JP2007059898A - Semiconductor light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor light-emitting device in which chromaticity variation is reduced and a red color rendering property is improved. <P>SOLUTION: The semiconductor light-emitting device is characterized by: a semiconductor light-emitting element that emits first-wavelength light; a first phosphor that absorbs the first-wavelength light and emits second-wavelength light having a wavelength longer than that of the first-wavelength light; and a second phosphor that absorbs the first-wavelength light and emits third-wavelength light having a wavelength longer than that of the second-wavelength light; wherein the first phosphor and the second phosphor are expressed by a common chemical composition formula and the first-wavelength light, the second-wavelength light and the third-wavelength light yield mixed-colored light emission. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor light emitting device, and more particularly to a semiconductor light emitting device that performs wavelength conversion by exciting a phosphor with emitted light from a semiconductor light emitting element.

  In recent years, semiconductor light-emitting devices have come to be widely used as light sources for lighting and display devices. In particular, with the realization of blue light-emitting elements (blue LEDs) using gallium nitride (GaN) -based materials, the use of white light-emitting semiconductor light-emitting devices has dramatically expanded.

A white light emitting semiconductor light emitting device includes a gallium nitride light emitting element having a wavelength range of ultraviolet to blue and a phosphor that emits light having a longer wavelength excited by absorbing the emitted light. For example, white light is synthesized by mixing radiated light from a blue light emitting element and yellow light from a yellow phosphor that converts blue light into yellow at a predetermined ratio. In this case, as an example of the yellow phosphor, there is a silicate phosphor (Me _1-y Eu _y ) ₂ SiO ₄ (Me is at least one metal element selected from Ba, Sr, Ca, and Mg).

In this configuration, since there is little red component, the color rendering property of red is lacking. However, in applications such as lighting, there is a strong tendency to prefer “warm color”, that is, “bulb color”. For this reason, there is a disclosed example in which red color rendering is improved by using a red phosphor made of oxynitride (Patent Document 1). However, the composition of the oxynitride phosphor is physically and chemically different from the composition of the yellow phosphor. As a result, it is not easy for the two phosphors to be uniformly dispersed in the sealing resin, and chromaticity variation, that is, “color unevenness” occurs in a mass-produced product. Also, the reproducibility of the manufacturing process is insufficient. As a result, the characteristics are insufficient for applications such as illumination and light sources of display devices.
JP 2005-112922 A

  The present invention provides a semiconductor light emitting device with reduced chromaticity variation and improved red color rendering.

According to one aspect of the invention,
A semiconductor light emitting device emitting first wavelength light;
A first phosphor that absorbs the first wavelength light and emits a second wavelength light having a longer wavelength than the first wavelength light;
A second phosphor that absorbs the first wavelength light and emits third wavelength light having a longer wavelength than the second wavelength light;
With
The first phosphor and the second phosphor are represented by a common chemical composition formula,
There is provided a semiconductor light emitting device characterized in that the first wavelength light, the second wavelength light, and the third wavelength light generate mixed color light emission.

  According to the present invention, there is provided a phosphor wavelength conversion type semiconductor light emitting device with reduced chromaticity variation and improved red color rendering.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing a semiconductor light emitting device 60 according to a first specific example of the present invention.
The semiconductor light emitting device 60 has a structure in which the blue semiconductor light emitting element 10 is bonded to a thick inner lead 402 constituting the first lead 40 with a silver paste 13 or the like. The inner lead 402 is provided with a first recess 19, and the semiconductor light emitting element 10 is bonded to the bottom surface of the first recess 19.

  An electrode (not shown) provided on the upper surface of the semiconductor light emitting element 10 and the second lead 44 are connected by a bonding wire 25. This structure belongs to a so-called SMD (Surface Mounting Device) type semiconductor light emitting device.

  The first lead 40 and the second lead 44 made of metal are embedded with, for example, a thermoplastic resin 42 or the like. The inner lead 402 is thicker than the outer lead 404 and has a heat sink function for the semiconductor light emitting element 10. A second recess 50 is provided on the upper portion of the thermoplastic resin 42 so as to be continuous with the first recess 19. An inclined reflector 46 is provided inside the thermoplastic resin 42. The reflector 46 and the inner side surface 20 of the first recess 19 have an action of reflecting upward the radiation light from the semiconductor light emitting element 10 and the light whose wavelength has been converted by the phosphor.

  A sealing resin 23 such as silicone mixed with a phosphor is provided on the first recess 19 provided on the inner lead 402 and the upper portion of the semiconductor light emitting element 10. When the sealing resin 23 has a hemispherical shape or a semi-ellipsoidal shape, a lens function for condensing light can be provided, and directivity can be easily controlled. As illustrated in a partially enlarged manner in FIG. 1, in this specific example, a yellow phosphor 21 made of silicate and an orange phosphor 22 made of silicate are dispersedly arranged in a transparent resin 23. As a result, the emitted light from the blue semiconductor light emitting element 10 is absorbed by the yellow phosphor 21, and the wavelength is converted by excitation to generate yellow light. In addition, blue radiant light from the blue semiconductor light emitting element 10 is absorbed by the orange phosphor 22 and is converted in wavelength by excitation to generate orange light. As a result, it is possible to obtain warm white light, in other words, “bulb color”.

Next, the phosphor will be described in more detail.
In this specific example, (Me _1-y Eu _y ) ₂ SiO ₄ (Me is at least one element selected from Ba, Sr, Ca, Mg, 0 <y ≦ 1). The yellow phosphor 21 and the orange phosphor 22 are constituted by the silicate phosphor to be formed. Ba (barium), Sr (strontium), and Ca (calcium) are called “alkaline earth metals”.

FIG. 2 is a graph showing the wavelength dependence of the excitation spectrum of the yellow phosphor 21 made of silicate used in this example.
The wavelength (unit: nm) from a light source such as the semiconductor light emitting element 10 is represented on the horizontal axis, and the relative excitation intensity from the phosphor is represented on the vertical axis. When the wavelength is in the range of 300 to 490 nanometers, high excitation intensity is obtained by exciting the radiated light from the light source. In this specific example, excitation is performed using the blue semiconductor light emitting element 10 having a wavelength of 450 to 470 nanometers.

FIG. 3 is a graph showing an emission spectrum of the semiconductor light emitting device, in which the vertical axis represents relative emission intensity and the horizontal axis represents emission wavelength (unit: nm).
The “bulb color” of the semiconductor light emitting device 60 according to this specific example by the three-color mixing of the light emission of the blue semiconductor light emitting element 10, the wavelength converted light by the yellow phosphor 21, and the wavelength converted light by the orange phosphor 22 is indicated by a solid line. Represent. The peak of the relative light emission intensity is at 450 nanometers which is the emission center of the emitted light of the blue semiconductor light emitting device 10 and near 580 nanometers wavelength-converted by the phosphor.

  On the other hand, in the first comparative example, white light is obtained by mixing the light emitted from the blue semiconductor light emitting element 10 of about 450 nanometers and the yellow light by the yellow phosphor 21, and this is represented by a broken line. Peaks of emission spectrum intensity are generated around 450 nanometers, which is the wavelength center of the emitted light from the blue semiconductor light emitting element 10, and around 575 nanometers, which is the wavelength center of the wavelength converted light from the yellow phosphor 21. By mixing the two lights, the white light of the first comparative example is obtained.

  In this specific example, since there is the orange phosphor 22, the emission spectrum in the wavelength range of 580 nanometers or more is different from that of the first comparative example. In particular, in the 580 to 700 nanometer wavelength range of part A exemplified by the two-dot chain line in FIG. 3, the relative emission intensity can be made higher than that of the first comparative example. By reinforcing this red spectral component, the red color rendering can be improved as compared with the first comparative example.

  Here, it is assumed that the wavelength light from the blue semiconductor light emitting element 10 has an emission spectrum peak in a wavelength range of 430 nanometers or more and smaller than 490 nanometers. The emission wavelength light from the yellow phosphor has an emission spectrum peak in a wavelength range of 490 nanometers or more and smaller than 580 nanometers. Further, it is assumed that the emission wavelength light from the orange phosphor has an emission spectrum peak in a wavelength range of 580 nm or more and smaller than 620 nm.

Next, a common silicate phosphor represented by (Me _1-y Eu _y ) ₂ SiO ₄ (Me is at least one element selected from Ba, Sr, Ca, Mg, 0 <y ≦ 1) The difference in composition between the yellow phosphor 21 and the orange phosphor 22 represented by the chemical composition formula will be described. Note that Me ₂ SiO ₄ is also called a base material, and Eu (europium) that forms a light emission center is also called an activator.

  As an example of the yellow phosphor 21, in the above chemical composition formula, Sr (strontium) is 1.78, Ba (barium) is 0.12, Eu (europium) is 0.10, Si (silicon) is 1.0, Each composition ratio can be selected such that O (oxygen) is 4.0.

  Further, as an example of the orange phosphor 22, in the above chemical composition formula, Sr is 1.33, Ca is 0.57, Eu is 0.10, Si (silicon) is 1.0, and O (oxygen) is 4. 0 and each composition ratio can be selected. In this way, the emission spectrum can be changed by changing the composition ratio of Ba, Sr, Ca (calcium), and Mg (magnesium) represented by Me. In this case, being expressed by a common chemical composition formula means that the physical and chemical properties are close to each other, and therefore, the contained Me element may not be exactly the same between the two.

Next, the particle size of the phosphor will be described.
Generally, there is a “smashed layer” on the surface of the phosphor. Since the thickness of the crushed layer is determined by the crushing step, the larger the particle size of the phosphor, the lower the volume ratio of the surface crushed layer. As a result, a phosphor having a larger particle size can have higher luminance. For this reason, the lower limit of the phosphor particle size is desirably about 3 micrometers.

On the other hand, the sedimentation rate (v) of the phosphor in the liquid resin is approximately the following among the particle size (d), the phosphor density (ρp), the resin density (ρ), and the resin viscosity (η). (Equation 1) holds.
v = C (ρ _p −ρ) d ² / η (Formula 1)
However, C is a constant.

  As exemplified in (Formula 1), when the particle size of the phosphor increases, the sedimentation rate in the sealing resin increases. Therefore, during the assembly process, the dispersion state of the phosphor changes depending on the time from mixing with the liquid sealing resin to the start of heat curing. In order to reduce this influence, the upper limit of the phosphor particle diameter can be set to 20 micrometers, for example.

  FIG. 4 is a chromaticity diagram according to the CIE (Commission International de I'Eclairage) standard. The curved line portion is a spectral locus with an emission wavelength of 380 to 780 nanometers, and the straight line connecting both end points is a pure purple locus.

  The 450 nanometer radiated light from the blue semiconductor light emitting device 10 is represented by (0.15, 0.03) in the xy coordinates. The wavelength converted light from the yellow phosphor 21 having a peak wavelength of about 575 nanometers is represented by (0.480, 0.505) in the xy coordinates. Further, the wavelength converted light from the orange phosphor 22 having a peak wavelength of about 593 nanometers is represented by (0.498, 0.472) in the xy coordinates. As a result, the chromaticity within the triangle connecting these three points can be realized, and white light near the center is realized by appropriately selecting the blending ratio. A, B, and D65 represent standard light.

  Note that the chromaticity on the straight line M connecting these two points can be realized by the color mixture of the 450 nanometer radiation light from the blue semiconductor light emitting element 10 and the wavelength converted light from the yellow phosphor 21. The first comparative example is obtained in this way. In this case, as shown by the broken line in FIG. 3, the red spectral component is less than in the present specific example, and thus white light lacking red color rendering is obtained and “warmth” is lacking.

  On the other hand, in this specific example, the red spectral component can be reinforced by the orange phosphor 22 and the “warmth” can be increased. Further, as illustrated in FIG. 4, in the chromaticity diagram, mixing within a triangular region is possible, so that an effect of increasing the degree of freedom in color mixing also occurs.

Here, the second comparative example will be described.
In this specific example, an orange phosphor 22 made of a silicate phosphor is used to improve red color rendering. However, it is conceivable to use a nitride phosphor or an oxynitride phosphor to increase the red spectral component. Here, a case where a nitride phosphor is used will be described as a second comparative example.

Examples of the nitride phosphor include Me ₂ Si ₅ N ₈ : Eu (Me is Sr, Ba, Ca), CaSiN ₂ : Eu, and CaAlSiN ₃ : Eu. For example, wavelength conversion light from a red phosphor represented by a chemical composition formula of Me ₂ Si ₅ N ₈ : Eu (Me is Sr, Ba, Ca), 450 nanometer radiation from a blue semiconductor light emitting element, The case where white light is obtained by color mixing with wavelength-converted light from a yellow phosphor made of silicate is taken as a second comparative example.

  FIG. 5 shows a chromaticity diagram in the second comparative example. The wavelength converted light from the red phosphor having a peak wavelength of about 652 nanometers is represented by (0.630, 0.370) in the xy coordinates.

  White light is obtained by mixing the above three colors, but the chemical composition formula of the red phosphor made of nitride or oxynitride is different from the chemical composition formula of the yellow phosphor. Therefore, it differs in terms of physical characteristics such as specific gravity and shape, and other chemical characteristics. As a result, since these two types of phosphors are not uniformly dispersed in the sealing resin, chromaticity variation, that is, “color unevenness” occurs in the product. Also, the reproducibility of the manufacturing process is insufficient.

Next, the comparison result regarding the chromaticity variation caused by the difference in the sedimentation speed of the phosphor, that is, “color unevenness” will be described.
FIG. 6 shows the color in the semiconductor light emitting device 60 having the structure illustrated in FIG. 1 in which the liquid sealing resin, the yellow phosphor 21 and the orange phosphor 22 are mixed and heat-cured after being left for 2 hours. It is the result of measuring the degree variation distribution. FIG. 6 is a partially enlarged view of the range of coordinates x and y of 0.35 to 0.45 in the chromaticity diagram illustrated in FIG. The chromaticity of samples extracted from the product group of the semiconductor light emitting device 60 is represented by white circles. Although x varies within the range of 0.398 to 0.422 and y varies within the range of 0.385 to 0.402, the chromaticity variation range of the sample is small. This is probably because the difference in sedimentation speed between the yellow phosphor 21 and the orange phosphor 22 is small, indicating that these two types of phosphors are well mixed and distributed.

  On the other hand, FIG. 7 shows a semiconductor light emitting device in which a liquid sealing resin, a yellow phosphor, and a red phosphor made of a nitride phosphor are mixed and heat-cured after being left for 2 hours in the second comparative example. It is a chromaticity fluctuation distribution measurement result. This structure is similar to that illustrated in FIG. FIG. 7 also shows a partially enlarged chromaticity diagram, and a black square mark indicates the chromaticity of each sample. As illustrated in the figure, x varies within a range of 0.402 to 0.429, and y varies within a range of 0.371 to 0.395. This variation range is larger than that of the first specific example illustrated in FIG.

The reason is considered as follows. That is, in the second comparative example, since the chemical composition formulas of the yellow phosphor and the red phosphor are different, the shape and specific gravity are different and are not uniformly mixed. As a result, the two types of phosphors have a difference in sedimentation speed, and the sedimentation layer is not uniform.

FIG. 8 is a photograph comparing the sedimentation degree after mixing the liquid sealing resin and the phosphor and leaving them for 96 hours.
In the left sample, which is the second comparative example, the yellow phosphor precipitation layer YE is separated downward and the red phosphor precipitation layer OR is sedimented upward due to the difference in precipitation rate. In FIG. 8, the contrast is slightly difficult to obtain, but when observed with the naked eye, the red phosphor precipitate layer OR is reddish, whereas the yellow phosphor precipitate layer YE appears yellow with almost no redness. In the vicinity of these boundaries, a gradation in which the red component gradually decreases is observed.
On the other hand, in the sample on the right side which is this specific example, since the difference in sedimentation speed is small, the mixed sedimentation layer MI settles in a state where the blending ratio is substantially uniform with respect to the depth direction distance. Even when observing with the naked eye, the entire image appears uniform, and color unevenness cannot be recognized. As a result, the variation in chromaticity is small (that is, “color unevenness” is small), the characteristics can be made uniform, and the reproducibility of the assembly process is also excellent.

  In addition, the red phosphor made of nitride in the second comparative example contains a lot of infrared emission spectrum components. As a result, the conversion efficiency in wavelength conversion decreases. On the other hand, in this specific example, since the infrared emission spectrum component can be reduced, a decrease in conversion efficiency can be suppressed.

Next, characteristics of the semiconductor light emitting device 60 according to this example will be described.
The structure illustrated in FIG. 1 is superior in heat dissipation because the inner lead 402 is thicker than the outer lead 404, and can operate with a larger current.
FIG. 9 is an on-axis luminous intensity-forward current characteristic of the semiconductor light emitting device 60 according to this example (Ta = 25 ° C.). A light output of 6250 mcd is obtained at a forward current of 350 mA. Further, the light is effectively guided upward by the reflector 46 provided on the side surface 20 of the first recess 19 provided in the first lead 40 and the side surface of the second recess 50 provided in the thermoplastic resin 42. Light extraction efficiency can be improved and directivity control is possible.

FIG. 10A is a graph showing the directivity characteristics of the semiconductor light emitting device 60 according to this example. FIG. 10B is a schematic plan view of the semiconductor light emitting device 60 of this example.
In the cross section along one center line AA ′ of the semiconductor light emitting device 10 bonded to the semiconductor light emitting device 60, the angle of the emitted light emission intensity upward from the semiconductor light emitting device 10 and the vertical axis is changed. Then, the directivity as shown in FIG. 10A can be obtained. The luminous intensity relative value of the emitted light is represented by the radial coordinate. In this structure, the maximum value on the vertical optical axis of the semiconductor light emitting device 10 is the maximum, and the relative value of the luminous intensity is “1”.

  The angle at which the relative luminous intensity is one half of the maximum value is referred to as a full width at half maximum θ. In this specific example, the full width at half maximum θ is 40 degrees, and a sharp directivity is obtained. This is because the sealing resin 23 has a condensing lens function as illustrated in FIG. Further, the full width at half maximum θ can be controlled by the shape and the inclination angle of the reflector 46 in the side surface 20 of the first recess 19 and the second recess 50.

  Such a high output property and high controllability of directivity in the first specific example enables the semiconductor light emitting device 60 suitable for lighting applications with long life and easy maintenance. For example, spot lighting in airplanes, automobiles, trains, and the like can be used in a wide range of applications utilizing features such as small size, light weight, ease of maintenance, and long life. Further, since the red color rendering is improved, “warm” white light is obtained, which is more suitable for the above-mentioned use.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these. For example, the wavelength of the semiconductor light emitting element radiation is 450 nanometers or less, and may include, for example, an ultraviolet light region.

Further, three or more kinds of phosphors represented by a common chemical composition formula may be included.
FIG. 11 is a chromaticity diagram of a semiconductor light emitting device according to a second specific example including three types of silicate phosphors. The radiated light from the blue semiconductor light emitting element is represented by (0.155, 0.026) in the xy coordinates. Wavelength converted light from a yellow phosphor made of silicate is expressed by xy coordinates (0.431, 0.545). Similarly, wavelength-converted light from an orange phosphor made of silicate is represented by xy coordinates (0.498, 0.472), and wavelength-converted light from a yellow-green phosphor made of silicate is (0 .221, 0.615). By mixing the light represented by such coordinates, white light with more excellent color rendering can be obtained.

Furthermore, the phosphor is not limited to a silicate phosphor.
FIG. 12 is a chromaticity diagram of a semiconductor light emitting device according to a third specific example including three types of nitride phosphors represented by a common chemical composition formula. The radiated light from the blue semiconductor light emitting element is expressed by xy coordinates (0.155, 0.026). The wavelength-converted light from the yellow phosphor made of nitride is expressed by xy coordinates (0.510, 0.480). Similarly, wavelength-converted light from a yellow-green phosphor made of nitride has an xy coordinate of (0.335, 0.640), and wavelength-converted light from a red phosphor made of nitride has (0.678, 0.318) xy coordinates. By mixing the light represented by such coordinates, white light with more excellent color rendering can be obtained.

FIG. 13 is a chromaticity diagram of a semiconductor light emitting device 60 according to a fourth specific example provided with two types of nitride phosphors. The 470-nanometer radiation emitted from the blue semiconductor light emitting element 10 is represented by xy coordinates (0.100, 0.130). Here, the chemical composition formula of the nitride phosphor is (Me _1−z Eu _z ) ₂ Si ₅ N ₈ (0 <z ≦ 1, Me is at least one element selected from Sr, Ba, Ca, and Mg). I will represent it. When the yellow phosphor 21 has a composition of (Ba _0.93 Eu _0.07 ) ₂ Si ₅ N ₈ , its peak wavelength is in the vicinity of 578 nanometers, and the wavelength conversion light has an xy coordinate of (0.500, 0.480). It is represented by Further, when the orange phosphor 22 has a composition of (Ba _0.8 Eu _0.2 ) ₂ Si ₅ N ₈ , its peak wavelength is in the vicinity of 610 nanometers, and the wavelength converted light is (0.570, 0.405) xy Expressed in coordinates. White light can be obtained by mixing light expressed by such coordinates.
FIG. 14 is a graph comparing the emission spectrum of the fourth specific example with that of the first comparative example. As represented by the solid line, in the fourth specific example, the relative emission intensity can be made higher than that in the first comparative example in the A portion that is in the wavelength range of 580 to 700 nanometers. By such reinforcement of the red spectrum, red color rendering can be improved as compared with the first comparative example.

  FIG. 15 shows the result of measuring the chromaticity variation distribution in the semiconductor light emitting device 60 in which the yellow phosphor 21 and the orange phosphor 22 are mixed with the liquid sealing resin and heat-cured by the same method as in the first specific example. The variation range of 10 samples is smaller than that of the second comparative example in which two kinds of phosphors having different chemical composition formulas are mixed. This indicates that the yellow phosphor 21 and the orange phosphor 22 have a small difference in sedimentation velocity and are well mixed and dispersed.

The phosphor may be a YAG phosphor represented by a chemical composition formula of (Y, Gd) ₃ Al ₅ O ₁₂ : Ce.
FIG. 16 is a chromaticity diagram of a semiconductor light emitting device 60 according to a fifth example having two types of YAG phosphors. The 470-nanometer radiation emitted from the blue semiconductor light emitting element 10 is represented by xy coordinates (0.100, 0.130). When the yellow phosphor 21 has a composition of (Y _0.4 Gd _0.6 ) ₃ Al ₅ O ₁₂ : Ce, its peak wavelength is in the vicinity of 578 nanometers, and the wavelength converted light has an xy coordinate of (0.500, 480). expressed. Further, when the orange phosphor 22 has a composition of (Y _0.2 Gd _0.8 ) ₃ Al ₅ O ₁₂ : Ce, the peak wavelength is around 600 nanometers, and the wavelength converted light is (0.570, 0.410). It is expressed by xy coordinates. White light can be obtained by mixing light expressed by such coordinates.
FIG. 17 is a graph comparing the emission spectrum of the fifth specific example with that of the first comparative example. By using a YAG phosphor, the half-width of the spectrum spreads by about 10 nanometers on the long wavelength side. In the fifth specific example, the red color rendering can be improved as compared with the first comparative example.

FIG. 18 shows the result of measuring the chromaticity variation distribution in the semiconductor light emitting device 60. The variation range of 10 samples is smaller than that of the second comparative example. This indicates that also in the YAG phosphor, the yellow phosphor 21 and the orange phosphor 22 are well mixed and dispersed in the resin. The YAG phosphor may have a chemical composition formula of (Y _u Gd _1-u ) ₃ (Al _w Ga _1-w ) ₅ O ₁₂ : Ce (0 <u ≦ 1, 0 <w ≦ 1). good.

  In addition, a person skilled in the art may make various design changes regarding the shape, size, material, arrangement relationship, etc. of each element such as a semiconductor light emitting element, a lead, a phosphor, and a sealing resin constituting the semiconductor light emitting device. As long as it has the gist of the present invention, it is included in the scope of the present invention.

It is a schematic cross section showing the semiconductor light-emitting device concerning the 1st example of the present invention. It is a graph showing the excitation spectrum of the yellow fluorescent substance concerning the specific example of this invention. It is the graph which contrasted the emission spectrum of the semiconductor light-emitting device concerning the example of this invention with the emission spectrum of the 1st comparative example. It is a chromaticity diagram of the semiconductor light emitting device according to the first specific example of the present invention. It is a chromaticity diagram of the second comparative example. It is a chromaticity diagram showing chromaticity variation distribution in the product of the 1st example. It is a chromaticity diagram showing chromaticity variation distribution in the 2nd comparative example. It is a photograph figure showing the contrast with the 1st specific example and 2nd comparative example regarding the sedimentation degree in liquid sealing resin. It is a graph showing the axial luminous intensity-forward current characteristic of the semiconductor light-emitting device concerning the 1st specific example of this invention. (A) is a graph showing the vertical in-plane directivity of the semiconductor light emitting device according to the first specific example of the present invention, and (b) is a schematic plan view showing a directivity measurement cross section. It is a chromaticity diagram of the semiconductor light emitting device according to the second specific example of the present invention. It is a chromaticity diagram of the semiconductor light-emitting device concerning the 3rd example of the present invention. It is a chromaticity diagram of the semiconductor light-emitting device concerning the 4th example of the present invention. It is a graph showing the emission spectrum of the semiconductor light-emitting device concerning the 4th example. It is a chromaticity diagram showing chromaticity variation distribution in the product of the 4th example. It is a chromaticity diagram of the semiconductor light emitting device according to the fifth specific example of the present invention. It is a graph showing the emission spectrum of the semiconductor light-emitting device concerning the 5th example. It is a chromaticity diagram showing chromaticity variation distribution in the product of the 5th example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Semiconductor light emitting element, 13 Silver paste, 19 1st recessed part, 20 Side surface, 21 Yellow fluorescent substance, 22 Orange fluorescent substance, 23 Sealing resin, 25 Bonding wire, 40 1st lead | read | reed, 42 Thermoplastic resin, 44 2nd lead | read | reed , 46 reflector, 50 second recess, 60 semiconductor light emitting device, 402 inner lead, 404 outer lead

Claims (5)

A semiconductor light emitting device emitting first wavelength light;
A first phosphor that absorbs the first wavelength light and emits a second wavelength light having a longer wavelength than the first wavelength light;
A second phosphor that absorbs the first wavelength light and emits third wavelength light having a longer wavelength than the second wavelength light;
With
The first phosphor and the second phosphor are represented by a common chemical composition formula,
A semiconductor light emitting device, wherein the first wavelength light, the second wavelength light, and the third wavelength light emit light of a mixed color.   The first phosphor and the second phosphor are both silicate phosphors, both nitride phosphors, or both YAG phosphors. The semiconductor light emitting device according to claim 1. The light emitting layer of the semiconductor light emitting element is made of In _x Ga _y Al _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, x + y ≦ 1),
Both the first phosphor and the second phosphor are (Me _1-y Eu _y ) ₂ SiO ₄ (Me is at least one element selected from Ba, Sr, Ca, Mg, 0 <y ≦ 1) and the composition ratios y are different from each other,
2. The semiconductor light emitting device according to claim 1, wherein the light emission of the mixed color is white light. Each of the first phosphor and the second phosphor is made of (Me _1-y Eu _y ) ₂ SiO ₄ (0 <y ≦ 1), and (Me _1-y Eu _y ) ₂ SiO ₄ (0 < 4. The semiconductor light emitting device according to claim 1, comprising: y ≦ 1) and containing both Sr and Ba as elements represented by Me. 5. The first wavelength light has an emission spectrum peak in a wavelength range of 430 nanometers or more and smaller than 490 nanometers,
The second wavelength light has an emission spectrum peak in a wavelength range of 490 nanometers or more and smaller than 580 nanometers,
5. The semiconductor light emitting device according to claim 1, wherein the third wavelength light has an emission spectrum peak in a wavelength range of 580 nanometers or more and smaller than 620 nanometers.