JP2008041288A - Light source module and projection type display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source module having excellent utilization efficiency of light, and improved to reduce size, thickness and weight with a simple structure and a projection type display apparatus. <P>SOLUTION: The light source module includes a light source and an optical element to which the light from the light source incomes. The optical element of the light source module includes a combination portion combined with the light source, a predetermined light-outgoing portion formed in a surface except for the surface having the combination portion, and a reflective portion having a reflective film or a reflection structure for reflecting the light from the light source formed therein. Thus, an etendue of the light source is converted, a microstructure is easily formed on a secondary light source surface, and directivity and polarization characteristics are easily controlled, utilization efficiency of light is excellent, and size, thickness and weight are reduced with a simple structure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light source module and a projection display device, and more particularly to a configuration of a small, light, and thin projection display device.

  2. Description of the Related Art Conventionally, there is known a projection display device that synthesizes image light using a light modulation device such as a liquid crystal light valve and enlarges and projects the synthesized image light onto a screen through a projection optical system including a projection lens. Hereinafter, the configuration of a conventional projection display device will be described with reference to the drawings.

FIG. 20 is a schematic configuration diagram showing a configuration of a conventional projection display device. In the figure, a conventional projection display apparatus 100 includes a light source 101, dichroic mirrors 102 and 103, reflection mirrors 104 to 106, liquid crystal light valves 107 to 109, a cross dichroic prism 110, and a projection lens 111. It consists of The light source 101 includes a lamp 112 such as a metal halide and a reflector 113 that reflects light from the lamp 112. The dichroic mirror 102 the blue light, green light reflecting transmits a red light L _R of the light beam from the light source 101 and reflects the blue light L _B and the green light L _G. The transmitted red light L _R is reflected by the reflection mirror 104 and enters the red light liquid crystal light valve 107. Meanwhile, among the color light reflected by the dichroic mirror 102, the green light L _G reflected by the dichroic mirror 103 for reflecting green light, and enters the green light liquid crystal light valve 108. On the other hand, the blue light L _B also passes through the dichroic mirror 103 and enters the liquid crystal light valve 109 for blue light through the reflection mirrors 105 and 106.

  Thus, the three color lights modulated by the liquid crystal light valves 107, 108 and 109 are incident on the cross dichroic prism 110. In this prism, four right-angle prisms are bonded, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in a cross shape on the inner surface. These dielectric multilayer films combine the three color lights to form light representing a color image. The synthesized light is projected onto the projection screen 114 by the projection lens 111, which is a projection optical system, and an enlarged image is displayed.

As described above, in a conventional projection display device, light emitted from a light source is separated into three color lights using a dichroic mirror, and each separated color light is modulated using three liquid crystal light valves. After that, the composition is again synthesized by the dichroic prism and is projected onto the screen by the projection lens. Therefore, a large number of optical components are required, and it has been fundamentally difficult to reduce the size, weight, and thickness of the apparatus. In order to solve this problem, for example, Patent Document 1 discloses a plurality of light emitting diodes (hereinafter, abbreviated as red, green, and blue (hereinafter abbreviated as red, green as G, and blue as B)). An LED array in which light emitting diodes (hereinafter abbreviated as LEDs) are arranged in a planar or curved surface, and a plurality of rod lenses for equalizing the illuminance of each color light emitted from each LED are planar or curved. Rod lens array arranged in a line, a PBS array that performs polarization conversion of light emitted from the rod lens array, a liquid crystal light valve that synthesizes an image by modulating each color light emitted from the PBS array, and a liquid crystal light There has been proposed a projection display device that includes a projection lens that magnifies and projects an image synthesized by a valve onto a screen. Further, Patent Document 2 includes an LED array including a reflection plate on the rear side with respect to the light emitting direction, a phase difference plate, a taper rod lens array, a rod lens array, and a reflective polarizing plate. A thin illumination device that performs polarization conversion has been proposed.
JP 2003-295315 A JP 2003-329978 A

  However, in Patent Document 1, since the illuminance is uniformed by the rod lens for each color light, at the rod lens emitting end face, the single lens emitted from one or a plurality of LED chips passing through the rod lens is used. Although the illuminance is uniformized for one color light, a plurality of color lights (for example, R, G, B, respectively) are not necessarily uniform on the light valve after emission from the rod lens. Further, in order to further reduce the size of the device, it is necessary to make the LED itself smaller, but at present, the limit is about 300 μm per chip, and the size of the rod lens is also limited thereby. Further, when the number of LED chips to be used increases, there are problems that the number of wires increases and the LEDs cannot be laid out within a predetermined area, and there are problems in controlling a plurality of LED chips whose characteristic values are slightly different within the specification range.

  Moreover, in the said patent document 2, as a reflective polarizing plate, the grid polarizer and film in which many ribs which consist of metals which have light reflectivity, such as aluminum, were formed on the glass substrate with the pitch smaller than the wavelength of incident light. A so-called reflective polarizing plate element such as a multilayer laminated polarizing plate is required, which is an adverse effect of thinning.

  The present invention is intended to solve these problems, and provides a light source module and a projection display device that are excellent in light use efficiency and can be reduced in size, thickness, and weight with a simple configuration. Objective.

  In order to solve the above problems, the light source module of the present invention includes a light source and an optical element on which light from the light source is incident. The optical element in the light source module of the present invention includes a coupling portion coupled to the light source, a predetermined light emitting portion formed on a surface other than the surface having the coupling portion, and a reflective film that reflects light from the light source or It has a feature in that it has a reflecting portion formed with a reflecting structure. Therefore, the etendue of the light source can be converted, it is easy to form a fine structure on the surface of the secondary light source, the directivity and polarization characteristics can be easily controlled, the light utilization efficiency is excellent, and the size is reduced with a simple configuration. Further, the thickness and weight can be reduced.

  The optical element is formed of a light scattering optical member including a light scattering body or light scattering particles. Therefore, it is possible to simplify the shape of the optical element by making the light density in the optical element uniform, and to reduce the size of the optical element by having high scattering characteristics, thereby reducing the size of the optical module. .

  Furthermore, the light source module of the present invention includes a light source, a first optical element that receives light from the light source, and a second optical element that receives light emitted from the first optical element. Have. The first optical element in the light source module of the present invention includes a first coupling unit coupled to the light source, a second coupling unit coupled to the second optical element, and a reflective film that reflects light from the light source. Alternatively, the second optical element has a reflection part on which a reflection structure is formed, and the second optical element has a first surface having an area equal to or greater than the area of the coupling part coupled to the first optical element, and the first surface. And a second surface that is larger than the first surface and faces the first surface. Therefore, a secondary light source can be formed and the etendue of the light source can be converted, and the directivity of light emitted from the secondary light source can be improved by the second optical element, and the illuminance on the light valve can be made uniform. It is possible to provide an optical module that is excellent in light utilization efficiency and can be reduced in size, thickness, and weight with a simple configuration.

  Further, there are a plurality of coupling portions that couple the first optical element and the second optical element, and the second optical element is a rod in which a columnar rod having a first surface and a second surface as a bottom surface is two-dimensionally arranged. By using the array, the second optical element necessary for uniform illumination and improved directivity on the light valve can be reduced in size.

  Further, a reflection film or a reflection structure that reflects light from the light source is formed on the side surface of the rod that is a surface connecting the first surface and the second surface of the second optical element, so that the angle can be reduced. The light incident on the side surface of the rod can be kept in the rod, and the light use efficiency can be improved.

  The first optical element in the optical module of the present invention includes a first coupling portion coupled to the light source, a second coupling portion coupled to the second optical element, and a reflective film that reflects light from the light source. Alternatively, the second optical element has a first opening surface and a larger area than the first opening surface and is opposed to the first opening surface. The hollow rod has two opening surfaces and the first and second opening surfaces are the bottom surfaces. A reflection film or a reflection structure for reflecting light from the light source is formed on the side surface of the hollow rod. Further, a reflection film or a reflection structure for reflecting light from the light source is formed on the surface where the first optical element and the second optical element are in contact with each other. Therefore, it becomes easy to make an opening to be a secondary light source, making it easy to make a module, and making a hollow rod makes it easy to make a mold. In addition, the second optical element can be made of a metal other than a transparent member such as glass or resin, so that the selectivity of the material can be expanded.

  In addition, the hollow rod array in which the hollow rods of the second optical element are two-dimensionally arranged makes it possible to reduce the size of the second optical element necessary for uniform illumination and improved directivity on the light valve. it can.

  In addition, the first optical element is formed of a light scattering optical member including a light scatterer or a light scattering particle, so that the light density in the first optical element is made uniform, thereby making the first optical element uniform. The optical module can be miniaturized because the first optical element itself can be miniaturized by simplifying the shape and having high scattering characteristics.

  Furthermore, since the light source is a light source composed of a light emitting device that includes at least three colors of red, green, and blue, a full color can be supported.

  The space between the first optical element and the second optical element is transparent to the light from the light source and is filled or bonded with a member having a higher refractive index than air. Therefore, it is possible to improve the light extraction efficiency from the secondary light source by eliminating the interface between the secondary light source and air formed on the first optical element and suppressing total reflection at the interface.

  Furthermore, a fine concavo-convex structure with a wavelength equal to or less than the wavelength of the light source is formed in a predetermined opening formed in the first optical element or a joint where light passes from the first optical element to the second optical element. . Therefore, it is possible to reduce the size of the light source module by reducing the size of the second optical element required for the outgoing light directivity of the secondary light source itself, the illuminance uniformity on the module output surface, and the improvement of directivity. Further, it is possible to improve the polarization characteristics, do not need to provide a separate polarizer, and to reduce the size and cost of the light source module.

  Further, by installing a polarizer on the second surface side of the second optical element and aligning the polarized light, it can be applied to an illumination optical system for a projector using a light valve composed of liquid crystal.

  Furthermore, since the polarizer is a reflective polarizer, the light utilization efficiency can be improved by returning the light beam that has not passed through the polarizer to the first or second optical element and reusing it. .

  Further, since the polarizer is formed on the second surface of the second optical element, the number of parts can be reduced, and the optical module can be thinned.

  Furthermore, since the light source has a luminous flux amount ratio for obtaining a desired white balance, a good white balance can be obtained.

  Moreover, the wiring of the light source can be simplified by connecting the same electrode of the light source that emits the same color.

  Further, since the side surface of the rod that is the first surface and the second surface of the second optical element or the surface that connects the first opening and the second opening is a curved surface, a light beam having a large divergence angle can be all. The light utilization efficiency can be improved without satisfying the reflection condition, forming a reflective film or structure on the side surface of the rod, and the angle of emission from the rod can be made narrower.

  According to another aspect of the present invention, there is provided a projection display apparatus comprising: the light source module; a light modulation element that modulates light emitted from an optical element of the light source module according to image information; and light modulated by the light modulation element. And a projection lens for enlarging and projecting. The light modulation element is preferably a liquid crystal type or mirror type light valve. Therefore, it is possible to provide a lighting device that is excellent in light use efficiency and can be reduced in size, thickness, and weight with a simple configuration, and is small, thin, and light weight equipped with the lighting device, a mobile phone, a portable game machine, and a digital A projection display device that can be incorporated in a portable device such as a camera, an electronic notebook, an electronic book, or a laptop computer, or a small device can be provided.

  According to the light source module of the present invention, the etendue of the light source can be converted, a fine structure can be easily formed on the surface of the secondary light source, directivity and polarization characteristics can be easily controlled, and light utilization efficiency is excellent. It is possible to reduce the size, thickness and weight with a simple configuration.

  FIG. 1 is a schematic sectional view showing a configuration of a projection display apparatus according to a first embodiment of the present invention. The present embodiment shown in the figure is an example of a color-sequential driving projection type color liquid crystal display device. The projection display device 10 according to the present embodiment couples the substrate 11 on which LEDs are arranged and necessary wiring is made, the LED array 12, and the light emitted from the LED array 12, and diffuses them within the element. The first optical element 14 that forms a plurality of secondary light sources 13 having the same amount of emitted light flux, and liquid crystal that is a light modulation means that improves the directivity of the emitted light from the secondary light source 13 and also modulates the illuminance. An image synthesized by the liquid crystal light valve 15 and the second optical element 16 made uniform on the light valve 15, a polarizer 17 for aligning the polarization direction of the light emitted from the second optical element 16 in one direction, and the liquid crystal light valve 15. And a projection lens 18 for enlarging and projecting the image on the screen. The light source module 19 includes the substrate 11, the LED array 12, the first optical element 14, and the second optical element 16.

  Here, the LED array 12 includes LED chips 20 (red), 21 (green), and 22 (blue) that can emit light of each color of R (red), G (green), and B (blue). Each includes one red, two green, and one blue LED chip. In this case, the reason for selecting one red, two green, and one blue is based on reference to p. 77 of the document “Latest Projector Technology” (CMC Publishing). When using LED light sources of the three primary colors of chromaticity coordinates (0.700, 0.299), (0.206, 0.709), and (0.152, 0.026), the light flux ratio is red: green: blue to obtain white color temperature of 9000K. = 21: 76: 4, so two green colors were used. However, since the number of LED chips is not a problem and the light flux ratio is a problem, the number of LEDs that can obtain a necessary light flux ratio may be set. In addition, when a full color is not required, a two-color light source can be used. On the other hand, when higher-definition color expression is required, it is possible to use light sources of four or more colors. Furthermore, when monochrome is acceptable, it is possible to use one color or white LED.

  The LED array 2 is connected to a light source drive circuit (light source drive means) (not shown). The light source drive circuit controls the light emission timing of each LED chip 20, 21, 22 and each LED chip 20, 21, 22 is controlled. To, for example, R, G, B, R, G, B,... At this time, wiring can be simplified by connecting the same terminals of LEDs of the same color on the substrate 1.

  FIG. 2 is a development view when the first optical element in FIG. 1 is a rectangular parallelepiped. In the figure, a surface 31 is a surface having a joint surface 34 with a light source (LED), and a surface 32 is a surface on which secondary light sources 35 (32 secondary light sources are formed in the figure) are formed. The surface 33 is a side surface. In the drawing, a reflective film or a reflective structure for reflecting light from the light source is formed except for the joint surface 34 with the light source and the surface to be the secondary light source 35. Light rays emitted from the LED are emitted in all directions within ± 90 degrees with respect to the emission surface side of the LED and the normal of the emission surface. Therefore, as can be seen from FIG. 3 showing the state of the light beam in the first optical element, the light beam emitted from the LED array 12 is coupled to the first optical element 14, and any light in the first optical element 14 is Radiated in the direction. Among these light beams, the light beam that has reached the aperture to be the secondary light source 13 is emitted from the first optical element 14 as light emitted from the secondary light source 13. The other light rays are repeatedly reflected until they reach the opening to be the secondary light source 13 by the reflective film or the reflective structure applied to the first optical element 14. Therefore, ideally, the light emitted from the LED array 12 is emitted from the secondary light source 13 100%. However, it is difficult to make 100% of the reflectivity of the reflective film or the reflective structure applied to the first optical element, and that amount is lost. Further, a part of the light rays returning to the LED array are lost due to absorption by the material of the LED array. Further, some loss occurs due to the reflectance of the reflective layer (film or structure) applied to the bottom surface of the LED array.

  FIG. 4 is a schematic view showing an assembled state of the LED array and the first optical element. In the figure, the same reference numerals as those in FIG. 1 denote the same components. A transparent resin 41 is filled between the LED chips of the LED array 12 and the first optical element 14 with respect to the emitted LED light. Thereby, compared with the case where the LED emission surface is in contact with air, total reflection in the LED chip is suppressed, and the light extraction efficiency from the LED chip can be improved. Here, the adhesive 42 is an adhesive for fixing the first optical element 14 to the substrate 11. The transparent resin 41 filled between each LED chip and the first optical element 14 may be an adhesive itself, but by filling a transparent medium that is less deteriorated by light or heat, such as silicon resin. Even when used for a long time, it is possible to suppress a decrease in transmittance due to deterioration of the resin.

  FIG. 5 is a schematic view showing the configuration of the second optical element of FIG. In the figure, when there are 16 secondary light sources, the taper rods are in a 4 × 4 array. In this example, the second surface is a common surface, and a two-dimensionally arranged taper rod array is integrated. Each taper rod is coupled to a corresponding secondary light source. The second optical element is made of resin or glass that is transparent to the light source light, and the light beam emitted from the secondary light source repeats internal reflection within the taper rod so that the illuminance has already been made uniform at the output end surface. It becomes. That is, the second optical element functions to improve the directivity of the light beam emitted from the secondary light source and make the illuminance uniform on the tapered rod emission surface. Therefore, a light beam with good directivity and uniform illuminance can be obtained as a whole array. As the directivity, it is preferable to design the angle and length of the taper so that as many rays as possible have an incident angle within ± 15 degrees with respect to the normal of the incident surface of the light valve.

  FIG. 6 is a schematic sectional view showing an example of the configuration of the secondary light source. As shown in the figure, when the size of the secondary light source is a square having a side of 400 μm (□ 400 μm) and the refractive index of the taper rod is n = 1.51 (for example, BK7 glass manufactured by Schott), the light source side of the taper rod When the size of □ is 420 μm, the size on the output side is □ 2 mm, the total length is 5.37 mm, and the output surface side is a spherical surface with a radius of curvature R = 2.92 mm, about 90% of the light beam is ± The incident angle is 15 degrees or less, and the illuminance at a location about 1 mm away from the tapered rod exit surface (where the liquid crystal light valve is installed) can be made substantially uniform. Here, if the size of the secondary light source is reduced, the size of the taper rod for obtaining the same characteristics can be proportionally reduced accordingly, and the overall length can be shortened. For example, when the size of the secondary light source is □ 200 μm, the total length can be halved (about 2.69 mm). However, when the liquid crystal light valves are the same, four times as many taper rods are required.

  Such a taper rod array can be made by injection molding of resin or glass molding. For a mold having a fine array structure such as the taper rod array, a recent precision processing machine (for example, FANUC It has been confirmed that it can be processed by using RoboNano α-0iB).

  Here, the use of light emitted from the light source is formed by forming a reflective film or structure that reflects the light beam having the wavelength of the light source light on the surface connecting the first surface and the second surface of the tapered rod, that is, the side surface of the rod. Efficiency can be improved. Further, as can be seen from FIG. 7 showing another example of the configuration of the secondary light source, by making the side surface an appropriate curved surface, the side surface satisfies the total reflection condition even for a light beam emitted at a large angle with respect to the optical axis. Even if there is no reflecting film or reflecting structure, the loss that passes through the rod can be reduced, and the light utilization efficiency can be improved. Further, by making the side surface of the rod a curved surface, the divergence angle of the emitted light can be kept narrow. The effect of narrowing the divergence angle can also be applied to a hollow rod.

  Then, the light beam emitted from the light source module 19 of FIG. 1 is incident on the liquid crystal light valve 15 with the polarization direction aligned in one direction by the polarizer 17. The liquid crystal light valve 15 uses a TN mode active matrix transmission type liquid crystal cell using a thin film transistor (hereinafter abbreviated as TFT) as a pixel switching element. An incident side polarizing plate and an outgoing side polarizing plate are provided so that their transmission axes are orthogonal to each other. For example, in the off state, s-polarized light incident on the liquid crystal light valve 15 is converted into p-polarized light and emitted, while in the on state, light is blocked. The LED array 12, the first optical element 14, the second optical element 16, the polarizer 17, and the liquid crystal light valve 15 may be arranged apart from each other. However, in order to reduce the size and thickness of the apparatus, It is desirable to arrange all of them in close contact.

  Further, the liquid crystal light valve 15 of FIG. 1 is connected to a liquid crystal light valve driving circuit (light modulation driving means) (not shown), and the liquid crystal light valve corresponding to each incident color light by the liquid crystal light valve driving circuit. 15 can be driven in time sequence. In addition, the projection type display device according to the present embodiment is provided with a synchronization signal generation circuit (synchronization signal generation means). The synchronization signal generation circuit generates a synchronization signal, and a light source driving circuit and a liquid crystal light valve. By inputting to the driving circuit, the timing at which the colored light is emitted from each LED chip 20, 21, 22 in FIG. 1 and the timing at which the liquid crystal light valve 15 is driven in response to the colored light can be synchronized. It has become.

  That is, in the projection type display device 10 according to the present embodiment shown in FIG. 1, one frame is time-divided, and each color light of R, G, B is emitted from the LED chips 20, 21, 22 in order of time. By synchronizing the timing of emitting the color light from 20, 21, 22 and the timing of driving the liquid crystal light valve 15, the liquid crystal light valve 15 is set to the time corresponding to the color light emitted from the LED chips 20, 21, 22. It is configured to be able to synthesize a color image by sequentially driving and outputting an image signal corresponding to the color light emitted from each LED chip 20, 21, 22.

  FIG. 8 is a schematic view of the light source viewed from the first optical element side. In the figure, the same reference numerals as those in FIGS. 1 and 2 denote the same components. As shown in FIG. 8A, the light source may have a configuration in which one array 12 is formed of high-intensity LEDs having a relatively large chip area, but as shown in FIGS. 8B and 8C. In addition, the LED array 12 is configured with a relatively small chip, a plurality of the LED arrays 12 are arranged, the light density in the first optical element is made more uniform, and the illuminance and divergence characteristics of the plurality of secondary light sources 35 are optical. A configuration that makes the characteristics more uniform is also conceivable. Also in these cases, it is desirable that a reflection film or a reflection structure is formed in a portion other than the opening of the light incident / exit portion, and the light is confined in the first optical element.

  Further, as shown in FIG. 9, an inhomogeneous structure having different dielectric constants in the order of microns inside the material, that is, an HSOT polymer (HSOT: Highly Scattering Optical Transmission) that causes multiple scattering due to inclusion of particles 91 By configuring the first optical element 14 with the light scattering optical material, the light density in the first optical element is made more uniform without distributing the light source LEDs, and the illuminance and divergence of the plurality of secondary light sources Optical characteristics such as characteristics can be made more uniform.

  Furthermore, as shown in FIG. 10, it is possible to adopt a configuration in which the light of the LED array 12 is introduced from the side surface of the wedge-shaped first optical element 14 as in the conventional light guide plate. In this case as well, a uniform secondary light source can be formed by using a high light scattering material such as an HSOP polymer. The light scattering optical material may be not only a polymer but also a material having a structure in which particles serving as micron order scatterers are included in glass.

  In general, by forming a fine concavo-convex structure having a wavelength or less on the LED surface, it is possible to improve the light extraction efficiency from the LED or to improve the radiation directivity of light. As described in SID06 DIGEST PP.1808-1811 which is a reference, a photonic crystal is formed on the emission end face of the LED to improve the divergence directivity. Similarly, the divergence directivity can be improved by forming a fine concavo-convex structure of a wavelength or less on the surface of the secondary light source on the first optical element.

  FIG. 11 is a schematic sectional view showing the configuration of a projection display apparatus according to the second embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same components. The configuration of the second optical element 16 is different from that of the first embodiment. In the projection display device 40 of the present embodiment, the second optical element 16 is constituted by a hollow rod. In this case, as shown in FIG. 12, it is necessary to form a reflecting film or reflecting structure 121 that reflects the light source light on the inner surface of the rod. On the other hand, it is necessary to form an opening serving as a secondary light source on the first optical element 14 by forming a reflective film or reflecting structure 122 that reflects light source light on the light source side surface of the second optical element 16. Therefore, it becomes easy to create the first optical element 14. Further, by forming the first and second optical elements as shown in FIG. 13, the first optical element 14 is applied to the first optical element 14 as compared with the case of the rectangular parallelepiped shown in FIG. The reflective film or the reflective structure becomes only the surface bonded to the light source, and the first optical element 14 can be easily created. Further, since the deposition of the reflective film 122 surrounding the surface other than the surface to which the light source of the first optical element 14 is bonded can also be achieved by a single deposition, the creation becomes very easy. In FIG. 13, the first optical element 3 and the second optical element 4 are drawn apart from each other for the sake of explanation, but they are actually bonded by a transparent resin adhesive or the like.

  FIG. 14 is a schematic sectional view showing the structure of a projection display device according to the third embodiment of the present invention. In the figure, the same reference numerals as those in FIG. 1 denote the same components. As shown in the figure, by installing the reflective polarizer 141 on the exit side of the second optical element 16 of the hollow rod, the light of the polarization component that does not pass through the polarizer returns to the first optical element again, Since the light is emitted from the secondary light source again, the light can be recycled and the light use efficiency can be improved.

Here, the structure of the reflective polarizer 141 of FIG. 14 is shown in FIG. A dielectric film 152 having a high refractive index and a dielectric film 153 having a low refractive index are alternately stacked on a glass substrate 151, and a striped periodic structure is formed by etching. For example, the high refractive index material is TaO ₅ (refractive index: n≈2.2), the low refractive index material is SiO ₂ (refractive index: n≈1.44), and the stripe structure pitch p, Filling Factor (land width Δ) / Pitch p) and the layer thickness L are optimized to function as a reflective polarizer that transmits p-polarized light and reflects s-polarized light. Here, by selecting a material having a higher refractive index than that of the high refractive index material and increasing the number of layers, a structure having a function of a reflective polarizer in a wider wavelength range can be created. Further, instead of the dielectric multilayer film, a large number of ribs (light reflectors) made of a metal having light reflectivity such as aluminum may be formed on the exit end face of the rod lens array at a pitch smaller than the wavelength of incident light. Good.

  Such a reflective polarizer may be formed on the exit surface side (panel side) of the second optical element that is not hollow as shown in FIG. Moreover, you may form on the surface of a secondary light source like the above-mentioned photonic crystal.

  As shown in FIG. 16, by installing the microlens array 161 at the outlet of the second optical element 16 of the hollow rod, the length of the rod can be shortened, so that the light source module can be further miniaturized.

  FIG. 17 is a characteristic diagram showing the relationship between the rod length with and without the lens and the rate at which the light emitted from the light source is converted into light within ± 15 degrees. The conditions are as follows: □ 0.5mm surface light source (radiation distribution is Lambert distribution) Tapered rod is 0.5mm on the light source side, □ 3.0mm on the output side, and flat on the output side (R = ∞), and a radius of curvature of 3mm This is a case where a lens (R = 3 mm) is attached. It is shown that the rod length can be shortened by installing a lens.

  Further, as shown in FIG. 18, a configuration in which a reflective polarizer 141 as shown in FIG. 15 is formed on one surface of the microlens array 161 is also conceivable.

  In the rod lens of the first embodiment, the light guide portion is filled with a medium. However, the rod lens of the present embodiment is hollow. Therefore, it is possible to make the rod lens not only with a transparent resin but also with a metal. In this case, there is an advantage that a reflecting surface can be easily formed by mirror-finishing a surface that requires reflection characteristics such as a side surface in the rod and a surface in contact with the first optical element. In addition, when molding with resin, there is an advantage that the mold can be easily created without using the precision processing machine described above. Specifically, a die can be created by making a tapered blade and cutting the die with the blade.

  FIG. 19 is a schematic sectional view showing a configuration of a projection display apparatus according to the fourth embodiment of the present invention. Although the present embodiment is also a color sequential drive type projection display device, the present embodiment uses a mirror type as a light valve instead of a liquid crystal type. In the figure, the same reference numerals as those in FIG. 1 denote the same components. The projection display device 60 of the present embodiment shown in the figure includes a substrate 11, an LED array 12, a first optical element 14, a second optical element 16, a deflection prism 191, a mirror type light valve 192, and a projection lens. 18 is comprised. The light beam emitted from the second optical element 16 is incident on a deflecting prism 191 in which two triangular prisms 193 and 194 are configured so as to have an air layer, and is totally reflected by the inclined surface 195 of the triangular prism 193, thereby producing a mirror-type light. The light enters the bulb 192 at a predetermined angle. For the mirror type light valve 192, a mirror array formed by a semiconductor process can be used as a pixel switching element. In general, a digital mirror device (DMD) manufactured by Texas Instruments is well known. For example, in the off state, the mirror tilt is zero degrees and is not coupled to the projection lens 18, but in the on state, the mirror has a predetermined tilt so that the light beam is reflected in the direction of the projection lens 18. Deviates from the total reflection condition of the inclined surface 195 of the triangular prism 193, passes through the deflecting prism 191, and is imaged on the screen by the projection lens 18. As in this embodiment, when a mirror type light valve is used, since it is possible to take a configuration that does not use polarized light, polarization conversion is not necessarily required, and illumination light can be effectively guided to the projection lens. A bright projection device with high light utilization efficiency can be provided.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, as a light source, a semiconductor laser, an organic EL element, an inorganic EL element, or the like can be used in addition to an LED. The first optical element, the second optical element, the polarizer, the microlens array, and the like may be made of any material such as glass or resin as long as they can perform necessary functions. Further, a configuration using a reflective liquid crystal element (LCOS) as the light valve may be used. Also, the color display method is not limited to the color sequential method of the embodiment, and a pixel division filter method can also be used.

It is a schematic sectional drawing which shows the structure of the projection type display apparatus which concerns on the 1st Example of this invention. FIG. 2 is a development view when the first optical element in FIG. 1 is a rectangular parallelepiped. It is a schematic sectional drawing which shows the mode of the light ray in the 1st optical element of FIG. It is a schematic diagram which shows the assembly | attachment state of an LED array and a 1st optical element. It is the schematic which shows the structure of the 2nd optical element of FIG. It is a schematic sectional drawing which shows an example of a structure of a secondary light source. It is a schematic sectional drawing which shows another example of a structure of a secondary light source. It is the schematic diagram which looked at the light source from the 1st optical element side. It is a schematic sectional drawing which shows the mode of the light ray in the 1st optical element of a nonuniform structure. It is a schematic sectional drawing which shows the structure of a wedge-shaped 1st optical element. It is a schematic sectional drawing which shows the structure of the projection type display apparatus which concerns on the 2nd Example of this invention. It is a schematic sectional drawing which shows the structure of the 2nd optical element of FIG. It is a schematic sectional drawing which shows another shape of the 1st and 2nd optical element. It is a schematic sectional drawing which shows the structure of the projection type display apparatus which concerns on the 3rd Example of this invention. It is a schematic perspective view which shows the structure of the reflection type polarizer of FIG. It is a schematic sectional drawing which shows the example which installed the micro lens array in the exit side of the 2nd optical element. It is a characteristic view which shows the relationship between the rod length with and without a lens, and the ratio by which light source emitted light is converted into light rays within ± 15 degrees. It is a schematic sectional drawing which shows the example which formed the reflective polarizer of FIG. 15 in the single side | surface of a micro lens. It is a schematic sectional drawing which shows the structure of the projection type display apparatus which concerns on the 4th Example of this invention. It is a schematic block diagram which shows the structure of the conventional projection type display apparatus.

Explanation of symbols

10, 40, 50, 60; projection display device,
11, 151; substrate, 12; LED array, 13, 35; secondary light source,
14; first optical element; 15; liquid crystal light valve;
16; second optical element, 17; polarizer, 18; projection lens,
19; light source module, 20-22; LED chip,
31-33; surface, 34; bonding surface, 41; resin, 42; adhesive,
91; particles, 121, 122; reflective film or reflective structure;
141; reflective polarizer, 152, 153; dielectric film,
161; microlens array; 191; deflecting prism;
192; mirror type light valve, 193, 194; triangular prism,
195, 196; slopes.

Claims (20)

In a light source module having a light source and an optical element on which light from the light source is incident,
The optical element is formed with a coupling portion coupled to the light source, a predetermined light emitting portion formed on a surface other than the surface having the coupling portion, and a reflective film or a reflective structure that reflects light from the light source. And a light source module.   The light source module according to claim 1, wherein the optical element is formed of a light scattering optical member including a light scattering body or light scattering particles. In a light source module having a light source, a first optical element on which light from the light source is incident, and a second optical element on which light emitted from the first optical element is incident,
The first optical element includes a first coupling unit coupled to the light source, a second coupling unit coupled to the second optical element, and a reflective film or a reflective structure that reflects light from the light source. Having a formed reflection part,
The second optical element includes a first surface having an area equal to or larger than an area of a coupling portion coupled to the first optical element, an area larger than the first surface, and the first optical element. And a second surface facing the first surface.   There are a plurality of the coupling portions coupled to the first optical element and the second optical element, and the second optical element has two columnar rods with the first surface and the second surface as the bottom surface. 4. The light source module according to claim 3, wherein the light source module is a three-dimensionally arranged rod array.   A reflective film or a reflective structure for reflecting light from the light source is formed on a side surface of the rod, which is a surface connecting the first surface and the second surface of the second optical element. The light source module according to claim 3 or 4. In a light source module having a light source, a first optical element on which light from the light source is incident, and a second optical element on which light emitted from the first optical element is incident,
The first optical element includes a first coupling unit coupled to the light source, a second coupling unit coupled to the second optical element, and a reflective film or a reflective structure that reflects light from the light source. A reflection portion formed,
The second optical element includes a first opening surface, and a second opening surface having an area larger than the first opening surface and facing the first opening surface. A hollow rod whose bottom surface is the second opening surface, and a reflective film or a reflective structure that reflects light from the light source is formed on a side surface of the hollow rod,
A light source module, wherein a reflection film or a reflection structure for reflecting light from the light source is formed on a surface where the first optical element and the second optical element are in contact with each other.   The light source module according to claim 6, wherein the hollow rod array of the second optical element is a two-dimensionally arranged hollow rod array.   The light source module according to claim 3, wherein the first optical element is formed of a light scattering optical member including a light scattering body or light scattering particles.   The light source module according to claim 1, wherein the light source is a light source including a light emitting device that includes at least three colors of red, green, and blue.   The space between the first optical element and the second optical element is transparent to light from the light source, and is filled or bonded with a member having a higher refractive index than air. The light source module according to any one of 3 to 9.   A fine concavo-convex structure having a wavelength equal to or less than the wavelength of the light source is formed in a predetermined opening formed in the first optical element, or in a joint where light passes from the first optical element to the second optical element. The light source module according to claim 3, wherein the light source module is a light source module.   The light source module according to claim 3, wherein a polarizer is installed on the second surface side of the second optical element.   The light source module according to claim 11, wherein the polarizer is a reflective polarizer.   The light source module according to claim 13, wherein the polarizer is formed on a second surface of the second optical element.   The light source module according to claim 1, wherein the light source has a light flux amount ratio for obtaining a desired white balance.   The light source module according to claim 1, wherein the same electrode of the light source that emits the same color is connected.   The side surface of the rod which is a surface connecting the first surface and the second surface of the second optical element or the first opening and the second opening is a curved surface. The light source module according to any one of claims.   The light source module according to claim 1, a light modulation element that modulates light emitted from an optical element of the light source module according to image information, and light modulated by the light modulation element A projection display device, comprising: a projection lens that performs magnified projection.   19. The projection display device according to claim 18, wherein the light modulation element is a liquid crystal type light valve. 19. The projection display device according to claim 18, wherein the light modulation element is a mirror type light valve.

Images