JP2007109673A - Illumination device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illumination device that uses a light source like an LED preventing an irradiated object from color-change, when emitted light is irradiated thereon by emitting a light having a wide wavelength band. <P>SOLUTION: Light having a wide-ranged wavelength band can be emitted from the illumination device, by widening the wavelength band of at least one light source from among three light sources 16a, 16b, 16c having wavelength bands that differ from one other, by using fluorescent materials 22a, 22b, 22c. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illuminating device mainly used for indoor (indoor) illumination, and particularly to an illuminating device using light sources of two or more colors.

  Conventionally, incandescent lamps and fluorescent lamps are mainly used as light sources for indoor lighting devices. Instead of these light sources, light emitting diodes (LEDs), which are fixed light emitting elements using semiconductors, are used for indoor lighting. It is considered to be used as a light source. That is, the LED is expected as a future illumination means because of its features such as small size, high brightness, and long life. At present, the conversion efficiency is not as good as about 1/6 of that of a general fluorescent lamp, so the use in the field of illumination is small. May become the mainstream of lighting. By the way, in order to use an LED as a light source for an indoor lighting device, since the LED is originally a point or linear light source, it must be changed to a planar light source.

  Conventionally, as a planar light source device using an LED as a light source, a surface light source device for a backlight of a liquid crystal display screen of various electric devices or the like is known. A light-guide type surface light source device using a conventional LED as a light source is shown in a perspective view of FIG. 1 and a cross-sectional view of FIG. The surface light source device 100 includes a light guide plate 2 for confining light, a light emitting unit 3, and a reflection plate 4. The light guide plate 2 is formed of a transparent and high refractive index resin such as polycarbonate resin or methacrylic resin, and a diffusion pattern P is formed on the lower surface of the light guide plate 2 by uneven processing or dot printing of diffuse reflection ink. Yes. The light emitting unit 3 is a circuit board 3a on which a so-called point light source 3b such as a plurality of LEDs is mounted, and faces the side surface (light incident surface 7) of the light guide plate 2. The reflection plate 4 is formed of, for example, a white resin sheet having a high reflectance, and both side portions thereof are attached to the lower surface of the light guide plate 2 by a double-sided tape 8.

  As shown in FIG. 2, the light f emitted from the light emitting unit 3 and guided to the inside of the light guide plate 2 from the light incident surface 7 is totally reflected inside the light guide plate 2 to be inside the light guide plate 2. Be trapped. When the light f inside the light guide plate 2 is incident on the diffusion pattern P, it is diffusely reflected, and the light f reflected toward the light emitting surface 6 at an angle smaller than the critical angle of total reflection is externally transmitted from the light emitting surface 6. Is taken out. Further, the light f that has passed through the portion where the diffusion pattern P does not exist on the lower surface of the light guide plate 2 is reflected by the reflecting plate 4 and returns to the inside of the light guide plate 2 again, thereby preventing light quantity loss from the lower surface of the light guide plate 2. Can do.

  As a means for realizing an indoor lighting device using an LED as a light source, a method of enlarging a light guide type surface light source device as shown in FIG. 1 and FIG. A method of spreading light using a diffusing member or the like is conceivable. Whichever means is used, whitening of the light source is inevitable when the LED is used as the light source of the illumination device. As a method for whitening the light source, for example, three types of LEDs that emit light of three primary colors of red (R), green (G), and blue (B) are used, and light emitted from these three LEDs is used. There are a method of mixing and making white light, and a method of emitting a white light by applying a fluorescent material that generates ultraviolet light on the surface of the LED, but considering the light conversion efficiency and the possibility of color adjustment The former whitening by mixing three colors is more effective.

  However, since the illumination device using the three types of LEDs that emit light of the three primary colors of R, G, and B as light sources as described above cannot emit light in a wide wavelength band, When an object is irradiated with light emitted from a light source, there is a problem that the color of the irradiated object changes and appears.

  FIG. 3 is a diagram illustrating a spectrum of a general LED of three primary colors of R, G, and B. As is well known, all colors can be reproduced if there are light sources of the three primary colors R, G, and B. However, this means that when the light emitted from the light source is directly viewed as in a display, all the colors can be equivalently reproduced with R, G, and B. When an object is irradiated and the light reflected by the object is viewed once, it is not always necessary to emit only R, G, and B light.

  FIG. 4 is a diagram illustrating an example of a reflection spectrum of an object that looks yellow under sunlight. When such an object is irradiated with an illumination device having light sources of the three primary colors R, G, and B shown in FIG. 3, there is almost no emitted light corresponding to the yellow wavelength band from the illumination device. There is almost no reflected light from an object that looks yellow, and the color of this object changes and appears. When an LED is used as the light source, this tendency appears particularly strongly because the wavelength band of the emitted light of the LED is narrow. In order to improve this, use a light source having a broader spectrum as shown by the broken line in FIG. 3 instead of a light source that emits only the light of the three primary colors R, G, and B as shown by the solid line in FIG. is required. FIG. 5 is a diagram showing reflected light from the yellow object shown in FIG. When light from a light source having a broad spectrum shown in (2) is irradiated, compared to the case where only light of the three primary colors R, G, and B shown in (1) is irradiated, a yellow object is emitted. It can be seen that there is a lot of reflected light.

  In order to broaden the spectrum, not only LEDs of the three colors R, G, and B, but also light (1) in the middle wavelength band of R and G shown in FIG. An LED that emits light (2) in the band may be used. However, this method is not practical because five types of LEDs are used and the circuit becomes complicated.

  In addition to using the light source having the above five types of LEDs, there is a method using a fluorescent material as a method of expanding the wavelength band of the emitted light. However, even if a fluorescent material is used, it is not possible to freely control the wavelength band. Therefore, as shown in FIG. 7, only an LED that emits light (1) in one wavelength band as an original light source is used. When used, the light (2) spread by the fluorescent material may be strong in only a part of the wavelength band, or may remain in the original wavelength band of the light source, and cannot be said to be sufficient light for illumination. It was. In addition, when shifting the light on the short wavelength side to the long wavelength side, if the shift width is wide, the loss of energy is large and there is a problem in energy efficiency.

  The present invention has been made to solve the above-described problems, and does not complicate a circuit connected to a light source or intensify only light in a part of the wavelength band, and can emit light in a wide wavelength band. An object of the present invention is to provide an illuminating device that can prevent the color of an irradiated object from changing when the object is irradiated with the emitted light so that the object can be emitted. .

  In order to achieve the above object, the invention according to claim 1 broadens the wavelength band of any one of the two or more light sources that emit light having different wavelength bands and the two or more light sources. A fluorescent material; and a color mixing unit that mixes light from at least one of the two or more light sources and light that has passed through the fluorescent material, the fluorescent material comprising the light source and the color mixing unit. In the meantime, it is arranged at a position where only the light that reacts with the fluorescent material passes, and the color mixing means emits light having a wider wavelength band than each of the light sources.

  In this configuration, the fluorescent material can be used to broaden the wavelength band of at least one of the two or more types of light sources having different wavelength bands. By using a light source with a wavelength band of, it is possible to emit light in a wide wavelength band from the lighting device. Thereby, when the emitted light is irradiated to the object, it is possible to prevent the color of the irradiated object from changing and appearing. In addition, since only light in a wavelength band that reacts with the fluorescent material is incident on the fluorescent material, it is possible to prevent a decrease in light intensity due to light that does not react with the fluorescent material passing through the fluorescent material.

  Each of the two or more types of light sources may be a light emitting diode that emits one of red, green, and blue light. Thereby, in the illuminating device using LED which has the characteristics, such as small size, high brightness | luminance, and long lifetime, as said light source, said effect | action can be acquired.

  Two or more kinds of the fluorescent material may be used. Thereby, since the wavelength band of two or more types of light sources having different wavelength bands can be expanded, the wavelength band of light emitted from the illumination device can be easily expanded.

  Further, at least one of the two or more types of fluorescent materials may be one that widens the wavelength band of the light source on the shortest wavelength side. Thereby, since it is possible to emit light in a short wavelength region using a light source having an expanded wavelength band, when irradiating an object having a color corresponding to light in the short wavelength region, It can prevent the color of the irradiated object from changing and appearing.

  According to the illuminating device of claim 1, since the wavelength band of at least one of the two or more types of light sources having different wavelength bands is expanded using the fluorescent material, this wavelength band Using a light source with a wider wavelength range and a light source in another wavelength band, the light emitted from the illumination device in a wide wavelength band changes the color of the irradiated object when the emitted light is irradiated onto the object. Can be prevented. Therefore, the circuit connected to the light source becomes more complicated than when light of a wide wavelength band is emitted using five types of light sources that cover light in all wavelength bands in the visible light region. Disappear. Compared to the case where the wavelength band of one type of light source is widened and an object is irradiated using only the light source with this widened wavelength band, only light in a part of the wavelength band becomes stronger, It is possible to prevent the light in the original wavelength band from remaining. Furthermore, compared with the case where the wavelength band of one kind of light source is extended over a wide range, the width for expanding the wavelength band can be narrowed, so that the energy loss can be reduced. In addition, since the fluorescent material is disposed between the light source and the color mixing means at a position where only light that reacts with the fluorescent material passes, only light in a wavelength band that reacts with the fluorescent material is incident on the fluorescent material. It is possible to prevent a decrease in light intensity due to light that does not react with the fluorescent material passing through the fluorescent material.

  Further, each of the two or more types of light sources is a light emitting diode that emits one of red, green, and blue light, thereby using an LED having features such as small size, high luminance, and long life as a light source. Thus, an effect equivalent to that of the first aspect can be obtained.

  Further, by using two or more types of fluorescent materials, the wavelength bands of two or more light sources having different wavelength bands can be expanded. Thereby, since the light of a wide range of wavelength bands can be emitted from the illumination device using two or more types of light sources that have expanded these wavelength bands, the effect of claim 1 can be obtained accurately. it can.

  In addition, by using at least one of the two or more types of fluorescent materials to widen the wavelength band of the light source on the shortest wavelength side, the emitted light is a color corresponding to light in the short wavelength region. It is possible to prevent the color of the irradiated object from appearing differently when it is irradiated to an object having a.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings.
FIG. 8 is a schematic external view of the illumination device according to the present embodiment. The schematic configuration of the illumination device 11 is the same as that of the conventional LED backlight shown in FIGS. 1 and 2, and a light guide plate 13 (color mixing means) which is a flat transparent medium for confining and guiding light. The sheet or thin plate-like reflecting plate 14 provided on the flat plate on the non-emitting surface side of the light guide plate 13, the diffusion plate 15 provided on the flat plate on the output surface side of the light guide plate 13, and the light guide plate 13 It is comprised from the light source module 16 (about 100 mm in width) installed so that light may inject from an end surface. The light source module 16 includes three types of LEDs R, G, and B that emit red (λ = 680 nm), green (λ = 565 nm), and blue (λ = 450 nm) light, respectively. The light guide plate 13 has a size of, for example, 1000 mm × 1000 mm × 10 mm.

  The R, G, and B lights introduced from the light source module 16 into the light guide plate 13 are mixed in the light guide plate 13 to produce white light. At this time, as described in the above description of the “problem to be solved by the invention”, even if only the light emitted from the three types of LEDs R, G, and B is used, the light in the entire visible wavelength band is used. Since the light cannot be emitted, there is a problem that the color is not reproduced depending on the object. In order to solve this problem, a fluorescent material is used to generate light in a wavelength band that is not emitted from the original LED, and the light that broadens this wavelength band is mixed with the emitted light from other LEDs. The wavelength band of the entire emitted light is broadened. Thereby, ideal light for illumination can be generated efficiently. Such light is difficult to generate even using only light emitted from the three types of LEDs R, G, and B shown by the solid line in FIG. 3, and the fluorescent material shown by the solid line in FIG. It was difficult to generate even if only transmitted light was used.

  The positions where the fluorescent material is provided are (1) the light source module 16, (2) the reflecting plate 14 or the diffusing plate 15, and (3) the extraction pattern portion provided on the non-emitting surface side of the light guide plate 13 (the diffusion shown in FIG. 2) Pattern P) is conceivable. However, when the fluorescent material is provided in the light source module 16, the fluorescent material is irradiated with light before the light of each color is mixed. Therefore, if a fluorescent material is applied only to a portion through which light of a necessary color is transmitted, it is possible to prevent an uncorresponding unnecessary color of light from entering the fluorescent material. Thereby, since the fall of the intensity | strength of the emitted light of the illuminating device 11 whole by permeate | transmitting fluorescent material can be reduced, energy efficiency can be improved.

  A light source whose wavelength band is broadened with a fluorescent material is effective not only for the light guide type surface light source shown in FIG. 8, but also for the indirect illumination shown in FIG. 9 and the direct type illumination shown in FIG. The illumination device 11 shown in FIG. 9 is an indirect illumination comprising a projection light source 30 incorporating three types of LEDs, R, G, and B, and a diffuse reflector 31 that diffusely reflects the light emitted from the projection light source 30. Device. The illuminating device 11 shown in FIG. 10 is a direct type comprising a light source 40 in which three types of LEDs of R, G, and B are arranged in an array and a diffusion plate 41 that diffuses light emitted from the light source 40. It is a lighting device. Also in the case of using these illumination devices 11, it is desirable that the fluorescent material be in a position before light is mixed.

  Next, an installation example of the fluorescent material on the LED emission side will be described with reference to FIG. FIGS. 11 (a1) and (a2) are examples of fluorescent material installation when a plurality of LED chips are molded in a horizontal line. FIGS. 11 (b1), (b2), and (b3) show individual LED chips individually molded. It is an example of fluorescent material installation in the case of being. (A1) and (b1) are fluorescent material installation examples when a fluorescent material is applied to the surface of the LED mold resin. (B2) is a fluorescent material installation example when the fluorescent material is dispersed in the mold resin. a2) and (b3) are examples of fluorescent material installation when a fluorescent material is applied on the LED chip. Below, each installation example is demonstrated.

  In the installation example shown in (a1), different fluorescent materials 22a and 22b corresponding to the respective LED chips 16a, 16b and 16c are formed on the upper surface of the mold resin 21 covering the R, G and B LED chips 16a, 16b and 16c. , 22c is applied. Each fluorescent material 22a, 22b, 22c is disposed at a position where only the light emitted from the LED chips 16a, 16b, 16c passes through. In the installation example shown in (a2), the fluorescent materials 22a, 22b, and 22c are applied to the R, G, and B LED chips 16a, 16b, and 16c themselves, not the mold resin 21 and the mold resin 23, respectively. In both installation examples, before the three colors of light emitted from the R, G, and B LED chips 16a, 16b, and 16c are mixed, the wavelength band of the emitted light is widened using the fluorescent materials 22a, 22b, and 22c. ing. As a result, only the light that can expand the wavelength band of each of the fluorescent materials 22a, 22b, and 22c passes through the fluorescent materials 22a, 22b, and 22c, so that illumination by transmitting these fluorescent materials is performed. It is possible to reduce the intensity drop of the emitted light of the entire apparatus 11.

  In the installation example shown in (b1), the fluorescent material 22c is applied to the surface of the mold resin 23 that covers the B-color LED chip 16c. In the installation example shown in (b2), the fluorescent material 22c is dispersed in the mold resin 23 covering the B-color LED chip 16c. In the installation example shown in (b3), the fluorescent material 22c is applied to the LED chip 16c of B color itself. In any of these installation examples, before the light emitted from the LED chip 16c of B is mixed with the light of other LED chips, the wavelength band of the emitted light is expanded using the fluorescent material 22c. In any of these installation examples (b1), (b2), and (b3), since only the light that can expand the wavelength band of the fluorescent material 22c passes through the fluorescent material 22c, illumination by passing through the fluorescent material 22c. It is possible to reduce the intensity drop of the emitted light of the entire apparatus 11.

  Two or more fluorescent materials may be used for broadening the wavelength band. By using two or more types of fluorescent materials, it is possible to broaden the wavelength band of the emitted light of the LEDs of a plurality of colors, so that the illumination device 11 can be easily compared with the case where broadening is performed using one type of fluorescent material. The wavelength band of the entire emitted light can be broadened. Further, as shown in FIG. 12, the fluorescent material may not be applied to all light sources. 12 (a) and 12 (b) show the case in the light source module 16 when the fluorescent material is separately applied for each LED color, and when the same color LED is divided into the case where the fluorescent material is applied and the case where the fluorescent material is not applied. It is a figure which shows each LED. The G and B LEDs in the light source module 16 shown in (a) are coated with fluorescent materials 22b and 22c that can widen the wavelength band of the emitted light from the G and B LEDs, respectively. No fluorescent material is applied to the R LED. Further, the LEDs of G and B in the light source module 16 shown in (b) are divided into LEDs coated with fluorescent materials 22b and 22c and LEDs not coated even though the colors of the LEDs are the same.

  FIGS. 13A and 13B are diagrams showing spectra when the wavelength bands of the outgoing light from the B LED and the outgoing light from the G LED are expanded, respectively. (A) (1) shows the spectrum of the original light emitted from the B LED, and (2) shows the spectrum when the wavelength band of the emitted light from the B LED is expanded using a fluorescent material. Show. (B) (3) shows the spectrum of the original light emitted from the G LED, and (4) shows the case where the wavelength band of the emitted light from the G LED is expanded using a fluorescent material. The spectrum is shown. As shown in these drawings, the fluorescent material can expand the wavelength band of the original LED only to the long wavelength side. Therefore, for example, the light of (4) in (b) in which the wavelength band of the light emitted from the G LED is expanded cannot cover the wavelength band of (5) belonging to the short wavelength region. For this reason, it is desirable to use a fluorescent material that spreads light on the short wavelength side as the fluorescent material. Thereby, since light in a short wavelength region can be emitted, when the emitted light is irradiated onto the object, it is possible to prevent the color of the irradiated object from changing and appearing. For the same reason, the light source module 16 desirably has an LED on the short wavelength side. FIG. 14 is a diagram illustrating a spectrum when the wavelength band is broadened by the light source module 16 that does not include the LED on the short wavelength side. (6) in the figure shows the spectrum of the original light emitted from the G LED, and (7) shows the spectrum of the light when the wavelength band of the emitted light from the G LED is expanded using a fluorescent material. Indicates. When there is no B LED on the short wavelength side, only light in the wavelength band as shown in FIG. 14 can be emitted even if the wavelength band is broadened. Depending on the application, the wavelength band is expanded only for the light emitted from the R LED, the wavelength band is expanded only for the light emitted from the G LED, or the wavelength band of the light emitted from the G and R LEDs other than B is expanded. There is. Of course, the wavelength band of all light may be expanded.

  The present invention is not limited to the above embodiment, and various modifications can be made. For example, the light source module 16 may be provided with two types of LEDs B and G, and by broadening the wavelength band of the light emitted from these LEDs, the entire light emitted from the illumination device may be broadened. The module 16 may be provided with two types of LEDs, B and R, and by broadening only the wavelength band of the light emitted from the B LED, the entire light emitted from the illumination device may be broadened. Even in such a configuration, light in the short wavelength region can be emitted by spreading the emitted light from the B LED to the long wavelength side, so that irradiation is performed when the emitted light is irradiated onto the object. It is possible to prevent the color of the selected object from changing.

It is a perspective view of the conventional surface light source device. It is sectional drawing of the conventional surface light source device. It is a figure which shows the spectrum of LED of three general primary colors of R, G, B. It is a figure which shows an example of the reflection spectrum of the object which looks yellow under sunlight. It is a figure which shows the reflected light from the yellow object shown by FIG. It is a figure which shows the spectrum of each LED at the time of using 5 types of LED. It is a figure which shows the broadened spectrum at the time of using only one type of LED as an original light source. It is a schematic external view of the illuminating device by one Embodiment of this invention. It is an optical system block diagram of indirect illumination. It is an optical system block diagram of direct type illumination. It is a figure which shows the example of installation of the fluorescent material in the LED emission side. (A) and (b) show each LED in the light source module when the fluorescent material is separately applied for each LED color, and when the LED of the same color is divided into a case where the fluorescent material is applied and a case where the fluorescent material is not applied. FIG. (A) (b) is a figure which shows the spectrum at the time of extending the emitted light from LED of B, and the emitted light from LED of G, respectively. It is a figure which shows the spectrum at the time of broadening a wavelength band with the light source module which does not have LED of the short wavelength side.

Explanation of symbols

11 Illumination device 13 Light guide plate (color mixing means)
16a LED chip (light source, light emitting diode)
16b LED chip (light source, light emitting diode)
16c LED chip (light source, light emitting diode)
22a fluorescent material 22b fluorescent material 22c fluorescent material

Claims (4)

Two or more types of light sources that emit light having different wavelength bands, and
A fluorescent material that broadens the wavelength band of any one of the two or more light sources;
Color mixing means for mixing light from at least one of the two or more types of light sources and light that has passed through the fluorescent material;
The fluorescent material is disposed between the light source and the color mixing means at a position where only light that reacts with the fluorescent material passes,
An illumination apparatus characterized in that light having a wider wavelength band than each of the light sources is emitted by the color mixing means.   2. The illumination device according to claim 1, wherein each of the two or more types of light sources is a light emitting diode that emits one of red, green, and blue light.   The lighting device according to claim 1 or 2, wherein there are two or more types of the fluorescent material.   The lighting device according to claim 3, wherein at least one of the two or more types of fluorescent materials widens the wavelength band of the light source on the shortest wavelength side.

Images