Abstract:
A projection device is provide, including a projection module having at least an optical lens, the projection module receiving data and converting display data into an optical image to be projected on a display area by the optical lens. The projection device can be positioned substantially close to the display area. This allows the projection device to directly project the optical image on the display area without having to adjust a projection angle, and also makes the projected image free of obstruction from movement of a user. Therefore, data display and projection operation can be conveniently and efficiently implemented.

Description:
FIELD OF THE INVENTION 
   The present invention relates to image projecting technology, and more particularly, to a projection device for projecting an image on an intended display area. 
   BACKGROUND OF THE INVENTION 
   Conventional projectors such as over head projector, slide projector, CRT (cathode-ray tube) projector, LCD (liquid crystal display) panel, DLP (digital light processing) projector, and so on are used to project text and/or images on a display area or panel for allowing more people to simultaneously view the text and/or images. An advanced projector can be connected to a notebook computer or a desktop computer, allowing data processed from the computer to be projected by the projectors without having to print out data on papers and thus free of concern that data may be unclearly shown on the papers and degrade quality of projection. 
   The foregoing projector can further be connected to a digitizing tablet which is a digital input board with a touch-sensitive surface on which a user may write with a touch pen. Moreover, the digitizing tablet can be connected to a computer by which text written on the digitizing tablet is converted via recognition software into readable data for the computer or user, or printed out by a printer connected to the computer. This also allows the projector to project an image displayed on a screen of the computer onto the digitizing tablet, whereby the user can use the touch pen as a pointing device to operate application programs executed by the computer. 
     FIG. 1  illustrates a connection structure of a digitizing tablet and a computer, which includes a digitizing tablet  10 , a computer  20 , and a projector  30 . 
   The digitizing tablet  10  allows a user to write thereon with a touch pen  12  and accordingly generates associated pixel coordinate data to be sent to the computer  20  via a connection interface  11  such as a wired RS-232 interface or a wireless IrDA (infrared data association) interface. The computer  20  converts the pixel coordinate data into data readable for the computer or user, or prints out data via a printer (not shown) connected thereto. 
   The computer  207  such as a desktop computer or a notebook computer, is connected to the digitizing tablet  10  via the connection interface  11 , for receiving and converting the pixel coordinate data from the digitizing tablet  10  into associated images or operating commands. 
   The projector  30  converts an image displayed by the computer  20  into an optical image and projects the optical image on the digitizing tablet  10 . Thereby, the user may use the touch pen  12  as a pointing pen to select various operational functions displayed on the digitizing tablet  10 . 
   However, in practice, the connection structure of the projector, digitizing tablet and computer renders the following disadvantages. It requires external cables for connecting the computer  20  and projector  30 , besides, if the connection interface  11  is a wired RS-232 interface, more cables are used to connect the computer  20  and digitizing tablet  10 . The use of cables undesirably makes the connection structure relatively messy in appearance. Furthermore, the user needs to adjust a projection angle of the projector  30  to align the projected image onto a projection screen for each time of operation, making the projection operation fairly time-ineffective to implement. In addition, movement of the user e.g. a speaker may easily interfere with the projected image on the projection screen, which would adversely affect attention of the audience or viewers and degrade quality of the image display. 
   SUMMARY OF THE INVENTION 
   An objective of the present invention is to provide a projection device by which projected data would not be affected from movement of a user. 
   Another objective of the invention is to provide a projection device by which the user does not need to adjust a projection angle of the projection device. 
   In order to achieve the foregoing and other objectives, the present invention proposes a projection device, including a projection module having at least an optical lens, the projection module receiving and converting display data into an optical image to be projected on a display area by the optical lens. 
   In another embodiment, the projection device further includes an optical reflector which is used to reflect the optical image projected from the optical lens on the display area. 
   In a further embodiment, the projection device further includes a computer for processing and converting data into display data, wherein the computer is connected to the projection module and sends the display data to the projection module. 
   In a further embodiment, the computer further includes at least one communication interface connected to a peripheral device such as a scanner, a digital camera, a slide projector, or a device capable of outputting display data, so as to allow the projection device with the computer to receive display data from he peripheral device and convert the display data into an optical image for display. 
   The projection device according to the invention provides significant benefits, which can be placed closer to a display area and connected to an electronic device for processing or storing data of sounds or images. In particular, this projection device is positioned to allow a projected image to be free of obstruction from movement of a user, and is connected to a computer for allowing display of the projected image through the use of the projection device and computer without having to adjust a projection angle via the user. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention can be more fully understood by reading the following detailed description of the preferred embodiments, with reference made to the accompanying drawings, wherein: 
       FIG. 1  (PRIOR ART) is a schematic diagram showing a conventional connection structure of a projection device; 
       FIGS. 2A and 2B  are respectively a front view and a side view of a projection device according to a first preferred embodiment of the invention; 
       FIGS. 3A and 3B  are respectively a front view and a side view of the projection device according to a second preferred embodiment of the invention; 
       FIGS. 4A and 4B  are respectively a front view and a side view of the projection device according to a third preferred embodiment of the invention; 
       FIG. 5  is a schematic diagram of the projection device according to a fourth preferred embodiment of the invention; 
       FIG. 6  is a schematic diagram of the projection device according to a fifth preferred embodiment of the invention; and 
       FIG. 7  is a schematic diagram of the projection device according to a sixth preferred embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Preferred embodiments of a projection device proposed in the present invention are described in detail with reference to  FIGS. 2-7 . 
   First Preferred Embodiment 
     FIGS. 2A and 2B  illustrate front and side views of a projection device according to a first preferred embodiment of the invention. As shown in the drawings, this projection device having a projection module  120  is installed on a bottom side of a display area  1  for displaying an optical image. The projection device comprises at least one projection module  120 . It should be understood that the projection device may alternatively be mounted on a left, right or top side of the display area  1  depending on practical requirements. The display area  1  can be a wall, a whiteboard, a digitizing tablet, or any other suitable surface for image display. 
   In this embodiment, the projection module  120  has a communication interface  121 , an optical lens  131  (having at least a convex lens) with an optic axis directed toward a same direction as the display area  1 , and an optical reflector  132  formed on the optic axis of the optical lens  131 . The projection module  120  can be connected via the communication interface  121  (e.g. USB, RS-232, PS/2, etc.) to an external data processing device (not shown) capable of outputting display data such as a computer, scanner, digital camera and so on. This allows the projection module  120  to convert the display data (e.g. a VGA image) from the data processing device into an optical image which is then projected from the optical lens  131  along a predetermined direction and reflected on the display area  1  by the optical reflector  132 . 
   In practice, if a user intends to display data on the display area  1 , he or she only needs to operate the projection module  120  to download and convert the VGA image into an optical image that can then be projected and reflected on the display area  1 . 
   In the use of the projection device according to the invention, the user may optionally install the projection device significantly closer to the display area  1  than is feasible with the prior art or on any side of the display area  1 . Since the display area  1  and the projection device are closely arranged with considerably small or even no space therebetween, movement of users or viewer would not obstruct the projected image. 
   Second Preferred Embodiment 
     FIGS. 3A and 3B  illustrate front and side views of the projection device according to a second preferred embodiment of the invention. As shown in the drawings, this projection device is connected to a digitizing tablet  100 , and at least includes a computer  110  and a projection module  120 . 
   The digitizing tablet  100  has a connection interface  101 , such as a standard wired RS-232 interface, for connecting the digitizing tablet  100  to the computer  110 . characteristic feature of the invention is to use internal circuits for the connection between the digitizing tablet  100  and the computer  110 , thereby not having to use inconvenient external cables. 
   The computer  110  is a data processing module such as a RISC (reduced instruction set computing) unit which can execute various data processing functions, for example to process data to be displayed on the digitizing tablet  100 . Furthermore, the computer  110  can be further formed with a data storage unit  111  (such as DVD-ROM drive, CD-ROM drive, hard disk drive, floppy disk drive, etc.) and a communication interface  112  (such as USB. RS-232, PS/2, etc.). The data storage unit  111  is used to store data to be displayed by the computer  100  and data downloaded from the digitizing tablet  100 . The communication interface  112  is used to connect the computer  110  to an external peripheral device or another computer (not shown), for allowing the user to store data in the peripheral device or another computer. 
   In this embodiment, the projection module  120  has an optical lens  131  and an optical reflector  132 , and is connected to the computer  110 . This allows the projection module  120  to convert display data (such as a VGA image) from the computer  110  into an optical image which is then projected from the optical lens  131  along a predetermined direction and reflected on the digitizing tablet  100  by the optical reflector  132 . 
   The computer  110  further includes a TV tuner interface built on an expansion card such as a TV card for providing a channel selection function, and thus the projection module  120  can project an input TV signal onto the digitizing tablet  100  or the display area  1 . 
   Third Preferred Embodiment 
     FIGS. 4A and 4B  illustrate front and side views of the projection device according to a third preferred embodiment of the invention. This projection device is connected to a digitizing tablet  200 , and at least includes a computer  210  and a projection module  220 . 
   Similarly to the above second preferred embodiment, the digitizing tablet  200  may have a connection interface  201  for connecting the digitizing tablet  200  to the computer  210 , and may further include a data storage unit  211  (such as DVD-ROM drive, CD-ROM drive, hard disk drive, floppy disk drive, etc.) and a communication interface  212  (such as USB, RS-232, PS/2, etc.). 
   A characteristic feature of this embodiment is that the projection module  220  has an optical lens  231  only but not with an optical reflector, wherein an optic axis of the optical lens  231  is directed at a predetermined angle toward the digitizing tablet  200 , so as to allow an optical image to be directly projected by the optical lens  231  on the digitizing tablet  200 . 
   In addition, beside the digitizing tablet, the projection device according to the second and third embodiments is also operable together with a common projection screen, such as a wall, whiteboard, curtain screen, etc. And, the projection device can be also applied to a home theater, presentation panel, indoor or outdoor billboard, or aircraft in-flight system. 
   Fourth Preferred Embodiment 
     FIG. 5  illustrates the projection device according to a fourth preferred embodiment of the invention. In this embodiment, a plurality of projection devices ( 41 ,  51 ,  61 , . . . ) are each mounted on a side of a corresponding projection screen ( 40 ,  50 ,  60 , . . . ). A plurality of communication interfaces ( 410 ,  510 ,  610 , . . . ) formed with the projection devices ( 41 ,  51 ,  61  . . . ) are connected to a server  300  via a network transmission system  400  (such as intranet). The server  300  has a data processing module  301  and a network communication interface  302 . The network communication interface  302  is used to integrate and manage data flows for the projection devices ( 41 ,  5161 , . . . ). The data processing module  301  is used to control display processing functions of the projection devices ( 41 ,  51 ,  61 , . . . ), for example to provide respective displays on multiple windows, a single display on all multiple windows, or variable displayed on different combinations of multiple windows, etc. 
   The above arrangement thereby allows a display with larger area such as a blackboard, or multiple data displays such as financial or stock market displays. Further, the projection devices ( 41 ,  51 ,  61 , . . . ) may individually or simultaneously be connected to a network (such as Internet) via a hub for reading and displaying data. 
   Fifth Preferred Embodiment 
     FIG. 6  illustrates the projection device according to a fifth preferred embodiment of the invention. This projection device  61  is mounted on a side of a projection screen  60  (such as a digitizing tablet, wall, panel, etc.) and connected to a scanning device  70  via a communication interface  610  thereof. This allows data intended for display to be scanned by the scanning device  70  and inputted via the communication interface  610  to a computer  611  installed with the projection device  61  where the data are processed to be projected on the projection screen  60 . The computer  611  may also include a set of control software with a scanning function to process the data from the scanning device  70  for being stored in the computer  611  or for being directly displayed on the projection screen  60 . 
   Moreover, the projection device  61  can be connected via the communication interface  610  to a network communication system  71  such as Internet, and operate with an electronic device having a headphone and speaker to perform web-phone communication. 
   Sixth Preferred Embodiment 
     FIG. 7  illustrates the projection device according to a sixth preferred embodiment of the invention. In this embodiment, four of the projection devices ( 81 ,  82 ,  83 ,  84 ) are installed on a frame  801 , each of which is connected to a computer  80  that is used to control a display processing function of the projection devices ( 81 ,  82 ,  83 ,  84 ) via a data transmission wire  800 . The computer  80  may be further connected to an external keyboard (not shown) by which a user can input a control signal to control the display processing function, for example to provide respective displays on multiple windows, a single display on all multiple windows, or variable displayed on different combinations of multiple windows, etc. Moreover, each of the projection devices ( 81 ,  82 ,  83 ,  84 ) may be formed with a pair of rollers (not shown) to enable the computer  80  to position the projection devices ( 81 ,  82 ,  83 ,  84 ) respectively with respect to the frame  801 . In this manner, display areas ( 92 ,  92 ,  93 ,  94 ) respective for the projection devices ( 81 ,  82 ,  83 ,  84 ) can be flexibly modulated to achieve desirable display effect, each of which can be a wall, ceiling, the ground, or any other suitable surface. 
   The number of projection device mounted on the frame is not limited to four illustrated in  FIG. 7  but can be flexibly adjusted according to practical requirements. The projection device according to the invention may also mounted on a rear side of a light-permeable display panel (not shown), such as a curtain screen, glass board, or plastic board, to thereby serve as a rear projection device. 
   Moreover, the projection device according to the invention uses an image processor IC (integrated circuit) to integrate signals from processing circuits such as RGB (red-green-blue) generator circuits, image decoder circuits, analog-to-digital converter, phase lock loops (PLL), and frame registers. Then, the integrated signals are outputted via a control IC to an optical lens of the projection device, wherein the output signals from the control IC are adjusted by an OSD controller. 
   A characteristic feature of the projection device according to the invention is to allow a user to perform short-distance image projection. For preventing image deformation by short-distance projection, the projection device needs to implement the following procedures, including a real-time geometry process, an advanced image process, a process for brightness, contrast, hue and saturation control (i.e. high quality image output), a process for two-dimensional off-axis projection (keystone correction), and a high quality de-interlacing process. By these procedures and the above associated hardware circuits, the projection device according to the invention can adequately eliminate deformation of projected images due to an inclined projection angle to provide satisfactory projection effect as a normal front- or rear-projection device. 
   Therefore, the projection device according to the invention provides significant benefits, which can be placed closer to a display area and connected to an electronic device for processing or storing data of sounds or images. In particular, this projection device is positioned to allow a projected image to be free of obstruction from movement of a user, and is connected to a computer for allowing display of the projected image through the use of the projection device and computer without having to adjust a projection angle via the user. 
   The invention has been described using exemplary preferred embodiments. However, it is to be understood that the scope of the invention is not limited to the disclosed embodiments. On the contrary, the scope claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.