JP5532772B2 - Projection display - Google Patents

Description

  The present invention relates to a projection display device that projects an image on a screen using a reflective light valve.

  When a rectangular light tunnel is used as a light intensity equalizing element in a conventional projection display device using a reflective light valve, the light beam radiated on the reflective light valve is greatly distorted from the rectangular light. There was a problem that utilization efficiency was lowered. In order to solve this problem, there is one using a wedge-shaped light tunnel provided with a taper (for example, see Patent Document 1). This light tunnel has a tapered portion formed so that the cross-sectional area continuously decreases on the incident surface side, and the exit surface is irradiated onto the reflective light valve by being inclined at a certain angle with respect to the incident surface. The distortion of the illumination area formed by the luminous flux is reduced.

JP 2006-228718 A (paragraphs 0020 to 0031, FIGS. 6 to 7)

  However, in such an optical system, since the shape of the light tunnel is complicated, there is a problem that processing is difficult and the cost is increased.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain a projection display device with low cost and high light utilization efficiency.

A projection display device according to the present invention includes a light source, a light intensity uniformizing element that uniformizes an intensity distribution of a light beam emitted from the light source, and a lens group that collects the light beam emitted from the light intensity uniformizing element. A reflective light valve for forming an image in the image forming area, and an enlarged image formed in the image forming area. A projection optical system for projecting, and a lens that is held in a state of being rotated about a line of intersection between a plane perpendicular to the optical axis of the illumination optical system and a plane parallel to the image forming area of the lens group. The vertex through which the rotation axis passes is set based on the relationship with the position of the stop of the optical system, and the optical axis of the illumination optical system is increased so that the amount of light beam incident on the image forming area from the light intensity uniformizing element is increased. It is characterized by being inclined.

The projection type display apparatus according to the present invention includes a light source, and the light intensity equalizing element for equalizing the intensity distribution of the emitted light beam from a light source, an image forming area, images based on the light beam a reflection type light valve to form an image formation region, and a lens for guiding a light beam emitted from the light intensity equalizing element in the images forming region, a projection optical system for enlarging and projecting the image formed on images forming region the provided, so that the amount of the light beam incident to the light intensity equalizing element or al picture image forming region increases, the lenses, light sources, the light intensity equalizing element, the light of the illumination optical system including a及beauty lenses It is characterized by being held eccentrically with respect to the shaft .

According to the projection display device according to the present invention, the area to be irradiated onto the reflection type light valve of the light beam emitted from the light intensity equalizing element is emitted from the optical axis and lenses of the light beam incident on the lenses For a lens held in a rotated state so as to be smaller than the case where the optical axis of the luminous flux coincides, the vertex through which the rotational axis passes is set based on the relationship with the position of the stop of the illumination optical system Thus, since the lens is tilted with respect to the optical axis of the illumination optical system, it is possible to suppress the distortion of the illumination area at low cost and to improve the light utilization efficiency.

The area to be irradiated on the reflection type light valve of the light beam emitted from the light intensity equalizing element, of the light beam emitted from the optical axis and lenses of the light beam incident to the lenses and the optical axis coincides to be smaller than if you are so held by decentering the lenses at low cost, it is possible to suppress the distortion of the illumination area, the effect that it is possible to improve the light utilization efficiency can be obtained.

It is a figure which shows schematically the structure of the optical system of the conventional projection type display apparatus. It is a perspective view which shows the holding means of the conventional projection display apparatus. It is a figure which shows the output surface of the light uniformizing element in the optical system of the conventional projection display apparatus. It is a figure which shows roughly the to-be-illuminated surface on the DMD element in the optical system of the conventional projection display apparatus, and the actual illumination area | region on a DMD element. It is a figure which shows roughly the axis line at the time of rotating the output surface of the light uniformization element in the optical system of the projection type display apparatus which concerns on this Embodiment 1, and a relay lens. It is a figure which shows the rotating shaft and rotation center of a relay lens in the projection type display apparatus which concerns on this Embodiment 1. FIG. It is a figure which shows the change of the light utilization efficiency when rotating about the relay lens 71 in the optical system of the projection type display apparatus which concerns on this Embodiment 1 centering | focusing on the incident-surface vertex and the output surface vertex. It is a figure which shows the change of the light utilization efficiency when rotating about the relay lens 72 in the optical system of the projection type display apparatus which concerns on this Embodiment 1 by making an entrance plane vertex and an exit surface vertex into a rotation center, respectively. It is a figure which shows the change of the light utilization efficiency when rotating about the relay lens 73 in the optical system of the projection type display apparatus concerning this Embodiment 1 centering on the incident-surface vertex and the output surface vertex, respectively. It is a figure which shows the case where the relay lens 73 is rotated in the optical system of the projection type display apparatus which concerns on this Embodiment 1. FIG. It is a perspective view which shows the holding means of the projection type display apparatus which concerns on this Embodiment 1. FIG. It is a schematic diagram which shows the difference in the shape of the lens holder of the projection display apparatus which concerns on this Embodiment 1, and the conventional projection display apparatus. FIG. 6 is a diagram schematically showing an illuminated surface on the DMD element and an actual illumination area on the DMD element when the relay lens 73 is rotated in the optical system of the projection display apparatus according to Embodiment 1. It is a figure which shows the case where the relay lens 71 is rotated in the optical system of the projection type display apparatus which concerns on this Embodiment 1. FIG. FIG. 6 is a perspective view showing a holding unit of another projection display apparatus according to Embodiment 1. It is a schematic diagram which shows the difference in the shape of the lens holder of the other projection display apparatus which concerns on Embodiment 1, and the conventional projection display apparatus. FIG. 3 is a diagram schematically showing an illuminated surface on the DMD element and an actual illumination area on the DMD element when the relay lens 71 is rotated in the optical system of the projection display apparatus according to Embodiment 1. It is a figure which shows the case where the relay lenses 71 and 73 are rotated in the optical system of the projection type display apparatus which concerns on this Embodiment 1. FIG. FIG. 6 is a perspective view showing a holding unit of another projection display apparatus according to Embodiment 1. FIG. 3 is a diagram schematically showing an illuminated surface on a DMD element and an actual illumination area on the DMD element when relay lenses 71 and 73 are rotated in the optical system of the projection display apparatus according to the first embodiment. . It is a schematic diagram which shows arrangement | positioning of an optical component in case a light beam enters into a DMD element perpendicularly | vertically. It is sectional drawing of the light beam in the position corresponded to a DMD element at the time of making a light beam enter into a DMD element perpendicularly. It is a figure which shows the case where the relay lenses 71 and 73 are decentered in the optical system of the projection type display apparatus which concerns on this Embodiment 2. FIG. It is a figure which shows schematically the moving axis at the time of decentering the output surface of the light uniformizing element and the relay lens in the optical system of the projection type display apparatus which concerns on this Embodiment 2. FIG. It is a figure which shows the eccentric direction of the relay lens in the projection type display apparatus which concerns on this Embodiment 2. FIG. It is a figure which shows the change of the light utilization efficiency when decentering about each of the relay lenses 71, 72, and 73 in the optical system of the projection type display apparatus which concerns on this Embodiment 2. FIG. FIG. 6 is a diagram schematically showing an illuminated surface on a DMD element and an actual illumination area on the DMD element when relay lenses 71 and 73 are decentered in the optical system of the projection display apparatus according to the second embodiment. is there. FIG. 6 is a perspective view showing a holding unit of a projection display apparatus according to Embodiment 2. It is a schematic diagram which shows the difference in the shape of the lens holder of the projection display apparatus which concerns on Embodiment 2, and the conventional projection display apparatus. It is a schematic diagram which shows the difference in the shape of the lens holder of the other projection display apparatus which concerns on Embodiment 2, and the conventional projection display apparatus.

Embodiment 1 FIG.
FIG. 1 is a diagram schematically showing a configuration of a conventional projection display apparatus 10a. As shown in FIG. 1, the conventional projection display apparatus 10 a includes an illumination optical system 1, a DMD element 2 as a reflective light valve, and a surface to be illuminated of the DMD element 2 illuminated by the illumination optical system 1 ( A projection optical system 3 that projects an image in an image forming area 2b onto a screen (not shown). The illumination optical system 1 is an optical system for irradiating the illuminated surface 2b of the DMD element 2 with the light beam emitted from the light emitter 4a. The illumination optical system 1 includes a light source lamp 4, a rotating color filter 5 that passes a light beam in a specific wavelength band among the light beams emitted from the light source lamp 4, and a light beam cross section of the light beam that has passed through the rotating color filter 5. It has a light intensity equalizing element 6 that equalizes the light intensity distribution inside (that is, in a plane orthogonal to the central axis of the light beam), and a relay lens group 7 including relay lenses 71 to 73. The relay lens group 7 guides the emitted light beam from the light intensity uniformizing element 6 to the DMD element 2.

  The light source lamp 4 includes, for example, a light emitter 4a that emits white light by arc discharge between a rod-shaped positive electrode and a negative electrode that are positioned at the approximate center of a substantially spherical glass bulb formed of quartz glass or the like, and the light emission. And an ellipsoidal mirror 4b provided around the body 4a. The ellipsoidal mirror 4b reflects the light beam emitted 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 4a is disposed in the vicinity of the first focal point of the ellipsoidal mirror 4b, and the light beam emitted from the light emitter 4a is converged in the vicinity of the second focal point of the ellipsoidal mirror 4b. The illumination optical axis 1a of the illumination optical system 1 is defined by the axis passing through the first focal point and the second focal point of the ellipsoidal mirror 4b. The light source lamp 4 is not limited to the configuration shown in FIG. 1, and a parabolic mirror may be used instead of the ellipsoidal mirror 4b, for example. In this case, the light beam emitted from the light emitter 4a may be converged by a condenser lens after being substantially parallelized by a parabolic mirror. Further, a concave mirror other than a parabolic mirror can be used instead of the ellipsoidal mirror 4b.

  The rotating color filter 5 is obtained by dividing a disk-shaped member into, for example, a fan shape and forming three filter regions of red, green, and blue, respectively. The three filter regions of red, green, and blue pass only light beams corresponding to the red, green, and blue wavelength bands, respectively. The rotating color filter 5 rotates around an axis 5a that is substantially parallel to the illumination optical axis 1a, and each filter region is located near the second focal point of the ellipsoidal mirror 4b on the illumination optical axis 1a of the light source lamp 4. It is configured as follows. By rotating the rotating color filter 5 in synchronization with the image signal, red light, green light, and blue light are sequentially applied to the DMD element 2 (in a field sequential manner). The axis 5a may have an angle with respect to the illumination optical axis 1a.

  The light intensity uniformizing element 6 has a function of uniforming the light intensity distribution of the light beam that has passed through the rotating color filter 5 in the cross section of the light beam (that is, reducing illuminance unevenness). The light intensity uniformizing element 6 is generally made of a transparent material such as glass or resin, and is a quadrangular columnar rod (that is, a columnar column having a square cross section) that is configured such that the inside of the side wall becomes a total reflection surface. Member), or a pipe (tubular member) having a cross-sectional shape of a quadrilateral that is combined in a cylindrical shape with the light reflecting surface on the inside. When the light intensity equalizing element 6 is a square columnar rod, the light is reflected from a plurality of times using the total reflection action between the transparent material and the air interface, and then emitted from the exit end (exit port). When the light intensity equalizing element 6 is a rectangular pipe, the light is reflected a plurality of times by using the reflecting action of the surface mirror facing inward, and then emitted from the emission port. If the light intensity equalizing element 6 secures an appropriate length in the traveling direction of the light beam, the light reflected inside the light intensity multiple times is superimposed and irradiated in the vicinity of the exit end 6b of the light intensity equalizing element 6 so that the light intensity is uniform. A substantially uniform light intensity distribution is obtained in the vicinity of the emission end 6 b of the activating element 6. The exit end 6b having the substantially uniform light intensity distribution is guided to the DMD element 2 by the relay lens group 7, and the illuminated surface 2b of the DMD element 2 is illuminated.

  The relay lens group 7 includes one or a plurality of relay lenses arranged on the optical path from the light intensity uniformizing element 6 to the DMD element 2, and is emitted from the light intensity uniformizing element 6. The light beam is condensed on the DMD element 2. In the example shown in FIG. 1, the relay lens 71 is composed of three relay lenses 71, 72, and 73.

  The DMD element 2 is a planar arrangement of a large number (for example, several hundred thousand) of movable micromirrors corresponding to each pixel, and changes the tilt angle of each micromirror according to pixel information. It is configured as follows. When the surface on which the micromirrors are arranged (that is, the surface of the substrate on which the micromirrors are formed) is a reference surface, the DMD element 2 has an angle α (for example, 12) in a certain direction with respect to the reference surface. The incident light beam is reflected toward the projection optical system 3, and the light beam incident on the projection optical system 3 is used for image projection on a screen (not shown). The DMD element 2 also tilts the micromirror in the opposite direction with respect to the reference plane by an angle α, so that the incident light beam is applied to a light absorbing plate (not shown) provided at a position away from the projection optical system 3. The light beam reflected and incident on the light absorbing plate is not used for image projection on the screen. In the DMD element 2, an area where a large number of micromirrors are arranged corresponds to an image forming area that is illuminated by the illumination optical system 1 to form an image.

  The projection optical system 3 includes a lens group (not shown) disposed in a lens barrel 3 c, and the incident side opening 3 b is substantially opposed to the DMD element 2. The projection optical axis 3a of the lens group of the projection optical system 3 is parallel to the normal line 2a passing through the center of the illuminated surface (image forming region) 2b of the DMD element 2 and deviated by a predetermined amount δ. That is, the illumination optical axis 1a and the projection optical axis 3a have an angle.

  Next, a structure for holding the relay lenses 71, 72, 73 will be described. FIG. 2 is a diagram showing the relay lenses 71, 72, 73 and holding means for holding these three relay lenses. Components that are the same as or correspond to those in FIG.

  In FIG. 2, lens holders 181, 182, and 183 are integrally formed on the base portion 8 by magnesium die casting or the like. The lens holder 181 has a mounting groove 181a having a shape corresponding to and engaging with the edge thickness portion (edge) 71b of the relay lens 71.

  The cover 191 is a plastic cover in which a holding groove 191 a having a shape corresponding to the edge thickness portion of the relay lens 71 is formed. By placing the relay lens 71 in the mounting groove 181 a and covering the relay lens 71 with the cover 191, the holding groove 191 a of the cover 191 and the outer shape of the relay lens 71 are engaged, and the relay lens 71 is fixed and held. can do. Thus, the lens holder 181 and the cover 191 constitute a holding unit that holds the relay lens 71.

  The lens holder 182 has a mounting groove 182a having a shape corresponding to and engaged with the edge thickness portion (edge) 72b of the relay lens 72. The cover 192 is a plastic cover in which a holding groove 192 a having a shape corresponding to the edge thickness portion of the relay lens 72 is formed. By placing the relay lens 72 in the mounting groove 182a and covering the relay lens 72 with the cover 192, the holding groove 192a of the cover 192 and the outer shape of the relay lens 72 are engaged, and the relay lens 72 is fixed and held. can do. Thus, the lens holder 182 and the cover 192 constitute a holding portion that holds the relay lens 72.

  The lens holder 183 has an engraved mounting groove 183a that is engaged with the edge thickness portion (edge) 73b of the relay lens 73. The cover 193 is a plastic cover in which a holding groove 193 a having a shape corresponding to the edge thickness portion of the relay lens 73 is formed. By mounting the relay lens 73 in the mounting groove 183a and covering the relay lens 73 with the cover 193, the holding groove 193a of the cover 193 and the outer shape of the relay lens 73 are engaged, and the relay lens 73 is fixed and held. can do. Thus, the lens holder 183 and the cover 193 constitute a holding unit that holds the relay lens 73.

  In a general illumination optical system (an illumination optical system corresponding to the illumination optical system 1 in FIG. 1), the cross-sectional shape of the light intensity uniformizing element is emitted from an incident end (an incident end corresponding to the incident end 6a in FIG. 1). It is constant up to the end (the output end corresponding to the output end 6b in FIG. 1), and is formed in a rectangle similar to the illuminated surface 2b of the DMD element 2. FIG. 3 shows the exit surface 6 b of the light intensity uniformizing element 6. In FIG. 3, points A1, B1, C1, and D1 are the four corners (four corners) of the emission surface 6b when viewed from the DMD element 2 side toward the emission end of the light intensity uniformizing element 6. The relay lens group 7 is arranged perpendicular to the optical axis 1a. Further, in the illumination optical system 1 using the DMD element 2, as shown in FIG. 1, the normal direction perpendicular to the illuminated surface 2b of the DMD element 2 from the relay lens 73 (the direction of the axis 2a in FIG. 1). In this case, the actual illumination area (actual illumination area) on the illuminated surface 2b of the DMD element 2 is distorted and not rectangular.

  As shown in FIG. 4, the actual illumination region 2 c on the DMD element 2 using the light intensity uniformizing element 6 has a distorted shape as compared with the shape (rectangular shape) of the illuminated surface 2 b of the DMD element 2. . If the area outside the illuminated surface 2b (hereinafter referred to as the illumination margin) is larger than the illuminated surface 2b, the illumination light beam is effective in the DMD element 2 (illuminated surface 2b) in the portion other than the illuminated surface 2b. Therefore, there is a problem that the light utilization efficiency is lowered because the projection optical system 3 is not reached.

  The above is the description of the conventional example. Next, features of the projection display apparatus according to Embodiment 1 will be described. In the projection display device according to the first embodiment, the DMD element 2 is held by holding at least one relay lens of the relay lens group 7 in a state of being rotated in a fixed direction, not perpendicular to the optical axis 1a. It is possible to improve the light utilization efficiency by improving the distorted shape of the upper real illumination area 2c.

  Here, the rotation axis and rotation center of the relay lens will be described. FIG. 4 shows four corners (four corners) A2, B2, C2, D2 of the actual illumination region 2c when the illuminated surface 2b of the DMD element 2 is viewed from the projection optical system 3 side. 5 shows four corners of the emission surface 6b (when viewed from the DMD element 2 side toward the emission end of the light intensity equalizing element 6 corresponding to the points A2, B2, C2, and D2 shown in FIG. Four corners) A1, B1, C1, D1 are shown. The points A2, B2, C2, and D2 of the actual illumination region 2c on the DMD element 2 shown in FIG. 4 correspond to the points A1, B1, C1, and D1 of the exit surface 6b of the light intensity uniformizing element 6, respectively. The rotation axis of the relay lens to be rotated is set to be parallel to the axis BC passing through the points B1 and C1, as shown in FIG. The center of rotation is the vertex of the entrance surface or the exit surface of each of the relay lenses 71, 72, 73.

  Each of the relay lenses 71, 72, and 73 is rotated around a rotation axis parallel to the axis BC with the entrance surface vertex as the rotation center, and when rotated around the rotation axis parallel to the axis BC with the exit surface vertex as the rotation center. The light utilization efficiency was compared. FIG. 6 shows each rotation axis and rotation direction. θ1 indicates the rotation of the relay lens 71 on the rotation axis parallel to the axis BC with the vertex of the incident surface as the rotation center. θ2 indicates the rotation of the relay lens 71 on the rotation axis parallel to the axis BC with the vertex of the exit surface as the rotation center. θ3 indicates the rotation of the relay lens 72 on the rotation axis parallel to the axis BC with the incident surface vertex as the rotation center. θ4 indicates the rotation of the relay lens 72 about a rotation axis parallel to the axis BC with the exit surface vertex as the rotation center. θ5 indicates the rotation of the relay lens 73 on the rotation axis parallel to the axis BC with the vertex of the incident surface as the rotation center. θ6 indicates the rotation of the relay lens 73 on the rotation axis parallel to the axis BC with the exit surface vertex as the rotation center.

  FIG. 7 shows a simulation result when the relay lens 71 is rotated. The vertical axis represents the relative value of the light utilization efficiency with 100% when no rotation is performed. The light use efficiency here is obtained by dividing the amount of light illuminating the illuminated surface 2 b of the DMD element 2 by the amount of light emitted from the light source lamp 4. The horizontal axis indicates the rotation angle of the relay lens. A curve 61 is obtained when the relay lens 71 is rotated with the incident surface vertex of the relay lens 71 as the rotation center (θ1), and a curve 62 is obtained when the relay lens 71 is rotated with the emission surface vertex of the relay lens 71 as the rotation center. (Θ2) is shown. From the simulation results, when the rotation axis is 2.4 degrees in the positive direction on the rotation axis passing through the vertex of the incident surface of the relay lens 71 and parallel to the axis BC (θ1 = 2.4 degrees), the efficiency is improved by about 0.5%. To do. As described above, the relay lens disposed on the light intensity uniformizing element 6 side from the position of the stop of the illumination optical system 1 like the relay lens 71 rotates about the rotation axis passing through the incident surface vertex of the relay lens. Thus, the light use efficiency can be improved. Note that the position where the principal ray emitted in parallel with the optical axis from the four corners of the exit surface 6 b of the light intensity uniformizing element 6 substantially intersects the optical axis is the stop position of the illumination optical system 1.

  FIG. 8 shows a simulation result when the relay lens 72 is rotated. The vertical axis represents the relative value of the light utilization efficiency with 100% when no rotation is performed. The horizontal axis indicates the rotation angle of the relay lens. A curve 63 indicates a case where the relay lens 72 is rotated about the incident surface vertex of the relay lens 72 as a rotation center (θ3), and a curve 64 indicates a case where the relay lens 72 is rotated about the emission surface vertex of the relay lens 72 as a rotation center. (Θ4) is shown. From the simulation results, the relay lens 72 has an efficiency of about 0.2 when it is rotated 2.4 degrees in the positive direction on the rotation axis parallel to the axis BC with the incident surface vertex as the rotation center (θ3 = 2.4 degrees). % Only. This is because the rotation of the relay lens 72 is in the vicinity of the stop position of the illumination optical system 1 and therefore has little effect on the chief ray, so that the effect of suppressing distortion in the illumination area is low.

  FIG. 9 shows a simulation result when the relay lens 73 is rotated. The vertical axis represents the relative value of the light utilization efficiency with 100% when no rotation is performed. The horizontal axis indicates the rotation angle of the relay lens. A curve 65 is obtained when the relay lens 73 is rotated with the incident surface vertex of the relay lens 73 as the rotation center (θ5), and a curve 66 is obtained when the relay lens 73 is rotated with the emission surface vertex of the relay lens 73 as the rotation center. (Θ6) is shown. From the simulation results, when the vertex of the exit surface of the relay lens 73 is the rotation center and the rotation axis is parallel to the axis BC and is rotated 4.6 degrees in the positive direction (θ6 = 4.6 degrees), the efficiency is about 1.4. %improves. As described above, the relay lens arranged on the DMD element 2 side of the stop position of the illumination optical system 1 like the relay lens 73 is rotated about the rotation axis passing through the exit surface vertex of the relay lens. Light utilization efficiency can be improved.

  From the above, the relay lens 71 or the relay lens 73 is centered on the rotation axis passing through the vertex of the incident surface of the relay lens 71 or the vertex of the output of the relay lens 73, and the surface including the illuminated surface 2b and the relay lens 71 or the relay lens 73. When tilted so that the angle formed with the optical axis is small, the light utilization efficiency is improved. When the magnifications of D1 and A1 at the exit end 6b of the light intensity uniformizing element 6 are different, the distortion is reduced and the light utilization efficiency is improved.

  FIG. 10 is a diagram schematically showing a configuration of a certain projection display device 10b according to the first embodiment, that is, the axis BC (in FIG. 5) with the light emitting surface vertex of the relay lens 73 as the rotation center in the illumination optical system 1. It is a schematic diagram when it is rotated 4.6 degrees in the positive direction in parallel with (shown)) (θ6 = 4.6 degrees). 10, the same or corresponding components as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted.

  FIG. 11 is a diagram showing relay lenses 71, 72, 73 and holding means for holding these three relay lenses in the projection display apparatus 10b shown in FIG. In FIG. 11, the same or corresponding components as those in FIG. FIG. 11 is different from FIG. 2 in that the lens holder 183 is a lens holder 83 and the cover 193 is a cover 93.

  Next, the difference in structure between the lens holder 83 and the lens holder 183 will be described. FIG. 12 is a diagram showing the difference between the shape of the lens holder 83 and the shape of the conventional lens holder 183. 12A is a top view of the lens holder 83 and the relay lens 73, and FIG. 12B is a top view of the conventional lens holder 183 and the relay lens 73.

  The mounting groove 83a of the lens holder 83 is formed so as to be inclined at a predetermined angle θ6 (= 4.6 degrees) around the vertex of the incident surface of the relay lens 73 with respect to the mounting groove 183a of the conventional lens holder 183. Therefore, the relay lens 73 is attached to the lens holder 83 in a state where the optical axis is inclined by θ6 (= 4.6 degrees) as compared with the state where the relay lens 73 is attached to the conventional lens holder 183.

  FIG. 13 shows the relationship between the illuminated surface 2b and the actual illumination areas 2d and 2c. In FIG. 13, an actual illumination area 2d indicates an actual illumination area on the DMD element 2 in the projection display apparatus 10b according to Embodiment 1 shown in FIG. 10, and the actual illumination area 2c is the conventional projection shown in FIG. The actual illumination area on the DMD element 2 in the type display device 10a is shown.

  From FIG. 13, the area of the actual illumination area 2d is smaller than the area of the actual illumination area 2c when the relay lens is not rotated. Although the actual illumination area 2d has moved to the lower right as a whole with respect to the actual illumination area 2c, distortion is reduced by the fact that the point A3 has moved more greatly to the lower right (inside) than other points. The light utilization efficiency is increased by reducing the area of the actual illumination region 2d.

  FIG. 14 is a diagram schematically showing the configuration of another projection display apparatus 10c according to the first embodiment, that is, the axis BC (FIG. 5) with the incident surface vertex of the relay lens 71 as the rotation center in the illumination optical system 1. It is a schematic diagram in the case of being rotated 2.4 degrees in the positive direction in parallel with the angle (θ1 = 2.4 degrees). In FIG. 14, the same or corresponding components as those in FIG.

  FIG. 15 is a diagram showing relay lenses 71, 72, 73 and holding means for holding these three relay lenses in the projection display apparatus 10c shown in FIG. 15 that are the same as or correspond to those in FIG. 2 are assigned the same reference numerals, and descriptions thereof are omitted. FIG. 15 is different from FIG. 2 in that the lens holder 181 is a lens holder 81 and the cover 191 is a cover 91.

  Next, the difference in structure between the lens holder 81 and the lens holder 181 will be described. FIG. 16 is a diagram showing the difference between the shape of the lens holder 83 and the shape of the conventional lens holder 183. 16A is a top view of the lens holder 81 and the relay lens 71, and FIG. 16B is a top view of the conventional lens holder 181 and the relay lens 71.

  The mounting groove 81a of the lens holder 81 is formed to be inclined at a predetermined angle θ1 (= 2.4 degrees) with the incident surface vertex of the relay lens 71 as the center from the mounting groove 181a of the conventional lens holder 181. Therefore, the relay lens 71 is attached to the lens holder 81 in a state where the optical axis is inclined by θ1 (= 2.4 degrees) as compared with the state where the relay lens 71 is attached to the conventional lens holder 181.

  FIG. 17 shows the relationship between the illuminated surface 2b and the actual illumination areas 2d and 2c. In FIG. 17, an actual illumination area 2d indicates the actual illumination area on the DMD element 2 in the projection display apparatus 10c according to Embodiment 1 shown in FIG. 14, and the actual illumination area 2c is the conventional projection shown in FIG. The actual illumination area on the DMD element 2 in the type display device 10a is shown.

  From FIG. 17, the area of the illuminated surface 2d is smaller than the area of the actual illumination area 2c when the relay lens is not rotated. Although the actual illumination area 2d has moved to the upper left as a whole with respect to the actual illumination area 2c, the distortion is reduced by moving the point D3 to the upper left (inner side) larger than the others, and the actual illumination area 2d The light utilization efficiency is increased by reducing the area.

  FIG. 18 is a diagram schematically showing the configuration of another projection display apparatus 10d according to the first embodiment, that is, the axis BC (FIG. 5) with the incident surface vertex of the relay lens 71 as the rotation center in the illumination optical system 1. And rotated in a positive direction by 2.4 degrees (θ1 = 2.4 degrees) parallel to the axis BC (shown in FIG. 5) with the exit surface vertex of the relay lens 73 as the center of rotation. FIG. 6 is a schematic diagram when the angle is rotated 4.6 degrees in the positive direction (θ6 = 4.6 degrees). In FIG. 18, the same or corresponding elements as those in FIG.

  FIG. 19 is a diagram showing relay lenses 71, 72, 73 and holding means for holding these three relay lenses in the projection display apparatus 10d shown in FIG. In FIG. 19, the same or corresponding components as those in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted. FIG. 19 is different from FIG. 2 in that the lens holders 181 and 183 are the lens holders 81 and 83 and the cover 191 and 193 are the covers 91 and 93.

  FIG. 20 shows the relationship between the illuminated surface 2b and the actual illumination areas 2d and 2c. In FIG. 20, an actual illumination area 2d indicates an actual illumination area on the DMD element 2 in the projection display device 10d according to Embodiment 1 shown in FIG. 18, and the actual illumination area 2c is the conventional projection shown in FIG. The actual illumination area on the DMD element 2 in the type display device 10a is shown.

  From FIG. 20, the area of the illuminated surface 2d is smaller than the area of the actual illumination area 2c when the relay lens is not rotated. The point B3 and the point C3 do not substantially move, the point A3 moves to the lower right (inner side), and the point D3 moves to the upper left (inner side), thereby reducing the area of the actual illumination region 2d, thereby improving the light utilization efficiency. Is high. Specifically, it was confirmed that by rotating the relay lens 71 and the relay lens 73, the light utilization efficiency is improved by about 1.5% in the simulation.

  The rotation angle θ is appropriately determined according to the amount of deviation δ between the projection optical axis 3a of the lens group of the projection optical system 3 and the normal 2a passing through the center of the illuminated surface 2b of the DMD element 2 and other parameters. Is desirable.

  As described above, the relay lens 71 is rotated around the vertex of the incident surface of the relay lens 71 and parallel to the axis BC shown in FIG. 5, or the relay lens 73 is rotated around the vertex of the exit surface of the relay lens 73 as the center of rotation. Rotate in parallel with BC, or rotate the relay lens 71 around the vertex of the incident surface of the relay lens 71 and the axis BC, and rotate the relay lens 73 around the vertex of the exit surface of the relay lens 73. By rotating in parallel with the axis BC, the light utilization efficiency can be increased.

  Next, the rotation center of the relay lens will be described with reference to FIGS. 21 and 22. FIG. 21 is a schematic diagram showing the arrangement of optical components when the light beam incident on the DMD element 2 is not tilted as in the present embodiment but is incident vertically. In FIG. 21, the same or corresponding components as those in FIG. 18 are denoted by the same reference numerals, and description thereof is omitted. In FIG. 21, the exit end 6b of the light intensity uniformizing element 6 and the surface of the DMD element 2 are conjugated with each other, and the exit end 6b of the light intensity uniformizing element 6 and the surface of the DMD element 2 are similar. Yes. Therefore, the light beam emitted from the center of the exit end 6b of the light intensity uniformizing element 6 is collected at the center of the DMD element 2, and the light flux emitted from the end of the exit end 6b of the light intensity uniformizing element 6 is condensed to the DMD element 2. Condensed at the end of FIG. 22 is a diagram showing a cross-sectional view of a light beam at a position corresponding to the DMD element 2 in the arrangement shown in FIG. 22A is a cross-sectional view of the light beam when the relay lens is not rotated, FIG. 22B is a cross-sectional view of the light beam when the relay lens 71 is rotated at the entrance surface vertex, and FIG. FIG. 4D is a cross-sectional view of the light beam when rotated at the center of the lens, and FIG. 4D is a cross-sectional view of the light beam when the relay lens 71 is rotated at the vertex of the exit surface. 22A to 22D, the solid line represents the irradiated surface 2b, and the point set near the center of the irradiated surface 2b is a light beam emitted from the center of the emitting end 6b of the light intensity equalizing element 6. , And the point set of the four corners of the irradiated surface 2b represent the condensing spots of the light beams emitted from the four corners of the emitting end 6b of the light intensity uniformizing element 6.

When the relay lens is not rotated, as shown in FIG. 22A, the light spots are uniformly distributed around the center and four corners of the irradiated surface 2b. When the relay lens 71 is rotated at the apex of the incident surface, as shown in FIG. 22B, the condensed spot of the light beam is shifted upward from the center.
When the relay lens 71 is rotated around the lens center, as shown in FIG. 22 (c), since the condensed spot of the light beam hardly moves, the position of the illumination area cannot be changed and the efficiency can be improved. There seems to be nothing. When the relay lens 71 is rotated at the apex of the exit surface, as shown in FIG. 22 (b), the condensed spot of the light beam is shifted downward from the center. In the configuration shown in FIGS. 10, 14, and 18, the light utilization efficiency is increased when the focused spot of the light beam is shifted to the upper side from the center. Therefore, when the relay lens 71 is rotated at the entrance surface vertex, the light utilization is the highest. It turns out that efficiency becomes high.

  From the above, in the relay lens disposed on the light intensity equalizing element 6 side of the stop of the illumination optical system 1 like the relay lens 71, the point on the line segment from the center of the relay lens to the vertex of the incident surface is set. It can be seen that the light utilization efficiency can be improved by using the rotation center, and the highest efficiency can be obtained when the rotation center is the apex of the incident surface. Further, in a relay lens arranged on the DMD element 2 side of the stop position of the illumination optical system 1 like the relay lens 73, a point on a line segment from the center of the relay lens to the vertex of the emission surface is set as the rotation center. It can be seen that the light utilization efficiency can be improved, and that the highest efficiency can be achieved when the center of rotation is the vertex of the exit surface. In any case, the light utilization efficiency can be improved by inclining the relay lens so that the angle formed by the surface including the illuminated surface 2b and the optical axis of the relay lens becomes small.

  According to the projection display apparatus according to the present embodiment, the relay lens is arranged with respect to the optical axis of the illumination optical system 1 so that the amount of the light beam incident on the irradiated surface 2b from the light intensity uniformizing element 6 is increased. By tilting and holding, light utilization efficiency can be increased.

  Furthermore, since it can be realized with a simple structure in which the relay lens is rotated about the axis, it can be realized at low cost.

  Further, in the present embodiment, the relay lens 71 and / or the relay lens 72 is rotated about the intersection line between the surface perpendicular to the optical axis of the illumination optical system 1 and the surface parallel to the irradiated surface 2b as the rotation axis. Therefore, the area of the actual illumination region 2d is smaller than that of the actual illumination region 2c, and the amount of the light beam incident on the illuminated surface 2b from the light intensity uniformizing element 6 is increased. Can be increased.

  This embodiment shows an example, and if the projection display device has a large distortion in the actual illumination region, an effect of further improving the light utilization efficiency can be obtained.

  In this embodiment, the relay optical system is shown by the relay lens group 7, but the same effect can be obtained even if the relay optical system has a mirror. When the relay optical system has a mirror, the positional relationship between the relay lens to be rotated and the DMD element 2 changes depending on the arrangement of the mirror. However, even in this case, the relay lens arranged on the light intensity uniformizing element 6 side with respect to the stop position of the illumination optical system 1 passes through the point on the line segment from the center of the relay lens to the vertex of the incident surface. If the intersecting line between the plane perpendicular to the optical axis of the illumination optical system 1 and the plane parallel to the illuminated surface 2b is inclined, the light utilization efficiency can be increased. Similarly, the relay lens arranged on the illuminated surface 2b side with respect to the position of the stop of the illumination optical system 1 passes through a point on the line segment from the center of the relay lens to the vertex of the exit surface, and the illumination optical system 1 If the intersecting line between the plane perpendicular to the optical axis and the plane parallel to the surface to be illuminated 2b is inclined, the light utilization efficiency can be increased.

Embodiment 2. FIG.
FIG. 23 is a diagram schematically illustrating an example of the configuration of the projection display apparatus 10e according to the second embodiment. In the figure, a projection display device 10e includes an illumination optical system 1, a DMD element 2 as a reflective light valve, and an image of an illuminated surface (image forming area) 2b of the DMD element 2 illuminated by the illumination optical system 1. The projection optical system 3 projects the light onto a screen (not shown), and the illumination optical system 1 passes a light source lamp 4 and a light beam in a specific wavelength band among the light beams emitted from the light source lamp 4. Rotating color filter 5, light intensity equalizing element 6 for equalizing the light intensity distribution of the light beam transmitted through rotating color filter 5 in the cross section of the light beam (that is, in a plane orthogonal to the central light beam), and relay lens 71. Relay lens group 7 including -73. 23 is the same as FIG. 1 except for the relay lens group 7, and the description of the same parts is omitted.

  In the second embodiment, at least one relay lens in the relay lens group 7 is decentered in a certain direction with respect to the optical axis 1a, thereby improving the distorted shape of the actual illumination region on the DMD element 2, Light utilization efficiency can be improved.

  Here, the direction in which the relay lens is decentered will be described. FIG. 24 is a diagram illustrating the emission surface 6 b when viewed from the DMD element 2 side toward the emission end of the light intensity uniformizing element 6. In FIG. 23, the same points as in FIG. The moving axis of the relay lens to be decentered is parallel to the axis AD passing through the points A1 and D1 among the points A1, B1, C1, and D1 at the four corners (four corners) of the emission surface 6b shown in FIG. It was made to become.

  The light utilization efficiency was compared when each of the relay lenses 71, 72, 73 was decentered in the direction parallel to the axis AD. FIG. 25 shows the respective eccentric directions. Reference numeral 71a denotes a lens optical axis connecting the vertex of the entrance surface and the vertex of the exit surface in the relay lens 71. Reference numeral 72a denotes a lens optical axis that connects the entrance surface vertex and the exit surface vertex in the relay lens 72. Reference numeral 73a denotes a lens optical axis connecting the vertex of the entrance surface and the vertex of the exit surface in the relay lens 73.

  FIG. 26 shows a simulation result when each of the relay lenses 71, 72, 73 is eccentric in a direction parallel to the axis AD. The vertical axis shows the relative value of the light utilization efficiency when the eccentricity is not taken as 100%. The horizontal axis indicates the amount of eccentricity of the relay lens. A curve 67 indicates that the relay lens 71 is eccentric in a direction parallel to the axis AD, a curve 68 indicates that the relay lens 72 is eccentric in a direction parallel to the axis AD, and a curve 69 indicates that the relay lens 73 is offset. The case where it decenters in the direction parallel to the axis line AD is shown. From the simulation results, when the relay lens 73 is eccentric by 0.3 mm in the negative direction parallel to the axis AD, the efficiency is improved by about 0.2%. Further, when the relay lens 71 is decentered by 0.2 mm in the positive direction parallel to the axis AD, the efficiency is improved by about 0.1%.

  As described above, the relay lens disposed on the light intensity uniformizing element 6 side of the stop position of the illumination optical system 1 like the relay lens 71 has a surface perpendicular to the optical axis of the illumination optical system 1 and the surface to be illuminated. By using the line of intersection with the surface parallel to 2b as the movement axis and decentering so that the distance from the surface to be illuminated 2b is increased, the light utilization efficiency can be increased. In addition, a relay lens, such as the relay lens 73, disposed on the illuminated surface 2b side of the stop position of the illumination optical system 1 is parallel to the surface perpendicular to the optical axis of the illumination optical system 1 and the illuminated surface 2b. By using the line of intersection with the surface as the movement axis and decentering so that the distance from the surface 2b to be illuminated becomes small, the light utilization efficiency can be increased.

  Next, in the illumination optical system 1, the relay lens 71 is decentered by 0.15 mm in the positive direction parallel to the axis AD (71 s = 0.15 mm), and the relay lens 73 is negative in the direction parallel to the axis AD. A simulation was performed in the case of eccentricity by 0.2 mm in the direction (73 s = −0.2 mm). FIG. 27 shows the relationship between the irradiated surface 2b and the actual illumination areas 2d and 2c. From FIG. 27, the area of the illuminated surface 2d is smaller than the area of the illuminated surface 2c when the lens is not decentered. The point A3, the point B3, and the point C3 do not substantially move, and the point D3 moves to the upper left (inner side), so that the area of 2d is reduced, so that the light use efficiency is increased. Specifically, it has been confirmed that the light utilization efficiency is improved by about 0.3% in calculation by decentering the relay lens 71 and the relay lens 73.

  FIG. 28 is a diagram showing relay lenses 71, 72, 73 and holding means for holding these three relay lenses in the projection display device 10e shown in FIG. 28, the same or corresponding components as those in FIG. 20 are denoted by the same reference numerals and description thereof is omitted. FIG. 28 is different from FIG. 2 in that the lens holders 183 and 181 are the lens holders 103 and 101 and that the covers 193 and 191 are the covers 113 and 111, respectively.

  Next, the difference in structure between the lens holder 101 and the lens holder 181 will be described. FIG. 29 is a diagram showing the difference between the shape of the lens holder 101 and the shape of the conventional lens holder 181. FIG. 29A is a top view of the lens holder 101 and the relay lens 71, and FIG. 29B is a top view of the conventional lens holder 181 and the relay lens 71.

  The mounting groove 101a of the lens holder 101 is formed with a predetermined eccentricity 71s (= 0.15 mm) shifted from the mounting groove 181a of the conventional lens holder 181. Therefore, the relay lens 71 is attached to the lens holder 101 in a state where the optical axis is shifted by 71 s (= 0.15 mm) from the state where the relay lens 71 is attached to the conventional lens holder 181.

  Next, the difference in structure between the lens holder 103 and the lens holder 183 will be described. FIG. 30 is a diagram showing the difference between the shape of the lens holder 103 and the shape of the conventional lens holder 183. 30A is a top view of the lens holder 103 and the relay lens 73, and FIG. 30B is a top view of the conventional lens holder 183 and the relay lens 73.

  The mounting groove 103a of the lens holder 103 is formed with a predetermined eccentricity 73s (= −0.2 mm) shifted from the mounting groove 183a of the conventional lens holder 183. Therefore, the relay lens 73 is attached to the lens holder 103 in a state where the optical axis is shifted by 73 s (= −0.2 mm) from the state in which the relay lens 73 is attached to the conventional lens holder 183.

  Predetermined eccentric amounts 71 s and 73 s in FIGS. 29A and 30A are normal lines 2 a passing through the center of the projection optical axis 3 a of the lens group of the projection optical system 3 and the illuminated surface 2 b of the DMD element 2. It is desirable to determine appropriately according to the magnitude of the deviation amount δ and other parameters.

  As described above, the relay lens 71 is eccentric in the direction parallel to the axis AD, the relay lens 73 is eccentric in the direction parallel to the axis AD, or the relay lens 71 is eccentric in the direction parallel to the axis AD. It is possible to increase the light utilization efficiency by centering and decentering the relay lens 73 in a direction parallel to the axis AD.

  According to the projection display apparatus according to the present embodiment, the relay lens is arranged with respect to the optical axis of the illumination optical system 1 so that the amount of the light beam incident on the irradiated surface 2b from the light intensity uniformizing element 6 is increased. The light utilization efficiency can be increased by holding it eccentrically.

  Furthermore, since the relay lens can be realized with a simple structure in which the relay lens is decentered in parallel with the axis AD, it can be realized at low cost.

  This embodiment shows an example, and a further effect can be obtained if the projection display device has a large distortion in the actual illumination region.

  In this embodiment, the relay optical system is shown as a relay lens group, but the same effect can be obtained even if the relay optical system has a mirror. When the relay optical system has a mirror, the positional relationship between the relay lens to be decentered and the DMD element 2 changes depending on the arrangement of the mirror. However, even in this case, the relay lens arranged on the light intensity uniformizing element 6 side with respect to the stop position of the illumination optical system 1 passes through the point on the line segment from the center of the relay lens to the vertex of the incident surface. The light utilization efficiency is increased by decentering the intersection line of the surface perpendicular to the optical axis of the illumination optical system 1 and the surface perpendicular to the illuminated surface 2b including the optical axis of the illumination optical system 1 as the movement axis. It is possible. Similarly, the relay lens arranged on the illuminated surface 2b side with respect to the position of the stop of the illumination optical system 1 passes through a point on the line segment from the center of the relay lens to the vertex of the exit surface, and the illumination optical system 1 If the line of intersection between the surface perpendicular to the optical axis and the surface that includes the optical axis of the illumination optical system 1 and is perpendicular to the surface 2b to be illuminated is decentered as a movement axis, the light utilization efficiency can be increased. is there.

  DESCRIPTION OF SYMBOLS 1 Illumination optical system, 1a Illumination optical axis, 2 DMD element, 2b Illuminated surface, 2c Actual illumination area of the conventional projection display apparatus, 3 Projection optical system, 4 Light source lamp, 5 Rotation color filter, 6 Light intensity equalization Element, 6a entrance surface, 6b exit surface, 7 relay lens group, 8 base portion, 10a to 10e projection display device.

Claims (9)

An illumination optical system having a light source, a light intensity uniformizing element that uniformizes the intensity distribution of the light beam emitted from the light source, and a lens group that collects the light beam emitted from the light intensity uniformizing element;
A reflection type light valve having an image forming area irradiated with a light beam condensed by the lens group, and forming an image in the image forming area;
A projection optical system for enlarging and projecting an image formed in the image forming area,
In the lens group, a lens held in a state of being rotated about a line of intersection between a plane perpendicular to the optical axis of the illumination optical system and a plane parallel to the image forming area is a diaphragm of the illumination optical system. The vertex through which the rotation axis passes is set based on the relationship with the position, and the optical axis of the illumination optical system is increased so that the amount of the light beam incident on the image forming area from the light intensity uniformizing element is increased. A projection display device characterized by being tilted. The lens is a first lens disposed on the image forming region side of the stop position of the illumination optical system, and the rotation axis is a first rotation axis of the first lens,
The projection display device according to claim 1, wherein a vertex through which the first rotation axis of the first lens passes is an exit surface vertex of the first lens. The lens is a second lens disposed closer to the light intensity uniformizing element than the position of the diaphragm of the illumination optical system, and the rotation axis is a second rotation axis of the second lens,
The projection display device according to claim 1, wherein a vertex through which the second rotation axis of the second lens passes is an entrance surface vertex of the second lens. The lens group further includes a third lens different from the first lens,
The third lens is disposed on the light intensity uniformizing element side with respect to the stop position of the illumination optical system and rotates around a third rotation axis.
The projection display device according to claim 2, wherein an apex through which the third rotation axis of the third lens passes is an apex surface apex of the third lens. 5. The projection according to claim 1, wherein the lens is tilted and held so that an angle formed between a surface including the image forming region and an optical axis of the lens is small. Type display device. A light source;
A light intensity uniformizing element for uniformizing the intensity distribution of the light beam emitted from the light source;
A reflective light valve that has an image forming area and forms an image in the image forming area based on the luminous flux;
A lens for guiding the light beam emitted from the light intensity uniformizing element to the image forming area;
A projection optical system for enlarging and projecting the image formed in the image forming area,
The lens is arranged with respect to the optical axis of an illumination optical system including the light source, the light intensity uniformizing element, and the lens so that an amount of a light beam incident on the image forming area from the light intensity uniformizing element is increased. A projection display device characterized by being eccentrically held. The lens is decentered with a line of intersection between a plane perpendicular to the optical axis of the illumination optical system and a plane including the optical axis of the illumination optical system and perpendicular to the image forming area as a movement axis. Item 7. The projection display device according to Item 6. When the lens is disposed closer to the image forming area than the position of the stop of the illumination optical system,
The projection display device according to claim 7, wherein the lens is decentered in a direction in which a distance from the image forming region is reduced. When the lens is disposed closer to the light intensity equalizing element than the position of the stop of the illumination optical system,
The projection display device according to claim 7, wherein the lens is decentered in a direction in which a distance from the image forming region increases.

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