1358672 九、發明說明： 【發明所屬之技術領域】 本發明係關於一種電容式指紋感應器及其面板，特別是 關於一種使用複數個電晶體之電容式指紋感應器及其面 板。 【先前技術】 指紋感應器為一種用於辨認手指紋樣式及提供可靠度之 個人身份識別的感應器。該指紋感應器也廣泛地使用於可 攜式產品，例如手機、筆記型電腦，用以確保個人保密資 料的安全性。 圖1A和1B顯示指紋感應器之等效電路。大體而言，指紋 感應器可以被實現於一晶片内，在圖1A的編號13代表一保 護層，其作為電容<^之介電層。若該指紋感應器被嵌入於 一影像面板在圖1A的編號u代表一 IT〇層，且編號13代 表玻璃和薄膜，例如彩色濾光片、偏光板等。以下之敘述 以嵌入於影像面板之指紋感應器為例。在圖丨Α，一玻璃 13、一上金屬層丨丨及一基板12以串聯方式結合，且該玻璃 13疋使用者手指可以碰觸的地方。通常一電容&存在於玻 璃13内，且一電容Q存在於上金屬層11和基板12之間。在 圖1B，使用者手指的表面可分為凸部〗々和凹部15。該凹部 15和該玻璃13有一個距離七，而該玻璃13之厚度為七。基 於該結構，一額外電容C2存在於該使用者手指的凹部及該 玻璃13之表面。該凸部電容值係與ci相關，該凹部電容 值係與Cl//C2相關，而C1和C1//C2可用以下方式表示： 124409.doc 1358672 c,=t，且 Ci〃C2=^^z 通常該凸部電容值遠大於該凹部電容值。 為了感應使用者手指，一讀出電路應可分 f咏凸部電容 及凹部電容值。然而，其並不容易得到所需之準確度， 因為-些環境上的因素，例如雜訊或串音都 : 【發明内容】 、。心。果。 本發明之電容式指紋感應器之一實施例包含—感應單元 及一控制電路。該感應單元包含-指紋電容、—參考電= 及一第一電晶體。該指紋電容之電容值為—凹部電容值^ 或一凸部電容值且G<cw。該參考電容端連接 =紋電容’另一端連接至—觸發訊號，其中該觸發訊 说僅在-預充電階段啓動，且該第—電晶體包 含一閘極端、一輸入端及-輪出端，*中該閘極端由一掃 7所控制，且該輸人端連接至該指紋電容，該輸出端連 接至讀出線。該控制電路包含一第二電晶體、一運算 放大益、-第三電晶體及一多工器。該第二電晶體包含一 閘極端、-輸入端及一_，其中該閉極端由一第一重 置線所控制，且該輸人端連接至該讀出線。該運算放大器 之一輸入端連接至該第二電晶體之輸出端。該第三電晶體 包含一閘極端一輸人端及1出端，其中該閘極端由-第-重置線所控制，該輸入端和輪出端分別連接至該運算 放大益之輸入端和輸出端。該多工器連接至該運算放大器 124409.doc 1358672 之另一輸入端，其中該多工器之輸入端連接至一第一電壓 VA和一閥值電壓vth。 本發明之電容式指紋感應器之另一實施例包含一感應單 元及一控制電路。該感應單元包含一指紋電容、一參考電 谷5及一弟一電晶體。該指紋電容之電谷值為—凹部電容 值C/v或一凸部電容值，且G。該參考電容cs之一端 連接至該指紋電容，另一端連接至一觸發訊號，其中該觸 發訊號僅在一預充電階段啓動，且Cs< 。該第—電晶 體用於在一掃描線週期控制該指紋電容。該控制電路包含 一第二電晶體、.一比較器及一多工器。該第二電晶體用於 預充電該指紋電容及參考電容。該比較器之一輸入端連接 至該第二電晶。該多工器連接至該比較器之另一輸入端， 用於選擇性提供一第一電壓VA和一閥值電壓vth。 本發明之包含電容式指紋感應器之面板系統之一實施例 包含一具有複數個電容式指紋感應單元之主動式矩陣區 域、一掃描驅動器、一讀出電路及一影像處理電路。該掃 描驅動器用於控制連接至該電容式指紋感應器之掃描線。 該讀出電路用於接收該電容式指紋感應單元之資料且辨認 該指紋電容之種類。該影像處理電路連接至該讀出電路。 【實施方式】 圖2顯不本發明之面板之一具體實施例。該面板系統包含 一主動式矩陣區域25、一資料驅動器21、一掃描驅動器22、 一讀出電路23及一影像處理電路24。該主動式矩陣區域25 包含一電容式指紋感應器及/或複數個影像晝素。該電容式 -Ί- I24409.doc 1358672 指紋感應器具有複數個電容式指紋感應單元3 1，而每一個 電容式指紋感應單元3 1都可以選擇性地和一影像畫素共存 於一畫素單元。該資料驅動器21用於驅動資料。該掃描驅 動器22用於控制連接至該電容式指紋感應單元3丨之掃描 線。大體而言，當該電容式指紋感應單元31被操作時，連 接至該電容式指紋感應單元31之掃描線在整個操作過程被 啓動。該讀出電路23用於接收該電容式指紋感應單元31之 讀出線的類比訊號，且辨認該指紋電容3 1之型式，例如凹 部電容值〜或凸部電容值G。該影像處理電路24連接至該 讀出電路23。圖2之結構係以影像面板之嵌入式結構為例， 但熟悉該項技術者均可知悉圖2之結構可以被輕易轉換及 應用於一晶片内。 圖3顯示本發明之指紋感應器之一具體實施例。該讀出電 路23包含一控制電路38。電容式指紋感應單元31包含一第 一電晶體32、一參考電容Q及一指紋電容Cf，其電容值為 一凹部電容值^或—凸部電容值，且C/v<Cs<Cra。位於 該主動式矩陣區域25之同一列之第一電晶體32係由同—掃 描線所控制。該參考電容Cs之一端連接至該指紋電容，另 -端連接至-觸發訊號，其中該觸發訊號僅在—預充電階 段啓動°該第-電晶體32包含—閘極端…輸人端及一輸 出端，其中該閘極端由-掃描線所控制，且該輸人端連接 至該指紋電容，該輸出端連接至—讀出線，其中該讀出線 更連接至該控制電路38之一輸入端。 該控制電路38可為該讀出電路23之-部分，而另一部分 124409.doc -8- 1358672 61顯示於圖6。該控制電路38包含—第二電晶體％、一運算 放大W、一第三電晶體35及一多工器37。該第二電晶體 —^3 Μ極端、-輸人端及_輸出端，其中該閑極端由 第重置線Resetl所控制，且該輸入端連接至該讀出 線該運算放大器36之一輸入端連接至該第二電晶體Μ之 輸出端。第三電晶體35包含一閘極端、一輸入端及—輸 出端’其中該閉極端由一第二重置獻咖所控制，且該輸1358672 IX. Description of the Invention: The present invention relates to a capacitive fingerprint sensor and a panel thereof, and more particularly to a capacitive fingerprint sensor using a plurality of transistors and a panel thereof. [Prior Art] A fingerprint sensor is a sensor for recognizing a hand fingerprint pattern and providing personal identification for reliability. The fingerprint sensor is also widely used in portable products such as mobile phones and notebook computers to ensure the security of personal confidential information. 1A and 1B show an equivalent circuit of a fingerprint sensor. In general, the fingerprint sensor can be implemented in a wafer, reference numeral 13 in Figure 1A, which represents a protective layer that acts as a dielectric layer of capacitance < If the fingerprint sensor is embedded in an image panel, the number u in Fig. 1A represents an IT layer, and the number 13 represents a glass and a film, such as a color filter, a polarizing plate, and the like. The following description takes the fingerprint sensor embedded in the image panel as an example. In the figure, a glass 13, an upper metal layer, and a substrate 12 are joined in series, and the glass 13 is where the user's fingers can touch. Usually, a capacitor & is present in the glass 13, and a capacitor Q is present between the upper metal layer 11 and the substrate 12. In Fig. 1B, the surface of the user's finger can be divided into a convex portion and a concave portion 15. The recess 15 and the glass 13 have a distance of seven, and the glass 13 has a thickness of seven. Based on this configuration, an additional capacitor C2 is present on the recess of the user's finger and the surface of the glass 13. The convex capacitance value is related to ci, the concave capacitance value is related to Cl//C2, and C1 and C1//C2 can be expressed in the following manner: 124409.doc 1358672 c,=t, and Ci〃C2=^^ z Usually the convex capacitance value is much larger than the concave capacitance value. In order to sense the user's finger, a readout circuit should be able to divide the value of the convex capacitance and the concave capacitance. However, it is not easy to get the required accuracy, because some environmental factors, such as noise or crosstalk: [invention]. heart. fruit. One embodiment of the capacitive fingerprint sensor of the present invention includes a sensing unit and a control circuit. The sensing unit includes a fingerprint capacitor, a reference power, and a first transistor. The capacitance value of the fingerprint capacitor is - a concave capacitance value ^ or a convex capacitance value and G < cw. The reference capacitor terminal connection = the pattern capacitor 'the other end is connected to the - trigger signal, wherein the trigger signal is only activated in the pre-charge phase, and the first transistor includes a gate terminal, an input terminal, and a wheel terminal. * The gate terminal is controlled by a sweep 7, and the input terminal is connected to the fingerprint capacitor, and the output terminal is connected to the readout line. The control circuit includes a second transistor, an operational amplifier, a third transistor, and a multiplexer. The second transistor includes a gate terminal, an input terminal, and a _, wherein the closed terminal is controlled by a first reset line, and the input terminal is connected to the sense line. One of the operational amplifier inputs is coupled to the output of the second transistor. The third transistor includes a gate terminal, an input terminal and an output terminal, wherein the gate terminal is controlled by a -first reset line, and the input terminal and the wheel output terminal are respectively connected to the input terminal of the operation amplification and Output. The multiplexer is coupled to another input of the operational amplifier 124409.doc 1358672, wherein the input of the multiplexer is coupled to a first voltage VA and a threshold voltage vth. Another embodiment of the capacitive fingerprint sensor of the present invention includes a sensing unit and a control circuit. The sensing unit includes a fingerprint capacitor, a reference grid 5, and a transistor. The electric valley value of the fingerprint capacitor is a concave capacitance value C/v or a convex capacitance value, and G. One end of the reference capacitor cs is connected to the fingerprint capacitor, and the other end is connected to a trigger signal, wherein the trigger signal is only activated in a pre-charge phase, and Cs < The first electro-optic crystal is used to control the fingerprint capacitance during a scan line period. The control circuit includes a second transistor, a comparator and a multiplexer. The second transistor is used to precharge the fingerprint capacitor and the reference capacitor. An input of the comparator is coupled to the second transistor. The multiplexer is coupled to the other input of the comparator for selectively providing a first voltage VA and a threshold voltage vth. An embodiment of the panel system including the capacitive fingerprint sensor of the present invention comprises an active matrix region having a plurality of capacitive fingerprint sensing units, a scan driver, a readout circuit and an image processing circuit. The scan driver is used to control the scan lines connected to the capacitive fingerprint sensor. The readout circuit is configured to receive the data of the capacitive fingerprint sensing unit and identify the type of the fingerprint capacitance. The image processing circuit is coupled to the readout circuit. [Embodiment] Fig. 2 shows a specific embodiment of a panel of the present invention. The panel system includes an active matrix area 25, a data driver 21, a scan driver 22, a readout circuit 23, and an image processing circuit 24. The active matrix area 25 includes a capacitive fingerprint sensor and/or a plurality of image pixels. The capacitive type-I-24409.doc 1358672 fingerprint sensor has a plurality of capacitive fingerprint sensing units 31, and each of the capacitive fingerprint sensing units 31 can selectively coexist with an image pixel in a pixel unit. . The data drive 21 is used to drive data. The scan driver 22 is for controlling a scan line connected to the capacitive fingerprint sensing unit 3''. In general, when the capacitive fingerprint sensing unit 31 is operated, the scan line connected to the capacitive fingerprint sensing unit 31 is activated during the entire operation. The readout circuit 23 is configured to receive an analog signal of the readout line of the capacitive fingerprint sensing unit 31, and identify the pattern of the fingerprint capacitor 31, such as a recess capacitance value or a convex portion capacitance value G. The image processing circuit 24 is connected to the readout circuit 23. The structure of Fig. 2 is exemplified by the embedded structure of the image panel, but those skilled in the art can know that the structure of Fig. 2 can be easily converted and applied to a wafer. Figure 3 shows a specific embodiment of the fingerprint sensor of the present invention. The read circuit 23 includes a control circuit 38. The capacitive fingerprint sensing unit 31 comprises a first transistor 32, a reference capacitor Q and a fingerprint capacitor Cf, the capacitance value of which is a concave capacitance value or a convex capacitance value, and C/v < Cs < Cra. The first transistor 32 located in the same column of the active matrix region 25 is controlled by the same-scan line. One end of the reference capacitor Cs is connected to the fingerprint capacitor, and the other end is connected to the -trigger signal, wherein the trigger signal is only activated during the pre-charging phase. The first transistor 32 includes a gate terminal... an input terminal and an output. a terminal, wherein the gate terminal is controlled by a scan line, and the input end is connected to the fingerprint capacitor, the output terminal is connected to the readout line, wherein the readout line is further connected to one input end of the control circuit 38 . The control circuit 38 can be part of the readout circuit 23 and the other portion 124409.doc -8-1358672 61 is shown in FIG. The control circuit 38 includes a second transistor %, an operational amplifier W, a third transistor 35, and a multiplexer 37. The second transistor - the ?3 terminal, the input terminal and the _ output, wherein the idle terminal is controlled by the reset line Reset1, and the input terminal is connected to the read line and the input of the operational amplifier 36 The terminal is connected to the output end of the second transistor. The third transistor 35 includes a gate terminal, an input terminal, and an output terminal, wherein the closed terminal is controlled by a second resetting coffee, and the input
入端和輸出端連接至該運算放大器36之輸入端和輸出端。 ，多437連接至該運算放大器％之另一輸入端，其中該 夕工益37之輸入端連接至一第一電壓VA和一閥值電壓The input and output are coupled to the input and output of the operational amplifier 36. The multiple 437 is connected to the other input terminal of the operational amplifier, wherein the input of the Xiyiyi 37 is connected to a first voltage VA and a threshold voltage
Vth。 圖4顯示圖3電路之時序圖。大體而言，在同一列之指紋 電容共用同-個掃描机，其在該列所有指紋電容之整個 操作過程被啓動。-個週期的時序被分為—預充電階段（第 I1白丰又）轉換階段（第二階段）&一估算階段（第三階 段），且彼此未重疊。該第一重置線Resetl係被啓動於該預 充電階段和估算階段，該第二重置線細係被啓動於該預 充電階段和轉換階段。在估算階段時’讀出線選擇似循 序由V〇utl至Voutx傳輪資料至該影像處理電路24。在該預充 電階段時，該觸發訊號為低準位，且具有—脈波降幅叹。 圖5Α顯示在預充電階段，該指紋感應器之等效電路。在 預充電階段，該第二電晶體34及第三電晶體35被致能，且 該多工器37選擇VA’且VA等於VD。據此，儲存於節點ν 之電荷為（CF hCjxFX。 124409.doc 1358672 圖5B顯示在轉換階段，該指紋感應器之等效電路。在轉 換階段，第二電晶體34被關閉，第三電晶體35被致能，且 該多工器37選擇Vth。此時該觸發訊號轉為高準位，且該指 紋電容之電壓依據使用者手指被偵測到的部位即指紋凸 部或凹部，而改變其輸出為或Vth. Figure 4 shows a timing diagram of the circuit of Figure 3. In general, the fingerprint capacitors in the same column share the same scanner, which is activated during the entire operation of all fingerprint capacitors in the column. The timing of the -cycle is divided into a precharge phase (I1 White Plus) transition phase (second phase) & an estimation phase (third phase), and does not overlap each other. The first reset line Reset is initiated in the precharge phase and the estimation phase, and the second reset line is initiated in the precharge phase and the transition phase. In the estimation phase, the readout line is selected to sequentially route data from V〇utl to Voutx to the image processing circuit 24. During the pre-charging phase, the trigger signal is at a low level and has a pulse drop sigh. Figure 5 shows the equivalent circuit of the fingerprint sensor during the pre-charge phase. In the precharge phase, the second transistor 34 and the third transistor 35 are enabled, and the multiplexer 37 selects VA' and VA is equal to VD. Accordingly, the charge stored at node ν is (CF hCjxFX. 124409.doc 1358672. Figure 5B shows the equivalent circuit of the fingerprint sensor during the conversion phase. In the conversion phase, the second transistor 34 is turned off, the third transistor 35 is enabled, and the multiplexer 37 selects Vth. At this time, the trigger signal is turned to a high level, and the voltage of the fingerprint capacitor is changed according to the detected position of the user's finger, that is, the fingerprint convex portion or the concave portion. Its output is or
Ls+Cfr Cs+CpyLs+Cfr Cs+Cpy
圖5C顯示在估算階段，該指紋感應器之等效電路。在估 算階段，該第二電晶體34被致能，第三電晶體35被關閉， 且該夕工器3 7仍選擇Vth。此時該運算放大器36作為一比較 器的功能。若M + ^^xPT>Vth ,則Voutm+i顯示邏輯高位 準。反之，則顯示邏輯低位準。換言之，為區別指纟凸部 電容或…容，可設定為 Q + CFy Μ + 。因此，若該運算放大器36輸出邏輯低位準， 其代表該指紋感應器所接收之資料為一指紋凸部電容。反 之’則為一指紋凹部電容。Figure 5C shows the equivalent circuit of the fingerprint sensor during the estimation phase. In the estimation phase, the second transistor 34 is enabled, the third transistor 35 is turned off, and the day processor 37 still selects Vth. At this time, the operational amplifier 36 functions as a comparator. If M + ^^xPT > Vth , then Voutm+i displays a logic high level. Otherwise, the logic low level is displayed. In other words, to distinguish the finger capacitance or capacitance, it can be set to Q + CFy Μ + . Therefore, if the operational amplifier 36 outputs a logic low level, it represents that the data received by the fingerprint sensor is a fingerprint convex capacitor. The opposite is a fingerprint recess capacitance.
圖6顯示本發明之一具體實施例之讀出電路的一部分 63。§亥讀出電路的一部分63包含一多工器62，其由％叫 至V〇utx接受資料且再傳送至該影像處理電路24。。 本發明之技術内容及技術特點已揭示如上，然而熟悉本 項技術之人士仍可能基於本發明之教示及揭示而作種種不 月離本發明精神之替換及修飾。因此，本發明之保護範圍 應不限於實施例所揭示者，而應包括各種不背離本發明之 替換及修飾，並為以下之申請專利範圍所涵蓋。 【圖式簡單說明】 124409.doc -1& 1358672 圖1A和1B顯示指紋感應器之等效電路； 圖2顯示本發明之面板之一具體實施例； 圖3顯示本發明之指紋感應器之一具體實施例； 圖4顯示圖3電路之時序圖； 圖5A至5C顯示圖3電路之預充電階段、轉換階段及估算 階段；及 圖6顯示本發明之一具體實施例之一部分讀出電路。 【主要元件符號說明】 11 上金屬板 12 基板 13 保護層 14 指紋凸部 15 指故凹部 21 資料驅動器 22 掃描驅動器 23 讀出電路 24 影像處理電路 25 面板 31 電容式指紋感應單元 32 第一電晶體 指故電容 34 第一電晶體 35 第三電晶體 36 運算放大器 37 >工器 38 控制電路 62 輪出多工器 63 讀出電路的一部分 參考電容 124409.doc •11»Figure 6 shows a portion 63 of the readout circuitry of one embodiment of the present invention. A portion 63 of the readout circuitry includes a multiplexer 62 that accepts data from % to V〇utx and transmits it to the image processing circuitry 24. . The technical contents and technical features of the present invention have been disclosed as above, but those skilled in the art can still make various alternatives and modifications to the present invention based on the teachings and disclosures of the present invention. Therefore, the scope of the present invention should be construed as being limited by the scope of the appended claims. [Simple description of the drawings] 124409.doc -1& 1358672 Figs. 1A and 1B show an equivalent circuit of a fingerprint sensor; Fig. 2 shows a specific embodiment of the panel of the present invention; Fig. 3 shows one of the fingerprint sensors of the present invention 4 shows a timing diagram of the circuit of FIG. 3; FIGS. 5A to 5C show a precharge phase, a conversion phase, and an estimation phase of the circuit of FIG. 3; and FIG. 6 shows a partial readout circuit of one embodiment of the present invention. [Main component symbol description] 11 Upper metal plate 12 Substrate 13 Protective layer 14 Fingerprint convex portion 15 Finger recessed portion 21 Data driver 22 Scanning driver 23 Readout circuit 24 Image processing circuit 25 Panel 31 Capacitive fingerprint sensing unit 32 First transistor Finger capacitor 34 First transistor 35 Third transistor 36 Operational amplifier 37 > Worker 38 Control circuit 62 Wheel multiplexer 63 Part of the readout circuit Reference capacitor 124409.doc •11»