Patent Publication Number: US-2013229383-A1

Title: Sensing Structure of a Display

Description:
This application is a divisional application of U.S. application Ser. No. 13/707,838 filed Dec. 7, 2012, which is a divisional application of U.S. application Ser. No. 12/115,918 filed May 6, 2008, which claims priority to Taiwan Patent Application No. 097104533, filed Feb. 5, 2008, the disclosures of which are incorporated herein by reference in their entirety. 
    
    
     CROSS-REFERENCES TO RELATED APPLICATIONS 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a sensing structure; and particularly relates to a sensing structure of a display. 
     2. Descriptions of the Related Art 
     The advancement of electro-optical technologies and the digitalization of image technologies have made displays widespread in every day life. Among these displays, liquid crystal displays (LCDs) are widely used in various communication and electronic products due to their advantages such as high definition, light weight, thin profile, low power consumption, and low radiation. In the display market, LCDs have gradually replaced conventional cathode ray tube (CRT) displays. 
     To enhance the interactivity with the users and the utility of LCDs, some LCDs have touch sensing functions for users to select the desired options by directly touching icons on these displays, or by directly handwriting characters or symbols onto these displays. With the touch sensing function, it is not necessary to reserve some space for the keyboards or other functional buttons in electronic products. Therefore, a larger display panel can be accommodated within electronic products of the same size. 
     As shown in  FIG. 1 , in a conventional display field, a sensing structure  1  comprises a display module  11 , a touch panel  12 , a sensor chip  13 , a flexible printed circuit (FPC)  14 , and a driver chip  16 . The touch panel  12  is attached on the display module  11 . The sensor chip  13  is disposed on the FPC  14  and is electrically connected with the touch panel  12  via conductive lines. The sensor chip  13  is adapted to process the sensing signals generated by the touch panel  12  when touched. 
       FIG. 1  also shows the display module  11  which comprises a color filter substrate  111 , a thin film transistor (TFT) array substrate  112 , and a liquid crystal layer  114 . The liquid crystal layer  114  is packaged between the color filter substrate  111  and the TFT array substrate  112 . The driver chip  16  is disposed on the TFT array substrate  112  and also connected with a central control system (not shown) through another FPC  15 . The driver chip  16  is adapted to supply the driving voltage for the display module  11  to display an image. 
     However, the sensing structure  1  has the touch panel  12  to sense the touch. The touch panel  12  is an individual module of the sensing structure  1 , and the display module  11  is also an individual module of the sensing structure  1 . The touch panel  12  is attached on the display module  11  during the assembly process. In conventional display field, the sensor chip  13  is formed on the FPC  14  before it is electrically connected with the touch panel  12 . Such a chip-on-film (COF) process for bonding the sensor chip  13  onto the FPC  14  and subsequent bonding procedures entail a complex manufacturing process and require relatively expensive COF substrates. Therefore, the COF process inevitably leads to a complex process flow and high manufacturing cost. 
     In view of this, it is highly desirable in the field to provide a sensing structure that can be manufactured by a simple process at a low cost to solve the aforesaid problems encountered in the prior art. 
     SUMMARY OF THE INVENTION 
     One object of the present invention is to provide a sensing structure, in which a sensing unit and a chip is directly disposed on a display module without performing a COF process. The sensing structure of the present invention has a high integration, a relatively simplified manufacturing process, and a low manufacturing cost. 
     The sensing structure according to the present invention comprises a display module, a sensing unit, an electronic component and a cover lens. The display module has an active area. The sensing unit is disposed on the display module and overlaps at least part of the active area. The electronic component is disposed above the display module and outside the active area. A receiving space is formed on the cover lens to receive the electronic component and the electronic component is exposed through the receiving space. The cover lens uncovers the electronic component. 
     The detailed technology and preferred embodiments implemented for the subject invention are described in the following paragraphs accompanying the appended drawings for people skilled in this field to well appreciate the features of the claimed invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a conventional sensing structure; 
         FIG. 2  illustrates a sensing structure according to one embodiment of the present invention; 
         FIG. 3  illustrates a partial top view of the sensing structure according to one embodiment of the present invention; 
         FIG. 4  illustrates another embodiment of the sensing structure according to the present invention; 
         FIG. 5  illustrates a cover lens according to the present invention; and 
         FIG. 6  illustrates the preferred embodiment of the sensing unit according to the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 2  illustrates a sensing structure  2  disclosed in the present invention which comprises a display module  21 , a sensing unit  22  and a chip  23 . The display module  21  has an active area  20  to display an image. The sensing unit  22  is disposed on the display module  21  and overlaps at least part of the active area  20 . When physically contacted, the sensing unit  22  is adapted to generate a signal. 
     With reference to  FIGS. 2 and 3 ,  FIG. 3  illustrates a top view of an area enclosed by a dotted line in  FIG. 2 . To clearly depict the connection relationships of the sensing structure components, a cover lens  25  is omitted in  FIG. 3 . The chip  23  is disposed on the display module  21  and outside the active area  20  to avoid obstructing the image display of the active area  20 . The chip  23  is electrically connected with the sensing unit  22 . When being touched, the sensing unit  22  is adapted to generate a signal and transmit it to the chip  23  via a plurality of connecting wires  27 . Additionally, an FPC  24  has one end extended above the display module  21  and electrically connected with the chip  23  via another plurality of connecting wires  28 . Through the FPC  24 , the signals processed by the chip  23  are finally transmitted to a central control system (not shown) that is electrically connected with the other end of the FPC  24 . The dimensions, numbers, locations and distribution densities of the chip, the FPC and the connecting wires may be changed. One skilled in the art may make appropriate alterations depending on the practical requirements. Therefore, the present invention is not limited to the above description. 
     The display module  21  of the present invention comprises a first substrate  211  and a second substrate  212  disposed below the first substrate  211 . The first substrate  211  may be a color filter substrate, while the second substrate  212  may be a thin film transistor (TFT) array substrate. A liquid crystal layer  214  is packaged between the first substrate  211  and the second substrate  212 . The sensing structure  2  may further comprise a driver chip  26  disposed on the second substrate  212 . The driver chip  26  is configured to supply a driving voltage for the display module  21  to display an image. 
     With reference to  FIGS. 2 and 3 , the chip  23  is disposed on the display module  21  and electrically connected with the sensing unit  22 . The ways in which the chip  23  is electrically connected to the sensing unit  22  are as follows. For example, to increase the integration between the chip  23  and the sensing unit  22 , the chip  23  may be directly disposed on the first substrate  211  of the display module  21  for receiving signals of the sensing unit  22  via the connecting wires  27 . Alternatively, the chip  23  may be directly disposed on the sensing unit  22  as shown in  FIG. 4 . Because it is not necessary for the sensing structure  2  to perform a COF process for bonding the chip  23  onto the FPC  24 , there is a simpler manufacturing process and reduced manufacturing costs. Furthermore, the present invention can be embodied in fine pitch design of the connecting wires layout. 
     In a preferred embodiment, as shown in  FIG. 2 , the sensing structure  2  may comprise a cover lens  25  that covers at least part of the sensing unit  22 . The cover lens  25  protects the sensing unit  22  and the display module  21 . The chip  23  is directly disposed on the display module  21 . Hence, to decrease the total thickness of the sensing structure  2  and to planarize the surface of the sensing structure  2 , the cover lens  25  may be partially formed with a receiving space  250  to receive the chip  23 . Therefore, the disposition of the chip  23  on the display module  21  does not increase the total thickness of the sensing structure  2 . The receiving space  250  may be formed by partially thinning the cover lens  25  to form a recess at the location corresponding to the chip  23 . Alternatively, as shown in  FIG. 4 , a through-hole may be formed on the cover lens  25  so as to form a receiving space  250 ′ for accommodating the chip  23 . 
     Furthermore, the cover lens  25 , which is used for protecting the sensing unit  22  and the display module  21 , may be made of glass or hard polymer material. However, the above materials are only examples. The present invention is not limited to the above description. One skilled in the art may make appropriate alterations depending on the practical requirements. 
     As shown in  FIG. 5 , the cover lens  25  may comprise a body  251  and a border  252 . In a preferred embodiment, the body  251  is made of a transparent material, and the body  251  may substantially overlap the active area  20  ( FIG. 2 ) to show images without shelter. On the other hand, the border  252  may be opaque. For example, the border  252  may be printed or coated with a black pigment, adhered with an opaque adhesive tape, or be made of an opaque material. The way of making the border  252  is not limited to the above description. The border  252  lies substantially outside the range of the active area to shield the light and to prevent bright ribbon generated at the edge of the image. The ranges of the body  251  and the border  252  may be altered depending on the practical requirements. Alternatively, the border  252  may not exist in the cover lens  25  and the cover lens  25  is completely transparent. 
     The sensing unit of the present invention, either a capacitance sensing unit or a resistance sensing unit, may be selected by one skilled in the art depending on the practical requirements. Furthermore, the sensing unit may be a touch panel, a touch unit integrated with a display module, or other appropriate touch units. The touch panel, which is an independent device, can be directly disposed on the display module with an adhesive. The touch unit is integrated with a display module, so the touch function can be directly integrated into the display module during the manufacturing process without disposing an additional touch panel. Therefore, the total thickness of the display module with the integrated touch unit is approximately that of the original display module. In the preferred embodiment, the touch unit integrated with the display module is used as the sensing unit. 
     As shown in  FIG. 6 , the sensing unit  22  may be directly formed on the top surface of the first substrate  211 . The sensing unit  22  may comprise a conductive layer  221 , a polarizer  222 , an electrode layer  223  and a protective layer  224 . The electrode layer  223  is formed and patterned on the periphery of the top surface of the first substrate  211 . Then the conductive layer  221  is directly formed on the first substrate  211  to cover the electrode layer  223 . Additionally, the protective layer  224  may be formed on the conductive layer  221  to protect the conductive layer  221 . The polarizer  222  may be formed on the protective layer  224 . Alternatively, the protective layer  224  can be omitted and the polarizer  222  is directly attached onto the conductive layer  221 . The polarizer can maintain similar protective effect. The electrode layer  223  may be made of molybdenum (Mo)/aluminum (Al) (e.g., an Al layer is formed and then an Mo layer is formed), or of Mo/Al/Mo (e.g., an Mo layer, an Al layer and an Mo layer are formed in sequence). One skilled in the art may choose other proper material for the electrode layer depending on the practical requirements. The conductive layer  221  may be made of various transparent conductive oxides, such as indium tin oxide (ITO), indium oxide, silicon indium oxide, aluminum zinc oxide (AZO), indium zinc oxide (IZO), antimony tin oxide (ATO) or tin oxide. In this embodiment, the conductive layer  221  is preferably made of ITO. The protective layer  224  may be made of silicon nitrides (SiNx). Furthermore, the protective layer  224  may be replaced by the polarizer  222  which is formed directly on the conductive layer  221 . Therefore, the functions of polarizer  222  is not only polarizing the light but also protecting the conductive layer  221 . The touch unit integrated with the display module is an example of the sensing units. One skilled in the art may choose other kinds of touch units depending on practical requirements. 
     In conclusion, by directly disposing the chip on the display module, the sensing structure of the present invention can be manufactured through a relatively simpler and cheaper process. Furthermore, the present invention can be made in fine pitch design of the connecting wires layout. Since the cover lens may be stacked on the sensing unit and partially formed with the receiving space to accommodate the chip, the sensing structure will not have an increased thickness due to the disposition of the chip. When the touch unit integrated with the display module is used, the integration of the sensing unit will be further improved and the total thickness of the sensing structure will be reduced. Therefore, the present invention has advantages including total weight reduction, a reduced number of elements, and lowered cost. 
     The above disclosure is related to the detailed technical contents and inventive features thereof Persons having ordinary skill in the art may proceed with a variety of modifications and replacements based on the disclosures and suggestions of the invention as described without departing from the characteristics thereof Nevertheless, although such modifications and replacements are not fully disclosed in the above descriptions, they have substantially been covered in the following claims as appended.