WO2012035799A1

WO2012035799A1 - Lighting device

Info

Publication number: WO2012035799A1
Application number: PCT/JP2011/054877
Authority: WO
Inventors: 高橋　健; 修小野; 松田　秀三; 信雄川村; 修介森田; 横田　昌広; 西村　孝司
Original assignee: 株式会社東芝
Priority date: 2010-09-16
Filing date: 2011-03-03
Publication date: 2012-03-22
Also published as: JP2012064476A; JP5532329B2

Abstract

A lighting device is provided with: a radiation surface; at least one light source (16) which is arranged so as to face the radiation surface; and a phosphor layer (24) which is arranged in-between the radiation surface and the light source so as to be estranged from the light source, and which has a pattern of phosphor, which are excited by the light from the light source.

Description

Lighting device

Embodiments of the present invention relate to a lighting device including a light source and a phosphor that converts the wavelength of light from the light source.

An illumination device that obtains desired white light by combining an LED light source and a phosphor has been proposed. Disposing the LED light source, which is a heat generation source, and the phosphor apart from each other is effective in improving luminous efficiency in terms of avoiding phosphor degradation such as temperature quenching. On the other hand, the phosphor has a high refractive index and acts as scattering particles. For this reason, when the phosphor is provided in the vicinity of the LED light source, the phosphor scatters the light emitted from the LED and returns it to the LED, resulting in an efficiency loss. From these, the technique which arrange | positions LED light source and fluorescent substance spaced conventionally is examined.

A planar illumination device has been proposed in which light emitted from a short wavelength LED is partly converted to a long wavelength by a phosphor arranged at a location distant from the LED, and white light is emitted.

Also, two layers of phosphor layers that convert to a long wavelength are disposed at a location away from the LED, and a longer wavelength phosphor layer is disposed on the short wavelength light source side, thereby eliminating unnecessary conversion between phosphors. There has been proposed a planar lighting device that prevents the above. Furthermore, a light bulb illumination device has been proposed in which a long wavelength phosphor is applied to the inner surface of a globe of a light bulb surrounding a short wavelength light source to emit white light.

Japanese Patent No. 3114805 Japanese Patent No. 317539 Japanese Patent No. 41007057 Japanese Patent Laid-Open No. 2005-5546

However, with the conventional technology, it is difficult to adjust the color tone and the luminance distribution even though the phosphor can be arranged away from the LED light source. In addition, the phosphor layer undergoes color conversion due to light from the outside, and a specific object color is attached to the exit surface of the illumination device when it is not lit.

An object of the present invention is to provide an illuminating device that can control and adjust the color tone and luminance and that has improved light extraction efficiency.

According to the embodiment, the lighting device is disposed between the radiation surface, at least one light source disposed to face the radiation surface, and spaced from the light source between the radiation surface and the light source, A phosphor layer obtained by patterning a phosphor excited by light from a light source.

FIG. 1 is a cross-sectional view illustrating a lighting device according to a first embodiment. FIG. 2 is a plan view showing an optical member of the illumination device. FIG. 3 is a cross-sectional view illustrating an illumination device according to a second embodiment. FIG. 4 is a cross-sectional view illustrating a lighting device according to a third embodiment. FIG. 5 is a cross-sectional view illustrating a lighting device according to a fourth embodiment. FIG. 6 is a cross-sectional view showing a lighting device according to a fifth embodiment. FIG. 7 is a cross-sectional view showing a lighting device according to a sixth embodiment. FIG. 8: is sectional drawing which shows the illuminating device which concerns on 7th Embodiment.

Hereinafter, various embodiments will be described in detail with reference to the drawings.
(First embodiment)
1 and 2 show an illumination device according to the first embodiment. As illustrated in FIG. 1, the lighting device 10 includes, for example, a rectangular circuit board 12 disposed on the back surface side, at least one light source provided on the circuit board 12, for example, an LED chip 16, and the circuit board 7. A lower reflector 14 formed on the upper surface of the LED, a transparent protective layer 18 that does not include a phosphor covering the LED chip 16, and a rectangular shape disposed on the LED chip 16 in parallel with the lower reflector 14 at an interval. Disposed between the diffusion plate 26, a rectangular frame-shaped side wall (not shown) disposed between the circuit board 12 and the diffusion plate 26, and the LED chip 16 and the diffusion plate 26, with a gap between the LED chip 16 and the gap. And an opposing sheet-like optical member 20. The outer surface of the diffusing plate 26 constitutes an emission surface of the lighting device 10.

As shown in FIGS. 1 and 2, the optical member 20 includes, for example, a rectangular transparent sheet 22, a reflective layer 28 formed on the surface of the transparent sheet 22 on the diffusion plate 13 side, and an LED of the transparent sheet 22. The phosphor layer 24 is formed on the surface on the chip 16 side, that is, the phosphor layer 24 is patterned on the light incident side with respect to the reflective layer 28.

The phosphor layer 24 is formed in a dot or stripe pattern on the transparent sheet 22, and is disposed separately for each emission color, such as a green light emitting layer 24a and a red light emitting layer 24b. The green light emitting layer 24a and the red light emitting layer 24b are formed in, for example, a rectangular shape and are formed in various different dimensions. The green light emitting layer 24a and the red light emitting layer 24b are arranged in a predetermined pattern with a gap therebetween.

The reflective layer 28 is formed on the upper surface side of the transparent sheet 22 in a pattern corresponding to the pattern opening of the phosphor layer 24 and is disposed so as to fill the pattern opening of the phosphor layer 24. The reflective layer 28 is provided with an opening 28 a in an area where the phosphor layer 24 is absent and only the transparent sheet 22 is provided.

For example, when white illumination is obtained by a combination of a blue light emitting LED chip and a phosphor layer, unevenness occurs in the distribution of light entering the transparent sheet 22 from the LED chip 16, and the light distribution of the LED chip is a Lambertian distribution. Assuming that there is a large amount of light in the upper part of the LED chip, the incident light quantity decreases as the distance from the upper part of the LED chip increases. In addition, it is difficult to provide a distribution of the thickness and phosphor concentration of the phosphor layer 24 formed on the transparent sheet 22 depending on the position. In order to improve these problems, the phosphor layer 24 is patterned by printing in the illumination device of this embodiment. The phosphor layer 24 is formed in a pattern in which the area occupied by the phosphor layer 24 is small immediately above the LED chip 16 and the area occupied by the phosphor layer 24 increases as the distance from the LED chip 16 increases. The reflective layer 28 is printed and formed so as to fill the empty portion of the layer pattern, that is, the pattern opening.

According to the illuminating device 10 configured as described above, the short wavelength light emitted from the LED chip 16 is partially converted into a long wavelength by the phosphor layer 24 disposed at a position away from the LED chip, White light can be emitted from the exit surface. By controlling the aperture distribution of the phosphor layer 24 and the reflective layer 28 with the pattern as described above, the high luminance directly above the LED chip 16 can be relaxed and the luminance can be uniform over the entire emission surface. In addition, since the reflective layer 28 reflects light rays entering the illumination device 10 from the outside (solid line arrows in FIG. 1), it is possible to mitigate the occurrence of color caused by external light conversion by the phosphor layer 24.

The light passing through the phosphor layer 24 is mainly in the vertical direction immediately above the LED chip 16, while the light passing through the phosphor layer 24 is mainly in the oblique direction in the middle portion away from directly above the LED chip. For this reason, a difference occurs in the effective thickness of the phosphor layer 24 through which the LED transmitted light is transmitted, and the emission wavelength distribution has a strong LED light source wavelength component directly above the LED chip and a strong phosphor emission wavelength component in the middle portion. . As a result, the chromaticity unevenness in which the color tone is shifted depending on the location occurs on the emission surface. In order to improve these, in this embodiment, the opening pattern of the reflective layer 28 is adjusted, and the opening 28a is provided in the reflective layer 28 at a location where the phosphor layer 24 does not transmit in the intermediate portion of the optical member 20. . Thereby, the LED light source wavelength component in the intermediate portion can be compensated.
From the above, it is possible to provide a lighting device that can control and adjust the color tone and luminance and that has improved light extraction efficiency.

In the above-described embodiment, the phosphor layer and the reflective layer are formed by using a printing process. However, the present invention is not limited thereto, and may be formed by using another means such as a dispenser, an ink jet, photolithography, and the like. The phosphor layer may be formed of a sheet formed by mixing phosphors with holes or irregularities.

Further, the optical effect by the pattern formation of the phosphor layer and the reflection layer is not limited to uniform luminance, and the luminance distribution and color tone may be changed depending on the location on the surface.

Further, in this embodiment, the reflective layer 28 is provided with an opening through which the transparent sheet 22 is exposed in order to directly emit the light of the LED 16 to the radiation surface, but the light of the LED 16 is similar to the light from the phosphor layer 24. In order to have the light distribution on the radiation surface, a diffuser member having a diffusibility comparable to that of the phosphor layer and having no color conversion function may be formed in the same opening. In this case, the light from the LED 16 and the light from the phosphor layer 24 have the same light distribution, and coloring due to the viewing angle can be prevented.

In the present embodiment, the light source is disposed so as to face the radiation surface. However, the arrangement of the light source and the radiation surface is not particularly limited. For example, the light source may be disposed on the side surface of the radiation surface. In this case, it is desirable to configure the phosphor layer so that the area occupied by the phosphor increases as the distance from the light source increases.

Next, a lighting device according to the second embodiment will be described.
FIG. 3 shows an illumination device according to the second embodiment. According to the second embodiment, the transparent protective layer 18 that protects the LED chip 16 is provided with a prism function, and the light distribution of the light emitted from the LED chip 16 is illuminated with respect to the planar phosphor layer 24. It is configured to be uniform. In the optical member 20, the phosphor layer 24 and the reflective layer 28 are formed on the same surface of the transparent sheet 22, here on the surface facing the LED chip 16. As in the first embodiment, the phosphor layer 24 has a pattern in which the area occupied by the phosphor layer 24 is small immediately above the LED chip 16 and the area occupied by the phosphor layer 24 increases as the distance from the LED chip 16 increases. It is formed with. The reflective layer 28 is patterned on the transparent sheet 22 so as to fill the empty portion of the phosphor layer pattern, that is, the pattern opening.

In the second embodiment, the other configuration of the illumination device 10 is the same as that of the first embodiment described above, and the same reference numerals are given to the same portions, and detailed descriptions thereof are omitted.

The protective layer 18 that protects the LED chip is essentially transparent, and can control the direction of light emitted from the LED as a lens or a prism. According to this embodiment, since the phosphor layer is separated from the protective layer 18, the protective member can be used as a lens or a prism.

According to the second embodiment, the illuminance distribution that the LED chip irradiates the phosphor layer becomes uniform, the occupancy ratio of the phosphor is uniformed in a planar shape, and the reflection layer can be uniformly distributed as well. Thereby, generation | occurrence | production of the brightness nonuniformity resulting from LED arrangement | sequence can be suppressed. In addition, also in 2nd Embodiment, the effect similar to 1st Embodiment can be acquired.

Next, an illumination device according to the third embodiment will be described.
FIG. 4 shows an illumination device according to the third embodiment. According to the third embodiment, the optical member 20 includes a non-patterned sheet-like phosphor layer 24 and a reflective layer 28 that is patterned on the phosphor layer on the diffusion plate 26 side. Yes. Here, the phosphor layer 24 is illustrated as a sheet formed by mixing a resin and a phosphor, but a laminated structure in which the phosphor is applied to the entire surface of the transparent sheet may be used.

In the third embodiment, the other configuration of the illumination device 10 is the same as that of the first embodiment described above, and the same reference numerals are given to the same parts, and detailed description thereof is omitted.

According to the third embodiment, light entering from the outside can be reflected by the reflection layer 5 and color conversion of the phosphor layer 24 by external light can be mitigated. In addition, strong light directly above the LED chip 16 is shielded and relaxed by the reflective layer 5, and the luminance of the emission surface is made uniform. In addition, also in 3rd Embodiment, the effect similar to 2nd Embodiment can be acquired.

Next, a lighting device according to the fourth embodiment will be described.

FIG. 5 shows a lighting device according to the fourth embodiment. In 4th Embodiment, the illuminating device 10 has the structure which deleted the reflection layer 28 in 1st Embodiment mentioned above. Even in a configuration without a reflective layer, the phosphor area that reflects external light (solid arrow) is reduced by patterning the fluorescent layer 24, so that changes in color caused by external light conversion can be mitigated. Other configurations and effects are the same as those of the first embodiment.

Next, an illuminating device according to a fifth embodiment will be described.
FIG. 6 shows a light bulb-type lighting device according to the fifth embodiment. According to the present embodiment, the lighting device includes a flat circuit board 12, a lower reflector 14 formed on the upper surface of the circuit board 12, and one or a plurality of LED chips disposed on the circuit board 12. (Point light source) 16, a transparent protective layer 18 that protects the point light source 16, and a light source 16 and a lower reflector 14 that are disposed on the light extraction side of the LED chip 16, for example, a dome-shaped globe, An envelope 30, an optical member 20 disposed between the LED chip 16 and the envelope 30, a heat dissipating part provided on the lower surface side of the circuit board 12, and a light bulb base 32 are provided. The envelope 6 is made of a transparent or translucent material such as glass, and the outer surface of the envelope 30 constitutes an emission surface of the lighting device.

The optical member 20 includes, for example, a hemispherical transparent sheet 22, a phosphor layer 24 patterned on the inner surface of the transparent sheet on the point light source 16 side, and a reflective layer 28 patterned on the outer surface of the transparent sheet. And have. The reflective layer 28 is patterned on the transparent sheet 22 so as to fill the empty portion of the phosphor layer pattern, that is, the pattern opening. The optical member 20 is disposed on the lower reflector 14 and covers the LED chip 16.

According to the fourth embodiment having the above-described configuration, the light loss from the LED chip is scattered and returned to the LED chip 16 by disposing the highly scattering phosphor layer 24 away from the LED chip 16 in a dome shape. And the light distribution of the lighting device can be expanded to the same extent as that of a conventional incandescent bulb. In addition, by reflecting the light incident from the outside by the reflection layer 28, it is possible to reduce the color tone generated by the conversion of the phosphor layer by the external light. Various light distributions and optical effects can be imparted by changing the shape of the transparent sheet 22.

FIG. 7 shows a light bulb-type lighting device according to the sixth embodiment. In the present embodiment, the phosphor layer 24 is formed of an independent sheet in which a resin and a phosphor are mixed. Separately from this, the reflection layer 28 is formed on the transparent sheet 22 and the both are stacked. Other configurations of the illumination device are the same as those of the fifth embodiment described above. Even in such a configuration, the same function as that of the above-described embodiment can be exhibited.

FIG. 8 shows a light bulb-type lighting device according to the seventh embodiment. According to the present embodiment, the phosphor layer 24 and the reflective layer 28 constituting the optical member are formed directly on the inner surface of the envelope 30 and face the LED chip 16. The phosphor layer 24 is patterned, and the reflective layer 28 is patterned on the inner surface of the envelope 30 so as to fill the empty portion of the phosphor layer pattern, that is, the pattern opening. The other configuration of the illumination device is the same as that of the above-described fourth embodiment, and the same reference numerals are given to the same portions, and detailed description thereof is omitted.

According to the present embodiment, the light distribution of the lighting device can be expanded to the same extent as that of a conventional incandescent bulb, and the number of components and the manufacturing cost can be reduced by omitting the transparent sheet. .

The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
For example, the optical member may be composed of only the phosphor layer, omitting the reflective layer. Even in this case, the luminance distribution and the color tone can be controlled by adjusting the pattern of the phosphor layer.

12 ... Circuit board, 14 ... Bottom reflector, 16 ... LED chip, 18 ... Transparent protective layer,
22 ... transparent sheet, 24 ... phosphor layer, 26 ... diffusion plate, 28 ... reflection layer,
30 ... Globe, 32 ... Light bulb cap,

Claims

A radiation surface;
At least one light source disposed opposite the radiation surface;
An illuminating device comprising: a phosphor layer that is disposed between the radiation surface and the light source and is spaced apart from the light source and patterned with a phosphor that is excited by light from the light source.
The lighting device according to claim 1, further comprising: a reflective layer that reflects external light incident from the radiation surface side on the radiation surface side of the phosphor layer.
The phosphor layer has a pattern opening formed in a pattern separated into a plurality of locations, the reflection layer has a plurality of openings, and these openings are opposed to the phosphor layer. The lighting device according to claim 2.
4. The illumination device according to claim 3, wherein the aperture pattern of the phosphor layer and the reflective layer is controlled by an aperture ratio distribution defined by a relative position with respect to the light source.
5. The method according to claim 2, further comprising a molded sheet having a thickness of 0.1 mm to 1.0 mm provided to face the light source, wherein the phosphor layer and the reflective layer are formed on the molded sheet. The lighting device according to item 1.
A dome-shaped envelope covering the light source and forming the radiation surface;
The lighting device according to any one of claims 2 to 4, wherein the phosphor layer and the reflective layer are formed on an inner surface of the envelope.
5. The illumination device according to claim 1, wherein the light source is an LED, and includes a transparent protective layer that covers the LED, and the protective layer has an interface that functions as a lens or a prism. .