201126401 六、發明說明： 【發明所屬之技術領域】 本發明係關於觸控面板之技術領域，尤指一種差動 偵測電容式觸控的解調變方法及系統。 【先前技術】 現代消費性電子裝置多配備觸控板做為其輸入裝置 之一。為符合輕、薄、短、小等需求，觸控板亦多與面 板整合成為觸控面板，用以方便使用者輸入。觸控板根 β 據感測原理的不同可分為電阻式、電容式、音波式、及 光學式等四種。 觸控面板的技術原理是當手指或其他介質接觸到螢 幕時，依據不同感應方式，偵測電壓、電流、聲波或紅 外線等，進而測出觸壓點的座標位置。例如電阻式即為 利用上、下電極間的電位差，用以計算施壓點位置檢測 出觸控點所在。電容式觸控面板是利用排列之透明電極 與人體之間的靜電結合所產生之電容變化，從所產生之 春 電流或電壓來檢測其座標。 圖1係習知電容式觸控面板的驅動之示意圖，其係用 以驅動一nxm觸控面板，其中，n，m為大於丨之整數。 如圖1所示，一驅動電路（圖未示）依序在一個方向的導體 線X〗，X2，X3,…上產生一驅動訊號Vy ,經由導體線幻 X2, X3,…及導體線γι，γ2, γ3，之間的互感電容 Cm(mutual capacitance)，搞合電荷進人導體線η, w 4 201126401 Y3,…。偵測電路丨1()藉由η個感測電路（圖未示）透過量測 電荷’進而產生電壓訊號V⑴，V(2)，V(3),…,V(n)。 當沒有接地導體或手指靠近觸控面板時互感電容 Cm的大小為CmO。當有接地導體或手指靠近觸控面板 時’會干擾導體線XI，X2, X3,…及導體線Yl，Y2, Y3，... 之間的電力線’進而會影響互感電容Cm的大小（假設接觸 時大小為Cml) »偵測電路Π0透過互感電容Cm的變化而 鲁 量測電荷，進而產生電壓訊號V(l)，V(2)，V(3)，…,V(n)。 可程式增益碑大器U0將電壓訊號V(i)，V(2)， ν(3)，···，ν(η)放大至類比至數位轉換器n〇的輸入範圍，而 產生電壓訊號Va(l)，Va(2)，Va(3)，...，Va(n)。類比至數位 轉換器130則將電壓訊號Va(1)〜va(n)轉換成數位訊號 D(l)〜D(n)。 偏移裝置140調整D(1)〜D(n)的偏移量，調整後的 D(l)〜D(n)寫入圖框緩衝器15〇中，成為導體線χι的相關 資料。驅動電路依序在導體線X2，Χ3,…上產生一驅動訊 • 號Vy，並重複以上的動作，得到每一條導體線Χ2, Χ3,… 的相關資料。 當湊齊整個圖框緩衝器丨5〇中的資料後，經由座標判 斷裝置160判斷是否有導體或手指觸碰面板導致耦合電 荷量改變而造成D(l)-K〜D(n)-K的改變，若判斷為導體或 手指則進行座標計算進而產生接觸點座標。 當導體或手指罪近或觸碰面板時，互感電容Cm的變 化量非常小，因而容易受受到外來的共同雜訊（c〇mm〇n noise)的影響，共同雜訊經由可程式增益放大器12〇放大 201126401 後’則降低整個系統的訊號雜訊比（Signal t〇 N〇ise Rati〇, SNR) ’因而偏移裝置140輸出的訊號D(l)-K〜D(n)-K會因 具有較多雜訊而有抖動現象’進而造成座標判斷裝置16〇 所產生接觸點座標的不穩定，甚至不正確。因此，習知 偵測電容式觸控面板的技術，仍有改善的空間。 【發明内容】 本發明之目的主要係在提供差動偵測電容式觸控的 解調變方法及系統’以降低共同雜訊（Common Noise)的 影響’並獲得最佳的訊號雜訊比，進而提高接觸點座標 的準確度。 依據本發明之一特色，本發明提出一種差動偵測電 容式觸控的解調變系統，其用於一電容式觸控面板，該 電谷式觸控面板具有分佈在第一方向之η條導體線及分 佈在第二方向之m條導體線’ n，m為大於1之整數，該第一 方向導體線與第二方向導體線之間的相疊處形成感應電 谷’該第一方向係垂直於該第二方向，該系統包含一债 測電路、一組減法器、一組可程式增益放大器、一類比 至數位轉換器、及一解調變裝置。該偵測電路具有η個輸 入端’用以偵測電容式觸控面板之η條導體線的感應電 谷’並產生相對應的η個感應訊號，。該組減法器連接至 δ亥倘測電路’其具有η-1個減法器’以對該偵測電路輸出 的鄰近兩條導體線之感應訊號兩兩相減’以產生^丨個的 差動訊號。該組可程式增益放大器連接至該組減法器， 以對該η-1個的差動訊號進行放大，以產生η· 1個放大差動 6 201126401 訊號。該類比至數位轉換器連接至該組可程式增益放大 器’以將該n-l個放大差動訊號轉換為n-l個數位差動訊 號。該解調變裝置連接至該類比至數位轉換器，將該nq 個數位差動訊號解調變為η個數位訊號。其中，該組減法 器係在該組可程式增益放大器之前將該電容式觸控面板 之η條導體線的共同雜訊（Common noise)移除，以免該共 同雜訊被該組可程式增益放大器放大。 依據本發明之另一特色，本發明提出一種差動偵測 電容式觸控的解調變方法，其用以偵測一物件是否觸碰 該電容式觸控面板，該電容式觸控面板在第一方向有η條 導體線，在第二方向有m條導體線，n，m為大於1之整數， 該第一方向導體線與第二方向導體線之間的相疊處形成 感應電容’該第一方向係垂直於該第二方向，該方法包 含：（A)使用一偵測電路以偵測一電容式觸控面板之η條 導體線的感應電容，並產生相對應的η個感應訊號；（β) 使用一組減法器以對該偵測電路輸出的鄰近2條導體線 之感應訊號兩兩相減，以產生η-1個的差動訊號；（〇使用 一組可程式增益放大器，以對該n-l個的差動訊號進行放 大，以產生n-l個放大差動訊號；（D)使用一類比至數位轉 換器’以將該η-1個放大差動訊號轉換為η-1個數位差動訊 號；（Ε)使用一解調變裝置，以將將該n-l個數位差動訊號 解調變為η個數位訊號；其中，該組減法器係在該组可程 式增益放大器之前將該電容式觸控面板η條線的共同雜 訊（common noise)移除’以免該共同雜訊被該組可程式增 益放大器放大。 201126401 【實施方式】 圖2係本發明一種差動偵測電容式觸控的解調變系 統的方塊圖，該解調變系統包含：一偵測電路21〇、一組 減法器220、一組可程式增益放大器23〇、一類比至數位 轉換器240、一解調變裝置25〇、一偏移裝置26〇、一圖框 緩衝器270、及一座標判斷裝置28〇。 該偵測電路210其具有1!個輸入端，用以偵測一電容 式觸控面板290之η條導體線的感應電容，進而產生相對 應的η個感應訊號。 於本發明中，該感應訊號可為感應電壓或感應電 流’為方便說明’於本實施例中以感應電壓為例，該偵 測電路210產生相對應的η個感應電壓ν( 1)〜ν(η)。 如圖2所示，該電容式觸控面板29〇in條導體線係分 佈在第一方向，該電容式觸控面板290在第二方向更有m 條導體線，該第一方向導體線與第二方向導體線之間的 相疊處形成感應電容Cm，其中’該第一方向係垂直於該 第一方向，m為大於1之整數，η為大於1之整數； 該組減法器220連接至該偵測電路21 〇，其具有η_ 1個 減法器，用以對該偵測電路輸出的鄰近兩條導體線之感 應電壓進行兩兩相減’進而產生η· 1個的差動訊號。 於本發明中’該差動訊號可為差動電壓或差動電 流’為方便說明’於本實施例申以差動電壓為例，該組 減法器220產生相對應的η個差動電壓v(2)-V(l), 201126401 V(3)-V(2)，…，V(n)-V(n-1)»該n-l個減法器較佳為類比減 法器’並且可為差動放大器（Differential Amplifier)。 其中，第i個類比減法器接收第i+1個感應電壓V(i+1) 及一第i個感應電壓V(i)，並將該第i+1個感應電壓V(i+1) 減去該第i個感應電壓V(i)，而產生一第i個差動電壓 V(i+1)-V(i)，當中，i=l，2, 3，...，η-I。 該組可程式增益放大器230連接至該組減法器220， 用以對該η-I個的差動電壓V(2)-V(l)，V(3)-V(2)，...， • V(n)-V(n-1)進行放大，進而產生η-i個放大差動訊號。於 本發明中’該放大差動訊號可為放大差動電壓或放大差 動電流’為方便說明，於本實施例中以放大差動電壓為 例，該組可程式增益放大器230產生相對應的n個放大差 動電壓 Va(2)-Va(l)，Va(3)-Va(2)，…，Va(n)-Va(n-1)，其 中，該n-1個放大差動電壓係符合該類比至數位轉換器 240的輸入範圍，用以降低類比至數位轉換時的量化誤差 (Quantization Error)。 φ 於本發明中，該組減法器220係在該組可程式增益放 大器230之前將該電容式觸控面板之η條導體線的共同雜 訊（Common noise)移除，進而避免該共同雜訊被該組可程 式增益放大器放大’藉此以降低共同雜訊的影響，並獲 得最佳的訊號雜訊比，進而提高接觸點座標的準確度。 該類比至數位轉換器240連接至該組可程式增益放 大器230 ’以將該η-I個放大差動電壓va(2)-va(i) Va(3)-Va(2)，…，Va(n)-Va(n-1)轉換為n-l個數位差動訊 號 D(2)-D(l)，D(3)-D(2)，…，D(n)-D(n-1)。 201126401 該解調變裝置250連接至該類比至數位轉換器240， 將該n-1個數位差動訊號d(2)-D(1)，D(3)-D(2)，...， D(n)-D(n-1)解調變為n個數位訊號d(1)-D(1)， D(2)-D(l)，...，D(n)-D(l)。 圖3係本發明該解調變裝置250之運作的示意圖。其 輸入端接收n-Ι個數位差動訊號d(2)-D(1)，D(3)-D(2)，...， D(n)-D(n-1) ’該解調變裝置250直接輸出D(l)-D(l)、 D(2)-D(l)為第1個數位訊號及第2個數位訊號。 該解調變裝置250並將第2個數位差動訊號D(3)-D(2) # 與第1個數位差動訊號D(2)-D(l)相加，而產生第3個數位 訊號D(3)-D(l)。再將第3個數位訊號d(3)-D(1)與第3個數 位差動訊號D(4)-D(3)相加，而產生第4個數位訊號 D(4)-D(l) ’依序類推’不再予以贅述。 亦即’該解調變裝置250將第i個數位差動訊號與第i 個數位訊號相加’而產生第i+丨個數位訊號，當十，丨=2， 3,..., n-1 〇 該偏移裝置260連接至該解調變裝置250，用以將該〇 ^ 個數位訊號進行偏移調整，進而產生η個偏移訊號。 該偵測電路110透過互感電容Cm的變化，其係相對 值’故該偏移裝置260係對該n個數位訊號加上一可程式 固定值Κ，而產生η個偏移訊號。當可程式固定值反為口㈠） 時，該η個偏移訊號為D(1)_K，D(2)_K，，D(n)_K。於其他 實施例中，可程式固定值尺可為D(1)，D(2)， ，D(n)中的 最小值，亦即 K=min{D(l)，D(2)，…，D(n)}。 10 201126401 本發明中，依序驅動該電容式觸控面板29〇的111條導 體線XI，X2,…，xm，並依序儲存條導體線χι, χ2，…，Xm 對應的η個偏移訊號。故該圖框緩衝器27〇連接至該偏移 裝置260,以暫存該偏移裝置依序輸出的〇1組11個偏移訊 號》 該座標判斷裝置280連接至該圖框緩衝器270，依據 該mxn個偏移訊號的變化，以判斷是否有接地導體或一手 指觸碰該電容式觸控面板。 圖4係本發明一種差動偵測電容式觸控的解調變方 法的流程圖，並請參照圖2所示之差動偵測電容式觸控的 解調變系統的方塊圖，該解調變方法用以偵測—物件是 否觸碰該電容式觸控面板290，該電容式觸控面板290在 第一方向有η條導體線，在第二方向有m條導體線，該第 一方向導體線與第二方向導體線之間的相疊處形成感應 電容，該第一方向係垂直於該第二方向。 首先於步驟S410中，使用一偵測電路210以偵測一電 容式觸控面板290之η條導體線的感應電容，並產生相對 應的η個感應訊號V(l)〜V(n)。 於步驟S420中，使用一組減法器220以對該偵測電路 輸出的鄰近2條導體線之感應訊號兩兩相減，進而產生 n-1個的差動訊號 V(2)-V(l)，V(3)-V(2)，…，V(n)-V(n-1)。 其中，第i個類比減法器接收一第i+1個感應訊號V(i + 1)及 一第i個感應訊號V(i) ’並將該第i+Ι個感應訊號V(i+1)減 去該第i個感應訊號V(i)，進而產生一第i個差動訊號 V(i+1)-V(i)，當中 ’ i=l，2, 3，..·，η-I。 11 201126401 於步驟S430中，使用一組可程式增益放大器230，以 對該 n-1 個的差動訊號 V(2)-V(l)， V(3)-V(2)，...， V(n)-V(n-1)進行放大，進而產生n-1個放大差動訊號 Va(2)-Va(l)，Va(3)-Va(2)，…，Va(n)-Va(n-1) » 本發明係在步驟S420中先將η條線的鄰近2條導體線 之感應訊號兩兩相減，用以將共同雜訊（common noise) 移除，以免該共同雜訊於步驟S430中被放大。 於步驟S440中，使用一類比至數位轉換器240,以將 該 η·1 個放大差動訊號 Va(2)-Va(l)，Va(3)-Va(2)，...， #201126401 VI. Description of the Invention: [Technical Field] The present invention relates to the technical field of touch panels, and more particularly to a method and system for demodulating and changing differential capacitive touch. [Prior Art] Modern consumer electronic devices are often equipped with a touch panel as one of their input devices. In order to meet the needs of light, thin, short and small, the touchpad is also integrated with the panel to form a touch panel for user input. The touchpad root β can be divided into four types: resistive, capacitive, sonic, and optical. The technical principle of the touch panel is to detect the voltage, current, sound wave or infrared line according to different sensing methods when the finger or other medium touches the screen, and then measure the coordinate position of the touch point. For example, the resistive type uses the potential difference between the upper and lower electrodes to calculate the position of the pressure point to detect the touch point. The capacitive touch panel detects the coordinates of the generated spring current or voltage by utilizing the capacitance change generated by the electrostatic combination between the arranged transparent electrodes and the human body. 1 is a schematic diagram of a conventional capacitive touch panel driving for driving an nxm touch panel, wherein n, m are integers greater than 丨. As shown in FIG. 1, a driving circuit (not shown) sequentially generates a driving signal Vy on a conductor line X, X2, X3, ... in one direction, via a conductor line X2, X3, ... and a conductor line γι. , γ2, γ3, mutual capacitance Cm (mutual capacitance), engage the charge into the conductor line η, w 4 201126401 Y3,... The detecting circuit 丨1() generates voltage signals V(1), V(2), V(3), ..., V(n) by measuring the charge by n sensing circuits (not shown). When there is no grounding conductor or the finger is close to the touch panel, the size of the mutual inductance capacitor Cm is CmO. When there is a grounding conductor or a finger close to the touch panel, 'the power line that interferes with the conductor lines XI, X2, X3, ... and the conductor lines Y1, Y2, Y3, ...' will affect the size of the mutual inductance capacitor Cm (hypothesis) The contact size is Cml) » The detection circuit Π0 measures the charge through the change of the mutual inductance capacitor Cm, and then generates the voltage signals V(l), V(2), V(3), ..., V(n). The programmable gain monument U0 amplifies the voltage signals V(i), V(2), ν(3), ···, ν(η) to analogy to the input range of the digital converter n〇, and generates a voltage signal Va(l), Va(2), Va(3), ..., Va(n). The analog to digital converter 130 converts the voltage signals Va(1) to va(n) into digital signals D(l)~D(n). The offset device 140 adjusts the offset amounts of D(1) to D(n), and the adjusted D(1) to D(n) are written in the frame buffer 15A to become the relevant data of the conductor lines. The driving circuit sequentially generates a driving signal Vy on the conductor lines X2, Χ3, ..., and repeats the above operations to obtain related information of each of the conductor lines Χ2, Χ3, . After the data in the entire frame buffer 丨5〇 is collected, it is determined by the coordinate determining device 160 whether or not a conductor or a finger touches the panel, causing a change in the amount of coupled charge to cause D(l)-K~D(n)-K. The change, if judged as a conductor or a finger, performs coordinate calculation to generate contact point coordinates. When the conductor or finger sin is near or touches the panel, the variation of the mutual inductance capacitor Cm is very small, so that it is susceptible to external common noise (c〇mm〇n noise), and the common noise is passed through the programmable gain amplifier 12 〇Amplification 201126401 'then reduces the signal noise ratio of the whole system (Signal t〇N〇ise Rati〇, SNR)' and thus the signal D(l)-K~D(n)-K output by the offset device 140 will be There is more noise and jitter phenomenon, which in turn causes instability or even incorrectness of the contact point coordinates generated by the coordinate determining device 16〇. Therefore, there is still room for improvement in the technique of detecting a capacitive touch panel. SUMMARY OF THE INVENTION The object of the present invention is to provide a differential detection method and system for differential detection capacitive touch to reduce the influence of common noise and obtain the best signal noise ratio. In turn, the accuracy of the contact point coordinates is improved. According to a feature of the present invention, the present invention provides a differential detection capacitive touch demodulation system for a capacitive touch panel having a η distributed in a first direction. The strip conductor lines and the m conductor lines 'n,m distributed in the second direction are integers greater than 1, and the overlap between the first direction conductor line and the second direction conductor line forms an induced electric valley' The direction is perpendicular to the second direction, and the system includes a debt measurement circuit, a set of subtractors, a set of programmable gain amplifiers, an analog to digital converter, and a demodulation device. The detecting circuit has n input terminals s for detecting the induced valleys of the n conductor lines of the capacitive touch panel and generating corresponding n sensing signals. The set of subtractors is connected to the delta-sampling circuit 'which has n-1 subtractors' to subtract the two inductive signals of the adjacent two conductor lines outputted by the detecting circuit to generate a differential Signal. The set of programmable gain amplifiers is coupled to the set of subtractors to amplify the η-1 differential signals to produce η·1 amplified differentials 6 201126401 signals. The analog to digital converter is coupled to the set of programmable gain amplifiers to convert the n-1 amplified differential signals into n-1 digital differential signals. The demodulation device is coupled to the analog to digital converter to demodulate the nq digital differential signals into n digital signals. The group of subtractors remove common noise of the n conductor lines of the capacitive touch panel before the set of programmable gain amplifiers, so as to prevent the common noise from being used by the set of programmable gain amplifiers. amplification. According to another feature of the present invention, the present invention provides a method for detecting and detecting a differential touch capacitive touch, which is used to detect whether an object touches the capacitive touch panel, and the capacitive touch panel is There are n conductor lines in the first direction, m conductor lines in the second direction, n, m is an integer greater than 1, and the sensing capacitance is formed at the overlap between the first direction conductor line and the second direction conductor line. The first direction is perpendicular to the second direction, and the method includes: (A) using a detecting circuit to detect the sensing capacitance of the n conductor lines of a capacitive touch panel, and generating corresponding n senses Signal (β) uses a set of subtractors to subtract the two sensing signals of the adjacent two conductor lines output from the detecting circuit to generate η-1 differential signals; (〇 using a set of programmable gains An amplifier for amplifying the n1 differential signals to generate n1 amplified differential signals; (D) using an analog to digital converter to convert the η-1 amplified differential signals to η-1 a digital differential signal; (Ε) using a demodulation device to Demodulating the nl digital differential signal into n digital signals; wherein the set of subtractors is common noise of the n-line of the capacitive touch panel before the set of programmable gain amplifiers Removing the 'to avoid the common noise being amplified by the set of programmable gain amplifiers. 201126401 Embodiment 2 FIG. 2 is a block diagram of a differential detection capacitive touch demodulation system of the present invention, the demodulation system The method includes a detection circuit 21A, a set of subtractor 220, a set of programmable gain amplifiers 23A, an analog to digital converter 240, a demodulation device 25A, an offset device 26A, and a frame. The buffer circuit 270 and the flag determining device 28. The detecting circuit 210 has 1! input terminals for detecting the sensing capacitance of the n conductor lines of a capacitive touch panel 290, thereby generating corresponding η sensing signals. In the present invention, the sensing signal can be an induced voltage or an induced current 'for convenience of description'. In the present embodiment, an induced voltage is taken as an example, and the detecting circuit 210 generates corresponding n induced voltages ν (1)~ν(η) As shown in FIG. 2, the capacitive touch panel 29〇in strip conductors are distributed in a first direction, and the capacitive touch panel 290 has more m conductor lines in the second direction, and the first direction conductor lines are The junction between the second directional conductor lines forms a sensing capacitance Cm, wherein 'the first direction is perpendicular to the first direction, m is an integer greater than 1, and η is an integer greater than 1; the set of subtractors 220 are connected The detecting circuit 21 具有 has η_1 subtractors for performing two-two subtraction of the induced voltages of the adjacent two conductor lines outputted by the detecting circuit to generate η·1 differential signals. In the present invention, the differential signal may be a differential voltage or a differential current. For convenience of description, in the embodiment, a differential voltage is applied as an example, and the group of subtractors 220 generates corresponding n differential voltages. (2) -V(l), 201126401 V(3)-V(2),...,V(n)-V(n-1)»The nl subtractors are preferably analog subtractors' and may be poor Differential Amplifier. The i-th analog subtractor receives the (i+1)th induced voltage V(i+1) and an ith induced voltage V(i), and the (i+1)th induced voltage V(i+1) Subtracting the ith induced voltage V(i) to generate an i-th differential voltage V(i+1)-V(i), where i=l, 2, 3, ..., η- I. The set of programmable gain amplifiers 230 are coupled to the set of subtractors 220 for the η-I differential voltages V(2)-V(l), V(3)-V(2),... • V(n)-V(n-1) is amplified to generate η-i amplified differential signals. In the present invention, the amplified differential signal can be amplifying the differential voltage or amplifying the differential current. For convenience of description, in the embodiment, the amplified differential voltage is taken as an example, and the programmable gain amplifier 230 generates a corresponding one. n amplification differential voltages Va(2)-Va(l), Va(3)-Va(2), ..., Va(n)-Va(n-1), wherein the n-1 amplification differences The voltage is in accordance with the analog input to the input range of the digital converter 240 to reduce the Quantization Error during analog to digital conversion. In the present invention, the group of subtractors 220 remove common noise of the n conductor lines of the capacitive touch panel before the set of programmable gain amplifiers 230, thereby avoiding the common noise. It is amplified by this set of programmable gain amplifiers to reduce the effects of common noise and obtain the best signal-to-noise ratio, thus improving the accuracy of contact point coordinates. The analog to digital converter 240 is coupled to the set of programmable gain amplifiers 230' to amplify the differential voltages va(2) - va(i) Va(3) - Va(2), ..., Va (n)-Va(n-1) is converted into nl digital differential signals D(2)-D(l), D(3)-D(2),...,D(n)-D(n-1 ). 201126401 The demodulation device 250 is connected to the analog to digital converter 240, the n-1 digital differential signals d(2)-D(1), D(3)-D(2),... , D(n)-D(n-1) demodulation becomes n digital signals d(1)-D(1), D(2)-D(l),...,D(n)-D (l). 3 is a schematic diagram of the operation of the demodulation device 250 of the present invention. The input terminal receives n-Ι digital differential signals d(2)-D(1), D(3)-D(2),..., D(n)-D(n-1) 'the solution The modulation device 250 directly outputs D(l)-D(l), D(2)-D(l) as the first digital signal and the second digital signal. The demodulation device 250 adds the second digital differential signal D(3)-D(2)# to the first digital differential signal D(2)-D(l) to generate the third Digital signal D(3)-D(l). The third digital signal d(3)-D(1) is added to the third digital differential signal D(4)-D(3) to generate a fourth digital signal D(4)-D ( l) 'Sequential analogy' will not be repeated. That is, the demodulation device 250 adds the i-th digital differential signal to the ith digital signal to generate the i-th digital signal, when ten, 丨=2, 3,..., n- The offset device 260 is coupled to the demodulation device 250 for offset-adjusting the digital signals to generate n offset signals. The detecting circuit 110 transmits a change in the mutual inductance Cm, which is a relative value. Therefore, the offset device 260 adds a programmable fixed value 对该 to the n digital signals to generate n offset signals. When the programmable fixed value is reversed to (1), the n offset signals are D(1)_K, D(2)_K, and D(n)_K. In other embodiments, the programmable fixed value scale can be the minimum value of D(1), D(2), and D(n), that is, K=min{D(l), D(2),... , D(n)}. 10 201126401 In the present invention, 111 conductive lines XI, X2, ..., xm of the capacitive touch panel 29A are sequentially driven, and n shifts corresponding to the strip conductor lines χι, χ2, ..., Xm are sequentially stored. Signal. Therefore, the frame buffer 27 is connected to the offset device 260 to temporarily store the 11 sets of 11 offset signals sequentially output by the offset device. The coordinate determining device 280 is connected to the frame buffer 270. According to the change of the mxn offset signals, it is determined whether a ground conductor or a finger touches the capacitive touch panel. 4 is a flow chart of a method for demodulating a differential detection capacitive touch according to the present invention, and referring to a block diagram of a differential detection capacitive touch demodulation system shown in FIG. 2, the solution The modulation method is configured to detect whether the object touches the capacitive touch panel 290. The capacitive touch panel 290 has n conductor lines in a first direction and m conductor lines in a second direction. A junction between the directional conductor line and the second directional conductor line forms an induced capacitance, the first direction being perpendicular to the second direction. First, in step S410, a detecting circuit 210 is used to detect the sensing capacitance of the n conductor lines of a capacitive touch panel 290, and corresponding n sensing signals V(1) VV(n) are generated. In step S420, a set of subtractors 220 are used to subtract the two sensing signals of the adjacent two conductor lines outputted by the detecting circuit, thereby generating n-1 differential signals V(2)-V(l ), V(3)-V(2), ..., V(n)-V(n-1). The i-th analog subtractor receives an i+1th inductive signal V(i+1) and an i-th inductive signal V(i)' and the i+th inductive signal V(i+1) Subtracting the ith sensing signal V(i), thereby generating an ith differential signal V(i+1)-V(i), where 'i=l, 2, 3, .., η -I. 11 201126401 In step S430, a set of programmable gain amplifiers 230 are used to the n-1 differential signals V(2)-V(l), V(3)-V(2),... , V(n)-V(n-1) is amplified to generate n-1 amplified differential signals Va(2)-Va(l), Va(3)-Va(2),...,Va(n -Va(n-1) » The present invention first subtracts the sensing signals of the adjacent two conductor lines of the n lines in step S420 to remove common noise, so as to avoid the The common noise is amplified in step S430. In step S440, an analog-to-digital converter 240 is used to amplify the differential signals Va(2)-Va(l), Va(3)-Va(2), ..., #
Va(n)-Va(n-1)轉換為n-1個數位差動訊號D(2)-D(l)， D(3)-D(2)，…，D(n)-D(n-1)。 於步驟S450中，使用一解調變裝置250，以將該n-i 個數位差動訊號D(2)-D(l)，D(3)-D(2)，…，D(n)-D(n-1)解 調變為 η 個數位訊號 D(l)-D(l), D(2)-D(l)，...，D(n)-D ⑴。 該解調變裝置250並將第2個數位差動訊號d(3)-D(2) 與第1個數位差動訊號D(2)-D(l)相加，而產生第3個數位 訊號D(3)-D(l)。再將第3個數位訊號D(3)-D(l)與第3個數 鲁 位差動訊號D(4)-D(3)相加’而產生第4個數位訊號 D(4)-D(l) ’依序類推’不再予以贅述。亦即，該解調變 裝置250將第i個數位差動訊號與第丨個數位訊號相加而 產生第i+Ι個數位訊號，當令，i=2, 3， ，n l。 於步驟S460中，使用一偏移裝置26〇，以將該n個數 位訊號進行偏移調整，而產生n個偏移訊號。該偵測電路 110透過互感電容Cm的變化，其係相對值，故該偏移裝置 係對該η個數位訊號加上一可程式固定值κ，而產生η個偏 12 201126401 移訊號。當可程式固定值1^為0(1)時，該n個偏移訊號為 D(l)-K，D(2)-K，··.，D(n)-K。於其他實施例中，可程式固 定值尺可為〇(1)，0(2)，...，1)(11)中的最小值，亦即 K=min{D(l)，D(2)，…，D(n)}。 於步驟S470中，使用一圖框緩衝器27〇，以暫存該偏 移裝置依序輸出m組的η個偏移訊號；以及 於步驟S480中，使用一座標判斷裝置，依據該爪… 個偏移sTl號的變化，進而判斷是否有接地導體或一手指 觸碰該電容式觸控面板。 由前述說明可知，本發明在類比電路之前端採用差 動相減架構，用以偵測在第一方向上所有鄰近2條導體線 的號差值，以降低共同雜訊（C〇mm〇n N〇ise)，並提昇 訊號雜訊比（SNR)，進而提高接觸點座標判斷的準確度。 同時依據本發明技術，在第一方向上鄰近導體線之間的 間距可以降低，不必擔心因導體線靠太近而會同時觸摸 到兩條導體線時，並同時在兩條導體線產生訊號而造成 讯號相互減除的問題，因此可提昇電容式觸控面板導體 線的解析度。 由上述可知，本發明無論就目的、手段及功效，在 在均顯示其迥異於習知技術之特徵，極具實用價值。惟 應注意的是，上述諸多實施例僅係為了便於說明而舉例 而已，本發明所主張之權利範圍自應以申請專利範圍所 述為準’而非僅限於上述實施例。 【圖式簡單說明】 13 201126401 圖1係習知電容式觸控面板的驅動之示意圖。 圖2係本發明一種差動偵測電容式觸控的解調變系統的 方塊圖。 圖3係本發明該解調變裝置之運作的示意圖。 圖4係本發明一種差動偵測電容式觸控的解調變方法的 流程圖。 【主要元件符元說明】 可程式增益放大器120 φ 偏移裝置140 座標判斷裝置160 減法器220 類比至數位轉換器240 偏移裝置260 座標判斷裝置280 偵測電路11 〇 類比至數位轉換器130 圖框緩衝器150 偵測電路21 〇 可程式增益放大器230 解調變裝置250 圖框緩衝器270 電容式觸控面板290 步驟S410〜S480 14Va(n)-Va(n-1) is converted into n-1 digital differential signals D(2)-D(l), D(3)-D(2),...,D(n)-D( N-1). In step S450, a demodulation device 250 is used to the ni digital differential signals D(2)-D(1), D(3)-D(2),...,D(n)-D. (n-1) Demodulation becomes n digital signals D(l)-D(l), D(2)-D(l), ..., D(n)-D(1). The demodulation device 250 adds the second digital differential signal d(3)-D(2) to the first digital differential signal D(2)-D(l) to generate a third digit. Signal D(3)-D(l). Then, the third digital signal D(3)-D(l) is added to the third number of lube differential signals D(4)-D(3) to generate a fourth digital signal D(4)- D(l) 'Sequential analogy' will not be repeated. That is, the demodulation device 250 adds the i-th digital differential signal and the third digital signal to generate an i-th digital signal, and when so, i=2, 3, , n l. In step S460, an offset device 26A is used to offset the n digital signals to generate n offset signals. The detecting circuit 110 transmits a change in the mutual inductance Cm, which is a relative value. Therefore, the offset device adds a programmable fixed value κ to the n digital signals to generate n offsets 201126401. When the programmable fixed value 1^ is 0 (1), the n offset signals are D(l)-K, D(2)-K, ··., D(n)-K. In other embodiments, the programmable fixed value scale may be a minimum value in 〇(1), 0(2), ..., 1)(11), that is, K=min{D(l), D( 2),...,D(n)}. In step S470, a frame buffer 27 is used to temporarily store the n sets of offset signals of the m groups by temporarily storing the offset device; and in step S480, the target determining device is used according to the claws. The change of the sTl number is offset, thereby determining whether there is a ground conductor or a finger touching the capacitive touch panel. It can be seen from the foregoing description that the present invention uses a differential subtraction architecture at the front end of the analog circuit to detect the difference between all adjacent two conductor lines in the first direction to reduce common noise (C〇mm〇n N〇ise), and improve the signal noise ratio (SNR), thereby improving the accuracy of the contact point coordinates. At the same time, according to the technique of the present invention, the spacing between adjacent conductor lines in the first direction can be reduced, and there is no need to worry that when the conductor lines are too close, the two conductor lines are simultaneously touched, and at the same time, signals are generated on the two conductor lines. This causes the signal to be subtracted from each other, thus improving the resolution of the capacitive touch panel conductor lines. As apparent from the above, the present invention is extremely useful in terms of its purpose, means, and efficacy, both of which are different from those of the prior art. It is to be noted that the various embodiments described above are only intended to be illustrative, and the scope of the invention is intended to be limited by the scope of the claims. [Simple description of the drawing] 13 201126401 Fig. 1 is a schematic diagram showing the driving of a conventional capacitive touch panel. 2 is a block diagram of a demodulation system for differentially detecting capacitive touch according to the present invention. Figure 3 is a schematic illustration of the operation of the demodulation device of the present invention. 4 is a flow chart of a method for demodulating a differential detection capacitive touch according to the present invention. [Description of main component symbols] Programmable gain amplifier 120 φ Offset device 140 Coordinate determination device 160 Subtractor 220 Analog to digital converter 240 Offset device 260 Coordinate determination device 280 Detection circuit 11 〇 analog to digital converter 130 Block buffer 150 detection circuit 21 〇 programmable gain amplifier 230 demodulation device 250 frame buffer 270 capacitive touch panel 290 steps S410~S480 14