor having a peak wavelength of 630 nm and 650 nm Yellow phosphors are realized, and CRI according to the contents of these phosphors is shown.

As described above, a short wavelength green phosphor, a green phosphor having a peak wavelength of 530 nm, an amber phosphor having a peak wavelength of 580 nm and an emission wavelength of 600 nm, and a red phosphor having a peak wavelength of 630 nm and 650 nm, Can be implemented.

As an example, in addition to LuAG as a green phosphor, Li-α-SiAlON as an amber phosphor, BaSi ₂ O ₂ N ₂ as a short wavelength green phosphor and SCASN ((Sr, Ca) AlSiN ₃ : Eu having a peak wavelength of 630 nm as a red phosphor) And a long wavelength red phosphor having a peak wavelength of 650 nm are used in combination.

When these materials are used, it can be seen that the result of CRI 80 or more can be obtained in Condition 6, Condition 8, Condition 9, and Condition 10.

That is, in Condition 6, the green phosphor, the amber phosphor having a peak wavelength of 580 nm, and the red phosphor having a long wavelength of 650 nm are used, and a CRI index of 82 can be obtained with high color rendering. In Condition 8, the green phosphor, A high color rendering emission having a CRI index of 83 can be obtained by using a red phosphor having a wavelength of 630 nm.

Further, in Condition 9, a high color rendering emission of a CRI index 86 can be obtained by using a short wavelength green phosphor, a green phosphor and an amber phosphor having a peak wavelength of 580 nm. In Condition 10, a short wavelength green phosphor, a green phosphor, A high color rendering emission of CRI index 97 can be obtained by using a phosphor and a red phosphor having a peak wavelength of 650 nm.

The weight ratios of the short wavelength green phosphor, the green phosphor, the amber phosphor and the red phosphor at this time are shown in Table 3, respectively. The ratios in Table 3 represent weight ratios.

As a comparative example, it can be seen that the CRI indices of the phosphors of each combination shown in Condition 1 to Condition 5 and Condition 7 are 50 to 70, which is lower than that of the present invention.

Thus, it can be seen that the light intensity and visibility are not reduced as compared with the comparative example, and high-quality white light can be produced together with the near ultraviolet or blue light emitting device.

In the case of this comparative example, as shown in Fig. 3, it shows improved characteristics compared to a conventional yellow phosphor such as YAG.

As shown in the figure, the spectrum of the yellow light-emitting phosphor of the present invention shows that a relatively uniform peak intensity is distributed in the visible light wavelength range (380 nm to 780 nm), and thus, And the color rendering property is improved.

Thus, it can be seen that the light emission is enhanced in the spectrum region C between 480 nm and 530 nm and the region D between 630 nm and 730 nm, which are excited by near ultraviolet or blue light.

As described above, according to the present invention, it is possible to provide a yellow light-emitting phosphor having excellent light emission characteristics, and it is understood that such a yellow light-emitting phosphor minimizes light flux (luminance) deterioration and improves the color rendering index (CRI) .

Also, it can be used in designing a phosphor having a CRI 80 or higher color rendering property in this manner, and it is believed that the CRI can be improved to a level close to that of the sunlight.

The continuous spectrum design according to the present invention can improve the color rendering index and provide an optimum mixing ratio of the phosphors to realize a light emitting device (for example, a light emitting device package) having a broad spectrum, Can be expressed.

&Lt; Light emitting device package &

6 is a cross-sectional view showing an example of a light emitting device package using the yellow light emitting phosphor of the present invention. FIG. 6 shows an example of a lamp-type light emitting device package 100 according to an embodiment of the present invention. Such a light emitting device package may be a light emitting device.

The lamp-type white light emitting device package 100 includes a pair of lead frames 110 and 120 and a light emitting device 130 that generates light according to application of a voltage.

The light emitting device 130 is electrically connected to the lead frames 110 and 120 by a wire 140 and the light transmitting resin 150 is molded on the light emitting device 130. The light emitting device 130 may emit near ultraviolet light or blue light.

Further, a laser diode, a surface-emission laser diode, an inorganic electroluminescent element, an organic electroluminescent element, or the like may be used as a light emitting element having a main emission peak in the same wavelength region instead of the near ultraviolet light emitting element. In the present invention, as a preferred application example, a nitride semiconductor light emitting diode is used. In FIG. 6, the light emitting device 130 is schematically represented, and both the horizontal and vertical nitride semiconductor light emitting diodes can be used.

The light-transmitting resin 150 may be provided with phosphors 170, 171, 172, and 173 dispersed therein. The light-transmitting resin 150 may include a covering material 160 .

Each of the phosphors 170, 171, 172 and 173 used here includes a first phosphor (green phosphor 170), a second phosphor (amber phosphor) 171, a third phosphor (short wavelength green phosphor) and a fourth phosphor And red phosphors 173) to emit yellow light.

8, all of the first to fourth phosphors are shown. However, as described above, only one of the third phosphor (short wavelength green phosphor) and the fourth phosphor (red phosphor) 173 is used It is possible.

Here, other phosphors may be mixed and used as the case may be. Two or more kinds of such phosphors may be provided in some cases.

As the light transmitting resin 150 used as a molding member, a light transmitting epoxy resin, a silicone resin, a polyimide resin, a urea resin, an acrylic resin, or the like may be used. Preferably, a light-transmitting epoxy resin or a light-transmitting silicone resin can be used.

The light transmitting resin 150 of this embodiment may be entirely molded around the light emitting device 130, but may be partially molded at a light emitting portion as necessary.

That is, in the case of a high output light emitting device, uniform molding of the light emitting device 130 may result in uniform dispersion of the phosphors 170, 171, 172, and 173 dispersed in the light transmitting resin 150 to be. In this case, it may be advantageous to partially mold the light emitting portion.

7 is a cross-sectional view showing another example of a light emitting device package using the yellow light emitting phosphor of the present invention. 7 shows a surface-mounted light-emitting device package 200. Fig.

8, the surface mount type light emitting device package 200 according to an exemplary embodiment of the present invention includes lead frames 210 and 220 of positive and negative electrodes, and lead frame 210 And 220, and generates light according to application of a voltage. The light emitting device 240 may use a light emitting diode or a laser diode.

Although FIG. 7 shows an example of the light emitting device 240 having a horizontal structure, it is needless to say that a vertical light emitting device can be used.

The light emitting device 240 is electrically connected to the lead frames 210 and 220 by a wire 250 and the light transmitting resin 260 is molded on the light emitting device 240. The lead frames 210 and 220 may be fixed by the package body 230, and the package body 230 may provide a reflective cup shape.

Further, the light transmitting resin 260 may be formed by dispersing the phosphors 270, 271, 272, and 273.

The phosphors 270, 271, 272, and 273 used in the first and second phosphors 270 and 271 may be formed of a mixture of at least one of the third phosphor 272 and the fourth phosphor 273, They may be mixed and dispersed. In addition, other phosphors may be dispersed together. Two or more kinds of such phosphors may be provided in some cases.

As the light transmitting resin 260 used as a molding member, a light transmitting epoxy resin, a silicone resin, a polyimide resin, a urea resin, an acrylic resin, or the like can be used. Preferably, a light-transmitting epoxy resin or a light-transmitting silicone resin can be used.

The light transmitting resin 260 may be entirely molded around the light emitting device 240, but may be partially molded at the light emitting portion as necessary.

The same elements as those described with reference to Fig. 6 can be applied to the parts not described in the other parts.

The light emitting device package 100, 200 according to the present invention described above in detail can be implemented as a white light emitting package.

FIG. 8 is a partial enlarged view of FIG. 6, and a process of implementing white light will be described as follows. This description can be applied as it is in the case shown in Fig.

Blue light having a wavelength range of 400 to 480 nm corresponding to the near ultraviolet light or blue light emitted from the light emitting device 130 passes through the phosphors 170, 171, 172, and 173.

Here, some light excites the phosphors 170, 171, 172, and 173 to generate light having a main peak in the wavelength range of 500 to 600 nm as shown in FIG. 6, and the remaining light is blue light As it is.

At this time, the light emitted from the light emitting element 130 excites the respective phosphors 170, 171, 172, and 173 to emit light a, b, c, and d from these phosphors, And the yellow light may be mixed with the blue light of the light emitting device 130 to emit white light.

As a result, white light having a spectrum of a wide wavelength of 400 to 700 nm is emitted. At this time, a broad spectrum is formed by at least one of the short-wavelength green phosphor 172 and the red phosphor 173, thereby realizing high-quality light with excellent color rendering properties.

It should be noted that the embodiments of the present invention disclosed in the present specification and drawings are only illustrative of specific examples for the purpose of understanding and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other modifications based on the technical idea of the present invention are possible in addition to the embodiments disclosed herein.

100, 200: light emitting device package 110, 120, 210, 220: lead frame
130, 240: light emitting device 140, 250: wire
150, 260: light transmitting resin 160: exterior material
170, 171, 172, 173, 270, 271, 272, 273:
230: package body

Claims (14)

A light emitting element;
A first phosphor that is excited by light emitted from the light emitting device and emits light having a center wavelength in a range of more than 520 nm to 550 nm; And
And a second phosphor which is excited by the light emitted from the light emitting device and emits light having a center wavelength in a range of 560 to 600 nm,
A third phosphor that is excited by the light emitted from the light emitting device and emits light having a center wavelength in a range of 500 to 520 nm and a third phosphor that is excited by the light emitted from the light emitting device and has a center wavelength of 620 to 660 nm And a fourth phosphor that emits light located in the second phosphor layer. The phosphor according to claim 1, wherein the first phosphor is BaSi ₄ N ₇ : Eu, Ba ₃ Si ₆ O ₁₂ N ₂ : Eu, CaSi ₂ O ₂ N ₂ : Eu, SrYSi ₄ N ₇ : And at least one of? -Type SiAlON (Ca-α-SiAlON: Yb), LuAG (Lu ₃ Al ₅ O ₁₂ : Ce) and SrSi ₂ O ₂ N ₂ : Eu. The light emitting device according to claim 1, wherein the first phosphor has a content of 50.6 to 67.7 wt% based on 100 wt% of the sum of the first to fourth phosphors. The phosphor according to claim 1, wherein the second phosphor is at least one selected from the group consisting of? -Type SiAlON (Li-α-SiAlON: Eu) having Li as a metal component,? -Type SiAlON (Ca- Ba ₂ Si ₅ N ₈ : Eu, and / or Ba ₂ Si ₅ N ₈ : Eu. The phosphor according to claim 1, wherein the second phosphor is expressed by the following formula (1)
&Lt; Formula 1 >

x is 0.01? x? 0.1, and m and n satisfy at least one of 0? m? 2 and 0? n? 1. The light emitting device according to claim 1, wherein the second phosphor has a content of 16.7 to 28.7 wt% based on 100 wt% of the sum of the first to fourth phosphors. The method of claim 1, wherein said third _{phosphor, BaSi 2 O 2 N 2,} BaAl 2 O 4 and SrAl light emitting device characterized in that it comprises at least one of the ₂ O _4. The light emitting device according to claim 1, wherein the third fluorescent material has a content of 21.4 to 27.5 wt% based on 100 wt% of the sum of the first to fourth phosphors. The phosphor according to claim 1, wherein the fourth phosphor is at least one selected from the group consisting of CaAlSiN ₃ : Eu, (Sr, Ca) AlSiN ₃ : Eu, Sr ₂ Si ₅ N ₈ : Eu, K ₂ SiF ₆ : Mn, La ₃ Si ₆ N ₁₁ : _{Ce, SrAlSiN 3: Eu, SrCN} 2: Eu, Ca 2 Si 5 N 8: Eu, SrAlSi 4 N 7: Eu and (Sr, Ba) SiN _2: light-emitting device characterized in that it comprises at least one of Eu . The light emitting device according to claim 1, wherein the fourth fluorescent material has a content of 3.6 to 11.3 wt% based on 100 wt% of the sum of the first to fourth phosphors. The light emitting device according to claim 1, wherein a mixture of the first phosphor and the second phosphor, and a mixture of at least one of the third and fourth phosphors has a CRI index of 82 to 97. A light emitting element;
A first phosphor that is excited by light emitted from the light emitting device and emits light having a center wavelength in a range of more than 520 nm to 550 nm;
A second phosphor which is excited by light emitted from the light emitting device and emits light having a center wavelength in a range of 560 to 600 nm;
A third phosphor that is excited by light emitted from the light emitting device and emits light having a center wavelength in a range of 500 to 520 nm; And
And a fourth phosphor which is excited by the light emitted from the light emitting device and emits light having a center wavelength in a range of 620 to 660 nm. 13. The method according to claim 12, wherein the weight ratio of the first phosphor, the second phosphor, the third fluorescent material, and the fourth fluorescent material is 100 wt% in total of the first fluorescent material, the second fluorescent material, the third fluorescent material and the fourth fluorescent material , 21.4 wt%, 50.6 wt%, 16.7 wt%, and 11.3 wt%, respectively. 13. The light emitting device according to claim 12, wherein the fourth phosphor is excited by light emitted from the light emitting device and has a center wavelength in a range of 640 to 660 nm.

Images