JP2010192829A - Light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light emitting device capable of improving a color mixing property to suppress color unevenness, and also improving optical output. <P>SOLUTION: The light emitting device includes a plurality of kind of LED chips 11 to 13 emitting light beams differing in main wavelengths from one another, a mounting substrate 20 having the plurality of kind of LED chips 11 to 13 mounted on one surface side, and a lens portion (transparent body) 30 covering the plurality of kind of LED chips 11 to 13 on the one surface side of the mounting substrate 20. The lens portion 30 is provided with many metal nanostructures 40 which have surface plasmons 50 excited with the light beams emitted by the respective LED chips 11 to 13 to cause surface plasmon resonance. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a light emitting device using a plurality of types of LED chips (light emitting diode chips) having different main wavelengths.

  Conventionally, as a white light source using an LED chip, a GaN-based LED chip that emits blue light and a phosphor that emits light of an emission color different from that of the LED chip when excited by light emitted from the LED chip ( For example, a light emitting device using a yellow phosphor or a red phosphor and a green phosphor (hereinafter referred to as a phosphor-type light emitting device), an LED chip whose emission color is red, and an LED whose emission color is green A light-emitting device using a chip and an LED chip whose emission color is blue (hereinafter referred to as a multi-chip type light-emitting device) has been researched and developed in various places (for example, see Patent Document 1).

  Here, the multi-chip type light emitting device has a feature that the control of chromaticity and color temperature is easier than the phosphor type light emitting device, but the deterioration rate of the LED chip is different, so the same chromaticity is obtained. In order to maintain, it is necessary to devise such as monitoring the light output of each color LED chip and performing feedback control.

  In addition, color unevenness is a problem common to both light emitting devices. In particular, in a multi-chip type light emitting device, color unevenness is likely to occur because a plurality of types of LED chips having different main wavelengths are spatially separated.

  Here, an LED chip that emits red light (R), an LED chip that emits green light (G), and an LED chip that emits blue light (B) are used as illumination devices using a light emitting device of a multi-chip system. There has been proposed an illuminating device including a light emitting unit having a light distribution lens made of glass that controls light distribution of light emitted from the light emitting unit.

However, in this type of illumination device, the refractive index of the medium is different for light R, G, B having different main wavelengths, so that the light R, G, B that has followed the same optical path in the glass as shown in FIG. However, the direction of refraction into the air is divided according to Snell's law. Here, when light R, G, B enters the interface between glass and air from the glass side through the same optical path, the incident angle is θ, the refraction angles are θ _R , θ _G , θ _B , and the light R, B in the glass. When the refractive indexes are n _R and n _B , the relationship of sin θ _B = n _B sin θ and the relationship of sin θ _R = n _R sin θ are established according to Snell's law. In glass, n _B > n _R. Therefore, θ _B > θ _R. Therefore, when the light from the light emitting unit is condensed using the light distribution lens, chromatic aberration is generated, and when viewed from the optical axis, as shown in FIG. There are a region (R + G + B) in which all of these overlap, a region (R + G, G + B) in which they overlap each other, and a region (R, G) in which they do not overlap, and color unevenness is observed.

  By the way, in the optical design of the illumination system, the geometric optical design using the ray tracing method is generally performed, but in the geometric optical design, the light advances due to refraction at the interface where the refractive index changes. It is premised on controlling the direction, and it is necessary to increase the thickness dimension of the light distribution lens, and there is a limit to the control range of the light traveling direction. Therefore, thinning of the lighting fixture which does not have color unevenness and is capable of narrow-angle light distribution is limited.

  On the other hand, conventionally, as a white light source used for an LED lighting apparatus or the like, a plurality of types of LED chips having different main wavelengths (for example, a red LED chip, a green LED chip, a blue LED chip) and the plurality of types of LEDs A mounting substrate having a chip mounted on one surface side, and a sealing portion made of a translucent sealing resin (for example, epoxy resin) that seals each LED chip on the one surface side of the mounting substrate, There has been proposed a multi-chip type light emitting device in which a light diffusing material (light dispersion member) made of glass beads having an average particle diameter of about 10 μm to 1 mm is contained in the stopper (see, for example, Patent Document 1).

JP 2002-280617 A

  By the way, in the light emitting device disclosed in Patent Document 1, since the emitted light from each LED chip is reflected and mixed by the light diffusing material in the sealing portion, the occurrence of color unevenness can be suppressed.

  However, in the case where the light diffusing material is contained in the translucent sealing resin as in the light emitting device disclosed in Patent Document 1, light loss due to the light diffusing material occurs, and the light output is reduced. End up.

  The present invention has been made in view of the above-described reasons, and an object of the present invention is to provide a light-emitting device that can improve color mixing, suppress the occurrence of uneven color, and improve light output.

  The invention of claim 1 includes a plurality of types of LED chips that emit light having different main wavelengths, a mounting substrate on which the plurality of types of LED chips are mounted on one surface side, and the one surface side of the mounting substrate on the one surface side. A transparent body that covers a plurality of types of LED chips, and the transparent body is provided with a plurality of metal nanostructures in which surface plasmons are excited by light emitted from each LED chip and surface plasmon resonance occurs. Features.

  According to the present invention, surface plasmon resonance is caused by light emitted from a plurality of types of LED chips having different main wavelengths, and surface plasmons are excited on the surface of a large number of transparent metal nanostructures covering each LED chip. Therefore, the color mixing property can be improved, the light emitted from each LED chip can be enhanced, the color mixing property can be improved, the occurrence of uneven color can be suppressed, and the light output can be improved.

  The invention of claim 2 is characterized in that, in the invention of claim 1, the metal nanostructure is formed of spherical metal nanoparticles and provided in the transparent body.

  According to the present invention, it is possible to prevent deterioration of the metal nanostructure due to adsorption of moisture and oxygen in the air, shape change of the metal nanostructure, aggregation, and the like.

  According to a third aspect of the present invention, in the first aspect of the invention, the metal nanostructure is made of spherical metal nanoparticles and is arranged on a light emitting surface of the transparent body.

  According to this invention, the metal nanostructure can be easily formed.

  The invention of claim 4 is characterized in that, in the invention of claim 1, the metal nanostructure is made of metal nanorods.

  According to this invention, compared with the case where the metal nanostructure is a metal nanoparticle, the effect of enhancing the light is strong and the light output can be increased. Further, according to the present invention, directivity control and control of the enhancement wavelength can be performed by controlling the aspect ratio, which is the ratio of the major axis to the minor axis of the metal nanorod.

  According to the first aspect of the present invention, the color mixing property can be improved, the occurrence of color unevenness can be suppressed, and the light output can be improved.

The light-emitting device of Embodiment 1 is shown, (a) is principal part schematic sectional drawing, (b) is principal part explanatory drawing. (A) shows a structural example for confirming surface plasmon resonance, (b) is a light intensity distribution diagram by surface plasmon resonance in the XZ section of (a), and (c) is a surface plasmon in the XY section of (a). It is a light intensity distribution map by resonance. It is a schematic sectional drawing which shows the other structural example of the light-emitting device same as the above, and is equivalent to the A-A 'cross section of Fig.1 (a). 6 is a schematic cross-sectional view of a light emitting device according to Embodiment 2. FIG. 6 is a schematic cross-sectional view of a light emitting device according to Embodiment 3. FIG. 6 is a schematic cross-sectional view of a light emitting device according to Embodiment 4. FIG. It is explanatory drawing of the cause of generation | occurrence | production of the color nonuniformity in a prior art example. It is explanatory drawing of the generation | occurrence | production cause of the color nonuniformity in the same as the above. It is sectional drawing.

(Embodiment 1)
As shown in FIG. 1, the light emitting device of this embodiment uses a plurality of types (here, three types) of LED chips 11, 12, and 13 having different main wavelengths, and emits light at a main wavelength of 650 nm. Red LED chip (red LED chip) 11, LED chip (green LED chip) 12 having a main wavelength of 550 nm and green emission color, and LED chip (blue LED chip) having a main wavelength of 450 nm and blue emission color ) 13 and a single rectangular plate-like mounting substrate 20 on which one or more LED chips 11 to 13 having different main wavelengths are mounted on one surface side, and each LED chip 11 to 11 on the one surface side of the mounting substrate 20. 13 and a lens portion 30 made of a translucent material covering a bonding wire (not shown) electrically connected to each LED chip 11 to 13, and each LED chip. By flowing a forward current to 11 to 13, it is possible to obtain white light as mixed light of red light, green light and blue light. Note that the planar shape of the mounting substrate 20 is not limited to a rectangular shape, and may be, for example, a triangular shape, a rhombus shape, a pentagonal shape, a hexagonal shape, or the like.

  The LED chips 11 to 13 are arranged in a horizontal line in the central portion on the one surface side of the mounting substrate 20 so as to be close to each other at equal intervals. The mounting substrate 20 is for supplying power to the LED chips 111 to 13. A conductor pattern (not shown) is formed. Here, the arrangement of the LED chips 11 to 13 is not particularly limited, and the centers of the three LED chips 11 to 13 are positions corresponding to the three vertices of the virtual equilateral triangle in a plan view. You may arrange.

  The lens unit 30 is formed in a hemispherical convex lens shape with a translucent material, and the lens unit 30 also serves as a sealing unit that seals the LED chips 11 to 13, but is formed with the translucent material. The lens unit 30 may be configured by a convex lens-shaped sealing unit that seals the LED chips 11 to 13 and a dome-shaped optical member that is formed of a light-transmitting material and covers the sealing unit. In addition, as these translucent materials, for example, epoxy resin, glass, silicone resin, polycarbonate resin, acrylic resin, etc. may be adopted, and the sealing portion and the optical member are formed of the same translucent material. Alternatively, they may be formed of different light-transmitting materials.

  By the way, in the light emitting device of the present embodiment, the lens unit 30 is provided with a number of metal nanostructures 40 that excite the surface plasmon 50 by the light emitted from the LED chips 11 to 13 and cause surface plasmon resonance. The lens unit 30 constitutes a transparent body provided with a large number of metal nanostructures 40. Here, the metal nanostructure 40 is composed of metal nanorods having a cross-sectional diameter orthogonal to the major axis direction of 200 nm or less, preferably 50 nm or less, and intersects the light emitting surface from the light emitting surface of the lens unit 30. It protrudes in the direction of In short, the metal nanostructure 40 is disposed in the vicinity of the interface between the lens unit 30 and a medium (air) in contact with the light emitting surface of the lens unit 30.

The surface plasmon 50 is a vibration mode of free electrons existing on the surface of the metal nanostructure 40 (a plasma mode that is localized on the surface of the metal nanostructure 40 and whose amplitude exponentially decays with the depth from the surface). An electron density wave (surface wave) that interacts with light. In essence, the surface plasmon 50 interacts directly with light and generates an enhanced electromagnetic field upon excitation. Here, the surface plasmon 50 is a negative value of the real part (ε ′ = n ² −k ² , where n is the refractive index and k is the extinction coefficient) of the metal material of the metal nanostructure 40. In the case of a material having a large absolute value (for example, Au or Ag), the interaction with light in the visible light region is strong. In the present embodiment, the metal nanostructure 40 is composed of metal nanorods. However, the metal nanostructure 40 may be composed of metal nanoparticles having a particle size of 200 nm or less, preferably 20 nm or less. By using Au or Ag as the metal material, the interaction between the surface plasmon 50 and the light in the visible light region is strengthened.

  Here, as a reference example, as shown in FIG. 2A, a metal nanorod (rod-like) having a short axis length (diameter) of 50 nm and a long axis length of 200 nm on the light extraction surface of a blue LED chip 13 having a dominant wavelength of 450 nm. In a structural model in which a metal nanostructure 40 made of metal nanoparticles is arranged, light in the vicinity of the metal nanostructure 40 due to surface plasmon resonance when light emitted from the blue LED chip 13 enters the metal nanostructure 40 About the intensity distribution (distribution of light amplitude, which corresponds to the distribution of electric field / magnetic field amplitude), it is called FDTD method (Finite-Difference Time-Domain method) or finite-difference time-domain method. 2 (b) and 2 (c) show the results of the electromagnetic field simulation using Here, in the structural model of FIG. 2A, the center position of the light emitting layer of the LED chip 13 is the origin of the XYZ orthogonal coordinates, and the medium between the light emitting layer and the metal nanostructure 40 is GaN (having a refractive index). 2.4) The medium around the LED chip 13 and the metal nanostructure 40 is air (refractive index is 1), the metal material of the metal nanostructure 40 is Ag, and light is emitted from the light emitting layer of the LED chip 13. The direction is the Z-axis direction. Here, FIG. 2B shows the light intensity distribution in the XZ section when Y = 0, and FIG. 2C shows the light intensity distribution in the XY section when Z = 0.3 μm. In FIGS. 2B and 2C, the magnitude of light intensity (arbitrary unit) is shown as a difference in color, which means that the phase is reversed between a positive value and a negative value. is doing.

  2B and 2C that the light intensity is locally enhanced in the vicinity of the metal nanostructure 40. FIG. In short, it can be seen from FIGS. 2B and 2C that the light from the LED chip 13 is enhanced by surface plasmon resonance. Here, in the structural model shown in FIG. 2A, the medium (that is, the medium through which light propagates) between the light emitting layer and the metal nanostructure 40 is GaN. The same phenomenon (enhancement of light due to surface plasmon resonance) occurs essentially as a material (glass, silicone resin, epoxy resin, polycarbonate resin, acrylic resin, etc.), and the distance between the light emitting layer and the metal nanostructure 40 The same phenomenon occurs regardless of. Further, in the light emitting device of this embodiment, the metal nanostructure 40 is configured by metal nanorods, but the metal nanostructure 40 is configured by spherical metal nanoparticles as in the light emitting device illustrated in FIG. Also good.

  By the way, in the light-emitting device of this embodiment, the surface plasmon 50 is excited when the light of the LED chips 11 to 13 enters the metal nanostructure 40, and light of a specific wavelength component is generated in a specific direction by the surface plasmon resonance. The light becomes stronger, and the incident light to the metal nanostructure 40 is transmitted along the surface of the metal nanostructure 40 without changing to reflected light. Here, the wavelength and traveling direction of light contributing to surface plasmon resonance can be controlled by the arrangement interval and shape of the metal nanostructures 40.

  Therefore, in order to improve the color mixing property by equalizing the phase distribution of the light of each main wavelength emitted from each LED chip 11 to 13, as shown in FIG. 1, a metal nanostructure 40 made of metal nanorods is used as a lens. A plurality of metal nanostructures 40 made of spherical metal nanoparticles are projected in a direction intersecting the light exit surface of the lens portion 30 as shown in FIG. In the example shown in the figure, it is desirable that the two are connected to each other on the light emitting surface of the lens unit 30. By arranging the metal nanostructures 40 as shown in FIGS. 1 and 4, directivity control (for example, , Declination light distribution control, etc.) can also be performed. However, it is easier to manufacture the light emitting device when the metal nanostructure 40 is a metal nanorod than when the spherical metal nanoparticles are arranged in a direction intersecting the light exit surface of the lens unit 30. In addition, as a method of arranging the metal nanostructure 40 on the lens unit 30, for example, using a stamp (mold) on which a fine pattern of nanometer order corresponding to the arrangement pattern of the metal nanostructure 40 is given in advance. A positive charging pattern is formed on the light emitting surface of the lens unit 30, and the negatively charged metal nanostructure 40 is supplied in a gas phase to thereby follow the electrostatic potential between the metal nanostructure 40 and the lens unit 30. The metal structure 40 may be moved and fixed, or a method called self-organization using the force acting between the particle surfaces may be adopted.

  The resonance wavelength (absorption peak wavelength) of the surface plasmon 50 described above is the type of metal material of the metal nanostructure 40 and the size of the metal nanostructure 40 (particle diameter, major axis length, minor axis length, aspect ratio = major axis). (Long / short axis length, etc.), presence / absence of a coating film on the metal nanostructure 40, and a dielectric constant of the coating film. In addition, the resonance wavelength changes as the volume average primary particle size and the volume average aggregate diameter depending on the adjustment conditions (formation conditions) and shape of the metal nanostructure 40 increase.

The resonance wavelength of the surface plasmon 50 can be predicted by the Mie scattering formula in the Mie theory. For example, when the resonance wavelength of the surface plasmon 50 when the metal material of the metal nanostructure 40 is Ag, Au, and Cu is about 400 nm, about 530 nm, and about 570 nm, respectively, the metal whose metal material is Au The resonance wavelength when the nanostructure 40 is coated with the SiO ₂ film is about 510 nm to 540 nm, and the resonance wavelength when the metal nanostructure 40 whose metal material is Au is coated with the TiO ₂ film is about 640 nm. . This is because the resonance wavelength of the surface plasmon 50 shifts to the long wavelength side (low photon energy side) as the dielectric constant of the medium in contact with the metal nanostructure 40 increases, and TiO ₂ is more in comparison with SiO ₂ . This is because the dielectric constant is high. Further, the resonance wavelength when the metal nanostructure 40 whose metal material is Ag is coated with a SiO ₂ film is about 425 nm. However, the resonance wavelength of the surface plasmon 50 shifts to the longer wavelength side as the particle size of the metal nanostructure 40 increases.

  Further, when the metal material of the metal nanorod constituting the metal nanostructure 40 is Au, the aspect ratio (= major axis length / minor axis length) of the metal nanorod is controlled to change from visible light to near infrared light ( At present, it is possible to cause surface plasmon resonance at an arbitrary specific wavelength up to 530 nm to 1100 nm), and if the metal material of the metal nanorod is Ag, surface plasmon resonance is generated on the short wavelength side compared to Au. It is possible to wake up. In addition, the metal nanorods having anisotropic particle shape can control the macro optical properties by controlling the orientation of the light exit surface of the lens unit 30, Compared to directivity control (light distribution control), this is advantageous. In addition, metal nanorods have a stronger light enhancement effect than spherical metal nanoparticles.

  In addition, as a formation method of the metal nanorod and the spherical metal nanoparticle constituting the metal nanostructure 40, a well-known formation method may be appropriately employed. For example, a CVD method, a metal chloride reduction / oxidation / nitridation method, and the like. Gas phase methods such as reduction in hydrogen, solvent deposition, epitaxial growth, gas deposition, laser ablation, metal vapor synthesis, and vacuum deposition on fluid oil), colloidal methods, hydrothermal synthesis, sol -Liquid phase methods such as gel method, neutralization decomposition method, hydrolysis method, chemical precipitation method, coprecipitation method, atomizing (spraying / solidification) method, reverse micelle method, emulsion method, recrystallization method, thermal decomposition method A solid phase method such as a firing method, a graphitization method, a thermal reduction method, or a pulverization method may be appropriately employed.

  In the present embodiment, if, for example, a surface-emitting LED chip is used as each of the LED chips 11 to 13, the radiation angle dependence of each radiated light intensity is approximated by a Lambert distribution. Therefore, if the radiated light intensity of each of the three types of LED chips 11, 12, 13 having different main wavelengths is uniform in the spherical region and the lens portion 30 is not provided with a plurality of metal nanostructures 40, the lens In the central part (top surface) where the three spherical regions overlap on the light exit surface of the unit 30, the emitted light (red light) from the red LED chip 11, the emitted light (green light) from the green LED chip 12, and the blue LED chip The radiated light (blue light) from 13 is mixed and desired white light is obtained, and the desired mixed color light cannot be obtained in the periphery where the three spherical regions do not overlap.

  On the other hand, in the light emitting device according to the present embodiment, surface plasmon resonance occurs in the lens unit 30 covering the plurality of types of LED chips 11 to 13 by exciting surface plasmons with light emitted from the LED chips 11 to 13. Since a large number of metal nanostructures 40 are provided, the surface plasmon 50 is excited on the surface of each metal nanostructure 40 by the light emitted from the LED chips 11 to 13, so that the surface plasmon resonance occurs. In addition, the light emitted from each of the LED chips 11 to 13 can be enhanced, the color mixing property can be improved, the occurrence of uneven color can be suppressed, and the light output can be improved. Here, in the light emitting device of the present embodiment, by making the size and arrangement of the metal nanostructures 40 random, the emission directions of the light of the respective main wavelengths from the LED chips 11 to 13 are easily aligned, and color mixing properties are achieved. (A solid line arrow in FIG. 1 indicates red light emitted from the LED chip 11, a broken line arrow indicates green light emitted from the LED chip 12, and an alternate long and short dash line arrow indicates that emitted from the LED chip 13.) Blue light, and the respective propagation directions are schematically shown). Here, in the light emitting device of the present embodiment, the metal nanostructure 40 made of, for example, metal nanorods and having a random size (the long axis length and the short axis length determining the aspect ratio are random) is provided on the light emitting surface of the lens unit 30. If arranged, the resonance wavelength at which surface plasmon resonance occurs becomes random, and the color mixing property is improved. Further, as shown in FIG. 3, if the metal nanostructures 40 having different sizes are arranged in a matrix and randomly arranged, the propagation directions of the light of the respective main wavelengths emitted from the light emitting surface of the lens unit 30 are easily aligned. The color mixing property is further improved.

  Moreover, in this embodiment, since the metal nanostructure 40 is comprised by the metal nanorod, compared with the case where the metal nanostructure 40 is a spherical metal nanoparticle, the enhancement effect is strong and high output of light output. Can be realized. Moreover, directivity control (for example, declination light distribution control) and control of the enhancement wavelength can be performed by controlling the aspect ratio of the metal nanorods.

  If the light emitting device of the present embodiment described above is used as a light source of a lighting fixture, the thickness dimension of the light distribution lens can be reduced, and the lighting fixture capable of narrow-angle light distribution without color unevenness can be achieved. .

(Embodiment 2)
The basic configuration of the light emitting device of the present embodiment is substantially the same as that of the first embodiment. As shown in FIG. 3, the metal nanostructure 40 is formed of spherical metal nanoparticles and provided in the lens unit 30. The only difference is that In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

  In the present embodiment, the metal nanostructure 40 made of metal nanoparticles is dispersed in the lens portion 30 made of a translucent material. Here, in order to provide the metal nanostructure 40 in the lens portion 30, for example, the lens is made of a translucent material (for example, silicone resin) in which the metal nanostructure 40 made of metal nanoparticles purified in advance is dispersed. The part 30 may be formed. Moreover, when the lens part 30 is comprised with the lens-shaped sealing part which seals the LED chips 11-13, and the optical member which covers the said sealing part, the metal nano consisting of the metal nanoparticle refine | purified previously. The optical member may be formed of a translucent material in which the structure 40 is dispersed, or a translucent material in which the metal nanostructure 40 is dispersed is applied to the surface side of the sealing portion. Also good. In addition, as a method of forming the metal nanostructure 40 in the lens unit 30, for example, a negative ion implantation method may be employed, and in this case, space controllability in the depth direction can be improved.

  In the light emitting device of the present embodiment described above, it is possible to prevent deterioration of the metal nanostructure 40 due to adsorption of moisture and oxygen in the air, shape change of the metal nanostructure 40, fusion, aggregation, and the like. it can.

(Embodiment 3)
The basic configuration of the light emitting device of the present embodiment is substantially the same as that of the first embodiment, and the mounting substrate 20 is formed with a housing recess in which the LED chips 11 to 13 and the lens unit 30 are housed. The difference is that the metal nanostructure 40 is provided on the light emitting surface of the glass substrate 60 which is airtightly fixed to the mounting substrate 20 so as to close the storage recess 20. In short, in this embodiment, the glass substrate 60 constitutes a transparent body provided with the metal structure 40. Here, a reflection film that reflects light from the LED chips 11 to 13 is appropriately provided on the inner surface of the housing recess in the mounting substrate 20. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  By the way, in each above-mentioned embodiment, the red LED chip 11, the green LED chip 12, and the blue LED chip 13 are provided as a plurality of types of LED chips 11 to 13 having different main wavelengths, and white light is obtained as desired mixed color light. However, the combination and the number of the main wavelengths of the LED chips constituting the light emitting device are not particularly limited, and may be set as appropriate according to the desired mixed color light.

  Moreover, when the linear expansion coefficient difference between each LED chip 11-13 and the mounting substrate 20 is relatively large, each LED chip 11-13 is replaced with the linear expansion coefficient between each LED chip 11-13 and the mounting substrate 20. You may make it mount in the mounting board | substrate 20 through the submount member which relieve | moderates the stress which acts on each LED chip 11-13 resulting from a difference. Here, one submount member may be provided for each of the LED chips 11 to 13, but if only one submount member is provided for the plurality of types of LED chips 11 to 13, the number of parts can be reduced. This is advantageous in terms of downsizing the entire light emitting device.

11 LED chip (red LED chip)
12 LED chip (green LED chip)
13 LED chip (blue LED chip)
20 Mounting board 30 Lens part (transparent body)
40 Metal nanostructure 50 Surface plasmon 60 Glass substrate (transparent)

Claims (4)

  A plurality of types of LED chips that emit light having different main wavelengths, a mounting substrate on which the plurality of types of LED chips are mounted on one surface side, and the plurality of types of LED chips covered on the one surface side of the mounting substrate A light emitting device comprising: a transparent body, and a plurality of metal nanostructures in which surface plasmon resonance is caused by excitation of surface plasmons by light emitted from each LED chip.   The light emitting device according to claim 1, wherein the metal nanostructure is formed of spherical metal nanoparticles and is provided in the transparent body.   The light emitting device according to claim 1, wherein the metal nanostructure is made of spherical metal nanoparticles and disposed on a light emitting surface of the transparent body.   The light emitting device according to claim 1, wherein the metal nanostructure is made of a metal nanorod.