JP2006202533A - Lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting system having an efficient, wide color reproduction range by using a phosphor without greatly affecting the design of a light guide body. <P>SOLUTION: The lighting system comprises a light source, means for obtaining red light, green light and blue light through the use of light from the light source and light emission obtained by excitation of the phosphor by the light source, and a light guide plate that provides a color mixture of the red light, the green light and the blue light to transfer the same, and effects its irradiation in a flat form. The phosphor as a phosphor layer is placed on at least one of the light-irradiating surface, the back surface and the light incident surface of the light guide plate. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an illuminating device used as a front light or a backlight for illuminating a liquid crystal element used for a portable information device, a cellular phone, or the like.

  In recent years, as a display device used for a mobile phone, a mobile computer, or the like, a liquid crystal display device that can obtain high-definition color images with low power consumption is often used. In order to illuminate liquid crystal elements used in these liquid crystal display devices, a light source using a high-intensity white LED is used as a light source for an illumination device.

  In particular, mobile phones use a reflective liquid crystal display device with a large opening and a bright double-sided visible liquid crystal display device capable of displaying image information from both the front and back sides. The white LED used for illumination of these display devices has a green phosphor or a yellow phosphor dispersed in a resin just before the light emitting surface of the blue LED, and the resulting green or yellow light. In general, a structure in which white light is obtained by mixing the blue light with the original blue light is used.

  FIG. 12 is an XY chromaticity diagram illustrating the color reproduction range of a conventional white LED. In the figure, the color triangle connecting the points indicated by RGB is that of the color CRT. By adjusting the luminance of these RGB pixels, all the colors existing inside the color triangle can be expressed. The area of the color triangle of the color CRT is defined as 100%, and the size of the color triangle of a color display device other than the CRT is defined as the NTSC ratio, which is an index of color reproducibility.

  The conventional white LED can reproduce color only on a straight line connecting the chromaticity coordinate 101 of only the emitting blue LED and the chromaticity coordinate 102 of only yellow light obtained by wavelength conversion. Was extremely narrow. Of course, since the yellow phosphor also generates green light and red light components other than yellow by wavelength conversion, it is possible to express red and green colors.

  On the other hand, the phosphor used in the conventional white LED has a high intensity of light applied to the phosphor. Therefore, in order to prevent the light deterioration, the phosphor is formed on the back surface of the light guide plate at a predetermined formation density. What was formed by coating is disclosed (for example, see Patent Document 1).

Furthermore, in order to perform wavelength conversion using a phosphor with a smaller area compared to the method disclosed in the above-mentioned patent document, a layered wavelength converter between the blue LED and the light incident surface of the light guide plate is used. (For example, refer to Patent Document 2).
Japanese Patent Laid-Open No. 7-176794 (2nd page, FIG. 1) Japanese Patent Laid-Open No. 10-269822 (term 3, FIG. 1)

  However, the conventional illumination device that obtains white light by combining a conventional blue LED and a green phosphor or a yellow phosphor has a problem that the color reproduction range is narrow because the red emission intensity is weak.

  In addition, in the conventional lighting device in which the phosphor is applied to the back surface of the light guide plate, the coating concentration must be adjusted according to the light intensity distribution inside the light guide plate. There was a problem that the application conditions had to be matched. Furthermore, since the light propagation characteristic inside the light guide plate is changed by applying the phosphor on the back surface of the light guide plate, it has been difficult to design the light guide plate.

  Furthermore, in a conventional illumination device in which a layered wavelength converter is arranged between the light source and the light incident surface of the light guide plate, the distance between the light source and the wavelength converter is close, so the wavelength converter There was a problem that the distribution of the intensity of the irradiated light was large and the color mixing property was poor.

  An object of the illumination device of the present invention is to provide an illumination device having a wide color reproduction range that does not greatly affect the design of the light guide and is efficient.

  Therefore, the illumination device of the present invention includes a light source, means for obtaining red light, green light, and blue light by light emitted from the light source and light emission obtained by exciting the phosphor with the light source, and the red light. A light guide plate that propagates mixed colors of light, green light, and blue light and irradiates the light in a planar shape, and the phosphor is disposed at one or more of the light irradiation surface, the back surface, or the light incident surface of the light guide plate. ing. Further, two types of phosphor layers are provided: a blue light source and a green light source as light sources, a red phosphor that converts blue light into red light and a red phosphor that converts green light into red light as phosphors. Alternatively, an ultraviolet light source and a blue light source are provided as light sources, and two kinds of phosphor layers are provided as a phosphor, a green phosphor that converts ultraviolet light into green light and a red phosphor that converts ultraviolet light into red light. In addition, among the two types of phosphor layers described above, a phosphor layer that converts light emission having a shorter wavelength is arranged on the light source side.

  Further, the phosphor layer includes a first light-emitting layer in which the first phosphor particles are dispersed in a polymer matrix, and a second light-emitting layer in which the second phosphor particles are dispersed in a polymer matrix. The configuration was distributed above. At this time, the dispersed light emitting layers have different area densities in the plane of the transparent substrate so as to be proportional to the obtained light emission intensity. Alternatively, the dispersed light-emitting layers have different area densities in the plane of the transparent substrate so as to be inversely proportional to the radiation intensity distribution of the light source.

  Furthermore, a light pipe for propagating light from the light source and linearly irradiating the light incident surface of the light guide plate is provided, and the first phosphor particles and the second phosphor particles are dispersed at a predetermined ratio in the light pipe. It was decided. Alternatively, a light pipe that propagates light from the light source and linearly irradiates the light incident surface of the light guide plate, the first phosphor particles are dispersed in the light pipe, the light pipe and the light incident surface of the light guide plate, and It was set as the structure provided with the fluorescent substance layer which distribute | arranged the 2nd fluorescent substance between these. More specifically, a blue light source is used as the light source, a red phosphor layer is used as the first light emitting layer, a green phosphor layer is used as the second light emitting layer, and the light guide plate propagates to the back surface or the light exit surface. The hologram for irradiating the surface with the light to be formed was formed.

  Since the lighting device of the present invention can be a lighting device with a wide color reproduction region and high light utilization efficiency, a good color lighting device for illuminating a plane can be realized. Further, by using this illumination device for a liquid crystal display device, the color reproducibility of the element is improved, and a higher-definition color liquid crystal display device can be realized.

  Further, by using the lighting device of the present invention as a flat lighting device used in a general room, it becomes possible to realize a wall-mounted lighting device with low power consumption, improving the general lighting environment and saving resources. Has the effect of being possible.

  The illumination device of the present invention includes means for obtaining red light, green light, and blue light using light emitted from a light source and light emission obtained by exciting a phosphor, and the red light, green light, and blue light. A light guide plate that propagates mixed colors and irradiates it in a planar shape, and a phosphor is disposed as a phosphor layer at one or more of the light irradiation surface of the light guide plate, the back surface of the light guide plate, or the light incident surface of the light guide plate. Then, using a blue light source and a green light source as light sources, a red phosphor that converts blue light into red light and a red phosphor that converts green light into red light are spatially separated from each other. Furthermore, among the two types of phosphor layers, the phosphor layer that converts light emission with a shorter wavelength was arranged on the light source side. With such a configuration, efficient wavelength conversion could be performed without changing the propagation characteristics of the light guide plate. In addition, by forming the phosphors spatially separated, it is possible to place phosphors with lower wavelength conversion efficiency near the light source, and as a result, it is possible to maximize the color conversion efficiency for each color. became.

  In addition, an ultraviolet light source and a blue light source were used as the light sources, and the phosphor was a green phosphor that converts ultraviolet light into green light and a red phosphor that converts ultraviolet light into red light. With such a configuration, green light emission and red light emission with high light emission efficiency were realized, and an illumination device with a wide color reproduction range could be realized by mixing this with blue light.

  The phosphor layer was formed by printing or coating a light emitting layer in which phosphor particles were dispersed in a polymer matrix on a transparent substrate. The phosphor layer includes a first light emitting layer in which the first phosphor particles are dispersed in the polymer matrix and a second light emitting layer in which the second phosphor particles are dispersed in the polymer matrix. Spatially separated in the upper surface of the molecular substrate. As a result, it was possible to perform wavelength conversion to multiple colors using only one phosphor layer. Since the phosphors do not overlap each other, light absorption by other phosphors can be reduced, and the wavelength conversion efficiency can be substantially improved. At this time, the area where the phosphors are formed is sufficiently small and close to each other, thereby improving the color mixing characteristics and enabling wavelength conversion without color unevenness.

  The area density of the light emitting layer to be dispersed is proportional to the required light emission intensity. As a result, a lighting device having a uniform color mixing ratio could be obtained.

  On the other hand, as a method not using the phosphor layer, the first phosphor particles and the second phosphor particles are preliminarily provided in a light pipe that propagates light from the light source and irradiates the light incident surface of the light guide plate in a linear shape. Mixing and dispersing at a ratio, wavelength conversion and color mixing were simultaneously performed in the light pipe.

  By mixing and dispersing phosphors in the light pipe, wavelength conversion within a uniform and strong light intensity is possible, and wavelength conversion efficiency can be improved. Further, in the light pipe, the light from the light source repeats multiple reflections to form a uniform light field, which makes it possible to improve light color mixing.

  Further, the phosphor layer and the light pipe are used in combination. This is because the first phosphor particles are dispersed in a light pipe that propagates light from the light source and linearly irradiates the light incident surface of the light guide plate, and the second fluorescent material is disposed between the light pipe and the light incident surface of the light guide plate. This is a structure in which a phosphor layer in which a phosphor is arranged is arranged. As a result, the phosphor can be uniformly dispersed in the light pipe, and more uniform color conversion is possible. In addition, since the light intensity applied to the phosphor layer is uniform, the phosphor layer can be uniformly coated with the phosphor layer, and the production thereof becomes easy.

  Embodiments relating to the lighting device of the present invention will be specifically described below with reference to the drawings.

  FIG. 1 schematically shows the configuration of the illumination device of this example. The illumination device shown in FIG. 1 includes a light source 1, a light guide plate 2, a reflection plate 3, a first phosphor layer 4, and a second phosphor layer 5. The light source 1 is a blue LED, and usually two or more are disposed on the light incident surface of the light guide plate. The light guide plate 2 is formed of a transparent polymer such as an acrylic resin, a polycarbonate resin, or a cycloolefin resin, and takes light from the light source 1 from the light incident surface and propagates the light into the inside. In general, a fine prism group or a scattering structure is formed on the light exit surface or the back surface of the light guide plate 2, and uniform light on the surface is irradiated from the light exit surface. In the embodiment shown in FIG. 1, a fine prism group is formed on the back surface of the light guide plate 1, and the light propagating inside is irradiated to the back surface at a predetermined ratio, and the light irradiated from the back surface is reflected by the reflector plate. The light is reflected by 5, passes through the light guide plate 2 again, and is irradiated from the light exit surface of the light guide plate 2.

  As the reflector 5, a transparent base material in which a reflective layer in which Al, Ag or an alloy of Ag and Pd is deposited is formed on a polymer base material, or a white pigment having a high reflectance is mixed therein. Etc. can be used.

  The first phosphor layer 4 and the second phosphor layer 5 are transparent films in which different phosphors are coated on the surface. As shown in FIG. 7, the phosphor layers 4 and 5 are formed by applying a phosphor 7 mixed with a resin binder on a transparent polymer substrate 8. Specifically, in this embodiment, the first phosphor layer 4 is made of a transparent silicon resin binder or an epoxy resin binder on a polyethylene terephthalate (PET) film in which the red phosphor that converts the wavelength of blue light into red light is transparent. It is applied as. The second phosphor layer 5 is formed by coating a green phosphor that converts blue light into green light with a transparent silicon resin binder as a base material on a transparent PET film. As the transparent polymer substrate 8, in addition to PET, a transparent polymer substrate such as an acrylic (PMMA) resin, a polycarbonate (PC) resin, a silicon resin, a fluorine resin, or a cycloolefin resin may be used. it can.

  Since the light with which the second phosphor layer 5 is irradiated has a uniform intensity, the thickness of the phosphor to be coated thereon can be uniformly applied. Further, the phosphor applied on the first phosphor layer 4 may be applied to at least a region irradiated with light from the light source 1.

  On the other hand, when wavelength conversion of light having a shorter wavelength is generally performed, the wavelength conversion efficiency decreases as the wavelength of light obtained by wavelength conversion becomes longer. Therefore, to obtain converted light having the same light intensity, it is necessary to increase the irradiation light intensity as the conversion wavelength increases. Therefore, by arranging the red phosphor in the vicinity of the light source 1, it is possible to efficiently convert blue light into red light. Moreover, since the absorption coefficient with respect to red light of the transparent polymer material which forms the light-guide plate 2 is small compared with green light or blue light, even if the optical path after conversion becomes long, the loss until it irradiates is reduced. be able to.

  On the other hand, since the green phosphor that converts the wavelength of blue light to green light has high wavelength conversion efficiency, the green phosphor is arranged in the second phosphor layer 5 to perform wavelength conversion under uniform light irradiation on the back surface of the light guide plate 2.

  FIG. 11 shows an XY chromaticity diagram for explaining the color reproduction range of the illumination device of the present invention. In the illuminating device of the present invention, the color coordinate 14 by the blue light from the light source, the color coordinate 15 by the green light, and the color coordinate by the red light form a color triangle, and by mixing these colors, the color inside this color triangle is changed. It can be expressed arbitrarily. Although this color triangle is smaller than the color triangle 103 of a general color CRT, it is sufficiently larger than the color triangle of a conventional illumination device using a white LED, and the color reproduction range is widened.

In addition, as a structure of the illuminating device described in the embodiment of the present invention, a light diffusing plate, a prism sheet, or the like is arranged on the light emitting surface of the light guide plate 2 in order to control the luminance distribution and radiation angle of the illumination light. Needless to say, there are many.
(Specific example 1)
In the configuration shown in FIG. 1, three blue LEDs having an emission wavelength of 460 nm were used as light sources. Moreover, what mixed the red fluorescent substance powder mixed with the epoxy resin binder as the 1st fluorescent substance layer 4 was apply | coated using the spin coat. As the red phosphor, a phosphor exhibiting 650 nm emission was used. Moreover, what mixed the green fluorescent substance powder mixed with the epoxy resin binder as the 2nd fluorescent substance layer 5 was apply | coated using the spin coat. As the green phosphor, a phosphor exhibiting 522 nm emission was used.

The NTSC ratio could be arbitrarily changed by adjusting the mixing concentration of each phosphor to the binder and the coating thickness.
(Specific example 2)
In Example 1, instead of inserting the second phosphor layer 5 as a film, a green phosphor 7 was directly applied on the reflector 3 as shown in FIG. 8 to form a second phosphor layer. Moreover, the fluorescent substance used for this 2nd fluorescent substance layer used the fluorescent substance which shows light emission of 535 nm. By adopting such a configuration, the loss of surface reflection is reduced as compared with the case where the second phosphor layer is formed into a film, and illumination with higher luminance is possible. Also in this specific example, the color reproduction range is wider than when a conventional white LED is used.

  FIG. 2 schematically shows the illumination device of this example. In Example 2, the first phosphor layer 4 was disposed on the back surface of the light guide plate 2, and the second phosphor layer 5 was disposed on the back surface of the light guide plate 2. A blue LED having an emission wavelength of 460 nm was used as the light source. For the first phosphor layer 4, a phosphor exhibiting 615 nm emission was used as the red phosphor, and as the second phosphor layer 5, a green phosphor exhibiting 522 nm emission was used.

  With such a configuration, it is possible to provide a lighting device with a wide color expression area. In addition, since the blue light passing through the first phosphor layer 4 is used twice by irradiation light from the light guide plate 2 side and reflected light from the reflection plate 3 side, the wavelength of the blue light is converted only once. In comparison with the above, the phosphor concentration contained in the first light guide layer 4 can be halved.

  In this embodiment, since the light propagating through the light guide plate 2 is substantially only blue light, the structural design of the light guide plate for irradiating from the light exit surface can be facilitated, and the illumination efficiency can be improved. It was possible to improve the design delivery time. In addition, as a means for taking out and irradiating light propagating through the light guide plate 2 to the outside, this makes it possible to efficiently generate holograms other than using a fine prism group or a fine scattering structure on the light exit surface or back surface of the light guide plate 2. It became possible to use. This hologram can be easily produced by transferring a pattern obtained by two-beam interference fringes by lithography, or by forming a computer generated hologram such as a Lippmann hologram by lithography.

  Also in this embodiment, the first phosphor layer 4 can be directly formed on the reflection surface of the reflector 3 as shown in the second specific example of the first embodiment.

  FIG. 3 schematically shows the illumination device of this example. The difference between the present embodiment and the second embodiment is that both the first phosphor layer 4 and the second phosphor layer 5 are arranged on the light emitting surface side of the light guide plate 2. Since the light emitted from the light guide plate 2 has a light intensity distribution with a uniformity of 70% or more, the wavelength conversion by the first phosphor layer 4 and the second phosphor layer 5 is performed by such an arrangement. The light emission intensity obtained by this can be made uniform, and the color mixing property can be improved. Furthermore, the wavelength conversion efficiency could be improved by using a red phosphor for the first phosphor layer 4 and a green phosphor for the second phosphor layer 5.

  FIG. 4 schematically shows the illumination device of this example. In the present embodiment, the first phosphor layer 4 and the second phosphor layer 5 are disposed between the light source 1 and the light incident surface of the light guide plate 2. Also in this case, the wavelength conversion efficiency could be improved by using a red phosphor for the first phosphor layer 4 and a green phosphor for the second phosphor layer 5.

  In this case, since the first phosphor layer 4 and the second phosphor layer 5 are close to the light source 1, the light intensity distribution applied to these phosphor layers is increased. For this reason, the light intensity of the light emitted from the phosphor layer after being wavelength-converted becomes uneven when the colors are mixed inside the light guide plate because the portion where the light emission intensity is high becomes strong. Therefore, light emission and wavelength conversion are performed by reducing the thickness of the phosphor applied to the phosphor layer at the portion where the light emission intensity is high and increasing the thickness of the phosphor applied at the phosphor layer at the portion where the light emission intensity is low. The ratio with the emitted light obtained in step 1 was made almost constant.

  A light source in which an ultraviolet LED that emits near ultraviolet light and a blue LED that emits blue light are arranged close to each other can be used as the light source 1. An ultraviolet LED formed of a material such as GaN has a light emission wavelength of 365 nm, for example, and has high excitation energy for the phosphor, so that highly efficient wavelength conversion can be performed. However, since the ultraviolet rays are greatly absorbed by the constituent members of the lighting device such as the polymer material constituting the light guide plate 2, it is preferable to propagate the ultraviolet rays into the light guide plate to uniformly excite the phosphor in a wide area. Absent. Therefore, it is efficient to arrange a phosphor layer in the gap between the ultraviolet LED and the light guide plate 2 as shown in FIG. 4 and to propagate the visible light after conversion in the light guide plate.

  FIG. 9 is a plan view schematically showing the concentration distribution of the phosphor applied to the first phosphor layer 4 and the second phosphor layer 5 when three light sources are arranged in parallel. In FIG. 9, the concentration of the phosphor increases in the order of regions 9, 10, and 11. The region 9 corresponds to the luminance center of the light source, and the irradiation light intensity is the strongest, and the irradiation light intensity decreases as the distance from the luminance center increases. In general, the stronger the irradiation light intensity of the phosphor, the higher the wavelength conversion efficiency and the more the converted light component. Therefore, it is possible to obtain illumination light with a uniform color distribution by increasing the concentration of the phosphor as the distance from the luminance center of the light source increases.

  Such a region can be easily produced by sequentially printing base materials having different phosphor concentrations using a printing plate corresponding to each region by screen printing or offset printing.

  In the figure, the area is divided into three areas 9, 10, and 11 corresponding to each light source. However, the color distribution can be improved by dividing the area into more areas.

Thus, by providing a distribution in the phosphor concentrations formed in the first phosphor layer 4 and the second phosphor layer 5 in FIG. 4, it is possible to obtain an illumination device with good color reproducibility and good color mixing. It was.
(Concrete example)
In FIG. 4, three light sources 1 in which ultraviolet LEDs and blue LEDs are close to each other and sealed in one package are arranged in parallel. The emission wavelength of the ultraviolet LED was 365 nm, and the emission wavelength of the blue LED was 470 nm.

  A red phosphor was screen printed on the first phosphor layer 4 with the distribution shown in FIG. The red phosphor was mixed and dispersed in a silicon resin base material to obtain a printing material having five levels of density. Then, printing and curing were repeated in order from the outside of the region to form the first phosphor layer 4. Further, as the second phosphor layer 5, a green phosphor printed and cured in the same manner as the first phosphor layer 4 was used. In this way, the red LED and the green light are excited by the ultraviolet LED and mixed with the blue light from the blue LED, so that an illumination device having a wide color reproduction range and a good color mixing property has been achieved. . In particular, the ultraviolet light used for light emission has no effect on color reproduction, and only the mixed color of excited red light and green light and blue light from a blue light source needs to be considered. We were able to.

  Note that the ultraviolet light promotes deterioration of the polymer material that is a constituent member of the lighting device, and the liquid crystal deteriorates when the liquid crystal device is irradiated with light mixed with ultraviolet light. In addition, it has an adverse effect on the eyes of the observer. Therefore, although not explicitly shown in FIG. 4, in this specific example, an ultraviolet absorbing film is inserted between the second phosphor layer 5 and the light incident surface of the light guide plate 2.

  FIG. 5 schematically shows a perspective view of the present embodiment. In FIG. 5, blue light sources 1 a and 1 b are arranged on both side ends of the light pipe 6. Light emitted from these blue light sources propagates through the inside of the light pipe 6 to be uniformed, and is deflected by a prism formed on the surface of the light pipe 2 facing the light guide plate 2 or on the opposite surface thereof. The light incident surface is uniformly irradiated and guided into the light guide plate 2.

  In the illuminating device of this embodiment, a uniform wavelength conversion and color mixing are realized by mixing a red phosphor in the light pipe 6 and converting the wavelength of blue light into red light inside the light pipe 6. In addition, the blue light is repeatedly reflected in the light pipe 6 and the light intensity is strong, so that efficient wavelength conversion is possible.

  On the other hand, the second phosphor layer 5 is disposed on the back surface of the light guide plate 2, and the green phosphor is uniformly formed on the surface or uniformly mixed therein.

  By adopting such a configuration, it was possible to obtain an illumination device with good color reproducibility and excellent color mixing.

  FIG. 6 schematically shows a perspective view of this embodiment. 6 differs from the fifth embodiment in that the second phosphor layer 5 is inserted between the light pipe 6 and the light incident surface of the light guide plate 2.

  As described in the fifth embodiment, the red phosphor mixed in the inside of the light pipe 6 efficiently converts the wavelength of the blue light into red light by the uniform and strong blue light inside the light pipe 6. Also, blue light and red light can be mixed sufficiently uniformly inside the light pipe.

  Furthermore, since the light emitted from the light pipe 6 to the light incident surface side of the light guide plate 2 is uniform, the phosphor applied to the surface of the second phosphor layer 5 or mixed therein may be uniform. Further, as compared with the fifth embodiment, since the intensity of the light applied to the second phosphor layer 5 is strong, the efficiency of converting blue light into green light can be increased. And since the area of the 2nd fluorescent substance layer 5 can be made small compared with Example 5, the quantity of the fluorescent substance to be used can be reduced and the manufacturing cost of an illuminating device can be reduced.

  In this way, also in this example, an illuminating device having good color reproducibility and excellent color mixing could be realized.

  In Example 6 shown in FIG. 6, the phosphor applied to the surface of the second phosphor layer 5 may be uniform and uniform. At this time, for example, when blue light is wavelength-converted with a red phosphor to obtain red light, energy required for wavelength conversion is absorbed and the intensity decreases. It is not efficient to convert the wavelength of blue light into green light using the same blue light and a green phosphor.

  Therefore, in the present embodiment, in the configuration shown in FIG. 6, the red phosphor and the green phosphor are divided into regions on the second phosphor layer 5 and selectively printed to effectively use light emission. Specifically, as shown in FIG. 10, a pattern in which a red phosphor coating region 12 and a green phosphor coating region 13 are separated from each other on a transparent polymer substrate 8 is used. The body and the green phosphor were mixed and dispersed in a resin base material and screen printed. By doing so, it is possible to efficiently perform wavelength conversion of two wavelengths from one light source by using one phosphor layer without mixing and dispersing phosphors inside the light pipe 6. . In addition, each phosphor can absorb light emitted from each other and can perform wavelength conversion with light having a good intensity without weakening each other.

  In FIG. 10, the shape of the area to be divided is not necessarily rectangular, and may be a dot shape or a polygonal shape. The intensity of the light subjected to wavelength conversion can be easily adjusted by adjusting the area density of the divided regions. Further, the thickness of the phosphor to be printed and the concentration of the phosphor dispersed in the base material may be changed.

  In order to achieve sufficient color mixing, the print area should be as small as possible. By using screen printing, offset printing, or inkjet printing, the size of the printing area can be adjusted to an arbitrary size of 50 to 100 μm, and sufficient color mixing is possible.

  It is possible to easily form a phosphor layer substantially having a phosphor concentration distribution as shown in FIG. 9 by changing the size of the printing region to change the phosphor concentration. Become.

  Further, it goes without saying that the formation of the phosphor forming regions dispersed in this manner can be applied to cases other than arranging the phosphor layer in the gap between the light source and the light incident surface of the light guide plate.

It is a schematic diagram which shows the structure of the illuminating device by this invention. It is a schematic diagram which shows the structure of the illuminating device by this invention. It is a schematic diagram which shows the structure of the illuminating device by this invention. It is a schematic diagram which shows the structure of the illuminating device by this invention. It is a schematic diagram which shows the structure of the illuminating device by this invention. It is a schematic diagram which shows the structure of the illuminating device by this invention. It is sectional drawing which shows typically the structure of the fluorescent substance layer used by this invention. It is sectional drawing which shows typically the structure of the fluorescent substance layer used by this invention. It is a top view which shows typically the structure of the fluorescent substance layer used by this invention. It is a top view which shows typically the structure of the fluorescent substance layer used by this invention. It is a chromaticity diagram explaining the color reproduction range of the illuminating device of this invention. It is a chromaticity diagram showing the color reproduction range of the illuminating device using the conventional white LED.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Light guide plate 3 Reflector 4 First phosphor layer 5 Second phosphor layer 6 Light pipe 7 Phosphor 8 Transparent polymer substrate

Claims (10)

  A light source, light from the light source, and means for obtaining red light, green light, and blue light by light emission obtained by exciting a phosphor with the light source, and the red light, green light, and blue light. A light guide plate that propagates mixed colors and irradiates in a planar shape, and the phosphor is disposed at one or more of a light irradiation surface of the light guide plate, a rear surface of the light guide plate, or a light incident surface of the light guide plate. An illumination device comprising a phosphor layer.   The light source includes a blue light source and a green light source, and the phosphor includes two types of phosphor layers: a red phosphor that converts blue light into red light and a red phosphor that converts green light into red light. The lighting device according to claim 1.   The light source includes an ultraviolet light source and a blue light source, and the phosphor includes two types of phosphor layers: a green phosphor that converts ultraviolet light into green light and a red phosphor that converts ultraviolet light into red light. The lighting device according to claim 1.   4. The illumination device according to claim 2, wherein, of the two types of phosphor layers, a phosphor layer that converts light emission having a shorter wavelength is disposed on a light source side. 5.   The phosphor layer includes a first light-emitting layer in which first phosphor particles are dispersed in a polymer matrix, and a second light-emitting layer in which second phosphor particles are dispersed in a polymer matrix on a transparent substrate. The illumination device according to claim 1, wherein the illumination device has a configuration distributed to each other.   The lighting device according to claim 5, wherein the dispersed light emitting layers have different area densities in the plane of the transparent substrate so as to be proportional to the obtained light emission intensity.   The lighting device according to claim 5, wherein the dispersed light emitting layers have different area densities in the plane of the transparent substrate so as to be inversely proportional to a radiation intensity distribution of the light source.   A light pipe that propagates light from the light source and linearly irradiates the light incident surface of the light guide plate, and the light pipe has a predetermined ratio of the first phosphor particles and the second phosphor particles. The lighting device according to claim 5, wherein the lighting device is dispersed by a light source.   A light pipe that propagates light from the light source and linearly irradiates a light incident surface of the light guide plate, disperses the first phosphor particles in the light pipe, and light of the light pipe and the light guide plate; The illumination device according to claim 5, further comprising a phosphor layer in which a second phosphor is disposed between the incident surface and the incident surface.   A blue light source is used as the light source, a red phosphor layer is used as the first light emitting layer, a green phosphor layer is used as the second light emitting layer, and light propagates through the light guide plate to the back surface or the light exit surface of the light guide plate. The illumination device according to claim 5, wherein a hologram for irradiating the surface is formed.

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