JP6550997B2 - Image projection device - Google Patents

Description

  The present invention relates to an image projection apparatus.

  Conventionally, in an image projection apparatus such as a projector, as a technique for increasing the resolution of a projected image, an actual projected image is obtained in a short cycle other than a technique for increasing the number of images of an image display element (DMD: Digital Micro-mirror Device). There is known a method of generating an intermediate image (formed from surrounding pixels) on the screen with a half-pixel shift in the 45-degree oblique direction.

  There are two known methods for shifting the projected image by half a pixel, a method for shifting a part of the lenses in the projection lens and a method for shifting the DMD. As a method for cooling the DMD, a method is known in which a heat sink is pressed against the DMD, and cooling is performed using heat conduction.

  The method of shifting some of the lenses in the projection lens can achieve half-pixel shift movement (high resolution movement), but it is difficult to move the projected image up and down, left and right, and the projected image is rotated. The movement to make is not realizable. On the other hand, in the method of shifting the image display element (DMD), not only half pixel shift movement (high resolution movement) but also movement for moving the projected image up, down, left and right, and further movement for rotating the projected image is also one. This can be realized with a drive unit.

  However, in the case where the drive direction of the drive unit is constituted by two axes of the horizontal axis and the vertical axis on the screen, the vertical and horizontal shifts of the projected image can be realized by driving in each single axis direction. Therefore, when shifting by shifting by half a pixel in the direction of 45 degrees diagonally, it is necessary to drive at high speed with the resultant force of both axes, so the control becomes complicated.

  Therefore, an image display device that displays an image with a resolution higher than the number of pixels with a simple configuration without impairing the layout of the optical system is disclosed (for example, see Patent Document 1). In this image display device, a method is disclosed in which an intermediate image is created by displacing an optical modulation element by an actuator to shift a pixel to form a high resolution image.

  In the prior art, in the case where the heat sink is pressed against the DMD to cool the DMD as described above, when moving the projection image, not only the DMD but also the heat sink pressed against the DMD needs to be shifted simultaneously. is there. The heat sink is often a block of aluminum with high thermal conductivity, and is sufficiently heavy compared to DMD. Therefore, compared to the case where only the DMD is shifted, it is more susceptible to the influence of gravity.

  In particular, in the case where the drive plane of the DMD and the heat sink is perpendicular to the horizontal plane, a larger drive force is required because the DMD and the heat sink are shifted against gravity. However, when the drive direction of the drive unit is constituted by two axes of the horizontal axis and the vertical axis on the screen, there is a problem that the shift in the gravity direction has to be lifted only by the drive force of the vertical axis. Further, in the image display device of Patent Document 1, the relative positional relationship between the optical modulation element and the projection optical system is fixed, and therefore the projection image can not be rotated.

  The present invention has been made in view of the above, and can realize high resolution of a projected image and shift / rotation of a projected image by shifting a movable part including the DMD and a heat sink with a simple configuration, and An object of the present invention is to provide an image projection apparatus that can increase the movable weight of a movable part including a heat sink and has few layout restrictions.

In order to solve the above-described problems and achieve the object, an image projection apparatus of the present invention includes a light source that emits light, a modulation element that generates an image using light emitted from the light source, and the light source. An illumination optical unit that guides irradiated light to the modulation element, a fixed unit fixed to the illumination optical unit, a movable unit that holds the modulation element and can be moved relative to the fixed unit; A driving unit for moving the movable unit, comprising: a projection unit that projects an image generated by the modulation element; a coil disposed in the movable unit; and a magnet disposed in the fixed unit; A first driving force acting in a first direction forming an angle of more than 0 degrees and less than 90 degrees with respect to the horizontal direction, and a second direction forming an angle of more than 90 degrees and forming less than 180 degrees with respect to the horizontal direction Do Having a drive unit for generating a second drive force.

  According to the present invention, the movable part including the DMD and the heat sink can be shifted to realize high resolution of the projection image and shift / rotation of the projected image by a simple configuration, and the movable part including the DMD and the heat sink is movable The effect is that the weight can be increased and the layout restrictions can be reduced.

FIG. 1 is a perspective view of a projector according to the embodiment. FIG. 2 is a side view of the projector according to the embodiment. FIG. 3 is a view showing a state in which the exterior cover of the projector according to the embodiment is removed. FIG. 4 is a diagram showing the configuration of an optical engine inside the projector according to the embodiment. FIG. 5 is a diagram showing the configuration of the image generation unit of the projector according to the embodiment. FIG. 6 is an exploded perspective view of the fixed unit in the image generation unit. FIG. 7 is an exploded perspective view of the movable unit in the image generation unit. FIG. 8 is a diagram showing the positional relationship between the fixed unit and each plate in the movable unit. FIG. 9 is an explanatory diagram of the drive direction of the DMD in the projector of the first embodiment. FIG. 10 is an explanatory diagram of the drive direction of the DMD in the projector of the first embodiment. FIG. 11 is an explanatory diagram of the drive direction of the DMD in the projector of the first embodiment.

  Hereinafter, embodiments of an image projection apparatus will be described in detail with reference to the accompanying drawings. Below, the example which applied the image projection apparatus to the projector is shown.

  FIG. 1 is a perspective view of a projector according to the embodiment. FIG. 2 is a side view of the projector according to the embodiment. The projector 1 is a device that generates a video based on video data input from a PC (Personal Computer), a video camera, or the like, and projects the generated video on a screen 2 that is a projection object for display. FIG. 2 shows a state in which the projection light emitted from the projection lens 15 of the projector 1 is irradiated on the screen 2.

  In the liquid crystal projector widely known as a projector, recently, the resolution of the liquid crystal panel has been increased, the brightness has been improved with the increase in efficiency of the light source lamp, and the price has been reduced. In addition, with the spread of small and light projectors using DMD as an image display element, they are widely used not only in offices and schools but also at home. In particular, front-type projectors have improved portability and are being used for small meetings of several people.

  The projector 1 is required to project a large screen image (increasing the projection screen) and to make the “projection space required outside the projector” as small as possible. In recent years, the performance of the optical engine 3 (see FIG. 3) has been improved, and the projector 1 that can achieve a projection size of 60 inches to 80 inches with a projection distance of 1 to 2 m has become mainstream.

  In the case of a projector having a long projection distance, there is a conference desk between the projector and the screen, and the projector is arranged behind the conference desk. However, in recent years, with a reduction in projection distance, it has become possible to place a projector on the front side of a conference desk, and the space behind the projector can be freely utilized.

  Further, since the projector houses a light source lamp and a large number of electronic boards, the internal temperature rises with the passage of time after startup. This is remarkable in recent years in which miniaturization of the casing size of the projector is progressing. Therefore, as a countermeasure, as shown in FIG. 1, an air inlet 11 and an air outlet 12 are provided and an air cooling method using forced air flow is used so as not to exceed the heat resistance temperature of the components inside the projector.

  FIG. 3 is a view showing a state in which the exterior cover of the projector according to the embodiment is removed. The projector 1 is provided with an optical engine 3 and a light source unit 4, and FIG. 3A shows a state in which they are arranged. Further, FIG. 3B shows a state in which the optical engine 3 and the light source unit 4 are taken out of the projector 1. The light source unit 4 emits light, and in the present embodiment, a high pressure mercury lamp is adopted.

  A path until the light emitted from the light source unit 4 forms an image on the screen 2 will be described. First, the light emitted from the light source unit 4 is emitted to the illumination unit 3 a of the optical engine 3. In the illumination unit 3a, the white light irradiated by the optical element is split into RGB, and the split light is guided to the DMD 10 (see FIG. 4). The light guided to the DMD 10 is formed into an image according to the modulation signal, and reaches the screen 2 to be enlarged and projected by the projection unit 3b. The illumination unit 3a corresponds to an illumination optical unit.

  Further, the air cooling system inside the projector 1 shown in FIG. 1 is implemented by forced air flow by the intake fan 13 disposed in the vicinity of the intake port 11 and the exhaust fan 14 disposed in the vicinity of the exhaust port 12 .

  FIG. 4 is a diagram showing an internal configuration of the projector according to the embodiment. FIG. 4 shows a cross-sectional view of the illumination unit 3 a and the projection unit 3 b of the optical engine 3 and the light source unit 4 in the projector 1.

  In the optical engine 3, first, white light emitted from the light source unit 4 is converted into RGB colors by a disk-shaped color wheel 5. Then, the light emitted from the color wheel 5 is guided into the illumination unit 3a by the light tunnel 6 that is formed in a cylindrical shape by laminating plate glasses. Then, the chromatic aberration is corrected by the two relay lenses 7 disposed immediately after the light tunnel 6, and the flat mirror 8 and the concave mirror 9 condense the light on the image generation unit 20 having the DMD 10.

  The DMD 10 generates an image using light emitted from the light source unit 4. Specifically, the DMD 10 has a substantially rectangular mirror surface composed of a plurality of micromirrors, and processes the projection light into a predetermined video by driving each micromirror in a time-sharing manner based on video data. And has a structure that reflects light. The DMD 10 reflects light in two directions. The light used for generating the video data is reflected to the projection lens 15 and the light discarded without being used is reflected to the OFF light plate.

  The light used for generating the image data is reflected to the side of the projection unit 3b, expanded as it passes through the plurality of projection lenses 15, and projected onto the screen 2 as enlarged image light. The projection unit 3 b corresponds to a projection unit, and projects the image generated by the image generation unit 20 on the screen 2. The incident side of the relay lens 7, the flat mirror 8, the concave mirror 9, the DMD 10, and the projection unit 3b inside the illumination unit 3a is held by the housing so as to cover each component, and the mating surface of the housing is the seal material It has a sealed dustproof structure.

  Next, the image generation unit 20 will be described. FIG. 5 is a diagram showing the configuration of the image generation unit of the projector according to the embodiment. As shown in FIG. 5, the image generation unit 20 is mainly composed of two units, a fixed unit 31 and a movable unit 41. FIG. 6 is an exploded perspective view of the fixed unit in the image generation unit. FIG. 7 is an exploded perspective view of the movable unit in the image generation unit.

  As shown in FIG. 6, the fixing unit 31 includes a top plate 32 and a base plate 33. Further, as shown in FIG. 7, the movable unit 41 includes a movable plate 42 and a coupling plate 46. FIG. 8 is a diagram showing the positional relationship between the fixed unit and each plate in the movable unit. Below, with reference to FIGS. 5-8, the detail of the fixed unit 31 and the movable unit 41 is demonstrated.

  The movable unit 41 is configured to be movable relative to the fixed unit 31 by receiving a reaction force when a force is applied to the fixed unit 31 using a driving force of an actuator as a driving unit. It has become. That is, the movable unit 41 is configured to be movable relative to the lighting unit 3a to which the fixed unit 31 is fixed.

  Further, in order to reduce the resistance that the movable unit 41 receives from the fixed unit 31, a plurality of spheres 34 are provided between the fixed unit 31 and the movable unit 41 as shown in FIG. 6. The spheres 34 reduce the sliding friction between the two units. The position of the sphere 34 is shown in FIG.

  First, the fixed unit 31 will be described. The fixed unit 31 shown in FIG. 6 has two roles of supporting the movable unit 41 (see FIG. 7) and supporting the movement of the movable unit 41.

  Specifically, first, the fixed unit 31 supports the movable unit 41 by sandwiching the movable plate 42 in the movable unit 41 with a plurality of spheres 34 provided in the fixed unit 31.

  The spheres 34 are disposed between the top plate 32 and the movable plate 42 and between the base plate 33 and the movable plate 42, respectively. The sphere 34 disposed on the top plate 32 side is accommodated in the sphere holding portion 35 provided on the top plate 32, and the sphere 34 disposed on the base plate 33 side is accommodated in the sphere receiving portion 36 disposed on the base plate 33 side. It is the composition which becomes.

  Here, although the relationship between friction and rattling changes depending on the clearance between each plate and the ball 34, the clearance can be adjusted by the ball position adjusting screw 39 provided on the top plate 32 side. Further, between the top plate 32 and the base plate 33, a support 38 for keeping the distance between both plates is provided.

  Next, support for movement of the movable unit 41 by the fixed unit 31 will be described. A magnet 37 is disposed on the fixed unit 31 side of the projector 1, and a voice coil 43 is disposed on the movable unit 41 side. The magnet 37 and the voice coil 43 are actuators and correspond to a drive unit.

  In the projector 1 according to the present embodiment, a Lorentz force is generated by passing a current through the voice coil 43, and the movable unit 41 moves. That is, the magnet 37 and the voice coil 43 are actuators using an electromagnetic force and correspond to a drive unit. Here, the direction of the Lorentz force changes depending on the direction of the current flowing through the voice coil 43, and the magnitude of the Lorentz force changes depending on the magnitude of the current. Therefore, by adjusting the direction and magnitude of the current flowing through the voice coil 43, the movable unit 41 having the DMD 10 can be moved in a desired direction by a desired amount.

  Next, the movable unit 41 will be described. The movable unit 41 has a role of holding the DMD 10. The DMD 10 generally has a configuration in which it is held between the illumination housing and the heat sink. However, in the projector 1 of the present embodiment, as shown in FIG. 7, the DMD 10 is covered by the DMD holding bracket 47 which is one of the components of the movable unit 41. Thus, the DMD 10 can be held without being pressed against the illumination housing.

  As shown in FIG. 7, the movable unit 41 is roughly composed of two units, a movable plate unit 44 and a DMD holding unit 45. The movable plate unit 44 is mainly composed of a movable plate 42 and a voice coil 43, and is a unit that moves relative to the force from the fixed unit 31.

  On the other hand, the DMD holding unit 45 mainly includes the DMD 10, the heat sink 18, the coupling plate 46, and the DMD holding bracket 47, and is a unit for holding the DMD 10. When the coupling plate 46 is coupled to the movable plate 42, the movement amount of the movable plate unit 44 is transmitted to the DMD holding unit 45, thereby realizing the movement of the DMD 10.

  The heat sink 18 diffuses and radiates heat generated by light emitted from the light source unit 4 and corresponds to a heat radiating unit. The heat sink 18 is pressed against the DMD 10 to cool the DMD 10 using heat conduction. Further, since the heat sink 18 is pressed by the DMD 10, the heat sink 18 moves integrally with the DMD 10 when the DMD 10 moves.

  Since the movable plate 42 is supported by being sandwiched between the spheres 34 in the fixed unit 31 as described above, the movable plate 42 itself is connected to the top plate 32 of the fixed unit 31 as shown in FIG. It will be disposed between the base plates 33. Further, the DND holding bracket 47, the coupling plate 46, and the heat sink 18 are fixed from the heat sink 18 side by a shoulder screw 48 provided with a spring 49.

  That is, as shown in FIG. 8, in the image generation unit 20, the top plate 32 and the base plate 33 that form the fixed unit 31, and the movable plate 42 and the coupling plate 46 that form the movable unit 41 are alternately arranged. With this arrangement, Lorentz force is applied to the movable plate 42, and the drive by the Lorentz force is transmitted to the DMD holding unit 45. That is, the drive by Lorentz force is transmitted to the DMD 10 to shift the DMD 10.

  Next, driving of the DMD 10 by the actuator will be described. 9 to 11 are explanatory diagrams of the drive direction of the DMD by the drive unit in the projector according to the first embodiment.

  In FIG. 9, when the horizontal direction is the x-axis direction and the gravity (vertical) direction is the y-axis direction, the first X-axis direction that forms an angle R1 of greater than 0 degrees and less than 90 degrees with respect to the horizontal direction, There is a coordinate axis according to the Y-axis direction of the second direction forming an angle R2 of more than 90 degrees and less than 180 degrees with respect to the direction. The actuator moves the DMD 10 by a first driving force acting in the X-axis direction and a second driving force acting in the Y direction.

  In this embodiment, when the horizontal direction is the x-axis direction and the gravity (vertical) direction is the y-axis direction, the direction (first direction) that forms 45 degrees (angle R1) with respect to the horizontal direction is the X-axis direction. The direction rotated 90 degrees with respect to the X-axis direction, that is, the direction (second direction) forming 135 degrees (angle R2) with respect to the horizontal direction is defined as the Y-axis direction.

  In the projector 1 according to the present embodiment, as shown in FIG. 9, two sets of voice coils 43a are arranged at an angle of 45 degrees with respect to the horizontal direction, that is, along the X-axis direction and the Y-axis direction. Thereby, as indicated by an arrow A, a driving force (second driving force) that is a Lorentz force acting in the Y-axis direction is generated. This driving force enables the DMD 10 to move in the direction of the arrow F1, and realizes a motion of shifting the projection image by half a pixel in the 45-degree oblique direction, which is a motion of high resolution. As described above, by realizing the movement of the projection image by the half pixel shift in the 45-degree oblique direction only by the Y axis which is a single axis, it is possible to control the projection image with a simple configuration and achieve high resolution. In addition, shift and rotation of the projected image can be realized by further adding driving forces in different directions.

  Specifically, in the projector 1 of the present embodiment, as shown in FIG. 10, two sets of voice coils 43b are arranged in a direction perpendicular to the voice coil 43a. Thereby, as indicated by an arrow B, a driving force (first driving force) that is a Lorentz force acting in the X-axis direction is generated. As described above, the combined force of the driving force by the voice coil 43a and the driving force by the voice coil 43b can move the DMD 10 in the horizontal direction (x-axis direction) or the gravity direction (y-axis direction). Then, by translating the DMD 10 vertically and horizontally, it is possible to realize the shift of the projection image.

  Further, in the projector according to the present embodiment, Lorentz acts in the opposite direction in the X-axis direction as shown by arrows B and C in FIG. 11 by supplying currents in opposite directions to the two sets of voice coils 43b. A driving force that is a force is generated. Thus, the DMD 10 can be rotated in the arrow F2 direction by the driving force in the opposite direction. By rotating the DMD 10, rotation of the projected image can be realized.

  Further, as shown in FIG. 10, in order to shift the projected image in the gravity direction (y-axis direction), that is, to move the DMD 10 by the combined force of the driving force in the X-axis direction and the Y-axis direction, The movable weight of the movable portion (movable unit 41) can be increased. Accordingly, since a necessary driving force can be obtained without increasing the number of actuators, restrictions on the layout of other components can be reduced.

  As described above, in the projector 1 according to the embodiment, the driving force acting in the direction of 45 degrees with respect to the horizontal direction and the driving force acting in the direction of 135 degrees with respect to the horizontal direction The DMDs 10 generated in pairs and provided in the movable unit 41 are moved. Therefore, the movable unit 41 (movable portion) including the DMD 10 and the heat sink 18 can be shifted by a simple configuration to realize high resolution of the projected image and shift / rotation of the projected image. The movable weight can be increased, and layout constraints can be reduced.

Reference Signs List 1 projector 2 screen 3 optical engine 3a lighting unit 3b projection unit 4 light source unit 5 color wheel 6 light tunnel 7 relay lens 8 plane mirror 9 concave mirror 10 DMD
11 air intake 12 exhaust 13 air intake fan 14 air exhaust fan 15 projection lens 18 heat sink 20 image generation unit 31 fixed unit 32 top plate 33 base plate 34 sphere 35 sphere holding portion 36 sphere receiving portion 37 magnet 38 post 39 sphere position adjusting screw 41 movable Unit 42 Movable plate 43 (43a, 43b) Voice coil 44 Movable plate unit 45 DMD holding unit 46 Coupling plate 47 DMD holding bracket 48 Step screw 49 Spring

JP 2007-248721 A

Claims (11)

A light source for emitting light,
A modulation element that generates an image using light emitted from the light source;
An illumination optical unit for guiding the light emitted from the light source to the modulation element;
A fixed unit fixed to the illumination optical unit;
A movable unit that holds the modulation element and is movable relative to the fixed unit;
A projection unit for projecting an image generated by the modulation element;
An angle of more than 0 degrees and less than 90 degrees with respect to the horizontal direction, which is a driving force for moving the movable unit, includes a coil disposed on the movable unit and a magnet disposed on the fixed unit. A driving unit generating a first driving force acting in a first direction and a second driving force acting in a second direction forming an angle of more than 90 degrees and less than 180 degrees with respect to the horizontal direction ;
An image projection apparatus having The first direction is a direction that forms an angle of 45 degrees with respect to the horizontal direction,
The image projection apparatus according to claim 1, wherein the second direction is a direction that forms an angle of 135 degrees with respect to the horizontal direction.   The image projecting device according to claim 1, wherein the driving unit moves the modulation element in the horizontal direction or the gravity direction by a resultant force of the generated first driving force and the second driving force.   The image projection apparatus according to claim 3, wherein the drive unit is an actuator using an electromagnetic force. The image projection apparatus according to claim 4, wherein a plurality of the driving units are disposed, and rotate the modulation element by passing a current in the opposite direction.   The heat generating part which diffuses the heat produced | generated with the light irradiated from the said light source, and moves integrally with the said modulation element by being pressed by the said modulation element, It further has any 1 part of Claim 1-5. The image projection apparatus described in one.   The movable unit includes a heat dissipation unit
  The image projection apparatus according to any one of claims 1 to 6, wherein   The fixing unit comprises a top plate and a base plate,
  The movable unit is
  A movable plate provided with the coil;
  And a coupling plate that couples the modulation element, the heat dissipation unit, and the movable plate.
  The image projection apparatus according to claim 7, characterized in that   The top plate and the base plate, and the movable plate and the coupling plate are alternately arranged.
  The image projection apparatus according to claim 8, characterized in that:   The magnet is provided between the top plate and the base plate
  The image projection apparatus according to claim 8 or 9, characterized in that A plurality of spheres are provided between the fixed unit and the movable unit.
The image projection apparatus according to claim 1, wherein: