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Publication numberUS20100001297 A1
Publication typeApplication
Application numberUS 12/429,787
Publication dateJan 7, 2010
Filing dateApr 24, 2009
Priority dateApr 24, 2008
Also published asDE102009018568A1, US8624272, US20110297974
Publication number12429787, 429787, US 2010/0001297 A1, US 2010/001297 A1, US 20100001297 A1, US 20100001297A1, US 2010001297 A1, US 2010001297A1, US-A1-20100001297, US-A1-2010001297, US2010/0001297A1, US2010/001297A1, US20100001297 A1, US20100001297A1, US2010001297 A1, US2010001297A1
InventorsJun Takashima, Norio Kanai
Original AssigneeJun Takashima, Norio Kanai
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Led assembly with color temperature correction capability
US 20100001297 A1
Abstract
An illumination assembly is provided which is capable of correcting a color temperature. The assembly generally comprises a substrate and a light emitting device mounted on the substrate that further comprises a light emitting element and a resin containing a phosphor excitable by light emitted from the light emitting element. A reflectance factor of the substrate may be set corresponding to light emitted from the light emitting device, such that the light emitted by the light emitting device complies with a desired light emission for the illumination assembly. A translucent filling resin or translucent coating resin may further be applied on the light emitting device and the substrate, the translucent resin having a refractive index and correspondingly operable to suppress variations in color temperature. The assembly may comprise a plurality of light emitting devices having variable light color temperatures, wherein a plurality of substrate coatings may be provided having reflectance factors corresponding to the associated light color temperatures. One or more translucent resins may be applied on light emitting devices as desired to further suppress variations in color temperature.
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Claims(20)
1. An illumination assembly, comprising:
a substrate;
a light emitting device mounted on the substrate, the light emitting device further comprising a light emitting element, and a resin containing a phosphor excitable by light emitted from the light emitting element; and
a reflectance factor of the substrate set corresponding to light emitted from the light emitting device.
2. The illumination assembly of claim 1, wherein the substrate further comprises:
a base material; and
a coating having color absorbing a particular spectrum of light emitted from the light emitting device,
wherein variations of a color temperature are suppressed.
3. The illumination assembly of claim 2, wherein the light emitting element further comprises an LED chip emitting blue light with a wavelength of approximately 380 to 480 nm, and a phosphor emitting light with a wavelength of approximately 480 to 780 nm by being excited by the blue light; and
wherein the color of the substrate coating is operable to absorb the blue light.
4. The illumination assembly of claim 1, further comprising a translucent resin applied on the light emitting device and the substrate, the translucent resin having a refractive index and correspondingly effective to suppress variations in color temperature.
5. The illumination assembly of claim 4, further comprising a transparent case encompassing the light emitting device, the substrate and the translucent resin applied on the light emitting device and the substrate.
6. The illumination assembly of claim 5, wherein the inside of the case is completely filled with the translucent resin applied on the light emitting device and the substrate.
7. The illumination assembly of claim 4, the translucent resin applied on the light emitting device and the substrate further comprises a pigment absorbing light with a specified wavelength region.
8. The illumination assembly of claim 4, wherein the transparent resin applied on the light emitting device and the substrate further comprises a phosphor exciting light with a specified wavelength region.
9. The illumination assembly of claim 4, wherein the translucent resin applied on the light emitting device and the substrate further comprises both of a pigment absorbing light with a specified wavelength region and a phosphor exciting light with a specified wavelength region, wherein a mixing ratio between the amounts of pigment and phosphor may be adjusted to produce a desired refractive index for the translucent resin.
10. An illuminating assembly the assembly comprising:
a plurality of light emitting devices, each light emitting device further comprising a light emitting element, and a resin containing a phosphor excitable by light emitted from the light emitting element;
a substrate on which the plurality of light emitting devices are mounted, the substrate further comprising a base material, and a plurality of coatings, each coating associated with one of the plurality of light emitting elements; and
a color temperature of each substrate coating set corresponding to light emitted from the associated light emitting device.
11. The assembly of claim 10, the plurality of light emitting elements further comprising a plurality of blue LED chips functional to emit light having a wavelength of approximately 380 to 480 nm, each blue LED chip further sealed with the resin containing a phosphor excitable by the light emitted from the associated blue LED chip.
12. The assembly of claim 11, the plurality of coatings further comprising yellow ink coatings of variable color temperatures, wherein setting higher substrate coating color temperatures corresponds with increasing absorption of blue light emitted from the associated light emitting devices.
13. The assembly of claim 11, further comprising:
a transparent case containing the plurality of light emitting devices and the substrate, and
a plurality of translucent resins filling the inner space of the case, a translucent resin associated with each of the plurality of light emitting devices,
each translucent resin having a refractive index set corresponding to light emitted from the associated light emitting device.
14. The assembly of claim 13, wherein setting lower refractive indices corresponds with increasing absorption of blue light emitted from the associated light emitting devices.
15. An illuminating assembly for suppressing variation of color temperatures in the assembly, the assembly comprising:
a plurality of light emitting devices, each light emitting device further comprising a light emitting element, and a resin further comprising phosphor excitable by light emitted from the light emitting element, a compounding ratio of the phosphor corresponding to a color temperature of the light emitted by the light emitting element;
a substrate on which the plurality of light emitting devices are mounted, the substrate further comprising a plurality of coatings associated with the plurality of light emitting elements mounted thereon; and
one or more translucent coating resins applied to one or more light emitting devices, a refractive index for each translucent coating resin set corresponding to the light emitted from the corresponding light emitting device.
16. The assembly of claim 15, wherein one or more light emitting devices are not coated with a translucent coating resin.
17. The assembly of claim 15, further comprising a color temperature of each substrate coating set corresponding to light emitted from the associated light emitting device.
18. The assembly of claim 17, wherein the one or more translucent coating resins may be applied after setting a color temperature for each substrate coating, wherein variation of color temperatures of light emitted by the plurality of light emitting devices is suppressed.
19. The assembly of claim 15, wherein a color temperature of the light emitted from each of the plurality of light emitting devices is set to be lower than the color temperature required for the illumination device.
20. The assembly of claim 19, wherein each light emitting device further comprises a resin further comprising phosphor excitable by light emitted from the light emitting element,
wherein a compounding ratio of the phosphor corresponds to a color temperature of the light emitted by the light emitting element, the compounding ratio adjustable to set the color temperature of the light emitted from each of the plurality of light emitting devices to be lower than the color temperature required for the illumination device.
Description

A portion of the disclosure of this patent document contains material that is subject to copyright protection. The copyright owner has no objection to the reproduction of the patent document or the patent disclosure, as it appears in the U.S. Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims benefit of the following patent application which is hereby incorporated by reference: Japanese Patent Application No. JP2008-113315 filed Apr. 24, 2008

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

REFERENCE TO SEQUENCE LISTING OR COMPUTER PROGRAM LISTING APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

The present invention relates to an illumination device using a light emitting element such as a light emitting diode (hereinafter referred to as “LED”).

In a conventional illumination device using a light emitting element such as an LED, countermeasures are taken to make it waterproof in consideration of the outdoor installation. At least one waterproofing technique has previously been employed in which a case is filled with a transparent resin.

For example, Japanese Unexamined Patent Publication No. 2005-302483 discloses an illumination device providing: a substrate with an LED mounted thereon; and a transparent and nearly box-shaped case with a back surface formed as an opening, wherein: the substrate is stored in the case from the opening; the substrate is supported with a space provided between the substrate and a front inner wall of the case; a transparent filling material is injected and filled in the case along a following path from the opening to the case; the filling material is cured to fix the substrate and the case integrally; and thus the LED along with the substrate are embedded in the filling material in the case and hermetically sealed, thereby ensuring a sufficient waterproof property. When the LED is lighted, the light is emitted through the transparent filling material and the case.

BRIEF SUMMARY OF THE INVENTION

A white or blue-colored LED used for the purpose of the illumination typically has a structure in which an LED chip that emits blue light (light with wavelength of approximately 380 to 480 nm) is sealed with a resin containing a phosphor (e.g., silicon, epoxy). The conversion to a desired color of light is performed by means of the light with a wavelength region of approximately 480 to 780 nm that is converted by exciting the phosphor by the blue light emitted from the LED chip, and blue light that passes through the resin without being converted. Also, in the conversion to a desired color of light, the color of light is adjusted by, for example, changing a mixing ratio of the phosphor in the case where a top surface of the sealing resin containing the phosphor is an air layer. It is not premised on filling the top surface of the sealing resin containing the phosphor with the transparent resin (e.g., silicon).

When the case that stores the LED is filled with translucent silicon for the purpose of waterproofing, a refractive index of the sealing resin for the LED is almost equal to that of the silicon to be filled for the purpose of waterproofing. Therefore, there is a problem that the color temperature significantly shifts to a side of high color temperature due to a difference of the ratio between the light converted by exciting the phosphor by the blue light emitted from the LED chip, and the blue light that passes through without being converted, as compared to the case where the top surface of the sealing resin containing the phosphor is the air layer. An increase of the ratio of the blue light makes a white LED appear to be bluish white, and a bulb-colored LED appear to be yellowish white.

In view of the foregoing, an object of the present invention is to provide an illumination device capable of correcting the color temperature. In light of this object, an LED assembly with color correcting substrate in various embodiments may comprise one or more of the following aspects.

According to a first aspect of the LED assembly with color correcting substrate herein disclosed, in order to solve the problems described above, an illumination device as shown in FIG. 1 is provided with: a light emitting device (an LED 1) including at least a light emitting element (for example an LED chip 5), and a resin (a sealing resin 6) containing a phosphor excited by light emitted from the light emitting element; a substrate 2 providing the light emitting device mounted thereon; and a translucent resin (a filling resin 4) applied on the light emitting device 1 and the substrate 2, wherein: a reflectance factor of the substrate 2 is set corresponding to light emitted from the light emitting device 1.

In a second aspect of the LED assembly, the LED assembly is provided with the light emitting device (the LED 1), the substrate 2, and a case 3 for storing the resin 4 applied on the light emitting device (the LED 1) and the substrate 2.

In a third aspect of the LED assembly, the setting of the reflectance factor of the substrate 2 is to set the color of the substrate surface so as to suppress the change of the color temperature before and after applying the transparent resin 4.

In a fourth aspect of the LED assembly, an LED chip 5 is used as the light emitting element.

In a fifth aspect of the LED assembly, a plurality of LED chips is included.

In a sixth aspect of the LED assembly, each of the plurality of LED chips falls into various types having a different light spectra from each other.

In a seventh aspect of the LED assembly, the light emitting device uses an LED chip 5 emitting blue light with wavelength of approximately 380 to 480 nm, a phosphor emits light with a wavelength region of approximately 480 to 780 nm by being excited by the blue light; and the color of the substrate surface is color absorbing the blue light.

In an eighth aspect of the LED assembly, a coating 8 having the color absorbing the blue light is applied on the substrate surface, as shown in FIG. 1.

In a ninth aspect of the LED assembly, the transparent resin 4 to be applied on the light emitting device and the substrate 2 contains a pigment 9 absorbing light with a specified wavelength, as shown in FIG. 4.

In a tenth aspect of the LED assembly, the transparent resin 4 to be applied on the light emitting device and the substrate 2 contains a phosphor 10 exciting light with a specified wavelength, as shown in FIG. 5.

In an eleventh aspect of the LED assembly, a plurality of light emitting devices (LEDs 1) is included, as shown in FIGS. 6 and 7.

In a twelfth aspect of the LED assembly, the color temperature is set lower for the substrate surface provided the light emitting device mounted thereon with higher color temperature, upon the plurality of light emitting devices 1 a, 1 b and 1 c having the different color temperatures from one another (FIG. 6).

In a thirteenth aspect of the LED assembly, the resin having a lower refractive index is applied to the light emitting device with higher color temperature, and to the periphery of the substrate providing such light emitting device mounted thereon, upon the plurality of light emitting devices having the different color temperatures from one another (FIG. 6).

In a fourteenth aspect of the LED assembly, the inside of the case 3 is completely filled with the translucent resin 4 applied on the light emitting device (the LED 1) and the substrate 2.

In a fifteenth aspect of the LED assembly, the color temperature of the light emitted from the light emitting device is set to be lower than the color temperature required for the illumination device.

In an illumination device according to a preferred embodiment of the disclosed LED assembly, a light emitting device in which a light emitting device is sealed with a resin containing a phosphor is mounted on a substrate, and a translucent resin is applied to the light emitting device and the substrate. A reflectance factor of the substrate is set corresponding to the light emitted from the light emitting device, so that the color temperature can be readily corrected at low cost by changing the reflectance factor of the substrate even if the emission color deviates from the desired color temperature due to the relationship between a refractive index of a resin sealing the light emitting element and that of a resin containing the sealing resin which fills the light emitting device and the substrate.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a structure according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a structure according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a structure according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a structure according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a structure according to a fifth embodiment of the present invention.

FIG. 6 is a cross-sectional view showing a structure according to a sixth embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a structure according to a seventh embodiment of the present invention.

FIG. 8 is an explanatory diagram of an operation according to an eighth embodiment of the present invention.

FIG. 9 is an explanatory diagram of an operation of a white LED according to the eighth embodiment of the present invention.

FIG. 10 is an explanatory diagram of an operation of a bulb-colored LED according to the eighth embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a structure of a first embodiment of the present invention. As shown in FIG. 1, an illumination device includes a light emitting device 1 such as for example an LED 1, an LED mounting substrate 2 on which the LED is mounted, a case 3 for storing them, and a translucent filling material 4 such as resin 4 (e.g., silicon) for filling the inside of the case 3. The translucent filling material 4 may in fact be entirely transparent in alternative embodiments.

The LED 1 comprising the light emitting device may be provided with a blue LED chip 5 which emits light with a wavelength of approximately 380 to 480 nm, the blue LED chip sealed with a resin 6 (e.g., silicon) containing a phosphor. One sealing resin 6 may encompass a plurality of LED chips 5.

The substrate 2 on which the LED 1 is mounted comprises a base material 7, and a coating (ink) 8 applied on the base material 7. The LED 1 and the substrate 2 are embedded and hermetically sealed in the resin 4. The case 3 is transparent, so that, upon lighting the LED 1, the light therefrom is emitted through the translucent resin 4 and the case 3.

Conventionally, a white coating (ink) has been generally used as the coating (ink) 8 to apply on the base material 7, in consideration of a reflection efficiency for reflecting light reflected by the case 3 and an air layer at the surface of the substrate 2 to emit the light to the outside of the case 3; whereas a yellow coating (ink) is applied in the present embodiment.

Thus, the substrate surface reflects only light within a high luminosity region (yellow light) and absorbs the blue light among the light reflected by the case 3 and the air layer. This can reduce the shift of the color temperature to a higher color temperature, without decreasing an optical output.

In alternative embodiments, the same effect as those described above can be achieved by applying on the substrate surface a substance such as a film 8 which reflects the light within a high luminosity region and absorbs the blue light, instead of coating the base material 7 with the ink 8. Such effect also can be achieved by employing a translucent material other than a resin as the resin 4 for filling the case 3.

In another embodiment as shown in FIG. 2, references 2 a, 2 b and 2 c are LED mounting substrates of the illumination devices different from one another. When the LEDs 1 of a plurality of illumination devices have different color temperatures respectively (i.e., A, B and C depicted in the figure have the different color temperatures), as shown in FIG. 2, the adjustment of a coloration of the coatings (ink) to be applied on the substrate surfaces of the mounting substrates 2 a, 2 b and 2 c of the LEDs 1 can suppress the variation among the color temperatures of the illumination devices. Specifically, a substrate surface having the LED with a low color temperature is colored not to absorb the blue light (for example, white), and a substrate surface having the LED with a high color temperature is colored to absorb the blue light (for example, yellow). Thereby, the variation of the color temperatures can be suppressed among a plurality of illumination devices.

In another embodiment as shown in FIG. 3, references 8 a, 8 b and 8 c are coatings (ink) having different colors respectively, which are applied on the surface of the LED mounting substrate 2 of the illumination device. When the LEDs 1 of a single illumination device have different color temperatures respectively (i.e., A, B and C depicted in the figure have different color temperatures), as shown in FIG. 3, the adjustment of a coloration of the coatings (ink) 8 a, 8 b and 8 c to be applied on the substrate surface of the mounting substrate 2 of the LEDs 1 can suppress the variation of the color temperatures inside of the illumination device. Specifically, the portion of the substrate upon which the LED with a low color temperature is mounted and the periphery thereof are colored not to absorb blue light (for example, white), and the portion of the substrate upon which the LED with a high color temperature is mounted and the periphery thereof are colored to absorb the blue light (for example, yellow). Thereby, the variation of the color temperatures can be suppressed inside of the illumination device.

In an embodiment as shown in FIG. 4, the translucent filling material 4 of the LED assembly comprises a material 9 (e.g., a pigment) that absorbs blue light and that is added in the resin 4. This allows the blue light to be absorbed by the material 9 contained in the resin 4, thereby enabling the reduction of the shift of the color temperature to a higher color temperature. Furthermore, adjustment of a compounding ratio of the material 9 that absorbs the blue light enables the color temperature to be adjusted.

In an embodiment as shown in FIG. 5, the translucent filling material 4 of the LED assembly further comprises a phosphor 10 that converts blue light (light with wavelength of approximately 380 to 480 nm) to light with a wavelength region of approximately 480 to 780 nm. This structure allows the blue light to be converted to the light with the wavelength region of approximately 480 to 780 nm by exciting the phosphor 10 contained in the resin 4. This can reduce the shift of the color temperature to a higher color temperature. In addition, converting the blue light to the light with the wavelength of approximately 480 to 780 nm can increase an optical output in comparison to some alternative embodiments.

The translucent filling material 4 may in certain embodiments comprise both of the phosphor 10 and the pigment 9 in conjunction with each other. An adjustment of the mixing ratio between the phosphor 10 and the pigment 9 within the translucent filling material 4 or resin 4 further enables the color temperature to be adjusted.

In an embodiment of the LED assembly as shown in FIG. 6, the substrate 2 on which a plurality of LEDs 1 a, 1 b and 1 c are mounted includes a base material 7 and yellow coatings (ink) 8 a, 8 b and 8 c applied on the base material 7, and is disposed at an opening of the transparent case 3. The LEDs 1 a, 1 b and 1 c as the light emitting devices are provided with blue LED chips that emit the light with wavelength of approximately 380 to 480 nm, and the blue LED chips are sealed with a resin (for example, silicon) containing a phosphor. In this case, the LEDs 1 a, 1 b and 1 c emit the light varied from one another, and the relationship thereof shall be (a color temperature of the light emitted from the LED 1 a)>(a color temperature of the light emitted from the LED 1 b)>(a color temperature of the light emitted from the LED 1 c).

The inner space of the case 3 is filled with the translucent filling resins (for example, silicon) 4 a, 4 b and 4 c within the respective portions where a plurality of LEDs 1 a, 1 b and 1 c are mounted. The presetting is now made so as to be (a refractive index of the resin 4 a)>(a refractive index of the resin 4 b)>(a refractive index of the resin 4 c).

When the filling is performed onto the LEDs 1 a, 1 b and 1 c with the translucent filling resins 4 a, 4 b and 4 c, the emission colors thereof shift to blue. The shift to blue, however, can be reduced by means of the yellow coatings (ink) 8 a, 8 b and 8 c.

The presetting is now made so as to be (a color temperature of the yellow coating 8 a)<(a color temperature of the yellow coating 8 b)<(a color temperature of the yellow coating 8 c). The higher the color temperatures of the yellow coatings (ink) 8 a, 8 b and 8 c become, the more the substrate 2 absorbs the blue light, thereby reducing the shift to blue. Also, the lower the refractive indices of the translucent filling resins 4 a, 4 b and 4 c become (the nearer the refractive index of the air become), the more the shift to blue is reduced.

Therefore, as shown in the present embodiment, even if the LEDs 1 a, 1 b and 1 c emit light having varying color temperatures from one another, the variation of the color temperatures in the illumination device can be suppressed by adjusting the color temperatures of the yellow coatings (ink) 8 a, 8 b and 8 c applied on the base material 7, as well as the refractive indices of the translucent filling resins 4 a, 4 b and 4 c.

As described above, adjustment of the coloration of the coatings applied on the LED mounting substrate and the refractive indices of the filling resins can suppress the variation of the color temperatures in the illumination device with greater reliability and less cost than alternative methods.

FIG. 7 shows a structure of another embodiment of the LED assembly. The substrate 2 on which a plurality of LEDs 1 a, 1 b and 1 c are mounted includes the base material 7 and the coatings (ink) 8 a, 8 b and 8 c applied on the base material 7, and is disposed at an opening of the transparent case 3. The LEDs 1 a, 1 b and 1 c as the light emitting devices are provided with blue LED chips that emit the light with wavelength of approximately 380 to 480 nm, and the blue LED chips are sealed with a resin (for example, silicon) containing a phosphor. In this case, the LEDs 1 a, 1 b and 1 c emit the light varied from one another, and the relationship thereof shall be (a color temperature of the light emitted from the LED 1 a)=(a color temperature of the light emitted from the LED 1 c)>>(a color temperature of the light emitted from the LED 1 b); the LED 1 a and LED 1 c at both ends of the substrate have desired color temperatures, and the LED 1 b in the middle of the substrate has an extremely low color temperature.

In this case, the coatings (ink) 8 a and 8 c on the periphery of the LEDs 1 a and 1 c at both ends of the substrate are the ones having lower reflectance factors to the blue light, such as yellow. In contrast, the coating (ink) 8 b on the periphery of the LED 1 b in the middle of the substrate is the one having a higher reflectance factor to the blue light, such as white or blue. This structure also includes a coating material 4 b (such as silicon) being applied on the substrate surface (the coating 8 b) on the periphery of the LED 1 b in the middle of the substrate.

Here, when the filling is performed onto the LED 1 b with a translucent filling material 4 b or translucent coating material 4 b such as a translucent resin 4 b, the emission color thereof shifts to blue. Furthermore, since the coating (ink) 8 b with a higher reflectance factor to the blue light increases the reflection of the blue light, the light coming from the coating material 4 b can be shifted to blue. This enables the color temperature thereof to shift to the higher temperature, thereby making it possible to be brought closer to the color temperatures of the LEDs 1 a and 1 c on both ends of the substrate.

Changing the coloration of the coatings on the mounting substrate for the LEDs and coating a part of LEDs with the filling resin can suppress the variation of the color temperatures in the illumination device, even if employing the LEDs with the color temperatures different from one another in the illumination device that requires no filling resin.

Still referring to FIG. 7, the present embodiment permits selection of a color temperature of the LED 1 that is lower than that required for use in the illumination device as shown in the embodiment of FIG. 1. In other words, in consideration of the shift of the color temperature after the filling with the resin 4 in order to be waterproof, the color temperature is previously shifted. Specifically, the adjustment is performed for the compounding ratio of the phosphor that is a constituent of the LED 1, and the color temperature is set to be lower.

FIG. 8 shows an operation of another embodiment of the LED assembly. In the figure, (a) is a spectrum required as the illumination device, (b) is a spectrum of the light emitting device (the LED 1), and (c) is a spectrum after the light emitting device (the LED 1) is filled with the resin 4 to be waterproof.

FIG. 8( a) is an explanatory diagram of the operation of a comparative example, in which the spectrum required as the illumination device and the spectrum of the light emitting device (the LED 1) correspond to each other. Thus, the filling of the light emitting device (the LED 1) with the resin 4 to be waterproof makes the color temperature shift due to the filling, thereby rendering the color temperature different from the one required as the illumination device.

FIG. 8( b) is an explanatory diagram of the operation of the present embodiment, in which spectrum required as the illumination device and spectrum after the light emitting device (the LED 1) is filled with the resin 4 to be waterproof correspond to each other. Although the spectrum required as the illumination device differs from the spectrum of the light emitting device (the LED 1), the filling the light emitting device (the LED 1) with the resin 4 to be waterproof makes the color temperature shift due to the filling, thereby achieving the color temperature required as the illumination device.

Table 1 shows the result of the measurement of the optical characteristics before and after the filling, and Table 2 shows the amount of change before and after the filling of the silicon. FIG. 9 shows a change of the color temperature before and after the filling in the case of white LEDs shown in Tables 1 and 2, and FIG. 10 shows a change of the color temperature before and after the filling in the case of a bulb color.

TABLE 1
Color
Entire output temperature
flux (lm) Color level x Color level y (K)
Before After Before After Before After Before
Samples filling filling filling filling filling filling filling After filling
<White>
White 1 170.3 153.1 0.3553 0.3239 0.3711 0.3253 4714 5921
White 2 170.9 153.5 0.3534 0.3217 0.3675 0.3207 4759 6055
White 3 174.9 160.2 0.3555 0.3254 0.3707 0.3269 4707 5838
<Bulb color>
Bulb 106.9 112.9 0.4602 0.4346 0.4039 0.3930 2641 2946
color 1
Bulb 106.4 111.3 0.4656 0.4420 0.4092 0.4009 2609 2888
color 2
Bulb 106.4 111.1 0.4653 0.4413 0.4085 0.4000 2608 2893
color 3
Bulb 51.2 53.8 0.4706 0.4497 0.4218 0.4162 2639 2890
color 4
Bulb 52.5 55.1 0.4568 0.4328 0.4083 0.3979 2724 3019
color 5

TABLE 2
Rate of Amount of
change of Color level × Color level y change of
entire output Amount of Amount of color
Samples flux (%) change change temperature
<White>
White 1 −10.1 −0.0314 −0.0458 1207
White 2 −10.2 −0.0317 −0.0468 1296
White 3 −8.4 −0.0301 −0.0438 1131
Average −9.6 −0.0311 −0.0455 1211
<Bulb color>
Bulb color 1 5.6 −0.0256 −0.0109 305
Bulb color 2 4.6 −0.0236 −0.0083 279
Bulb color 3 4.4 −0.0240 −0.0085 285
Bulb color 4 5.2 −0.0209 −0.0056 251
Bulb color 5 5.0 −0.0240 −0.0104 295
Average 5.0 −0.0236 −0.0087 283

In the case of the white LED, when the color temperature of 5000K is required for the illumination device and the color temperature of an output flux of the LED 1 is 5000K, employing a waterproof structure as shown in FIG. 1 results in the shift of the color temperature to 6200K. Then, the color temperature of the LED 1 is previously selected at the lower color temperature of the order of, for example, 4000K. The filling of the resin to be waterproof makes the color temperature shift to a higher temperature. Nonetheless it is possible to provide the illumination device with the color temperature of 5000K (FIG. 9).

In the case of the bulb-colored LED, when the color temperature of 2800K is required for the illumination device and the color temperature of an output flux of the LED 1 is 2800K, employing the waterproof structure as shown in FIG. 1 results in the shift of the color temperature to 3100K. Then, the color temperature of the LED 1 is previously selected at a lower color temperature of the order of, for example, 2500K. The filling of the resin to be waterproof makes the color temperature shift to higher temperature. Nonetheless it is possible to provide the illumination device with the color temperature of 2800K (FIG. 10).

By use of embodiments described above, the color temperature can be corrected as desired and necessary for the illumination device.

Thus, although there have been described particular embodiments of the present invention of a new and useful LED Assembly with Color Correcting Substrate it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US8008850 *Oct 28, 2009Aug 30, 2011National Taiwan University Of Science & TechnologyColor temperature tunable white light emitting device
Classifications
U.S. Classification257/88, 257/98, 257/E33.061, 257/E27.12, 257/E33.056
International ClassificationH01L27/15, H01L33/00, H01L33/60, H01L33/52, H01L33/50
Cooperative ClassificationH01L33/52, H01L33/50, H01L33/60, H01L25/0753
European ClassificationH01L33/60
Legal Events
DateCodeEventDescription
Feb 13, 2012ASAssignment
Effective date: 20120101
Free format text: MERGER;ASSIGNOR:PANASONIC ELECTRIC WORKS CO.,LTD.,;REEL/FRAME:027697/0525
Owner name: PANASONIC CORPORATION, JAPAN