JP2015008335A - Light emitting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly efficient light emitting device having high color rendering properties, which minimizes a decrease in luminous efficiency in a state where a general color rendering index Ra and a special color rendering index R9 are kept at high values, and which can be used for use as general lighting.SOLUTION: A light emitting device comprises: at least one light emitting element 6 which emits light having a peak emission wavelength in a near-ultraviolet or blue region; a green phosphor which is excited by primary light emitted from the light emitting element 6 and emits light having a peak emission wavelength in a green region; a first red phosphor which is excited by the primary light and has a peak emission wavelength in a red region; a second red phosphor which is excited by the primary light and has a peak emission wavelength different from that of the first red phosphor in the red region; and a domal phosphor layer 5 formed by injection of a transparent resin obtained by mixture of three kinds of phosphors such as the green phosphor, the first red phosphor and the second red phosphor on an opening 20 of a liquid-repellent layer 21, for encapsulating the light emitting element 6.

Description

  The present invention relates to a light-emitting device that can be used for a light fixture, a light source of a display device, and the like, and more particularly, to a light-emitting device that can achieve high color rendering while maintaining or suppressing light emission luminance to a minimum.

  Various semiconductor light emitting devices such as lighting devices using semiconductor light emitting elements (hereinafter referred to as “light emitting elements” as appropriate) have been developed, and various means for improving output performance have been studied. In particular, in a light-emitting device that can be used for general lighting equipment, it is important to have high color rendering properties (basically, the average color rendering index Ra is 80 or more, US Energy Star standard, etc.).

  As a typical method for realizing white light emission in a semiconductor light emitting device, first, a method using three types of LED (light emitting diode) chips that emit red, green, and blue light, and second, a blue LED chip. And a method of combining yellow or orange phosphors, third, a method of combining blue LED chips, green phosphors and red phosphors, and fourth, ultraviolet light emitting LED chips, blue phosphors, green phosphors and red A method of combining phosphors is mentioned. Of these, generally, the second or third method is widely used.

  As the structure of the LED light emitting device to which the above-described method is applied, the LED chip is mounted on the cup portion (recessed portion) of the wiring board, and the transparent sealing resin mixed with the phosphor is poured into the cup portion and cured to phosphor. A structure in which a resin layer containing is formed is common (see, for example, Patent Document 1 and Patent Document 2 below).

  In the light emitting device disclosed in Patent Document 1, a blue LED chip is used as a light emitting element, and a total of three types of phosphors of two types of yellow phosphors and red phosphors having different peak emission wavelengths are mixed and dispersed in a transparent resin. Thus, a phosphor layer is formed. In particular, the two types of yellow phosphors are a first yellow phosphor having a peak emission wavelength of 540 ± 20 nm and a first emission wavelength longer than the peak emission wavelength of the first yellow phosphor and having a peak emission wavelength of 590 nm or less. By adjusting the blending ratio of the red phosphors with the yellow phosphor of No. 2, it is possible to suppress a decrease in light emission luminance as much as possible, and to realize relatively high color rendering properties and high light emission luminance at the same time.

  In the light emitting device disclosed in Patent Document 2, deep red light emission is realized by increasing the peak emission wavelength by adding Al and B to the nitride phosphor constituting the red phosphor, and other phosphors ( For example, a phosphor layer is configured in combination with a green phosphor, a yellow phosphor, etc., to realize white light emission.

JP 2007-116117 A International Publication No. 2006-077740

  However, the configuration of the phosphor layer disclosed in Patent Document 1 is a combination of blue light emission from the LED and yellow and red light emission from the phosphor layer, and less color emission in the green region. However, there is a problem that the color rendering index (Ri: i = 1 to 15) is biased.

  Further, in order to improve the average color rendering index Ra and particularly the special color rendering index R9 (red), it is necessary to include a red phosphor having a peak emission wavelength in a relatively long wavelength region (630 nm or more). However, the efficiency of red phosphors is that when the peak emission wavelength is shifted to the long wavelength region, the efficiency of the phosphor itself is drastically reduced due to the effect of human relative visibility. There was a problem of causing. There are several indicators of luminous efficiency, but what is usually used is the luminous efficiency (unit: lm / W) with respect to the input power, and the same applies to the present specification. The specific luminous efficiency is internationally defined as the standard luminous efficiency curve of the CIE (International Commission on Illumination), and is defined as the spectral luminous efficiency in the Ministry of Economy, Trade and Industry Ordinance No. 189 Measurement Unit Regulations Appendix 8 in Japan. In other words, the effect of human visual acuity is that humans feel the strongest light near 555 nm in a bright place and the strongest light near 507 nm in a dark place. Means that the sensitivity is lowered with respect to light that is longer or shorter, and it is felt darker. The luminous efficiency in the case of red color decreases as the wavelength increases.

  Further, in the light emitting device disclosed in Patent Document 2, a plurality of embodiments are disclosed regarding a specific method of realizing a red phosphor that realizes deep red and a light emitting device that combines the red phosphor and another phosphor. However, in order to achieve high color rendering in the same combination of phosphors, there is no disclosure of an index as to what phosphor should be adjusted and what mixing ratio.

  The present invention has been made in view of the above problems, and its purpose is to suppress the decrease in luminous efficiency as much as possible while maintaining the average color rendering index Ra and the special color rendering index R9 at high values. An object of the present invention is to provide a high color rendering and high efficiency light emitting device that can be used in general lighting applications.

  In order to achieve the above object, a light emitting device comprising an LED having a peak emission wavelength in the near-ultraviolet to blue region and a phosphor layer containing a green phosphor and a red phosphor, as a result of diligent research by the present inventors. As a red phosphor, a red phosphor having a peak emission wavelength in the short wavelength region that is close to the peak of specific luminous sensitivity and greatly contributes to maintaining or improving the emission intensity, and a long wavelength that greatly contributes to improving color rendering It was found that the color rendering properties and the emission intensity can be controlled by using two types of red phosphors having a peak emission wavelength in the region and adjusting the blending ratio.

  That is, in order to achieve the above object, the present invention provides at least one light emitting element that emits light having a peak emission wavelength in the near ultraviolet to blue region, and the green region excited by the primary light emitted from the light emitting device. A green phosphor that emits light having a peak emission wavelength, a first red phosphor that is excited by the primary light and emits light having a peak emission wavelength in the red region, and a red region excited by the primary light. And a phosphor layer containing a second red phosphor that emits light having a peak emission wavelength different from that of the first red phosphor.

  Furthermore, in the light emitting device having the above characteristics, a peak emission wavelength of the green phosphor is in a wavelength range of 510 nm or more and 550 nm or less, and a peak emission wavelength of the first red phosphor is in a wavelength range of 610 nm or more and less than 625 nm. Preferably, the second red phosphor has a peak emission wavelength in a wavelength range of 625 nm to 670 nm, and the light emitting element has a peak emission wavelength in a wavelength range of 350 nm to 490 nm. LED chips that emit light are preferred.

  Furthermore, the light emitting element is preferably an LED chip that emits light having a peak emission wavelength within a wavelength range of 430 nm or more and 490 nm or less. Alternatively, the light-emitting element is an LED chip that emits light having a peak emission wavelength in a wavelength range of 350 nm or more and less than 430 nm, and the phosphor layer is excited by primary light emitted from the light-emitting element, It is preferable to further contain a blue phosphor that emits light having a peak emission wavelength within a wavelength range of 430 nm to 490 nm.

Furthermore, in the light emitting device having the above characteristics, the LED chip is preferably an InGaN-based LED chip, and the green phosphor is an Al ₅ Lu _x O _y : Ce phosphor, Ca ₃ (Sc, Mg) _2. It is preferable to include any one of Si ₃ O ₁₂ : Ce phosphor and Al ₅ O ₁₂ Y ₃ : Ce phosphor, and each of the first and second red phosphors may include ( Sr, Ca) AlSiN ₃ : Eu-based phosphors or CaAlSiN ₃ : Eu-based phosphors are preferable.

  According to the light emitting device having the above characteristics, the light emission spectrum of the red component can be obtained by using two types of red phosphors as well as the light emission spectra of all three light components of blue, green, and red. Since the bandwidth can be increased, high color rendering can be realized. When the emission spectrum of red shifts to the longer wavelength side, the luminous efficiency decreases. Therefore, if high color rendering properties are to be realized with one type of red phosphor, the luminous efficiency is greatly reduced. By using two types, it is possible to realize high color rendering properties while maintaining the luminous efficiency.

  Further, in the light emitting device having the above characteristics, it is preferable that the respective weight distribution with respect to the total weight of the first and second red phosphors is adjusted so that the average color rendering index Ra is 80 ≦ Ra ≦ 97. . In particular, the weight ratio of the second red phosphor to the total weight of the first and second red phosphors is adjusted to 25% or less so that the average color rendering index Ra is 80 ≦ Ra ≦ 85. Alternatively, the weight ratio of the second red phosphor to the total weight of the first and second red phosphors is adjusted to 25% to 75% so that the average color rendering index Ra is 85 ≦ Ra ≦ 90. Or the weight ratio of the second red phosphor to the total weight of the first and second red phosphors is adjusted to 75% or more so that the average color rendering index Ra is 90 ≦ Ra ≦ 97. Preferably it is.

  In the light emitting device having the above characteristics, when two types of red phosphors are used, the average color rendering index Ra that can be used as high color rendering illumination when used as a light source for illumination is desired in an area of 80 or more. It is possible to select the average color rendering index Ra. In the CIE, the average color rendering index Ra is defined as being usable at homes, hotels, stores, schools, etc. when 80 ≦ Ra <90, and usable at art museums, etc. when Ra ≧ 90. By adjusting the mixing ratio of the red phosphor, it is possible to adjust the color rendering properties and the light emission efficiency according to the use environment. In addition, by increasing the blending ratio of the second red phosphor, the average color rendering index Ra is improved, but the light emission efficiency is relatively lowered. However, in the light emitting device having the above characteristics, since the blending ratio of the first and second red phosphors can be adjusted within the range of 80 ≦ Ra ≦ 97, the blending of the second red phosphor is prioritized when color rendering is prioritized. When the ratio is large and, conversely, when the luminous efficiency is prioritized, it can be applied to various applications by decreasing the ratio.

  Furthermore, by using two types of red phosphors, it is possible to achieve a high color rendering property while maintaining luminous efficiency as compared with the case of using only one type of red phosphor for the special color rendering index R9. Furthermore, when priority is given to color rendering, the blending ratio of the second red phosphor is increased, and conversely, when priority is given to light emission efficiency, it can be applied to various applications by decreasing it.

  Furthermore, in the light emitting device having the above characteristics, is the phosphor layer formed by mixing the granular green phosphor, the granular first red phosphor and the granular second red phosphor in a transparent resin? Alternatively, a green phosphor layer in which the granular green phosphor is mixed in a transparent resin, a first red phosphor layer in which the granular first red phosphor is mixed in a transparent resin, and the granular first in a transparent resin. Formed as a laminated structure in which a second red phosphor layer in which two red phosphors are mixed is laminated, or the phosphor layer is a green phosphor layer in which a granular green phosphor is mixed in a transparent resin; It is preferable to form a laminated structure in which a red phosphor layer obtained by mixing the granular first red phosphor and the granular second first red phosphor red phosphor on a transparent resin is laminated.

  Further, the light emitting element is sealed with the phosphor layer, the lowermost layer of the phosphor layer, or a transparent resin layer not including a phosphor provided on the light emitting element side from the phosphor layer. Is preferred. Moreover, it is preferable that the said green fluorescent substance layer is located in the upper layer from the layer in which the said 1st red fluorescent substance and the said 2nd red fluorescent substance exist.

  Thereby, various structures according to the mounting form are possible as the structure of the phosphor layer and the sealing structure of the light emitting element. In particular, by providing the green phosphor layer on the upper part of the phosphor layer, it is possible to suppress the green light emitted from the green phosphor from being absorbed by the first or second red phosphor, High luminous efficiency can be realized.

  Furthermore, the median value of the particle size of the green phosphor is 8 μm or more and 20 μm or less, and the median value of the particle size of the first red phosphor and the second red phosphor is 5 μm or more and 15 μm or less. Each is preferable. As a result, each phosphor can be used in a region where the luminous efficiency is high, and as a result, high luminous efficiency can be realized. Furthermore, it is preferable that the transparent resin of each layer of the phosphor layer is a silicone resin having a viscosity before curing of 3 Pa · s to 20 Pa · s. Thereby, the process which disperse | distributes and uniformly each granular fluorescent substance in transparent resin is realizable with mass-productivity.

  As described above, the light emitting device having the above characteristics can improve the average color rendering index Ra and the special color rendering index R9, and suppress the decrease in the light emission efficiency as much as possible. Provision is possible.

Schematic sectional view schematically showing a schematic structure of an embodiment of a light emitting device according to the present invention The figure which displays as a list the peak emission wavelength of each fluorescent substance of Examples 1-7 of the light-emitting device which concerns on this invention, a compounding ratio, and an optical characteristic. The figure which displays as a list the peak light emission wavelength of each phosphor of Comparative Examples 1 and 2, the compounding ratio, and the optical characteristics The figure which shows the emission spectrum of Examples 1-7 and Comparative Examples 1 and 2. The figure which shows the relationship between the emitted light intensity (relative value) in Examples 1-7, and the compounding ratio of a 2nd red fluorescent substance. The figure which shows the relationship between the average color-rendering evaluation number Ra in Examples 1-7, and the compounding ratio of 2nd red fluorescent substance. FIG. 2 is a schematic cross-sectional view of a main part schematically showing a schematic structure of another embodiment in which the phosphor layer of the light emitting device according to the present invention has a multilayer structure. FIG. 2 is a schematic cross-sectional view of a main part schematically showing a schematic structure of another embodiment in which the phosphor layer of the light emitting device according to the present invention has a multilayer structure. The schematic sectional drawing which shows typically the schematic structure of another embodiment mounted in the lead frame package of the light-emitting device which concerns on this invention. The schematic perspective view which shows typically the schematic structure of another embodiment which made the fluorescent substance layer of the light-emitting device concerning this invention the dome shape

  An embodiment of a light-emitting device according to the present invention (hereinafter referred to as “the present light-emitting device” as appropriate) will be described based on the drawings on the assumption that it is used as a white light source for illumination. Note that in the drawings showing the structure of the light emitting device, there are places where important parts are emphasized or schematically illustrated, and therefore the dimensional ratio of each part does not necessarily match the actual structure. .

  FIG. 1 is a schematic cross-sectional view schematically showing an example of the light emitting device. As shown in FIG. 1, the light emitting device 1 includes a ceramic substrate 2, a wiring pattern 3 (3a, 3k), an electrode land 4 (4a, 4k), a phosphor layer 5, an LED chip 6, a wire 7, and a printing resistance element. 8. A resin dam 9 is provided. 1A is a top view, and FIG. 1B is a cross-sectional view of the main part in the XZ cross section for cutting the LED chip 6 and the wire 7. In FIG. 1A, in order to clarify the connection relationship, the inside is shown transparent.

  The ceramic substrate 2 has a rectangular shape in a top view. As an example, the outer shape is 24 mm × 20 mm and the thickness is 1 mm. The wiring patterns 3a and 3k are formed on the ceramic substrate 2 by a screen printing method or the like so as to face each other. Each of the light emitting devices 1 has an arc shape that is partly cut out from the ring as viewed from the upper surface of the light emitting device 1. The electrode lands 4a and 4k are formed of a material such as Ag-Pt by a screen printing method or the like as an electrode for external connection (for example, for power supply). An example of the thickness is 20 μm. The electrode land 4a is connected to one end of the wiring pattern 3a via a lead wire, and the electrode land 5k is connected to one end of the wiring pattern 3k via a lead wire.

  The phosphor layer 5 converts part of the light (for example, blue light) emitted from the LED chip 6 into green light and two types of red light, and mixes the light of the four colors to emit as white light. To do. The phosphor layer 5 is made of an annular, phosphor-mixed resin in which a granular green phosphor, a granular first red phosphor and a granular second red phosphor are uniformly dispersed and mixed in a transparent resin. For example, the resin dam 9 is formed by being injected into the inside of the resin dam 9 and thermally cured at 100 ° C. for 1 hour and then at 150 ° C. for 3 to 5 hours. The phosphor layer 5 functions as a sealing resin for sealing the LED chip 6. The thickness of the phosphor layer 5 is substantially the same as the height of the resin dam 9, and is larger than the thickness of the LED chip 6, for example, about 0.6 to 1.0 mm.

  As a preferred embodiment of the transparent resin, a silicone resin having a viscosity before curing of 3 Pa · s to 20 Pa · s is used. In addition, fine silica particles are mixed in the silicone resin as an example in order to suppress sedimentation of each phosphor and to further diffuse light emitted from the LED chip 6 and each phosphor efficiently. In addition, it is not always necessary to mix a sedimentation inhibitor such as silica particles or a diffusing agent.

As a green phosphor, the peak emission wavelength is in the wavelength range of 510 nm or more and 550 nm or less, and Al ₅ Lu _x O _y : Ce-based phosphor, Ca ₃ (Sc _1-x , Mg _x ) ₂ Si ₃ O ₁₂ : Ce A phosphor based on a phosphor (preferably 0.01 ≦ x ≦ 0.4) or an Al ₅ O ₁₂ Y ₃ : Ce phosphor is used. Furthermore, as the green phosphor, a trivalent cerium-activated silicate phosphor represented by the following general formula can be used.
General formula: MI ₃ (MII _1-x , Ce _x ) ₂ (SiO ₄ ) ₃
However, MI is at least one element selected from Mg, Ca, Sr, and Ba, and MII is at least one selected from Al, Ga, In, Sc, Y, La, Gd, and Lu. It is a seed element, and 0.01 ≦ x ≦ 0.4.

The half width of the emission spectrum of the green phosphor is preferably wider because there is only one kind of green phosphor. For example, a phosphor of 95 nm or more is used. The LuAG phosphor, the CSMS phosphor, and the YAG phosphor are all phosphors having a garnet crystal structure using Ce as an activator, and Ce is used as an activator. It is a green phosphor suitable for obtaining a wide (95 nm or more) fluorescence spectrum and obtaining high color rendering properties. For example, 102 nm is obtained for the full width at half maximum for Al ₅ Lu _x O _y : Ce phosphor, and 103 nm is obtained for Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce phosphor.

As a first red phosphor, the peak emission wavelength is within the wavelength range to less than _{610nm 625nm, (Sr 1-y} , Ca y) 1-x AlSiN 3: Eu x phosphor (where, 0.001 ≦ x ≦ 0.05 and 0 ≦ y <0.2 are preferred.).

As a second red phosphor, the peak emission wavelength is within 670nm or less in the wavelength range of _{625nm, (Sr 1-y,} Ca y) 1-x AlSiN 3: Eu x phosphor (where, 0.001 ≦ . x ≦ 0.05,0.2 ≦ y <1 is preferable), _{or, Ca 1-x AlSiN 3:} Eu x phosphor (where, using the preferred) is 0.001 ≦ x ≦ 0.05. To do.

_{(Sr 1-y, Ca y} ) 1-x AlSiN 3: Eu x phosphor _is, Ca 1-x AlSiN _3: In Eu _x phosphor, which part or all of Ca was substituted for Sr Both of them are phosphors with little variation in fluorescence characteristics with respect to temperature changes. Therefore, when these are used as the first and second red phosphors, the temperature dependence of the light emission in the red region can be reduced as the light emitting device, and further, the Ca _{3 having a} fluorescence characteristic of less temperature dependence as the green phosphor. By using (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce phosphor and Al ₅ Lu _x O _y : Ce phosphor in the same manner, a light emitting device with low temperature dependence of the entire light emission characteristics can be realized. . That is, a light-emitting device having high color rendering properties with low temperature dependence can be realized.

_{Further, (Sr 1-y, Ca} y) 1-x AlSiN 3: Eu x phosphor and _Ca 1-x AlSiN _3: Since Eu _x phosphor has a specific gravity difference is small, as described later, the light emitting element When added to the transparent resin for sealing, the variation in sedimentation due to the difference in specific gravity is small, and the variation in the light emission characteristics of the light emitting device including the color rendering can be reduced. It is to be noted that, in the following _{text, (Sr 1-y, Ca} y) 1-x AlSiN 3: Eu x _phosphor, Ca 1-x AlSiN _3: the Eu _x phosphor, and appropriately simplified, (Sr , Ca) AlSiN ₃ : Eu phosphor and CaAlSiN ₃ : Eu phosphor.

Furthermore, nitride phosphors represented by the following general formula can be used as the first and second red phosphors.
General formula: (MI _1-x , Eu _x ) MIISiN ₃
However, MI is at least one element selected from Mg, Ca, Sr, and Ba, and MII is at least one selected from Al, Ga, In, Sc, Y, La, Gd, and Lu. It is a seed element, and 0.001 ≦ x ≦ 0.05.

The half width of the emission spectrum of the first and second red phosphors is preferably wider as in the case of the green phosphor. However, since two types are used, the emission spectrum as a whole red has no peak at a specific wavelength. For example, a phosphor having a half width of about 85 to 110 nm is used. For example, 88 nm is used for the (Sr, Ca) AlSiN ₃ : Eu phosphor, and 90 nm is used for the CaAlSiN ₃ : Eu phosphor.

  The particle diameter of each phosphor is preferably such that the median value (D50) is 8 μm to 20 μm for the green phosphor and 5 μm to 15 μm for the first and second red phosphors.

  The phosphor layer 5 is an important component in the light emitting device 1, and the peak emission wavelength of the emission spectrum of each phosphor and the blending ratio of each phosphor affect the luminous efficiency and color rendering, and will be described later. Seven embodiments will be described in detail.

  The LED chip 6 is a bare chip of a semiconductor light emitting element that emits light including a blue component having a peak emission wavelength in a blue region (wavelength: 430 nm or more and 490 nm or less), and is configured by an InGaN-based LED. When the peak emission wavelength is less than 430, the color rendering property is lowered, and when it exceeds 490 nm, the brightness in white is lowered. Therefore, the above wavelength range is preferable from the viewpoint of practicality. In the present embodiment, as an example, a peak emission wavelength near 450 nm is used. In the present embodiment, the LED chips 6 are die-bonded on the substrate 2, and a plurality of LED chips 6 are linearly arranged so as to be substantially parallel to one side (X direction) of the substrate 2. The number of chips in the column is maximized in the vicinity of the center of the annular shape formed by the wiring pattern 3 and the printed resistance element 8 so that the wiring pattern 3 and the printed resistance element 8 can be arranged at high density in the area surrounded by the wiring pattern 3. The number of chips in the row decreases as the distance from the substrate to the periphery of the substrate increases. In the example shown in FIG. 1, 12 LED chips 6 connected in series are connected in 12 rows in parallel. The LED chip 6 has a structure in which light emission is emitted from the upper surface of the chip, and an electrode pad (not shown) for anode or cathode for connecting the LED chip 6 or the wiring pattern 3 adjacent to the chip surface and the wire 7 with each other. ) Is formed. When the LED chip 6 is a back emission type, wirings and lands corresponding to the wires 7 are formed on the substrate 2 in advance, and the LED chip 6 is placed on the surface of the substrate 2 with the electrode pads facing the surface of the substrate 2 via bumps. It may be mounted by flip chip connection.

The printed resistance element 8 is provided for the purpose of increasing the electrostatic withstand voltage, and is formed of RhO ₂ having a width of 200 μm, a width of 6 μm, and a resistance value of 50 MΩ as an example. As shown in FIG. 1, the printed resistance element 8 is disposed so as to be connected to one end of the wiring pattern 3 a and one end of the wiring pattern 3 k, and forms an arc shape partly cut out from the circular ring. In the present embodiment, each of the wiring pattern 3a, the printed resistance element 8, and the wiring pattern 3k is arranged so as to constitute a part of the same ring.

The resin dam 9 is a resin for blocking the phosphor layer 5 that is a sealing resin, and is made of a colored material (white or milky white is preferable). In this embodiment, the resin dam 9 is made of a white silicone resin (containing filler TiO ₂ ) and formed in an annular shape having a width of 1 mm and a diameter of 9 mm. The resin dam 9 was formed by pouring the silicone resin into an annular shape, followed by thermosetting at 150 ° C. for 1 hour. As shown in FIG. 1A, the resin dam 9 is preferably formed so as to cover an arc-shaped portion formed by the wiring pattern 3 and the printed resistance element 8.

  Next, regarding the relationship between the configuration of the phosphor layer 5 which is an important component in the light emitting device 1 and the optical characteristics (emission intensity, average color rendering index Ra, special color rendering index R9, color temperature), the following 7 This will be described based on the first to seventh embodiments. In each embodiment, at least one of the peak emission wavelength of the emission spectrum of each phosphor and the blending ratio of each phosphor is different from each other. The blending ratio is defined by the weight ratio of each phosphor. In each example, the mixing ratio of the green phosphor and the sum of the first and second red phosphors is 5: 1.

  Further, the optical characteristics were measured for two comparative examples 1 and 2 to be described later for comparison with each example. In each of the examples and comparative examples, an InGaN-based LED having a peak emission wavelength near 450 nm was used as the LED chip 6, and both were assumed to be used as a white light source near a color temperature of 3000 to 3300K. Moreover, in each Example and Comparative Example, since structures other than the phosphor layer 5 are the same as the above-described structures, a duplicate description is omitted.

<Example 1>
In Example 1, an Al ₅ Lu _x O _y : Ce phosphor having a peak emission wavelength in the vicinity of 535 nm is used as the green phosphor, and a peak emission wavelength is in the vicinity of 620 nm as the first red phosphor (Sr, Ca ) AlSiN ₃ : Eu phosphor was used as the second red phosphor, and CaAlSiN ₃ : Eu phosphor having a peak emission wavelength in the vicinity of 650 nm was used. Further, the blending ratio of the green phosphor, the first red phosphor, and the second red phosphor was set to 5: 0.98: 0.02. The relative value of the emission intensity (based on the lowest emission intensity in Examples 1 to 7) is 118.6%, the average color rendering index Ra is 81.65, the special color rendering index R9 is 9.31, and the color The temperature became 3263K.

<Example 2>
In Example 2, as a green phosphor, a Ca ₃ (Sc, Mg) ₂ Si ₃ O ₁₂ : Ce-based phosphor having a peak emission wavelength near 520 nm is used as a first red phosphor, and a peak emission wavelength is around 620 nm. the a (Sr, Ca) AlSiN _3: Eu-based phosphors, as the second red phosphor, CaAlSiN ₃ has a peak emission wavelength in the vicinity of 650 nm: using Eu phosphor. Further, the blending ratio of the green phosphor, the first red phosphor, and the second red phosphor was set to 5: 0.98: 0.02. The difference from Example 1 is the peak emission wavelength of the green phosphor and the phosphor material.

  The relative value of the emission intensity was 109.3%, the average color rendering index Ra was 83.57, the special color rendering index R9 was 12.16, and the color temperature was 3004K. Compared with Example 1, since the peak emission wavelength of the green phosphor was shortened, the emission intensity was slightly reduced, but the color rendering was increased.

<Example 3>
In Example 3, an Al ₅ Lu _x O _y : Ce phosphor having a peak emission wavelength in the vicinity of 535 nm is used as the green phosphor, and a peak emission wavelength in the vicinity of 620 nm is used as the first red phosphor (Sr, Ca ) AlSiN ₃ : Eu-based phosphor was used as the second red phosphor, and (Sr, Ca) AlSiN ₃ : Eu-based phosphor having a peak emission wavelength in the vicinity of 630 nm was used. The blending ratio of the green phosphor, the first red phosphor, and the second red phosphor was set to 5: 0.83: 0.17. The difference from Example 1 is the peak emission wavelength of the second red phosphor, the phosphor material, and the mixing ratio of the first and second red phosphors.

  The relative value of the emission intensity was 115.9%, the average color rendering index Ra was 82.26, the special color rendering index R9 was 9.44, and the color temperature was 3041K. Compared with Example 1, the peak emission wavelength of the second red phosphor was shortened, but since the compounding ratio was increased, the emission intensity was slightly reduced but the high level was maintained and the color rendering was also improved. .

<Example 4>
In Example 4, an Al ₅ Lu _x O _y : Ce phosphor having a peak emission wavelength in the vicinity of 535 nm is used as the green phosphor, and a peak emission wavelength in the vicinity of 620 nm is used as the first red phosphor (Sr, Ca ) AlSiN ₃ : Eu phosphor was used as the second red phosphor, and CaAlSiN ₃ : Eu phosphor having a peak emission wavelength in the vicinity of 650 nm was used. The blending ratio of the green phosphor, the first red phosphor, and the second red phosphor was set to 5: 0.78: 0.22. The difference from Example 1 is the blending ratio of the first and second red phosphors.

  The relative value of the emission intensity was 115.0%, the average color rendering index Ra was 83.58, the special color rendering index R9 was 20.24, and the color temperature was 2987K. Compared with Example 1, since the blending ratio of the second red phosphor was increased, the emission intensity was slightly reduced but maintained at a high level, and higher color rendering was obtained. Ra (standard value) = 85 Alternatively, it can be used for lighting fixtures targeting Ra (minimum value) = 80.

<Example 5>
In Example 5, an Al ₅ Lu _x O _y : Ce phosphor having a peak emission wavelength around 535 nm is used as a green phosphor, and a peak emission wavelength is around 620 nm as a first red phosphor (Sr, Ca ) AlSiN ₃ : Eu phosphor was used as the second red phosphor, and CaAlSiN ₃ : Eu phosphor having a peak emission wavelength in the vicinity of 650 nm was used. The blending ratio of the green phosphor, the first red phosphor, and the second red phosphor was set to 5: 0.5: 0.5. The difference from Example 1 is the blending ratio of the first and second red phosphors.

  The relative value of the emission intensity was 110.0%, the average color rendering index Ra was 86.41, the special color rendering index R9 was 36.02, and the color temperature was 3323K. Compared with Example 1 and Example 4, since the compounding ratio of the second red phosphor was increased, the emission intensity was reduced to 110%, but higher color rendering was obtained, and Ra (minimum value) = 85. It can be used for lighting fixtures targeting

<Example 6>
In Example 6, an Al ₅ Lu _x O _y : Ce phosphor having a peak emission wavelength in the vicinity of 535 nm is used as the green phosphor, and a peak emission wavelength in the vicinity of 620 nm is used as the first red phosphor (Sr, Ca ) AlSiN ₃ : Eu phosphor was used as the second red phosphor, and CaAlSiN ₃ : Eu phosphor having a peak emission wavelength in the vicinity of 650 nm was used. Moreover, the blending ratio of the green phosphor, the first red phosphor, and the second red phosphor was set to 5: 0.25: 0.75. The difference from Example 1 is the blending ratio of the first and second red phosphors.

  The relative value of the emission intensity was 105.0%, the average color rendering index Ra was 91.1, the special color rendering index R9 was 55.9, and the color temperature was 3268K. Compared with Example 1, Example 4, and Example 5, the compounding ratio of the second red phosphor was increased, so although the emission intensity was reduced to 105%, higher color rendering properties were obtained, and Ra (standard Value) = 90 can be used for lighting fixture applications.

<Example 7>
In Example 7, an Al ₅ Lu _x O _y : Ce phosphor having a peak emission wavelength in the vicinity of 535 nm is used as the green phosphor, and a peak emission wavelength is in the vicinity of 620 nm as the first red phosphor (Sr, Ca ) AlSiN ₃ : Eu phosphor was used as the second red phosphor, and CaAlSiN ₃ : Eu phosphor having a peak emission wavelength in the vicinity of 650 nm was used. The blending ratio of the green phosphor, the first red phosphor, and the second red phosphor was set to 5: 0.02: 0.98. The difference from Example 1 is the blending ratio of the first and second red phosphors.

  The relative value of the emission intensity was 100.0%, the average color rendering index Ra was 93.7, the special color rendering index R9 was 82.75, and the color temperature was 3316K. Compared with Example 1 and Examples 4-6, since the compounding ratio of the second red phosphor was further increased, the emission intensity was reduced to 100%, but higher color rendering properties were obtained, and Ra (minimum value). ) = 90 can be used for lighting fixtures.

  Next, Comparative Example 1 and Comparative Example 2 will be described. Each comparative example is a combination of a blue LED, a yellow phosphor and a red phosphor disclosed in Patent Document 1, and one type of yellow phosphor and one red phosphor are used.

<Comparative example 1>
In Comparative Example 1, the yellow phosphor has a peak emission wavelength near 630 nm as a (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce phosphor having a peak emission wavelength near 560 nm and a red phosphor. The (Sr, Ca) AlSiN ₃ : Eu-based phosphor having the same was used. The blending ratio of yellow phosphor and red phosphor was 3.3: 1. The relative value of the emission intensity was 124.0%, the average color rendering index Ra was 73.0, the special color rendering index R9 was -5.0, and the color temperature was 2950K.

<Comparative example 2>
In Comparative Example 2, the yellow phosphor has a peak emission wavelength near 650 nm as a (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce phosphor having a peak emission wavelength near 560 nm and a red phosphor. CaAlSiN ₃ : Eu-based phosphor having Further, the blending ratio of the yellow phosphor and the red phosphor was set to 3.9: 1. The relative value of the emission intensity was 114.0%, the average color rendering index Ra was 77.0, the special color rendering index R9 was 20.0, and the color temperature was 3000K.

  Next, the measurement results of the optical characteristics of Examples 1 to 7 and Comparative Examples 1 and 2 are comparatively examined with reference to the following FIGS. FIG. 2 is a table listing the peak emission wavelengths and blending ratios and optical characteristics of the phosphors of Examples 1 to 7, and FIG. 3 shows the peak emission wavelengths and blends of the phosphors of Comparative Examples 1 and 2. It is a figure which displays a list of ratios and optical characteristics. FIG. 4 shows an emission spectrum of each example and each comparative example. FIG. 5 shows the relationship between the emission intensity (relative value) and the blending ratio of the second red phosphor in each example. FIG. 6 shows the relationship between the average color rendering index Ra and the blend ratio of the second red phosphor in each example. 5 and 6, the measured values of Examples 1 and 4 to 7 are indicated by diamonds (♦), the measured values of Example 2 are indicated by triangles (▲), and the measured values of Example 3 are indicated by circles (●). The measured values of Comparative Examples 1 and 2 are indicated by broken lines as reference values.

  First, Comparative Examples 1 and 2 both have an average color rendering index Ra of less than 80, and have not reached an area usable as a white light source for high color rendering illumination, but Examples 1 to 7 are all average color rendering. The evaluation number Ra exceeds 80, and has reached an area usable as a white light source for high color rendering illumination. Further, even when Examples 3 and 4 and Comparative Example 2 having comparable light emission intensities are compared, it can be seen that Examples 3 and 4 have higher color rendering properties.

  Next, as shown in FIGS. 5 and 6, when the blending ratio of the second red phosphor increases (conversely, when the blending ratio of the first red phosphor decreases), the emission intensity decreases, and conversely, the average color rendering evaluation It can be seen that the number Ra increases. That is, by adjusting the blending ratio of the first and second red phosphors, it is possible to obtain a desired average color rendering index Ra and emission intensity in an area where the average color rendering index Ra is 80 or more. For example, when the color rendering property of 80 ≦ Ra ≦ 85 is targeted, the blending ratio of the second red phosphor is adjusted to 25% or less, and when the color rendering property of 85 ≦ Ra ≦ 90 is targeted, the second When the blending ratio of the red phosphor is adjusted to 25% or more and 75% or less and the color rendering property of 90 ≦ Ra ≦ 97 is targeted, the blending ratio of the second red phosphor may be adjusted to 75% or more.

  When Example 1 and Example 2 with the same compounding ratio of the second red phosphor are compared, Example 1 has higher emission intensity but lower color rendering. On the other hand, when Example 2 and Example 5 having substantially the same emission intensity are compared, Example 5 has higher color rendering. That is, it can be seen that the color rendering can be improved while maintaining the emission intensity by adjusting the peak emission wavelength of the green phosphor and the mixing ratio of the first and second red phosphors.

  The emission intensity of Examples 1 and 3 to 5 is equal to the emission intensity of Comparative Example 1, but is larger than that of Comparative Example 2. However, as described above, the color rendering is improved as compared with Comparative Examples 1 and 2. Since Examples 2, 6, and 7 place importance on improving color rendering properties than Examples 1 and 3 to 5 as described above, the emission intensity is lower than that of Comparative Example 1. However, the light emission intensity of Comparative Example 2 is at the same level. Note that the light emission intensity at the same level means a light emission intensity within a range of ± 15% from the standard light emission intensity.

  From FIG. 5 and FIG. 6, on the lines connecting the measured values of Examples 1 and 4 to 7 that differ only in the blending ratio of the first and second red phosphors, examples in which the peak emission wavelength of the second red phosphor differs. It can be seen that the measured values of 3 almost overlap. In Examples 1 and 4 to 7, the peak emission wavelengths of the first and second red phosphors are 620 nm and 650 nm, and the difference is 30 nm. In Example 3, the first and second red phosphors have different wavelengths. Each peak emission wavelength is 620 nm and 630 nm, and the difference is 10 nm. Thus, even if the difference between the peak emission wavelengths of the first and second red phosphors is 10 nm, the mixing ratio of the first and second red phosphors can be adjusted, or the peak emission wavelength of the green phosphor It can be seen that the emission intensity and the color rendering can be controlled by adjusting the mixing ratio of the first and second red phosphors. Further, the peak emission wavelengths of the first and second red phosphors are shorter than the intermediate value with the peak emission wavelength of the first red phosphor being shorter than the intermediate value between 620 nm and 630 nm (for example, 625 nm). It can be seen that the peak emission wavelength of the red phosphor may be set longer than the intermediate value. Referring to the red spectral luminance emissivity (0.4 to 0.8) of test color number 9, the peak emission wavelength of the first red phosphor is approximately in the range of 610 to 625 nm, and the peak of the second red phosphor. It is considered preferable that the emission wavelength is set in a range of approximately 625 nm or more and 670 nm or less because the effect of improving the special color rendering index R9 is increased.

  As described above, according to the present light emitting device 1, since 144 LED chips 6 are arranged in a circular region, a 30 W class semiconductor light emitting device can be realized, and a 100 W incandescent lamp and halogen lamp are also particularly suitable for general lighting applications. , HID lamps and the like can be substituted and applied to a wide range of applications. In addition, since the resin dam 9 has an annular shape, the optical design (lens and reflector design) required for use in lighting applications is relatively easy. Furthermore, since the arrangement of the LED chips 6 is substantially circular and uniformly dispersed, variations in the color rendering properties, chromaticity, color temperature, etc. of the light emitted from the light emitting device 1 can be suppressed. In addition, if a transparent resin in which phosphors having different peak emission wavelengths and blending ratios are mixed is prepared in advance, the transparent resin is added to the intermediate product of the light emitting device 1 formed up to the resin dam 9 in the resin dam 9. The light-emitting device 1 having various optical characteristics can be obtained by simply injecting it into the substrate and thermally curing it.

<Another embodiment>
Hereinafter, another embodiment of the above embodiment will be described.

<1> In the above embodiment, the phosphor layer 5 is a mixture of the green phosphor, the first red phosphor, and the second red phosphor (one-layer structure). It may be configured to be separated into layers or three layers.

  For example, as schematically shown in FIG. 7, the phosphor layer 5 includes a first red phosphor layer 5a in which a granular first red phosphor is mixed with a transparent resin, and a second red phosphor that is granular in the transparent resin. The second red phosphor layer 5b mixed with the green phosphor layer 5c obtained by mixing the transparent green resin with the granular green phosphor may be laminated in order from the LED chip 6 side. In this case, what is necessary is just to determine the compounding ratio of each fluorescent substance in each whole fluorescent substance layer 5a-5c similarly to the case where the fluorescent substance layer 5 is comprised by 1 layer.

  Here, as shown in FIG. 7A, it is preferable to form the three phosphor layers 5 on the upper layer in which the LED chip 6 is sealed with the transparent resin layer 10 not containing the phosphor. In this case, the thickness of the transparent resin layer 10 is preferably equal to or greater than the thickness of the LED chip 6 (about 80 to 200 μm). Moreover, as shown in FIG.7 (b), without providing the transparent resin layer 10, in the upper layer which sealed the LED chip 6 with the 1st red fluorescent substance layer 5a, the remaining 2nd 2nd red fluorescent substance layers 5b. And the green phosphor layer 5c may be laminated. The order of the first red phosphor layer 5a and the second red phosphor layer 5b may be interchanged.

  Further, as schematically shown in FIG. 8, the phosphor layer 5 includes a red phosphor layer 5 d obtained by mixing a granular first red phosphor and a second red phosphor in a transparent resin, and a granular green in the transparent resin. The green phosphor layer 5c mixed with the phosphor may be laminated in order from the LED chip 6 side. In this case, the blending ratio of the respective phosphors in the entire phosphor layers 5c and 5d may be determined in the same manner as in the case where the phosphor layer 5 is composed of one layer.

  Here, as shown in FIG. 8A, the two phosphor layers 5 are preferably formed on the upper layer in which the LED chip 6 is sealed with the transparent resin layer 10 not containing the phosphor. Further, as shown in FIG. 8B, the green phosphor layer 5c may be laminated on the upper layer in which the LED chip 6 is sealed with the red phosphor layer 5d without providing the transparent resin layer 10.

The (Sr, Ca) AlSiN ₃ : Eu-based phosphor and CaAlSiN ₃ : Eu-based phosphor used in the first and second red phosphors exemplified in the above embodiment have a wide absorption band and have a green component light. 7 or 8, in the configuration shown in FIG. 7 or FIG. 8, by providing the green phosphor layer 5c on the uppermost layer of the phosphor layer 5, the green component light emitted from the green phosphor is first or second. Absorption by the red phosphor can be suppressed, and as a result, a decrease in luminous efficiency can be suppressed.

  Further, when the phosphor layer 5 has a multi-layer structure, each layer may be injected and thermally cured one by one, or may be formed in order, or only a part or all of the layers are first injected with a resin. Alternatively, it may be formed by thermosetting at once. In other words, the boundaries between the layers do not necessarily have to be clearly separated. Furthermore, you may mix the structure shown in FIG. 7 or FIG. For example, the first red phosphor layer 5a, the second red phosphor layer 5b, and one or a plurality of the red phosphor layers 5d having different blending ratios may be appropriately combined to finally need the first red phosphor. And the second red phosphor may be obtained. Accordingly, the number of phosphor layers 5 is not limited to 1 to 4.

<2> In the above embodiment, the LED chip 6 is an InGaN-based LED of a semiconductor light emitting device that emits light containing a blue component having a peak emission wavelength (emission peak) in the blue region (wavelength: 430 nm or more and 490 nm or less). Although the case where it comprises is demonstrated, this invention is applicable also when the peak light emission wavelength of light emission from LED chip 6 exists in a purple region (wavelength: 350 nm or more and less than 430 nm) from a near ultraviolet region. The LED chip 6 is preferably composed of an InGaN-based LED, as in the above embodiment. However, when the emission spectrum of the LED chip 6 is shifted to the short wavelength side, the blue component light emitted from the LED chip 6 is insufficient or lacking. In addition to the body, the first red phosphor, and the second red phosphor, blue component light (for example, having a peak emission wavelength in the range of 430 nm to 490 nm) is excited by near ultraviolet light or violet light. It is preferable to add a blue phosphor. As the blue phosphor, for example, a divalent europium activated halophosphate phosphor represented by the following three general formulas, a divalent europium activated aluminate phosphor, a divalent europium and manganese co-activated An aluminate phosphor or the like can be used.
General formula: (M1, Eu) ₁₀ (PO ₄ ) ₆ · Cl ₂
General formula: a (M2, Eu) O.bAl ₂ O ₃
General _{formula: a (M2, Eu c,} Mn d) O · bAl 2 O 3
However, M1 is at least one element selected from Mg, Ca, Sr and Ba, and M2 is at least one element selected from Mg, Ca, Sr, Ba and Zn, a, b, c and d are numbers satisfying a> 0, b> 0, 0.1 ≦ a / b ≦ 1.0, and 0.001 ≦ d / c ≦ 0.

  Even when the blue phosphor is used, since the emission of blue light is merely a change from the LED chip 6 to the blue phosphor, two types of red phosphors, the first red phosphor and the second red phosphor, are used. It is obvious that the effect of the present invention by using can be obtained in the same manner as in the above embodiment. Further, the phosphor layer 5 including the blue phosphor may have a multilayer structure as shown in the above-described another embodiment <1>. In this case, the blue phosphor layer is preferably provided in an upper layer, that is, the uppermost layer, than the layer including the green phosphor, the first red phosphor, and the second red phosphor.

  <3> In the above embodiment, as illustrated in FIG. 1, the mounting form in which a plurality of LED chips 6 are mounted on the ceramic substrate 2 is illustrated, but the shape, material, and size of the ceramic substrate 2, the LED chip 6 The number and the shape of the mounting area, the shape and thickness of the phosphor layer 5, the material and the number of layers of the transparent resin are not limited to the above embodiment. Moreover, it replaces with the resin dam 9, and the resin-made flame | frame which has a recessed part as shown in FIG. 1 of patent document 1 is formed on the ceramic substrate 2, LED chip 6 is mounted in the said recessed part, and each phosphor is included. A transparent resin may be injected into the recess to seal the LED chip 6.

  <4> Further, the LED chip 6 may be mounted on a package using a lead frame instead of being mounted on the ceramic substrate 2. 9A and 9B schematically show a cross-sectional structure when mounted on a lead frame package. 9A and 9B, each of the mounting examples includes two lead terminals 11 and 12, one of which serves as an anode terminal and the other serves as a cathode terminal, and a recess for housing the LED chip 6 in one of the lead terminals. The LED chip 6 is die-bonded on the concave portion of the one lead terminal, and the green phosphor, the first red phosphor, and the second red phosphor are placed on the LED chip 6 and the lead terminals 11 and 12. The phosphor layer 5 is formed by being filled with the transparent resin to be included. A package body 13 for fixing the lead terminals 11 and 12 made of an opaque resin is formed below the lead terminals 11 and 12 and around the area filled with the transparent resin.

  FIG. 9A shows a mounting example in which two chips are mounted. One electrode pad (not shown) of one LED chip 6 and one lead terminal are connected to each other by a wire 7. The other electrode pad (not shown) and one electrode pad (not shown) of the other LED chip 6 are connected to each other by a wire 7, and the other electrode pad (not shown) of the other LED chip 6 is connected. The other lead terminal is connected to each other by a wire 7 to form a series circuit of two LED chips 6. Further, in the mounting example of FIG. 9A, a Zener diode 14 as a protection element is interposed between the two lead terminals 11 and 12. Further, FIG. 9B shows a mounting example in which one chip is mounted. One electrode pad (not shown) of the LED chip 6 and one lead terminal are connected to each other by a wire 7, and the other of the LED chip 6 is connected. An electrode pad (not shown) and the other lead terminal are connected to each other by a wire 7.

  In the mounting example of FIG. 9A, the number of LED chips 6 mounted may be three or more. Further, in the mounting examples of FIGS. 9A and 9B, the phosphor layer 5 may have a multilayer structure as shown in the above-described another embodiment <1>.

  <5> Furthermore, the LED chip 6 is mounted on the ceramic substrate 2 and the phosphor layer 5 is not formed in a flat plate shape, but a structure having a dome-like phosphor layer 5 as illustrated in FIG. good.

  Specifically, instead of the ceramic substrate 2, a pair of land portions 16 a and 16 b made of metal film pieces are provided on the upper surface of the insulating film 15, and a pair of external connection made of metal film pieces on the lower surface. Terminal portions 17a and 17b are provided, the land portions 16a and 16b are bonded to the upper surface of the insulating film 15 via the adhesive layer 18, and the terminal portions 17a and 17b are bonded to the lower surface of the insulating film 15 via the adhesive layer 19. A film-like substrate adhered to is used. The land portion 16a and the terminal portion 17a are opposed to each other with the insulating film 15 interposed therebetween, and are electrically connected by two through conductors (not shown) penetrating the insulating film 15. Similarly, the land portion 16b and the terminal portion 17b are opposed to each other with the insulating film 15 interposed therebetween, and are electrically connected by two through conductors (not shown) penetrating the insulating film 15. The number of through conductors may be 1 or 3 or more, respectively. The pair of land portions 16a and 16b are electrically insulated and separated by an elongated gap extending between the land portions in the Y direction. Similarly, the pair of terminal portions 17a and 17b is also electrically insulated and separated by an elongated gap extending between the terminal portions in the Y direction. In the present embodiment <5>, a polyimide film having a thickness of 0.05 mm is used as an example of the insulating film 15. An annular liquid-repellent layer 21 having an opening 20 at the center for exposing a circular region including the central portion of the gap is provided on the pair of land portions 16a and 16b and the gap between them. The LED chip 6 is mounted on the pair of land portions 16a and 16b. In the mounting example shown in FIG. 10, the LED chip 6 is a back-emission type flip chip type LED in which a pair of electrode pads (for anode and cathode) (not shown) is formed on the chip surface. The electrode pads are connected to the land portions 16a and 16b through the vias. When the LED chip 6 is a surface emission type, each electrode pad and the land portions 16a and 16b are connected by wires. A transparent resin obtained by mixing the same three types of phosphors as the green phosphor and the first and second red phosphors as in the above-described embodiment is opened by, for example, a squeegee printing method using a mask member that covers the liquid repellent layer 21. By injecting onto the portion 20 and removing the mask member, it is naturally formed into a dome shape by the liquid repellency of the liquid repellent layer 21 and the surface tension of the transparent resin, and the LED chip 6 is sealed by subsequent thermosetting. A dome-shaped phosphor layer 5 that stops is formed.

  By forming a plurality of sets of a pair of land portions 16a and 16b and a pair of terminal portions 17a and 17b on the front and back of the insulating film 15, a large number of the light emitting elements 1 having the structure shown in FIG. By cutting the insulating film 15 around the pair of land portions 16a and 16b according to the required number, an arbitrary number of dome-shaped main light emitting elements can be obtained. Moreover, the LED chip 6 mounted in the opening part 20 may be two or more.

  <6> In the above-described different embodiments <4> and <5>, the modification of the mounting form of the light-emitting device has been described. The mounting form of the light-emitting device 1 is exemplified in the above-described embodiment and the other embodiments. It is not limited to.

  <7> Further, in the above embodiment, the case where the light emitting device is used as a white light source for illumination has been described. However, the light emitting device adopts a mounting form suitable for a backlight of a liquid crystal display device. By doing so, it can be applied to the backlight.

  <8> Further, in Examples 1 to 7 of the above embodiment, the phosphor combination and blending ratio are defined for a white light source in the vicinity of a color temperature of 3000 to 3300 K. For example, the daylight color in the vicinity of a color temperature of 5000 K is used. For a white light source having a higher color temperature such as the above, a combination of phosphors similar to those described above may be used, and the composition ratio of the phosphors may be appropriately changed. For example, the blending ratio of the green phosphor and the total of the first and second red phosphors is 7.7: 1, and the blending ratio of the first red phosphor and the second red phosphor is 0.85: 0. By setting the value to 15, a light emitting device having high color rendering properties and high light emission efficiency can be realized.

1: Light emitting device 2: Ceramic substrate 3, 3a, 3k: Wiring pattern 4, 4a, 4k: Electrode land 5: Phosphor layer 5a: First red phosphor layer 5b: Second red phosphor layer 5c: Green phosphor Layer 5d: Red phosphor layer 6: LED chip 7: Wire 8: Print resistance element 9: Resin dam 10: Transparent resin layer 11, 12: Lead terminal 13: Package body 14: Zener diode 15: Insulating film 16a, 16b: Land 17a, 17b: Terminal 18, 19: Adhesive layer 20: Opening 21: Liquid repellent layer

Claims (5)

A pair of first land portions and second land portions each formed of a metal film piece and electrically insulated and separated on the upper surface of the insulating film;
On the lower surface of the insulating film, a pair of first and second terminal portions for external connection, each of which is made of a metal film piece and is electrically insulated and separated,
A first through conductor that penetrates the insulating film and electrically connects the first land portion to the first terminal portion;
A second penetrating conductor that penetrates the insulating film and electrically connects the second land portion to the second terminal portion;
A liquid repellent layer formed on the upper surface of the insulating film and having an opening exposing at least a part of the first land portion and the second land portion;
A light emitting element that emits light having a peak emission wavelength in the near ultraviolet to blue region, mounted on the first land portion and the second land portion in the opening,
A transparent resin in which three kinds of phosphors of a green phosphor, a first red phosphor, and a second red phosphor having a peak emission wavelength different from that of the first red phosphor are mixed is injected into the opening. And a dome-shaped phosphor layer for sealing the light emitting element. The peak emission wavelength of the first red phosphor is in a wavelength range of 610 nm or more and less than 625 nm,
2. The light emitting device according to claim 1, wherein a peak emission wavelength of the second red phosphor is in a wavelength range of 625 nm or more and 670 nm or less. The first red _{phosphor, (Sr 1-y, Ca} y) 1-x AlSiN 3: In Eu _x phosphor (where, 0.001 ≦ x ≦ 0.05,0 ≦ y <0.2) Yes,
The second red _{phosphor, (Sr 1-y, Ca} y) 1-x AlSiN 3: Eu x phosphor (where, 0.001 ≦ x ≦ 0.05,0.2 ≦ y <1), _{or, Ca 1-x AlSiN 3:} Eu x phosphor (where, 0.001 ≦ x ≦ 0.05) light emitting device according to claim 2, characterized in that a.   The light emission according to any one of claims 1 to 3, wherein a peak emission wavelength of the green phosphor is in a wavelength range of 510 nm or more and 550 nm or less and an emission spectrum half width is 95 nm or more. apparatus. The green _{phosphor, Al 5 Lu x O y:} Ce based phosphor, _{or, Ca 3 (Sc 1-x} , Mg x) 2 Si 3 O 12: Ce phosphor (where, 0.01 ≦ x ≦ 0.4), or Al ₅ O ₁₂ Y ₃ : Ce-based phosphor, or MI ₃ (MII _1-x , Ce _x ) ₂ (SiO ₄ ) ₃ (where MI is Mg, Ca, Sr and Ba) MII is at least one element selected from Al, Ga, In, Sc, Y, La, Gd, and Lu, and 0.01 ≦ x ≦ 0. 4) The light-emitting device according to claim 4.

Images