JP5974394B2 - White light emitting device and lighting apparatus using the same - Google Patents

Description

  The present invention relates to a light-emitting device that emits light by exciting a phosphor with light from a solid-state light-emitting element such as an LED.

  Conventionally, as a lighting fixture that illuminates an irradiation body such as meat that is installed in a supermarket and arranged on a display shelf, a light source such as a fluorescent lamp is covered with an optical filter that cuts light of a predetermined wavelength. The one that emits light suitable for making the image look clear is used. In recent years, in place of fluorescent lamps and the like, lighting fixtures using LEDs that can emit light with high power and high brightness as a light source have become widespread. For example, products that use optical filters for LEDs that emit white light Lighting fixtures that can irradiate with light suitable for making the image look clear are used.

  As an LED that emits white light, an LED that emits near-ultraviolet light, violet light, or blue light is combined with a plurality of phosphors that convert the wavelength of light from the LED, and wavelength conversion is performed by the plurality of phosphors. A so-called white LED is known in which white light is generated by mixing the emitted light. Also, a white light emitting device is known in which this type of LED is provided with a filter that reduces the transmission of light of a predetermined wavelength (see, for example, Patent Document 1).

  By the way, as a spectrum of the light which irradiates meat, the thing with which the intensity | strength of a yellow light component is comparatively low and green and a red light component are emphasized is preferable. By using light having such a spectrum, the meat can be clearly produced without the appearance of dull meat. That is, if a light emitting device in which an LED is coated with an optical filter capable of cutting the wavelength of the yellow light component, an irradiated body such as meat can be clearly produced.

JP 2008-311532 A

  However, as shown in FIG. 6A, the spectrum of an LED that emits daylight white light generally has a yellow light component having a maximum peak intensity, and has many light components in this wavelength region. Therefore, when an optical filter that restricts the transmission of light in this wavelength region is used, most of the light emitted from the LED is cut, and there is a possibility that a sufficient luminous flux cannot be obtained. Further, when the above-described optical filter is used for the LED that emits light bulb-colored light, as shown in FIG. 6B, the balance between the green light component and the red light component in the transmitted light is deteriorated and There is a risk that the light becomes uncomfortable. Therefore, it is also possible to cut a part of the red light component so that the light does not feel uncomfortable with respect to the surroundings, but in that case, a sufficient luminous flux may not be obtained.

  An object of the present invention is to solve the above problems, and to provide a white light emitting device capable of reducing a yellow light component contained in irradiation light and obtaining a sufficient luminous flux, and a lighting fixture using the same. And

In order to achieve the above object, a light-emitting device of the present invention is provided with a solid-state light-emitting element that emits light included in a wavelength region of 10 to 550 nm and a light-emitting surface side of the solid-state light-emitting element, and transmits light with a specific wavelength And a wavelength conversion member provided between the solid-state light-emitting element and the optical filter, the solid-state light-emitting element having light having a peak wavelength in a wavelength region of at least 430 to 470 nm. And the wavelength conversion member is excited by light from the solid state light emitting device and converts the light into a light having a peak wavelength in a wavelength range of 630 to 680 nm, and a wavelength range of 500 to 550 nm. A second phosphor that converts the light into a peak wavelength, and the light intensities emitted from the first phosphor and the second phosphor are comparable to each other. It is configured, and the light intensity of the peak wavelength in the wavelength range of the 630-680 nm, and the light intensity of the peak wavelength in the wavelength range of the 500~550nm is, the light of a peak wavelength in the wavelength range of the 430~470nm It is higher than the intensity , and the optical filter selectively reduces transmission of light in a wavelength region of 580 to 600 nm, and the transmittance of the optical filter is 50% or less.

  The white light emitting device is preferably used for a lighting fixture.

  According to the white light emitting device of the present invention, the first and second phosphors that convert light from the solid light emitting element into light having peak wavelengths in the wavelength regions of 630 to 680 nm and 500 to 550 nm are used. . Therefore, the yellow light component contained in the light emitted from the wavelength conversion member can be reduced, and even if an optical filter that reduces the transmission of light in the wavelength region of 560 to 620 nm including this wavelength region is used, Reduction can be suppressed.

1 is a side sectional view of a white light emitting device according to an embodiment of the present invention. (A) (b) Side sectional drawing which shows the example of the light source part used for the white light-emitting device. The figure which shows each spectrum of the light from the 1st and 2nd fluorescent substance used for the wavelength conversion member of the light source part. The figure which shows the spectral spectrum of the emitted light of the same white light-emitting device. Spectral reflection characteristic diagram of meat. (A) is a figure which shows the spectrum in the case of using the optical filter which cuts a yellow light component for LED which radiate | emits daylight white light, (b) is the optical filter which cuts a yellow light component to LED which radiate | emits a bulb color light The spectrum which shows the spectrum in the case of using.

  A white light emitting device according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the white light emitting device 1 of the present embodiment is provided along a plurality of light source parts 2, a wiring board 3 on which these light source parts 2 are mounted, and a peripheral part of the wiring board 3. And a reflection frame 4 that distributes light from the light source unit 2 in a predetermined direction. In addition, the white light emitting device 1 includes an optical filter 5 that is provided in the light emission direction of the light source unit 2 and reduces transmission of light having a specific wavelength out of light from the light source unit 2. The optical filter 5 is fixed to the opening edge of the reflection frame 4 so as to be held at a constant interval from the light source unit 2.

  As shown in FIGS. 2A and 2B, the light source unit 2 is provided in a light emitting direction of the solid-state light emitting element (hereinafter referred to as LED) 21, a mounting substrate 22 on which the LED 21 is mounted, and the LED 21. And a wavelength conversion member 6 that converts the wavelength of the light. For example, as illustrated in FIG. 2A, the light source unit 2 includes a frame body formed so that the mounting substrate 22 surrounds the LEDs 21, and the wavelength conversion member 6 is disposed at the opening edge of the frame body. Further, the frame body may be appropriately filled with a sealing material or the like, and the filler may contain a different type of phosphor from the wavelength conversion member 6, and further a light diffusing material, an ultraviolet absorber or the like is added. May be. In addition, as shown in FIG. 2B, the light source unit 2 may have a rectangular plate member as the mounting substrate 22. In this case, the wavelength conversion member 6 is provided so as to cover the light emitting surface of the LED 21. It is done. Further, for example, as shown in FIG. 2A, the light source unit 2 includes a frame body formed so that the mounting substrate 22 surrounds the LEDs 21, and the wavelength conversion member 6 has an opening edge of the frame body. The LED 21 may be disposed so as to cover the light emission surface.

  For the LED 21, a solid light emitting element (LED chip) that emits light including a wavelength in any band of 10 to 500 nm is used. Specifically, LED chips that emit ultraviolet light (peak wavelength 10 to 350 nm), violet light (peak wavelength 350 to 430 nm), blue light (peak wavelength 430 to 470 nm), and green light (peak wavelength 470 to 550 nm) Can be mentioned. In the present embodiment, an LED chip that emits blue light of 430 to 470 nm is used. This wavelength range is advantageous in that natural white light is easily generated by combination with a phosphor to be described later, and since it does not include ultraviolet light, it is difficult to damage the phosphor and other resin materials.

  The LED 21 may be sealed with a transparent material (not shown) such as silicone resin, epoxy resin, or glass, or may be covered with a transparent lens body. The shape of the state in which the LED 21 is covered with the transparent member is not particularly limited, and for example, a condensing lens function may be provided as a bullet shape or a semi-spherical shape. Further, a diffusion material (particles made of an inorganic material such as aluminum oxide or silica, or an organic material such as a fluorine resin), a pigment, or the like may be appropriately dispersed in the binder. In addition, a molded body may be formed with a binder in which a phosphor described later is dispersed, and the LED 21 may be covered with the molded body. Further, the LED 21 may be an OLED using an organic material for the light emitting portion.

  The mounting substrate 22 is a general-purpose substrate formed of glass epoxy or the like, and its planar outer shape is a shape corresponding to the shape of the LED 21, for example, a rectangular shape, and various conductive patterns (such as a rectangular shape) electrically connected to the LED 21. (Not shown) is formed. Further, a through hole (not shown) is formed in the mounting substrate 22, and the lead wire taken out from the anode / cathode electrode of the LED 21 is inserted through the through hole to form a wiring pattern formed on the wiring substrate 3. Electrically connected.

  The wavelength conversion member 6 is excited by light of 500 nm or less emitted from the LED 21 and converted into light having a peak wavelength in the wavelength region of 630 to 680 nm, and in the wavelength region of 500 to 550 nm. A second phosphor 62 that converts the light into light having a peak wavelength. The first phosphor 61 and the second phosphor 62 are dispersed and held in a binder 60 made of a transparent material such as a silicone resin or an epoxy resin. In addition, a diffusion material (a diffusion material such as particles made of an inorganic material such as aluminum oxide or silica, or an organic material such as a fluorine resin), a pigment, or the like may be appropriately dispersed in the binder 60.

  FIG. 3 shows an example of spectral spectra of the first phosphor 61 and the second phosphor 62. In this example, the spectrum of the first phosphor 61 has a maximum value near 650 nm, and the spectrum of the second phosphor 62 has a maximum value near 530 nm. Moreover, what radiates | emits the light with a small half value width of the peak wavelength in each spectrum is suitably used for the 1st fluorescent substance 61 and the 2nd fluorescent substance 62. FIG. If it carries out like this, in the emitted light from the light source part 2, it can be set as natural white light, maintaining the presentation property of to-be-irradiated object (especially meat).

  The wavelength conversion member 6 is configured such that the light intensities emitted from the first phosphor 61 and the second phosphor 62 are approximately the same. By so doing, the emitted light from the white light emitting device 1 includes the emitted light from each phosphor in a well-balanced manner, so that more natural white light can be obtained. The first phosphor 61 and the second phosphor 62 preferably have the same light intensity. If the light intensity of the first phosphor 61 itself is higher than the light intensity of the second phosphor 62 itself, the concentration of the first phosphor 61 dispersed in the binder is changed to the second phosphor 62. It should be lower. Even when the light intensity of the second phosphor 62 itself is high, the concentration of the second phosphor 62 may be lowered as described above.

The wiring substrate 3 is a substrate having electrical insulation properties and high thermal conductivity. For example, metal oxides (including ceramics) such as aluminum oxide (Al ₂ O ₃ ) and aluminum nitride (AlN), metal It is made of a material such as nitride, metal, or resin. A wiring pattern made of a conductive metal such as gold (Au) or silver (Ag) is provided on one surface of the wiring board 3, and this wiring pattern is electrically connected to the light source unit 2. An element terminal portion (not shown) is formed on one end side of the wiring pattern via a bump (not shown) made of a metal material such as Au or solder, and an external connection terminal portion is formed on the other end side. Is done. The wiring pattern is covered with an insulating layer except for the element terminal portion and the external connection terminal portion.

  The reflection frame 4 is a structural member having a conical cylinder shape whose surface facing the light source unit 2 has reflectivity. As this, for example, a plastic material such as ABS resin, acrylic resin, polystyrene resin or the like is formed into a predetermined shape and the surface thereof is coated with a metal reflective film or reflective paint, or a metal material such as aluminum is used. Those formed are used.

  The optical filter 5 reduces the transmission of light in the wavelength region of 560 to 620 nm, and for example, a light absorption filter or a light reflection filter is used. As a light absorption filter, a transparent material such as glass or plastic, a material containing a specific dye, pigment, pigment or other additive alone or in combination of a plurality of types, or a material that absorbs only light of a specific wavelength. A material obtained by processing a metal ion-doped material into a flat plate shape can be used. Examples of the light reflection filter include a plate-like glass or plastic surface formed with a coating film, and this coating film may be formed of a single material, or a plurality of layers may be formed of a plurality of materials. Also good.

  In the present embodiment, as the optical filter 5, an optical multilayer film in which a high refractive index material such as titanium oxide and a low refractive material such as silicon oxide are laminated is suitably used. This optical multilayer film has a high refractive index material and a low refractive material with a predetermined film thickness and a predetermined number of layers, thereby allowing light of a specific wavelength to interfere and transmitting light of that wavelength. It can be selectively reduced.

  Next, the operation of the white light emitting device 1 configured as described above will be described. When a voltage is applied between the anode and cathode electrodes of the LED 21, the LED 21 emits blue light of 430 to 470 nm. The first phosphor 61 and the second phosphor 62 contained in the wavelength conversion member 6 are excited by light from the LED 21 and emit light having peak wavelengths in the wavelength regions of 630 to 680 nm and 500 to 550 nm, respectively. Radiate. These 430 to 470 nm, 630 to 680 nm, and 500 to 550 nm color lights are mixed into the wavelength conversion member 6 and emitted as white light from the surface of the wavelength conversion member 6. The white light is emitted from the surface of the optical filter 5 with the optical filter 5 restricting transmission of light in the wavelength region of 580 to 600 nm.

  FIG. 4 shows a spectral spectrum of the irradiation light of the white light emitting device 1 configured as described above. The peak wavelength in the wavelength region of 430 to 470 nm seen in this spectrum is due to the emitted light of the LED 21. The peak wavelength in the 630 to 680 nm wavelength region is attributed to the first phosphor 61, and the peak wavelength in the 500 to 550 nm wavelength region is attributed to the second phosphor 62. The first phosphor 61 and the second phosphor 62 preferably have a small half-value width of emitted light, and particularly preferably have a small light intensity in the wavelength range of 550 to 630 nm. By so doing, the light intensity of the yellow light component is reduced, while the light intensity of the red light component and the green component is increased, so that the redness of the food that is the object to be irradiated can be emphasized. In this example, the optical filter 5 is configured to reduce the transmission of light in the wavelength region of 580 to 600 nm.

  FIG. 5 shows an example of the spectral reflection characteristics of meat. As shown in this spectral reflection characteristic, the peak of the spectral reflectance of meat is in a wavelength region longer than 600 nm, and in a wavelength region shorter than 600 nm (for example, a yellow light region), the spectral reflectance suddenly decreases. become.

  That is, according to the irradiation light of the spectral spectrum shown in FIG. 4, by taking out the red light component centering around 630 to 680 nm, which is a wavelength region where the spectral reflectance of food (especially meat) is high, The redness of a food can be emphasized. Moreover, by reducing the yellow light component centered at 580 to 600 nm, the food that is the object to be irradiated can be seen without being dull, and the effect of producing the food can be further improved. Furthermore, natural white light can be realized by taking out a green light component centered at 500 to 550 nm.

  As described above, the optical filter 5 only needs to reduce the transmission of light in the wavelength region of 560 to 620 nm. However, when the wavelength region for reducing the transmission of light is wide, most of the light from the light source unit 2 is cut, and there is a possibility that the light flux is significantly reduced. Therefore, in this case, the transmittance of the optical filter 5 is preferably about 50%. In this way, it is possible to obtain an effect of suppressing a significant decrease in the luminous flux and reducing the yellow light component of the irradiation light so that the food that is the object to be irradiated is not dulled.

In contrast, as 580~600nm in FIG 4, when the wavelength region for reducing the transmission of light is small, the transmittance of the optical filter 5 is preferably a lower 50% or less. The wavelength range of 580 to 600 nm contains a yellow light component that causes dullness. Therefore, by selectively restricting the transmission of light in this wavelength region, the yellow light component in the irradiation light can be intensively suppressed, and the effect of producing food can be further improved. Further, according to the irradiation light of this spectral spectrum, a narrow wavelength region is selectively limited, so that the irradiated object can be illuminated with high illuminance without significantly reducing the luminous flux.

Example 1
The LED 21 that emits blue light having a peak wavelength of 450 nm was mounted on the mounting substrate 22. A wavelength obtained by dispersing a first phosphor 61 that emits red light having a peak wavelength of 650 nm and a second phosphor 62 that emits green light having a peak wavelength of 530 nm in a silicone resin. The conversion member 6 was coated on the surface of the LED 21. Furthermore, an optical filter 5 having a transmittance of 50% at a wavelength of 580 to 600 nm was installed on the exit surface side, and the white light emitting device 1 of Example 1 was produced.

(Comparative Example 1)
The light-emitting device of Comparative Example 1 is mounted by mounting a light bulb color LED having a color temperature of 2700 K on a predetermined wiring board, and installing an optical filter 5 having a transmittance of 50% at a wavelength of 580 to 600 nm on the emission surface side. Produced. In addition, the spectral spectrum irradiated by the light-emitting device of the comparative example 1 is referred to the example of FIG.

(Evaluation of irradiation light)
First, the light flux in the irradiation light of the white light emitting devices of Example 1 and Comparative Example 1 manufactured as described above was measured using a general-purpose total light flux measuring device. Moreover, when food was irradiated with light from each light-emitting device, the evaluation was made with a metric chroma value (C ^* _ab ) suitable for chroma evaluation as an evaluation index as to whether or not the food was visible. In the evaluation of the metric chroma value, when the illuminating body is illuminated, the larger the value, the higher the saturation, and the illuminating body can be rendered more preferably. This metric chroma values, from the spectral reflectance of the meat the spectral distribution and the irradiated object of the irradiation light, CIEL ^* a ^* b ^* color space (CIE1976L ^* a ^* b ^* uniform color space, represented by a color system) Is calculated from the values of a ^* and b ^* by the following equation. In the following formula, a ^* and b ^* are perceptual chromaticity indexes in the CIEL ^* a ^* b ^* color space.

[Equation 1]
C ^* _ab = (a ^* 20 + b ^{* 2} ) ^1/2

  The luminous flux and metric chroma values measured as described above are shown in Table 1 below. The luminous flux is shown as a ratio when the comparative example is 100.

  In Example 1 and Comparative Example 1, the same optical filter 5 was used, and each yellow light component was suitably limited, so that it was shown that a large metric chroma value can be obtained in both cases. On the other hand, the luminous flux in Example 1 was 1.3 times that of Comparative Example 1. That is, the first phosphor 61 that emits red light having a peak wavelength of 650 nm and the second phosphor 62 that emits green light having a peak wavelength of 530 nm are selectively used for the wavelength conversion member 6. ing. Therefore, the white light from the light source part 2 of Example 1 can make the light intensity of a yellow light component small compared with the light bulb color light of Comparative Example 1. Therefore, in Example 1, since the amount of reduction of the yellow light component by the optical filter 5 is smaller than that in Comparative Example 1, a high metric chroma value can be obtained without reducing the luminous flux.

  In addition, this invention is not restricted to the structure of said embodiment, A various deformation | transformation is possible in the range which does not change the summary of invention. For example, the wavelength conversion member 6 may be provided between the LED 21 and the optical filter 5 and may not be configured as the light source unit 2 described above. In addition to the wavelength conversion member 6, a transparent member including a light dispersion material or the like may be provided between the LED 21 and the optical filter 5. Moreover, the wavelength conversion member 6 may be produced by containing the first phosphor 61 and the second phosphor 62 in separate binders and laminating them. Further, the white light emitting device 1 includes the light source unit 2 including the wavelength conversion member 6 including only the first phosphor 61 and the light source unit 2 including the wavelength conversion member 6 including only the second phosphor 62. A plurality of them may be arranged on the wiring board 3 to mix the light of these light source units 2. Note that the lighting fixture using the white light emitting device 1 is not limited to irradiating food (especially meat) with irradiation light, but can also be applied to various display products such as clothing other than food.

1 Light Emitting Device 21 LED (Solid State Light Emitting Element)
5 Optical Filter 6 Wavelength Conversion Member 61 First Phosphor 62 Second Phosphor

Claims (2)

A solid-state light-emitting element that emits light included in a wavelength region of 10 to 550 nm, an optical filter that is provided on a light-emitting surface side of the solid-state light-emitting element and reduces transmission of light of a specific wavelength, the solid-state light-emitting element, and the optical A wavelength conversion member provided between the filter and
The solid state light emitting element emits light having a peak wavelength in a wavelength region of at least 430 to 470 nm;
The wavelength conversion member is excited by light from the solid state light emitting device, and converts the first phosphor to light having a peak wavelength in a wavelength region of 630 to 680 nm, and a peak wavelength in a wavelength region of 500 to 550 nm. A second phosphor that converts to light having
The light intensities emitted from the first phosphor and the second phosphor are configured to be approximately equal to each other,
The light intensity of the peak wavelength in the wavelength range of 630 to 680 nm and the light intensity of the peak wavelength in the wavelength range of 500 to 550 nm are higher than the light intensity of the peak wavelength in the wavelength range of 430 to 470 nm. ,
2. The white light emitting device according to claim 1, wherein the optical filter selectively reduces transmission of light in a wavelength region of 580 to 600 nm, and the transmittance of the optical filter is 50% or less.   A luminaire using the white light emitting device according to claim 1.

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