JP2017102174A - Image projection device, optical engine, and image display unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image projection device for achieving the shift and rotation of a projection image and for achieving miniaturization and cost reduction by reducing the number of fastening components between components.SOLUTION: The image projection device includes a DMD (digital micro-mirror device) 16 which generates an image by using light radiated from a light source, an illumination unit which is for guiding the light radiated from the light source to the DMD 16, a projection unit which projects the image generated by the DMD 16, an actuator (a magnet and a voice coil 43) which moves a movable unit 41 holding the DMD 16, so as to relatively move the DMD 16 with respect to the illumination unit, and a heat sink 18 which is provided in the movable unit 41 and diffuses the heat of the DMD 16. The voice coil 43 which is a part of the actuator is arranged in the heat sink 18.SELECTED DRAWING: Figure 8

Description

  The present invention relates to an image projection apparatus, an optical engine, and an image display unit.

  Conventionally, in an image projection apparatus such as a projector, as a method for increasing the resolution of a projection image, a method for increasing the number of images of an image display element (DMD: Digital Micro-mirror Device) is used. A method of shifting by half a pixel in an oblique 45 degree direction is known.

  As a method of shifting the projected image by half a pixel, a method of directly shifting DMD is known. This method has an advantage that the projected image can be moved up and down, left and right (shifted), and the projected image can be rotated, in addition to the half-pixel shifting (higher resolution). Further, as a method for cooling the DMD, a method is known in which a heat sink is pressed against the DMD and is cooled using heat conduction.

  For example, Patent Document 1 discloses an image display device that displays an image with a resolution higher than the number of pixels without increasing the number of pixels of the optical modulation element. In this image display device, a method is disclosed in which an intermediate image is created by shifting pixels by moving an optical modulation element by an actuator to form a high-resolution image.

  However, in the image display device of Patent Document 1, it is impossible to rotate the projection image, and it is necessary to increase the prism thickness when performing a large optical path change that greatly shifts the projection image. The entire device becomes large. Further, in the case of the structure in which the DMD is cooled by pressing the heat sink described above, it is necessary to shift not only the DMD but also the heat sink at the same time in order to move the projection image. For this reason, the drive mechanism requires a component that directly acts on the drive force and a component that fastens the component, the DMD, and the heat sink, resulting in an increase in the size of the entire apparatus.

  The present invention has been made in view of the above, and can achieve high resolution of the projected image and shift / rotation of the projected image, and can reduce the size and cost of the components by fastening the components to each other. It is an object of the present invention to provide an image projection device, an optical engine, and an image display unit that can be converted into a single image.

  In order to solve the above-described problems and achieve the object, the present invention provides an image projection apparatus, a light modulation element that generates an image using light emitted from a light source, and light emitted from the light source. By moving an illumination optical unit for guiding the light modulation element to the light modulation element, a projection unit that projects an image generated by the light modulation element, and a movable unit that holds the light modulation element. A drive unit that relatively moves the light modulation element, and a heat dissipation unit that is provided in the movable unit and diffuses heat of the light modulation element, wherein the heat dissipation part is a part of the drive unit including.

  According to the present invention, it is possible to achieve high resolution of a projected image and shift / rotation of a projected image, and to reduce the number of parts that fasten the parts and reduce the size and cost.

FIG. 1 is an external view of an image projection apparatus according to an embodiment. FIG. 2 is a diagram showing the arrangement and configuration of the optical engine and the light source unit. FIG. 3 is a diagram illustrating a configuration example of the optical engine. FIG. 4 is a diagram illustrating a configuration example of the image display element unit. FIG. 5 is a diagram for explaining the Lorentz force generated between the voice coil and the magnet. FIG. 6 is a diagram for explaining the Lorentz force generated between the voice coil and the magnet. FIG. 7 is an exploded perspective view of the fixed unit. FIG. 8 is an exploded perspective view of the movable unit. FIG. 9 is a diagram showing the positional relationship between the plates.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1A is a perspective view of the image projection apparatus 1 according to this embodiment, and FIG. 1B is a side view of the image projection apparatus 1. 1B shows a state in which the projection light emitted from the image projection apparatus 1 is applied to the screen (projected object) 2 on which the image is projected.

  The image projection apparatus 1 is an apparatus that generates an image based on image data input from a personal computer, a video camera, or the like, and projects and displays the image on a screen 2 or the like. A liquid crystal projector widely known as the image projection apparatus 1 has recently been improved in the resolution, the price, and the like with an increase in the resolution of the liquid crystal panel and the efficiency of the light source lamp. In addition, small and light projectors using DMD (Digital Micro-mirror Device) have become widespread, and these projectors are widely used not only in offices and schools but also at home. In particular, front-type projectors have improved portability and have been used for small meetings of several people.

  The projector that is the image projection apparatus 1 is required to be able 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 optical engines has improved, and projectors that can achieve projection sizes of 60 to 80 inches with a projection distance of 1 to 2 m have become mainstream. In the case of a projector having a long projection distance, there is a conference desk between the projector and the screen 2, and the projector is arranged behind the conference desk. It has become possible to place it on the front side of a desk, and the space behind the projector can be used freely.

  Since the projector contains a light source lamp and a large number of electronic boards, the internal temperature of the projector rises as time passes after startup. This is conspicuous in recent years when the projector housing size has been reduced, and as a countermeasure, as shown in FIG. An air cooling method using a forced air flow is generally adopted by providing an exhaust port 12.

  FIG. 2 is a view showing the arrangement and configuration of the optical engine 3 and the light source unit 4 with the exterior cover of the image projection apparatus 1 removed. In the present embodiment, a high pressure mercury lamp is employed as the light source unit 4. As a path for the light emitted from the light source unit 4 to form an image on the screen 2, the light from the light source unit 4 is first applied to an illumination unit 3 a described later of the optical engine 3. In the illumination unit 3a, the emitted white light is split into RGB, and the split light is guided to an image display element unit 8 described later. Thereafter, the light guided to the image display element unit 8 forms an image according to the modulation signal, and is enlarged and projected by a projection unit 3b described later to reach the screen 2. In addition, the air cooling method inside the image projection apparatus 1 shown in FIG. 1A is performed by forced air flow by the intake fan 13 disposed near the intake port 11 and the exhaust fan 14 disposed near the exhaust port 12. ing.

  FIG. 3 is a diagram illustrating a configuration example of the optical engine 3. As shown in FIG. 3, the optical engine 3 according to the present embodiment mainly includes an illumination unit 3a and a projection unit 3b. The illumination unit 3 a is an example of an illumination optical unit, and guides the light emitted from the light source unit 4 to the DMD 16 provided in the image display element unit 8. The projection unit 3b is an example of a projection unit, and enlarges and projects an image generated by the DMD 16 (image display element unit 8) onto the screen 2.

  In the optical engine 3 of the present embodiment, the white light emitted from the light source unit 4 is first converted into RGB colors by the disk-shaped color wheel 5. After that, light emitted from the color wheel 5 is guided into the illumination unit 3a by the light tunnel 6 configured in a cylindrical shape by laminating plate glasses, and chromatic aberration is generated by the two relay lenses 7 arranged immediately after the light tunnel 6. And the light is condensed on the image display element unit 8 having the DMD 16 by the plane mirror 10 and the concave mirror 9.

  The DMD 16 has a substantially rectangular mirror surface composed of a plurality of micromirrors, and each micromirror is driven in a time-sharing manner based on video data, thereby processing and reflecting the projection light into a predetermined video. It has a structure. Here, it can be considered that the DMD 16 which is an example of the light modulation element generates an image using light emitted from the light source unit 4. The image projection apparatus 1 according to the present embodiment is a projector in which the DMD 16 faces the screen 2.

  There are two types of directions in which the DMD 16 reflects, and light used when forming video data is reflected to the projection lens, and light that is discarded without being used is reflected to the OFF light plate. The light used in forming the video data is reflected toward the projection unit 3b, enlarged when passing through a plurality of projection lenses, and projected onto the screen 2 as enlarged video light. The incident side of the relay lens 7, the concave mirror 9, the flat mirror 10, the image display element unit 8, and the projection unit 3b inside the illumination unit 3a is held by the housing so as to cover each component, and the housing The mating surfaces have a dustproof structure sealed with a sealing material.

  The image projection apparatus 1 of the present embodiment includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like. The CPU controls the operation of the image projection apparatus 1 by developing and executing a program stored in the ROM or the like on the RAM.

  Next, a specific configuration of the image display element unit 8 will be described. FIG. 4 is a diagram illustrating an example of the configuration of the image display element unit 8. As shown in FIG. 4, the image display element unit 8 is an example of an image display unit, and includes two units, a fixed unit 31 and a movable unit 41.

  On the movable unit 41 side, a later-described voice coil 43 (an example of a coil) is disposed, and by receiving a Lorentz force generated between a later-described magnet 37 (magnet) disposed on the fixed unit 31 side, The structure moves relative to the fixed unit 31. At this time, in order to reduce the resistance that the movable unit 41 receives from the fixed unit 31, a sphere 34 is provided between the fixed unit 31 and the movable unit 41 to reduce sliding friction between the two units. . The position of the sphere 34 will be described later.

  The combination of the voice coil 43 and the magnet 37 generates a driving force for moving the DMD 16 relative to the illumination unit 3a, and may be referred to as an “actuator” in the following description. As will be described later, the image projection apparatus 1 according to the present embodiment has four actuators, and each of the four voice coils 43 is provided at a position facing the magnet 37 paired with the voice coil 43. Yes. The four actuators function as a drive unit that moves the DMD 16 relative to the illumination unit 3 a by moving the movable unit 41 that holds the DMD 16.

  For example, when the relationship between the direction of the magnetic field by the magnet 37 and the current flowing through the voice coil 43 is as shown in FIG. 5, Lorentz force acts in the direction of the arrow shown in FIG. If the direction of the current flowing through the voice coil 43 is reversed, Lorentz force acts in the direction opposite to that in FIG. 5, as shown in FIG.

  FIG. 7 is an exploded perspective view of the fixed unit 31. FIG. 8 is an exploded perspective view of the movable unit 41. As the role of the fixed unit 31, it can be said that two points of supporting the movable unit 41 and supporting the movement of the movable unit 41 are the major roles. Specifically, the movable unit 41 is supported by sandwiching the movable plate 18 a in the movable unit 41 with a plurality of spheres 34 provided in the fixed unit 31.

  The sphere 34 is disposed between the top plate 32 and the heat sink 18 and between the base plate 33 and the heat sink 18. The sphere 34 arranged on the top plate 32 side is in a sphere holding part 35 provided on the top plate 32, and the sphere 34 arranged on the base plate 33 side is on a sphere receiving part 36 provided on the base plate 33 side. It is configured to be stored. Although it can be said that the relationship between friction and backlash varies depending on the clearance between each plate and the sphere 34, the clearance is adjusted by a sphere position adjusting screw 39 provided on the top plate 32 side. Further, a support column 38 is provided between the top plate 32 and the base plate 33 to keep the distance between the plates.

  As for the support of movement of the movable unit 41, which is another role of the fixed unit 31, a magnet 37a is disposed on the fixed unit 31 side, and a voice coil 43 is disposed on the movable unit 41 side. A control circuit (which may be the above-described CPU or a circuit different from the CPU) performs a control to flow a current through the voice coil 43, thereby generating a Lorentz force and moving the movable unit 41. . That is, the actuator is a magnet 37 and a voice coil 43 that is provided facing the magnet 37 and through which a current flows. As described above, the direction of the Lorentz force varies depending on the direction of current flow, and the magnitude of the Lorentz force varies depending on the magnitude of the current. Therefore, the movable unit 41 having the DMD 16 is moved in a desired direction by a desired amount. be able to.

  A hall element 42 is attached to the heat sink 18 on the movable unit 41 side, and the position of the movable unit 41 is detected by a change in the magnetic field received from the magnet 37b on the fixed unit 31 side.

  On the other hand, the role of the movable unit 41 includes holding the DMD 16. In general, the DMD 16 is sandwiched between the illumination housing and the heat sink 18. However, as shown in the exploded perspective view of FIG. 8, in this configuration, the DMD holding bracket 47 which is one of the components of the movable unit 41. In this way, the DMD 16 is held without being pressed against the illumination housing.

  Here, the heat sink 18 is an example of a heat radiating section, and presses the DMD 16 to diffuse the heat of the DMD 16 and cool it. Specifically, the heat sink 18 is mainly composed of a cooling part 18b and a movable plate 18a provided with the cooling part 18b. The voice coil 43 described above is provided on the movable plate 18 a of the heat sink 18. That is, the heat sink 18 includes a voice coil 43 that is a part of an actuator that is a drive unit. The movable plate 18a is moved by the driving force (Lorentz force) by the actuator, so that the driving force directly acts on the heat sink 18. The movable plate 18a is an example of a movable plate.

  Further, as described above, the heat sink 18 in which the Lorentz force works is supported by being sandwiched between the spheres 34 in the fixed unit 31, so that the heat sink 18 itself is disposed between the top plate 32 and the base plate 33 of the fixed unit 31. Will be. Further, the DND holding bracket 47, the coupling plate 46 for holding the DMD 16, and the heat sink 18 are fixed from the heat sink 18 side by a stepped screw 48 provided with a spring 49. FIG. 9 is a diagram showing the positional relationship between the plates.

  As shown in FIG. 9, in this embodiment, a magnet 37 a is arranged in the fixed unit 31. On the other hand, a voice coil 43 is disposed at a position of the movable plate 18a of the heat sink 18 in the movable unit 41 facing the magnet 37a. When a driving force (Lorentz force) is generated by the actuator composed of the magnet 37a and the voice coil 43, the Lorentz force is directly applied to the heat sink 18 including a part of the actuator to drive it. Thereby, DMD16 currently pressed by the heat sink 18 currently driven can be driven indirectly.

  As described above, the image projecting apparatus 1 according to the present embodiment includes a part of the driving mechanism in the heat sink 18 that presses the DMD 16 to cool the DMD 16, thereby fastening the DMD 16 and the heat sink 18 with a component that directly acts on the driving force. Parts (fastening parts) can be minimized. Therefore, the image projection apparatus 1 according to the present embodiment can increase the resolution of the projection image and can shift and rotate the projection image, and can reduce the size and the cost by reducing the number of components that are fastened to each other. Can do.

  As mentioned above, although embodiment of this invention was described, the above-mentioned embodiment is shown as an example and is not intending limiting the range of invention. The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, some components may be deleted from all the components shown in the embodiment.

DESCRIPTION OF SYMBOLS 1 Image projector 2 Screen 3 Optical engine 3a Illumination unit (illumination optical part)
3b Projection unit (projection unit)
4 Light source unit 5 Color wheel 6 Light tunnel 7 Relay lens 8 Image display element unit 9 Concave mirror 10 Plane mirror 16 DMD (light modulation element)
18 Heat sink 18a Movable plate 18b Cooling unit 31 Fixed unit 37 (37a, 37b) Magnet (magnet)
41 Movable unit 43 Voice coil (coil)
46 Binding plate

JP 2007-248721 A

Claims (5)

An image projection device,
A light modulation element that generates an image using light emitted from a light source;
An illumination optical unit for guiding the light emitted from the light source to the light modulation element;
A projection unit for projecting an image generated by the light modulation element;
A drive unit that moves the light modulation element relative to the illumination optical unit by moving a movable unit that holds the light modulation element;
A heat dissipating part that is provided in the movable unit and diffuses heat of the light modulation element,
The heat radiation unit is an image projection device including a part of the drive unit. The drive unit is a coil that is provided facing the magnet and through which a current flows,
The image projection device according to claim 1, wherein the heat radiating unit includes the coil.   The image projection apparatus according to claim 2, wherein the heat radiating unit includes a movable plate that moves by a driving force of the driving unit, and a coil is provided on the movable plate. An optical engine,
A light modulation element that generates an image using light emitted from a light source;
An illumination optical unit for guiding the light emitted from the light source to the light modulation element;
A projection unit for projecting an image generated by the light modulation element;
A drive unit that moves the light modulation element relative to the illumination optical unit by moving a movable unit that holds the light modulation element;
A heat dissipating part that is provided in the movable unit and diffuses heat of the light modulation element,
The heat dissipation part is an optical engine including a part of the drive part. An image display unit,
A light modulation element that generates a projected image using light emitted from a light source;
A drive unit that moves the light modulation element relative to an apparatus including the image display unit by moving a movable unit that holds the light modulation element;
A heat dissipating part that is provided in the movable unit and diffuses heat of the light modulation element,
The heat dissipation unit is an image display unit including a part of the driving unit.

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