Patent Publication Number: US-2018046326-A1

Title: Optical film and user input system

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an optical film and a user input system, and more particularly to an optical film and a user input system that a user can input with an optical reading device. 
     2. Description of the Prior Art 
     A user input system disposes the coding pattern including the addressing information on the substrate, and a user may use an appropriate reading device to decode the addressing information in the coding pattern, so as to record the moving trace of the reading device on the substrate surface. In general, the reading device has a pen structure, so that the user may interact with an electronic device with the used writing manner. The coding pattern of prior-art is mostly disposed on the substrate surface convexly, and therefore, the repeated writing of the reading device may easily cause the coding pattern damaged. 
     Thus, the most important goal for now is to provide a coding pattern that has a better durability. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to provide an optical film and a user input system, which remove partial reflecting layer to form a coding pattern. Therefore, the coding pattern may not be easily damaged by the repeated writing of the optical reading device, so as to improve the durability of the optical film. 
     An optical film of one embodiment of the present invention includes a substrate and a reflecting layer. The substrate has a sensing surface and an opposite back surface. The reflecting layer is disposed on the sensing surface or the back surface of the substrate to reflect a sensing light and includes a coding pattern, wherein the coding pattern is formed by damaging a structure of the reflecting layer, and the coding pattern includes a coding information. 
     A user input system of another embodiment of the present invention includes an optical film and an optical reading device. The optical film includes a substrate and a reflecting layer. The substrate has a sensing surface and an opposite back surface. The reflecting layer is disposed on the sensing surface or the back surface of the substrate to reflect a sensing light and includes a coding pattern, wherein the coding pattern is formed by damaging a structure of the reflecting layer, and the coding pattern includes a coding information. The optical reading device has a contact end to abut against a side of the sensing surface of the optical film. The optical reading device includes a light emitting unit, an image sensor, a processing unit and a communication interface. The light emitting unit is used to produce the sensing light to irradiate the optical film. The image sensor is used to sense the sensing light reflected by the coding pattern and output a sensing image. The processing unit is electrically connected to the image sensor to analyze the sensing image to obtain the coding information of the coding pattern. The communication interface is electrically connected to the processing unit to transmit the coding information to an external electronic device. 
     The objective, technologies, features and advantages of the present invention will become apparent from the following description in conjunction with the accompanying drawings wherein certain embodiments of the present invention are set forth by way of illustration and example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view, showing an optical film of one embodiment of the present invention. 
         FIG. 2  is a schematic view, showing an optical film of another embodiment of the present invention. 
         FIG. 3  is a schematic view, showing a user input system of one embodiment of the present invention. 
         FIG. 4  is a schematic view, showing an optical reading device of the user input system of one embodiment of the present invention. 
         FIG. 5  is a schematic view, showing the configuration of a coding pattern. 
         FIG. 6  is a schematic view, showing the configuration of another coding pattern. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Various embodiments of the present invention will be described in detail below and illustrated in conjunction with the accompanying drawings. In addition to these detailed descriptions, the present invention can be widely implemented in other embodiments, and apparent alternations, modifications and equivalent changes of any mentioned embodiments are all included within the scope of the present invention and based on the scope of the Claims. In the descriptions of the specification, in order to make readers have a more complete understanding about the present invention, many specific details are provided; however, the present invention may be implemented without parts of or all the specific details. In addition, the well-known steps or elements are not described in detail, in order to avoid unnecessary limitations to the present invention. Same or similar elements in Figures will be indicated by same or similar reference numbers. It is noted that the Figures are schematic and may not represent the actual size or number of the elements. For clearness of the Figures, some details may not be fully depicted. 
     Referring to  FIG. 1 , an optical film  10  of one embodiment of the present invention includes a substrate  11  and a reflecting layer  12 . The substrate  10  has a sensing surface  111  and an opposite back surface  112 . In one embodiment, a material of the substrate  11  may be polyethylene terephthalate (PET), Polycarbonate (PC), Polymethylmethacrylate (PMMA), Polyimide (PI), cellulose triacetate (TAC), cyclic olefin polymer (COP) or a PC-PMMA composite film. 
     The reflecting layer  12  is disposed on the sensing surface  111  of the substrate  11  to reflect a sensing light L 1 , which is not a limitation, and the reflecting layer  12  may be disposed on the back surface  112  of the substrate  11  as well. In one embodiment, the sensing light L 1  may be the invisible light, such as the infrared or ultraviolet light. The reflecting layer  12  includes a coding pattern  12   a . For example, the coding pattern  12   a  may be multiple pattern units, and each pattern unit may be a line, a circle, an ellipse, a polygon or a combination thereof. Preferably, a length of a long axis of each pattern unit is different from that of a short axis of each pattern unit, such that the azimuth difference of the pattern units may be determined, such as the rotation angle. It may be understood that the coding pattern  12   a  includes a coding information. For example, the coding information may be at least one of the addressing information, text information, image information, control instruction and anti-counterfeiting information. 
     In one embodiment, the coding pattern  12   a  is formed by damaging a structure of the reflecting layer  12 . For example, the reflecting layer  12  may be formed by using the coating or blooming technology to totally cover the sensing surface  111  of the substrate  11  with a film material structure that may produce reflection for the sensing light of a particular wavelength. Then, the required coding pattern  12   a  may be formed by using the dry etching, wet etching, or laser engraving technology to remove the reflecting layer  12  according to a particular pattern. In one embodiment, the reflecting layer  12  may be a diffractive optical structure, a structure of multiple layers of films having different refractive indexes or a liquid crystal material. It may be understood that the reflecting layer  12  corresponding to the position of the coding pattern may not be necessary to be completely removed. For example, the reflecting layer  12  may be a structure of multiple layers of films having different refractive indexes. The reflecting optical property of the reflecting layer  12  may be damaged by using the etching process or laser engraving process to remove a specific number of the layers of the films. In one embodiment, the substrate  11  and the reflecting layer  12  allow the visible light L 2  to transmit, so that the optical film  10  of the present invention may be applied to a display device, i.e., the image of the visible light displayed by the display device may transmit through the optical film  10  of the present invention. 
     According to the above structure, the pressure that the optical reading device applies to the optical film  10  of the present invention is mostly fallen on the reflecting layer  12  of a continuous structure, and therefore, the depressed coding pattern  12   a  may not be easily worn by the repeated writing of the optical reading device. 
     Referring to  FIG. 2 , the optical film  10  of one embodiment of the present invention further includes a scattering layer  13  that is disposed between the substrate  11  and the reflecting layer  12 . The scattering layer  13  may let the reflecting layer  12  to diffusively reflect the sensing light L 1 , i.e., softening or homogenizing the reflecting intensity of the sensing light L 1 . In one embodiment, the scattering layer  13  may comprise a polymer and a plurality of scattering particles dispersed in the polymer. It may be understood that the refractive index of the scattering particles is different from the refractive index of the polymer. Or, the scattering layer  13  may be the roughed sensing surface  111  or the roughed back surface  112  of the substrate  11 . In one embodiment, a surface roughness of the scattering layer  13  is more than 25 nm. 
     Referring to  FIG. 2  again, in one embodiment, the optical film  10  further includes a coating layer  14  that covers the reflecting layer  12  and is filled in the coding pattern  12   a . It may be understood that the coding pattern  12   a  filled with the coating layer  14  may further avoid the wear of the coding pattern  12   a . In one embodiment, the refractive index of the coating layer  14  may be the same as or different from the refractive index of the substrate  11 . Preferably, the coating layer  14  has at least one property of hard coating, anti-glare, anti-reflection, anti-fingerprint, hydrophobic, and anti-static. 
     In one embodiment, the optical film  10  of the present invention further includes an adhesive layer  15  that is disposed on the back surface  112  of the substrate  11 . Thus, the optical film  10  of the present invention may be attached to an appropriate operating surface, such as the display surface of the display device or a whiteboard. In one embodiment, the adhesive layer  15  has a high transmittance, and for example, the transmittance of the adhesive layer  15  is more than 70%. In one embodiment, the adhesive layer  15  may include a light absorption material that may absorb the light of a particular wavelength, such as the dye or other light absorption agent, so as to meet the requirement of the practical application. For example, the blue dye may be added to change the basic color of the film material. 
     Referring to  FIG. 3  and  FIG. 4 , a user input system of one embodiment of the present invention includes an optical film  10  and an optical reading device  20 . The detailed structure of the optical film  10  is as described above, and omitted here. The optical reading device  20  has a contact end  21  that is used to abut against a side of the sensing surface  111  of the optical film  10 , such that a user may interact with an electronic device with the used writing actions. The optical reading device  20  includes a light emitting unit  201 , an image sensor  202 , a processing unit  203  and a communication interface  204 . 
     The light emitting unit  201  is used to produce the sensing light L 1  to irradiate the optical film  10 . For example, the light emitting unit  201  may be a light-emitting diode that emits the infrared or ultraviolet light, and preferably, the light emitting unit  201  is a light-emitting diode that emits the infrared light. The image sensor  202  is used to sense the sensing light L 1  from the coding pattern and output a sensing image. For example, the image sensor  202  includes a lens and a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS) sensor. The lens may be made of poly methyl methacrylate (PMMA), and may be an optical element that is usually injection-molded. The PMMA has a property of anti-scratch, and has a transmittance of about 90% for the light of the wavelength of 810 nm. A size of the CCD or CMOS sensor may be 128×128 pixels, and preferably, the size of the CCD or CMOS sensor may be 140×140 pixels, so as to have a better manufacturing tolerance. 
     The processing unit  203  is electrically connected to the image sensor  202 . The processing unit  203  may analyze the sensing image to obtain the coding information contained in the coding pattern, such as the addressing information, text information, image information, control instruction or anti-counterfeiting information, etc. The communication interface  204  is electrically connected to the processing unit  203 . The communication interface  204  may transmit the coding information, such as the addressing information, text information, image information, control instruction or anti-counterfeiting information, etc., that is obtained by the processing unit  203  to an external electronic device  30 . For example, the communication interface  204  may be a wire communication interface or a wireless communication interface. Preferably, the communication interface  204  may be a wireless communication interface, so that a disturbance of the wire may be avoided when the user is at the writing operation. For example, the wireless communication interface may be the Bluetooth, wireless local area network (WLAN), ZigBee communication, wireless USB or mobile communication network. 
     In one embodiment, the user input system of the present invention further includes a display device  31  that is disposed at a side of the back surface of the optical film  10 , i.e., the optical film  10  is disposed on a display surface of the display device  31 . The display device  31  is electrically connected to the external electronic device  30 . Based on this architecture, the external electronic device  30  may present the coding information received from the optical reading device  20  through the display device  31  in real-time. For example, the user may sign or paint on the optical film  10  of the present invention with the optical reading device  20 , and the external electronic device  30  may display the sign or paint of the user through the display device  31  in real-time. Or, the user may click on a specific area of the optical film  10  with the optical reading device  20  to decode the corresponding control instruction, so as to execute the operation, such as clicking, circle-selecting, paging down or scrolling the page, etc. 
     Referring to  FIG. 5 , in one embodiment, the coding pattern includes virtual grid lines  51  and multiple pattern units  52 . The virtual grid lines  51  are not really disposed on the optical film  10 , and therefore, are depicted in dotted lines. In one embodiment, the virtual grid lines  51  are perpendicularly intersected with each other, and multiple intersections are formed. The coding information, such as the addressing information, text information, image information, control instruction or anti-counterfeiting information, etc., is encoded according to the positions of the pattern units  52  relative to the intersections of the virtual grid lines  51 . In the embodiment shown in  FIG. 5 , the pattern unit  52  comprises a line segment and circles, and the pattern unit  52  is disposed at the intersection of the virtual grid lines  51  with the center thereof. As shown in  FIG. 5 , the pattern units  52  that are horizontal, vertical, tilted 45 degrees to the right and tilted 45 degrees to the left respectively may represent four different coding values respectively. Thus, the coding information may be encoded with the pattern units  52 . It may be understood that multiple pattern units  52  may form a set to encode more coding information. 
     Referring to  FIG. 6 , in one embodiment, the pattern unit  52  may be disposed at the intersection of the virtual grid lines  51  with one endpoint thereof as well. As shown in  FIG. 6 , the presented pattern units  52  of 0 degrees, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees and 315 degrees may represent eight different coding values respectively. The detailed encoding method is familiar to those skilled in the art and is not the main subject matter of the present invention, and therefore, the descriptions thereof are omitted here. It should be noted that in addition to the above encoding method, the coding information may be implemented with other appropriate encoding method as well. 
     To sum up the foregoing descriptions, the optical film and the user input system of the present invention remove partial reflecting layer to form the coding pattern having a depressed structure. Therefore, the coding pattern of the optical film of the present invention may not be easily damaged by the repeated writing of the optical reading device, so as to improve the durability of the optical film. Also, a purpose of a reflecting signal having a high contrast may be achieved, and the reading sensitivity of the user input system may be improved significantly.