OPTICAL ACTUATOR AND IMAGING DEVICE

An optical actuator includes a base, a light-transmitting plate, a frame, a plurality of suspension members, and a plurality of actuation members. The base has a mounting surface. The light-transmitting plate is located above the mounting surface. The frame frames an outer edge of the light-transmitting plate. The frame retreats inwardly relative to the mounting surface, so that the mounting surface has a plurality of disposing areas relative to the frame. The suspension members are respectively located on the disposing areas and connected between the base and the frame. The actuation members are respectively located on the disposing area and configured to drive the frame to reciprocate relative to the mounting surface.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to China Application Serial Number 202311060967.4, filed Aug. 22, 2023, which is herein incorporated by reference.

BACKGROUND

Technical Field

The present disclosure relates to an optical actuator and an imaging device.

Description of Related Art

A projector is a display device used to produce large-size images. The imaging principle of the projector is to use the light valve module to convert the illumination beam generated by the light source module into an image beam, and then project the image beam onto the screen or wall through the projection lens.

In order to improve the pixel quality of the projected images, some projectors have an optical actuator installed between the light valve module and the projection lens, and the vibration of the optical actuator causes the pixels to reciprocate appropriately to prevent the pixel particles in the projected images from being too obvious. Specifically, when the light generated by the light source module is modulated by the light valve module, the light is then transmitted to the projection lens through the optical actuator.

However, existing optical actuators are large in size, so when used with projection lenses with partial focal lengths (for example, projection lenses with short back focus distances), the spaces between the prisms and the projection lenses are often limited and thus the problem of structural interference is encountered, which makes the optical actuators cannot be used.

Accordingly, how to provide optical actuator and an imaging device that can solve the aforementioned problems becomes an important issue to be solved by those in the industry.

SUMMARY

An aspect of the disclosure is to provide an optical actuator and an imaging device.

According to an embodiment of the disclosure, an optical actuator includes a base, a light-transmitting plate, a frame, a plurality of suspension members, and a plurality of actuation members. The base has a mounting surface. The light-transmitting plate is located above the mounting surface. The frame frames an outer edge of the light-transmitting plate. The frame retreats inwardly relative to the mounting surface, so that the mounting surface has a plurality of disposing areas relative to the frame. The suspension members are respectively located on the disposing areas and connected between the base and the frame. The actuation members are respectively located on the disposing areas and configured to drive the frame to reciprocate relative to the mounting surface.

In one or more embodiments of the present disclosure, one of the suspension members and one of the actuation members on one of the disposing areas are arranged in a normal direction of the mounting surface.

In one or more embodiments of the present disclosure, the actuation members are configured to drive the frame to reciprocate relative to the mounting surface along the normal direction.

In one or more embodiments of the present disclosure, the disposing areas are respectively located at four corners of the base.

In one or more embodiments of the present disclosure, two of the actuation members are arranged along a first diagonal axis. Other two of the actuation members are arranged along a second diagonal axis. The first diagonal axis and the second diagonal axis are perpendicular to each other.

According to an embodiment of the disclosure, an imaging device includes a light valve module, an optical actuator, and a plurality of prisms. The optical actuator includes a base, a light-transmitting plate, a frame, a plurality of suspension members, and a plurality of actuation members. The base has a mounting surface. The light-transmitting plate is located above the mounting surface. The frame frames an outer edge of the light-transmitting plate. The frame retreats inwardly relative to the mounting surface, so that the mounting surface has a plurality of disposing areas relative to the frame. The suspension members are respectively located on the disposing areas and connected between the base and the frame. The actuation members are respectively located on the disposing area and configured to drive the frame to reciprocate relative to the mounting surface. The prisms are optically coupled between the light valve module and the light-transmitting plate.

In one or more embodiments of the present disclosure, one of the suspension members and one of the actuation members on one of the disposing areas are arranged in a normal direction of the mounting surface.

In one or more embodiments of the present disclosure, the actuation members are configured to drive the frame to reciprocate relative to the mounting surface along the normal direction.

In one or more embodiments of the present disclosure, the disposing areas are respectively located at four corners of the base.

In one or more embodiments of the present disclosure, two of the actuation members are arranged along a first diagonal axis. Other two of the actuation members are arranged along a second diagonal axis. The first diagonal axis and the second diagonal axis are perpendicular to each other.

In one or more embodiments of the present disclosure, the first diagonal axis extends through two of the disposing areas. The second diagonal axis extends through other two of the disposing areas.

In one or more embodiments of the present disclosure, the light valve module has a length axis and a width axis respectively parallel to the first diagonal axis and the second diagonal axis.

In one or more embodiments of the present disclosure, the base further has a side surface connected to the mounting surface. The side surface is connected to two of the disposing areas. The prisms include a first prism and a second prism. The first prism is located between the light valve module and the light-transmitting plate. The second prism is partially located between the light valve module and the first prism and extends to a side of the side surface to form a gap with the side surface.

In one or more embodiments of the present disclosure, one of the suspension members has a first fixing end and a second fixing end, and is fixed to the base and the frame respectively through the first fixing end and the second fixing end.

In one or more embodiments of the present disclosure, the one of the suspension members includes two ribs. Two ends of each of the ribs are respectively connected to the first fixing end and the second fixing end. The ribs protrude away from each other in opposite directions between the first fixing end and the second fixing end.

Accordingly, in the optical actuator and the imaging device of the present disclosure, by concentrating the suspension members and the actuation members on a plurality of disposing areas of the mounting surface of the base, the area of the mounting surface can be reduced, thereby effectively reducing the volume occupied by the optical actuator in the imaging device. In this way, the applicability of projection lenses with various focal lengths in the imaging device of the present disclosure can be effectively increased.

DETAILED DESCRIPTION

Reference will now be made in detail to the present embodiments of the disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. However, specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments, and thus may be embodied in many alternate forms and should not be construed as limited to only example embodiments set forth herein. Therefore, it should be understood that there is no intent to limit example embodiments to the particular forms disclosed, but on the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

Reference is made toFIGS.1and2.FIG.1is a schematic perspective view of an imaging device100according to an embodiment of the present disclosure.FIG.2is a schematic perspective view of some components of the imaging device100according to an embodiment of the present disclosure. As shown inFIGS.1and2, in the present embodiment, the imaging device100takes a projector as an example, but the present disclosure is not limited thereto. The imaging device100includes a housing110and a plurality of components disposed in the housing110. For example, the imaging device100includes a projection lens120, a light source module (not shown), a light valve module130, an optical actuator200, and a plurality of prisms. The light source module is configured to generate an illumination beam. The prisms are optically coupled between the light source module and the light valve module130, and optically coupled between the light valve module130and the optical actuator200. The illumination beam generated by the light source module first reaches the light valve module130through the prisms. The light valve module130is configured to convert the illumination beam into an image beam. The image beam is projected onto the screen sequentially through the prisms, the optical actuator200, and the projection lens120.

In some embodiments, the light valve module130is a digital micromirror device (DMD), but the present disclosure is not limited thereto. Specifically, when a certain pixel is to display an image, the corresponding micromirror element of the light valve module130causes the image beam converted from the illumination beam to be projected outside the housing110sequentially through the prisms, the optical actuator200, and the projection lens120. When a certain pixel is not expected to display an image, the corresponding micromirror element of the light valve module130causes the image beam to deviate from the optical actuator200after passing through the prisms, so that the image beam cannot be projected outside the housing110through the projection lens120.

As shown inFIG.2, in the present embodiment, the optical actuator200includes a base210, a light-transmitting plate220, a frame230, a suspension bracket240, and a plurality of actuation members250. The base210has a mounting surface212a. The light-transmitting plate220is located above the mounting surface212a. The frame230frames an outer edge of the light-transmitting plate220. The frame230retreats inwardly relative to the mounting surface212a, so that the mounting surface212ahas a plurality of disposing areas212brelative to the frame230. The suspension bracket240includes a plurality of suspension members241. The suspension members241are respectively located on the disposing areas212band connected between the base210and the frame230. The actuation members250are respectively located on the disposing areas212band configured to drive the frame230to reciprocate relative to the mounting surface212a. In detail, the function of the suspension bracket240is to suspend the frame230at a predetermined distance above the mounting surface212aand maintain it parallel. The suspension bracket240also ensures that when the actuation members250drive the frame230to reciprocate, a certain moving space and the ability to elastically return are maintained. The prisms are optically coupled between the light valve module130and the light-transmitting plate220.

It can be clearly seen from the foregoing structural configurations that the suspension members241and the actuation members250are respectively centrally disposed on the disposing areas212bof the mounting surface212aof the base210. Therefore, the area of the mounting surface212acan be reduced, thereby effectively reducing the volume occupied by the optical actuator200in the imaging device100.

As shown inFIG.2, in the present embodiment, the base210includes a bottom plate211and a circuit board212. The circuit board212is disposed on the bottom plate211(e.g., by screws). The bottom plate211is located on a side of the base210facing the light valve module130. The circuit board212is located on a side of the base210away from the light valve module130. The mounting surface212ais the surface of the circuit board212away from the bottom plate211. In some embodiments, the material of the bottom plate211includes metal, thereby improving the overall rigidity of the base210and carrying the circuit board212. The bottom plate211and the circuit board212have hollow structures for allowing the image beam converted by the light valve module130to pass through.

Reference is made toFIG.3.FIG.3is a side view of the components inFIG.2. As shown inFIGS.2and3, in the present embodiment, the base210further has a side surface212cconnected to the mounting surface212a. The side surface212cis connected to two of the disposing areas212b(e.g., the two disposing areas212blocated on the right and lower sides inFIG.2and adjacent to the prisms). In other words, the side surface212cis the surface of the circuit board212facing the prisms. The prisms include a first prism141and a second prism142. The first prism141is located between the light valve module130and the light-transmitting plate220. The second prism142is partially located between the light valve module130and the first prism141and extends to a side of the side surface212cto form a gap G with the side surface212c. Since the suspension members241and the actuation members250are centrally disposed on the disposing areas212bof the mounting surface212a, an edge of the frame230of the optical actuator200close to the second prism142can be closer to the side surface212cof the base210. In this way, the distance between the optical actuator200and the light valve module130can be effectively reduced without structural interference between the optical actuator200and the second prism142, thereby effectively increasing the applicability of the projection lenses120with various focal lengths in the imaging device100of the present disclosure.

As shown inFIG.3, in the present embodiment, the bottom plate211of the base210has a side surface211aadjacent to the second prism142, and the side surface211ais inclined relative to the side surface212cand is substantially parallel to the surface of the second prism142facing the optical actuator200. In this way, the distance between the optical actuator200and the light valve module130can be further reduced.

As shown inFIGS.2and3, in the present embodiment, the suspension member241and the actuation member250located on the same disposing area212bare arranged in a normal direction N of the mounting surface212a, which causes the action direction of the actuation member250and the elastically returning direction of the corresponding suspension member241to move in the same normal direction N. It can be seen from this that each set of the suspension members241and actuation members250actually move in the same disposing areas212bon the mounting surface212a. Therefore, there are many positions around the frame230of the optical actuator200that can be vacated for making room.

Reference is made toFIGS.4and5.FIG.4is a front view of the optical actuator200inFIG.3.FIG.5is another front view of the optical actuator200inFIG.4, in which the suspension bracket240is removed. As shown inFIGS.4and5, in the present embodiment, the disposing areas212bare respectively located at four corners of the base210. Specifically, the mounting surface212aof the base210is substantially rectangular and has four corners. The four corners of the frame230are retracted relative to the mounting surface212a, so that the mounting surface212ahas four disposing areas212brelative to the frame230, and the two lower disposing areas212bare closer to the edge of the base210.

As shown inFIG.5, in the present embodiment, the contour of the outer edge of the frame230that is retracted relative to the mounting surface212ais substantially octagonal, but the disclosure is not limited thereto. In practical applications, the contour of the outer edge of the frame230may be circular.

As shown inFIG.5, in the present embodiment, the frame230of the optical actuator200includes a bottom frame231and a plurality of fixing plates232. The light-transmitting plate220is supported on the bottom frame231. The fixing plates232are fixed on the bottom frame231and respectively abut against different edges of the light-transmitting plate220to tightly fit and fix the light-transmitting plate220. In detail, as shown inFIG.5, the number of fixing plates232is four. The contour of the outer edge of the light-transmitting plate220is substantially octagonal. The fixing plates232are located in two opposite corners of the light-transmitting plate220.

Reference is made toFIG.6.FIG.6is a front view of the suspension bracket240inFIG.4. As shown inFIGS.4and6, in the present embodiment, the suspension bracket240further includes connection bar242. The connection bar242is in a frame shape and connects the suspension members241in series. By connecting the suspension members241in series with the connection bar242, the suspension bracket240can be made into a unitary structure, thereby increasing the convenience of installing the suspension bracket240. Each of the suspension members241has a first fixing end241aand a second fixing end241b. The first fixing end241aand the second fixing end241bare structurally connected to each other and separated by a predetermined distance to maintain structural elasticity. The first fixing end241ais located at an end of the suspension member241away from the connection bar242. The second fixing end241bis located at the junction between the suspension member241and the connection bar242. The suspension member241is fixed to the base210through the first fixing end241a(e.g., by screwing to the bottom plate211of the base210). The suspension member241is fixed to the frame230through the second fixing end241b(e.g., by screwing to the fixing plate232of the frame230). In this way, the suspension bracket240can be connected between the base210and the frame230.

In some embodiments, whether the suspension member241is located in the disposing area212bcan be determined based on whether the first fixing end241ais located in the disposing area212b. As shown inFIGS.4and6, the first fixing ends241aof the four suspension members241are respectively located in the four disposing areas212b, so it can be determined that the suspension members241are respectively located in the four disposing areas212b.

As shown inFIG.6, in the present embodiment, each of the suspension members241includes two ribs. Two ends of each of the ribs are respectively connected to the first fixing end241aand the second fixing end241b, and the ribs protrude away from each other in opposite directions between the first fixing end241aand the second fixing end241b. Furthermore, the two ribs extend to two sides along the line connecting the first fixing end241aand the second fixing end241band are symmetrical, so that the suspension member241forms a symmetrical butterfly wing structure. It should be noted that since the ribs are thinner than the connection bar242, they are easier to elastically deform. In contrast, since the connection bar242is thicker than the ribs, the overall rigidity and stability of the suspension bracket240can be increased.

In practical applications, the connection bar242can be omitted from the suspension bracket240. That is, the suspension bracket240may only include suspension members241that are separated from each other.

Reference is made toFIG.7.FIG.7is a perspective view of the actuation member250inFIG.2. As shown inFIGS.2and7, in the present embodiment, the actuation member250includes a coil251, a magnetic conductive member252, and a magnet253. The coil251is fixed to the base210and electrically connected to the circuit board212. The wire of the coil251is wound substantially parallel to the mounting surface212a. The magnetic conductive member252is fixed to the frame230and partially penetrates into the surrounding space of the coil251(e.g., along the normal direction N shown inFIG.3). The magnet253is fixed to the magnetic conductive member252, and the magnetic force of the magnet253can be transmitted to the magnetic conductive member252. According to the left-hand rule, when the left hand is placed in a magnetic field and the magnetic field lines penetrate vertically into the palm of the hand, the four fingers indicate the direction of positive charge movement, and the direction pointed by the thumb vertical to the four fingers is the direction of the Lorentz force. It can be seen from this that by flowing currents in different directions to the coil251, the Lorentz force can be exerted on the magnetic conductive member252to reciprocate along the normal direction N. In this way, the actuation members250can drive the frame230to reciprocate along the normal direction N relative to the mounting surface212a.

As shown inFIG.2, in the present embodiment, two of the actuation members250(i.e., the upper actuation member250and the lower actuation member250inFIG.2) are arranged along a first diagonal axis DA1. Other two of the actuation members250(i.e., the left actuation member250and the right actuation member250inFIG.2) are arranged along a second diagonal axis DA2. The first diagonal axis DA1and the second diagonal axis DA2are perpendicular to each other. Furthermore, the disposing areas212b, the suspension members241with the first fixing ends241aand the second fixing ends241bthereof, and the actuation members250are arranged in the first diagonal axis DA1or the second diagonal axis DA2. The first diagonal axis DA1extends through the upper and lower disposing areas212binFIG.2. The second diagonal axis DA2extends through the left and right disposing areas212binFIG.2. These actuation members250can actuate sequentially in time sequence. When these actuation members250actuate sequentially, the optical axis of the light-transmitting plate220can be deflected toward different directions respectively. In this way, the image beam passing through the light-transmitting plate220can produce a pixel shift effect, and the image resolution can be improved after signal synchronization. For example, the original resolution of 1920*1080 can be increased to 3840*2160, but the present disclosure is not limited thereto.

As shown inFIG.2, in the present embodiment, the light valve module130has a length axis AL and a width axis AW. The length axis AL and the width axis AW are respectively parallel to the first diagonal axis DA1and the second diagonal axis DA2. With the configurations, the image beam with the light valve module130in the ON state can effectively pass through the light-transmitting plate220, and the image beam can produce a predetermined pixel shift effect.

According to the foregoing recitations of the embodiments of the disclosure, it can be seen that in the optical actuator and the imaging device of the present disclosure, by concentrating the suspension members and the actuation members on a plurality of disposing areas of the mounting surface of the base, the area of the mounting surface can be reduced, thereby effectively reducing the volume occupied by the optical actuator in the imaging device. In this way, the applicability of projection lenses with various focal lengths in the imaging device of the present disclosure can be effectively increased.