Patent Application
20100328622
The present invention relates to cabinet structures of a projection display apparatus.
In a projection display apparatus, light from the light source is modulated into imaging light and the imaging light is reflected using a mirror and then projected on a screen where images are displayed. A conventional projection display apparatus is configured with a bottom cabinet on which a light source and an optical engine are mounted, a rear cover supported by the bottom cabinet, a mirror that is attached to the rear cover and reflects imaging light from the optical engine, a screen on which the imaging light reflected by the mirror, and a front cover on which the screen is mounted (refer to Japanese Unexamined Patent Application Publication No. 2008-76901 (page 9, FIG. 5), which is thereafter called Patent Document 1). Another conventional projection display apparatus is such that a light source and an optical unit are disposed in a bottom frame, and light emitted upwardly through the apparatus from the optical unit is reflected by a projection mirror supported by a top frame and then projected toward a screen held by a structure including the bottom frame, a left-hand and a right-hand frames, and the top frame (refer to Japanese Unexamined Patent Application Publication No. 2007-183301 (page 5, FIG. 5), which is thereafter called Patent Document 2).
A problem with Patent Document 1 above is that because the bottom cabinet holds the optical engine, the relative positional relationship between the optical engine and the mirror held by the rear cover or the screen held by the front cover, is likely to vary, and misregistration in an on-screen image tends to occur. Another similar problem with Patent Document 2 above is that because a bottom frame holds an optical unit, the relative positional relationship between the optical unit and a projection mirror held by a top frame or a screen held by a structure, is likely to vary, and misregistration in an on-screen image tends to occur.
The present invention is directed to overcome the above-described problems and the object thereof is to provide a projection display apparatus capable of preventing misregistration in an on-screen image.
A projection display apparatus according to the present invention includes a light source that emits light, an optical engine that modulates light emitted from the light source, a screen on which light emitted from the optical engine is projected, a main frame assembly that holds the optical engine and the screen, and a bottom frame that supports the main frame assembly.
Another projection display apparatus according to the present invention includes a light source that emits light; an optical engine that modulates light emitted from the light source; a screen on which light emitted from the optical engine is projected; and a main frame assembly including a holding frame that holds the optical engine, a screen frame that is connected to the holding frame and holds the screen, and a rear frame that is connected to the holding frame and the screen frame, wherein the upper end portion of the screen frame is connected with a first end portion of the rear frame, a second end portion of the rear frame is connected with the upper end portion of the holding frame, and the lower end portion of the holding frame is connected with the lower end portion of the screen frame.
A projection display apparatus according to the present invention allows misregistration in an on-screen image to be avoided. These and other objects of the present invention will be better understood by reading the following detailed description in combination with the attached drawings of a preferred embodiment of the invention.
Embodiment 1 of the present invention will be described referring to the foregoing figures.
A light source unit 101 is configured with three laser generators that emits light of three colors, red, blue and green; three laser beams each of a different wavelength are emitted from the light source unit 1 to the optical engine 2. The dichroic prism 201 of the optical engine 2 is combination means that combines together the three laser beams from the light source unit 1. The mixing rod 202 is an intensity uniformization element that uniformizes intensity distribution of the laser beams combined using the dichroic prism 201. The DMD 203 is modulation means that provides information by space modulating the laser beams uniformized using the mixing rod 202, based on imaging signals supplied from an external unit. The reflective mirror 204 reflects the laser beams modulated using the DMD 203 toward the nonplanar mirror 205 that in turn reflects to the top mirror 3 the laser beams reflected by the reflective mirror 204. Since a reflection surface of the nonplanar mirror 205 is formed so that the reflected beams may be collected and thereafter diffuse, the divergence angle of the laser beams to be reflected can be increased. The top mirror 3, which is disposed at a position higher than the optical engine 2, reflects toward the screen 4 the light emitted upwardly from the optical engine 2. The laser beams reflected by the top mirror 3 are projected onto the screen 4, whereby images corresponding to imaging signals supplied to the DMD 203 are displayed on the screen 4.
Referring to
The rear frame 6, which is trapezoid-shaped, is screw-secured to both end portions of the upper side of the rectangular screen frame 5. The holding frame 7 is configured with two holding members 71 of rectangular solid shape—which are left-right symmetrically disposed on the rear side of the screen 4, and extend vertically—and a connecting member 72 that connects the two holding members 71 together. The two holding members 71 are screw-secured at their upper end portions to the rear frame 6, and at their lower end portions to the lower side of the screen frame 5. In this manner, the screen frame 5, the rear frame 6, and the holding frame 7 are secured to each other by screws. Here, the light source unit 1 and the optical engine 2 are attached to the connecting member 72.
The rear frame 6 holding the top mirror 3 is placed at a slant, in a rear-to-front direction, from the upper portion over to the lower portion of the cabinet using the holding frame 7. This arrangement allows the holding frame 7 to bear the load of the top mirror 3 and to play a role of a supporting stick. As a result, the moment to be created on the screen frame 5 to which the rear frame 6 is attached, and the moment of the rear frame 6 per se can be reduced. The screen frame 5, the rear frame 6, and the holding frame 7, constituting the main frame assembly 11, are each formed of an aluminum material for the sake of achieving light weight.
As shown in
The projection display apparatus can be placed on a base such as a low board, with the bottom members 20a of the bottom frame 20 serving as the bearing surface as shown in
Since each of the two column members 20b has the slanted sub-member 20e, the connecting structure formed by the bottom frame 20 and the main frame assembly 11 is a pentagon, as viewed from the side, that is shaped by a closed line extending from the lower connecting portion 21, via the bottom member 20a, the straight sub-member 20d, the slanted sub-member 20e and the upper connecting portion 22, and then back to the lower connecting portion 21, as shown in
Next, in terms of the frame structure thus constructed of the projection display apparatus, an effect of installation conditions on the apparatus will be described. For comparison, a conventional projection display apparatus is placed on an uneven floor, as will be first described. Installing the conventional projection display apparatus on the uneven floor causes the effect to transmit from the bottom members 20a of the bottom frame 20 to the cabinet. Assuming that the cabinet is a rigid body, the cabinet will slant with respect to the ground surface owing to the floor unevenness; however, because of the cabinet not being deformed, relative positions of the optical engine 2, the top mirror 3 and the screen 4 do not vary, thus causing no misregistration in an image. However, actually, a distortion arises because the cabinet is not a rigid body. Unevenness of the floor causes the bottom members 20a of the bottom frame 20 to distort, and the distortion is transmitted to the holding frame 7. The distortion transmitted to the holding frame 7, in turn, transmits to the screen frame 5; thus, the relative positions of the optical engine 2, the top mirror 3 and the screen 4 are resultingly displaced, thereby causing misregistration in an image.
On the other hand, even when the projection display apparatus according to Embodiment 1 is placed on the uneven floor, the relative positions between the optical engine 2, the top mirror 3 and the screen 4 does not vary due to the following reason. The reason will be described with reference to
Configuring a rear cover with a single part results in fastening the rear cover of the single part to the main frame assembly 11 and the bottom frame 20. For that reason, a problem is that the deformation of the bottom frame 20 is transmitted via the rear cover to the main frame assembly 11, thus resulting in the main frame assembly 11 being deformed and in varying the relative positions of the optical components.
On the other hand, as described above, if the first rear cover 41 and the second rear cover 42 are configured with different parts, then the distortion transferred to the second rear cover 42 owing to the deformation of the bottom frame 20 is not transferred to the first rear cover 41. Therefore, the main frame assembly 11 is hard to be affected by the deformation of the bottom frame 20.
Next, the top mirror 3 will be described with reference to
On the other hand, it is conceivable that only the reinforcing member ensures the planarity of the top mirror 3, while it is conceivable that reinforcement with consideration of deformation due to its own weight of the reinforcing member is needed, thus leading to significant increase of the weight. Because the configuration according to Embodiment 1 does not need to increase the stiffness of the reinforcing member when compared to the construction where the deformation is reduced by stiffness, an advantage is that a lighter weight frame can be configured.
In the projection display apparatus where light emitted from the light source unit 1 is reflected by the top mirror 3 and then projected on the screen 4, since the optical path from the light source unit 1 to the screen 4 is long, misalignment of an angle between optical components by merely 0.1 degrees causes the image on the screen 4 to come out of registration by nearly 10 mm; however, as in the projection display apparatus according to Embodiment 1, by putting all the optical components in the main frame assembly 11 and supporting the main frame assembly 11 by the bottom frame 20, misalignment of the optical components can be avoided and misregistration in an image on the screen 4 can be reduced.
As described above, since, in the projection display apparatus according to the present invention, the screen frame 5, the rear frame 6 and the holding frame 7 are integrally configured as the main frame assembly 11, accuracy in assembling the optical engine 2, the top mirror 3, and the screen 4, that are held by such frames, is easy to ensure, thus allowing higher accuracy in relative positions to be maintained.
Furthermore, since lowering the stiffness of the bottom frame 20 more than that of the main frame assembly 11 causes the distortion of the bottom frame 20 to be relatively larger than that of the main frame assembly 11, the distortion of the main frame assembly 11 can be reduced to a small value, thereby further reducing misalignment of the optical components.
Further, since the projection display apparatus according to the present invention has the optical path elongated by reflecting back by the top mirror 3 the laser beam emitted from the optical engine 2, the depth-wise dimension of the apparatus can be made small, thus enabling thinness of the apparatus to be achieved. Moreover, as shown in
Here, although the light source 101 is assumed to be configured by three laser generators emitting three laser beams, the number of laser beams emitted and the number of laser generators are not limited to this value. Further, when the image projected on the screen 4 is of mono color, the light source may be configured by using one laser generator that emits a laser beam of a particular wavelength.
Further, although each of the frames is secured by screws, it may be fixedly attached by another method such as welding or adhesive bonding.
In Embodiment 1, the projection display apparatus mounted on a rack cabinet or installed on the floor has been described; however, it can also be mounted on a wall, as will be described below with reference to
Referring to
As described above, because, in the projection display apparatus according to Embodiment 2, the main frame assembly 11 is placed via the bottom frame 20 on an installation object, deformations due to the condition of the installation object and the installation conditions occur in the bottom frame 20, which can reduce the deformations in the main frame assembly 11. Therefore, each of the relative positions of the optical engine 2, the top mirror 3 and the screen 4, can be maintained.
Although in Embodiment 1 and Embodiment 2, laser beams emitted from the light source unit is caused to directly strike on the optical engine 2, the laser beams can be caused to strike there via transfer means for transferring them. Optical fibers can be used for the transfer means. When using the optical fibers, the laser beams transferred from each of the optical fibers may strike on the optical engine 2 by providing an optical fiber for each wavelength of light to be emitted from the light source unit 1. At this instance, as with Embodiment 1, the light of each wavelength can be combined together using a dichroic prism 201. On the other hand, when the diameter of an exit end of each optical fiber is sufficiently smaller than that of an entry end of a mixing rod 202 and if the emission light from any of the optical fibers is caused to strike on the mixing rod 202, the laser beams can be combined together without using the dichroic prism 201.
In this way, when using transfer means that flexibly varies its shape like the optical fibers, the light source unit 1 does not need to be disposed on the holding frame 7; by disposing the light source unit 1 on, for instance, the bottom frame 20, the light source unit 1 can be connected to the optical engine 2 using the optical fibers. Since disposing the light source unit 1 on the bottom frame 20 can reduce the optical component count retained by the main frame assembly 11, an advantage is that the distortion due to the weight of the optical components in the main frame assembly 11 is hard to generate. Here, the light source unit 1 may be placed on the main frame assembly 11, as with Embodiment 1.
Although in Embodiment 1 through Embodiment 3 above, the lower end portion of the holding frame 7 is assumed to be screw-secured to the lower connecting portions 21 of the bottom frame 20, the lower end portions of the bottom frame 20 and the holding frame 7 do not need to be connected together; for instance, as shown in
Although in Embodiment 1, the laser beams emitted from the optical engine 2 is assumed to be reflected by the top mirror 3, another method can be used without using the top mirror 3.
Referring to
The first supporting plate 51 on which the optical engine 2 is mounted is secured to a second supporting plate 52. Further, the rear side of the projection display apparatus is covered with a rear cover 43. The second supporting plate 52 has four protrusion members 53 formed thereon. The second supporting plate 52 and a bottom frame 23 are secured together with the four protrusion members 53 passed through the four through-holes 24 drilled on the bottom frame 23. The four protrusion members 53 of the second supporting plate 52 and the four through-holes of the bottom frame 23 are provided at a location where other portions except the bottom frame 23 of the projection display apparatus hang in mid-air when the second supporting plate 52 is attached to the bottom frame 23.
The cabinet structure is configured such that the stiffness of the rear portion where the protrusion members 53 of the second supporting plate 52 are provided is higher than that of the bottom frame 23. With this configuration, even when the bottom frame 23 is distorted by the effect, etc. of the installation surface, the second supporting plate 52 is hard to distort, thus allowing the positional relationship between the nonplanar mirror 205 and the screen 4 to be maintained.
Here, the supporting plate 52 in Embodiment 4 is made up of a plate facing up to and in parallel with the surface of the screen 4, and two plates extending, toward the surface of the screen 4, outwardly diagonally from the right and left sides of the former plate; however, in lieu of the two plates fanning out from the right and left sides thereof, as shown in
Further, although the bottom frame 23 is made up of a single plate of L shape, it may be configured with a plurality of L-shaped members that are disposed with the right-left symmetry maintained. Configuration of the bottom frame 23 with the plurality of L-shaped members allows for reduction in the stiffness of the bottom frame 23.
Although in
Although in Embodiment 1 through Embodiment 4 above, the laser beam sources are used as the light source 101, a high intensity discharge lamp (HID) can be used as the light source. Since light emitted from the HID is white light, unlike the cases in the laser beam sources, the dichroic prism 201 that combines light from the light source together is not needed. Instead, however, a color wheel for converting the light from the light source 101 into the red, blue, and green colors needs to be placed between the mixing rod 202 and the DMD 203. LEDs can also be used as the light source 101. When using the LEDs, as with the cases in the laser beam sources, the light may be combined together using the dichroic prism 201, or combined together when the light is caused to strike on the mixing rod 202 after it has transmitted through the optical fibers.
Further, although, in Embodiment 1 through Embodiment 4 above, the main frame assembly 11 is assumed to be held by the bottom frame 20 and the supporting plate 52, by the bottom frame 23, the main frame assembly 11 and the supporting plate 52 may be designed to be placed directly against an installation object such as a wall. In this case, the stiffness of the main frame assembly 11 should be made higher so that the main frame assembly 11 may not distort when a force from the installation object is exerted thereon. While the present invention has been shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and the like could be made thereto without departing from the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-149814 | Jun 2009 | JP | national |
