Patent Publication Number: US-2012032918-A1

Title: Touch screen apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a Continuation-In-Part of pending U.S. patent application Ser. No. 12/240,774, filed Sep., 29, 2008 and entitled “Touch Screen Apparatus”. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a touch screen apparatus, and in particular, to a touch screen apparatus featuring greater accuracy and more precise positioning. 
     2. Description of the Related Art 
       FIG. 1  is a schematic view depicting a conventional capacitive-type touch screen apparatus. In the conventional capacitive-type touch screen apparatus, the power  11  is inputted through four corners or four sides of the touch screen, and the electrode provides voltages to generate a uniform electric field  12 . When a finger  13  touches the touch screen, an electric current, evoked on the four sides of the touch screen, passes through the equivalent bioimpedance Z to the ground. The distances from a contact point to the four sides of the touch screen are different, thus the current intensity on each side is accordingly different. Therefore, a controller  14  is able to calculate the position of the contact point according to the current intensity on the four sides. 
     However, the conventional capacitive-type touch screen apparatus is operated by finger contact. Because the human finger may require a large contact area when touching the touch screen, the contact position is inaccurate and lacks precision, and the display image is also blocked by the finger. Additionally, the equivalent impedance and the equivalent capacitance vary from person to person, and thus the current intensity also varies, resulting in contact position detection errors. 
     BRIEF SUMMARY OF THE INVENTION 
     The objective of the invention is to provide a touch screen apparatus featuring a contact position with enhanced accuracy. 
     Accordingly, the invention provides a touch screen apparatus applied to a touch panel comprising an indicating device and a processing module. The indicating device comprises a signal generating module and a conductive touch end, wherein the touch end touches the touch panel, and the signal generating module, electrically connecting with the touch end, generates an electric signal transmitted through the touch end. The processing module electrically connects with the touch panel to detect the electric signal, and calculates a contact position between the touch end and the touch panel according to the electric signal. 
     The touch panel is preferably a capacitive-type touch panel. The electric signal is preferably an alternating signal. The signal generating module is preferably a SN-wave generator. The touch panel is preferably formed by a protecting layer, an insulating layer, a conductive layer and a substrate. 
     According to the touch screen apparatus, the indicating device further comprises a wire, a battery and a holding portion. The wire connects the signal generating module and the touch end. The battery, a dry cell, a lithium cell, a mercuric oxide cell or a solar cell, provides power to the signal generating module. The holding portion, held by an operator, is conductive and electrically connects to the wire or a negative electrode of the battery to form a ground connection through a human body. 
     According to the touch screen apparatus, the touch end is made of elastic material or is a stiff tapered end or a stiff spherical end covered by an elastic member. The elastic member, which is conductive, covers a portion of the touch end or entire touch end. 
     According to the touch screen apparatus, the indicating device further comprises a fastening portion to engage and fix the touch end, wherein the fastening portion is conductive. Additionally, the processing module further comprises a detecting circuit and a controller. The detecting circuit is disposed on four sides or four corners of the control panel to detect the electric signal of the touch panel. The controller electrically connects with the detecting circuit to calculate the contact position between the touch end and the touch panel according the electric signal. The controller is preferably a microcontroller or a computer. 
     To achieve the objective, the invention provides another touch screen apparatus, applied to a touch panel, comprising an indicating device and a processing module. The indicating device comprises a holding portion and a conductive touch end, wherein the holding portion, held by an operator, electrically connects to the touch end to form a ground connection through a human body, and the touch end touches the touch panel. The processing module electrically connects with the touch panel to calculate a contact position between the touch end and the touch panel. 
     The touch end is made of elastic material or is a stiff tapered end or a stiff spherical end covered by an elastic member. The elastic member, which is conductive, covers a portion of the touch end or entire touch end. The indicating device further comprises a fastening portion to engage and fix the touch end, wherein the fastening portion is conductive. 
     The touch panel, a capacitive-type touch panel, is preferably formed by an insulating layer and a conductive layer, and further comprises a protecting layer and a substrate. In the touch screen apparatus, alternating current is inputted through four corners or four sides of the touch panel to form a uniform electric field. Moreover, the processing module further comprises a detecting circuit and a controller. The detecting circuit is disposed on the four sides or the four corners of the control panel to detect changes of the electric field. The controller electrically connects with the detecting circuit to calculate the contact position between the touch end and the touch panel according the changes of the electric field. The controller is preferably a microcontroller or a computer. 
     Additionally, the touch panel is a sonic-type touch panel and a sound signal is distributed on a surface of the touch panel. The processing module detects changes of the sound signal to calculate the contact position between the touch end and the touch panel. The processing module further comprises a controller, a transducer and a reflecting device. The controller, sending and receiving an electric signal, calculates the contact position between the touch end and the touch panel according to the electric signal. The transducer transduces the electric signal to a sound signal or transduces the sound signal to an electric signal. The reflecting device, disposed on a periphery of the touch panel, reflects the sound signal to the transducer. 
     In conclusion, the touch screen apparatus utilizes an indicating device with a signal generating module to transmit an electric signal to the touch panel, such that the processing module is able to calculate the contact position between the indicating device and the touch panel according the detected electric signal of the touch panel, thus improving the accuracy of the contact position when the touch panel is touched by fingers. Furthermore, the indicating device comprises a conductive holding portion to be held by an operator. The holding portion electrically connects to the touch end to form a ground connection through a human body, promoting improved signal integrity. 
     Furthermore, another embodiment of the touch screen apparatus is provided. By connecting the holding portion, held by an operator, to the touch end, the ground connection is achieved when the touch end contacts the touch panel. Thus, the uniform electric field is accordingly changed, such that the contact position between the touch end and the touch panel can be calculated. As a result, inaccuracy and imprecision of an image display by finger contact are all improved. 
     Moreover, another embodiment of the touch screen apparatus is provided. The touch end absorbs sound signals distributed on the surface of the touch panel to descend the potential thereof, such that the contact position between the touch end and the touch panel can be calculated, enhancing the accuracy thereof. 
     A detailed description is given in the following embodiments with reference to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein: 
         FIG. 1  is a schematic view of a conventional capacitive-type touch screen apparatus; 
         FIG. 2  is a schematic view of a preferred embodiment of a touch screen apparatus of the present invention; 
         FIGS. 3A and 3B  are schematic views showing variant touch ends of the touch screen apparatus according to the present invention; 
         FIGS. 4A and 4B  are schematic views showing different grounding modes of the touch screen apparatus according to the present invention; 
         FIG. 5  is a schematic view of a preferred embodiment of a variant touch screen apparatus of the present invention; 
         FIGS. 6A and 6B  are schematic views showing variant touch ends of another touch screen apparatus according to the present invention; 
         FIG. 7  is a schematic view of the touch screen apparatus of the present invention; 
         FIG. 8  is a schematic view of a preferred embodiment of another variant touch screen apparatus of the present invention; and 
         FIG. 9  is a schematic view of a preferred embodiment of another variant touch screen apparatus of the present invention. 
         FIGS. 10 and 11  are schematic diagrams of the touch screen apparatus according to another two embodiments of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to the relative figures, schematic views are shown to provide touch screen apparatuses of preferred embodiments, wherein same elements are referenced the same. 
       FIG. 2  is a schematic view of a preferred embodiment of a touch screen apparatus of the present invention. The touch screen apparatus comprises a touch panel  21 , an indicating device  22  and a processing module  23 . The indicating module  22  comprises a signal generating module  222  and a conductive touch end  221 . The touch end  221  touches the touch panel  21 , and the signal generating module  222 , generating an electric signal, electrically connects with the touch end and transmits the electric signal through the touch end  221 . The processing module  23  electrically connects with the touch panel  21 . When the touch end  221  contacts the touch panel  21 , the processing module  23  detects an electric signal of the touch panel  21  and calculates a contact position between the touch end  221  and the touch panel  22  according to the electric signal. 
     The touch panel is preferably a capacitive-type touch panel. The electric signal is preferably an alternating signal. The signal generating module is preferably a SIN-wave generator. The touch end is preferably made of elastic material. The processing module further comprises a detecting circuit disposed on four sides or four corners of the touch panel for detecting the electric signal, such that the processing module is able to calculate the contact position between the touch end and the touch panel according to the signal intensity on the four sides or the four corners of the touch panel. 
       FIG. 3A  is schematic views showing a variant touch end of the touch screen apparatus. The touch screen apparatus comprises a touch panel  21 , an indicating device  31  and a processing module  23 . The indicating device  31  comprises a signal generating module  222 , a touch end  311 , an elastic member  312  and a fastening portion  313 . The embodiment differs from that of  FIG. 2  in that the touch end  311  is surrounded by the elastic member  312 . The elastic member  312 , which is conductive, covers a portion of the touch end  311  or the entire touch end  311 . Additionally, the touch end  311  is a stiff tapered end. The elastic member  312  is structured to cover the stiff tapered end, such that when the indicating device  31  touches the touch panel  21 , the accuracy and the convenience of data input are not affected by the softness and the over deformation of the touch end  311 . Further, the elastic member  312  provides protection for the touch panel  21  to avoid scratches thereon. Additionally, the fastening portion  313 , engaging with the touch end  311 , stabilizes and fixes the touch end  311  when the indicating device  31  contacts the touch panel  21 . The fastening portion  313  can be conductive according to requirement. Referring to  FIG. 3B , it differs from  FIG. 3A  in that the touch end  321  of the indicating device  32  is a stiff spherical end covered by the elastic member  322 . 
       FIGS. 4A and 4B  are schematic views showing different grounding modes of the touch screen apparatus. As shown in  FIG. 4A , the touch screen apparatus comprises a touch panel, an indicating device  41  and a processing module  23 . The indicating device  41  comprises a signal generating module  222 , a touch end  221 , a holding portion  412  and a wire  411 . The embodiment differs from that of  FIG. 2  in that the indicating device  41  comprises the wire  411 , electrically connecting the signal generating module  222  and the touch end  221 , and the holding portion  412  is to be held by an operator. The holding portion  412 , which is conductive, electrically connects to the wire  411  and connects to the ground through an equivalent bioimpedance Z. 
     Moreover, in  FIG. 4B , the indicating device  42  comprises a battery  421  providing power to the signal generating module  222 . The holding portion  412  connects to a negative electrode of the battery  421 , and then connects to the ground through the equivalent bioimpedance Z. As shown in  FIGS. 4A and 4B , such a structure improves the signal integrity of the electric signal generated by the signal generating module  222 , thus increasing the accuracy and precision of the calculation of the contact position between the touch end  221  and the touch panel  21  by the processing module  23 . The battery is preferably a dry cell, a lithium cell, a mercuric oxide cell or a solar cell. 
       FIG. 5  is a schematic view of a preferred embodiment of a variant touch screen apparatus of the invention. The contact screen apparatus comprises a touch panel  51 , an indicating device  52  and a processing module  53 . A uniform electric field is distributed on a surface of the touch panel  51 . The electric field is preferably formed by inputting alternating current to the four corners or the four sides of the touch panel  51 . The touch panel  51  includes a layer  511  formed on the surface of the touch panel  51 . The layer  511  can be a composite layer including two conductive layers and one insulating layer disposed between these two conductive layers. Alternatively, the layer  511  can also be constituted by one protecting layer, one insulating layer and one conductive layer. The indicating device  52  comprises a holding portion  522 , which is conductive, and a touch end  521 . The touch end  21  touches the touch panel  51 , and the holding portion  522 , held by an operator, electrically connects with the touch end  521 . When the touch end  521  touches the touch panel  51 , the electric current is evoked on the four sides or the four corners of the touch panel  51 . The electric current flows to the holding portion  522  through the touch end  521  of the indicating device  52  and connects to the ground through equivalent bioimpedance Z, successfully making ground connection through a human body. The processing module  53 , electrically connecting with the touch panel  51 , detects the changes of the electric field on the touch panel  51  to calculate the contact position between the touch end  521  and the touch panel  51 . Further, the processing module  53  comprises a detecting circuit disposed on the four sides or four corners of the touch panel  51 . Because the current intensity is inverse to the distance, when the distances from the contact point to the four sides or the four corners of the touch panel  51  are different, the currents detected on the four sides or the four corners of the touch panel  51  are also different. Thus, the contact position can be accordingly calculated. 
     The touch panel is preferably a capacitive-type touch panel, and the touch end is preferably made of an elastic material. 
       FIG. 6A  is schematic view showing variant touch ends of another touch screen apparatus. The touch screen apparatus comprises a touch panel  51 , an indicating device  61  and a processing module  53 . The indicating device  52  comprises a touch end  611 , a holding portion  522 , an elastic member  612  and a fastening portion  613 . The embodiment differs from that of  FIG. 5  in that the touch end  611  is surrounded by the elastic member  612 . The elastic member  612 , which is conductive, covers a portion of the touch end  611  or the entire touch end  611 . Additionally, the touch end  611  is a stiff tapered end. The elastic member  612  is structured to cover the stiff tapered end, such that when the indicating device  61  touches the touch panel  51 , the accuracy and the convenience of data input are not affected by the softness and the over deformation of the touch end  611 . Further, the elastic member  612  provides protection for the touch panel  51  to avoid scratches thereon. Additionally, the fastening portion  613  of the embodiment, engaging with the touch end  611 , stabilizes and fixes the touch end  611  when the indicating device  61  contacts the touch panel  51 . The fastening portion  63  can be conductive according to requirement. Referring to  FIG. 6B , it differs from  FIG. 6A  in that the touch end  621  of the indicating device  62  is a stiff spherical end covered by the elastic member  622 . 
       FIG. 7  is a schematic view of the touch screen apparatus of the invention. In all embodiments described previously, the processing module comprises a detecting circuit  731 , coupled to the touch panel, and a controller  732 , coupled to the detecting circuit  731 , for calculating the contact position between the indicating device  72  and the touch panel. In the described embodiments, the controller  732  is preferably a microcontroller or a computer. The touch panel is formed by a protecting layer  711 , an insulating layer  712 , a conductive layer  713  and a substrate  714 , wherein the positions of the protecting layer  711  and the insulating layer  712  are interchangeable. The touch screen apparatus is applied to a capacitive-type touch panel. 
       FIG. 8  is a schematic view of a preferred embodiment of another variant touch screen apparatus of the invention. The touch screen apparatus comprises a touch panel  81 , an indicating device  82  and a processing module  83 . A sound signal is distributed on a surface of the touch panel  81 . The indicating device  82  comprises a touch end  821  touching the touch panel  81 . The processing module  83 , electrically connecting with the touch panel  81 , detects changes of the sound signal  811  on the touch panel  81  to calculate the contact position between the touch end  821  and the touch panel  81 . 
     The touch panel is preferably a sonic-type touch panel. The touch end is made of an elastic material or is a stiff tapered end or a stiff spherical end covered by an elastic member. The elastic member, which is conductive, covers a portion of the touch end or the entire touch end. The indicating device further comprises a fastening portion to engage and fix the touch end, wherein the fastening portion may be conductive. 
       FIG. 9  is a schematic view of a preferred embodiment of another variant touch screen apparatus of the invention. The embodiment differs from that of  FIG. 8  in that the processing module further comprises a controller  91 , a plurality of transducers  92  and a plurality of reflecting devices  93 . The controller  91 , sending and receiving an electric signal, calculates the contact position between the touch end  821  and the touch panel  81  according to the electric signal. The transducers  92  transduce the electric signal to a sound signal or transduce the sound signal to an electric signal. The reflecting devices  93 , disposed on the four sides of the four corners of the touch panel  81 , reflect the sound signal  811  to the transducers  92 . 
     Please refer to  FIGS. 10 and 11  showing the touch screen apparatus according to further another two embodiments of the present invention. The touch screen apparatus comprises a touch panel  51 , an indicating device  61  and a processing module  53 . The indicating device  52  comprises a touch end  611 , a holding portion  522 , a cover member  612 ′ and a fastening portion  613 , wherein the touch end  611  is surrounded by a cover member  612 ′ covering a portion or entire portion of the touch end. These two embodiments differ from those of  FIGS. 6A and 6B  in that the touch end  611  is made of soft and elastic conductive material such as conductive rubber or conductive foam. The cover member  612 ′ is made of conductive or non-conductive material. The cover member  612 ′ can be made of a material with low friction coefficient or with lubrication such as Nylon, cotton cloth, gunny cloth, linen, man-made fiber fabric, silk cloth, metallic cloth, metal mesh, conductive or non-conductive plastic, PET or other types of plastics, DuPont Vespel, thin Teflon, ITO, SiO 2 , metal coating layer, conductive or non-conductive rubber, conductive or non-conductive organic coating, epoxy coating, paint coating, carbon fiber layer, glass fiber layer, etc. 
     In summary, the touch screen apparatus utilizes a indicating device with a signal generating module to transmit an electric signal to the touch panel so that the processing module is able to calculate the contact position between the indicating device and the touch panel according to the detected electric signal of the touch panel, thus improving the accuracy of the contact position. Furthermore, the indicating device comprises a conductive holding portion to be held by an operator. The holding portion electrically connects to the touch end to form a ground connection through a human body, thereby enhancing the intensity of the signal. 
     Furthermore, another embodiment of the touch screen apparatus is provided. By connecting the holding portion, held by an operator, to the touch end, the ground connection is achieved when the touch end contacts the touch panel. The uniform electric field is accordingly changed, such that the contact position between the touch end and the touch panel can be calculated. As a result, inaccuracy, and imprecision of an image display by finger contact are all improved. 
     Moreover, another embodiment of the touch screen apparatus is provided. The touch end absorbs sound signals distributed on the surface of the touch panel to descend the potential thereof, such that the contact position between the touch end and the touch panel can be calculated, enhancing the accuracy thereof. 
     The touch screen apparatus of the invention can be applied to any portable device, a computer, an electric appliance, a game machine, an automobile electronic device, a gambling machine, a ticket machine, a vending machine or industrial computer products. 
     While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.