JP2007180377A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device which is good in both emission efficiency and color rendering property. <P>SOLUTION: The light emitting device includes a light emitting element which emits light of which the peak wavelength is more than 440 nm and less than 480 nm; and three or more phosphors which emit light of a peak wavelength different to the light emitting device by irradiating light from the light emitting device, and emit the light of color mixture with luminescent color from the light emitting devices and luminescent color from the phosphor. Here, as the light emitting device, it is preferable to use a light emitting diode or a semiconductor laser including at least nitride semiconductor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light-emitting device, and more particularly to a light-emitting device that has both good luminous efficiency and color rendering.

  Traditionally, the lighting field has been mainly tube-based. However, in recent years, due to the remarkable improvement in the optical characteristics of light-emitting diodes or semiconductor lasers that emit light in the ultraviolet to blue wavelength range, this is used as an excitation light source and emits white light that combines this excitation light source and phosphor. Light emitting devices have been commercialized and are being used in the lighting field.

  There are roughly two types of configurations of a light-emitting device that combines a light-emitting element that emits light having a wavelength in the blue region as an excitation light source and a phosphor.

  The first is a combination of a light emitting element that emits blue light with a wavelength of 460 nm and a YAG: Ce phosphor that emits yellow light with a wavelength of 560 nm when irradiated with the blue light, and emits blue light from the light emitting element. In this configuration, white light is obtained by mixing color with yellow light from the phosphor (see, for example, Patent Document 1).

The second is a combination of a light emitting element that emits blue light having a wavelength of 460 nm and a phosphor that emits red light and green light when irradiated with the blue light, and the blue light and the phosphor of the light emitting element are combined. In this configuration, white light is obtained by mixing red light and green light (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 10-242513 Japanese Patent Laid-Open No. 2002-203989

  As a result of detailed studies by the present inventor, a light emitting device having a first configuration in which a light emitting element that emits blue light and a phosphor that emits yellow light (yellow phosphor) is combined is light emitting of the phosphor. It was found that the theoretical limit efficiency showing the characteristics was as high as about 240 (lm / W).

  Here, a theoretical limit efficiency of 240 (lm / W) means that when the phosphor is irradiated with light having an intensity of 1 W, the internal quantum efficiency of the phosphor (the number of photons of light emitted from the phosphor / phosphor) Light of 240 (lm) when the phosphor is absorbed by the phosphor in a state in which the ratio of the number of photons of light irradiated to the phosphor is 100% and all of the light irradiated to the phosphor is absorbed. That you can get.

The luminous efficiency (lm / W) in the light emitting device is obtained by multiplying the power conversion efficiency of the light emitting element and the theoretical limit efficiency of the phosphor by the internal quantum efficiency and the absorption rate. That is, it is represented by the following formula (1).
Luminous efficiency (lm / W) = Theoretical limit efficiency of phosphor (lm / W) × Power conversion efficiency of light emitting element × Internal quantum efficiency × Absorptance (1)
For this reason, in order to improve the luminous efficiency of the light emitting device, it is preferable that the theoretical limit efficiency of the phosphor is as high as possible.

  On the other hand, the color of an object viewed under sunlight (standard light D65) and the light emitted from the light-emitting device, which are one of the indices when the light-emitting device having the first configuration is used for lighting purposes The so-called average color rendering index (Ra), which indicates the difference in color appearance from the object viewed under, was about 80. Further, regarding the special color rendering evaluation numbers R1 to R8, R4 and R8 were about 60, which was relatively low. Here, the average color rendering index is defined as an average value from special color rendering indices R1 to R8. Although the value of the average color rendering index (Ra) 80 is high to some extent, because of the color bias in the spectrum, R4 (yellowish green) and R8 (purple) of the test colors cannot be sufficiently reproduced, and the average color rendering evaluation The number (Ra) cannot be high enough.

  Further, the value of R9 in the special color rendering index indicating the appearance of the red object is very low, and there is a problem that it is difficult to reproduce the red object neatly by this light emitting device.

  Therefore, the theoretical limit efficiency of the phosphor of the light emitting device having the first configuration is sufficiently high, and the light emission efficiency of the light emitting device can be high, but the color rendering property cannot be sufficiently high due to the deviation of color components. was there.

  Therefore, a light emitting device having a second configuration in which a light emitting element that emits blue light and a phosphor that emits red light and green light, respectively, is combined has been proposed. Since the light emitting device having the second configuration includes all three primary colors of light, the average color rendering index (Ra) can be very good at about 85 by selecting the peak wavelength and spectrum. Also, the value of the special color rendering index (R9) can be about 50. As a result, various color objects, particularly red objects, can be reproduced beautifully. However, since the phosphor containing red light (red phosphor) is included, the Stokes loss increases, the theoretical limit efficiency is only about 190 (lm / W), and the light emission efficiency of the light emitting device is poor. .

  Therefore, in any of the above-described configurations, it is a fact that a light-emitting device having both excellent luminous efficiency and color rendering properties cannot be obtained.

  An object of the present invention is to provide a light emitting device that has both excellent luminous efficiency and color rendering.

  The present invention includes a light emitting element that emits light having a peak wavelength of 440 nm or more and less than 480 nm, and three or more phosphors that emit light having a peak wavelength different from that of the light emitting element by irradiating light from the light emitting element. , And a light emitting device that emits light of a mixed color of the color emitted from the light emitting element and the color emitted from the phosphor.

  Here, in the light emitting device of the present invention, it is preferable to use a light emitting diode or a semiconductor laser including at least a nitride semiconductor as the light emitting element.

  In the light emitting device of the present invention, it is preferable that all of the peak wavelengths of light emitted from the phosphor are in the range of 490 nm or more and less than 760 nm.

  In the light emitting device of the present invention, it is preferable that the peak wavelengths of light emitted from the phosphor are arranged at substantially equal intervals.

  In the light-emitting device of the present invention, at least one of the peak wavelengths of light emitted from the phosphor is in the range of 490 nm to less than 560 nm, at least one is in the range of 560 nm to less than 610 nm, and at least one is It is preferably in the range of 610 nm or more and less than 650 nm.

  In the light-emitting device of the present invention, it is preferable to use a phosphor that includes a mixed crystal of a semiconductor and that can control the peak wavelength of light emitted from the phosphor by the mixed crystal ratio of the semiconductor.

  In the light emitting device of the present invention, it is preferable to use a phosphor containing semiconductor nanoparticles and capable of controlling the peak wavelength of light emitted from the phosphor by the particle diameter of the nanoparticles.

  In addition, the light emitting device of the present invention includes a lead frame in which a light emitting element is installed, a wire that electrically connects a power supply unit provided in the lead frame and the light emitting element, and a light transmitting property in which a phosphor is dispersed. And a resin. Here, the light emitting element is preferably installed in a light transmissive resin.

  The light-emitting device of the present invention includes a light guide for propagating light emitted from the light-emitting element, and a light-transmitting resin in which a phosphor is dispersed at one end of the light guide. It can be set as the structure by which the light which propagated is irradiated to a fluorescent substance from the end of a light guide. Here, an optical fiber can be used as the light guide.

  According to the present invention, it is possible to provide a light emitting device that has both good luminous efficiency and color rendering.

  As a result of the study by the present inventor, the theoretical marginal efficiency is lowered by using light emission from three or more phosphors that emit light having different peak wavelengths from light emission from the light emitting element, that is, four or more kinds of light emission. However, it was found that the average color rendering index (Ra) can be improved in a rather improved state. In order to improve the average color rendering index (Ra), it is desirable that there is no color bias in the spectrum, but it is possible to adjust the shape of the spectrum so that there is no color bias by using four or more types of light emission. This is because it can.

  Further, as a result of the study of the present inventors, the spectrum of the red component can be obtained by using light emission from three or more phosphors that emit light having different peak wavelengths from light emission from the light emitting element, that is, four or more kinds of light emission. It was found that the special color rendering index (R9) indicating the appearance of a red object can be improved.

  As a result of the study by the present inventors, the main factors that determine the theoretical limit efficiency are the wavelength of light emitted from the light emitting element (excitation light wavelength) and the wavelength of light emitted from the phosphor (fluorescence wavelength). It was found that this is due to the thermal energy loss caused by the Stokes loss. Here, the Stokes loss means that when one photon of light emitted from the light emitting element is absorbed by the phosphor and converted into one electron, and this electron is converted into one photon of light emitted from the phosphor, It is energy loss that occurs at a ratio of (1-excitation light wavelength / fluorescence wavelength).

  For example, when the phosphor is irradiated with light having an excitation light wavelength of 460 nm to emit red light having a fluorescence wavelength of 650 nm, approximately 29% of the energy is lost as thermal energy loss.

  Further, in the combination of the light emitting element that emits blue light and the yellow phosphor, the thermal energy loss caused by Stokes loss is about 16% of the total, whereas the light emitting element that emits blue light and the red phosphor. And a phosphor that emits green light (green phosphor), the thermal energy loss caused by Stokes loss is about 21% of the total.

  The combination of a light emitting element that emits blue light, a red phosphor, and a green phosphor contains all three primary colors of light, but the average color rendering index and special color rendering index (R9) are good. The Stokes loss increases as much as the red phosphor is included, and the theoretical limit efficiency decreases.

  In addition, when using a three-color phosphor in which a red phosphor, a green phosphor, and a phosphor emitting blue light (blue phosphor) are used, a red phosphor required to obtain white light Since the intensity of light emitted from the green phosphor and the blue phosphor is uniquely determined, the effect of the Stokes loss cannot be reduced.

  By using fluorescence from three or more phosphors that emit light having different peak wavelengths from the light emission from the light emitting element, that is, by using four or more types of light emission, the shape of the spectrum can be made smooth, and the near ultraviolet region. It has been found that a large Stokes loss that occurs in the case of a discrete three-color phosphor configuration can be reduced with respect to a light emitting element that emits light of a wavelength of, and a light emitting device with high theoretical limit efficiency can be obtained. .

  That is, the light-emitting device of the present invention emits light having a peak wavelength different from that of the light-emitting element by irradiating light from the light-emitting element having a peak wavelength of 440 nm or more and less than 480 nm. And emitting three or more phosphors, and emitting light of a mixed color of the emission color from the light emitting element and the emission color of these phosphors. In the light emitting device of the present invention having such a configuration, the light emission efficiency can be improved, and a plurality of lights having different peak wavelengths are emitted, so that the intensity of each emitted light is appropriately adjusted. As a result, the color rendering properties can be improved. In the present invention, the “peak wavelength” means a wavelength at which the intensity is maximum in each light emitted from the light emitting element and the phosphor.

  Here, as a light emitting element used in the light emitting device of the present invention, it is preferable to use a light emitting diode or a semiconductor laser including at least a nitride semiconductor. This is because, among light-emitting elements that emit light having a peak wavelength of 440 nm or more and less than 480 nm, a light-emitting diode or a semiconductor laser including a nitride semiconductor has very good light emission characteristics.

  In addition, as a light-emitting element used in the light-emitting device of the present invention, a light-emitting element that emits light having a peak wavelength of 440 nm or more and less than 480 nm is used, thereby including blue light, which is one of the three primary colors of light, and color rendering properties. Can be improved.

  Moreover, it is preferable that all the peak wavelengths of the light emitted from the phosphor used in the light emitting device of the present invention are in the range of 490 nm or more and less than 760 nm. In this case, the light emission efficiency of the light emitting device of the present invention tends to be improved, and the color rendering property tends to be improved.

  Moreover, it is preferable that the peak wavelengths of the light emitted from the phosphor used in the light emitting device of the present invention are arranged at substantially equal intervals. Also in this case, the color rendering property tends to be further improved. In addition, “substantially equidistant” means that the standard deviation of the absolute value of the difference between adjacent peak wavelengths among the peak wavelengths of light emitted from the phosphor is 15 nm or less.

  Further, at least one of the peak wavelengths of light emitted from the phosphor used in the light emitting device of the present invention is in the range of 490 nm or more and less than 560 nm, at least one is in the range of 560 nm or more and less than 610 nm, and at least one Is preferably in the range of 610 nm or more and less than 650 nm. By including at least one of the peak wavelengths of light emitted from the phosphor used in the light emitting device of the present invention in the range of 490 nm or more and less than 560 nm, the color rendering property includes green light which is one of the three primary colors of light. Tends to be improved.

  In addition, by setting at least one of the peak wavelengths of light emitted from the phosphor used in the light emitting device of the present invention to a range of 560 nm to less than 610 nm and at least one to a range of 610 nm to less than 650 nm, yellow-red The color rendering property can be improved because light of hue from red to red and red light which is one of the three primary colors of light can be emitted. Moreover, the special color rendering index (R9) indicating the appearance of a red object can be improved by appropriately adjusting the intensity of light having a peak wavelength of these lights.

  Further, as the phosphor used in the light emitting device of the present invention, it is preferable to use a phosphor containing a mixed crystal of a semiconductor and capable of controlling the peak wavelength of light emitted from the phosphor by the mixed crystal ratio of the semiconductor. In this case, it becomes easy to control the peak wavelength of light emitted from the phosphor.

  Further, as the phosphor used in the light emitting device of the present invention, it is preferable to use a phosphor containing semiconductor nanoparticles and capable of controlling the peak wavelength of light emitted from the phosphor by the particle diameter of the nanoparticles. Also in this case, it becomes easy to control the peak wavelength of light emitted from the phosphor. In the present invention, the “nanoparticle” means a particle having a particle diameter of 100 nm or less. In addition, when the phosphor used in the light emitting device of the present invention has a two-layer structure in which the surface of the core made of semiconductor nanoparticles is coated with a clad, the particle size of the core is such that the quantum size effect appears. In addition, the particle diameter of the nanoparticles is preferably 100 nm or less. In addition, the particle diameter of the core in which the quantum size effect (increased light emission efficiency, change in peak wavelength) appears is, for example, about 50 nm or less when the core is made of nanoparticles of II-VI group semiconductor material. In the case of GaN-based nanoparticles, the thickness is about 20 nm or less.

  In addition, the light emitting device of the present invention includes a lead frame in which a light emitting element is installed, a wire that electrically connects a power supply unit provided in the lead frame and the light emitting element, and a light transmitting property in which a phosphor is dispersed. And a resin. With such a configuration, a light emitting device having high luminous efficiency and good color rendering properties tends to be obtained. Here, it is preferable that the light emitting element is installed in the light transmitting resin. In this case, there is a tendency that a higher color rendering property can be obtained with higher luminous efficiency.

  The light-emitting device of the present invention includes a light guide for propagating light emitted from the light-emitting element, and a light-transmitting resin in which the phosphor is dispersed at one end of the light guide. It can be set as the structure which the light which propagated the body is irradiated to a fluorescent substance from the end of a light guide. With such a configuration, a light emitting device having high luminous efficiency and good color rendering properties tends to be obtained. Here, for example, an optical fiber can be used as the light guide.

Example 1
In FIG. 1, the typical side view of the light-emitting device of Example 1 of this invention is shown. Here, the light-emitting device of Example 1 is a light-emitting element composed of a light-emitting diode (LED) that emits light having a peak wavelength of 460 nm mounted with a silver paste inside a concave cup 101 provided at one end of a lead frame 100. 102 and a core of semiconductor nanoparticles (Zn _0.62 Cd _0.38 Se) having a peak wavelength of 525 nm and a particle diameter of 5 nm dispersed in a light-transmitting resin 103 made of a light-transmitting silicone resin, and the periphery thereof. And a core of semiconductor nanoparticles (Zn _0.62 Cd _0.38 Se) having a peak wavelength of 585 nm and a particle diameter of 10 nm, and a layer thickness formed around the first phosphor comprising a clad (ZnS) having a layer thickness of 1 μm a second phosphor consisting the cladding (ZnS) consisting of 1 [mu] m, the particle diameter at the peak wavelength of 650nm is 8nm semiconductor nanoparticles (Zn _0.9 a phosphor 105 comprising a core of d _0.1 Se) and the third phosphor consisting cladding (ZnS) consisting of layer thickness 1μm formed therearound, contains.

  Here, each of the first phosphor, the second phosphor, and the third phosphor was produced by a hot soap method. That is, a core was prepared by a hot soap method by mixing a precursor serving as a Zn source, a precursor serving as a Cd source, and a precursor serving as an Se source so as to have a composition ratio of the core. Moreover, the precursor used as a Zn source and the precursor used as a S source were mixed so that it might become a composition ratio of a cladding, and the cladding was produced by the hot soap method.

  The pair of lead frames 100 is provided with a power supply unit (not shown), and these lead frames 100 are electrically connected to the light emitting element 102 by wires 106 made of, for example, gold wires. Further, in order to seal these members, there is a light-transmitting resin 104 made of a shell-shaped light-transmitting silicone resin having a lens function capable of efficiently taking out light emitted from the phosphor 105 to the outside. Is provided.

  In the light emitting device of Example 1, the dispersion ratios of the first phosphor, the second phosphor, and the third phosphor are x = 0.3 and y = 0.3 on the chromaticity diagram. To be adjusted.

  FIG. 2 shows a spectrum of light emitted from the light emitting device of Example 1 described above. As shown in FIG. 2, the spectrum of the light emitted from the light emitting device of Example 1 shows the peak of each light emitted from the light emitting element 102, the first phosphor, the second phosphor, and the third phosphor. Wavelength appears. Therefore, the light emitting device of Example 1 includes the emission color from the light emitting element 102, the emission color from the first phosphor, the emission color from the second phosphor, and the emission color from the third phosphor. It can be seen that mixed color light is emitted. The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 60 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Since the absolute value of the difference is 65 nm, the standard deviation of the absolute value of these differences is 15 nm or less, and the peak wavelengths of the light emitted from the first phosphor, the second phosphor, and the third phosphor are substantially equal. It can be seen that they are arranged at intervals. Moreover, the half width of the peak of light emitted from the first phosphor, the second phosphor, and the third phosphor is 30 nm or more and 40 nm or less.

  Table 1 shows Stokes loss (%), theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 1. As shown in Table 1, the Stokes loss of the light emitting device of Example 1 is 17%, the theoretical limit efficiency is 235 (lm / W), the average color rendering index (Ra) is 94, and the special color rendering evaluation The number (R9) is 93.

  Table 1 shows the ratio of the light intensity of each peak wavelength of the first phosphor, the second phosphor, and the third phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 1, the intensity of light at the peak wavelength of the first phosphor is 0.79 relative to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 0.88, and the intensity of light having a peak wavelength of the third phosphor is 0.92.

(Example 2)
First, the particle diameter and / or composition of the core of the semiconductor nanoparticles in Example 1 is changed as appropriate, and light from the light emitting element 102 in Example 1 is irradiated to emit light having the following peak wavelengths, respectively. The light emitting device of Example 2 having the same configuration as that of Example 1 is manufactured except that the phosphor 105 composed of the phosphor, the second phosphor, the third phosphor, and the fourth phosphor is used.
First phosphor: peak wavelength 510 nm
Second phosphor: peak wavelength 555 nm
Third phosphor: peak wavelength 600 nm
Fourth phosphor: peak wavelength 650 nm
Table 1 shows Stokes loss (%), theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 2. As shown in Table 1, the Stokes loss of the light emitting device of Example 2 is 16%, the theoretical limit efficiency is 245 (lm / W), the average color rendering index (Ra) is 90, and the special color rendering evaluation The number (R9) is 86.

  Table 1 shows the light intensity of each of the first phosphor, the second phosphor, the third phosphor, and the fourth phosphor with respect to the light intensity (1.00) of the peak wavelength of the light emitting element 102. The ratio of As shown in Table 1, the intensity of light at the peak wavelength of the first phosphor is 0.68 relative to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 0.68, the intensity of light having a peak wavelength of the third phosphor is 0.76, and the intensity of light having a peak wavelength of the fourth phosphor is 0.63.

  Further, when the spectrum of the light emitted from the light emitting device of Example 2 was examined, the spectrum of the light emitted from the light emitting device of Example 2 includes the light emitting element 102, the first phosphor, the second phosphor, Since the peak wavelength of each light emitted from the third phosphor and the fourth phosphor appears, the light emitting device of Example 2 emits the light emitted from the light emitting element 102 and the light emitted from the first phosphor. It can be seen that light of a mixed color of the color, the emission color from the second phosphor, the emission color from the third phosphor, and the emission color from the fourth phosphor is emitted.

  The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 45 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Since the absolute value of the difference between the peak wavelength of the adjacent third phosphor and the peak wavelength of the fourth phosphor is 50 nm, the standard deviation of the absolute value of these differences is 15 nm or less. The peak wavelengths of the light emitted from the first phosphor, the second phosphor, the third phosphor and the fourth phosphor are arranged at approximately equal intervals.

(Example 3)
First, the particle diameter and / or composition of the core of the semiconductor nanoparticles in Example 1 is changed as appropriate, and light from the light emitting element 102 in Example 1 is irradiated to emit light having the following peak wavelengths, respectively. The light emitting device of Example 3 having the same configuration as that of Example 1 is manufactured except that the phosphor 105 composed of the phosphor, the second phosphor, the third phosphor, the fourth phosphor, and the fifth phosphor is used. .
First phosphor: peak wavelength 500 nm
Second phosphor: peak wavelength 535 nm
Third phosphor: peak wavelength 575 nm
Fourth phosphor: peak wavelength 610 nm
Fifth phosphor: peak wavelength 650 nm
Table 1 shows Stokes loss (%), theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 3. As shown in Table 1, the Stokes loss of the light emitting device of Example 3 is 16%, the theoretical limit efficiency is 245 (lm / W), the average color rendering index (Ra) is 89, and the special color rendering evaluation The number (R9) is 88.

  Table 1 shows the peaks of the first phosphor, the second phosphor, the third phosphor, the fourth phosphor, and the fifth phosphor with respect to the light intensity (1.00) of the peak wavelength of the light emitting element 102. The ratio of the intensity of light of the wavelength is shown. As shown in Table 1, the intensity of light at the peak wavelength of the first phosphor is 0.57 with respect to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of the light with the wavelength is 0.56, the intensity of the light with the peak wavelength of the third phosphor is 0.58, the intensity of the light with the peak wavelength of the fourth phosphor is 0.64, and the fifth The intensity of light at the peak wavelength of the phosphor is 0.59.

  Further, when the spectrum of the light emitted from the light emitting device of Example 3 was examined, the spectrum of the light emitted from the light emitting device of Example 3 includes the light emitting element 102, the first phosphor, the second phosphor, Since the peak wavelengths of the light emitted from the third phosphor, the fourth phosphor, and the fifth phosphor appear, the light emitting device of Example 3 has the emission color from the light emitting element 102, the first A color mixture of the emission color from the phosphor, the emission color from the second phosphor, the emission color from the third phosphor, the emission color from the fourth phosphor, and the emission color from the fifth phosphor It can be seen that light is emitted.

  The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 35 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Is 40 nm, the absolute value of the difference between the peak wavelength of the adjacent third phosphor and the peak wavelength of the fourth phosphor is 35 nm, the peak wavelength of the adjacent fourth phosphor and the fifth phosphor Since the absolute value of the difference from the peak wavelength is 40 nm, the standard deviation of the absolute value of these differences is 15 nm or less. The first phosphor, the second phosphor, the third phosphor, and the fourth phosphor The peak wavelengths of the light emitted from the fifth phosphor are arranged at substantially equal intervals.

Example 4
First, the particle diameter and / or composition of the core of the semiconductor nanoparticles in Example 1 is changed as appropriate, and light from the light emitting element 102 in Example 1 is irradiated to emit light having the following peak wavelengths, respectively. Example 4 of Example 4 having the same configuration as Example 1 except that the phosphor 105 composed of the phosphor, the second phosphor, the third phosphor, the fourth phosphor, the fifth phosphor, and the sixth phosphor is used. A light emitting device is manufactured.
First phosphor: peak wavelength 490 nm
Second phosphor: peak wavelength 525 nm
Third phosphor: peak wavelength 555 nm
Fourth phosphor: peak wavelength 585 nm
Fifth phosphor: peak wavelength 620 nm
Sixth phosphor: peak wavelength 650 nm
Table 1 shows Stokes loss (%), theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 4. As shown in Table 1, the Stokes loss of the light emitting device of Example 4 is 16%, the theoretical limit efficiency is 245 (lm / W), the average color rendering index (Ra) is 88, and the special color rendering evaluation The number (R9) is 94.

  Table 1 shows that the first phosphor, the second phosphor, the third phosphor, the fourth phosphor, the fifth phosphor, and the sixth fluorescence with respect to the light intensity (1.00) of the peak wavelength of the light emitting element 102. The ratio of the light intensity of each peak wavelength of the body is shown. As shown in Table 1, the intensity of light at the peak wavelength of the first phosphor is 0.53 with respect to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of the light of the wavelength is 0.46, the intensity of the light of the peak wavelength of the third phosphor is 0.48, the intensity of the light of the peak wavelength of the fourth phosphor is 0.57, The intensity of light at the peak wavelength of the phosphor is 0.54, and the intensity of light at the peak wavelength of the sixth phosphor is 0.53.

  Further, when the spectrum of the light emitted from the light emitting device of Example 4 was examined, the spectrum of the light emitted from the light emitting device of Example 4 includes the light emitting element 102, the first phosphor, the second phosphor, Since the peak wavelength of each light emitted from the third phosphor, the fourth phosphor, the fifth phosphor, and the sixth phosphor appears, the light emitting device of Example 4 emits light from the light emitting element 102. Color, emission color from the first phosphor, emission color from the second phosphor, emission color from the third phosphor, emission color from the fourth phosphor, and emission from the fifth phosphor It can be seen that light of a mixed color of the color and the emission color from the sixth phosphor is emitted.

  The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 35 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. The absolute value of the difference between the peak wavelength of the adjacent third phosphor and the peak wavelength of the fourth phosphor is 30 nm, the peak value of the adjacent fourth phosphor and the fifth phosphor The absolute value of the difference from the peak wavelength of 35 nm is 35 nm, and the absolute value of the difference between the peak wavelength of the adjacent fifth phosphor and the peak wavelength of the sixth phosphor is 30 nm. Standard deviation is 15 nm or less, and the peak wavelengths of the light emitted from the first phosphor, the second phosphor, the third phosphor, the fourth phosphor, the fifth phosphor, and the sixth phosphor are substantially equally spaced. Is arranged.

(Comparative Example 1)
First, the particle diameter and / or composition of the core of the semiconductor nanoparticles in Example 1 is changed as appropriate, and light from the light emitting element 102 in Example 1 is irradiated to emit light having the following peak wavelengths, respectively. A light emitting device of Comparative Example 1 having the same configuration as that of Example 1 is manufactured except that the phosphor 105 including the phosphor and the second phosphor is used.
First phosphor: peak wavelength 555 nm
Second phosphor: peak wavelength 650 nm
Table 1 shows Stokes loss (%), theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Comparative Example 1. As shown in Table 1, the Stokes loss of the light emitting device of Comparative Example 1 is 20%, the theoretical limit efficiency is 202 (lm / W), the average color rendering index (Ra) is 64, and the special color rendering evaluation The number (R9) is 0 or less.

  Table 1 shows the ratio of the light intensity of each peak wavelength of the first phosphor and the second phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 1, the intensity of light at the peak wavelength of the first phosphor is 1.19 relative to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of the wavelength light is 1.68.

  As shown in Table 1, in the light emitting device of Comparative Example 1 that emits only three types of light having different peak wavelengths, the Stokes loss is 20% and the theoretical limit efficiency is 200 (lm / W). The light emitting devices of Examples 1 to 4 that emit four or more types of light having different peak wavelengths have a Stokes loss reduced by about 20% compared to the light emitting device of Comparative Example 1, and the theoretical limit efficiency is 235 to 245 (lm / W). ).

  Further, from the viewpoint of reducing the Stokes loss and increasing the theoretical limit efficiency, it is preferable to have five or more types of light emission. However, if the number is more than five, both the reduction of the Stokes loss and the increase of the theoretical limit efficiency are saturated. ing.

  As shown in Table 1, in the light emitting device of Comparative Example 1 in which three types of light having different peak wavelengths are emitted, the average color rendering index (Ra) is 64 and the special color rendering index (R9) is 0. In the light emitting devices of Examples 1 to 4 which emit four or more types of light having different peak wavelengths, both the average color rendering index (Ra) and the special color rendering index (R9) are 86 to 94, which are very low. It can be seen that it has high color rendering properties.

  From the above results, in the light-emitting devices of Examples 1 to 4, in which the light emitted from the light-emitting element and three or more types of light emitted from the phosphor are combined to emit four or more types of light having different peak wavelengths. It can be seen that efficiency and color rendering are good.

  The above tendency becomes remarkable when the half width of the intensity at the peak wavelength of the light emitted from the phosphor is narrow. Thus, in order to narrow the half width of the intensity at the peak wavelength of the light emitted from the phosphor, when using nanoparticles made of a semiconductor as used in the light emitting devices of Examples 1 to 4, In some cases, a phosphor using light emission caused by transition between 4f levels of rare earth is used.

  It will be described in detail how the intensity of light emitted from the phosphor required for obtaining white light is determined. FIG. 3 shows a two-degree color matching function x (λ), y (λ), z (λ) that is a correlation between the wavelength of light and the sensitivity with which the human eye perceives light of that wavelength as red, green, and blue. Indicates. For example, how a human feels the color of a certain fluorescence spectrum S (λ) is determined by the red component X = Σ (x (λ) * S (λ) Δλ) and the green component Y = Σ (x (λ)). * S (λ) Δλ) and blue component Z = Σ (x (λ) * S (λ) Δλ). White when all XYZ proportions are equal. When white light is obtained using an RGB type phosphor, a red phosphor and a green phosphor each having a peak wavelength around the peaks of the color matching functions x (λ), y (λ), and z (λ). In general, blue phosphors are used. In such a configuration, the amounts of the red component X, the green component Y, and the blue component Z of each phosphor are determined, so that the emission intensity ratio of the phosphors required to obtain white light is unambiguous. It will be decided.

  However, it can be seen from FIG. 3 that there are some widths in the wavelength range that the human eye perceives as red, green, and blue. For example, in addition to a red phosphor, a green phosphor, and a blue phosphor, and adding a yellow phosphor that is an intermediate color between them, the yellow wavelength range is perceived by the human eye as a red component and a green component. The more yellow phosphors are inserted, the less red and green phosphors are needed to obtain white light.

  In other words, in the case of obtaining white light with a mixed color of emitted light, in addition to the phosphors emitting red light, green light, and blue light, which are the three primary colors of light (red phosphor, green phosphor, and blue phosphor), respectively. When the phosphors that emit light of these intermediate colors (intermediate color phosphors) are mixed in a complementary color, part of the red light, green light, and blue light is replaced with the intermediate color light, and the red phosphor and the green phosphor In addition, since the spectrum becomes a broad spectrum having components in the entire visible range from the discrete spectrum when only the blue phosphor is used, the color balance is improved and the color rendering is high. In addition, since the red phosphor component having a large Stokes loss is replaced with the intermediate color phosphor component, the Stokes loss can be reduced and the configuration has a high theoretical limit efficiency.

(Example 5)
First, the particle diameter and / or composition of the core of the semiconductor nanoparticles in Example 1 is changed as appropriate, and light from the light emitting element 102 in Example 1 is irradiated to emit light having the following peak wavelengths, respectively. The light emitting device of Example 5 having the same configuration as that of Example 1 is manufactured except that the phosphor 105 including the phosphor, the second phosphor, and the third phosphor is used.
First phosphor: peak wavelength 515 nm
Second phosphor: peak wavelength 600 nm
Third phosphor: peak wavelength 650 nm
Table 2 shows the average color rendering index (Ra) and special color rendering index (R9) of the light emitting device of Example 5. As shown in Table 2, the average color rendering index (Ra) of the light emitting device of Example 5 is 60, and the special color rendering index (R9) is 22.

  Table 2 shows the ratio of the light intensity of each peak wavelength of the first phosphor, the second phosphor, and the third phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 2, the intensity of light at the peak wavelength of the first phosphor is 1.35 with respect to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of the light having the wavelength is 1.00, and the intensity of the light having the peak wavelength of the third phosphor is 0.90.

  FIG. 4 shows a spectrum of light emitted from the light emitting device of Example 5. As shown in FIG. 4, the spectrum of the light emitted from the light emitting device of Example 5 shows the peak of each light emitted from the light emitting element 102, the first phosphor, the second phosphor, and the third phosphor. Since the wavelength appears, the light-emitting device of Example 5 has the emission color from the light-emitting element 102, the emission color from the first phosphor, the emission color from the second phosphor, and the third phosphor. It can be seen that light of a mixed color with the light emission color is emitted.

  The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 85 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Is an absolute value of 50 nm, and the standard deviation of the absolute value of these differences is greater than 15 nm. Therefore, the peak wavelength of light emitted from the first phosphor, the second phosphor, and the third phosphor is They are not arranged at substantially equal intervals.

(Example 6)
First, the particle diameter and / or composition of the core of the semiconductor nanoparticles in Example 1 is changed as appropriate, and light from the light emitting element 102 in Example 1 is irradiated to emit light having the following peak wavelengths, respectively. The light emitting device of Example 6 having the same configuration as that of Example 1 is manufactured except that the phosphor 105 including the phosphor, the second phosphor, and the third phosphor is used.
First phosphor: peak wavelength 500 nm
Second phosphor: peak wavelength 610 nm
Third phosphor: peak wavelength 650 nm
Table 2 shows the average color rendering index (Ra) and special color rendering index (R9) of the light emitting device of Example 6. As shown in Table 2, the average color rendering index (Ra) of the light emitting device of Example 6 is 10, and the special color rendering index (R9) is −60.

  Table 2 shows the ratio of the light intensity of each peak wavelength of the first phosphor, the second phosphor, and the third phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 2, the intensity of light at the peak wavelength of the first phosphor is 3.94 relative to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 2.24, and the intensity of light having a peak wavelength of the third phosphor is 1.00.

  Further, when the spectrum of the light emitted from the light emitting device of Example 6 was examined, the spectrum of the light emitted from the light emitting device of Example 6 showed that the light emitting element 102, the first phosphor, the second phosphor, and Since the peak wavelength of each light emitted from the third phosphor appears, the light emitting device of Example 6 has the emission color from the light emitting element 102, the emission color from the first phosphor, and the second. It can be seen that light of a mixed color of the emission color from the phosphor and the emission color from the third phosphor is emitted.

  The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 110 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. And the standard deviation of the absolute value of these differences is greater than 15 nm. Therefore, the peak wavelength of light emitted from the first phosphor, the second phosphor, and the third phosphor is They are not arranged at substantially equal intervals.

  As is apparent from comparison between the average color rendering index (Ra) and the special color rendering index (R9) of the light emitting device of Example 1 in Table 1 and the light emitting devices of Examples 5 to 6 in Table 2, respectively. The average color rendering index (Ra) of the light emitting device of Example 1 in which the peak wavelengths of the light emitted from the phosphors are arranged at substantially equal intervals even if the number of light emitting elements and phosphors constituting the same is the same It can also be seen that the special color rendering index (R9) is significantly superior to the light emitting devices of Examples 5 to 6 in which the peak wavelengths of the light emitted from the phosphors are not arranged at substantially equal intervals. Therefore, in the light emitting device of the present invention, it is preferable that the peak wavelengths of the light emitted from the phosphor are arranged at substantially equal intervals.

  In addition, the peak wavelength of light to be emitted without using the quantum effect by changing the particle diameter of the nanoparticles, including semiconductor nanoparticles, as used in the light emitting devices of Examples 1 to 6 above. A phosphor capable of continuously changing is a preferred form in the present invention.

  Similarly to the phosphor containing the semiconductor nanoparticles described above, the peak wavelength of the emitted light can be continuously changed by changing the mixed crystal ratio of the semiconductor without using the quantum effect. A phosphor containing a mixed crystal is also a preferred form in the present invention.

As a phosphor capable of continuously changing the peak wavelength of emitted light by changing the mixed crystal ratio of the semiconductor, for example, it is represented by a composition formula of Cd _x Zn _{1 -x} S _y Se _{1 -y.} A semiconductor can be used, and the peak wavelength of emitted light can be controlled by changing x and / or y that determines the composition ratio represented by this composition formula.

In the present invention, in addition to the above-described phosphor, a phosphor in which a transition element or a rare earth element is dispersed in an oxide or sulfide can be used. Examples of such a phosphor include a red phosphor represented by the formula Y ₂ O ₃ : Eu, a green phosphor represented by the formula ZnS: Cu, Al, or (Ba, Mg) Al ₁₀ O ₁₇ : Eu, Mn. Or a blue phosphor represented by the formula (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) ₆ O ₁₂ : Eu or (Ba, Mg) Al ₁₀ O ₁₇ : Eu can be used.

(Example 7)
A first phosphor composed of a core of semiconductor nanoparticles (ZnSe) having a peak wavelength of 510 nm and a particle diameter of 10 nm and a clad (ZnS) having a thickness of 1 μm formed around the core, and a particle diameter of 570 nm at a peak wavelength A second phosphor comprising a core of 8 nm semiconductor nanoparticles (Zn _0.62 Cd _0.38 Se) and a clad (ZnS) having a thickness of 1 μm formed around the core, and a semiconductor having a peak wavelength of 630 nm and a particle diameter of 7 nm Example 1 except that a phosphor 105 composed of a core of a nanoparticle (Zn _0.9 Cd _0.1 Se) and a third phosphor composed of a cladding (ZnS) having a layer thickness of 1 μm formed around the core is used. A light emitting device of Example 7 having the same configuration is manufactured.

  In the light emitting device of Example 7, the dispersion ratios of the first phosphor, the second phosphor, and the third phosphor are x = 0.3 and y = 0.3 on the chromaticity diagram. To be adjusted.

  FIG. 5 shows a spectrum of light emitted from the light emitting device of Example 7 described above. As shown in FIG. 5, the spectrum of the light emitted from the light emitting device of Example 7 shows the peak of each light emitted from the light emitting element 102, the first phosphor, the second phosphor, and the third phosphor. Wavelength appears. Therefore, the light emitting device of Example 7 includes the emission color from the light emitting element 102, the emission color from the first phosphor, the emission color from the second phosphor, and the emission color from the third phosphor. It can be seen that mixed color light is emitted. The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 60 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Since the absolute value of the difference is 60 nm, the standard deviation of the absolute value of these differences is 15 nm or less. Therefore, the peak wavelength of the light emitted from the first phosphor, the second phosphor, and the third phosphor is approximately It is arranged at equal intervals. Moreover, the half width of the peak of light emitted from the first phosphor, the second phosphor, and the third phosphor is 30 nm or more and 40 nm or less.

  Table 3 shows the theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 7. As shown in Table 3, the theoretical limit efficiency of the light emitting device of Example 7 is 260 (lm / W), the average color rendering index (Ra) is 90, and the special color rendering index (R9) is 93. .

  Table 3 shows the ratio of the light intensity of each peak wavelength of the first phosphor, the second phosphor, and the third phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 3, the intensity of light at the peak wavelength of the first phosphor is 0.54 with respect to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 0.72, and the intensity of light having a peak wavelength of the third phosphor is 0.64.

  In the range of 430 nm to 760 nm that can be felt with eyes as in the light emitting device of Example 7, in addition to the light emitting element and the phosphor that respectively emit red light, green light, and blue light, which are the three primary colors of light, By adding a phosphor that emits light of the intermediate color, the average color rendering index (Ra) is as high as 90.

  Further, as in the light-emitting device of Example 7, a special color rendering index indicating how a red object is seen by having at least one peak wavelength in the range of 560 nm to 610 nm and the range of 610 nm to less than 650 nm, respectively ( R9) can be adjusted.

  For example, a red object can be obtained by setting the spectral shape of the component from yellow-red to red, that is, the intensity of light having a peak wavelength of 570 nm and the intensity of light having a peak wavelength of 630 nm as shown in FIG. As for the special color rendering index (R9) indicating the appearance of, a very high value of 93 was obtained. This value indicates that the light-emitting device of Example 7 is sufficiently applicable not only to general illumination but also to medical illumination in which the red appearance is regarded as important.

  Therefore, in the configuration of the light emitting device of Example 7, it is possible to obtain a device having both an average color rendering index (Ra) and a red special color rendering index (R9) that are better than the conventional one.

  The value of the special color rendering index (R9) indicating the appearance of the red object can be changed in any way by appropriately changing the ratio of the intensity of light having a peak wavelength of 570 nm and the intensity of light having a peak wavelength of 630 nm. it can.

(Example 8)
Example except that the ratio of the light intensity of each peak wavelength of the first phosphor, the second phosphor and the third phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102 was appropriately changed. A light emitting device of Example 8 having the same configuration as that of No. 7 is manufactured.

  In the light emitting device of Example 8, the dispersion ratios of the first phosphor, the second phosphor, and the third phosphor are x = 0.3 and y = 0.3 on the chromaticity diagram. To be adjusted.

  FIG. 6 shows a spectrum of light emitted from the light emitting device of Example 8 described above. As shown in FIG. 6, the spectrum of the light emitted from the light emitting device of Example 8 shows the peak of each light emitted from the light emitting element 102, the first phosphor, the second phosphor, and the third phosphor. Wavelength appears. Therefore, the light emitting device of Example 8 includes the emission color from the light emitting element 102, the emission color from the first phosphor, the emission color from the second phosphor, and the emission color from the third phosphor. It can be seen that mixed color light is emitted. The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 60 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Since the absolute value of the difference is 60 nm, the standard deviation of the absolute value of these differences is 15 nm or less. Therefore, the peak wavelength of the light emitted from the first phosphor, the second phosphor, and the third phosphor is approximately It is arranged at equal intervals. Moreover, the half width of the peak of light emitted from the first phosphor, the second phosphor, and the third phosphor is 30 nm or more and 40 nm or less.

  Table 3 shows the theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 8. As shown in Table 3, the theoretical limiting efficiency of the light emitting device of Example 8 is 280 (lm / W), the average color rendering index (Ra) is 80, and the special color rendering index (R9) is 25. .

  Table 3 shows the ratio of the light intensity of each peak wavelength of the first phosphor, the second phosphor, and the third phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 3, the intensity of light at the peak wavelength of the first phosphor is 0.38 relative to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 0.83, and the intensity of light having a peak wavelength of the third phosphor is 0.48.

  Note that the light emitting device of Example 8 also has at least one peak wavelength in the range of 560 nm to 610 nm and in the range of 610 nm to less than 650 nm, respectively. R9) can be adjusted.

Example 9
The semiconductor nanoparticle core particle diameter and / or composition in Example 7 is changed as appropriate, and light from the light emitting element 102 in Example 7 is irradiated to emit light having the following peak wavelengths, respectively. The light-emitting device of Example 9 having the same configuration as that of Example 7 is manufactured except that the phosphor 105 including the phosphor, the second phosphor, and the third phosphor is used.
First phosphor: peak wavelength 540 nm
Second phosphor: peak wavelength 610 nm
Third phosphor: peak wavelength 650 nm
Table 3 shows the theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 9. As shown in Table 3, the theoretical limiting efficiency of the light emitting device of Example 9 is 240 (lm / W), the average color rendering index (Ra) is 75, and the special color rendering index (R9) is 23. .

  Table 3 shows the ratio of the light intensity of each peak wavelength of the first phosphor, the second phosphor, and the third phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 3, the intensity of light at the peak wavelength of the first phosphor is 0.78 relative to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 0.53, and the intensity of light having a peak wavelength of the third phosphor is 0.49.

  Further, when the spectrum of the light emitted from the light emitting device of Example 9 was examined, the spectrum of the light emitted from the light emitting device of Example 9 showed that the light emitting element 102, the first phosphor, the second phosphor, and Since the peak wavelength of each light emitted from the third phosphor appears, the light emitting device of Example 9 has the emission color from the light emitting element 102, the emission color from the first phosphor, the second It can be seen that light of a mixed color of the emission color from the phosphor and the emission color from the third phosphor is emitted.

  The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 70 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. And the standard deviation of the absolute value of these differences is greater than 15 nm. Therefore, the peak wavelength of light emitted from the first phosphor, the second phosphor, and the third phosphor is They are not arranged at substantially equal intervals.

(Example 10)
The semiconductor nanoparticle core particle diameter and / or composition in Example 7 is changed as appropriate, and light from the light emitting element 102 in Example 7 is irradiated to emit light having the following peak wavelengths, respectively. The light emitting device of Example 10 having the same configuration as that of Example 7 is manufactured except that the phosphor 105 including the phosphor, the second phosphor, and the third phosphor is used.
First phosphor: peak wavelength 510 nm
Second phosphor: peak wavelength 555 nm
Third phosphor: peak wavelength 600 nm
Table 3 shows the theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 10. As shown in Table 3, the theoretical limit efficiency of the light emitting device of Example 10 is 290 (lm / W), the average color rendering index (Ra) is 75, and the special color rendering index (R9) is 0 or less. is there.

  Table 3 shows the ratio of the light intensity of each peak wavelength of the first phosphor, the second phosphor, and the third phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 3, the intensity of light at the peak wavelength of the first phosphor is 0.43 with respect to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 0.44, and the intensity of light having a peak wavelength of the third phosphor is 0.73.

  Further, when the spectrum of the light emitted from the light emitting device of Example 10 was examined, the spectrum of the light emitted from the light emitting device of Example 10 includes the light emitting element 102, the first phosphor, the second phosphor, and Since the peak wavelength of each light emitted from the third phosphor appears, the light emitting device of Example 10 has the emission color from the light emitting element 102, the emission color from the first phosphor, and the second. It can be seen that light of a mixed color of the emission color from the phosphor and the emission color from the third phosphor is emitted.

  The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 45 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Is 45 nm, and the standard deviation of the absolute value of these differences is 15 nm or less. Therefore, the peak wavelength of light emitted from the first phosphor, the second phosphor, and the third phosphor is approximately It is arranged at equal intervals.

(Comparative Example 2)
The semiconductor nanoparticle core particle diameter and / or composition in Example 7 is changed as appropriate, and light from the light emitting element 102 in Example 7 is irradiated to emit light having the following peak wavelengths, respectively. A light emitting device of Comparative Example 2 having the same configuration as that of Example 7 is manufactured except that the phosphor 105 including the phosphor and the second phosphor is used.
First phosphor: peak wavelength 520 nm
Second phosphor: peak wavelength 600 nm
Table 3 shows the theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Comparative Example 2. As shown in Table 3, the theoretical limit efficiency of the light emitting device of Comparative Example 2 is 280 (lm / W), the average color rendering index (Ra) is 70, and the special color rendering index (R9) is 0 or less. is there.

  Table 3 shows the ratio of the light intensity of each peak wavelength of the first phosphor and the second phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 3, the intensity of light at the peak wavelength of the first phosphor is 0.80 with respect to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of the wavelength light is 0.90.

(Comparative Example 3)
The semiconductor nanoparticle core particle diameter and / or composition in Example 7 is changed as appropriate, and light from the light emitting element 102 in Example 7 is irradiated to emit light having the following peak wavelengths, respectively. A light emitting device of Comparative Example 3 having the same configuration as that of Example 7 is manufactured except that the phosphor 105 composed of the phosphor and the second phosphor is used.
First phosphor: peak wavelength 540 nm
Second phosphor: peak wavelength 650 nm
Table 3 shows the theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Comparative Example 3. As shown in Table 3, the theoretical limit efficiency of the light emitting device of Comparative Example 3 is 160 (lm / W), the average color rendering index (Ra) is 40, and the special color rendering index (R9) is 0 or less. is there.

  Table 3 shows the ratio of the light intensity of each peak wavelength of the first phosphor and the second phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 3, the intensity of light at the peak wavelength of the first phosphor is 0.56 with respect to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of the wavelength light is 0.50.

  As shown in Table 3, the light emitting devices of Examples 7 to 10 that emit four or more types of light having different peak wavelengths are the same as the light emitting devices of Comparative Examples 2 to 3 that emit only three types of light having different peak wavelengths. In comparison, the average color rendering index (Ra) shows a good value.

  As shown in Table 3, in the light emitting devices of Examples 7 to 9 having at least two peak wavelengths in the wavelength range from yellow-red to red, the phosphor emits light with respect to the intensity of light emitted from the light-emitting element. By appropriately changing the ratio of the intensity of the emitted light, the values of theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) can be adjusted.

  Comparing the light emitting devices of Example 7 and Example 8, when the special color rendering index (R9) is 25, the theoretical limit efficiency can be 280 (lm / W) (Example 8). On the other hand, if the theoretical limit efficiency is 260 (lm / W), the special color rendering index (R9) can be set to 93 (Example 7).

  When the special color rendering index (R9), which is an indicator of the appearance of red, is high, the red component increases and the Stokes loss increases accordingly. Therefore, the theoretical limit efficiency and the special color rendering index (R9) are in a contradictory relationship. However, even when the special color rendering index (R9) is increased and the theoretical limit efficiency is sacrificed slightly, the theoretical limit efficiency is the blue light having a peak wavelength of 460 nm shown as a conventional example in the background art column. A value higher than that of a structure in which a light emitting element that emits light and a yellow phosphor is combined can be obtained. Therefore, it can be seen that the light-emitting devices of Examples 7 to 10 are superior in both theoretical limit efficiency and color rendering properties as compared with the conventional example.

(Example 11)
A first phosphor composed of a semiconductor nanoparticle (ZnSe) core having a peak wavelength of 510 nm and a particle diameter of 10 nm and a clad (ZnS) having a thickness of 1 μm formed around the core, and a particle diameter of 535 nm at a peak wavelength of 565 nm. A second phosphor composed of a core of 7.8 nm semiconductor nanoparticles (Zn _0.62 Cd _0.38 Se) and a clad (ZnS) having a thickness of 1 μm formed around the core, and a particle diameter of 6 at a peak wavelength of 615 nm Except for using a phosphor 105 composed of a core of .5 nm semiconductor nanoparticles (Zn _0.9 Cd _0.1 Se) and a third phosphor composed of a cladding (ZnS) having a layer thickness of 1 μm formed around the core. The light emitting device of Example 11 having the same configuration as that of Example 1 is manufactured.

  In the light emitting device of Example 11, the dispersion ratios of the first phosphor, the second phosphor, and the third phosphor are x = 0.3 and y = 0.3 on the chromaticity diagram. To be adjusted.

  FIG. 7 shows a spectrum of light emitted from the light emitting device of Example 11 described above. As shown in FIG. 7, the spectrum of the light emitted from the light emitting device of Example 11 shows the peak of each light emitted from the light emitting element 102, the first phosphor, the second phosphor, and the third phosphor. Wavelength appears. Therefore, the light emitting device of Example 11 includes the emission color from the light emitting element 102, the emission color from the first phosphor, the emission color from the second phosphor, and the emission color from the third phosphor. It can be seen that mixed color light is emitted. The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 55 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Since the absolute value of the difference is 50 nm, the standard deviation of the absolute value of these differences is 15 nm or less. Therefore, the peak wavelength of the light emitted from the first phosphor, the second phosphor, and the third phosphor is approximately It is arranged at equal intervals.

  Table 4 shows the theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 11. As shown in Table 4, the theoretical limiting efficiency of the light emitting device of Example 11 is 280 (lm / W), the average color rendering index (Ra) is 85, and the special color rendering index (R9) is 25. .

  Table 4 shows the ratio of the light intensity of each peak wavelength of the first phosphor, the second phosphor, and the third phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 4, the intensity of light at the peak wavelength of the first phosphor is 0.56 with respect to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 0.50, and the intensity of light having a peak wavelength of the third phosphor is 0.71.

(Example 12)
The particle diameter and / or composition of the core of the semiconductor nanoparticles in Example 11 is appropriately changed, and light having the following peak wavelengths is emitted by irradiating light from the light emitting element 102 in Example 11. The light emitting device of Example 12 having the same configuration as that of Example 11 is manufactured except that the phosphor 105 including the phosphor, the second phosphor, and the third phosphor is used.
First phosphor: peak wavelength 510 nm
Second phosphor: peak wavelength 565 nm
Third phosphor: peak wavelength 620 nm
Table 4 shows the theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 12. As shown in Table 4, the theoretical limiting efficiency (lm / W) of the light emitting device of Example 12 is 265 (lm / W), the average color rendering index (Ra) is 90, and the special color rendering index (R9). ) Is 70.

  Table 4 shows the ratio of the light intensity of each peak wavelength of the first phosphor, the second phosphor, and the third phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 4, the intensity of light at the peak wavelength of the first phosphor is 0.56 with respect to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 0.61, and the intensity of light having a peak wavelength of the third phosphor is 0.68.

  Further, when the spectrum of the light emitted from the light emitting device of Example 12 was examined, the spectrum of the light emitted from the light emitting device of Example 12 showed that the light emitting element 102, the first phosphor, the second phosphor, and Since the peak wavelength of each light emitted from the third phosphor appears, the light emitting device of Example 12 has the emission color from the light emitting element 102, the emission color from the first phosphor, the second It can be seen that light of a mixed color of the emission color from the phosphor and the emission color from the third phosphor is emitted.

  The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 55 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Since the absolute value of the difference is 55 nm and the standard deviation of the absolute value of these differences is 15 nm or less, the peak wavelength of the light emitted from the first phosphor, the second phosphor and the third phosphor is approximately It is arranged at equal intervals.

(Example 13)
The particle diameter and / or composition of the core of the semiconductor nanoparticles in Example 11 is appropriately changed, and light having the following peak wavelengths is emitted by irradiating light from the light emitting element 102 in Example 11. The light emitting device of Example 13 having the same configuration as that of Example 11 is manufactured except that the phosphor 105 including the phosphor, the second phosphor, and the third phosphor is used.
First phosphor: peak wavelength 515 nm
Second phosphor: peak wavelength 580 nm
Third phosphor: peak wavelength 640 nm
Table 4 shows the theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 13. As shown in Table 4, the theoretical limiting efficiency (lm / W) of the light emitting device of Example 13 is 255 (lm / W), the average color rendering index (Ra) is 88, and the special color rendering index (R9). ) Is 75.

  Table 4 shows the ratio of the light intensity of each peak wavelength of the first phosphor, the second phosphor, and the third phosphor to the light intensity (1.00) of the peak wavelength of the light emitting element 102. As shown in Table 4, the intensity of light at the peak wavelength of the first phosphor is 0.54 with respect to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 0.72, and the intensity of light having a peak wavelength of the third phosphor is 0.64.

  Further, when the spectrum of the light emitted from the light emitting device of Example 13 was examined, the spectrum of the light emitted from the light emitting device of Example 13 showed that the light emitting element 102, the first phosphor, the second phosphor, and Since the peak wavelength of each light emitted from the third phosphor appears, the light emitting device of Example 13 has the emission color from the light emitting element 102, the emission color from the first phosphor, and the second. It can be seen that light of a mixed color of the emission color from the phosphor and the emission color from the third phosphor is emitted.

  The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 65 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Is 60 nm, and the standard deviation of the absolute value of these differences is 15 nm or less. Therefore, the peak wavelength of light emitted from the first phosphor, the second phosphor, and the third phosphor is approximately It is arranged at equal intervals.

(Example 14)
The particle diameter and / or composition of the core of the semiconductor nanoparticles in Example 11 is appropriately changed, and light having the following peak wavelengths is emitted by irradiating light from the light emitting element 102 in Example 11. The light-emitting device of Example 14 having the same configuration as that of Example 11 is manufactured except that the phosphor 105 including the phosphor, the second phosphor, the third phosphor, and the fourth phosphor is used.
First phosphor: peak wavelength 500 nm
Second phosphor: peak wavelength 540 nm
Third phosphor: peak wavelength 580 nm
Fourth phosphor: peak wavelength 630 nm
Table 4 shows the theoretical limit efficiency (lm / W), average color rendering index (Ra), and special color rendering index (R9) of the light emitting device of Example 14. As shown in Table 4, the theoretical limit efficiency (lm / W) of the light emitting device of Example 14 is 265 (lm / W), the average color rendering index (Ra) is 91, and the special color rendering index (R9). ) Is 80.

  Table 4 shows the light intensity of each of the first phosphor, the second phosphor, the third phosphor, and the fourth phosphor with respect to the light intensity (1.00) of the peak wavelength of the light emitting element 102. The ratio of As shown in Table 4, the intensity of light at the peak wavelength of the first phosphor is 0.38 relative to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 0.45, the intensity of light having a peak wavelength of the third phosphor is 0.51, and the intensity of light having a peak wavelength of the fourth phosphor is 0.64.

  Further, when the spectrum of the light emitted from the light emitting device of Example 14 was examined, the spectrum of the light emitted from the light emitting device of Example 14 includes the light emitting element 102, the first phosphor, the second phosphor, Since the peak wavelength of each light emitted from the third phosphor and the fourth phosphor appears, the light-emitting device of Example 14 has the emission color from the light-emitting element 102 and the light emission from the first phosphor. It can be seen that light of a mixed color of the color, the emission color from the second phosphor, the emission color from the third phosphor, and the emission color from the fourth phosphor is emitted.

  The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 40 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. The absolute value of the difference between the peak wavelength of the adjacent third phosphor and the peak wavelength of the fourth phosphor is 50 nm, and the standard deviation of the absolute value of these differences is 15 nm or less. Therefore, the peak wavelengths of the light emitted from the first phosphor, the second phosphor, the third phosphor, and the fourth phosphor are arranged at substantially equal intervals.

(Example 15)
The particle diameter and / or composition of the core of the semiconductor nanoparticles in Example 11 is appropriately changed, and light having the following peak wavelengths is emitted by irradiating light from the light emitting element 102 in Example 11. The light emitting device of Example 15 having the same configuration as that of Example 11 is manufactured except that the phosphor 105 composed of the phosphor, the second phosphor, the third phosphor, and the fourth phosphor is used.
First phosphor: peak wavelength 510 nm
Second phosphor: peak wavelength 550 nm
Third phosphor: peak wavelength 600 nm
Fourth phosphor: peak wavelength 650 nm
Table 4 shows the theoretical limit efficiency (lm / W), the average color rendering index (Ra), and the special color rendering index (R9) of the light emitting device of Example 15. As shown in Table 4, the theoretical limiting efficiency (lm / W) of the light emitting device of Example 15 is 245 (lm / W), the average color rendering index (Ra) is 88, and the special color rendering index (R9). ) Is 92.

  Table 4 shows the light intensity of each of the first phosphor, the second phosphor, the third phosphor, and the fourth phosphor with respect to the light intensity (1.00) of the peak wavelength of the light emitting element 102. The ratio of As shown in Table 4, the intensity of light at the peak wavelength of the first phosphor is 0.57 with respect to the intensity of light at the peak wavelength of the light emitting element 102 (1.00), and the peak of the second phosphor The intensity of light having a wavelength is 0.48, the intensity of light having a peak wavelength of the third phosphor is 0.57, and the intensity of light having a peak wavelength of the fourth phosphor is 0.52.

  Further, when the spectrum of the light emitted from the light emitting device of Example 15 was examined, the spectrum of the light emitted from the light emitting device of Example 15 includes the light emitting element 102, the first phosphor, the second phosphor, Since the peak wavelengths of the respective lights emitted from the third phosphor and the fourth phosphor appear, the light emitting device of Example 15 has the light emission color from the light emitting element 102 and the light emission from the first phosphor. It can be seen that light of a mixed color of the color, the emission color from the second phosphor, the emission color from the third phosphor, and the emission color from the fourth phosphor is emitted.

  The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 40 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. The absolute value of the difference between the peak wavelength of the adjacent third phosphor and the peak wavelength of the fourth phosphor is 50 nm, and the standard deviation of the absolute value of these differences is 15 nm or less. Therefore, the peak wavelengths of the light emitted from the first phosphor, the second phosphor, the third phosphor, and the fourth phosphor are arranged at substantially equal intervals.

  As shown in Table 4, by appropriately selecting a peak wavelength in the range of 560 nm to 610 nm and a peak wavelength in the range of 610 nm to less than 650 nm, the theoretical limit efficiency (lm / W) of the light emitting device and the average color rendering index It can be seen that (Ra) and the special color rendering index (R9) can be adjusted as appropriate.

  For example, if the special color rendering index (R9) is 25 as in the light emitting device of Example 11, the theoretical limit efficiency (lm / W) can be 280 (lm / W), and the light emitting device of Example 15 Thus, if the theoretical limit efficiency (lm / W) is 245 (lm / W), the special color rendering index (R9) can be 92.

  In the light emitting devices of Examples 11 to 15, even when the special color rendering index (R9) is increased and the theoretical limit efficiency is slightly sacrificed, the theoretical limit efficiency is shown as a conventional example in the background art section. It is possible to obtain a value higher than that of a configuration in which a light emitting element emitting blue light having a peak wavelength of 460 nm and a yellow phosphor are combined. In any of the configurations of the light emitting devices of Examples 11 to 15, the average color rendering index (Ra) is 85 or more, and the conventional light emitting element that emits blue light having a peak wavelength of 460 nm is combined with the yellow phosphor. A higher value than that of the other configuration can be obtained. Therefore, it can be seen that the light emitting devices of Examples 11 to 15 are excellent in both theoretical limit efficiency and color rendering as compared with the conventional example.

  In Tables 1 to 4, the numerical values in the upper column of “Peak wavelength (nm) and light intensity ratio of peak wavelength” are the respective peak wavelengths (nm) of light emitted from the light emitting element and the phosphor. The numerical value in the lower part shows the ratio of the light intensity at each peak wavelength of the phosphor to the light intensity (1.00) at the peak wavelength of the light emitting element.

(Example 16)
In FIG. 1, the typical side view of the light-emitting device of Example 16 of this invention is shown. Here, the light-emitting device of Example 16 is a light-emitting element composed of a light-emitting diode (LED) that emits light having a peak wavelength of 460 nm mounted with a silver paste inside a concave cup 101 provided at one end of a lead frame 100. 102 and a core of semiconductor nanoparticles (ZnSe) having a peak wavelength of 500 nm and a particle diameter of 9 nm dispersed in a light-transmitting resin 103 made of a light-transmitting silicone resin, and a layer thickness of 1 μm formed around the core. A first phosphor made of clad (ZnS), a core of semiconductor nanoparticles (Zn _0.62 Cd _0.38 Se) having a peak wavelength of 540 nm and a particle diameter of 6.5 nm, and a layer thickness of 1 μm formed around the core A second phosphor made of clad (ZnS) and semiconductor nanoparticles having a peak wavelength of 580 nm and a particle diameter of 9 nm (Zn _0.62 Cd _0.38 A third phosphor composed of a core (Se) and a clad (ZnS) having a layer thickness of 1 μm and a core of semiconductor nanoparticles (Zn _0.9 Cd _0.1 Se) having a peak wavelength of 630 nm and a particle diameter of 8 nm. And a phosphor 105 made of a fourth phosphor made of clad (ZnS) having a layer thickness of 1 μm formed around it.

As the light emitting element 102, for example, a GaN buffer layer having a layer thickness of 4 μm, an n-type Al _0.1 Ga _0.9 N lower cladding layer having a layer thickness of 1 μm, and a non-doped In _0.34 Ga _0.66 N having a layer thickness of 0.02 μm on the GaN substrate. An active layer, a thin Al _0.15 Ga _0.85 N evaporation prevention layer, a 1 μm thick p-type Al _0.1 Ga _0.9 N upper cladding layer, and a 1 μm thick p-type GaN cap layer are sequentially laminated, and the top surface and It is possible to use a GaN buffer layer having an electrode formed on the surface of the GaN buffer layer exposed by removing a part of the GaN substrate.

  The pair of lead frames 100 is provided with a power supply unit (not shown), and these lead frames 100 are electrically connected to the light emitting element 102 by wires 106 made of, for example, gold wires. Further, in order to seal these members, there is a light-transmitting resin 104 made of a shell-shaped light-transmitting silicone resin having a lens function capable of efficiently taking out light emitted from the phosphor 105 to the outside. Is provided.

  FIG. 8 shows a spectrum of light emitted from the light emitting device of Example 16 described above. As shown in FIG. 8, the spectrum of light emitted from the light emitting device of Example 16 is emitted from the light emitting element 102, the first phosphor, the second phosphor, the third phosphor, and the fourth phosphor. The peak wavelength of each light appears. Therefore, the light emitting device of Example 16 has the light emission color from the light emitting element 102, the light emission color from the first phosphor, the light emission color from the second phosphor, the light emission color from the third phosphor, It can be seen that light of a mixed color of the luminescent color from the four phosphors is emitted. The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 40 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Since the absolute value of the difference between the peak wavelength of the third phosphor and the peak wavelength of the fourth phosphor is 50 nm, the standard deviation of the absolute value of these differences is 15 nm. The peak wavelengths of light emitted from the first phosphor, the second phosphor, the third phosphor, and the fourth phosphor are arranged at substantially equal intervals.

  The light-emitting device of Example 16 having such a configuration may have a theoretical marginal efficiency of 265 (lm / W) as very good as the average color rendering index (Ra) as 91. it can. In the light emitting device of Example 16, a very high color rendering index (R9) of 92 is obtained. These values are higher than those obtained by combining a light-emitting element that emits blue light having a peak wavelength of 460 nm and a yellow phosphor shown in the conventional example.

  9 shows the light-emitting device of Example 16 (phosphor peak wavelengths: 460 nm, 500 nm, 540 nm, 580 nm, 630 nm), red phosphor (peak wavelength: 630 nm), and green phosphor (peak wavelength: 540 nm). And a conventional light emitting device including a blue phosphor (peak wavelength: 460 nm), each phosphor is mixed so that white (x = 0.3, y = 0.3) is obtained in the CIE chromaticity diagram. FIG. 6 is a diagram in which an influence on white, which is a luminescent color, is estimated when the amount of mixture of phosphors of one color varies. In FIG. 9, white squares and black rhombuses indicate that the amount of green phosphor (peak wavelength: 540 nm) is decreased, and white circles and black triangles indicate that the amount of red phosphor (peak wavelength: 630 nm) is decreased. Each case is shown.

  As shown in FIG. 9, in the light emitting device of Example 16, it is possible to reduce the deviation of the emission color with respect to the change in the phosphor mixing amount, and to suppress the emission color variation caused by the manufacturing variation. There is also.

(Example 17)
FIG. 10 shows a schematic perspective view of the light emitting device of Example 17 of the present invention. A light emitting element 1002 made of a GaN-based light emitting diode of 5 mm square that emits light having a peak wavelength of 460 nm as in Example 16 is placed inside the concave recess of the ceramic material 1001 having a concave recess and a thickness of about 5 mm. It is mounted with silver paste. A wire 1004 made of, for example, a gold wire is provided so as to be electrically connected from an electrode pad portion (not shown) of the light emitting element 1002 to a power supply terminal 1000 provided on the outer surface of the ceramic material 1001. The power is supplied from a power supply unit (not shown) through the power supply terminal 1000. Further, as in the case of Example 16, the light emitting element 1002 is a light in which four phosphors 1005 (first phosphor, second phosphor, third phosphor, and fourth phosphor) having different peak wavelengths are dispersed. It is covered with a light transmissive resin 1003 made of a transmissive silicone resin.

  Further, when the spectrum of light emitted from the light emitting device of Example 17 was examined, each light emitted from the light emitting element 1002, the first phosphor, the second phosphor, the third phosphor, and the fourth phosphor. The peak wavelength is shown. Therefore, the light-emitting device of Example 17 includes the emission color from the light-emitting element 1002, the emission color from the first phosphor, the emission color from the second phosphor, the emission color from the third phosphor, It can be seen that light of a mixed color of the luminescent color from the four phosphors is emitted.

  The light-emitting device of Example 17 having such a configuration can be thinned because it has good luminous efficiency and heat generation due to Stokes loss can be reduced. Also, the color rendering properties of the light emitting device of Example 17 can be very good.

  In the light emitting device of Example 17, an optical film that reflects the light emitted from the light emitting element 1002 and / or the light emitted from the phosphor, in the concave depression of the ceramic material 1001, for example, A metal film made of aluminum may be formed.

(Example 18)
FIG. 11 shows a schematic perspective view of the light emitting device of Example 18 of the present invention. The back surface side of the light-transmitting resin plate 1101 made of acrylic resin is the surface side of the light-transmitting resin plate 1101 that transmits light from the light-emitting element 1104 propagating through the light-transmitting resin plate 1101 (in the direction of the arrow shown in FIG. 11). It is shaped to radiate to On the back surface of the light transmissive resin plate 1101, a diffusion portion 1103 in which polymer particles that diffuse light propagating through the light transmissive resin plate 1101 into uniform light is provided. In addition, an aluminum metal film 1100 is formed on the back surface of the diffusion portion 1103.

  Further, on the surface of the light-transmitting resin plate 1101, a light-transmitting resin 1102 made of a light-transmitting silicone resin in which a phosphor (not shown) having the same configuration as that of Example 16 is dispersed is installed. ing.

  The light-emitting element 1104 is a GaN-based light-emitting diode similar to that in Example 16 that emits light having a peak wavelength of 460 nm, and a plurality of the light-emitting elements 1104 are arranged on one end surface side of the light-transmitting resin plate 1101. Has been. In the light emitting device of Example 18, the light emitting element 1104 is not covered with the light transmissive resin.

  Further, an optical film having total reflection characteristics such that light propagating in the light transmissive resin plate 1101 is not emitted to the outside on each end surface of the light transmissive resin plate 1101 where the light emitting element 1104 is not disposed, for example, An aluminum metal film (not shown) is provided.

  Further, when the spectrum of the light emitted from the light emitting device of Example 18 was examined, each light emitted from the light emitting element 1104, the first phosphor, the second phosphor, the third phosphor, and the fourth phosphor. The peak wavelength is shown. Therefore, the light-emitting device of Example 18 has the emission color from the light-emitting element 1104, the emission color from the first phosphor, the emission color from the second phosphor, the emission color from the third phosphor, It can be seen that light of a mixed color of the luminescent color from the four phosphors is emitted.

  In the light-emitting device of Example 18 having the above configuration, light emitted from the light-emitting element 1104 is scattered in the light-transmitting resin plate 1101 to become uniform light, and the light-transmitting resin 1102 in which the phosphor is dispersed is applied. Irradiated and emitted from the phosphor, the light emission efficiency is good, and a flat light emitting device with very good color rendering can be obtained.

Example 19
FIG. 12 shows a schematic configuration diagram of a light emitting device of Example 19 of the present invention. The light emitting device of Example 19 includes a light emitting device 1200 made of a semiconductor laser that emits light having a peak wavelength of 440 nm, an aspheric lens 1201, and an S.A. made of a silica-based material having a core diameter of 1 mm. Light transmission made of a light transmissive silicone resin in which a light guide 1203 made of an I (step index) type optical fiber and three types of phosphors (not shown) emitting light having different peak wavelengths are dispersed. Resin 1204. Here, the light emitting element 1200, the aspheric lens 1201, and one end surface of the light guide 1203 are housed in one module 1202 portion.

Further, as a semiconductor laser constituting the light emitting device 1200, for example, an n-type GaN buffer layer, an n-type Al _0.1 Ga _0.9 N layer having a layer thickness of 0.95 μm, and an n-type GaN guide layer having a layer thickness of 100 nm are formed on a GaN substrate. , In _v Ga _1-v N (0 ≦ v ≦ 1) barrier layer and In _w Ga _1-w N (0 ≦ w ≦ 1) well layer, each of which is a multiple quantum well active layer having a layer thickness of 18 nm A p-type Al _0.2 Ga _0.8 N evaporation prevention layer, a p-type GaN optical guide layer with a thickness of 100 nm, a p-type Al _0.1 Ga _0.9 N cladding layer with a thickness of 0.5 μm, and a p-type GaN contact layer with a thickness of 0.1 μm A 10 μm-wide broad-area element structure or the like in which electrodes are formed on the surface of the n-type Al _0.1 Ga _0.9 N layer and the surface of the p-type GaN contact layer, respectively, is used. Here, the composition ratio and film thickness of InGaN constituting the multiple quantum well active layer are set so as to emit light having a peak wavelength of 440 nm.

Further, as the phosphor, a first phosphor comprising a core of semiconductor nanoparticles (ZnSe) having a peak wavelength of 510 nm and a particle diameter of 10 nm and a clad (ZnS) having a layer thickness of 1 μm formed therearound, a peak A second phosphor comprising a core of semiconductor nanoparticles (Zn _0.62 Cd _0.38 Se) having a wavelength of 570 nm and a particle diameter of 8 nm and a clad (ZnS) having a layer thickness of 1 μm formed around the core, and a peak wavelength of 630 nm A third phosphor composed of a core of semiconductor nanoparticles (Zn _0.9 Cd _0.1 Se) having a particle diameter of 7 nm and a clad (ZnS) having a thickness of 1 μm formed around the core is used. The full width at half maximum of each peak of light emitted from these phosphors is 30 nm or more and 40 nm or less.

  Light emitted from the light emitting element 1200 is introduced into the light guide 1203 from one end surface of the light guide 1203 via the aspheric lens 1201, propagates through the light guide 1203, and then the other end of the light guide 1203. The light emitted from the light emitting element 1200 is irradiated with each of the three types of phosphors dispersed in the light transmitting resin 1204 provided at the other end of the light guide 1203. And light from the three types of phosphors are emitted.

  FIG. 13 shows a spectrum of light emitted from the light emitting device of Example 19 described above. As shown in FIG. 13, the spectrum of the light emitted from the light emitting device of Example 19 shows the peak of each light emitted from the light emitting element 1200, the first phosphor, the second phosphor, and the third phosphor. Wavelength appears. Therefore, the light-emitting device of Example 19 includes the emission color from the light-emitting element 1200, the emission color from the first phosphor, the emission color from the second phosphor, the emission color from the third phosphor, It can be seen that light of a mixed color of the luminescent color from the four phosphors is emitted. The absolute value of the difference between the peak wavelength of the adjacent first phosphor and the peak wavelength of the second phosphor is 60 nm, and the difference between the peak wavelength of the adjacent second phosphor and the peak wavelength of the third phosphor. Since the absolute value of the difference is 60 nm, the standard deviation of the absolute value of these differences is 15 nm or less, and the peak wavelengths of the light emitted from the first phosphor, the second phosphor, and the third phosphor are substantially equal. It can be seen that they are arranged at intervals.

  By limiting the peak wavelengths of the light emitted from the light emitting element 1200 and the light emitted from the phosphor to 440 nm, 510 nm, 570 nm, and 630 nm, respectively, while maintaining the color rendering property (Ra) as good as 85, the theoretical limit efficiency Can be as good as 257 (lm / W). Furthermore, a special color rendering index (R9) indicating the appearance of a red object can be as high as 65. These values are higher than those obtained by combining a light-emitting element that emits blue light having a peak wavelength of 460 nm and a yellow phosphor shown in the conventional example.

  With the configuration as described above, in the light-emitting device of Example 19, a light-emitting element made of a semiconductor laser that can be easily optically coupled to a light-guide made of an optical fiber is used. Since the light from the light emitting element is collected in the part, the fluorescent light with high luminance can be obtained. In the light emitting device of Example 19, the heat energy loss due to the Stokes loss generated in the phosphor can be reduced, so that the configuration with high luminance can be achieved. Furthermore, a phosphor in which a transition metal is dispersed in an oxide or sulfide has a relatively long emission lifetime on the order of several microseconds to milliseconds. On the other hand, the phosphor containing semiconductor nanoparticles used in the light emitting device of Example 19 has a very fast emission lifetime of several nanoseconds, and quickly emits light with a high light density applied to the phosphor. Luminance saturation is unlikely to occur because light can be emitted. Therefore, it is preferable to use a phosphor containing semiconductor nanoparticles.

(Example 20)
In FIG. 14, the typical perspective view of the light-emitting device of Example 20 of this invention is shown. A light emitting element 1403 made of a semiconductor laser that emits light having a peak wavelength of 440 nm as in Example 19 is mounted with a silver paste in a concave recess of a ceramic material 1401 having a thickness of about 5 mm having a concave recess. ing. A gold wire 1404 is provided so as to be electrically connected from an electrode pad portion (not shown) of the light emitting element 1403 to a power supply terminal 1400 provided on the outer surface of the ceramic material 1401. Power is supplied from the power supply unit (not shown) to the light emitting element 1403 via the power supply terminal 1400. Further, three types of phosphors (first phosphor, second phosphor, and third phosphor) having the same configuration as in Example 16 having different peak wavelengths at the positions irradiated with the light emitted from the light emitting element 1403 A light transmissive resin 1402 made of a light transmissive silicone resin in which is dispersed) is provided.

  Further, when the spectrum of the light emitted from the light emitting device of Example 20 was examined, the peak wavelengths of the light emitted from the light emitting element 1403, the first phosphor, the second phosphor, and the third phosphor appeared. ing. Therefore, the light emitting device of Example 20 includes the light emission color from the light emitting element 1403, the light emission color from the first phosphor, the light emission color from the second phosphor, and the light emission color from the third phosphor. It can be seen that mixed color light is emitted.

  The light emitting device of Example 20 having such a configuration can be thin, have good light emission efficiency with respect to input power, and have very good color rendering.

  In addition, since the light emitting device of Example 20 can suppress heat generation due to Stokes loss in the phosphor, the light irradiation region from the light emitting element 1403 can be narrowed down. Therefore, since the light-transmitting resin 1402 in which the phosphor is dispersed can be reduced, the configuration is suitable for downsizing of the light-emitting device.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  According to the present invention, it is possible to provide a light emitting device that has both excellent luminous efficiency and color rendering properties (average color rendering index (Ra) and special color rendering index (R9)).

It is a typical side view of an example of the light-emitting device of this invention. It is a figure which shows the spectrum of the light light-emitted from the light-emitting device of Example 1 of this invention. It is a figure which shows a 2 degree visual field color matching function which is a correlation with the sensitivity which the human eye perceives the light of the wavelength and the light of the wavelength as red, green, and blue. It is a figure which shows the spectrum of the light light-emitted from the light-emitting device of Example 5 of this invention. It is a figure which shows the spectrum of the light light-emitted from the light-emitting device of Example 7 of this invention. It is a figure which shows the spectrum of the light light-emitted from the light-emitting device of Example 8 of this invention. It is a figure which shows the spectrum of the light light-emitted from the light-emitting device of Example 11 of this invention. It is a figure which shows the spectrum of the light light-emitted from the light-emitting device of Example 16 of this invention. It is the figure which estimated the influence with respect to white which is a luminescent color, when the mixing amount of the fluorescent substance of one color is fluctuate | varied regarding the light-emitting device of Example 16 of this invention, and the conventional light-emitting device. It is a typical perspective view of the light-emitting device of Example 17 of this invention. It is a typical perspective view of the light-emitting device of Example 18 of this invention. It is a typical block diagram of the light-emitting device of Example 19 of this invention. It is a figure which shows the spectrum of the light light-emitted from the light-emitting device of Example 19 of this invention. It is a typical perspective view of the light-emitting device of Example 20 of this invention.

Explanation of symbols

  101 Cup, 102, 1002, 1104, 1200, 1403 Light emitting element, 103, 104, 1003, 1102, 1204, 1402 Light transmitting resin, 105, 1005 Phosphor, 106, 1004, 1404 Wire, 1000, 1400 Power supply terminal , 1001, 1401 ceramic material, 1100 aluminium metal film, 1101 light transmitting resin plate, 1103 diffusion portion, 1201 aspherical lens, 1202 module, 1203 light guide.

Claims (11)

  A light emitting element that emits light having a peak wavelength of 440 nm or more and less than 480 nm, and three or more phosphors that emit light having a peak wavelength different from that of the light emitting element by irradiating light from the light emitting element. A light emitting device that emits light of a mixed color of a light emission color from the light emitting element and a light emission color of the phosphor.   The light emitting device according to claim 1, wherein the light emitting element is a light emitting diode or a semiconductor laser including at least a nitride semiconductor.   3. The light emitting device according to claim 1, wherein all of the peak wavelengths of light emitted from the phosphor are in a range of 490 nm to less than 760 nm.   The light emitting device according to claim 3, wherein peak wavelengths of light emitted from the phosphor are arranged at substantially equal intervals.   At least one of the peak wavelengths of light emitted from the phosphor is in the range of 490 nm to less than 560 nm, at least one is in the range of 560 nm to less than 610 nm, and at least one is in the range of 610 nm to less than 650 nm. The light-emitting device according to claim 3, wherein the light-emitting device is provided.   The light emitting device according to claim 1, wherein the phosphor includes a mixed crystal of semiconductor, and a peak wavelength of light emitted from the phosphor can be controlled by a mixed crystal ratio of the semiconductor.   The light emitting device according to claim 1, wherein the phosphor includes semiconductor nanoparticles, and a peak wavelength of light emitted from the phosphor can be controlled by a particle diameter of the nanoparticles.   A lead frame on which the light emitting element is installed; a power supply unit provided on the lead frame; a wire for electrically connecting the light emitting element; and a light transmissive resin in which the phosphor is dispersed. The light-emitting device according to claim 1, wherein the light-emitting device is a light-emitting device.   The light-emitting device according to claim 8, wherein the light-emitting element is installed in the light-transmitting resin.   Light that has propagated through the light guide, comprising: a light guide for propagating light emitted from the light emitting element; and a light transmissive resin in which the phosphor is dispersed at one end of the light guide. The light emitting device according to claim 1, wherein the phosphor is irradiated from one end of the light guide.   The light-emitting device according to claim 10, wherein the light guide is an optical fiber.

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