JP2010078975A - Illuminating device and projection type image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminating device using laser light, which obtains uniform illumination light by efficiently coupling the laser light into a rod integrator with a simple method, and to provide a projection type image display device using the illuminating device. <P>SOLUTION: The laser light emitted from a plurality of laser light sources 10, 11 and 12 is condensed at an incident end surface 30a of the rod integrator 30 through a light condensing lens 40. In the rod integrator 30 being an intensity smoothing element, a tapered rod integrator having a light-reflecting side surface and having an incident end surface 30a whose aperture diameter is larger than that of an exit end face 30b is used as the rod integrator 30. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illumination device using laser light, and a projection-type image display device that illuminates an image formed by a spatial light modulation element with laser light and projects the image on a screen using a projection lens.

  As a form for efficiently obtaining a large-screen image, a spatial light modulator such as a small liquid crystal panel that forms an image according to a video signal is illuminated with light from a light source such as a lamp, and is projected by a projection lens. A projection type image display apparatus such as a projector that projects the optical image on a screen in an enlarged manner is used.

  However, when a lamp is used as a light source, (1) the life of the light source is short and maintenance is complicated, (2) the optical system is complicated to separate white light into the three primary colors of light, and (3) the color reproduction range. There are many problems such as narrowness.

  In order to solve these problems, a new image display device using a solid light source such as a laser light source instead of a lamp has been proposed. The laser light source has a longer life than the lamp, and the laser light has high directivity, so that the light utilization efficiency is high. Further, there is an advantage that a wide color reproduction range can be secured by the monochromaticity.

  As a laser light source suitable for an image display device, a semiconductor laser can be given. Since semiconductor lasers are small and suitable for mass production, semiconductor lasers in the visible range have already been put into practical use in the fields of video and audio equipment such as optical disk drive pickups. Further, as a pumping light source such as a YAG laser or a fiber laser, a high-power near-infrared semiconductor laser has been put into practical use in the industry.

  In the red, green, and blue color gamuts for use in image display devices, red and blue semiconductor lasers have entered the stage of practical use. However, many semiconductor lasers having the color gamut that satisfy the characteristics of high efficiency, small size, and high beam quality are currently in the 1 W class.

  As for green, since a semiconductor laser that directly oscillates in the color gamut has not been put into practical use, a method of obtaining green light by a wavelength conversion laser based on the second harmonic is generally used. Several W class lasers have been developed as small green lasers for image display devices using this method.

  By the way, in recent years, the demand for high brightness is remarkable in the projection type image display device, and the full color projection type image display device of 5000 to 10000 lumens is widespread. The luminous flux obtained from 1 W class laser light is 1000 lumens or less, and in order to achieve such a high-luminance image display device with a laser light source, a plurality of laser light sources are required in each color gamut.

  On the other hand, in the projection type image display device, in order to uniformly illuminate the spatial light modulation element, it is necessary to smooth the light intensity in the illumination area. There is a way to use. In the rod integrator, the light is repeatedly reflected on the side surface, whereby the intensity is smoothed on the emission end surface.

Examples of using a semiconductor light emitting element such as a laser as a light source and using a rod integrator for smoothing are disclosed in Patent Document 1 and Patent Document 2, for example.
JP 2006-285043 A JP 2007-114603 A

  In an illumination optical system using a rod integrator, it is important to simultaneously satisfy the following two points: (1) coupling light to the rod integrator without loss and (2) performing sufficient intensity smoothing.

  A simple way to increase the coupling efficiency to the rod is to increase the outer shape of the rod, but in order to ensure a sufficient number of reflections on the side surface, the rod length increases, and as a result, the illumination device There is a problem that the whole becomes large. On the other hand, when the rod outer shape is made small, it is easy to smooth the intensity even with a short rod length, but it becomes difficult to couple the illumination light to the rod.

  In particular, in a projection type image display apparatus using a lamp or LED as a light source, the light emitted from these light sources has a very wide range of light distribution characteristics, and therefore, when the incident end face of the rod is small, high coupling efficiency is obtained. It becomes difficult.

  On the other hand, since laser light has a high light condensing property and a small divergence angle, it is theoretically possible to couple the laser light to a rod having a small incident end face compared to the case where a lamp or LED is used as a light source. Is possible.

  However, since a semiconductor laser suitable for a projection type image display apparatus is a laser light source having a relatively large beam divergence angle, a collimator lens is often used in order to efficiently propagate the laser light. In order to prevent the beam diameter of the collimated light from becoming too large, the collimating lens has a short focal length, and the collimating lens is disposed immediately after the semiconductor laser casing. The laser light that has become substantially parallel light by the collimating lens is incident on a rod integrator that is an intensity smoothing element to obtain uniform illumination light.

  FIG. 11 schematically shows the positional relationship between the semiconductor laser beam, the collimating lens, and the rod integrator. The distance between the semiconductor laser and the collimating lens is Z1, the distance between the collimating lens and the rod integrator is Z2, the optical axis direction in which the laser light propagates is the Z axis, and the paper surface direction perpendicular to the Z axis is the X axis.

  When the collimating lens is moved by ΔX1 in the X-axis direction, the position of the laser beam moves by approximately ΔX2 = ΔX1 × Z2 / Z1 in the X-axis direction at the rod integrator location. Since Z2> Z1 in a general optical system, even if the change of the collimating lens is small, the beam position greatly changes at the rod integrator.

  In other words, when the diameter of the rod integrator is not sufficiently larger than the laser beam diameter at the incident end face, or when Z2 >> Z1, it is necessary to accurately align the semiconductor laser, collimating lens, and rod integrator in the X-axis direction. And

  For such alignment, a collimating lens or laser light source is mounted on a jig provided with a fine movement mechanism of the XYZ axes, and the relative position of the collimating lens and the laser light source is adjusted while observing the reference light, and the desired location It can be achieved by a method of fixing with the above.

  However, in a high-luminance illumination device that requires a plurality of laser light sources, as the number of laser light sources to be used increases, the complexity of assembly and adjustment man-hours becomes a serious problem in systems that require precise alignment.

  The present invention is proposed in view of the above-described circumstances, and in a lighting apparatus using a laser, a laser beam is efficiently coupled to a rod by a simple method to obtain uniform illumination light. It is an object of the present invention to provide an illuminating device that is made possible and a projection type image display device using the same.

  In order to solve the above problems, an illumination device of the present invention includes a plurality of laser light sources that emit laser light, and an intensity smoothing element that smoothes the intensity distribution of the laser light, and the intensity smoothing element includes: Light is reflected from the side surface, and the opening diameter of the incident end face is a tapered rod larger than the opening diameter of the emitting end face, and a plurality of laser beams emitted from the plurality of laser light sources are incident on the intensity smoothing element. It is characterized by.

  In intensity smoothing using a rod, there is a rod (hereinafter referred to as a straight rod in the present invention) in which the opening diameter of the incident end face is equal to the opening diameter of the exit end face as disclosed in Patent Document 1 and Patent Document 2. Widely used.

  In contrast, a tapered rod having an opening diameter at the incident end face larger than the opening diameter at the exit end face means that the traveling direction of the light beam in the rod is the Z axis, and the surface of the intensity smoothing element facing the light source. When the X axis and the Y axis are taken inside, at least one of the side surfaces (YZ surface and XZ surface) along the Z axis is formed into a tapered shape that gradually decreases in width as the distance from the opposing surface increases. Indicates that

  With the above configuration, increasing the opening diameter of the incident end face of the tapered rod facilitates coupling of the laser light to the rod, and the opening diameter of the exit end face is reduced. In addition, the number of reflections can be increased compared to straight rods having the same rod length.

  The above configuration is also possible in an illumination optical system using various lamp lights and LED lights. However, since these light sources have a wide angle light distribution characteristic, the NA (Numerical Aperture) of the rod incident light is used. ) Is large. Therefore, when the taper rod of the present invention is applied, the emitted light NA from the rod becomes too large, which is not suitable.

  That is, the configuration of the present invention is a laser beam that can be collimated with a beam diameter thinner than that of a lamp or LED. In particular, laser beams from a plurality of laser light sources are desired to be simplified in assembly adjustment. It is suitable for an illumination optical system that is incident on the beam.

  As a secondary effect of the present invention, there is a reduction in speckle noise. Since laser light has high coherence, there is a problem that speckle noise occurs and image quality deteriorates. When providing an image display device using laser light, it is extremely important to remove and reduce speckle noise. It is.

  One factor that affects the amount of speckle noise is the NA of the optical system. When the NA of the optical system is increased, speckle noise is reduced because light is projected to a point on the screen from various angles. Therefore, it is desirable from the viewpoint of speckle noise reduction to use an optical system having a large NA by the method of the present invention as long as no loss occurs in the illumination optical system, the spatial modulation element, and the projection optical system.

  In the illumination device of the present invention, the intensity smoothing element has a rectangular cross-sectional shape perpendicular to the optical axis, and has an emission end face width smaller than an incident end face width in at least one side direction of the cross section. To do. In the prismatic rod, it is possible to obtain highly efficient and highly uniform illumination light by forming a tapered shape whose exit end face width is smaller than the entrance end face width in at least one of the X-axis direction and the Y-axis direction. .

  Since the shape of the display portion of the two-dimensional spatial light modulator is generally rectangular, it is often effective to use a prismatic rod as the shape of the rod, but the rod of the rod applicable to the illumination device of the present invention is often used. The shape is not limited to this, and may be a circular rod having a circular cross section or a polygonal rod having a polygonal cross section. In short, any taper as described above may be used.

  The taper rod of the present invention includes a hollow light guide having a metal mirror, a dielectric mirror, etc. arranged on the side surface in addition to a medium-density light guide by total reflection using prismatic glass or crystals. It is.

  Next, in the illumination device of the present invention, the laser light source is configured by a laser light source that emits red, green, and blue color gamuts. In particular, the red, green, and blue laser light sources have respective colors. It is characterized in that it is composed of a plurality of laser light sources.

  The present invention is suitable for a full-color illuminating device in which the number of laser light sources to be used is large, particularly in a high-luminance illuminating device using a large number of laser light sources in each color gamut.

  The wavelength of the red color gamut laser light is not particularly limited, but is, for example, laser light having a center wavelength in the range of 610 to 650 nm. Similarly, the green and blue color gamut laser beams are, for example, laser beams having center wavelengths of 510 to 550 nm and 430 to 480 nm, respectively.

  Further, the illumination device of the present invention is characterized in that the intensity smoothing element is arranged for each laser light source that emits the red, green, and blue color gamuts. In order to provide a full-color image display apparatus, laser light sources of three colors of red, green, and blue are used. When two-dimensional spatial light modulation elements that are independent for each color are used, The intensity smoothing element having an appropriate taper angle may be used for each laser beam.

  Furthermore, in the illumination device of the present invention, the intensity smoothing element is constituted by a plurality of smoothing elements arranged in series, or the phase of the laser beam is changed between the plurality of smoothing elements. It is characterized by having a phase modulation means for modulating, or having a phase modulation means for modulating the phase of the laser light between the laser light source and the intensity smoothing element.

  The projection-type image display device using the illumination device of the present invention modulates the laser light emitted from the illumination device by a spatial light modulation element that modulates according to the video signal, and modulates the laser light emitted from the spatial light modulation device. It is a projection type image display apparatus which projects a laser beam via a projection optical system.

  According to the present invention, it is possible to obtain a small, high-brightness, high-efficiency, and highly uniform illumination device using a laser beam, and further, a projection type in which speckle noise is suppressed. An image display device can be provided.

  More specifically, the following effects can be obtained by using a tapered rod having an entrance end face diameter larger than the exit end face diameter as an intensity smoothing element for smoothing the intensity distribution of the laser light.

  (1) Since the diameter of the incident end face is large, the coupling efficiency to the rod is increased, so that the mounting position accuracy of the laser light source, the collimating lens, and the like is eased.

  (2) Since the exit end face diameter is small, a sufficient strength smoothing effect can be obtained even if the rod length is short, and the illumination optical system after the rod can be miniaturized, so that a small illumination device can be provided. .

  (3) Since it becomes easy to use a plurality of laser light sources by simple assembly and adjustment, a high-luminance illumination device can be provided.

  (4) By providing the smoothing element with an NA expansion function, illumination light having a large NA can be obtained effectively, and speckle can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram illustrating an illumination device according to Embodiment 1 of the present invention and an image display device using the same.

  In this embodiment, laser light sources of three colors of red, green, and blue are used, the red laser light source 10 is a semiconductor laser that directly oscillates at a wavelength of 640 nm, and the green laser light source 11 is Yb that is output at a wavelength of 532 nm. The second harmonic of the fiber laser, the blue laser light source 12, is a semiconductor laser that directly oscillates at a wavelength of 445 nm.

  However, it goes without saying that a laser light source suitable for the present invention is not limited to the laser light source shown in this embodiment mode. For example, the red laser light source 10 includes a second harmonic of a near-infrared semiconductor laser. Examples of the green laser light source 11 include a semiconductor laser that directly oscillates in green, a second harmonic of a near-infrared semiconductor laser, a second harmonic of an Nd: YAG laser, and a second harmonic of an Nd: YVO4 laser. . Examples of the blue laser light source 12 include a second harmonic of a near-infrared semiconductor laser.

  In any laser light source, when the beam divergence angle from the light source is large, it is preferable to use a collimating lens in order to propagate the laser beam efficiently. Therefore, the laser beams 13, 14 and 15 emitted from the laser light sources 10 to 12 of the respective colors are made into substantially parallel beams by the collimating lenses 20 to 22 and are incident on the condenser lens 40.

  In the present embodiment, aspherical lenses that are rotationally symmetric with respect to the optical axes of the laser beams of the respective colors are used as the collimating lenses 20 to 22, but the beam divergence angles in the vertical direction and the horizontal direction are significantly different. In an output semiconductor laser or the like, it may be desirable to use an anamorphic optical system such as a cylindrical lens as a collimating lens.

  The three, red, green, and blue laser beams 13, 14, and 15 are collected by the condenser lens 40, pass through the phase modulation element 50, and enter the rod integrator 30 that is an intensity smoothing element. The laser beams 13, 14, and 15 are arranged so that the optical axes of the respective beams are substantially parallel after being emitted from the collimator lens, and the incident end face 30 a of the rod integrator 30 is approximately coincident with the focal point of the condenser lens 40. Yes.

  The phase modulation element 50 is composed of a rotating microlens array, and speckle noise generated on the screen 71 is reduced by inserting this element. Examples of the phase modulation element other than the microlens array include a diffusion plate.

  The rod integrator 30 is a rectangular column-shaped light guide with a rectangular shape in which the shape of the incident end face 30a and the shape of the outgoing end face 30b are substantially similar, and the tapered end face 30b is smaller than the incident end face 30a. Shaped rod. The shape of the rod is shown in the schematic diagram of FIG. 2A, 2B, 2C, and 2D are a plan view, a side view, an incident-side end view, and an exit-side end view, respectively. The aspect ratio of the rod end face is approximately 4: 3.

  In the present embodiment, the rod length L0 is set to about 7 times the diagonal length L2 of the emission end face 30b. However, the ratio of the lengths of the three rod sides can be appropriately selected according to the purpose. The rod material is quartz, and an antireflection coating is applied to the incident end face 30a and the outgoing end face 30b.

  The laser light emitted from the rod integrator 30 is relayed to the digital micromirror device 62 which is a spatial light modulation element by the relay optical system 60 and the total reflection mirror 61. The modulated laser light emitted from the digital micromirror device 62 is projected onto the screen 71 by the projection optical system 70.

  In this apparatus, the configuration from the light source to the relay optical system 60 is an illuminating device, and this illuminating device can also be used independently. The same applies to the second and subsequent embodiments described below.

  In the present embodiment, since the incident end face 30a of the rod integrator 30 is large, it is easy to couple the laser beams 13, 14, and 15 to the rod integrator 30.

  Further, since the exit end face 30b is small, the number of reflections can be increased, and the NA of the rod exit light can be increased. These are effective in improving the illumination uniformity, downsizing the lighting device, and reducing speckle noise.

(Embodiment 2)
FIG. 3 is a configuration diagram illustrating an illumination device and an image display device using the illumination device according to Embodiment 2 of the present invention.

  In this embodiment, red, green, and blue laser beams are spatially synthesized by a color synthesis prism and then incident on a rod integrator that is an intensity smoothing element.

  The red laser light source module 100 is composed of at least one red laser light source. Similarly, the green laser light source module 101 is composed of at least one green laser light source, and the blue laser light source module 102 is composed of at least one blue laser light source.

  The laser beams 13, 14, and 15 emitted from the laser light source modules are spatially combined by the color combining prism 403, pass through the phase modulation element 50, and then enter the rod integrator 30. The optical system from the phase modulation element 50 to the screen 71 is the same as in the first embodiment.

  In this embodiment, the use of the color combining prism 403 increases the degree of freedom with respect to the arrangement of the laser light sources, and facilitates driving and cooling of laser light sources having different specifications for each color.

  FIG. 4 shows the details of the laser light source module 101 to the rod integrator 30 in the case where the light source module is composed of a plurality of laser light sources in the lighting apparatus according to the present embodiment, taking a green light source module as an example. FIG.

  In the present embodiment, nine laser light sources 110 to 118 are simultaneously used as the green laser light source module 101, and the vertical 3 × horizontal 3 are arranged at equal intervals on the plane. FIGS. 5A, 5B, and 5C are a plan view, a side view, and an incident side end view, respectively.

  Laser light sources 110 to 118 serving as light source elements are collimated with collimating lenses 120 to 128 after being collimated with emitted light, and then condensed onto the rod integrator 30 using a condensing lens 401.

  In this embodiment, the collimating lenses 120 to 128 are axisymmetric aspherical lenses, but as described above, the beam divergence angles in the vertical and horizontal directions of the emitted light from the laser light sources 110 to 118 are large. If they are different, a cylindrical lens or the like may be used. Further, when the beam divergence angle of the emitted light from the laser light sources 110 to 118 is small, the collimating lenses 120 to 128 need not be used.

  The rod integrator 30 is arranged so that the incident end face 30 a is at a substantially rear focal position of the condenser lens 401. Between the condenser lens 401 and the rod integrator 30, a rotating microlens array 50, which is a phase modulation element, is inserted immediately before the rod incident end face 30a. The shape of the rod integrator 30 is the same as that shown in FIG. 2, and is a tapered prismatic rod whose exit end face 30b is smaller than the entrance end face 30a and whose shapes are substantially similar.

  When using a plurality of laser light sources for each color, it is necessary to focus each laser light at one place on the rod incident end face 30a, but as the number of laser light sources increases, alignment of each laser light becomes complicated, The optical axis variation between elements also increases. By enlarging the incident end face 30a of the rod integrator 30, the coupling of the laser beam to the rod can be facilitated, and a highly efficient illumination device can be provided.

  Here, the preferable apertures of the entrance end face 30a and the exit end face 30b of the rod integrator 30 will be described. The upper limit of the divergence half angle of the emitted light in the rod integrator 30 that can efficiently propagate the optical system from the rod integrator 30 to the projection optical system 70 without loss is θ2 (that is, the optical system NA = sin (θ2)). To do.

  Further, laser light when the laser light source (the laser light sources 110, 116, 112, and 118 in FIG. 4) that is farthest from the optical axis of the rod integrator 30 is condensed on the rod integrator 30 by the condenser lens 401. Is incident angle θ1.

At this time, as shown in FIG. 2, when the entrance end face diameter of the rod integrator 30 is L1, and the exit end face diameter is L2,
L1 / L2 ≦ θ2 / θ1 (1)
It is preferable to satisfy the relationship. By selecting L1 and L2 of the rod so that the relationship of Expression (1) is satisfied, light can be efficiently propagated without causing a significant loss in the optical system after the rod.

Furthermore, when light is diffused or condensed / diverged by the phase modulation element 50, it is preferable to select the relationship between L1 and L2 in consideration of the influence. When the divergence angle of the phase modulation element 50 is θ3,
L1 / L2 ≦ θ2 / (θ1 ^ 2 + θ3 ^ 2) ^ 0.5 Formula (2)
It is preferable to satisfy the relationship.

  In general, since the color combining prism 403 having a rectangular parallelepiped shape transmits P-polarized light with high efficiency, the laser light sources 110 to 118 are preferably arranged so as to be all emitted with P-polarized light.

  In FIG. 4, the arrangement of the light source elements is described only for the green laser light source module 101, but the red laser light source module 100 and the blue laser light source module 102 can be similarly configured from a plurality of light source elements. . In each color, the number of laser light sources need not be the same.

  However, since the color combining prism 403 reflects S-polarized light with high efficiency, as shown in FIG. 3, when the laser light from the red and blue laser light source modules is reflected by the color combining prism, The red laser light source module 100 and the blue laser light source constituting the blue laser light source module 102 are preferably arranged so as to be emitted as S-polarized light.

  The color combining prism 403 is not limited to a so-called cross prism having a rectangular parallelepiped shape, and a Philips type prism, a Kester type prism, or the like is also suitable.

  A preferred embodiment in the case where a plurality of laser light sources are arranged in one light source module will be additionally described. In order to minimize the unevenness of illumination of the light emitted from the rod integrator 30, when the output of the light source element is substantially equal, rotational symmetry is achieved with respect to the straight line 200 parallel to the Z axis represented by the XY cross-sectional center of the taper rod. It is desirable to have. That is, it is preferable to arrange n-fold symmetry (n ≧ 2) or a geometric positional relationship close to it with respect to the straight line 200, and it is more preferable that n is a large number.

  In FIG. 4, laser light sources 114 are arranged on a straight line 200, and the arrangement of the remaining eight laser light sources is four-fold symmetric (90-degree rotational symmetry) with respect to the straight line 200.

  Thus, by arranging the laser light source without deviation with respect to the straight line 200, that is, the optical axis of the rod integrator 30, it is possible to construct an illumination device with little unevenness.

(Embodiment 3)
FIG. 5 is a configuration diagram illustrating an illumination device and an image display device using the same according to Embodiment 3 of the present invention.

  In this embodiment, a plurality of laser light sources are used for at least one of red, green, and blue. The schematic configuration for explaining the illumination device according to the present embodiment and the image display device using the same is the same as that in FIG. 3 of the second embodiment.

  In the illumination device according to the present embodiment, as in FIG. 4 of the second embodiment, the case where the green laser light source module is configured by a plurality of laser light sources is described in detail from the laser light source module 101 to the rod integrator 30. FIG. 5 shows a configuration diagram to be described.

  In the present embodiment, five laser light sources 130 to 134 are simultaneously used as the green laser light source module 101, the optical axis is the Z-axis direction, and the laser light sources are linear and equidistant in parallel to the X axis. Has been placed. FIGS. 5A and 5B are a plan view and a side view, respectively.

  About each light source element, after collimating the emitted light with the collimating lenses 140 to 144, the light is condensed on the rod integrator 30 using the condensing lens 401. The arrangement of the condenser lens 401, the phase modulation element 50, and the rod integrator 30 is the same as in the second embodiment.

  The rod integrator 30 used in the present embodiment is a prismatic tapered rod whose area of the exit end face 30b is smaller than that of the entrance end face 30a, but the taper angle is different between the X axis direction and the Y axis direction. The end face 30a and the emission end face 30b are not similar.

  When the laser light source is arranged in the X-axis direction, when considering the light beams of a plurality of laser beams together, the NA in the X-axis direction of the incident light to the rod integrator 30 is greater than the NA in the Y-axis direction. large. Therefore, by making the taper angle of the rod integrator 30 larger than the taper angle in the Y-axis direction than the taper angle in the X-axis direction, the difference in NA between the X-axis direction and the Y-axis direction is emitted from the rod integrator 30. Is made smaller. Alternatively, only the Y-axis direction may be tapered.

  In this embodiment, when the laser light source is arranged on a straight line, by increasing the taper angle in the small axial direction of the incident light NA based on the difference between the X-axis direction and the Y-axis direction NA of the rod incident light, An effective lighting device can be provided.

(Embodiment 4)
FIG. 6 is a schematic configuration diagram for explaining an illumination device and an image display device using the illumination device according to Embodiment 4 of the present invention.

  In the present embodiment, a two-dimensional spatial light modulator and a rod integrator are used for red, green, and blue laser beams, respectively.

  At least one of the laser light source modules 100 to 102 includes a plurality of laser light sources as described in FIG. 4 of the second embodiment or FIG. 5 of the third embodiment.

  The red laser light emitted from the red laser light source module 100 is collected by the condenser lens 400, passes through the phase modulation element 51, and enters the rod integrator 31 that is an intensity smoothing element. The red laser light emitted from the rod integrator 31 illuminates the two-dimensional spatial light modulator 83 via the relay optical system 80. With respect to the green laser beam and the blue laser beam, the two-dimensional spatial light modulators 84 and 85 are illuminated with the same configuration, respectively.

  The laser beams modulated by the two-dimensional spatial light modulators 83 to 85 are spatially combined by the color synthesis prism 86 and projected onto the screen 71 by the projection optical system 70.

  In this embodiment, a transmissive liquid crystal display device is used for each color as the two-dimensional spatial light modulation element, and a separate rod integrator is also used for the intensity smoothing element for each color. Therefore, it is possible to select an appropriate incident end face diameter and outgoing end face diameter of the intensity smoothing element of each color according to the characteristics of the laser light source module of each color.

  In the configuration shown in FIG. 6, all the strength smoothing elements are tapered rods, but some of the rods may be changed to straight rods as necessary.

(Embodiment 5)
FIG. 7 is a schematic configuration diagram for explaining an illumination apparatus and an image display apparatus using the illumination apparatus according to Embodiment 5 of the present invention.

  In this embodiment, a plurality of laser light sources are used for at least one of red, green, and blue. The configuration diagram for explaining the illumination device according to the third embodiment of the present invention and the image display device using the same is the same as FIG. 3 of the second embodiment except that the condenser lenses 400 to 402 are not used. It is.

  In the illumination device according to the present embodiment, as in FIG. 3, in the case where the green light source module is configured by a plurality of laser sources, a configuration diagram illustrating in detail from the laser source module 101 to the rod integrator 30 is provided. FIG.

  In the present embodiment, five laser light sources 130 to 134 are simultaneously used as the green laser light source module 101. Although the laser light sources are arranged at equal intervals, when the optical axis of the rod integrator 30 is set to the Z-axis direction, the light emitted from each laser light source is not parallel to the Z-axis except for the laser light source 132.

  When the output of each laser light source is large, the laser light is condensed by a condensing lens and the incident end face 30a of the rod integrator 30 or the phase modulation element 50 is disposed near the focal point. In addition, there is a risk of damage to the element end face. Therefore, in the present embodiment, the laser light is incident on the phase modulation element 50 with substantially collimated light without using a condenser lens. Thereby, the light density in the rod entrance end face 30a can be kept low.

  In FIG. 7, the incident end face of the intensity smoothing element exists on an extension line connecting the light emitting point of each laser light source and the optical axis of the collimating lenses 140 to 144. However, a mirror is provided between the collimating lens and the intensity smoothing element. Alternatively, the optical path may be bent by arranging a prism. Further, when the beam divergence angle from the laser light source is small, the collimating lens may not be used.

(Embodiment 6)
FIG. 8 is a schematic configuration diagram for explaining an illumination apparatus and an image display apparatus using the illumination apparatus according to Embodiment 6 of the present invention.

  In the present embodiment, a red laser light source 10, a green laser light source 11, and a blue laser light source 12 are connected to optical fibers 150 to 152, and lasers of each color are emitted from the emission end faces of the optical fibers 150 to 152. Light is output. An incident end face 30a of the rod integrator 30 is disposed in the vicinity of the exit end faces of the optical fibers 150 to 152.

  In the propagation of laser light, an optical fiber is often used from the viewpoint of easy handling. By propagating through the optical fiber, the degree of freedom of arrangement of the laser light sources 10 to 12 becomes extremely high. In FIG. 8, the laser light sources are arranged on a straight line, but this arrangement method is not particularly limited. Further, by using the optical fiber, it becomes easy to directly couple the laser light to the rod integrator without using a lens or the like.

  The diameter of the optical fiber varies depending on the type of fiber. As the multimode fiber, for example, a generally used fiber having a core diameter of 0.9 mm can be applied.

  In principle, the diameter of the optical fiber cable can be reduced to the fiber clad diameter, but the bundle diameter increases as the number of optical fibers bundled. Coupling can be performed.

  In FIG. 8, one optical fiber is used for each of red, green, and blue, but each color can be extended to a plurality of optical fibers. In that case, in order to suppress unevenness of illumination to the minimum, the arrangement of the optical fiber exit end face is n-fold symmetric (n ≧ 2) or close to the optical axis of the taper rod for each color. It is preferable to arrange with positional symmetry.

  Here, it is more preferable that n is a large number. For example, in the example shown in FIG. 9, a total of nine fiber output lights are input to one taper rod. FIGS. 9A and 9B are a plan view and an incident side end view, respectively. A fiber output end face 154 of the green laser is arranged on a straight line 200 represented by the center of the XY cross section of the rod integrator 30.

  Four fiber output end faces (fiber output end faces 150, 152, 156, 158) of the red laser are arranged in a four-fold rotationally symmetrical positional relationship with the straight line 200 as the rotation center. Similarly, four fiber output end faces (fiber output end faces 151, 153, 155, 157) of the blue laser are also arranged in a four-fold rotationally symmetric positional relationship.

  In this way, it is possible to construct an illumination device with less unevenness by arranging the fiber output end face without deviation.

  In this embodiment, all the fiber output lights of red, green, and blue are coupled to one taper rod, but a rod integrator is used for each color as shown in FIG. It is good also as a structure which couples fiber output light.

  It is also possible to insert phase modulation means between the fiber output end face and the rod integrator.

(Embodiment 7)
FIG. 10 is a configuration diagram for explaining a part of a lighting apparatus according to Embodiment 7 of the present invention. In this embodiment, two rods are used in series.

  The rod used in any of the first to sixth embodiments described above can be applied by replacing it with the series rod group in the seventh embodiment.

  FIG. 10 (a) uses a single taper rod as the rod integrator 300, and has the same device configuration as the rod integrator 30 in each of the above-described embodiments. In FIG. 1, one taper rod and one straight rod are used, a taper rod is disposed as the first rod integrator 301 on the incident side, and a straight rod is disposed as the second rod integrator 302 on the outgoing end side.

  The shape of the first rod integrator 301 is the same as that shown in FIG. 2 of the first embodiment. The first rod integrator 301 is a tapered prismatic rod that has an exit end surface 301b smaller than the entrance end surface 301a and is substantially similar to both. is there.

  The outgoing light from the first rod integrator 301 continues to enter the second rod integrator 302. The incident end surface 302a of the second rod integrator 302 is substantially the same in shape and size as the exit end surface 301b of the first rod integrator 301. By arranging the two rods close to each other, light propagation loss is achieved. Does not occur.

  Thus, by dividing the rod integrator into two parts, the number of reflections on the rod is increased compared to the single rod integrator 300 having the same entrance / exit end face diameter and rod length shown in FIG. And effective illumination uniformity can be achieved.

  Further, as shown in FIG. 10C, a phase modulation element 51 can be inserted between the first rod integrator 301 and the second rod integrator 302 in FIG. Examples of the phase modulation element described here include a microlens array, a diffusion plate, and a wavelength plate, and these may be temporally modulated by rotating or vibrating them.

  Further, as shown in FIG. 10 (d), the second integrator 303 is a tapered rod whose entrance end face 303a has substantially the same diameter and size as the exit end face 301b of the first integrator, and between the two rod integrators. A configuration in which the phase modulation element 51 is inserted may also be mentioned.

  In any of the embodiments shown in FIGS. 10B to 10D, the laser beam can be directly incident on the first rod integrator 301 without using the phase modulation means 50.

  The illumination device of the present invention can couple laser light to a rod integrator by using a tapered rod having an entrance end face diameter larger than an exit end face diameter as an intensity smoothing element that smoothes the intensity distribution of the laser light. It becomes easy and can provide illumination light with high brightness and high uniformity and low speckle noise by a simple method, and is useful for an image display device such as a projector using a laser light source.

1 is a schematic configuration diagram of an image display device according to Embodiment 1 of the present invention. 1 is a schematic diagram of a rod integrator according to Embodiment 1 of the present invention. Schematic configuration diagram of an image display apparatus according to Embodiment 2 of the present invention. Schematic configuration diagram of a laser light source module in Embodiment 2 of the present invention Schematic configuration diagram of a laser light source module according to Embodiment 3 of the present invention. Schematic configuration diagram of an image display apparatus according to Embodiment 4 of the present invention. Schematic block diagram of a part of a lighting apparatus according to Embodiment 5 of the present invention Schematic configuration diagram of an image display apparatus according to Embodiment 6 of the present invention. Schematic configuration diagram of the fiber output section in the sixth embodiment of the present invention Schematic configuration diagram of a rod integrator in Embodiment 7 of the present invention Schematic diagram showing the position variation of the rod integrator incident light due to the position variation of the collimating lens

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Red laser light source 11 Green laser light source 12 Blue laser light source 13 Red laser light 14 Green laser light 15 Blue laser light 20-22 Collimating lens 30-32 Rod integrator 30a, 31a, 32a Rod integrator incident end face 30b, 31b, 32b Rod integrator Output end face 30c Rod integrator side face 40 Condensing lens 50, 51 Phase modulation element 60 Relay optical system 61 Total reflection mirror 62 Digital micromirror device 70 Projection optical system 71 Screen 80-82 Relay optical system 83-85 Transmission type liquid crystal panel 86 color combining prism 100 red laser light source module 101 green laser light source module 102 blue laser light source module 110 to 118 green laser light source 120 to 128 collimator 130 to 134 Green laser light source 140 to 144 Collimating lens 150 to 158 Optical fiber 200 Rod integrator optical axis 300 to 303 Rod integrator 300a, 301a, 302a, 303a Rod integrator incident end face 300b, 301b, 302b, 303b Rod integrator emitting end face 400 ~ 402 Condensing lens 403 Color composition prism

Claims (15)

An illumination device comprising a plurality of laser light sources that emit laser light and an intensity smoothing element that smoothes the intensity distribution of the laser light, wherein the intensity smoothing element reflects light at a side surface and is incident An illumination device, wherein the opening diameter of the end face is a taper rod integrator larger than the opening diameter of the emission end face, and a plurality of laser beams emitted from the plurality of laser light sources are incident on the intensity smoothing element . 2. The intensity smoothing element according to claim 1, wherein a cross-sectional shape perpendicular to the optical axis is rectangular, and an emission end face width is smaller than an incident end face width in at least one side direction of the cross section. Lighting device. A laser light source comprising a condensing lens for condensing the light from the plurality of laser light sources, wherein the upper limit of the divergence half angle of the emitted light in the intensity smoothing element is θ2, and the laser light source is located farthest from the optical axis of the intensity smoothing element When the incident angle of the laser beam when being condensed on the intensity smoothing element by the condenser lens is θ1, the entrance end face diameter of the intensity smoothing element is L1, and the exit end face diameter is L2, the following formula The lighting device according to claim 1, wherein the relationship is satisfied.
L1 / L2 ≦ θ2 / θ1 The illumination device according to any one of claims 1 to 3, wherein the laser light source is configured by a laser light source that emits red, green, and blue color gamuts. The illumination device according to claim 4, wherein the red, green, and blue laser light sources include a plurality of laser light sources in respective color gamuts. 6. The illumination device according to claim 4, wherein the intensity smoothing element is arranged for each laser light source that emits the red, green, and blue color gamuts. The illumination device according to claim 1, wherein the laser light source includes a semiconductor laser. The illumination device according to any one of claims 1 to 7, wherein a collimating lens is disposed at an emission position of the laser light source. The illumination device according to claim 8, wherein the collimating lens is an aspheric lens. The illumination device according to claim 8, wherein the collimating lens is an anamorphic optical system lens. The lighting device according to any one of claims 1 to 10, wherein the intensity smoothing element includes a plurality of smoothing elements arranged in series. The illumination device according to claim 11, further comprising a phase modulation unit that modulates a phase of the laser light between the plurality of smoothing elements. The lighting device according to claim 11 or 12, wherein at least one of the plurality of smoothing elements is a tapered rod having an opening diameter of an incident end face larger than an opening diameter of an exit end face. 14. The illumination device according to claim 1, further comprising: a phase modulation unit that modulates a phase of the laser light between the laser light source and the intensity smoothing element. . A projection-type image in which laser light emitted from an illumination device is modulated by a spatial light modulation element that modulates according to a video signal, and the modulated laser light emitted from the spatial light modulation element is projected through a projection optical system It is a display apparatus, Comprising: The said illuminating device is an illuminating device in any one of Claims 1-14, The projection type image display apparatus characterized by the above-mentioned.

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