JP5239279B2 - projector - Google Patents

Description

  The present invention relates to a projector, and more particularly to a technology of a projector capable of proximity projection that projects light from a position close to an irradiated surface.

  Many front projection projectors that have been widely used in the past are installed at a position away from the screen to some extent in order to secure a projection distance. When the projector is installed at a position away from the screen, it is necessary to secure a place where there is no obstacle that blocks light in the optical path from the projector to the screen. Such restrictions on the installation position of the projector become more prominent as the display screen becomes larger. In particular, it is difficult to display a large screen in a small room. In addition, consideration must be given to prevent people from entering the optical path while displaying an image.

  In recent years, a technique for performing close-up projection using a front projection type projector has been proposed. By enabling the close-up projection, for example, the projector can be arranged at a position close to the wall surface. By making it possible to place the projector at a position close to the wall surface, for example, within a few tens of centimeters of the wall surface, restrictions on the installation position of the projector can be reduced, and space can be saved. In addition, it is possible to display a large screen even in a small room, and it is possible to reduce consideration for people entering the optical path. A projector that performs close-up projection employs an ultra-short focus optical system. An ultra-short focal length optical system can display a large screen at a short projection distance. In order to realize an ultra-short focus, an optical element that greatly widens the angle of light is required. In order to widen the angle by using only an optical element that transmits light, for example, a lens, a large cost is required. On the other hand, for example, in the technique proposed in Patent Document 1, an ultrashort focus is realized by a combination of only aspherical mirrors.

JP 2002-40326 A

  Many front projection projectors that have been widely used in the past have a zoom function for adjusting the screen size. In general, the zoom function of a projector is realized by adjusting the position of an optical element constituting an optical system. In the case of an ultrashort focal length optical system such as the configuration proposed in Patent Document 1, a very high degree of difficulty is required only for a design that enables a large wide angle. For this reason, it is very difficult to design such that a zoom function is incorporated in a configuration that enables a wide angle of view. Even if a design incorporating a zoom function is possible, the configuration becomes complicated and the cost increases significantly. Under such circumstances, many projectors equipped with an ultra-short focus optical system such as the configuration proposed in Patent Document 1 ensure the zoom function by a method of moving the projector body. It is inconvenient to move the projector body every time the screen size is adjusted, and the permanent installation of the projector is limited. As described above, the conventional technology has a problem that it is difficult to realize a configuration that enables close projection and can easily adjust the screen size. The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a projector capable of easily adjusting the screen size when performing proximity projection.

  In order to solve the above-described problems and achieve the object, according to the present invention, a light source unit and an image forming unit that displays an image of a desired size on an irradiated surface using light from the light source unit. And a projection engine unit that projects light according to an image signal onto the irradiated surface, and a housing that houses the projection engine unit, the projection engine unit being along the optical path in the housing A projector that is movable in a direction can be provided.

  The screen size can be adjusted by moving the projection engine unit and changing the projection distance. By moving the projection engine unit within the housing, it is possible to eliminate the need to move the projector once installed. Therefore, it is possible to realize the permanent fixing of the projector and the zoom function. In particular, in the case of using an ultrashort focal length optical system, the screen size can be significantly changed even when the projection engine unit is moved so as to fit in a normal housing. By eliminating the need for a design that incorporates a zoom function for the optical system of the projection engine unit, it is possible to easily realize the zoom function without encouraging the difficulty in designing the optical system and complicating the configuration. Since the projection engine unit only needs to be movable, the configuration can be easily designed, and the manufacturing cost can be reduced. In addition, a highly reliable and highly accurate zoom mechanism can be realized with a simple configuration. Thus, a projector capable of easily adjusting the screen size can be obtained when performing close-up projection.

  As a preferred aspect of the present invention, it is desirable that the image forming unit has a wide angle reflection unit that widens light by reflection. As a result, it is possible to achieve a wide angle of light and a configuration capable of proximity projection.

  As a preferred aspect of the present invention, it is desirable that the image forming unit has a projection lens, and the wide-angle reflection unit widens the light from the projection lens. The projection lens performs image formation and a wide angle of light on the irradiated surface. The wide-angle reflection part broadens the angle of light from the projection lens. As a result, it is possible to achieve a configuration capable of close projection.

  As a preferred aspect of the present invention, it is desirable that the projection lens and the wide-angle reflecting portion are arranged so that the optical axes are substantially coincident with each other, and the light is shifted to a specific side with respect to the optical axis. By shifting the light from the optical axis to a specific side, it is possible to align the traveling direction of the light so as to form a large incident angle with respect to the irradiated surface. Thereby, proximity projection can be performed.

  Further, as a preferred aspect of the present invention, it is desirable that the projection engine unit is configured so that focus adjustment is possible. When adjusting the screen size, it is necessary to adjust the focus due to a change in the projection distance. As a result, a high-quality image can be displayed each time the screen size is adjusted.

  In a preferred aspect of the present invention, the projection engine unit includes a projection lens including a plurality of optical elements, and a wide angle reflection unit that widens light from the projection lens, and constitutes the projection lens. It is desirable that at least one of the elements is movable in the optical axis direction. Thereby, it can be set as the structure in which focus adjustment is possible.

  Moreover, as a preferable aspect of the present invention, it is desirable that at least one optical element arranged on the wide angle reflection portion side of the optical elements is movable. Thereby, focus adjustment can be performed with a simple configuration that can be easily designed.

  As a preferred aspect of the present invention, it is desirable that the image forming unit has a plurality of mirrors, and at least one of the mirrors is movable. Thereby, it can be set as the structure in which focus adjustment is possible.

  In a preferred aspect of the present invention, the image forming unit preferably includes a spatial light modulation device that modulates light from the light source unit according to an image signal. When the light from the light source unit is modulated by the spatial light modulator, the light source unit may emit a predetermined light amount, and there is no need to adjust the light amount according to the image signal. Thereby, an image can be easily displayed on the irradiated surface.

  As a preferred embodiment of the present invention, the light source unit preferably emits laser light, and the image forming unit preferably has a scanning unit that displays an image on the irradiated surface by scanning the laser light from the light source unit. . When displaying an image on the irradiated surface by scanning the laser beam from the light source with a scanning unit, it is necessary to adjust the light source according to the image signal, but the image can be displayed without using a projection lens. It becomes. Thereby, an image can be easily displayed on the irradiated surface.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration of a projector 10 according to Embodiment 1 of the present invention. The projector 10 is a front projection type projector that projects light according to an image signal. The projector 10 performs close-up projection from a position close to the irradiated surface, for example, a position about several tens of centimeters from the wall surface W on which the screen 16 is arranged. The projector 10 has a projection engine unit 11. The projection engine unit 11 projects the light modulated according to the image signal onto the screen 16 that is the irradiated surface. The projection engine unit 11 includes an optical engine 12, a projection lens 13, and an aspherical mirror 14. The optical engine 12, the projection lens 13, and the aspherical mirror 14 are housed in the projection engine unit 11, and are configured to be integrally movable by moving the projection engine unit 11.

  FIG. 2 shows a schematic configuration of the optical engine 12. The red (R) light LED 21 </ b> R, which is a solid light source, is a light source unit that supplies R light. The R light from the red (R) LED 21R is collimated by the collimator lens 22 and then enters the R light spatial light modulator 23R. The spatial light modulator 23R for R light is a spatial light modulator that modulates R light according to an image signal, and is a transmissive liquid crystal display device. The R light modulated by the R light spatial light modulator 23R is incident on a cross dichroic prism 24 which is a color synthesis optical system.

  The green (G) light LED 21G, which is a solid light source, is a light source unit that supplies G light. The G light from the green (G) LED 21G is collimated by the collimator lens 22 and then enters the G light spatial light modulator 23G. The G light spatial light modulation device 23G is a spatial light modulation device that modulates G light according to an image signal, and is a transmissive liquid crystal display device. The G light modulated by the G light spatial light modulator 23G enters the cross dichroic prism 24 from a different side from the R light.

  The blue (B) light LED 21 </ b> B that is a solid light source is a light source unit that supplies B light. The B light from the blue (B) light LED 21B is collimated by the collimator lens 22 and then enters the B light spatial light modulator 23B. The B light spatial light modulation device 23B is a spatial light modulation device that modulates B light according to an image signal, and is a transmissive liquid crystal display device. The B light modulated by the B light spatial light modulator 23B enters the cross dichroic prism 24 from a side different from the R light and the G light. The optical engine 12 may be configured to use a uniformizing optical system that uniformizes the intensity distribution of the light beam, for example, a rod integrator, a fly-eye lens, or a superimposing lens.

  The cross dichroic prism 24 includes two first dichroic films 25 and second dichroic films 26 arranged so as to be substantially orthogonal to each other. The first dichroic film 25 reflects R light and transmits G light and B light. The second dichroic film 26 reflects B light and transmits R light and G light. The cross dichroic prism 24 combines the R light, G light, and B light incident from different sides and emits the light toward the projection lens 13. The projection lens 13 projects the light synthesized by the cross dichroic prism 24.

  As the transmissive liquid crystal display device, for example, a high temperature polysilicon TFT liquid crystal panel (HTPS) can be used. The optical engine 12 is not limited to the case where a transmissive liquid crystal display device is used as the spatial light modulator. As the spatial light modulator, a reflective liquid crystal display (Liquid Crystal On Silicon; LCOS), DMD (Digital Micromirror Device), GLV (Grating Light Valve), or the like may be used. The projector 10 is not limited to a configuration including a spatial light modulator for each color light. The projector 10 may be configured to modulate two or three color lights with one spatial light modulator. The optical engine 12 is not limited to the case where an LED is used as the light source unit. As a light source part, you may use lamps, such as solid light sources other than LED, such as a laser light source, and an ultrahigh pressure mercury lamp.

  Returning to FIG. 1, the aspherical mirror 14 is provided at a position facing the projection lens 13. The aspherical mirror 14 is a wide-angle reflecting part that widens the light from the projection lens 13 by reflection, and has an aspherical curved surface. The aspherical mirror 14 has a function of widening the light from the projection lens 13 and a function of bending the light from the projection lens 13 and traveling in the direction of the screen 16. The spatial light modulator 23R for R light, the spatial light modulator 23G for G light, the spatial light modulator 23B for B light, the projection lens 13 and the aspherical mirror 14 are red (R) light LED 21R as a light source unit, green (G) An image forming unit that projects and displays an image of a desired size on the screen 16 that is an irradiated surface using light from the light LED 21G and the blue (B) light LED 21B. The aspherical mirror 14 can be configured, for example, by forming a reflective film on a substrate having a resin member or the like. As the reflective film, a highly reflective member layer, for example, a metal member layer such as aluminum, a dielectric multilayer film, or the like can be used. Further, a protective film having a transparent member may be formed on the reflective film.

  By making the aspherical mirror 14 into a curved surface shape, it becomes possible to simultaneously perform bending and widening of light. By widening the light not only by the projection lens 13 but also by the aspherical mirror 14, the projection lens 13 can be made smaller than when the light is widened only by the projection lens 13. The projection lens 13 and the aspherical mirror 14 perform image enlargement and image formation on the screen 16. The projection lens 13 functions to enlarge an image and form an image on the screen 16. The aspherical mirror 14 functions to enlarge an image. The aspherical mirror 14 may be appropriately deformed so that image distortion can be corrected.

  The housing 15 houses the projection engine unit 11. The casing 15 is formed with an internal dimension that allows the projection engine unit 11 to move within the casing 15. The screen 16 is a reflective screen that reflects light from the projection engine unit 11. The screen 16 can have good viewing angle characteristics by making it possible to diffuse light in a desired range where an observer exists.

  The projection engine unit 11 may be completely stored in the housing 15, or a part of the projection engine unit 11, for example, a part of the aspherical mirror 14 may be protruded from the housing 15. A mirror for bending the optical path may be provided between the projection lens 13 and the aspherical mirror 14. When the optical path is bent by about 90 degrees with a mirror, the optical engine 12 is arranged to emit light in the vertical direction or the depth direction in FIG. As a result, the entire projection engine unit 11 can be arranged at a position closer to the wall surface W.

  The projector 10 is installed on a rack K placed near the wall surface W. In addition, the projector 10 may be installed on a floor surface, a desk, a side board, or the like, for example. Since the projector 10 has a compact configuration, an installation location can be easily secured. By enabling the projector 10 to be installed near the wall surface W, a large screen can be displayed even in a narrow room.

  FIG. 3 schematically shows the optical system of the projection engine unit 11. The projection lens 13 and the aspherical mirror 14 are arranged so that their optical axes are substantially coincident. The normal line N of the screen 16 is substantially parallel to the optical axis of the projection lens 13 and the optical axis of the aspherical mirror 14. Both the projection lens 13 and the aspherical mirror 14 constitute a so-called coaxial optical system having a common optical axis AX. The projection engine unit 11 and the screen 16 constitute a so-called shift optical system in which light modulated in accordance with an image signal is shifted to a specific side with respect to the optical axis AX and travels.

  Specifically, the light modulated in accordance with the image signal is shifted to the upper side of the paper surface of FIG. 3 with respect to the optical axis AX. On the other hand, the center normal of the image plane virtually formed on the exit surface of the cross dichroic prism 24 in the optical engine 12 is parallel to the optical axis AX and opposite to a specific side, that is, light. The axis AX is shifted to the lower side in FIG. With this configuration, the projection engine unit 11 causes light having a large incident angle to enter the screen 16. The incident angle is an angle formed by the normal line N of the screen 16 and the incident light beam.

  By employing a coaxial optical system, it is possible to adopt a normal coaxial system design method. Therefore, it is possible to realize an optical system with a small number of man-hours for designing the optical system and with few aberrations. The aspherical mirror 14 may have a shape that is substantially rotationally symmetric with respect to the optical axis AX, for example, a shape obtained by cutting out a part other than the apex of the conical shape. By making the aspherical mirror 14 substantially rotationally symmetric with respect to the optical axis AX, the optical axis of the aspherical mirror 14 and the optical axes of other configurations can be easily matched. Since the aspherical mirror 14 has an axisymmetric aspherical shape, it can be processed by a simple method such as a lathe. Therefore, the aspherical mirror 14 can be manufactured easily and with high accuracy.

  The projector 10 employs a super-wide-angle optical system that uses the projection lens 13 and the aspherical mirror 14 so that the angle of view θ is at least 150 degrees, for example, 160 degrees. Furthermore, by adopting a shift optical system that uses only a part of the angle range of the ultra-wide angle, it is possible to align the light traveling direction. In this embodiment, for example, the minimum incident angle on the screen 16 is 70 degrees and the maximum incident angle is 80 degrees. By adopting the shift optical system, it is possible to make the angle difference of the light incident on the screen 16 within about 10 degrees.

4 and 5 show a simulation of the behavior of light modulated in accordance with the image signal. As shown in FIG. 4, the projection lens 13 is configured by using nine spherical lenses. A spherical lens is an optical element that transmits and deflects light. The G light spatial light modulation device 23G, the B light spatial light modulation device 23B , and the R light spatial light modulation device 23R ( not shown) ( disposed on the back side of the cross dichroic prism 24) are arranged on the optical axis AX. On the other hand, a shift optical system is realized by shifting vertically. As shown in FIG. 5, the projection lens 13 forms an image on the screen 16 with light passing through the aspherical mirror 14. Note that the configuration of the projection lens 13 is not limited to that described in the present embodiment, and any configuration capable of achieving a super wide angle may be used.

  FIG. 6 explains the adjustment of the screen size by the projector 10. The projection engine unit 11 is configured to be movable in a direction substantially orthogonal to the screens 16 and 17 that are irradiated surfaces in the housing 15. The direction substantially orthogonal to the screens 16 and 17 is a direction substantially parallel to the optical axis and along the optical path. In the state shown on the left side of the white arrow in the figure, the projector 10 displays a screen having a diagonal dimension of, for example, 45 inches on the screen 16. At this time, the projection engine unit 11 is located inside the housing 15 and on the wall surface W side. When the projection engine unit 11 is moved in a direction indicated by an arrow away from the wall surface W in the housing 15 from a state where a 45-inch screen is displayed, the state shown on the right side of the white arrow in the figure is obtained.

  In the state shown on the right side of the white arrow in the figure, the projector 10 displays a screen having a diagonal dimension of 67 inches, for example, on the screen 17. At this time, the projection engine unit 11 is in a position on the opposite side of the wall surface W in the housing 15. The screen 17 that displays a 67-inch screen is larger than the screen 16 that displays a 45-inch screen, and is arranged vertically above. When the projection engine unit 11 is moved in a direction indicated by an arrow approaching the wall surface W in the housing 15 from the state where the 67-inch screen is displayed, the projector 10 returns to the state where the 45-inch screen is displayed. In this way, the projector 10 can adjust the screen size to a 45-inch small screen and a 67-inch large screen by moving the projection engine unit 11 in the housing 15. The projector 10 of the present invention can adjust the screen size without moving the projector 10 main body.

  For example, the projection engine unit 11 can be moved automatically or manually in response to an input operation for instructing adjustment of the screen size. Since the projection engine unit 11 only needs to be able to reciprocate in the direction along the optical path, the projection engine unit 11 can be configured to move on a linear rail or along a guide, for example. In this embodiment, the case where the screens 16 and 17 having different sizes are prepared for displaying the small screen and the large screen is described. However, the small screen and the large screen are displayed on the same screen. Either may be displayed.

  FIG. 7 illustrates the relationship between the distance from the projection position where the projector 10 projects light and the screen size. The vertical axis in the graph represents the height from the projection position to the display position, and the horizontal axis represents the distance from the projection position to the display position. The distance from the projection position to the display position is a distance in a direction substantially orthogonal to the irradiated surface. In the case of 45 inches indicated by a solid line and the case of 67 inches indicated by a broken line, the distance from the projection position to the display position remains only about 100 mm. If the casing 15 is of a size that is normally used, the projection engine unit 11 can sufficiently move about 100 mm. By using an ultrashort focal length optical system, it is possible to change the screen size significantly by moving the projection engine unit 11 as long as it fits in a normal casing 15.

  In this embodiment, the maximum incident angle of light rays on the screens 16 and 17 is, for example, 80 degrees. The distance from the wall surface W to the projection position depends on the incident angle (tan θ) of the light beam. For this reason, the movement amount of the projection engine unit 11 at 45 inches and 67 inches is required to be about twice as long as the maximum incident angle is set to 80 degrees to 70 degrees. Within the normal casing 15, it is very difficult to double the amount of movement of the projection engine unit 11 from about 100 mm to about 200 mm, for example. Therefore, it is desirable for the projector 10 to make the maximum incident angle of light rays on the screens 16 and 17 as large as possible, for example, about 80 degrees or more.

  By eliminating the need for a design that incorporates a zoom function for the optical system of the projection engine unit 11, the zoom function can be easily realized without encouraging the difficulty in designing the optical system or complicating the configuration. Since the projection engine unit 11 only needs to be movable, a configuration that can be easily designed can be achieved, and the manufacturing cost can be reduced. In addition, a highly reliable and highly accurate zoom mechanism can be realized with a simple configuration. As a result, there is an effect that it is possible to easily adjust the screen size when performing proximity projection. The projector 10 is not limited to a configuration that allows the projection engine unit 11 to move in a direction substantially orthogonal to the irradiated surface. The projection engine unit 11 only needs to be movable in the direction along the optical path. For example, when the optical path is bent approximately 90 degrees by a mirror provided between the projection lens 13 and the aspherical mirror 14, the projection engine unit 11 is substantially parallel to the irradiated surface, which is a direction substantially parallel to the optical axis. It can be movable in any direction.

  For example, the projector 10 can enjoy a large screen and an appreciation according to the contents when it is desired to obtain a sense of reality such as a small screen or a movie for a normal television program. The projector 10 is not limited to adjusting the image size between 45 inches and 67 inches. The displayable image size can be appropriately set according to the configuration of the projector 10. Further, in addition to being able to switch between two types of screens having different sizes, a configuration in which switching is possible for three or more types of screens having different sizes may be adopted.

  By enabling proximity projection, the projector 10 can reduce the restriction on the installation position, and can also save space. In addition, it is possible to display a large screen even in a small room, and it is possible to reduce consideration for people entering the optical path. While video devices for home use as well as business use tend to have a large screen, a projector capable of displaying a large screen has attracted attention. If it is necessary to install the projector at a position away from the screen to some extent, the projector is installed at the center of the room if it is a small room. It is difficult to permanently fix the projector in the center of the room in the home. In addition to installing the projector every time it is used, it is also necessary to connect to an external device such as a DVD.

  With the projector 10 of the present invention, it is possible to constantly fix the projector 10 main body at a position close to the wall surface W, so that troublesome installation and connection can be reduced. Further, in the past, the projector is often installed at a position close to the observer, whereas the projector 10 of the present invention can be installed near the wall surface W and away from the observer. Is possible. By installing the projector 10 at a position away from the observer, it is possible to reduce the influence on the observer due to the heat from the lamp serving as the heat source, the rotating sound of the heat radiating fan, and the like, and a comfortable video viewing can be performed.

  8 and 9 explain the focus adjustment. When adjusting the screen size, the projector 10 needs to adjust the focus due to a change in the projection distance. It is desirable that the projection engine unit 11 is configured to be movable in the direction along the optical path and to be adjustable in focus. The two lenses 30 disposed on the aspherical mirror 14 side of the projection lens 13 are provided so as to be movable in the optical axis AX direction. The focus adjustment of the projection engine unit 11 is performed by moving the two lenses 30. The lens 30 is a spherical lens and is an optical element that transmits and deflects light. Regarding the lenses other than the two lenses 30 in the projection lens 13, the relative positional relationship with the aspherical mirror 14 is always constant.

  For example, when a 57-inch screen is displayed, two lenses 30 are arranged at a position on the aspherical mirror 14 side of the projection lens 13 as shown above the white arrow in FIG. By arranging the two lenses 30 at such positions, an image is formed on the screen 18 that displays a 57-inch screen, as illustrated on the left side of the white arrow in FIG. In this way, focus adjustment is performed on a 57-inch screen.

  Next, assume that the screen size is adjusted to 91 inches. At this time, the two lenses 30 are moved in the direction indicated by the arrow moving away from the aspherical mirror 14. Then, as shown below the white arrow in FIG. 8, the two lenses 30 are moved to a position close to the other lens 31 adjacent to the two lenses 30 in the projection lens 13. By moving the two lenses 30 to such a position, an image is formed on the screen 19 displaying a 91-inch screen, as illustrated on the right side of the white arrow in FIG. In this way, focus adjustment is performed on a 91-inch screen. When the screen size is adjusted to 57 inches again, focus adjustment is performed by moving the two lenses 30 in the direction indicated by the arrow approaching the aspherical mirror 14.

  By adjusting the focus as well as adjusting the screen size, a high-quality image can be displayed each time the screen size is adjusted. The two lenses 30 can be moved automatically or manually according to an input operation for instructing focus adjustment, for example. Further, the focus adjustment may be automatically performed simultaneously with the adjustment of the screen size by making the two lenses 30 movable in conjunction with the movement of the projection engine unit 11 for adjusting the screen size.

  The projection engine unit 11 is not limited to the configuration in which the focus adjustment is performed by moving the two lenses 30 arranged on the aspherical mirror 14 side of the projection lens 13. Any structure may be used as long as it moves at least one optical element arranged on the aspherical mirror 14 side of the projection lens 13. By adopting a configuration in which the lens arranged on the aspherical mirror 14 side of the projection lens 13 is moved, focus adjustment can be performed with a simple configuration that can be easily designed. Furthermore, it is only necessary that at least one of the lenses constituting the projection lens 13 can be moved. For example, a configuration may be adopted in which a lens other than the lens disposed on the aspherical mirror 14 side is moved.

  The projector 10 is not limited to a configuration that projects light from below the irradiated surface. The projector 10 may be configured to project light from above the irradiated surface. When projecting light from above the irradiated surface, the projector 10 is arranged upside down from the state shown in FIG. When projecting light from above the surface to be irradiated, the projector 10 may be installed, for example, suspended from the ceiling surface of the room. Since the projector 10 of the present invention can eliminate the need for movement once installed, the projector 10 can be permanently fixed on the ceiling surface and can realize a zoom function. The projector 10 may be configured to have at least a zoom function, and the focus adjustment function may be omitted.

  FIG. 10 shows a schematic configuration of the projection engine unit 40 according to the second embodiment of the present invention. The projection engine unit 40 of the present embodiment can be applied to the projector 10 (see FIG. 1). The projection engine unit 40 of this embodiment has four aspherical mirrors 41, 42, 43, and 44. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. The aspherical mirrors 41, 42, 43, and 44 are mirrors having aspherical curved surfaces. The projection engine unit 40 constitutes a so-called decentered optical system that does not have a common optical axis.

The light from the optical engine 12 is reflected by the respective aspherical mirrors 41, 42, 43, and 44 and then enters a screen (not shown). The fourth aspherical mirror 44 that reflects the light that has passed through the three aspherical mirrors 41, 42, and 43 is a wide-angle reflecting unit that widens the light most among the aspherical mirrors 41, 42, 43, and 44. And, it has the same function as the aspherical mirror 14 (see FIG. 3) in the first embodiment.

  The projection engine unit 40 adjusts the screen size by moving in the direction along the optical path, similarly to the projection engine unit 11 (see FIG. 1) of the first embodiment. Further, the projection engine unit 40 performs focus adjustment by moving the aspherical mirror 43 that reflects light in front of the fourth aspherical mirror 44 in the forward and backward directions indicated by the double arrows in the drawing. Thereby, also in the present embodiment, a high-quality image can be displayed every time the screen size is adjusted.

  The projection engine unit 40 may be configured to perform focus adjustment by moving at least one of the four aspherical mirrors 41, 42, 43, and 44. Further, the projection engine unit 40 is not limited to the configuration having the four aspherical mirrors 41, 42, 43, and 44, and may be any configuration having a plurality of mirrors. In this case, the projection engine unit 40 can be configured to allow focus adjustment by making at least one of the plurality of mirrors movable.

  The projector 10 includes a scanning unit such as a galvanometer mirror as an image forming unit instead of the image forming unit in the above-described embodiment, and projects an image onto a projection surface by scanning a laser beam from a light source. It may be a type of projector. The projector may be a so-called rear projector that supplies light to one surface of the screen and observes an image by observing light emitted from the other surface of the screen.

  As described above, the projector according to the present invention is suitable for close-up projection.

1 is a diagram illustrating a schematic configuration of a projector according to a first embodiment of the invention. The figure which shows schematic structure of an optical engine. The figure which represented typically the optical system of the projection engine part. The figure which shows the simulation of the behavior of the light modulated according to the image signal. The figure which shows the simulation of the behavior of the light modulated according to the image signal. The figure explaining adjustment of the image size by a projector. The figure explaining the relationship between the distance from a projection position, and image size. The figure explaining focus adjustment. The figure explaining focus adjustment. FIG. 6 is a diagram illustrating a schematic configuration of a projection engine unit according to a second embodiment of the invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Projector, 11 ... Projection engine part, 12 ... Optical engine, 13 ... Projection lens, 14 ... Aspherical mirror, 15 ... Housing, 16 ... Screen, K ... Rack, W ... Wall surface, 21R ... Red (R) light LED, 21G ... Green (G) light LED, 21B ... Blue (B) light LED, 22 ... Collimator lens, 23R ... R light spatial light modulator, 23G ... G light spatial light modulator, 23B ... Spatial light modulator for B light, 24 ... cross dichroic prism, 25 ... first dichroic film, 26 ... second dichroic film, AX ... optical axis, N ... normal, 17, 18, 19 ... screen, 30, 31 ... Lens, 40 ... projection engine unit, 41, 42, 43, 44 ... aspherical mirror.

Claims (9)

An optical engine that emits light emitted from a light source and modulated in accordance with an image signal, a projection lens that projects light emitted from the optical engine, and a wide-angle reflecting unit that widens the angle of light from the projection lens by reflection A projection engine unit comprising:
A housing that houses the projection engine unit,
The projection lens and the wide-angle reflection part are arranged so that their optical axes substantially coincide with each other, and shift light to a specific side with respect to the optical axis,
The projection engine unit is capable of moving integrally with the optical engine, the projection lens, and the wide-angle reflection unit in a direction along the optical axis in the casing. The projector according to claim 1, wherein the direction along the optical axis is a direction substantially perpendicular to the irradiated surface. The maximum incident angle at which the light projected from the projection engine enters the irradiated surface is:
The projector according to claim 1, wherein the projector is at least 75 degrees and at most 80 degrees. The projector according to claim 1, wherein the optical engine is shifted in a direction perpendicular to the optical axis.   The projector according to claim 1, wherein the projection engine unit is configured to be adjustable in focus. The projection lens includes a plurality of optical elements , and at least one of the plurality of optical elements is movable relative to the projection engine unit in a direction along the optical axis. The projector according to claim 5. The projector according to claim 6, wherein at least one of the plurality of optical elements disposed on the wide-angle reflection part side is movable. The projector according to claim 5, wherein the projection engine unit includes a plurality of mirrors, and at least one of the plurality of mirrors is movable. The projection engine unit, the projector according to any one of claims 1-8, characterized in that it comprises a spatial light modulator that modulates in accordance with an image signal light from the light source unit.

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