JP2004080046A - Led lamp and lamp unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an LED (light emitting diode) lamp whose color rendering properties are excellent and has high emission efficiency. <P>SOLUTION: The LED lamp 100 is excited by a blue light emitting LED element 11 and a red light emitting element 12, and is equipped with a phosphor 13 which emits emitting spectra compensating the emission strength of the light wavelength band between the blue wavelength band emitted by the blue emitting LED element 11 and the red wavelength band emitted by the red emitting LED element 12. <P>COPYRIGHT: (C)2004,JPO

Description

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

(4) A light-emitting diode element (hereinafter, referred to as an “LED element”) is a semiconductor element that is small, efficient, and emits bright colors, and has an excellent monochromatic peak. In the case of emitting white light using LED elements, 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. , Color unevenness is likely 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 occurs. 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 emits yellow when excited by the light emission. According to this technique, white light emission is obtained by using only one type of LED element, so that the problem of color unevenness that occurs when a plurality of types of LED elements are brought close to each other to obtain white light emission can be solved.
JP-A-10-242513

Conventionally, LED elements have been applied mainly as display elements, and there has been little research and development when LED elements are used as illumination lamps. When an LED element is used as a display element, the characteristics of the luminescent color of the self-emission emitted from the LED element may be a problem, but when used as a lamp, the color rendering property when illuminating an object is also a problem. It is necessary to The fact is that an LED lamp that has been studied up to the optimization of color rendering properties has not yet been developed.

ＬＥＤ The LED element disclosed in the above-mentioned publication can certainly emit white light, but when the LED element is used as a lamp, the present inventor has found that there are the following problems. In the above-mentioned conventional LED element, a white light emission color is created by the light emission of the blue LED element and the light emission of the yellow phosphor, so that the emission spectrum of 600 nm or more, which is a red component, is insufficient. If the emission spectrum (red component) of 600 nm or more is insufficient, there arises a problem that when applied to illumination and backlight, the reproduction of red is reduced. Further, since the red component is insufficient, it is difficult to configure a white light emitting LED element having a relatively low correlated color temperature. According to the results examined by the inventor of the present application, the average color rendering index Ra of the conventional white LED is such that poor red reproducibility can be obtained 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 exceed the value of about 85 due to the influence. When evaluated by the value of the special color rendering index R9 indicating the appearance of red color, poor red reproducibility clearly appears, and R9 of the conventional white LED shows only a low value of about 50.

発 明 Further, the inventors of the present application have studied a configuration in which a red phosphor is further provided in the configuration of the LED element disclosed in the above publication to supplement the emission spectrum of 600 nm or more. However, in this configuration, since the red phosphor is excited by the emission of the blue LED to emit red light, the energy conversion efficiency is extremely deteriorated. That is, the conversion from blue to 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, the configuration using the red phosphor is not practical.

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

A first LED lamp according to the present invention is a blue light emitting LED element, a red light emitting LED element, and a phosphor excited by the blue light emitting LED element, wherein a blue wavelength band in which the blue light emitting LED element emits light. A phosphor that emits an emission spectrum that compensates for the emission intensity of the wavelength band between the red wavelength band in which the red light-emitting LED element emits light, and a correlated color temperature of the LED lamp of 5000 K or more. In the case where the reference light source for color rendering evaluation is synthetic daylight, the peak wavelength of the blue light emitting LED element is in a range of 450 nm to 460 nm, and the peak wavelength of the red light emitting LED element is 600 nm or more, In addition, the emission peak wavelength of the phosphor ranges from 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, and a phosphor excited by the blue light-emitting LED element, wherein the blue light-emitting LED element emits blue light. A phosphor that emits an emission spectrum that supplements the emission intensity of the wavelength band between the red wavelength band that the red light-emitting LED element emits, and a correlated color temperature of the LED lamp is less than 5000K. The peak wavelength of the blue light emitting LED element is in a range of 450 nm to 460 nm when the reference light source for color rendering evaluation is black body radiation, and the peak wavelength of the red light emitting LED element is in a range of 615 nm to 650 nm. In addition, the emission peak wavelength of the phosphor ranges from 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 the range of 610 nm to 630 nm, and is smaller than the color gamut area ratio Ga constituted by the average color rendering index R1 to R8. The color gamut area ratio Ga4 composed of the numbers R9 to R12 is high.

In one embodiment, the light emitting device further includes a light emission intensity adjusting means for adjusting the light emission intensity of the red light emitting LED element.

In one embodiment, the 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 integrally formed.

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 configured in a cluster.

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

In one embodiment, the light emitting device further includes a reflector that reflects light emitted from the LED lamp.

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 was insufficient in white light emission by the conventional LED element, without lowering the light emission efficiency of the lamp. it can. Therefore, it is possible to provide an LED lamp capable of emitting white light with good color reproducibility and high luminous efficiency.

Further, 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. Further, when a light emitting intensity adjusting means for adjusting the light emitting intensity of the red light emitting LED element is further provided, it is possible to adjust the light emitting intensity of the red light emitting LED element. Can be.

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. Further, in the case where light emission intensity adjusting means for adjusting the light emission intensity of the red light emitting LED element is further provided, it is possible to adjust the light emission intensity of the red light emitting LED element. Can be.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, components having substantially the same function are denoted by the same reference numeral for the sake of simplicity.

(Embodiment 1)
FIG. 1 schematically shows a 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 to emit 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 a GaN material, and the red LED chip is a red light emitting LED having a light emitting layer of an AlInGaP, GaAsP, or GaAlAs material. It is a bare chip. A light emitting layer made of such a material becomes a light emitting portion of the LED.

The phosphor 13 emits light in a wavelength band between a blue wavelength band in which the blue light emitting LED element (blue LED chip) 11 emits light and a red wavelength band in which the red light emitting LED element (red LED chip) 12 emits light. Emit the emission spectrum that makes up. The phosphor 13 is, for example, a phosphor that is excited by the blue LED chip 11 and emits any color in a range from green to yellow, and is preferably a yellow light-emitting phosphor or a green light-emitting phosphor. The light emission of the phosphor 13 is not limited to fluorescent light, but may be phosphorescence.

FIG. 2 schematically shows the spectral distribution (emission spectrum distribution) of the LED lamp 100, where the horizontal axis represents the wavelength and the vertical axis represents the emission intensity. 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. An emission spectrum (G-Y) 22 of any color (for example, yellow) in the range and a 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 a red component emission spectrum 23 in addition to the emission spectra 21 and 22, so that 600 nm which is insufficient in the white light emission by the conventional LED element. White light emission in which the above emission spectrum is supplemented can be performed. The red 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, so that the luminous efficiency of the lamp does not decrease. That is, when a red emission spectrum is generated using the emission of the blue LED chip 11, the luminous efficiency of the lamp is significantly reduced 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 light emission spectrum 23 is directly generated from the red LED chip 12, the white light of good color reproducibility supplemented with the red component can be obtained without lowering the light emission efficiency of the lamp. It can emit light.

When the emission spectra 21, 22, and 23 shown in FIG. 2 are each directly generated from an LED chip, each LED chip has a monochromatic peak, so that uniform white light is emitted. Thus, it is difficult to carry out diffusion color mixing, and therefore, 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 The emission spectrum 22 from the excited phosphor 13 is used. For this reason, it is easier to perform diffuse color mixing than in the case where each of the emission spectra 21, 22, and 23 is directly generated from each LED chip, and as a result, it is possible to perform white light emission in which color unevenness is prevented or suppressed. Becomes possible.

The blue LED chip 11, the phosphor 13, and the red LED chip 12 can be characterized by emission peak wavelengths of emission spectra 21, 22, and 23, respectively, which emit light. The blue LED chip 11 has, for example, an emission peak wavelength of 500 nm or less, and the red LED chip 12 has, for example, an emission peak wavelength of 600 nm or more. In addition, as the blue LED chip 11, for example, a blue-green LED chip having an emission peak wavelength of 540 nm or less can be used. In this specification, the “blue LED chip (blue light emitting LED element)” includes the “blue green LED chip (blue light emitting LED element)”. When a blue-green LED chip is used, a configuration may be adopted in which a phosphor that emits light when excited by the blue-green LED chip is 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. When the phosphor 13 is a green light-emitting phosphor, the phosphor 13 has an emission peak wavelength between 480 and 560 nm, preferably between 500 and 560 nm.

(3) As shown in FIG. 3, when the emission spectrum 22 is broad, for example, a clear emission peak does not always need to exist between the emission spectra 21 (B) and 23 (R). When a clear emission peak wavelength does not exist in the phosphor 13, the light emission of the phosphor 13 assumes 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, for example, between the emission peak wavelengths of the emission spectra 21 (B) and 23 (R) (for example, the midpoint).

Refer to FIG. 1 again. The white light emitting LED lamp 100 shown in FIG. 1 includes a blue LED chip 11, a red LED chip 12, and a phosphor 13 as an integrated element. More specifically, the blue LED chip 11 and the red LED chip 12 are both arranged on a dish-shaped (or cup-shaped) pedestal 17 formed as a part of the lead frame 14. A phosphor 13 is formed on a pedestal (pedestal) 17 so as to cover the red LED chip 12. In addition, since it is sufficient that the phosphor 13 emits light by the blue LED chip 11, the phosphor 13 may cover a part of the blue LED chip 11 and the red LED chip 12. The structure which does not cover 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 a bonding wire 15. And is 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, and the upper end thereof 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 serving as electrodes of the LED are provided above and below the LED bare chip is not limited to this, and the anode and the cathode may be provided on one surface of the LED bare chip. Good. The LED bare chip can be manufactured by a known method, for example, by growing a light emitting layer of an LED on a substrate. In this embodiment, the LED chips are electrically connected by wire bonding. However, the present invention is not limited to this, and the LED chips may be flip-chip mounted. In this case, a configuration in which the bonding wire 15 does not exist can be adopted.

The lead frame 14 is electrically connected to an unillustrated external circuit (for example, a lighting circuit). 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. Will be 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.

The base 17 on which the blue LED chip 11 and the red LED chip 12 are arranged, the bonding wire 15 and a part of the lead frame 14 are sealed by a shell-shaped transparent resin portion 16. , Made of epoxy resin or silicone resin. The shape of the transparent resin portion 16 is not limited to a shell shape, and may be, for example, an SMD (Surface Mount Device) chip type (such as a rectangular parallelepiped type).

In the integrated element type (one-element type) LED lamp 100 shown in FIG. 1, a 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. When both of them (11 and 12) are thermally coupled, they can be used at almost the same temperature, so that control of element temperature characteristics can be simplified. That is, when the blue LED chip 11 and the red LED chip 12 are respectively arranged and operated on separate tables using four leads without using the common lead 14a, the semiconductor element Since certain LED chips 11 and 12 have temperature dependence 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. By thermally coupling the LED chip 12 and the common table 17 to each other, temperature compensation for operation can be easily performed. The configuration shown in FIG. 1 can reduce the number of leads (leads) than the configuration using four leads, so that the manufacturing cost of the lamp can be reduced.

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 without using the common lead 14a. Further, if the blue LED chip 11 and the red LED chip 12 have the same forward current direction and are electrically connected in series, the number of leads can be reduced to a minimum of two. is there.

Further, since the LED lamp 100 is an integral element type, the dimensions of the lamp can be made relatively small. Further, 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, so that the light emitted from the blue LED chip 11 and the red LED chip 12 is The body 13 can scatter and diffuse. For this reason, it is possible to more effectively reduce the light mixing unevenness during the light mixing illumination. 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 degree of color mixture unevenness occurs. In the LED lamp 100, the light emission from each LED chip passes through the phosphor 13. In this case, the light is scattered, diffused, and mixed, so that white light with reduced mixed color unevenness is obtained. Further, for the purpose of reducing uneven color mixture, for example, the surface of the transparent resin portion 16 may be made uneven to further diffuse and diffuse.

FIG. 4 shows an example of the actual emission spectrum distribution of 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 phosphor 13 (emission peak wavelength: 570 nm, peak emission intensity: In addition to about 20), an 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, the insufficient spectral power of red light emission when the phosphor is excited by the blue LED chip in the related art can be compensated.

Further, since the spectral power of the red light emission is supplemented by the light emission of the red LED chip 12, an LED lamp having a higher luminous efficiency than a case where the same red light emitting spectral power is supplemented by a red light emitting phosphor. Can be provided. As described above, the emission peak wavelength of the red LED chip 12 may be 580 nm or more, but the color reproduction characteristic (color reproducibility) for vividly displaying colors is such that the emission wavelength peak of the red LED chip 12 is 600 nm or more. , The stimulus purity of the photoreceptor cells against the L-cone (receptor cells that respond to the stimulus corresponding to red) is increased, so that the photoreceptors are particularly excellent. Therefore, the emission peak wavelength is preferably set to 600 nm or more.

At present, 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-based) is used. It is advantageous to supplement the red component with a GaAlAs-based red LED chip. Of course, an AlInGaP-based LED chip which 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 which is insufficient in the conventional configuration can be easily introduced.

In the LED lamp 100 of the present embodiment, the red light emission spectral power is provided by the light emission of the red LED chip 12, so that the red light emission spectral power can be electrically controlled. Therefore, the intensity of the red emission spectrum can be easily adjusted, and as a result, a variable color temperature light source can be provided 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, which 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. 5 (a) to (d), the intensity of the red emission spectrum 23 increases. As the intensity of the red emission spectrum 23 increases, the correlated color temperature of the LED lamp 100 decreases. That is, by adjusting the intensity of the red light emission spectrum 23, the light color of the LED lamp 100 can be arbitrarily changed. Therefore, for example, light colors having various correlated color temperatures such as daylight, daylight white, white, warm white, and bulb color can be obtained.

The variable light color LED lamp can be realized, for example, by configuring the LED lamp 100 of the present embodiment with the circuit configuration shown in FIG. The circuit 200 shown in FIG. 6 includes a blue LED chip 11, a light emission intensity adjusting unit (light emission intensity controller) 11 a for adjusting the light emission intensity of the blue LED chip 11, a red LED chip 12, and light emission of the red LED chip 12. A light intensity adjusting means (light 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. Further, 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 between the blue LED chip 11 and the red LED chip 12, the emission intensity adjusting means 11a connected to the blue LED chip 11 simply has Even if a variable resistor is used only for the light emission intensity adjusting means 12a connected to the red LED chip 12 using a fixed resistor, a light color variable LED lamp can be realized. The light emission intensity adjusting means is not limited to a variable resistor, but means for switching a fixed resistance, means for using a ladder resistor, means for frequency control, means for time division lighting, means for changing the number of connected LED elements as a load. Alternatively, means for switching the connection method can be used. If the light emission intensity ratio between 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 changed. You may make it the structure which changes intensity | strength.

FIG. 7 shows the chromaticity of the LED lamp 100 of the present embodiment. 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 with reference to FIG. 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, it is preferable that the following formula, when a is small and b is large, becomes a phosphor having a strong green tint and enhances luminous efficiency.
_{YAG = (Y 1-a,} Gd a) 3 (Al 1-b, Ga b) 5 O 12: Ce

領域 An area 41 in FIG. 7 is the chromaticity of the blue LED chip 11, and the blue LED chip 11 has a light emission peak near 440 to 480 nm. Curve 42 is the chromaticity of the yellow light emitting phosphor (YAG phosphor) 13. As the a in the composition of the YAG phosphor 13 decreases and the b increases, y increases on the chromaticity coordinates in FIG. 7 and x decreases. Since the YAG phosphor 13 has an excitation spectrum peak near 440 to 480 nm, the YAG phosphor 13 is excited with high efficiency by the blue LED chip 11 having a range of emitted light colors in the region 41.

The chromaticity of the 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, even within the range 45, the closer to the curve 42 the emitted light color is, the lower the output of the blue LED chip 11 itself, which is the excitation source, is. In order to obtain the range, it is preferable to set a color temperature variable range in a chromaticity range located between the area 41 and the curve 42 in the range 45. The chromaticity range 44 of the red LED chip 12 to be mixed with the chromaticity of white light emission in such a range is near 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 correlated color temperature range, the chromaticity of white light emitted by the blue LED chip 11 and the yellow light emitting phosphor 13 is It is desirable to be located above the radiation trajectory 30 and within a range 43 having a high correlated color temperature.

As a result, in the chromaticity range surrounded by the chromaticity of white light emission in the range 43 and the chromaticity of the red LED chip 12 in the range 44 (that is, the area between the lines 31 and 32 in the drawing). An LED lamp that can change the correlated color temperature can be realized. In other words, the emission color (JIS; daylight, daylight white, white, warm white, light bulb color, CIE; Daylight, Cool) conforming to the chromaticity range of the light source color of the fluorescent lamp specified by JIS or CIE (International Commission on Illumination). white, White, and Warm @ white), and in addition, it is possible to realize an LED lamp with a variable light color that can make the chromaticity of a region connecting the chromaticity ranges of the emission colors. 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 black body 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 trajectory of the light color change follows the blackbody radiation trajectory. The light color can be changed in the vicinity of the radiation trajectory 30. As a result, it is possible to increase the average color rendering index.

In addition, if it is intended to be used as a low color temperature light source without aiming to vary the correlated color temperature in a wide range, the chromaticity of white light emission within the range 43 by the blue LED chip 11 and the yellow light emitting phosphor 13 The range surrounded by the chromaticity of the red LED chip 44 and 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 the 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 emits green light when excited by the blue LED chip 11 is used. Is also possible. The green light-emitting phosphor has an emission peak wavelength of, for example, 480 to 560 nm, and the green light-emitting phosphor is, for example, a YAG phosphor, or at least one of Tb, Ce, Eu, and Mn. A doped phosphor can be used as the emission center. Note that a plurality of types of phosphors having different emission peak wavelengths can be used in order to improve color rendering properties as illumination light. 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 emitted in the vicinity with the light emitted by the phosphor has great significance. Further, in the above embodiment, the case where the inorganic phosphor is used is described, but an organic phosphor having a similar emission peak may be used instead of the inorganic phosphor. This is because practical organic phosphors have been researched and developed in recent years along with the development of the organic EL, so that not only inorganic phosphors but also organic phosphors can be used.

Similarly to the yellow light-emitting phosphor, the light-emitting intensity of the green light-emitting phosphor is basically correlated with the light-emitting intensity of the blue LED chip 11, which is its excitation source. An arbitrary light color can be obtained only by setting the light 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.

At present, there is no industrially practical, high-efficiency green light-emitting LED element having an emission spectrum in the band near 555 nm, which is the highest in human relative luminous efficiency. The realization of high efficiency by light emission of the body has a great advantage.

Further, in the case of the configuration using the green light emitting phosphor, the respective 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 band of RGB. It is possible to do. Therefore, for example, a light source having a large color gamut area ratio and exhibiting vivid color reproduction characteristics, such as a three-wavelength band light 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 stimulus 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 using a green light-emitting phosphor, 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 from the viewpoint of the color rendering of the illumination light. And the peak emission wavelength of the red LED chip 12 is desirably 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 is The wavelength is preferably 610 nm or more, more preferably 630 nm or more.

(Embodiment 2)
In the present embodiment, a preferred 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 light emission spectrum which was insufficient in white light emission by the conventional LED element. Can be provided. A problem in evaluating the color reproducibility of the LED lamp is a method for evaluating the color reproducibility. Hereinafter, this problem will be described.

In the LED lamp 100 of the first embodiment, since the red light emission spectrum, which has been lacking conventionally, is introduced, the special color rendering index R9 and the average color rendering index Ra indicating the appearance of red are improved as compared with the conventional white LED lamp. It is easy to understand. However, it is not appropriate to determine the color reproducibility of the LED lamp only by the evaluation method based on these evaluation numbers. That is, compared to the fluorescent lamps, light bulbs, and HID light sources that have conventionally been used as illumination light sources, the LED light emission has a tendency to show colors very vividly. The evaluation using only the color rendering index and the special color rendering index does not sufficiently capture the characteristics of the color rendering properties when an LED is used as a light source. It is a characteristic phenomenon when LEDs are used for lighting that the emission of the LEDs makes the colors look very vivid, and the spectral distribution of high color purity in a narrow band with a narrow half-value width and no side emission wavelength is obtained. This is due to the characteristic of the LED having the LED.

The LED lamp 100 of the first embodiment emits light with a narrow half-width of the LED in blue on the short wavelength side and red in the long wavelength side in the visible light emission band (see FIG. 4). Therefore, compared to a light source such as a fluorescent lamp, it is possible to show colors very vividly. The inventor of the present application has succeeded in deriving a spectral distribution suitable for the LED lamp 100 under many experiments and studies. Hereinafter, a method of optimizing the color reproducibility of the LED lamp 100 performed by the inventor of the present application 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 using the conventional color rendering property evaluation number will be described. The conventional color rendering property evaluation number is an evaluation to be evaluated when the color reproduction of various color rendering evaluation color chips with a reference light source such as synthetic daylight or black body radiation having a correlated color temperature equivalent to the light source to be evaluated is set to 100. It evaluates how much the color reproduction of various color rendering evaluation color chips at the light source deviates from the color reproduction at the reference light source and makes it an index. Therefore, the highest evaluation is obtained when the color rendering at the evaluation light source matches the color rendering at the reference light source. When the evaluation color chip looks duller than the color rendering with the reference light source, as a result, if it looks unfavorable, the color rendering evaluation is naturally lower, but conversely, the evaluation color patch looks more vivid than the color rendering with the reference light source, As a result, the color rendering evaluation is low even when it looks favorable. In other words, there is a problem that the color rendering evaluation is low even when the image looks more vivid or the color is more conspicuous.

In today's daily life, objects surrounding humans are not only natural objects of medium saturation such as trees and stones, but also industrial products with artificially vivid colors such as vivid blue and yellow. Overflowing. For this reason, if the evaluation color chip looks more vivid 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, an optimization method performed by the present inventors will be described.

The method of evaluating the color rendering properties of light sources has international consistency and is disclosed in Japan in JIS Z8726. Among them, although not specified in the international standard, a method based on a color gamut area ratio is generally shown as an authorized method as "a method for evaluating color rendering properties other than the color rendering index". This method is a method in which the evaluation is made based on the ratio of the color gamut areas composed of 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 obtained by connecting eight points on the chromaticity coordinates rendered by the reference light source. This is an evaluation method in which a ratio between an upper area and an area on chromaticity coordinates when eight points on chromaticity coordinates rendered by an evaluation light source are connected is determined, and the obtained ratio is defined as a color gamut area ratio Ga.

According to this evaluation method, when Ga is smaller than 100, the color has a reduced color appearance, so that it tends to look dull. On the other hand, when Ga is larger than 100, the color has a higher color appearance. And tend 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 that shows a favorable viewing tendency even when Ra is low when the image is 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 increases when Ga is increased, but Ra evaluated using a similar evaluation test color decreases, and discomfort due to a shift in color reproduction from the reference light source increases. Would. 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 indexes for vivid red, yellow, green, and blue, as a new evaluation index. Explaining the evaluation method using this evaluation index, the calculation method shown in JISZ8726 similar to Ga using the above-described evaluation test colors R1 to R8 is hijacked, and R9 to R12 are substituted for the evaluation test colors R1 to R8. This is a method of obtaining a color gamut area ratio using the above. Hereinafter, in this specification, the color gamut area ratio based on the special color rendering indexes R9 to R12 is referred to as “Ga4”.

R1 to R8 were originally selected to evaluate subtle differences in the appearance of natural objects, and are medium-saturation test colors. On the other hand, R9 to R12 are evaluation color chips that are originally selected to evaluate the appearance of vivid objects. For this reason, by using Ga4, it is possible to extract and accurately evaluate whether an object that one wishes to show vividly is clearly visible. In other words, with respect to the appearance of an object requiring a delicate and accurate color appearance of medium saturation, color reproduction faithful to the color of a natural object such that Ga and Ra are close to 100 is performed, and at the same time, With regard to the appearance of an object for which color reproduction is to be performed, performing colorful color reproduction such that Ga4 is high is optimization of color reproduction. When such optimization is performed, more natural color reproduction can be performed while enhancing the contrast of color saturation and enhancing sharpness.

発 明 The inventor of the present application performed optimization processing on the LED lamp 100 of 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. When the thickness is in the range from 610 nm to 630 nm, Ga4 can be increased while Ra is increased, and Ga4 can be made higher than Ga. In other words, within this range, it is possible to faithfully reproduce the color of medium saturation where subtle and strict color reproduction is desired, and vividly reproduce the color of high saturation.

(4) When the emission peak wavelength of the blue LED chip 11 is 470 nm or less, Ra can be increased. When the thickness is in the range of 450 nm to 470 nm, Ga4 can be increased while Ra is increased, and Ga4 can be made higher than Ga.

(4) 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 5000K 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 blackbody radiation, the emission peak wavelength of the red LED chip 12 is in the range of 615 nm to 650 nm; Further, 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 , 620 nm to 630 nm, and the emission peak wavelength of the phosphor 13 is more preferably in the range of 540 nm to 550 nm.

FIGS. 8 to 10 and Tables 1 to 3 show examples of the LED lamp 100 in which the color reproduction has been optimized.

FIG. 8A shows an example of the spectral distribution of the LED lamp 100 that has been optimized for 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 black body 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 a color gamut area ratio by Ga for the LED lamp 100 having the spectral distribution shown in FIG. 8A, and FIG. 8C is a color gamut area by Ga4. It is a graph which shows a ratio. In Table 1 below, in addition to the above conditions, the chromaticity values (x, y), Duv, color rendering (Ra, R1 to R15), and color gamut area ratio of the light color of the LED lamp 100 in FIG. Is shown.

同 様 Similar to FIG. 8A, FIG. 9A shows an example of the spectral distribution of the LED lamp 100 optimized for 5000 K as a representative of the medium having a correlated color temperature. 5000K is a point at which the reference light source to be compared switches from blackbody 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. Similarly to Table 1, in addition to the above conditions, Table 2 below shows the chromaticity values (x, y), Duv, color rendering (Ra, R1 to R15) of the light color of the LED lamp 100 in FIG. The gamut area ratio is also shown.

FIG. 10A shows an example of the spectral distribution of the LED lamp 100 optimized for the case where the correlated color temperature is 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, when calculating Ra, the reference light source to be compared 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. Similarly to Table 1, Table 3 below includes, in addition to the above conditions, the chromaticity values (x, y), Duv, color rendering properties (Ra, R1 to R15) of the light color of the LED lamp 100 in FIG. The gamut area ratio is also shown.

代表 Representative examples of patterns examined by the present inventor in optimizing the combination of the blue LED chip 11, the red LED chip 12, and the phosphor 13 are shown in FIGS. In the figure, 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 an actual measurement or a simulation result. At each point (circle, triangle, square) in the figure, a study is performed as shown in FIGS. 8A to 8C and Table 1.

11 (a) to 11 (c) 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 3000 K, 5000 K, and 6700 K, 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 show examples of correlated color temperatures of 3000 K, 5000 K, and 6700 K, respectively, and the emission peak wavelength of the blue LED chip 11 is fixed at 470 nm.

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

In JIS, a high color rendering three-wavelength band fluorescent lamp is specified as Ra80 or more. When designing the LED lamp 100 with the aim of high color rendering of Ra 80 or more, considering the above results, the range in which the average color rendering index is increased is the range where the emission peak of the red LED chip 12 is 600 nm or more. Was. With such a range, the LED lamp 100 having Ra of 80 or more can be realized. In particular, a point where the average color rendering index is high or a preferable range where the average color rendering index tends to be saturated is a case where 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-saturated colors for which subtle and strict color reproduction is desired. In addition, the LED lamp 100 has a short wavelength in the visible light emission band. Since the half-width is narrow and the spectrum of the LED having high purity is provided on both the side and the long wavelength side, a vivid color reproduction can be performed for a high chroma color. That is, in addition to the height of Ra, a contrast is provided with respect to the saturation, that is, it is possible to realize a preferable visual environment having a sharp color.

範 囲 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. The inventor of the present application has confirmed by experiment that if the emission peak wavelength is longer than this, it becomes difficult to realize the LED lamp 100 having a particularly high correlated color temperature, and it becomes difficult for Ra to exceed 80. In addition, when it exceeds 470 nm, it was found that the combination range of the emission peaks of the red LED chip 12 that can increase Ra is narrowed even if the LED lamp 100 having a low correlated color temperature is to be realized. 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 the wavelength is less than 450 nm, it becomes difficult for Ra to exceed 90, and in particular, when the LED lamp 100 having a high correlated color temperature is realized, the band of the emission wavelength of the phosphor 13 that can be combined is further restricted. It is.

検 討 Considering the luminous efficiency, the following can be said. If the emission peak wavelength of the red LED chip 12 is out of the range of 610 nm to 630 nm, the luminous efficiency (lm / W) decreases. Therefore, from the viewpoint of the luminous efficiency, it is preferable that the luminous efficiency be in the range of 610 nm to 630 nm. Further, if the emission peak wavelength of the blue LED chip 11 is also less than 450 nm, the luminous efficiency (lm / W) is reduced. Therefore, similarly to the red LED lamp 12, the blue LED lamp 11 is preferably 450 nm or more. .

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

Furthermore, the following was also found. 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 range of the emission peak of the blue LED chip 11 is changed from 455 nm to 465 nm, the emission peak of the red LED chip 12 is changed from 620 nm to 630 nm, and the range of the emission peak of the phosphor 13 is changed from 540 nm. Preferably it is 550 nm.

場合 Considering the case where the light source capable of greatly changing the light color is not specialized but the realization of high color rendering of Ra90 or more at various correlated color temperatures is considered, the following can be said. The high color rendering of Ra 90 or higher is color rendering group 1A (Ra ≧ 90) in the CIE color rendering category, and is of a level that can be sufficiently used for applications requiring 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 is The range is from 450 nm to 460 nm, and more desirably, the peak wavelength of the combined phosphor should be from 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 blackbody radiation, the emission peak of the red LED chip 12 is from 615 nm to 650 nm, and the peak wavelength of the combined phosphor is from 545 nm to 560 nm. I just need.

Furthermore, particularly excellent examples in the range where Ra and Ga are high and Ga4 is high are the combination examples shown in FIGS. It should be noted that even if each emission peak wavelength of the combination is slightly shifted (for example, about ± 5 to 10 nm), those skilled in the art can realize an LED lamp 100 with high Ra and Ga and high Ga4. Easily understandable.

When the correlated color temperature is relatively low (for example, 3000K), 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 is The wavelength is in the range of 545 nm. Within 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 medium (for example, 5000K), 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 is The wavelength is in the range of 545 nm. Within this range, the LED lamp 100 having Ra = 94.3, Ga = 101.6, and Ga4 = 1112.9 can be realized.

When the correlated color temperature is relatively high (for example, 6700K), 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 is The wavelength is in the range of 545 nm. Within this range, the LED lamp 100 with Ra = 92.2, Ga = 96.6, and Ga4 = 107.5 can be realized.

In the LED lamp of the present embodiment, the optimization of Ga and Ga4 has been studied for the range where Ra is high, so that the distribution of the color reproduction of each test color has little distortion and the colors are more vivid. It becomes a visible light source. That is, since the vivid red / yellow / green / blue test colors R9 to R12 used for the special color rendering index are test color chips representing artificial vivid colors, Ra (and Ga) are Under high conditions, maximizing Ga4 constituted by this test color chart can realize a light source that renders only vivid colors more vividly while natural colors look more natural. Since the spectral reflectance of these brightly colored objects generally shows a sharp change in spectral distribution at a specific wavelength, a light-emitting diode having a narrow half-value width of the spectral distribution can be suitably used. As a result, natural objects can be reproduced more naturally, and objects with artificially vivid colors can be reproduced more vividly. Become.

If the focus is on making the colors look more vivid, the range in which such an LED lamp can be realized is even wider than the range described above because Ra does not have to be made higher than necessary. .

(Embodiment 3)
An 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 configured by one blue LED bare chip 11 and one red LED bare chip 12, that is, a total of two LED bare chips. However, in the present 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 a light emitting portion. This is different from the LED lamp 100 of the first embodiment. The other points are the same as in the first embodiment, and therefore, the description of the same points as in the first embodiment will be omitted or simplified for simplification of the description. It is needless to say that 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 the present embodiment, since one LED bare chip that emits two luminescent colors is used, the following advantages are obtained as compared with the first embodiment in which the bare chips of two luminescent colors have to be arranged side by side. That is, since only one LED bare chip is used, the light emission positions of both red and blue are almost the same on one LED bare chip. As a result, an LED lamp that is more advantageous for color mixing can be realized. Further, since both the red light emitting portion and the blue light emitting portion are more thermally bonded, the temperature between the two light emitting portions is made uniform. As a result, since both can be regarded as being thermally the same, 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 light will be described with reference to FIGS.

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

Next, as shown in FIG. 14B, the substrate 115 is peeled 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 method such as polishing of the substrate 115, mechanical separation, removal of the substrate 115 by etching, separation by thermal stress, or the like 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 emission colors is provided. Is obtained. As described above, after the light emitting layer of the blue LED and / or the red LED are peeled off, they are laminated to form one LED bare chip.

組 み 合 わ せ Hereinafter, a combination pattern of bonding will be exemplified with reference to FIGS. Although there are many variations of this bonding, main patterns are shown below. Note that, 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 this structure, one electrode may be provided on the upper surface of the upper blue LED light emitting layer 111 with the substrate 115 interposed, and one electrode may be provided on the lower surface of the lower red LED light emitting layer 112.

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

FIG. 16B shows an example in which, when the substrate 115 is conductive, LED light emitting layers of a double-sided electrode and a single-sided electrode are stacked on one side of the substrate 115. In this structure, one electrode may be provided on the upper surface of the substrate 115, and two electrodes may be provided 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 light of a short wavelength disposed below the substrate 115, and light from the LED light-emitting layer 111 that emits light of the short wavelength. 1 shows a structure in which an LED active layer (red LED active layer) 112 ′ that is excited and emits light is disposed on the upper side. 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 the variations of the LED light emitting layer for each emission color, FIGS. 15 (c) and 16 (a) to (c) In the structure shown in (1), there is also an inverted pattern for the vertical relationship.

(4) Instead of laminating the LED light emitting layers (111, 112) on one or both sides of the same substrate 115, a structure in which the LED light emitting layers (111, 112) are spatially juxtaposed on the same substrate 115 is also possible. FIGS. 17 and 18 show examples of such a structure.

FIG. 17A shows a structure in which the LED light emitting layers (111, 112) of each color are formed on one conductive substrate 115. In this structure, one common electrode may be provided below 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 each color are formed on one non-conductive 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. 17B is inverted.

FIG. 18A shows a structure in which the LED light emitting layers (111, 112) of each color are formed on one conductive substrate 115. In the case of this structure, one common electrode is provided under the substrate 115, 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. Provided and mixed.

FIG. 18B shows a structure in which LED light emitting layers are juxtaposed as they are. In the case of this structure, the substrate 115 becomes unnecessary, and the bonding process shown in FIG.

FIG. 18 (c) shows a structure in which two LED light emitting layers of the double-sided electrode are directly laminated. Even in the case of this structure, the substrate 115 becomes unnecessary. In addition, in the case of this concept, there may be a variation in which the LED light emitting layers of the single-sided electrode and the double-sided electrode are stacked, and a variation in which four LED light-emitting layers are stacked.

The structure shown in FIGS. 17 and 18 is also an example of many possible combinations, and includes not only the variations of the LED light emitting layer of each emission color but also FIGS. 17 (a), 18 (a) and (b). There is also an inverted pattern of the vertical relationship of the structure shown in FIG.

In the present embodiment, 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 have a structure integrally formed as one LED chip. As it approaches, it becomes more advantageous for color mixing. Furthermore, since both are more thermally joined, 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)
Embodiment 4 An LED lamp 500 according to Embodiment 4 of the present invention will be described with reference to FIG. FIG. 19 schematically shows a configuration of the LED lamp 500. The LED lamp 100 according to the first embodiment has an integrated element configuration, whereas the LED lamp 500 according to the present embodiment has a cluster configuration instead of an integrated element configuration. In the following, for the sake of simplicity, different points from the first embodiment will be mainly described, and description of the same points as the first embodiment will be omitted or simplified.

As shown in FIG. 19, the LED lamp 500 of the present embodiment includes a white light emitting LED element 52 including 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 the light-emitting elements 12 are clustered in a plane. 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 that covers 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 a 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, for example, alternately.

In the LED lamp 500 of the present embodiment, since the white light-emitting LED element 52 and the red light-emitting LED element 54 having different constituent materials can be individually formed and then clustered into one lamp unit, the design of each LED element is It can be individually and optimally designed. In addition, since good LED elements can be selected and clustered into one lamp unit, it is possible to improve the industrial yield. Further, there is an advantage that the heat radiation design becomes easy.

Further, even when the output light flux of the blue LED chip 11 and the output light flux of the red LED chip 12 are different, since each LED chip is configured as an individual element, 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 the present embodiment increases the degree of freedom in lamp design, as compared to clustering elements in which the blue LED chip 11 and the red LED chip 12 are pre-installed at a fixed ratio in one element. Can be.

In the case of the LED lamp 500, the LED chips 52 and 54 of the respective light colors serving as light emission sources emit light at spatially separated locations as individual elements. As compared with the case where an integrated element is formed as described above, the uneven light mixing tends to be large. For the purpose of reducing such color mixture unevenness, an LED lamp 600 having a three-dimensional cluster configuration as shown in FIG. 20 may be used.

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 excited by the blue LED chip 11 to emit light, and a red light emitting LED element 64 including a red LED chip 12. The white light emitting LED elements 62 and the red light emitting LED elements 64 are arranged at different heights. According to the LED lamp 600, since the individual elements 62 and 64 are three-dimensionally arranged, the light output from the LED elements 62 and 64 can be reflected and refracted from each other. It becomes possible to reduce. Note that the LED lamp 600 is configured such that a bullet-shaped LED element 62 having a relatively narrow light distribution characteristic and a rectangular LED element 64 having a relatively wide light distribution characteristic are combined to further improve the light mixing characteristic. are doing.

As described in the first embodiment, the LED lamps 500 and 600 are configured so that the 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, it is also possible to make a light color variable LED lamp. It is also possible to use a green light emitting phosphor instead of the yellow light emitting phosphor 13. In this case, a blue-green light emitting LED element 52 (or 62) combining a blue LED chip 11 and a green light emitting phosphor excited by the blue LED chip 11 to emit light, and a red light emitting LED element 54 having a red LED chip 12 (or 64) may be configured as a cluster to form the LED lamp 500 (or 600).

In the above embodiment, a GaN-based blue LED chip (a GaN-based LED includes not only GaN but also AlInGaN and InGaN) is used as the blue light-emitting LED element (blue LED chip) 11 and yellow light-emitting fluorescent light is used. Although it was used in combination with a body, the present invention is not limited to this, and a ZnSe-based blue light-emitting LED element (ZnSe-based blue LED chip) may be used. A configuration in which yellow fluorescent light is emitted to form a white light emitting LED element can also be adopted. In this case, the ZnSe substrate becomes the phosphor.

(Embodiment 5)
The LED lamp in the above embodiment can be used as a lamp unit in combination with a power supply that supplies power to the LED lamp. FIG. 21 schematically shows a 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 supply 120 that supplies power to the LED lamp 100, and a power supply. And a base 130 connected to the base 120. A plurality of LED lamps 100 can be arranged on the bottom surface of the reflection plate 110, and for example, about 10 to 200 LEDs can be arranged. Further, when the reflection plate 110 is thermally coupled to the LED lamp 100, the reflection plate 110 plays a role of a heat sink, so that it is possible to contribute to the improvement of the heat radiation 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 (luminous flux included in the beam angle) is 60 lm, the lamp life is 10000 hours, and the luminous efficiency is about 30 to 50 lm / W. Confirmed by the inventor. This characteristic is very excellent as compared with the characteristics of a conventional lamp unit combining a halogen bulb, which is not an LED lamp, and a dichroic mirror (beam luminous flux: about 60 lm, life: 2,000 hours, luminous efficiency: about 15 lm / W). You can see that it is. In addition, since the LED lamp 100 attached to the lamp unit 1000 is a semiconductor element, there is no problem such as a bulb being burned out. Therefore, there is also an advantage that handling is easy.

Also, by changing the LED lamp 100 to a variable light color LED lamp, the lamp unit 1000 capable of changing the light color can be provided. In this case, the circuit 200 shown in FIG. The power supply 120 may be provided with, for example, an AC / DC converter. In the example shown in FIG. 21, a variable light color dial 122 and a variable brightness 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. Make up.

Although the present embodiment has been described using the LED lamp 100, the present invention is not limited to this. The LED lamps of the second and third embodiments, and the LED lamp 500 or 600 of the fourth embodiment and the power supply 120 are The 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 according to various uses. Further, it is also possible to adopt a configuration in which about 60 LED lamps 100 are used as one unit, and one unit is used as one light source. Also, a configuration using a plurality of the one unit may be adopted.

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 and the like.

FIG. 2 is a diagram schematically illustrating a configuration of the LED lamp 100 according to the first embodiment. 5 is a graph for schematically explaining a spectral distribution of the LED lamp 100. 5 is a graph for schematically explaining a spectral distribution of the LED lamp 100. 4 is a graph showing an example of a spectral distribution of the LED lamp 100. (A)-(d) is a graph which shows an example when the spectral distribution of the LED lamp 100 is changed. FIG. 3 is a circuit diagram schematically illustrating a circuit 200 that constitutes the variable light color LED lamp. 5 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 optimized at 3000K. (B) is a graph showing a color gamut area ratio by Ga. (C) is a graph showing a color gamut area ratio by Ga4. (A) is a graph which shows the spectral distribution of the LED lamp 100 optimized at 5000K. (B) is a graph showing a color gamut area ratio by Ga. (C) is a graph showing a color gamut area ratio by Ga4. (A) is a graph which shows the spectral distribution of the LED lamp 100 optimized at 6700K. (B) is a graph showing a color gamut area ratio by Ga. (C) is a graph showing a color gamut area ratio by Ga4. (A)-(c) are graphs showing the relationship between the emission peak wavelength (nm) of the red LED chip 12 and Ra. (A)-(c) are graphs showing the relationship between the emission peak wavelength (nm) of the red LED chip 12 and Ra. (A)-(c) are graphs showing the relationship between the emission peak wavelength (nm) of the red LED chip 12 and Ra. (A)-(c) is process sectional drawing for demonstrating the manufacturing 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. FIG. 13 is a diagram schematically illustrating a configuration of an LED lamp according to a fourth embodiment. It is a figure showing typically composition of LED lamp 600 in Embodiment 4. It is a figure which shows the structure of the lamp unit 1000 concerning Embodiment 5 typically.

Explanation of reference numerals

11 Blue light emitting LED element (blue LED chip)
11a Light emission intensity adjusting means (variable resistance)
12. Red light emitting LED element (red LED lamp)
12a Light emission intensity adjusting means (variable resistance)
13 phosphors (yellow light emitting phosphors, green light emitting phosphors)
Reference Signs List 14 lead frame 15 bonding wire 16 transparent resin part 17 pedestal 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 device 122 Variable light color dial 124 Variable brightness dial 130 Base 500 LED lamp 600 LED lamp 1000 Lamp unit

Claims (12)

A blue light emitting LED element,
A red light emitting LED element,
The phosphor excited by the blue light-emitting LED element, and emits light of a wavelength band between a blue wavelength band in which the blue light-emitting LED element emits and a red wavelength band in which the red light-emitting LED element emits light. And a phosphor that emits an emission spectrum that supplements the LED lamp.
When the correlated color temperature of the LED lamp is 5000K or more and the reference light source for color rendering evaluation is synthetic daylight, the peak wavelength of the blue light emitting LED element is in a range of 450 nm to 460 nm, and the red light emitting LED is An LED lamp, wherein a peak wavelength of the element is 600 nm or more, and a peak emission wavelength of the phosphor is in a range of 520 nm to 545 nm. A blue light emitting LED element,
A red light emitting LED element,
The phosphor excited by the blue light-emitting LED element, and emits light of a wavelength band between a blue wavelength band in which the blue light-emitting LED element emits and a red wavelength band in which the red light-emitting LED element emits light. And a phosphor that emits an emission spectrum that supplements the LED lamp.
When the correlated color temperature of the LED lamp is less than 5000 K and the reference light source for color rendering evaluation is blackbody radiation, the peak wavelength of the blue light emitting LED element is in a range of 450 nm to 460 nm, and the red light emitting LED element An LED lamp, wherein a peak wavelength is in a range of 615 nm to 650 nm, and an emission peak wavelength of the phosphor is in a range of 545 nm to 560 nm. The LED lamp according to claim 1, wherein the phosphor is a yellow light-emitting phosphor that emits yellow light when excited by the blue light-emitting LED element. The LED lamp according to claim 3, wherein the yellow light-emitting phosphor is a YAG phosphor or a phosphor having a Mn emission center. The peak wavelength of the red light emitting LED element is in the range of 610 nm to 630 nm,
5. The color gamut area ratio Ga4 composed of R9 to R12, which is a special color rendering index, is higher than the color gamut area ratio Ga composed of R1 to R8, which is the average color rendering index. The LED lamp as described. The LED lamp according to any one of claims 1 to 5, further comprising a light emission intensity adjusting means for adjusting the light emission intensity of the red light emitting LED element. 7. The LED lamp according to claim 6, wherein the light emission intensity adjusting means is a variable resistor. The LED lamp according to any one of claims 1 to 7, wherein the blue light emitting LED element, the red light emitting LED element, and the phosphor are integrally formed. 9. The LED lamp according to claim 8, wherein 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. The LED lamp according to any one of claims 1 to 9, wherein the blue light emitting LED element and the LED element including the phosphor, and the red light emitting LED element are configured in a cluster. A lamp unit comprising: the LED lamp according to any one of claims 1 to 10; and a power supply that supplies power to the LED lamp. The lamp unit according to claim 11, further comprising a reflector that reflects light emitted from the LED lamp.

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