Patent Application
20090027625
This application claims priority of Taiwanese Application No. 096127528, filed on Jul. 27, 2007.
1. Field of the Invention
The invention relates to an image projection apparatus, more particularly to an image projection apparatus that utilizes a laser array as a light source thereof.
2. Description of the Related Art
As compared with a conventional light source that is utilized in an image projection apparatus such as a halogen lamp or an ultra high pressure mercury lamp, a laser emits light beams with higher color purity, thereby enabling image projection devices using laser light sources to present better color reproduction. As shown in
However, since the light beams emitted by laser diodes are inherently highly collimated, even after the light beams have been reflected multiple times in the integration rod 13, it is still difficult for the light beams outputted from the integration rod 13 to have a uniform intensity distribution. One of the ways to overcome this problem is to increase the length of the integration rod 13 so as to increase the number of times the light beams are reflected therein. However, as the integration rod 13 increases in length, the overall size of the conventional image projection apparatus increases accordingly.
In addition, since the light beams emitted by laser diodes are inherently highly coherent, speckles are formed on surfaces upon which the light beams are incident, thereby adversely affecting the image quality of the image light beam produced by the light valve 15.
Therefore, an embodiment of the present invention is to provide an image projection apparatus with better image quality, and a light source module to be incorporated in an image projection apparatus and capable of improving the image quality of the image projection apparatus.
In order to achieve one or some or all of the above-mentioned objects or other objects, according to one aspect of the present invention, an image projection apparatus is provided and includes at least one laser array, at least one reflecting unit, a diffusing member, a light uniformizing unit, a lens unit, a light valve, and a projection lens. The laser array includes a plurality of laser units that are arranged in a matrix. Each of the laser units emits a laser beam. The reflecting unit has a plurality of reflecting surfaces that are non-parallel to each other, and that are disposed to receive and reflect the laser beams emitted by the laser units. The diffusing member is disposed to receive and diffuse the laser beams reflected from the reflecting surfaces of the at least one reflecting unit so as to form an illumination beam. The light uniformizing unit is disposed to receive and uniformize the illumination beam from the diffusing member. The lens unit is disposed to receive the illumination beam from the light uniformizing unit for adjusting a cross-sectional area of the illumination beam. The light valve is disposed to receive and modulate the adjusted illumination beam from the lens unit so as to form an image light beam. The projection lens is disposed to project the image light beam from the light valve onto a screen so as to form an image.
According to another aspect of the present invention, a light source module is provided. The light source module is adapted for use in an image projection apparatus, and includes at least one laser array, at least one reflecting unit, a diffusing member, and a light uniformizing unit. The laser array includes a plurality of laser units that are arranged in a matrix. Each of the laser units emits a laser beam. The reflecting unit has a plurality of reflecting surfaces that are non-parallel to each other, and that are disposed to receive and reflect the laser beams emitted by the laser units. The diffusing member is disposed to receive and diffuse the laser beams reflected from the reflecting surfaces of the at least one reflecting unit so as to form an illumination beam. The light uniformizing unit is disposed to receive and uniformize the illumination beam from the diffusing member.
By diffusing the laser beams reflected by the reflecting surfaces so as to form the illumination beam prior to entering the light uniformizing unit, it is ensured that the illumination beam exiting from the light uniformizing unit has a uniform intensity distribution. This not only enhances the image quality of the image light beam produced by the light valve, the need to increase the length of the light uniformizing unit is also eliminated.
In addition, by further including an actuating unit that is operable to drive movement of the reflecting unit relative to the diffusing member for causing reciprocating movement of the laser beams that are reflected by the reflecting surfaces of the reflecting unit and that are incident upon the diffusing member at a predetermined frequency, coherence inherent in the laser beams is destroyed, thereby preventing the formation of speckles on the light valve that adversely affect the image quality of the image light beam produced by the light valve.
Other objectives, features and advantages of the present invention will be further understood from the further technological features disclosed by the embodiments of the present invention wherein there are shown and described preferred embodiments of this invention, simply by way of illustration of modes best suited to carry out the invention.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiments with reference to the accompanying drawings, of which:
In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which there are shown by way of illustration specific embodiments in which the invention may be practiced. In this regard, directional terminology, such as “top,” “bottom,” “front,” “back,” etc., is used with reference to the orientation of the Figure(s) being described. The components of the present invention can be positioned in a number of different orientations. As such, the directional terminology is used for purposes of illustration and is in no way limiting. On the other hand, the drawings are only schematic and the sizes of components may be exaggerated for clarity. It is to be understood that other embodiments may be utilized and structural changes may be made without departing from the scope of the present invention. Also, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including,” “comprising,” or “having” and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings. Similarly, the terms “facing,” “faces” and variations thereof herein are used broadly and encompass direct and indirect facing, and “adjacent to” and variations thereof herein are used broadly and encompass directly and indirectly “adjacent to”. Therefore, the description of “A” component facing “B” component herein may contain the situations that “A” component faces “B” component directly or one or more additional components is between “A” component and “B” component. Also, the description of “A” component “adjacent to” “B” component herein may contain the situations that “A” component is directly “adjacent to” “B” component or one or more additional components is between “A” component and “B” component. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive.
Before the present invention is described in greater detail, it should be noted that similar elements are denoted by the same reference numerals throughout the disclosure.
As shown in
In this embodiment, the image projection apparatus includes three laser arrays 21 and three reflecting units 22. Each of the reflecting units 22 corresponds to a respective one of the laser arrays 21. One of the laser arrays 21 and the corresponding one of the reflecting units 22 are illustrated in
Referring to
Each of the reflecting units 22 has a plurality of reflecting surfaces 222 that are non-parallel to each other, and that are disposed to receive and reflect the laser beams emitted by the laser units 211 of the corresponding one of the laser arrays 21. Each of the reflecting surfaces 222 reflects the laser beams emitted by a corresponding one of the laser units 211 in a distinct direction, such that the laser beams reflected by the reflecting surfaces 222 are incident on the diffusing member 26 at a location of convergence.
According to the first preferred embodiment, each of the reflecting units 22 includes a main body 221, and the reflecting surfaces 222 are spaced at intervals and are formed on one side of the main body 221 facing the laser arrays 21.
Another implementation of the reflecting units 22′ according to a second preferred embodiment of the present invention is shown in
Each of the reflecting units 22′ includes a plurality of main bodies 223 that are spaced apart from each other. Three main bodies 223 are included in this embodiment for illustration purposes. Each of the reflecting surfaces 222 is formed on one side of a corresponding one of the main bodies 223 facing the laser arrays 21. The reflecting surfaces 222 are non-parallel to each other, and are disposed to receive and reflect the laser beams emitted by the laser units 211 of the corresponding one of the laser arrays 21 in distinct directions.
Alternatively, as shown in
Each of the reflecting units 22 has a plurality of reflecting surfaces 222 that are non-parallel to each other, and that are disposed to receive and reflect the laser beams emitted by the laser units 211 of the corresponding one of the laser arrays 21′. The reflecting surfaces 222 reflect the laser beams emitted by corresponding ones of the laser units 211 in distinct directions, such that the laser beams reflected by the reflecting surfaces 222 are incident on the diffusing member 26 at a location of convergence.
It should be noted herein that the 2×3 matrix can be divided into three columns, each including two of the laser units 211 that are arranged in a vertical direction. The laser beams emitted by the laser units 211 of each of the columns and reflected by the corresponding reflecting surface 222 are incident on the diffusing member 26 at two different points of convergence. It is only necessary to ensure that the two points be close together and fall within a relatively small area.
Referring back to
With reference to
As shown in
The lens unit 30 is disposed to receive the uniformized illumination beam from the light uniformizing unit 27 for adjusting a cross-sectional area of the uniformized illumination beam. The light valve 31 is disposed to receive and modulate the adjusted and uniformized illumination beam from the lens unit 30 so as to form an image light beam. The projection lens 32 is disposed to project the image light beam from the light valve 31 onto a screen 33 so as to form an image (not shown). In this embodiment, the lens unit 30 is disposed between the light uniformizing unit 27 and the light valve 31. The lens unit 30 includes a pair of lenses that are different from each other in focal length for adjusting the cross-sectional area of the uniformized illumination beam. The light valve 31 may be a transmissive liquid crystal display (LCD) or a reflective liquid crystal device (e.g., a digital light processor (DLP) and a liquid crystal on silicon (LCOS)).
According to the fourth preferred embodiment of the present invention, the image projection apparatus may be arranged as illustrated in
In sum, by diffusing the laser beams reflected by the reflecting surfaces 222 of the reflecting units 22, 22′ to form the illumination beam prior to entering the light uniformizing unit 27, it is ensured that the uniformized illumination beam exiting the light uniformizing unit 27 has a uniform intensity distribution. This not only enhances the image quality of the image light beam produced by the light valve 31, the need to increase the length of the light uniformizing unit 27 (e.g., an integration rod) is also eliminated.
In addition, by further including the actuating units 23 that are operable to drive movement of the reflecting units 22 relative to the diffusing member 26 for causing reciprocating movement of the laser beams that are reflected by the reflecting surfaces 222 of the reflecting units 22 and that are incident upon the diffusing member 26 at a predetermined frequency, coherence inherent in the laser beams is destroyed, thereby preventing the formation of speckles on the light valve 31 that adversely affect the image quality of the image light beam produced by the light valve 31.
The foregoing description of the preferred embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form or to exemplary embodiments disclosed. Accordingly, the foregoing description should be regarded as illustrative rather than restrictive. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiments are chosen and described in order to best explain the principles of the invention and its best mode practical application, thereby to enable persons skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use or implementation contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents in which all terms are meant in their broadest reasonable sense unless otherwise indicated. Therefore, the terms “the invention”, “the present invention” or the like do not necessarily limit the claim scope to a specific embodiment, and the reference to particularly preferred exemplary embodiments of the invention does not imply a limitation on the invention, and no such limitation is to be inferred. The invention is limited only by the spirit and scope of the appended claims. The abstract of the disclosure is provided to comply with the rules requiring an abstract, which will allow a searcher to quickly ascertain the subject matter of the technical disclosure of any patent issued from this disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Any advantages and benefits described may not apply to all embodiments of the invention. It should be appreciated that variations may be made in the embodiments described by persons skilled in the art without departing from the scope of the present invention as defined by the following claims. Moreover, no element or component in the present disclosure is intended to be dedicated to the public regardless of whether the element or component is explicitly recited in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 096127528 | Jul 2007 | TW | national |
