WO2021256307A1

WO2021256307A1 - Lighting device

Info

Publication number: WO2021256307A1
Application number: PCT/JP2021/021484
Authority: WO
Inventors: 直也増子; 英治石黒; 武川口; 啓一綿貫; 慶一村松
Original assignee: 株式会社朝日ラバー; 国立大学法人埼玉大学
Priority date: 2020-06-18
Filing date: 2021-06-07
Publication date: 2021-12-23
Also published as: JPWO2021256307A1; JP7281779B2

Abstract

This lighting device is an LED device component obtained by combining a plurality of phosphor-containing LED devices, wherein the phosphor-containing LED devices include a blue LED element, and a phosphor selected from an SAE-based phosphor, an LAG-based phosphor, and a silicate-based phosphor, and emit light of which the reflected light from PPC paper having an ISO whiteness of 82±3% has a correlated color temperature of 4500 to 7500 K and a color deviation duv of -0.01 to 0.02, wherein the spectral distribution of the emitted light includes: a first peak indicating a maximum intensity at a wavelength of 420 to 480 nm, and a second peak, which is the maximum peak at a wavelength of 481 to 580 nm, of which the ratio of the peak intensity to the intensity of the first peak is 40 to 70%, and of which the full width at half maximum is at least equal to 50; and a valley indicating an intensity of 5 to 17% of the intensity of the first peak, between the first peak and the second peak.

Description

Lighting equipment

The present invention relates to a lighting device which is an LED device configuration in which a plurality of LED devices are combined.

In recent years, in lighting using LED devices, research has been conducted on lighting that does not give a feeling of fatigue to people. For example, Patent Document 1 below describes the coordinate W (0.33) indicating an achromatic color in the coordinates of the chromaticity diagram of CIE1931 as a light source that emits light that makes the person feel bright in a dark place and gives high visibility and does not give a feeling of fatigue. , 0.33), the line segment WB connecting the 480 nm coordinate B (0.091, 0.133) on the spectral trajectory and the 560 nm coordinate G (0.373, 0.624), and the color purity in the region surrounded by the linear segment WG and the spectral trajectory. Disclosed discloses a light source that emits light that is included in the region of 2 to 50 and that the area occupied by continuous spectral wavelengths in the wavelength region of 480 to 540 nm is 15% or more of the spectral wavelength area of the entire light source of 380 to 780 nm. ..

Although it is not related to the feeling of fatigue, lighting that makes the characters on the paper easier to read by the light that enhances the whiteness of the paper has also been proposed. As such a technique, Patent Document 2 below includes a light source having a solid-state light emitting element, and the light source has a correlated color temperature in the range of 5400 to 7000K and a color deviation in the range of Duv-6 to 8, The CIE 1997. Disclosed is a lighting device having spectral radiation characteristics such that the chroma value, which is an index of vividness in copy paper, obtained by using the calculation method specified by Interim Color Appearance Model (Simple Version) is 2.7 or less.

JP-A-2019-125777 Japanese Unexamined Patent Publication No. 2014-075186

The inventors have found that in a lighting device using an LED device that emits white light, when reading characters on paper in a dark room, the eyes become tired, and the focus adjustment function of the eyes deteriorates, resulting in blurring of the characters. As a result of discovering the problem that it becomes difficult to visually recognize and diligently studying to solve such a problem, the present invention was conceived.

That is, an object of the present invention is to provide a lighting device that emits white light using an LED device, in which a person reading characters in a dark room does not easily deteriorate the focus adjustment function of the eyes.

One aspect of the present invention is an LED device configuration in which at least two fluorescent substance-containing LED devices are combined, and the fluorescent substance-containing LED device is a blue LED element that emits light having a peak wavelength in the range of 420 to 480 nm. , At least one fluorescent substance selected from the group consisting of SAE-based phosphors, LAG-based phosphors, and silicate-based fluorescent substances, which are excited by the light emission and emit fluorescence, and have an ISO whiteness of 82 ± 3. % PPC (plain paper copier) The reflected light on the paper surface (hereinafter, also simply referred to as the reflected light on the paper surface) has a correlation color temperature of 4500 to 7500 K and a color deviation duv of −0. The first peak showing maximum intensity in the wavelength range of 420 to 480 nm and the maximum peak in the wavelength range of 481 to 580 nm in the visible light region whose spectral distribution is 01 to 0.02 and whose spectral distribution is 380 to 780 nm. It has a second peak in which the ratio of the intensity of the peak to the intensity of the first peak is 40 to 70% and the half price range is 50 or more, and the first peak and the second peak. A light emitting illuminator having a valley in between that exhibits an intensity of 5 to 17% with respect to the intensity of the first peak. According to such a lighting device, it is possible to obtain a lighting device that emits white light and does not easily deteriorate the focus adjustment function of the eyes for a person who reads characters in a dark room.

Further, the phosphor-containing LED apparatus efficiently excites SAE-based phosphors, LAG-based phosphors, and silicate-based phosphors by containing at least one light diffusing material selected from the group consisting of silica and calcium carbonate. It is preferable from the viewpoint that it is easy to adjust so that the above-mentioned spectral distribution of the reflected light on the paper surface can be obtained by appropriately reducing the intensity of the emission of blue light having a wavelength of 420 to 480 nm.

Further, the paper reflected light has a spectral wavelength area of 15 to 30% in the wavelength region of 420 to 480 nm with respect to the spectral wavelength area of the visible light region having a wavelength of 380 to 780 nm, and the first is 581 to 780 nm. Not having a peak showing an intensity of 30% or more with respect to the intensity of the peak does not reduce the visibility of the character of a person who reads the character in a dark room, and it is difficult to give the person a feeling of eye fatigue. , It is preferable because it does not cause drowsiness.

Such a lighting device is preferably used for a reading light, a spotlight lighting, a desk lamp, an automobile interior light, or the like, which is used when reading characters in a dark room.

According to the present invention, in a lighting device that emits white light, it is possible to obtain a lighting device that does not easily reduce the focus adjustment function of the eyes for a person reading characters in a dark room.

FIG. 1 is a schematic plan view of the lighting device 100 of the embodiment. FIG. 2 is a diagram showing a range in which the correlated color temperature in the chromaticity coordinates of the light reflected on the paper surface by the light emitted by the lighting device of the embodiment is 4500 to 7500 K and the color deviation duv is −0.01 to 0.02. FIG. 3 is a schematic plan view of the phosphor-containing LED device 10. FIG. 4 is a schematic cross-sectional view of the phosphor-containing LED device 10. FIG. 5 shows the chromaticity coordinates of the light reflected on the paper surface due to the light emission of the lighting device obtained in each Example and each Comparative Example. FIG. 6 shows the spectral spectrum of the light reflected on the paper surface due to the light emitted from the lighting apparatus obtained in Examples 1 to 4. FIG. 7 shows the spectral spectra of the light reflected on the paper surface due to the light emitted by the lighting apparatus obtained in Comparative Examples 1 to 6. FIG. 8 is an explanatory diagram for explaining the lighting device used in the embodiment. FIG. 9 shows an explanatory diagram of the LED tabletop stand 50 for evaluation used in the examples.

The illumination device of the present embodiment is an LED device configuration in which at least two fluorescent substance-containing LED devices are combined, and the fluorescent substance-containing LED device is a blue LED element that emits light having a peak wavelength in the range of 420 to 480 nm. And at least one fluorescent material selected from the group consisting of SAE-based phosphors, LAG-based phosphors, and silicate-based phosphors, which are excited by the light emission of the blue LED element to emit fluorescence. Then, in the lighting device, the reflected light on the surface of PPC paper having an ISO whiteness of 82 ± 3% has a correlated color temperature of 4500 to 7500K and a color deviation duv of −0.01 to 0 in the chromaticity coordinates of CIE1931. It is 0.02, and in the visible light region having a spectral distribution of 380 to 780 nm, the first peak showing the maximum intensity in the wavelength range of 420 to 480 nm and the first peak showing the maximum intensity in the wavelength range of 481 to 580 nm. It has a second peak in which the ratio of the intensity of the peak to the intensity of the light is 40 to 70% and the half price range is 50 or more, and the first peak is between the first peak and the second peak. It emits light with valleys showing an intensity of 5-17% relative to the intensity of the peak.

As an example of the lighting device according to the present invention, an embodiment will be described with reference to the drawings. FIG. 1 is a schematic plan view of the lighting device 100 of the present embodiment, in which 10 is an LED device and 20 is an LED mounting board on which the LED device is mounted. A plurality of LED devices 10 are mounted on the main surface of the LED mounting board 20, and a power supply circuit 21 for supplying power to the plurality of LED devices 10 is formed on the back surface thereof. Further, a reflective film for diffusing light may be formed on the main surface of the LED mounting substrate 20. The power supply circuit 21 is connected to the power supply 30. Then, the plurality of LED devices 10 emit light when the power is supplied from the power source 30 through the power supply circuit 21.

In the lighting device 100, the reflected light on the surface of PPC paper having an ISO whiteness of 82 ± 3%, which is a high-quality paper having a standard whiteness, has a correlated color temperature of 4500 to 7500K in the chromaticity coordinates of CIE1931. The color deviation duv is in the range of -0.01 to 0.02, and the spectral distribution is the first peak showing the maximum intensity in the wavelength range of 420 to 480 nm in the visible light region having a wavelength of 380 to 780 nm. The second peak has a ratio of the intensity of the peak to the intensity of the first peak, which is the maximum peak in the wavelength range of 481 to 580 nm, of 40 to 70%, and the half price range is 50 or more. It emits white light with a valley between the first peak and the second peak that exhibits an intensity of 5 to 17% with respect to the intensity of the first peak. The chromaticity coordinates and spectral distribution of CIE 1931 of the reflected light on the paper surface are measured using, for example, a spectral irradiance meter (spectral irradiance meter CL-500A manufactured by Konica Minolta Co., Ltd.) as described later.

PPC paper with ISO whiteness of 82 ± 3% is high-quality paper with standard whiteness. The ISO whiteness is an index showing the whiteness of paper calculated by the measurement method specified in JIS P8148. The higher the ISO whiteness, the higher the whiteness.

The lighting of the lighting device of the present embodiment is adjusted so that the characteristics of the reflected light on the paper surface, which is reflected on the paper surface and stimulates the human eye, are within the above-mentioned range, so that the lighting emits white light. In the device, a lighting device that does not easily deteriorate the focus adjustment function of the eyes can be obtained for a person who reads characters in a dark room. FIG. 2 shows that the reflected light on the surface of PPC paper having an ISO whiteness of 82 ± 3% due to the light emitted by the lighting device has a correlated color temperature of 4500 to 7500K and a color deviation duv of −0 in the chromaticity coordinates of CIE1931. The range of 0.01 to 0.02 is shown.

Further, the light emission of the lighting device of the present embodiment has a first peak in which the spectral distribution of the above-mentioned paper reflected light shows the maximum intensity in the wavelength range of 420 to 480 nm in the visible light region having a wavelength of 380 to 780 nm. The maximum peak in the wavelength range of 481 to 580 nm, the second peak having a ratio of the peak intensity to the intensity of the first peak of 40 to 70% and a half width of 50 or more. The spectral characteristics are adjusted so as to have a valley between the first peak and the second peak, which exhibits an intensity of 5 to 17% with respect to the intensity of the first peak. The wavelength of the first peak is the wavelength of the peak of the mountain showing the maximum intensity in the wavelength region of 420 to 480 nm. The wavelength of the second peak is the wavelength of the peak of the mountain showing the maximum intensity in the wavelength region of 481 to 580 nm. The half-value width of the peak is the wavelength width of the portion where the intensity is half the intensity with respect to the intensity at the apex of each peak.

FIG. 6 shows the spectral spectrum of the paper reflected light of the lighting device obtained in Examples 1 to 4 described later according to the lighting device of the present embodiment. In each spectral spectrum, 11 (11a to 11d) is the first peak showing the maximum intensity in the visible light region having a wavelength of 380 to 780 nm, and is present in the region having a wavelength of 420 to 480 nm. Further, in 12 (12a to 12d), the ratio of the peak intensity to the intensity of the first peak, which is the maximum peak in the wavelength region of 481 to 580 nm, is 40 to 70%, and the half width is 50 or more. It is the peak of 2. Further, 13 (13a to 13d) is a valley existing between the first peak 11 and the second peak 12 and showing an intensity of 5 to 17% with respect to the intensity of the first peak 11.

The reflected light on the paper shows the light color in the range where the correlated color temperature is 4500 to 7500K and the color deviation duv is -0.01 to 0.02 in the chromaticity coordinates of CIE1931, and the spectral spectrum as described above is obtained. By having it, a lighting device that emits white light that does not give a person a sense of discomfort in light color can be obtained.

With respect to the color of the reflected light on the paper, the correlated color temperature is 4500 to 7500K, the color deviation duv is −0.01 to 0.02, preferably the correlated color temperature is 5000K to 6000K, and the color deviation duv is −0. It is 0.01 to 0.01, more preferably the correlated color temperature is 5000K to 6000K, and the color deviation duv is −0.01 to 0. According to a lighting device in which the light reflected on the paper surface has such a color, it is possible to obtain a lighting device that emits white light that does not give a person a sense of discomfort in the light color. When the correlated color temperature of the color of the reflected light on the paper exceeds 7500K, when the correlated color temperature is less than 4500K, when the color deviation duv is lower than -0.01, and when the color deviation duv exceeds 0.02. In some cases, the distance from the white region gives a person a sense of discomfort in the light color. Here, the color deviation duv indicates the color difference from the black body locus indicating the correlated color temperature in the chromaticity coordinates of CIE 1931, and when the color deviation becomes large on the plus side, the light color becomes greenish and becomes on the minus side. The smaller it becomes, the more reddish purple it becomes.

Further, regarding the color of the reflected light on the paper surface, in the visible light region having a wavelength of 380 to 780 nm, the first peak showing the maximum intensity is obtained in the region having a wavelength of 420 to 480 nm, and the intensity of the second peak is the first peak. When the intensity is 40 to 70%, preferably 40 to 60%, it is difficult for a person reading a character in a dark room to deteriorate the focus adjustment function of the eyes and to make the eyes feel tired. Further, the fact that the half-value width of the second peak is 50 or more, preferably the half-value width is 50 to 250, and more preferably the half-value width is 100 to 200, lowers the eye focus adjustment function for a person reading characters in a dark room. Make it difficult to make.

Further, the paper reflected light has an intensity of 5 to 17%, preferably 6 to 16%, and more preferably 8 to 15% with respect to the intensity of the first peak between the first peak and the second peak. Has a valley that indicates. Here, the valley existing between the first peak and the second peak means the point where the intensity between the first peak and the second peak is the lowest. Since the valley has a certain range of strength in this way, it makes it difficult for a person reading a character in a dark room to deteriorate the focus adjustment function of the eyes.

Further, in the spectral distribution of the paper reflected light, the spectral wavelength area in the wavelength region of 420 to 480 nm is 15 to 30%, and further 20 to 30% with respect to the spectral wavelength area in the visible light region having a wavelength of 380 to 780 nm. In addition, the fact that there is no peak showing an intensity of 30% or more, and further 40% or more with respect to the intensity of the first peak in the wavelength range of 581 to 780 nm makes the characters on the paper in a dark room. It is preferable because it does not reduce the visibility of the characters of the reader and does not cause drowsiness. Having a peak that is too large in the wavelength range of 581 to 780 nm tends to cause drowsiness.

As described above, the lighting device of the present embodiment is an LED device configuration in which at least two LED devices are combined on an LED mounting substrate. Even if the at least two LED devices used in such a lighting device are a combination of a plurality of one type of LED devices having similar light emission characteristics, a plurality of multiple types of LED devices showing different light emission characteristics are used. It may be a combination, and is appropriately selected according to the illuminance of the required application, the irradiation area, and the like. The number of at least two LED devices mounted on the lighting device is, for example, preferably in the range of 5 to 1000, more preferably 5 to 200.

Each LED device constituting at least two LED devices includes a phosphor-containing LED device in which a blue LED device including a blue LED element is combined with a phosphor as described later, which has the above-mentioned characteristics. It is preferable because it is easy to manufacture a lighting device that emits light that generates light reflected on the paper surface. Next, a typical example of the phosphor-containing LED device mounted on such a lighting device will be described with reference to the drawings.

FIG. 3 is a schematic plan view of a phosphor-containing LED device 10 for constituting the lighting device 100 of the present embodiment. Further, FIG. 4 is a schematic cross-sectional view taken along the line BB'of the phosphor-containing LED device 10 of FIG. Referring to FIGS. 3 and 4, the fluorescent substance-containing LED device 10 of the present embodiment contains the fluorescent substance 3 and a light diffusing material in which the LED device main body 5 including the blue LED element 1 is blended as needed. It is an LED apparatus structure manufactured so as to cover with a fluorescent substance-containing cap 9 which is a fluorescent substance layer.

As shown in FIG. 4, the LED device main body 5 is housed in a blue LED element 1 having an emission peak wavelength in the range of 420 to 480 nm, a package member 2 having a recess 2a for accommodating the blue LED element 1, and a recess 2a. It is a blue LED device including a transparent resin encapsulant 4 for encapsulating the blue LED element 1.

The blue LED element 1 emits light having an emission peak wavelength in the blue region of 420 to 480 nm. Since the LED device main body 5 includes the blue LED element 1, it is preferable because it forms a first peak showing the maximum intensity in the wavelength range of 420 to 480 nm in the spectral distribution of the reflected light on the paper surface. The blue LED element can obtain high luminous efficiency of the phosphor and is also excellent in long-term reliability.

Examples of the blue LED element include a gallium nitride (GaN) -based blue LED element. Further, the transparent resin encapsulant seals and seals the blue LED element housed in the recess. Examples of the transparent resin forming the transparent resin encapsulant include silicone resin, epoxy resin, and acrylic resin. The LED device main body 5 of the present embodiment is a type called a surface mount type device (SMD), but instead of the SMD, other types such as a so-called bullet type, a package type, and a chip-on-board type (COB type) are used. LED device may be used.

A reflective film 7 made of silver plating or the like may be formed on the inner wall surface of the recess 2a of the LED device main body 5. One electrode of the blue LED element 1 is connected to the lead 2b, and the other electrode of the blue LED element 1 is wire-bonded by a gold wire 6 and connected to the lead 2c, and each of them extends to the outside. Lead 2b is the anode and lead 2c is the cathode. The blue LED element 1 emits light by connecting the positive electrode side of the power supply to the lead 2c of the LED device main body 5 and the negative electrode side of the power supply to the lead 2b to apply electric power. In such an LED device main body 5, the upper surface of the transparent resin encapsulant 4 serves as a light emitting surface. A phosphor-containing cap 9 is attached so as to cover the light emitting surface of the LED device main body 5.

The phosphor-containing cap 9 is a fluoropium-activated strontium-aluminate (SAE) -based phosphor, a lutetium-aluminum-garnet phosphor, or a cerium-activated lutetium-aluminum-garnet phosphor that is excited by the emission of a blue LED element to emit fluorescence. It is a molded body obtained by molding a phosphor sheet containing at least one fluorescent substance selected from the group consisting of LuAG (LAG) -based fluorescent substances such as LuAG (LAG) -based fluorescent substances and silicate-based fluorescent substances such as chlorosilicate fluorescent substances into a cap shape.

Specific examples of the light-transmitting resin include silicone rubber (silicone elastomer) and silicone resin.

As described above, the SAE-based phosphor, the LAG-based phosphor, and the silicate-based phosphor have a fluorescence peak wavelength having a half-value width of 50 or more in the wavelength range of 430 to 530 nm. It is preferable because it is easy to obtain a phosphor-containing LED device that emits light that becomes reflected light on a paper surface having a spectral distribution.

Further, the fluorescent substance-containing cap 9 may contain a fluorescent substance other than the above-mentioned fluorescent substance, if necessary. Specific examples of such a fluorescent substance include, for example, an aluminate-based fluorescent substance, an yttrium aluminum garnet-based fluorescent substance (YAG-based fluorescent substance) such as an active yttrium aluminum garnet fluorescent substance with cerium, and β-SiAlON: Eu (sialon-based). Fluorescent materials that emit fluorescence in the bluish green to yellow region such as fluorescent materials) can be mentioned.

A fluorescent substance having a peak wavelength in the range of 481 to 530 nm mainly emits blue to blue-green fluorescence, and a fluorescent substance having a peak wavelength in the range of 500 to 590 nm mainly emits blue-green to yellow fluorescence.

Further, in the phosphor-containing cap, in order to improve the color rendering property, a phosphor that is excited by the light emission of the blue LED element and emits reddish light having a peak wavelength in the range of 581 to 780 nm is provided. It may be blended. However, the spectroscopy of peaks in the wavelength range of 581 to 680 nm due to the fluorescence of red-based phosphors tends to cause drowsiness. Specific examples of such a red phosphor include a nitride-based phosphor, a Cousin-based phosphor (CASN phosphor) such as _{(Sr, Ca) CaAlSiN 3} : Eu, and CaAlSiN _{3: Eu, and a sialone-based phosphor.} Can be mentioned.

Further, the phosphor-containing cap efficiently excites the phosphor in the phosphor-containing cap by diffusing the light of the blue LED element having a wavelength of 420 to 480 nm, and the intensity of blue light emission having a wavelength of 420 to 480 nm. It is preferable to add a light diffusing material in order to appropriately reduce the amount of light. Examples of such a light diffusing material include silica and calcium carbonate.

Further, the phosphor-containing cap may contain a coloring material as necessary as a component for adjusting the emission color by absorbing light having a predetermined wavelength. Specific examples of such a coloring material include organic or inorganic pigments such as chrome green, chromium oxide, pigment green B, malachite green lake, fanal yellow green G, and phthalocyanine green as green pigments. Further, in order to adjust the brightness of the entire light source, a white pigment such as titanium oxide, talc and barium sulfate, and a black pigment such as carbon black can be used in combination. These may be mixed with a fluorescent substance or may be blended by providing a layer containing no fluorescent substance.

Further, instead of the above-mentioned phosphor-containing cap, a flat fluorescent material-containing fluorescent sheet is adhered, or a fluorescent material-containing phosphor layer is provided on the light emitting surface of the LED device main body to provide a fluorescent substance-containing LED device. May be manufactured. The phosphor layer may be in the form of a film formed on the surface of the blue LED element or formed by coating or printing on the inside or the surface of the transparent resin encapsulant. In particular, when the phosphor layer is in the form of a film formed on the surface of the transparent resin encapsulant, the amount of the phosphor and the light color adjusting agent blended in the phosphor layer, and the fine adjustment of the spectral wavelength and the emission intensity are finely adjusted. , It is preferable from the viewpoint that the manufacturing of the LED device becomes easy. Further, in the phosphor-containing LED device, instead of forming the phosphor layer, the phosphor may be dispersed in a transparent resin encapsulant that encloses the blue LED element.

The lighting device, which is a structure that combines at least two LED devices, has been described in detail above. The lighting device is not limited to the above-described configuration, and may include or modify additional elements as long as the reflected light on the paper surface has the above-mentioned spectral characteristics. Specifically, for example, as an LED device, a blue LED device containing a blue LED element that does not contain a phosphor, an ultraviolet LED device having a wavelength of 360 nm to 400 nm, a color filter that adjusts the spectral wavelength of the LED device, and a color. A light diffusing member for extracting even light, a light guide member for controlling the light distribution, and a lens member may be combined as necessary.

The lighting device of the present embodiment described above is a specific application of indirect lighting used when reading characters in a dark room such as 20 lux or less, where external light does not affect the spectral spectrum of the reflected light on the paper surface. For example, it is preferably used as an internal lighting such as a reading light, a spotlight lighting, a table lamp, a desk light, a ceiling light, an automobile, a vehicle, a ship, or an airplane interior map lamp or a vehicle interior light.

Hereinafter, the present invention will be specifically described with reference to examples. The scope of the present invention is not limited to the examples.

[Fluorescent material]
The phosphors used in this example are summarized in Table 1 below.

[Manufacturing of LED devices]
A silicone rubber composition containing a fluorescent substance in which the fluorescent substances F1 to F7 and the light diffusing material D (calcium carbonate) shown in Table 1 were uniformly dispersed in the silicone rubber at the blending ratio shown in Table 2 below was prepared, and each of them was prepared. The composition was hot press molded to produce phosphor-containing caps C1 to C10 having a thickness of 0.3 mm.

Then, any of the phosphor-containing caps (C1 to C10) was adhered to the light emitting surface of the blue LED device with a silicone-based adhesive to manufacture the fluorescent substance-containing LED devices L1 to L10.
As the blue LED device, B1 "NJSC172C (emission peak: 443 nm)" or B2 "NSSC063A (emission peak: 452 nm)") (both manufactured by Nichia Corporation) was used.

[Manufacturing of lighting equipment]
As shown in FIG. 8, the phosphor-containing LED devices L1 to L10 shown in Table 2 are mounted on a regular hexagonal LED mounting substrate 21 having a diagonal length of 20 mm and capable of mounting three fluorescent substance-containing LED devices L. I implemented 3 of the same type. In this way, a large number of LED mounting boards S (S1 to S10) on which three LED devices of the same type are mounted are manufactured. Then, as shown in FIG. 8, any one of the mounting substrates S1 to S10 was adhered to one surface of a rectangular aluminum plate 22 having a thickness of 1 mm and a thickness of 75 × 200 mm with 10 pieces of the same type with a heat-dissipating silicone-based adhesive. Ten mounting boards of the same type were bonded to one aluminum plate at equal intervals, and a total of 30 mounting boards were mounted. Then, wiring was performed to supply electric power to each mounting board. In this way, the lighting device 110, which is an LED device configuration in which 30 fluorescent substance-containing LED devices are mounted on an aluminum plate, is manufactured.

[Manufacturing of LED countertop]
Any of the above-mentioned lighting devices 110 was attached to the aluminum frame 15 which is a reflective member to which the heat exhaust fins 14 are attached. Then, as shown in FIG. 9, the LED tabletop stand 50 was manufactured by supporting the aluminum frame 15 on the support column 16. The height of the aluminum frame 15 is adjusted by sliding it along the support column 16.

In addition, the evaluation methods used in this example will be summarized below.

[Evaluation of optical characteristics of light source]
The LED tabletop stand described above was placed on a table having a square surface of 400 × 400 mm. At this time, the height from the light emitting surface of the phosphor-containing LED device of the LED tabletop stand to the square surface is the spectral irradiance meter (CL- manufactured by Konica Minolta Co., Ltd.) on the table when the light source is turned on. The illuminance measured at 500A) was adjusted to 400 mm, which is 500 lux.

Then, PPC paper having an ISO whiteness of 82% was placed on the table. Then, the light source of the LED desk stand was turned on to illuminate the PPC paper. Then, the reflection spectrum and the chromaticity coordinates of the light reflected on the paper surface from the surface of the PPC paper were measured using a spectral irradiance meter.

The evaluation results are shown in Table 3 below. At the same time, Table 3 also shows the tint specified from the chromaticity (x, y) coordinates. The first peak indicates the wavelength of the first peak in the region of 420 to 480 nm. The intensity ratio indicates the intensity ratio of the second peak to the first peak. The spectral wavelength region area ratio indicates the area of the spectral wavelength of 420 to 480 nm when the area of the spectral wavelength of 380 to 780 nm is 100%. The presence or absence of a peak having an intensity of 30% or more with respect to the intensity of the first peak is also shown in the wavelength range of 580 to 780 nm.

Further, FIG. 5 shows the chromaticity coordinates of CIE 1931 of the light reflected on the paper surface due to the emission of the lighting device obtained in each Example and each Comparative Example. Further, FIG. 6 shows the spectral spectra of the reflected light on the paper surface due to the light emitted by the lighting devices obtained in Examples 1 to 4, and FIG. 7 shows the spectral spectra of the reflected light on the paper surface obtained by the light emitted by the lighting devices obtained in Comparative Examples 1 to 6. show.

[evaluation]
Ten subjects aged 21 to 24 years were recruited. The subjects had visual acuity of 0.7 or higher in both eyes when wearing naked eyes, regular spectacles, or contact lenses, and had no color vision deficiency evaluated by the Ishihara normal color vision test chart. Subjects wearing regular eyeglasses or contact lenses were allowed to wear them. In addition, the subjects had sufficient sleep for 6 hours or more on the day before the experiment, did not smoke or drink within 12 hours after the start of the experiment, and did not ingest caffeine within 1 hour after the start of the experiment. Then, in the dark room, a table and a chair having a square surface of 400 × 400 mm were arranged, and the above-mentioned LED tabletop stand was arranged on the table. Then, the heights of the table and the chair were adjusted so that the viewing distance between the printed matter placed on the table and the subject when the subject sat on the chair was 450 mm, and the positions of the eyes were adjusted. The purpose of the experiment was not communicated to the subjects.

After the subject was seated in a chair in a dark room to maintain a rest time of 1 minute, the adaptive light source with chromaticity of emission (0.33, 0.33) and illuminance of 100 lux was turned on. Then, the subjects were asked to answer the question of subjective symptom and the question of subjective symptom of eye strain as follows.

<Survey of subjective illness>
Using the "subjective symptom survey" shown in Table 4 below published by the Japan Society for Occupational Health Industrial Fatigue Study Group (2002), each subject was asked to judge the subjective symptoms of drowsiness, instability, and blurring. From the items in Table 3, drowsiness refers to the scores of 10,13,14,17,21, instability refers to the scores of 2,5,15,18,20, and blurring refers to the scores of 3,7. , 16, 22, 24 scores were referred to, and the respective scores were totaled.

<Subjective symptoms of eye strain>
The subjects were asked to judge the subjective symptoms of eye strain according to the criteria shown in Table 5 below based on the description in "New Industrial Fatigue Handbook" pp.362-363 (1995) published by the Japan Society for Occupational Health and Industrial Fatigue Research Institute. .. And the scores were totaled.

<Measurement of flicker value>
Then, the flicker value was measured for the subject. Specifically, the critical fusion frequency was measured three times in the forward and reverse directions using a labor laboratory digital flicker value measuring device (RDF-1 manufactured by Shibata Scientific Technology Co., Ltd.), and the average value was obtained. The critical fusion frequency (CFF) decreases as fatigue and drowsiness increase.

<Focus adjustment power (near point adjustment power)>
Next, the perigee distance of the eyes was measured. Specifically, using a perigee meter (NS-100 manufactured by Towa Co., Ltd.), the perigee distance was measured alternately for each eye five times, and the average perigee distance was obtained from the average value. Then, the near-point accommodation force (D) = 1 / average near-point distance was calculated to calculate the near-point accommodation force. As the eye fatigue increases, the accommodation capacity decreases.

<Measurement of change in oxyHb concentration>
Then, after a rest period of 1 minute, the adaptive light source was turned off, and measurement of the change signal of the oxyHb concentration in the medial part of the prefrontal cortex by near-infrared spectroscopy (NIRS) was started. A wearable optical topography device using NIRS (WOT-220 manufactured by Hitachi High-Technologies Corporation) was attached to the head of the subject in accordance with the International 10-20 Law, and an electrode was attached to the medial part of the prefrontal cortex, which is between Fp1 and Fp2. Then, near-infrared light (about 700 to about 1500 nm) was applied to the brain from the scalp of the subject. Then, the subject was turned on the evaluation light source of the LED tabletop stand equipped with the evaluation light source, and the printed matter arranged in advance on the table was silently read for 10 minutes. The printed matter was printed on A4 PPC paper, in which the font was Mincho and the characters with a font size of 10.5 were 40 characters x 36 lines and Japanese sentences were printed. Then, the change signal of the oxyHb concentration during silent reading of the printed matter was measured, and the average value of the oxyHb concentration was calculated. The oxyHb concentration decreases during fatigue in the medial prefrontal cortex, and a decrease in the oxyHb concentration indicates a decrease in the brain activation response. Then, the evaluation light source of the LED table stand was turned off, and the measurement of NIRS was completed after a rest time of 1 minute.

Then, the adaptive light source was turned on, and the perigee distance and the flicker value of the eyes were measured again in the same manner as described above. In addition, the subjects were asked to answer the question of subjective symptom examination and the question of subjective symptom of eye strain again. In addition, they were asked to answer the question of visibility (easiness of reading characters) when the printed matter was silently read for 10 minutes according to the criteria shown in Table 6.

Each evaluation result was judged based on the case where the light source of Comparative Example 1, which is general pure white light, was used.
A: Score superior to the standard (Comparative Example 1) B: Equivalent to the standard (Comparative Example 1) C: Score inferior to the standard (Comparative Example 1)

The above evaluation results are summarized in Table 3.

Referring to FIGS. 5, 6 and 3, the lighting devices obtained in Examples 1 to 4 have a correlated color temperature of 4500 to 7500 K and a color deviation duv of −0.01 to 0 in all of the lighting devices obtained in Examples 1 to 4. It shows the light emission contained in 0.02, and the spectral characteristics of the reflected light on the paper surface satisfy the scope of the present invention.

Then, referring to Table 3, the lighting devices obtained in Examples 1 to 4 were superior in focus adjusting power to the lighting devices of Comparative Examples 1 to 5. Specifically, the intensity of the valley between the first peak and the second peak of the reflected light on the paper surface is less than 5% with respect to the intensity of the first peak, or a SAE-based phosphor or a LAG-based phosphor. , And the illuminating devices obtained in Comparative Examples 1 and 3 to 5 containing no silicate-based phosphor were inferior in focus adjusting power in a dark place as compared with the illuminating devices obtained in Examples 1 to 4. Further, in Comparative Example 2, which contains a LAG-based phosphor, the intensity of the valley between the first peak and the second peak of the reflected light on the paper surface is more than 17% with respect to the intensity of the first peak. The obtained lighting device was also inferior in focus adjustment ability in a dark place. The lighting device obtained in Comparative Example 6 in which the intensity of the valley between the first peak and the second peak of the paper reflected light is less than 5% with respect to the intensity of the first peak is a dark place. Although the focus adjusting force in the above was equivalent to that of Examples 1 to 4, the visibility was inferior.

1 Blue LED element 3 Fluorescent body 5 LED device body 9 Fluorescent substance-containing cap 10 Fluorescent substance-containing LED device 11 First peak 12

Second peak

100, 110 Lighting device

Claims

An LED device configuration that combines at least two phosphor-containing LED devices.
The fluorescent substance-containing LED device includes a blue LED element that emits light having a peak wavelength in the range of 420 to 480 nm, and a europium-activated strontium-aluminate (SAE) -based phosphor that emits fluorescence excited by the light emission, LuAG. Includes (LAG) -based fluorophore and at least one fluorophore selected from the group consisting of silicate-based fluorophore.
The reflected light on the surface of PPC (plain paper copier) paper with ISO whiteness of 82 ± 3% is
In the chromaticity coordinates of CIE 1931, the correlated color temperature is 4500 to 7500K, the color deviation duv is -0.01 to 0.02, and
In the visible light region where the spectral distribution has a wavelength of 380 to 780 nm, the first peak showing the maximum intensity in the wavelength range of 420 to 480 nm and the peak with respect to the intensity of the first peak which is the maximum peak in the wavelength range of 481 to 580 nm. It has a second peak having an intensity ratio of 40 to 70% and a half width of 50 or more, and between the first peak and the second peak, the first peak It has a valley showing an intensity of 5 to 17% with respect to the intensity.
A lighting device characterized by emitting light.
The lighting device according to claim 1, wherein the half width is 80 or more.
The lighting device according to claim 1 or 2, wherein the reflected light on the paper surface has a correlated color temperature of 5000 to 6000 K and a color deviation duv of −0.01 to 0.01 in the chromaticity coordinates of CIE 1931.
The lighting device according to any one of claims 1 to 3, wherein the phosphor-containing LED device contains at least one light diffusing material selected from the group consisting of silica and calcium carbonate.
The paper reflected light has any one of claims 1 to 4 in which the spectral wavelength area in the wavelength region of 420 to 480 nm is 15 to 30% of the spectral wavelength area in the visible light region having a wavelength of 380 to 780 nm. The lighting device described in.
The lighting device according to any one of claims 1 to 5, which does not have a peak having an intensity of 30% or more with respect to the intensity of the first peak at a wavelength of 581 to 780 nm.
The lighting device according to any one of claims 1 to 6, which is a reading light, a spotlight lighting, a table lamp, or a vehicle interior light.