JP2007080534A - Light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device with color rendering properties of emission light further improved than that with a conventional structure. <P>SOLUTION: The light source device 1 has main light sources 3 emitting white light, and an auxiliary light source 4 made of an incandescent lamp at its body 2. The main light source 3 has a light-emitting diode emitting blue-color light, and a light-color conversion member containing phosphor excited by absorbing part of light from the light-emitting diode and emitting yellow-color light, and emits white light by mixing the blue-color light and the yellow-color light. The auxiliary light source 4 emits light with light flux smaller than that of the main light source 3 so as to mix it with light from the main light source 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a light source that emits white light having a light emitting diode that emits blue light and a light color conversion member that includes a phosphor that is excited by absorbing part of the light from the light emitting diode and emits yellow light. It relates to the device.

  2. Description of the Related Art Conventionally, light emitting diodes that emit blue light are known, and in recent years, light source devices that can extract white light using this type of (blue) light emitting diode have been provided.

  As this type of light source device, there is one having a configuration in which a light emitting diode (chip) is covered with a light color conversion member that converts a light color of a part of light from the light emitting diode. The light color conversion member is obtained by dispersing a phosphor that is excited by absorbing light from a light emitting diode and emits yellow light in a translucent resin. That is, by converting a part of blue light from the light emitting diode into yellow light with a phosphor, white light which is a mixed color light of blue light and yellow light can be obtained. White light obtained using such a light source device has emission peak wavelengths in a blue wavelength range and a yellow wavelength range.

On the other hand, with the aim of improving the color rendering properties (average color rendering index Ra) of emitted light when the light source device is used for illumination, a light emitting diode that emits red light is added to the light source device described above, and blue light, yellow light, It is conceivable that red light is further mixed with white light obtained by mixing the red light to add light in the red wavelength range to the emitted light (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2004-103443 (page 5-6)

  However, in order to obtain emitted light with high color rendering properties, it is necessary to distribute the emission spectrum over the entire visible light region, whereas the emission spectrum of the light emitting diode is localized in the vicinity of a specific wavelength. Even if the red light emitted from the light emitting diode is mixed with white light as described in Patent Document 1, the emission spectrum is localized in each of the blue, yellow, and red wavelength regions. However, the color rendering properties of the light source device are not sufficiently improved.

  The present invention has been made in view of the above-described reasons, and an object of the present invention is to provide a light source device that can further improve the color rendering properties of emitted light as compared with the conventional configuration.

  The invention of claim 1 includes a light emitting diode that emits blue light and a light color conversion member that includes a phosphor that emits yellow light when excited by absorbing part of the light from the light emitting diode, and emits white light. The apparatus includes a main light source and an auxiliary light source that is composed of an incandescent bulb and emits light having a smaller luminous flux than the main light source so as to be mixed with the light from the main light source.

  According to this configuration, the light emitted from the auxiliary light source is mixed with the white light that is the mixed light of the blue light and the yellow light emitted from the main light source. Here, the auxiliary light source is an incandescent light bulb, and the incandescent light bulb emits light having a light emission spectrum distributed over the entire wavelength range of the visible light region. Therefore, the color mixture of the light from the main light source and the light from the auxiliary light source In light, the emission spectrum is distributed over the entire visible light region, and as a result, the color rendering property of the emitted light of the light source device is further improved as compared with the conventional configuration.

  According to a second aspect of the present invention, in the first aspect of the present invention, the container includes a translucent substrate having translucency, and the main light source faces one surface of the translucent substrate in a direction in which light is emitted forward. The auxiliary light source is fixed on the rear side of the translucent substrate.

  According to this configuration, since the main light source and the auxiliary light source can be arranged in the front-rear direction, the light source device can be reduced in size in a plane along the one surface of the translucent substrate.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a plurality of the main light sources are provided and are arranged so as to surround the auxiliary light source.

  According to this configuration, light emitted from the main light source and the auxiliary light source can be easily mixed with each other.

  According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the auxiliary light source emits red light.

  According to this configuration, since the reddish white light can be obtained as the color mixture light of the light emitted from each of the main light source and the auxiliary light source, the light source device according to claim 4 is used as the light source. It is possible to realize a lighting apparatus suitable for lighting such as food.

  The present invention has an advantage that the emission spectrum is distributed over the entire visible light region, and as a result, the color rendering property of the emitted light of the light source device is further improved as compared with the conventional configuration.

(Embodiment 1)
In the light source device 1 of the present embodiment, as shown in FIG. 1, a plurality of main light sources 3 that emit white light are disposed for a single body 2, and an auxiliary light source 4 formed of an incandescent bulb. Is provided.

  Each main light source 3 includes a light emitting diode (not shown) that emits blue light and a light color conversion member (not shown) that covers the light emitting diode. The light color conversion member is a material in which a fluorescent material excited by absorbing blue light and emitting yellow light is dispersed in a light transmitting resin (for example, silicone resin or epoxy resin). Of the light (blue light) incident on this light color conversion member, part of the light is converted to yellow light by the phosphor and output, and the other light is light color converted without being absorbed by the phosphor. Since the light is transmitted through the member and output as blue light, the light emitted from the main light source 3 is white light that is a mixed color of blue light and yellow light that are complementary to each other.

  Although not shown in detail in FIG. 1, each main light source 3 has a light emitting diode (chip) mounted on the bottom surface of a recess provided in one surface of a package (not shown), and the opening of the recess is formed in a plate shape. Each of the light color conversion members is configured to be closed. As a result, white light is emitted from the opening of the recess through the light color conversion member. However, the configuration of the main light source 3 is not limited to this. For example, the main light source 3 may be configured by mounting a light emitting diode (chip) on a lead frame and molding the lead frame with a light color conversion member. The light emitting diode used here is a chip in which a light emitting portion made of a gallium nitride compound semiconductor material is formed on one surface side of a sapphire substrate, and an emission peak wavelength of an emission spectrum at room temperature is about 460 nm.

In the present embodiment, two types of phosphors that emit light having different emission peak wavelengths are used as the phosphors of the light color conversion member. As the two types of phosphors, a known phosphor that is excited by absorbing blue light from a light emitting diode and emits light over a wavelength range of 500 to 700 nm may be used (that is, the emission peak wavelength is yellow). For example, an alkaline earth metal orthosilicate phosphor may be used. Here, a case where a phosphor having a composition of (Sr, Ca, Ba) ₂ SiO ₄ : Eu ²⁺ and having a light emission peak wavelength at room temperature of 520 nm and a phosphor having a wavelength of 590 nm is illustrated. In each of the phosphors described above, assuming that the composition of Sr is a, the composition of Ca is b, and the composition of Ba is c, a + b + c = 2 (that is, a = 2−b−c), and the composition ratio is By adjusting, it is possible to shift only the emission peak wavelength with almost no change in the half width of the emission spectrum, and in the phosphor having the emission peak wavelength of 520 nm, the composition of Ba is compared with the phosphor having the emission peak wavelength of 590 nm. The composition ratio (= c / b) between c and the composition b of Ca is high.

In the light color conversion member, the concentration ratio (wt% ratio) between the phosphor having an emission peak wavelength of 520 nm and the phosphor having an emission peak wavelength of 590 nm is set to 35:65. Here, the respective phosphors, the average particle size d ₅₀ is using a particulate phosphor 5 [mu] m.

  With the configuration described above, the main light source 3 emits light having an emission spectrum indicated by “A” in FIG. That is, when the main light source 3 emits light alone, as described in the conventional configuration, light having emission peak wavelengths in the blue wavelength range and the yellow wavelength range is obtained.

  On the other hand, in the light source device 1 of the present embodiment, the auxiliary light source 4 is provided in addition to the main light source 3 as described above, and the auxiliary light source 4 is composed of an incandescent bulb. As shown in FIG. 2, light having an emission spectrum distributed over the entire wavelength region of the visible light region is emitted. Here, the main light beam extracted from the light source device 1 is emitted from the main light source 3, and light having a smaller light beam than the plurality of main light sources 3 is extracted from the auxiliary light source 4. In the present embodiment, a small-sized halogen bulb (so-called bean bulb) is used as the auxiliary light source 4 among known halogen bulbs, but other incandescent bulbs may be used. The light from the auxiliary light source 4 is mixed with the light from the main light source 3 by means described later.

  Moreover, the container 2 is provided with the transparent resin-made translucent board | substrate 5 which has translucency, as shown in FIG. 1, All the several main light sources 3 are the front surfaces (FIG. 1) of the translucent board | substrate 5. The auxiliary light source 4 is arranged behind the translucent substrate 5 (upper side in FIG. 1). However, the main light source 3 may be fixed to the rear surface of the translucent substrate 5. Here, the main light source 3 is arranged in a direction in which light is emitted forward (downward in FIG. 1) (that is, the concave portion of the package is directed forward). Although only the translucent substrate 5 is illustrated in FIG. 1, the lamp 2 for holding the auxiliary light source 4 and the auxiliary light source 4 between the translucent substrate 5 are also provided in the container 2. A cover that forms a storage space, a reflector that is formed on the inner peripheral surface of the cover, and that distributes light from the auxiliary light source 4 forward are provided.

  According to the above-described configuration, the light source device 1 transmits the light of the main light source 3 having the emission spectrum shown by “A” in FIG. 2 (indicated by the solid line arrow in FIG. 1) and the “B” in FIG. Both of the light of the auxiliary light source 4 having the emission spectrum shown (indicated by broken arrows in FIG. 1) can be taken out in front of the body 2. At this time, by mixing the light from the auxiliary light source 4 with the light from the main light source 3, the emission spectrum is distributed over the entire visible light region, and light having a broadband emission spectrum is obtained. Can do. In this way, by mixing the light from the main light source 3 and the light from the auxiliary light source 4, the color rendering property (average color rendering index Ra) of the light source device 1 is higher than when the main light source 3 emits light alone. Will improve.

  As a means for mixing the light from the main light source 3 and the light from the auxiliary light source 4, a diffuse transmission plate (not shown) is provided in front of the main light source 3 in the container 2, and the main light source 3 and the auxiliary light source 4. A configuration may be adopted in which light emitted from each is diffused by a diffusion transmission plate and then extracted, and is not limited to this configuration. For example, when the light source device 1 is used as a light source of a lighting fixture, the lighting fixture is provided. The light from the main light source 3 and the light from the auxiliary light source 4 are mixed using a diffused transmission plate (such as a shade), or the region irradiated with the light from the main light source 3 on the irradiation surface and the auxiliary light source The two light beams may be mixed on the irradiation surface by overlapping the region irradiated with the light from 4.

  Further, as described above, the light flux relationship between the light from the plurality of main light sources 3 and the light from the auxiliary light source 4 is set so that the light from the main light source 3 is larger. The main light source 3 is also configured to have a larger relationship between the power consumption of the plurality of main light sources 3 and the power consumption of the auxiliary light source 4. In the present embodiment, an example in which a plurality of main light sources 3 are provided has been described. However, only one main light source 3 may be provided. Even when the number of the main light sources 3 is one, the relationship between the light beams of the light of the main light source 3 and the light of the auxiliary light source 4 is set so that the main light source 3 is larger. A plurality of auxiliary light sources 4 may be provided.

(Embodiment 2)
The light source device 1 of the present embodiment is different from the light source device 1 shown in the first embodiment in the arrangement of the main light source 3 and the auxiliary light source 4.

  That is, in the light source device 1, as shown in FIG. 3, the body 2 is formed in a circular disk shape on the front surface (lower surface in FIG. 3), and the auxiliary light source 4 is disposed in the center of the front surface of the body 2. A plurality of main light sources 3 are arranged so as to surround the auxiliary light source 4 on the front surface of the container 2. In FIG. 3, eight main light sources 3 are arranged at equal intervals along the peripheral edge of the front surface of the vessel 2. Here, the main light source 3 and the auxiliary light source 4 are accommodated in the container 2, and holes for extracting light from the main light source 3 and the auxiliary light source 4 are formed on the front surface of the container 2.

  According to this configuration, both the light from the main light source 3 and the light from the auxiliary light source 4 can be extracted from the light source device 1 to the front of the container body 2. In addition, since the auxiliary light source 4 is disposed at a position surrounded by the main light source 3, there is an advantage that the light emitted from each of the main light source 3 and the auxiliary light source 4 can be easily mixed with each other.

  In the present embodiment, an incandescent bulb (bean bulb) in which a glass bulb is colored red is used as the auxiliary light source 4. Thereby, red light is emitted from the auxiliary light source 4, and the red special color rendering evaluation of the light source device 1 is performed as compared with the case where the incandescent bulb having a colorless and transparent glass bulb is used as the auxiliary light source 4. The number (R9) will be improved. On the other hand, for example, a lighting device that illuminates foodstuffs, such as a lighting device used in a restaurant or the like, has a high red color rendering index (R9) as well as an average color rendering index (Ra). It is known. Therefore, by using the light source device 1 with improved red special color rendering index (R9) as the light source as in the present embodiment, it is possible to realize a lighting fixture suitable for lighting foods and the like.

  In addition, even if it does not provide a hole in the front surface of the container 2, the light of the main light source 3 and the auxiliary light source 4 can be taken out by using the translucent substrate 5 as described in the first embodiment on the front wall of the container 2. You may do it. In this case, the main light source 3 may be fixed to the outside of the container 2. Other configurations and functions are the same as those of the first embodiment.

It is the schematic which shows the structure of Embodiment 1 of this invention. It is explanatory drawing of the emission spectrum in the same as the above. It is a perspective view which shows the structure of Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source device 2 Body 3 Main light source 4 Auxiliary light source 5 Translucent substrate

Claims (4)

  A main light source that emits white light having a light-emitting diode that emits blue light and a light-color conversion member that includes a phosphor that emits yellow light when excited by absorbing part of the light from the light-emitting diode; A light source device comprising: an auxiliary light source that emits light having a light flux smaller than that of a main light source so as to be mixed with light from the main light source.   The container includes a translucent substrate having translucency, the main light source is fixed on one surface of the translucent substrate in a direction to emit light forward, and the auxiliary light source is the translucent substrate. The light source device according to claim 1, wherein the light source device is disposed behind.   3. The light source device according to claim 1, wherein a plurality of the main light sources are provided and arranged so as to surround the auxiliary light source.   4. The light source device according to claim 1, wherein the auxiliary light source emits red light. 5.

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