Abstract:
A control method of a projection device is disclosed. The control method includes following steps: entering at least one projection mode; detecting at least one motion trace of the projection device; adjusting at least one swing angle of a scan unit of the projection device according to at least one motion trace to adjust a projection scope that the projection device projects on a projection surface.

Description:
[0001]    This application claims the benefit of People&#39;s Republic of China application Serial No. 201410081730.9, filed Mar. 6, 2014, the subject matter of which is incorporated therein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates in general to a projection device and a control method thereof, and more particularly to a projection device capable of adjusting the projection range and a control method thereof. 
         [0004]    2. Description of the Related Art 
         [0005]    The projection device, particularly the scan type projection device using laser light source, normally does not perform focusing. The swing range of the scan unit of the scan type projection device is normally fixed, and so is the corresponding projection scope that the projection device projects on the projection surface if the projection device is placed at a fixed position. If the projection scope needs to be adjusted, the adjustment normally can be achieved by adjusting the distance between the projection device and the projection surface. In addition to the distance between the projection device and the projection surface, the projection scope is also affected by the inclination or rotation of the projection device. Therefore, how to provide a method for adjusting the projection scope to enhance the convenience of use has become a prominent task for the industries. 
       SUMMARY OF THE INVENTION 
       [0006]    The invention is directed to a projection device and a control method thereof. 
         [0007]    According to one embodiment of the present invention, a control method of a projection device is disclosed. The control method includes following steps: entering at least one projection mode; detecting at least one motion trace of the projection device; adjusting at least one swing angle of a scan unit of the projection device according to at least one motion trace to adjust a projection scope that the projection device projects on a projection surface. 
         [0008]    According to another embodiment of the present invention, a projection device is disclosed. The projection device includes a light source module, a motion detection module, and a controller. The light source module emits an image beam. The motion detection module detects at least one motion trace of the projection device. The controller adjusts a projection scope that the projection device projects on a projection surface according to at least one motion trace. 
         [0009]    The above and other aspects of the invention will become better understood with regard to the following detailed description of the preferred but non-limiting embodiment (s). The following description is made with reference to the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a block diagram of a projection device according to an embodiment of the present invention. 
           [0011]      FIG. 2  is a schematic diagram of rotation and inclination of a projection device. 
           [0012]      FIG. 3  is a flowchart of a control method of a projection device according to an embodiment of the present invention. 
           [0013]      FIG. 4  is a schematic diagram of a projection device at an initial position. 
           [0014]      FIG. 5  is a schematic diagram of the inclined projection device of  FIG. 4 . 
           [0015]      FIG. 6  is a schematic diagram before and after a projection device is displaced. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0016]      FIG. 1  is a block diagram of a projection device according to an embodiment of the present invention. The projection device  100  includes a light source module  10 , a scan projection module  11 , a motion detection module  12  and a controller  14 . The light source module  10  emits an image beam to the scan projection module  11 . The scan projection module  11  scans and projects the image beam onto a projection surface. The motion detection module  12  detects a motion trace of the projection device  100 . The controller  14  adjusts a swinging range of the scan projection module  11  and, therefore, adjusts a projection scope that the projection device  100  projects on the projection surface according to the motion trace. In the present embodiment, the motion trace detected by the motion detection module  12  includes a motion direction and a motion magnitude. The motion magnitude can be defined as a rotation angle or a displacement according to the motion state (rotation or displacement) of the projection device. 
         [0017]    In the present embodiment, the scan projection module  11  includes a scan unit  112 . The scan unit  112  can swing in a first direction and swing in a second direction to drive the image beam to scan back and forth on the projection surface to generate a projection image. The scan unit  112  can be realized by a dual-axis scanning mirror or two single-axis scanning mirrors. The scan unit  112  can be realized by a micro-electro-mechanical system (MEMS) scanning mirror. In the present embodiment, the scan unit  112  swings in the first direction at a first swing angle and swings in the second direction at a second swing angle. The projection scope of the projection device  100  on the projection surface is associated with to the first swing angle and the second swing angle. 
         [0018]      FIG. 2  is a schematic diagram of rotation and inclination of a projection device. In the present embodiment, the motion detection module  12  includes an angle detection unit  122 , such as a gyroscope. The motion detection module  12  detects a first motion trace of the projection device  100 . The first motion trace includes a first direction and a first rotation angle. The first direction is such as direction D 1 , and the first rotation angle is such as angle θ. The motion detection module  12  further detects a second motion trace of the projection device  100 . In other words, the angle detection unit  122  detects the first rotation angle θ of the projection device  100  in the first direction D 1  as well as a second rotation angle φ of the projection device  100  in a second direction D 2 . Refer to  FIG. 2 . Suppose the x-axis direction of  FIG. 2  is perpendicular to the projection surface which is parallel to the yz plane, then the rotation of the projection device  100  in the space can be defined as the first rotation angle θ and the second rotation angle φ, wherein the first rotation angle θ is the angle that the projection device  100  rotates about the y-axis, and the second rotation angle φ is the angle that the projection device  100  rotates about the z-axis. In the present embodiment, the rotation of the projection device  100  in the first direction D 1  and that in the second direction D 2  are associated with the swing of the scan unit  112  in the first direction and that in the second direction respectively. 
         [0019]    The controller  14  adjusts the first swing angle α at which the scan unit  112  swings about the y-axis in the first direction according to the first rotation angle θ in the first direction D 1  so as to adjust the first boundary position of the projection scope on the projection surface corresponding to the first direction D 1 . The first boundary position of the projection scope corresponding to the first direction D 1  is, for example, at least one of a top boundary position and a bottom boundary position of the projection scope on the projection surface. The first swing angle α is, for example, coplanar with the first rotation angle θ. The controller  14  further adjusts the second swing angle β at which the scan unit  112  swings about the z-axis in the second direction according to the second rotation angle φ in the second direction D 2  so as to adjust the second boundary position of the projection scope on the projection surface corresponding to the second direction D 2 . The second direction D 2  is different from the first direction D 1 . The second boundary position of the projection scope corresponding to the second direction D 2  is, for example, at least one of a right boundary position and a left boundary position of the projection scope on the projection surface. The second swing angle β, for example, coplanar with the second rotation angle φ. 
         [0020]    In the present embodiment, the motion detection module  12  further includes a displacement detection unit  124  to detect a third motion trace of the projection device  100 . The third motion trace includes a third direction and a displacement. In other words, the displacement detection unit  124  detects a displacement of the projection device  100  in a third direction. Preferably, the third direction is perpendicular to the projection surface. The controller  14  further adjusts the first swing angle α and/or the second swing angle β at which the scan unit  112  swings in the first direction and/or the second direction according to the displacement in the third direction so as to adjust the projection scope of the projection device on the projection surface. For example, the controller  14  reduces or increases the swinging range of the scan unit  112  as the projection device  100  moves away from or gets close to the projection surface so as to adjust the projection scope on the projection surface to be fixed. 
         [0021]    In the present embodiment, the motion detection module  12  detects at least one motion trace of the projection device  100 , and the controller  14  adjusts at least one swing angle of the scan unit  112  according to the detected one or more motion traces so as to adjust the projection scope on the projection surface. In the present embodiment, the controller  14  adjusts the swinging range to project a fixed projection scope and/or a controllable projection scope on the projection surface according to the detected motion trace(s). Adjusting the swinging range to project the fixed projection scope means the controller  14  reverses the changed projection scope caused by the rotation or displacement of the projection device  100  to the original projection scope, such that the projection scope on the projection surface remains fixed. Adjusting the swinging range to project the controllable projection scope means the controller  14  regards the motion trace of the rotation or displacement of the projection device  100  as a control command for controlling the projection scope on the projection surface, and adjusts the swinging range to control the projection scope. 
         [0022]    In the present embodiment, the controller  14  selectively adjusts the swinging range to project a fixed projection scope or a controllable projection scope according to the projection mode. In the present embodiment, the projection mode comprises a fixed mode and a control mode. In the fixed mode, the swinging range is adjusted to project the fixed projection scope. In the control mode, the swinging range is adjusted to the controllable projection scope. 
         [0023]    The present invention further discloses a control method of a projection device.  FIG. 3  is a flowchart of a control method of a projection device according to an embodiment of the present invention. Firstly, the method begins at step  302 , the projection device  110  enters at least one projection mode. Next, the method proceeds to step  304 , the motion detection module  12  detects at least one motion trace of the projection device  110 . Then, the method proceeds to step  306 , the controller  14  adjusts at least one swing angle of the scan unit  112  according to the motion trace to adjust the projection scope that the projection device  110  projects on a projection surface. The projection mode comprises a control mode and a fixed mode. If the projection device  110  enters a control mode in step  302 , then the controller  14  adjusts at least one swing angle of the scan unit  112  according to the motion trace to make the size of the projection scope of the projection device  110  on the projection surface to be changed in step  306 . If the projection device  110  enters a fixed mode in step  302 , then the controller  14  adjusts at least one swing angle of the scan unit  112  according to the motion trace to make the size of the projection scope of the projection device  110  on the projection surface to be fixed in step  306 . 
         [0024]    For example, suppose the projection device  110  enters the control mode in step  302 . In an embodiment, if the motion trace of the projection device  110  detected by the motion detection module  12  is a first motion magnitude of an upward motion, then the controller  14  increases the swing angle at which the scan unit  112  swings up and down to increase the distance between the top boundary and the bottom boundary of the projection scope on the projection surface. In contrast, if the motion trace of the projection device  110  detected by the motion detection module  12  is a first motion magnitude of a downward motion, then the controller  14  reduces the swing angle at which the scan unit  112  swings up and down to reduce the distance between the top boundary and the bottom boundary of the projection scope on the projection surface. Similarly, the motion detection module  12  may also detect the motion trace of the projection device  110  in another direction to adjust the boundary of the projection scope in another direction. If the motion trace of the projection device  110  detected by the motion detection module  12  is a second motion magnitude of a rightward motion, then the controller  14  increases the swing angle at which the scan unit  112  swings left and right to increase the distance between the left boundary and the right boundary of the projection scope on the projection surface. In contrast, if the motion trace of the projection device  110  detected by the motion detection module  12  is a second motion magnitude of a leftward motion, then the controller  14  reduces the swing angle at which the scan unit  112  swings left and right to reduce the distance between the left boundary and the right boundary of the projection scope on the projection surface. 
         [0025]    The above embodiments are exemplary and explanatory only. The present invention does not specify that the controller has to correspondingly adjust the swing direction of the scan unit according to the motion direction of the motion trace. One skilled in the art may modify the control method according to practical use. In another example, the motion detection module  12  can only detect the motion magnitude of an upward or a downward motion of the projection device  110  and make the controller  14  increase or reduce both of the swing angle at which the scan unit  112  swings up and down and the swing angle at which the scan unit  112  swings left and right to increase or reduce the distance between the top boundary and the bottom boundary of the projection scope and the distance between the left boundary and the right boundary of the projection scope, such that the projection scope on the projection surface is enlarged or narrowed. 
         [0026]    In the present embodiment, the controller  14  can further determines the adjustment amount of increasing or reducing the corresponding swing angle of the scan unit  112  according to the motion magnitude of the detected motion trace(s). 
         [0027]    On the other hand, suppose the projection device  110  enters the fixed mode in step  302 . Then, in step  306 , the controller  14  adjusts at least one swing angle of the scan unit  112  according to the detected motion trace(s), and reverses the changed projection scope of the projection range caused by the rotation or displacement of the projection device  100  to the original projection scope, such that the projection scope on the projection surface remains fixed. Details of the method for reversing the changed projection scope caused by the rotation or displacement of the projection device  100  to the original projection scope are disclosed below with exemplifications. 
         [0028]    Please refer to both  FIG. 4  and  FIG. 5 .  FIG. 4  is a schematic diagram of a projection device at an initial position.  FIG. 5  is a schematic diagram of the inclined projection device of  FIG. 4 . Suppose the projection device  110  enters the fixed mode, and the scan unit  112  of  FIG. 4  swings up and down at a swing angle  2 α 1  and forms a projection scope M 1  on a projection surface A 1  at the initial position.  FIG. 5  illustrates the situation when the projection device  100  of  FIG. 4  is rotated upward for an angle dθ. 
         [0029]    Meanwhile, the top surface of the projection device  100  and the xy plane forms an angle dθ, i.e. the angle dθ between the axial line L 1  of the projection device  100  and the z-axis, such that the projection scope on the projection surface A 1  will be enlarged to a projection scope M 2 . After the first rotation angle dθ of an upward motion was detected by the angle detection unit  122 , the controller  14  reduces the first swing angle at which the scan unit  112  swings up and down to an angle  2 α 2  according to the first rotation angle dθ so as to reduce the distance between the top boundary and the bottom boundary of the projection scope to form a projection scope M 3 , such that the projection scope on the projection surface A 1  remains fixed. That is, the projection range M 1  is equivalent to the projection range M 3 . Similarly, after the second rotation angle of a rightward motion was detected by the angle detection unit  122 , the controller  14  reduces the second swing angle at which the scan unit  112  swings left and right according to the second rotation angle so as to reduce the distance between the left boundary and the right boundary of the projection scope, such that the projection scope on the projection surface A 1  remains fixed. Similarly, the controller  14  may also adjust the swing angle at which the scan unit  112  swings in a corresponding direction according to the detected downward or leftward motion, and the detailed descriptions thereof will be omitted herein. 
         [0030]    Another exemplification is disclosed below.  FIG. 6  is a schematic diagram before and after the projection device  100  is displaced. Suppose the scan unit  112  of the projection device  100  of  FIG. 6  swings up and down at a swing angle of  2 α 1 , and the distance between the projection device  100  and the projection surface A 1  is x 1 . As shown in  FIG. 6 , after the projection device  100  was displaced for a distance dx, the distance between the projection device  100  and the projection surface A 1  becomes x 1 +dx, and the projection scope on the projection surface A 1  will be enlarged. After the motion detection unit  124  detected that the projection device  100  was displaced for a displacement dx in the third direction (such as in the x-axis direction), the controller  14  adjusts the first swing angle at which the scan unit  112  swings up and down to an angle  2 α 3 , and the second swing angle at which the scan unit  112  swings left and right according to the displacement dx in the third direction so as to reduce the distance between the top boundary and the bottom boundary and the distance between the left boundary and the right boundary of the projection range, such that the projection scope on the projection surface after the projection device  100  was displaced is equivalent to the original projection scope, and therefore the projection scope on the projection surface remains fixed. The above embodiments are exemplary and explanatory only, not for limiting the scope of the present invention. For example, in the embodiments of the present invention, the swinging range of the scan unit  112  can be adjusted to enlarge or narrow the projection scope according to the first rotation angle, the second rotation angle and the displacement in the third direction. 
         [0031]    According to a projection device and control method thereof disclosed in above embodiments of the present invention, the projection scope is adjusted according to the detected first and second rotation angles of the projection device. In an embodiment, the projection scope can be enlarged or narrowed. In another embodiment, the projection scope can be adjusted according to the displacement in the third direction. Furthermore, in yet another embodiment, the projection scope can be adjusted according to the first rotation angle, the second rotation angle and the displacement in the third direction. In some embodiments, it is very convenient that the user can adjust the size or boundary of the projection scope simply by rotating or waving the projection device. In some other embodiments, even if the projection device is displaced or rotated, the original projection scope still can be maintained, and such design is particularly suitable for applications when a fixed projection scope on the projection surface is desired by the user. 
         [0032]    While the invention has been described by way of example and in terms of the preferred embodiment (s), it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.