JP2007214603A - Led lamp and lamp unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED lamp which is good in color reproducibility and also high in emission efficiency. <P>SOLUTION: The LED lamp 100 includes: a blue LED element 11; a red LED element 12; and a phosphor 13 excited by the blue LED element 11, for emitting emission spectra which compensate the emission intensity of the range of wavelengths between the blue range of wavelengths emitted by the blue LED element 11 and the red range of wavelengths emitted by the red LED element 12. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an LED lamp and a lamp unit, and more particularly to a white light emitting LED lamp.

  A light-emitting diode element (hereinafter referred to as an “LED element”) is a semiconductor element that is small, efficient, and emits brightly colored light, and has an excellent monochromatic peak. When emitting white light using an LED element, for example, it is necessary to arrange a red LED element, a green LED element, and a blue LED element in close proximity to perform diffusion color mixing, but each LED element has an excellent monochromatic peak. Therefore, uneven color tends to occur. That is, if the light emission from each LED element is not uniform and color mixing is not successful, white light emission with uneven color will occur. In order to solve such a problem of color unevenness, a technique for obtaining white light emission by combining a blue LED element and a yellow phosphor has been developed (for example, see Patent Document 1).

According to the technique disclosed in this publication, white light emission is obtained by light emission from a blue LED element and light emission from a yellow phosphor that is excited by the light emission and emits yellow light. In this technique, since white light emission is obtained using only one type of LED element, the problem of color unevenness that occurs when white light emission is obtained by bringing a plurality of types of LED elements close to each other can be solved.
Japanese Patent Laid-Open No. 10-242513

  Conventionally, since LED elements have been mainly applied as display elements, there has been little research and development in the case of using LED elements as illumination lamps. When using an LED element as a display element, it is only necessary to consider the characteristics of the color of light emitted from the self-emission emitted from the LED element, but when using it as a lamp, the color rendering property when illuminating an object is also a problem. It is necessary to. The fact is that LED lamps that have been studied up to the optimization of color rendering have not been developed yet.

  Although the LED element disclosed in the above publication can surely emit white light, the present inventor has found that there is the following problem when the LED element is used as a lamp. Since the conventional LED element produces a white emission color by the light emission of the blue LED element and the light emission of the yellow phosphor, the light emission spectrum of 600 nm or more which becomes a red component is insufficient. When the emission spectrum (red component) of 600 nm or more is insufficient, there arises a problem that red reproduction becomes low when applied to illumination or a backlight. Furthermore, since the red component is insufficient, it is difficult to construct a white light emitting LED element having a relatively low correlated color temperature. According to the results of investigation by the inventors of the present application, the average color rendering index Ra of the conventional white LED is inferior in red reproducibility even in the case of a light color having a high correlated color temperature that requires a small amount of red emission spectrum component. It is difficult to influence and exceed a value of about 85. When evaluated with the value of the special color rendering index R9 indicating the appearance of red color, the poor red reproducibility appears clearly, and the conventional white LED R9 shows only a low value in the vicinity of about 50.

  In addition, the inventor of the present application also examined a configuration in which a red phosphor is further added to the configuration of the LED element disclosed in the above publication to supplement an emission spectrum of 600 nm or more. However, in this configuration, the red phosphor is excited by the light emission of the blue LED to emit red light, so that the energy conversion efficiency is very poor. In other words, using blue to make red means that the conversion wavelength is large, so that the energy conversion efficiency is greatly reduced according to Stokes' law. Therefore, since the luminous efficiency of the LED lamp becomes extremely low, a configuration using a red phosphor is not practical.

  The present invention has been made in view of such various points, and a main object thereof is to provide an LED lamp having high color reproducibility and high luminous efficiency.

  A first LED lamp according to the present invention includes a blue light emitting LED element, a red light emitting LED element, a phosphor excited by the blue light emitting LED element, and a blue wavelength band emitted by the blue light emitting LED element; An LED lamp including a phosphor that emits an emission spectrum that compensates for emission intensity in a wavelength band between the red wavelength band emitted by the red light emitting LED element, and the correlated color temperature of the LED lamp is 5000 K or more. When the reference light source for color rendering evaluation is synthetic daylight, the peak wavelength of the blue light emitting LED element is in the range of 450 nm to 460 nm, and the peak wavelength of the red light emitting LED element is 600 nm or more, The emission peak wavelength of the phosphor is in the range of 520 nm to 545 nm.

  A second LED lamp according to the present invention is a blue light emitting LED element, a red light emitting LED element, a phosphor excited by the blue light emitting LED element, and a blue wavelength band emitted by the blue light emitting LED element; An LED lamp including a phosphor that emits an emission spectrum that compensates for emission intensity in a wavelength band between the red wavelength band emitted by the red light emitting LED element, and the correlated color temperature of the LED lamp is less than 5000K When the reference light source for color rendering evaluation is black body radiation, the peak wavelength of the blue light emitting LED element is in the range of 450 nm to 460 nm, and the peak wavelength of the red light emitting LED element is in the range of 615 nm to 650 nm. The emission peak wavelength of the phosphor is in the range of 545 nm to 560 nm.

  In one embodiment, the phosphor is a yellow light emitting phosphor that emits yellow light when excited by the blue light emitting LED element.

  In one embodiment, the yellow light emitting phosphor is a YAG phosphor or a phosphor having a Mn emission center.

  In one embodiment, the peak wavelength of the red light emitting LED element is in a range of 610 nm to 630 nm, and a special color rendering evaluation is performed rather than a color gamut area ratio Ga composed of R1 to R8 that are average color rendering indexes. The color gamut area ratio Ga4 composed of the numbers R9 to R12 is high.

  In one embodiment, there is further provided emission intensity adjusting means for adjusting the emission intensity of the red light emitting LED element.

  In one embodiment, the light emission intensity adjusting means is a variable resistor.

  In one embodiment, the blue light-emitting LED element, the red light-emitting LED element, and the phosphor are configured as an integral element.

  In one embodiment, the light emitting portion of the blue light emitting LED element and the light emitting portion of the red light emitting LED element are provided in one chip.

  In one embodiment, the blue light-emitting LED element and the LED element including the phosphor and the red light-emitting LED element are clustered.

  A lamp unit of the present invention includes the LED lamp according to any one of the above, and a power supply unit that supplies power to the LED lamp.

  In one embodiment, a reflection plate that reflects light emitted from the LED lamp is further provided.

  According to the LED lamp of the present invention, since the red light emitting LED element is provided, it is possible to introduce an emission spectrum of 600 nm or more, which is insufficient in white light emission by the conventional LED element, without reducing the luminous efficiency of the lamp. it can. For this reason, it is possible to provide an LED lamp capable of emitting white light with good color reproducibility and high luminous efficiency.

  The peak wavelength of the blue light emitting LED element is in the range of 450 nm to 470 nm, the peak wavelength of the red light emitting LED element is in the range of 610 nm to 630 nm, and the emission peak wavelength of the phosphor is in the range of 520 nm to 560 nm. In this case, an LED lamp having excellent color reproducibility can be realized. Furthermore, when the light emission intensity adjusting means for adjusting the light emission intensity of the red light emitting LED element is further provided, the light intensity of the red light emitting LED element can be adjusted, and therefore a light color variable LED lamp is provided. Can do.

  According to the LED lamp of the present invention, since the red light emitting LED element is provided, it is possible to provide an LED lamp capable of emitting white light with good color reproducibility and high luminous efficiency. Moreover, when the light emission intensity adjusting means for adjusting the light emission intensity of the red light emitting LED element is further provided, the light intensity of the red light emitting LED element can be adjusted. Can do.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, components having substantially the same function are denoted by the same reference numerals for the sake of simplicity.
(Embodiment 1)
FIG. 1 schematically shows the configuration of an LED lamp 100 according to the present embodiment. The LED lamp 100 includes a blue light emitting LED element 11, a red light emitting LED element 12, and a phosphor 13 that is excited by the blue light emitting LED element 11 and emits light. The blue light emitting LED element 11 is, for example, a GaN-based blue LED chip, and the red light emitting LED element 12 is, for example, an AlInGaP-based, GaAsP-based, or GaAlAs-based red LED chip. The GaN blue LED chip in this embodiment is a blue light emitting LED bare chip having a light emitting layer of GaN material, and the red LED chip is a red light emitting LED having a light emitting layer of AlInGaP, GaAsP, or GaAlAs material. It is a bare chip. The light emitting layer made of such a material becomes a light emitting portion of the LED.

  The phosphor 13 has a light emission intensity in a wavelength band between a blue wavelength band emitted from the blue light emitting LED element (blue LED chip) 11 and a red wavelength band emitted from the red light emitting LED element (red LED chip) 12. The supplementary emission spectrum is emitted. The phosphor 13 is, for example, a phosphor that is excited by the blue LED chip 11 to emit any color in the range of green to yellow, and is preferably a yellow light-emitting phosphor or a green light-emitting phosphor. Note that the light emission of the phosphor 13 is not limited to fluorescence but may be phosphorescence.

  FIG. 2 schematically shows the spectral distribution (emission spectrum distribution) of the LED lamp 100, where the wavelength is on the horizontal axis and the emission intensity is on the vertical axis. As shown in FIG. 2, the emission spectrum distribution of the LED 100 includes a blue emission spectrum (B) 21 emitted from the blue LED chip 11 and a green to orange color of the phosphor 13 excited and emitted by the blue LED chip 11. The emission spectrum (G−Y) 22 of any color in the range (for example, yellow) and the red emission spectrum (R) 23 emitted from the red LED chip 12 are included.

  As shown in FIG. 2, the spectral distribution of the LED lamp 100 includes the emission spectrum 23 of the red component in addition to the emission spectra 21 and 22. White light emission supplemented with the above emission spectrum can be performed. Since the red light emission spectrum 23 is not a component that is excited by the blue LED chip 11 and emits light from the phosphor, but is a component that emits light from the red LED chip 12, the light emission efficiency of the lamp does not decrease. That is, when the red light emission spectrum is generated by using the light emitted from the blue LED chip 11, the light emission efficiency of the lamp is remarkably lowered according to Stokes' law because the conversion wavelength from blue to red is large. On the other hand, in the lamp 100, since the red emission spectrum 23 is directly generated from the red LED chip 12, a white system with good color reproducibility that compensates for the red component without lowering the luminous efficiency of the lamp. Can emit light.

  In addition, when the emission spectra 21, 22 and 23 shown in FIG. 2 are generated directly from the LED chip, each LED chip has a monochromatic peak, and thus emits uniform white light. As described above, it is difficult to cause diffusion color mixing, and hence color unevenness occurs. In the LED lamp 100 of the present embodiment, in order to supplement the emission intensity of the emission spectrum located between the blue emission spectrum 21 of the blue LED chip 11 and the red emission spectrum 23 of the red LED chip 12, the blue LED chip 11 An emission spectrum 22 from the excited phosphor 13 is used. For this reason, it is easier to cause diffusion color mixing than when each of the emission spectra 21, 22, and 23 is directly generated from each LED chip, and as a result, white light emission that prevents and suppresses color unevenness is performed. Is possible.

  The blue LED chip 11, the phosphor 13 and the red LED chip 12 can be characterized by the emission peak wavelengths of the emission spectra 21, 22 and 23 that emit light, respectively. The blue LED chip 11 has an emission peak wavelength of 500 nm or less, for example, and the red LED chip 12 has an emission peak wavelength of 600 nm or more, for example. For example, a blue-green LED chip having a light emission peak wavelength of 540 nm or less can be used as the blue LED chip 11. In this specification, “blue LED chip (blue light emitting LED element)” includes “blue-green LED chip (blue green light emitting LED element)”. When a blue-green LED chip is used, a phosphor that emits light when excited by the blue-green LED chip may be used.

  The phosphor 13 has the emission peak wavelength of the phosphor between the emission peak wavelength of the blue LED chip 11 and the emission peak wavelength of the red LED chip 12. When the phosphor 13 is a yellow light emitting phosphor, the phosphor 13 has an emission peak wavelength, for example, between 540 and 590 nm, preferably between 550 and 590 nm. In addition, when the fluorescent substance 13 is a green light emission fluorescent substance, it has a light emission peak wavelength, for example between 480-560 nm, Preferably it is between 500-560 nm.

  As shown in FIG. 3, when the emission spectrum 22 is broad, for example, a clear emission peak may not necessarily exist between the emission spectra 21 (B) and 23 (R). When there is no clear emission peak wavelength in the phosphor 13, the phosphor 13 emits light assuming a virtual emission peak wavelength in a region located between the emission spectra 21 (B) and 23 (R). The spectrum may be characterized. In this case, the virtual emission peak wavelength can be set between the emission peak wavelengths of the emission spectra 21 (B) and 23 (R) (for example, the midpoint), for example.

  Refer to FIG. 1 again. In the white light emitting LED lamp 100 shown in FIG. 1, a blue LED chip 11, a red LED chip 12, and a phosphor 13 are formed as an integral element. More specifically, the blue LED chip 11 and the red LED chip 12 are both disposed on a plate-like (or cup-shaped) pedestal 17 formed as a part of the lead frame 14, and the blue LED chip 11. A phosphor 13 is formed on a base (pedestal) 17 so as to cover the red LED chip 12. Since the phosphor 13 only needs to be configured to emit light by the blue LED chip 11, the phosphor 13 may be configured to cover a part of the blue LED chip 11 and the red LED chip 12. The structure which is not covered may be sufficient.

  The lower end (lower terminal) of the blue LED chip 11 is disposed so as to be in contact with the base 17 and is electrically connected to the lead 14 a. The upper end (upper terminal) of the blue LED chip 11 is connected via the bonding wire 15. And electrically connected to the lead 14b. On the other hand, the lower end of the red LED chip 12 is also arranged so as to be in contact with the base 17 and is electrically connected to the lead 14a. The upper end of the red LED chip 12 is electrically connected to the lead 14c via the bonding wire 15. ing.

  In the present embodiment, an example in which an anode and a cathode that are electrodes of an LED are provided above and below the LED bare chip has been described. However, the present invention is not limited thereto, and the anode and the cathode may be provided on one side of the LED bare chip. Good. The LED bare chip can be produced by a known method, and can be obtained, for example, by growing a light emitting layer of an LED on a substrate. In this embodiment, the LED chip is wire-bonded for electrical connection. However, the present invention is not limited to this, and the LED chip may be flip-chip mounted. In this case, the bonding wire 15 can be omitted.

  The lead frame 14 is electrically connected to an external circuit (for example, a lighting circuit) (not shown). When power is supplied to the lead frame 14 to operate the blue LED chip 11 and the red LED chip 12, a red component is generated. The white light supplemented with light is emitted from the lamp 100. Further, the brightness of the lamp 100 can be controlled by adjusting the power supplied to the lead frame 14.

  A part 17 on which the blue LED chip 11 and the red LED chip 12 are arranged, a bonding wire 15 and a part of the lead frame 14 are encapsulated by a shell-like transparent resin part 16, and the transparent resin part 16 is, for example, It is made of epoxy resin or silicone resin. The shape of the transparent resin portion 16 is not limited to a cannonball shape, and may be a shape such as an SMD (surface mount device) chip type (a rectangular parallelepiped type), for example.

  In the integrated element type (one element type) LED lamp 100 shown in FIG. 1, the common lead 14a is used for the blue LED chip 11 and the red LED chip 12, and the blue LED chip 11 and the red LED chip 12 are shared. The blue LED chip 11 and the red LED chip 12 can be thermally coupled to each other. When both (11 and 12) are thermally coupled, they can be used at substantially the same temperature, so that it is possible to simplify the control of the element temperature characteristics. That is, when the blue LED chip 11 and the red LED chip 12 are arranged and operated on separate bases using four leads without using the common lead 14a, a semiconductor element is used. Since certain LED chips 11 and 12 have temperature dependency in their operation, it is necessary to control the element temperature characteristics of each of the blue LED chip 11 and the red LED chip 12. The temperature compensation of the operation can be easily performed by thermally coupling the LED chip 12 on the common base 17. Further, the configuration shown in FIG. 1 can reduce the number of leads (drawing leads) than the configuration using four leads, so that the manufacturing cost of the lamp can be reduced.

  Note that the number of leads of the lead frame 14 is not limited to three when one is used as the common lead 14a, but may be four in a configuration in which the common lead 14a is not used. In addition, if the forward current directions of the blue LED chip 11 and the red LED chip 12 are made the same, and they are electrically connected in series, the number of leads can be reduced to the minimum of two. is there.

  Further, since the LED lamp 100 is an integral element type, the size of the lamp can be made relatively small. Further, since the blue LED chip 11 and the red LED chip 12 are both mounted on the base 17 and the phosphor 13 is formed thereon, the light emitted from the blue LED chip 11 and the red LED chip 12 is fluorescent. The body 13 can scatter and diffuse. For this reason, the mixed light unevenness at the time of mixed light illumination can be reduced more effectively. That is, even when the light emission of the blue LED chip 11 and the light emission of the red LED chip 12 are mixed, a certain amount of color mixing unevenness occurs. However, in the LED lamp 100, the light emission from each LED chip passes through the phosphor 13. In this case, the light is scattered and diffused to be mixed, so that white light with reduced mixed color unevenness is obtained. Further, for the purpose of reducing uneven color mixing, for example, the surface of the transparent resin portion 16 can be made uneven so as to be further scattered and diffused.

  FIG. 4 shows an example of an actual emission spectrum distribution in the LED lamp 100. As can be seen from FIG. 4, the emission spectrum 21 of the blue LED chip 11 (emission peak wavelength: 460 nm, peak emission intensity: about 40) and the emission spectrum 22 of the yellow emission phosphor 13 (emission peak wavelength: 570 nm, peak emission intensity: In addition to about 20), the emission spectrum 23 of the red LED chip 12 (emission peak wavelength: 610 nm, peak emission intensity: about 100) is included. For this reason, according to the LED lamp 100, it is possible to compensate for the spectral power of red light emission that is insufficient when the phosphor is excited by the blue LED chip in the prior art.

  Further, since the spectrum power of the red light emission is supplemented by the light emission of the red LED chip 12, an LED lamp having higher light emission efficiency than the case where the red light emission phosphor supplements the spectrum power of the same red light emission. Can be provided. As described above, the emission peak wavelength of the red LED chip 12 may be 580 nm or more. However, the color reproduction characteristic (color reproducibility) that makes the color appear vividly is that the emission wavelength peak of the red LED chip 12 is 600 nm or more. Then, the stimulation purity for the L cones of the photoreceptor cells (the photoreceptor cells responding to the stimulus corresponding to red) is increased, so that it becomes particularly excellent. For this reason, it is preferable to set the emission peak wavelength to 600 nm or more.

  In addition, at present, there is no LED element phosphor (red light emitting phosphor) that emits an emission spectrum exceeding 600 nm with high efficiency, and a relatively inexpensive red LED chip 12 (GaAsP type). It is also very advantageous to supplement the red component with a GaAlAs red LED chip). Of course, an AlInGaP-based LED chip that is relatively expensive but has higher luminous efficiency may be used. Further, unlike the emission spectrum of the phosphor, the emission spectrum of the red LED chip 12 is narrow, so that only the red component that is insufficient in the conventional configuration can be introduced easily.

  In the LED lamp 100 of the present embodiment, the red emission spectrum power is given by the light emission of the red LED chip 12, so that the red emission spectrum power can be electrically controlled. Therefore, it is possible to easily adjust the intensity of the red emission spectrum, and as a result, it is possible to provide a color temperature variable light source with a simple configuration. That is, since the emission intensity of the yellow light emitting phosphor 13 basically correlates with the emission intensity of the blue LED chip 11 that is the excitation source, the emission intensity of the blue LED chip 11 and the emission intensity of the red LED chip 12 are set. As a result, an arbitrary light color can be obtained.

  FIGS. 5A to 5D show changes in the spectral distribution of the LED lamp 100 for explaining light color variation. The intensity | strength of the red emission spectrum 23 is so high that it goes to (d) from Fig.5 (a). As the intensity of the red emission spectrum 23 increases, the correlated color temperature of the LED lamp 100 decreases. That is, the light color of the LED lamp 100 can be arbitrarily changed by adjusting the intensity of the red emission spectrum 23. Therefore, for example, light colors having various correlated color temperatures such as daylight color, day white color, white color, warm white color, and light bulb color can be obtained.

  The light color variable LED lamp can be realized, for example, by making the LED lamp 100 of the present embodiment have the circuit configuration shown in FIG. The circuit 200 illustrated in FIG. 6 includes a blue LED chip 11, a light emission intensity adjusting unit (light emission intensity controller) 11 a that adjusts the light emission intensity of the blue LED chip 11, a red LED chip 12, and a light emission of the red LED chip 12. And a light emission intensity adjusting means (light emission intensity adjuster) 12a for adjusting the intensity. In the configuration shown in FIG. 6, a variable resistor is used as the light emission intensity adjusting means. According to this configuration, the light emission intensity ratio between the blue LED chip 11 and the red LED chip 12 can be adjusted, so that an arbitrary light color can be emitted. Furthermore, the brightness of the lamp can be easily adjusted.

  Since the correlated color temperature of the emission color can be changed by changing the emission intensity ratio of the blue LED chip 11 and the red LED chip 12, the emission intensity adjusting means 11a connected to the blue LED chip 11 is simply used. Even if a variable resistor is used only for the light emission intensity adjusting means 12a connected to the red LED chip 12 by using a fixed resistor, a light color variable LED lamp can be realized. The light emission intensity adjusting means is not limited to variable resistance, means for switching fixed resistance, means for using ladder resistance, means for frequency control, means for time-division lighting, means for changing the number of connected LED elements serving as loads Alternatively, means for switching the connection method can be used. In addition, if the light emission intensity ratio of the blue LED chip 11 and the red LED chip 12 is changed, a light color variable LED lamp can be realized. Therefore, the light emission intensity of the red LED chip 12 is fixed and the light emission of the blue LED chip 11 is performed. You may make it the structure which changes intensity | strength.

  FIG. 7 shows the chromaticity of the LED lamp 100 of this embodiment. With reference to FIG. 7, the range in which the light color of the LED lamp 100 of the present embodiment can be varied when a yellow light emitting phosphor is used as the phosphor 13 will be described. The yellow light emitting phosphor 13 is, for example, a YAG phosphor or a phosphor having a Mn emission center. As described above, when a YAG phosphor is used as the yellow light-emitting phosphor 13, the case where a in the following formula is small and b is large is preferable from the viewpoint of increasing the light emission efficiency because the phosphor is more green.

_{YAG = (Y 1-a,} Gd a) 3 (Al 1-b, Ga b) 5 O 12: Ce
A region 41 in FIG. 7 is the chromaticity of the blue LED chip 11, and the blue LED chip 11 has a light emission peak in the vicinity of 440 to 480 nm. A curve 42 is the chromaticity of the yellow light emitting phosphor (YAG phosphor) 13. The smaller a and the larger b in the composition of the YAG phosphor 13, the larger y and the smaller x on the chromaticity coordinates in FIG. Since the YAG phosphor 13 has an excitation spectrum peak in the vicinity of 440 to 480 nm, it is excited with high efficiency by the blue LED chip 11 whose region 41 has a range of emitted light color.

  The chromaticity in a range 45 surrounded by the region 41 and the curve 42 is a theoretical chromaticity range that can be realized by the blue LED chip 11 and the yellow light emitting phosphor (YAG phosphor) 13. However, since the output of the blue LED chip 11 itself, which is the excitation source, decreases as the emitted light color approaches the curve 42 even within the range 45, in practice, the LED lamp emits light with high efficiency. In this case, it is preferable to set a range in which the color temperature can be varied in a chromaticity range located between the region 41 and the curve 42 in the range 45. The chromaticity range 44 of the red LED chip 12 to be mixed with the white light emission chromaticity in such a range is in the vicinity of 600 nm from the viewpoint of color rendering. Therefore, in order to prevent the mixed light from leaving the black body radiation locus 30 in a wide range of correlated color temperatures, the chromaticity of white light emitted by the blue LED chip 11 and the yellow light emitting phosphor 13 is black body. It is desirable to be within a range 43 that is located above the radiation locus 30 and has a high correlated color temperature.

  As a result, in the chromaticity range surrounded by the chromaticity of the white light emission within the range 43 and the chromaticity of the red LED chip 12 within the range 44 (that is, the region between the line 31 and the line 32 in the figure). An LED lamp that can vary the correlated color temperature can be realized. In other words, the emission color conforming to the chromaticity range of the light source color of the fluorescent lamp specified by JIS and CIE (International Lighting Commission) (JIS: daylight color, day white, white, warm white, light bulb color. CIE; Daylight, Cool) white, white, and warm white) can be obtained, and in addition, a light-color-variable LED lamp that can also have a chromaticity in a region connecting the chromaticity ranges of the emission colors can be realized. A line 33 in the figure shows an example in which the chromaticity of the LED lamp 100 of the present embodiment is changed. That is, an example is shown in which the correlated color temperature can be greatly changed in a state closer to the blackbody radiation locus 30.

  In the example shown in FIG. 7, when the emission peak wavelength of the red LED chip 12 is set to 630 nm or less, the light color change locus follows the black body radiation locus. The light color in the vicinity of the radiation locus 30 can be changed. As a result, the average color rendering index can be increased.

  If it is intended to be used as a low color temperature light source without aiming at changing the correlated color temperature in a wide range, the chromaticity of white light emission in the range 43 by the blue LED chip 11 and the yellow light emitting phosphor 13 is used. The range surrounded by the chromaticity of the red LED chip 44 is not limited to the region between the line 31 and the line 32, and may be appropriately determined within the range 45.

  In the above embodiment, the case where a yellow light emitting phosphor is used as the phosphor 13 has been described. However, instead of the yellow light emitting phosphor, a green light emitting phosphor that is excited by the blue LED chip 11 and emits green light is used. Is also possible. The green light emitting phosphor has an emission peak wavelength of, for example, 480 to 560 nm. As the green light emitting phosphor, for example, at least one of YAG phosphor or Tb, Ce, Eu, and Mn is used. A doped phosphor can be used as the emission center. In order to improve color rendering properties as illumination light, it is possible to use a plurality of types of phosphors having different emission peak wavelengths. At present, there is no LED element that emits light with high efficiency in the vicinity of 555 nm, which has the highest luminous efficiency. Therefore, supplementing the light emission in the vicinity with light emitted from a phosphor has great significance. Moreover, although the case where the inorganic fluorescent substance was used was shown in the said embodiment, it replaced with an inorganic fluorescent substance and you may use the organic fluorescent substance which has the same light emission peak. This is because, with the development of organic EL, practical organic phosphors have recently been researched and developed, so that not only inorganic phosphors but also organic phosphors are being used.

  Similar to the yellow light-emitting phosphor, the light emission intensity of the green light-emitting phosphor basically correlates with the light emission intensity of the blue LED chip 11 that is the excitation source, so the light emission intensity of the blue LED chip 11 and the red LED chip 12 An arbitrary light color can be obtained simply by setting the emission intensity. Therefore, even when a green light emitting phosphor is used, a light color variable LED illumination light source with a simple configuration can be realized.

  Nowadays, it is a fact that a high-efficiency green light-emitting LED element having an emission spectrum in a band near 555 nm, which has the highest human relative visual acuity, does not exist industrially at a practical level. Achieving high efficiency by light emission from the body has great advantages.

  Further, in the case of a configuration using a green light emitting phosphor, the emission spectra of the blue LED chip 11, the green light emitting phosphor 13, and the red LED chip 12 are concentrated in a relatively narrow range of R, G, and B. It becomes possible to make it. For this reason, for example, a light source showing a vivid color reproduction characteristic with a large color gamut area ratio, such as a three-wavelength light emitting source, can be configured. That is, according to this configuration, even when used for a backlight, it is possible to perform display with high luminance and a wide color gamut area for color reproduction. Also in this configuration, when the emission peak wavelength of the red light emitting LED is set to 600 nm or more, the stimulation purity for red is increased as in the case of the yellow light emitting phosphor, so that better color reproducibility can be obtained.

In the case of the configuration using the green light emitting phosphor, from the viewpoint of the color rendering property of the illumination light, the emission peak wavelength of the blue LED chip 11 is 440 to 470 nm, and the emission peak wavelength of the green light emitting phosphor is 520 to 560 nm. It is desirable that the emission peak wavelength of the red LED chip 12 is 600 to 650 nm. From the viewpoint of color reproduction as a backlight, the emission peak wavelength of the blue LED chip 11 is 440 nm or less, the emission peak wavelength of the green light emitting phosphor is 510 to 550 nm, and the emission peak wavelength of the red LED chip 12. It is preferable that the wavelength is 610 nm or more, desirably 630 nm or more.
(Embodiment 2)
In the present embodiment, a suitable combination of the blue LED chip 11, the red LED chip 12, and the phosphor 13 will be described. According to the LED lamp 100 of the first embodiment, as described above, the red LED chip 12 can introduce a red emission spectrum that is insufficient in white light emission by the conventional LED element, and therefore, an LED lamp with good color reproducibility. Can be provided. A problem in evaluating the color reproducibility of the LED lamp is the color reproducibility evaluation method. Hereinafter, this problem will be described.

  In the LED lamp 100 of the first embodiment, since the red emission spectrum that has been insufficient in the past is introduced, the special color rendering index R9 and the average color rendering index Ra showing red appearance are improved as compared with the conventional white LED lamp. It is easy to understand. However, it is not appropriate to judge the color reproducibility of the LED lamp only by the evaluation method based on these evaluation numbers. That is, the light emission of LEDs has a tendency to make the color look very vivid compared to the light emission of fluorescent lamps, light bulbs, and HID light sources conventionally used as illumination light sources. The evaluation of only the color rendering index or the special color rendering index cannot fully capture the characteristics of color rendering when an LED is used as a light source. The fact that LEDs emit light very vividly is a characteristic phenomenon when LEDs are used for illumination, and has a narrow spectral bandwidth with a narrow half-value width and no secondary emission wavelength. This is due to the characteristics of the LED that it has.

  In the LED lamp 100 of the first embodiment, the short wavelength side blue and the long wavelength side red in the visible light emission band have light emission with a narrow half-value width of the LED (see FIG. 4). Therefore, it is possible to make the color look very vivid compared to a light source such as a fluorescent lamp. The inventor of the present application has succeeded in deriving a spectral distribution suitable for the LED lamp 100 through numerous experiments and examinations. Hereinafter, the method for optimizing the color reproducibility of the LED lamp 100 performed by the present inventor will be described first, and then an example of a suitable spectral distribution in which the LED lamp 100 exhibits excellent color reproducibility will be described.

  First, the problem of evaluation based on the conventional color rendering index will be described. The conventional color rendering index is an evaluation to be performed when the color reproduction of various color rendering evaluation color charts with a reference light source such as synthetic daylight or blackbody radiation having a correlated color temperature equivalent to the light source to be evaluated is 100. It evaluates and indexes how much the color reproduction of the various color rendering evaluation color charts with the light source is different from the color reproduction with the reference light source. Therefore, the evaluation is highest when the color rendering with the evaluation light source matches the color rendering with the reference light source. If the evaluation color chart looks duller than the color rendering with the reference light source and, as a result, looks unfavorable, the color rendering evaluation is naturally lower, but conversely, the evaluation color chart looks more vivid than the color rendering with the reference light source, As a result, the color rendering evaluation also becomes low when it looks favorable. That is, there is a problem that the color rendering evaluation is lowered even when the image looks more vivid or the color looks conspicuous.

  Today, the things that surround human beings in everyday life are not only natural objects with medium saturation such as trees and stones, but also industrial products with artificially vibrant colors such as vivid blue and yellow. It's full. For this reason, when the evaluation color chart looks brighter than the color rendering with the reference light source, giving a low evaluation to the light source is not necessarily an appropriate evaluation. Therefore, the inventor of the present application has optimized the spectral distribution of the LED lamp in order to take advantage of the characteristics of the LED light source. Hereinafter, the optimization method performed by the present inventor will be described.

  The color rendering property evaluation method of the light source has international consistency, and is disclosed in JIS Z8726 in Japan. Among them, although not defined by international standards, a method based on a color gamut area ratio is generally indicated as an authorized method as a “color rendering property evaluation method other than based on the color rendering index”. This method is a method of evaluating by the ratio of the color gamut area composed of the test colors (R1 to R8) for calculating the average color rendering index. More specifically, the chromaticity coordinates from R1 to R8 used for calculating the average color rendering index are used, and the chromaticity coordinates when 8 points on the chromaticity coordinates rendered by the reference light source are connected. This is an evaluation method in which the ratio between the upper area and the area on the chromaticity coordinates when connecting the eight points on the chromaticity coordinates rendered by the evaluation light source is determined and used as the color gamut area ratio Ga.

  According to this evaluation method, when Ga is less than 100, the color appears to be dull because the saturation is reduced. On the other hand, when Ga is greater than 100, the color appears to have increased saturation. Therefore, it tends to look vivid. As described above, when the evaluation based on the color gamut area ratio is used instead of the evaluation based on the color reproduction deviation from the reference light source, it is possible to obtain an evaluation showing a favorable appearance even when Ra is low when the image looks vivid. it can. This evaluation method seems to be an effective evaluation index for evaluating the vivid color rendering characteristic of the LED. However, when only this index is used, Ra is evaluated better when Ga is increased, but Ra evaluated using the same evaluation test color is lowered, and a sense of incongruity due to color reproduction deviation from the reference light source is increased. End up. That is, when only the Ga index is used, consistency with the Ra index cannot be obtained.

  Therefore, the inventor of the present application introduced a color gamut area ratio using R9 to R12, which are special color rendering evaluation numbers for vivid red, yellow, green, and blue, as a new evaluation index. The evaluation method based on this evaluation index will be described. By taking over the calculation method shown in JISZ8726 similar to Ga using the evaluation test colors R1 to R8 described above, R9 to R12 are substituted for the evaluation test colors R1 to R8. This is a method for obtaining the color gamut area ratio by using it. Hereinafter, in this specification, the color gamut area ratio according to the special color rendering index R9 to R12 is referred to as “Ga4”.

  Originally, R1 to R8 are selected in order to evaluate a subtle difference in appearance of a natural object, and are test colors of medium saturation. On the other hand, R9 to R12 are evaluation color charts selected for evaluating the appearance of originally vivid objects. For this reason, by using Ga4, it is possible to extract and accurately evaluate whether or not an object that the user wants to show vividly appears. In other words, for objects that require subtle and accurate color appearance with medium saturation, color reproduction that is faithful to the colors of natural objects with Ga and Ra close to 100 and vivid colors As for the appearance of an object to be color-reproduced, performing color reproduction that increases Ga4 is the optimum color reproduction. By performing such optimization, more natural color reproduction can be performed with high contrast of color saturation and sharpness.

  This inventor performed the optimization process with respect to the LED lamp 100 of the said Embodiment 1, and obtained the following knowledge.

  (1) When the emission peak wavelength of the red LED chip 12 is 600 nm or more, the average color rendering index Ra can be increased. And if it is in the range of 610 nm to 630 nm, Ga4 can be raised while Ra is raised, and Ga4 can be made higher than Ga. In other words, within this range, it is possible to faithfully reproduce a medium chroma color for which subtle and precise color reproduction is desired, and vivid color reproduction can be performed for a high chroma color.

  Ra can be raised as the light emission peak wavelength of the blue LED chip 11 is 470 nm or less. And if it is in the range of 450 nm to 470 nm, Ga4 can be raised while Ra is raised, and Ga4 can be made higher than Ga.

  The emission peak wavelength of the phosphor 13 combined with such an LED chip is preferably in the range of 520 nm to 560 nm. Ra within the range of 545 nm to 560 nm is more preferable because Ra can often be increased.

  (2) When the correlated color temperature of the LED lamp 100 is 5000 K or more and the reference light source for color rendering evaluation is synthetic daylight, the emission peak wavelength of the blue LED chip 11 is in the range of 450 nm to 460 nm, More preferably, the emission peak wavelength of the red LED chip 12 is 600 nm or more, and the emission peak wavelength of the phosphor 13 is in the range of 520 nm to 560 nm.

  (3) When the correlated color temperature of the LED lamp 100 is less than 5000 K and the reference light source for color rendering evaluation is black body radiation, the emission peak wavelength of the red LED chip 12 is in the range of 615 nm to 650 nm, The emission peak wavelength of the phosphor 13 is more preferably in the range of 545 nm to 560 nm.

  (4) When the correlated color temperature of the LED lamp 100 is varied from low to high, the emission peak wavelength of the blue LED chip 11 is in the range of 455 nm to 465 nm, and the emission peak wavelength of the red LED chip 12 is More preferably, the emission peak wavelength of the phosphor 13 is in the range of 540 nm to 550 nm.

  Examples of the LED lamp 100 that has been optimized for color reproduction are shown in FIGS. 8 to 10 and Tables 1 to 3. FIG.

  FIG. 8A shows an example of the spectral distribution of the LED lamp 100 that has been optimized for the case of 3000 K as a representative of those having a low correlated color temperature. 3000K is a level close to the lower limit of the correlated color temperature in a commonly used illumination light source. In the case of 3000K, the reference light source to be compared when calculating Ra is blackbody radiation. In this example, the emission peak wavelength of the blue LED chip 11 is 460 nm, the emission peak wavelength of the red LED chip 12 is 625 nm, and the emission peak wavelength of the phosphor 13 is 545 nm.

  FIG. 8B is a graph showing the color gamut area ratio by Ga for the LED lamp 100 having the spectral distribution shown in FIG. 8A, and FIG. 8C is the color gamut area by Ga4. It is a graph which shows ratio. In Table 1 below, in addition to the above conditions, the chromaticity values (x, y), Duv, color rendering properties (Ra, R1 to R15) and color gamut area ratio of the LED lamp 100 in FIG. It shows.

  Similar to FIG. 8A, FIG. 9A shows an example of the spectral distribution of the LED lamp 100 that has been optimized for a case where the correlated color temperature is 5000K as a representative one of the medium correlated color temperatures. 5000K is a point at which the reference light source to be compared switches from black body radiation to synthetic daylight when calculating Ra. In this example, the emission peak wavelength of the blue LED chip 11 is 460 nm, the emission peak wavelength of the red LED chip 12 is 640 nm, and the emission peak wavelength of the phosphor 13 is 545 nm. FIGS. 9B and 9C are graphs showing the color gamut area ratios of Ga and Ga4, respectively. Similar to Table 1, the following Table 2 shows, in addition to the above conditions, the chromaticity values (x, y), Duv, color rendering properties (Ra, R1 to R15) of the LED lamp 100 for FIG. The gamut area ratio is also shown.

  FIG. 10A shows an example of the spectral distribution of the LED lamp 100 that has been optimized for a correlated color temperature of 6700K. 6700K is a level close to the upper limit of the correlated color temperature in a commonly used illumination light source. In the case of 6700K, the reference light source to be compared in the calculation of Ra is synthetic daylight. In this example, the emission peak wavelength of the blue LED chip 11 is 460 nm, the emission peak wavelength of the red LED chip 12 is 640 nm, and the emission peak wavelength of the phosphor 13 is 545 nm. FIGS. 10B and 10C are graphs showing the color gamut area ratios of Ga and Ga4, respectively. Similar to Table 1, in addition to the above conditions, Table 3 below shows chromaticity values (x, y), Duv, color rendering properties (Ra, R1 to R15) of the LED lamp 100 for FIG. The gamut area ratio is also shown.

  Representative examples of patterns studied by the inventors of the present application for the combination of the blue LED chip 11, the red LED chip 12, and the phosphor 13 are shown in FIGS. In the drawing, the vertical axis represents Ra of the LED lamp 100, and the horizontal axis represents the emission peak wavelength (nm) of the red LED chip 12. Ra of the LED lamp 100 is based on actual measurement or simulation results. At each point (circle mark, triangle mark, square mark) in the figure, the examinations as shown in FIGS. 8A to 8C and Table 1 are performed.

  FIGS. 11A to 11C are examples of correlated color temperatures of 3000K, 5000K, and 6700K, respectively. The emission peak wavelength of the blue LED chip 11 is fixed at 450 nm, and the emission peak wavelength of the phosphor 13 is changed from green at 520 nm to yellow at 560 nm (560 nm (circle), 545 nm (triangle)), 520 nm (square mark)). The emission peak wavelength (nm) of the red LED chip 12 is changed from 595 nm to 670 nm.

  Similarly, FIGS. 12A to 12C are examples of correlated color temperatures of 3000K, 5000K, and 6700K, respectively, and the emission peak wavelength of the blue LED chip 11 is fixed at 460 nm. On the other hand, FIGS. 13A to 13C are examples of correlated color temperatures of 3000K, 5000K, and 6700K, respectively, and the emission peak wavelength of the blue LED chip 11 is fixed at 470 nm.

  Based on the results of FIGS. 8 to 13 and Tables 1 to 3, the above-mentioned findings by the inventors will be described in further detail.

  In JIS, a high color rendering three-wavelength region emission fluorescent lamp is defined as Ra80 or more. When designing the LED lamp 100 aiming at high color rendering properties of Ra 80 or higher, taking the above results together, the range in which the average color rendering index is increased is the range in which the emission peak of the red LED chip 12 is 600 nm or higher. It was. If it is in such a range, LED80 100 of Ra80 or more is realizable. In particular, the preferred range in which the average color rendering index is high or the average color rendering index tends to saturate is when the emission peak of the red LED chip 12 is in the range of 610 nm to 630 nm. In such a range, it is possible to perform faithful color rendering for medium-saturation colors for which subtle and precise color reproduction is desired. In addition, the LED lamp 100 has a short wavelength in the visible light emission band. Since both the side and the long wavelength side have the spectrum of LEDs with a narrow half-value width and high purity, it is possible to reproduce colors vividly for highly saturated colors. That is, in addition to the height of Ra, it is possible to realize a preferable viewing environment having a contrast with respect to saturation, that is, with a sharp color.

  The range for increasing the average color rendering index was 470 nm or less for the emission peak wavelength of the blue LED chip 11. When the emission peak wavelength is longer than this, the present inventor has confirmed through experiments that it is difficult to realize an LED lamp 100 having a particularly high correlated color temperature and that Ra is more than 80. In addition, it has been found that when the wavelength exceeds 470 nm, even if the LED lamp 100 having a low correlated color temperature is to be realized, the combination range of emission peaks of the red LED chip 12 that can increase Ra is narrowly limited. On the other hand, the lower limit of the emission peak wavelength of the blue LED chip 11 is desirably 450 nm or more. If it is below 450 nm, it becomes difficult for Ra to exceed 90, and particularly when realizing the LED lamp 100 having a high correlated color temperature, the band of the emission wavelength of the phosphor 13 that can be combined is more limited. It is.

  From the viewpoint of luminous efficiency, the following can be said. When the emission peak wavelength of the red LED chip 12 deviates from the range of 610 nm to 630 nm, the emission efficiency (lm / W) decreases. Therefore, from the viewpoint of the emission efficiency, it is preferable to set the emission peak wavelength within the range of 610 nm to 630 nm. Further, when the emission peak wavelength of the blue LED chip 11 is also less than 450 nm, the light emission efficiency (lm / W) is lowered. Therefore, similarly to the red LED lamp 12, the blue LED lamp 11 is preferably set to 450 nm or more. .

  Moreover, it turned out that the range of the emission peak of the phosphor 13 combined with the LED chip (particularly, the blue LED lamp 11) is preferably 520 nm to 560 nm. In combination with various LED chips, it is more preferable to set the range from 545 nm to 560 nm, which gives a high tendency to Ra, as a whole.

  I also found out that: In the case of the LED lamp 100 in which the same LED chip and the same phosphor are used in the wide correlated color temperature range from the low color temperature to the high color temperature, and only the power ratio is changed while having the same peak wavelength. In order to increase the average color rendering index, the emission peak range of the blue LED chip 11 is changed from 455 nm to 465 nm, the emission peak range of the red LED chip 12 is changed from 620 nm to 630 nm, and the emission peak range of the phosphor 13 is changed from 540 nm. 550 nm is preferable.

  Considering the case of specializing in the realization of high color rendering of Ra 90 or higher at various correlated color temperatures without specializing in the light source that can change the light color greatly, the following can be said. High color rendering of Ra 90 or higher is the color rendering group 1A (Ra ≧ 90) referred to in the CIE color rendering classification, and is of a level that can be used sufficiently for applications that require strict color rendering (for example, for museums). It is. When the correlated color temperature is relatively high and the reference light source for color rendering evaluation is synthetic daylight (that is, 5000 K or more), the emission peak of the red LED chip 12 is 600 nm or more and the emission peak of the blue LED chip 11 The range is 450 nm to 460 nm, and more desirably, the peak wavelength of the combined phosphor may be 520 nm to 545 nm. On the other hand, when the correlated color temperature is relatively low and the reference light source for color rendering evaluation is black body radiation, the emission peak of the red LED chip 12 is 615 nm to 650 nm, and the peak wavelength of the combined phosphor is 545 nm to 560 nm. I just need it.

  Furthermore, particularly excellent examples in the range where Ra and Ga are high and Ga4 is high are the combination examples shown in FIGS. A person skilled in the art can realize an LED lamp 100 having high Ra and Ga and high Ga4 even when the emission peak wavelengths of the combination are slightly shifted (for example, about ± 5 to 10 nm). Easy to understand.

  When the correlated color temperature is relatively low (for example, 3000 K), the emission peak wavelength of the blue LED chip 11 is 460 nm, the emission peak wavelength of the red LED chip 12 is 625 nm, and the emission peak of the phosphor 13 The wavelength is in the range of 545 nm. In this range, the LED lamp 100 with Ra = 92.4, Ga = 103.3, and Ga4 = 109.3 can be realized.

  When the correlated color temperature is intermediate (for example, 5000 K), the emission peak wavelength of the blue LED chip 11 is 460 nm, the emission peak wavelength of the red LED chip 12 is 640 nm, and the emission peak of the phosphor 13 The wavelength is in the range of 545 nm. In this range, the LED lamp 100 with Ra = 94.3, Ga = 101.6, and Ga4 = 112.9 can be realized.

  When the correlated color temperature is relatively high (for example, 6700 K), the emission peak wavelength of the blue LED chip 11 is 460 nm, the emission peak wavelength of the red LED chip 12 is 640 nm, and the emission peak of the phosphor 13 The wavelength is in the range of 545 nm. In this range, an LED lamp 100 with Ra = 92.2, Ga = 96.6, and Ga4 = 107.5 can be realized.

  Since the LED lamp of this embodiment has been studied for optimization by Ga and Ga4 for a range where Ra is high, the color reproduction distribution of each test color is less distorted and the color is more vivid. It becomes a visible light source. In other words, the bright red, yellow, green, and blue test colors of R9 to R12 that are used for the special color rendering index are test color charts that represent artificial vivid colors, so that Ra (and Ga) is Maximizing Ga4 constituted by this test color chart under high conditions can realize a light source that renders only vivid colors more vividly while making natural colors appear more natural. Since the spectral reflectance of these brightly colored objects generally shows a sharp change in spectral distribution with a specific wavelength as a boundary, a light emitting diode having a narrow half-value width of the spectral distribution can be preferably used. As a result, it is possible to realize an unprecedented, high-quality illumination light source that reproduces natural objects more naturally, and has a clear color contrast that allows objects with artificially vivid colors to be reproduced more vividly. Become.

If the focus is on making the colors appear more vivid, Ra need not be made higher than necessary, so the range in which such LED lamps can be realized will be wider than the range described above. .
(Embodiment 3)
The LED lamp according to Embodiment 3 of the present invention will be described with reference to FIGS. In the first embodiment, the LED lamp 100 is composed of two LED bare chips, that is, one blue LED bare chip 11 and one red LED bare chip 12, but in this embodiment, the light emitting portion of the blue LED and the red LED An LED lamp is composed of one LED bare chip including both the light emitting portion. This point is different from the LED lamp 100 of the first embodiment. The other points are the same as those of the first embodiment, and thus the description of the same points as those of the first embodiment is omitted or simplified for the sake of simplification. Needless to say, the configuration of the second embodiment in which the LED lamp 100 is optimized can also be applied to the LED lamp of the present embodiment.

  In this embodiment, since one LED bare chip that emits two emission colors is used, the following advantages can be obtained as compared with the first embodiment in which two emission color bare chips need to be arranged side by side. That is, since only one LED bare chip is used, the red and blue light emission positions are as close as possible to each other on one LED bare chip. As a result, an LED lamp that is more advantageous for color mixing can be realized. Furthermore, since both the red light emitting part and the blue light emitting part are more thermally bonded, the temperature between both light emitting parts is made uniform. As a result, since both can be regarded as being thermally identical, feedback control of the influence of heat on the light output can be facilitated.

  First, a process for manufacturing one LED bare chip that emits red and blue will be described with reference to FIGS.

  First, as shown in FIG. 14A, a first light emitting diode light emitting layer (hereinafter referred to as “a light emitting diode light emitting diode”) including at least a P type semiconductor layer, an N type semiconductor layer, and an active layer on a substrate 115 for forming a light emitting diode. The “light emitting diode light emitting layer” is referred to as “LED light emitting layer”.) 111 is formed.

  Next, as shown in FIG. 14B, the substrate 115 is peeled off to obtain the first LED light emitting layer 111. The separation of the substrate 115 may be appropriately selected depending on the types of the substrate 115 and the LED light emitting layer. For example, a technique such as polishing of the substrate 115, mechanical separation, removal of the substrate 115 by etching, or separation by thermal stress may be employed. .

  Next, as shown in FIG. 14C, when the first LED light emitting layer 111 is attached to the substrate 115 ′ on which the second LED light emitting layer 112 is formed, an LED bare chip that emits two light emission colors. Is obtained. Thus, after each or any one of the light emitting layer and red LED of a blue LED is peeled, it is bonded together to form one LED bare chip.

  Hereinafter, a combination pattern of bonding will be exemplified with reference to FIGS. 15 to 18. There are many variations of this bonding, but the main patterns are shown below. For convenience, the first LED light-emitting layer is referred to as a blue LED light-emitting layer 111, and the second LED light-emitting layer is referred to as a red LED light-emitting layer 112. A phosphor 13 is formed around these LED light emitting layers.

  FIG. 15A shows an example of a double-sided electrode structure when the substrate 115 is conductive. In the case of this structure, one electrode may be provided on the upper surface of the upper blue LED light-emitting layer 111 and one electrode may be provided on the lower surface of the lower red LED light-emitting layer 112 with the substrate 115 interposed therebetween.

  FIG. 15B shows an example of a single-sided electrode structure when the light-emitting diode substrate is non-conductive. In the case of this structure, two electrodes may be provided on the upper surface of the upper blue LED light-emitting layer 111 and two electrodes on the lower surface of the lower red LED light-emitting layer 112 with the substrate 115 interposed therebetween.

  FIG. 15C shows an example in which the single-sided electrode structure and the double-sided electrode structure are combined when the substrate 115 is conductive. In the case of this structure, one electrode may be provided on the upper surface of the upper blue LED light emitting layer 111 and two electrodes on the lower surface of the lower red LED light emitting layer 112 with the substrate 115 interposed therebetween.

  FIG. 16A shows an example in which LED light emitting layers are stacked on one side of the substrate 115 when the substrate 115 is conductive. In the case of this structure, one electrode may be provided on the upper surface of the upper red LED light emitting layer 112 and one electrode on the lower surface of the substrate 115.

  FIG. 16B shows an example in which a double-sided electrode and an LED light-emitting layer of a single-sided electrode are stacked on one side of the substrate 115 when the substrate 115 is conductive. In the case of this structure, it is only necessary to provide one electrode on the upper surface of the substrate 115 and two electrodes on the lower surface of the lower red LED light emitting layer 112.

  FIG. 16C shows an LED light emitting layer (blue LED light emitting layer) 111 that emits short wavelength light below the substrate 115, and light from the LED light emitting layer 111 that emits light of the short wavelength. The LED active layer (red LED active layer) 112 ′ excited and emitted in FIG. In the case of this structure, two electrodes may be provided on the lower surface of the LED light emitting layer 111.

  The structure shown in FIGS. 15 and 16 is an example of a number of possible combinations. In addition to variations in the rearrangement of the LED light-emitting layers of the respective emission colors, FIGS. 15C and 16A to 16C are used. In the structure shown in (2), there is also an inversion pattern for the vertical relationship.

  In addition, each LED light emitting layer (111, 112) may be spatially juxtaposed on the same substrate 115 instead of being laminated on one side or both sides of the same substrate 115. An example of such a structure is shown in FIGS.

  FIG. 17A shows a structure in which LED light emitting layers (111, 112) of the respective colors are formed on one conductive substrate 115. In the case of this structure, a common electrode may be provided on the lower side of the substrate 115, and one electrode may be provided on the upper surface of each LED light emitting layer.

  FIG. 17B shows a structure in which the LED light emitting layers (111, 112) of the respective colors are formed on one nonconductive substrate 115. In the case of this structure, two electrodes may be provided on the upper surface of each LED light emitting layer.

  FIG. 17C shows a pattern in which the vertical relationship of the structure shown in FIG.

  FIG. 18A shows a structure in which the LED light emitting layers (111, 112) of the respective colors are formed on one conductive substrate 115. FIG. In the case of this structure, one electrode common to the lower side of the substrate 115 is provided, and one electrode is provided on the upper surface of each LED light emitting layer, and two electrodes are provided on the upper surface of each LED light emitting layer. The provided ones are mixed.

  FIG. 18B shows a structure in which the LED light emitting layers are juxtaposed. In the case of this structure, the substrate 115 is not necessary, and the bonding process shown in FIG.

  FIG. 18C shows a structure in which two LED light emitting layers of double-sided electrodes are laminated as they are. Even in this structure, the substrate 115 is unnecessary. Further, in the case of this concept, there may be a variation in which the LED light emitting layers of single-sided electrodes and double-sided electrodes are laminated, or a variation in which four LED light emitting layers are laminated.

  The structure shown in FIGS. 17 and 18 is also an example of many possible combinations. In addition to variations in the rearrangement of the LED light-emitting layers of the respective emission colors, FIG. 17A, FIG. 18A and FIG. There is also a reversal pattern of the vertical relationship of the structure shown in FIG.

In the present embodiment, since the light emitting layer 111 of the blue light emitting LED element 11 and the light emitting layer 112 of the red light emitting LED element 12 are integrally configured as one LED chip, the light emission positions of both are the same as much as possible. It approaches and becomes more advantageous for color mixing. Furthermore, since both are more thermally bonded, the temperature between both light emitting layers is made uniform, and both can be regarded as being thermally the same. As a result, feedback control of the influence of heat on the light output can be facilitated.
(Embodiment 4)
The LED lamp 500 according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 19 schematically shows the configuration of the LED lamp 500. The LED lamp 100 according to the first embodiment is configured as an integral element, but the LED lamp 500 according to the present embodiment is different in that it is configured as a cluster instead of an integral element. In the following, in order to simplify the description, points different from the first embodiment will be mainly described, and descriptions of the same points as in the first embodiment will be omitted or simplified.

  As shown in FIG. 19, the LED lamp 500 of this embodiment includes a white light emitting LED element 52 composed of a blue LED chip 11 and a yellow light emitting phosphor 13 that emits light when excited by the blue LED chip 11, and a red LED chip. The red light emitting LED elements 54 including 12 are clustered in a planar manner. That is, the white light emitting LED elements 52 and the red light emitting LED elements 54 are arranged in a plane.

  In the present embodiment, the white light emitting LED element 52 includes a bullet-shaped transparent resin portion 16 that seals the blue LED chip 11 disposed on the base 17 of the lead frame 14 and the yellow light emitting phosphor 13 covering the blue LED chip 11. The red light emitting LED element 54 includes the red LED chip 12 disposed on the base 17 of the lead frame 14 and the bullet-shaped transparent resin portion 16 that seals the red LED chip 12. The white light emitting LED elements 52 and the red light emitting LED elements 54 are arranged alternately, for example.

  In the LED lamp 500 of this embodiment, since the white light emitting LED element 52 and the red light emitting LED element 54 having different constituent materials can be individually manufactured and clustered in one lamp unit, each LED element design can be changed. Optimal design can be made individually. Moreover, since the non-defective products of the respective LED elements can be selected and clustered into one lamp unit, the industrial yield can be improved. Furthermore, there is an advantage that the heat radiation design becomes easy.

  Even if the output light flux of the blue LED chip 11 and the output light flux of the red LED chip 12 are different, each LED chip is configured as an individual element, so the ratio of the number of clusters is arbitrarily set. As a result, the degree of freedom in lamp design can be increased. That is, the configuration of this embodiment increases the degree of freedom in lamp design rather than clustering elements in which the blue LED chip 11 and the red LED chip 12 are preliminarily incorporated in a certain element at a certain ratio. Can do.

  In the case of the LED lamp 500, each of the light-colored LED chips 52 and 54 serving as the light source emits light at spatially separated locations as individual elements, and thus the LED lamp 100 of the first embodiment. Compared to the case where the integrated element is configured as described above, the mixed light unevenness tends to increase. For the purpose of reducing such color mixture unevenness, a three-dimensional clustered LED lamp 600 may be used as shown in FIG.

  The LED lamp 600 has a white light emitting LED element 62 composed of a blue LED chip 11 and a yellow light emitting phosphor 13 that emits light when excited by the blue LED chip 11, and a red light emitting LED element 64 including the red LED chip 12. The white light emitting LED elements 62 and the red light emitting LED elements 64 are arranged to have different heights. According to the LED lamp 600, the individual elements 62 and 64 are three-dimensionally arranged, so that the light output from the LED elements 62 and 64 can be reflected and refracted to each other. It becomes possible to reduce. The LED lamp 600 is configured to further improve the light mixing characteristics by combining a bullet-shaped LED element 62 having a relatively narrow light distribution characteristic and a square LED element 64 having a relatively wide light distribution characteristic. is doing.

  As described in the first embodiment, the LED lamps 500 and 600 are configured such that the light emission intensity ratio between the white light emitting LED chip 52 (or 62) and the red light emitting LED element 54 (or 64) can be changed. Thus, a light color variable LED lamp can be formed. Moreover, it is also possible to use a green light emitting phosphor instead of the yellow light emitting phosphor 13. In this case, a blue light emitting LED element 52 (or 62) combining a blue LED chip 11 and a green light emitting phosphor that emits light when excited by the blue LED chip 11, and a red light emitting LED element 54 (or 62) having a red LED chip 12. 64) and the LED lamp 500 (or 600).

In the above embodiment, as the blue light-emitting LED element (blue LED chip) 11, a GaN-based blue LED chip (GaN-based not only GaN but also AlInGaN and InGaN) is used and this is a yellow light-emitting fluorescent light. However, the present invention is not limited to this, and a ZnSe blue light emitting LED element (ZnSe blue LED chip) may be used. A ZnSe substrate is formed by a ZnSe blue light emitting LED element (ZnSe blue LED chip). A configuration in which yellow fluorescent light is emitted to form a white light emitting LED element can also be employed. In this case, the ZnSe substrate becomes a phosphor.
(Embodiment 5)
The LED lamp in the above embodiment can be combined with a power supply device that supplies power to the LED lamp to form a lamp unit. FIG. 21 schematically shows the configuration of the lamp unit 1000 in the present embodiment.

The lamp unit 1000 according to the present embodiment includes the LED lamp 100 according to the first embodiment, a reflector 110 that reflects light emitted from the LED lamp 100, a power supplier 120 that supplies power to the LED lamp 100, and a power supplier. And a base 130 connected to 120. A plurality of LED lamps 100 can be arranged on the bottom surface of the reflector 110, for example, about 10 to 200 can be arranged. Furthermore, when the reflecting plate 110 is thermally coupled to the LED lamp 100, the reflecting plate 110 serves as a heat sink, so that it is possible to contribute to an improvement in heat dissipation of the LED lamp 100. As a result, the LED lamp 100 can be used with a longer life. As the reflector 110, a diffuse reflector (for example, a white reflector) or a specular reflector (reflector) can be used.

  In the case of the lamp unit 1000 provided with about 60 LED lamps 100, the beam luminous flux (the luminous flux included in the beam angle) is 60 lm, the lamp life is 10,000 hours, and the luminous efficiency is about 30 to 50 lm / W. Confirmed by the inventor. This characteristic is very superior compared to the characteristics of a conventional lamp unit (a beam flux: about 60 lm, lifetime: 2000 hours, luminous efficiency: about 15 lm / W) that combines a halogen bulb that is not an LED lamp and a dichroic mirror. You can see that Moreover, since the LED lamp 100 attached to the lamp unit 1000 is a semiconductor element, there is no problem such as a bulb breakage. Therefore, there is also an advantage that handling is easy.

  Moreover, the lamp unit 1000 which can change light color can also be provided by making the LED lamp 100 into a light color variable LED lamp. In this case, the power supply 120 may be provided with the circuit 200 illustrated in FIG. For example, an AC / DC converter may be provided in the power supply unit 120. In the example shown in FIG. 21, a light color variable dial 122 and a brightness variable dial 124 are attached to the power supply 120 so that the light color and brightness of the illumination can be adjusted by dial operation. It is composed.

  Although this embodiment has been described using the LED lamp 100, the present invention is not limited to this, and the LED lamps of the second and third embodiments, the LED lamp 500 or 600 of the fourth embodiment, and the power supply unit 120 are included. A lamp unit may be configured in combination. The reflector 110 and the base 130 of the lamp unit 1000 can be provided or not provided depending on various uses. It is also possible to employ a configuration in which about 60 LED lamps 100 are used as one unit, and that one unit is used as one light source. Moreover, you may make it the structure which uses the 1 unit in multiple numbers.

  As described above, the LED lamp according to the present invention can emit white light with good color reproducibility and high luminous efficiency, and is useful as a white light emitting LED lamp.

It is a figure which shows typically the structure of the LED lamp 100 concerning Embodiment 1. FIG. 6 is a graph for schematically explaining the spectral distribution of the LED lamp 100. 6 is a graph for schematically explaining the spectral distribution of the LED lamp 100. 3 is a graph showing an example of a spectral distribution of an LED lamp 100. (A)-(d) is a graph which shows an example at the time of changing the spectral distribution of the LED lamp 100. FIG. It is a circuit diagram which shows typically the circuit 200 which comprises a light color variable LED lamp. 3 is a graph showing the chromaticity of the LED lamp 100. (A) is a graph which shows the spectral distribution of the LED lamp 100 which optimized in the case of 3000K. (B) is a graph which shows the color gamut area ratio by Ga. (C) is a graph which shows the color gamut area ratio by Ga4. (A) is a graph which shows the spectral distribution of the LED lamp 100 which optimized in the case of 5000K. (B) is a graph which shows the color gamut area ratio by Ga. (C) is a graph which shows the color gamut area ratio by Ga4. (A) is a graph which shows the spectral distribution of the LED lamp 100 which optimized in the case of 6700K. (B) is a graph which shows the color gamut area ratio by Ga. (C) is a graph which shows the color gamut area ratio by Ga4. (A)-(c) is a graph which shows the relationship between the light emission peak wavelength (nm) of the red LED chip 12, and Ra. (A)-(c) is a graph which shows the relationship between the light emission peak wavelength (nm) of the red LED chip 12, and Ra. (A)-(c) is a graph which shows the relationship between the light emission peak wavelength (nm) of the red LED chip 12, and Ra. (A)-(c) is process sectional drawing for demonstrating the preparation process of one LED bare chip which emits red and blue. (A)-(c) is a figure which shows typically the cross-sectional structure of the LED bare chip in Embodiment 3. FIG. (A)-(c) is a figure which shows typically the cross-sectional structure of the LED bare chip in Embodiment 3. FIG. (A)-(c) is a figure which shows typically the cross-sectional structure of the LED bare chip in Embodiment 3. FIG. (A)-(c) is a figure which shows typically the cross-sectional structure of the LED bare chip in Embodiment 3. FIG. It is a figure which shows typically the structure of the LED lamp 500 in Embodiment 4. FIG. It is a figure which shows typically the structure of the LED lamp 600 in Embodiment 4. FIG. It is a figure which shows typically the structure of the lamp unit 1000 concerning Embodiment 5. FIG.

Explanation of symbols

11 Blue light-emitting LED element (blue LED chip)
11a Luminous intensity adjustment means (variable resistance)
12 Red LED element (red LED lamp)
12a Luminous intensity adjustment means (variable resistance)
13 Phosphor (yellow light-emitting phosphor, green light-emitting phosphor)
14 Lead frame 15 Bonding wire 16 Transparent resin part 17 Base 21 Emission spectrum of blue light emitting LED element 22 Emission spectrum of yellow light emitting phosphor 23 Emission spectrum of red light emitting LED element 30 Black body radiation locus 41 Chromaticity of blue LED chip 42 Yellow Chromaticity of light emitting phosphor 43 Chromaticity of white light emission by blue LED chip and yellow light emitting phosphor 44 Chromaticity of red LED chip 52, 62 White light emitting LED element 54, 64 Red light emitting LED element 100 LED lamp 110 Reflector 120 Power supply 122 Light color variable dial 124 Brightness variable dial 130 Base 500 LED lamp 600 LED lamp 1000 Lamp unit

Claims (11)

Only a blue light emitting LED element and a red light emitting LED element are provided as light emitting LED elements,
Further, a yellow light-emitting phosphor that is excited by the blue light-emitting LED element, and has a wavelength band between a blue wavelength band that the blue light-emitting LED element emits light and a red wavelength band that the red light-emitting LED element emits light. An LED lamp comprising: a yellow light-emitting phosphor that emits an emission spectrum that supplements emission intensity over a wide band. The peak wavelength of the red light emitting LED element is 600 nm or more,
2. The LED lamp according to claim 1, wherein a peak wavelength of the yellow light emitting phosphor is not less than 550 nm and not more than 590 nm. The red light emitting LED element has a peak wavelength in a range of 610 nm to 630 nm,
The gamut area ratio Ga4 composed of R9 to R12, which is a special color rendering index, is higher than the gamut area ratio Ga, composed of R1 to R8, which is an average color rendering index. LED lamp.   The LED lamp according to any one of claims 1 to 3, further comprising emission intensity adjusting means for adjusting the emission intensity of the red LED element.   The LED lamp according to claim 4, wherein the light emission intensity adjusting means is a variable resistor.   The LED lamp according to claim 1, wherein the yellow light emitting phosphor is a YAG phosphor or a phosphor having a Mn emission center.   The LED lamp according to any one of claims 1 to 6, wherein the blue light-emitting LED element, the red light-emitting LED element, and the yellow light-emitting phosphor are integrally configured.   The LED lamp according to claim 7, wherein a light emitting portion of the blue light emitting LED element and a light emitting portion of the red light emitting LED element are provided in one chip.   The LED lamp according to any one of claims 1 to 8, wherein the LED element including the blue light-emitting LED element and the yellow light-emitting phosphor and the red light-emitting LED element are clustered.   A lamp unit comprising: the LED lamp according to claim 1; and a power supply unit that supplies power to the LED lamp. The lamp unit according to claim 10, further comprising a reflector that reflects light emitted from the LED lamp.

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