JP2007293274A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector in which reductions in its weight and size are easily achieved and a contrast increase is ensured with an inexpensive dimming mechanism. <P>SOLUTION: The diaphragm device 33 of an illuminating optical system 30 adjusts quantity of light by opening or closing a pair of intercepting plates 33a and 33b slid in the direction of X axis. Accordingly, the contrast of an image finally projected on a screen by a projection optical system 80 can be increased as necessity requires. In this case, the pair of intercepting plates 33a and 33b are slid in the direction of X axis such that they are laid lengthwise. This makes it possible to stably move a drive section, including the guide 33d of the diaphragm device 33, etc at relatively high accuracy. At this time, the drive section, including the guide 33d, etc., is restricted from projecting out in the direction Y. This makes it possible to vertically thin the illuminating optical system 30, which makes it easy to vertically thin the projector 10 as well. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a projector incorporating a light modulation device constituted by a liquid crystal panel or the like and an illumination device for illuminating the light modulation device.

  As a conventional projector, a pair of aperture plates that open and close in a double-split manner are provided between two-stage lens arrays provided in the illumination device, and the brightness difference between the white display and black display of the projector is adjusted by adjusting the open / close state of both aperture plates. There is known a technique for increasing the contrast of the projected image to increase the contrast (see Patent Document 1).

JP 2004-69966 A

  However, the diaphragm plate as described above rotates both the diaphragm plates around different axes, so that the drive device including the motor and the interlocking mechanism is likely to be complicated and heavy, which reduces the cost and weight of the projector. There were cases where it was an obstacle.

  Further, since the diaphragm plate driving device as described above is arranged above and below the optical path of the illumination light, it tends to increase the thickness of the illumination optical system, which may be an obstacle to miniaturization of the projector. .

  SUMMARY An advantage of some aspects of the invention is that it provides a projector capable of increasing contrast with a light control mechanism that is easy to reduce in weight and size and is inexpensive.

  In order to solve the above problems, a projector according to the present invention is uniform by (a) a light source device that emits light for illumination, and (b) a light beam emitted from the light source device that is divided into partial light beams and superimposed. And (c) a light modulation unit that modulates light from the illumination device according to image information, and (d) a projection optical system that projects light modulated by the light modulation unit. In this projector, the homogenizing optical system is a pair of shields that open and close by sliding back and forth in the direction of the X axis that is parallel to one side of the illumination area corresponding to the screen and perpendicular to the optical axis. A diaphragm device having a plate is included. Each shielding plate is formed of a plurality of edge portions having different inclinations and / or curvatures, and has a substantially symmetrical edge shape with the X axis interposed therebetween.

  In the projector described above, the aperture device of the uniformizing optical system has a pair of shielding plates that open and close by sliding back and forth in the X-axis direction. Therefore, the light modulation from the light source device is appropriately performed with the light modulated The contrast of the projected image can be increased as necessary. At that time, the pair of shielding plates are slid back and forth in the X-axis direction perpendicular to the optical axis, so that the drive unit of the diaphragm device can be operated stably with relatively high accuracy, and the X-axis of the illumination section. It is possible to reduce the thickness in the direction perpendicular to (the top and bottom of the projector, that is, the vertical direction of the screen). That is, since the drive unit of the pair of shielding plates is configured by the slide moving mechanism, the pair of shielding plates can be moved while being stably supported, and the driving mechanism is easily arranged in the lateral direction of the illumination section. As a result, the thickness in the vertical direction of an illumination optical system including a uniformizing optical system can be easily reduced.

  According to a specific aspect or aspect of the invention, in the projector, the first edge portion close to the X axis among the plurality of edge portions has a negative slope in the first quadrant, and one edge The second edge portion farther from the X axis than the portion has a positive slope in the first quadrant. In this case, the first edge portion close to the X-axis has an inclination so as to leave the optical axis side of the origin when narrowing down, and allows a good quality light beam in the central portion close to the optical axis to pass through without being shielded to the end. Can do. On the other hand, the second edge portion far from the X-axis is opposite in inclination to the first edge portion, and prevents the stroke of the pair of shielding plates from increasing during dimming.

  According to another aspect of the invention, at least one of the plurality of edge portions is a smooth curve. In this case, since the angle of the edge portion is smoothly changed, the increase ratio of the shielding with respect to the movement amount in the X-axis direction can be smoothly changed according to the distance from the X-axis.

  According to still another aspect of the present invention, there is provided a driving device that adjusts the amount of light shielded by a pair of shielding plates by moving the pair of shielding plates in directions opposite to each other with respect to the X-axis direction corresponding to the longitudinal direction of the illumination region. Further prepare. In this case, the diaphragm device can be opened and closed by moving the pair of shielding plates provided in the diaphragm device in the opposite directions at an appropriate timing by the driving device.

  According to still another aspect of the present invention, the pair of shielding plates have shapes symmetrical to each other across the Y axis passing through the optical axis and perpendicular to the X axis in a plane perpendicular to the optical axis. In this case, the pair of shielding plates are arranged symmetrically with respect to the X axis and the Y axis, can perform light shielding with a good balance around the optical axis, and can perform smooth light quantity adjustment with little deviation around the optical axis. become.

  According to still another aspect of the present invention, the light source device includes a light emitting tube having a light emitting portion that emits light, and a reflecting mirror that reflects and converges the light emitted from the light emitting tube, and is a uniformizing optical The system includes a two-stage lens array arranged in a matrix in the X-axis direction and the Y-axis direction. In this case, illumination light in which high-intensity light source light from the arc tube is made uniform can be obtained by the two-stage lens array.

  According to still another aspect of the present invention, the aperture device is disposed in the vicinity of the lens array at the rear stage of the two-stage lens array. In this case, the point light source images individually formed by the front lens array are formed before and after the rear lens array. However, the unevenness of brightness in the illuminated area is generated by shielding light in the vicinity of the front and rear of the point light source. It can be reduced relatively.

  According to still another aspect of the invention, the light modulation unit includes a plurality of light modulation devices for each color that individually modulate a plurality of color lights. In this projector, the color separation optical system that separates the light from the illumination device into each color light and supplies the light to the light modulation device for each color, and the light combining optical that combines the light of each color modulated by the liquid crystal light valve for each color And further comprising a system. In this case, a light modulation device can be provided for each color, and a high-contrast and high-quality image can be projected.

[First Embodiment]
FIG. 1 is a conceptual diagram illustrating the configuration of the optical system of the projector according to the first embodiment of the invention.

  The projector 10 is an optical device for modulating a light beam emitted from a light source according to image information to form an optical image, and enlarging and projecting the optical image on a screen. The light source lamp unit 20, illumination optics The system 30 includes a color separation device 40, a light modulation unit 60, a cross dichroic prism 70, and a projection optical system 80.

  The light source lamp unit 20 is a light source device that collects and emits light beams emitted from the light source lamp 21 to the surroundings and illuminates the light modulation unit 60 via the illumination optical system 30 and the like, and is a light source lamp that is a light emitting tube. 21, a concave mirror 22 that is a concave ellipse that reflects the light source light emitted from the light source lamp 21, and a concave lens 23 that collimates the light source light reflected by the concave mirror 22. In the light source lamp unit 20, the light source light emitted from the light source lamp 21 is collimated through the concave mirror 22 and the concave lens 23 and emitted to the front side, that is, the illumination optical system 30 side. Instead of the elliptical concave mirror 22 described above, various concave mirrors such as a paraboloid can be used. When a parabolic concave mirror is used, a parallel light beam can be emitted from the light source lamp unit 20 without providing the concave lens 23 or the like after the concave mirror 22.

  The illumination optical system 30 divides the luminous flux emitted from the light source lamp unit 20 into a plurality of partial luminous fluxes and superimposes them on a target illumination area to make the illuminance uniform, and illuminate the illumination light in a specific direction. The optical system converts light into polarized light, and includes a first lens array 31, a second lens array 32, a diaphragm device 33, a polarization conversion device 34, and a superimposing lens 35. Among these, the lens arrays 31 and 32, the diaphragm device 33, and the superimposing lens 35 are a uniformizing optical system for uniformizing illumination light.

  The first lens array 31 has a function as a light beam splitting optical element that splits a light beam emitted from the light source lamp 21 into a plurality of partial light beams, and is arranged in a matrix in a plane orthogonal to the system optical axis OA. A plurality of small lenses are provided. The contour shape of each small lens is set so as to be almost similar to the shape of the image forming area of the liquid crystal panels 61b, 61g, 61r constituting the light modulation unit 60 described later. The second lens array 32 is an optical element that collects a plurality of partial light beams divided by the first lens array 31 described above, and in the same manner as the first lens array 31, a matrix is formed in a plane orthogonal to the system optical axis OA. However, since it is intended to collect light, the contour shape of each small lens accurately corresponds to the shape of the image forming area of the liquid crystal panels 61b, 61g, 61r. There is no need.

  The diaphragm device 33 includes a pair of shielding plates 33a and 33b, a guide 33d for guiding the movement of both shielding plates 33a and 33b, and a drive device 33f for opening and closing both shielding plates 33a and 33b. Each of the shielding plates 33a and 33b is a thin plate member, and has a special shape to be described later. The guide 33d guides the shielding plates 33a and 33b to enable smooth reciprocation in the AB direction parallel to the paper surface and perpendicular to the system optical axis OA. The drive device 33f is composed of a motor and other devices, and drives both shielding plates 33a and 33b at a necessary timing to adjust their open / closed state. That is, the drive device 33f can move one shielding plate 33a to an arbitrary position along the guide 33d, and the other shielding plate 33b also corresponds to a position along the guide 33d via an interlocking unit (not shown). Can be moved to. At this time, as will be described in detail later, the shielding plate 33a and the shielding plate 33b have symmetrical shapes with respect to the AB direction with respect to the system optical axis OA, and sandwich the system optical axis OA with respect to the AB direction. Therefore, the aperture AP formed between the shielding plate 33a and the shielding plate 33b has a symmetrical shape with respect to the AB direction across the system optical axis OA. Here, the X-axis corresponds to the longitudinal direction that is the horizontal side of the rectangular illumination area, and the Y-axis corresponds to the lateral direction that is the vertical side of the illumination area.

  FIG. 2 is a front view for explaining a main part of the diaphragm device 33. The shielding plates 33a and 33b have edge shapes that are vertically symmetrical with respect to the X axis that is orthogonal to the system optical axis OA and extends in the lateral direction. Further, the right shielding plate 33a and the left shielding plate 33b have the same edge shape, and are arranged symmetrically with respect to each other with the Y axis extending perpendicularly to the system optical axis OA.

  First, the shape of the shielding plate 33a on the right side of the drawing will be described. The edge EG on the opening AP side of the shielding plate 33a is formed in a position close to the X axis in the first quadrant at the upper right in the drawing and has a first edge portion E1 having a negative inclination and a position far from the X axis. And a linear second edge portion E2 which is formed and has a positive inclination. The same applies to the fourth quadrant at the lower right in the figure, but the inclination direction is reversed due to symmetry, and the edge EG of the shielding plate 33a is negative with the arc-shaped first edge portion E1 having a positive inclination. And a linear second edge portion E2 having an inclination of. When observed as a whole, the shielding plate 33a has an arc-shaped first edge portion E1 that is recessed toward the root side at the center, and a linear second edge portion E2 that is widened toward the root side at the periphery. Have. As a result, at the pair of boundaries between the first edge portion E1 and the second edge portion E2, protrusions sharpened toward the tip are formed.

  The above is a description of the shielding plate 33a on the right side of the drawing, but the shape of the shielding plate 33b on the left side of the drawing is the same as that of the shielding plate 33a. However, the left shielding plate 33b and the right shielding plate 33a are arranged symmetrically with respect to the Y axis. That is, both shielding plates 33a and 33b have edge portions E1 and E2 having the same shape, but are arranged in a state where they are folded back so as to be symmetrical with respect to the Y axis. It should be noted that both the shielding plates 33a and 33b are driven by the driving device 33f shown in FIG. 1 so that the both shielding plates 33a and 33b are separated from the system optical axis OA by an equal distance. As a result, for example, the state can be changed from a relatively close state as shown by a solid line to a separated state as shown by an alternate long and short dash line, and vice versa. At this time, both the shielding plates 33a and 33b are guided by the guide 33d and slide smoothly, so that the light can be adjusted precisely and smoothly. Specifically, by operating both the shielding plates 33a and 33b as described above, the illuminance fluctuation range of the illumination light emitted from the illumination optical system 30 can be set to 0 to 100%, for example. The illuminance can be changed substantially linearly with the opening and closing of the shielding plates 33a and 33b.

  2 indicate the small lenses 32a constituting the second lens array 32 behind. By opening and closing both shielding plates 33a and 33b as shown in the figure, the shape of the aperture AP formed between them is increased / decreased / changed, and the amount of light supplied to the second lens array 32 is changed. At this time, since both the shielding plates 33a and 33b are arranged immediately before the second lens array 32, uneven illumination is provided in the illumination area of the light modulation unit 60 described later, that is, in the image formation areas of the liquid crystal panels 61b, 61g, and 61r of the respective colors. Is unlikely to occur. In this example, the shielding plates 33a and 33b are disposed immediately before the second lens array 32. However, the diaphragm device 33 including the shielding plates 33a and 33b can be disposed immediately after the second lens array 32. The same effect can be obtained.

  In the diaphragm device 33 described above, the pair of shielding plates 33a and 33b are slid in the front and rear in the X-axis direction perpendicular to the system optical axis OA, that is, in the AB direction, so that the guide 33d and the drive device 33f are stabilized with relatively high accuracy. In addition, the thickness of the illumination optical system 30 in the Y-axis direction, and thus the thickness above and below the projector 10, can be reduced. In other words, the guide 33d and the drive device 33f are arranged so as to protrude in the lateral direction of the illumination optical system 30 (laterally on the ± X side of the lens array 32) in view of sliding both the shielding plates 33a and 33b in the lateral direction. However, this uses the dead space of the optical system. As a result, the guide 33d and the drive device 33f are arranged so that they hardly protrude in the longitudinal direction of the illumination optical system 30 (lateral direction on the ± Y side of the lens array 32), so that at least the thickness of the illumination optical system 30 is obtained. Can be suppressed.

  On the other hand, when the pair of shielding plates 33a and 33b is slid in the X-axis direction, the illuminance adjustment resolution or adjustment accuracy is higher than when the pair of shielding plates 33a and 33b are slid in the Y-axis direction. There is a tendency to decrease. This is because the horizontal number of each small lens 32a constituting the second lens array 32 is smaller than the vertical number. That is, each small lens 32a has a similar shape to the illumination area of the light modulation unit 60, that is, the image forming areas of the liquid crystal panels 61b, 61g, 61r of each color, but this aspect ratio is 3: 4 or 9:16. In general, the number of small lenses 32a in the horizontal direction is inversely proportional to the number of the small lenses 32a. As a result, the matrix element of the light source (light source image) formed at the center of each small lens 32a and the periphery thereof has less horizontal direction compared to the vertical direction, and both shielding plates 33a and 33b are connected to X. The ratio of change in illuminance when opening and closing in the direction tends to be larger than the ratio of change in illuminance when both shielding plates 33a and 33b are opened and closed in the Y direction. Therefore, the shape and movement method of the shielding plates 33a and 33b for adjusting the light amount are extremely important for adjusting the illumination light amount on the image forming area of the light modulation unit 60 described later.

  In both shielding plates 33a and 33b, the first edge portion E1 close to the X axis has an inclination so as to leave the vicinity of the system optical axis OA, and the good-quality light beam in the central portion close to the system optical axis OA is the last. Can be transmitted without blocking. In both the shielding plates 33a and 33b, the second edge portion E2 far from the X axis is opposite in inclination to the first edge portion E1, and the dimming of opening and closing both the shielding plates 33a and 33b is performed by the two shielding plates 33a and 33b. It is possible to prevent the stroke in the Y-axis direction from increasing. Further, both edge portions E1 and E2 have an inclination of a certain level or more with respect to the Y axis, and have almost no portion that is 90 ° with respect to the X axis. Therefore, both shielding plates 33a and 33b Are moved so as to be close to each other in the X-axis direction, a large number of point-like light sources are blocked together, and the amount of illumination light is prevented from decreasing in a staircase pattern. On the other hand, the inclination of both edge portions E1 and E2 with respect to the X-axis is about 45 ° or more as a whole, and the point light source when both shielding plates 33a and 33b move so as to be close to each other in the X-axis direction. The increase rate of the shielding amount can be made relatively large. Therefore, the amount of illumination light passing through the diaphragm device 33 can be changed relatively steeply as a whole.

  The polarization conversion device 34 is formed of a PBS array, and has the role of aligning the polarization direction of the partial light beams divided by the first lens array 31 and emitted from the second lens array 32 through the diaphragm device 33 to one-way linearly polarized light. Have Although not shown in detail, the polarization conversion device 34 has a configuration in which polarization separation films and reflection mirrors that are inclined with respect to the system optical axis OA are alternately arranged. The former polarization separation film transmits one polarized light beam among the P-polarized light beam and S-polarized light beam included in each partial light beam, and reflects the other polarized light beam. The other polarized light beam reflected is bent in the optical path by the latter reflecting mirror, and is emitted in the emission direction of the one polarized light beam, that is, the direction along the system optical axis OA. Either one of the polarized light beams emitted from the polarization separation film or the reflection mirror is polarized and converted by a phase difference plate provided in a stripe shape on the light emission surface of the polarization conversion device 34, and the polarization directions of all the polarized light beams are aligned. . By using such a polarization conversion device 34, it is possible to align the light beam emitted from the light source lamp 21 with a polarized light beam in one direction, so that the utilization factor of the light source light used in the light modulation unit 60 is improved. Can do.

  The superimposing lens 35 condenses a plurality of partial light beams that have passed through the first lens array 31, the second lens array 32, and the polarization conversion device 34, and superimposes them on the image forming regions of the liquid crystal panels 61b, 61g, 61r. It is an optical element for making it enter. The light beam emitted from the superimposing lens 35 is emitted to the color separation device 40 at the next stage while being made uniform. In other words, the illumination light that has passed through both the lens arrays 31 and 32 and the superimposing lens 35 passes through the color separation device 40 described in detail below, and the illumination region of the light modulation unit 60, that is, the images of the liquid crystal panels 61b, 61g, and 61r for each color Uniformly illuminate the formation area.

  The color separation device 40 includes first and second dichroic mirrors 41a and 41b, reflection mirrors 42a, 42b, and 42c, field lenses 43b, 43g, and 43r, and relay lenses 45 and 46. Among these, the color separation optical system including the first and second dichroic mirrors 41a and 41b has three illumination lights, blue (B) color light, green (G) color light, and red (R) light. Separated into two luminous fluxes. Each dichroic mirror 41a, 41b is an optical element obtained by forming on a transparent substrate a dielectric multilayer film having a wavelength selection function of reflecting a light beam in a predetermined wavelength region and transmitting a light beam in another wavelength region. Yes, they are arranged in an inclined state with respect to the system optical axis OA. The first dichroic mirror 41a reflects the blue light LB among the three colors of blue, green, and red (B, G, and R), and transmits the green light LG and the red light LR. The second dichroic mirror 41b reflects the green light LG out of the incident green light LG and red light LR and transmits the red light LR. The field lenses 43b, 43g, and 43r for each color provided on the emission side of the color separation device 40 have each partial light beam emitted from the second lens array 32 and incident on the light modulation unit 60 with respect to the system optical axis OA. It is provided so as to have an appropriate degree of convergence or divergence. The pair of relay lenses 45 and 46 are disposed on the third optical path OP3 for red which is relatively longer than the first optical path OP1 for blue and the second optical path OP2 for green. The relay lenses 45 and 46 transmit the image formed immediately before the incident-side first relay lens 45 to the field lens 43r on the emission side as it is, so that light use efficiency due to light diffusion or the like is achieved. Is prevented. In the present embodiment, the relatively long third optical path OP3 is used for red, but the configuration of the dielectric multilayer film of the dichroic mirror of the color separation optical system is changed so that the third optical path OP3 is used for blue or green. It is also possible to do.

  In the color separation device 40, the illumination light incident from the light source lamp unit 20 via the illumination optical system 30 first enters the first dichroic mirror 41a. The blue light LB reflected by the first dichroic mirror 41a is guided to the first optical path OP1, and enters the final stage field lens 43b via the reflection mirror 42a. Further, the green light LG transmitted through the first dichroic mirror 41a and reflected by the second dichroic mirror 41b is guided to the second optical path OP2 and enters the field lens 43g at the final stage. Further, the red light LR that has passed through the second dichroic mirror 41b is guided to the third optical path OP3, and enters the final stage field lens 43r via the reflection mirrors 42b and 42c and the relay lenses 45 and 46.

  The light modulation unit 60 is disposed so as to sandwich the three liquid crystal panels (liquid crystal display panels) 61b, 61g, and 61r on which the three colors of illumination lights LB, LG, and LR are incident, and the liquid crystal panels 61b, 61g, and 61r. And three sets of polarizing filters 62b, 62g, and 62r. Here, for example, the liquid crystal panel 61b for blue light LB and the pair of polarizing filters 62b and 62b sandwiching the liquid crystal panel 61b constitute a liquid crystal light valve for two-dimensionally modulating the luminance of illumination light based on image information. . Similarly, the green light LG liquid crystal panel 61g and the corresponding polarizing filters 62g and 62g also constitute a green liquid crystal light valve, and the red light LR liquid crystal panel 61r and the polarizing filters 62r and 62r are also red. A liquid crystal light valve for use. Each of the liquid crystal panels 61b, 61g, 61r is a liquid crystal which is an electro-optical material sealed between a pair of transparent glass substrates. For example, each of the liquid crystal panels 61b, 61g, 61r is a polysilicon TFT as a switching element, The polarization direction of the polarized light beam incident on the light is modulated.

  In the light modulation unit 60, the blue light LB guided to the first optical path OP1 enters the illumination area provided at the position of the liquid crystal panel 61b via the field lens 43b and illuminates the image forming area in the liquid crystal panel 61b. . The green light LG guided to the second optical path OP2 enters the illumination area provided at the position of the liquid crystal panel 61g via the field lens 43g and illuminates the image forming area in the liquid crystal panel 61g. The red light LR guided to the third optical path OP3 enters the illumination area provided at the position of the liquid crystal panel 61r via the first and second relay lenses 45 and 46 and the field lens 43r, and forms an image in the liquid crystal panel 61r. Illuminate the area. Each of the liquid crystal panels 61b, 61g, 61r is a non-light-emitting and transmissive light modulation device for changing the spatial distribution of the polarization direction of incident illumination light. The color lights LB, LG, and LR incident on the liquid crystal panels 61b, 61g, and 61r are polarized in units of pixels in accordance with drive signals or control signals input as electrical signals to the liquid crystal panels 61b, 61g, and 61r. The state is adjusted. At that time, the polarization filters 62b, 62g, and 62r adjust the polarization direction of the illumination light incident on the liquid crystal panels 61b, 61g, and 61r, and a predetermined amount of light emitted from the liquid crystal panels 61b, 61g, and 61r. The modulated light in the polarization direction is extracted.

  Even if there is some unevenness in the distribution of the illumination light formed by the illumination optical system 30, and even if unevenness is formed in the illuminance of the image forming areas of the respective liquid crystal panels 61b, 61g, 61r, each liquid crystal panel. By applying correction for adjusting the transmittance distribution of 61b, 61g, 61r, it is possible to compensate for uneven brightness of the modulated light emitted from the light modulation unit 60 as a result.

  The cross dichroic prism 70 is a light combining optical system that forms a color image by combining optical images modulated for the respective color lights emitted from the polarization filters 62b, 62g, and 621r. The cross dichroic prism 70 has a substantially square shape in plan view in which four right angle prisms are bonded together, and a pair of dielectric multilayer films 71 and 72 intersecting in an X shape are formed at the interface where the right angle prisms are bonded to each other. Is formed. One first dielectric multilayer film 71 reflects blue light, and the other second dielectric multilayer film 72 reflects red light. The cross dichroic prism 70 reflects the blue light LB from the liquid crystal panel 61b by the first dielectric multilayer film 71 and emits the green light LG from the liquid crystal panel 61g to the first and second dielectrics. The light advances straight through the multilayer films 71 and 72, and the red light LR from the liquid crystal panel 61r is reflected by the second dielectric multilayer film 72 and emitted to the left in the traveling direction.

  The image light combined by the cross dichroic prism 70 in this way is projected as a color image on a screen (not shown) at an appropriate magnification through a projection optical system 80 as a magnification projection lens.

  As is apparent from the above description, according to the projector 10 of the present embodiment, the diaphragm device 33 provided in the illumination optical system 30 is configured to open and close the pair of shielding plates 33a and 33b that slide in the X-axis direction. Since the adjustment is performed, the contrast of the projection image finally projected on the screen by the projection optical system 80 can be increased as necessary. At that time, since the pair of shielding plates 33a and 33b are horizontally placed and slid in the X-axis direction, the drive unit including the guide 33d and the drive device 33f of the diaphragm device 33 can be operated stably with relatively high accuracy. Can be made. In this case, the driving unit including the guide 33d, the driving device 33f, and the like is disposed so as to protrude laterally, that is, in the X direction with respect to the first and second lens arrays 31, 32, but does not protrude so much in the Y direction. Therefore, the illumination optical system 30 is thinned vertically, and accordingly, the projector 10 is easily thinned vertically.

[Second Embodiment]
Hereinafter, a projector according to a second embodiment of the invention will be described. Note that the projector according to the second embodiment is obtained by partially changing the projector according to the first embodiment, and parts that are not particularly described are the same as those of the first embodiment.

  FIG. 3 is a diagram for explaining the shapes of the pair of shielding plates 133a and 133b constituting the diaphragm device 33 incorporated in the projector 10 according to the second embodiment. In this case, the right shielding plate 133a indicated by the solid line has not only the first and second edge portions E1 and E2 but also the third edge portion E3. Similarly, the left shielding plate 133b indicated by the dotted line has a third edge portion E3 together with the first and second edge portions E1 and E2. The third edge portion E3 is formed at a position closer to the X axis than the second edge portion E2, and is a constant light transmission portion hollowed out into a rectangle. That is, a rectangular opening AP corresponding to the third edge portion E3 remains even at the position where the diaphragm device 33 is most narrowed. Therefore, in the shape of the shielding plates 33a and 33b of the first embodiment, the illuminance variation range is set to 0 to 100%, whereas in the shape of the shielding plates 33a and 33b of the present embodiment, the illuminance variation range is set. For example, it can be set to about 16 to 100%. By doing so, it is not necessary to darken the illuminance by the illumination optical system 30 unnecessarily, and it becomes difficult for illuminance to change suddenly or vary around illuminance of about 20%. High accuracy can be achieved. In the present embodiment, the range of illuminance can be set to, for example, about 16 to 100%, and the diaphragm device 33 can be set at the most narrowed position so that a sudden change or variation in illuminance is unlikely to occur when the illuminance is about 20%. Although the rectangular aperture AP corresponding to the third edge portion E3 remains, the edge shape of the diaphragm device 33 is set so that the illuminance fluctuation range and the illuminance that is unlikely to cause a sudden change or variation in illuminance are set to a desired value. It can be set appropriately.

[Specific Examples]
As a specific example, shielding plates 33a and 133a as shown in FIGS. 2 and 3 were produced, and the amount of movement of the shielding plates 33a and 133a and the change in illuminance when a white image was projected onto the screen were examined.

  For comparison, shielding plates 533a, 533b, 533c, 533d, and 533e as shown in FIGS. The first shielding plate 533a has a flat edge, and the second and third shielding plates 533b and 533c have simple V-shaped edges, and the fourth and fifth shielding plates 533d and 533e. Has an arc edge.

  5 shows the shielding plates 33a and 133a as shown in FIGS. 2 and 3 and the shielding plates 533a, 533b, 533c, 533d and 533e as shown in FIGS. 4A to 4E. It is a graph which shows the relationship between the opening-and-closing movement amount of, and the illumination intensity on a screen. As is apparent from the figure, a stair-like change in illuminance appears strongly in the shielding plate 533a of the comparative example shown in FIG. Further, even in the shielding plate 533 d of the comparative example shown in FIG. Furthermore, in the case of the shielding plates 533b, 533c, and 533e of the comparative example as shown in FIGS. 4B, 4C, and 4E, the light control amount changes gradually and the strokes of the shielding plates 533b, 533c, and 533e are increased. Must be bigger. On the other hand, in the case of the shielding plate 33a of the embodiment shown in FIG. 2, a step-like change in illuminance does not occur, the change in the light control amount is large, and the stroke can be reduced. Similarly, the shielding plate 133a of the embodiment shown in FIG. 3 hardly causes a step-like change in illuminance and can make the stroke extremely small.

  Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and can be implemented in various modes without departing from the gist thereof. Such modifications are also possible.

  That is, in the above-described embodiment, the diaphragm device 33 is disposed in the vicinity of the front and rear of the second lens array 32. However, the diaphragm device 33 is disposed at the subsequent stage of the superimposing lens 35, or disposed before and after the first lens array 31. It is also possible.

  Further, the shape of the pair of shielding plates 33a and 33b is not limited to that shown in FIGS. 2 and 3 and the like. And can be changed appropriately according to the arrangement.

  In the projector 10 of the above embodiment, the illumination optical system 30 includes the lens arrays 31 and 32, the diaphragm device 33, the polarization conversion device 34, and the superimposing lens 35. However, the lens arrays 31 and 32, the polarization conversion device 34, and the like. Can be omitted.

  In the above-described embodiment, the color separation of the illumination light is performed using the color separation device 40, and each color is modulated by the light modulation unit 60, and then the image of each color is synthesized by the cross dichroic prism 70. However, an image can also be formed by a single liquid crystal panel, that is, a liquid crystal light valve.

  In this embodiment, an example in which the present invention is applied to a transmissive projector has been described. However, the present invention can also be applied to a reflective projector. Here, “transmission type” means that the light valve including the liquid crystal panel is a type that transmits light, and “reflection type” is a type that the light valve reflects light. Means.

  In addition, the present invention can be applied to a front projection type projector that projects from the side that observes the projected image, and a rear projection type projector that projects from the side opposite to the side that observes the projected image.

FIG. 2 is a plan view for explaining an optical system of the projector according to the first embodiment. FIG. 2 is a front view illustrating a diaphragm device incorporated in the projector of FIG. 1. The schematic diagram which shows the projector which concerns on 2nd Embodiment. (A)-(e) is a figure explaining the shape of the aperture_diaphragm | restriction of a comparative example. The graph explaining the light control amount of an Example and a comparative example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Projector, 20 ... Light source lamp unit, 21 ... Light source lamp, 22 ... Concave mirror, 30 ... Illumination optical system, 31 ... 1st lens array, 32 ... 2nd lens array, 32a ... Small lens, 33 ... Aperture device, 33a 33b ... shielding plate, 33d ... guide, 33f ... drive device, 34 ... polarization conversion device, 35 ... superimposing lens, 40 ... color separation device, 41a, 41b ... dichroic mirror, 43b, 43g, 43r ... field lens, 60 ... Light modulator 61b, 61g, 61r ... liquid crystal panel, 62b, 62g, 62r ... polarizing filter, 70 ... cross dichroic prism, 80 ... projection optical system, AP ... aperture, E1 ... first edge portion, E2 ... second edge Part, EG: Edge, LB, LG, LR: Each color light, OA: System optical axis.

Claims (8)

A light source device for emitting light for illumination;
A homogenizing optical system for homogenizing the light emitted from the light source device by dividing the light into a plurality of partial light beams and superimposing them;
A light modulator that modulates light from the illumination device according to image information;
A projection optical system for projecting the light modulated by the light modulation unit,
The homogenizing optical system includes a pair of shielding plates that open and close by sliding back and forth in the direction of the X axis that is parallel to one side of the illumination area corresponding to the screen and intersects perpendicularly to the optical axis. Including
Each of the shielding plates is a projector having a substantially symmetrical edge shape formed by a plurality of edge portions different from each other in at least one of inclination and curvature and sandwiching the X axis.   A first edge portion close to the X axis among the plurality of edge portions has a negative slope in the first quadrant, and a second edge portion farther from the X axis than the one edge portion is positive in the first quadrant. The projector according to claim 1, having an inclination of   The projector according to claim 1, wherein at least one of the plurality of edge portions is a smooth curve.   The said diaphragm | throttle device contains the drive device which adjusts the light-shielding amount by a pair of said shielding board by moving a pair of said shielding board to a mutually opposing direction regarding the X-axis direction corresponding to the longitudinal direction of the said illumination area. The projector according to any one of claims 1 to 3.   5. The pair of shielding plates according to claim 1, wherein the pair of shielding plates have shapes symmetrical to each other with a Y axis passing through the optical axis and perpendicular to the X axis in a plane perpendicular to the optical axis. The projector described.   The light source device includes a light-emitting tube having a light-emitting portion that emits light, and a reflecting mirror that reflects and converges the light emitted from the light-emitting tube, and the uniformizing optical system includes an X-axis direction and a Y-axis. The projector according to any one of claims 1 to 5, comprising a two-stage lens array arranged in a matrix in the direction.   The projector according to claim 6, wherein the aperture device is disposed in the vicinity of the lens array at the rear stage of the two-stage lens array. The light modulation unit includes a plurality of light modulation devices for each color that individually modulate a plurality of color lights,
A color separation optical system that separates light from the illumination device into light of each color and supplies the light to a light modulation device for each color; and a light combining optical system that combines light of each color modulated by the liquid crystal light valve for each color The projector according to any one of claims 1 to 7, further comprising:

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