TWI774392B - Thin film transistor photo-sensing circuit, display panel and mobile device ushing the same - Google Patents
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本發明係關於一種生物辨識的技術，尤指採用薄膜電晶體感光電路之生物辨識技術、顯示面板以及使用其之行動裝置。 The present invention relates to a biometric identification technology, in particular to a biometric identification technology using a thin film transistor photosensitive circuit, a display panel and a mobile device using the same.
指紋辨識技術是一種生物辨識技術，指紋辨識系統是一套包括指紋圖像取得、處理、特徵提取和比對等模組的圖像識別系統。常用於需要人員身分確認的場所，如門禁系統、考勤系統、筆記型電腦、行動裝置、銀行內部處理與銀行支付等。目前應用於行動裝置使用的光學式指紋辨識分為按鈕式與屏下式。按鈕式指紋辨識裝置一般配置於行動裝置的開機按鈕或HOME按鈕，而屏下式指紋辨識裝置一般是配置在有機發光二極體面板下方的特定位置。然而，若使用者的手指不在特定位置，上述屏下式指紋辨識裝置則無法辨 識使用者的指紋。 Fingerprint identification technology is a kind of biometric identification technology, and the fingerprint identification system is a set of image identification system including modules of fingerprint image acquisition, processing, feature extraction and comparison. It is often used in places that require personnel identification, such as access control systems, time attendance systems, laptops, mobile devices, bank internal processing and bank payments, etc. Optical fingerprint recognition currently used in mobile devices is divided into a button type and an under-screen type. The button-type fingerprint identification device is generally disposed on the power-on button or the HOME button of the mobile device, while the under-screen fingerprint identification device is generally disposed at a specific position below the organic light-emitting diode panel. However, if the user's finger is not in a specific position, the above-mentioned under-screen fingerprint identification device cannot identify Identify the user's fingerprint.
另外，屏下式指紋辨識裝置需要有影像擷取裝置，一般影像擷取裝置主要是採用畫素感測器陣列，畫素感測器陣列包含被動式畫素感測器(Passive Pixel Sensor，PPS)與主動式畫素感測器(Active Pixel Sensor，APS)。兩種畫素感測器陣列主要的差別在於被動式畫素感測器的電路，是由單一個電晶體所構成的選擇開關。其中，當光線激發出上述電晶體的電子後，電子將儲存於電容器中，再讓位於每一行末端的放大器讀取出行、列交會處的畫素所積存的電訊號，再將此電訊號放大。被動式畫素感測器的優點是電路單純且不會因為占掉太多感光的面積而影響到感測器的靈敏度，缺點則是訊號的輸出線路阻抗極高，容易產生隨機雜訊造成影像的品質不佳。 In addition, the under-screen fingerprint identification device needs an image capture device. Generally, the image capture device mainly uses a pixel sensor array, and the pixel sensor array includes a passive pixel sensor (PPS). And active pixel sensor (Active Pixel Sensor, APS). The main difference between the two pixel sensor arrays is that the circuit of the passive pixel sensor is a selector switch composed of a single transistor. Among them, after the light excites the electrons of the above-mentioned transistors, the electrons will be stored in the capacitor, and then the amplifier at the end of each row reads the electrical signal stored in the pixels at the intersection of the row and column, and then uses the electrical signal enlarge. The advantage of passive pixel sensor is that the circuit is simple and will not affect the sensitivity of the sensor because it occupies too much photosensitive area. Poor quality.
主動式畫素感測器的電路是在每個畫素耦接電晶體所構成的放大器，此外主動式畫素感測器的設計解決了被動式畫素感測器容易產生隨機雜訊的問題，不過由於放大器的線路占掉畫素太多的感光面積，使感測器的單位面積內能放的畫素降低，解析度也隨之降低。此外，畫素上的放大器特性不容易做到每個都一致，導致有些畫素的電壓被放得較大，有些畫素的電壓放大的較小。製程完成後，這些放大器特性都不能更動。因此，會產生所謂的固定圖案雜訊，使擷取到的影像有如透過骯髒窗戶所看到的景物一般，所以目前大部分的產品所用的感測器還是以被動式畫素感測器為 主。 The circuit of the active pixel sensor is an amplifier composed of a transistor coupled to each pixel. In addition, the design of the active pixel sensor solves the problem that the passive pixel sensor is prone to random noise. However, because the circuit of the amplifier occupies too much of the photosensitive area of the pixels, the pixels that can be placed in the unit area of the sensor are reduced, and the resolution is also reduced. In addition, the characteristics of the amplifiers on the pixels are not easy to be consistent with each other, resulting in that the voltage of some pixels is amplified more, and the voltage of some pixels is amplified less. None of these amplifier characteristics can be changed after the process is complete. Therefore, the so-called fixed pattern noise will be generated, which makes the captured image look like the scene seen through a dirty window. Therefore, the sensors used in most products are still passive pixel sensors. host.
第1圖繪示為先前技術的光學指紋辨識裝置的影像擷取裝置之電路圖。請參考第1圖，在此實施例中，影像擷取裝置包括MxN個影像擷取單元與M個讀取電路110，每一個影像擷取單元包括一開關M1、儲能元件101以及一光電二極體(photodiode)102。一般來說，光電二極體102會採用P-I-N二極體結構，而P-I-N指的是P型摻雜、本質層(intrinsic layer)以及N型摻雜。也就是P型摻雜與N型摻雜之間，額外配置本質層。第2圖繪示為先前技術的光學指紋辨識裝置的影像擷取裝置之操作示意圖。請參考第2圖，在此例中，每一列都需要很長的積分時間，讓上述影像擷取單元內的儲能元件101累積電荷。在積分時間結束後，讀取電路110才可以讀取，並進行重置。然而，此類型的光學指紋辨識裝置的積分時間太長，且需要非常高強度的光源，對於屏下指紋辨識來說，常常會導致訊號雜訊比(SNR)不足使得指紋不清晰，甚至無法辨識。另外，若需要增加訊號雜訊比，則需要更長的時間讀取指紋，對產品來說，是一個很大的缺陷。
FIG. 1 is a circuit diagram of an image capturing device of an optical fingerprint identification device of the prior art. Please refer to FIG. 1 , in this embodiment, the image capture device includes M×N image capture units and
本發明的一目的在於提供一種薄膜電晶體感光電路、顯示面板以及使用其之行動裝置，用以採用薄膜電晶體製程製造感光速度快速的感光電路，能夠達成快速影像擷 取，適合用在面板下方的光學指紋辨識。 An object of the present invention is to provide a thin film transistor photosensitive circuit, a display panel and a mobile device using the same, which can be used to manufacture a photosensitive circuit with a fast photosensitive speed by using a thin film transistor process, which can achieve fast image capture It is suitable for optical fingerprint recognition under the panel.
有鑒於此，本發明提供一種薄膜電晶體感光電路，配置於一玻璃基板上，此薄膜電晶體感光電路包括M×N個感光單元、M個讀取電路以及一控制電路。每一感光單元包括一感光電路以及一開關電路。感光電路之感光部分由間隙型薄膜電晶體構成，包括一控制端、一第一端以及一第二端，其中，該感光電路的第一端耦接一第一電源端。開關電路包括一第一端、一第二端以及一控制端，其中，開關電路的第一端耦接感光電路的第二端。每一讀取電路包括一輸入端以及一輸出端，第K個讀取電路的輸入端，耦接第K列的N個開關電路的第二端。控制電路包括N個掃描端，第K個掃描端耦接第K列的M個感光電路的控制端以及M個開關電路的控制端。控制電路透過上述N個掃描端，依序掃描第一列~第N列的M個感光單元，以依序讀取出每一列的M個感光訊號，其中，當第K個掃描端致能時，第K列的M個感光電路以及M個開關電路同時被導通。 In view of this, the present invention provides a thin film transistor photosensitive circuit, which is disposed on a glass substrate. The thin film transistor photosensitive circuit includes M×N photosensitive units, M reading circuits and a control circuit. Each photosensitive unit includes a photosensitive circuit and a switch circuit. The photosensitive part of the photosensitive circuit is composed of a gap type thin film transistor, and includes a control end, a first end and a second end, wherein the first end of the photosensitive circuit is coupled to a first power end. The switch circuit includes a first terminal, a second terminal and a control terminal, wherein the first terminal of the switch circuit is coupled to the second terminal of the photosensitive circuit. Each readout circuit includes an input end and an output end, and the input end of the Kth readout circuit is coupled to the second end of the N switch circuits in the Kth column. The control circuit includes N scan terminals, and the K th scan terminal is coupled to the control terminals of the M photosensitive circuits in the K th column and the control terminals of the M switch circuits. The control circuit scans the M photosensitive units in the first row to the Nth row in sequence through the N scanning terminals, so as to sequentially read the M photosensitive signals in each row, wherein, when the Kth scanning terminal is enabled , the M photosensitive circuits and the M switch circuits in the Kth column are turned on at the same time.
本發明另外提供一種顯示面板，此顯示面板包括一指紋辨識裝置，配置於顯示面板下，此指紋辨識裝置包括一薄膜電晶體感光電路，此薄膜電晶體感光電路配置於一玻璃基板上，此薄膜電晶體感光電路如上所述。 The present invention further provides a display panel, the display panel includes a fingerprint identification device disposed under the display panel, the fingerprint identification device includes a thin film transistor photosensitive circuit, the thin film transistor photosensitive circuit is disposed on a glass substrate, the thin film The transistor photosensitive circuit is as described above.
本發明另外提供一種行動裝置，此行動裝置包括一顯示面板以及一指紋辨識裝置。指紋辨識裝置，配置於顯示面板下，此指紋辨識裝置包括一薄膜電晶體感光電路，此 薄膜電晶體感光電路配置於一玻璃基板上，此薄膜電晶體感光電路如上所述。 The present invention further provides a mobile device, the mobile device includes a display panel and a fingerprint identification device. The fingerprint identification device is arranged under the display panel. The fingerprint identification device includes a thin film transistor photosensitive circuit. The thin film transistor photosensitive circuit is disposed on a glass substrate, and the thin film transistor photosensitive circuit is as described above.
依照本發明較佳實施例所述之薄膜電晶體感光電路、顯示面板以及使用其之行動裝置，上述感光電路包括一間隙型薄膜電晶體，包括一閘極、一第一源汲極以及一第二源汲極，其中，間隙型薄膜電晶體的閘極耦接感光電路的控制端，間隙型薄膜電晶體的第一源汲極耦接感光電路的第一端，間隙型薄膜電晶體的第二源汲極耦接感光電路的第二端，其中，間隙型薄膜電晶體的非晶矽通道僅覆蓋一部分閘極。 According to the thin film transistor photosensitive circuit, the display panel and the mobile device using the same according to the preferred embodiment of the present invention, the photosensitive circuit includes a gap type thin film transistor, including a gate, a first source-drain and a first Two source-drain electrodes, wherein the gate electrode of the gap-type thin film transistor is coupled to the control terminal of the photosensitive circuit, the first source-drain electrode of the gap-type thin-film transistor is coupled to the first end of the photosensitive circuit, and the first terminal of the gap-type thin film transistor The two source-drain electrodes are coupled to the second end of the photosensitive circuit, wherein the amorphous silicon channel of the gap-type thin film transistor only covers a part of the gate electrode.
依照本發明較佳實施例所述之薄膜電晶體感光電路、顯示面板以及使用其之行動裝置，上述間隙型薄膜電晶體的閘極到第二源汲極之間隙長度介於2μm~10μm。 According to the thin film transistor photosensitive circuit, the display panel and the mobile device using the same according to the preferred embodiments of the present invention, the gap length from the gate to the second source-drain electrode of the gap-type thin film transistor is between 2 μm and 10 μm.
依照本發明較佳實施例所述之薄膜電晶體感光電路、顯示面板以及使用其之行動裝置，上述讀取電路包括一電阻電路以及一類比數位轉換器。第K個讀取電路的電阻電路的輸入端耦接第K列的開關電路的第二端。類比數位轉換器的輸入端耦接電阻電路的輸出端，其中，第K個讀取電路的類比數位轉換器的輸出端輸出被致能的第K個感光單元之感光數據。 According to the thin film transistor photosensitive circuit, the display panel and the mobile device using the same according to the preferred embodiment of the present invention, the reading circuit includes a resistance circuit and an analog digital converter. The input terminal of the resistance circuit of the Kth reading circuit is coupled to the second terminal of the switch circuit of the Kth column. The input terminal of the analog-to-digital converter is coupled to the output terminal of the resistance circuit, wherein the output terminal of the analog-to-digital converter of the K th reading circuit outputs the light-sensing data of the enabled K-th light-sensing unit.
依照本發明較佳實施例所述之薄膜電晶體感光電路、顯示面板以及使用其之行動裝置，上述每一讀取電路更包括一可控制電流源，包括一輸入端，其中，第K個可控 制電流源的輸入端耦接第K列的開關電路的第二端，可根據環境光線強度，調整可控制電流源之電流。 According to the thin film transistor photosensitive circuit, the display panel, and the mobile device using the same according to the preferred embodiment of the present invention, each reading circuit further includes a controllable current source, including an input terminal, wherein the Kth can be control The input end of the control current source is coupled to the second end of the switch circuit in the Kth row, and the current of the controllable current source can be adjusted according to the intensity of the ambient light.
依照本發明較佳實施例所述之薄膜電晶體感光電路、顯示面板以及使用其之行動裝置，上述可控制電流源包括一第一電晶體、一第二電晶體、一阻抗元件以及一數位類比轉換器。第一電晶體的第一源汲極耦接一電源電壓，第一電晶體的閘極耦接第一電晶體的第二源汲極，第一電晶體的第二源汲極耦接可控制電流源的輸入端。第二電晶體的第一源汲極耦接一電源電壓，第二電晶體的閘極耦接該第一電晶體的閘極。阻抗元件的第一端耦接第二電晶體的第二源汲極，阻抗元件的第二端耦接一共接電壓。數位類比轉換器的輸出端耦接第二電晶體的第二源汲極。其中，根據環境光線強度，調整數位類比轉換器的數據，以控制第一電晶體之電流。 According to the thin film transistor photosensitive circuit, the display panel and the mobile device using the same according to the preferred embodiments of the present invention, the controllable current source includes a first transistor, a second transistor, an impedance element and a digital analog converter. The first source-drain electrode of the first transistor is coupled to a power supply voltage, the gate electrode of the first transistor is coupled to the second source-drain electrode of the first transistor, and the second source-drain electrode of the first transistor is coupled to be controllable The input terminal of the current source. The first source-drain electrode of the second transistor is coupled to a power supply voltage, and the gate electrode of the second transistor is coupled to the gate electrode of the first transistor. The first end of the impedance element is coupled to the second source-drain of the second transistor, and the second end of the impedance element is coupled to a common voltage. The output end of the digital-to-analog converter is coupled to the second source-drain electrode of the second transistor. The data of the digital-to-analog converter is adjusted according to the intensity of ambient light to control the current of the first transistor.
本發明的精神在於利用間隙型薄膜電晶體作為感光電路，並且在玻璃基板上，以面板製程製作出間隙型薄膜電晶體的感光電路，除了具有非常大的成本優勢外，尺寸亦可以做的比矽基(silicon base)半導體更大。且感光效果遠大於光電二極體。故可以無須採用電容積分的方式，直接便可以讀取出感光結果。即便在薄膜電晶體的載子遷移率(mobility)遠小於矽基半導體材料的情況下，仍舊可以做到極快速的感光。 The spirit of the present invention is to use the gap-type thin film transistor as the photosensitive circuit, and to manufacture the photosensitive circuit of the gap-type thin film transistor on the glass substrate by the panel process. Silicon base semiconductors are larger. And the photosensitive effect is much greater than that of the photodiode. Therefore, the photosensitive result can be read directly without using the capacitor integration method. Even if the carrier mobility of thin film transistors is much smaller than that of silicon-based semiconductor materials, extremely fast photosensitivity can still be achieved.
為讓本發明之上述和其他目的、特徵和優點能更 明顯易懂，下文特舉較佳實施例，並配合所附圖式，作詳細說明如下。 To enable the above and other objects, features and advantages of the present invention to be further It is obvious and easy to understand. The preferred embodiments are exemplified below, and are described in detail as follows in conjunction with the accompanying drawings.
M1:開關 M1: switch
101:儲能元件 101: Energy storage element
102:光電二極體 102: Photodiode
110:讀取電路 110: read circuit
300:具有光學讀取功能之顯示面板 300: Display panel with optical reading function
301:配置於顯示面板300屏下之薄膜電晶體感光電路
301: a thin film transistor photosensitive circuit arranged under the
401:M×N個感光單元 401: M×N photosensitive units
402:M個讀取電路 402: M read circuits
403:控制電路 403: Control circuit
501:閘極金屬 501: Gate metal
502:閘極氧化層 502: gate oxide layer
503:通道 503: Channel
504:摻雜非晶矽 504: Doped Amorphous Silicon
505:源汲極金屬 505: source drain metal
60:感光單元 60: photosensitive unit
61:讀取電路 61: read circuit
62:控制電路 62: Control circuit
601:感光電路 601: Photosensitive circuit
602:開關電路 602: Switch circuit
MG:間隙型薄膜電晶體 MG: gap type thin film transistor
M2:薄膜電晶體 M2: Thin Film Transistor
611:電阻電路 611: Resistor Circuit
612:類比數位轉換器 612: Analog to Digital Converter
711:積分器 711: Integrator
801:可控制電流源 801: Controllable current source
901:第一電晶體 901: first transistor
902:第二電晶體 902: Second transistor
903:阻抗元件 903: Impedance element
904:數位類比轉換器 904: Digital to Analog Converter
VDD:電源電壓 VDD: Power supply voltage
1001、1002:閘極金屬 1001, 1002: Gate metal
第1圖繪示為先前技術的光學指紋辨識裝置的影像擷取裝置之電路圖。 FIG. 1 is a circuit diagram of an image capturing device of an optical fingerprint identification device of the prior art.
第2圖繪示為先前技術的光學指紋辨識裝置的影像擷取裝置之操作示意圖。 FIG. 2 is a schematic diagram illustrating the operation of the image capturing device of the optical fingerprint identification device of the prior art.
第3圖繪示為本發明一較佳實施例的行動裝置之示意圖。 FIG. 3 is a schematic diagram of a mobile device according to a preferred embodiment of the present invention.
第4圖繪示為本發明一較佳實施例的薄膜電晶體感光電路301之電路方塊圖。
FIG. 4 is a circuit block diagram of a thin film transistor
第5圖繪示為本發明一較佳實施例的間隙型薄膜電晶體之結構示意圖。 FIG. 5 is a schematic view of the structure of a gap-type thin film transistor according to a preferred embodiment of the present invention.
第6圖繪示為先前技術的薄膜電晶體之結構示意圖。 FIG. 6 is a schematic diagram of the structure of the thin film transistor of the prior art.
第7圖繪示為本發明一較佳實施例的薄膜電晶體感光電路之電路圖。 FIG. 7 is a circuit diagram of a thin film transistor photosensitive circuit according to a preferred embodiment of the present invention.
第8圖繪示為本發明一較佳實施例的薄膜電晶體感光電路之電路圖。 FIG. 8 is a circuit diagram of a thin film transistor photosensitive circuit according to a preferred embodiment of the present invention.
第9圖繪示為本發明一較佳實施例的可控制電流源801的電路圖。
FIG. 9 is a circuit diagram of a controllable
第10圖繪示為本發明一較佳實施例的間隙型薄膜電晶體之結構示意圖。 FIG. 10 is a schematic structural diagram of a gap-type thin film transistor according to a preferred embodiment of the present invention.
第3圖繪示為本發明一較佳實施例的行動裝置之示意圖。請參考第3圖，此行動裝置包括一具有光學讀取功能之顯示面板300以及配置於顯示面板300屏下之薄膜電晶體感光電路301。一般來說，面板下的光學讀取功能最常用的應用是指紋辨識，以下皆以指紋辨識作為舉例。顯示面板300例如為有機發光二極體面板。然本發明不以此為限。
FIG. 3 is a schematic diagram of a mobile device according to a preferred embodiment of the present invention. Please refer to FIG. 3 , the mobile device includes a
第4圖繪示為本發明一較佳實施例的薄膜電晶體感光電路301之電路方塊圖。請參考第4圖，此薄膜電晶體感光電路301包括M×N個感光單元401、M個讀取電路402以及控制電路403。感光單元401係配置在顯示面板下，例如由薄膜電晶體與間隙型薄膜電晶體構成。且感光單元401係採用面板製程，製作於玻璃基版上。
FIG. 4 is a circuit block diagram of a thin film transistor
第5圖繪示為本發明一較佳實施例的間隙型薄膜電晶體之結構示意圖。請參考第5圖，501為閘極金屬；502為閘極氧化層；503為通道，一般是用非晶矽製作；504為摻雜非晶矽；505為源汲極金屬。由第5圖可以看出，上述間隙型薄膜電晶體係以非對稱的結構，且露出非常大部分的薄膜電晶體通道，用以接收光線。在此實施例的間隙型薄膜電晶體之圖式中，標示出未重疊通道部份Li。藉此，間隙型薄膜電晶體便可以依照所接收的光線之不同，導通狀況也會跟著不同，進而判斷所接收的光線的亮暗程度。然而，習 知技術中的薄膜電晶體則是通道與閘極電極完全重疊，如圖6所示。通過比較圖5及圖6，可以看出，一般薄膜電晶體的通道LTFT和閘極完全重疊，且可以是對稱結構。 FIG. 5 is a schematic view of the structure of a gap-type thin film transistor according to a preferred embodiment of the present invention. Please refer to Figure 5, 501 is the gate metal; 502 is the gate oxide layer; 503 is the channel, which is generally made of amorphous silicon; 504 is doped amorphous silicon; 505 is the source-drain metal. It can be seen from FIG. 5 that the above-mentioned gap-type thin film transistor system has an asymmetric structure, and a very large part of the thin film transistor channel is exposed for receiving light. In the diagram of the gap-type thin film transistor of this embodiment, the non-overlapping channel portion Li is indicated. In this way, the gap-type thin film transistor can have different conduction states according to the received light, so as to judge the brightness and darkness of the received light. However, Xi The thin film transistor in the known technology completely overlaps the channel and the gate electrode, as shown in FIG. 6 . By comparing FIG. 5 and FIG. 6 , it can be seen that the channel LTFT and the gate electrode of a general thin film transistor completely overlap, and can be a symmetrical structure.
第7圖繪示為本發明一較佳實施例的薄膜電晶體感光電路之電路圖。請參考第7圖，在此實施例中，為了方便說明本發明的精神，僅繪示2×2的感光單元，然所屬技術領域具有通常知識者應當知道，感光單元的數量與配置可以依照不同設計而擴展，故本發明不以此為限。此薄膜電晶體感光電路包括多個感光單元60、多個讀取電路61以及控制電路62，每一個感光單元60包括一感光電路601以及一開關電路602。感光電路601在此實施例例如是以單一個間隙型薄膜電晶體MMG所構成，在第7圖的圖式內是以閘極電極一半來表示。開關電路602例如以普通薄膜電晶體M2實施。讀取電路61例如以電阻電路611以及類比數位轉換器612實施。
FIG. 7 is a circuit diagram of a thin film transistor photosensitive circuit according to a preferred embodiment of the present invention. Please refer to FIG. 7. In this embodiment, for the convenience of explaining the spirit of the present invention, only 2×2 photosensitive units are shown. However, those skilled in the art should know that the number and configuration of the photosensitive units may vary according to Design and expansion, so the present invention is not limited to this. The thin film transistor photosensitive circuit includes a plurality of
在此實施例中，感光電路601與開關電路602的控制端皆耦接於控制電路62，且控制電路62例如以掃描的方式進行感光，也就是說，在第一掃描時間，控制電路62控制掃描線G0致能，並透過讀取電路61讀取出資料DAT_1與DAT_2。接著，在第二掃描時間，控制電路62控制掃描線G1致能，並透過讀取電路61讀取出資料DAT_1與DAT_2…以此類推。然而，較為特別的是，在此實施例中，感光電路601的間隙型薄膜電晶體MG的一源汲極並未耦接儲能元件，
而是耦接開關電路602，間隙型薄膜電晶體MG的另一源汲極則耦接電源端。由於在此實施例中，間隙型薄膜電晶體MG的光電流比起先前技術的光電二極體之光電流超過千倍，故在此實施例中，讀取電路61僅採用簡單的電阻電路611以及類比數位轉換器612結構，並沒有如先前技術採用積分器，原因在於，本發明實施例的感光電路601的光電流已夠大到可以使用電阻直接讀取感光後的電壓，所需累積(積分)的時間也可以大幅減少。故在此實施例中，每列的閘極會依序被開啟，開啟的同時便可以讀取訊號值。故本發明實施例的薄膜電晶體感光電路之讀取速度的優勢更明顯。雖然上述實施例中採用簡單的電阻電路611作為本發明範例說明，然所屬技術領域具有通常知識者應當知道，本發明亦可以採用積分器作為讀取電路61，故本發明不以此為限。
In this embodiment, the control terminals of the light-
上述實施例中，薄膜電晶體感光電路601可以是製作在玻璃基板上的。若以半導體製程，做大面積的光學指紋辨識電路，價格會十分昂貴。然在本實施例中，採用玻璃基板與薄膜電晶體製程製作，成本上具有極大的優勢。另外，對比先前技術採用的光電二極體，若同樣將光電二極體利用玻璃基板與薄膜電晶體製程製作，將導致需要許多額外的光罩，並不能和原本液晶顯示面板採用同樣層數的光罩。而本發明所採用的一般薄膜電晶體以及間隙型薄膜電晶體，在製程上，完全可以採用原本面板的製程。
In the above embodiments, the thin film transistor
第8圖繪示為本發明一較佳實施例的薄膜電晶
體感光電路之電路圖。請參考第6圖以及第8圖，同樣地，為了方便說明本發明的精神，僅繪示2×2的感光單元，在此實施例中，在每一行的開關電路602，另外耦接一可控制電流源801，為了清楚說明，標示了節點Z。此可控制電流源801係根據環境光的亮度調整電流大小。舉例來說，由於本發明實施例的間隙型薄膜電晶體MG對光的敏感度極高，若環境光線較強，很可能瞬間飽和，導致指紋無法辨識。故在此實施例中，採用一根據環境光線調整的可控制電流源801。利用可控制電流源801調整電流，進行對指紋的校準(calibration)。
FIG. 8 shows a thin film transistor according to a preferred embodiment of the present invention
The circuit diagram of the body photosensitive circuit. Please refer to FIG. 6 and FIG. 8. Similarly, for the convenience of explaining the spirit of the present invention, only 2×2 photosensitive units are shown. In this embodiment, the
第9圖繪示為本發明一較佳實施例的可控制電流源801的電路圖。請參考第9圖，在此實施例中，可控制電流源包括一第一電晶體901、第二電晶體902、阻抗元件903以及一數位類比轉換器904。在此實施例中，第一電晶體901的第一源汲極耦接電源電壓VDD，第一電晶體901的第二源汲極耦接節點Z以及第一電晶體901的閘極。第一電晶體901的閘極耦接第二電晶體902，的閘極。第二電晶體902的第一源汲極耦接電源電壓VDD，第二電晶體902的第二源汲極耦接阻抗元件903以及數位類比轉換器904的輸出端。在此實施例中，藉由數位類比轉換器904控制第一電晶體901的電流之大小。數位類比轉換器904則根據環境光的亮度之數據改變其輸出的類比電壓。藉此，可以根據環境光的強弱，進行對指紋的校準。
FIG. 9 is a circuit diagram of a controllable
第10圖繪示為本發明一較佳實施例的間隙型薄膜電晶體之結構示意圖。通過比較圖5和圖10，可以看出，第10圖具有兩個閘極金屬1001以及1002。同樣地，通道與兩個閘極金屬1001以及1002重疊處僅一部分。故本發明並不以第5圖的實施例為限。
FIG. 10 is a schematic structural diagram of a gap-type thin film transistor according to a preferred embodiment of the present invention. By comparing FIG. 5 and FIG. 10 , it can be seen that FIG. 10 has two
表一為本發明實施例的間隙型薄膜電晶體的間隙長度，例如圖5中的Li，對光電流大小的比較表。在下表一中，分別以2um、6um以及10um進行測試，並且測試條件設定在汲極電壓VD和閘極電壓VG等於20V並進行了21次測試，每次間隔30秒。由下述表一可以看出，2um的間隙之間隙型薄膜電晶體的光電流有8.689uA，6um的間隙之間隙型薄膜電晶體的光電流有3.446nA，而10um的間隙之間隙型薄膜電晶體的光電流有0.805nA。另外，變化量也是2um的間隙之間隙型薄膜電晶體表現較為出色。然而，2~10um的間隙型薄膜電晶體皆在本發明的實施例之應用範圍內。也就是說，實施例之間隙型薄膜電晶體的間隙長度Li亦可定義從閘極一側的邊緣至源汲極邊緣或未重疊通道部份，可以是介於2~10um。 Table 1 is a comparison table of the gap length of the gap-type thin film transistor according to the embodiment of the present invention, such as Li in FIG. 5 , and the magnitude of the photocurrent. In Table 1 below, the tests were performed at 2um, 6um and 10um respectively, and the test conditions were set at the drain voltage VD and the gate voltage VG equal to 20V and 21 tests were performed, each with an interval of 30 seconds. It can be seen from Table 1 below that the photocurrent of the gap TFT with a gap of 2um is 8.689uA, the photocurrent of the gap TFT with a gap of 6um is 3.446nA, and the gap TFT with a gap of 10um has a photocurrent of 3.446nA. The photocurrent of the crystal is 0.805nA. In addition, the gap-type thin film transistor with a gap of 2um in the amount of change performs better. However, gap-type thin film transistors of 2-10 um are all within the scope of application of the embodiments of the present invention. That is to say, the gap length Li of the gap-type thin film transistor of the embodiment can also be defined from the edge of the gate side to the edge of the source-drain electrode or the non-overlapping channel portion, which can be between 2 and 10 μm.
綜上所述，本發明的精神在於利用間隙型薄膜電晶體作為感光電路，並且在玻璃基板上，以面板製程製作出間隙型薄膜電晶體的感光電路，除了具有非常大的成本優勢外，實際製作的尺寸亦可以比矽基(silicon base)半導體更大。且感光效果遠大於光電二極體。故可以無須採用電容積分的方式，直接便可以讀取出感光結果。即便在薄膜電晶體的載子遷移率(mobility)遠小於矽基半導體材料的情況下，仍舊可以做到極快速的感光。 To sum up, the spirit of the present invention is to use the gap-type thin film transistor as the photosensitive circuit, and to manufacture the photosensitive circuit of the gap-type thin film transistor on the glass substrate by the panel process. The size of fabrication can also be larger than that of silicon base semiconductors. And the photosensitive effect is much greater than that of the photodiode. Therefore, the photosensitive result can be read directly without using the capacitor integration method. Even if the carrier mobility of thin film transistors is much smaller than that of silicon-based semiconductor materials, extremely fast photosensitivity can still be achieved.
在較佳實施例之詳細說明中所提出之具體實施例僅用以方便說明本發明之技術內容，而非將本發明狹義地限制於上述實施例，在不超出本發明之精神及以下申請專利範圍之情況，所做之種種變化實施，皆屬於本發明之範圍。因此本發明之保護範圍當視後附之申請專利範圍所界定者為準。 The specific embodiments proposed in the detailed description of the preferred embodiments are only used to facilitate the description of the technical content of the present invention, rather than restricting the present invention to the above-mentioned embodiments in a narrow sense, without exceeding the spirit of the present invention and applying for patents below The situation of the scope, the various changes and implementations made, all belong to the scope of the present invention. Therefore, the protection scope of the present invention should be determined by the scope of the appended patent application.
60:感光單元 60: photosensitive unit
61:讀取電路 61: read circuit
62:控制電路 62: Control circuit
601:感光電路 601: Photosensitive circuit
602:開關電路 602: Switch circuit
MG:間隙型薄膜電晶體 MG: gap type thin film transistor
M2:薄膜電晶體 M2: Thin Film Transistor
611:電阻電路 611: Resistor Circuit
612:類比數位轉換器 612: Analog to Digital Converter
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| CN101592810A (en) * | 2008-05-27 | 2009-12-02 | 乐金显示有限公司 | Liquid crystal display |
| US20170040350A1 (en) * | 2009-10-16 | 2017-02-09 | Semiconductor Energy Laboratory Co., Ltd. | Logic circuit and semiconductor device |
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