JP2018129450A - White light source and LED lighting device - Google Patents

Abstract

A blue LED element having an excitation light source and a fluorescent member and having a single emission peak with a wavelength of 440 nm or more and 465 nm or less, and a wavelength longer than the single emission peak of the blue LED element by 10 nm or more and 480 nm. A blue-green LED element having a single emission peak, and the fluorescent member includes a phosphor that is excited by excitation light from the LED element and emits light having a longer wavelength than the excitation light, and an emission color temperature A remote phosphor type white light source with a 3500K or higher. [Effect] It is possible to provide a white light source and an LED lighting device that are excellent in color rendering, stably and easily, while ensuring a blue-green component in a light-emitting component. [Selection] Figure 3

Description

  The present invention relates to a white light source and an LED illumination device having excellent color rendering properties.

  A white light source using an LED (white LED) has a luminous efficiency that is five times higher than that of an incandescent light bulb that has been widely used, and does not use harmful mercury unlike fluorescent lamps. However, the illumination using white LEDs is becoming mainstream illumination, but its color rendering is not sufficient compared to incandescent bulbs.

JP 2006-245443 A

  A general white LED package is composed of a blue LED element and a phosphor that converts excitation light emitted from the blue LED element into a longer-wavelength visible light component. This phosphor absorbs incident blue excitation light and emits longer wavelength fluorescence. Excitation light that has not been absorbed by the phosphor is used as a blue light component of white light. When the wavelength of blue light used as excitation light is shorter than 440 nm, the wavelength is out of the visible light range, and when longer than 460 nm, the short wavelength component in the emission spectrum of the white LED, that is, the blue component is small, Since the bluish color of the luminescent color is insufficient, it is not preferable. For this reason, in general, white light uses blue light having a wavelength of 440 to 465 nm as excitation light.

  In white LEDs, when the wavelength of excitation light from a blue LED element is converted by a phosphor, it is difficult to obtain fluorescence having a wavelength close to that of the excitation light, and the fluorescence peak is 50 nm or more longer than the excitation light from the blue LED element. Wavelength. Therefore, in the light emission of a white LED that combines excitation light and fluorescence, the intermediate wavelength component between the emission peaks of excitation light and fluorescence is insufficient, resulting in a blue-green light deficient region (so-called green valley). , The light is slightly inferior in color rendering.

  As a countermeasure, it is conceivable to compensate for light in the wavelength deficient region by combining light emission of the white LED light source with blue-green light emission having a light emission peak at a wavelength of 450 to 500 nm. However, by simply combining the light emission of the blue-green LED package with white light, the short-wavelength component in the emission spectrum of the illumination light becomes excessive, so that the light emission becomes green and does not result in high color rendering white light emission. In white LED lighting, when trying to obtain a good color rendering property by combining a blue-green LED package, the white LED has a special spectrum spectrum, such as increasing the long-wavelength emission component on the premise that blue-green light is added. It is necessary to emit white light with adjusted.

  For example, Japanese Patent Laid-Open No. 2006-245443 (Patent Document 1) discloses a phosphor-dispersed resin-coated LED in which a phosphor is dispersed and coated in a resin that seals a blue light-emitting LED element and a green light-emitting LED element. An illumination that combines a package is disclosed. In the manufacture of such a phosphor-dispersed resin-coated LED package, there are variations in the light emission characteristics of the obtained LED packages, and it is technically difficult to obtain only those having specific light emission characteristics with good yield. Japanese Patent Laid-Open No. 2006-245443 (Patent Document 1) discloses a method for obtaining light having a desired color rendering property as a whole by adjusting the illuminance by providing a driver circuit for each LED package. Has been. Although this method can adjust the emission color by adjusting the applied current even when using an LED package with a large variation in chromaticity, it is mechanically complex and in order to obtain white light with good color rendering properties. After lighting manufacture, it is essential to adjust the amount of light for each LED package by measuring the color rendering properties. In addition, in an LED package based on such a combination, the emission spectrum and chromaticity of the individual LED package to be used are different from those of a general-purpose white LED, so that it is difficult to divert as a conventional product. Since the manufacture of such a special white LED package is expensive compared to the manufacture of a highly versatile white LED package, it is not considered industrially realistic.

  The present invention has been made in view of the above circumstances, and aims to stably and easily provide a white light source and an LED lighting device having excellent color rendering properties while ensuring a blue-green component in a light-emitting component. And

As a result of intensive studies in order to solve the above problems, the present inventors have converted a white light source suitable as an illuminating device, an excitation light source including a plurality of LED elements, and a wavelength of excitation light from the LED elements. As a member, it is provided in front of the light emission direction of the excitation light source, separated from the excitation light source via a vacuum layer or a gas layer, and excited by excitation light from the LED element to emit light having a wavelength longer than that of the excitation light. Remote equipped with a phosphor, for example, a phosphor that emits light of yellow or green wavelength, or a phosphor that emits light of yellow or green wavelength and a phosphor that emits light of red wavelength A blue LED element having a single emission peak with a wavelength of 440 nm or more and 465 nm or less and a single emission of the blue LED element as a plurality of LED elements of the excitation light source with a phosphor system And a blue-green LED element having a single emission peak that is 10 nm or longer and 480 nm or less than the peak, and configured to have an emission color temperature of 3500 K or more, preferably the wavelength of the emission spectrum to 500nm below the range of 400 nm, having a plurality of peaks derived from the emission peak of the excitation light source, among the plurality of peaks, the most the peak of the energy intensity of the short wavelength side (E _S), the peak of residual By configuring the ratio (E _S / E _L ) with the maximum peak energy intensity (E _L ) to be 0.8 or more, high color rendering can be achieved stably and easily to compensate for the shortage of the green component. The inventors have found that a white light having a property can be obtained, and have reached the present invention.

Accordingly, the present invention provides the following white light source and LED illumination device.
Claim 1:
A remote phosphor type white light source comprising: an excitation light source including a plurality of LED elements; and a fluorescent member provided in front of a light emission direction of the excitation light source and spaced apart from the excitation light source via a vacuum layer or a gas layer Because
The plurality of LED elements of the excitation light source have a blue LED element having a single emission peak with a wavelength of 440 nm or more and 465 nm or less, and the wavelength is 10 nm or more longer than the single emission peak of the blue LED element and 480 nm or less. A blue-green LED element having a single emission peak, and the fluorescent member includes a phosphor that is excited by excitation light from the LED element and emits light having a longer wavelength than the excitation light, and emitting color A white light source having a temperature of 3500K or higher.
Claim 2:
It has a plurality of peaks in the wavelength range of 400 nm to 500 nm of the emission spectrum, and among the plurality of peaks, the energy intensity (E _S ) of the shortest wavelength side peak and the maximum peak among the remaining peaks 2. The white light source according to claim 1, wherein a ratio (E _S / E _L ) to the energy intensity (E _L ) is 0.8 or more.
Claim 3:
The white light source according to claim 1 or 2, wherein the excitation light source includes one or more LED packages in which one or more of the LED elements are sealed with a transparent material or a translucent material.
Claim 4:
The white light source according to any one of claims 1 to 3, wherein the fluorescent member is obtained by dispersing the phosphor on the particles in an inorganic or organic transparent material or translucent material.
Claim 5:
The phosphor is excited by blue to blue-green light having a wavelength of 440 nm to 465 nm, or emits light having a yellow or green wavelength, or the phosphor and blue to blue-green light having a wavelength of 440 nm to 465 nm 5. The white light source according to claim 1, wherein the white light source includes a phosphor that emits light having a red wavelength when excited by.
Claim 6:
The phosphor emitting light of yellow or green wavelength includes a cerium activated yttrium aluminum garnet phosphor and / or a cerium activated lutetium aluminum garnet phosphor, and the phosphor emitting light of the red wavelength is manganese activated. The white light source according to claim 5, comprising potassium silicofluoride.
Claim 7:
An LED lighting device comprising the white light source according to claim 1.

  According to the present invention, it is possible to provide a white light source and an LED lighting device that are stable and easily excellent in color rendering, while securing a blue-green component in a light-emitting component. In addition, when only the yellow phosphor or the green phosphor is used, when the yellow phosphor or the green phosphor and the red phosphor are used in the range of the emission color temperature of 4500 to 6500 K, the emission color temperature of 3500 to 3500 is used. In the range of 6500K, a single kind of LED element is used, and an excellent color rendering property can be obtained as compared with a conventional white light source whose emission peak wavelength is excited by a single excitation light source.

It is a figure which shows an example of the emission spectrum from a blue LED element and a blue-green LED element. It is a side view of the white light source (LED module which attached the fluorescent member) used by the Example and the comparative example. It is a figure which shows the emission spectrum of the white light source of Example 10. FIG. It is a figure which shows the emission spectrum of the white light source of the comparative example 5. It is a figure which shows the emission spectrum of the white light source of the comparative example 12. It is the figure which plotted average color-rendering evaluation number Ra with respect to color temperature about the Example and comparative example using the light emitting member containing only yellow fluorescent substance. It is the figure which plotted average color-rendering evaluation number Ra with respect to color temperature about the Example and comparative example using the light emitting member containing a red fluorescent substance and a yellow fluorescent substance. It is the figure which plotted special color rendering index R12 with respect to color temperature about the Example and comparative example using the light emitting member containing a red fluorescent substance and a yellow fluorescent substance.

Hereinafter, the present invention will be described in more detail.
The white light source of the present invention includes an excitation light source including an LED element and a fluorescent member provided in front of the emission direction of the excitation light source. The white light source of the present invention is a so-called remote phosphor type light source, that is, a light source in which a fluorescent member is provided apart from the excitation light source via a vacuum layer or a gas layer with respect to the excitation light source. is there. The white light source of this invention is suitable as this white light source of an LED illuminating device provided with a white light source.

  A generally used white light source uses a blue LED element that emits blue light with a wavelength of 440 to 465 nm as an excitation light source, and includes a phosphor that emits yellow to green or red light when excited by blue light. Thus, a white LED package in which a blue LED element is sealed is formed, and a part of the blue light is converted into yellow to green or red light, and the converted light and the remainder of the blue light (unconverted blue light) The mixed light is extracted as white light. In such a white LED package, after forming an LED element that emits blue light by a semiconductor process, in a sealing material such as a transparent silicone resin or a transparent epoxy resin provided to cover the element for protection of the element The phosphors are mixed so as to obtain white light emission, light emission tests are performed on individual white LED packages, and the light emitting chromaticity is selected.

  The white light source of the present invention is formed by forming a fluorescent member made of a phosphor or a fluorescent member made of a transparent material or a translucent material containing the phosphor as a member different from the LED element or the LED package. This is a white light source provided in front of the light emitting direction of the element or LED package. In this case, the fluorescent member can be manufactured under the optimum conditions for toning without considering the sealing performance of the LED element separately from the LED package. Toning) is possible. In other words, since the emission color of the white light source can be precisely adjusted by blending the phosphors in the fluorescent member (that is, the toning of the emission color of the fluorescent member), each white LED package can be adjusted as in the past. Therefore, it is possible to efficiently provide a white light source excellent in color rendering without adjusting the emission color after strict color matching with respect to the LED lighting device.

  The white light source of the present invention includes two or more types of LED elements having different peak wavelengths, that is, a plurality of types of LED elements, as the LED elements included in the excitation light source. That is, the white light source of the present invention is a remote phosphor type white light source of multiple blue excitation light. Specifically, a blue LED element having a single emission peak with a wavelength of 440 nm or more and 465 nm or less, and a single emission peak with a wavelength of 10 nm or more longer than the single emission peak of the blue LED element and 480 nm or less. And a blue-green LED element. Therefore, the excitation light source of the present invention includes a plurality of LED elements. In the present invention, with respect to the fluorescent member, a plurality of types of LED elements having different wavelengths, that is, a blue LED element and a blue-green LED element are combined as an excitation light source, so that color rendering is performed in a wide range of emission color temperature. It is possible to provide a white light source with improved performance.

  In the white light source and LED lighting device of the present invention, the emission color temperature is 3500K or higher, preferably 4000K or higher, usually 6500 or lower, and a single type of LED element is used, and the emission peak wavelength is excited by a single excitation light source. Excellent color rendering can be obtained as compared with the white light source. For example, when only a yellow phosphor or a green phosphor is used, a yellow phosphor or a green phosphor and a red phosphor are used in combination within the emission color temperature range of 4500K or more, particularly 5500K or more and 6500K or less. Compared with a conventional white light source that uses a single type of LED element and emits light with a single excitation light source in the range of emission color temperature of 3500K or more, particularly 4000K or more, and 6500K or less, particularly 6000K or less. Excellent color rendering can be obtained.

  The blue LED element emits light having a single emission peak with a wavelength of 440 nm or more, preferably 445 nm or more and 465 nm or less, preferably 460 nm or less, similar to the blue LED elements used in conventional white light sources. Blue LED element to be used. The reason why the peak wavelength of the blue LED element is set to 440 nm or more is that light having a wavelength of less than 440 nm is outside the visible light region, and various effects due to near ultraviolet rays appear. On the other hand, when the peak wavelength exceeds 465 nm, when a white light source is used, a short blue component having a short wavelength in the obtained white light is insufficient, which is not preferable.

  As the blue-green LED element, the wavelength is 10 nm or more, preferably 15 nm or more, more preferably 20 nm or more, and 480 nm or less, preferably less than 480 nm, more preferably 475 nm or less than the peak wavelength of the blue LED element. A blue-green LED element that emits light having an emission peak is used. Therefore, the peak wavelength of the blue-green LED element is 450 nm or more, preferably 455 nm or more. The peak wavelength of the blue-green LED element is 40 nm or less, particularly less than 40 nm, particularly 35 nm or less than the peak wavelength of the blue LED element. In the present invention, by combining a blue LED element and a blue-green LED element, a blue-green color between the peak in the spectrum of the excitation light that causes a problem in the conventional white light source and the peak in the spectrum of the fluorescence from the fluorescent member. It becomes possible to obtain white light with good color rendering by complementing the light amount of the component.

  The peak wavelength of the blue-green LED element is set to 480 nm or less because the light exceeding the wavelength of 480 nm overlaps with the short wavelength side of the fluorescence spectrum from the fluorescent member, and thus the light in the blue-green wavelength region is not sufficiently complemented. It is because it becomes. The peak wavelength of the blue-green LED element is set to 10 nm or more from the peak wavelength of the blue LED element. When the peak wavelength is less than 10 nm, most of the light emission from the blue-green LED element overlaps with the light emission from the blue LED element. In this case as well, the light in the blue-green wavelength region is not sufficiently supplemented.

The ratio between the energy intensity (E _S ) of the peak wavelength in the emission spectrum of the blue LED element and the energy intensity (E _L ) of the peak wavelength in the emission spectrum of the blue-green LED element of the excitation light source depends on the target emission. _{Although S} > E _L , E _S = E _L , or E _S <E _L , the light from the blue LED element mainly functions as light for exciting the phosphor. The light from the blue-green LED element secondarily excites the phosphor, but mainly functions as light that is transmitted without being absorbed by the phosphor, that is, the former is the main excitation light and the latter is It is preferable to act on the phosphor as the secondary excitation light. The intensity ratio (E _S / E _L ) between the two is practically 0.4 or more in terms of brightness. This is because when the value of E _S / E _L is less than 0.4, the yellowish green light in the light emitting component increases, but the main excitation light component necessary for excitation of the phosphor is insufficient, and the illuminance decreases. It is because it ends. Further, the value of E _S / E _L is preferably 0.8 or more in order to obtain high color rendering properties, and more preferably 1 or more when particularly good color rendering properties are desired.

  As an excitation light source, an LED element (herein, an LED element refers to a semiconductor light emitting element itself as a light emission starting point, and a blue LED element and a blue green LED element use a PN junction diode formed of gallium nitride. In addition to wiring, current-carrying terminals, chip dies, etc., for the purpose of improving, for example, moisture resistance and oxidation resistance, transparent materials or translucent materials, for example, inorganic materials such as glass, resins, rubbers, elastomers, etc. An LED package sealed with an organic material such as an organic polymer material is preferably used. One LED element may be sealed in the LED package, or two or more LED elements may be sealed. As an excitation light source, one or two or more LED packages may be included.

  Specifically, if both a blue LED element and a blue-green LED element are sealed in one LED package, one or more such LED packages may be used, and only the blue LED element is sealed. When using an LED package and an LED package in which only blue-green LED elements are sealed, one or more of each LED package (that is, two or more LED packages) may be used. What is marketed can be used for an LED package as an independent component. The LED package is an LED package group in which only two LED packages of blue LED elements are combined, an LED package group in which only two LED packages of blue-green LED elements are combined, or an LED package of blue LED elements, You may use as an LED package group which combined the LED package of the blue-green LED element.

  In addition, if it is a range which does not impair the objective of this invention, LED elements other than the blue LED element mentioned above and a blue-green LED element or LED elements other than the blue LED element mentioned above and a blue-green LED element are included as an excitation light source. Although the LED package may be included, in this way, it becomes possible to adjust the emission color from the white light source with high accuracy, but the amount of fluorescence from the phosphor that determines the light quantity of the white light source is Since it does not increase so much and the light emission efficiency of the apparatus is lowered, it is preferable that the light emitting efficiency is configured to include only the blue LED element and the blue green LED element described above.

The fluorescent member included in the white light source of the present invention is a phosphor that emits light having a longer wavelength than the excitation light by being excited by excitation light from the LED element, particularly excitation light from the blue LED element that is the main excitation light. Is included. As this phosphor, a phosphor that emits fluorescence when excited by blue to blue-green light having a wavelength of 440 nm to 480 nm, particularly blue light having a wavelength of 440 nm to 465 nm is suitable. As such a phosphor, for example, a phosphor (yellow phosphor or green phosphor) that is excited by light having the above wavelength and emits a yellow or green wavelength is used. Specifically, a blue LED element is used. Y ₃ Al ₅ O ₁₂ : Ce (cerium activated yttrium aluminum garnet phosphor), (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ , (Y, Gd) ₃ Al, which are generally used for the white light source used ₅ O ₁₂ : Ce, Lu ₃ Al ₅ O ₁₂ : Ce (cerium activated lutetium aluminum garnet phosphor), (Lu, Y) ₃ Al ₅ O ₁₂ : Ce, Y ₃ (Al, Ga) ₅ O ₁₂ : Tb, (Sr, Ca, Ba) SiO ₄ : Eu, β-SiAlOn: Eu, and the like are mentioned. Among them, Y ₃ Al ₅ O ₁₂ : Ce, Lu ₃ Al ₅ O ₁₂ : Ce is suitable, and activation of Ce Rate (with respect to the total amount of Y and Ce Y ₃ Al ₅ O ₁₂ having a Ce ratio of 0.2 to 8 mol%: Lu ₃ Al ₅ O having an activation rate of Ce and Ce (a ratio of Ce to the total amount of Lu and Ce) of 0.1 to 7 mol% ₁₂ : Ce is particularly preferred. As the phosphor, only one or both of a yellow phosphor and a green phosphor may be used. When only one or both of the yellow phosphor and the green phosphor are used, white light having an average color rendering index Ra of 65 or more, particularly 70 to 80, can be obtained. When compared at the same color temperature, Ra can be increased by at least 3 points, and in some cases by 20 points or more, compared to the case where only a single type of blue LED is used. In addition, at a high color temperature of 5000 K or higher, the blue color reproducibility that is a problem with the white LED light source, that is, the color rendering index R12 can be improved by 10 points or more.

When light emission with a low color temperature of 5000K or less is required, excitation is performed by excitation light from an LED element, particularly excitation light from a blue LED element, which is main excitation light, together with a yellow phosphor or a green phosphor. It is particularly preferable that a phosphor other than the yellow phosphor and the green phosphor that emit light having a longer wavelength than the light is included. As such a phosphor, a phosphor (red phosphor) that emits light having a red wavelength when excited by blue to blue-green light having a wavelength of 440 nm to 480 nm, particularly blue light having a wavelength of 440 nm to 465 nm. It is preferable to use it. Specific examples of such phosphors include CaAlSiN: Eu ²⁺ , (Sr, Ca) AlSiN ₃ : Eu ³⁺ , manganese double fluoride phosphors, and the like. When a yellow phosphor or a green phosphor and a red phosphor are used in combination and a blue LED element and a blue-green LED element are applied as in the present invention, the average color rendering index Ra is 95 or more, particularly 96 or more, especially A white light source that emits 97 or more white light can be obtained.

As the red phosphor, it is preferable to use a manganese-activated bifluoride phosphor in that higher color rendering properties can be obtained. Specifically as a manganese activation double fluoride fluorescent substance, the following composition formula (1)
A ₂ (M _1-x , Mn _x ) F ₆ (1)
(In the formula, A is selected from Li, Na, K, Rb and Cs and contains at least one or two or more alkali metal elements containing Na and / or K, and M is Si, Ti, Zr, Hf, Ge And a phosphor represented by x is a positive number in the range of 0.001 to 0.3 (hereinafter the same)). This phosphor is a manganese-activated bifluoride phosphor having a structure in which some of the constituent elements of the double fluoride represented by A ₂ MF ₆ are substituted with manganese. Among these, a manganese-activated potassium silicofluoride phosphor represented by K ₂ (Si _1-x , Mn _x ) F ₆ is particularly preferable from the viewpoint of excitation wavelength range and weather resistance. In this manganese-activated bifluoride phosphor, the activation element manganese is not particularly limited, but is obtained by replacing the tetravalent element site represented by M with manganese, that is, tetravalent manganese (Mn ^{4 The} structure substituted as ⁺ ) is preferred. In that case, A ₂ MF ₆ : Mn ⁴⁺ (in the case of a manganese activated potassium silicofluoride phosphor, K ₂ SiF ₆ : Mn ⁴⁺ ) may be used.

The manganese-activated bifluoride phosphor is excited by blue light having a wavelength of 440 nm or more and 460 nm or less, and emits fluorescence having an emission peak or a maximum emission peak in a wavelength range of 600 to 660 nm. Unlike red phosphors such as CaAlSiN: Eu ²⁺ , (Sr, Ca) AlSiN ₃ : Eu ³⁺ , the light absorption characteristics of manganese-activated bifluoride phosphors have a sharp absorption rate when the wavelength is longer than 460 nm. Therefore, the light emitted from the blue-green LED element used as the excitation light source is hardly attenuated by the manganese-activated bifluoride phosphor. Therefore, the present invention using a blue-green LED element is advantageous.

  The fluorescent member can be composed only of a fluorescent material, but a particulate fluorescent material (for example, an average particle diameter D50 (volume basis) of 2 to 20 μm) is made of an inorganic or organic transparent material or translucent material, Specifically, a material dispersed in an inorganic material such as glass or an organic material such as an organic polymer material such as resin, rubber, or elastomer is preferable. It is preferable that the phosphor is uniformly dispersed in a transparent material or a translucent material that forms the base material of the fluorescent member.

  The concentration of the phosphor in the fluorescent member is the type of phosphor used, the particle size, the type of transparent or translucent material, the emission color temperature obtained when a white light source is used, the thickness, the arrangement of the LED element and the fluorescent member. Depending on other various conditions, the total amount of the phosphor is preferably 2% by mass or more, particularly 3% by mass or more, and 20% by mass or less, particularly preferably 15% by mass or less.

For example, when Y ₃ Al ₅ O ₁₂ : Ce phosphor is dispersed in a resin to form a fluorescent member having a thickness of 0.5 to 5 mm and white light having a color temperature of 6000 K is to be obtained, Y ₃ Al ₅ O ₁₂ : The concentration of the Ce phosphor is approximately 2 to 8% by mass. More specifically, when a fluorescent member having a thickness of 2 mm is used to obtain white light having a color temperature of 6000 K, the concentration of the Y ₃ Al ₅ O ₁₂ : Ce phosphor is approximately 3 to 6% by mass.

Further, Y ₃ Al ₅ O _12: with Ce phosphor, the case of using a manganese-activated double fluoride phosphors, the concentration of manganese activated double fluoride phosphor, Y ₃ Al ₅ O _12: Ce phosphor is generally 2 ~ 4 times. Specifically, for example, a Y ₃ Al ₅ O ₁₂ : Ce phosphor and a manganese-activated bifluoride phosphor are dispersed in a resin to form a fluorescent member having a thickness of 0.5 to 5 mm, and white having a color temperature of 3500K. When trying to obtain light, the concentration of the Y ₃ Al ₅ O ₁₂ : Ce phosphor is approximately 2 to 5% by mass, and the concentration of the manganese-activated bifluoride phosphor is approximately 6 to 13% by mass. More specifically, when a fluorescent member having a thickness of 2 mm is used and white light having a color temperature of 3500 K is to be obtained, the concentration of the Y ₃ Al ₅ O ₁₂ : Ce phosphor is approximately 2 to 5% by mass, The concentration of the fluoride phosphor is approximately 5 to 10% by mass.

  As the transparent material or translucent material, among organic polymer materials, it is preferable to use a resin, particularly a hard resin. Examples of the resin include thermosetting resins such as silicone resins and epoxy resins, or ultraviolet curable resins, olefin resins such as polyethylene and polypropylene, cyclic polyolefin resins, acrylic resins, polystyrene, AS resins, ABS resins, and other styrene resins. And thermoplastic resins such as ester resins such as acrylic imide resins, polycarbonate resins, and PET resins. In particular, when a manganese-activated bifluoride phosphor is used as the phosphor, among the thermoplastic resins exemplified above, a resin other than the ester resin is suitable. When a manganese-activated double fluoride phosphor and an ester resin are used, the resin may be dissolved or embrittled by a hydrolysis reaction. In contrast, in olefin resins such as polyethylene and polypropylene, cyclic polyolefin resins, acrylic resins, polystyrene, AS resins, styrene resins such as ABS resins, and acrylic imide resins, Thus, particularly effective kneading and high dispersibility can be obtained without causing the above problems.

  A soft resin such as an elastomer resin can be used when it is not necessary to maintain the shape as an independent member because the thickness and the volume density of the phosphor vary depending on conditions such as temperature and load. In addition, in the case of obtaining a fluorescent member having a thickness of several millimeters with a thermosetting resin or ultraviolet curable resin that is cured by heat or ultraviolet rays, it takes several tens of minutes to complete the curing, and mixed in the meantime. Aggregation and sedimentation may occur in the phosphor, and the dispersibility of the phosphor may not be obtained.

  From this point of view, as a transparent material or a semi-transparent material, when the fluorescent member is disposed in front of the light emission direction of the excitation light source, the shape can be maintained independently, the curing is fast, and the phosphor is easily mixed and molded. A thermoplastic resin capable of maintaining the dispersibility of the resin, particularly a hard thermoplastic resin is preferred. In the case of thermoplastic resins, those having a melt flow rate specified by JIS K 7210 of about 5 to 30 g / min have a good balance between the dispersibility of the phosphor and the moldability at the time of molding, particularly at the time of injection molding. Is particularly preferred. Furthermore, considering the heat generation of the phosphor excited by the excitation light source, the fluorescent member is preferably a resin having heat resistance to such an extent that it is not deformed by continuous use at 70 ° C. or higher. In particular, silicone resins, cyclic olefin resins, polycarbonate resins, and the like have high deformation temperatures, but when used for a long time under high temperature conditions, yellow or brown coloring may occur. There is a need.

  As in the case of general resin materials, the fluorescent member can use an antioxidant, a light stabilizer, a stabilizer such as an ultraviolet absorber, an auxiliary agent such as a metal deactivator and a molding lubricant. The light stabilizer and the ultraviolet absorber are preferably not used as much as possible because they absorb blue light from the excitation light source to a slight extent and may deteriorate the performance as a white light source. In addition, in a fluorescent member with a small thickness and a low phosphor concentration, the proportion of the excitation light from the excitation light source that is perpendicularly incident on the incident surface to the fluorescent member is large due to the layout of the excitation light source and the fluorescent member of the white light source. In such a case, “blue loss” may occur in which the amount of blue light that passes between the phosphor particles increases in the fluorescent member. In order to avoid such “blue omission”, fine powders such as talc, aluminum oxide, yttrium oxide, and silicon aluminum oxide are used to increase the haze in order to increase the diffusibility of light transmitted through the fluorescent member. As the light diffusing material, it can be dispersed in the fluorescent member together with the fluorescent material. The effect of the light diffusing material depends on the particle diameter, and generally, the average particle diameter D50 is preferably 0.1 μm or more and 20 μm or less. If the average particle diameter D50 is less than 0.1 μm or exceeds 20 μm, the effect of the light diffusing material may be greatly reduced. The density | concentration in the fluorescent member of a light-diffusion material is about 0.05-5 mass%, and a density | concentration can be made low, so that the average particle diameter D50 is small.

  The method for forming the fluorescent member is not particularly limited, and a thermoplastic resin is used when a conventionally known method such as compression molding, extrusion molding, injection molding or the like can be applied when an organic polymer material such as a resin is used as a base material. In this case, it is preferable to use injection molding in which variations in molding dimensions and molding density are small, and the phosphor can be formed and cured without giving time for aggregation or sedimentation of the phosphor during molding.

  As a normal molding process of a fluorescent member using a thermoplastic resin, for example, after mixing a thermoplastic resin, a phosphor, and an auxiliary agent if necessary with a kneader, the desired light emission of the fluorescent member is achieved. At the same time, thermoforming into a predetermined shape. In this case, for example, the fluorescent member of the white light source may be formed into a predetermined shape as it is at the time of kneading, but a method of once forming pellets after kneading is also suitable. In this case, after preparing one kind of pellets, or preparing two or more kinds of pellets having different components and concentrations, and mixing them appropriately, the desired shape of the fluorescent member is adjusted to a predetermined shape. By thermoforming, a fluorescent member having good light emission characteristics can be produced efficiently and accurately. Examples of the shape of the fluorescent member include a sheet shape, a plate shape, a cup shape, and other bulk shapes.

The thickness of the fluorescent member is approximately C = N ^(−0.6) with respect to the concentration C of the phosphor concentration when the transmission thickness of the excitation light is N times. As the fluorescent member becomes thinner, The concentration of the phosphor to be dispersed increases rapidly. That is, the influence of the thickness of the fluorescent member on the phosphor concentration increases rapidly as the fluorescent member becomes thinner. The white light source of the present invention employs a remote phosphor system that can adjust the chromaticity with high reproducibility by providing a fluorescent member as a separate member that is spatially independent from the excitation light source. If the thickness of the fluorescent member is excessively reduced, the tolerance of the thickness of the fluorescent member and the phosphor concentration may be reduced more than necessary. On the other hand, when the thickness of the fluorescent member is increased, the total amount of phosphors to be used increases per thickness of the fluorescent member. Therefore, the thickness of the fluorescent member is preferably 0.5 mm or more, particularly 1 mm or more, 5 mm or less, particularly 3 mm or less.

In the white light source of the present invention, high-color rendering white light is emitted by using two types of LED elements, a blue LED element and a blue-green LED element, as the excitation light source. An example of the emission spectrum of a blue LED element and a blue-green LED element is shown in FIG. In this case, the excitation light has a peak derived from light from the blue LED element on the low wavelength side and a peak derived from light from the blue-green LED element on the long wavelength side, and the excitation light The peak intensity is set higher than the peak intensity of light from the blue-green LED element. Using a blue LED element and a blue-green LED element having such a spectrum as an excitation light source, Y ₃ Al ₅ O ₁₂ : Ce phosphor as a yellow phosphor or green phosphor, and K ₂ SiF ₆ : Mn fluorescence as a red phosphor. When a white light source is constituted by a fluorescent member containing a body and the spectrum of the emitted light is confirmed, a spectrum as shown in FIG. 3 is obtained. In the obtained spectrum, the peak of the low wavelength side and the long wavelength side are configured at a ratio different from the peak intensity of the light from the blue LED element of the excitation light source and the peak intensity of the light from the blue-green LED element, Each peak wavelength is shifted by several nm. This shift of the peak wavelength is considered to be a result of the mutual influence of the overlapping of the emission wavelengths of the blue LED element and the blue-green LED element, the overlapping of the fluorescence from the phosphor, and the absorption characteristics of the phosphor.

Therefore, paying attention to the influence on the color rendering properties of the white light obtained, in particular, the blue-green LED elements that particularly affect the color rendering properties and the peak in the blue-green region in the emission spectrum of the white light source, the blue LED elements and the blue-green colors The light emission characteristics of the LED element, and further, the peak in the blue to blue-green region and the intensity thereof in the emission spectrum of the obtained white light source, and the intensity of the blue to green component during light emission increase. When trying to obtain white light having a temperature of 3500K or higher, particularly 4000K or higher, the spectrum has a plurality of peaks in the wavelength range of 400 nm to 500 nm, and the shortest wavelength among the plurality of peaks. and energy intensity of the peak of the side (E _S), the ratio (E _S / E _L) between the maximum peak of the energy intensity of the peak of the residual (E _L) is 0.8 or more, particularly In case where more effective white light spectrum as high color rendering property of the white light source is found to result.

Specifically, when a blue LED element and a blue-green LED element are used, the energy intensity of a peak near the wavelength of 450 nm (peak on the shortest wavelength side) that is considered to be derived from an unconverted component of excitation light from the blue LED element. (E _S ) and the energy intensity (E _L ) of the peak (the maximum peak of the remaining peaks) that is considered to be derived from the unconverted component of the excitation light from the blue-green LED element on the longer wavelength side When the ratio (E _S / E _L ) is 0.8 or more, particularly 1 or more, high color rendering properties can be obtained. When the ratio E _S / E _L is less than 0.8, the color rendering in the deep blue region caused by the excitation light from the blue LED element is lowered, and the reproduction range of the blue hue is narrowed. In addition, the upper limit of the ratio E _S / E _L is not particularly limited, but the relatively small E _L is that the peak is lost and the blue-green component is reduced. As a result, the effect of improving the color rendering properties is lowered, so that it is preferably 5 or less, particularly 2 or less.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[Examples 1 to 16, Comparative Examples 1 to 12]
First, methacrylic resin (Asahi Kasei Co., Ltd., Delpet 60N) pellets were dried at 90 ° C. for 6 hours. Next, Y ₃ Al ₅ O ₁₂ : Ce phosphor (Ce activation rate 2 mol%) was used as the yellow phosphor, and K ₂ SiF ₆ : Mn phosphor (Mn activation rate 3 mol%) was used as the red phosphor. In a content of 25% by mass, separately kneaded into a methacrylic resin, a red phosphor-containing resin pellet and a yellow phosphor-containing resin pellet are mixed into a twin-screw kneading extruder (Toshiba Machine Co., Ltd., TEM-18SS, The same applies hereinafter).

In addition, using a yellow phosphor-containing resin pellet and a phosphor-free methacryl resin pellet, the concentration of Y ₃ Al ₅ O ₁₂ : Ce phosphor is 21 types in the range of 6 to 10% by mass in increments of 0.2% by mass. A total of 21 types of resin pellets containing only a yellow phosphor were produced using a biaxial kneading extruder.

Next, a red phosphor-containing resin pellet, a yellow phosphor-containing resin pellet, and a phosphor-free methacrylic resin pellet are used, and the K ₂ SiF ₆ : Mn phosphor concentration is 2 to 4% by mass in increments of 0.2% by mass. 11 types of Y ₃ Al ₅ O ₁₂ : Ce phosphor concentrations in the range of 5.5 to 8% by mass in increments of 0.25% by mass, and 121 types of red with different concentrations. Resin pellets containing both the phosphor and the yellow phosphor were produced with a biaxial kneading extruder.

  Next, each of 142 types of resin pellets containing only yellow phosphors and 142 resin pellets containing both red phosphors and yellow phosphors is molded with an injection molding machine (FANUC CORPORATION, α-S30iS). Thus, a total of 142 kinds of fluorescent members having a disc shape of 60 mmφ and 2 mmt having different phosphor compositions were obtained.

  As an excitation light source, an LMH-2 type LED module (manufactured by Cree) is used as a housing, and four XT-E blue LED packages (manufactured by Cree) having a peak wavelength of 447 nm and XT- having a peak wavelength of 467 nm are contained therein. A two-wavelength LED module incorporating four E-type blue-green LED packages (manufactured by Cree), a total of eight, was prepared. Here, four blue LED packages with a peak wavelength of 447 nm are configured in series connection, and four blue-green LED packages with a peak wavelength of 467 nm are configured in another series connection circuit, and the emission ratio of each wavelength is adjusted by adjusting the current. It was possible. Further, as a comparative excitation light source, a single wavelength LED module comprising only six XT-E type blue LED packages (manufactured by Cree) having a peak wavelength of 452 nm in a series connection circuit instead of the above eight LED packages. Prepared.

  Next, the 142 types of fluorescent members thus obtained were sequentially arranged at a position approximately 2 cm away from the LED package in front of the light emitting direction of the LED package of the two-wavelength LED module to obtain a white light source. An LED module (white light source) equipped with a fluorescent member is shown in FIG. In FIG. 2, 1 is a fluorescent member, 2 is an LED module body, 3 is a heat sink, and 4 is a spacer (Duracon (registered trademark) spacer).

Using the obtained white light source, the spectral irradiance meter (CL-500A, manufactured by Konica Minolta Japan Co., Ltd., hereinafter the same) is used to calculate the deviation (Δuv) from the black body locus of the emission color of the white light source from the light emitting member surface. Adjusting the current applied to the blue LED package with a peak wavelength of 447 nm and the blue-green LED package with a peak wavelength of 467 nm so that Δuv becomes the smallest while measuring, the color temperature when Δuv becomes the smallest, the peak wavelength in the range of wavelength of 400nm or more 500nm emission spectra were measured, of the peak wavelength, the most with the peak of the energy intensity of the short wavelength side (E _S), the maximum of the remaining peak (long wavelength side) and calculating the ratio (E _S / E _L) of the energy intensity of the peak (E _L).

  In addition, the 142 types of fluorescent members obtained were sequentially placed in front of the light emitting direction of the LED package of the single-wavelength LED module at a position approximately 2 cm away from the LED package to form a white light source, and with a spectral irradiance meter, The current applied to the blue LED package having a peak wavelength of 452 nm is adjusted so that Δuv becomes the smallest while measuring the deviation (Δuv) from the black body locus of the emission color of the white light source from the light emitting member surface. The color temperature and the peak wavelength in the range of the wavelength of the emission spectrum from 400 nm to 500 nm when it became the smallest were measured.

  Next, for each LED module, the obtained color temperature results were layered at a color temperature of approximately 500K, and Δuv was within the range of ± 0.03 in each color temperature range (Δuv If there are a plurality of the same, all of them were extracted. As a result, seven types (Examples 1 to 7) using a light emitting member containing only a yellow phosphor and a two-wavelength LED module, a light emitting member containing only a yellow phosphor, a single wavelength LED module, 4 types (Comparative Examples 1 to 4) using 9 and 9 types (Examples 8 to 16) using a light emitting member containing both a red phosphor and a yellow phosphor and a two-wavelength LED module Six types (Comparative Examples 5 to 12) were extracted using a light emitting member containing both a red phosphor and a yellow phosphor and a single wavelength LED module.

About the white light source of these Examples 1-16 and Comparative Examples 1-12, the color rendering index (Ra, R1-R15) and the emission spectrum were measured. Tables 1 to 4 show the color temperature, peak wavelength, E _S / E _L , and color rendering index of light emission from the light emitting member surfaces of the white light sources of Examples 1 to 16 and Comparative Examples 1 to 12, and Example 10 and comparison. The emission spectra of Example 5 and Comparative Example 12 are shown in FIGS.

  A light-emitting member containing only a yellow phosphor and a two-wavelength LED module (Examples 1 to 7), a light-emitting member containing only a yellow phosphor, and a single-wavelength LED module ( About Comparative Examples 1-4), the result of having plotted average color rendering index Ra with respect to color temperature is shown in FIG. In this case, the average color rendering index Ra is in the range of the color temperature of 5500 to 6500K, and the embodiment is improved by about 2 points, and the color rendering is improved.

Light emitting member containing both red phosphor and yellow phosphor, and one using two-wavelength LED modules (Examples 8 to 16 and Comparative Examples 11 and 12), containing both red phosphor and yellow phosphor FIG. 7 shows the result of plotting the average color rendering index Ra against the color temperature for the light emitting member to be used and the single wavelength LED module (Comparative Examples 5 to 10). In this case, the average color rendering index Ra is about 4 to 5 points higher in the color temperature range of 4000 to 6000K, and the color rendering properties are improved. Even at the lowest, Ra = 95.2, The highest color rendering property Ra = 97.6 is obtained. On the other hand, of the peak wavelengths, the ratio (E _S / E) between the energy intensity (E _S ) of the shortest peak and the maximum peak energy intensity (E _L ) of the remaining peaks (long wavelength side). _In Comparative Examples 11 and 12 in which _L ) was less than 0.8, the average color rendering index Ra was low, with Ra = 78.8 and 76.0, respectively.

Further, a light-emitting member containing both a red phosphor and a yellow phosphor and a two-wavelength LED module (Examples 8 to 16 and Comparative Examples 11 and 12), both a red phosphor and a yellow phosphor FIG. 8 shows the result of plotting the special color rendering index R12, which is a blue index, with respect to the color temperature of the light-emitting member containing the light-emitting member and the single-wavelength LED module (Comparative Examples 5 to 10). Show. In this case, the special color rendering index R12 is in the range of the color temperature of 3500 to 6500K, the embodiment is improved by about 20 points, the color rendering is greatly improved, and the effect of improving the color rendering in the blue region is particularly It was big. On the other hand, of the peak wavelengths, the ratio (E _S / E) between the energy intensity (E _S ) of the shortest peak and the maximum peak energy intensity (E _L ) of the remaining peaks (long wavelength side). _In Comparative Examples 11 and 12 in which _L ) was less than 0.8, the special color rendering index R12 had low color rendering properties of Ra = 34.2 and 41.4, respectively.

1 Fluorescent member 2 LED module body 3 Heat sink 4 Spacer

Claims (7)

A remote phosphor type white light source comprising: an excitation light source including a plurality of LED elements; and a fluorescent member provided in front of a light emission direction of the excitation light source and spaced apart from the excitation light source via a vacuum layer or a gas layer Because
The plurality of LED elements of the excitation light source have a blue LED element having a single emission peak with a wavelength of 440 nm or more and 465 nm or less, and the wavelength is 10 nm or more longer than the single emission peak of the blue LED element and 480 nm or less. A blue-green LED element having a single emission peak, and the fluorescent member includes a phosphor that is excited by excitation light from the LED element and emits light having a longer wavelength than the excitation light, and emitting color A white light source having a temperature of 3500K or higher. It has a plurality of peaks in the wavelength range of 400 nm to 500 nm of the emission spectrum, and among the plurality of peaks, the energy intensity (E _S ) of the shortest wavelength side peak and the maximum peak among the remaining peaks 2. The white light source according to claim 1, wherein a ratio (E _S / E _L ) to the energy intensity (E _L ) is 0.8 or more.   The white light source according to claim 1 or 2, wherein the excitation light source includes one or more LED packages in which one or more of the LED elements are sealed with a transparent material or a translucent material.   The white light source according to any one of claims 1 to 3, wherein the fluorescent member is obtained by dispersing the phosphor on the particles in an inorganic or organic transparent material or translucent material.   The phosphor is excited by blue to blue-green light having a wavelength of 440 nm to 465 nm, or emits light having a yellow or green wavelength, or the phosphor and blue to blue-green light having a wavelength of 440 nm to 465 nm 5. The white light source according to claim 1, wherein the white light source includes a phosphor that emits light having a red wavelength when excited by.   The phosphor that emits light of the yellow or green wavelength includes a cerium activated yttrium aluminum garnet phosphor and / or a cerium activated lutetium aluminum garnet phosphor, and the phosphor that emits light of the red wavelength is manganese activated. The white light source according to claim 5, comprising potassium silicofluoride.   An LED lighting device comprising the white light source according to claim 1.

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