JP2007122950A - Lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system capable of materializing illumination having color rendering properties by using light emitting diodes (LED), and capable of changing colors while changing brightness. <P>SOLUTION: This lighting system 20 has two or more lamps 10-14 selected from a group comprising lamps mounted with LEDs only and lamps having LEDs and phosphors excited by light thereof, and a control device capable of adjusting each light output of the lamp. The lamps are preferably two or more lamps selected from the group comprising a lamp made of a blue LED, a lamp having a blue LED and green phosphors, a lamp having the blue LED and red phosphors, a lamp having the blue LED and yellow or orange phosphors, and a lamp made of a green LED. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lighting device using a light emitting diode (hereinafter referred to as LED) that has high color rendering properties and can change color.

  For lighting applications, white light is required. Currently, white light can be obtained by the following method using an LED as a light source.

(1) Red LED + Green LED + Blue LED
This is a system that obtains white light by combining LEDs of three primary colors of light, and is used in backlights for liquid crystal display devices. Since the color rendering property is low, it is not suitable for lighting applications.

(2) Blue LED + Yellow phosphor A white LED is obtained by combining a blue LED and a yellow phosphor that emits yellow light that is a complementary color when excited by the blue light. Since this method has a simple structure and high efficiency, it is the current mainstream method for obtaining white light using an LED. However, in this method, since there are only blue light and yellow light, red light is insufficient for illumination, and the color cannot be changed. Non-Patent Document 1 describes an example in which a general blue LED + YAG phosphor having a peak wavelength of 465 nm is combined. The white LED according to this example has an average color rendering index Ra = 85, but it is not suitable for illumination because it contains almost no red component.

(3) Ultraviolet LED + RGB phosphor A method of obtaining white light by combining red, green, and blue phosphors with a purple or ultraviolet LED. Although the color rendering property can be increased because of the use of the RGB phosphor, the color cannot be changed even with this method.
Non-Patent Document 1 describes that an average color rendering index of 93 was achieved by this method in December 2002.

In Patent Document 1, two types of phosphors are excited by a blue or blue-green LED having a wavelength range of 450 to 500 nm, and yellow fluorescent light having a main wavelength range of 520 to 580 nm and 580 to 640 nm, respectively. It is described that a white light emitting device having excellent light emission characteristics can be obtained by generating a red fluorescent light and packaging the phosphor and the packaging material at a predetermined mixing ratio.
Application and future prospect of white LED lighting system technology, CM Publishing, author Tsunemasa Taguchi JP 2005-79500 A

If it is possible to change not only the brightness but also the color of the lighting device, depending on various factors such as the season, time, purpose of use of the illuminated space, type of exhibits and display goods, etc. Since an appropriate color can be selected and freely changed, the added value of the lighting device can be increased.
However, the illumination device using the conventional LED cannot change the color. Another method for changing the color of the lighting device is to use two light sources, a fluorescent lamp and an incandescent bulb, but this leads to an increase in the size and power consumption of the lighting device and a short life of the light source. There is a problem.

  In addition, the white light source described in Patent Document 1 is a combination of yellow and red phosphors and blue LEDs. In this case, the color rendering index such as green (R11) deteriorates, and an LED having a wavelength of around 500 nm is used. However, since the color rendering index of blue (R12) deteriorates, there is a problem in using it for illumination purposes.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an illuminating device that can realize illumination with high color rendering properties using LEDs, change brightness, and change color.

  In order to achieve the above object, the present invention comprises two or more lamps selected from the group consisting of a lamp having only a light emitting diode element and a lamp having a light emitting diode element and a phosphor excited by the light, And a control device capable of adjusting a light output of each of the lamps.

  In the illumination device of the present invention, the lamp includes a lamp (a) made of a blue light emitting diode element, a lamp (b) having a blue light emitting diode element and a green phosphor, and a lamp having a blue light emitting diode element and a red phosphor. (C) Two or more lamps selected from the group consisting of a lamp (d) having a blue light emitting diode element and a yellow or orange phosphor and a lamp (e) comprising a green light emitting diode element are preferred.

  The illuminating device of the present invention preferably includes at least the lamp (a), the lamp (b), and the lamp (c) among the lamps (a) to (e).

  The illuminating device of the present invention preferably includes a lamp (a), a lamp (b), a lamp (c), and a lamp (d) among the lamps (a) to (e).

  In the illumination device of the present invention, it is preferable that all of the lamps (a) to (e) are included.

  In the illuminating device of the present invention, at least two or more of the white ranges of daylight color, day white color, white color, warm white color, and light bulb color can be emitted, and the emitted white color range is JIS Z. It is preferable that the average color rendering index measured by the method defined in 8726 is 80 or more.

  In the illuminating device of the present invention, at least two or more of the white ranges of daylight color, day white color, white color, warm white color, and light bulb color can be emitted, and the emitted white color range is JIS Z. The color rendering AA or the color rendering AAA is preferable based on the light source color and color rendering properties defined in 9112.

The lighting device of the present invention includes two or more lamps selected from the group consisting of a lamp having only a light emitting diode element and a lamp having a light emitting diode element and a phosphor excited by the light, and each of the lamps. Because it has a configuration with a control device that can adjust the light output of the LED, it is possible to realize lighting with high color rendering properties using LEDs, and it is possible to change the color while changing the brightness, which is a high added value A lighting device can be provided.
For example, in the case of residential lighting, it is possible to use a warm white color with a cool color temperature in summer, and it is possible to illuminate with a warm light bulb color in winter. A positive alpha can be expected for the energy saving effect of the adoption. In addition, it is possible to use a daytime white color at night and change it to a light bulb color at midnight. In the past, two light sources, a fluorescent lamp and an incandescent lamp, were necessary. However, the lighting apparatus according to the present invention can be used alone.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a blue LED element (hereinafter abbreviated as blue LED), a green LED element (hereinafter abbreviated as green LED), a green phosphor, and a yellow fluorescence used in a lamp used in the lighting device of the present invention. It is a graph which shows the emission spectrum of each of a body and a red fluorescent substance.

  As shown in FIG. 1, a wide emission spectrum can be obtained by appropriately combining blue and green LEDs and green, yellow and red phosphors, and as a result, high color rendering can be realized. The materials of the green, yellow and red phosphors used in the lighting device of the present invention are not particularly limited, but are excited by blue light emitted from a blue LED and emit green light, yellow light and red light with high efficiency. Is desirable.

Moreover, it is preferable that each emission peak wavelength of blue and green LED used in the illuminating device of this invention and green, yellow, and red fluorescent substance shall be the following range.
The emission peak wavelength of the blue LED is preferably in the wavelength range of 435 to 480 nm.
The emission peak wavelength of the green LED is preferably in the range of 480 to 510 nm, more preferably the center ± 10 nm of the emission peak wavelength of the blue LED used and the emission peak wavelength of the green phosphor, and the emission peak wavelength of the blue LED and the green color. It is more preferable to have an emission peak wavelength centered on a wavelength obtained by adding the emission peak wavelength of the phosphor and dividing by 2.
The emission peak wavelength of the green phosphor is preferably in the range of 500 to 560 nm, and more preferably in the range of 500 to 530 nm.
The emission peak wavelength of the yellow or orange phosphor is preferably in the range of a wavelength of 560 to 610 nm, more preferably the center ± 10 nm between the emission peak wavelength of the green phosphor and the emission peak wavelength of the red phosphor.
The emission peak wavelength of the red phosphor is preferably in the wavelength range of 610 to 750 nm, and more preferably in the range of 640 nm to 680 nm.

  FIG. 2 is a cross-sectional view showing an example of a lamp used in the lighting device of the present invention. In this lamp 13, a blue LED 2 is mounted on a substrate 1 provided with a pair of electrodes 4A, 4B, a cup member 5 is provided around the substrate, and a yellow phosphor 3 is dispersed in a cup of the cup member 5. The transparent resin 7 is filled, cured, and sealed. The blue LED 2 is mounted on one electrode 4A, one electrode terminal on the blue LED 2 side is joined to one electrode 4A, and the other electrode terminal on the blue LED 2 side is connected by a wire 6 such as a gold thin wire. The other electrode 4B is electrically connected. In this example, an LED lamp having a surface mount package (SMD) structure is illustrated as the lamp 13, but the present invention is not limited to this, and a lamp having another structure, for example, an LED having a shell-type package structure. A lamp may be used.

The lamp 11 emits blue light by energizing the blue LED 2 to emit light, and part of the blue light is absorbed by the particulate yellow phosphor 3 to excite the yellow phosphor and emit yellow light. Thus, the yellow light and the blue light are irradiated outside the transparent resin 7.
In this lamp structure, if the yellow phosphor 3 is not dispersed in the transparent resin 7, a lamp that emits only blue light emitted from the blue LED 1 (or green LED) can be formed. Thus, by using a green phosphor or a red phosphor, or by using a mixture of two or more kinds of phosphors, a mixed light of light combined from the blue LED (or green LED) and light emitted from each phosphor can be obtained. An illuminated lamp can be constructed. The present invention is characterized by combining at least two kinds of lamps from these various combinations of lamps.

  In a preferred embodiment of the present invention, as a lamp, a lamp (a) comprising a blue LED, a lamp (b) having a blue LED and a green phosphor, a lamp (c) having a blue LED and a red phosphor, and a blue LED And two or more lamps selected from the group consisting of a lamp (d) having a yellow and orange phosphor and a lamp (e) comprising a green LED.

  In a more preferred embodiment, the lamp preferably includes at least the lamp (a), the lamp (b), and the lamp (c) among the lamps (a) to (e). It is more preferable to have a), a lamp (b), a lamp (c), and a lamp (d), and it is more preferable to have all of the lamps (a) to (e).

  FIG. 3 is a diagram showing a first embodiment of the illumination device of the present invention. The light emitting device 20 of the present embodiment includes a lamp 10 (lamp (a)) made of a blue LED, a lamp 11 (lamp (b)) having a blue LED and a green phosphor, and a lamp having a blue LED and a red phosphor. 12 (lamp (c)), a lamp 13 (lamp (d)) having a blue LED and a yellow or orange phosphor, a lamp 14 (lamp (e)) comprising a green LED, and these lamps 10, 11, 12 , 13, and 14, an LED driver circuit 15 capable of adjusting the light output, and a control device including an arithmetic device 16.

  The control device including the LED driver circuit 15 and the arithmetic device 16 is not particularly limited as long as the light output of each of the lamps 10, 11, 12, 13, and 14 can be adjusted. For example, the control device can emit lamps 10, 11, 12, 13, and 14 so that at least two or more colors in the range of daylight color, daylight white, white, warm white, and light bulb color can be emitted. It is possible to control the ON and OF of the lamps and to control the currents to the lamps 10, 11, 12, 13, and 14. In addition, for color switching, a method that switches to a specific color (for example, daylight color, day white color, white color, warm white color, light bulb color) with a single touch or a method that gradually switches the level based on color temperature, etc. is adopted. can do.

  In the illuminating device 20 of the present embodiment, at least two or more colors can be emitted from the white range of daylight color, day white color, white color, warm white color, and light bulb color, and the emitted white color range is white. The average color rendering index of 80 or more measured by the method defined in JIS Z 8726 is preferable.

  Further, in the lighting device 20 of the present embodiment, at least two or more colors can be emitted in the white range consisting of daylight color, day white color, white color, warm white color, and light bulb color, and in the white range of light emission. It is preferable that the color is color rendering AA or color rendering AAA according to classification according to light source color and color rendering properties defined in JIS Z 9112.

  Here, the definition and measurement method of the color rendering properties, the average color rendering index, and the special color rendering index in the lighting device of the present invention will be described.

(Color rendering)
Color rendering is a phenomenon in which colors appear differently depending on the illumination light source, and the characteristic is called color rendering. In general, the color rendering property represents the property of a light source compared with natural light. A method for evaluating the color rendering properties of the light source is defined in JIS Z 8726.

(Average color rendering index (Ra))
In general, the color rendering is expressed as “good” or “bad” with reference to light such as natural light. However, the illumination close to the natural light is used as a reference light, and the method is defined in JIS Z 8726. Examine the test light and evaluate the color rendering properties of the illumination light. The color rendering index includes an average color rendering index and a special color rendering index. The average color rendering index is the numerical value of the color shift when the test color is illuminated with the sample light source and the reference light. The value when the color is viewed with the reference light is set to 100, and the numerical value increases as the color shift increases. Becomes smaller. The average color rendering index (Ra) is the reference light No. It is expressed as an average value of 1 to 8 color rendering evaluation values.

In the standard of the color rendering index by the CIE (International Lighting Commission), desirable average color rendering index is as follows.
Ra ≧ 90 ... Color comparison / inspection, clinical trial, museum.
90> Ra ≧ 80... House, hotel, restaurant, store, office, school, hospital, etc. 80> Ra ≧ 60: Factory for general work.

(Special color rendering index (Ri))
Special color rendering index is a test color for special color rendering evaluation (No. 9-15), red, yellow, green, blue, western skin color, leaf color, Japanese skin color, and other realistic colors The numerical value is also displayed for each test color.

(Color rendering index of narrow-band light-emitting trend lamp and minimum value of three-wavelength radiant flux ratio (JIS Z 9112))
For reference, the rank of the color rendering index of fluorescent lamps is shown in Table 1.

  Thus, if the color of the emitted white range is an average color rendering index of 80 or more measured by the method defined in JIS Z 8726, and the color rendering AA or color rendering AAA is sufficient as a white light source for illumination. It can be put into practical use. The lighting device of the present embodiment will be described in detail in the examples described later, but can achieve an average color rendering index of 80 or more, and in Example 3, in particular, has a high color rendering index of about 95 average color rendering index. Can be realized.

  FIG. 4 is a diagram showing a second embodiment of the illumination device of the present invention. The illumination device 21 of the present embodiment includes a lamp 10 (lamp (a)) made of a blue LED, a lamp 11 (lamp (b)) having a blue LED and a green phosphor, a blue LED and red fluorescence on a substrate 17. A lamp 12 having a body (lamp (c)) is mounted, and an LED driver circuit 15 is mounted on the periphery of the substrate. The lamps 10, 11, 12 and the LED driver circuit 15 are electrically connected to each other. It is configured to connect to.

  The illuminating device 21 of the present embodiment emits the three types of lamps 10, 11, and 12 to emit light, thereby at least two or more of white ranges including daylight color, daylight white, white, warm white, and light bulb color. Colors can be emitted, and the emitted white color range has an average color rendering index of 80 or more, and the color rendering properties of color rendering AA can be realized.

  FIG. 5 is a diagram showing a third embodiment of the illumination device of the present invention. The illuminating device 22 of the present embodiment includes a lamp 10 (lamp (a)) made of a blue LED and a lamp 11 (lamp (b)) having a blue LED and a green phosphor on a substrate 17 in which the LED driver circuit 15 is built. 3) A lamp 12 (lamp (c)) having a blue LED and a red phosphor is mounted, and the lamps 10, 11, 12 and the LED driver circuit 15 are electrically connected. ing. The illuminating device 22 according to the present embodiment emits the three types of lamps 10, 11, and 12 to emit light, so that at least two or more of white ranges of daylight color, daylight white, white, warm white, and light bulb color can be obtained. Colors can be emitted, and the emitted white color range has an average color rendering index of 80 or more, and the color rendering properties of color rendering AA can be realized.

[Example 1]
A lamp 10 (lamp (a)) made of a blue LED, a lamp 11 (lamp (b)) having a blue LED and a green phosphor (TGGreen), and a lamp 12 (lamp) having a blue LED and a red phosphor (SCSRed) An illumination device was manufactured by combining the three types of lamps of (c)). White light can be realized by red light emission + green light emission + blue light emission.

  Among the phosphors used (see the emission spectrum of FIG. 1), the red phosphor has an emission peak wavelength of 625 nm and a full width at half maximum of 70 nm, the green phosphor has an emission peak wavelength of 530 nm and a full width at half maximum of 50 nm, and a blue LED. The emission peak wavelength is 460 nm. The color range that can be realized by combining these is the range indicated by the triangle in FIG. 6A in the xy chromaticity diagram shown in FIG. 6, and the white range (daylight color, daylight white, white, warm white, light bulb color). Can be covered enough.

  Table 2 shows measured values such as the average color rendering index (Ra) at each white color which is important as an illumination light source, and FIG. 6B shows the chromaticity coordinates at that time.

As shown in Table 2, it can be seen that the lighting device manufactured in this example can achieve an average color rendering index of about 80 for each white color and can be applied to lighting applications.
In addition, Table 3 shows the peak intensity ratio of each of these white colors.

  By setting the light intensity of each lamp so as to have such blue, red, and green peak intensities, the chromaticity and color rendering properties shown in Table 2 were realized. As an example of the color obtained in this embodiment, a white spectrum is shown in FIG.

[Example 2]
A lamp 10 (lamp (a)) made of a blue LED, a lamp 11 (lamp (b)) having a blue LED and a green phosphor (TGGreen), and a lamp 12 (lamp) having a blue LED and a red phosphor (SCSRed) (C)), an illuminating device in which four types of lamps 13 (lamp (d)) having a blue LED and a yellow phosphor were combined was produced.

  Even in Example 1 in which three types of lamps (a), (b), and (c) were combined, a color rendering index of about 80 could be realized, but a yellow phosphor was added to further improve the color rendering index. I tried to improve the color rendering index. In Example 1, R9 showing red color rendering was low, but R9 was also improved by adding a yellow phosphor.

The same green phosphor and red phosphor as in Example 1 were used, and YAG: Ce (cerium-added yttrium / aluminum / garnet) phosphor was used as the yellow phosphor. Note that even if a yellow phosphor is added, the color range that can be realized is the same as in the case of the first embodiment and does not change greatly.
Table 4 shows measured values such as the average color rendering index (Ra) at each white color important as illumination, and FIG. 8 shows the chromaticity coordinates at that time.

As can be seen from the results in Table 2, the color rendering index (Ra) was improved as compared with Example 1 due to the effect of adding yellow, and the values of R9 and R15 were also increased.
Table 5 shows peak intensity ratios for realizing these.

  In this embodiment, an example on a black body radiation locus is shown to evaluate the color rendering index, but in order to prevent the driver circuit from becoming complicated, even if the green output is fixed, the colors in each color range Can be realized. However, in this case, there is a possibility of deviating from the black body radiation locus, or the color rendering index may be slightly deteriorated.

  As an example of the color obtained in this embodiment, a white spectrum is shown in FIG.

[Example 3]
A lamp 10 (lamp (a)) made of a blue LED, a lamp 11 (lamp (b)) having a blue LED and a green phosphor (TGGreen), and a lamp 12 (lamp) having a blue LED and a red phosphor (SCSRed) (C)), an illuminating device in which five types of lamps including a lamp 13 (lamp (d)) having a blue LED and a yellow phosphor and a lamp 14 (lamp (e)) made of a green LED were combined was manufactured.

Also in Example 2, since the values of R11 and R12 are low, the color rendering AAA cannot be realized by the color rendering properties. In the spectrum of Example 2 shown in FIG. 9, the presence of a dent in the vicinity of a wavelength of 500 nm is considered to be a cause of a low color rendering index, and a lamp composed of a green LED was added to the lamp configuration of Example 2. The green LED used was an emission peak wavelength of 500 nm (blue-green LED manufactured by OPT). Other phosphors and blue LEDs were the same as those in Example 2.
Table 6 shows measured values such as the average color rendering index (Ra) at each white color important as illumination, and FIG. 10 shows the chromaticity coordinates at that time.

As shown in Table 6, the addition of the green LED was effective in improving the special color rendering index (R9 to R15), and the color rendering AAA was realized with the light bulb color.
Table 7 shows the peak intensity ratios for realizing these.

  As an example of the color obtained in this embodiment, a white spectrum is shown in FIG. From FIG. 11, it can be seen that in the illumination device of this example, the depressions near the wavelength of 500 nm are reduced.

[Comparative Example 1]
The color rendering properties of a three-wave LED combining a commercially available red LED, green LED, and blue LED were examined. The emission spectrum of each LED is shown in FIG.
In this three-wave type LED, each color in the white range (daylight color, daylight white, white, warm white, light bulb color) can be realized by changing the light output of the red, green, and blue LEDs.
Table 8 shows measured values such as the average color rendering index (Ra) for each white color important as illumination.

As shown in Table 8, the calculation result of the color rendering properties is very low compared to the cases of Examples 1 to 3 described above.
The three-wave type LED can realize various colors by changing the light output of the red, green, and blue LEDs, but the color rendering property is very low because each emission wavelength is narrow.
As the emission wavelength of each LED is narrower, the color purity becomes higher and a variety of colors can be realized. Therefore, there is a contradiction between the demand for the current three-wave LED and the improvement in color rendering.

[Comparative Example 2]
Table 9 shows values such as the average color rendering index (Ra) of commercially available white LEDs (blue LED + phosphor method).

As shown in Table 9, the average color rendering index was about 72-80.
The CIE (International Commission on Illumination) recommends an average color rendering index (Ra) of 80 or more for lighting sources for offices and living rooms, and the Ra value alone is somewhat insufficient.
However, since R9 indicating red color rendering is low, all reddish colors appear dull, and for example, human face colors appear dull, making them unsuitable as illumination light sources.

It is a figure which shows each emission spectrum of blue used for the lamp | ramp of the illuminating device of this invention, LED, green, yellow, and red fluorescent substance. It is sectional drawing which shows the structure of a lamp | ramp. It is a block diagram of the illuminating device of 1st Embodiment of this invention. It is a block diagram of the illuminating device of 2nd Embodiment of this invention. It is a block diagram of the illuminating device of 3rd Embodiment of this invention. It is a figure which shows the chromaticity range of the illuminating device of Example 1. FIG. It is a figure which illustrates the spectrum of the illuminating device of Example 1. FIG. It is a figure which shows the chromaticity range of the illuminating device of Example 2. FIG. It is a figure which illustrates the spectrum of the illuminating device of Example 2. FIG. It is a figure which shows the chromaticity range of the illuminating device of Example 3. FIG. It is a figure which illustrates the spectrum of the illuminating device of Example 3. It is a figure which shows the emission spectrum of LED of each color used in the comparative example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2 ... Blue LED, 3 ... Yellow fluorescent substance, 4A, 4B ... Electrode, 5 ... Cup member, 6 ... Wire, 7 ... Transparent resin 10, 11, 12, 13, 14 ... Lamp, 15 ... LED Driver circuit, 16 ... arithmetic device, 17 ... substrate, 20, 21, 22 ... lighting device.

Claims (7)

  Two or more lamps selected from the group consisting of a lamp having only a light emitting diode element and a lamp having a light emitting diode element and a phosphor excited by the light, and the light output of each lamp can be adjusted A lighting device comprising: a control device.   The lamp comprises a lamp (a) comprising a blue light emitting diode element, a lamp (b) having a blue light emitting diode element and a green phosphor, a lamp (c) having a blue light emitting diode element and a red phosphor, and a blue light emitting diode. 2. The lamp according to claim 1, wherein the lamp comprises two or more lamps selected from the group consisting of a lamp (d) having an element and a yellow or orange phosphor and a lamp (e) comprising a green light emitting diode element. Lighting device.   The lighting device according to claim 2, comprising at least the lamp (a), the lamp (b), and the lamp (c) among the lamps (a) to (e).   The lamp according to claim 2, wherein the lamp (a) to the lamp (e) include a lamp (a), a lamp (b), a lamp (c), and a lamp (d). apparatus.   The lighting device according to claim 2, comprising all of the lamps (a) to (e).   It is possible to emit at least two colors in the white range consisting of daylight color, day white color, white color, warm white color, and light bulb color, and the color of the emitted white color range is determined by the method defined in JIS Z 8726. The lighting device according to claim 1, wherein the measured average color rendering index is 80 or more. It is possible to emit at least two colors of the daylight color, the daylight white, the white, the warm white, and the white range of the light bulb color, and the color of the emitted white range is a light source color defined in JIS Z 9112 The lighting device according to claim 1, wherein the lighting device is color rendering AA or color rendering AAA according to color rendering properties.

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