JP2007157990A - Light emitting diode lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting diode lighting system capable of preventing color deterioration of a target of lighting such as a picture, and obtaining required color rendering properties. <P>SOLUTION: The light emitting diode lighting system includes a light emitting diode device having a light emitting diode, and a wavelength converter for converting light emission from the diode into required colored light for emitting white light from the required colored light and the light emitted from the diode; and has respective light emission wavelength regions including, at least, 400-500 nm, 500-600 nm and 600-700 nm. Where λl, λn and λh refer to the light emission wavelength regions respectively, radiant intensity is specified such that the radiant intensity of λl is 0-2 W/m<SP>2</SP>, the radiant intensity of λn is approximately twice that of λl, and the radiant intensity of λh is specified to acquire an average color rendering index of 70 or more. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light emitting diode illumination device.

  Conventionally, as an example of a lighting device for a museum or an art museum, a fluorescent lamp for an art museum or a museum (hereinafter referred to as an NU fluorescent lamp) for the purpose of preventing fading of a picture or the like is known.

  This NU fluorescent lamp has a spectral distribution substantially the same as that of a halogen bulb, and cuts ultraviolet rays that have a great influence on fading.

The fading suppression effect of this NU fluorescent lamp is determined by the CIE (International Commission on Illumination) when the lighting method shown in JIS / Z9110 is used to illuminate the first and second blue scales that can detect the degree of fading at about 500 lx. At the proposed annual exposure limit of 15,000 lx · hr, it has been clarified that the degree of fading (ΔE, CIE 1964 color system) can be reduced more than conventional fluorescent lamps (for example, white, three-wavelength type, D65). (For example, refer nonpatent literature 1).
The Illuminating Engineering Journal Vol. 74, No. 4 (Heisei 2) P212-216

  By the way, in recent years, illuminations for museums / museums are mainly used in combination with a wall washer illumination device using a fluorescent lamp, and a combination of spot illumination using halogen, low-voltage halogen, or the like. For example, a limited space such as a showcase is illuminated by a combination of a fluorescent lamp and a halogen lamp.

  However, such a combination lighting device can easily exceed 500 lx, and the annual exposure amount is inevitably high. For this reason, it was supposed to accelerate fading. Therefore, as a countermeasure, in most showcase lighting, a fluorescent lamp is removed and illumination is performed only with a halogen lamp. However, since this can only illuminate only the object with a spot light source, an illuminating device for illuminating the entire space in place of the fluorescent lamp is required. At the same time, the required color rendering properties are also required.

  On the other hand, a white light emitting diode (LED) illumination device is a light source that does not include ultraviolet and infrared radiation, and is therefore an illumination device that has conditions for illumination for museums and museums. In particular, low power, small size, light weight, easy controllability of light, and various light colors are used as lighting for cultural assets such as paintings, sculptures, and crafts made of organic and inorganic composite materials. There are enough, and it is possible to install it as lighting for museums in the future. However, at present, the white light emitting diode illumination device is not yet used as a museum illumination device.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a light-emitting diode illuminating device that can suppress discoloration of an object to be illuminated such as a painting and obtain a required color rendering property. .

The invention according to claim 1 includes a light emitting diode device that includes a light emitting diode and a wavelength converter that converts light emitted from the light emitting diode into required color light, and emits white light from the required color light and the light emitted from the light emitting diode. The emission intensity range of λl is 0 to ² W / m ² when the emission wavelength ranges are λ1, λn, and λh, respectively, at least 400 to 500 nm, 500 to 600 nm, and 600 to 700 nm. The light emitting diode illuminating device is characterized in that the radiation intensity of λh is set so that the radiation intensity of λn is almost twice that of λl and the average color rendering index is 70 or more.

  Here, the fact that the radiant intensity of λn is approximately twice the λl means that it includes a range of ± 10% of the doubled radiant intensity.

  2. The light emitting diode according to claim 1, wherein the radiant intensity of λh is equal to or higher than the radiant intensity of λn, and the average color rendering index is 80 or higher. It is a lighting device.

  According to the first aspect of the present invention, the radiation intensity in the light emission wavelength region λn of 400 to 500 nm that affects the fading of an illumination object such as a painting is almost half of the radiation intensity in the light emission wavelength region λn of 500 to 600 nm. The fading suppression effect of the illumination target can be achieved.

  In addition, since the radiation intensity in the emission wavelength region λh of 600 to 700 nm that affects the improvement in color rendering is set to an average color rendering index of 70 or more, an average color rendering index of 70 or more can be achieved.

  Further, according to the invention of claim 2, since the radiation intensity in the emission wavelength region λh is configured to be an average color rendering index of 80 or more, an average color rendering index of 80 or more can be achieved.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same or corresponding parts are denoted by the same reference numerals.

  FIG. 1 is a table showing, for example, the emission intensity (W) for each of a plurality of wavelength ranges of five types of light emitting diode illuminating devices A to E that emit white light, and FIG. FIGS. 3A to 3E are diagrams showing electrical output characteristics, color temperature (K), and average color rendering index (Ra) in a list, and FIGS. 3A to 3E are spectral distribution diagrams of these light-emitting diode illuminators A to E. FIG.

  1-3, the light-emitting diode illuminating device D is a light-emitting diode illuminating device according to an embodiment of the present invention. That is, the light-emitting diode illuminating device D has at least emission wavelength ranges of 400 to 500 nm (λl), 500 to 600 nm (λn), and 600 to 700 nm (λh), respectively, among the visible light emission wavelength ranges of 380 to 780. The emission intensity in the emission wavelength region λl of 400 to 500 nm is 0.44 W, for example.

  The emission intensity in the emission wavelength region λn of 500 to 600 nm is 0.91 W, which is almost twice the emission intensity in the emission wavelength region λl. That is, it is within the range (0.792 to 0.968 W) of ± 10% (± 0.088 W) which is twice (0.88 W) of the radiation intensity of 0.44 W of 400 to 500 nm (λl).

  Further, the radiation intensity in the emission wavelength region λh of 600 to 700 nm is 0.93 W. For this reason, the average color rendering index (Ra) of the light-emitting diode illuminating device D is 75 as shown in FIG.

  This light-emitting diode illuminating device D has been verified to be superior in terms of fading suppression effect and color rendering by a verification experiment for verifying the effectiveness or suitability of white light-emitting light-emitting diode illuminating devices as illumination for museums and museums. It is a thing. Hereinafter, this verification experiment will be described.

(Light-emitting diode lighting device)
This verification experiment was conducted on five types of light emitting diode illuminators A to E that emit white light. The light-emitting diode illuminating devices A to E are provided with a plurality of light-emitting diode devices arranged in a matrix of 9 columns and 18 rows (9 × 18), for example, on the light source arrangement surface of the fixture body. There is provided a lighting device for supplying a direct current to the diode device to light it.

  These light emitting diode devices A to D can obtain white light by a combination of blue light emitting diodes emitting blue light and light emission of yellow phosphors excited thereby. The light emitting diode illumination device A has the highest color temperature (for example, 7716K), and the light emitting diode illumination device D has the lowest color temperature (for example, 2869K). The light-emitting diode illuminating device E obtains white light by combining an ultraviolet light-emitting diode that emits ultraviolet light and emission of red (R), green (G), and blue (B) phosphors excited thereby. Can do. The electrical characteristics and the like of these white light emitting diode illumination devices A to E are as shown in FIG. 2, and the power consumption is about 40 W, the total luminous flux is about 700 to 900 lm, the light emission efficiency is about 20 lm / W, and the average color rendering index Ra Is 76-87.

  3A to 3E are spectral distribution diagrams of the light emitting diode illuminating devices A to E, and the spectral distributions of the light emitting diode illuminating devices A to E are different from each other. The reason for this is that for the light emitting diode illumination devices A to D, the same blue light emitting diodes are used, but the composition of the yellow phosphors is different. This is because the amount of absorption of the yellow phosphor to be absorbed is different. For this reason, the intensities (au) of the blue regions are different.

  Further, as described above, the light-emitting diode illuminating device E is configured to obtain white light by a combination of ultraviolet light-emitting diodes and light emission of red (R), green (G), and blue (B) phosphors. Since the light emission colors of the light emitting diodes are different from the configurations of the light emitting diode illumination devices A to D, the spectral distribution is also greatly different from these.

(Verification experiment)
The verification experiment of these light emitting diode illumination devices A to E was performed using the exposure device 1 shown in FIG.

  This exposure apparatus 1 is provided with an openable / closable door 3 at the front opening end of a square cylindrical case body 2 having a front opening.

  The case body 2 is, for example, a square cylinder having an internal size of 50 cm in width, 51.5 cm in depth, and 65 cm in height, and the material is made of black polypropylene with less reflection like the open / close door 3.

  The case body 2 has light emitting diode illuminating devices A to E sequentially attached to the lamp mounting portion at the center of the inner surface of the top plate 2a. The light emitting diode illuminating devices A to E are mounted on the top surface of the top plate 2a in FIG. A lighting device 4 for lighting E is provided.

  At the center of the inner surface of the bottom plate 2 b of the case body 2, a glass-made, covered, bottomless cylindrical chamber case 5 is placed. The chamber case 5 accommodates a sample such as a dyed cloth cut to a required size (for example, 2 cm × 2.5 cm) on a sheet of neutral paper and with corners fixed with double-sided tape.

  Then, this exposure apparatus 1 is installed in a constant temperature and humidity room at a temperature of 20 ± 5 ° C. and a humidity of 60 ± 5%, and the temperature logger in the chamber case 5 under test is installed in the data logger (Trend Logger 2, ACR System Inc.). A digital illuminometer TOPCONIM-3 was used for illuminance measurement. The irradiation surface of the sample was adjusted to 500 lx, and exposure for 30 hours (corresponding to the annual limit exposure amount of 15,000 lx · hr based on the CIE standard) was repeated 10 times.

Color measurement of the test cloth before and after exposure was performed with Macbeth Color-Eye (registered trademark) 7000, Illuminant C, 400-800 nm (Macbeth, USA). The test cloth was placed on a white plate for white calibration of the colorimeter, and the color was measured three times with one sheet of cloth. The color difference ΔE before and after each exposure was calculated using the CIE 1976 L ^* a ^* b ^* formula (AATCC 1995).

The color difference formula of CIELAB can be obtained by the following formula.

(Experimental result)
Regarding the discoloration caused by the five types of blue scale light-emitting diode illumination devices A to E, the color difference of the blue scale grade 3 or higher did not exceed ΔE = 1.6 even at 150,000 lx · hr after the final exposure. There was a difference in fading of the blue scale even when the accumulated radiation intensity was the same. This is because the relationship between the spectral distribution of the light source and the working wavelength of the dye used is involved. Blue scale class 1 color difference ΔE = 1.6 was reached in 90,000 lx · hr of light emitting diode illuminators of A, B, and E in the shortest time, and the latest was 120 light emitting diode illuminators of D. 000 lx · hr, among the five types of light-emitting diode illuminating devices A to E, it was found that the light-emitting diode illuminating device of D has the highest fading-inhibiting effect. The time required to reach the blue scale first class color difference ΔE = 1.6 in the NU fluorescent lamp was 75,000 lx · hr for the general white fluorescent lamp and 120,000 lx · hr for the NU fluorescent lamp. All the light-emitting diode illuminating devices A to E have a fading-inhibiting effect as compared with the general white fluorescent lamp, and in particular, the light-emitting diode illuminating device D is almost equivalent to the NU fluorescent lamp.

  In terms of fading of Japanese yellow dyed fabrics, turmeric and yellowfin are significantly larger than other dyes. For example, even after exposure to 15,000 lx · hr, turmeric ΔE = 5 to 9.2 and yellowfin ΔE = 1.6 to 3.4 are fading. In particular, turmeric and yellowfin dyes are general-purpose dyes used in ukiyo-e, Kosode, scriptures, and paper, and their fading-inhibiting effect is important for museum and museum lighting. When turmeric and yellowfin are used as indicators of lamp performance, the order of the light emitting diode illuminating devices causing discoloration is A> E> B, C> D.

  In addition, dyed fabrics with a color difference ΔE = 1.6 or more after exposure to 15,000 lx · hr of white light emitting diode lighting devices A to E are yellow dyes, and visually visible in red, purple, blue dyes and blue scales. It turned out that no fading was felt. It has been shown that yellow dyes are particularly fading even in light emitting diode illuminators A to D without ultraviolet radiation.

  Furthermore, regarding the relative value of the color difference after the final exposure of the light-emitting diode illuminating devices B to E when the light-emitting diode illuminating device A having the highest color temperature is set to 1, with respect to the light-emitting diode illuminating device A for yellow dyes The light-emitting diode illuminating device B has 12%, the light-emitting diode illuminating device C has 15%, and the light-emitting diode illuminating device D has a 32% fading suppression effect, but the light-emitting diode illuminating device E is almost the same. In the whole dye, the light-emitting diode illuminating device B was almost the same as the light-emitting diode illuminating device A, the light-emitting diode illuminating device C was 10%, and the light-emitting diode illuminating device D was 20%. On the contrary, the device E has a large 10% fading, and the white light emitting diode illuminating devices A to E as a whole dye have a fading inhibiting effect in the order of D> C> B> A> E. It was found that a large fading-inhibiting effect can be obtained by using the light emitting diode illuminating device D.

  FIG. 1 shows radiation intensity (W) for each wavelength region of the light-emitting diode illuminators A to E, respectively. These radiant intensities (W) were calculated by the following calculation method.

(1) Measurement Items (1-1) Spectral Distribution Measurement First, as shown in FIG. 5, in each wavelength region of the visible light region (380 nm to 780 nm) of each of the light emitting diode illuminators A to E, at intervals of Δλ = 5 nm. Then, the relative radiation intensity Φ _eλ is measured.

(1-2) Total luminous flux measurement Also, based on CIE128 and JEL311, the total luminous flux (lm) of each of the light emitting diode illuminating devices A to E is obtained.

(2) Calculation method of radiant flux The relationship between the total luminous flux and the radiant flux is shown in the following equation (1).

  Therefore, according to this verification experiment, when the integrated irradiance is the same in these white light emitting diode illumination devices A to E, it has been found that the fading of the dyed cloth and the blue scale has a high correlation with the color temperature of the light source. Further, the light emitting diode illumination devices A to D that do not contain ultraviolet radiation do not cause fading than the light emitting diode illumination device E that contains ultraviolet radiation. Among them, yellow dyes are red, purple, and blue dyes. More fading than. Although there was no significant difference in the fading suppression effect between the light emitting diode illuminating device C and the light emitting diode illuminating device D in the entire dyed cloth, judging from the yellow dye and the color difference value of the first class of blue scale, five types of white light emitting diode illumination It has been found that among the devices A to E, the light-emitting diode illuminating device D has the highest fading suppression effect.

The figure which shows the list of the radiation intensity | strength for every several wavelength range in the white light emitting diode illuminating device AE which concerns on embodiment of this invention. The figure which shows the table | surfaces, such as the electrical property of the white light emitting diode illuminating device AE shown in FIG. (A)-(e) is each spectral distribution figure of light emitting diode illuminating device AE shown in FIG. The partially cutaway front view of the exposure apparatus used for verification experiments, such as the discoloration suppression effect of light emitting diode illuminating device AE shown in FIG. The figure which shows the spectral radiation intensity for demonstrating the calculation formula which calculates | requires the radiation intensity of the several wavelength range of light emitting diode illuminating device AE shown in FIG. FIG. 4 is a spectral distribution diagram in which spectral distributions of the light-emitting diode illuminators A to E shown in FIGS.

Explanation of symbols

A, B, C, D, E Light-emitting diode illumination device, 1 exposure device, 2 case body, 4 lighting device, 5 chamber case.

Claims (2)

A light emitting diode and a wavelength converter that converts light emitted from the light emitting diode into required color light, and a light emitting diode device that emits white light from the required color light and light emitted from the light emitting diode.
It has emission wavelength ranges of at least 400 to 500 nm, 500 to 600 nm, and 600 to 700 nm, and when these emission wavelength ranges are λ1, λn, and λh, respectively, the emission intensity of λ1 is 0 to ² W / m ² , λn. A light emitting diode illuminating device, wherein the radiation intensity of λh is set so that the radiation intensity of λ is approximately twice as large as λl and the average color rendering index is 70 or more. 2. The light-emitting diode illuminating apparatus according to claim 1, wherein the radiant intensity of λh is equal to or higher than the radiant intensity of λn, and the average color rendering index is 80 or higher.

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