JP6082833B1 - Light emitting device and image display device - Google Patents

Abstract

A light emitting device capable of realizing an image display device having a wide color reproduction range is provided. A light emitting device (10) includes a light emitting element (11) that emits blue light, a Mn2 + activated γ-AlON phosphor that is a green phosphor (13), and a Mn4 + activated fluorescence that is a red phosphor (12). With body. The concentration of Mn contained in the Mn2 + activated γ-AlON phosphor is 1.5 wt% or more and 4.5 wt% or less. [Selection] Figure 1

Description

  The present invention relates to a light emitting device including a light emitting element and a wavelength conversion member, and an image display device including the light emitting device.

  In recent years, (i) a light emitting element such as a light emitting diode (LED), and (ii) a wavelength conversion member that converts excitation light from the light emitting element into fluorescence (for example, phosphor particles are dispersed in a resin) And a light emitting device in combination with a member has been developed. The light emitting device is advantageous in that it is small in size and consumes less power than an incandescent bulb. Therefore, the light-emitting device has been put into practical use as a light source for various image display devices or illumination devices.

  As such a light emitting device, a combination of a blue LED and a yellow phosphor is generally used. As the yellow phosphor, Ce-activated YAG (yttrium aluminum garnet) phosphor is widely used because of its high luminous efficiency.

  By the way, when the light emitting device is used as an image display device, the color reproduction range of the image display device is expanded as the half-value width of the emission spectrum of the phosphor is narrowed. However, the half-value width of the emission spectrum of the Ce-activated YAG phosphor is relatively wide at about 100 nm. For this reason, when a light-emitting device using a Ce-activated YAG phosphor as a yellow phosphor is used as a liquid crystal backlight of an image display device, the color reproduction range is not wide enough.

  Specifically, the image display device described above can cover almost the entire area of the sRGB color gamut, which is the color gamut used for CRT (Cathode Ray Tube). However, the coverage is not limited to the NTSC color gamut or AdobeRGB color gamut defined by the NTSC (National Television System Committee), which is a color gamut wider than sRGB and used for a wide color gamut liquid crystal display. Is significantly lower.

  More specifically, the color gamut of an image display device using a light emitting device using a Ce-activated YAG yellow phosphor as a liquid crystal backlight is only about 70% of the NTSC and AdobeRGB color gamuts. . Therefore, the light emitting device is not suitable for use in a wide color gamut liquid crystal display.

  Here, the color gamut of sRGB is (CIEx, CIEy) = (0.640, 0.330), (0.300, 0.600) on CIE (Commission Internationale de l'Eclairage) 1931 chromaticity coordinates. ), (0.150, 0.060) is a color gamut defined by a triangle surrounded by three chromaticity points.

  On the other hand, the NTSC color gamut refers to (CIEx, CIEy) = (0.670, 0.330), (0.210, 0.710), (0.140, 0.080) on the CIE1931 chromaticity coordinates. ) Is a color gamut defined by a triangle surrounded by three chromaticity points. Further, the color gamut of AdobeRGB is (CIEx, CIEy) = (0.640, 0.330), (0.210, 0.710), (0.150, 0.060) on the CIE1931 chromaticity coordinates. ) Is a color gamut defined by a triangle surrounded by three chromaticity points. When comparing the color gamut of sRGB with the color gamut of NTSC or AdobeRGB, the color gamut of NTSC and AdobeRGB has a wider color gamut.

  As a light emitting device used as a backlight of a wide color gamut liquid crystal display corresponding to NTSC or AdobeRGB, a configuration using a combination of two color phosphors of a green phosphor and a red phosphor is suitable. Furthermore, it is preferable that the half width of the emission spectrum of these phosphors is narrow.

For example, Patent Document 1 discloses a light-emitting device using a combination of an Eu-activated βSiAlON phosphor (green phosphor) and a Mn ^{4 +} -activated fluoride complex (red phosphor) as a phosphor. According to this combination, it is possible to realize a wide color gamut when an image display device is configured, compared to a configuration in which a yellow phosphor is used as a phosphor, which has been generally used conventionally. This is due to the fact that the half width of the emission spectrum of the Eu-activated βSiAlON phosphor and the half width of the Mn ⁴⁺ activated fluorine complex phosphor are both narrower than those of the Ce-activated YAG phosphor. Specifically, the half-value width of the emission spectrum of the Eu-activated βSiAlON phosphor is 55 nm or less. Moreover, the half value width of Mn4 ⁺ activation fluorine complex fluorescent substance is 10 nm or less.

Further, as a configuration capable of realizing a wider color gamut than the light emitting device of Patent Document 1, for example, Patent Document 2 discloses that as a phosphor, Mn-activated γ-AlON phosphor (green phosphor) and Mn ^{4 +} -activated fluoride complex. A light emitting device using a combination of (red phosphor) is disclosed. Patent Document 2 discloses that the peak wavelength of the emission spectrum of the green phosphor is 510 nm to 550 nm, and the half width of the emission spectrum is 55 nm or less (preferably 45 nm or less). As an example of producing a green phosphor, a Mn-activated γ-AlON phosphor having a peak wavelength of 515 nm and a half width of 33 nm is mentioned.

  Furthermore, Patent Document 3 discloses a light emitting device using a Mn-activated oxide phosphor or a Mn-activated oxynitride phosphor as a green phosphor. Specifically, a light emitting device using a combination of the green phosphor and the Eu activated phosphor (red phosphor) as a phosphor is disclosed. It is disclosed that the half-value width of the emission spectrum of the green phosphor is 40 nm or less. Similarly to Patent Document 2, as an example of producing a green phosphor, a Mn-activated γ-AlON phosphor having a peak wavelength of 515 nm and a half width of 33 nm is cited.

  Note that Patent Document 4 discloses a manufacturing example of a color filter used in an image display device.

WO2009 / 110285 (published on September 11, 2009) JP 2010-93132 A (released on April 22, 2010) JP 2009-218422 A (published September 24, 2009) Japanese Patent Laying-Open No. 2015-87527 (published on May 7, 2015)

However, in the configuration of Patent Document 1, Eu-activated βSiAlON phosphor is used as the green phosphor, and in the configuration of Patent Document 3, Eu-activated phosphor is used as the red phosphor. Therefore, it can be realized in comparison with a color gamut that can be realized by a light emitting device using a combination of Mn activated γ-AlON phosphor (green phosphor) and Mn ⁴⁺ activated fluoride complex (red phosphor) as a phosphor. The color gamut may be narrowed.

  In the configuration disclosed in Patent Document 2, an image display apparatus having a color gamut required for a wide color gamut liquid crystal display may not be realized. More specifically, the area ratio which is the ratio of the area of the color gamut of the image display device of Patent Document 2 to the area of the NTSC color gamut is large. However, the cover ratio, which is the ratio of the area covered by the color gamut of the image display device of Patent Document 2 to at least the area of the NTSC color gamut, is not high. Therefore, when the image display device of Patent Document 2 is used as an image display device compliant with a wide color gamut standard such as NTSC or Adobe RGB, the color gamut that can be substantially displayed may be narrowed. . That is, even in the configuration of Patent Document 2, it is difficult to realize an image display device with higher color reproducibility for a wide color gamut such as the NTSC color gamut or the AdobeRGB color gamut.

  Therefore, an object of the present invention is to provide a light emitting device that can realize an image display device having a wide color reproduction range, and an image display device including the light emitting device.

In order to solve the above-described problem, a light-emitting device according to one embodiment of the present invention includes a light-emitting element that emits blue light, the Mn ²⁺ -activated γ-AlON phosphor that emits green light when excited by the blue light, and Mn ⁴⁺ activated phosphor that emits red light when excited by blue light, and the concentration of Mn contained in the Mn ²⁺ activated γ-AlON phosphor is 1.5 wt% or more and 4.5 wt% or less. is there.

  According to one embodiment of the present invention, it is possible to provide a light-emitting device that can realize an image display device having a wide color reproduction range.

It is sectional drawing which shows the light-emitting device which concerns on Embodiment 1 of this invention. It is a graph which shows a human visibility curve. It is a graph which shows the emission spectrum and excitation spectrum of a green fluorescent substance, Comprising: (a) and (g) are the emission spectrum and excitation spectrum of the green fluorescent substance which concern on a comparative manufacture example, (b)-(f) and (h) These are the graphs which show the emission spectrum and excitation spectrum of the green fluorescent substance which concern on each manufacture example of Embodiment 1 of this invention. It is a table | surface which shows the mixing ratio and measurement result of the raw material powder of the green fluorescent substance which concern on the said comparative manufacture example and each manufacture example. It is a graph which shows the emission spectrum and excitation spectrum of the red fluorescent substance which concern on the manufacture example of Embodiment 1 of this invention. (A) is a graph which shows the emission spectrum of the green fluorescent substance which concerns on the said comparative manufacture example, and each manufacture example, and the excitation spectrum of the said red fluorescent substance, (b) is the green which concerns on the said comparative manufacture example and each manufacture example. It is a graph which shows the emission spectrum of fluorescent substance, and the emission spectrum of the said red fluorescent substance. (A) And (g) is a graph which shows the emission spectrum of the light-emitting device which concerns on a comparative example, (b)-(f) and (h) are graphs which show the emission spectrum of the light-emitting device which concerns on each Example. . In the light emitting devices of the examples and comparative examples, the mixing ratio of the green phosphor and the red phosphor dispersed in the dispersion material (resin) and the mixing ratio of the dispersion material, the green phosphor and the red phosphor are shown. It is a table. (A) is a disassembled perspective view of the image display apparatus which concerns on Embodiment 2 of this invention, (b) is a disassembled perspective view of the liquid crystal display device with which the image display apparatus shown by (a) is equipped. . It is a graph which shows the transmission spectrum of a color filter. It is a table | surface which shows the coverage, area ratio, and chromaticity coordinate of the image display apparatus of each Example which concerns on Embodiment 2 of this invention, and a comparative example. (A)-(h) is a graph which compares the color gamut of the image display apparatus of each Example or comparative example which concerns on Embodiment 2 of this invention, and the color gamut of NTSC and AdobeRGB. It is sectional drawing which shows the light-emitting device which concerns on Embodiment 3 of this invention. Embodiment 4 and Embodiment 6 of the present invention The mixing ratio of the green phosphor and the red phosphor dispersed in the dispersion material (resin) of the light emitting device according to Embodiment 6 and the dispersion material, the green phosphor, and the red phosphor It is a table | surface which shows a mixing ratio and luminous efficiency. (A) is a disassembled perspective view of the image display apparatus which concerns on Embodiment 5 of this invention, (b) is a disassembled perspective view of the liquid crystal display device with which the image display apparatus shown by (a) is equipped. . It is a graph which shows the transmission spectrum of a color filter. The mixing ratio of the green phosphor and the red phosphor dispersed in the dispersion material (resin) of the light emitting device of the example according to Embodiment 5 of the present invention, and the mixing of the dispersion material with the green phosphor and the red phosphor It is a table | surface which shows a ratio. It is a table | surface which shows the coverage, area ratio, and chromaticity coordinate of the image display apparatus of the Example which concerns on Embodiment 5 of this invention.

Hereinafter, embodiments of the present invention will be described in detail. The light-emitting devices 10 and 10a according to one embodiment of the present invention include a light-emitting element 11 that emits blue light, a green phosphor 13 that emits green light when excited by blue light, and a red that emits red light when excited by blue light. And a phosphor 12. In one embodiment of the present invention, a Mn ²⁺ activated γ-AlON phosphor is used as the green phosphor 13, and a Mn ⁴⁺ activated phosphor is used as the red phosphor 12. And the density | concentration of Mn contained in the crystal | crystallization of the said Mn2 ⁺ activated gamma-AlON fluorescent substance is 1.5 wt% or more and 4.5 wt% or less.

  As a result of diligent research, the inventors of the present invention can increase the coverage of the NTSC color gamut and Adobe RGB color gamut when the Mn concentration is 1.5 wt% or more in the phosphor combination. I found out that I can do it. Details will be described below.

Embodiment 1
Embodiment 1 of the present invention will be described below with reference to FIGS. In the present embodiment, a light-emitting device 10 that can be used as a backlight of an image display device and can realize an image display device with high emission efficiency and a wide color reproduction range will be described.

(Light-emitting device 10)
FIG. 1 is a cross-sectional view showing the light emitting device 10. As shown in FIG. 1, the light emitting device 10 includes a light emitting element 11, a red phosphor 12, a green phosphor 13, a printed wiring board 14, a resin frame 15, and a dispersion material 16.

(Light emitting element 11)
The light emitting element 11 is a light emitting element that emits blue light. As the light emitting element 11, primary light (excitation light) composed of blue light that is absorbed by the Mn ²⁺ activated γ-AlON phosphor that is the green phosphor 13 and the Mn ⁴⁺ activated phosphor that is the red phosphor 12 and generates fluorescence. If it emits, it will not specifically limit. As the light emitting element 11, for example, a gallium nitride (GaN) based semiconductor can be used.

  The peak wavelength of primary light (excitation light) emitted from the light emitting element 11 is preferably 420 nm or more and 480 nm or less, and more preferably 440 nm or more and 460 nm or less.

  When the peak wavelength of the primary light (excitation light) emitted from the light emitting element 11 is 420 nm or more and 480 nm or less, the red phosphor 12 and the green phosphor 13 have high excitation efficiency, and thus the light emitting element 11 has high emission efficiency. When the peak wavelength of the primary light (excitation wavelength) is not less than 440 nm and not more than 460 nm, the light emitting element 11 has particularly high luminous efficiency, and the excitation spectrum of the red phosphor 12 described later and the blue color filter 126b described later. Therefore, the light emission efficiency of the light emitting device 10 can be further improved.

(Red phosphor 12)
The red phosphor 12 is a wavelength conversion member that emits red light when excited by the blue light emitted from the light emitting element 11, and is a Mn ⁴⁺ activated phosphor.

The Mn ⁴⁺ activated phosphor can be appropriately selected from Mn ⁴⁺ activated fluorine complex phosphor, Mn ⁴⁺ activated oxide phosphor, Mn ⁴⁺ activated oxyfluoride phosphor, etc. Among them, Mn ⁴⁺ activated fluorine complex phosphor is preferable. . This is because the full width at half maximum of the emission spectrum of red light emitted from the Mn ⁴⁺ activated fluorine complex phosphor is as narrow as 10 nm or less, and is excellent in color reproducibility in the red region. In addition, the Mn ⁴⁺ activated fluorine complex phosphor has high excitation efficiency for blue light.

As the Mn ⁴⁺ activated fluorine complex phosphor used as the red phosphor 12, for example, a phosphor represented by the following general formula (A) or general formula (B) can be used. As described above, the Mn ⁴⁺ activated fluorine complex phosphor has a very narrow half-width of the emission spectrum of 10 nm or less as described above, regardless of whether it is represented by the general formula (A) or the general formula (B). This is due to the nature of Mn ⁴⁺ which is a luminescent ion.

Formula _{(A): MI 2 (MII} 1-h Mn h) F 6
In the general formula (A), MI is at least one alkali metal element selected from the group consisting of Li, Na, K, Rb, and Cs. MII is at least one tetravalent metal element selected from the group consisting of Ge, Si, Sn, Ti and Zr. Moreover, it is preferable that it is 0.001 <= h <= 0.1.

  In general formula (A), MI is preferably K because of high emission intensity and high stability of the phosphor crystal. For the same reason, MII preferably contains Ti or Si.

In the general formula (A), the value of h represents the composition ratio (concentration) of Mn, that is, the concentration of Mn ⁴⁺ . When the value of h is less than 0.001, there is a problem that the concentration of Mn ⁴⁺ which is a luminescent ion is insufficient and sufficient brightness cannot be obtained. On the other hand, when the value of h exceeds 0.1, there is a problem that the brightness is greatly reduced due to concentration quenching or the like.

That is, the Mn ⁴⁺ activated fluorine complex phosphor represented by the general formula (A) is K ₂ (Ti _1-h Mn _h ) F ₆ or K ₂ (Si _1-h Mn _h ) F ₆ , where h is It is preferable that it is 0.001 or more and 0.1 or less.

Formula (B): MIII (MII _1-h Mn _h ) F ₆
In the general formula (B), MIII is at least one alkaline earth metal element selected from the group consisting of Mg, Ca, Sr, and Ba. MII is at least one tetravalent metal element selected from the group consisting of Ge, Si, Sn, Ti and Zr. Moreover, it is preferable that it is 0.001 <= h <= 0.1.

  In the general formula (B), it is preferable that MIII contains at least Ba because the phosphor has high luminous efficiency and is hardly deteriorated by heat and external force. For the same reason, MII preferably contains Ti or Si.

In particular, even if the Mn ⁴⁺ activated fluorine complex phosphor is represented by any of the general formulas (A) and (B), if MII is Si, the solubility of the phosphor in water is low, and fluorescence Since the water resistance of a body becomes high, it is more preferable. In the general formula (B), the value of h indicating the composition ratio (concentration) of Mn is preferably 0.001 ≦ h ≦ 0.1, similar to h in the general formula (A) described above.

(Green phosphor 13)
The green phosphor 13 is a wavelength conversion member that emits green light when excited by the blue light emitted from the light emitting element 11, and is a Mn ²⁺ activated γ-AlON phosphor.

The Mn ²⁺ activated γ-AlON used as the green phosphor 13 in the present embodiment has a composition formula M _a A _b Al _c O _d N _e (M is Mn, Ce, Pr, Nd, Sm, Eu, GD, Tb, Dy, Tm, and Yb are one or more metal elements including at least Mn, and A is one or more metal elements other than M and Al, where a + b + c + d + e = 1. As the Mn ²⁺ activated γ-AlON, those showing a composition in a range selected from values satisfying all the following conditions (1) to (5) are preferably used.

0.00001 ≦ a ≦ 0.1 (1)
0 ≦ b ≦ 0.40 (2)
0.10 ≦ c ≦ 0.48 (3)
0.25 ≦ d ≦ 0.60 (4)
0.02 ≦ e ≦ 0.35 (5).

The Mn ²⁺ activated γ-AlON phosphor used as the green phosphor 13 has a green light emission spectrum having a peak wavelength of 518 nm or more (preferably 520 nm or more) and 528 nm or less. In other words, the half width of the emission spectrum of the green light is 35 nm to 50 nm (preferably 45 nm or less) in the Mn ²⁺ activated γ-AlON phosphor used as the green phosphor 13.

In order to set the peak wavelength of the emission spectrum of green light emitted from the Mn ²⁺ activated γ-AlON phosphor to 518 nm to 528 nm and the half width to 35 nm to 50 nm, for example, the design composition of the Mn ²⁺ activated γ-AlON phosphor or This can be realized by appropriately controlling manufacturing conditions such as firing conditions.

In addition, the peak wavelength and the half-value width in the above range are 1.5 wt% (wt%) or more and 4.5 wt% or less (preferably 3. wt%) of Mn incorporated into the crystal of the Mn ²⁺ activated γ-AlON phosphor. 1 wt% or less). Even when the Mn concentration is at least 1.5% by weight or more, for example, the design conditions of the Mn ²⁺ activated γ-AlON phosphor or the production conditions such as the firing conditions are appropriately controlled. That is, the concentration of Mn contained in the Mn ²⁺ activated γ-AlON phosphor used as the green phosphor 13 (ie, the Mn ²⁺ incorporated in the crystal of the Mn ²⁺ activated γ-AlON phosphor as the final product). It can be said that (concentration) is 1.5 wt% or more and 4.5 wt% or less.

As described above, in the light emitting device 10, the emission spectrum of the Mn ²⁺ activated γ-AlON phosphor, which is the green phosphor 13 used as the wavelength conversion member, is appropriately controlled as described above. Therefore, by providing the light emitting device 10 in the image display device, it is possible to realize an image display device having a high coverage for a wide color gamut such as the NTSC color gamut and the AdobeRGB color gamut, as will be described later. That is, by using the light emitting device 10 for an image display device, for example, as shown in FIGS. 12B to 12F, a shape suitable for an image display device (that is, the above-described cover ratio is high). A chromaticity diagram can be obtained.

  Here, as a method for adjusting the color gamut of the image display device, two types of methods A and B shown in the following (1) and (2) are conceivable. That is, as the above technique, there is (1) technique A for adjusting the emission spectrum of light emitted from a wavelength conversion member provided in a light emitting device (for example, fluorescence emitted from a phosphor contained in the wavelength conversion member). Further, as the above technique, there is (2) technique B in which the transmission spectrum of transmitted light that passes through the color filter is adjusted by adjusting the pigment contained in the color filter. The method B is disclosed in Patent Document 3, for example.

  In order to improve both the light emission efficiency and the color reproduction range of the image display device, it is preferable to adjust the green color gamut by a method of adjusting the emission spectrum of the green phosphor 13 as shown in Method A. Moreover, it is preferable that the precision of the adjustment is finely adjusted precisely on the order of 1 nm.

  As shown in FIG. 2, the peak wavelength of the human visibility curve is 555 nm and exists in the green region. Therefore, for example, when the transmittance of the green color filter is adjusted to widen the green color gamut (that is, when the method B is used), the spectral component of the green region with high visibility in the emission spectrum of the light emitting device is green. It is shaved by the color filter. Therefore, when adjusting the transmission spectrum of a color filter like the said method B, the light emission efficiency of an image display apparatus provided with a light-emitting device may fall.

Therefore, the present inventors adjust the emission spectrum of the green phosphor 13 as in the method A, and have an image with a wide color reproduction range (that is, a high coverage ratio for the NTSC color gamut and Adobe RGB color gamut). An attempt was made to manufacture a light emitting device capable of realizing a display device. That is, the present inventors repeatedly made a prototype of a Mn ²⁺ activated γ-AlON phosphor, which is a green phosphor, and a light emitting device combining the prototyped Mn ²⁺ activated γ-AlON phosphor and a Mn ⁴⁺ activated phosphor. An image display device provided with the light emitting device was repeatedly manufactured. And the present inventors discovered the following subjects from the measurement results of the emission spectra of the prototype Mn ²⁺ activated γ-AlON phosphor, the light emitting device, and the image display device after intensive research.

That is, in the light emitting device, if narrower than a certain value half width of Mn ²⁺ activated gamma-AlON phosphor, Mn ²⁺ activated gamma-AlON phosphor peak wavelength of the emission spectrum of the green light becomes a wavelength shorter than the preferred wavelength emanating Further, the present inventors have found a problem that the coverage of the image display device with respect to the NTSC color gamut or the Adobe RGB color gamut decreases.

More specifically, when the half-value width of the emission spectrum of the green light emitted from the Mn ²⁺ activated γ-AlON phosphor is less than 35 nm, the peak wavelength of the Mn ²⁺ activated γ-AlON phosphor is shorter than the above preferred wavelength. As a result, the present inventors have found a problem that the coverage ratio is reduced. When the half-value width is less than 35 nm and the peak wavelength is shorter than the preferred wavelength, the coverage ratio decreases because of the green chromaticity point in the emission spectrum of light emitted from the image display device. This is because the chromaticity coordinate CIEx of (green point) becomes small.

  That is, the present inventors have found that when the half width is less than 35 nm, the color reproducibility with respect to the green region in the NTSC color gamut or AdobeRGB color gamut decreases. In other words, the present inventors improve the coverage when the half width is 35 nm or more, the peak wavelength is 518 nm or more, and the Mn concentration is 1.5 wt% or more. The present inventors have found that the color reproduction range of the image display device can be expanded.

  In addition, in a conventionally known green phosphor such as Eu-activated βSiAlON phosphor, the peak wavelength of the emission spectrum is increased by increasing the concentration of the activator incorporated in the crystal, and the half-value width is increased. It is generally known that the emission spectrum changes. However, the dependence of the concentration of the activator on the change in the emission spectrum varies depending on the type of activator and the type of base material, and varies greatly depending on the combination of each activator and base material.

For example, in the Mn ²⁺ activated γ-AlON phosphor used in the present application, the peak wavelength of the emission spectrum becomes longer as the concentration of Mn taken into the crystal becomes higher as shown in FIG. It tends to be broader. However, for example, when the production example P2 and the production example P3 are compared, the peak wavelength of the emission spectrum is longer, but the half-value width is narrower on the contrary, and the behavior opposite to the general behavior is also exhibited. . The inventors of the present invention have also identified the above range by paying attention also to the characteristics peculiar to Mn ²⁺ activated γ-AlON.

In general, it is considered that the color reproduction range of the image display device can be expanded as the half-value width of the emission spectrum of each color of red, green, and blue is narrower. That is, according to the conventional common technical knowledge, when the Mn ²⁺ activated γ-AlON phosphor has a lower Mn concentration and is limited to a lower value, the emission spectrum of the image display device is broadened. It can be said that it is preferable as a shape. Therefore, as described above, the design philosophy of producing a green phosphor in which the concentration of Mn is limited to a high value so that the half width of the emission spectrum of the green phosphor is a certain value or more is the conventional design concept. This is contrary to the design concept of a light emitting device and an image display device using a light emitting element activated phosphor. The reason for this conflict is that, for the Mn ²⁺ activated γ-AlON phosphor of the present application, in the change in the emission spectrum accompanying the increase in the concentration of the activator, the change in the peak wavelength is more than the change in the half width. This is considered to be due to the large influence on the characteristics of the display device.

Further, when the half-value width of the emission spectrum of green light emitted from the Mn ²⁺ activated γ-AlON phosphor exceeds 50 nm (that is, when the peak wavelength exceeds 528 nm), the coverage is also reduced. The reason is as follows. That is, when the full width at half maximum of the Mn ²⁺ activated γ-AlON phosphor exceeds the above value (that is, when the peak wavelength exceeds 528 nm), the area of the color gamut that can be displayed by the image display device is reduced, and the coverage ratio is increased. Decreases. In this case, the concentration of Mn contained in the Mn ²⁺ activated γ-AlON phosphor is a value exceeding 4.5 wt%.

Thus, in this embodiment, the half value width of the emission spectrum of the green light emitted from the Mn ²⁺ activated γ-AlON phosphor is 35 nm or more and 50 nm or less, and the peak wavelength is 518 nm or more and 528 nm or less. Moreover, in order to implement | achieve such a half value width and a peak wavelength, the density | concentration of Mn contained in Mn2 ⁺ activated gamma-AlON fluorescent substance is 1.5 wt% or more and 4.5 wt% or less.

The green light emitted from the Mn ²⁺ activated γ-AlON phosphor having such an emission spectrum has good wavelength matching (matching) with the transmission spectrum of the green color filter. Therefore, the light emission efficiency of the image display device including the light emitting device 10 can be improved.

In addition, CIEx, which is the x coordinate of the chromaticity coordinate of green light emitted by the Mn ²⁺ activated γ-AlON phosphor having the peak wavelength as described above, is 0.180 or more and 0.260 or less (preferably 0.225 or less). Therefore, the green light emitted from the Mn ²⁺ activated γ-AlON phosphor has good wavelength matching with a green point (green point) in a color gamut such as AdobeRGB color gamut or NTSC color gamut. Therefore, by providing the light emitting device 10 in the image display device, it is possible to realize an image display device having a higher coverage with respect to the AdobeRGB color gamut or the NTSC color gamut than the conventional image display device.

Further, even if the half-value width of the emission spectrum of green light emitted by Mn ²⁺ activated γ-AlON is widened to 35 nm or more and the peak wavelength of the emission spectrum is increased to 518 nm or more as in this embodiment, image display The green and red color reproducibility of the device in the AdobeRGB color gamut or NTSC color gamut is unlikely to deteriorate. This is because the Mn ⁴⁺ activated phosphor having a particularly narrow half-value width of the red light emission spectrum is used as the red phosphor 12.

Further, by using Mn ²⁺ activated γ-AlON that emits green light having an emission spectrum having a half-value width of 35 nm or more and a peak wavelength of 518 nm or more, in addition to the above effects, color stability of the image display device Another effect is to increase.

In the case of a Mn ²⁺ activated γ-AlON phosphor emitting green light having an emission spectrum with a half width and a peak wavelength, the excitation spectrum is important for excitation with blue light (that is, within the wavelength range of blue light). ) The full width at half maximum of the peak wavelength (excitation peak wavelength) near 445 nm widens. For this reason, even if the peak wavelength of the blue light emitted from the light emitting element 11 fluctuates due to environmental changes such as temperature and driving current, the excitation efficiency of the green phosphor 13 is unlikely to fluctuate. That is, the chromaticity of the light emitted from the light emitting device 10 is unlikely to vary. Therefore, the color stability of the image display device can be improved.

Among various phosphors, the excitation spectrum of the Mn ²⁺ activated γ-AlON phosphor has a sharp peak shape, and among them, the half-width is particularly narrow in the 445 nm excitation band. Therefore, widening the full width at half maximum of the peak wavelength near 445 nm in the excitation spectrum as described above is a particularly important characteristic in practical use.

Further, as described above, the concentration of Mn contained in the Mn ²⁺ activated γ-AlON phosphor is 1.5 wt% or more. That is, it can be said that more Mn is taken into the crystal of the Mn ²⁺ activated γ-AlON phosphor. In this case, since the absorption rate of the excitation light of the Mn ²⁺ activated γ-AlON phosphor is improved, the effect of improving the light emission efficiency of the light emitting device 10 is further obtained.

In order to incorporate more Mn into the γ-AlON crystal at a concentration in the above range, _a divalent metal element such as Mg, Zn, or Ca is used as A in the composition formula M _a A _b Al _c O _d N _e. It is preferable to add, and Mg is particularly preferable among them.

When Mg is contained in the Mn ²⁺ activated γ-AlON phosphor, the crystal structure of the γ-AlON crystal is stabilized and Mn is easily taken into the crystal. Therefore, it becomes possible to further improve the light emission efficiency of Mn ²⁺ activated γ-AlON.

Here, the index of the Mn concentration taken into the crystal is an index different from the Mn concentration in the design composition calculated from the mixing ratio of the raw material powder. That is, the concentration of Mn contained in the ^{Mn 2+} activated gamma-AlON phosphor refers to the concentration of Mn being incorporated into the crystal of ^{Mn 2+} activated gamma-AlON phosphor as a final product.

Since Mn is highly volatile, it easily volatilizes during the high-temperature firing process and is easily incorporated into the glass phase or the foreign phase outside the γ-AlON crystal. Therefore, for the concentration of Mn that is actually taken into the γ-AlON crystal and contributes to light emission, the value calculated from the design composition is not used as the index, but for example, the Mn ²⁺ activated γ-AlON crystal A value obtained by directly measuring the Mn concentration in the cross section is preferably used as the index. That is, as the index, it is preferable to use an index obtained by calculating the concentration of Mn actually taken into the crystal.

(Other members constituting the light emitting device 10)
The printed wiring board 14 is a board on which the light emitting element 11 is placed and an electric circuit for driving the light emitting element 11 is formed. The resin frame 15 is a resin frame placed on the printed wiring board 14.

  The dispersion material 16 is a member that seals the light emitting element 11. The red phosphor 12 and the green phosphor 13 are dispersed in a common dispersion material 16. The dispersion material 16 is filled inside the resin frame 15.

  The material of the dispersion material 16 is not particularly limited. For example, a translucent resin material such as methyl silicone resin, phenyl silicone resin, epoxy resin, and acrylic resin, a glass material such as low-melting glass, and an organic-inorganic hybrid glass. Etc. can be used as appropriate. In particular, when the dispersion material 16 is made of a resin material, the temperature at the time of manufacturing the dispersion material 16 is lower than that of other materials, which is preferable.

  The mixing ratio of the red phosphor 12 and the green phosphor 13 dispersed in the dispersion material 16 is not particularly limited. When the light emitting device 10 is used for an image display device, the mixing ratio may be determined as appropriate so that, for example, when the color filter is fully opened, an emission spectrum showing a desired white point can be obtained.

(Production of green phosphor)
Next, a manufacturing example of the green phosphor 13 and a comparative example thereof will be described with reference to FIGS. FIG. 3A is a graph showing the emission spectrum and excitation spectrum of the green phosphor according to Comparative Production Example P0, and FIG. 3G shows the emission spectrum of the green phosphor according to Comparative Production Example P6. It is a graph which shows an excitation spectrum. (B) to (f) and (h) of FIG. 3 are graphs showing an emission spectrum and an excitation spectrum of the green phosphor 13 according to each of Production Examples P1 to P5 and P7. 3 (b) is Production Example P1, FIG. 3 (c) is Production Example P2, FIG. 3 (d) is Production Example P3, FIG. 3 (e) is Production Example P4, and FIG. f) corresponds to Production Example P5, and FIG. 3H corresponds to Production Example P7. FIG. 4 is a table showing mixing ratios and measurement results of raw material powders of the green phosphors according to Comparative Production Examples P0 and P6 and the green phosphors 13 according to Production Examples P1 to P5 and P7. Specifically, FIG. 4 shows the peak wavelength, half-value width, and chromaticity coordinate of each emission spectrum, the half-value width of the peak wavelength near 445 nm in each excitation spectrum, and the crystal of each green phosphor. The concentration of incorporated Mn is shown.

  6A and 6B are obtained by integrating the graphs shown in FIGS. 3 and 5 (the emission spectrum and excitation spectrum of the red phosphor 12 described later). Specifically, FIG. 6A shows the emission spectrum of the green phosphor according to Comparative Production Example P0 and the green phosphor 13 according to each of Production Examples P1 to P5, and the excitation spectrum of the red phosphor 12. It is a graph. FIG. 6B is a graph showing an emission spectrum of the green phosphor according to Comparative Production Example P0 and an emission spectrum of the green phosphor 13 according to each of Production Examples P1 to P5 and an emission spectrum of the red phosphor.

  In the graphs of FIGS. 3 and 6, the vertical axis represents emission intensity (arbitrary unit), and the horizontal axis represents wavelength (nm).

(Comparative Production Example P0: Preparation of Mn ²⁺ activated γ-AlON phosphor)
First, a green phosphor manufacturing example (comparative manufacturing example P0) for comparison with the green phosphor 13 according to the present embodiment will be described with reference to FIG.

In order to produce the Mn ²⁺ activated γ-AlON phosphor according to Comparative Production Example P0, aluminum nitride powder, aluminum oxide powder and manganese carbonate powder were mixed at a mixing ratio shown in FIG.

  That is, first, a predetermined amount was weighed so as to have a composition of 12.66 mass% aluminum nitride powder, 81.78 mass% aluminum oxide powder, and 5.56 mass% manganese carbonate powder. Next, the mixture was mixed for 10 minutes or more using a mortar and pestle made of a silicon nitride sintered body to obtain a powder aggregate. The powder aggregate was naturally dropped into a boron nitride crucible having a diameter of 20 mm and a height of 20 mm.

  Next, the crucible was set in a pressure electric furnace of a graphite resistance heating type. Then, nitrogen having a purity of 99.999% by volume is introduced into the pressurized electric furnace, the pressure in the pressurized electric furnace is set to 0.5 MPa, and then the temperature is increased to 1800 ° C. at a rate of 500 ° C. per hour. did. And the said crucible was hold | maintained at 1800 degreeC for 2 hours in the said pressurization electric furnace, and the fluorescent substance sample was obtained.

  The obtained phosphor sample was pulverized using an agate mortar, and coarse powder was removed with a sieve having an opening of 100 μm to obtain phosphor powder.

The obtained phosphor powder was subjected to powder X-ray diffraction measurement (XRD; X-ray diffraction) using Cu Kα rays. As a result, all the charts obtained from the phosphor powder confirmed that the phosphor powder had a γ-AlON structure. Moreover, as a result of irradiating the phosphor powder with light having a wavelength of 365 nm, it was confirmed that the phosphor powder emitted green light. That is, the Mn ²⁺ activated γ-AlON phosphor powder according to Comparative Production Example P0 was obtained through the above steps.

  Then, the emission spectrum shown to (a) of FIG. 3 was obtained by irradiating the light of 445 nm with respect to the obtained green fluorescent substance concerning the comparative manufacture example P0. Specifically, the emission spectrum is measured by irradiating the green phosphor with 445 nm light using a spectrophotometer (manufactured by Otsuka Electronics: MCPD-7000) to excite the green phosphor. It was. The excitation spectrum is obtained by monitoring the peak wavelength of the emission spectrum.

  As a result of analyzing the emission spectrum shown in FIG. 3A, as shown in FIG. 4, the peak wavelength of the emission spectrum of the green phosphor according to Comparative Production Example P0 was 515 nm, and the half width was 33 nm. Further, when the chromaticity coordinates were calculated from the emission spectrum, the CIE1931 chromaticity coordinates were (CIEx, CIEy) = (0.143, 0.727).

  Next, the concentration of Mn taken into the crystal of the green phosphor according to Comparative Production Example P0 was measured.

  Here, the concentration of Mn taken into the crystal of the green phosphor was calculated as follows. That is, first, the phosphor powder obtained through the above steps was dispersed in an epoxy resin (manufactured by JEOL Ltd.). Next, using a cross-section processing apparatus (manufactured by JEOL Ltd.), the phosphor embedded in the epoxy resin was cut by irradiating the epoxy resin in which the phosphor powder was dispersed with an Ar ion beam. After that, the Mn concentration was measured on multiple cut surfaces using an EDX (Energy dispersive X-ray spectrometry) detector (energy dispersive X-ray analyzer; manufactured by Ametech) attached to the SEM (Scanning Electron Microscope) device. The average value was calculated. The average value was calculated as the Mn concentration.

  The concentration of Mn taken into the crystal of the green phosphor according to Comparative Production Example P0 calculated by the above method was 0.45 wt% as shown in FIG.

  As shown in FIG. 4, the half width of the peak wavelength near 445 nm in the excitation spectrum of the green phosphor according to Comparative Production Example P0 was 22 nm.

(Comparative Production Example P6: Preparation of Mn ²⁺ activated γ-AlON phosphor)
Next, another production example (comparative production example P6) of the green phosphor for comparison with the green phosphor 13 according to the present embodiment will be described with reference to FIG.

  The green phosphor according to Comparative Production Example P6 was also produced through the same process as Comparative Production Example P0. That is, the green phosphor according to Comparative Production Example P6 was produced by mixing aluminum nitride powder, aluminum oxide powder, magnesium oxide powder, and manganese fluoride powder at a mixing ratio shown in FIG. Then, the light emission spectrum shown to (g) of FIG. 3 was obtained by irradiating the light of 445 nm with respect to the green fluorescent substance which concerns on the comparative manufacture example P6. Specifically, this emission spectrum is obtained by irradiating the green phosphor with 445 nm light using a spectrophotometer (manufactured by Otsuka Electronics: MCPD-7000) as in Comparative Production Example P0. Was measured by exciting. The excitation spectrum is obtained by monitoring the peak wavelength of the emission spectrum. Further, the concentration of Mn incorporated in the green phosphor crystal according to Comparative Production Example P6 was also calculated in the same manner as in Comparative Production Example P0.

  As shown in FIG. 4, the peak wavelength of the emission spectrum of the green phosphor according to Comparative Production Example P6 was 529 nm, and the half width was 51 nm. Further, when the chromaticity coordinates were calculated from the emission spectrum, the CIE1931 chromaticity coordinates were (CIEx, CIEy) = (0.262, 0.690). Further, the concentration of Mn taken into the crystal of the green phosphor according to Comparative Production Example P6 is 4.56 wt%, and the half width of the peak wavelength near 445 nm in the excitation spectrum of the green phosphor is 25. It was 5 nm.

(Production Examples P1 to P5 and P7: Preparation of Mn ²⁺ activated γ-AlON phosphor)
Next, manufacturing examples (manufacturing examples P1 to P5 and P7) of the green phosphor 13 according to the present embodiment will be described with reference to (b) to (f) and (h) of FIG.

Mn ²⁺ activated γ-AlON phosphors (green phosphor 13) according to Production Examples P1 to P5 and P7 were produced through the same steps as in Comparative Production Example P0. That is, the green phosphor 13 according to Production Example P1 was prepared by mixing aluminum nitride powder, aluminum oxide powder, magnesium oxide powder, and manganese carbonate powder at a mixing ratio shown in FIG. The green phosphor 13 according to Production Example P2 was produced by mixing aluminum nitride powder, aluminum oxide powder, magnesium oxide powder, and manganese oxide powder at a mixing ratio shown in FIG. The green phosphors 13 according to Production Examples P3 to 5 and P7 were produced by mixing aluminum nitride powder, aluminum oxide powder, magnesium oxide powder, and manganese fluoride powder in a mixing ratio shown in FIG.

  Thereafter, the emission spectra shown in (b) to (f) and (h) of FIG. 3 are obtained by irradiating each of the obtained green phosphors 13 according to Production Examples P1 to P5 and P7 with light of 445 nm. Got. Specifically, this emission spectrum is obtained by irradiating the green phosphor with 445 nm light using a spectrophotometer (manufactured by Otsuka Electronics: MCPD-7000) as in Comparative Production Example P0. Was measured by exciting. The excitation spectrum is obtained by monitoring the peak wavelength of the emission spectrum. Furthermore, the concentration of Mn taken into the crystals of the green phosphor 13 according to Production Examples P1 to P5 and P7 was also calculated by the same method as in Comparative Production Example P0.

  As shown in FIG. 4, in the green phosphor 13 according to Production Examples P1 to P5 and P7, it can be seen that the half width of the emission spectrum is 35 nm or more and 50 nm or less, unlike Comparative Production Examples P0 and P6. Moreover, it turns out that the peak wavelength of the said emission spectrum is 518 nm or more and 528 nm or less. Further, it is understood that CIEx that is the x coordinate of the chromaticity coordinates is 0.180 or more and 0.260 or less. Moreover, it turns out that the density | concentration of the said Mn is 1.5 wt% or more and 4.5 wt% or less.

  Therefore, by using the green phosphors 13 according to the manufacturing examples P1 to P5 and P7, the coverage ratio is higher with respect to the AdobeRGB color gamut or the NTSC color gamut and the light emission efficiency is better than the conventional image display device. An image display device can be realized.

  Further, in the green phosphor 13 according to Production Examples P1 to P5 and P7, the half width of the emission spectrum is wider than that of Comparative Production Example P0. Accordingly, it can be seen that the half width of the peak wavelength near 445 nm in the excitation spectrum of the green phosphor 13 according to Production Examples P1 to P5 and P7 is 23 nm to 25.5 nm, which is wider than that of Comparative Production Example P0. Therefore, the color stability of the image display device can be improved by using the green phosphor 13 according to Production Examples P1 to P5 and P7.

(Production of red phosphor)
Next, the red phosphor 12 will be described with reference to FIG. FIG. 5 is a graph showing an emission spectrum and an excitation spectrum of the red phosphor 12 according to Production Example R1. In Production Example R1, a Mn ⁴⁺ activated K ₂ SiF ₆ phosphor is produced as the red phosphor 12.

(Production Example R1: Preparation of Mn ⁴⁺ activated K ₂ SiF ₆ phosphor)
In the composition formula (A) represented by the above-mentioned MI ₂ (MII _1-h Mn _h ) F ₆ , MI is K, MII is Si, and Mn ⁴⁺ activated fluorine complex phosphor in which h = 0.06. Was prepared by the following procedure.

  First, a fluororesin-based ion exchange membrane partition (diaphragm) is provided in the center of the reaction vessel made of vinyl chloride resin, and an anode and a cathode made of a platinum plate are installed in each of the two chambers sandwiching the ion exchange membrane. did. A hydrofluoric acid aqueous solution in which manganese (II) was dissolved was placed on the anode side of the reaction tank, and a hydrofluoric acid aqueous solution was placed on the cathode side.

The anode and cathode were connected to a power source, and electrolysis was performed at a voltage of 3 V and a current of 0.75 A. After the electrolysis, when an excess of potassium fluoride solution saturated with hydrofluoric acid aqueous solution was added to the reaction solution on the anode side, K ₂ MnF ₆ was produced as a yellow solid product. The produced yellow solid product was separated by filtration and collected to obtain K ₂ MnF ₆ .

Next, 4.8 g of silicon dioxide was dissolved in a 48% by mass hydrofluoric acid aqueous solution of 100 cm ³ to prepare an aqueous solution containing silicon fluoride. The aqueous solution was allowed to cool to room temperature, then placed in a resin container with a lid, kept in a water bath maintained at 70 ° C. for 1 hour or longer, and heated. To this aqueous solution containing silicon fluoride, 1.19 g of the prepared K ₂ MnF ₆ powder was added and dissolved by stirring to prepare an aqueous solution (first solution) containing silicon fluoride and K ₂ MnF ₆ .

Further, 13.95 g of potassium fluoride was dissolved in a 40 cm ³ 48% by mass hydrofluoric acid aqueous solution and allowed to cool to room temperature to prepare an aqueous solution containing potassium fluoride (second solution).

Thereafter, the second solution was added little by little to the stirred first solution over about 2.5 minutes, and when stirred for about 10 minutes, a pale orange solid was produced. The solid product was filtered off, and the filtered solid product was washed with a small amount of 20% by mass aqueous hydrofluoric acid solution. Thereafter, the solid product was further washed with ethanol and then vacuum-dried. As a result, Mn ⁴⁺ activated K ₂ SiF ₆ phosphor powder according to Production Example R1 was obtained.

The obtained phosphor powder was subjected to powder X-ray diffraction measurement (XRD) using Cu Kα rays. As a result, all the charts obtained from the phosphor powder confirmed that the phosphor powder had a K ₂ SiF ₆ structure. Moreover, as a result of irradiating the phosphor powder with light having a wavelength of 365 nm, it was confirmed that the phosphor powder emitted red light.

  Then, the emission spectrum shown in FIG. 5 was obtained by irradiating light of 445 nm with respect to the obtained red phosphor 12 according to Production Example R1. Specifically, the emission spectrum is measured by irradiating the red phosphor 12 with 445 nm light using a spectrophotometer (manufactured by Otsuka Electronics: MCPD-7000) to excite the red phosphor. It was done. The excitation spectrum is obtained by monitoring the peak wavelength of the emission spectrum.

  FIG. 5 shows that the emission spectrum of the red phosphor 12 according to Production Example R1 has good wavelength matching with the red color filter 126r shown in FIG. Further, as a result of analyzing the emission spectrum shown in FIG. 5, the peak wavelength of the emission spectrum of the red phosphor 12 according to Production Example R1 was 630 nm, and the half width was 8 nm. Further, when the chromaticity coordinates were calculated from the emission spectrum, the CIE1931 chromaticity coordinates were (CIEx, CIEy) = (0.691, 0.307).

(Examples and comparative examples of light emitting devices)
Next, the light emitting device 10 and a comparative example thereof will be described with reference to FIGS. FIG. 7A is a graph showing an emission spectrum of the light emitting device according to Comparative Example D0, and FIG. 7G is a graph showing an emission spectrum of the light emitting device according to Comparative Example D6. (B) to (f) and (h) of FIG. 7 are graphs showing emission spectra of the light emitting device 10 according to Examples D1 to D5 and D7. 7 (b) shows Example D1, FIG. 7 (c) shows Example D2, FIG. 7 (d) shows Example D3, FIG. 7 (e) shows Example D4, FIG. f) corresponds to Example D5, and (h) of FIG. 7 corresponds to Example D7. In the graph of FIG. 7, the vertical axis represents emission intensity (arbitrary unit), and the horizontal axis represents wavelength (nm). FIG. 8 shows a mixing ratio of the red phosphor and the green phosphor dispersed in the dispersion material (resin) in the light emitting device 10 according to each of Examples D1 to D5 and D7 and each of Comparative Examples D0 and D6. And it is a table | surface which shows the mixing ratio of a dispersing material, a red fluorescent substance, and a green fluorescent substance.

(Comparative Example D0)
First, a manufacturing example (comparative example D0) of a light emitting device for comparison with the light emitting device 10 according to the present embodiment will be described with reference to FIG. 7A and FIG.

The light emitting device according to Comparative Example D0 has the same structure as the light emitting device 10 having the structure shown in FIG. In the light emitting device according to Comparative Example D0, the light emitting element is a blue LED (manufactured by Cree) having an emission peak wavelength of 445 nm. The red phosphor is the Mn ⁴⁺ activated K ₂ SiF ₆ phosphor obtained in Production Example R1. The green phosphor is the Mn ²⁺ activated γ-AlON phosphor obtained in the comparative production example P0. The dispersion material is a silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd .: KER-2500).

First, as the phosphor dispersed in the silicone resin, the Mn ⁴⁺ activated K ₂ SiF ₆ phosphor of Production Example R1 and the Mn ²⁺ activated γ-AlON phosphor of Comparative Production Example P0 are mixed at a weight ratio of 1:38. As a result, a phosphor mixture was obtained.

  Next, this phosphor mixture was dispersed in a silicone resin to obtain a phosphor-dispersed resin. Specifically, the phosphor dispersion resin was obtained by mixing the phosphor mixture and the silicone resin in a weight ratio of 1: 0.5.

Thereafter, the obtained light-emitting device was driven at a drive current of 20 mA, and the emission spectrum was measured with a spectrophotometer (manufactured by Otsuka Electronics: MCPD-7000). As a result, the emission spectrum shown in FIG. In Comparative Example D0, the amount of dispersion of the Mn ^{4 +} activated K ₂ SiF ₆ phosphor and the Mn ²⁺ activated γ-AlON phosphor is the transmission spectrum shown in FIG. When passing through a liquid crystal panel including a color filter, the white point is adjusted to be white at around 10,000K.

(Comparative Example D6)
Next, another manufacturing example (Comparative Example D6) of the light emitting device for comparison with the light emitting device 10 according to the present embodiment will be described with reference to FIG.

The light emitting device according to Comparative Example D6 has the same structure as the light emitting device 10 having the structure shown in FIG. In the light emitting device according to Comparative Example D6, the light emitting element is a blue LED (manufactured by Cree) having an emission peak wavelength of 445 nm. The red phosphor is the Mn ⁴⁺ activated K ₂ SiF ₆ phosphor obtained in Production Example R1. The green phosphor is the Mn ²⁺ activated γ-AlON phosphor obtained in Comparative Production Example P6. The dispersion material is a silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd .: KER-2500).

In the light emitting device according to Comparative Example D6, as the phosphor dispersed in the silicone resin, Mn ⁴⁺ activated K ₂ SiF ₆ phosphor of Production Example R1 and Mn ²⁺ activated γ-AlON phosphor of Comparative Production Example P6 are 1 : The mixture was mixed at a weight ratio of 20.5 to obtain a phosphor mixture.

  Next, this phosphor mixture was dispersed in a silicone resin to obtain a phosphor-dispersed resin. Specifically, this phosphor dispersion resin was obtained by mixing the phosphor mixture and the silicone resin in a weight ratio of 1: 0.80.

Then, when the emission spectrum was measured similarly to the light-emitting device concerning the comparative example D0, the emission spectrum shown to (g) of FIG. 7 was obtained. In Comparative Example D6, the amount of dispersion of Mn ^{4 +} activated K ₂ SiF ₆ phosphor and Mn ²⁺ activated γ-AlON phosphor is prepared in the same manner as Comparative Example D0.

(Examples D1-D5 and D7)
Next, manufacturing examples (Examples D1 to D5 and D7) of the light emitting device 10 according to the present embodiment will be described with reference to FIGS. 7B to 7F and FIG.

The light emitting device 10 according to each of Examples D1 to D5 and D7 has the structure shown in FIG. In the light emitting device 10 according to each of Examples D1 to D5 and D7, the light emitting element 11 is a blue LED (manufactured by Cree) having an emission peak wavelength of 445 nm. The red phosphor 12 is the Mn ⁴⁺ activated K ₂ SiF ₆ phosphor obtained in Production Example R1. The green phosphor 13 is the Mn ²⁺ activated γ-AlON phosphor obtained in each of the above production examples P1 to P5 and P7. The dispersion material 16 is a silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd .: KER-2500).

As in Comparative Example D0, as phosphors dispersed in the silicone resin, Mn ⁴⁺ activated K ₂ SiF ₆ phosphor of Production Example R1 and Mn ²⁺ activated γ-AlON phosphors of Production Examples P1 to P5 and P7 were used. Mixing was performed at a weight ratio shown in FIG. 8 to obtain a phosphor-dispersed resin.

FIG. 8 shows the weight ratio of the green phosphor 13 to the red phosphor 12. For example, in Example D1, Mn ⁴⁺ activated K ₂ SiF ₆ phosphor according to Production Example R1 and Mn ²⁺ activated γ-AlON phosphor according to Production Example P1 were mixed at a weight ratio of 1: 27.8.

  Next, this phosphor mixture was dispersed in a silicone resin to obtain a phosphor-dispersed resin. Specifically, this phosphor-dispersed resin was obtained by mixing the phosphor mixture and the silicone resin at a weight ratio shown in FIG.

In FIG. 8, the weight ratio of the silicone resin to the red phosphor 12 and the green phosphor 13 is shown. For example, in Example D1, the weight ratio of Mn ^{4 +} activated K ₂ SiF ₆ phosphor according to Production Example R1 and Mn ²⁺ activated γ-AlON phosphor according to Production Example P1 and silicone resin is 1: 0.54. Mixed with.

Thereafter, the obtained light-emitting device was driven at a drive current of 20 mA, and the emission spectrum was measured with a spectrophotometer (manufactured by Otsuka Electronics: MCPD-7000). The results shown in (b) to (f) and (h) of FIG. The emission spectrum shown was obtained. In each of Examples D1 to D5 and D7, as in Comparative Example D0, the amounts of dispersion of Mn ^{4 +} activated K ₂ SiF ₆ phosphor and Mn ²⁺ activated γ-AlON phosphor are shown in (b) to ( When the emission spectra shown in f) and (h) are transmitted through a liquid crystal panel including a color filter having a transmission spectrum shown in FIG. 10 to be described later, the white point is adjusted to be white at around 10,000K.

  By using the light emitting device 10 thus obtained as a backlight of the image display device, an image display device with high luminous efficiency and a wide color reproduction range can be realized. Details will be described in the second embodiment.

[Embodiment 2]
The second embodiment will be described below with reference to FIGS. In the present embodiment, an image display device 100 including the light emitting device 10 according to the first embodiment will be described. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

(Image display device 100)
FIG. 9A is an exploded perspective view of an image display apparatus 100 which is an example of the image display apparatus according to the present embodiment. FIG. 9B is an exploded perspective view of the liquid crystal display device 120a included in the image display device 100 shown in FIG. FIG. 10 is a graph showing a transmission spectrum of the color filter included in the image display apparatus 100.

  As shown in FIG. 9A, the image display device 100 includes a light emitting device 10, a light guide plate 110, and a liquid crystal display unit 120. The light guide plate 110 is a transparent or translucent light guide plate. The liquid crystal display unit 120 is a display unit that displays an image, and includes a plurality of liquid crystal display devices 120a.

  In the image display device 100, a plurality of light emitting devices 10 are arranged on the side surface of the light guide plate 110. In the present embodiment, as shown in FIG. 9A, six light emitting devices 10 are arranged. Further, adjacent to the light guide plate 110, a liquid crystal display unit 120 including a plurality of liquid crystal display devices 120a is provided. The emitted light 130 from the light emitting device 10 is scattered in the light guide plate 110 and is irradiated as scattered light 140 on the entire surface of the liquid crystal display unit 120.

(Liquid crystal display device 120a)
As shown in FIG. 9B, the liquid crystal display device 120a constituting the liquid crystal display unit 120 includes a polarizing plate 121, a transparent conductive film 123a (having a thin film transistor 122), an alignment film 124a, a liquid crystal layer 125, The alignment film 124b, the upper thin film electrode 123b, the color filter 126 for displaying color pixels, and the upper polarizing plate 127 are sequentially stacked.

  The color filter 126 is divided into portions having a size corresponding to each pixel of the transparent conductive film 123a. The color filter 126 includes a red color filter 126r that transmits red light, a green color filter 126g that transmits green light, and a blue color filter 126b that transmits blue light.

  The image display apparatus 100 according to the present embodiment preferably includes filters that transmit red light, green light, and blue light, respectively, like a color filter 126 illustrated in FIG. In this case, as each color filter, for example, a filter showing the transmission spectrum shown in FIG. 10 can be suitably used. Also in the examples described later, the color filter showing the transmission spectrum shown in FIG. 10 is used.

  Here, the transmittance of the green color filter 126g of the present embodiment is generally higher than the transmittance of the green color filter used in the wide color gamut liquid crystal display. More specifically, the transmittance of light in the wavelength region of 520 nm or more and 540 nm or less of the green color filter 126g is 80% or more.

In general, when the transmittance of the green color filter is high as described above, the green color reproducibility is lowered. On the other hand, in the light emitting device 10 included in the image display device 100 of the present embodiment, the above-described Mn ²⁺ activated γ-AlON phosphor is used as the green phosphor 13. Therefore, even when the green color filter having a high transmittance as described above is used as the green color filter 126g, the color reproduction range of the image display device 100 can be widened. In addition, since a green color filter with high transmittance can be used as the green color filter 126g, the luminance of the image display device 100 can be improved. That is, the image display device 100 can realize both the brightness of the image displayed by the image display device 100 and a wide color reproduction range.

(Example of image display device and comparative example)
Next, examples of the image display apparatus 100 and comparative examples thereof will be described with reference to FIGS. 11 and 12. FIG. 11 is a table showing the coverage, area ratio, and chromaticity coordinates of the image display devices 100 according to the respective examples DIS1 to DIS5 and DIS7 of this embodiment and the image display devices of the comparative examples DIS0 and DIS6. . FIG. 12 is a graph comparing the color gamut of the image display device 100 according to each of the examples DIS1 to DIS5 and DIS7 of this embodiment, or the image display device of the comparative examples DIS0 and DIS6, and the color gamut of NTSC and AdobeRGB. It is.

(Comparative Examples DIS0 and DIS6)
The image display devices according to comparative examples DIS0 and DIS6 have the same structure as the image display device 100 having the structure shown in FIG. In the image display device according to Comparative Example DIS0, the light emitting device of Comparative Example D0 was used as the backlight. Further, in the image display device according to Comparative Example DIS6, the light emitting device of Comparative Example D6 was used as the backlight. In the image display devices according to comparative examples DIS0 and DIS6, color filters having the transmittance shown in FIG. 10 were used. That is, the color filter 126 including the red color filter 126r, the green color filter 126g, and the blue color filter 126b was used.

(Examples DIS1 to DIS5 and DIS7)
The image display device 100 according to the embodiments DIS1 to DIS5 and DIS7 has the structure shown in FIG. As the backlight, the light emitting devices 10 of Examples D1 to D5 and D7 were used, respectively. As the color filter, the color filter 126 having the transmittance shown in FIG. 10 was used.

(Comparison of color gamut of image display devices)
In the image display device of each example and each comparative example, (1) chromaticity coordinates of white point, red point, green point, blue point in CIE1931 chromaticity coordinates of on-screen display light, (2) NTSC coverage and FIG. 11 shows the area ratio, (3) AdobeRGB cover ratio, and area ratio.

  Here, the red point, the green point, and the blue point are chromaticity points on the display when only light that passes through the red color filter, green color filter, and blue color filter is displayed on the display (on the screen), respectively. It is. The white point is a chromaticity point on the display when all the light transmitted through the respective color filters is simultaneously displayed. The NTSC coverage is the ratio of the area covered by the color gamut surrounded by the red point, green point, and blue point to the area of the NTSC color gamut. The NTSC area ratio is the ratio of the area of the color gamut surrounded by the red point, green point, and blue point to the area of the NTSC color gamut. Similarly, the AdobeRGB cover ratio is the ratio of the area covered by the color gamut surrounded by the red point, green point, and blue point to the area of the AdobeRGB color gamut. The AdobeRGB area ratio is the ratio of the area of the color gamut surrounded by the red point, green point, and blue point to the area of the AdobeRGB color gamut.

  The chromaticity points, NTSC coverage and area ratio, and AdobeRGB coverage and area ratio shown in FIG. 11 were calculated from spectral data measured using MCPD-7000 manufactured by Otsuka Electronics.

  From the parameters of each of the examples DIS1 to DIS5 and DIS7 and the comparative example DIS0 shown in FIG. 11, the NTSC area ratio and AdobeRGB area ratio of the image display device 100 of each of the examples DIS1 to DIS5 and DIS7 are the images of the comparative example DIS0. It can be seen that it is lower than the NTSC area ratio and AdobeRGB area ratio of the display device. On the other hand, it can be seen that the NTSC cover ratio and Adobe RGB cover ratio of the image display devices 100 of the respective examples DIS1 to DIS5 and DIS7 are higher than the NTSC cover rate and Adobe RGB cover rate of the image display device of the comparative example DIS0, respectively. .

  The above effect will be described with reference to (a) to (f) and (h) of FIG. FIG. 12A is a graph comparing the color gamut of the image display device of comparative example DIS0 with the NTSC and AdobeRGB color gamuts. (B) to (f) and (h) of FIG. 12 are graphs comparing the color gamuts of the image display apparatuses of Examples DIS1 to DIS5 and DIS7 with the color gamuts of NTSC and AdobeRGB, respectively.

  In each of (a) to (f) and (h) of FIG. 12, the color gamut in the vicinity of (CIEx, CIEy) = (0.2, 0.7) is the green color gamut. Comparing (a) of FIG. 12 with (b) to (f) and (h) of FIG. 12, the image display device 100 of each of the examples DIS1 to DIS5 and DIS7 is similar to the image display device of the comparative example DIS0. By comparison, it can be seen that the green color gamut matches well with the NTSC color gamut and the AdobeRGB color gamut. More specifically, in FIG. 12A, the color gamut of the image display device shown in the comparative example DIS0 is such that the green point is too close to the left side in the figure, that is, in the direction in which CIEx is small, NTSC and AdobeRGB. There is a green point in a region that is far from the color gamut. Therefore, although the color gamut of the image display device shown in comparative example DIS0 has a wide area, the coverage with respect to the NTSC and AdobeRGB color gamuts is low.

  Further, regarding the blue color gamut, the color gamut of the image display device 100 of each of the examples DIS1 to DIS5 and DIS7 is the image display device of the comparative example DIS0 from FIGS. 12 (a) to (f) and (h). It can be seen that the color gamut is closer to the NTSC color gamut and AdobeRGB color gamut.

  Further, from the parameters of the examples DIS1 to DIS5 and DIS7 and the comparative example DIS6 shown in FIG. 11, the NTSC area ratio and AdobeRGB area ratio of the image display device 100 of each of the examples DIS1 to DIS5 and DIS7 are the same as those of the comparative example DIS6. It is higher than the NTSC area ratio and AdobeRGB area ratio of the image display device. Further, the NTSC cover rate and Adobe RGB cover rate of the image display devices 100 of the respective examples DIS1 to DIS5 and DIS7 are also higher than the NTSC cover rate and Adobe RGB cover rate of the image display device of the comparative example DIS6, respectively. I understand.

  The above effect will be described with reference to FIGS. FIG. 12G is a graph comparing the color gamut of the image display device of Comparative Example DIS6 with the NTSC and AdobeRGB color gamuts.

  In each of FIGS. 12B to 12H, the image display devices 100 of the respective examples DIS1 to DIS5 and DIS7 have an NTSC color gamut in the green color gamut compared to the image display device of the comparative example DIS6. It can be seen that the color gamut of AdobeRGB and the matching are good. More specifically, the color gamut of the image display device shown in comparative example DIS6 is that the green point does not deviate significantly from the NTSC and AdobeRGB color gamuts, but the green point is the lower right side in the figure, ie, CIEx. Is too large and CIEy is too small. Therefore, the color gamut of the image display device shown in the comparative example DIS6 has a small area, and the coverage with respect to the NTSC and AdobeRGB color gamuts is also low.

  Therefore, it can be seen that the image display devices of the respective examples DIS1 to DIS5 and DIS7 are more practical than the image display devices of the comparative examples DIS0 and DIS6.

From the above results, the peak wavelength and half width of the emission spectrum of the green phosphor 13 which is the Mn ²⁺ activated γ-AlON phosphor used in the present invention are appropriately set in the configuration combined with the Mn ⁴⁺ activated phosphor. Due to that. In addition, it can be said that the Mn concentration contained in the Mn ²⁺ activated γ-AlON phosphor used in the present invention is also appropriately set in the configuration combined with the Mn ⁴⁺ activated phosphor.

  In Patent Document 2, only the NTSC area ratio of the image display device is discussed. However, in order to actually improve the color gamut of the image display device, it is important to improve the coverage ratio for the NTSC color gamut and the color gamut such as AdobeRGB. More specifically, in the configuration of Patent Document 2, the NTSC area ratio is improved, but the NTSC cover ratio more important than the NTSC area ratio is not discussed in practice, and the actual cover ratio is not high. . For this reason, when the image display device of Patent Document 2 is used as a display device compliant with standards such as NTSC and AdobeRGB, there is a possibility that the color gamut that can be substantially displayed becomes narrow.

The image display device 100 according to the present embodiment includes the light emitting device 10 according to the first embodiment. That is, as described in embodiment 1, as the wavelength converting member of a light emitting device 10 is controlled peak wavelength and half width of the emission spectrum, and Mn concentration of Mn taken into the crystal is controlled ²⁺ activated γ -An AlON phosphor is used as the green phosphor 13. The green phosphor 13 is used in combination with the Mn ⁴⁺ activated phosphor as the red phosphor 12.

  Therefore, as described above, it is possible to realize the image display device 100 having a high NTSC cover ratio and Adobe RGB cover ratio and high luminous efficiency.

[Embodiment 3]
The third embodiment will be described below with reference to FIG. In the present embodiment, a light emitting device 10a according to another embodiment of the light emitting device 10 described in the first embodiment will be described. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

(Light Emitting Device 10a)
As shown in FIG. 13, the light emitting device 10 a includes a light emitting element 11, a red phosphor 12, a green phosphor 13, a printed wiring board 14, a resin frame 15, a dispersion material 16, a light scattering material (scattering). Material) 17. That is, the light emitting device 10 a according to the present embodiment is different from the light emitting device 10 according to the first embodiment in that the light scattering material 17 is included.

(Light scattering material 17)
The light scattering material 17 scatters blue light emitted from the light emitting element 11. The light scattering material 17 is uniformly dispersed in the dispersion material 16 together with the red phosphor 12 and the green phosphor 13. As the light scattering material 17, a metal oxide such as SiO ₂ , Al ₂ O ₃ , Y ₂ O ₃ , Zr ₂ O ₃ , or TiO ₂ can be suitably used. Among these, Al ₂ O ₃ or Y ₂ O ₃ having a high refractive index and a low visible light absorption rate can be more suitably used as the light scattering material 17.

  In the present embodiment, the particle size of the light scattering material 17 is 50 nm or more and 5 μm or less. When the particle diameter of the light scattering material 17 is out of the above range, the blue light scattering efficiency may be lowered. Therefore, as the light scattering material 17, a material having a particle size in the above range can be suitably used.

  As described above, since the light emitting device 10a of the present embodiment includes the light scattering material 17, the blue light (excitation light) emitted from the light emitting element 11 can be efficiently scattered. That is, the light emitting device 10 a can efficiently irradiate the blue light with the red phosphor 12 and the green phosphor 13. Therefore, the usage amount of the red phosphor 12 and the green phosphor 13 used in the light emitting device 10a (that is, the weight of the red phosphor 12 and the green phosphor 13) can be reduced. Therefore, it is possible to reduce the weight of the light emitting device 10a, and thus to reduce the weight of the image display device including the light emitting device 10a.

The light emitting device 10 according to the first embodiment and the light emitting device 10a according to the present embodiment use a Mn ²⁺ activated γ-AlON phosphor as the green phosphor 13 and a Mn ⁴⁺ activated phosphor as the red phosphor 12. That is, in the light emitting devices 10 and 10a, indirect transition type Mn is used as the light emitting element. Therefore, the transition probability in the light absorption of the red phosphor 12 and the green phosphor 13 is lowered. In order to improve the light emission efficiency by improving the transition probability, it is necessary to increase the amount of the red phosphor 12 and the green phosphor 13 dispersed in the dispersion material 16.

In the light emitting device 10a, since the light scattering material 17 is dispersed inside the dispersion material 16, the usage amount of the red phosphor 12 and the green phosphor 13 can be reduced as described above. Therefore, it is possible to suppress an increase in the usage amount due to a decrease in transition probability. That is, it can be said that the light scattering material 17 plays an important role in the light emitting device using the Mn ²⁺ activated γ-AlON phosphor and the Mn ⁴⁺ activated phosphor.

[Embodiment 4]
A fourth embodiment will be described. The fourth embodiment is another embodiment of the light emitting device described in the first embodiment. Since the light emitting device according to this embodiment is the same as the light emitting device 10 except for the light emitting element 11, the description thereof is omitted.

  In the light emitting device according to the present embodiment, the peak wavelength of the primary light (excitation light) emitted from the light emitting element is 420 nm or more and 440 nm or less. Even with such a light emitting element that emits primary light (excitation light) of a peak wavelength, it is possible to provide a light emitting device that can realize an image display device with a wide color reproduction range.

  However, as described above, the light emitting device 10 of Embodiment 1 has good wavelength matching between the peak wavelength of the primary light (excitation light) and the excitation spectrum of the red phosphor 12 and the transmission spectrum of the blue color filter 126b. Luminous efficiency is higher than that of the light emitting device of this embodiment.

(Relationship between peak wavelength of primary light and luminous efficiency)
Here, the relationship between the peak wavelength of the primary light and the light emission efficiency will be described with reference to FIG. FIG. 14 shows the mixing ratio of the green phosphor 13 and the red phosphor 12 dispersed in the dispersion material 16 and the dispersion material 16 and the green phosphor in the light emitting device 10 according to Examples D8 and D9 of this embodiment. 13 is a table showing the mixing ratio between the No. 13 and the red phosphor 12 and the luminous efficiency. For comparison of luminous efficiency, FIG. 14 also shows data of the light emitting device 10 according to Example D5 of Embodiment 1. FIG. 14 shows the luminous flux values (relative values) of the light emitting devices according to the respective examples when the luminous flux value (luminous efficiency) of the light emitting device 10 according to Example D5 is 100.

  As shown in FIG. 14, in Example D8 of the present embodiment, the peak wavelength of the primary light (excitation light) emitted from the light emitting element 11 is 430 nm. In Example D9 of this embodiment, the peak wavelength of the primary light is 440 nm. Further, in Examples D8 and D9 of the present embodiment, the green phosphor 13 manufactured in Production Example P5 is used as in Example D5, and the red fluorescent light is mixed at the mixing ratio shown in FIG. The body 12 and the green phosphor 13 are dispersed in the dispersion material 16. Further, the mixing amount of the red phosphor 12, the green phosphor 13 and the dispersion material 16 in Examples D8 and D9 is the same as in Examples D1 to D5 and D7 described above, and the liquid crystal including the color filter having the transmission spectrum shown in FIG. When the light passes through the panel, the chromaticity point indicating the white point is adjusted to be white at a color temperature of 10,000 K near (CIEx, CIEy) = (0.281, 0.288).

  As shown in FIG. 14, the luminous efficiency of Example D8 (peak wavelength of light emitting element 11: 430 nm) is 81 when the luminous efficiency of Example D5 (peak wavelength of light emitting element 11: 445 nm) is 100. . Thus, the luminous efficiency of Example D8 is lower than the luminous efficiency of Example D5 as described above. However, it can be said that the luminous efficiency of Example D8 is such that the desired luminous efficiency that can be achieved in the image display device of the present application can be achieved.

  The light emission efficiency of Example D9 (peak wavelength of light-emitting element 11: 440 nm) is 96 when the light emission efficiency of Example D5 is set to 100. Thus, it can be said that the luminous efficiency of Example D9 has realized the luminous efficiency comparable to Example D5.

  From the result of FIG. 14, when the peak wavelength of the primary light emitted from the light emitting element 11 is 420 nm or more and 440 nm or less, a predetermined light emission efficiency can be realized. Therefore, the light emitting device 10 according to this embodiment can be suitably used for the image display device of the present application.

[Embodiment 5]
The fifth embodiment will be described below with reference to FIGS. In the present embodiment, an image display device 200 including the light emitting device 10 will be described. For convenience of explanation, members having the same functions as those described in the embodiment are given the same reference numerals, and descriptions thereof are omitted.

(Image display device 200)
FIG. 15A is an exploded perspective view of an image display apparatus 200 which is an example of the image display apparatus according to the present embodiment. FIG. 15B is an exploded perspective view of the liquid crystal display device 120b included in the image display device 200 shown in FIG. FIG. 16 is a graph showing a transmission spectrum of the color filter 126 ′ included in the image display device 200.

  As illustrated in FIG. 15, the image display device 200 according to the present embodiment is different from the image display device 100 according to the second embodiment in that a liquid crystal display device 120 b is included. Specifically, the image display apparatus 200 is different from the image display apparatus 100 in that the image display apparatus 200 includes a color filter 126 ′ having a red color filter 126 r, a green color filter 126 g ′, and a blue color filter 126 b ′. That is, the image display device 200 replaces the green color filter 126g and the blue color filter 126b of the image display device 100 in order to realize an image display device that supports a color gamut wider than the NTSC and AdobeRGB color gamuts. A filter 126g ′ and a blue color filter 126b ′ are provided.

  Specifically, in the present embodiment, as the green color filter 126g ′, one having a light transmittance of 10% or less in a wavelength region of 600 nm or more and 680 nm or less and a half width of the transmission spectrum of 90 nm or less is used. ing. Further, as the green color filter 126g ', a filter having a light transmittance of 10% or less in a wavelength region of 470 nm or less can be preferably used.

  In the present embodiment, a blue color filter 126b 'is used that has a light transmittance of 10% or less in a wavelength region of 520 nm or more and 680 nm or less and a half width of a transmission spectrum of 100 nm or less.

  An example of the transmission spectrum of the green color filter 126g 'and the blue color filter 126b' is shown in FIG. In addition, color filters having characteristics such as the green color filter 126g 'and the blue color filter 126b' can be manufactured by a conventionally known method. For example, Patent Document 4 describes the manufacturing method.

(Example of light emitting device)
Next, Example D10 of the light emitting device 10 according to this embodiment will be described with reference to FIG. FIG. 17 shows the mixing ratio of the green phosphor 13 and the red phosphor 12 dispersed in the dispersion material 16 of the light emitting device 10 according to Example D10, and the dispersion material 16, the green phosphor 13, and the red phosphor 12. It is a table | surface which shows the mixing ratio.

  The light emitting device 10 according to Example D10 is similar to Example D4 except that the weight ratio between the red phosphor 12 and the green phosphor 13 and the weight ratio between the silicone resin and the phosphor are the weight ratios shown in FIG. The light emitting device 10 is manufactured in the same manner. Each weight ratio in Example D10 (mixed amount of the red phosphor 12, the green phosphor 13 and the dispersion material 16) is a white point when transmitted through a liquid crystal panel including a color filter having a transmission spectrum shown in FIG. Is adjusted to be white in the vicinity of 10,000K.

(Example of image display device)
Next, an embodiment DIS10 of the image display apparatus 200 will be described with reference to FIG. FIG. 18 is a table showing the coverage, area ratio, and chromaticity coordinates of the image display apparatus 200 according to Example DIS10 of the present embodiment. In FIG. 18, for comparison, the cover rate of the image display apparatus 100 according to Example DIS5 of Embodiment 2 is shown.

  The image display apparatus 200 according to the embodiment DIS10 has a structure shown in FIG. As the backlight, the light emitting device 10 of Example D10 was used. Further, as the blue and green color filters, the blue color filter 126b ′ and the green color filter 126g ′ having the transmittance shown in FIG. 16 are used, and as the red color filter, the red color filter 126r having the transmittance shown in FIG. 10 is used. .

  As shown in FIG. 18, in the image display apparatus 200 according to the embodiment DIS10, the NTSC cover rate and the AbbeRGB cover ratio are substantially the same (maintained) as those of the image display apparatus 100 according to the embodiment DIS5. I understand. On the other hand, in the image display apparatus 200 according to Example DIS10, it can be seen that the NTSC area ratio and the AbbeRGB area ratio are larger than those of the image display apparatus 100 according to Example DIS5. That is, in the image display apparatus 200, it can be seen that the color gamut can be greatly expanded as compared with the image display apparatus 100 according to the second embodiment.

  As described above, the image display apparatus 200 according to this embodiment is the BT. It can be suitably used as an image display device corresponding to the next-generation color gamut such as 2020.

[Embodiment 6]
Embodiment 6 will be described as follows with reference to FIG. FIG. 14 shows the mixing ratio of the green phosphor 13 and the red phosphor 12 dispersed in the dispersion material 16 of the light emitting device 10 according to Example D11 of the present embodiment, and the dispersion material 16 and the green phosphor 13 and It is a table | surface which shows the mixing ratio with the red fluorescent substance 12, and luminous efficiency. Since the light emitting device according to this embodiment is the same as the light emitting device 10 except for the light emitting element 11, the description thereof is omitted.

  In the light emitting device according to the present embodiment, the peak wavelength of the primary light (excitation light) emitted from the light emitting element is not less than 440 nm and not more than 460 nm. Even with such a light emitting element that emits primary light (excitation light) of a peak wavelength, it is possible to provide a light emitting device that can realize an image display device with a wide color reproduction range.

(Relationship between peak wavelength of primary light and luminous efficiency)
As shown in FIG. 14, in Example D11 of this embodiment, the peak wavelength of the primary light (excitation light) emitted from the light emitting element 11 is 460 nm. Further, as in Example D5, the green phosphor 13 manufactured in Production Example P5 is used, and the red phosphor 12 and the green phosphor 13 are dispersed 16 in a mixing ratio as shown in FIG. Are distributed. Further, the mixing amount of the red phosphor 12, the green phosphor 13 and the dispersion material 16 in Example D11 is the same as in Examples D1 to D5 and D7 described above, but the liquid crystal panel including the color filter having the transmission spectrum shown in FIG. When transmitted, the chromaticity point indicating the white point is adjusted to be white at a color temperature of 10,000 K near (CIEx, CIEy) = (0.281, 0.288).

  As shown in FIG. 14, the luminous efficiency of Example D11 (peak wavelength of light emitting element 11: 460 nm) is 88 when the luminous efficiency of Example D5 (peak wavelength of light emitting element 11: 445 nm) is 100. . Thus, the luminous efficiency of Example D11 is lower than the luminous efficiency of Example D5 as described above. However, it can be said that the luminous efficiency of Example D11 is such that the desired luminous efficiency that can be achieved in the image display device of the present application can be achieved.

  Further, as described in Embodiment 4, the light emission efficiency of Example D9 (peak wavelength of light emitting element 11: 440 nm) is 96 when the light emission efficiency of Example D5 is 100. Thus, it can be said that the luminous efficiency of Example D9 has realized the luminous efficiency comparable to Example D5.

  From the result of FIG. 14, when the peak wavelength of the primary light emitted from the light emitting element 11 is 440 nm or more and 460 nm or less, predetermined light emission efficiency can be realized. Therefore, the light emitting device 10 according to this embodiment can be suitably used for the image display device of the present application.

[Summary]
The light emitting device (10, 10a) according to the first aspect of the present invention includes a light emitting element (11) that emits blue light, and a Mn ²⁺ activated γ-AlON phosphor that emits green light when excited by the blue light (green phosphor). 13) and Mn ⁴⁺ activated phosphor (red phosphor 12) that emits red light when excited by the blue light, and includes Mn 2 ⁺ -activated γ-AlON phosphor contained in the crystal. The concentration is 1.5 wt% or more and 4.5 wt% or less.

According to the above configuration, the Mn ²⁺ activated γ-AlON phosphor as a green phosphor that emits green light when excited by blue light, and the Mn ⁴⁺ activation as a red phosphor that emits red light when excited by blue light. A wavelength conversion member is formed by combining with a phosphor. And the density | concentration of Mn contained in the crystal | crystallization of Mn2 ⁺ activated γ-AlON fluorescent substance is 1.5 wt% or more and 4.5 wt% or less.

In a light emitting device that excites Mn ²⁺ activated γ-AlON phosphor and Mn ⁴⁺ activated phosphor with blue light, if the Mn concentration is less than 1.5 wt% and greater than 4.5 wt%, NTSC The color reproducibility of the image display device is deteriorated, for example, the coverage of the color gamut and AdobeRGB color gamut deteriorates. That is, when the Mn concentration is 1.5 wt% or more and 4.5 wt% or less, the coverage ratio for the NTSC color gamut and AdobeRGB color gamut can be increased.

  Therefore, according to the light emitting device according to the above aspect, there is an effect that an image display device having a wide color reproduction range can be realized.

Further, according to the above configuration, in the excitation spectrum of the Mn ²⁺ activated γ-AlON phosphor, the half-value width of the peak wavelength near 445 nm widens, so even if the peak wavelength of blue light fluctuates, the excitation light of the phosphor The rate is unlikely to fluctuate. Therefore, according to the light emitting device according to the above-described aspect, there is an effect that it is possible to realize an image display device with little variation in the color gamut (color variation).

Furthermore, according to the above configuration, since Mn is contained in the Mn ²⁺ activated γ-AlON phosphor by 1.5 wt% or more, the absorption ratio of blue light (excitation light) of the Mn ²⁺ activated γ-AlON phosphor is increased. Can be improved. Thus, the light emission efficiency of the light emitting device according to the above embodiment can be improved.

In the light emitting device according to aspect 2 of the present invention, in aspect 1, the half width of the emission spectrum of green light emitted from the Mn ²⁺ activated γ-AlON phosphor is preferably 35 nm or more and 50 nm or less.

According to said structure, when the half value width of the emission spectrum of Mn2 ⁺ activation | activation gamma-AlON fluorescent substance is less than 35 nm, the density | concentration of said Mn is less than 1.5 wt%. Moreover, when the half value width of the emission spectrum of the Mn ²⁺ activated γ-AlON phosphor exceeds 50 nm, the Mn concentration exceeds 4.5 wt%. In this case, the coverage with respect to the NTSC color gamut and the AdobeRGB color gamut deteriorates. That is, when the half-value width of the emission spectrum of green light is 35 nm or more and 50 nm or less, the coverage with respect to the NTSC color gamut and AdobeRGB color gamut can be increased.

  Therefore, according to the light emitting device according to the above aspect, an image display device having a wide color reproduction range can be realized.

In the light emitting device according to aspect 3 of the present invention, in the aspect 1 or 2, the Mn ²⁺ activated γ-AlON phosphor preferably contains Mg.

According to said structure, when Mg is contained in the Mn2 ⁺ activated γ-AlON phosphor, the crystal structure of the γ-AlON crystal is stabilized. Therefore, Mn can be easily taken into the phosphor. Therefore, it is possible to easily increase the Mn concentration in the Mn ²⁺ activated γ-AlON phosphor, so that the light emission efficiency of the light emitting device according to the above embodiment can be improved.

In the light emitting device according to aspect 4 of the present invention, in any one of aspects 1 to 3, the Mn ⁴⁺ activated phosphor is preferably a Mn ⁴⁺ activated fluorine complex phosphor.

According to said structure, the half value width of the emission spectrum of the red light which ^{Mn4 +} activation fluorine complex fluorescent substance emits is narrow, and the excitation efficiency of blue light is high. Therefore, the light emission efficiency of the light emitting device according to the above embodiment can be improved. In addition, since the color reproduction range can be expanded to the red side, a light emitting device having excellent red color reproduction can be realized.

In the light emitting device according to aspect 5 of the present invention, in the aspect 4, the Mn ⁴⁺ activated fluorine complex phosphor is K ₂ (Ti _1-h Mn _h ) F ₆ or K ₂ (Si _1-h Mn _h ) F _6. And h is preferably 0.001 or more and 0.1 or less.

According to the above configuration, ^{Mn 4+} activated fluorine complex phosphor is _{K 2 (Ti 1-h Mn} h) F 6 or _{K 2 (Si 1-h Mn} h) F 6, h is 0.001 or more and When it is 0.1 or less, the emission intensity of the Mn ⁴⁺ activated fluorine complex phosphor is high, and the stability of the phosphor crystal is high. Therefore, the light emission efficiency and reliability of the light-emitting device according to the above embodiment can be improved.

In the light emitting device according to aspect 6 of the present invention, in the aspect 4 or 5, the Mn ⁴⁺ activated fluorine complex phosphor is preferably a Mn ⁴⁺ activated K ₂ SiF ₆ phosphor.

According to the above configuration, ^{Mn 4+} activated _K 2 SiF ₆ phosphors, stability (water resistance) is high. Therefore, the reliability of the light-emitting device according to the above embodiment can be improved.

  In the light emitting device according to aspect 7 of the present invention, in any one of aspects 1 to 6, the peak wavelength of the blue light is preferably 440 nm or more and 460 nm or less.

According to the above configuration, the excitation efficiency of the Mn ²⁺ activated γ-AlON phosphor and the Mn ⁴⁺ activated phosphor can be increased. Further, the wavelength matching with the blue color filter that transmits blue light is good. Therefore, the light emission efficiency of the light emitting device can be improved. In addition, the luminance (display brightness) of the image display device including the light-emitting device can be improved.

The light-emitting device (10a) according to the eighth aspect of the present invention is the light-emitting device (10a) according to any one of the first to seventh aspects, wherein the Mn2 ⁺ activated γ-AlON phosphor and the Mn4 ⁺ activated phosphor are in a common dispersion material (16). It is preferable that the dispersion material includes a scattering material (light scattering material 17) that scatters the blue light emitted from the light emitting element.

According to said structure, the scattering material which scatters the blue light (excitation light) emitted from the light emitting element is contained in the dispersion material by which Mn2 ⁺ activated (gamma) -AlON fluorescent substance and Mn4 ⁺ activated fluorescent substance are disperse ^| distributed. ing. Therefore, it is possible to more efficiently irradiate the Mn ²⁺ activated γ-AlON phosphor and the Mn ⁴⁺ activated phosphor with the blue light scattered by the scattering material. Therefore, the amount of Mn ²⁺ activated γ-AlON phosphor and Mn ⁴⁺ activated phosphor used can be reduced. In addition, the light emission efficiency of the light emitting device can be improved.

  The image display device (100, 200) according to the ninth aspect of the present invention preferably includes any one of the light-emitting devices according to the first to eighth aspects.

  According to said structure, there exists an effect that an image display apparatus with a wide color reproduction range is realizable.

  The image display device (100) according to the tenth aspect of the present invention includes the green color filter (126g) that transmits green light in the ninth aspect, and transmits the light in the wavelength range of 520 nm to 540 nm of the green color filter. The rate may be 80% or more.

According to said structure, the transmittance | permeability of the light of the wavelength range of 520 nm or more and 540 nm or less of a green color filter is 80% or more. In the light emitting device, since the Mn ²⁺ activated γ-AlON phosphor is used as the green phosphor, the color gamut of the image display device can be increased even when the green color filter having such a high transmittance is used. Can be wide. In addition, since a green color filter with high transmittance can be used, the luminance of the image display device can be improved.

  An image display device (200) according to an aspect 11 of the present invention includes the green color filter (126g ′) that transmits green light and the blue color filter (126b ′) that transmits blue light in the aspect 9, The green color filter has a light transmittance of 10% or less in the wavelength region of 600 nm or more and 680 nm or less, and the half width of the transmission spectrum of the green color filter is 90 nm or less, and the blue color filter has a wavelength of 520 nm or more. The transmittance of light in the wavelength region of 680 nm or less is preferably 10% or less, and the half width of the transmission spectrum of the blue color filter is preferably 100 nm or less.

  According to said structure, the color reproduction range of an image display apparatus can be further expanded.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

10, 10a Light emitting device 11 Light emitting element 12 Red phosphor (Mn ⁴⁺ activated phosphor, Mn ⁴⁺ activated fluorine complex phosphor, Mn ⁴⁺ activated K ₂ SiF ₆ phosphor)
13 Green phosphor (Mn ²⁺ activated γ-AlON phosphor)
16 Dispersant 17 Light scattering material (scattering material)
100, 200 Image display device 126b 'Blue color filter 126g, 126g' Green color filter

Claims (11)

A light emitting element emitting blue light;
A Mn ²⁺ activated γ-AlON phosphor that emits green light when excited by the blue light;
A Mn ⁴⁺ activated phosphor that emits red light when excited by the blue light, and
The light-emitting device, wherein the concentration of Mn contained in the crystal of the Mn ²⁺ activated γ-AlON phosphor is 1.5 wt% or more and 4.5 wt% or less. 2. The light emitting device according to claim 1, wherein a half width of an emission spectrum of green light emitted by the Mn ²⁺ activated γ-AlON phosphor is 35 nm or more and 50 nm or less. The light emitting device according to claim 1 or 2, wherein the Mn ²⁺ activated γ-AlON phosphor contains Mg. ^4. The light emitting device according to claim 1, wherein the Mn ⁴⁺ activated phosphor is a Mn ⁴⁺ activated fluorine complex phosphor. 5. The Mn ⁴⁺ activated fluorine complex phosphor is K ₂ (Ti _1-h Mn _h ) F ₆ or K ₂ (Si _1-h Mn _h ) F ₆ , and h is 0.001 or more and 0.1 or less. The light emitting device according to claim 4, wherein the light emitting device is provided. _6. The light emitting device according to claim 4, wherein the Mn ⁴⁺ activated fluorine complex phosphor is a Mn ⁴⁺ activated K ₂ SiF ₆ phosphor.   7. The light emitting device according to claim 1, wherein a peak wavelength of the blue light is not less than 440 nm and not more than 460 nm. The Mn ²⁺ activated γ-AlON phosphor and the Mn ⁴⁺ activated phosphor are dispersed in a common dispersion material,
The light-emitting device according to claim 1, wherein the dispersion material includes a scattering material that scatters blue light emitted from the light-emitting element.   An image display device comprising the light-emitting device according to claim 1. With a green color filter that transmits green light,
The image display device according to claim 9, wherein the green color filter has a light transmittance of 80% or more in a wavelength region of 520 nm or more and 540 nm or less. A green color filter that transmits green light and a blue color filter that transmits blue light;
The green color filter has a light transmittance of 10% or less in the wavelength region of 600 nm or more and 680 nm or less, and the half width of the transmission spectrum of the green color filter is 90 nm or less.
The blue color filter has a light transmittance of 10% or less in a wavelength region of 520 nm or more and 680 nm or less, and a half width of a transmission spectrum of the blue color filter is 100 nm or less. The image display device described.