JP2008108523A - Lighting system, and display device equipped with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem where, since green light is included in an excitation wavelength in a nitride phosphor or chalcogenide-based phosphor used as a red phosphor, when white light is obtained by using a conversion body with a red phosphor mixed with a green phosphor, luminance efficiency is deteriorated as a result and, in the case of a structure provided with a fluorescent film between a light source and a liquid crystal display, there is a problem of color change and luminance change due to a visual angle. <P>SOLUTION: A phosphor is arranged to reflect light of a blue or ultraviolet LED. A phosphor converting light to green light by blue or ultraviolet excitation, and a phosphor converting light to red light are arranged in areas different from each other. In addition, the phosphor is structured to be isolated from moisture in the outside air. Thereby, a long-life and high-luminance lighting system can be provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an illumination device that illuminates a non-self-luminous display element, and a display device used in an electronic apparatus. In particular, the present invention relates to a liquid crystal display device used for a portable information device, a mobile phone, a television, and the like, and an illumination device such as a front light and a backlight for illuminating a display element.

  2. Description of the Related Art Liquid crystal display devices that can obtain high-definition color images with low power consumption are often used for display devices used in recent mobile phones and mobile computers. Since the liquid crystal element used in the liquid crystal display device is a non-self-luminous type, the liquid crystal element is illuminated using an illumination device that uses a high-intensity white LED as a light source.

  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. A white LED used for illumination of these display elements has a configuration in which a resin in which a yellow phosphor is dispersed is provided immediately before a light emitting surface of a blue LED such as an InGaN-based or GaN-based LED. According to this configuration, white light can be obtained by mixing yellow light and original blue light. As a phosphor that converts blue light into yellow light, a YAG phosphor obtained by doping a rare earth element into YAG (yttrium, aluminum, garnet) is well known. There is also known a method in which red and green light emitting phosphors are mixed instead of YAG phosphors, and white light is generated by additive color mixture of blue, red and green. As phosphors that convert blue light into green light and red light with relatively high efficiency, chalcogenide phosphors and nitride phosphors doped with rare earth are well known. In addition, a plurality of light emitting elements that emit light having a wavelength equal to or less than the wavelength of blue light are arranged on a printed circuit board having an arbitrary shape and area on which a circuit is formed, and each light emitting element has a translucency containing a wavelength conversion material An LED display device coated with a resin is disclosed.

In addition, a method of synthesizing white light by disposing a transparent film having a wavelength conversion material between the light guide plate of the backlight and the LCD panel, instead of potting the wavelength conversion material on the blue LED, is disclosed. (For example, refer to Patent Document 1).
Japanese Patent No. 3417384 (1 page, Fig. 1)

  An LCD module having high color reproducibility can be realized by performing additive color mixing by combining two or more kinds of phosphors that are converted into green light, red light, yellow light, or the like by blue or ultraviolet light excitation. However, as disclosed in the prior art, when the red phosphor and the green phosphor are mixed and applied on a transparent film, the light emitted from the green phosphor is used to excite the red phosphor. Or the in-plane particle density increases too much, and there is a problem that it is difficult to increase the luminance.

  In addition, sulfide phosphors widely known as green and red phosphors excited by blue light are very sensitive to moisture, and the LED package is configured to pot silicon or epoxy resin mixed with sulfide phosphors. In this case, the moisture-proof performance of the resin is insufficient. For example, if the resin is left for 100 hours under high-temperature and high-humidity conditions, only a level of reliability that can reduce the luminance by half can be secured. The cause of the decrease in luminance is deterioration of the phosphor itself and a decrease in reflectance due to a chemical reaction of a reflective layer of, for example, silver or aluminum inside the LED package.

  In addition, in the case of a configuration in which a white film is synthesized by installing a film having a fluorescent material between the light guide plate of the backlight and the liquid crystal display as in the configuration of the prior art, the blue light emitted from the light guide plate Since the direction and the ratio of the light color-converted by the fluorescent material differ depending on the viewing angle, a problem of color change depending on the viewing angle occurs, and high luminance efficiency has not been obtained. A conventional lighting device will be described with reference to FIG. Light emitted from the light emitting diode package 1 exits through the light guide 3 and the fluorescent film 12. At that time, the light not hitting the phosphor 13 is emitted at an angle from the light guide 3 as it is, but the light hitting the phosphor 13 is reflected and is emitted in the opposite direction to the light that did not appear. In FIG. 6, a component that is emitted from the light guide 3 and does not appear on the phosphor 13 is represented by a solid arrow, and a component whose direction has changed on the phosphor 13 is represented by a dotted arrow. For example, when blue light is used as a light source and whitening is attempted with a yellow phosphor, the light output direction from the light guide 3 appears to be very blue and the opposite direction appears to be yellow. Will occur. For this reason, a diffusion sheet is arranged to mix colors, or a diffusion function is added to the fluorescent film 12, but if the diffusibility is made too strong, it causes a reduction in luminance.

  Moreover, in the case of the structure of a prior art, when the size of a liquid crystal display device becomes large, the fluorescent film of an equivalent magnitude | size will be needed. Compared with a structure in which a phosphor is provided in a light emitting diode package, the amount of necessary phosphor increases and the film area also increases. Therefore, particularly in the case of a large product, it is disadvantageous in terms of cost.

  In addition, the additive color mixture of two colors of blue LED and YAG phosphor (pseudo white LED) has few light components in the wavelength region of 600 nm or more. This hinders the realization of an LCD module having high color reproducibility. In general, in the current color filter technology, when a pseudo white LED is used as a light source, it is very difficult to exceed the NTSC ratio of 100%.

  Further, a backlight using a conventional white LED is used in combination with an LCD panel, but the backlight of an optimal color balance varies depending on the optical specifications of the LCD panel. It is difficult to control the color adjustment by the amount of phosphor added to the LED for each LCD panel, and the current situation is to rank and cope with the chromaticity of the masses that are in the mass production variation. A light source with optimal chromaticity cannot always be provided.

  Therefore, the lighting device of the present invention is a lighting device in which light emitted from the blue light emitting element emits light by using a light guide, and is provided in an optical path between the blue light emitting element and the light emitting surface of the lighting device. And a green light emitting phosphor provided in an optical path between the red light emitting phosphor and the light emitting surface of the illumination device. Here, the red light-emitting phosphor is a phosphor that converts red light by blue excitation, and the green light-emitting phosphor is a phosphor that converts green light by blue excitation.

  The green light-emitting phosphor and the red light-emitting phosphor are disposed separately, and light emission from the green phosphor is not used as excitation light of the red phosphor, and the light emission efficiency as the lighting device is increased. Further, the blue light emitting element, the green light emitting phosphor and the red light emitting phosphor are completely separated.

  Either the green light-emitting phosphor or the red light-emitting phosphor, or both, is structured to be shielded from the moisture of the outside air by the water-impermeable material.

  At this time, the green light-emitting phosphor and the red light-emitting phosphor are not disposed between the light guide plate and the liquid crystal display, but are disposed so as to reflect light from the light source in an arbitrary direction.

  The display device of the present invention includes the illumination device having any one of the above-described configurations and a non-self-luminous display element provided on the irradiation surface side of the illumination device.

  The lighting device of the present invention can obtain white light by multicolor additive color mixing. At this time, by separating the plurality of phosphors, light emitted from the green phosphor is not used as excitation light for the red phosphor. In addition, since the red phosphor and the green phosphor are shielded from the moisture of the outside air by the non-water-permeable material, an illuminating device having a long lifetime and a high light emitting effect can be realized. Further, by arranging the phosphor at a position where light from the light source is reflected, a color change due to a viewing angle as a backlight is prevented and a luminance increase is achieved.

  By combining the lighting device of the present invention with an LCD panel, a liquid crystal display device with high color reproducibility, high luminance and long life can be realized.

  The illuminating device of the present invention relates to an illuminating device in which light emitted from a light emitting element is surface-emitted using a light guide, and the light emitting element emits light in an optical path between the light emitting element and a light exit surface of the light guide. A reflecting body is provided, and the reflecting body has a wavelength conversion function for converting the wavelength of light emitted from the light emitting element. That is, a plurality of wavelength converters that perform wavelength conversion to light having different peak wavelengths are arranged in different areas without being mixed at positions that reflect light emitted from the light emitting element.

  Further, the reflector includes a first wavelength converter that converts light emitted from the light emitting element into light having a first peak wavelength, and wavelength conversion of light emitted from the light emitting element to light having a wavelength shorter than the first peak wavelength. The second wavelength converter is configured to exist independently, and the area occupied by the second wavelength converter is smaller than the area of the first wavelength converter. That is, the first wavelength converter and the second wavelength converter are arranged in different areas without mixing, and light emitted from the second wavelength converter is difficult to hit the first wavelength converter. .

  As a light emitting element, a blue light emitting element having a peak wavelength of 450 nm to 480 nm is used, a red phosphor that excites blue light as a first wavelength converter and converts it into red light, and blue light as a second wavelength converter. A green phosphor that is excited and converted to green light can be used. Alternatively, an ultraviolet light emitting element having a peak wavelength of 360 nm to 440 nm is used as the light emitting element, a red phosphor that excites ultraviolet light as the first wavelength converter and converts it into red light, and ultraviolet light as the second wavelength converter. A green phosphor that excites and converts to green light can be used.

  Examples of the green light emitting phosphor that converts green light by blue excitation include a group II metal thiogallate and a rare earth dopant, a group consisting of an oxide and a rare earth dopant, a group consisting of Sr-SION and a rare earth dopant, and the like. Those having a luminance efficiency higher than that of YAG phosphors are suitable. As the red light-emitting phosphor that converts red light by blue excitation, those composed of a nitride and a rare earth dopant and those composed of a sulfide and a rare earth dopant are suitable.

  Furthermore, a resin layer in which transparent beads of acrylic or silica are dispersed may be provided on the light emitting surface side from the second wavelength converter. Scattering function can be added by transparent beads. These transparent beads may be used by mixing with a wavelength converter.

  In particular, the sulfide-based phosphor particles have the property of reacting with moisture and reducing the color conversion efficiency. Therefore, it is conceivable to cover with a transparent resin with low water permeability such as silicon or fluorine, but a material having high water permeability with a polymer-based transparent material is rare, even if very expensive, Use for industrial applications is difficult. Therefore, the phosphor can be isolated from moisture in the outside air by sandwiching the phosphor with a non-water-permeable film such as moisture-proof PET on which a metal thin film is deposited. In the present invention, instead of using the same moisture-proof PET on both sides, a reflector is formed by using a reflection film provided with a reflection film made of aluminum or silver on one side. The reflector having such a configuration is referred to as a fluorescent reflection film. By using a single fluorescent reflection film, the air layer in the optical path is reduced and the light utilization efficiency is increased. In addition, the thickness of the metal film of the transparent moisture-proof film is several mm, but the thickness of the metal film used for the reflective film is about 100 nm, which is very thick compared to the transparent moisture-proof film, and the moisture-proof effect is also very high. It is high.

Further, the reliability of the package is improved by coating the sulfide-based phosphor particles with a non-water-permeable transparent material or using a nitride phosphor. As the non-water-permeable transparent material, SiO ₂ , silicon resin, cycloolefin resin, fluorine resin, or epoxy resin can be used. When a nitride-based phosphor is used, it may not be coated.

  Furthermore, the display device of the present invention includes the illumination device having any one of the above-described configurations and a non-self-luminous display element provided on the light emitting surface side of the illumination device. That is, a display device that illuminates a non-self-luminous display element using light emitted from a light emitting element, and a plurality of wavelength converters that perform wavelength conversion to light having different peak wavelengths at positions that reflect light emitted from the light emitting element Are arranged in different areas without mixing. The display device having such a structure has a long life, high luminance, high color reproducibility, and excellent display quality.

  The illuminating device of a present Example is demonstrated using FIGS. 1-5 and FIG. 7, FIG. 1 is a schematic diagram which shows the outline | summary of the illuminating device of a present Example. In this embodiment, the light emitting diode package 1 is a blue light emitting package in which a resin is potted on a blue LED element. As shown in FIG. 1, a light emitting diode package 1 is formed by soldering on a terminal portion on a circuit board 4. The light emitting diode package 1 emits blue light or ultraviolet light having a spectrum whose peak is in the range of 360 nm to 480 nm. The light emitted from the light emitting diode package 1 enters the light guide 3, is color-converted when reflected by the fluorescent reflection film 5, exits from the light exit surface of the light guide 3, and uniformly emits light through the diffusion film 2. Here, a flexible printed circuit board or a glass epoxy board is used for the circuit board 4, and a transparent resin such as polycarbonate or acrylic is used for the material of the light guide 3. The diffusion film 2 is not always necessary, and may not be required as long as the light guide itself can control the uniformity. In the case of a light guide generally called a V-groove method, a lens sheet called BEF made by Sumitomo 3M is often installed on a diffusion film. Alternatively, a reverse prism sheet made by Mitsubishi Rayon may be used. In any case, the optical design is made so as to take as much light component in the light exit surface direction of the light guide as possible.

  FIG. 2 is a schematic diagram showing the configuration of the fluorescent reflective film 5, in which the fluorescent layer 7 is selectively printed on the reflective film 8 and the transparent moisture-proof layer 6 is laminated using an adhesive or a hot melt agent. did. As the reflection film 8, a film obtained by dry-laminating a film obtained by depositing an aluminum layer of about 100 nm on a transparent film such as 25 μm PET and a film obtained by depositing a silver layer of about 100 nm on a transparent film such as 25 μm PET was used. In general, there are a wide variety of configurations as a silver reflective film, for example, a configuration using white PET instead of a film on which aluminum is deposited, a configuration using only a silver layer, and the like. In this embodiment, it is an essential condition that a metal layer as thick as possible exists. This is because if the thickness is large, defects (holes) are inevitably reduced. In that sense, a multilayer film is ideal. For example, using ESR manufactured by Sumitomo 3M is an ideal material in terms of moisture resistance and optical characteristics because of its multilayer structure and high reflection characteristics. However, there are disadvantages such as being expensive and unable to increase the area. ESR is an abbreviation for Enhanced-Special-Reflector, and is a film having a high reflectance in the visible light range due to a multilayer film structure using a polyester resin. This product was developed for the reflective sheet under the light guide plate of the backlight. The loss during reflection is small, and the screen brightness can be greatly improved by effectively using the light source.

A film (fluorescent layer 7) in which a phosphor (wavelength conversion material) is dispersed in a transparent resin such as medium is selectively printed on the reflection film 8 described above. As a printing technique, a masking technique such as screen printing can be considered. As the transparent resin, an acrylic UV curable adhesive was used with emphasis on the transmittance. However, if importance is placed on reliability, urethane, fluorine-based or silicon-based resin may be selected. In addition, there is no functional problem even if a thermosetting type or a two-component mixed type curing mode is used due to the process. As the phosphor, green phosphor particles, yellow phosphor particles, red phosphor particles, and blue phosphor particles can be considered. As green and blue phosphor particles, strontium thiogallate activated by rare earths, oxides and nitride phosphors are widely known and suitable. In the case of a light source close to ultraviolet light, BaMgAl ₁₀ O ₁₇ : Eu, Mn, ZnS is suitable. As the yellow phosphor particles, YAG phosphors widely used for white LEDs are well known. As the red phosphor particles, chalcogenide compound phosphor fine particles can be used. In particular, a fluorescent material composed of a sulfide such as CaS or SrS and a rare earth dopant, or a fluorescent material composed of a nitride phosphor and a rare earth dopant has high light conversion efficiency. However, in the case of a sulfide phosphor, it may react with moisture to generate hydrogen sulfide. In that case, the reflective film inside the LED causes a chemical reaction, and the luminance characteristics are remarkably deteriorated. Therefore, when using a sulfide phosphor, the phosphor itself may be covered with a transparent water-impermeable material such as SiO ₂ . In addition, organic fluorescent materials are also available in various colors, and they should be used properly according to TPO. However, in the case of organic systems, attention is necessary because they are often inferior to inorganic systems in terms of life.

  A hot-melt resin is printed on the entire surface of the fluorescent layer 7 to form the adhesive layer 11, and the moisture-proof film 6 is hot-laminated. As the moisture-proof film, a film obtained by depositing silicon oxide or the like on a transparent film such as PET is widely known. In addition, there are films such as multilayer films and materials such as ZEONOR in order to further improve the reliability. Further, the moisture-proof film 6 with a hot-melt resin may be laminated, or the moisture-proof film 6 and the fluorescent layer 7 may be bonded by a pressure-sensitive adhesive or a wet process instead of hot-melt. However, when viewed from above, the fluorescent layer 7 exists between the moisture-proof film 6 and the reflective film 8 and it appears as if the fluorescent layer 7 is shielded from the outside air, but when viewed in cross section, the fluorescent layer 7 is exposed. End up. In the case of FIG. 2, in the cross section viewed from the right direction, the fluorescent layer 7 is covered with the adhesive layer 11, but in the cross section viewed from the left, the fluorescent layer 7 is exposed. Therefore, the fluorescent layer 7 is printed on the inner side of the outer shape of the film. As a result, the adhesive layer 11 exists between the fluorescent layer 7 and the outside air as shown in the right side of FIG. 2, and the fluorescent layer 7 is shielded from the outside air. At this time, the larger the width of the adhesive layer 11 as viewed from above, the farther the phosphor layer 7 is from the outside air, and the higher the reliability.

  3 and 4 are front views when the green fluorescent layer 9 and the red fluorescent layer 10 are printed in a stripe shape as the fluorescent layer 7. In either case, the four sides are covered with the adhesive layer 11 and the fluorescent layer is shielded from the outside air. Strontium thiogallate was used as the phosphor particles of the green phosphor layer 9, and calcium sulfide was used as the phosphor particles of the red phosphor layer 10. FIG. 3 shows a case of stripes perpendicular to the light emitting diode package 1, and FIG. 4 shows a case of horizontally long stripes parallel to the light emitting diode package 1. After the light from the light emitting diode package 1 enters the light guide, it is basically guided in the light incident direction while gradually diffusing in the lateral direction. In that case, the light hitting the green fluorescent layer 9 emits green, but if the emitted green light hits the red layer 10, it is further converted into red light, resulting in double conversion and color conversion. It will cause a decrease in efficiency. Therefore, as shown in FIG. 3, by arranging the stripes vertically from the side of the light source, the possibility that the light once converted to green again hits the red fluorescent layer 10 is reduced, and the brightness is increased. On the other hand, if they are arranged in stripes parallel to the light source as shown in FIG. 4, when a part of the emitted green light bounces back again, the possibility of hitting the red fluorescent layer 10 increases, and the luminance decreases. Arise. For the same reason, the area occupied by the red fluorescent layer 10 should be as small as possible than the area occupied by the green fluorescent layer 9. In this example, the green phosphor layer was arranged in stripes with a width of 50 μm and a red phosphor layer having a width of 20 μm. In consideration of color mixing, it is preferable that the width of the fluorescent layer is fine. However, in the case of screen printing, for example, the width or pitch is about 20 μm. If the width is 20 μm, it is considered that the colors are sufficiently mixed.

  FIG. 5 is a front view when the green fluorescent layer 9 and the red fluorescent layer 10 are printed in a dot matrix. There is a merit that color mixing is easier than in the case of a stripe shape. In addition to this shape, a method of arranging in a delta arrangement or a honeycomb shape is also conceivable. Further, the green fluorescent layers 9 and the red fluorescent layers 10 do not have to be arranged alternately, and may be random. For example, if only the central portion has a green area, the central portion can have a greenish color scheme, and color shading can be selectively given as desired.

  Moreover, it is not necessary to form the fluorescent reflection film 5 with a plurality of color fluorescent layers, and it may be a single color. For example, even when a red phosphor is included in the light emitting diode package 1 and the fluorescent reflection film 5 is only a green fluorescent layer, a high-luminance white illumination device can be realized.

  FIG. 7 is a schematic cross-sectional view of the illumination device of this example. Of the light incident on the light guide 3 from the light emitting diode package 1, a part of the light is color-converted by the reflective fluorescent film 5 and guided in the light guide 3 in the direction opposite to the light emitting diode package side. The light is emitted on the surface where the diffusion film 2 is present. As described above, one of the causes of color change due to luminance reduction and viewing angle, which is a problem to be solved by the present invention, is to convert light emitted from the light guide 3 in its optical path as in Patent Document 1. This is because there is a difference between the traveling direction of light from the light source and the traveling direction of light emitted by the phosphor. In the case of the present embodiment, the direction of light emitted from the phosphor particles of the reflective fluorescent film 5 and the direction of light emitted from the light guide 3 are basically the same. It can be secured, and the problem of color change due to viewing angle is also solved. Further, if a material having a high reflectance such as a white pet or metal is used for the frame 15, leakage light can be used efficiently.

  A structure of a liquid crystal display device using the above-described illumination device is schematically shown in FIG. As illustrated, the liquid crystal panel 17 is disposed on the light emitting surface of the lighting device. The liquid crystal panel 17 has a color filter that is color-tuned in accordance with the light source spectrum emitted by the illumination device. Alternatively, a plurality of wavelength converters are set according to the emission color of the light source package and the color filter of the liquid crystal panel. Thereby, a liquid crystal display device with very high luminance and high color reproducibility can be easily realized.

  This embodiment will be described with reference to FIGS. Similar to the first embodiment, the light emitting diode package 1 is a blue light emitting package in which a resin is potted on a blue LED element. The difference from the first embodiment is that the reflective fluorescent film 5 color-converts the light of the light emitting diode package 1 at an early stage. By doing so, attenuation of the blue light guided in the light guide 3 can be prevented, and the luminance increases. Moreover, since the area of the reflective fluorescent film 5 can be significantly reduced, the cost reduction effect is also high.

  FIG. 8 is a cross-sectional view when the light emitting diode package 1 is disposed obliquely. The light source is disposed such that the light emitting surface thereof is inclined with respect to the bottom surface of the light guide, and the reflection sheet 14 is provided in parallel with the bottom surface of the light guide 3. The reflective fluorescent film 5 is installed so as to face the reflective surface of the reflective sheet 14. The light from the light source is reflected by the reflective sheet 14 and is directed to the reflective fluorescent film 5. According to such a configuration, the light from the light emitting diode package 1 is reflected by the reflection sheet 14 and further reflected in the direction parallel to the bottom surface of the light guide 3 while being color-converted by the reflective fluorescent film 5. A prism pattern and a diffusion pattern are disposed on the bottom surface of the light guide 3, and light is emitted from the surface opposite to the surface where the reflection sheet 14 is installed. The angle formed by the light output direction from the light emitting diode package 1 and the reflective sheet 14 (bottom surface of the light guide 3) is α, and the angle formed by the reflective fluorescent film 5 and the reflective sheet 14 (bottom surface of the light guide 3) is β. Then, when configured to satisfy the relationship of α = 2β, light from the light source can be efficiently converted and used as illumination light. In the present embodiment, only one reflective fluorescent film 5 is used. However, if a reflective fluorescent film is used instead of the reflective sheet 14, the color conversion density can be increased. For example, when a near-ultraviolet LED is used, it becomes possible to make visible light by using this reflective fluorescent film.

  As shown in the drawing, the light guide 3 is formed so that the light emitting surface and the light incident portion are parallel to each other at the light incident portion facing the light emitting surface of the light emitting diode package 1, and is opposed to the fluorescent reflection film 5. It is desirable to configure the portion to be parallel to the fluorescent reflection film. As a result, the light guide has a shape whose angle changes in two stages. Interface reflection can be reduced by sticking the fluorescent reflection film 5 and the reflection sheet 14 to the light guide 3 with an adhesive or the like. At this time, it may be configured such that the light from the light emitting diode package 1 is directly reflected by the reflection sheet 14 without being incident on the light guide 3 without providing a light incident portion in the light guide. Alternatively, after the light guide is not installed on the light path reflected from the light emitting diode package 1 by the reflective sheet 14 and further reflected by the fluorescent reflective film 5, the color conversion by the fluorescent reflective film 5 is completed in the air. You may comprise so that it may enter into a light guide.

  The configuration of the fluorescent reflection film 5 is the same as that of Example 1. The green fluorescent layer 9 and the red fluorescent layer 10 may be striped or matrix. There is also an adhesive layer for ensuring reliability, and the area of the adhesive layer can be used as a reflective area. If the adhesive layer is made longer and the light emitting diode package 1 or the like is covered, the leaked light can be efficiently reused. The frame 15 is the same as that of the first embodiment, and a material having high reflectance such as white pet or metal may be used.

  FIG. 9 is a cross-sectional view in the case where the light emitting diode package 1 is disposed so that the light emitting surface faces upward (light emitting direction of the light guide). Here, the reflective fluorescent film 5 is installed so as to be 45 ° with respect to the light emitting surface of the light emitting diode package 1. The angle of the reflective fluorescent film is ideally 45 degrees, but the color conversion function can be achieved even if it is about 30 degrees to 60 degrees. The light reflected and wavelength-converted by the reflective fluorescent film 5 is guided in the light guide 3, and is emitted from the three irradiation surfaces of the light guide by the diffusion pattern and the prism pattern installed on the bottom surface of the light guide 3. To do.

  FIG. 10 is a partial cross-sectional view showing an adapted configuration in which the present invention is applied to a so-called direct type illumination device mainly used for a large display. The reflective fluorescent film 5 is installed so as to be 45 ° with respect to the light emission direction of the light emitting diode package 1. A diffusion plate 16 is arranged perpendicular to the light reflected by the reflective fluorescent film 5. The diffuser plate 16 is generally distributed, and has a specification in which high refractive index transparent beads are dispersed in a transparent resin such as acrylic or polycarbonate. When the diffuser plate 16 is viewed from the front direction, a plurality of light emitting diodes 1 and the reflective fluorescent film 5 are arranged, and diffused and scattered by the diffuser plate 16 to form a surface emitting illumination device. If a liquid crystal panel is installed on top of this, a large screen and high image quality display device can be obtained. Further, the frame 15 is covered as in other cases, and the leaked light is reused.

It is a perspective view which shows typically the structure of the illuminating device by this invention. It is a perspective view which shows typically the structure of the fluorescence reflection film of the illuminating device of this invention. It is a front view which shows typically the structure of the fluorescence reflection film used in the Example. It is a front view which shows typically the structure of the fluorescence reflection film used in the Example. It is a front view which shows typically the structure of the fluorescence reflection film used in the Example. It is sectional drawing which shows typically the illuminating device by a prior art. It is sectional drawing which shows typically the illuminating device by an Example. It is sectional drawing which shows typically the illuminating device by an Example. It is sectional drawing which shows typically the illuminating device by an Example. It is sectional drawing which shows typically the illuminating device by an Example. It is a perspective view which shows typically the structure of the display apparatus by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light emitting diode package 2, 16 Diffusion film 3 Light guide 4 Circuit board 5 Fluorescent reflective film 6 Transparent moisture-proof film 7 Fluorescent layer 8 Reflective film 9 Green fluorescent layer 10 Red fluorescent layer 11 Adhesive layer 12 Fluorescent film 13 Phosphor 14 Reflective sheet 15 Frame 16 Diffuser 17 Liquid crystal panel

Claims (12)

In an illumination device in which light emitted from a light emitting element is surface-emitted using a light guide,
In the optical path between the light emitting element and the light exit surface of the light guide, a reflector for reflecting the light emitted from the light emitting element is provided, and the reflector has a wavelength conversion function for converting the wavelength of the light emitted from the light emitting element. A lighting device comprising:   The reflector has a first wavelength converter that converts the light emitted from the light emitting element into light having a first peak wavelength, and converts the light emitted from the light emitting element into light having a shorter wavelength than the first peak wavelength. The second wavelength converter is configured to exist independently of each other, and an area occupied by the second wavelength converter is smaller than an area of the first wavelength converter. The lighting device according to 1.   3. The illumination according to claim 2, wherein the first wavelength converter and the second wavelength converter are arranged in a stripe shape in the same direction as a main light output direction of light emitted from the light emitting element. apparatus.   The lighting device according to claim 2, wherein the first wavelength converter and the second wavelength converter are arranged in a dot matrix.   The said reflector is the structure by which the said wavelength converter was pinched | interposed between the reflective film which vapor-deposited the metal on the transparent film, and the moisture-proof film which gave the moisture-proof layer to the transparent film. The lighting device according to any one of the above.   The lighting device according to claim 5, wherein the reflective film and the moisture-proof film are bonded with an adhesive layer, and the adhesive layer is exposed on an end surface of the reflector.   The lighting device according to claim 6, wherein the adhesive layer is formed on an outer peripheral portion of the reflective film so that the wavelength converter is not exposed from an end face.   The reflection sheet is provided in an optical path between the light emitting element and the reflector, and the reflection sheet reflects light emitted from the light emitting element and guides it to the reflector. The lighting device according to one item.   The reflection sheet is disposed in parallel to the bottom surface of the light guide, and an angle formed between the light emitting direction from the light emitting element and the reflection sheet is α, and an angle formed between the reflector and the reflection sheet is β. The lighting device according to claim 8, wherein α = 2β is satisfied.   The light emitting element is arranged so that the direction of light emission coincides with the light output direction from the light guide, and the reflector is 30 degrees to 60 degrees with respect to the main light output direction of the light emitted from the light emitting element. The lighting device according to claim 1, wherein the lighting device is arranged at an angle.   The illumination device includes a diffusion plate on an irradiation surface side thereof, the light guide is formed of an air layer, and the reflector is provided so that light emitted from the light emitting element is perpendicularly incident on the diffusion plate. The illumination device according to any one of claims 1 to 7, wherein   A display device comprising: the illumination device having the configuration according to claim 1; and a non-self-luminous display element provided on an irradiation surface side of the illumination device.

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