M295768 八、新型說明： 【新型所屬之技術領域】 本創作係有關一冑具有t阻式壓力^測元件的 關於一種以電流模式偵測電阻式壓力二 件的指向裝置。 【先前技術】 壓力感測元件已經被廣泛地應用在筆記型電腦及其 他電子產品上。例如，壓力感測元件應用於筆記型電腦的 指向裝置，可取代滑鼠的功能，使用手指施予壓力在具有 壓力感測7L件的指向裝置上，可控制在上下左右方向的壓 力，以對應滑鼠游標的移動。而壓力感測元件可分為電阻 式與電谷式。已有的技術著重在以分壓原理彳貞測電阻式壓 力感測元件，或以電流偵測電容式壓力感測元件。 第一圖係電阻式壓力感測元件的示意圖，其係在一壓 力面板10下的不同方位上放置電阻RX+、RX— 'RY+及RY 一， 因應手指施予壓力在壓力面板1 〇，使電阻+ 及RY-受壓力影響而形變，致使其電阻值改變。第二圖係 電阻式壓力感測元件受力座標的示意圖。將壓力感測元件 施予壓力的方向定為X軸、Y軸及2軸。根據X轴及Y軸 的方向’分別放置電阻RX+、RX—、RY + &RY-，以偵測在X 轴、Y軸及Z軸施予壓力的數值。當施予x+方向的壓力於 壓力感測元件時，電阻RX+電阻值增加且RX—電阻值減少； 當施予Z-方向的壓力於壓力感測元件時，電阻RX+、RX 一、 RY+及RY-的電阻值同時增加。 M295768 目前此類型的指向裝置主要分成四線式及六線式的 指向裝置，以分壓原理設計。第三圖係習知的四線式的指 向裝置20的電路圖。一參考電阻22連接在一壓力感測元 件23與一電源Vs之間，壓力感測元件23包括電阻rx+、 RX-、RY+及RY-，電阻RX+及RY+—端連接參考電阻22， 電阻RX-及RY-之一端接地。電阻RX+、RX-、RY+及RY一的 電阻值必須相等，因此須以精密電阻作補償。運算放大器 24的輸入端24a連接在電阻RX+及RX-之間，運算放大器 26的輸入端26a連接在電阻RY+及RY-之間，運算放大器 28的輸入端28a連接在電阻RX+及RY+之間。運算放大器 24、26及28的輸入端24b、26b及28b連接一參考電壓 Vdac經電阻30及32分壓後的電壓，俾由參考電壓vdac 輸入不同的電壓值，以偵測X軸、Y轴及Z軸的壓力值。 一電阻34串接一電容36後與電阻32並聯，電容36連接 在一電晶體38的汲極與源極之間，電晶體38的閘極連接 一控制訊號。以偵測X軸為例，參考電壓Vdac輪入一電 壓值，使運算放大器24動作，偵測電阻1^+及Rx—的分壓 結果。在開始偵測X轴壓力時，計數器（圖中未示）重置狀 態且電晶體38開路，此時運算放大器24的輸入端24b電 壓隨電容36充電而上升，當運算放大器24轉態時，停止 計數器的計數，其數值即為偵測在X軸方向上的壓力 同理，可由相同的偵測方式偵測γ軸及2軸方向上的壓力 值。 第四圖係習知的六線式的指向裝置4〇的電路圖，— 參考電阻42連接在一壓力感測元件43與一電源ZM之間， 壓力感測元件43包括電阻RX+、RX-、以+及RY二電阻 6 M295768 連接電阻RX+、RY-及RY+，電源χρ、χΜ、γρ及γΜ分別連 接電阻 RX+、RX-、RY+及 RY—，電阻 RX+、Rx—、RY+及 RY— 的電阻值必須相等，因此須以精密電阻作補償。運算放大 态44的輸入端44a連接在電阻rx+及Rx—之間，另一輸入 44b連接一參考電壓Vdac經電阻仙及48分壓後的電 壓，俾由參考電壓Vdac提供一位準。參考電壓vdac係經 過補償的電壓，並利用分壓原理偵測X軸、γ軸及Z軸的 壓力值。以偵測X軸為例，電源ΖΜ、γρ及γΜ不給任何電 位，電源ΧΡ提供高電位，電源ΧΜ提供零電位，使運算放 大器44的輸入端44a在未受壓力的電位為（χρ+χΜ)/2。而 X軸在受壓力影響下，電阻RX+及RX-隨之變動，六線式的 指向裝置40即針對分壓比例判斷施加的壓力值，經由運 算放大器44將分壓的電壓放大，再由數位對類比轉換器 50將分壓值轉換為數位值。同理，在偵測Y軸壓力時，電 源ΖΜ、XP及XM不給任何電位，電源YP提供高電位，電 源YM提供零電位，使運算放大器44的輸入端44a在未受 壓力的電位為（YP+YM)/2 ;在偵測Z軸壓力時，電源YP及 YM不給任何電位，電源ZM提供高電位，電源XP及XM提 供零電位，使運算放大器44的輸入端44a在未受壓力的 電位為（XP+ZM)/2。 在此類傳統的指向裝置中，其壓力感測元件係以分壓 原理偵測壓力值，因此，在四線式或六線式的指向裝置 中，壓力感測元件所使用的參考電阻必須是精密電阻，且 各個偵測電阻RX+、RX-、RY+及RY-必須相等’但是在電 阻的製程上會產生飄移，通常需要額外串接電阻作補償， 使電阻RX+、RX-、RY+及RY-的電阻值相等。因此，一種 7 M295768 新的指向裝置，乃為所冀。 【新型内容】 本創作的主要目的’在於提出一種以電流模式债測電 • 阻式壓力感測元件的指向裝置，該壓力感測元件的電阻不 需使用精密電阻，以降低成本。 根據本創作，一種以電流模式偵測電阻式壓力感測元 件的指向裝置包括一電流源供應一電流；多組電阻因應受 ⑩ 壓而改變電阻值，該多組電阻被選擇性地連接該電流了二 未受壓時產生一參考電壓，在受壓時產生一差動電壓；一 差動訊號彳貞測器彳貞測该差動電壓產生一差動訊號；以及— 類比至數位轉換器轉換該差動訊號成一數位訊號。 【實施方式】 第五圖係本創作的系統方塊圖，本系統包括微控制器 52、SRAM54、ROM56、數位方塊58及以電流模式偵測 # 壓力感測元件的指向裝置60，微控制器52、SRAM54及 ROM56與電流模式偵測壓力感測元件的指向裝置6〇之間 以數位方塊58作為介面。 第六圖係以電流模式偵測壓力感測元件的指向裝置 • 60的功能方塊圖，包括一壓力感測元件61，其具有電阻 RX+、RX-、RY+及 RY·，分別代表 χ+、χ_、γ+及 γ_方向。 電阻RX+兩端為Χ1+及Χ2+，電阻rx_兩端為XI-及Χ2-, 電阻RY+兩端為Y1+及Y2+，電阻ry_兩端為Yi-及Y2-。 在未以手指施予壓力時，電陡rX+、rX…RY+及RY-的 M295768 電阻值大約相等。一多工器62，其輸入端連接電阻RX+、 RX-、RY+及RY-，以選擇要彳貞測的電阻。一電流源64， 連接多工器62的輸出，以提供電流！流至被選擇的電阻 RX+、RX-、RY+及RY-。電流源64控制電流I的變化， 俾在壓力感測元件61未受壓時，控制電流I流經電阻 RX+、RX-、RY+及RY-產生一電壓Vs。一差動訊號偵測 器66的輸入端連接多工器62的輸出，以偵測電阻兩端的 端電壓(V1-V2)，將端電壓（V1-V2)減去電壓Vs以得到差 動電壓Δν。一補償器68與一放大器70連接差動訊號偵 測器66的輸出，以分別補償及放大差動電壓Δν。一類比 對數位轉換器72連接放大器70的輸出端，俾將放大器7〇 輸出的類比^FI5虎轉換為數位訊號’並藉由數位方塊5 8交 由微控制器52處理。以電流模式偵測電阻式壓力感測元 件的指向裝置60在整合的技術上，可與電容式觸控板的 控制1C整合。第七圖顯示差動訊號偵測器66的内部組 成，包含一電壓轉換器6602及一電壓對電流轉換器 6604，電壓轉換器6602可以使用例如電壓位務器，其係 在壓力感測元件61未受壓時，調整壓力感測元件61的電 阻壓差至電壓Vs，電壓對電流轉換器6604係轉換該差動 電壓成一電流訊號，可以使用例如傳導放大器來實現。 第八圖係本創作偵測X軸方向的壓力值時的等效電 路。多工器62選擇連接電阻RX+的兩端χΐ+及X2+輸入， 電流源64提供電流I，在未施予壓力時，電流源64的電 流I使電阻RX+產生一電壓Vs，電流源64由電流鏡電路 或其他電路產生。電流源64具有多種變化，例如16* 16 種變化，其可調變電流I，俾在壓力感測元件61未受壓時， 9 M295768 控制電流I流經電阻RX+、RX-、RY+及RY_產生電壓VS。 電流源64藉由電路的切換加減調變電流I的變化，因此， 對於電阻RX+、RX-、RY+及RY-的製程飄移不敏感，不 影響以電流模式彳貞測壓力感測元件的指向裝置60的準確 度。電流源64藉由差動訊號偵測器66偵測電阻RX+的端 電壓(V1-V2)，'俾在未施予壓力時，調變電流I使電阻rX+ 的端電壓(V1-V2)等於Vs，及調整電壓VI及V2的壓差。 在以手指施予壓力時，差動訊號偵測器66偵測電壓VI 及V2的壓差，將電壓vi及V2的壓差減去電壓Vs以得 到差動電壓Δν，並以放大器70將差動電壓放大。補 償器68對差動電壓Δν作精密的補償，由於電流補償控 制較電壓補償控制不容易受雜訊影響，因此，補償器68 是以電流方式控制，再者，具有電路裝置設計容易的優 點。再經由類比對數位轉換器72將電流值轉換為數位訊 號。 根據第八圖’以電流模式偵測壓力感測元件的指向裝 置60在未施予壓力時，由電流源64提供電流I，俾使Χ1 + 及Χ2+兩端的電壓vi及V2的壓差為Vs，且固定電流在 Is。在施予壓力時，電阻rx+因壓力產生形變，其電阻值 隨之改變，因此，電壓VI及V2的壓差隨電阻RX+的電 阻值改變’指向裝置60藉由差動訊號偵測器66偵測電壓 VI及V2的壓差，並將壓差減去電壓νδ得到差動電壓△ V。由於電流源64將電流I固定為is，因此偵測差動電壓 △ V可知電阻RX+的變化量ΔΙι，本創作的工作原理，即 是配合上述電流原理及電阻rX+、RX-、RY+及RY_的偵 測可偵測壓力的變化。偵測χ軸係根據電阻RX+及 M295768 白勺變^ 彳貞測Y軸係根據電阻RY+及RY-的變化，偵測Z 由係根據電阻RX+、RX-、RY+及RY-的變化。 第九圖係本創作偵測電阻端電壓的直流準彳立六音 圖’根據電流源64調整電流〗，在電阻未受壓力而形變時; ^電壓V1約為216V，電壓V2約為ι ΐ6ν，根據原電阻 值所債測的電壓準位8〇,其壓差八為V1_v2，即M295768 VIII. New Description: [New Technology Field] This creation is about a pointing device with a resistive pressure sensor with a current mode. [Prior Art] Pressure sensing elements have been widely used in notebook computers and other electronic products. For example, the pressure sensing element is applied to the pointing device of the notebook computer, and can replace the function of the mouse. The pressure is applied by the finger on the pointing device with the pressure sensing 7L, and the pressure in the up, down, left, and right directions can be controlled to correspond. The movement of the mouse cursor. The pressure sensing components can be divided into a resistive type and an electric valley type. Prior art techniques have focused on measuring resistive pressure sensing components on a voltage division principle or as capacitive current sensing capacitive sensing components. The first figure is a schematic diagram of a resistive pressure sensing element placed with resistors RX+, RX-'RY+ and RY in different orientations under a pressure panel 10, in response to a finger pressure applied to the pressure panel 1 + and RY- are deformed by the influence of pressure, causing their resistance values to change. The second figure is a schematic diagram of the force coordinates of the resistive pressure sensing element. The direction in which the pressure sensing element is applied to the pressure is defined as the X-axis, the Y-axis, and the 2-axis. The resistors RX+, RX-, RY + & RY- are placed in the direction of the X-axis and the Y-axis, respectively, to detect the values of the pressure applied to the X-axis, the Y-axis, and the Z-axis. When the pressure in the x+ direction is applied to the pressure sensing element, the resistance RX+ resistance value increases and the RX—resistance value decreases; when the pressure in the Z-direction is applied to the pressure sensing element, the resistances RX+, RX1, RY+, and RY - The resistance value increases at the same time. M295768 At present, this type of pointing device is mainly divided into four-wire and six-wire pointing devices, which are designed on the principle of partial pressure. The third figure is a circuit diagram of a conventional four-wire pointing device 20. A reference resistor 22 is connected between a pressure sensing element 23 and a power source Vs. The pressure sensing element 23 includes resistors rx+, RX-, RY+, and RY-. The resistors RX+ and RY+ are connected to a reference resistor 22, and the resistor RX- And one of the RY- terminals is grounded. The resistance values of resistors RX+, RX-, RY+, and RY must be equal, so they must be compensated with precision resistors. The input terminal 24a of the operational amplifier 24 is connected between the resistors RX+ and RX-, the input terminal 26a of the operational amplifier 26 is connected between the resistors RY+ and RY-, and the input terminal 28a of the operational amplifier 28 is connected between the resistors RX+ and RY+. The input terminals 24b, 26b and 28b of the operational amplifiers 24, 26 and 28 are connected to a voltage divided by the reference voltage Vdac via the resistors 30 and 32, and the different voltage values are input by the reference voltage vdac to detect the X-axis and the Y-axis. And the pressure value of the Z axis. A resistor 34 is connected in series with a capacitor 36 and connected in parallel with a resistor 32. The capacitor 36 is connected between the drain and the source of a transistor 38. The gate of the transistor 38 is connected to a control signal. Taking the detection of the X-axis as an example, the reference voltage Vdac is wheeled with a voltage value to cause the operational amplifier 24 to operate to detect the voltage division result of the resistors 1^+ and Rx. When the X-axis pressure is detected, the counter (not shown) is reset and the transistor 38 is open. At this time, the voltage of the input terminal 24b of the operational amplifier 24 rises as the capacitor 36 is charged. When the operational amplifier 24 is turned, Stop the counting of the counter. The value is the same as the pressure in the X-axis direction. The same detection method can be used to detect the pressure values in the γ-axis and 2-axis directions. The fourth figure is a circuit diagram of a conventional six-wire pointing device, that is, a reference resistor 42 is connected between a pressure sensing element 43 and a power source ZM, and the pressure sensing element 43 includes resistors RX+, RX-, + and RY two resistors 6 M295768 connect the resistors RX+, RY- and RY+, the power supplies χρ, χΜ, γρ and γΜ are connected to the resistors RX+, RX-, RY+ and RY_, and the resistance values of the resistors RX+, Rx-, RY+ and RY- Must be equal, so they must be compensated with precision resistors. The input terminal 44a of the operational amplification state 44 is connected between the resistors rx+ and Rx-, and the other input 44b is connected to a reference voltage Vdac via a resistor and a voltage divided by 48, and is supplied with a reference voltage Vdac. The reference voltage vdac is the compensated voltage and uses the voltage division principle to detect the pressure values of the X-axis, γ-axis, and Z-axis. Taking the detection of the X-axis as an example, the power supply ΖΜ, γρ, and γΜ do not give any potential, the power supply ΧΡ provides a high potential, and the power supply ΧΜ provides a zero potential, so that the input terminal 44a of the operational amplifier 44 is at an unstressed potential (χρ+χΜ). )/2. When the X-axis is under the influence of the pressure, the resistances RX+ and RX- fluctuate accordingly, and the six-wire pointing device 40 determines the applied pressure value for the partial pressure ratio, and amplifies the divided voltage via the operational amplifier 44, and then digitizes The analog converter 50 converts the divided value into a digital value. Similarly, when detecting the Y-axis pressure, the power supply XP, XP and XM do not give any potential, the power supply YP provides a high potential, and the power supply YM provides a zero potential, so that the input terminal 44a of the operational amplifier 44 is at an unstressed potential ( YP+YM)/2; when detecting the Z-axis pressure, the power supplies YP and YM do not give any potential, the power supply ZM provides a high potential, and the power supplies XP and XM provide a zero potential, so that the input terminal 44a of the operational amplifier 44 is under no pressure. The potential is (XP+ZM)/2. In such a conventional pointing device, the pressure sensing element detects the pressure value by the principle of partial pressure. Therefore, in the four-wire or six-wire pointing device, the reference resistance used by the pressure sensing element must be Precision resistors, and each of the sense resistors RX+, RX-, RY+, and RY- must be equal 'but drifting occurs in the resistor process, usually requiring additional series resistors to compensate, making resistors RX+, RX-, RY+, and RY- The resistance values are equal. Therefore, a new 7 M295768 pointing device is what it is. [New content] The main purpose of this creation is to propose a pointing device for measuring the resistance of a current mode in a current mode. The resistance of the pressure sensing element does not require the use of a precision resistor to reduce the cost. According to the present invention, a pointing device for detecting a resistive pressure sensing element in a current mode includes a current source for supplying a current; a plurality of sets of resistors are required to be subjected to a voltage change of 10, and the plurality of resistors are selectively connected to the current a reference voltage is generated when the two are not pressed, and a differential voltage is generated when the voltage is pressed; a differential signal detector detects the differential voltage to generate a differential signal; and - analog to digital converter conversion The differential signal is a digital signal. [Embodiment] The fifth figure is a system block diagram of the present invention. The system includes a microcontroller 52, an SRAM 54, a ROM 56, a digital block 58 and a pointing device 60 for detecting a # pressure sensing element by a current mode, and the microcontroller 52 The SRAM 54 and the ROM 56 are connected to the pointing device 6A of the current mode detecting pressure sensing element by a digital block 58 as an interface. The sixth diagram is a functional block diagram of the pointing device 60 of the current mode detecting pressure sensing element, including a pressure sensing element 61 having resistances RX+, RX-, RY+, and RY·, respectively representing χ+, χ_ , γ+ and γ_ directions. The ends of the resistor RX+ are Χ1+ and Χ2+, the ends of the resistor rx_ are XI- and Χ2-, the ends of the resistor RY+ are Y1+ and Y2+, and the ends of the resistor ry_ are Yi- and Y2-. When the pressure is not applied by the fingers, the M295768 resistance values of the electric steepness rX+, rX...RY+ and RY- are approximately equal. A multiplexer 62 has its input terminals connected to resistors RX+, RX-, RY+ and RY- to select the resistance to be measured. A current source 64, connected to the output of the multiplexer 62 to provide current! Flows to the selected resistors RX+, RX-, RY+, and RY-. Current source 64 controls the change in current I. When voltage sensing element 61 is uncompressed, control current I flows through resistors RX+, RX-, RY+, and RY- to produce a voltage Vs. The input of a differential signal detector 66 is connected to the output of the multiplexer 62 to detect the terminal voltage (V1-V2) across the resistor, and the terminal voltage (V1-V2) is subtracted from the voltage Vs to obtain a differential voltage. Δν. A compensator 68 is coupled to an amplifier 70 for outputting the differential signal detector 66 to separately compensate and amplify the differential voltage Δν. A type of analog to digital converter 72 is coupled to the output of amplifier 70, which converts the analog output of amplifier 7A into a digital signal' and is processed by microcontroller 52 via digital block 58. The pointing device 60 for detecting the resistive pressure sensing element in current mode can be integrated with the control 1C of the capacitive touch panel in an integrated technique. The seventh diagram shows the internal components of the differential signal detector 66, including a voltage converter 6602 and a voltage-to-current converter 6604. The voltage converter 6602 can use, for example, a voltage server, which is coupled to the pressure sensing element 61. When not pressurized, the resistance voltage difference of the pressure sensing element 61 is adjusted to a voltage Vs, and the voltage to current converter 6604 converts the differential voltage into a current signal, which can be implemented using, for example, a conduction amplifier. The eighth figure is the equivalent circuit when the creation detects the pressure value in the X-axis direction. The multiplexer 62 selects both ends χΐ+ and X2+ inputs of the connection resistor RX+, and the current source 64 provides a current I. When no pressure is applied, the current I of the current source 64 causes the resistor RX+ to generate a voltage Vs, and the current source 64 is current. Mirror circuits or other circuits are produced. The current source 64 has a variety of variations, such as 16*16 variations, the adjustable variable current I, 俾 when the pressure sensing element 61 is uncompressed, 9 M295768 control current I flows through the resistors RX+, RX-, RY+, and RY_ The voltage VS is generated. The current source 64 is added or subtracted by the switching of the circuit to change the modulation current I. Therefore, it is insensitive to the process drift of the resistors RX+, RX-, RY+, and RY-, and does not affect the pointing device of the pressure sensing element in the current mode. 60 accuracy. The current source 64 detects the terminal voltage (V1-V2) of the resistor RX+ by the differential signal detector 66. 'When the pressure is not applied, the current I is modulated so that the terminal voltage (V1-V2) of the resistor rX+ is equal to Vs, and adjust the voltage difference between voltage VI and V2. When the pressure is applied by the finger, the differential signal detector 66 detects the voltage difference between the voltages VI and V2, subtracts the voltage difference Vs from the voltage difference of the voltages vi and V2 to obtain the differential voltage Δν, and the difference is obtained by the amplifier 70. Dynamic voltage amplification. The compensator 68 precisely compensates the differential voltage Δν. Since the current compensation control is less susceptible to noise than the voltage compensation control, the compensator 68 is controlled by current, and further has the advantage that the circuit device design is easy. The current value is then converted to a digital signal via an analog to digital converter 72. According to the eighth figure, when the pointing device 60 for detecting the pressure sensing element in the current mode does not apply the pressure, the current I is supplied from the current source 64, so that the voltage difference between the voltages vi and V2 across the Χ1 + and Χ 2+ is Vs And the fixed current is in Is. When the pressure is applied, the resistance rx+ is deformed by the pressure, and the resistance value thereof changes accordingly. Therefore, the voltage difference between the voltages VI and V2 changes with the resistance value of the resistor RX+. The pointing device 60 detects by the differential signal detector 66. The voltage difference between voltages VI and V2 is measured, and the voltage difference νδ is subtracted from the voltage difference to obtain a differential voltage ΔV. Since the current source 64 fixes the current I to is, the differential voltage ΔV is detected to know the variation ΔΙι of the resistor RX+. The working principle of the present invention is to cooperate with the current principle and the resistors rX+, RX-, RY+ and RY_. The detection detects changes in pressure. The detection axis is based on the changes of the resistors RX+ and M295768. The Y-axis is based on the changes of the resistors RY+ and RY- to detect changes in the Z-based system based on the resistances RX+, RX-, RY+ and RY-. The ninth picture is the DC standard 六 six-tone diagram of the detection of the resistance terminal voltage 'adjust current according to the current source 64〗, when the resistance is not deformed by the pressure; ^ voltage V1 is about 216V, voltage V2 is about ι ΐ6ν According to the original resistance value, the voltage level measured by the debt is 8〇, and the pressure difference is 8 V1_v2, that is,
a==(V1-V2)=1V (EQ-1) 〇 …在電阻雙壓力形變而增加時，電壓VI大於2.16V， 電壓V2小於1.16V ’根據電阻值增加所偵測的電壓準位 82，其壓差B為V1-V2，即 (EQ-2)，a==(V1-V2)=1V (EQ-1) 〇...When the resistance double pressure is deformed, the voltage VI is greater than 2.16V, and the voltage V2 is less than 1.16V. 'The detected voltage level is 82 according to the resistance value. , the pressure difference B is V1-V2, ie (EQ-2),
B=(V1-V2)-1V+ARxIB=(V1-V2)-1V+ARxI
其中，△R代表電阻的變化量。在電阻受壓力形變而 減少時，電壓VI小於2.16V，電壓V2大於116V，根據 電阻值減少所偵測的電壓準位84，其壓差c為V1-V2， 即 C=(Vl-V2)=lV-ARxI (EQ.3), 其中，AR代表電阻的變化量。依照第七圖以镇測變 化量ΔΙΙ，並使用本創作的動作分析的結$，可_施加 壓力的方向及力量。本創作的動作包括在電阻RX+的電阻 值增加，電阻RX-的電阻值滅少，代表受力方向為χ+。 11 M295768 在電阻RX+的電阻值減少，電阻Rx_的電阻值增加，代表 受力方向為X-。在電阻RY+的電阻值增加，電阻RY_的電 阻值減少，代表受力方向為Y+。在電阻RY+的電阻值減 少’電阻RX-的電阻值增加，代表受力方向為γ_。在電阻 RX+、RX-、RY+及RY-的電阻值同時增加時，代表受力方 向為Z-。在各方向的電阻為相互對稱性電阻。 本創作以電流模式偵測壓力感測元件的指向裝置的 應用電路簡單，且由於主要係以電流方式控制且偵測差動 訊號，因此較習知的指向裝置具有更佳的抗雜訊能力。再 者，本創作係使用電流模式偵測壓力，不需使用精準的參 考電阻及額外的運算放大器，而且習知的指向裝置，係應 用分壓原理，對於電阻製程的飄移極為敏感，是習知技術 的一大缺點’而本創作以電流模式彳貞測歷力’對於電阻樂』 程的飄移不敏感，有極大的改進。 以上對於本創作之較佳實施例所作的敘述係為閣明 之目的，而無意限定本創作精確地為所揭露的形式，基於 以上的教導或從本創作的實施例學習而作修改或變彳匕I 可能的，實施例係為解說本創作的原理以及讓熟習該項技 術者以各種實施例利用本創作在實際應用上而選擇及秦欠 述，本創作的技術思想企圖由以下的申請專利範圍及其^勺 等來決定。 以 【圖式簡單說明】 對於熟習本技藝之人士而言，從以下所作的詳細敎 配合伴隨的圖式，本創作將能夠更清楚地被瞭解，其上^ 12 M295768 及其他目的及優點將會變得更明顯，其中·· 第圖係電阻式壓力感測元件的示意圖； 第=圖係電阻式壓力感測元件受力座標的示意圖； 第二圖係習知的四線式的指向裝置的電路圖； 弟四圖係習知的六線式的指向裝置的電路圖； 第五圖係本創作的系統方塊圖； 第六圖係本創作以電流模式偵測電阻式壓力感測元 件的指向裝置的功能方塊圖； 第七圖顯示差動訊號偵測器66的内部組成； 弟八圖係本創作彳貞測X軸方向的壓力值的等效電 路；以及 第九圖係本創作债測電阻端電壓的直流準位示意圖。 【主要元件符號說明】 10 壓力面板 20 四線式的指向裝置 22 參考電阻 23 壓力感測元件 24 運算放大器 24a 輸入端 24b 輸入端 26 運算放大器 26a 輸入端 26b 輸入端 28 運算放大器 13 M295768 28a 輸入端 28b 輸入端 30 電阻 32 電阻 34 電阻 36 電容 38 電晶體 40 六線式的指向裝置 42 參考電阻 43 壓力感測元件 44 運算放大器 44a 輸入端 44b 輸入端 50 類比至數位轉換器 52 微控制器Where ΔR represents the amount of change in resistance. When the resistance is reduced by pressure deformation, the voltage VI is less than 2.16V, the voltage V2 is greater than 116V, and the detected voltage level 84 is reduced according to the resistance value, and the pressure difference c is V1-V2, that is, C=(Vl-V2). = lV - ARxI (EQ.3), where AR represents the amount of change in resistance. According to the seventh figure, the change amount ΔΙΙ is measured and the knot of the action analysis of the present invention is used, and the direction and force of the pressure can be applied. The action of this creation includes the increase of the resistance value of the resistor RX+, and the resistance value of the resistor RX- is less, indicating that the direction of the force is χ+. 11 M295768 The resistance value of the resistor RX+ decreases, and the resistance value of the resistor Rx_ increases, indicating that the force direction is X-. When the resistance value of the resistor RY+ increases, the resistance value of the resistor RY_ decreases, indicating that the force direction is Y+. The resistance value of the resistor RY+ decreases. The resistance value of the resistor RX- increases, indicating that the force direction is γ_. When the resistance values of the resistors RX+, RX-, RY+, and RY- increase simultaneously, the force direction is Z-. The resistance in each direction is a mutual symmetrical resistance. The application circuit of the pointing device for detecting the pressure sensing element in the current mode is simple, and since the main method is current mode control and detecting the differential signal, the conventional pointing device has better anti-noise capability. Furthermore, this creation uses current mode to detect pressure without the use of precise reference resistors and additional operational amplifiers, and the conventional pointing device is based on the principle of voltage division, which is extremely sensitive to the drift of the resistance process. A major shortcoming of the technology' and the creation of the current mode is not sensitive to the drift of the resistance music process, and there is a great improvement. The above description of the preferred embodiment of the present invention is for the purpose of the disclosure, and is not intended to limit the present invention precisely to the disclosed form, and is modified or changed based on the above teachings or learning from the embodiments of the present invention. I. The possible embodiments are to explain the principle of the present invention and to let the skilled person use the present invention in various embodiments to select and confuse the actual application. The technical idea of the present creation is attempted by the following patent application scope. And its spoon and so on. For a person familiar with the art, this creation will be more clearly understood from the following detailed descriptions, along with the accompanying drawings, on which the 12 M295768 and other purposes and advantages will be It becomes more obvious, wherein the figure is a schematic diagram of a resistive pressure sensing element; the second figure is a schematic diagram of the force-bearing pressure sensing element; the second figure is a conventional four-wire pointing device Circuit diagram; the fourth diagram of the conventional six-wire pointing device; the fifth diagram is the system block diagram of the creation; the sixth diagram is the current mode to detect the pointing device of the resistive pressure sensing element The functional block diagram; the seventh figure shows the internal composition of the differential signal detector 66; the eighth figure is the equivalent circuit of the pressure value in the X-axis direction of the creation; and the ninth figure is the debt-testing resistance end of the creation Schematic diagram of the DC level of the voltage. [Main component symbol description] 10 Pressure panel 20 Four-wire pointing device 22 Reference resistor 23 Pressure sensing component 24 Operational amplifier 24a Input terminal 24b Input terminal 26 Operational amplifier 26a Input terminal 26b Input terminal 28 Operational amplifier 13 M295768 28a Input terminal 28b input 30 resistor 32 resistor 34 resistor 36 capacitor 38 transistor 40 six-wire pointing device 42 reference resistor 43 pressure sensing element 44
54 SRAM54 SRAM
56 ROM 58 數位方塊 60 以電流模式偵測壓力感測元件的指向裝置 61 壓力感測元件 62 多工器 64 電流源 66 差動訊號偵測器 6602 電壓轉換器 6604 電壓對電流轉換器 68 補償器 14 M295768 70 放大器 72 類比至數位轉換器 74 微控制器 80 原電阻值所偵測的電壓準位 82 電阻值增加所偵測的電壓準位 84 電阻值減少所偵測的電壓準位56 ROM 58 Digital Block 60 Pointing Device for Detecting Pressure Sensing Element in Current Mode 61 Pressure Sensing Element 62 Multiplexer 64 Current Source 66 Differential Signal Detector 6602 Voltage Converter 6604 Voltage to Current Converter 68 Compensator 14 M295768 70 Amplifier 72 Analog to Digital Converter 74 Microcontroller 80 Voltage Level Detected by Original Resistance Value 82 Resistance Value Increased Detected Voltage Level 84 Resistance Value Reduces Detected Voltage Level
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