JP6707728B2 - White light source system for medical facility lighting - Google Patents

Description

The present invention relates to a white light source system characterized by being able to continuously and faithfully reproduce the emission spectrum shape and emission intensity of sunlight that change with the passage of time. In particular, it relates to a white light source system used for illumination of medical facilities.

In recent years, a light source using an LED (light emitting diode) has attracted attention from the viewpoint of energy saving and reduction of carbon dioxide emission. Compared with the conventional incandescent light bulb using a tungsten filament, it has a long life and can save energy, and because of its convenience, LED lighting is rapidly expanding its market. Many of the initial LED illuminations are of a type that obtains white light by combining a blue light emitting LED and a yellow light emitting phosphor, and it has been possible to reproduce only an unnatural white color that lacks warmth. However, the performance of LED products has been significantly expanded along with the market expansion, and various types of LED white light sources have been developed as a result of improvements in the combination of LEDs and phosphors.

For example, Patent Document 1 discloses a lighting fixture capable of reproducing five types of white light. Two types of LEDs that emit white light with a high color temperature and white light with a low color temperature are prepared by combining LEDs with various phosphors, and the light emission of these LEDs is mixed at various ratios to obtain the bulb color and temperature. It obtains five types of white light: white, white, neutral white, and daylight. By appropriately using such plural kinds of white light in indoor lighting, it is possible to obtain a lighting effect according to the purpose in various scenes of daily life.

On the other hand, in recent years, lighting has been developed that takes into consideration not only mere effects but also effects on the human body. First, there is a concern that the strong light emitted by the blue LED may adversely affect the human body, such as suppressing the hormone (melatonin) secretion of the human body. Therefore, lighting that reduces the influence of blue light has been proposed. For example, in Patent Document 2, the effect of blue light is reduced by adding a device of combining LEDs and phosphors having different emission peaks and mixing four types of emission peaks, instead of simply reducing the intensity of blue light. It also provides white light with little deviation from the spectral luminous efficiency.

The other one is a movement to actively utilize the LED light source for recovery and enhancement of physical strength. For example, it is an attempt to improve the health by reproducing sunlight that is friendly to the human body as it is and actively acting on the body clock of the human body. Patent Document 3 and Patent Document 7 are inventions relating to a white light source having an emission spectrum equivalent to that of sunlight, in which sunlight having different color temperatures is reproduced with a black body radiation spectrum having the same color temperature. According to the present invention, sunlight having various color temperatures is approximated including spectral shapes, and white illumination that can cope with the rhythm of the body clock can be obtained. Patent Document 4 is an invention relating to a control device that has means for detecting illuminance and temperature around the human body and adjusts lighting and air conditioning around the human body according to a biological rhythm based on the obtained data. Further, Patent Document 5 is an invention relating to an illumination system using a white light source, and the subject of illumination relates to office illumination or the like centering on a person or the like. It is a system that can adjust the color temperature and illuminance of indoor light while detecting the change of outdoor light, and can obtain white illumination corresponding to the physiological phenomenon of the human body and seasonal changes. Finally, Patent Document 6 is an invention relating to an artificial sunlight system in which a plurality of light emitting diode modules having different color temperatures are combined, and shows the time variation of the color temperature of sunlight radiated to points on the earth at different latitudes and longitudes. It can be reproduced.

JP, 2007-265818, A International publication WO2008/069101 pamphlet International publication WO2012/144087 pamphlet JP-A-8-193738 JP, 2011-23339, A Japanese Patent Publication No. 2009-540599 International publication WO2012/108065 pamphlet

In recent years, it has become possible to obtain various white lights by using an LED light source, and various attempts have been made to obtain an illumination effect equivalent to that of sunlight with an artificial white light source. However, even if the light emitting characteristics are the same as those of the sunlight, many of the characteristics are insufficient from the viewpoint of reproducing the sunlight only by approximating the characteristics on the surface. For example, Patent Document 6 is an invention relating to an artificial sunlight system, but reproduces the light emission characteristics of sunlight that change depending on time and place with reference to color temperature. However, even if only the color temperature is adjusted, the reproduction level of sunlight is not sufficient. This is because in order to truly reproduce sunlight, not only the mere color temperature but also the wavelengths and intensities of the respective luminescent components forming a specific color temperature need to be matched. In this respect, the artificial sunlight system of Patent Document 6 reproduces only the apparent emission color, and the reproduction level cannot be said to be sufficient. Further, Patent Document 5 is an invention relating to a lighting system that can respond to changes in sunlight in a natural environment. However, even in this invention, the illumination is controlled only by paying attention to the color temperature and the illuminance, and the reproduction level for sunlight is not sufficient.

On the other hand, Patent Literature 3 and Patent Literature 7 reproduce sunlight having different color temperatures with a black body radiation spectrum having the same color temperature. Since the sun can be regarded as one type of black body, and the shape of the black body radiation spectrum is approximated, from the viewpoint of the reproduction of sunlight, the most excellent method in the cited patent documents. Is. Further, according to the present invention, it is possible to reproduce a change in color temperature corresponding to a change in sunlight for one day. However, in the case of the present invention, although the light emission characteristics can be reproduced to some extent, the change in the light emission characteristics is not sufficient. Because it is possible to reproduce white light of various color temperatures, it is possible to reproduce a specific color temperature in a piecemeal manner, and not to continuously reproduce the color temperature change of sunlight.

The other patent documents are also the same in that the change in the light emission characteristic is reproduced. There are several patent documents that describe that white light with various color temperatures can be reproduced or changes in emission color can be reproduced, but as a specific method, white light with a specific color temperature is reproduced in pieces. Most methods are used. Among them, Patent Document 5 focuses on a change in the color temperature of sunlight and adopts an illumination method adapted to the change, but the change in the color temperature is only switched in units of time, and continuous. It's not a reproduction of the changes.

As described above, although various inventions have been disclosed as lighting capable of reproducing the emission characteristics of sunlight, the reproduction of the emission color or emission spectrum of sunlight is insufficient, or the emission color or emission spectrum changes. In the present situation, the situation is not continuously reproduced, or only one of the above-mentioned characteristics or both of the characteristics is insufficient.
An object of the present invention is to reproduce the light emission characteristics of sunlight whose color temperature and light emission spectrum distribution change from moment to moment in a white light source system and use it as illumination for medical facilities.

According to the present invention, there is provided a white light source system for medical facility illumination, which includes a plurality of white light sources having different color temperatures. The emission spectrum of each white light source is P(λ), the emission spectrum of black body radiation showing the same color temperature as each white light source is B(λ), and the spectral luminous efficiency spectrum is V(λ), P(λ)× When the wavelength at which V(λ) is maximum is λmax1 and the wavelength at which B(λ)×V(λ) is maximum is λmax2, (P(λ)×V(λ))/(P(λmax1)× The absolute value of the difference between V(λmax1)) and (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) satisfies the relational expression shown in Expression 1 below. When the color temperature of the white light emitted from the white light source system is changed by changing the mixing ratio of the light from multiple white light sources, the difference in the color temperature of the white light before and after the change is specified by the McAdam ellipse. Try to fit within the range. Thus, emission characteristics of the white light with rather boiled vary continuously with time, which is emitted from the system, emission aging characteristics of the white light, the result of the actual measurement from sunrise sunlight until sunset It is characterized in that it proceeds according to a pattern selected from a plurality of change patterns based on it.
The white light source used in the white light source system of the present invention has an emission spectrum shape equivalent to that of sunlight and combines at least two types of white light sources having different color temperatures to reproduce sunlight at various color temperatures. It is a thing. Each white light source used in the present invention, the visible light region of the sunlight has a light emitting component, at a level equivalent to that of the sunlight, mixed white light mixed with each white light source in any proportion, also, It can contain a light emitting component at a level similar to that of sunlight.

The white light source system of the present invention is not capable of reproducing white light between different color temperatures in a piecemeal manner, but is capable of continuously tracking and reproducing light emission characteristics that change with time. In the present invention, the daily change of sunlight at various points on the earth, and the annual change are controlled based on the data observed in advance to control the emission spectrum shape and intensity of the light source. It is possible to reproduce the changes. Therefore, without using a white light source with a specific color temperature continuously for a long time or artificially adjusting the color temperature and intensity changes of the white light source, it is extremely natural that it adapts to the circadian rhythm of the human body. Even the change in sunlight can be reproduced by the white light source system of the present invention.

Since the white light source system for medical facility lighting of the present invention can obtain natural light extremely close to sunlight, it can be used not only for applications such as high color rendering lighting, but also as bio-adaptive lighting that works on physiological phenomena of the human body. It is also expected to be applied to such fields. For example, in lighting used in medical facilities such as hospitals, it is necessary to use indoor lighting for a long period of time for hospital treatment by adopting lighting that takes into account changes in sunlight for one to one year. For patients who do not have this, it is expected that the rhythm of the body clock will be maintained appropriately and that the patients' reintegration into society will be promoted.

The figure which shows the spectrum of spectral luminous efficiency. The figure which shows the black body radiation spectrum of color temperature 5100K. FIG. 3 shows a spectrum of a white light source of the system of the present invention corresponding to the black body radiation spectrum of FIG. 2. The figure which shows (P((lambda))*V((lambda)))/(P((lambda)max1)*V((lambda)max1)) of the white light source of the system of this invention. The figure which shows (B((lambda))*V((lambda)))/(B((lambda)max2)*V((lambda)max2)) of the black body radiation of FIG. Difference spectrum based on FIGS. 4 and 5 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2) The figure which shows xV((lambda)max2)). The figure which shows the reproduction|regeneration area|region of the color temperature by the white light source system of this invention. The figure which shows the color temperature and illuminance change of the sunlight of one day in Tokyo, Japan in spring. FIG. 3 is a diagram showing an emission spectrum of the white light source of Example 1. FIG. 5 is a diagram showing (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) of the white light source of Example 1. FIG. 3 is a diagram showing an emission spectrum of black body radiation of Example 1. FIG. 5 is a diagram showing (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) of black body radiation of the first embodiment. Difference spectrum of Example 1 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2)×V( The figure which shows (lambda)max2)). FIG. 6 is a diagram showing (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) of the white light source of Example 2. FIG. 6 is a diagram showing (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) of black body radiation of the second embodiment. Difference spectrum of Example 2 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2)×V( The figure showing (lambda)max2)). FIG. 9 is a diagram showing (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) of the white light source of Example 3. FIG. 10 is a diagram showing (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) of black body radiation of the third embodiment. Difference spectrum of Example 3 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2)×V( The figure which shows (lambda)max2)). FIG. 10 is a diagram showing (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) of the white light source of Example 4. FIG. 11 is a diagram showing (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) of black body radiation of the fourth embodiment. Difference spectrum of Example 4 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2)×V( The figure which shows (lambda)max2)). FIG. 10 is a diagram showing (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) of the white light source of Example 5. FIG. 10 is a diagram showing (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) of black body radiation of Example 5. Difference spectrum of Example 5 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2)×V( The figure which shows (lambda)max2)). FIG. 16 is a diagram showing (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) of the white light source of Example 6. FIG. 16 is a diagram showing (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) of black body radiation of Example 6. Difference spectrum of Example 6 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2)×V( The figure which shows (lambda)max2)). FIG. 6 is a diagram showing (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) of the white light source of Comparative Example 1. FIG. 5 is a diagram showing (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) of black body radiation of Comparative Example 1. Difference spectrum (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)) between the white light source of Comparative Example 1 and the black body radiation spectrum of the corresponding color temperature. The figure which shows xV((lambda))/(B((lambda)max2)*V((lambda)max2)). FIG. 16 is a diagram showing a color temperature reproduction region by the white light source system according to the seventh embodiment. FIG. 16 is a diagram showing a color temperature reproduction region by the white light source system of Example 8. The figure which shows the color temperature and illuminance change of the sunlight of Japan, Okinawa, and Naha city in autumn in one day. The figure which shows the color temperature and illuminance change of the sunlight in Los Angeles, USA in the summer. FIG. 6 is a diagram showing a color temperature reproduction region by a white light source system of Comparative Example 2; The figure which shows the color temperature and illuminance change of sunlight of Japan, Hokkaido, and Wakkanai in spring. The figure which shows the color temperature and illuminance change of one day of sunlight in Taipei City, Taiwan in the summer. The figure which shows the color temperature and illuminance change of the sunlight of Japan, Hokkaido, and Wakkanai in summer. The figure which shows the color temperature and illuminance change of the sunlight of Japan, Okinawa, and Naha city in winter in one day. The figure which shows the color temperature and illuminance change of the sunlight of 1 day in Tokyo, Japan in winter. The figure which shows the color temperature and illuminance change of the sunlight of Japan, Hokkaido, and Wakkanai in winter. The schematic diagram of an example of the white light source system of an embodiment.

Hereinafter, embodiments will be described with reference to the drawings.
The white light source system for medical facility illumination according to the embodiment of the present invention includes a plurality of white light sources and a control unit that controls the plurality of white light sources. Each of the plurality of white light sources includes an LED module. The white light source system will be described below.

(Emission characteristics of white light source)
The white light source used in the system of the present invention basically reproduces sunlight having various color temperatures. That is, when reproducing sunlight having a specific color temperature, it is basically considered that a black body radiation spectrum having the same color temperature as that of sunlight is regarded as an emission spectrum due to sunlight and its shape is approximated. The sun can be considered as a type of black body, and the radiation spectrum curve of the black body and the emission spectrum curve of sunlight are in good agreement, and the actual spectral distribution of the sun's rays is 5800K in the black body radiation spectrum. It is said to be close.

However, the color temperature of the sunlight that reaches the earth changes from moment to moment. This is because the altitude of the sunlight seen from the earth periodically changes on a daily or annual basis due to the effects of the rotation and revolution of the earth. Since air, moisture, and various suspended matter are present on the surface of the earth, by the time sunlight reaches the surface of the earth, it collides with various particles while passing through these suspended matter layers, The light of the specific wavelength component is scattered. At this time, when the altitude of the sun seen from above the earth changes, the distance that the sunlight passes through the floating material layer changes, and the appearance of scattered light changes depending on the angle. Will appear. Usually, in the morning and the evening when the sun is low, white light of about 2000 to 4000K, and at noon when the sun's highest altitude is about 5000 to 6000K, and in the shade and cloudy sky, about 6000 to 7,000K. Is known to be.

In order to reproduce sunlight having various color temperatures as described above, in the white light source used in the system of the present invention, an emission spectrum approximated to a black body radiation spectrum having a color temperature range of 2000K to 8000K was synthesized. According to this temperature range, it is possible to substantially cover the color temperature range of sunlight that can be observed on the earth. The range of color temperature often used as an illumination light source is narrower, and is in the range of 2000K to 6500K.

By the way, the above-mentioned black body radiation spectrum can be obtained by Planck's formula shown in the following equation (1). In the formula, h is Planck's constant, k is Boltzmann's constant, c is the speed of light, and e is the base of the natural logarithm. Since it is fixed at a constant value, if the color temperature T is determined, it corresponds to each wavelength (λ). The spectral distribution B(λ) can be easily obtained.

The white light source used in the system of the present invention is specifically defined as follows. The emission spectrum of each white light source is P(λ), the emission spectrum of black body radiation showing the same color temperature as the white light source is B(λ), and the spectral luminous efficiency spectrum is V(λ), P(λ)×V. Assuming that the wavelength having the maximum (λ) is λmax1 and the wavelength having the maximum B(λ)×V(λ) is λmax2, (P(λ)×V(λ))/(P(λmax1)×V The absolute value of the difference between (λmax1)) and (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) satisfies the following formula (2). It is desirable that the absolute value satisfy the following formula (2) at each wavelength.

Furthermore, it is desirable that the white light source used in the system of the present invention satisfy the following expression (3) in the sense that the emission spectrum of black body radiation is reproduced more strictly.

The above definitions will be specifically described with reference to the drawings. FIG. 1 is a diagram showing a spectrum of spectral luminous efficiency. It can be seen that a spectral distribution corresponding to the sensitivity of the human eye shows a symmetrical spectral distribution having the maximum sensitivity at about 555 nm.

FIG. 2 is a black body radiation spectrum corresponding to sunlight having a color temperature of 5100K, and FIG. 3 is an emission spectrum of a white light source used in the system of the present invention which is approximated to a black body radiation spectrum of 5100K. Comparing the two, it can be seen that the two emission spectrum shapes are in good agreement in the wavelength region of 450 nm to 650 nm. At wavelengths below 450 nm and above 650 nm, the spectral distributions of the two differ greatly, but these wavelength ranges are regions with little sensitivity to the human eye, as can be seen from FIG. There is no problem. The emission spectrum of the light source used in the system of the present invention includes that shown in FIG. 3, for example. The emission spectrum illustrated in FIG. 3 is a combination of the emission spectra of a light emitting diode (LED) and a phosphor as described later, and by appropriately adjusting the emission spectra of three or more types of phosphors, a black body It can be approximated to the spectral shape of radiation.

4 and 5 show the emission spectra of FIGS. 3 and 2 multiplied by the spectral luminous efficiency. The spectrum shown in FIG. 4 is an emission spectrum represented by (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) of the white light source used in the system of the present invention. FIG. 5 shows an emission spectrum of black body radiation represented by (B(λ)×V(λ))/(B(λmax2)×V(λmax2)). Further, FIG. 6 shows a difference spectrum between both spectrum distributions of FIG. 4 and FIG. 5, and specifically, the formula (P(λ)×V(λ))/(P(λmax1)×V(λmax1) )-(B(λ)×V(λ))/(B(λmax2)×V(λmax2)). As can be seen from the difference spectrum of FIG. 6, the absolute value of the difference between the spectra between the two is 0.05 or less at each wavelength in the range of 350 nm to 800 nm, and the equation (3) shown in the following Equation 5 is used. It can be seen that the relationship is satisfied.

(LED module)
The white light source used in the system of the present invention comprises an LED module. The LED module preferably includes a light emitting diode (LED) and a phosphor. The phosphor preferably absorbs the primary light emitted by the LED and converts it into secondary light. At this time, white light with various color temperatures can be obtained by preparing some fluorescent materials that exhibit various emission colors in the visible light range and combining them arbitrarily.

It is desirable to use an LED whose emission peak wavelength is in the range from ultraviolet rays to violet light, and specifically, it is preferable to set it in the range of 350 to 420 nm. When an LED having an emission peak wavelength of more than 420 nm is used, the emission of the LED shows sharp emission at a specific wavelength in the visible light region, and therefore the balance with the emission of a fluorescent substance having a broad spectrum shape is generally poor. Therefore, it becomes difficult to satisfy the relation of the above formula (2) or (3). In addition, if the LED emits blue light, blue light will be excessively included, which is not preferable in terms of effects on the human body.

An LED that emits light in the ultraviolet or violet region has a low luminosity factor, so that the influence on white light can be reduced. It is also possible to eliminate the ultraviolet light by cutting the primary light so that the primary light (ultraviolet or violet emission) from the LED is not emitted from the white light source system. There are no particular restrictions on the type of LED other than the emission peak wavelength, and it may be a laser emitting LED or any LED material.

In order for the emission spectrum of the white light source to satisfy the relationship of the above formula (2) or (3), the phosphor to be combined with the LED is selected from among blue phosphor, green phosphor, yellow phosphor and red phosphor. It is preferable to use one or more, preferably four or more. White light emission having an arbitrary color temperature can be obtained by arbitrarily mixing these phosphors according to the spectrum of the corresponding black body radiation. As a specific mixing ratio, the blue light emitting phosphor is 45 parts by weight or more and 75 parts by weight or less, the green light emitting phosphor is 3 parts by weight or more and 7 parts by weight or less, and the yellow light emitting phosphor is 9 parts by weight or more and 17 parts by weight or less, By mixing the red phosphor in a proportion of 9 parts by weight or more and 18 parts by weight or less and adjusting the total amount of the phosphor to be 100 parts by weight, a white-emitting mixed phosphor can be obtained. The specific type of phosphor used is not particularly limited as long as the emission peak is in the range of 420 to 700 nm, but the following materials are preferable as the phosphor excited at 350 to 420 nm.

Examples of the blue phosphor include a europium-activated alkaline earth phosphate phosphor (M ₁₀ (PO ₄ ) ₆ Cl ₂ :Eu having an emission peak wavelength of 440 to 455 nm, where M is Sr, Ba, Ca, At least one element of Mg), a europium-activated magnesium aluminate phosphor having an emission peak wavelength of 450 to 460 nm (NMgAl ₁₀ O ₁₇ :Eu, where N is at least one element of Sr or Ba), The europium-activated alkaline earth aluminate blue phosphor having a peak wavelength of 450 nm and the europium-activated aluminate blue phosphor having a peak wavelength of 452 nm are included.

Examples of the green phosphor include europium having an emission peak wavelength of 520 to 550 nm, a manganese-activated orthosilicate phosphor ((Sr,Ba,Mg) ₂ SiO ₄ :Eu,Mn), and an emission peak wavelength of 535 to 535 nm. europium-activated β-sialon phosphor is _{545nm (Si 6-Z Al Z} O Z N 8-Z: a Eu e.g. _{Si 4 Al 2 O 2 N 6} : Eu), europium emission peak wavelength of 520~540nm Activated strontium sialon phosphor (Sr _3-X Eu _X Si ₁₃ Al ₃ O ₂ N ₂₁ , where x is 0.03 to 0.30, and particularly preferably x=0.2), peak wavelength is 530 nm The europium-activated orthosilicate green phosphor, the europium-manganese co-activated alkaline earth magnesium silicate green phosphor, and the like are included.

Examples of the yellow phosphor include europium and manganese-activated orthosilicate phosphor ((Sr,Ba,Mg) ₂ SiO ₄ :Eu,Mn) having an emission peak wavelength of 550 to 580 nm and an emission peak wavelength of 550 to 580 nm. cerium activated rare-earth aluminum garnet phosphor is _{(Y 3 Al 5 O 12:} Ce), cerium-activated rare earth magnesium silicon-containing garnet phosphor emission peak wavelength of _{550~580nm (Y 3 (Al, (} Mg, Si )) ₅ O ₁₂ :Ce), a cerium-activated strontium sialon phosphor (Sr _2−X Ce _X Si ₇ Al ₃ ON ₁₃ ) having an emission peak wavelength of 550 to 580 nm, where x is 0.04 to 0.10. And x=0.05 is particularly desirable.), and a europium-activated orthosilicate yellow phosphor having a peak wavelength of 555 nm, a europium-manganese co-activated alkaline earth magnesium silicate yellow phosphor, and the like are included.

Examples of the red phosphor, europium-activated strontium SiAlON phosphor emission peak wavelength of _{600~630nm (Sr 2-X Eu X} Si 7 Al 3 ON 13, a wherein X0.02～0.10, In particular, x=0.05 is preferable.), europium-activated calcium nitridoaluminosilicate phosphor (CaAlSiN ₃ :Eu) having an emission peak wavelength of 620 to 660 nm, and europium-activated alkali having an emission peak wavelength of 620 to 660 nm. An earth nitridoaluminosilicate phosphor (MAlSiN ₃ :Eu, where M is at least one element selected from the group consisting of Ca, Sr, and Ba) is included.

The phosphor is preferably mixed with a resin material and used in the form of a phosphor film. By directly or indirectly covering the periphery of the LED chip with a fluorescent film, the primary light emitted from the LED is converted into secondary light (white light) by the fluorescent film and radiated to the outside of the light source. Become. The resin material to be used is not particularly limited as long as it is a transparent material, but when an LED that emits light in the ultraviolet or violet region is used as the LED, a silicone resin or the like that has good resistance to deterioration by ultraviolet rays. Is preferred.

The white light source used in the system of the present invention preferably obtains white light emission by a combination of phosphor light emission. In the primary light from the LED, it is desirable that as much energy as possible be absorbed by the phosphor, and at the same time, it is necessary to prevent the LED light from leaking out of the light source. In particular, when the LED light contains ultraviolet rays, it may damage the skin and eyes of the human body, and it is desirable to exclude them as much as possible.

The LED module used in the system of the present invention may include an LED element and a fluorescent film covering the light emitting surface of the LED element. In order to prevent leakage of ultraviolet rays when an LED element that emits ultraviolet light or violet light is used, it is desirable to form the fluorescent film to a sufficiently thick film. By increasing the thickness of the fluorescent film, it is possible to prevent the LED light reflected on the surface of each phosphor particle from passing through the fluorescent film and leaking to the outside of the light source. At this time, if the thickness of the fluorescent film is excessively large, the light emission itself of the fluorescent material cannot go out of the fluorescent film, and the emission intensity of the fluorescent film decreases. It is generally known that the particle size of the phosphor and the optimum film thickness are in a proportional relationship. For the fluorescent film, it is desirable to use a fluorescent substance having a particle size as large as practically possible and to make the fluorescent film as thick as possible. For this purpose, the phosphor used in the LED module is preferably particles having an average particle size of 10 μm or more and 40 μm or less. The thickness of the phosphor film containing the phosphor particles having the average particle diameter is preferably 100 μm or more and 1000 μm or less. In this way, it is possible to obtain an LED module in which the light emission of the fluorescent film is not reduced as much as possible and the leakage of ultraviolet rays is suppressed as much as possible. As a result, artificial sunlight that is less affected by ultraviolet rays can be obtained.

Further, in order to further prevent the leakage of ultraviolet rays, an ultraviolet absorbing film may be formed outside the fluorescent film. In this case, a fine particle white pigment such as zinc oxide, titanium oxide or aluminum oxide can be used as the ultraviolet absorbing/reflecting material. Similar to the case of the fluorescent film, these fine particle pigments are dispersed in a resin, and by using this, an ultraviolet absorbing film is formed directly or indirectly on the outside of the fluorescent film to obtain the target LED module. You can In the LED module thus obtained, it is possible to reduce the amount of ultraviolet rays leaked to the outside of the module to 0.4 mW/lm or less.

The numerical value of the amount of ultraviolet rays can be obtained by the following method. Let P(λ) be the emission spectrum of white light emitted from the white light source and V(λ) be the spectrum of the spectral luminous efficiency, and multiply both to obtain φ.
The primary light energy emitted from the LED is obtained by integrating the spectrum F(λ) in the range of 350 to 420 nm and obtaining UV by the following formula.
The primary light energy per luminous flux emitted from the white light source can be obtained by UV/φ.

(Emission characteristics of white light source system)
The white light source system of the present invention includes a plurality of white light sources having different color temperatures in one system. By appropriately mixing the light emitted from a plurality of white light sources having different color temperatures, white light with various color temperatures can be reproduced. At this time, the visible light emission components contained in the respective white light sources have almost the same kind and intensity as the sun rays, and the white light of the intermediate color temperature obtained by mixing a plurality of white light sources is also the solar light. It has a light emission characteristic equivalent to that of light. Therefore, all white light obtained by the white light source system of the present invention is white light that satisfies the above-mentioned relational expression (2), preferably (3).

On the other hand, the color temperature of white light obtained by mixing the light emitted from a plurality of white light sources can be obtained as shown in FIG. 7. For example, white light emission is shown at two points with a color temperature on the blackbody locus of 6500K (point A in the figure) and 2000K (point B in the figure) and an intermediate color temperature between them (point C or D in the figure). A white light source system consisting of three white light sources is constructed. At this time, if only two types of white light sources are used, for example, if 6500K white light and 2000K white light are used, and if both are mixed at an arbitrary ratio, then on the straight line connecting points A and B in the figure Only white light of any color temperature can be obtained. Therefore, as can be seen from the straight line AB in the figure, the color temperature of the obtained white light has a large deviation from the black body locus and may exceed -0.01 duv. For example, at a color temperature of 3200K, the deviation is -0.013 duv, which exceeds -0.01 duv. In the white light source system of the present invention, in order to prevent the color temperature of the mixed white light from largely deviating from the point on the black body locus, the mixed white light is obtained by using at least three kinds of white light sources. For example, when a white light source of a white light source 4100K having an intermediate color temperature is additionally used, if this light source and a white light source having a color temperature of 2000K are mixed at an arbitrary ratio, an arbitrary white light on a straight line BC in the figure can be obtained. Therefore, the deviation from the black body radiation can be suppressed within the range of 0 and −0.005 duv. Further, when a white light source having a color temperature of, for example, 2950K is used as a white light source having an intermediate color temperature, if this light source and a white light source having a color temperature of 6500K are mixed at an arbitrary ratio, an arbitrary white color on a straight line AD in the figure is obtained. Light can be obtained and the deviation from blackbody radiation can be reduced to within the range of 0 and -0.005 duv as before. Therefore, in addition to the white light source with a color temperature of 2000K and the white light source with a color temperature of 6500K, by selecting any one white light source with a color temperature between 2950K and 4100K as the third white light source, It is possible to obtain white light having an arbitrary color temperature in which the absolute value of the deviation from the black body locus is 0.005 duv or less with white light having a temperature in the range of 2000K to 6500K.
The combination of white light sources for obtaining white light having a color temperature in the range of 2000 K to 6500 K and an absolute value of the deviation from the black body locus of 0.005 duv or less is one of the above It is not limited to the third white light source. Color temperature and deviation can be obtained by selecting and mixing two types of white light sources from the three or more types of white light sources that satisfy the relational expression shown in (2) and have different color temperatures, in order of increasing or decreasing color temperature. It is possible to obtain white light that satisfies the above range.

The number of the plurality of white light sources used in the white light source system needs to be at least three or more, but from the viewpoint of faithfully reproducing the color temperature on the locus of emission characteristics, especially black body radiation, The larger the number, the better. In particular, when the color temperature range reproduced by the white light source system is wide, for example, when white light having a color temperature of 2000K to 8000K is reproduced, it is preferable to use at least four types of white light sources. However, if the number of types of white light sources is too large, the color temperature reproduction characteristics are excellent, but there are restrictions because the control circuit for controlling the emission intensity of each white light source and the system configuration of the device are complicated. To do. In the range of color temperature reproduced by the white light source system of the present invention, it is desirable that the number of types of white light sources is 3 to 4 as the most efficient use number.

(Change in emission characteristics over time)
With the white light source system of the present invention, it is possible to reproduce the state of a day change from sunrise to sunset in a specific area on the earth for white light represented by sunlight. Then, in the white light source system of the present invention, the change of sunlight in one day can be expressed as a continuous change that is extremely natural to the human eye. In order to reproduce such a change, in the present invention, a system for controlling the light emission characteristics by actually measuring the daily change of sunlight at main points on the earth and utilizing the obtained data.

According to the results derived from visual color matching experiments by David Lewis MacAdam (Color Engineering 2nd Edition, Tokyo Denki University Press), the standard deviation of discriminative variation with respect to a specific central color can be expressed in the xy chromaticity diagram as "McAdam It has been found that it is represented by a range of shapes called "ovals" and that it is three times the standard deviation that can be identified by humans. According to this finding, when a calculation was performed by applying it to white light of 5000K, a discriminable threshold value was 330K (4850K to 5180K). Therefore, for example, with white light of 5000 K, the difference in color temperature of about 330 K or less cannot be discriminated by the human eye.

FIG. 8 is a graph showing a change in color temperature and a change in illuminance of sunlight from 6:00 am to 6:00 pm for a spring day in Tokyo located at 35 degrees north latitude. In FIG. 8, the graph indicated by reference numeral 1 indicates the change in color temperature, and the graph indicated by reference numeral 2 indicates the change in illuminance. This graph was created based on the results of actual measurement of changes in sunlight with time every 3 minutes. The measurement was performed using MP350 manufactured by UPRtek, and data was obtained in units of color temperature Kelvin (K) and illuminance lux (lx). The illuminance in the chart is expressed as an illuminance ratio (%) by performing relative comparison with a specific value as a reference. Further, since the change in color temperature of sunlight per day is approximately 200K or less in 3 minutes, the difference in color temperature between the measurement units in the present invention cannot be discriminated by human eyes. Therefore, even if the color temperature change is reproduced using this measurement data, it is not possible to recognize the moment when the color temperature of the light source changes, and accept the change in a natural manner as if it changed continuously. You can
FIG. 43 shows an example of the white light source system for medical facility illumination of the embodiment. As shown in FIG. 43, the white light source system for medical facility illumination of the embodiment includes a white light source unit 21 and a control unit 22. The white light source unit 21 includes a substrate 23, a plurality of white light sources 24 arranged on the substrate 23, and a light emitting device envelope 25 fixed to the substrate 23 so as to cover the plurality of white light sources. Each of the plurality of white light sources 24 is composed of an LED module. The LED module includes an LED chip 26 arranged on the substrate 23 and a fluorescent film 27 arranged on the substrate 23 and covering the LED chip 26. A wiring network is provided on the substrate 23, and the electrodes of the LED chips 26 are electrically connected to the wiring network of the substrate 23.
The control unit 22 includes a control unit 28, a memory unit 29, and a data input/output unit 30. The white light source 24 including an LED module is connected to an electronic circuit (not shown) of the control unit 28 by a wiring 31, and the white light source 24 emits light by a current flowing from the control unit 28 through the wiring 31. In the electronic circuit memory unit 29 of the control unit 28, daily change data of sunlight is stored for each place and each season (time). In order to obtain a desired pattern of illumination light source, the system user inputs location information such as city name or latitude/longitude and time information such as season to the data input/output unit 30, and the obtained data is controlled by the control unit. Send to 28. The control unit 28 extracts the stored data corresponding to the input data, reads the data of the color temperature and the illuminance of the sunlight where the place and the season are specified, and calculates the mixing intensity ratio of each white light source based on these data. To do. Based on the calculation result, the electronic circuit of the control unit 28 controls the current value applied to each white light source 24 to reproduce the required characteristic change of sunlight.

In the present invention, the change in the light emission characteristics of sunlight shown in FIG. 8 was reproduced by a method of combining a plurality of white light sources similar to sunlight according to the specific method shown in the examples.

(Example)
Hereinafter, the white light source system for illuminating a medical facility of the present invention will be specifically described with reference to examples.

(Example 1)
The white light source 1 used in the system of the present invention was manufactured.
A white light source was created by combining four types of phosphors of a blue phosphor, a green phosphor, a yellow phosphor, and a red phosphor and an LED. As the LED, an LED that emits purple or ultraviolet light having an emission peak at 395 nm was used. As the phosphor, a europium-activated alkaline earth phosphate blue phosphor having a peak wavelength of 445 nm, a europium-activated orthosilicate green phosphor having a peak wavelength of 530 nm, and a europium-activated orthosilicate having a peak wavelength of 555 nm. A yellow silicate phosphor and a europium-activated calcium nitridoaluminosilicate phosphor (CaAlSiN ₃ :Eu) with a peak wavelength of 650 nm were prepared. The respective phosphors were mixed in a weight ratio of blue phosphor:green phosphor:yellow phosphor:red phosphor=58:6:15:21. Powder having an average particle size of 30 to 35 μm was used for each phosphor. An LED module was prepared by applying a phosphor slurry in which phosphor particles were dispersed in a silicone resin so as to cover an LED chip mounted on a substrate. The thickness of the fluorescent film was about 780 μm.

Next, the light emission characteristics of the LED module were measured using a total luminous flux measuring instrument equipped with an integrating sphere according to JIS-C-8152. The color temperature of the white light source was 2074K, and the emission spectrum distribution was as shown in FIG. Further, using the spectral luminous intensity distribution V(λ) of FIG. 1, (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) of Example 1 is obtained. It is 10. On the other hand, the corresponding black body radiation spectrum of 2074K color temperature is as shown in FIG. 11, and similarly, when (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) is obtained, The curve of FIG. 12 was obtained. In addition, the difference spectrum of FIG. 10 and FIG. 12 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2) For xV(λmax2)), the curve shown in FIG. 13 was obtained. As can be seen from the curve of FIG. 13, the difference spectrum is distributed in the range of −0.04 to +0.10, and the relationship of the equation (2) shown in the following Expression 8 is obtained at each wavelength in the range of 350 nm to 800 nm. I found it satisfied.

A reflector, an envelope, and a lens, if necessary, were attached to the LED module, and an electronic circuit was further connected to obtain a white light source used in the system of the present invention. It was found that the luminous efficiency of the white light source was 65 lm/W and the intensity of the LED primary light leaked from the white light source was 0.12 mW/lm, and there was no problem in the intensity of the leaked ultraviolet light. The average color rendering index Ra of this white light source was 97.

(Example 2)
The white light source 2 used in the system of the present invention was manufactured.
A white light source was created by combining four types of phosphors of a blue phosphor, a green phosphor, a yellow phosphor, and a red phosphor and an LED. As the LED, an LED emitting purple or ultraviolet having an emission peak at 410 nm was used. As the phosphor, a europium-activated alkaline earth aluminate blue phosphor having a peak wavelength of 450 nm, a europium-activated orthosilicate green phosphor having a peak wavelength of 541 nm, and a europium-activated orthosilicate having a peak wavelength of 565 nm are used. A yellow silicate phosphor and a europium-activated calcium nitridoaluminosilicate phosphor (CaAlSiN ₃ :Eu) with a peak wavelength of 650 nm were prepared. The respective phosphors were mixed in a weight ratio of blue phosphor:green phosphor:yellow phosphor:red phosphor=62:3:17:18. Powder having an average particle size of 35 to 40 μm was used for each phosphor. An LED module was prepared by applying a phosphor slurry in which phosphor particles were dispersed in a silicone resin so as to cover an LED chip mounted on a substrate. The thickness of the fluorescent film was about 850 μm.

The color temperature of the obtained white light source was 3077 K, and the emission spectrum characteristics (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) were as shown in FIG. Further, regarding the black body radiation spectrum of the corresponding color temperature of 3077K, (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) was obtained, and the curve of FIG. 15 was obtained. .. Further, the difference spectrum of FIG. 14 and FIG. 15 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2) ×V(λmax2)) is as shown in FIG. As can be seen from the curve of FIG. 16, the difference spectrum is distributed in the range of −0.06 to +0.09, and satisfies the relationship of the following expression (2) of the equation 8 at each wavelength in the range of 350 nm to 800 nm. I understood it.

A reflector, a lens, an envelope, etc. were attached to the LED module, and an electronic circuit was further connected to obtain a white light source used in the system of the present invention. It was found that the luminous efficiency of the white light source was 66 lm/W and the intensity of the LED primary light leaked from the white light source was 0.09 mW/lm, and there was no problem in the intensity of the leaked ultraviolet light. The average color rendering index Ra of this white light source was 97.

(Example 3)
The white light source 3 used in the system of the present invention was manufactured.
A white light source was created by combining four types of phosphors of a blue phosphor, a green phosphor, a yellow phosphor, and a red phosphor and an LED. As the LED, an LED that emits violet or ultraviolet light having an emission peak at 420 nm was used. As the phosphor, europium-activated alkaline earth phosphate blue phosphor having a peak wavelength of 452 nm, europium-activated orthosilicate green phosphor having a peak wavelength of 530 nm, and cerium-activated rare earth having a peak wavelength of 560 nm. A magnesium silicon-containing garnet phosphor and a europium-activated strontium sialon phosphor having a peak wavelength of 629 nm were prepared. The respective phosphors were mixed in a weight ratio of blue phosphor:green phosphor:yellow phosphor:red phosphor=65:6:14:15. Powder having an average particle size of 20 to 30 μm was used for each phosphor. An LED module was prepared by applying a phosphor slurry in which phosphor particles were dispersed in a silicone resin so as to cover an LED chip mounted on a substrate. The thickness of the fluorescent film was about 705 μm.

The color temperature of the obtained white light source was 4029K, and the emission spectrum characteristics (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) were as shown in FIG. Further, regarding the black body radiation spectrum of the corresponding color temperature of 4029 K, (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) was obtained, and the curve of FIG. 18 was obtained. .. Further, the difference spectrum (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2) in FIG. 17 and FIG. ×V(λmax2)) is as shown in FIG. As can be seen from the curve in FIG. 19, the difference spectrum is distributed in the range of −0.08 to +0.05, and satisfies the relationship of the following expression (2) of the equation 8 at each wavelength in the range of 350 nm to 800 nm. I understood it.

A reflector, a lens, an envelope, etc. were attached to the LED module, and an electronic circuit was further connected to obtain a white light source used in the system of the present invention. It was found that the luminous efficiency of the white light source was 63 lm/W and the intensity of the LED primary light leaked from the white light source was 0.21 mW/lm, and there was no problem in the intensity of the leaked ultraviolet light. The average color rendering index Ra of this white light source was 98.

(Example 4)
The white light source 4 used in the system of the present invention was manufactured.
A white light source was created by combining four types of phosphors of a blue phosphor, a green phosphor, a yellow phosphor, and a red phosphor and an LED. The LED used was an LED that emits purple or ultraviolet light having an emission peak at 415 nm. As the phosphor, a europium-activated aluminate blue phosphor having a peak wavelength of 452 nm, a europium-activated β-sialon phosphor having a peak wavelength of 537 nm, and a cerium-activated rare earth aluminum garnet phosphor having a peak wavelength of 572 nm. And a europium-activated alkaline earth nitridoaluminosilicate phosphor having a peak wavelength of 640 nm was prepared. The respective phosphors were mixed in a weight ratio of blue phosphor:green phosphor:yellow phosphor:red phosphor=71:7:9:13. Powder having an average particle size of 15 to 25 μm was used for each phosphor. An LED module was prepared by applying a phosphor slurry in which phosphor particles were dispersed in a silicone resin so as to cover an LED chip mounted on a substrate. The thickness of the fluorescent film was about 660 μm.

The color temperature of the obtained white light source was 5085 K, and the emission spectrum characteristics (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) were as shown in FIG. Further, regarding the black body radiation spectrum of the corresponding color temperature of 5085K, (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) was obtained, and the curve of FIG. 21 was obtained. .. Further, the difference spectrum of FIG. 20 and FIG. 21 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2) ×V(λmax2)) is as shown in FIG. As can be seen from the curve in FIG. 22, the difference spectrum is distributed in the range of −0.10 to +0.025, and satisfies the relationship of the following expression (2) of the equation 8 at each wavelength in the range of 350 nm to 800 nm. I understood it.

A reflector, a lens, an envelope, etc. were attached to the LED module, and an electronic circuit was further connected to obtain a white light source used in the system of the present invention. It was found that the luminous efficiency of the white light source was 63 lm/W and the intensity of the LED primary light leaked from the white light source was 0.24 mW/lm, and there was no problem in the intensity of the leaked ultraviolet light. The average color rendering index Ra of this white light source was 97.

(Example 5)
The white light source 5 used in the system of the present invention was manufactured.
A white light source was created by combining four types of phosphors of a blue phosphor, a green phosphor, a yellow phosphor, and a red phosphor and an LED. As the LED, an LED that emits purple or ultraviolet light having an emission peak at 410 nm was used. As the phosphor, a europium-activated alkaline earth phosphate phosphor having a peak wavelength of 440 to 455 nm, a europium-activated strontium sialon phosphor having a peak wavelength of 525 nm, and a europium-activated strontium having a peak wavelength of 575 nm. A sialon phosphor and a europium-activated alkaline earth nitridoaluminosilicate phosphor having a peak wavelength of 640 nm were prepared. The respective phosphors were mixed in a weight ratio of blue phosphor:green phosphor:yellow phosphor:red phosphor=75:6:9:10. Powder having an average particle size of 40 to 45 μm was used for each phosphor. An LED module was prepared by applying a phosphor slurry in which phosphor particles were dispersed in a silicone resin so as to cover an LED chip mounted on a substrate. The thickness of the fluorescent film was about 850 μm.

The color temperature of the obtained white light source was 6020K, and the emission spectrum characteristics (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) were as shown in FIG. Further, regarding the black body radiation spectrum of the corresponding color temperature of 6020K, (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) was obtained, and the curve of FIG. 24 was obtained. .. Further, the difference spectrum of FIG. 23 and FIG. 24 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2) ×V(λmax2)) is as shown in FIG. As can be seen from the curve in FIG. 25, the difference spectrum is distributed in the range of −0.12 to +0.02, and satisfies the relationship of the following expression (2) of the equation 8 at each wavelength in the range of 350 nm to 800 nm. I understood it.

A reflector, a lens, an envelope, etc. were attached to the LED module, and an electronic circuit was further connected to obtain a white light source used in the system of the present invention. The luminous efficiency of the white light source was 64 lm/W, and the intensity of the LED primary light leaked from the white light source was 0.08 mW/lm, and it was found that there is no problem in the intensity of the leaked ultraviolet light. The average color rendering index Ra of this white light source was 97.

(Example 6)
The white light source 6 used in the system of the present invention was manufactured.
A white light source was created by combining three types of phosphors of a blue phosphor, a yellow phosphor, and a red phosphor and an LED. The LED used was an LED that emits purple or ultraviolet light having an emission peak at 405 nm. As the phosphor, europium-activated alkaline earth phosphate blue phosphor having a peak wavelength of 450 nm, europium-activated orthosilicate green phosphor having a peak wavelength of 560 nm, and europium-activated phosphorescence having a peak wavelength of 655 nm. An alkaline earth nitrido aluminosilicate phosphor was prepared. The respective phosphors were mixed in a weight ratio of blue phosphor:yellow phosphor:red phosphor=82:9:9. Powder having an average particle size of 30 to 35 μm was used for each phosphor. An LED module was prepared by applying a phosphor slurry in which phosphor particles were dispersed in a silicone resin so as to cover an LED chip mounted on a substrate. The thickness of the fluorescent film was about 730 μm.

The color temperature of the obtained white light source was 6785K, and the emission spectrum characteristics (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) were as shown in FIG. Further, regarding the black-body radiation spectrum of the corresponding color temperature of 6785K, (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) was obtained, and the curve of FIG. 27 was obtained. .. Further, the difference spectrum of FIG. 26 and FIG. 27 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2) ×V(λmax2)) is as shown in FIG. As can be seen from the curve in FIG. 28, the difference spectrum is distributed in the range of −0.125 to +0.015, and satisfies the relationship of the following expression (2) of the equation 8 at each wavelength in the range of 350 nm to 800 nm. I understood it.

A reflector, a lens, an envelope, etc. were attached to the LED module, and an electronic circuit was further connected to obtain a white light source used in the system of the present invention. The luminous efficiency of the white light source was 60 lm/W, and the intensity of the LED primary light leaked from the white light source was 0.14 mW/lm, and it was found that there is no problem in the intensity of the leaked ultraviolet light. The average color rendering index Ra of this white light source was 97.

(Comparative Example 1)
A white light source 7 used in the system of the comparative example was manufactured.
A white light source was created by combining a yellow phosphor and an LED. As the LED, a blue light emitting LED having an emission peak at 448 nm was used. A europium-activated orthosilicate green phosphor having a peak wavelength of 560 nm was used as the phosphor. A powder having an average particle size of 7 μm was used as the phosphor. An LED module was prepared by uniformly applying a phosphor slurry in which phosphor particles were dispersed in a silicone resin so as to cover an LED chip mounted on a substrate. The thickness of the phosphor film was about 65 μm as a result of adjusting the thickness to obtain a desired white light by mixing the blue light of the LED and the yellow light of the phosphor.

The color temperature of the obtained white light source was 6338 K, and the emission spectrum characteristics (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) were as shown in FIG. Further, regarding the black-body radiation spectrum of the corresponding color temperature of 6338K, (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) was obtained, and the curve of FIG. 30 was obtained. .. Further, the difference spectrum of FIG. 33 and FIG. 34 (P(λ)×V(λ))/(P(λmax1)×V(λmax1))−(B(λ)×V(λ))/(B(λmax2) ×V(λmax2)) is as shown in FIG. As can be seen from the curve of FIG. 31, the difference spectrum is distributed within the range of −0.32 to +0.02, and the relationship of the equation (2) of the above-mentioned expression 8 cannot be satisfied, and the difference of 0. It was found to show a large value of 34.

A reflector, a lens, an envelope, etc. were attached to the LED module, and an electronic circuit was further connected to obtain a white light source of a comparative example. The emission efficiency of the white light source was 71 lm/W, which showed high efficiency emission, but the average color rendering index Ra was 70, which was an extremely low value. As described above, the white light source used in the system of the comparative example apparently emitted white light similar to that of the present invention, but exhibited poor redness and poor color rendering properties. When such a light source is used for illumination of, for example, a patient's room, the patient's complexion looks pale, which not only adversely affects the psychological side, but also causes a strong blue light emitted from the LED to cause a blue hazard, etc. The obstacles were also worrisome.

(Example 7)
The white light source system 1 for medical facility illumination of the present invention was manufactured by using three kinds of light sources of the white light sources 1, 3, and 6. A control circuit and a power supply are connected to each white light source, the current value flowing in each white light source is adjusted to an arbitrary value, the white light emitted by each white light source is mixed at an arbitrary ratio, and various values from 2074K to 6785K are mixed. A white light source system that can obtain white light with a color temperature of The color temperature of the obtained white light is on two straight lines connected at three points of 2074K (P ₁ ), 4029K (P ₂ ) and 6785K (P ₃ ) on the black body locus shown in FIG. Indicated by dots. The color temperature of white light emitted from the white light source system 1 was changed in the range of 6785K to 4029K by mixing the white light source having a color temperature of 6785K and the white light source having a color temperature of 4029K at an arbitrary ratio. Further, by mixing the white light source having the color temperature of 4029K and the white light source having the color temperature of 2074K at an arbitrary ratio, the color temperature of the white light emitted from the white light source system 1 is changed in the range of 4029K to 2074K. It was Thus, two white light sources were selected so that the difference in color temperature was small, and these were mixed at an arbitrary ratio, whereby white light was emitted from the white light source system 1. As a result, as is clear from FIG. 32, in the color temperature of the white light source obtained by the white light source system 1, the deviation from the black body locus was 0.005 duv or less in the range from 2074K to 6785K. The average color rendering index of the white light source obtained by this system was 97.

(Example 8)
The white light source system 2 for medical facility illumination of the present invention was manufactured using four types of white light sources 1, 2, 4, and 6. A control circuit and a power supply are connected to each white light source, the current value flowing in each white light source is adjusted to an arbitrary value, the white light emitted by each white light source is mixed at an arbitrary ratio, and various values from 2074K to 6785K are mixed. A white light source system that can obtain white light with a color temperature of The color temperatures of the obtained white light are 2074K (P ₄ ), 3077K (P ₅ ), 4029K (P ₆ ), 5085K (P ₇ ) and 6785K (P ₈ ) on the black body locus shown in FIG. It is indicated by points on four straight lines connected by five points. The color temperature of white light emitted from the white light source system 1 was changed in the range of 6785K to 5085K by mixing the white light source having a color temperature of 6785K and the white light source having a color temperature of 5085K at an arbitrary ratio. Further, by mixing the white light source having a color temperature of 5085K and the white light source having a color temperature of 4029K at an arbitrary ratio, the color temperature of the white light emitted from the white light source system 1 is changed in the range of 5085K to 4029K. It was By mixing the white light source having a color temperature of 4029K and the white light source having a color temperature of 3077K at an arbitrary ratio, the color temperature of the white light emitted from the white light source system 1 was changed in the range of 4029K to 3077K. The color temperature of the white light emitted from the white light source system 1 was changed in the range of 3077K to 2074K by mixing the white light source having the color temperature of 3077K and the white light source having the color temperature of 2074K at an arbitrary ratio. Thus, two white light sources were selected so that the difference in color temperature was small, and these were mixed at an arbitrary ratio, whereby white light was emitted from the white light source system 1. As a result, as is clear from FIG. 33, in the color temperature of the white light source obtained by the white light source system 1, the deviation from the black body locus showed a value of 0.0025 duv or less in the range of 2074K to 6785K. The average color rendering index of the white light source obtained by this system was 97.

(Example 9)
Using the white light source system 1, the sunset was reproduced from the sunrise in autumn Naha, Okinawa. FIG. 34 is a diagram showing changes in the color temperature and illuminance of sunlight from about 6:30 in the morning to about 6:30 in the evening. Curve 3 in FIG. 34 is a curve showing a change in color temperature, and curve 4 is a curve showing a change in illuminance. It became brighter with the sunrise, the illuminance became highest around 12:00, and after that the illuminance continued to be high until around 14:00, after which the illuminance gradually decreased toward the setting sun. Regarding the color temperature, the bright red sun of 2000K appeared at sunrise, the color temperature increased with the increase of illuminance, and it changed from warm white to white and neutral white, reaching the highest level around 14:00. It became a daylight color of 6500K. After that, the course opposite to that in the morning was followed, and it returned to 2000K around 18:30, and the sunset came.

In the white light source system for illuminating a medical facility of the present invention, the temporal changes in color temperature and illuminance shown in FIG. 34 are reproduced by controlling the current value applied to the white light source. First, in order to obtain white light of a specific color temperature, the ratio of currents applied to a plurality of white light sources was determined. Next, in order to deal with the change in illuminance, the intensity of the total current was adjusted so that a predetermined illuminance was obtained while maintaining the above current ratio. In the white light source system for illuminating a medical facility of the present invention, program control of the current value is performed so that the data of the change over time shown in FIG. Reproduced the change.

Such a white light source system was used as room lighting for inpatients in a hospital. The lighting does not reproduce the instantaneous characteristics of sunlight, but reproduces the light emitting characteristics that change from moment to moment, which is expected to have a positive effect on the human body clock and the like. Furthermore, the characteristic change due to white illumination reproduces a gentle change that cannot be discerned by human eyes, and therefore is perceived by humans as an extremely natural change similar to sunlight. Therefore, even in a physically inferior hospital patient, etc., it can be accepted as a reasonably gentle lighting.

(Example 10)
The white light source system 2 was used to reproduce the sunset from the sunrise in Los Angeles, USA in the summer. FIG. 35 shows changes in color temperature and illuminance of sunlight over time from about 4:30 in the morning to about 6:30 in the evening. A curve 5 in FIG. 35 is a curve showing a change in color temperature, and a curve 6 is a curve showing a change in illuminance. The highest color temperature was 6600K from about 11:00 to about 12:00. Further, the time when the illuminance was highest was also between 11:00 and 12:00, similar to the color temperature. Among the seasons, the illuminance was the highest in summer, and compared to the winter season, which had the lowest illuminance in the same Los Angeles, the illuminance ratio was 175%, showing a large difference.

In the white light source system for illuminating a medical facility of the present invention, the time-dependent changes in color temperature and illuminance shown in FIG. 35 are reproduced by controlling the current value applied to the white light source based on the measured value every 3 minutes. did. Then, this white light source system was adopted as general lighting in the home. Lighting does not reproduce the instantaneous characteristics of sunlight, but reproduces the luminescence characteristics that change from moment to moment in a natural form, creating artificial sunlight even in a room where sunlight does not enter. did it. Such an illumination not only has a good effect on the health of the human body, but also exhibits excellent characteristics when used for general purposes as an ultra-high color rendering illumination having an average color rendering index Ra of 97.

(Comparative example 2)
Using the white light source 1 of the example and the white light source 7 of the comparative example, the white light source system 3 of the comparative example was manufactured. A control circuit and a power supply are connected to each white light source, the current value flowing in each white light source is adjusted to an arbitrary value, the white light emitted by each white light source is mixed at an arbitrary ratio, and various values from 2074K to 6338K A white light source system that can obtain white light with a color temperature of The color temperature of the obtained white light is indicated by a point on a straight line connected by two points of 2074K (P ₉ ) and 6338K (P ₁₀ ) on the black body locus shown in FIG. 36. Therefore, from FIG. 36, the color temperature of the white light source obtained by the white light source system 3 is limited to two points of 2074K and 6338K, and white light of the color temperature on the black body locus is obtained, but at the intermediate color temperature other than the two. , Only white light with a large deviation from the black body locus could be obtained. Especially, in the vicinity of 3500K, there was a large deviation exceeding 0.01 duv.

With the illumination using the white light source system 3 of the comparative example, not only the color temperature on the black body locus cannot be accurately reproduced, but also there is a shape difference with the emission spectrum of the black body radiation of each color temperature. It was not possible to obtain a white light with a natural color. With respect to 2074K, the reproduction level of sunlight was similar to that of the light source of the embodiment of the present invention, but the deviation increased as the color temperature increased, and at 6338K, only unnatural white light with a strong blue component was shown. .. Also, with this system, white light with various color temperatures can be obtained, but since it is necessary to adjust the color tone each time, white light with the same color temperature continues for a long time, and the color temperature increases with each switch. Because of the changing unnatural changes, we were only able to obtain lighting that was significantly different from the natural changes in sunlight.

(Examples 11 to 16)
By selecting a pattern by a seasonal unit or a difference in latitude or longitude from a plurality of change patterns including a change pattern different for each time period and a change pattern for each place, in each example, various points and Reproduced seasonal sunlight.
Example 11: Spring Wakkanai, Hokkaido, time 5:30 to 17:30, color temperature 2000K to 6500K,
Example 12: Summer of Taipei, Taiwan, time 5:30 time to 19: 30 time, color temperature 2000 K~6600K
Example 13: Wakkanai, Hokkaido in summer, time from 4:00 to 18:00, color temperature 2000K to 6600K
Example 14: Naha City, Okinawa, winter, time from 6:30 to 18:30, color temperature from 2000K to 6500K
Example 15: Tokyo, Japan in winter, time around 5:30 to 17:30, color temperature 2000K to 6500K
Example 16: Wakkanai, Hokkaido in winter, time 5:30 to 17:30, color temperature 2000 to 6500K
The respective color temperature changes and illuminance changes are as shown in FIGS. 37 to 42, curves showing changes in color temperature are shown by 7, 9, 11, 13, 15, and 17. Also, curves showing changes in illuminance are shown by 8, 10, 12, 14, 16, and 18. In the white light source system of the present invention, the changes over time in the color temperature and the illuminance shown in FIGS. 37 to 42 were reproduced by controlling the current value applied to the white light source based on the measured value every 3 minutes. By using such a light source as lighting for hospitals, offices, and general households, it can be used for various purposes such as medical assistance, health promotion, and high color rendering lighting that creates a comfortable space. .
Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and modifications thereof are included in the scope and the gist of the invention, and are also included in the invention described in the claims and the scope equivalent thereto.
The inventions described in the initial claims of the present application will be additionally described below.
[1] A white light source system for medical facility lighting, comprising a plurality of white light sources,
The emission spectrum of each white light source is P(λ), the emission spectrum of black body radiation showing the same color temperature as each white light source is B(λ), and the spectral luminous efficiency spectrum is V(λ), P(λ). Assuming that the wavelength that maximizes ×V(λ) is λmax1 and the wavelength that maximizes B(λ)×V(λ) is λmax2, (P(λ)×V(λ))/(P(λmax1) The absolute value of the difference between (×V(λmax1)) and (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) satisfies the relational expression shown in Equation 1 above, A white light source system for illuminating a medical facility, characterized in that the emission characteristics of white light emitted from the system are continuously changed by changing the mixing ratio of light from the white light source.
[2] In the white light source system for medical facility illumination according to [1], the change over time in the emission characteristics of the white light is selected from a plurality of change patterns based on the results of actual measurement of changes in sunlight for one day. A white light source system for medical facility lighting, which is characterized by the following.
[3] In the white light source system for medical facility illumination according to [2], the plurality of change patterns include a change pattern that is different for each time period and a change pattern that is different for each place. A white light source system for medical facility lighting, which can select a pattern depending on the latitude or longitude.
[4] In the white light source system for illuminating a medical facility according to any one of [1] to [3], the plurality of white light sources are three or more types of white having different color temperatures that satisfy the relational expression shown in Formula 1. The white light emitted from the system is 2000K on a black body locus by being composed of a light source, and by selecting and mixing two kinds of white light sources from the three or more kinds of white light sources in order of increasing or decreasing color temperature. A white light source system for illuminating a medical facility, wherein the white light has a color temperature of 6500 K or less and a deviation from the color temperature of ±0.005 duv or less.
[5] The white light source system for medical facility illumination according to [4], wherein the plurality of white light sources are three types of white light sources having different color temperatures.
[6] In the white light source system for medical facility illumination according to [5], among the three types of white light sources, the white light source having the highest color temperature is 6500K or less, and the white light source having the lowest color temperature is 2000K or more. The white light source system for illuminating a medical facility is characterized in that a white light source having an intermediate color temperature between them is in a range of 2950K or more and 4050K or less.
[7] In the white light source system for medical facility illumination according to any one of [1] to [6], each of the plurality of white light sources includes a light emitting diode and a phosphor, and the light emitting diode has a peak wavelength of 350 nm. White for medical facility illumination, which emits ultraviolet or violet primary light having a wavelength of up to 420 nm, and the phosphor absorbs the primary light from the light emitting diode and converts it into white secondary light. Light source system.
[8] In the white light source system for medical facility illumination according to [7], the phosphor is three or more kinds selected from the group consisting of a blue light emitting phosphor, a green light emitting phosphor, a yellow light emitting phosphor and a red phosphor. A white light source system for illuminating a medical facility, characterized by being mixed with the above phosphors.
[9] In the white light source system for medical facility illumination according to [8], the phosphor includes a blue light emitting phosphor of 45 parts by weight or more and 75 parts by weight or less, a green light emitting phosphor of 3 parts by weight or more and 7 parts by weight or less, The yellow light emitting phosphor is mixed in a ratio of 9 parts by weight or more and 17 parts by weight or less, and the red phosphor is mixed in a ratio of 9 parts by weight or more and 18 parts by weight or less, and the total amount of the phosphors is adjusted to 100 parts by weight. White light source system for medical facility lighting.
[10] In the white light source system for medical facility illumination according to any one of [8] to [9], the blue light emitting phosphor is a europium-activated alkaline earth phosphate phosphor, and the green light emitting phosphor is europium. , Manganese co-activated alkaline earth magnesium silicate phosphor, the yellow light-emitting phosphor is europium, manganese co-activated alkaline earth magnesium silicate phosphor, and the red phosphor is europium-activated calcium nitrido aluminosilicate phosphor White light source system for medical facility lighting, which is a body.

1... Curve showing change in color temperature, 2... Curve showing change in illuminance, 3... Curve showing change in color temperature, 4... Curve showing change in illuminance, 5... Curve showing change in color temperature, 6... Curve showing change of illuminance, 7 curve showing change of color temperature, 8 curve showing change of illuminance, 9 curve showing change of color temperature, 10 curve showing change of illuminance, 11 curve of color temperature Curve showing change, 12... Curve showing change of illuminance, 13... Curve showing change of color temperature, 14... Curve showing change of illuminance, 15... Curve showing change of color temperature, 16... Showing change of illuminance Curves, 17... Curves showing changes in color temperature, 18... Curves showing changes in illuminance, 21... White light source section, 22... Control section, 23... Substrate, 24... Plural white light sources, 25... Light emitting device envelope , 26... LED chip, 27... Fluorescent film, 28... Control section, 29... Memory section, 30... Data input/output section.

Claims (9)

A white light source system for medical facility lighting, comprising a plurality of white light sources having different color temperatures,
The emission spectrum of each white light source is P(λ), the emission spectrum of black body radiation showing the same color temperature as each white light source is B(λ), and the spectral luminous efficiency spectrum is V(λ), P(λ). When the wavelength at which xV(λ) is maximum is λmax1 and the wavelength at which B(λ)×V(λ) is maximum is λmax2,
The difference between (P(λ)×V(λ))/(P(λmax1)×V(λmax1)) and (B(λ)×V(λ))/(B(λmax2)×V(λmax2)) When changing the color temperature of the white light emitted from the white light source system by changing the mixing ratio of the light from the plurality of white light sources, the absolute value satisfies the relational expression shown in the following Expression 1, By making the difference in color temperature of the white light before and after the change fall within the range defined by the McAdam ellipse, the emission characteristics of the white light emitted from the system are continuously changed with the passage of time. A medical facility illumination characterized in that, along with the change, the temporal change of the emission characteristics of the white light proceeds according to a pattern selected from a plurality of change patterns based on the result of actual measurement from sunrise to sunset of sunlight. White light source system.
The white light source system for illuminating a medical facility according to claim 1 , wherein the plurality of change patterns include a different change pattern for each time period and a different change pattern for each place, and the plurality of change patterns include a seasonal unit, a latitude or a longitude. A white light source system for lighting medical facilities, which is characterized in that the pattern can be selected depending on the difference. The white light source system for medical facility illumination according to any one of claims 1 and 2 , wherein the plurality of white light sources are three or more types of white light sources having different color temperatures that satisfy the relational expression shown in the mathematical expression 1. The white light emitted from the system is 2000K or more on a black body locus by selecting and mixing two kinds of white light sources from the three or more kinds of white light sources in order of increasing or decreasing color temperature. A white light source system for illuminating a medical facility, which is a white light having a color temperature of 6500K or less and a deviation from the color temperature within ±0.005 duv. The white light source system for medical facility illumination according to claim 3 , wherein the plurality of white light sources are three types of white light sources having different color temperatures. The white light source system for medical facility illumination according to claim 4 , wherein among the three types of white light sources, the white light source having the highest color temperature is 6500K or less, and the white light source having the lowest color temperature is 2000K or more. A white light source system for illuminating a medical facility, characterized in that the white light source having an intermediate color temperature is in a range of 2950K or higher and 4050K or lower. The white light source system for medical facility illumination according to any one of claims 1 to 5 , wherein each of the plurality of white light sources includes a light emitting diode and a phosphor, and the light emitting diode has a peak wavelength of 350 nm to. A white light source for medical facility illumination, which emits ultraviolet or violet primary light of 420 nm, and the phosphor absorbs the primary light from the light emitting diode and converts the primary light into white secondary light. system. The white light source system for medical facility illumination according to claim 6 , wherein the phosphors are three or more kinds of phosphors selected from the group consisting of blue light emitting phosphors, green light emitting phosphors, yellow light emitting phosphors, and red phosphors. A white light source system for medical facility lighting, which is a mixture of The white light source system for illuminating a medical facility according to claim 7 , wherein the phosphors are 45 parts by weight or more and 75 parts by weight or less of blue emitting phosphor, 3 parts by weight or more and 7 parts by weight or less of green emitting phosphor, and yellow emitting fluorescence. A medical facility characterized in that the body is mixed in a ratio of 9 parts by weight to 17 parts by weight and the red phosphor is mixed in a ratio of 9 parts by weight to 18 parts by weight, and the total amount of the phosphor is adjusted to 100 parts by weight. White light source system for lighting. The white light source system for medical facility illumination according to any one of claims 7 to 8 , wherein the blue light emitting phosphor is a europium-activated alkaline earth phosphate phosphor, and the green light emitting phosphor is a europium-manganese compound. Activated alkaline earth magnesium silicate phosphor, the yellow light emitting phosphor is europium, manganese co-activated alkaline earth magnesium silicate phosphor, and the red phosphor is europium activated calcium nitridoaluminosilicate phosphor A white light source system for medical facility lighting.