JP2010122581A - Projection display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection display device for improving uniformity of illuminance distribution with a compact configuration, even in an optical system adopting a multi-primary-color light source. <P>SOLUTION: In the projection display device which includes a light source 4 and a light intensity uniforming element for uniforming the intensity distribution of a luminous flux emitted from the light source 4 and projects and displays an image by using the luminous flux emitted from the light intensity uniforming element, the light intensity uniforming element 6 is configured in such a manner that light intensity uniforming parts 61 and 62 uniforming the intensity distribution are joined to each other in the direction of an optical axis 1a, the light intensity uniforming part 61 has such a taper shape that the area of the cross-section is decreased as it goes in the direction of the optical axis 1a and the light intensity uniforming part 62 has such a taper shape that the area of the cross-section is increased as it goes in the direction of the optical axis 1a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a projection display device that projects and displays an image on a screen.

  In a projection display device, it is desired to display a bright image with uniform light intensity on a screen. For this reason, it is necessary to efficiently guide the light beam generated from the light source to the screen while maintaining the uniformity of the light intensity (illuminance distribution). A conventional projection display device uses a light pipe (cylindrical optical element) to guide a light beam from a light source to a light valve.

  For example, the projection display device described in Patent Document 1 is formed with a tapered portion formed so that a cross-sectional area continuously decreases on the incident port side and a cross-sectional shape constant on the output port side. And a light tunnel having a parallel portion. The light pipe is a light intensity uniformizing element that repeatedly reflects incident light in the light pipe and emits the light, and light of various wavelengths are mixed in the light pipe. For this reason, the number of times of reflection of light within the light pipe greatly contributes to uniform light intensity, and the length of the light pipe is important. In other words, the light pipe has a light intensity uniformity determined by its length. For this reason, when producing a projection display device, the length of the light pipe is determined based on the light intensity uniformity required for the projection display device.

  By the way, the projection display device employs a multi-primary color light source such as a laser light source or an LED light source because it has an advantage that it has a long life and does not require maintenance work and can widen a color reproduction range. Optical systems have been proposed. When such a multi-primary light source is employed, it is required to make the light intensity uniform in the light pipe in order to sufficiently mix the luminous flux.

Japanese Patent Laying-Open No. 2004-252112 (paragraph 0034, FIG. 2)

  However, in the above conventional technique, even if the tapered portion is provided, the effect of uniforming the light intensity is hardly changed. Therefore, in order to equalize the light intensity, it is necessary to lengthen the light pipe. Increasing the length of the light pipe increases the configuration of the projection display device, greatly affects the layout, and increases the cost.

  The present invention has been made in view of the above, and provides a projection display device that can improve the uniformity of illuminance distribution with a small configuration even in an optical system employing a multi-primary light source. Objective.

  In order to solve the above-described problems and achieve the object, the present invention includes a light source and a light intensity uniformizing element that uniformizes an intensity distribution of a light beam emitted from the light source, and the light intensity is uniform. In the projection display apparatus that performs projection display of an image using a light beam emitted from the conversion element, the light intensity uniformization element includes a plurality of light intensity uniformization sections that join the intensity distribution in the optical axis direction. And at least one of the light intensity uniformizing portions has a tapered shape in which an area of a cross-sectional shape increases or decreases toward the optical axis direction.

  According to this invention, the light intensity uniformizing element is composed of a plurality of light intensity uniformizing sections, and at least one of the light intensity uniformizing sections has a tapered shape toward the optical axis direction. Even in an optical system employing a multi-primary color light source, it is possible to improve the uniformity of the illuminance distribution with a small configuration.

  Embodiments of a projection display device according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a schematic configuration of an optical system of a projection display apparatus according to Embodiment 1 of the present invention. The projection display device 1 is a projection image display device that projects an image on a screen using a light valve. In the projection display device 1, a light intensity uniformizing element 6 to be described later is composed of a plurality of light intensity uniformizing sections having different shapes, and at least one of the light intensity uniformizing sections is arranged in the optical axis direction (from the light incident side). A tapered shape in which the area of the cross-sectional shape continuously decreases or increases toward the emission side) is set.

  The projection display device 1 includes a light source 4, a light intensity uniformizing element 6, an illumination optical system 7, a reflective light valve (reflective light modulation element) 2, and a reflective light illuminated by the illumination optical system 7. And a projection optical system 3 that projects an image of an illuminated surface (image forming region) 2b of the bulb 2 onto a screen (not shown).

  The light source 4 includes a laser light source 41 of a plurality of colors (three colors in FIG. 1) and a plurality (three in FIG. 1) that collects light beams emitted from the laser light source 41 with one to a plurality of lenses or mirrors. The condensing optical system 42 and a plurality (three in FIG. 1) of optical fibers 43 that guide the light beam emitted from the condensing optical system 42 to the light intensity uniformizing element 6.

  In the light source 4, one condensing optical system 42 and one optical fiber 43 correspond to one laser light source 41. Therefore, the light beam emitted from each laser light source 41 is guided to the light intensity uniformizing element 6 through the condensing optical system 42 and the optical fiber 43 corresponding to each laser light source 41.

  The illumination optical system 7 is an optical system for irradiating the illuminated surface 2b with a light beam, and includes lenses 71 and 72, a first mirror 73, and a second mirror 74. Although FIG. 1 shows the case where the illumination optical system 7 is composed of two lenses and two mirrors, the number of lenses and mirrors is not limited to two and may be any number. . The illumination optical system 7 guides the light beam emitted from the light intensity uniformizing element 6 to the reflective light valve 2 by lenses 71 and 72, a first mirror 73, and a second mirror 74.

  The light intensity uniformizing element 6 has a function of making the light intensity and color unevenness of the light beam emitted from the light source 4 uniform (reducing illumination unevenness and color unevenness). The light intensity uniformizing element 6 includes a light intensity uniformizing portion 61 having a tapered shape in which the area of the cross-sectional shape decreases from the light incident side toward the light exit side, and a cross sectional shape from the light incident side toward the light exit side. The light intensity uniformizing section 62 has a tapered shape with an increasing area. The light intensity uniformizing portions 61 and 62 are formed integrally. In the light intensity uniformizing unit 61, an incident surface (incident end surface) 61a that is an incident port of light faces the optical fiber 43 side, and an outgoing surface (exit end surface) 61b that is an outgoing port of light is an optical intensity uniformizing unit 62. The light intensity uniformizing element 6 is disposed so as to face. Further, the light intensity uniformizing unit 62 has a uniform light intensity such that the incident surface 62a that is the light incident port faces the light intensity uniformizing unit 61 side, and the emission surface 62b that is the light emission port faces the illumination optical system 7. Arranged in the activating element 6. The entrance surface 61a, the exit surface 61b, the entrance surface 62a, and the exit surface 62b are surfaces perpendicular to the optical axis 1a.

  The light intensity uniformizing portions 61 and 62 are elements made of a transparent material such as glass or resin. The light intensity equalizing portions 61 and 62 are polygonal columnar rods (columnar members having a polygonal cross-sectional shape) configured such that the inner side of the side wall is a total reflection surface, or cylindrical with the light reflection surface inside. The combined cross-sectional shape includes a polygonal light pipe (tubular member) and the like. When the light intensity uniformizing sections 61 and 62 are polygonal rods, the light intensity uniformizing sections 61 and 62 reflect light multiple times using the total reflection action between the transparent material and the air interface. Later, light is emitted from the emission ends (emission surfaces 61b and 62b). In addition, when the light intensity uniformizing units 61 and 62 are polygonal light pipes, the light intensity uniformizing units 61 and 62 reflect light multiple times using the reflecting action of the surface mirror facing inward. After that, light is emitted from the emission surfaces 61b and 62b.

  If the light intensity uniformizing element 6 secures an appropriate length in the traveling direction of the light beam, the light reflected therein a plurality of times is superimposed and irradiated in the vicinity of the exit surface 62b of the light intensity uniformizing element 6 so that the light A substantially uniform intensity distribution is obtained in the vicinity of the emission surface 62b of the intensity uniformizing element 6. The outgoing light from the outgoing surface 62b having a substantially uniform intensity distribution is guided to the reflective light valve 2 by the illumination optical system 7, and illuminates the illuminated surface 2b of the reflective light valve 2.

  The reflective light valve 2 is an element that reflects an incident light beam from the illumination optical system 7 toward the projection optical system 3 (reflects in the direction of the optical axis 1a). The projection optical system 3 is reflected by the reflective light valve 2. The projected light beam (image) is projected onto the screen.

  Next, light propagation in the optical path within the illumination optical system 7 will be described. FIG. 2 is a diagram for explaining light propagation in the illumination optical system. FIG. 2 conceptually shows the operation of the illumination optical system 7 and the relationship between the light intensity uniformizing element 6 and the reflective light valve 2.

  In the present embodiment, the illumination optical system 7 is configured such that the exit surface 62b of the light intensity uniformizing unit 62 and the illuminated surface 2b of the reflective light valve 2 are in an optically conjugate relationship. In other words, the cross-sectional shape of the exit surface 62b of the light intensity uniformizing unit 62 arranged closest to the illumination optical system 7 among the plurality of light intensity uniformizing units is defined as the shape of the illuminated surface 2b of the reflective light valve 2. It is formed in a substantially similar shape. The reflection type light valve 2 is, for example, a reflection type light modulation element such as a DMD (digital micromirror device) (registered trademark) element, a reflection type liquid crystal display element or a transmission type liquid crystal display element. In the present embodiment, a case where the reflective light valve 2 is a DMD (registered trademark) element will be described.

  For example, the area of the exit surface 62b of the light intensity uniformizing element 6 is S1, and the area of the illuminated surface 2b of the reflective light valve 2 is S2. As shown in FIG. 2, when the solid angle of the light beam emitted from the light intensity uniformizing element 6 is Ω1, and the solid angle of the incident light beam on the illuminated surface 2b of the reflective light valve 2 is Ω2, the light beam is emitted. The product of the area and solid angle of each of the surface 62b and the illuminated surface 2b is kept constant. That is, S1 × Ω1 = S2 × Ω2 is established.

  The reflection type light valve 2 is a planar arrangement of a large number (for example, several hundred thousand) of movable micromirrors corresponding to each pixel, and the inclination angle (tilt) of each micromirror is set according to pixel information. It is configured to change. The reflection type light valve 2 has a predetermined angle α in a certain direction with respect to the reference surface when the surface on which the micromirrors are arranged (the surface of the substrate on which the micromirrors are formed) is used as the reference surface. By tilting by (for example, 12 degrees), the incident light beam is reflected toward the projection optical system 3. The light beam incident on the projection optical system 3 is used for image projection on a screen (not shown). The reflective light valve 2 reflects an incident light beam toward a light absorbing plate (not shown) provided with a micromirror as a reference surface. In other words, the reflective light valve 2 reflects the incident light beam toward the light absorbing plate by tilting the micromirror with respect to the reference plane in a certain direction by a predetermined angle β (for example, minus 12 degrees). The light beam incident on the light absorbing plate is not used for image projection on the screen.

  Next, a detailed operation of the light intensity uniformizing element 6 according to the present embodiment will be described. FIG. 3 is a cross-sectional view of the light intensity uniformizing element. FIG. 3 shows a cross-sectional configuration when the light intensity equalizing element 6 is cut along a plane including the optical axis 1a (straight line). The light intensity uniformizing element 6 is configured by joining light intensity uniformizing sections 61 and 62 for uniforming the intensity distribution of light beams in the direction of the optical axis 1a. Further, the light intensity homogenizers 61 and 62 use light intensity homogenizers 61 and 62 having different shapes so that the intensity distribution uniformity characteristic of the light flux changes at the joint surface of the light intensity homogenizers 61 and 62. ing.

  When the light intensity uniformizing portion 61 is cut along a plane perpendicular to the optical axis 1a, the cross-sectional shape on the incident surface side (incident surface 61a) and the cross-sectional shape on the light emitting surface side (exit surface 61b) of the light intensity uniformizing portion 61. Are respectively a rectangle of 2.5 mm × 1.35 mm and a rectangle of 1 mm × 0.63 mm. Further, when the light intensity uniformizing section 62 is cut along a plane perpendicular to the optical axis 1a, the cross section of the light intensity uniformizing section 62 on the incident surface side (incident surface 62a) and the cross section of the light emitting surface side (exit surface). 62b) are rectangles of 1 × 0.63 mm and 5.8 × 3.7 mm, respectively. Further, the light intensity uniformizing section 61 and the light intensity uniformizing section 62 have a length in the direction of the optical axis 1a of 40 mm and 30 mm, respectively. The light intensity uniformizing portions 61 and 62 are both formed of glass rods having a refractive index of 1.52. In FIG. 3, the light beams 64A and 64B passing through the light intensity uniformizing element 6 are shown as the outermost light beams of a light beam having an F value of 0.88 (26 degrees of divergence angle on one side).

  In FIG. 3, the number of reflections of the light beam 64A and the light beam 64B in the light intensity uniformizing element 6 is 21 times in the light intensity uniformizing unit 61 and 6 times in the light intensity uniformizing unit 62. The total of the element 6 is 27 times.

  Here, a case where the light intensity uniformizing element 6 is formed in a conventional single shape will be described. FIG. 4 is a cross-sectional view of a conventional light intensity uniformizing element. The conventional light intensity equalizing element 106 has a rectangular shape when both a cross section cut along a plane including the optical axis 1a and a cross section cut along a plane perpendicular to the optical axis 1a. The light intensity uniformizing element 106 has a cross-sectional area (5.8 mm × 3.7 mm) having the same shape as the light intensity uniformizing part 62, and the length in the direction of the optical axis 1 a is equal to that of the light intensity uniformizing part 61. It is assumed that the total length is 70 mm. In this case, the number of reflections of the light beam 164A and the light beam 164B passing through the light intensity uniformizing element 106 within the light intensity uniformizing element 106 is six. Thus, the conventional light intensity uniformizing element 106 has a sufficiently reduced number of reflections compared to the light intensity uniformizing element 6 of this embodiment (the light intensity uniformizing element 6 in FIG. 3). A uniform light intensity uniforming effect cannot be obtained. In order to give a sufficient light intensity uniforming effect to the conventional light intensity uniformizing element 106, the length of the light intensity uniformizing element 106 needs to be four times (280 mm) that of the light intensity uniformizing element 6. As a result, the layout of the light intensity uniformizing element 106 is greatly affected.

  The cross-sectional shapes of the emission surface 62b of the light intensity uniformizing unit 62 shown in FIG. 3 and the emission surface 106b of the light intensity uniformizing element 106 shown in FIG. 4 are, for example, 5.8 mm × 3.7 mm. The size of the cross-sectional shape is determined by the optical relationship between the reflective light valve 2 and the light intensity uniformizing elements 6 and 106. The same illumination optical system 7 is provided to the light intensity uniformizing elements 6 and 106. This size is determined as long as it is used.

  If the number of reflections of the light beams 64A and 64B in the light intensity uniformizing element 6 is small, the light intensity of the light beam emitted from the light intensity uniformizing element 6 is not sufficiently uniformized. Further, in the present embodiment, a laser light source 41 of three primary colors is employed in the projection display device 1 and a configuration in which the light intensity equalizing element 6 is guided using an optical fiber 43 is employed. Here, an arrangement example of the optical fiber 43 on the incident surface 61a of the light intensity uniformizing element 6 will be described. FIG. 5 is a diagram for explaining an arrangement example of optical fibers. FIG. 5 shows a cross-sectional view (incident surface 61a) when the optical fiber 43 is cut along a plane perpendicular to the optical path.

  For example, a total of three optical fibers 43R, a green optical fiber 43G, and a blue optical fiber 43B are used as the optical fibers 43 that guide the light beams emitted from the red, green, and blue laser light sources 41. . In this case, on the incident surface 61a of the light intensity uniformizing element 6, for example, as shown in FIG. 5, the red optical fiber 43R, the green optical fiber 43G, A blue optical fiber 43B is disposed. The light intensity uniformizing element 6 is required to mix three color light fluxes and to uniformize the light intensity of the light flux. Therefore, the light intensity uniformizing element 6 can make the light intensity even more uniform than an optical system using a conventional lamp light source. In many cases, an effect is required.

  In the projection display device 1 of the present embodiment, even when the three primary color laser light sources 41 are employed as the light source, the light intensity uniformizing element 6 is configured by the two light intensity uniformizing sections 61 and 62. Therefore, the effect of uniforming the light intensity can be easily increased. In other words, even when it is necessary to enhance the light intensity uniforming effect in the light intensity uniformizing element 6 as compared with the case where a conventional lamp light source is adopted as the light source, the light intensity uniforming effect can be easily enhanced. Is possible.

  In FIG. 3, the case where the light intensity uniformizing unit 61 and the light intensity uniformizing unit 62 in the light intensity uniformizing element 6 are configured by glass rods having a refractive index of 1.52 is described. , 62 may have other configurations.

  FIG. 6 is a diagram showing another configuration example of the light intensity uniformizing element. In the light intensity uniformizing element 6 of FIG. 6, the light intensity uniformizing part 61 and the light intensity uniformizing part 62 in the light intensity uniformizing element 6 are formed in a cylindrical shape with the light reflection surface (reflection surface of the surface mirror) inside. It consists of a combined light pipe.

  When the light intensity uniformizing section 61 and the light intensity uniformizing section 62 are configured by light pipes, the reflection effect of the surface mirror facing inward is used while preserving the incident angle to the incident surface 61a of the light intensity uniformizing element 6. As a result, the light intensity uniformizing portions 61 and 62 are propagated. Accordingly, the light intensity uniformizing element 6 can be configured to be shorter than the light intensity uniformizing sections 61 and 62 of the glass rod as shown in FIG.

  In FIG. 6, as in FIG. 3, the cross-sectional shape (incident surface 61 a) on the incident surface side of the light intensity uniformizing portion 61 and the emission when the light intensity uniformizing portion 61 is cut along a plane perpendicular to the optical axis 1 a. In this example, the cross-sectional shape (outgoing surface 61b) on the surface side is configured by a rectangle of 2.5 mm × 1.35 mm and a rectangle of 1 mm × 0.63 mm, respectively. Further, when the light intensity uniformizing section 62 is cut along a plane perpendicular to the optical axis 1a, the cross section of the light intensity uniformizing section 62 on the incident surface side (incident surface 62a) and the cross section of the light emitting surface side (exit surface). 62b) are 1 mm × 0.63 mm and 5.8 mm × 3.7 mm rectangles, respectively. Also in FIG. 6, similarly to FIG. 3, the light beams 64A and 64B passing through the light intensity uniformizing element 6 are shown as outermost light beams having an F value of 0.88 (26 degrees of divergence angle on one side). .

  Further, the light intensity uniformizing section 61 and the light intensity uniformizing section 62 shown in FIG. 6 have lengths in the direction of the optical axis 1a of 20 mm and 10 mm, respectively. In FIG. 6, the number of reflections of the light beam 64A and the light beam 64B in the light intensity uniformizing element 6 is 23 times in the light intensity uniformizing unit 61 and 4 times in the light intensity uniformizing unit 62. The total of the element 6 is 27 times.

  Thus, when the light intensity uniformizing element 6 is formed of a glass rod, it is reflected 27 times with an optical path length of 70 mm, whereas when the light intensity uniformizing element 6 is formed of a light pipe, the optical path length is 30 mm. Reflects 27 times. Therefore, when the light intensity uniformizing element 6 is constituted by a light pipe, the reflection can be performed 27 times with a shorter optical path length than when the light intensity uniformizing element 6 is constituted by a glass rod. For this reason, when the light intensity equalizing element 6 is formed of a light pipe, the light intensity uniformizing element 6 is equivalent to the light intensity uniformization with a shorter optical path length than when the light intensity uniformizing element 6 is formed of a glass rod. .

  When the light intensity uniformizing element 6 is constituted by a glass rod or a resin rod that reflects using the total reflection action between the material of the light intensity uniformizing element 6 and the air interface, the loss of light amount due to reflection from the air interface is Therefore, it is possible to increase the light use efficiency.

  Further, when the light intensity uniformizing element 6 is configured by a light pipe that uses the reflection action of the surface mirror facing inward, the optical path length is shortened and the light intensity uniformizing section 61 and the light intensity uniformizing section 62 are coupled. In addition, cooling and holding becomes easy.

  Further, in the present embodiment, an example in which the light intensity uniformizing element 6 is configured by two of the light intensity uniformizing unit 61 and the light intensity uniformizing unit 62 has been described. FIG. 7, FIG. 8, and FIG. As described above, the light intensity uniformizing element 6 may be composed of three or four or more light intensity uniformizing sections.

  7 to 9 are diagrams illustrating the configuration of a light intensity uniformizing element configured by three light intensity uniformizing units. FIG. 7 is a diagram illustrating a first configuration example in which the light intensity uniformizing element is configured by three light intensity uniformizing units. FIG. 8 illustrates the light intensity uniformizing element having three light intensity uniformizing units. FIG. 9 is a diagram illustrating a third configuration example when the light intensity uniformizing element is configured by three light intensity uniformizing units.

  The light intensity uniformizing element 6 shown in FIGS. 7 to 9 includes three light intensity uniformizing sections 61, 62, and 63. 7 has the same configuration (taper shape) as the light intensity uniformizing unit 61 described with reference to FIG. 3, and the light intensity uniformizing unit 63 includes the light described with reference to FIG. It has the same configuration (taper shape) as the strength uniformizing section 62. Further, the light intensity uniformizing section 62 here has the same configuration (side surface parallel to the optical axis 1a) as the light intensity uniformizing element 106 described in FIG.

  The light intensity uniformizing section 61 is disposed in the light intensity uniformizing element 6 so that the incident surface 61a faces the optical fiber 43 side and the emission surface 61b faces the light intensity uniformizing section 62. The light intensity uniformizing section 62 is disposed in the light intensity uniformizing element 6 so that the incident surface 62a faces the light intensity uniformizing section 61 and the exit surface 62b faces the light intensity uniformizing section 63. . Further, the light intensity uniformizing section 63 is disposed in the light intensity uniformizing element 6 so that the incident surface 63a faces the light intensity uniformizing section 62 side and the emission surface 63b faces the illumination optical system 7. The exit surface 61b has the same shape as the entrance surface 62a, and the exit surface 62b has the same shape as the entrance surface 63a.

  The light intensity uniformizing element 6 in FIG. 7 is a member (light intensity uniformizing section 61) having a tapered shape in which the area of the cross-sectional shape decreases from the incident side to the output side, and a corner having a constant cross-sectional area. It is constituted by a columnar parallel member (light intensity uniformizing portion 62) and a member (light intensity uniformizing portion 63) having a tapered shape in which the area of the cross-sectional shape increases. Since the light intensity uniformizing part 62 having a side surface parallel to the optical axis 1a direction is provided in the central part of the light intensity uniformizing element 6 (between the light intensity uniformizing part 61 and the light intensity uniformizing part 63). The reflection angle of the propagating light beam changed by the light intensity uniformizing unit 61 can be maintained without changing the size of the cross-sectional shape. As a result, the light intensity uniformizing unit 62 can increase the number of reflections of light rays while keeping the cross-sectional shape of the light intensity uniformizing element 6 to an arbitrary size (the same size as the emission surface 61b).

  The light intensity uniformizing unit 61 in FIG. 8 has the same configuration as the light intensity uniformizing unit 61 described in FIG. 3, and the light intensity uniformizing unit 62 is the light intensity uniformizing unit described in FIG. The configuration is the same as 62. The light intensity uniformizing unit 63 here has the same configuration as the light intensity uniformizing unit 106 described with reference to FIG.

  Further, the light intensity uniformizing sections 61 to 63 of the light intensity uniformizing element 6 shown in FIG. 8 are arranged at the same positions as the light intensity uniformizing sections 61 to 63 of the light intensity uniformizing element 6 shown in FIG. Has been. That is, the light intensity uniformizing sections 61 to 63 are disposed in the light intensity uniformizing element 6 so that the incident surfaces 61a to 63a face the optical fiber 43 side and the emission surfaces 61b to 63b face the illumination optical system 7 side. ing. The exit surface 61b has the same shape as the entrance surface 62a, and the exit surface 62b has the same shape as the entrance surface 63a.

  The light intensity uniformizing element 6 in FIG. 8 is a member (light intensity uniformizing section 61) having a tapered shape in which the cross-sectional area decreases from the incident side to the outgoing side, and a tapered shape in which the cross-sectional area increases. And a prismatic parallel member (light intensity equalizing portion 63) having a constant cross-sectional area. Since the light intensity uniformizing section 63 having a side surface parallel to the optical axis 1a direction is provided in the vicinity of the light beam emitting end of the light intensity uniformizing element 6 (on the exit surface 62b side), the light intensity uniformizing section 61, The reflection angle of the propagating light beam changed by 62 can be maintained without changing the size of the cross-sectional shape. Thereby, a light beam (light beam) having a larger emission angle is emitted from the light intensity uniformizing unit 63 than when light beams are emitted from the light intensity uniformizing units 61 and 62 (light intensity uniformizing element 6 in FIG. 3). Is possible.

  9 has the same configuration as the light intensity uniformizing unit 106 described with reference to FIG. 4, and the light intensity uniformizing unit 62 has the same light intensity described with reference to FIG. The configuration is the same as that of the conversion unit 62.

  Further, the light intensity uniformizing sections 61 to 63 of the light intensity uniformizing element 6 shown in FIG. 9 are arranged at the same positions as the light intensity uniformizing sections 61 to 63 of the light intensity uniformizing element 6 shown in FIG. Has been. That is, the light intensity uniformizing sections 61 to 63 are disposed in the light intensity uniformizing element 6 so that the incident surfaces 61a to 63a face the optical fiber 43 side and the emission surfaces 61b to 63b face the illumination optical system 7 side. ing. The exit surface 61b has the same shape as the entrance surface 62a, and the exit surface 62b has the same shape as the entrance surface 63a.

  The light intensity equalizing element 6 in FIG. 9 is a prismatic parallel member (light intensity equalizing portion 61) having a constant cross-sectional area from the incident side to the output side, and a tapered shape in which the cross-sectional area increases. And a prismatic parallel member (light intensity equalizing portion 63) having a constant cross-sectional area. As described above, the light intensity uniformizing element 6 in FIG. 9 has a cross-sectional area between the light intensity uniformizing sections 61 and 63 when combining the single light intensity uniformizing sections 61 and 63 having different cross-sectional shapes. A light intensity uniformizing section 62 having a tapered shape in which the light intensity increases is disposed. Thereby, the spread angle of the light beam emitted from the light intensity uniformizing element 6 can be adjusted. Further, the light beam can be efficiently propagated in the light intensity uniformizing element 6.

  7-9, each light intensity equalizing part 61-63 may be comprised with a glass rod, may be comprised with a light pipe, a glass rod, and light You may comprise combining a pipe. The lengths of the light intensity uniformizing units 61 to 63 are not limited to the above-described configuration example, but the light intensity uniforming effect (light intensity uniformization degree) required for the projection display apparatus 1 and the layout It is determined according to constraints or costs. Therefore, the cross-sectional shape of the light intensity uniformizing portion (the light intensity uniformizing portion 62 in FIGS. 3 and 6 and the light intensity uniformizing portion 63 in FIGS. 7 and 8) of the light intensity uniformizing element 6 on the illumination optical system 7 side. Is determined from the performance of the reflective light valve 2 and the illumination optical system 7, but other cross-sectional shapes (for example, the light intensity uniformizing portion 61 in FIGS. 3, 6, and 7 and the light intensity uniformizing in FIG. 8). The units 61 and 62) may be determined in view of the light intensity uniformization performance required for the projection display device 1, the arrangement of the optical fiber 43, and the like.

  Further, either one of the light intensity uniformizing units 61 and 62 shown in FIG. 3 may be configured by a light pipe, or one of the light intensity uniformizing units 61 and 62 shown in FIG. You may comprise with a glass rod. By configuring either one of the light intensity uniformizing sections 61 and 62 with a light pipe, the light intensity uniformizing section 61 and the light intensity uniformizing section 62 can be easily coupled and the optical path length of the light intensity uniformizing element 6 can be obtained. Can be made shorter. Moreover, it becomes possible to keep light utilization efficiency favorable by comprising either one of the light intensity equalization parts 61 and 62 with a glass rod.

  In this embodiment, the case where the laser light source 41 is used as the light source 4 (multi-primary light source) of the projection display device 1 has been described. However, a light-emitting diode may be used as the multi-primary light source. Even in this case, the same effect as when the laser light source 41 is used as the light source 4 can be obtained.

  In the present embodiment, as described with reference to FIGS. 3 and 6, when the light intensity uniformizing element 6 is configured by the two light intensity uniformizing sections 61 and 62, each light intensity uniformizing section 61, Although the case where both 62 have a tapered shape has been described, the shape of only one of the light intensity uniformizing portions 61 and 62 may be a tapered shape, and the other shape may be a prismatic shape shown in FIG. . Further, even when the light intensity uniformizing element 6 is constituted by three or more light intensity uniformizing parts, the light intensity uniformizing element 6 may have at least one light intensity uniformizing part configured in a tapered shape. Good.

  As described above, according to the first embodiment, the light intensity uniformizing element 6 is composed of a plurality of light intensity uniformizing sections (light intensity uniformizing sections 61 and 62 and light intensity uniformizing sections 61 to 63). It is possible to enhance the effect of uniforming light intensity and color unevenness with a compact configuration. Therefore, even in an optical system that employs a multi-primary light source, it is possible to improve the uniformity of the illuminance distribution (of light intensity and color unevenness) with a small configuration.

  In addition, since the plurality of light intensity equalizing portions in the light intensity equalizing element 6 are configured in different shapes, the light intensity equalizing element 6 is more compact than the case where the light intensity equalizing elements 6 having the same shape are configured. With the configuration, it is possible to enhance the effect of uniforming light intensity and color unevenness.

  Further, since at least one light intensity uniformizing portion of the light intensity uniformizing element 6 has a tapered shape in which the cross-sectional area continuously decreases or increases from the light incident side to the light emitting side, the light intensity uniformization is performed. The reflection angle when light propagates through the element 6 or the angle of the light beam when light exits from the light intensity uniformizing element 6 can be changed. Therefore, even when a multi-primary light source such as a laser light source or an LED light source is adopted as the light source, the uniformity of the illuminance distribution can be improved with a compact configuration.

  Further, when the light intensity uniformizing element 6 is configured such that at least one light intensity uniformizing part of the light intensity uniformizing element 6 is a tubular member and the light beam is reflected by the inner surface thereof, The coupling, cooling, and holding are facilitated, and the optical path length of the light intensity uniformizing element 6 can be shortened, so that the optical system can be configured compactly.

  Further, since at least one light intensity uniformizing portion of the light intensity uniformizing element 6 is formed of a polygonal columnar member made of a transparent material, the light intensity uniformizing element 6 can be easily designed and the light use efficiency can be increased. It becomes. In addition, since the light intensity uniformizing element 6 is formed by integrating a plurality of light intensity uniformizing parts, the light intensity uniformizing element 6 can be obtained at low cost.

  In addition, since the cross-sectional shape of the light intensity uniformizing portion disposed closest to the illumination optical system 7 among the plurality of light intensity uniformizing portions is substantially similar to the shape of the illuminated surface 2b of the reflective light valve 2. It becomes possible to construct an optical system with high light utilization efficiency and good illuminance distribution.

  Further, since the light source is composed of the laser light source 41, a bright optical system having a long life and good color reproducibility can be constructed. In addition, since the light beam emitted from the light source is guided to the light intensity uniformizing element 6 using the optical fiber 43, it is possible to wait for flexibility in the arrangement of the optical system and the light beam in the optical system. Can be improved.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, white light is used as the light source and the area of the incident end face of the light intensity uniformizing element is configured to be large. Specifically, the incident end face of the light intensity equalizing element is set to an incident face 91a having a larger area than the incident face 61a.

  FIG. 10 is a diagram showing a schematic configuration of the optical system of the projection display apparatus according to Embodiment 2 of the present invention. Of the constituent elements in FIG. 10, constituent elements that achieve the same functions as those of the projection display apparatus 1 of the first embodiment shown in FIG. 1 are given the same numbers, and redundant descriptions are omitted.

  A projection display device 1 according to Embodiment 2 includes a lamp light source 8, a light intensity uniformizing element 9, an illumination optical system 7, a reflective light valve (reflective light modulation element) 2, and a projection optical system 3. And have.

  The lamp light source 8 includes a light emitter 8a that emits white light and an ellipsoidal mirror 8b provided around the light emitter 8a. The ellipsoidal mirror 8b reflects the light beam irradiated from the first focal point corresponding to the first center of the ellipse and converges it to the second focal point corresponding to the second center of the ellipse. The light emitter 8a is installed in the vicinity of the first focal point of the ellipsoidal mirror 8b, and the light beam emitted from the light emitter 8a is converged in the vicinity of the second focal point of the ellipsoidal mirror 8b.

  The light beam condensed near the second focal point of the ellipsoidal mirror 8b is guided so as to be condensed on the incident surface 91a of the light intensity equalizing element 9 disposed near the second focal point of the ellipsoidal mirror 8b. The light intensity equalizing element 9 has a function of equalizing the light intensity and color unevenness of the light beam emitted from the lamp light source 8 as in the light intensity equalizing element 6 of the first embodiment. The light intensity uniformizing element 9 includes a light intensity uniformizing section 91 having a tapered shape in which the area of the cross-sectional shape decreases from the light incident side to the light emission side, and from the light incident side to the light emission side. The light intensity uniformizing unit 92 has a tapered shape with an increased cross-sectional area. The light intensity uniformizing portions 91 and 92 are formed integrally, for example. In the light intensity uniformizing section 91, an incident surface (incident end face) 91 a that is a light incident port faces the lamp light source 8 side, and an exit surface (emitted end face) 91 b that is a light exit opening is a light intensity uniformizing section 92. The light intensity uniformizing element 9 is disposed so as to face. Further, the light intensity uniformizing unit 92 has a uniform light intensity so that the incident surface 92a that is the light incident port faces the light intensity uniformizing unit 91 side, and the emission surface 92b that is the light emission port faces the illumination optical system 7. Arranged in the activating element 9. The entrance surface 91a, the exit surface 91b, the entrance surface 92a, and the exit surface 92b are surfaces perpendicular to the optical axis 1a.

  The light intensity uniformizing sections 91 and 92 have the same configuration as the light intensity uniformizing sections 61 and 62 described in the first embodiment, and include a polygonal columnar glass rod or a light pipe. ing. The configuration subsequent to the light intensity equalizing element 9 is the same as that of the projection display device 1 according to the first embodiment, and the description thereof is omitted here.

  When the lamp light source 8 is used as the light source of the projection display device 1, the distribution of the light flux on the incident end face (incident surface 61a of the first embodiment) of the light intensity equalizing element 9 is as shown in the upper part of FIG. become. Specifically, a light beam having a high density is distributed at the center of the incident surface 61a, and a light velocity having a low density is distributed concentrically as the outer periphery is reached. Since the light flux distributed concentrically has a larger area distribution than the incident surface 61a, a loss occurs when the light flux enters the light intensity uniformizing element 6. Therefore, in the present embodiment, the incident end face (incident surface 91a) of the light intensity uniformizing element 9 is configured with a large area. For example, as shown in the lower part of FIG. 11, the incident surface 91a is configured with an area larger than the distribution area of the light flux on the incident surface 91a. In other words, the incident surface 91a is a surface having a size capable of entering all the light beams sent from the lamp light source 8 to the light intensity uniformizing element 9. As a result, all the light beams distributed concentrically can be incident on the incident surface 91a.

  As described above, according to the second embodiment, by increasing the incident cross-sectional shape of the light intensity uniformizing section 91, even when a light source having a large intensity distribution area of the light beam such as the lamp light source 8 is used, The light source can be efficiently guided into the light intensity uniformizing element 9. Further, as in the first embodiment, the reflection of the light beam propagating in the light intensity uniformizing element 9 by the light intensity uniformizing section 91 having a tapered shape in which the area of the cross-sectional shape decreases from the incident side to the output side. The angle can be changed. Further, the angle of the light beam emitted from the light intensity uniformizing element 9 can be adjusted by the light intensity uniformizing section 92 having a tapered shape in which the area of the cross-sectional shape increases from the incident side to the output side.

  As described above, the projection display device according to the present invention is suitable for projecting and displaying an image on a screen.

2 is a diagram illustrating a schematic configuration of an optical system of the projection display apparatus according to Embodiment 1. FIG. It is a figure for demonstrating the light propagation in an illumination optical system. It is sectional drawing of a light intensity equalization element. It is sectional drawing of the conventional light intensity equalization element. It is a figure for demonstrating the example of arrangement | positioning of an optical fiber. It is a figure which shows the other structural example of a light intensity equalization element. It is a figure which shows the 1st structural example at the time of comprising a light intensity equalization element by three light intensity equalization parts. It is a figure which shows the 2nd structural example at the time of comprising a light intensity equalization element by three light intensity equalization parts. It is a figure which shows the 3rd structural example at the time of comprising a light intensity equalization element by three light intensity equalization parts. 6 is a diagram showing a schematic configuration of an optical system of a projection display apparatus according to Embodiment 2. FIG. It is a figure for demonstrating the entrance plane of the light intensity equalization element which concerns on Embodiment 2, and distribution of a light beam.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projection display apparatus 1a Optical axis 2 Reflection type light valve 2b Illuminated surface 3 Projection optical system 4 Light source 6,9 Light intensity equalization element 7 Illumination optical system 8 Lamp light source 8a Luminescent body 8b Ellipsoidal mirror 41 Laser light source 42 Collection Optical optical system 43 Optical fiber 61-63, 91, 92 Light intensity uniformizing part 61a, 62a, 63a, 91a, 92a Incident surface 61b, 62b, 63b, 91b, 92b Emission surface 64A, 64B Light beam

Claims (6)

A projection type having a light source and a light intensity uniformizing element for uniformizing the intensity distribution of the light beam emitted from the light source, and performing projection display of an image using the light beam emitted from the light intensity uniformizing element In the display device,
The light intensity uniformizing element is configured by joining a plurality of light intensity uniformizing sections for uniforming the intensity distribution in the optical axis direction, and at least one of the light intensity uniformizing sections is in the optical axis direction. A projection display device having a tapered shape in which an area of a cross-sectional shape increases or decreases.   The projection display device according to claim 1, wherein the light intensity uniformizing portion having a tapered shape includes a tubular member that reflects a light beam on an inner surface.   3. The projection display device according to claim 1, wherein the light intensity uniformizing portion having the tapered shape includes a transparent polygonal columnar member that reflects a light beam therein. 4.   The projection display device according to claim 1, wherein the light intensity uniformizing element is formed by integrating light intensity uniformizing portions.   The projection display device according to claim 1, wherein the light source emits multi-primary light. The light source is a lamp light source;
6. The incident surface of the light intensity uniformizing element is a surface having a size capable of receiving all light beams transmitted from the lamp light source to the light intensity uniformizing element. A projection display device according to any one of the above.