KR20080048408A - Projector - Google Patents

Abstract

A projector is provided to easily control the projected image size of the projector during short-distance projection without utilizing a projection lens. A projector(10), performing short-distance projection having a gap about several centimeters a screen(16), includes a projection engine part(11). The projection engine part projects light to the screen, where the projected light is modulated according to image signals before projection. The projection engine part includes an optical engine(12), a projection lens(13), and an aspherical mirror(14), and moves on a predetermined path for changing projection distance in order to control projection size. The optical engine includes RGB(Red, Green, and Blue) light sources. The aspherical mirror reflects and folds the light from the projection lens and transmits to the screen.

Description

Projector {PROJECTOR}

The present invention relates to a technology of a projector, in particular a projector capable of close projection that projects light from a position close to the irradiated surface.

Most of the projectors of the front projection type that are spread in the past are installed at a position away from the screen to some extent in order to secure the projection distance. When the projector is installed at a position away from the screen, it is necessary to secure a place such that no obstacles obstruct the light in the light path from the projector to the screen. The restriction of the installation position of such a projector becomes remarkable as the display screen becomes larger. In particular, it is difficult to display a large screen in a narrow room. In addition, while displaying an image, consideration is also required such that a person does not enter or exit the light path.

In recent years, the technique of performing near projection by the front projection type projector is proposed. By enabling proximity projection, it becomes possible to place the projector at a position close to the wall surface, for example. By allowing the projector to be disposed at a position close to the wall, for example, within a few tens of centimeters from the wall, the restriction on the installation position of the projector can be reduced, and space can be saved. In addition, the display of the large screen can be made possible even in a narrow room, and consideration for the entry and exit of a person in the light path can be reduced. An ultra short focus optical system is adopted as a projector for performing near projection. The ultra-short focus optical system makes it possible to display a large screen with a short throw distance. In order to realize ultra short focus, an optical element that greatly widens light is required. In order to widen the angle using only an optical element that transmits light, such as a lens, enormous cost is required. On the other hand, in the technique proposed in Patent Document 1, for example, ultra short focus is realized by a combination of only aspherical mirrors.

[Patent Document 1] Japanese Patent Application Laid-Open No. 2002-40326

Most of the projectors of the front projection type that are conventionally supplied are equipped with a zoom function for adjusting the screen size. In general, the zoom function of the projector is realized by adjusting the position of the optical elements constituting the optical system. In the case of an ultra short focus optical system such as the configuration proposed in Patent Literature 1, very high difficulty is required only for a design that enables a large wide angle. For this reason, the design which further includes a zoom function in the structure which enables big wide angle angle becomes very difficult. Even if the design including the zoom function is possible, the configuration is complicated and the cost is significantly higher. From such a situation, most of the projectors equipped with the ultra short focus optical system, such as the structure proposed in Patent Document 1, will secure 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 constant installation of the projector may be restricted. As described above, there is a problem that it is difficult to realize a configuration in which the proximity projection is enabled and the screen size can be easily adjusted. SUMMARY OF THE INVENTION The present invention has been made in view of the above problem, and an object thereof is to provide a projector capable of easily adjusting the screen size when performing close projection.

In order to solve the above problems and achieve the object, according to the present invention, there is provided a light source unit and an image forming unit for displaying an image having a desired size on an irradiated surface by using light from the light source unit. A projection engine unit for projecting light onto an irradiated surface and a housing accommodating the projection engine unit can be provided, and the projection engine unit can provide a projector which is movable in a direction along an optical path in the housing.

By changing the projection distance by moving the projection engine unit, the screen size can be adjusted. By moving the projection engine unit into the housing, movement of the projector once installed can be made unnecessary. Therefore, it is possible to realize the constant fixing of the projector and the zoom function. In particular, in the case of using an ultra short focus optical system, it is possible to significantly change the screen size even if the projection engine portion is moved to a degree accommodated in a normal housing. By eliminating the design including the zoom function for the optical system of the projection engine unit, the zoom function can be easily realized without increasing the difficulty of the design of the optical system and the complexity of the configuration. Since the projection engine unit can be moved, a configuration that can be easily designed can be achieved, and manufacturing cost can be reduced. In addition, a simple structure can realize a zoom mechanism with high reliability and high density. In this way, a projector can be obtained in which the screen size can be easily adjusted in the case of performing proximity projection.

Moreover, as a preferable aspect of this invention, it is preferable that an image forming part has the wide-angle reflecting part which makes light angle wide by reflection. As a result, it is possible to achieve a large wide angle of light and to have a configuration capable of close projection.

Moreover, as a preferable aspect of this invention, it is preferable that an image formation part has a projection lens, and the wide angle reflection part widens the light from a projection lens. The projection lens forms an image on the irradiated surface and widens the light. The wide angle reflector greatly widens the light from the projection lens. As a result, it is possible to obtain a configuration in which proximity projection is possible.

Moreover, as a preferable aspect of this invention, it is preferable that the projection lens and the wide-angle reflecting part are arrange | positioned so that an optical axis may substantially correspond, and it will shift light to a specific direction with respect to an optical axis. By shifting the light from the optical axis to a specific side, it becomes possible to match the traveling direction of the light to achieve a large incident angle with respect to the irradiated surface. In this way, proximity projection can be performed.

Moreover, as a preferable aspect of this invention, it is preferable that the projection engine part is comprised so that focus adjustment is possible. In the case of adjusting the screen size, it is necessary to adjust the focus by changing the projection distance. Accordingly, a high quality image can be displayed whenever the screen size is adjusted.

Moreover, as a preferable aspect of this invention, the projection engine part has a projection lens provided with a some optical element, and the wide-angle reflecting part which widens the light from a projection lens, and at least one of the optical elements which comprise a projection lens is an optical axis It is preferable to be movable with respect to the direction. Thereby, the structure which can adjust focus can be set.

Moreover, as a preferable aspect of this invention, it is preferable that at least 1 optical element arrange | positioned at the wide angle reflection part side among optical elements is movable. Thereby, focus adjustment can be performed easily by a design and a simple structure.

Moreover, as a preferable aspect of this invention, it is preferable that an image forming part has a some mirror, and at least one of a mirror is movable. Thereby, the structure which can adjust focus can be set.

Moreover, as a preferable aspect of this invention, it is preferable that an image forming part has the spatial light modulator which modulates the light from a light source part according to an image signal. In the case where 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 displayed on an irradiated surface easily.

Moreover, as a preferable aspect of this invention, it is preferable that a light source part injects a laser beam, and the image formation part has a scanning means which displays an image on an irradiated surface by scanning the laser beam from a light source part. When displaying an image on the irradiated surface by scanning the laser light from the light source unit by the scanning means, the light source unit should be adjusted in accordance with the image signal, but the image can be displayed without using the projection lens. Thereby, an image can be displayed on an irradiated surface easily.

According to the present invention, an object of the present invention is to provide a projector in which the screen size can be easily adjusted in the case of proximity projection.

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

(Example 1)

1 shows a schematic configuration of a projector 10 according to a first embodiment of the present invention. The projector 10 is a front projection type projector that projects light in accordance with an image signal. The projector 10 performs close projection from a position close to the irradiated surface, for example, a position of 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 as the irradiated surface. The projection engine unit 11 has 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 movable integrally by moving the projection engine unit 11.

2 shows a schematic configuration of an optical engine 12. The red (R) light LED 21R, which is a solid light source, is a light source unit that supplies R light. The R light from the red (R) light LED 21R is parallelized by the collimator lens 22 and then enters into the spatial light modulator 23R for R light. The spatial light modulator 23R for R light is a spatial light modulator that modulates R light in accordance with an image signal, and is a transmissive liquid crystal display device. The R light modulated by the 23-R spatial light modulator 23R enters the cross dichroic prism 24 which is a color synthesizing optical system.

The green (G) light LED 21G as a solid light source is a light source unit for supplying G light. The G light from the green (G) light LED 21G is incident on the spatial light modulator 23G for G light after being parallelized by the collimator lens 22. The G-light spatial light modulator 23G is a spatial light modulator 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 is incident on the cross dichroic prism 24 from the other side of the R light.

The blue (B) light LED 21B, which is a solid light source, is a light source unit for supplying B light. The B light from the blue (B) light LED 21B is parallelized by the collimator lens 22 and then enters into the B light spatial light modulator 23B. The B-light spatial light modulator 23B is a spatial light modulator that modulates B light in accordance with an image signal, and is a transmissive liquid crystal display device. The B light modulated by the B-light spatial light modulator 23B is incident on the cross dichroic prism 24 from the other of the R light and the G light. In addition, the optical engine 12 may be configured to use a homogenizing optical system, for example, a rod integrator, a fly's eye lens, or a superimposed lens, which makes the intensity distribution of the light beam uniform.

The cross dichroic prism 24 has two first dichroic films 25 and second dichroic films 26 disposed 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, the G light, and the B light respectively incident from the other side, and emits them in the direction of 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 (LCOS), a digital micromirror device (DMD), a grating light valve (GLV), or the like may be used. The projector 10 is not limited to the structure provided with the spatial light modulator for every color light. The projector 10 may be configured to modulate two or three color lights by one spatial light modulator. In addition, the optical engine 12 is not limited to the case where LED is used as a light source part. As a light source part, you may use solid-state light sources other than LED, such as a laser light source, and lamps, such as an ultrahigh pressure mercury lamp, for example.

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 portion 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 to advance 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 for red (R) light as a light source part. An image forming unit for projecting and displaying an image of a desired size on the screen 16 as an irradiated surface by using light from the LED 21R, the green (G) light LED 21G, and the blue (B) light LED 21B. to be. 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 layer of a highly reflective member, for example, a layer of a metal member such as aluminum, a dielectric multilayer film, or the like can be used. In addition, a protective film having a transparent member may be formed on the reflective film.

The aspherical mirror 14 has a curved shape, which makes it possible to simultaneously bend light and wide angle. 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 the case where 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 to form an image on the screen 16. The aspherical mirror 14 functions to enlarge the image. The aspherical mirror 14 may be appropriately deformed so as to correct distortion of the image.

The housing 15 houses the projection engine unit 11. The housing 15 is formed to have an internal dimension such that the projection engine unit 11 is movable within the housing 15. The screen 16 is a reflective screen that reflects light from the projection engine unit 11. The screen 16 can be made to have a favorable viewing angle characteristic by making it possible to diffuse light in the desired range in which an observer exists.

In addition to completely storing the projection engine unit 11 in the housing 15, a part of the projection engine unit 11, for example, a part of the aspherical mirror 14, may be pushed out of the housing 15. A mirror for bending the optical path may be provided between the projection lens 13 and the aspherical mirror 14. In the case where the mirror is bent at an approximately 90 degree light path, the optical engine 12 is arranged to emit light in the vertical direction or the depth of the ground of FIG. 1. Thereby, it becomes possible to arrange | position the whole projection engine part 11 in the position closer to the wall surface W. FIG.

The projector 10 is provided on the rack K placed close to the wall surface W. As shown in FIG. In addition, the projector 10 may be provided, for example, on a floor, a desk, a sideboard, or the like. Since the projector 10 has a compact structure, the installation place can be easily secured. By allowing the projector 10 to be installed near the wall W, a large screen can be displayed even in a narrow room.

3 schematically shows the optical system of the projection engine unit 11. The projection lens 13 and the aspherical mirror 14 are disposed so that the optical axes approximately coincide. 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. The projection lens 13 and the aspherical mirror 14 both constitute a so-called coaxial optical system having a common optical axis AX. In addition, the projection engine unit 11 and the screen 16 constitute a so-called shift optical system which shifts the light modulated according to the image signal to a specific direction with respect to the optical axis AX.

Specifically, the light modulated in accordance with the image signal is shifted upward with respect to the optical axis AX to the paper surface in FIG. 3. 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 the specific side, that is, with respect to the optical axis AX. It shifts below the paper surface in FIG. With this configuration, the projection engine unit 11 causes light having a large incident angle to be incident on 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 employ a design method of a normal coaxial system. Therefore, it is possible to realize an optical system with a small number of design steps and a small aberration. The aspherical mirror 14 can be made into a shape which is substantially rotationally symmetrical with respect to the optical axis AX, for example, a portion other than the vertex portion among the conical shapes. By setting the aspherical mirror 14 to a shape that is substantially rotationally symmetric with respect to the optical axis AX, it becomes possible to easily match the optical axis of the aspherical mirror 14 with an optical axis having a different configuration. Since the aspherical mirror 14 has an aspherical symmetrical aspherical shape, the aspherical mirror 14 can be processed by a simple method such as a lathe. Therefore, the aspherical mirror 14 can be manufactured easily and with high precision.

The projector 10 employs an ultra wide-angle optical system in which the angle of view θ is at least 150 degrees, for example, 160 degrees, by using the projection lens 13 and the aspherical mirror 14. In addition, by adopting a shift optical system that uses only a part of the angular range of the ultra wide angle, it is possible to match the traveling direction of the light. In the present embodiment, for example, the minimum incident angle on the screen 16 is 70 degrees, and the maximum incident angle is 80 degrees. By employing the shift optical system, the angle difference of the light incident on the screen 16 can be made within about 10 degrees.

4 and 5 show simulations of the behavior of light modulated according to the image signal. As shown in FIG. 4, the projection lens 13 is comprised using nine spherical lenses. Spherical lenses are optical elements that transmit and deflect light. The G-light spatial light modulator 23G and the B-light spatial light modulator 23B (the R-light spatial light modulator 23R (not shown) are disposed inside the cross dichroic prism 24.) The shift optical system is realized by vertically shifting the optical axis AX. As shown in FIG. 5, the projection lens 13 forms an image on the screen 16 by light passing through the aspherical mirror 14. In addition, the structure of the projection lens 13 is not limited to what is demonstrated in this embodiment, What is necessary is just a structure which can be super wide-angled.

6 illustrates adjustment of the screen size by the projector 10. The projection engine part 11 is comprised so that the movement in the housing 15 with respect to the direction substantially orthogonal to the screen 16 and 17 which is an irradiated surface is possible. The direction substantially orthogonal to the screens 16 and 17 is a direction substantially parallel to the optical axis and is a direction along the optical path. When it is in the state shown to the left of the white arrow in the figure, the projector 10 is displaying a screen on the screen 16, for example, having a diagonal dimension of 45 inches. At this time, the projection engine part 11 is located in the housing 15 at the wall surface W side. When the projection engine unit 11 is moved in the housing 15 in the direction indicated by the arrow away from the wall surface W from the state displaying the 45-inch screen, the state shown on the right side of the white arrow is shown in the figure.

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

The projection engine unit 11 can be moved automatically or manually, for example, in accordance with an input operation for instructing adjustment of the screen size. Since the projection engine part 11 should just be able to reciprocate with respect to the direction along an optical path, it can be set as the structure which moves so that it may follow a linear rail or a guide, for example. In addition, in the present embodiment, the case where screens 16 and 17 of different sizes are prepared when displaying a small screen and when displaying a large screen is described. You may also

7 illustrates the relationship between the distance from the projection position at which the projector 10 projects the light and the screen size. In the graph, the vertical axis 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 to a direction approximately perpendicular to the irradiated surface. In the case of 45 inches represented by the solid line and 67 inches represented by the broken line, the distance from the projection position to the display position remains about 100 mm. If it is the housing 15 of the size normally used, the movement of about 100 mm of the projection engine part 11 is fully possible. By using the ultra short focus optical system, it is possible to greatly change the screen size by the movement of the projection engine unit 11 of the degree accommodated in the ordinary housing 15.

In this embodiment, the incident maximum angle of the light beams on the screens 16 and 17 is, for example, 80 degrees. The distance from the wall W to the projection position depends on the angle of incidence tanθ of the light beam. For this reason, the movement amount of the projection engine part 11 in 45 inches and 67 inches is required to be about twice as long if the incidence maximum angle is 80 to 70 degrees. If it is in the normal housing 15, it is very difficult to double the movement amount of the projection engine part 11 from about 100 mm to about 200 mm, for example. Therefore, it is preferable that the projector 10 be as large as possible, for example, about 80 degrees or more, as long as the maximum angle of incidence of the light rays on the screens 16 and 17 can be achieved.

By eliminating the design including the zoom function for the optical system of the projection engine unit 11, the zoom function can be easily realized without increasing the difficulty of the design of the optical system and the complexity of the configuration. Since the projection engine part 11 should be made movable, it can be set as the structure which can be designed easily, and manufacturing cost can be reduced. In addition, a simple structure can realize a zoom mechanism with high reliability and high density. This brings about the effect of enabling easy adjustment of the screen size in the case of proximity projection. The projector 10 is not limited to the structure which enables the projection engine part 11 to move with respect to the direction orthogonal to a to-be-irradiated surface. The projection engine unit 11 may be movable with respect to 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 arranged on an irradiated surface that is a direction substantially parallel to the optical axis. It can be made to move about a substantially parallel direction.

The projector 10 makes it possible, for example, to enjoy a large screen and a contemplation according to content when it is desired to obtain a sense of presence such as a small screen or a movie for a normal television program. In addition, the projector 10 is not limited to the case where the image size is adjusted between 45 inches and 67 inches. The displayable image size can be appropriately set according to the configuration of the projector 10. In addition to being able to switch between two screens of different sizes, a configuration capable of switching to three or more types of screens of different sizes may be used.

By enabling the proximity projection, the projector 10 can reduce the restriction on the installation position, and the space can be saved. In addition, the display of the large screen can be made possible even in a narrow room, and consideration for the entry and exit of a person in the light path can be reduced. Projectors that can display a large screen have attracted attention as a trend toward large screens not only for work but also for home video equipment. If you need to install the projector at some distance from the screen, in a narrow room you will install the projector in the center of the room. It is difficult to constantly fix the projector in the center of the room in the home. In addition to the installation of the projector, the installation of the projector is required, and the connection with an external device such as a DVD is also required.

In the projector 10 of the present invention, since the main body of the projector 10 can be fixed at a position close to the wall surface W at all times, the trouble of installation and connection can be reduced. In addition, while the projector is often installed at a position close to the observer in the related art, the projector 10 of the present invention can be installed at a position away from the observer while being near the wall W. By providing the projector 10 at a position away from the observer, the influence of the observer due to the heat from the lamp serving as the heat source, the rotational sound of the heat radiating fan, or the like can be reduced, and a comfortable video observation can be performed.

8 and 9 illustrate focus adjustment. When the projector 10 adjusts the screen size, it is necessary to adjust the focus by the change in the projection distance. It is preferable that the projection engine part 11 is comprised so that a movement with respect to the direction along an optical path is possible, and focus adjustment is possible. Two lenses 30 disposed on the aspherical mirror 14 side of the projection lens 13 are provided to be movable with respect to the optical axis AX direction. Focus adjustment of the projection engine unit 11 is performed by moving these two lenses 30. The lens 30 is a spherical lens and is an optical element that transmits and deflects light. For the lenses other than these two lenses 30 of 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 disposed at positions 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 in this position, an image is formed on the screen 18 displaying a 57-inch screen, as illustrated to the left of the white arrow in FIG. In this way, focus adjustment is performed on the 57-inch screen.

Next, the screen was resized to 91 inches. At this time, the two lenses 30 are moved in the direction indicated by the arrows away from the aspherical mirror 14. 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 of the projection lens 13. By moving the two lenses 30 in this position, an image is formed on the screen 19 displaying a 91-inch screen, as illustrated to the right of the white arrow in FIG. In this way, focus adjustment is performed on the 91-inch screen. When the screen size is adjusted to 57 inches again, the focus adjustment is made by moving the two lenses 30 in the direction indicated by the arrow approaching the aspherical mirror 14.

By performing the focus adjustment together with the adjustment of 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, for example, in accordance with an input operation to instruct focus adjustment. In addition, the two lenses 30 may be moved in conjunction with the movement of the projection engine 11 for adjusting the screen size, so that the focus adjustment may be automatically performed at the same time as the screen size.

The projection engine part 11 is not limited to the structure which performs focus adjustment by moving two lenses 30 arrange | positioned at the aspherical mirror 14 side among the projection lenses 13. What is necessary is just a structure which moves the lens which is at least 1 optical element arrange | positioned at the side of the aspherical mirror 14 among the projection lenses 13. By setting the lens arranged on the aspherical mirror 14 side of the projection lens 13, the focus adjustment can be easily designed and made possible by a simple structure. In addition, at least one of the lenses constituting the projection lens 13 may be moved. For example, it is good also as a structure which moves lenses other than the lens arrange | positioned at the aspherical mirror 14 side.

The projector 10 is not limited to the structure which projects light from under the irradiation surface. The projector 10 may be configured to project light from above the irradiated surface. When projecting light from above the surface to be irradiated, the projector 10 is arranged upside down from the state shown in FIG. When the light is projected from the upper side of the irradiated surface, the projector 10 may be provided to be suspended from the ceiling surface of the room, for example. Since the projector 10 of the present invention can be made unnecessary to move after being installed once, the projector 10 can be fixed at the ceiling and can realize a zoom function. The projector 10 may be a structure having at least a zoom function, and the focus adjustment function may be omitted.

(Example 2)

10 shows a schematic configuration of a 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) described above. The projection engine unit 40 of the present embodiment is characterized by having four aspherical mirrors 41, 42, 43, 44. The same reference numerals are given to the same parts as in the first embodiment, and redundant descriptions are omitted. The aspherical mirrors 41, 42, 43, 44 are mirrors having aspherical curved surfaces. The projection engine unit 40 constitutes a so-called eccentric optical system that does not have a common optical axis.

The light from the projection engine unit 40 is reflected by each aspherical mirror 41, 42, 43, 44, and then enters a screen not shown. The fourth aspherical mirror 44 that reflects light passing through the three aspherical mirrors 41, 42, 43 is a wide angle reflecting part that widens the most light among the aspherical mirrors 41, 42, 43, 44. 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 as in the projection engine unit 11 (see FIG. 1) of the first embodiment. In addition, the projection engine unit 40 adjusts the focus by moving the aspherical mirror 43 that reflects light in front of the fourth aspherical mirror 44 back and forth indicated by both arrows in the figure. Accordingly, even in this embodiment, a high quality image can be displayed whenever 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. In addition, the projection engine part 40 should not be limited to the structure which has four aspherical mirrors 41, 42, 43, and 44, It should just be a structure which has a some mirror. In this case, the projection engine unit 40 may be configured such that focus adjustment is possible by moving at least one of the plurality of mirrors.

The projector 10 has scanning means such as a galvano mirror as an image forming unit instead of the image forming unit in the above-described embodiment, and projects an image onto the projected surface by scanning a laser beam from a light source. It is good also as a laser scan type projector. The projector may be a so-called rear projector that supplies light to one side of the screen and views the image by observing light emitted from the other side of the screen.

As mentioned above, the projector which concerns on this invention is suitable for the case of performing near-projection.

1 is a diagram showing a schematic configuration of a projector according to Embodiment 1 of the present invention;

2 is a diagram showing a schematic configuration of an optical engine;

3 is a diagram schematically showing an optical system of a projection engine unit;

4 shows a simulation of the behavior of light modulated according to an image signal;

5 shows a simulation of the behavior of light modulated according to an image signal;

6 is a diagram for explaining adjustment of an image size by a projector;

7 is a diagram for explaining the relationship between the distance from the projection position and the image size;

8 is a diagram for explaining focus adjustment;

9 is a diagram for explaining focus adjustment;

10 is a diagram showing a schematic configuration of a projection engine unit according to Embodiment 2 of the present invention.

Explanation of the sign

10 projector 11 projection engine unit

12 optical engine 13 projection lens

14 aspheric mirror 15 housing

16: screen K: rack

W: Wall 21R: Red (R) light LED

21G: Green (G) light LED 21B: Blue (B) light LED

22: collimator lens 23R: spatial light modulator for R light

23G: Spatial light modulator for G light 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 (10)

A projection engine unit having a light source unit and an image forming unit for displaying an image having a desired size on an irradiated surface by using light from the light source unit, and a projection engine unit for projecting light according to an image signal onto the irradiated surface; A housing accommodating the projection engine With The projection engine unit is movable in the housing along a direction along an optical path. Projector characterized by. The method of claim 1, And the image forming portion has a wide angle reflecting portion that widens light by reflection. The method of claim 2, The image forming portion has a projection lens, Wherein the wide angle reflector widens the light from the projection lens. Projector characterized by. The method of claim 3, wherein And the projection lens and the wide-angle reflecting portion are arranged so that their optical axes are substantially coincident with each other, and shift light toward a specific direction with respect to the optical axis. The method according to any one of claims 1 to 4, And the projection engine unit is configured to adjust focus. The method of claim 5, wherein The image forming unit has a projection lens including a plurality of optical elements and a wide angle reflecting unit for widening the light from the projection lens, and at least one of the optical elements constituting the projection lens is movable with respect to the optical axis direction. Projector characterized in that. The method of claim 6, At least one optical element of the optical element disposed on the side of the wide-angle reflector is movable. The method of claim 5, wherein And the image forming unit has a plurality of mirrors, at least one of which is movable. The method of claim 3, wherein And the image forming unit has a spatial light modulator for modulating light from the light source unit in accordance with an image signal. The method of claim 1, The light source unit emits laser light, Said image forming portion having scanning means for displaying an image on an irradiated surface by scanning laser light from said light source portion Projector characterized by.

Images