JP2012209036A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device capable of outputting a luminous flux in high efficiency by enlarging the amount of luminous flux per unit area of a light-emitting section.SOLUTION: The light source device is provided with a first solid light-emitting element 2 to emit primary light; a first phosphor film 3 which absorbs the primary light and emits secondary light; a prism 1 which has an incident face 11 arranged along the first phosphor film 3 through the air, an inclined face 12 which faces inclined to the incident face 11, two perpendicular faces which are opposed to each other mutually in parallel perpendicular to the incident face 11 and the inclined face 12, an emitting face 13 which continues from the incident face 11, the inclined face 12, and the two perpendicular faces on the side where the interval between the incident face 11 and the inclined face 12 is widened, and has an area smaller than that of the first phosphor film, and an included angle face 14 which is opposed to the emitting face 13 in parallel; and a first secondary light reflecting film 4 which is arranged between the first solid light-emitting element 2 and the first phosphor film 3 and transmits the primary light and reflects the secondary light.

Description

  The present invention relates to a light source device used as a light source for a projection display device (projector) or the like.

  Conventionally, as a light source for a projector, a discharge lamp such as an ultra-high pressure mercury lamp, a xenon lamp, or a halogen lamp has been often used. Instead of such a discharge lamp, a semiconductor light source has been proposed for reasons such as low power consumption, instantaneous lighting, long life, high color purity and mercury-free. Among semiconductor light sources, light emitting diodes (LEDs) have spread rapidly in recent years, and household light bulbs are being replaced from conventional incandescent lamps to LEDs. On the other hand, as a light source for projectors, it has been used only as a light source for some low-intensity projectors. The reason is that since the LED is a surface emitting light source, it is necessary to increase both the input power and the area in order to increase the luminance. In other words, with the amount of light flux per unit area, the actual situation is that sufficient brightness to replace a conventional discharge lamp as a light source for a projector cannot be obtained.

  In view of this, it has been proposed to increase the efficiency of optical utilization of the LEDs that are lacking (see, for example, Patent Document 1). In Patent Document 1, a light beam emitted from an LED is reflected by a wedge-shaped prism and output from an emission surface having an area smaller than the area of the LED. This improves the etendue as a function of the light emitting area and the light radiation angle without increasing the amount of light flux per unit area of the light source and reducing the light radiation angle from the light source, and illuminates with high brightness can do.

JP 2008-26853 A

  However, in the system of Patent Document 1, the actual reflectance of the LED itself remains at about 70%, and there are many scattering components as well as regular reflection components. For this reason, it has been difficult to output the luminous flux emitted from the LED with high efficiency outside the system by repeatedly performing multiple reflection within the system including itself.

  In view of the above problems, an object of the present invention is to provide a light source device that can increase the amount of light flux per unit area of a light emitting unit and output the light flux with high efficiency.

  According to one aspect of the present invention, the first solid-state light emitting element (2, 2a, 31a) that emits primary light and the first phosphor film (3, 3a) that absorbs primary light and emits secondary light. ), An incident surface (11) arranged via air along the first phosphor film (3, 3a), an inclined surface (12) inclined to face the incident surface (11), and incident On the side where the distance between the two vertical surfaces (15, 16) perpendicular to the surface (11) and the inclined surface (12) and parallel to each other and the incident surface (11) and the inclined surface (12) increases, the incident surface ( 11) an emission surface (13) which is continuous with the inclined surface (12) and the two vertical surfaces (15, 16) and has an area smaller than the area of the first phosphor film (3, 3a); A prism (1) having an included angle surface (14) facing in parallel with (13), a first solid state light emitting device (2, 2a, 31a) and a first Provided with a first secondary light reflecting film (4, 4a) that is disposed between the fluorescent film (3, 3a) and transmits the primary light and reflects the secondary light. .

  In one aspect of the present invention, the length of the incident surface (11) is greater than the length (D1) of the first phosphor film (3) in the direction from the included angle surface (14) to the exit surface (13). The first phosphor film (3) is arranged so as to face a part of the incident surface (11) on the narrow-angle surface (14) side, and the exit surface (13) of the incident surface (11). You may further provide the metal film mirror (7) arrange | positioned so that the part which is not facing the 1st fluorescent substance film (3) of the side may be opposed via air.

  In one aspect of the present invention, the length of the incident surface (11) and the length of the first secondary light reflecting film (4) (D1 + D2) in the direction from the included angle surface (14) to the exit surface (13) Is longer than the length (D1) of the first phosphor film (3), and the first phosphor film (3) faces a part of the incident surface (11) on the narrow angle surface (14) side. It may be arranged as follows.

  In one aspect of the present invention, the apparatus further includes a second secondary light reflecting film (5) disposed along the inclined surface (12) through the air and transmitting the primary light and reflecting the secondary light. Also good. Or you may further provide the metal film mirror which is arrange | positioned through air along an inclined surface (12) and reflects primary light and secondary light.

  In one aspect of the present invention, a second phosphor film (3b) that is disposed via air along the inclined surface (12) and absorbs primary light and emits secondary light, and a second phosphor film (3b) is disposed between the second solid-state light emitting element (4b) that emits primary light for illuminating the second phosphor film (3b) and the second solid-state light emitting element (4b). You may further provide the 2nd secondary light reflection film (4b) which permeate | transmits primary light and reflects secondary light.

  1 aspect of this invention WHEREIN: It is arrange | positioned so that between 1st solid light emitting element (2) and 1st fluorescent substance films (3) may be enclosed, and the light pipe which has an inner wall surface which reflects primary light and secondary light (8) may be further provided.

  In one embodiment of the present invention, the light pipe (8) may have a tapered shape so as to spread from the first solid state light emitting device (2) side toward the first phosphor film (3) side. .

  1 aspect of this invention WHEREIN: You may further provide the primary light reflection film (6) which is arrange | positioned at the output surface (13) and reflects primary light and permeate | transmits secondary light.

  In one embodiment of the present invention, the first solid-state light emitting element (31b) may emit primary light having a single wavelength, and the spectral characteristics of the first secondary light reflecting film (4a) may be a narrow band. .

  ADVANTAGE OF THE INVENTION According to this invention, the light source device which can enlarge the light beam amount per unit area of a light emission part, and can output a light beam with high efficiency can be provided.

It is sectional drawing which shows an example of the light source device which concerns on the 1st Embodiment of this invention. It is a perspective view which shows an example of the prism which concerns on the 1st Embodiment of this invention. It is the schematic for demonstrating the illumination method which concerns on the 1st Embodiment of this invention. It is another schematic diagram for explaining the illumination method according to the first embodiment of the present invention. It is another schematic diagram for demonstrating the illumination method which concerns on the 1st Embodiment of this invention. It is another schematic diagram for demonstrating the illumination method which concerns on the 1st Embodiment of this invention. It is a graph showing the simulation result of the relationship between the light emission part area and brightness which concerns on the 1st Embodiment of this invention and a comparative example. It is a graph showing the spectral distribution of the primary light and the secondary light which concern on the 1st Embodiment of this invention. It is a graph showing the spectral characteristics of the primary light reflection film and secondary light reflection film which concern on the 1st Embodiment of this invention. It is sectional drawing which shows an example of the light source device which concerns on the modification of the 1st Embodiment of this invention. It is the schematic for demonstrating the illumination method which concerns on the modification of the 1st Embodiment of this invention. It is sectional drawing which shows an example of the light source device which concerns on the 2nd Embodiment of this invention. It is sectional drawing which shows an example of the light source device which concerns on the 3rd Embodiment of this invention. It is the schematic for demonstrating the illumination method which concerns on the 3rd Embodiment of this invention. It is a graph showing the angle characteristic of the secondary light reflection film which concerns on the 3rd Embodiment of this invention. It is another schematic diagram for demonstrating the illumination method which concerns on the 3rd Embodiment of this invention. It is sectional drawing which shows an example of the light source device which concerns on the 1st modification of the 3rd Embodiment of this invention. It is sectional drawing which shows an example of the light source device which concerns on the 2nd modification of the 3rd Embodiment of this invention. It is a graph showing the spectral distribution of the primary light and the secondary light which concern on the 2nd modification of the 3rd Embodiment of this invention. It is a graph showing the angle characteristic of the secondary light reflection film which concerns on the 2nd modification of the 3rd Embodiment of this invention. It is a perspective view which shows an example of the housing | casing which concerns on other embodiment of this invention.

  Next, first to third embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the relationship between the thickness and the planar dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Therefore, specific thicknesses and dimensions should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

  The first to third embodiments shown below exemplify apparatuses and methods for embodying the technical idea of the present invention, and the technical idea of the present invention is the component parts. The material, shape, structure, arrangement, etc. are not specified below. The technical idea of the present invention can be variously modified within the scope of the claims.

(First embodiment)
As shown in FIG. 1, the light source device according to the first embodiment of the present invention includes a solid-state light emitting element 2 that emits primary light (primary light source light), and absorbs primary light to secondary light (secondary light source). A phosphor film 3 that emits light), a wedge-shaped prism 1 that is disposed via the phosphor film 3 and air, a solid light-emitting element 2, and the phosphor film 3. A first secondary light reflection film 4 that transmits the primary light emitted by the fluorescent film 3 and reflects the secondary light emitted by the phosphor film 3.

  As a material of the prism 1, glass or resin having a refractive index larger than 1 can be used. Each surface of the prism 1 is a polished surface with a small surface roughness. The prism 1 can be manufactured by molding, in addition to polishing and cutting.

  As shown in FIGS. 1 and 2, the prism 1 faces a surface (hereinafter referred to as “incident surface”) 11 disposed along the phosphor film 3 via air and is inclined to the incident surface 11. A surface 12 (hereinafter referred to as an “inclined surface”), two surfaces (hereinafter referred to as “vertical surfaces”) 15 and 16 that are perpendicular to the incident surface 11 and the inclined surface 12 and are opposed to each other in parallel, and an incident surface. 11 and the inclined surface 12 on the side where the distance is widened, a surface that is continuous with the incident surface 11, the inclined surface 12, and the two vertical surfaces 15 and 16 and has an area smaller than the area of the phosphor film 3 (hereinafter referred to as “emission surface” ) 13 and a surface 14 (hereinafter, referred to as “an angled surface”) that faces the exit surface 13 in parallel.

  As the solid-state light-emitting element 2 shown in FIG. 1, various light-emitting elements such as LEDs and semiconductor lasers can be used. A reflective film is formed on the back surface side of the solid state light emitting device 2, and primary light emitted from the light emitting layer is reflected directly or by the reflective film and emitted to the front surface side. The solid light emitting element 2 has a rectangular shape of, for example, about 2 mm × 6 mm when viewed from above. In the first embodiment of the present invention, a blue LED is used as the solid state light emitting device 2. The solid state light emitting device 2 is supported by a support member 21 having a reflective surface that reflects primary light.

The phosphor film 3 is formed by coating on a substrate 23 such as glass so as to face a part of the incident surface 11 on the narrow angle surface 14 side. The shape of the phosphor film 3 in a top view is substantially the same as that of the solid light emitting element 2, and the area of the phosphor film 3 is equal to the area of the solid light emitting element 2. As the material of the phosphor film 3, various phosphors such as sulfide, oxide or nitride can be employed. The phosphor film 3 behaves as a secondary light source, absorbs primary light emitted by the solid state light emitting device 2 as excitation light, and emits secondary light having a wavelength different from that of the primary light. For example, when the primary light is blue light, the phosphor film 3 emits ultraviolet to visible light such as green or red. In the direction parallel to the incident surface 11 from the sandwiched surface 14 to the exit surface 13, the length (D1 + D2) of the substrate 23 is longer than the length D1 of the phosphor film 3, and the length of the incident surface 11 is the substrate. It is longer than the length of 23 (D1 + D2). The first secondary light reflecting film 4 is disposed on the surface of the substrate 23 opposite to the surface on which the phosphor film 3 is disposed so as to have substantially the same area as the phosphor film 3. As the first secondary light reflecting film 4, for example, a dichroic film in which thin films made of silicon oxide (SiO ₂ ) and titanium oxide (TiO ₂ ) having different refractive indexes are alternately stacked can be used. The first secondary light reflecting film 4 can be formed on the substrate 23 by vapor deposition or the like.

  Further, a metal film mirror 7 such as a silver mirror that reflects all visible light with high reflectivity (for example, 98% or more) is disposed in a portion where the first secondary light reflection film 4 on the substrate 23 is not disposed. Has been. The metal film mirror 7 is disposed so as to face a portion of the incident surface 11 that is not opposed to the phosphor film 3 on the exit surface 13 side via air.

Furthermore, the second secondary light reflecting film 5 is disposed along the inclined surface 12 via air. The second secondary light reflecting film 5 is disposed on a substrate 24 such as glass. The length D3 of the second secondary light reflecting film 5 and the substrate 24 is substantially the same as the length (D1 + D2) of the substrate 23 in the direction parallel to the inclined surface 12 from the sandwiched surface 14 to the exit surface 13. . The second secondary light reflecting film 5 transmits the primary light and reflects the secondary light. As the second secondary light reflecting film 5, for example, a dichroic film in which thin films made of silicon oxide (SiO ₂ ) and titanium oxide (TiO ₂ ) having different refractive indexes are alternately stacked can be used. The second secondary light reflecting film 5 can be formed on the substrate 24 by vapor deposition or the like.

Further, the primary light reflecting film 6 is disposed on the emission surface 13. The primary light reflecting film 6 reflects the primary light and transmits the secondary light. As the primary light reflecting film 6, for example, a dichroic film in which thin films made of silicon oxide (SiO ₂ ) and titanium oxide (TiO ₂ ) having different refractive indexes are alternately stacked can be used. The primary light reflection film 6 can be formed on the emission surface 13 by vapor deposition or the like.

  Further, a quadrangular cylinder (light pipe) 8 is disposed so as to surround the solid light emitting element 2 and the phosphor film 3. The light pipe 8 has an inner wall surface formed of a mirror that reflects primary light and secondary light. A cover member 22 is disposed outside the light pipe 8 so as to surround the light pipe 8.

  Next, an illumination method using the light source device according to the first embodiment of the present invention (principle of light output) will be described with reference to FIGS. 3 to 6, the primary light is indicated by a dotted arrow, and the secondary light is indicated by a solid arrow.

  As shown in FIG. 3, the primary light (blue light) emitted from the solid state light emitting device 2 passes through the first secondary light reflecting film 4 and the substrate 23 through the light pipe 8 and illuminates the phosphor film 3. To do. As shown in FIGS. 3 and 4, the phosphor film 3 absorbs primary light as excitation light and emits secondary light (green light). At that time, each phosphor particle in the phosphor film 3 individually absorbs the primary light and emits the secondary light in all directions (360 degrees). Therefore, about half of the primary light is emitted to the prism 1 side. On the other hand, the remaining light is emitted to the opposite side, but is reflected by the first secondary light reflecting film 4 and all the secondary light is directed to the prism 1 side. Further, a part of the primary light is transmitted through the phosphor film 3 without being absorbed by the phosphor film 3.

  As shown in FIG. 5, the secondary light emitted from the phosphor film 3 and a part of the primary light transmitted through the phosphor film 3 enter the incident surface 11 of the prism 1 through the air, Multiple reflection at. Since each surface of the prism 1 is mirror-polished, from the prism 1 having a high refractive index to the outside of the low system, all light rays exceeding the angle satisfying Snell's law are internally reflected within the prism 1 exceeding the critical angle Wake up. Accordingly, all the primary light and secondary light incident from the phosphor film 3 are internally reflected on the two vertical surfaces 15 and 16 and the included angle surface 14.

  On the other hand, at the incident surface 11 and the inclined surface 12, some rays do not exceed the critical angle when entering the prism 1, so that they exit the prism 1 system. The emitted light beam is reflected by the first secondary light reflection film 4, the second secondary light reflection film 5, and the metal film mirror 7 and returned to the prism 1 again. Since the prism 1 has a wedge shape so as to spread toward the exit surface 13 side, light rays that do not exceed the critical angle exceed the critical angle by being subjected to multiple reflection and are internally reflected. The incident surface 11, the exit surface 12, and the two of the prism 1 with respect to the length D 1 of the phosphor film 3 shown in FIG. The vertical surfaces 15 and 16 are lengthened, and the length D2 of the metal film mirror 7 and the length D3 of the second secondary light reflecting film 5 are appropriately lengthened. In this way, light is emitted out of the system with high efficiency from the exit surface 13 by repeating multiple reflections in the prism 1.

  In addition, as shown in FIG. 6, when the secondary light is emitted from the incident surface 11 to the outside of the prism and is incident on the first secondary light reflecting film 4, the difference in refractive index between glass and air is the glass and fluorescence. Since the difference in refractive index of the body film 3 is large, the incident angle of the secondary light incident on the first secondary light reflecting film 4 is small. Therefore, the secondary light reflecting film 4 can reflect the secondary light with high probability.

  As described above, according to the light source device according to the first embodiment of the present invention, the area of the phosphor film 3 that emits the secondary light is larger than the area of the emission surface 13 that emits the secondary light. Therefore, etendue can be improved and illumination can be performed with high brightness. Then, the phosphor film 3 emits secondary light with the primary light from the solid state light emitting device 2, and the secondary light is reflected by the first secondary light reflecting film 4, whereby the incident surface 11 and the inclined surfaces 12 are aligned with each other. Thus, the secondary light repeats multiple reflections, and the secondary light can be efficiently output from the exit surface 13. Therefore, the amount of light flux per unit area can be increased, and the light flux can be output with high efficiency.

  FIG. 7 shows a simulation result of the relationship between the area of the phosphor film 3 and the brightness. Although the details differ depending on the area of the phosphor film 3 and the angle of the wedge formed by the incident surface 11 and the inclined surface 12 of the prism 1, light emitted from the LED as a comparative example is incident on the prism as it is, and multiple reflection is repeated. The light source device according to the first embodiment of the present invention may be nearly twice as bright as the emitted configuration. In particular, increasing the area of the phosphor film 3 has the effect, and since it exceeds the limit that would not have been achieved even if the LED was increased in size, higher brightness can be expected.

  Furthermore, according to the light source device according to the first embodiment of the present invention, the secondary light reflected from the inclined surface 12 is returned into the prism 1 by arranging the second secondary light reflecting film 5. Can do.

  Incidentally, the primary light and the secondary light have spectral characteristics as shown in FIG. As described above, in addition to the secondary light, the primary light is partially mixed in the light beam incident on the prism 1 from the phosphor film 3. This relates to the luminous efficiency of the phosphor film 3 and is a component that is transmitted as it is without being absorbed by the phosphor film 3. If this component is mixed in the emitted light, a desired spectrum cannot be obtained and the pure color is deteriorated. As shown in FIG. 9, the first secondary light reflection film 4, the second secondary light reflection film 5, and the primary light reflection film 6 have high reflection of 98% or more in each band. Therefore, by arranging the second secondary light reflecting film 5, the blue light component of the light rays not exceeding the critical angle can be transmitted outside the system through the second secondary light reflecting film 5. .

  Furthermore, according to the light source device according to the first embodiment of the present invention, the primary light reflecting film 6 is arranged on the emission surface 13 so that the primary light transmitted without being absorbed by the phosphor film 3 is emitted. It can be returned to the prism 1 without being output from the surface 13. The primary light excites the phosphor film 3 again to emit light, so that the secondary light can be further amplified and the amount of light flux per unit area can be increased.

  Furthermore, the solid light emitting element 2 and the prism 1 are spaced apart from each other due to physical factors such as an electrode disposed on the surface of the solid light emitting element 2 and a wire bonding loop for supplying power to the electrode. According to the light source device according to the first embodiment of the present invention, it is possible to prevent leakage of light flux from the gap between the solid light emitting element 2 and the prism 1 by having the light pipe 8.

<Modification>
As a modification of the first embodiment of the present invention, as shown in FIG. 10, the first secondary light reflection film 4 may be disposed between the substrate 23 and the phosphor film 3. Further, the first secondary light reflecting film 4 may cover the entire surface of the substrate 23. The length (D1 + D2) of the first secondary light reflecting film 4 is longer than the length D1 of the phosphor film 3.

  In the modification of the first embodiment of the present invention, as shown in FIG. 11, the secondary light emitted from the phosphor film 3 toward the substrate 23 is reflected by the first secondary light reflecting film 4 immediately below. , All secondary light travels toward the prism 1 side. The secondary light emitted from the prism 1 through the incident surface 11 is reflected by the first secondary light reflecting film 4 and returned to the prism 1.

(Second Embodiment)
In the first embodiment of the present invention, the case of having one set of light sources of the solid state light emitting element 2 and the phosphor film 3 has been described. However, in the second embodiment of the present invention, two sets of light sources are provided. Explain the case.

  As shown in FIG. 12, the light source device according to the second embodiment of the present invention is disposed on the incident surface 11 side of the prism 1 along the incident surface 11 via air, and absorbs primary light. A first phosphor film 3a emitting secondary light, a first solid-state light emitting element 2a emitting primary light for illuminating the first phosphor film 3a, the first phosphor film 3a and the first phosphor film 3a. The first secondary light reflecting film 4a is disposed between the first and second solid state light emitting devices 2a and transmits primary light and reflects secondary light.

  The first solid state light emitting device 2a is supported by a support member 21a. A light pipe 8a and a cover member 22a are disposed between the first solid state light emitting device 2a and the first phosphor film 3a.

  The first phosphor film 3a and the first secondary light reflecting film 4a are disposed on the substrate 23a. A metal film mirror 7a such as a silver mirror that reflects all visible light with high reflectivity (for example, 98% or more) is disposed in a portion of the substrate 23a where the first phosphor film 3a is not disposed.

  Furthermore, the light source device according to the second embodiment of the present invention is disposed on the inclined surface 12 side of the prism 1 via air along the inclined surface 12, and absorbs primary light and emits secondary light. Second phosphor film 3b, second solid-state light emitting element 2b that emits primary light for illuminating second phosphor film 3b, second phosphor film 3b, and second solid-state light emitting element 2b And a second secondary light reflecting film 4b that transmits the primary light and reflects the secondary light.

  The second solid state light emitting device 2b is supported by a support member 21b. A light pipe 8b and a cover member 22b are disposed between the second solid state light emitting device 2b and the second phosphor film 3b.

  The second phosphor film 3b and the second secondary light reflecting film 4b are disposed on the substrate 23b. A metal film mirror 7b such as a silver mirror that reflects all visible light with high reflectivity (for example, 98% or more) is disposed in a portion of the substrate 23b where the second phosphor film 3b is not disposed.

  Other configurations are substantially the same as those of the first embodiment of the present invention, and a duplicate description is omitted.

  Next, an example of an illumination method using the light source device according to the second embodiment of the present invention will be described with reference to FIG.

  The primary light emitted from the first solid state light emitting device 2a passes through the first secondary light reflecting film 4a and the substrate 23a through the light pipe 8a, and illuminates the first phosphor film 3a. The first phosphor film 3a absorbs the primary light and emits secondary light. On the other hand, the primary light emitted from the second solid state light emitting element 2b passes through the second secondary light reflecting film 4b and the substrate 23b through the light pipe 8b, and illuminates the second phosphor film 3b. The second phosphor film 3b absorbs the primary light and emits secondary light.

  The secondary light from each of the first phosphor film 3a and the second phosphor film 3b is the secondary light reflected by the first secondary light reflection film 4a and the second secondary light reflection film 4b, and Along with the afterglow component of the primary light, it enters the prism 1 through the air, and the first secondary light reflecting film 4a, the second secondary light reflecting film 4b, the metal film mirror 7a, in the prism 1 and in the vicinity of the prism 1, Multiple reflection is repeated at 7 b and output from the exit surface 13.

  At this time, some secondary lights emitted from the first phosphor film 3a and the second phosphor film 3b are respectively transmitted to the first phosphor film 3a and the second phosphor film 3b on the opposite surfaces. Incident. The first phosphor film 3a and the second phosphor film 3b exhibit an absorption characteristic with respect to the primary light, but do not have an absorption characteristic with respect to the secondary light. The phosphor film 3a and the second phosphor film 3b are respectively transmitted or partially scattered, reflected by the first secondary light reflecting film 4a and the second secondary light reflecting film 4b, and again the first phosphor. The light passes through the film 3 a and the second phosphor film 3 b and reenters the prism 1. On the other hand, a part of the residual component of the primary light is similarly incident on the first phosphor film 3a and the second phosphor film 3b on the opposite surfaces, but the first phosphor film 3a and the second phosphor. The film 3b absorbs and contributes to the emission of secondary light.

  Further, a part of the primary light is reflected by the primary light reflecting film 6 on the exit surface 13 and returned to the system again. Since the primary light has a completely closed system, multiple reflection is repeated again, and the light is incident again on the first phosphor film 3a and the second phosphor film 3b and contributes to light emission. The primary light transmitted again through the first phosphor film 3a and the second phosphor film 3b is transmitted through the first secondary light reflection film 4a and the second secondary light reflection film 4b and the substrates 23a and 23b. Then, the light returns to the first solid state light emitting device 2a and the second solid state light emitting device 2b via the light pipes 8a and 8b. This light beam is reflected by the first solid-state light-emitting element 2a and the second solid-state light-emitting element 2b itself, and illuminates the first phosphor film 3a and the second phosphor film 3b again. As described above, all the primary light including the residual component is absorbed by the first phosphor film 3a and the second phosphor film 3b and contributes to the emission of the secondary light.

  As described above, according to the light source device according to the second embodiment of the present invention, even in a system in which a plurality of light sources are combined, the amount of light flux per unit area is large and illumination can be performed with high efficiency. It becomes.

(Third embodiment)
As shown in FIG. 13, the light source device according to the third embodiment of the present invention has a tapered shape so that the light pipe 8 spreads from the solid light emitting element 2 side toward the phosphor film 3 side. Different from the first embodiment of the present invention. The areas of the phosphor film 3 and the first secondary light reflection film 4 are larger than the area of the solid state light emitting device 2. Other configurations are substantially the same as those of the first embodiment of the present invention, and a duplicate description is omitted.

  Next, an example of an illumination method using the light source device according to the embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 14, the primary light emitted from the solid state light emitting device 2 has an angle θ0 with respect to the normal direction of the surface of the solid state light emitting device 2, and the light exit surface 13 while being reflected multiple times within the light pipe 8. Head to. At this time, since the reflecting surface in the light pipe 8 is inclined, the angles θ0, θ1, and θ2 toward the phosphor film 3 are reduced every time the primary light is reflected. Accordingly, any primary light emitted from the light pipe 8 becomes substantially parallel light. The primary light emitted from the light pipe 8 passes through the substrate 23, passes through the first secondary light reflecting film 4, and illuminates the phosphor film 3.

  Here, as shown in FIG. 15, in the angle characteristics of the dichroic mirror constituting the first secondary light reflecting film 4, when the angle of the incident light beam increases, the spectral reflection characteristics shift to the short wavelength side. Therefore, even if it is primary light, a component having a large light beam angle cannot be transmitted, and a phenomenon in which the phosphor film 3 cannot be sufficiently illuminated with primary light may occur, and a desired high brightness may not be obtained. On the other hand, according to the third embodiment of the present invention, since the light pipe 8 has a tapered shape, the primary light can be made substantially parallel light. The phosphor film 3 can be illuminated with high efficiency without being reflected by the angle characteristic of 4.

  The illuminated phosphor film 3 absorbs primary light and emits secondary light (green light). At that time, each phosphor particle inside the phosphor film 3 individually absorbs blue light and emits green light in all directions (360 degrees). Therefore, about half of the primary light is emitted to the prism 1 side, while the remaining light is emitted to the opposite substrate 23 side. This time, a light beam with a considerable angle is incident on the first secondary light reflection film 4, but the reflection band of the secondary light is widened by the angle characteristics of the first secondary light reflection film 4, so that almost all Light can be reflected and directed to the prism 1 side. Then, as shown in FIG. 16, the secondary light emitted from the phosphor film 3 is subjected to multiple reflection by the prism 1, the first secondary light reflecting film 4, the second secondary reflecting film 5, and the metal film mirror 7. Is repeated and ejected from the exit surface 13. At this time, since the light pipe 8 has a tapered shape, it becomes easier to return the light beam incident on the light pipe 8 to the prism 1 as compared with the case where the diameter of the light pipe 8 is constant.

  As described above, according to the light source device according to the third embodiment of the present invention, by providing the tapered light pipe 8, the phosphor film 3 can be illuminated with high efficiency, and the phosphor film 3 emits light. By increasing the brightness, it is possible to increase the amount of light flux per unit area of the emitted light flux. Further, when the primary light that has been multiple-reflected in the prism 1 and returned to the phosphor film 3 is incident at a predetermined incident angle or more, the light is again transmitted without passing through the first secondary light reflecting film 4. It can be returned to the phosphor film 3. Therefore, the phosphor film 3 can be illuminated with primary light with high efficiency.

<First Modification>
As a first modified example of the third embodiment of the present invention, as shown in FIG. 17, two sets of light sources are provided, and each of the light pipes 8a and 8b includes the first solid-state light emitting element 2a and the first The second solid-state light emitting element 2b may have a tapered shape toward the first phosphor film 3a and the second phosphor film 3b. Other configurations are substantially the same as those of the light source device according to the second embodiment of the present invention shown in FIG.

<Second Modification>
As a second modification of the third embodiment of the present invention, as shown in FIG. 18, lasers 31a and 31b that output a single wavelength may be used instead of LEDs. The lasers 31a and 31b are arranged outside the system. Although FIG. 18 shows a laser array in which a plurality of lasers 31a and 31b are used, the number of lasers 31a and 31b may be one and the number is not particularly limited. The lasers 31a and 31b emit a blue laser having a single wavelength as shown in FIG. Light rays output from the lasers 31a and 31b are emitted radially, and are collimated by collimating lenses 32a and 32b. Thereafter, the plurality of parallel lights are incident on the end faces of the light pipes 8a and 8b through the common condenser lenses 33a and 33b. The light rays that are multiply reflected in the light pipes 8a and 8b illuminate the first phosphor film 3a and the second phosphor film 3b as substantially parallel light, respectively. The other configuration is substantially the same as the configuration shown in FIG.

  When a single wavelength is output as in the blue laser shown in FIG. 19, as shown in FIG. 20, the phosphor film 3 is used as the first secondary light reflecting film 4a and the second secondary light reflecting film 4b. By using a reflective film with a narrow band that transmits the substantially parallel light that illuminates and reflects the return light that returns by multiple reflection within the prism 1, the primary light is confined in the system, and all the primary light is reflected. Light can be contributed to light emission in the phosphor film 3.

(Other embodiments)
As described above, the present invention has been described according to the first to third embodiments. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments, examples and operational techniques will be apparent to those skilled in the art.

  For example, instead of the second secondary light reflecting film 5 shown in FIG. 1, a metal film mirror such as a silver mirror that reflects all visible light with high reflectivity (for example, 98% or more) may be provided. By arranging the metal film mirror, the primary light transmitted without being absorbed by the phosphor film 3 is returned into the prism 1, and the phosphor film 3 is excited again to emit light, thereby further amplifying the secondary light. The amount of light flux per unit area can be increased.

  Further, in the first to third embodiments of the present invention, the wedge-shaped prism 1 has been described. Instead of the prism 1, a wedge-shaped housing 1x filled with air as shown in FIG. You may do it. In this case, a metal film mirror that reflects primary light and secondary light or a secondary light reflecting film that reflects secondary light is formed on the inner wall surface of the housing 1x. Furthermore, it is only necessary to provide an opening 17 for entering the secondary light from the phosphor film 3 and an opening 18 larger than the area of the opening 17 for emitting the secondary light.

  In addition, the prism 1 according to the first to third embodiments of the present invention may have a configuration in which the incident surface 11 and the inclined surface 12 are significantly larger than the exit surface 13. Further, the phosphor film 3 may have a significantly larger area than the exit surface 13 of the prism 1. The present invention is also applicable to a wedge shape in which the prism 1 has no included angle surface 14 and the incident surface 11 and the inclined surface 12 are continuous. The vertical surfaces 15 and 16 are preferably perpendicular to the incident surface 11 and the inclined surface 12 and parallel to each other, but may not be strictly vertical and parallel. Furthermore, the exit surface 13 and the included angle surface 14 are preferably parallel to each other, but may not be strictly parallel.

  In the first to third embodiments of the present invention, the case where blue light is emitted as the primary light and green light is emitted as the secondary light has been described. However, the secondary light is excited by the blue light of the primary light as shown in FIG. It is also possible to emit red light having a wavelength band as shown in FIG. Furthermore, a desired spectrum in the visible light region may be emitted using ultraviolet light having a short wavelength (high energy) as excitation light. In that case, as the secondary light reflecting films 4, 5, 4a, and 4b, films that reflect and transmit the spectrum of each band can be appropriately selected.

  In addition, the light source device according to the first to third embodiments of the present invention forms a spatial light modulation element that modulates the secondary light emitted from the light source device and an image of the modulated secondary light. The present invention is also applicable to an image display apparatus having an imaging optical system that displays on a screen or the like.

  As described above, the present invention naturally includes various embodiments not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

DESCRIPTION OF SYMBOLS 1 ... Prism 1x ... Case 2, 2a, 2b ... Solid light emitting element 3, 3a, 3b ... Phosphor film 4, 4a, 4b, 5 ... Secondary light reflecting film 6 ... Primary light reflecting film 7, 7a, 7b ... Metal film mirror 8, 8a, 8b ... Light pipe 11 ... Incident surface 12 ... Inclined surface 13 ... Ejection surface 14 ... Nangling surface 15, 16 ... Vertical surface 17, 18 ... Opening 21, 21, 21a, 21b ... Support member 22, 22a, 22b ... Cover member 23, 23a, 23b, 24 ... Substrate 31a, 31b ... Laser 32a, 32b ... Collimating lens 33a, 33b ... Condensing lens

Claims (10)

A first solid state light emitting device emitting primary light;
A first phosphor film that absorbs the primary light and emits secondary light;
An incident surface disposed via air along the first phosphor film, an inclined surface that is inclined and opposed to the incident surface, and 2 that are perpendicular to the incident surface and the inclined surface and are parallel to each other. Two vertical surfaces, and a side where the interval between the incident surface and the inclined surface is widened, and is continuous with the incident surface, the inclined surface, and the two vertical surfaces, and has an area smaller than the area of the first phosphor film. A prism having an exit surface and a narrow angle surface facing in parallel with the exit surface;
A first secondary light reflecting film disposed between the first solid-state light emitting element and the first phosphor film and transmitting the primary light and reflecting the secondary light. A light source device. In the direction from the sandwiched surface to the exit surface, the length of the entrance surface is longer than the length of the first phosphor film,
The first phosphor film is disposed so as to face a part of the incident surface on the narrow surface side;
The metal film mirror further arranged so that it may oppose via the air with the part which is not facing the said 1st fluorescent substance film of the said output surface side of the said incident surface. Light source device. In the direction from the sandwiched surface to the exit surface, the lengths of the entrance surface and the first secondary light reflection film are longer than the length of the first phosphor film,
The light source device according to claim 1, wherein the first phosphor film is disposed so as to face a part of the incident surface on the narrow-angle surface side.   4. The apparatus according to claim 1, further comprising a second secondary light reflecting film that is disposed along the inclined surface through the air and transmits the primary light and reflects the secondary light. The light source device according to claim 1.   4. The light source device according to claim 1, further comprising a metal film mirror that is disposed along the inclined surface via air and reflects the primary light and the secondary light. 5. . A second phosphor film disposed along the inclined surface via air, absorbing the primary light and emitting secondary light;
A second solid-state light emitting element that emits the primary light for illuminating the second phosphor film;
A second secondary light reflecting film that is disposed between the second phosphor film and the second solid state light emitting element and transmits the primary light and reflects the secondary light. The light source device according to claim 1, wherein the light source device is a light source device.   The light pipe having an inner wall surface that is disposed so as to surround between the first solid state light emitting device and the first phosphor film and reflects the primary light and the secondary light. Item 7. The light source device according to any one of Items 1 to 6.   The light source device according to claim 7, wherein the light pipe has a tapered shape so as to spread from the first solid state light emitting element side toward the first phosphor film side.   The light source device according to claim 1, further comprising a primary light reflecting film that is disposed on the emission surface and reflects the primary light and transmits the secondary light. The first solid state light emitting device emits the primary light having a single wavelength;
The light source device according to claim 1, wherein spectral characteristics of the first secondary light reflection film are in a narrow band.

Images