JP2007266579A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device capable of improving light emission efficiency while maintaining high color rendering properties by suppressing deterioration of the light emission efficiency caused by using a red luminous phosphor. <P>SOLUTION: The light emitting device comprises an LED chip 2 of blue luminous type as a light emitting element. The LED chip 2 is covered with a phosphor-containing resin layer 9 in which two kinds of phosphors, a phosphor (green phosphor) having luminous peaks at wavelengths 490-510 nm and 530-580 nm and a phosphor (red phosphor) having a luminous peak at 610-660 nm, are mixed and dispersed in a transparent resin. Relating to the peak intensity at each wavelength of an emission spectrum of the phosphor, B/A is preferred to be 0.8-1.2 and C/A is preferred to be 0.5-1.2, where A is a peak intensity at wavelength 490-510 nm, B is a peak intensity at wavelength 530-580 nm, and C is a peak intensity at wavelength 610-660 nm. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light emitting device such as a light emitting diode lamp.

  LED lamps using light emitting diodes (LEDs) are rapidly expanding in various fields such as backlights for liquid crystal displays, mobile phones, information terminals, and indoor / outdoor advertisements. In addition, LED lamps have features such as long life and high reliability, and low power consumption, impact resistance, high purity display color, lightness, thinness, and other features. Application of is also being attempted. When such an LED lamp is applied to various uses, it is important to obtain white light emission.

  Typical methods for realizing white light emission with an LED lamp are (1) a method using three LED chips that emit light in blue, green and red colors, and (2) a blue light emitting LED chip and yellow or orange light emission. And (3) a method of combining an ultraviolet light emitting LED chip and a blue, green and red light emitting three-color mixed phosphor. Of these, the method (2) is generally widely used.

  And as a structure of the LED lamp to which the above-mentioned method (2) is applied, a transparent resin mixed with a phosphor is poured into a cup-shaped frame equipped with an LED chip, and this is solidified to contain the phosphor. A structure in which a resin layer is formed is common (see, for example, Patent Document 1).

  In recent years, in such LED lamps, emphasis is placed on the color appearance called color rendering properties. Color rendering is an evaluation of the color appearance of a light source using illumination close to natural light as the reference light, and the color shift when the test color specified in JIS is illuminated with the sample light source and the reference light, respectively. The numerical value of the size is the color rendering index. The value when viewed with reference light is set to 100, and the numerical value decreases as the color shift increases.

  The color rendering index includes an average color rendering index Ra and a special color rendering index Ri. It is expressed as an average value of 1 to 8 color rendering evaluation values. Since these color rendering evaluation numbers are quantified regardless of whether the direction of the color shift from the reference light of the illumination is in a preferable direction, there may be a case where a preferable color appears even if the color rendering evaluation number is low.

  White LEDs, which are currently in the mainstream, are a combination of a blue light emitting LED chip and a yellow or orange light emitting phosphor. This type of LED has insufficient redness, so that color rendering is not sufficient. There wasn't. For this reason, in addition to yellow or orange light emitting phosphors, color rendering properties are improved by blending red light emitting phosphors such as nitrides and sulfides.

  However, the addition of the red phosphor increases the value of the special color rendering index R9, and the average color rendering index Ra increases accordingly. However, since the light source color is reddish, the color appearance is not always preferable. .

In addition, when the red phosphor is nitride-based, it is excited by absorbing not only the blue light emitted from the LED chip at a wavelength of 460 nm but also the light between the green light and the yellow light emitted from the yellow phosphor. Therefore, when a red light emitting phosphor is used, the luminous efficiency of the LED lamp is greatly reduced.
JP 2001-148516 A

  The present invention has been made to solve such a problem, and it is possible to suppress a decrease in luminous efficiency due to the use of a phosphor emitting red light as much as possible, and to improve luminous efficiency while maintaining high color rendering properties. An object of the present invention is to provide a simple light emitting device.

  The light-emitting device according to claim 1 is a light-emitting element that emits blue light; and light that is excited by blue light emitted from the light-emitting element and has peaks at wavelengths of 490 to 510 nm, 530 to 580 nm, and 610 to 660 nm, respectively. And a phosphor layer containing a phosphor emitting light.

  The light emitting device according to claim 2 is the light emitting device according to claim 1, wherein the emission intensity of the emission peak at a wavelength of 490 to 510 nm in the emission spectrum of the phosphor is A, and the emission intensity of the emission peak at a wavelength of 530 to 580 nm is B. When the emission intensity of the emission peak at a wavelength of 610 to 660 nm is C, the ratio of B to A (B / A) is 0.8 to 1.2, and the ratio of C to A (C / A) is It is characterized by 0.5 to 1.2.

  The light emitting device according to claim 3 is the light emitting device according to claim 1 or 2, wherein the phosphor has a first phosphor having emission peaks at wavelengths of 490 to 510 nm and wavelengths of 530 to 580 nm, and a wavelength of 610 to 610, respectively. Each of the second phosphors having an emission peak at 660 nm is contained.

  The light-emitting device according to claim 4 is the light-emitting device according to claim 3, wherein the phosphor further contains a third phosphor having a light emission peak at a wavelength of 530 to 580 nm.

  The light-emitting device according to claim 5 is a blue light-emitting element that emits blue light; and is excited by the blue light emitted from the blue light-emitting element, and has emission peaks at wavelengths of 490 to 510 nm, 530 to 580 nm, and 610 to 660 nm, respectively. And having a valley of emission intensity at a wavelength of 470 to 490 nm due to color mixing with the blue light, and the ratio of the emission intensity of the valley to the emission intensity of the emission peak of the blue light is 0.7 to And a phosphor layer containing a phosphor that emits visible light of 0.9.

  The light emitting device according to claim 6 is the light emitting device according to claim 5, wherein the emission intensity of the emission peak at a wavelength of 490 to 510 nm in the emission spectrum of the phosphor is A, and the emission intensity of the emission peak at a wavelength of 530 to 580 nm is B. When the emission intensity of the emission peak at a wavelength of 610 to 660 nm is C, the ratio of B to A (B / A) is 0.8 to 1.2, and the ratio of C to A (C / A) is It is characterized by 0.5 to 1.2.

  The light-emitting device according to claim 7 is the light-emitting device according to claim 5 or 6, wherein the phosphor has a first phosphor having emission peaks at wavelengths of 490 to 510 nm and wavelengths of 530 to 580 nm, and a wavelength of 610 to 610, respectively. Each of the second phosphors having an emission peak at 660 nm is contained.

  The light-emitting device according to claim 8 is the light-emitting device according to claim 7, wherein the phosphor further contains a third phosphor having an emission peak at a wavelength of 530 to 580 nm.

  The light-emitting device according to claim 9 is the light-emitting device according to claim 7 or 8, wherein the phosphor has a half-value width of 125 to 145 nm of the emission peak at a wavelength of 490 to 510 nm and a half of the emission peak of a wavelength of 530 to 580 nm. The value width is 90 to 110 nm, and the half width of the emission peak at a wavelength of 610 to 660 nm is 80 to 100 nm.

  In the above-described inventions according to claims 1 to 9, the definitions and technical meanings of terms are as follows unless otherwise specified.

  A light emitting element that emits blue light emits blue light having a dominant wavelength of 420 to 480 nm (for example, 460 nm), and excites a phosphor with the emitted blue light to emit visible light. Examples of the light emitting element that emits blue light used in the present invention include, but are not limited to, a blue light emitting type LED chip.

  The phosphor is excited by blue light emitted from such a light emitting element to emit visible light, and a desired emission color as a light emitting device is obtained by mixing the visible light and the blue light emitted from the light emitting element. To get.

  In the present invention, the phosphor includes a first phosphor having emission intensity peaks (hereinafter referred to as emission peaks) in a wavelength range of 490 to 510 nm and a wavelength range of 530 to 580 nm, and a wavelength of 610 to 660 nm. A total of two types of phosphors, the second phosphor having an emission peak in the range, can be used. A first phosphor having an emission peak at wavelengths of 490 to 510 nm and a second phosphor having an emission peak at wavelengths of 610 to 660 nm together with a first phosphor having an emission peak at wavelengths of 490 to 510 nm and a wavelength of 530 to 580 nm. 3 phosphors can be contained. Further, three types of phosphors each having one emission peak in each wavelength range may be mixed and used. That is, fluorescence in which a first phosphor having a dominant wavelength (peak wavelength) of 490 to 510 nm, a second phosphor having a dominant wavelength of 530 to 580 nm, and a third phosphor having a dominant wavelength of 610 to 660 nm are mixed. The body can be used. The blending ratio of these two or three kinds of phosphors is adjusted so that the average color rendering index Ra of light emission from the light emitting device is high and high light emission efficiency is obtained.

  In the phosphor (phosphor mixture) in which the two or three kinds of phosphors are mixed, the emission peak intensity (emission intensity) in the wavelength range of 490 to 510 nm in the emission spectrum is A, and the emission is in the wavelength range of 530 to 580 nm. When the intensity of the peak is B and the intensity of the emission peak in the wavelength range of 610 to 660 nm is C, the ratio of B to A (B / A) is 0.8 to 1.2, and the ratio of C to A (C / A) is preferably 0.5 to 1.2.

  In the phosphor of the present invention, the emission peak at a wavelength of 490 to 510 nm preferably has a half width of 125 to 145 nm, and the emission peak of a wavelength of 530 to 580 nm preferably has a half width of 90 to 110 nm. Similarly, the emission peak at a wavelength of 610 to 660 nm preferably has a half width of 80 to 100 nm. Note that the half-width at the emission peak of the phosphor refers to the spread width (wavelength) of the spectrum at half the intensity of the emission peak.

  Further, in the present invention, by using the above-described two or three kinds of phosphors, there is a valley portion of emission intensity at a wavelength of 470 to 490 nm due to color mixture with blue light emitted from the blue light emitting element. Light is emitted so that the ratio (D / E) of the emission intensity of the valley (denoted as D) to the intensity of the emission peak of blue light (denoted as E) is 0.7 to 0.9. Can be configured.

  The phosphor layer containing the phosphor is formed as a layer obtained by mixing and dispersing the two or three kinds of phosphors in addition to a transparent resin such as a silicone resin or an epoxy resin. Although it can be formed so as to cover the outside of the light emitting element, a transparent resin layer is formed so as to directly cover the light emitting element, and a layer containing the two or three kinds of phosphors described above may be provided thereon. Is possible.

  According to the light emitting device of claims 1 and 3, the emission spectrum from the phosphor has an emission peak in the wavelength range of 530 to 580 nm and an emission peak in the wavelength range of 610 to 660 nm as well as in the wavelength range of 490 to 510 nm. Since it has an emission peak, light emission with high color rendering can be obtained. Moreover, even if the blending amount of the red phosphor having a dominant wavelength of 610 to 660 nm is reduced, high color rendering properties can be obtained, and an improvement in luminous efficiency can be achieved by reducing the amount of red phosphor.

  According to the light emitting device of claim 2, light emission which is a demerit due to the blending of the red phosphor while realizing an improvement in color rendering by adjusting the intensity of the emission peak in each wavelength range in the emission spectrum of the phosphor. The reduction in efficiency can be suppressed as much as possible, and high color rendering properties and high luminous efficiency can be obtained.

  According to the light emitting device of the fourth aspect, it is possible to obtain light emission with high color rendering properties and higher light emission efficiency.

  According to the light emitting device of claim 5, the light emitted by the color mixture of the blue light emitted from the blue light emitting element and the visible light excited by the blue light and emitted from the phosphor has a wavelength of 470 to 490 nm. And has a spectrum in which the ratio of the emission intensity (D) in the valley to the emission intensity (E) of the emission peak of the blue light is 0.7 to 0.9. Therefore, energy efficiency can be improved while suppressing a decrease in the average color rendering index Ra, and light emission with high color rendering properties and high light emission efficiency can be obtained. That is, when the ratio is less than 0.7, the average color rendering index Ra starts to decrease, and when the ratio exceeds 0.9, light with a wavelength of 470 to 490 nm has low visibility, Even if the emission intensity is high, the visual effect is small, so that the energy efficiency is lowered and the emission efficiency cannot be increased.

  According to the light emitting device of the sixth to eighth aspects, the average color rendering index Ra can be further improved, the energy efficiency can be improved, and the light emission efficiency can be increased.

  According to the light emitting device of the ninth aspect, high color rendering can be realized while maintaining high luminous efficiency.

  Therefore, according to the present invention, it is possible to provide a light emitting device capable of improving the average color rendering index Ra while improving the light emission efficiency as compared with the prior art.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration of an embodiment in which the light-emitting device of the present invention is applied to an LED lamp. FIG. 2 is a diagram of a plurality of LED lamps shown in FIG. FIG. 3 is a cross-sectional view taken along the line AA ′ of FIG. 2.

  The LED lamp 1 shown in FIG. 1 has a blue light emitting type LED chip 2 as a light emitting element. The LED chip 2 is mounted on a substrate 4 having a circuit pattern 3. As the substrate 4, a flat plate made of aluminum (Al), nickel (Ni), glass epoxy resin or the like having heat dissipation and rigidity is used, and a cathode side and an anode side are disposed on the substrate 4 through an electric insulating layer 5. Circuit patterns 3 are respectively formed. The circuit pattern 3 is made of an alloy of Cu and Ni, Au, or the like.

  The bottom electrode of the LED chip 2 is disposed on and electrically connected to the circuit pattern 3 on one electrode side, and the bonding electrode 6 such as a gold wire is connected to the circuit pattern 3 on the other electrode side. It is electrically connected via. As an electrode connection structure of the LED chip 2, a flip chip connection structure can also be applied. According to these electrode connection structures, the light extraction efficiency to the front surface of the LED chip 2 is improved.

  On the substrate 4, a frame 8 made of resin or the like having a recess 7 is provided. The frame 8 having the recess 7 is made of a synthetic resin such as PBT (polybutylene terephthalate), PPA (polyphthalamide), PC (polycarbonate), etc., and the LED chip 2 is disposed and accommodated in the recess 7. . And in the recessed part 7 in which LED chip 2 was accommodated, the 1st fluorescent substance (green fluorescent substance) which has a light emission peak in the range of wavelength 490-510 nm and the range of wavelength 530-580 nm, respectively, wavelength 610-660 nm The LED chip 2 is coated and filled with a phosphor-containing resin in which a total of two types of phosphors, a second phosphor (red phosphor) having a light emission peak in the range of, is mixed and dispersed in a transparent resin. Is covered with such a phosphor-containing resin layer 9. As the transparent resin, for example, a silicone resin or an epoxy resin is used.

  As a phosphor, a yellow phosphor (third phosphor) having an emission peak in the wavelength range of 530 to 580 nm, together with the green phosphor as the first phosphor and the red phosphor as the second phosphor. These three types of phosphors can be mixed and used.

The green phosphor is, for example, a YAG phosphor such as RE ₃ (Al, Ga) ₅ O ₁₂ : Ce phosphor (RE represents at least one selected from Y, Gd and La), AE ₂ SiO ₄ : Eu phosphors (AE represents alkaline earth elements such as Sr, Ba, Ca) and silicate phosphors such as Ca ₃ Sc ₂ Si ₃ O ₁₂ : Ce phosphors, sialon phosphors (for example, Ca _x Si _y Al _z ON: Eu ²⁺ ), Ca ₃ Sc ₂ O ₄ : Ce phosphor, and the like.

Examples of the red phosphor include oxysulfide phosphors such as La ₂ O ₂ S: Eu phosphor, nitride phosphors (for example, AE ₂ Si ₅ N ₈ : Eu ²⁺ and CaAlSiN ₃ : Eu ²⁺ ), and the like. Although used, it is not particularly limited.

The yellow phosphor is, for example, a YAG phosphor such as RE ₃ (Al, Ga) ₅ O ₁₂ : Ce phosphor (RE represents at least one selected from Y, Gd and La), (Tb, Al) ₅ O ₁₂ : TAG phosphor such as Ce phosphor, sialon-based phosphor (for example, Ca _x Si _y Al _z ON: Eu ²⁺ ), AE ₂ SiO ₄ : Eu phosphor (AE is Sr, Ba, Ca, etc.) Silicate phosphors such as Sr ₃ SiO ₅ : Eu ²⁺ phosphor and the like.

  And the mixture of the fluorescent substance which consists of these 2 types or 3 types of fluorescent substance has the emission spectrum shown below. That is, when the emission peak intensity in the wavelength range of 490 to 510 nm of the emission spectrum is A, the emission peak intensity in the wavelength range of 530 to 580 nm is B, and the emission peak intensity in the wavelength range of 610 to 660 nm is C, The ratio of B and A (B / A) is 0.8 to 1.2, and the ratio of C and A (C / A) is 0.5 to 1.2.

  When the ratio of B to A (B / A) exceeds 1.2, or the ratio of C to A (C / A) exceeds 1.2, the average color rendering index Ra is improved and high color rendering is obtained. However, the luminous efficiency is undesirably low. Conversely, when the ratio of B to A (B / A) is less than 0.8, or the ratio of C to A (C / A) is less than 0.5, the color temperature of light emission is adjusted. It is hard to cope with.

  The preferred half-widths of the emission peaks of these phosphors are 125 to 145 nm for the emission peak at a wavelength of 490 to 510 nm, 90 to 110 nm for the emission peak of a wavelength of 530 to 580 nm, and 80 for the emission peak of a wavelength of 610 to 660 nm. It is preferable to set it to ˜100 nm. When a phosphor having a broad emission peak whose half width is out of the above range or an emission peak that is too sharp is used, it is difficult to obtain light with high efficiency and high color rendering properties. That is, in any light emission peak in any wavelength range, in the case of a light emission peak whose half width is less than the lower limit value and is too sharp, the average color rendering index Ra is too low. Moreover, in the emission peak of wavelength 530-580 nm, when it is set as the broad emission peak whose half value width exceeds 110 nm, luminous efficiency becomes low and is not preferable. In the light emission peak at a wavelength of 490 to 510 nm and the light emission peak at a wavelength of 610 to 660 nm, in the case of a broad light emission peak whose half width exceeds the upper limit, since the light emission is relatively low in visibility, the decrease in light emission efficiency is not so much. Although it is not large, the effect of improving color rendering is not sufficiently improved.

  In the LED lamp 1 of the embodiment, the applied electrical energy is converted and emitted by the LED chip 2 into blue light having a dominant wavelength of 420 to 480 nm (for example, 460 nm), and the emitted blue light is emitted from the phosphor-containing resin layer. 9 is a phosphor composed of a total of two types of green phosphors and red phosphors, or a total of three types of green phosphors, yellow phosphors, and red phosphors, and is converted into light having a longer wavelength. And the white light which is a color based on the blue light radiated | emitted from LED chip 2, and the luminescent color of these fluorescent substance is discharge | released from the LED lamp 1. FIG.

  In the LED lamp 1 of the embodiment, since light having a dominant wavelength of 490 to 510 nm, which was not present in the emission spectrum of the conventional LED lamp 1, is added, the sufficiently high average color rendering index Ra In addition to ensuring the value, the color rendering property is favorable. In addition, since the blending ratio of the phosphor (red phosphor) having a main wavelength of 610 to 660 nm necessary for obtaining a desired color temperature can be reduced as compared with the conventional one, the luminous efficiency can be improved. . In other words, by reducing the blending ratio of the red phosphor, while maintaining a sufficiently high color rendering property, it is possible to suppress a decrease in light emission efficiency, which is a demerit due to the blending of the red phosphor, resulting in high color rendering properties and high light emission. Efficiency can be achieved simultaneously.

  In addition, the light emitted by the color mixture of the blue light emitted from the blue light emitting element and the light emitted from the phosphor has a valley portion of the emission intensity in the wavelength range of 470 to 490 nm, and in this valley portion The light emission intensity (D) has a spectrum such that the ratio is 0.7 to 0.95 with respect to the light emission intensity (A) of the light emission peak in the wavelength range of 490 to 510 nm. As described above, a valley of emission intensity is formed in the wavelength range with low visibility (470 to 490 nm), and the light emission spectrum has been converted into a wavelength range with higher visibility (for example, 490 to 510 nm). Therefore, the luminous efficiency is improved. In addition, when the ratio (D / E) of the emission intensity (D) of the emission valley portion to the emission intensity (E) of the emission peak of blue light is less than 0.7, it is preferable because the average color rendering index Ra is significantly reduced. Absent. The light in the trough wavelength range (470 to 490 nm) has low visibility, and the visual effect is small even when the emission intensity is high. Therefore, when D / E exceeds 0.9, the emission efficiency is improved. Is not preferable in terms of energy efficiency.

  In the above embodiment, the LED module 21 in which a plurality of LED lamps 1 are arranged in a matrix has been described. However, the present invention is not limited to this, and for example, a plurality of LED lamps 1 are arranged in a row. The LED lamps 1 may be formed in a single arrangement.

  4 and 5 show a light-emitting device for forming an LED package according to the second embodiment of the present invention. 4 is a plan view of the light emitting device, and FIG. 5 is a longitudinal sectional view of the light emitting device shown in FIG. 4 cut along the line FF. 4 and 5, the same reference numerals are used for the same components as those in the drawings relating to the first embodiment, and the description thereof is simplified or omitted.

  A light emitting device (LED lamp) 1 shown in FIGS. 4 and 5 includes a package substrate such as a device substrate 4, a reflective layer 31, a circuit pattern 3, and preferably a plurality of semiconductor light emitting elements (such as blue LED chips) 2. The adhesive layer 32, the reflector 34, the phosphor-containing resin layer 9, and the light diffusion member 33 are formed. The phosphor-containing resin layer 9 also functions as a sealing member.

  The device substrate 4 is made of a flat plate made of a metal or an insulating material such as a synthetic resin, and has a predetermined shape such as a rectangular shape in order to obtain a light emitting area required for the light emitting device 1. When the device substrate 4 is made of a synthetic resin, it can be formed of, for example, an epoxy resin containing glass powder. When the device substrate 4 is made of metal, the heat radiation from the back surface of the device substrate 4 is improved, the temperature of each part of the device substrate 4 can be made uniform, and the semiconductor light emitting element 2 that emits light in the same wavelength range. The variation in the emission color can be suppressed. In addition, as a metal material which has such an effect, the material excellent in the heat conductivity of 10 W / m * K or more, specifically, aluminum or its alloy can be illustrated.

  The reflective layer 31 is sized so that a predetermined number of semiconductor light emitting elements 2 can be disposed, and is, for example, attached to the entire surface of the device substrate 4. The reflective layer 31 can be made of a white insulating material having a reflectance of 85% or more in the wavelength region of 400 to 740 nm. As such a white insulating material, a prepreg made of an adhesive sheet can be used. Such a prepreg can be formed, for example, by impregnating a sheet base material with a thermosetting resin mixed with a white powder such as aluminum oxide. The reflective layer 31 is bonded to the entire surface of the device substrate 4 by its own adhesiveness.

  The circuit pattern 3 is bonded to a surface of the reflective layer 31 opposite to the surface to which the device substrate 4 is bonded as an energizing element for each semiconductor light emitting element 2. The circuit pattern 3 is formed in two rows dotted at predetermined intervals in the longitudinal direction of the device substrate 4 and the reflective layer 31 in order to connect the semiconductor light emitting elements 2 in series, for example. The end-side circuit pattern 3a located on one end side of the row of one circuit pattern 3 is integrally formed with a power feeding pattern portion 3c. Similarly, the end located on one end side of the row of the other circuit pattern 3 The side circuit pattern 3a is integrally formed with a power feeding pattern portion 3d.

  The power feeding pattern portions 3 c and 3 d are provided side by side at one end in the longitudinal direction of the reflective layer 31, and are separated from each other and insulated by the reflective layer 31. An electric wire (not shown) reaching the power source is individually connected to each of the power supply pattern portions 3c and 3d by soldering or the like.

  The circuit pattern 3 is formed by the procedure described below. First, a reflective layer 31 made of a prepreg impregnated with the uncured thermosetting resin is pasted on the device substrate 4, and then a copper foil of the same size is pasted on the reflective layer 31. Next, the laminated body thus obtained is heated and pressurized to cure the thermosetting resin, whereby the device substrate 4 and the copper foil are pressed against the reflective layer 31 to complete the adhesion. Next, after providing a resist layer on the copper foil and etching the copper foil, the remaining resist layer is removed to form the circuit pattern 3. The thickness of the circuit pattern 3 made of copper foil is, for example, 35 μm.

  As shown in FIG. 5, the semiconductor light emitting device 2 is formed of a double wire type LED chip using, for example, a nitride semiconductor, and is formed by laminating a semiconductor light emitting layer 2a on one surface of a light transmitting element substrate 2b. ing. The element substrate 2b is made of, for example, a sapphire substrate. The element substrate 2b is thicker than the circuit pattern 3, for example, 90 μm.

  The semiconductor light emitting layer 2a is formed by sequentially stacking a buffer layer, an n-type semiconductor layer, a light emitting layer, a p-type cladding layer, and a p-type semiconductor layer on the main surface of the element substrate 2b. The light emitting layer has a quantum well structure in which barrier layers and well layers are alternately stacked. An n-side electrode is provided on the n-type semiconductor layer, and a p-side electrode is provided on the p-type semiconductor layer. This semiconductor light emitting layer 2a does not have a reflective film, and can emit light in both thickness directions.

  Each semiconductor light emitting element 2 is disposed between circuit patterns 3 adjacent to each other in the longitudinal direction of the device substrate 4, and is bonded to the same surface of the white reflective layer 31 by an adhesive layer 32. Specifically, the other surface parallel to one surface of the element substrate 2 b on which the semiconductor light emitting layer 2 a is laminated is bonded to the reflective layer 31 by the adhesive layer 32. By this adhesion, the circuit pattern 3 and the semiconductor light emitting element 2 are arranged in a straight line on the same surface of the reflective layer 31. Therefore, the side surface of the semiconductor light emitting element 2 positioned in this arrangement direction and the circuit pattern 3 are close to each other. It is provided so as to face each other.

  The thickness of the adhesive layer 32 can be, for example, 5 μm or less. For the adhesive layer 32, for example, a translucent adhesive having a thickness of 5 μm or less and a light transmittance of 70% or more, for example, a silicone resin-based adhesive can be suitably used.

  As shown in FIGS. 4 and 5, the electrode of each semiconductor light emitting element 2 and the circuit pattern 3 disposed in proximity to both sides of the semiconductor light emitting element 2 are connected by bonding wires 6. Further, the end-side circuit patterns 3b positioned on the other end side of the two rows of circuit patterns 3 rows are also connected by bonding wires 6. Therefore, in this embodiment, each semiconductor light emitting element 2 is connected in series.

  The surface light source of the light emitting device 1 is formed by the device substrate 4, the reflective layer 31, the circuit pattern 3, each semiconductor light emitting element 2, the adhesive layer 32, and the bonding wire 6.

  The reflector 34 is not individually provided for each one or several semiconductor light emitting elements 2, but is a single one that surrounds all the semiconductor light emitting elements 2 on the reflective layer 31, and has a rectangular frame, for example. Thus, the semiconductor light emitting element 2 is disposed in the recess 7 formed by the frame. The reflector 34 is bonded to the reflective layer 31, and a plurality of semiconductor light emitting elements 2 and circuit patterns 3 are housed therein, and the pair of power feeding pattern portions 3 c and 3 d are positioned outside the reflector 34. ing.

  The reflector 34 can be formed of, for example, a synthetic resin, and its inner peripheral surface is a reflective surface. The reflecting surface of the reflector 34 can be formed by vapor deposition or plating of a metal material having a high reflectance such as Al or Ni, or can be formed by applying a white paint having a high visible light reflectance. Alternatively, white powder can be mixed into the molding material of the reflector 34 to make the reflector 34 itself white with high visible light reflectivity. As the white powder, a white filler such as aluminum oxide, titanium oxide, magnesium oxide or barium sulfate can be used. In addition, it is desirable to form the reflecting surface of the reflector 34 so as to gradually open in the irradiation direction of the light emitting device 1.

  As in the first embodiment, the phosphor-containing resin layer 9 is formed by using a liquid thermosetting resin in which two or three kinds of phosphors are mixed using an injection device such as a dispenser and the surface of the reflective layer 31 and The semiconductor light-emitting elements 2 and the bonding wires 6 arranged in a straight line are filled so as to be evenly filled, and the thermosetting resin is cured by heating.

  The liquid transparent resin that flows between the surface of the reflective layer 31 and the bonding wire 6 reaches each semiconductor light emitting element 2 and the bonding wire 6 due to a capillary phenomenon or the like, and the film thickness thereof is almost uniform. The body is also almost uniformly dispersed in the transparent resin.

  Also in the second embodiment configured as described above, a sufficiently high value of the average color rendering index Ra can be ensured, and preferable color rendering properties are provided. In addition, energy efficiency can be improved and high luminous efficiency can be obtained.

  Next, examples of the present invention and evaluation results thereof will be described.

Examples 1 and 2 and Comparative Examples Table 1 shows green phosphors (YAG phosphors) each having an emission peak at a wavelength of 500 nm and a wavelength of 550 nm, and red phosphors having an emission peak at a wavelength of 650 nm. The mixture was mixed and dispersed at the indicated blending ratio (blending ratio with respect to the silicone resin; wt%). In Example 2, the compounding ratio of the red phosphor having a dominant wavelength of 650 nm was decreased as compared with Example 1. Further, in the comparative example, a yellow phosphor having a light emission peak at a wavelength of 540 nm (YAG phosphor) is used, and this phosphor and a red phosphor having a dominant wavelength of 650 nm are mixed with a silicone resin at a blending ratio shown in Table 1. Mixed in and dispersed.

  Next, after filling the phosphor-containing silicone resin thus obtained into the recess 8 having an opening diameter of 3 mm, the silicone resin is cured to form the phosphor-containing resin layer 9, and the LED having the configuration shown in FIG. A lamp 1 was produced. The optical path length of the phosphor-containing resin layer 9 was 0.45 mm. The optical path length refers to the thickness of the phosphor-containing resin layer on the light extraction side from the upper surface of the LED chip.

  Thus, the LED lamps obtained in Examples 1 and 2 and the comparative example were caused to emit light, and the color temperature of light emission, the average color rendering index Ra, and the light emission efficiency were measured, respectively. These measurement results are shown in Table 1. The luminous efficiency is a relative value when the luminous efficiency of the LED lamp of the comparative example is 100%.

  The emission spectra of these LED lamps were measured using a spectrophotometer (instant spectrophotometer MCPD-7000 manufactured by Otsuka Electronics). Then, the intensity A of the emission peak at the wavelength of 500 nm, the intensity B of the emission peak at the wavelength of 550 nm, and the intensity C of the emission peak at the wavelength of 650 nm are measured, respectively, and the ratio of B to A (B / A) and the ratio of C to A ( C / A) was determined. These results are shown in Table 1. Furthermore, the emission spectrum of the LED lamp obtained in Example 2 and the comparative example is shown in FIG.

  As is apparent from Table 1, the LED lamps obtained in Example 1 and Example 2 contain a phosphor having an emission peak at a wavelength of 550 nm and an emission peak at a wavelength of 650 nm, and also having an emission peak in the vicinity of a wavelength of 500 nm. Therefore, light emission with high color rendering properties can be obtained, and the average color rendering index Ra can be improved.

  In particular, as can be seen from the emission spectrum of FIG. 6, the LED lamp obtained in Example 2 has a valley of emission intensity in a wavelength range of 470 to 490 nm (480 nm) with low visibility, and this valley ( The ratio of the emission intensity (D) at the wavelength 480 nm) to the emission intensity (E) of the emission peak of blue light (wavelength 460 nm) is 0.85. And although the LED lamp of Example 2 has the color temperature similar to the LED lamp of Example 1 and a comparative example, average color rendering index Ra is 92 and has higher color rendering than the LED lamp of a comparative example. Have. In addition, the luminous efficiency is 30% higher than that of Example 1, and the luminous efficiency is extremely high. On the other hand, the emission spectrum of the LED lamp of the comparative example does not have a valley of emission intensity in the wavelength range of 470 to 490 nm (480 nm), and both the average color rendering index Ra and the emission efficiency are from Example 2. It is low.

Examples 3-12
In Examples 3 to 6, two types of phosphors were used: a green phosphor having an emission peak at a wavelength of 500 nm and a wavelength of 550 nm (YAG phosphor) and a red phosphor having an emission peak at a wavelength of 650 nm. In Examples 7 to 12, a yellow phosphor having an emission peak at a wavelength of 565 nm (YAG phosphor) is added to the green phosphor (YAG phosphor) and the red phosphor, and a total of three types of phosphors are obtained. used. Each of these phosphors was mixed and dispersed in the silicone resin at a blending ratio shown in Table 2 (blending ratio with respect to the silicone resin: wt%).

  Next, after the phosphor-containing silicone resin thus obtained was filled into the recess 8 having an opening diameter of 3 mm, as in Examples 1 and 2, the silicone resin was cured to form the phosphor-containing resin layer 9. An LED lamp 1 having the configuration shown in FIG. 1 was produced. In Examples 3 to 12, since the blending ratio of the phosphor to the resin was made smaller than in Examples 1 and 2, in order to achieve the same color, the optical path length of the phosphor-containing resin layer 9 was The length was as long as 0.9 mm. In order to make the emission color and the emission intensity equal, it is necessary to make the product of the optical path length and the blending ratio of the phosphors equal.

  Thus, the LED lamps obtained in Examples 3 to 12 were caused to emit light, and the color temperature of light emission, the average color rendering index Ra, and the light emission efficiency were measured. These measurement results are shown in Table 2. The luminous efficiency is a relative value when the luminous efficiency of the LED lamp of Example 7 is 100%.

  The emission spectrum was measured using a spectrophotometer (instant spectrophotometer MCPD-7000 manufactured by Otsuka Electronics Co., Ltd.). Of these spectra, the emission spectrum of the LED lamp obtained in Example 4 is shown in FIG. 7, the emission spectrum of the LED lamp obtained in Example 6 is shown in FIG. 8, and the emission spectrum of the LED lamp obtained in Example 8 is shown. FIG. 9 shows the emission spectrum, FIG. 10 shows the emission spectrum of the LED lamp obtained in Example 9, FIG. 11 shows the emission spectrum of the LED lamp obtained in Example 11, and FIG. 11 shows the LED lamp obtained in Example 12. The emission spectra are shown in FIG.

  Furthermore, from the emission spectrum of these LED lamps, the ratio of the emission intensity (D) at the valley in the wavelength range of 470 to 490 nm (for example, 480 nm) to the emission intensity (E) at the wavelength of 460 nm (valley intensity ratio D / E). Asked. These results are also shown in Table 2.

  From the measurement results of Table 2 and the emission spectra of FIGS. That is, the LED lamps obtained in Examples 3 to 12 have emission peaks near the wavelength of 550 nm and near the wavelength of 650 nm, respectively, and also have emission peaks near the wavelength of 500 nm, and the average color rendering index Ra is high. And has a sufficiently high luminous efficiency.

  Further, as can be seen from the emission spectra of the LED lamps obtained in Examples 4, 6, 8.9, 11, 12 and Example 2, the valley intensity ratio (D / E) is 0.7 to 0.9. In this case, particularly at a color temperature of 3000 to 4000 K, the average color rendering index Ra is as high as 90 or more, which is suitable as an LED lamp. In addition, in the LED lamps of Examples 3 to 6 using two types of phosphors, a green phosphor and a red phosphor, the luminous efficiency is not so high, but the average color rendering index Ra is as high as 90 to 95. Luminescence having color rendering properties can be obtained. On the other hand, in the LED lamps of Examples 7 to 12 using a total of three types of phosphors, that is, a green phosphor, a red phosphor, and a yellow phosphor, even if the average color rendering index Ra is about 80, Luminescence having high luminous efficiency can be obtained.

It is sectional drawing which shows the structure of 1st Embodiment which applied the light-emitting device of this invention to the LED lamp. It is a top view which shows an example of the LED module which has arrange | positioned two or more LED lamps shown in FIG. FIG. 3 is a cross-sectional view taken along line AA ′ in FIG. 2. It is a top view of the light-emitting device concerning 2nd Embodiment of the light-emitting device of this invention. It is the FF sectional view taken on the line of FIG. It is a graph which shows the emission spectrum of the LED lamp obtained by Example 2 and the comparative example of this invention. It is a graph which shows the emission spectrum of the LED lamp obtained in Example 4 of this invention. It is a graph which shows the emission spectrum of the LED lamp obtained in Example 6 of this invention. It is a graph which shows the emission spectrum of the LED lamp obtained in Example 8 of this invention. It is a graph which shows the emission spectrum of the LED lamp obtained in Example 9 of this invention. It is a graph which shows the emission spectrum of the LED lamp obtained in Example 11 of this invention. It is a graph which shows the emission spectrum of the LED lamp obtained in Example 12 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... LED lamp, 2 ... LED chip, 3 ... Circuit pattern, 4 ... Board | substrate, 6 ... Bonding wire, 7 ... Recessed part, 8 ... Frame, 9 ... Phosphor containing resin layer.

Claims (9)

A light emitting device emitting blue light;
A phosphor layer containing a phosphor that is excited by blue light emitted from the light emitting element and emits light having peaks at wavelengths of 490 to 510 nm, 530 to 580 nm, and 610 to 660 nm;
A light-emitting device comprising:   When the emission intensity of the emission peak at a wavelength of 490 to 510 nm in the emission spectrum of the phosphor is A, the emission intensity of the emission peak at a wavelength of 530 to 580 nm is B, and the emission intensity of the emission peak at a wavelength of 610 to 660 nm is C. The ratio of B to A (B / A) is 0.8 to 1.2, and the ratio of C to A (C / A) is 0.5 to 1.2. Light-emitting device.   The phosphor includes a first phosphor having an emission peak at a wavelength of 490 to 510 nm and a wavelength of 530 to 580 nm, and a second phosphor having an emission peak at a wavelength of 610 to 660 nm, respectively. The light-emitting device according to claim 1.   4. The light emitting device according to claim 3, wherein the phosphor further contains a third phosphor having a light emission peak at a wavelength of 530 to 580 nm. A blue light emitting element emitting blue light;
Excited by blue light emitted from the blue light emitting element, has emission peaks at wavelengths of 490 to 510 nm, 530 to 580 nm, and 610 to 660 nm, respectively, and the emission intensity at wavelengths of 470 to 490 nm due to color mixture with the blue light. And a phosphor layer containing a phosphor that emits visible light, the ratio of the emission intensity of the valley to the emission intensity of the emission peak of the blue light being 0.7 to 0.9;
A light-emitting device comprising:   When the emission intensity of the emission peak at a wavelength of 490 to 510 nm in the emission spectrum of the phosphor is A, the emission intensity of the emission peak at a wavelength of 530 to 580 nm is B, and the emission intensity of the emission peak at a wavelength of 610 to 660 nm is C. 6. The ratio of B to A (B / A) is 0.8 to 1.2, and the ratio of C to A (C / A) is 0.5 to 1.2. Light-emitting device.   The phosphor includes a first phosphor having an emission peak at a wavelength of 490 to 510 nm and a wavelength of 530 to 580 nm, and a second phosphor having an emission peak at a wavelength of 610 to 660 nm, respectively. The light emitting device according to claim 5 or 6.   8. The light emitting device according to claim 7, wherein the phosphor further contains a third phosphor having a light emission peak at a wavelength of 530 to 580 nm.   In the phosphor, the half width of the emission peak at a wavelength of 490 to 510 nm is 125 to 145 nm, the half width of the emission peak at a wavelength of 530 to 580 nm is 90 to 110 nm, and the half width of the emission peak at a wavelength of 610 to 660 nm is The light-emitting device according to claim 7 or 8, wherein the light-emitting device has a thickness of 80 to 100 nm.

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