Patent Publication Number: US-2022221679-A1

Title: Fixing structure and projection apparatus using the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the priority benefit of China application serial no. 202120065420.3, filed on Jan. 12, 2021. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a fixing structure and a projection apparatus, and more particularly to a fixing structure capable of fixing an optical device and a projection apparatus using the fixing structure. 
     Description of Related Art 
     Common optical devices, such as lenses, may be fixed in an optical machine of a projector in the following ways. 
     One way is to dispense an adhesive on the adhesive groove of the lens carrier to fix the lens. 
     Another way is to first assemble the lens on the engine base of the optical machine, and then dispense an adhesive on the adhesive groove on the base to fix the lens. 
     Another method is to first assemble the lens with the lens carrier and the cover, and then fix the lens on the engine base of the optical machine by screwing. 
     From the above, it may be seen that there are many ways to fix the lens. However, using the above methods to fix the lens on a smaller-sized projection product increases the overall size of the product or increases the difficulty of the operation. 
     The information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Further, the information disclosed in the Background section does not mean that one or more problems to be resolved by one or more embodiments of the invention was acknowledged by a person of ordinary skill in the art. 
     SUMMARY OF THE INVENTION 
     The invention provides a fixing structure that is simple in structure and may reduce the use of parts. 
     The invention provides a projection apparatus that may simplify parts and manufacturing processes at the same time. 
     Other objects and advantages of the invention may be further understood from the technical features disclosed in the invention. 
     In order to achieve one or part or all of the above objects or other objects, an embodiment of the invention provides a fixing structure configured to fix an optical device. The fixing structure has an inner wall and a first rib. The inner wall forms a through hole around a central axis. The first rib is disposed at the inner wall and protruded from the inner wall toward the central axis along a radial direction of the through hole. An extending direction of the first rib is parallel to the central axis. When the optical device is placed in the through hole, the first rib interferes with the optical device so that the optical device is fixed in the through hole. 
     In order to achieve one or part or all of the above objects or other objects, an embodiment of the invention provides a projection apparatus including an illumination system, a light valve, and a projection lens. The illumination system is configured to provide an illumination beam, and the illumination system includes a light source, a fixing structure, and an optical device. The fixing structure has an inner wall and a first rib. The inner wall forms a through hole around a central axis. The first rib is disposed at the inner wall, and the first rib is protruded from the inner wall toward the central axis along a radial direction of the through hole. An extending direction of the first rib is parallel to an axial direction of the central axis. The optical device is placed in the through hole, and the first rib interferes with the optical device so that the optical device is fixed in the through hole. The light source illuminates the optical device to form an illumination beam. The light valve is located on a transmission path of the illumination beam and is configured to convert the illumination beam into an image beam. The projection lens is located on a transmission path of the image beam and is configured to project the image beam. 
     Based on the above, in the fixing structure of the invention, by providing ribs at the inner wall, the optical device may be fixed in the through hole of the fixing structure without using other additional parts. Therefore, for the projection apparatus using this fixing structure, the parts for assembly may be reduced, and the assembly process may be simplified at the same time. 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
         FIG. 1  is a schematic diagram of a projection apparatus of an embodiment of the invention. 
         FIG. 2  is a partial schematic diagram of the fixing structure and the optical device in  FIG. 1 . 
         FIG. 3  is a partial schematic diagram of the fixing structure of  FIG. 2  from different perspectives. 
         FIG. 4  is a partial schematic diagram of the fixing structure of  FIG. 2  from another perspective. 
         FIG. 5  is a partial schematic diagram of the fixing structure and the optical device of another embodiment of the invention. 
         FIG. 6  is a partial schematic diagram of the fixing structure of  FIG. 5  from another perspective. 
         FIG. 7  is a schematic partial cross-sectional view along line A-A of  FIG. 6 . 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
     In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings which form a part hereof, and in which 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 may 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 is 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 directly faces “B” component or one or more additional components are 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 are between “A” component and “B” component. Accordingly, the drawings and descriptions will be regarded as illustrative in nature and not as restrictive. 
       FIG. 1  is a schematic diagram of a projection apparatus of an embodiment of the invention.  FIG. 2  is a partial schematic diagram of the fixing structure and the optical device in  FIG. 1 .  FIG. 3  is a partial schematic diagram of the fixing structure of  FIG. 2  from different perspectives. Please refer to  FIG. 1 ,  FIG. 2 , and  FIG. 3  at the same time. 
     A projection apparatus  1  of the invention includes an illumination system  2 , a light valve  3 , and a projection lens  4 . The illumination system  2  is configured to provide an illumination beam L 1 . The light valve  3  is located on a transmission path of the illumination beam L 1  and configured to convert the illumination beam L 1  into an image beam L 2 . The projection lens  4  is located on the transmission path of the image beam L 2  and configured to project the image beam L 2  to display an image on a screen, a wall, or other projection targets. For example, the light valve  3  is, for example, a reflective light modulator such as a digital micro-mirror device (DMD) or a liquid crystal on silicon (LCoS) panel. In some embodiments, the light valve  3  may be, for example, a transmissive light modulator such as a liquid crystal display panel, an electro-optical modulator, a magneto-optic modulator, or an acousto-optic modulator (AOM). However, the content of the disclosure does not limit the configuration and type of the light valve  3 . For example, the projection lens  4  includes a combination of one or a plurality of non-planar optical lenses with refractive power, such as various combinations including non-planar lenses such as biconcave lenses, biconvex lenses, concave-convex lenses, convex-concave lenses, plano-convex lenses, and plano-concave lenses. In an embodiment, the projection lens  4  may also include a flat optical lens to project the image beam L 2  from the light valve  3  out of the projection apparatus  1  in a reflective or transmissive manner. The content of the disclosure does not limit the configuration and type of the projection lens  4 . 
     The illumination system  2  includes a light source  21 , a fixing structure  22 , and an optical device  23 . The fixing structure  22  and the optical device  23  are disposed between the light source  21  and the light valve  3 . In detail, the projection apparatus  1  has a base  20  (as indicated in  FIG. 2  and  FIG. 3 ), and the fixing structure  22  is disposed at the base  20 . 
     The fixing structure  22  has an inner wall  221  and a first rib  222 . The inner wall  221  forms a through hole H around a central axis C, so that the central axis C is the central axis of the through hole H. The first rib  222  is disposed at the inner wall  221 , wherein the first rib  222  is protruded from the inner wall  221  toward the central axis C along the radial direction of the through hole H, and the extending direction of the first rib  222  is parallel to the axial direction of the central axis C. Specifically, the height of the first rib  222  protruded from the inner wall  221  toward the central axis C along the radial direction of the through hole H is the thickness of the first rib  222 , the distance that the first rib  222  is extended in an axial direction parallel to the central axis C is a length L of the first rib  222 , and the size of the first rib  222  distributed along the circumferential direction of the through hole H is an arc length A 1  of the first rib  222 . 
     The optical device  23  is placed in the through hole H. The optical device  23  of the embodiment is a lens, and the light source  21  irradiates the optical device  23  to form the illumination beam L 1 . When the optical device  23  is placed in the through hole H, the first rib  222  located in the inner wall  221  interferes with the optical device  23  so that the optical device  23  is fixed in the through hole H. 
     In an embodiment, providing only one first rib  222  may achieve the object of interfering with the optical device  23  in the through hole H to fix the optical device  23  in the through hole H. In this case, before the optical device  23  is fixed in the through hole H, the optical axis of the optical device  23  is not overlapped with the central axis C of the through hole H. However, by disposing one first rib  222 , the optical device  23  may be fixed at a position where the optical axis of the optical device  23  is overlapped with the central axis C of the through hole H, so as to achieve a good beam transmission effect. 
       FIG. 4  is a partial schematic diagram of the fixing structure of  FIG. 2  from another perspective. Please refer to  FIG. 2 ,  FIG. 3 , and  FIG. 4  at the same time. It should be mentioned that, when only one first rib  222  is disposed, the fixing structure  22  may further have a positioning boss  223  disposed at the inner wall  221 , wherein the positioning boss  223  is extended along the circumferential direction of the through hole H and protruded from the inner wall  221  toward the central axis C along the radial direction of the through hole H. 
     Furthermore, the positioning boss  223  and the first rib  222  are disposed at an equal angle around the central axis C. For example, in the embodiment shown in  FIG. 4 , the number of the first rib  222  is one, and the number of the positioning boss  223  is also one. In this case, the positioning boss  223  and the first rib  222  are disposed at an angle of 180 degrees. That is, with the central axis C as the center of the through hole H, the positioning boss  223  and the first rib  222  are located at two opposite sides of the central axis C in the radial direction of the through hole H. Since the first rib  222  and the positioning boss  223  are disposed at an angle of 180 degrees, the first rib  222  and the positioning boss  223  interfere with the optical device  23  at a symmetrical angle and with a more uniform force. In this way, the optical device  23  is not readily skewed and may be more stably fixed in the through hole H. In other embodiments, the number of the first rib  222  is one, but the number of the positioning boss  223  may be a plurality. Taking two positioning bosses  223  as an example, the condition that the positioning bosses  223  and the first rib  222  are disposed at an equal angle around the central axis C needs to be satisfied. One first rib  222  and two positioning bosses  223  may be disposed at an angle of 120 degrees (not shown in the figure) to provide a more uniform force to the optical device  23  so that the optical device  23  may be more stably fixed in the through hole H. 
     In view of the above, the height of the positioning boss  223  from the inner wall  221  toward the central axis C along the radial direction of the through hole H does not need to be too high, and may be slightly greater than, equal to, or slightly less than the thickness of the first rib  222 . The height (thickness) of the first rib  222  and the positioning boss  223  from the inner wall  221  toward the central axis C along the radial direction of the through hole H may be changed adaptively according to the size of the lens. In addition, along the circumferential direction of the through hole H, an arc length A 2  of the positioning boss  223  is greater than the arc length A 1  of the first rib  222  to improve the stability of fixing the optical device  23  in the through hole H. In other embodiments, when the number of the positioning boss  223  is a plurality, the arc length A 2  may be regarded as the total arc length A 2  of the plurality of positioning bosses  223 , and it is only necessary to make the total arc length A 2  greater than the arc length A 1  of the first rib  222 . At this time, the arc length of a single positioning boss  223  does not necessarily need to be greater than the arc length A 1  of the first rib  222 . More specifically, the position and size of the first rib  222  and the positioning boss  223  should be set to fix the optical device  23  at a position where the optical axis of the optical device  23  is overlapped with the central axis C of the through hole H to achieve a good beam transmission effect. 
     It may be seen from the above that the first rib  222  and the positioning boss  223  interfere with the optical device  23  along the radial direction of the through hole H, thereby stably fixing the optical device  23  in the through hole H. In this way, there is no need to fix the optical device  23  using adhesive or locking, thus not only reducing the use of assembly parts (holder, cover, and screws), but also simplifying the assembly process. Moreover, since mechanical interference is used instead of an adhesion method, if there is an issue in assembly, rework may be done conveniently and simply without damaging the fixing structure  22  or the optical device  23 . 
       FIG. 5  is a partial schematic diagram of the fixing structure and the optical device of another embodiment of the invention. In order to make the optical device  23  evenly stressed and more stably fixed in the through hole H, in the embodiment shown in  FIG. 5 , the number of the first rib  222  may also be set to a plurality (three first ribs  222  are exemplarily shown in  FIG. 5 ), and the first ribs  222  are disposed at an equal angle around the central axis C. When the number of the first rib  222  is a plurality and the first ribs  222  are disposed at an equal angle around the central axis C, the positioning boss  223  may be omitted. Of course, when the number of the first rib  222  is a plurality, the positioning boss  223  may also be disposed according to requirements, and the positioning boss  223  and the first ribs  222  are staggered in the circumferential direction of the through hole H (not shown). 
       FIG. 6  is a partial schematic diagram of the fixing structure of  FIG. 5  from another perspective.  FIG. 7  is a schematic partial cross-sectional view along line A-A of  FIG. 6 . It should be noted that, in order to clearly show the internal structure of the fixing structure, the optical device is omitted in  FIG. 6  and  FIG. 7 . Referring to  FIG. 6  and  FIG. 7  at the same time, the fixing structure  22  further has a first surface  22   a  and a second surface  22   b , wherein the inner wall  221  is connected between the first surface  22   a  and the second surface  22   b . The optical device  23  is inserted into the through hole H along a direction D from the first surface  22   a  toward the second surface  22   b . The fixing structure  22  further has a second rib  224 , wherein the second rib  224  is also disposed at the inner wall  221 . Different from the first rib  222 , the second rib  224  is disposed to be extended along the circumferential direction of the through hole H and protruded from the inner wall  221  toward the central axis C along the radial direction of the through hole H to stop the optical device  23 . More specifically, when the optical device  23  is assembled to the through hole H from the first surface  22   a  toward the second surface  22   b , the arrangement of the second rib  224  may be used to limit the assembly distance of the optical device  23  to prevent the assembler from applying excessive force to cause the optical device  23  to fall off from the second surface  22   b.    
     The number of the second rib  224  is a plurality, and the second ribs  224  are disposed at an equal angle around the central axis C. Disposing the plurality of second ribs  224  at an equal angle may prevent the optical device  23  from being skewed during mounting and positioning. In addition, the first ribs  222  and the second ribs  224  are angularly staggered around the central axis C. In other words, the first ribs  222  and the second ribs  224  are staggered in the circumferential direction of the through hole H. For example, the first ribs  222  are provided at 0 degrees, 120 degrees, and 240 degrees, and the second ribs  224  are provided at 60 degrees, 180 degrees, and 300 degrees. The advantage of this arrangement is that when the mold configured to form the first ribs  222  or the second ribs  224  needs to be repaired, the mold maintenance is more convenient. 
     In another embodiment, the second ribs  224  may also be provided as only one and formed around the entire inner wall  221  (not shown). 
     In the embodiment, a surface  224   a  of the second ribs  224  connected to the inner wall  221  may be an inclined surface inclined with respect to the inner wall  221 . The inclined surface is configured to stop the curved portion of the edge of the optical device that is the lens. 
     However, in another embodiment, the surface  224   a  of the second ribs  224  connected to the inner wall  221  may be flat. The form in which the surface  224   a  of the second ribs  224  is connected to the inner wall  221  is not limited and may be adjusted according to requirements. 
     The positioning boss  223  and the second ribs  224  may be optionally provided according to requirements. Specifically, the positioning boss  223  may be omitted and the second ribs  224  are provided; or the positioning boss  223  may be provided and the second ribs  224  are omitted; or the positioning boss  223  and the second ribs  224  may be provided at the same time; or the positioning boss  223  and the second ribs  224  may be omitted, and only the first ribs  222  are provided. It should be noted that in the embodiment shown in  FIG. 4 , the fixing structure  22  also has the second ribs  224 , wherein the positioning boss  223  and the second ribs  224  are provided at the same time, and the thickness of the second ribs  224  protruded from the inner wall  221  is greater than the thickness of the positioning boss  223  protruded from the inner wall  221 . In addition, the positioning boss  223  may be connected to one of the second ribs  224 , and in this case, the positioning boss  223  is extended from the first surface  22   a  to the second rib  224  along the axial direction of the central axis C. 
     In other embodiments, the positioning boss  223  and the second ribs  224  may be angularly staggered around the central axis C. That is, along the axial direction of the central axis C, the positioning boss  223  is not directly connected to any of the second ribs  224  (not shown). 
     Returning to  FIG. 6  and  FIG. 7 , the fixing structure  22  further has a plurality of bosses  225 , wherein the bosses  225  are disposed at the first surface  22   a  and disposed at an equal angle around the central axis C. During assembly, when the top of the fixture touches the first surface  22   a , the automated assembly system knows that the positioning point for the assembly of the optical device  23  is reached. 
     Moreover, in the embodiment, the number of the bosses  225  is four, the four bosses  225  form a limiting area B, and the light source  21  (not shown) is correspondingly disposed in the limiting area B to emit light on the optical device  23 . 
     When the assembler assembles the optical device  23  to the fixing structure  22 , the optical device  23  is inserted into the through hole H along the direction D from the first surface  22   a  of the fixing structure  22  toward the second surface  22   b  of the fixing structure  22 . At this time, the first ribs  222  interfere with the optical device  23 , so the assembler applies force to push the optical device  23  to fix the optical device  23  in the through hole H. In addition, in some embodiments, the optical device  23  may be more stably fixed in the through hole H by the interference of the positioning boss  223  on the optical device  23 . 
     The second ribs  224  may act as a stopper to limit the axial movement distance of the optical device  23  along the central axis C in the through hole H to prevent the optical device  23  from falling off from the second surface  22   b  due to excessive force by the assembler. 
     Incidentally, in order to achieve functions such as guiding light or improving resolution, the projection apparatus  1  may also include other optical apparatuses. The optical apparatuses may be selected according to actual needs. 
     Based on the above, the fixing structure of the invention and the projection apparatus using the fixing structure have the following advantages: 
     1. The invention uses interference to achieve the effect of assembling and fixing the optical device. Not only are the adhesive dispensing cost and adhesive dispensing man-hours required by the known fixing solution not needed, but the pollution of other parts caused by the colloid used in the known fixing solution may also be avoided. Therefore, the remaining parts may be kept clean. In addition, the issue of contaminating the optical device due to a colloid exerted by light irradiation may be avoided. Moreover, advantages such as simple and convenient rework without destructive influence on the optical device or the fixing structure and maintaining the integrity of the optical device and the fixing structure may also be achieved. 
     2. Compared with the known method of using screws to fix the optical device, screwless assembly of the optical device and the fixing structure in the invention may be achieved, thus reducing the use of parts and assembly man-hours, and may also achieve the effect of reducing accumulated tolerances. Moreover, it is only necessary to insert the optical device into the through hole formed by the inner wall of the fixing structure along the assembly direction, thus achieving the advantages of simple and convenient assembly method. 
     3. The volume of parts may be reduced, or related parts used to fix optical device may be reduced, thereby minimizing the volume of the projection apparatus. 
     4. The assembly of the optical device and the fixing structure in the invention may simplify the manufacturing process of assembling the lens, and therefore automatic assembly may be readily introduced. 
     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 term “the invention”, “the present invention” or the like does 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. Moreover, these claims may refer to use “first”, “second”, etc. following with noun or element. Such terms should be understood as a nomenclature and should not be construed as giving the limitation on the number of the elements modified by such nomenclature unless specific number has been given. 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 and 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.