Patent Publication Number: US-2013249816-A1

Title: Touch control device and touch control method using same providing environment compensation signal

Description:
BACKGROUND 
     1. Technical Field 
     The present disclosure relates touch control devices, and particularly to a touch control device which includes a primary touch panel for generating touch signals and a secondary touch panel for automatically providing an environment compensation signal. 
     2. Description of Related Art 
     Touch input devices, such as capacitive touch panels have been used widely in place of other input devices such as keypads. A capacitive touch panel may be attached to a display screen of a machine, such as a computer or smart phone for example, and configured for inputting signals. When a user presses the capacitive touch panel with his or her finger or a touch pen, electric charge distribution at the point of touch changes, and this change causes signal input and results in a corresponding response from the machine distribution of electric charge thereof. 
     However, this kind of touch panel can be overly sensitive to the environment and respond to changes in temperature humidity that result in false readings of touches. 
     Therefore, a new touch input device is needed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of at least one embodiment. In the drawings, like reference numerals designate corresponding parts throughout the various views. 
         FIG. 1  is a schematic block diagram of a touch input device provided by one embodiment of the present disclosure. 
         FIG. 2  is a timing diagram of the touch input device of  FIG. 1 . 
         FIG. 3  is a flowchart of an exemplary touch control method using the touch input device of the first embodiment. 
         FIG. 4  is an isometric view of a touch input device according to one embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made to the drawings to describe various embodiments in detail. 
     Referring to  FIG. 1 , a schematic block diagram of a touch input device  10  of one embodiment of the present disclosure is shown. The touch input device  10  includes a primary touch panel  101 , a primary touch driver  110 , an environmental compensation unit  103 , a control unit  104 , and an operation module  105 . In general, the word “module”, as used herein, refers to logic embodied in hardware or firmware, or to a collection of software instructions, written in a programming language, such as, Java, C, or Assembly. One or more software instructions in the modules may be embedded in firmware, such as in an EPROM. The modules described herein may be implemented as either software and/or hardware modules and may be stored in any type of non-transitory computer-readable medium or other storage device. Some non-limiting examples of non-transitory computer-readable medium include CDs, DVDs, BLU-RAY, flash memory, and hard disk drives. 
     The primary touch panel  101  is configured to receive a touch action such as a single touch from an object such as a stylus or fingertip for example. When a user touches the primary touch panel  101  with a fingertip or a stylus, electric charge distribution at the point of touch will change. In this embodiment, the primary touch panel  101  may be a resistance type touch panel or capacitance type touch panel. 
     The primary touch driver  110  is configured to detect a first change of electric charge distribution of the primary touch panel  101  and generate a corresponding touch signal “A.” 
     The environment compensation unit  103  is configured to sense second change of electric charge distribution caused by environment around the primary touch panel  101 , and generate a compensating signal “B” accordingly. The compensating signal “B” compensates for environmentally generated change of electric charge distribution thus preventing false touch readings. 
     In one embodiment, the compensation unit  103  includes a secondary touch panel  102  and a secondary touch driver  120 . In this embodiment, the secondary touch panel  102  is configured to respond to changes of electric charge distribution of secondary touch panel  102  in the same way as the primary touch panel  101  and can be made of the same materials as the primary touch panel  101 . The secondary touch panel  102  is configured in a way that prevents a user touching it so that any changes in of electric charge distribution (hereafter called “a second change of electric charge distribution”) may be considered to be solely caused by the environment around the touch input device  10 . In one embodiment, a cover overlapping the secondary touch panel  102  may be set to prevent the user from touching the secondary touch panel  102 . 
     The secondary touch driver  120  is configured to detect the second change of electric charge distribution, and generate the compensating signal “B” accordingly. 
     The control unit  104  includes a select switch  141 , an analog/digital (A/D) converter  143 , and a processor  145 . 
     The select switch  141  includes two inputs correspondingly connected to the primary touch driver  110  and the secondary touch driver  120 , an output connected to the A/D converter  143 , and a control terminal connected to the processor  145 . The select switch  141  is configured to selectively transmit the touch signal “A” or the compensating signal “B” to the processor  145  via the A/D converter  143 . In one embodiment, the select switch  141  may be a time division multiplexing switch. 
     The A/D converter  143  receives the touch signal “A” and the compensating signal “B” from the primary touch driver  110  and the secondary touch driver  120  respectively, transforms the touch signal “A” and the compensating signal “B” from analog signals into digital signals, and sends them to the processor  145 . 
     In one embodiment, the touch signal “A” and the compensating signal “B” are sequentially sent to the processor  145  in a time division mode as shown in  FIG. 2 . In detail, in a first time period “T 1 ”, the select switch  141  transmits the touch signal “A” to the processor  145  via the A/D converter  143 . In a second time period “T 2 ”, which follows the first time period “T 1 ”, the select switch  141  transmits the compensating signal “B” to the processor  145  via the A/D converter  143 . 
     The processor  145  processes the touch signal “A” and the compensating signal “B” to generate a control signal “C” which is essentially touch signal “A” minus any environmentally induced change of electric charge distribution. In one embodiment, the processor  145  subtracts the compensating signal “B” from the touch signal “A” to generate the control signal “C”. The processor  145  then compares the control signal “C” with a predetermined reference value. If the control signal “C” is greater than the predetermined reference value, the processor  145  provides the control signal “C” to the operation module  105 . If the control signal “C” is less than the predetermined reference value, the control signal “C” will not be provided to the operation module  105 . 
     The operation module  105  is configured to receive the control signal “C” and perform a corresponding function related to a touch position of the primary touch panel  101 . 
     Referring to  FIG. 3 , a flowchart of an exemplary touch control method using the touch input device  10  of the first embodiment is shown. The touch control method includes the following steps. Depending on the embodiment, additional steps may be added, others removed, and the ordering of the steps may be changed. 
     In step S 101 , the primary touch panel  101  is touched by a user to generate a first change of electric charge distribution. The primary touch driver  110  is configured to detect the first change of electric charge distribution and in response generate a touch signal “A”. 
     In step S 102 , the environment around the primary touch panel  101  which may influence the change of electric charge distribution of the primary touch panel  101  is sensed. In detail, the secondary touch panel  102  is configured to generate a second change of electric charge distribution without the touch of the user and the secondary touch driver  120  is configured to sense the second change of electric charge distribution to generate a compensating signal “B”. 
     In step S 103 , the touch signal “A” and the compensating signal “B” are selectively transmitted to the A/D converter  143  and transformed into digital signals. The touch signal “A” and the compensating signal “B” are then transmitted to the processor  145 . 
     In step S 104 , the processor  145  processes the touch signal “A” and the compensating signal “B” to generate a control signal “C” which minus any environmentally induced change of electric charge distribution. 
     In step S 105 , a corresponding function is performed by the operation module  105  according to the control signal “C” if the control signal “C” is greater than a predetermined reference value. 
     Referring to  FIG. 4 , an isometric view of a touch input device  20  according to one embodiment of the present disclosure is shown. In one embodiment, the touch input device  20 , for example, is a mobile phone. The touch input device  20  includes a housing  21 . The primary touch panel  101  and the secondary touch panel  102  are disposed on a surface of the housing  21  and arranged adjacent to each other. In one embodiment, an area of the primary touch panel  101  is much larger than that of the secondary touch panel  102 . 
     It is to be understood that even though numerous characteristics and advantages of the present embodiments have been set forth in the foregoing description, with details of the structures and functions of the embodiments, the disclosure is illustrative only; and that changes may be in detail, especially in matters of shape, size, and arrangement of parts, within the principles of the embodiments, to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.