JP2010186725A - Illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve an illumination device having low color temperature, small deviation from a blackbody locus, high color rendering properties, and high light emission efficiency by using an LED. <P>SOLUTION: A white LED 121 includes an LED element 212 (first light-emitting diode) and a silicone resin 213 into which phosphor is mixed. A red LED 122 includes an LED element 222 (second light-emitting diode). The LED element 212 emits light having about 460 nm (first wavelength) of the main wavelength, the phosphor emits fluorescence having about 560 nm (second wavelength), and the LED element 222 emits the light having about 635 nm (third wavelength) of the main wavelength. As for a color temperature conversion filter 150 (optical component), its transmissivity at about 460 nm is lower than those of about 560 nm and about 635 nm, and the light emitted by the LED element 212, the phosphor, and the LED element 222 is transmitted therethrough. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illuminating device using a light emitting diode (LED).

As a white LED, a combination of an LED element that emits short-wavelength light such as blue and a phosphor that converts wavelength of short-wavelength light emitted from the LED element into long-wavelength light is widely used.
A white LED according to such a system has low color rendering properties, and if the color temperature of emitted light is set to 5000 K (Kelvin) or less, the light emission efficiency is deteriorated.
In the case where a white LED is used for the lighting device, there is a technique for reducing the color temperature, increasing the color rendering property, and increasing the light emission efficiency by mixing the light emitted from the white LED and the light emitted from the red LED.

JP 2003-298118 A

It is desirable that the light emitted from the lighting device has chromaticity coordinates with a small deviation from the black body locus. For this reason, light emitted from a general white LED has chromaticity coordinates with a small deviation from the black body locus.
When the light emitted from the white LED and the light emitted from the red LED are mixed, the chromaticity coordinates of the mixed light move in the right direction on the chromaticity diagram, and the deviation from the black body locus increases.
The present invention has been made, for example, in order to solve the above-described problems. In an illumination device using a white LED, a low color temperature of 5000 K or less is realized, and a deviation from a black body locus is small. An object of the present invention is to obtain a lighting device having high color rendering properties and high luminous efficiency.

The lighting device according to the present invention includes:
A first light emitting diode emitting light having a first wavelength as a dominant wavelength;
A phosphor that emits fluorescence having a second wavelength longer than the first wavelength as a main wavelength by light emitted from the first light emitting diode;
A second light emitting diode that emits light having a third wavelength longer than the second wavelength as a dominant wavelength;
The transmittance of the first wavelength is lower than the transmittance of the second wavelength and the third wavelength, and the light emitted from the first light emitting diode, the phosphor and the second light emitting diode is emitted. And a transmissive optical component.

  According to the illumination device of the present invention, the optical component transmits the light emitted from the first light emitting diode, the phosphor, and the second light emitting diode, and the first wavelength component is kept low. Light having a low temperature, a small deviation from the black body locus, high luminous efficiency, and excellent color rendering properties can be emitted.

FIGS. 3A and 3B are a perspective view and an exploded perspective view illustrating an example of a lighting device 100 according to Embodiment 1. FIGS. The bottom view and side view BB sectional drawing which show an example of the structure of the illuminating device 100 in Embodiment 1. FIG. FIG. 3 is a graph showing an example of spectral characteristics and light distribution characteristics of the white LED 121 and the red LED 122 in the first embodiment. FIG. 4 is a graph showing an example of light distribution characteristics of the white LED 121 and the red LED 122 in the first embodiment. FIG. 4 is a graph showing an example of transmission spectrum characteristics of a color temperature conversion filter 150 according to Embodiment 1. FIG. 4 is a graph illustrating an example of spectral characteristics of light emitted from the lighting device 100 according to Embodiment 1. FIG. 3 is a chromaticity coordinate diagram illustrating an example of chromaticity coordinates of light emitted from the illumination device 100 according to Embodiment 1. Explanatory drawing for demonstrating the effect | action of the diffusion sheets 141 and 142 in Embodiment 1. FIG. Side surface sectional drawing which shows an example of the structure of the illuminating device 100 in Embodiment 2. FIG. The bottom view and side view BB sectional drawing which show an example of the structure of the illuminating device 100 in Embodiment 3. FIG. FIG. 10 is a perspective view illustrating an example of an appearance of a lighting device 100 according to Embodiment 4. FIG. 10 is an exploded perspective view showing an example of the internal structure of lighting apparatus 100 according to Embodiment 4. FIG. 10 is an exploded perspective view showing an example of the internal structure of lighting apparatus 100 according to Embodiment 5. FIG. 16 is an exploded perspective view showing another example of the internal structure of lighting apparatus 100 according to Embodiment 5.

Embodiment 1 FIG.
The first embodiment will be described with reference to FIGS.

FIG. 1 is a perspective view and an exploded perspective view showing an example of a lighting device 100 according to this embodiment.
The lighting device 100 includes a housing 110, a substrate 120, a reflector 130, two diffusion sheets 141 and 142, a color temperature conversion filter 150, and a frame 160.

The case 110 has a disk shape and has heat radiation fins on the back side. The housing 110 is made of a material having high thermal conductivity such as aluminum, for example, and releases the heat in the lighting device 100 to the outside.
A circuit pattern for lighting the white LED 121 and the red LED 122 is printed on the substrate 120 (LED substrate). A white LED 121 and a red LED 122 are mounted on the substrate 120. The base material of the substrate 120 is, for example, aluminum, paper phenol, glass epoxy, or the like. The base material of the substrate 120 is preferably a material having high thermal conductivity such as aluminum in order to release heat generated by the white LED 121 and the red LED 122.
The reflector 130 has a mortar shape, and has holes at positions corresponding to the white LEDs 121 and the red LEDs 122 on the substrate 120. The reflector 130 is made of, for example, a highly reflective polycarbonate resin, and diffusely reflects light emitted from the white LED 121 and the red LED 122.
The two diffusion sheets 141 and 142 have a disk shape and sandwich the color temperature conversion filter 150. The diffusion sheets 141 and 142 are, for example, PET (Polyethylene terephthalate) sheets coated with glass beads on the surface, and diffuse the light emitted from the white LED 121 and the red LED 122 to make the light emitted from the illumination device 100 uniform. .
The color temperature conversion filter 150 transmits part of the light emitted from the white LED 121 and the red LED 122 and absorbs or reflects part of the light. The color temperature conversion filter 150 is formed, for example, by mixing a coloring material such as a pigment in acrylic, polycarbonate, glass, or the like. The transmittance of the color temperature conversion filter 150 varies depending on the wavelength of light.
The frame 160 is generally cylindrical and surrounds the entire lighting device 100. The frame 160 is formed of a material having high thermal conductivity such as aluminum, for example, and releases the heat in the lighting device 100 to the outside.

  The substrate 120 and the frame 160 are fixed to the housing 110 with, for example, screws. The reflector 130, the diffusion sheet 141, the color temperature conversion filter 150, and the diffusion sheet 142 are held by being sandwiched between the substrate 120 and the frame 160, for example.

FIG. 2 is a bottom view and a side view BB sectional view showing an example of the structure of the illumination device 100 according to this embodiment.
The illumination device 100 includes, for example, five white LEDs 121 and one red LED 122. The number ratio of the white LED 121 and the red LED 122 may be different depending on the set value of the color temperature of the light emitted from the lighting device 100. Further, the number of red LEDs 122 may be larger than the number of white LEDs 121.

The white LED 121 includes a package 211, an LED element 212 (first light emitting diode), and a silicone resin 213.
The package 211 is made of, for example, ceramics, resin, metal, or the like. The package 211 has a recess. The LED element 212 is located at the center of the recess of the package 211. The LED element 212 is a blue light-emitting diode element having, for example, 460 nm (nanometer) (first wavelength) as a main wavelength (wavelength at which the intensity is maximum). The LED element 212 is electrically connected to an electrode provided in the package 211 through a wire such as a wire (not shown), and is lit by electric power supplied from the electrode. The silicone resin 213 is filled in the concave portion of the package 211, covers the LED element 212, and protects the LED element 212. A phosphor is mixed in the silicone resin 213. The phosphor mixed in the silicone resin 213 is, for example, a YAG (Yttrium Aluminum Garnet) phosphor, which is excited by light emitted from the LED element 212 and has a spectral width of 480 to 780 nm and a wavelength around 560 nm (second wavelength). ) Emits fluorescence having a dominant wavelength. The white LED 121 emits light that looks white as a whole by mixing light emitted from the LED element 212 and fluorescence emitted from the phosphor.

  The structure of the red LED 122 is substantially the same as that of the white LED 121 except for the following points. The LED element 222 of the red LED 122 is a red light emitting diode element having a main wavelength of, for example, 635 nm (third wavelength). The phosphor is not mixed in the silicone resin 223 of the red LED 122. The concave portion of the package 221 of the red LED 122 is different in shape from the white LED 121, and the red LED 122 has a light distribution characteristic different from that of the white LED 121.

The diffusion sheet 141 has a rougher surface on the back surface 236 (incident surface) than on the front surface 231 (output surface). The diffusion sheet 141 is disposed with the back surface 236 facing the color temperature conversion filter 150 and the front surface 231 facing the white LED 121 and the red LED 122.
Similarly, the back surface 237 of the diffusion sheet 142 is rougher than the front surface 232. The diffusion sheet 142 is disposed with the back surface 237 facing the color temperature conversion filter 150 and the front surface 232 facing the outside of the lighting device 100.

FIG. 3 is a graph showing an example of spectral characteristics of the white LED 121 and the red LED 122 in this embodiment.
The horizontal axis represents the wavelength, and the vertical axis represents the spectral intensity. A spectrum curve 411 represents the emission spectrum characteristic of the white LED 121. A spectrum curve 412 represents the emission spectrum characteristic of the red LED 122.

As described above, the light emitted from the white LED 121 has light having a strong emission spectrum peak around 460 nm emitted from the LED element 212 and a gentle emission spectrum peak around 560 nm emitted from the phosphor mixed in the silicone resin 213. The light is a synthesized light having a spectral width of 450 to 780 nm as a whole.
On the other hand, the light emitted from the red LED 122 is light having a strong emission spectrum peak around 635 nm emitted from the LED element 222 and has a spectrum width of 610 to 650 nm.

FIG. 4 is a graph showing an example of the light distribution characteristics of the white LED 121 and the red LED 122 in this embodiment.
The horizontal axis represents the angle from the front direction of the LED, and the vertical axis represents the relative luminous intensity relative to the luminous intensity in the front direction (0 degree direction). A light distribution curve 421 represents the light distribution characteristic of the white LED 121. A light distribution curve 422 represents the light distribution characteristic of the red LED 122.

Comparing the light distribution characteristic of the white LED 121 and the light distribution characteristic of the red LED 122, the red LED 122 has a wider angle light distribution characteristic. Thereby, the light emitted from the small number of red LEDs 122 reaches the entire diffusion sheet 141 and is evenly mixed at substantially the same ratio as the light emitted from the large number of white LEDs 121.
In the case where the number of white LEDs 121 and the number of red LEDs 122 are substantially equal, the light distribution characteristics of the white LEDs 121 and the light distribution characteristics of the red LEDs 122 may be the same. Conversely, when the number of white LEDs 121 is smaller than the number of red LEDs 122, the white LEDs 121 have a wider light distribution characteristic than the red LEDs 122.

FIG. 5 is a graph showing an example of the transmission spectrum characteristic of the color temperature conversion filter 150 in this embodiment.
The horizontal axis represents the wavelength, and the vertical axis represents the transmittance. The transmittance curve 431 represents the rate at which the color temperature conversion filter 150 transmits light of that wavelength.
The color temperature conversion filter 150 transmits 90% or more of light having a long wavelength such as a green component (480 nm to 580 nm) or a red component (580 nm to 780 nm), and cuts light having a short wavelength such as a blue component (380 nm to 480 nm). It is a filter. For example, the light near the wavelength of 460 nm emitted from the LED element 212 of the white LED 121 is transmitted by about 50%, and the light near the wavelength of 560 nm emitted from the phosphor or the light near the wavelength of 635 nm emitted from the LED element 222 of the red LED 122 is about Transmits 90% or more.

FIG. 6 is a graph showing an example of spectral characteristics of light emitted from the illumination device 100 according to this embodiment.
The horizontal axis represents the wavelength, and the vertical axis represents the spectral intensity. A spectral curve 413 represents the spectral characteristics of the light emitted from the illumination device 100.
In this example, the power input ratio between the white LED 121 and the red LED 122 is 3: 1. The white LED 121 has a luminous efficiency of 97 lm / W (lumen per watt), and the red LED 122 has a luminous efficiency of 38 lm / W.

  The light emitted from the white LED 121 and the light emitted from the red LED 122 are incident on the diffusion sheet 141 directly or after being reflected by the reflector 130. The diffusion sheet 141 diffuses incident light and mixes light emitted from the white LED 121 and light emitted from the red LED 122. The light diffused by the diffusion sheet 141 enters the color temperature conversion filter 150, and the color temperature conversion filter 150 cuts the short wavelength component. The light transmitted through the color temperature conversion filter 150 is incident on the diffusion sheet 142, and the diffusion sheet 142 further diffuses the incident light. The lighting device 100 emits light diffused by the diffusion sheet 142.

  When the color temperature conversion filter 150 cuts the short wavelength component, the light near the wavelength of 460 nm emitted by the LED element 212 of the white LED 121 is significantly cut, and the wavelength that is the main wavelength of the fluorescence emitted by the phosphor of the white LED 121 Light in the vicinity of 560 nm and light emitted from the LED element 222 of the red LED 122 are emitted almost as they are. Thereby, the peak intensity of the blue component becomes smaller than the peak intensity of the green component and the red component.

FIG. 7 is a chromaticity coordinate diagram illustrating an example of chromaticity coordinates of light emitted from the illumination device 100 according to this embodiment.
The horizontal axis represents chromaticity x, and the vertical axis represents chromaticity y. A black body locus 451 is a locus of chromaticity coordinates of the black body radiation. A spectrum locus 452 represents a locus of chromaticity coordinates of single wavelength light.

The chromaticity coordinates 441 are chromaticity coordinates of light emitted from the white LED 121. The chromaticity coordinates 442 are chromaticity coordinates of light emitted from the red LED 122. The chromaticity coordinates 443 are chromaticity coordinates of light obtained by mixing the light emitted from the white LED 121 and the light emitted from the red LED 122. The chromaticity coordinates 444 represent chromaticity coordinates of light that passes through the color temperature conversion filter 150 and is emitted from the lighting device 100.
The chromaticity coordinate A is the chromaticity coordinate of the standard light source A. The chromaticity coordinate C is the chromaticity coordinate of the standard light source C. The chromaticity coordinate D65 is the chromaticity coordinate of the standard light source D65.

For example, the chromaticity coordinate 441 of the light emitted from the white LED 121 is (x, y) = (0.3439, 0.3551), the correlated color temperature Tcp is about 5057 K, and the deviation Duv (= 1000 duv) is about 2. The chromaticity coordinate 442 of the light emitted from the red LED 122 is (0.7015, 0.2984).
The chromaticity coordinates 443 of the light obtained by mixing the light emitted from the white LED 121 and the light emitted from the red LED 122 are on a line segment connecting the chromaticity coordinates 441 and the chromaticity coordinates 442. For example, (x, y ) = (0.3913, 0.3476). The correlated color temperature Tcp is about 3443K, and the deviation Duv is about -17.
The chromaticity coordinate 444 of the light transmitted through the color temperature conversion filter 150 and emitted from the lighting device 100 is moved in the upper right direction because the short wavelength component is cut, for example, (x, y) = (0.4305, 0.3971), the correlated color temperature Tcp is about 3053 K, and the deviation Duv is about -2.

  The light emitted from the illumination device 100 has a luminous efficiency of, for example, about 75 lm / W and an average color rendering index Ra (hereinafter referred to as “color rendering”) of about 90. On the other hand, when the light obtained by mixing the light emitted from the white LED 121 and the light emitted from the red LED 122 by the diffusion sheets 141 and 142 is emitted as it is without passing through the color temperature conversion filter 150, the luminous efficiency is about 82 lm / W. The color rendering properties are about 90.

In general, it is desirable that the color tone of light emitted from the lighting device has a chromaticity coordinate on a black body locus or a small deviation from the black body locus.
The white LED generally has a small deviation from the black body locus of the chromaticity coordinates of the emitted light, and is within a range of, for example, about ± 2.
When the light emitted from the red LED is mixed with this, the correlated color temperature is lowered and the color rendering is increased, but the absolute value of the deviation from the black body locus is increased.
Therefore, by using the color temperature conversion filter 150 to cut light with a short wavelength, the absolute value of the deviation from the black body locus can be reduced. In addition, the correlated color temperature is further lowered.
Further, the light cut by the color temperature conversion filter 150 is short-wavelength light with low visibility, so that the apparent brightness does not decrease much, high luminous efficiency can be maintained, and color rendering is also high.

  FIG. 8 is an explanatory diagram for explaining the operation of the diffusion sheets 141 and 142 in this embodiment.

  When the illuminating device 100 is turned off, the emission surface (the diffusion sheet 142) from which the illuminating device 100 emits light looks like the color of light reflected from the external light 511. This light is light reflected by the interfaces of the two diffusion sheets 141 and 142 and the color temperature conversion filter 150 and the reflection plate 130.

The transmitted light 514 that passes through the color temperature conversion filter 150 includes a lot of long wavelength components such as green and red. For this reason, the external light reflected after passing through the color temperature conversion filter 150 becomes yellowish light containing many long wavelength components such as green and red.
For this reason, as the ratio of the light reflected after passing through the color temperature conversion filter 150 in the light reflected from the external light 511 on the exit surface of the illumination device 100 increases, the exit surface of the illumination device 100 becomes yellowish. It will look like it.
In this embodiment, the diffusion sheet 142 is disposed outside the color temperature conversion filter 150. For this reason, the light that has reflected the external light 511 on the exit surface of the illumination device 100 includes the light 512 that has been interface-reflected by the diffusion sheet 142 before reaching the color temperature conversion filter 150. The light 512 is substantially the same color as the outside light 511. Furthermore, since the surface 232 of the diffusion sheet 142 is the surface with the smoother surface roughness, interface reflection is relatively likely to occur. For this reason, the emission surface of the illumination device 100 looks almost the same color as the external light 511.

When the lighting device 100 is turned on, the direct light emitted from the white LED 121 and the red LED 122 or the reflected light reflected by the reflector 130 enters the diffusion sheet 141 as incident light 521.
Of the diffused light 523 diffused by the diffuser sheet 141 from the incident light 521, the transmitted light 524 that has passed through the color temperature conversion filter 150 is diffused by the diffuser sheet 142 to become diffused light 525, which is emitted to the outside. On the other hand, part of the incident light 521 is reflected at each interface between the two diffusion sheets 141 and 142 and the color temperature conversion filter 150.
Most of this light is incident light 521 that is reflected by the reflector 130 and incident on the diffusion sheet 141 again. For this reason, the light emitted from the white LED 121 and the light emitted from the red LED 122 can be further mixed.

The lighting device 100 in this embodiment includes a first light emitting diode (LED element 212), a phosphor (mixed in the silicone resin 213), a second light emitting diode (LED element 222), and an optical component ( Color temperature conversion filter 150).
The first light emitting diode emits light having a first wavelength (about 460 nm) as a main wavelength.
The phosphor emits fluorescence having a second wavelength (about 560 nm) longer than the first wavelength as a main wavelength by light emitted from the first light emitting diode.
The second light emitting diode emits light having a third wavelength (approximately 635 nm) longer than the second wavelength as a main wavelength.
The optical component has a transmittance (about 50%) of the first wavelength lower than a transmittance (about 90%) of the second wavelength and the third wavelength, and the first light emitting diode and the Transmits light emitted by the phosphor and the second light emitting diode.

  According to the illumination device 100 in this embodiment, since the optical component transmits the light emitted from the first light emitting diode, the phosphor, and the second light emitting diode, and the first wavelength component is kept low, Correlated color temperature Tc is low, deviation Duv from the black body locus is small, light emission efficiency is high, and light with excellent color rendering can be emitted.

The illuminating device 100 in this embodiment has the number of the first light emitting diodes (LED elements 212) larger than the number of the second light emitting diodes (LED elements 222).
The second light emitting diode has a light distribution characteristic that illuminates a wider area than the light distribution characteristic of the first light emitting diode.

  According to the illumination device 100 in this embodiment, the first light emitting diode emits light because the second light emitting diode has a light distribution characteristic that illuminates a wider area than the light distribution characteristic of the first light emitting diode. Light and the light emitted by the second light emitting diode can be mixed well.

As described above, depending on the color temperature of the light emitted from the lighting device 100, the lighting device 100 has a larger number of the second light emitting diodes (LEDs) than the number of the first light emitting diodes (LED elements 212). A structure including the element 222) may be employed.
In that case, if the first light emitting diode has a light distribution characteristic that illuminates a wider area than the light distribution characteristic of the second light emitting diode, the light emitted from the first light emitting diode and the second light emitting diode are emitted. The light emitted from the diode can be well mixed.

The illumination device 100 in this embodiment further includes a diffusion sheet 142.
The diffusion sheet 142 includes an incident surface (back surface 237) on which light transmitted through the optical component (color temperature conversion filter 150) is incident, and light incident on the incident surface with a finer surface roughness than the incident surface (reflection). A light exit surface (surface 232) that emits light (diffused light 516, 525) obtained by diffusing light 515 and transmitted light 524).

  According to the illumination device 100 in this embodiment, since the interface reflection on the exit surface is relatively large, the exit surface does not appear to be colored even when the light is extinguished, and the appearance is excellent.

The illuminating device 100 described above includes a housing 110, white LEDs 121 and red LEDs 122 installed in the housing 110, and a color temperature conversion in which the blue component absorption rate is larger than the green component and red component absorption rates. And a filter 150.
By emitting the light from the LED through the color temperature conversion filter 150 in which the absorptivity of the blue component is larger than that of the green component and the red component, the color tone of the mixed light of the white LED 121 and the red LED 122 is easy. It is possible to obtain an illuminating device that has high luminous efficiency and color rendering even at a color temperature of 5000 K or less, and that the chromaticity coordinates substantially coincide with the chromaticity coordinates of the same color temperature of the reference light (black body locus). it can.
In other words, a light source having a low color temperature having chromaticity coordinates on a black body locus, which is light of a color tone originally required for a lighting device, can be realized with high efficiency.

In the illumination device 100 described above, the light distribution distribution of the smaller LED of the white LED 121 and the red LED 122 is wider than the light distribution of the larger LED.
As a result, an almost constant color mixture ratio is obtained over the entire emission surface, and an illumination device with little color unevenness can be easily obtained.

In the illuminating device 100 described above, the diffusion sheet 142 is disposed on the emission surface side of the color temperature conversion filter 150 so that the surface with the fine surface roughness is the surface far from the color temperature conversion filter 150. .
Thereby, coloring of the output surface at the time of light extinction can be reduced.

  By changing the transmission spectrum characteristics of the color temperature conversion filter 150, the number of white LEDs 121 and the red LEDs 122, and the ratio of input power, an illumination device that emits light having a lower color temperature such as 3500K or 3000K can be easily configured. be able to.

In addition, a prism sheet, a lens, or the like may be provided on the exit surface of the lighting device 100. Thereby, the lighting device 100 can have an arbitrary light distribution characteristic.
Or it is good also as a structure which does not provide the diffusion sheets 141 and 142.

  Further, the lighting device 100 may have a blue LED or a green LED in addition to the white LED 121 and the red LED 122. As a result, the number of colors to be mixed increases, so that the color tone can be easily adjusted.

  Moreover, the illuminating device 100 is good also as a structure which has the function to light-control LED of each color independently. Thereby, it is possible to easily adjust the chromaticity shift of the mixed color light due to the variation of the LEDs. Moreover, it is good also as a structure which can implement | achieve the light of a user's favorite hue easily using a light control function.

Embodiment 2. FIG.
The second embodiment will be described with reference to FIG.
In addition, about the part which is common in Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 9 is a side sectional view showing an example of the structure of the illumination device 100 according to this embodiment.
The lighting device 100 is different from the first embodiment in that the lighting device 100 does not include the color temperature conversion filter 150. Instead, for example, a blue absorber is mixed into the material of the reflector 130 so that the reflector 130 absorbs light having a short wavelength such as blue. The reflector 130 has a low reflectance of light having a short wavelength such as blue, and a reflectance of light having a long wavelength such as green or red is high.

Part of the light emitted from the white LED 121 and the red LED 122 is directly incident on the diffusion sheet 141, and the rest is reflected on the reflection plate 130 and then incident on the diffusion sheet 141. A part of the light incident on the diffusion sheet 141 is interface-reflected by the surface 231 and the rest is diffused by the diffusion sheet 141. The light diffused by the diffusion sheet 141 further enters the diffusion sheet 142, is diffused, and is emitted to the outside.
Most of the light reflected on the surface 231 of the diffusion sheet 141 is reflected by the reflection plate 130 and enters the diffusion sheet 141 again.
The light reflected by the reflecting plate 130 is converted to yellowish light because a component with a short wavelength such as blue is absorbed by the reflecting plate 130. Light that has been interface-reflected by the surface 231 of the diffusion sheet 141 and repeatedly reflected by the reflector 130 is further absorbed by the reflector 130 with a component having a short wavelength such as blue, and becomes lighter yellowish.
The color temperature conversion filter described in the first embodiment as a whole in consideration of the proportion of light directly incident on the diffusion sheet 141 out of the light emitted from the white LED 121, the interface reflectance on the surface 231 of the diffusion sheet 141, and the like. The reflectance at which the reflecting plate 130 reflects light of a short wavelength such as blue is set so that the spectral characteristic is similar to the transmission characteristic of 150.

  The light emitted from the white LED 121 may not be directly incident on the diffusion sheet 141, and the white LED 121 may be disposed at a position where only the light reflected by the reflecting plate 130 is always incident at least once on the diffusion sheet 141. Or it is good also as a structure which arrange | positions white LED121 in the position where an incident angle is large in case the light which white LED121 emitted directly injects into the diffusion sheet 141, and raises the ratio which the interface which the light directly incident on the diffusion sheet 141 reflects. .

The lighting device 100 in this embodiment includes a first light emitting diode (LED element 212), a phosphor (mixed in the silicone resin 213), a second light emitting diode (LED element 222), and an optical component ( Reflector 130).
The first light emitting diode emits light having a first wavelength (about 460 nm) as a main wavelength.
The phosphor emits fluorescence having a second wavelength (about 560 nm) longer than the first wavelength as a main wavelength by light emitted from the first light emitting diode.
The second light emitting diode emits light having a third wavelength (approximately 635 nm) longer than the second wavelength as a main wavelength.
The optical component has a reflectance of the first wavelength lower than that of the second wavelength and the third wavelength, and the first light emitting diode, the phosphor, and the second light emitting diode Reflects light emitted by.

  According to the illumination device 100 in this embodiment, the optical component reflects the light emitted from the first light emitting diode, the phosphor, and the second light emitting diode, and the first wavelength component is kept low. Correlated color temperature Tc is low, deviation Duv from the black body locus is small, light emission efficiency is high, and light with excellent color rendering can be emitted.

In the illumination device 100 described above, instead of the color temperature conversion filter 150, the light component of the blue component is reflected on the reflection plate 130 that reflects the light from the LED to the emission surface side of the illumination device 100, and the green component and A material having a larger reflection characteristic than the light absorptance of the red component is used.
Thereby, the number of parts can be reduced and the assemblability is improved.

Embodiment 3 FIG.
Embodiment 3 will be described with reference to FIG.
In addition, about the part which is common in Embodiment 1 and Embodiment 2, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 10 is a bottom view and a side view BB cross-sectional view showing an example of the structure of the illumination device 100 according to this embodiment.
The color temperature conversion filter 150 is not provided between the two diffusion sheets 141 and 142 but at a position closer to the substrate 120 than the diffusion sheet 141.
The color temperature conversion filter 150 has an opening 151 at a position corresponding to the front surface of the red LED 122. Thus, the light emitted from the white LED 121 passes through the color temperature conversion filter 150 and then enters the diffusion sheet 141, whereas the light emitted from the red LED enters the diffusion sheet 141 as it is.

  Thus, instead of covering all the LEDs with the color temperature conversion filter 150, it is possible to mainly cover only the white LED 121 and not the red LED 122. Thereby, since the light emitted from the red LED 122 reaches the diffusion sheet 141 without being reflected or absorbed by the color temperature conversion filter 150, there is no loss and the light emission efficiency can be improved.

Embodiment 4 FIG.
The fourth embodiment will be described with reference to FIGS.
In addition, about the part which is common in Embodiment 1 and Embodiment 2, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 11 is a perspective view showing an example of the appearance of the illumination device 100 according to this embodiment.
The lighting device 100 is an LED bulb that includes an LED and a power supply circuit that lights the LED, and has a base portion 180 that can be connected to a general bulb socket. The lighting device 100 includes a base part 180, a frame 160, and a cover 190. The lighting device 100 has a light bulb shape as a whole.
The base part 180 (base) has a shape that fits into a socket for a light bulb, contacts an electrode in the socket, and inputs power from a power source such as a commercial power source.
The frame 160 (light bulb outer portion) has a cylindrical shape that spreads in a trumpet shape, and the side with a narrow diameter is connected to the base part 180 and the side with a wide diameter is connected to the cover 190. The frame 160 incorporates a substrate 120, a power supply circuit, and the like. The frame 160 is formed of a material having high thermal conductivity such as aluminum, for example, and releases heat inside the lighting device 100 to the outside.
The cover 190 has a shape in which a circular opening is provided in a hollow sphere and the periphery of the opening is slightly extended outward. The cover 190 is connected to the frame 160 at the opening and hermetically covers the substrate 120 and the power supply circuit.

FIG. 12 is an exploded perspective view showing an example of the internal structure of lighting apparatus 100 according to this embodiment.
Inside the lighting device 100 covered with the frame 160 and the cover 190, there are a power circuit 170, a substrate 120, a reflector 130, and the like.
The power supply circuit 170 converts the power input by the base unit 180 into power for lighting the LED.
On the substrate 120, for example, three white LEDs 121 and three red LEDs 122 are mounted. The ratio between the number of white LEDs 121 and the number of red LEDs 122 is not limited to this, and may be other ratios. The ratio between the number of white LEDs 121 and the red LEDs 122 is determined based on the set value of the color temperature of the light emitted from the lighting device 100.
The substrate 120 and the power supply circuit 170 are fixed to the frame 160 with screws or the like so that the generated heat is efficiently transmitted to the frame 160 and dissipated.

  The cover 190 is a color temperature conversion diffusion cover that diffuses and transmits light and has different transmittance depending on the wavelength of light. The cover 190 is formed, for example, by mixing a coloring material such as a pigment in acrylic, polycarbonate, glass, or the like. The cover 190 diffuses the light emitted from the white LED 121 and the red LED 122 to make the light emitted from the illumination device 100 uniform. The cover 190 transmits part of the light emitted by the white LED 121 and the red LED 122 and absorbs or reflects part of the light. The transmittance of the cover 190 varies depending on the wavelength of light, and has, for example, the characteristics shown in FIG.

  The light emitted from the white LED 121 and the light emitted from the red LED 122 are incident on the cover 190. The cover 190 diffuses the incident light and mixes the light emitted from the white LED 121 and the light emitted from the red LED 122. At the same time, the short wavelength component is cut. The lighting device 100 emits light diffused and transmitted by the cover 190.

  When the cover 190 cuts the short wavelength component, the light near the wavelength of 460 nm emitted from the LED element 212 of the white LED 121 is significantly cut. On the other hand, the light near the wavelength of 560 nm which is the main wavelength of the fluorescence emitted from the phosphor of the white LED 121 and the light emitted from the LED element 222 of the red LED 122 are not cut and are emitted with almost the same intensity. . Thereby, the peak intensity of the blue component becomes smaller than the peak intensity of the green component and the red component.

The lighting device 100 in this embodiment includes a base portion 180 and a power supply circuit 170.
The base portion 180 has a shape that fits into the socket for a light bulb, and inputs power from a power source.
The power supply circuit 170 converts the electric power input by the cap unit 180 into electric power to be supplied to the first light emitting diode (white LED 121) and the second light emitting diode (red LED 122).

  According to the lighting device 100 in this embodiment, since the light emitting diode can be turned on by connecting to an existing light bulb socket, there is no need for wiring work or the like, and illumination using a light emitting diode having a high energy saving effect is performed. Can be introduced. Further, not only the shape is the same as that of the light bulb, but also the color temperature of the emitted light can be set to the same level as that of the incandescent light bulb.

The illuminating device 100 (LED light bulb) described above emits the light of the LED through the cover 190 that has a larger blue component absorptivity than the green component and the red component, thereby causing the white LED 121 and the red LED to emit light. The color tone of the mixed color light with the LED 122 can be easily adjusted, the luminous efficiency and color rendering are high even at a color temperature of 5000K or less, and the chromaticity coordinate is the chromaticity coordinate of the same color temperature of the reference light (black body locus). An almost identical lighting device can be obtained.
In other words, a light source having a low color temperature having chromaticity coordinates on a black body locus, which is light of a color tone originally required for a lighting device, can be realized with high efficiency.

  By changing the transmission spectrum characteristics of the cover 190, the number of white LEDs 121 and the red LEDs 122, and the ratio of input power, an illumination device that emits light with a lower color temperature such as 3500K or 3000K can be easily configured. .

Embodiment 5 FIG.
A fifth embodiment will be described with reference to FIGS.
In addition, about the part which is common in Embodiment 1- Embodiment 3, the same code | symbol is attached | subjected and description is abbreviate | omitted.

FIG. 13 is an exploded perspective view showing an example of the internal structure of the illumination device 100 according to this embodiment.
The illumination device 100 further includes a color temperature conversion cover 195 in addition to the configuration described in the third embodiment.
The color temperature conversion cover 195 is a color temperature conversion diffusion cover that transmits and diffuses light with different transmittance depending on the wavelength of light. The color temperature conversion cover 195 has a substantially disk shape and is located between the reflection plate 130 and the cover 190. The color temperature conversion cover 195 transmits part of the light emitted from the white LED 121 and the red LED 122 and absorbs or reflects part of the light. The transmittance of the color temperature conversion cover 195 varies depending on the wavelength of light, and has, for example, the characteristics shown in FIG.
In contrast, the cover 190 is a transmissive diffusion cover that transmits and diffuses light with a constant transmittance regardless of the wavelength of light. The cover 190 has a smooth surface roughness on the outer surface, and interface reflection is relatively likely to occur.

Thus, by disposing the color temperature conversion cover 195 inside the cover 190 and making the cover 190 a translucent diffusion cover, it is possible to prevent the cover 190 from appearing yellowish when the light is turned off. You can make it look almost the same color.
Further, since the color temperature conversion cover 195 diffuses light and further diffuses light with the cover 190, the light emitted from the white LED 121 and the light emitted from the red LED 122 can be mixed better.

  FIG. 14 is an exploded perspective view showing another example of the internal structure of lighting apparatus 100 according to this embodiment.

  The color temperature conversion cover 195 is a hollow hemisphere. The color temperature conversion cover 195 covers only the white LED 121 and does not cover the red LED 122. Therefore, the color temperature conversion cover 195 transmits part of the light emitted by the white LED 121 and absorbs or reflects part of the light, but the light emitted by the red LED 122 is not affected by the color temperature conversion cover 195, The light enters the cover 190 as it is.

  As described above, instead of covering all the LEDs with the color temperature conversion cover 195, only the white LED 121 may be covered and the red LED 122 may not be covered. Thereby, the light emitted from the red LED 122 reaches the cover 190 without being reflected or absorbed at the interface by the color temperature conversion cover 195, so there is no loss and the light emission efficiency can be improved.

  DESCRIPTION OF SYMBOLS 100 Illumination device, 110 housing | casing, 120 board | substrate, 121 white LED, 122 red LED, 130 reflector, 141,142 diffusion sheet, 150 color temperature conversion filter, 151 opening part, 160 frame, 170 power supply circuit, 180 base part, 190 cover, 195 color temperature conversion cover, 211, 221 package, 212, 222 LED element, 213, 223 silicone resin, 231, 232 surface, 236, 237 back surface, 411-413 spectrum curve, 421-422 light distribution curve, 431 Transmittance curve, 441-444 chromaticity coordinates, 451 black body locus, 452 spectrum locus, 511 external light, 512, 522 interface reflected light, 513, 516, 523, 525, 527 diffused light, 514, 524 transmitted light, 515 , 526 Reflected light, 521 Shako.

Claims (8)

A first light emitting diode emitting light having a first wavelength as a dominant wavelength;
A phosphor that emits fluorescence having a second wavelength longer than the first wavelength as a main wavelength by light emitted from the first light emitting diode;
A second light emitting diode that emits light having a third wavelength longer than the second wavelength as a dominant wavelength;
The transmittance of the first wavelength is lower than the transmittance of the second wavelength and the third wavelength, and the light emitted from the first light emitting diode, the phosphor and the second light emitting diode is emitted. An illuminating device comprising: an optical component that transmits the light. A first light emitting diode emitting light having a first wavelength as a dominant wavelength;
A phosphor that emits fluorescence having a second wavelength longer than the first wavelength as a main wavelength by light emitted from the first light emitting diode;
A second light emitting diode that emits light having a third wavelength longer than the second wavelength as a dominant wavelength;
The transmittance of the first wavelength is lower than the transmittance of the second wavelength, and includes an optical component that transmits light emitted from the first light emitting diode and the phosphor. Lighting device. A first light emitting diode emitting light having a first wavelength as a dominant wavelength;
A phosphor that emits fluorescence having a second wavelength longer than the first wavelength as a main wavelength by light emitted from the first light emitting diode;
A second light emitting diode that emits light having a third wavelength longer than the second wavelength as a dominant wavelength;
The reflectance of the first wavelength is lower than the reflectance of the second wavelength and the third wavelength, and the light emitted from the first light emitting diode, the phosphor, and the second light emitting diode is emitted. An illuminating device comprising a reflecting optical component. The lighting device has a number of the first light emitting diodes greater than the number of the second light emitting diodes,
4. The lighting device according to claim 1, wherein the second light emitting diode has a light distribution characteristic that illuminates a wider area than a light distribution characteristic of the first light emitting diode. The lighting device has a number of the second light emitting diodes greater than the number of the first light emitting diodes,
The lighting device according to any one of claims 1 to 3, wherein the first light emitting diode has a light distribution characteristic that illuminates a wider area than a light distribution characteristic of the second light emitting diode. The lighting device further includes:
A diffusion sheet having an incident surface on which light transmitted or reflected by the optical component is incident and an exit surface that emits light obtained by diffusing the light incident from the incident surface with a finer surface roughness than the incident surface; The illumination device according to any one of claims 1 to 5, wherein:   The illumination device according to claim 1, wherein the optical component is a color temperature conversion filter or a reflector. The lighting device further includes:
Having a shape that fits into a socket for a light bulb, and a base part for inputting power from a power source;
8. The power supply circuit according to claim 1, further comprising: a power supply circuit that converts electric power input to the base portion into electric power supplied to the first light emitting diode and the second light emitting diode. 9. The lighting device described.

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